Organic Chemistry - NZ Science Class Online

Organic Chemistry - NZ Science Class Online

2017 Version Chemistry AS 91391 C3.5 Organic Chemistry Achievement Criteria This achievement standard involves describing the structure, physical properties, and reactions of organic compounds. AS 91391 C3.5 Organic compounds will be limited to those containing one or more of the following functional groups: alkene, haloalkane, amine, alcohol, aldehyde, ketone, carboxylic acid, ester (including triglycerides), acyl chloride, amide. Reactivity of organic compounds will be limited to substitution reactions using the following reagents: concentrated HCl, HBr, ZnCl 2/HCl, SOCl2, PCl3, NaOH, KOH (in alcohol or aqueous solution), concentrated NH3, primary amines, primary alcohols/H+, primary alcohols, H2O/H+, H2O/OH (Substitution reactions include esterification, condensation, hydrolysis, and polymerisation.) oxidation reactions using the following reagents: MnO4/H+, Cr2O72/H+, Tollens, Fehlings and Benedicts. Reduction of aldehydes and ketones with LiAlH4

elimination reactions using the following reagents: KOH in alcohol and concentrated H 2SO4 (includes major and minor products from asymmetric alcohols and haloalkanes) polymerisation reactions of formation of polyesters and polyamides including proteins addition reactions of alkenes (used for the identification of the products of elimination reactions). Appropriate information relating to other oxidants or reductants will be provided. Physical properties of organic compounds will be limited to solubility melting point and boiling point rotation of plane-polarised light. Ba Kn ck ow gro le un dg d e Organic chemistry as the chemistry of compounds that contain both carbon and hydrogen Carbon has four valence electrons. The

electronegativity of carbon is too small for carbon to gain electrons from most elements to form C4- ions, and too large for carbon to lose electrons to form C4+ ions. Carbon therefore forms covalent bonds with a large number of other elements, including the hydrogen, nitrogen, oxygen, phosphorus, and sulfur. Ba Kn ck ow gro le un dg d e Organic Chemistry Formula Molecular Formula type and number of each atom. i.e. Propane C3H8 Structural Formula placement of each atom. Condensed Structural Formula

CH3-CH2-CH3 Structural isomers are molecules with the same molecular formula but different structural formula. Functional Groups Alkene Derivatives Functional Groups Carboxylic Derivatives Ba Kn ck ow gro le un dg d e generic formula CnH2n+2 Alkanes Compounds that contain only carbon and hydrogen are known as hydrocarbons. Those that contain as many

hydrogen atoms as possible are said to be saturated. The saturated hydrocarbons are also known as alkanes. Straight-chain hydrocarbons, in which the carbon atoms form a chain that runs from one end of the molecule to the other .i.e. butane H H H H H C C C C H

H H H H Alkanes also form branched structures. The smallest hydrocarbon in which a branch can occur has four carbon atoms. This compound has the same formula as butane (C4H10), but a different structure. Compounds with the same formula and different Ba Kn ck ow gro le un dg d e Chemical properties of Alkanes 1.

2. 3. 4. 5. 6. Non reactivity of alkanes (in relation to acids, alkalis, metals, water, because they are non-polar molecules). Low melting and boiling points intermolecular forces are weak van der Waal forces. Odour hydrocarbons are volatile because they have weak intermolecular forces and they have characteristic smells. Do not conduct heat or electricity. As the C chain gets longer the hydrocarbons change from gas to liquid to solid. Combustion of alkanes. Alkanes are very good fuels. Prefixes are used to indicate number of carbon atoms in the longest carbon chain

Naming Alkanes Write name as 1. Identify the longest C chain 2. Identify any branches 3. Number the C atoms in longest chain 4. so branches are on the lowest numbers 5. Write the name 1. Location of branch 2. Name of branch 3. Prefix of long chain 4. -ane Naming Branches IUPAC Rules for Alkane Nomenclature 1. Find and name the longest continuous carbon chain. 2. Identify and name groups attached to this chain. 3. Number the chain consecutively, starting at the end nearest a substituent group. 4. Designate the location of each substituent group by an appropriate number and name. 5. Assemble the name, listing groups in alphabetical order. The prefixes di, tri, tetra etc., used to designate several groups of the

same kind, are not considered when alphabetising. methyl 1 ethyl 2 propyl 3 -CH3 -CH2CH3 -CH2CH2CH3 Ba Kn ck ow gro le un dg d e

Naming Branched chain Alkanes Always make sure the longest possible chain of carbons and therefore the shortest possible branches is used. Ba Kn ck ow gro le un dg d e Naming cyclic Alkanes Alkanes can also form cyclic molecules. These are named by placing cyclo- in front of the longest chain. At this level knowledge of branched chain cyclic alkanes is not required cyclopropane cyclobutane cyclohexane Ba

Kn ck ow gro le un dg d e Alkanes are non-polar molecules and are bonded together by weak intermolecular forces. As the number of carbons increase so does the Molar Mass of the molecule. The larger the molar mass the more total valence electrons are available. Melting and boiling points of alkanes These valance electrons can randomly cluster on one side or the other creating an instantaneous polar end thereby creating a bond to another molecules instantaneous polar end The greater the number of carbons the stronger the bond between molecules therefore the higher the

melting and boiling point. Alkenes Functional Group One double carbon-carbon bond C=C A functional group is the part of the molecule responsible for reactions typical of the homologous series. Alkene Nomenclature Alkenes are named in a similar way to alkanes, but the longest continuous carbon chain is numbered to give the carbon atoms in the double bond the lowest possible numbers. The position of the double bond is given by the smaller number of the two carbon atoms involved. H After numbering the longest chain C1-C2=C3-C4, the compound is named 2-butene or but-2-ene, but not 3-butene nor but-3-ene. generic formula CnH2n H H

C C H C H H C H H Naming Alkenes H H Write name as 1. Location of branch

C H H H 4. Location of C=C 5. -ene C H H H C 2. Name of branch 3. Prefix of long chain H H C

C C C H H H H 6. If in an alkene there are more than one double bond is present, it named as a diene or triene. For example; 2,5-Dimethyl-2,4-hexadiene, here double bond located at 2 and 4 position with two substituent (methyl group) at 2 and 5 positions. Number carbons so double bond has the lowest number. The Alkene shown above is found to be 4-methylhex-2-ene by numbering the chain C1C2=C3-C4-C5-C6. Ba Kn ck ow gro

le un dg d e Summary of solubility in Water Alkanes and Alkenes Alkanes and Alkenes: Not soluble in water. These molecules are non-polar (there is no negative or positive ends to the molecule) compared with water which is polar (having a negative area near the oxygen atom and positive area near the hydrogen atoms) so they are not attracted to each other. Alkanes and alkenes are immiscible (two or more liquids that will not mix together to form a single homogeneous substance) and form a distinct layer from the water. Smaller C chained alkanes and alkenes are less dense than water and float on top. If either an Alkane or Alkene is mixed into water eventually the two liquids will form separate immiscible layers Haloalkanes (alkyl halides)

Named as a chloroalkane or bromoalkane etc, with the position of the halogen given by the appropriate number of the carbon that it is attached to in the chain. The haloalkanes can be classified as Primary RCH2X - the C atom to which X is attached is only attached to one other C atom Secondary R2CHX - the C atom to which X is attached, is attached to two other C atoms Tertiary R3CX - the C atom to which X is attached, is attached to three other C atoms. Naming Haloalkanes Haloalkanes are classified according to the position of the halogen atom bonded in the molecule. This leads to the existence of >primary (1) bonded to a C that is bonded to only 1 other C >secondary (2) bonded to a C that is bonded to 2 other C >tertiary (3) bonded to a C that is bonded to 3 other C H H

H H H C C C C H H H H 1-chlorobutane

Cl H (1haloalkane) H 2-chlorobutane (2haloalkane) H H H H H C C

C C H H Cl H H H C H H C C

C H Cl H H H 2-chloro-2-methylpropane (3haloalkane) Haloalkane Prefixes Atom Name used in haloalkane Bromine Chlorine

Fluorine iodine Bromo Chloro Fluoro iodo Ba Kn ck ow gro le un dg d e Naming Alkynes H The Alkyne shown below is found to be 4-methylhex-1-yne by numbering the chain C1-C2-C3-C4-C5-C6. C

C H H H H C C C C H H C H

H H H H Write name as 1.Location of branch 2. Name of branch Addition reactions of Alkynes are similar to Alkene 3.Prefix of long chain 4. Location_of C=C First break triple bond to double bond- adding atoms and forming Alkene 5.-yne Next break double bond adding atoms and

forming Alkane Alcohol Alcohols are not considered hydrocarbons as they have one or more oxygen atoms attached in addition to the hydrogen and carbon atoms. Alcohols are organic substances however and share many of the same chemical and physical properties of the alkanes and alkenes. Alcohols are used as solvents and fuels and ethanol (a two carbon alcohol) is used as a drink. Alcohol Functional group is the hydroxyl group OH (not a hydroxide) Naming alcohols H H C H 1. Location of branch H

C H 2. Name of branch H C H 3. Prefix of long chain H C H 4. an- O H

Butan-1-ol 5. Location of OH (if multiple di, tri, tetra) 6. -ol Alcohols are classified according to the position of the hydroxyl group bonded in the molecule. This leads to the existence of >primary (1) bonded to a C that is bonded to only 1 other C >secondary (2) bonded to a C that is bonded to 2 other C >tertiary (3) bonded to a C that is bonded to 3 other C Ba Kn ck ow gro le un dg d e Alcohol properties Small alcohol molecules are polar and the presence of the OH group means they are able to undergo

intermolecular hydrogen bonding. The large difference in electronegativity between the O and H atoms means the O-H bond is very polar and the slightly positive charge on this H atom is attracted to the non-bonding electron pairs of the oxygen on another molecule. This means small alcohol molecules are highly soluble in water. However as the length of the non-polar hydrocarbon chain increases this solubility in water decreases. Aqueous solutions are neutral. The presence of the OH group in this molecule is NOT the same as the OH- in sodium hydroxide, NaOH (an ionic compound). Summary of solubility in Water - Alcohol Alcohols: Soluble in water. These molecules are polar (due to the OH end) and water, also being polar, will bond with the alcohol. The alcohol molecules will therefore disperse and mix within the water molecules. At the instant ethanol and water are mixed the ethanol floats on top of the water Hydrogen bonds between ethanol

molecules. Because the attractions between their molecules are similar, the molecules mix freely, allowing each substance to disperse into the other Hydrogen bonds between water molecules. Ethanol and water mix. Hydrogen bonds between ethanol and water molecules. Summary of Boiling points Alkanes: The smaller the alkane molecule the lower the boiling point and the more

volatile (easier to combust) the alkane. As the molar mass (Mass number of all the atoms combined) increases, the boiling points also increase as the strength of the intermolecular (between molecules) attractions increases. The alkanes methane to butane (C1 C4) are all gases at room temperature Alkanes with between 5C and 15C atoms are all liquids Alkanes with over 15 C atoms are soft solids Alkenes: The boiling point trend is similar to alkanes where the larger the number of C atoms in the chain the higher the boiling point. The equivalent length C chain alkene has a slightly higher point than that of the alkanes. Alcohols: The boiling point trend is similar to both alkanes and alkenes where the larger the number of C atoms in the chain the higher the boiling point. The boiling point is higher than both alkanes and alkenes as the intermolecular bonding is stronger due to being a polar molecule which creates a positive and negative end and hold the individual alcohol molecules together stronger and thus needs more energy to break them (heat energy) Even small chain alcohols are liquid at room temperature Amines Functional group is the amino group NH3 Amines are named as substituents eg aminomethane, CH3NH2. These may be classed as primary, secondary or tertiary, but their classification depends on the number of C atoms

attached to the N atom. Primary RNH2, secondary R2NH, tertiary R3N. Amines have an unpleasant ammonia smell. The smaller amines, up to C5, are soluble in water but larger amino alkanes are insoluble, as the size of the non-polar hydrocarbon chain cancels out the effect of the polar amino (mainly due to lone pair of electrons on the N) functional group Naming Primary Amines Write name as 1. Identify the longest C chain -Identify any branches 2. Number the C atoms in longest chain so number Carbon 1 attached to amino group (NH2) 3. Write the name Alternative naming method 1. Location of branch 1.Identify the longest C chain - Identify any branches

2. Name of branch 3. Amino- 2.Number the C atoms in longest chain so number Carbon 1 attached to amino group (NH2) 4. Prefix of long chain 3.Write the name 5. -ane 1. Location of branch e.g. aminobutane (4C) 2. Name of branch 3. Prefix of long chain Either will be accepted in NCEA assessments 4. -anamine

e.g. butanamine (4C) Names and Classification Amines can be classified as 1o, 2o or 3o according to the number of R groups on the nitrogen. The N is a placeholder for a number as it is not off a carbon 1o 2o 3o 1 R group on amino nitrogen (and 2H) 2 R groups on amino nitrogen (and 1H) 3 R groups on amino nitrogen

(and no H) H R N H H R N R R R N R If the amino group NH2 is not on the end carbon then name the

compound as you would a branch For example 2-amino If the groups off the N are different then name each separately For example N-ethyl N-methyl Bonding and physical properties Intermolecular bonding results from hydrogen bonding between the NH groups and ID-ID attractions from the hydrocarbon portions. States -Aminomethane and aminoethane are gases. -Aminopropane and aminobutane are volatile liquids with fishy smells. -Heavier aminoalkanes are solids. Solubility in water Lower molecular mass aminoalkanes are soluble in water due to hydrogen bonding. Solubility in water

decreases as hydrocarbon portion increases. Carboxylic Acids Functional group is the carboxyl group COOH Naming carboxylic acids H H H C C H H 1. Longest C chain with -COOH O

2. Identify branches C 3. No. 1 C is the C in -COOH 4. Location of branches O H propanoic acid 5. Name branch 6. Prefic 7. -anoic acid >polar molecules as short chains ~ non-polar molecules as long chains >boiling points and melting points decrease with chain length >turn blue litmus red (weakly acidic) >conduct electricity >react with metal to form salt and H2 >react with metal oxides to form salt and H2O >react with metal carbonates to form salt and H2O and CO2

Carboxylic Acids All the simple, straight-chain carboxylic acids up to ten carbons are liquids at room temperature. The liquids have sharp pungent odours and all have high boiling points. Smaller molecules, less than 10 carbons, are completely miscible in water due to the formation of hydrogen bonds with the water. The highly polar carboxylic acids dimerise in the liquid phase and in nonaqueous solvents (CCl4) and form two hydrogen bonds between each pair. This extra degree of hydrogen bonding causes carboxylic acids to have higher boiling points compared to their corresponding alcohols. Carboxylic Acid properties All the simple, straight-chain carboxylic acids up to ten carbons are liquids at room temperature. The liquids have sharp pungent odours and all have high boiling points. Smaller molecules, less than 10 carbons, are completely miscible in water due

to the formation of hydrogen bonds with the water. The highly polar carboxylic acids dimerise in the liquid phase and in nonaqueous solvents (CCl4) and form two hydrogen bonds between each pair. This extra degree of hydrogen bonding causes carboxylic acids to have higher boiling points compared to their corresponding alcohols. Aldehydes Aldehydes are a class of organic compounds that are important in the manufacture of plastics, dyes, food additives, and other chemical compounds. Aldehydes have the general formula -RCHO Where R is either a hydrogen atom, as in the case of formaldehyde, or an aromatic hydrocarbon group. Formaldehyde is used extensively in the chemical industry in the synthesis of organic compounds. Its most important use is in the manufacture of synthetic resins. Recent tests have indicated that it is a carcinogen.

C H O Aldehydes Naming Functional group is the group RCHO Aldehydes are named by changing -e at the end of the alkane to -al. The aldehyde group does not need to be numbered when naming an aldehyde as it must always be on the end carbon (carbon number 1). If there are other substituents in the molecule then numbering is always from the aldehyde end of the chain. Ketones Functional group is the group (alkanones - RCOR') Ketones are named by changing -e on alkanes to -one. Ketones (apart from propanone and butanone where there is no choice) need a number to indicate the position

of the carbonyl (C=O) group. pentan-2-one C H O Ketones Ketones are a class of organic compounds of the general structure RCOR, in which R and R represent organic radicals. The simplest ketone is acetone (CH3COCH3). Acetone is a product of the metabolism of fats, but under ordinary conditions it oxidizes quickly to water and carbon dioxide. In diabetes mellitus, however, acetone accumulates in the body. Other ketones are camphor, many steroids, some fragrances, and some sugars. Ketones are relatively reactive organic compounds and thus are invaluable in synthesizing other compounds; they are also important intermediates in cell metabolism.

Ketones Optical Isomers Carvone is a ketone that forms two optical isomers or enantiomers: () carvone smells like spearmint. Its mirror image, (+) carvone, smells like caraway. Humans have olfactory receptors in their noses which can distinguish between the chiral ketones, allowing them to notice significant differences in smell between spearmint and caraway. Alcohols, aldehydes, ketones and carboxylic acids Primary alcohol Secondary alcohol tertiary alcohol

-ol aldehyde ketone No Reaction -al -one Carboxylic acid -anoic acid C H O Acid Chlorides (acyl chlorides) Formed from carboxylic acids, with a -Cl replacing the OH Functional Group:

-COCl Naming suffix is -oyl chloride prefix is alkyl group including the carbon on the -COCl group e.g. ethan Physical Properties low MPs and BPs as there is no H bonding on the functional group. liquids which fume in moist air and have an irritating smell (due to rapid hydrolysis reaction) C H O Cl Amides Functional Group

-CONH2 Formed from carboxylic acids with a NH2 substituting the -OH. Physical Properties methanamide is liquid, the rest are odourless solids. (impure ethanamide smells like mice) The higher melting points are due to dimerisation caused by hydrogen bonding. A dimer is a chemical entity consisting of two structurally similar subunits called monomers joined by bonds that can be either strong or weak C H O

N Amide classification Classification as 1o, 2o, 3o 1o no alkyls and 2 hydrogens R C on N O NH2 2o ethanamide 1 alkyl and 1 hydrogen on N O R C

NH R' 3 o N-methylethanamide 2 alkyls and no hydrogen on N O R' C R N R' N,N-dimethylethanamide Amide naming

1. Indicate whether 1 - The N is only attached to one C group (no N in front of name) 2. Indicate whether 2 - The N is attached to 2 C groups ( place an N in front of the name 3. Indicate whether 3 - The N is attached to 3 C groups (place an N,N in front of the name 4. Name the groups off the N (not the long parent C chain) as branches 5. Name the longest C chain 6. Suffix - anamide CH3 O C CH3 N CH3 N,N-dimethylethanamide Esters Functional group is COONaming esters

H H C C H H 1. Split between C-O bond O H 2. Identify name for side with O- C 3. Prefix of C chain O H

C H 4. -yl H 5. Identify name for side with C=O C H H 6. Prefix of C chain 7. -anoate Ethyl propanoate Esters often have fruity or distinctive smells Prepared by the process of esterification Esters Esters are chemical compounds responsible for

the fruity smells present in processed food. Many natural flavours and smells are due to the presence of esters in flowers and fruits. The higher the molecular weight, the weaker the odours they carry are. alcohol pentanol octanol pentanol methanol organic acid ester made smell of ester ethanoic pentyl pears acid ethanoate ethanoic octyl acid ethanoate bananas butanoic

pentyl strawberries acid butanoate butanoic methyl pineapples acid butanoate Merit Question NCEA 2013 Functional Groups Question 1a: Complete the table below by giving the IUPAC systematic name or the structural formula for each compound. 3-hydroxy propanal / hydroxyl propanal 3- 4-methyl pentan-2-one

NCEA 2014 Functional Groups Question 1(a): Complete the table below giving the IUPAC systematic name or the structural formula for each compound. 3-chlorobutanone CH3 CH2 CO NH2 methylbutanoate Achieved Question NCEA 2015 Functional Groups Achieved Question Question 1(a): The structure of aspartame is given below. Aspartame is often used as an artificial sweetener in drinks. Identify the FOUR different functional groups within the aspartame molecule that are circled and numbered below: Answer:

1. Carboxylic acid or carboxyl 3. Amide 2. Amine or aminoalkane 4. Ester NCEA 2015 Functional Groups Achieved Question Question 1(b): Complete the table below by drawing the structural formula for the named compounds. NCEA 2015 Isomers (Haloalkanes) Merit Question Question 1(c) (i) : In the boxes below, draw the three structural isomers of C 4H9Cl that represent a primary, secondary and tertiary haloalkane. H3CCH2CH2CH2Cl or H3CCH2CH(CH3)Cl

H3CCH(Cl)CH2CH3 H3CCCl(CH3)CH3 NCEA 2016 Functional Groups Question 1a: Complete the table below by drawing the structural formula for the named compounds. Achieved Question Achieved Question NCEA 2016 Functional Groups Question 1b: The structure of amoxycillin is given below. It is an antibiotic used in the treatment of bacterial infections. Name the four different functional groups circled within the amoxycillin molecule above. Hydroxyl (alcohol). Amide / peptide.

Amine / amino. Carboxylic acid. Achieved Question NCEA 2016 Functional Groups Question 2b: The structures of four different organic substances are shown in the table below. (i) Name the organic substances A to D. Propan-1-amine. (1-propanamine) Propanal.

Propanoyl chloride. Propan-2-one. (propanone) Stereoisomers Two molecules are described as stereoisomers of each other if they consist of the same atoms, that are connected in the same sequence, but the atoms are positioned differently in space. The difference between two stereoisomers can only be seen from the three dimensional arrangement of the molecules. Stereoisomers are a type of isomer (variety).Stereoisomers can be subdivided into geometric isomers and optical isomers. Geometric Isomers Alkenes can exist as geometrical or cis-trans isomers, a form of stereoisomerism. A simple example is but-2-ene. To exist as geometrical isomers the C atoms at both ends of the double bond must each have two different groups (or atoms) attached. It is impossible for a 1-alkene to have geometric isomers since the first C atom in the chain has two identical H atoms. H H H H

C C H H C H H C H Cis but-2-ene H C H

C H H C H C H H Trans but-2-ene NOTE: (i) The cis or trans prefix must be included when naming these alkenes. (ii) Bond angles around a double bonded C are 120o; and the shape is trigonal planar (iii) Bond angles around the triple bonded C found in an alkyne are 180 o, shape is linear. Optical isomers Optical Isomers or Enantiomers

Optical isomers (like geometric isomers) are examples of stereoisomers. The enantiomer and its mirror image are non-identical. All amino acids, (except the simplest amino acid, glycine), are optically active. This means they contain an asymmetric, or chiral, carbon atom. This is a carbon atom which has four different groups attached. To show the different enantiomers of a molecule it is necessary to draw a 3-dimensional structure. For any enantiomer the structure of the mirror image can be drawn by swapping any two groups. Optical isomers Enantiomers have identical physical properties (melting point, solubility etc) BUT differ in that they rotate plane polarised light in opposite directions. Optical isomers Optical isomers cannot be superimposed. If two of the groups are the same around the chiral carbon then the molecule can be turned 180 and be superimposed therefore it is not an optical

isomer. Optical isomers A chiral molecule is a type of molecule that lacks an internal plane of symmetry and has a non-superimposable mirror image. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom. The term chiral (pronounced in general is used to describe an object that is nonsuper-imposible on its mirror image. Achiral (not chiral) objects are objects that are identical to their mirror image. In chemistry, chirality usually refers to molecules. Two mirror images of a chiral molecule are called enantomers or optical isomers. Pairs of enantiomers are often designated as right-" and "left-handed." NCEA 2013 Optical Isomers Merit Question

Question 1b: (i) The alcohol below can exist as two enantiomers (optical isomers). (i) Draw three-dimensional structures for the two enantiomers. Question 1b: (ii) Link the structure of enantiomers to a physical property that can be used to distinguish them from non-optically active molecules. Enantiomers exist for atoms containing a carbon atom with 4 different groups attached / Non-optically active substances do not have any carbon with 4 different groups attached. Enantiomers rotate (plane) polarised light in opposite directions. NCEA 2016 Optical Isomers Merit Question Question 1c: (i) Glycine, alanine, and serine are three amino acids shown below. Draw the 3-D structures of the enantiomers (optical isomers) of serine in the boxes below. NCEA 2016 Optical Isomers Merit

Question Question 1c: (ii) Which amino acid below which does NOT display optical isomerism: Explain your answer Glycine. It does NOT have a chiral C, i.e. it needs four different groups around the central C atom, glycine only has three Reaction types (1) Organic Reactions C H I Cl Br

O N Substitution reactions are characterized by replacement of an atom or group (Y) by another atom or group (Z). Aside from these groups, the number of bonds does not change. Addition reactions increase the number of bonds to the Carbon chain by bonding additional atoms, usually at the expense of one or more double bonds. Elimination reactions decrease the number of single bonds by removing atoms and new double bonds are often formed. Reaction types (2) C

H I Cl Br O N Organic Reactions Acid Base Reactions involve the transfer of a proton from the acid to the base which produces a salt Oxidation reactions involve a lost of electrons from the organic molecule or a gain of oxygen. An oxidant such as dichromate or permanganate is used to make a diol (2 OH) or dilute acid to make an alcohol (1 OH)

Polymerisation reactions join monomers together to form a polymer. Condensation polymerisation removes a small molecule and joins monomers Organic Reactions Alkene reactions Addition Reactions Organic Reactions Alkenes are unsaturated molecules, that is that not every carbon atom has the maximum amount of atoms bonded to it because it has one or more double bonds. If another atom is added to an alkene the double bond can be broken down to a single bond and the available site can be occupied by another atom. This reaction is known as an addition reaction. This reaction has a lower activation energy requirement than substitution, that is it requires less energy to break a double bond than break a C-H bond, therefore it can proceed easier than a substitution reaction. Break this bond

Two places to bond atoms to Markovnikovs Rule Organic Reactions Markovnikovs rule - sometimes called the rich get richer rule The major product is the one in which the H atom of HBr attaches to the C atom with the most H atoms already Asymmetric molecules such as HCl and H2O can also be added to alkenes resulting in the formation of two possible products. H H H H H3C H C C C H C C + HBr H H Br Minor H H

or H3C H C H C + HBr H 1-bromopropane H H H H C

C C H H Br H 2bromopropane Major Reaction types (Addition to unsymmetrical Alkenes) Organic Reactions C H Br or Cl Addition reactions increase the number of bonds to the Carbon chain by bonding

additional atoms, usually at the expense of one or more double bonds. HBr Or HCl minor major Ba Kn ck ow gro le un dg d e Testing for alkanes and alkenes Alkenes and alkynes undergo addition reactions - this means they can undergo addition of a halogen across the double (or triple) bond to form a di-haloalkane (or tetrahaloalkane). The common test for an unsaturated hydrocarbon is therefore the rapid decolourisation of an orange solution of bromine. This occurs both in the presence or absence of

sunlight (c.f. reaction of alkanes). CH3CH=CH2 + Br2 An alternative test to distinguish alkenes from alkanes is the reaction of alkenes with potassium permanganate. In acid solution the purple permanganate ion, MnO4, is reduced to colourless manganese ion, Mn2+, while in neutral solution it is reduced to brown manganese dioxide, MnO2. Alkanes have no reaction with potassium permanganate so the solution remains purple. 1,2-dibromopropane Oxidation reactions with alkenes Organic Reactions Alkenes can also undergo a oxidation reaction (this could also be classified as an addition reaction). The reagent is an oxidant, potassium permanganate (acidified) , MnO4-/H+, performed under reflux conditions.

The reaction creates a diol. Two hydroxyl groups join onto the carbons on either end of the broken double bond. Compare this to the addition reaction that which occurs with dilute acid added to an alkene. Only a single hydroxyl group is added to make an alcohol. Reaction types (Oxidation to Alkenes) Organic Reactions C H Oxidation reactions involve a lost of electrons from the organic molecule or a gain of oxygen. An oxidant such as dichromate or permanganate is used to

make a diol (2 OH) or dilute acid to make an alcohol (1 OH) O oxidant diol Dilute H2SO4 alcohol Addition Reactions 1. Hydrogenation Alkene + H2 Alkane Organic Reactions 2. Hydration Alkene + H2O Alcohol

3. Reaction with HCl Alkene + HCl Haloalkane 4. Halogenation (Bromine/Chlorine) Alkene + Halogen Haloalkane 5. Oxidation (oxidant) Alkene + Halogen Haloalkane Organic Reactions Alkene preparation Organic Reactions Haloalkane Reactions

Organic Reactions Elimination Reactions Elimination reactions decrease the number of single bonds by removing atoms and new double bonds are often formed. The Halogen atom is removed and a double bond forms between the two carbon atoms. Elimination of Haloalkanes is favoured when the solvent used is less polar eg. alcoholic (rather than aqueous) KOH. The reagent may be referred to as either ethanolic KOH, KOH / CH3CH2OH or OH- in alcohol. The reaction also occurs more favourably with tertiary haloalkanes rather than primary. Organic Reactions Elimination major and minor products Saytzeffs rule (poor get poorer)

When an elimination reaction occurs on a secondary haloalkane (with more than 3 carbons in the longest chain) then the H removed along with the halogen (Cl/Br) can come from either side. This produces 2 types of products; major or minor. This H and Br Or this H and Br Br But-2-ene Minor product as the H is taken from the Carbon with the most hydrogen atoms. Major product as the H is taken from the Carbon with

the least hydrogens atoms (can be cis or trans) Reaction types (Elimination of unsymmetrical Haloalkanes) Organic Reactions C H Br or Cl Elimination reactions decrease the number of single bonds by removing atoms and new double bonds are often formed. minor KOH alcoholic major

Organic Reactions Substitution Reactions Substitution reactions do not change the number of single bonds. The Halogen atom is removed and a hydroxyl (OH) group is substituted. Substitution of Haloalkanes is favoured when the solvent used is polar eg. aqueous (rather than alcoholic) KOH. The OH bonds with the same carbon that the halogen is removed from. A primary halogen will become a primary alcohol and a secondary halogen will become a secondary alcohol Reaction types (Substitution of Haloalkanes)

Organic Reactions C H Br or Cl O Substitution reactions are characterized by replacement of an atom or group (Y) by another atom or group (Z). Aside from these groups, the number of bonds does not change. KOH aqueous Haloalkane preparation Haloalkanes are formed when alkanes undergo a substitution reaction. Hydrogen atoms are substituted (repaced) by a group 17 halogen atom. Organic Reactions

For example, methane undergoes a series of substitution reactions with chlorine gas (Cl2) in the presence of ultraviolet light. H H C H Cl H + H H Cl C Cl

H Haloalkanes can also be formed by addition reactions of Alkenes + H Cl Organic Reactions Haloalkane preparation 2 Haloalkanes are relatively nonpolar overall (despite the polarity of the C-X bond) and are insoluble in water. A monohaloalkane eg. 2-bromopropane can be formed by a) substitution of propane using Br2. (forming two products, the bromoalkane and HBr) b) addition of HBr to propene (forming only one product) c) substitution of the OH on an alcohol using eg. PCl3, PCl5,SOCl2 or conc HCl/ZnCl2 Organic Reactions Alcohol reactions

2 Alcohol reactions Substitution by nucleophillic substitution Organic Reactions H H H H O C C C H

H H SOCl H PCl5 Oxidation using acidified potassium permanganate or acidified dichromate 1Alcohol + oxidant H H H H O C C

C H H H warmed + KMnO4 H aldehyde carboxyllic acid H H H C

C H H + H 2O O C O Lose 2 Hydrogen (as water) and add a double bonded OxygenHto end carbon Elimination using conc. Sulfuric acid (catalyst) Alcohol H + H2SO4 H H H

O C C C H H H heated Alkene + H 2O H H H

+H2SO4 C H C H C H H Alcohol Reactions - Elimination Elimination using conc. Sulfuric acid (catalyst) Organic Reactions Alcohol H

+ H2SO4 heated H H H O C C C H H Alkene H H

H H +H2SO4 C H C H C H +H2O H Elimination reactions occur when the hydroxyl group (OH) plus a hydrogen from an adjacent (beside) carbon atom is removed. The OH and the H removed form a water molecule. The two carbons with the OH and H taken off join to form a double

one. A concentrated sulphuric acid is used as the reagent. This type of elimination reaction is also known as a dehydration reaction because water is removed. Elimination major and minor products Organic Reactions (poor get poorer) When an elimination reaction occurs on a asymmetrical secondary alcohol (with more than 3 carbons in the longest chain) then the H removed along with the OH can come from either side. This produces 2 types of products; major or minor. This H and OH Or this H and OH But-2-ene

Minor product as the H is taken from the Carbon with the most hydrogen atoms. Major product as the H is taken from the Carbon with the least hydrogens atoms (can be cis or trans) Reaction types (Elimination in a Secondary Alcohol) Organic Reactions C H O Elimination reactions decrease the number of single bonds by removing atoms and new double bonds are often formed. minor

Concentrated H2SO4 major Organic Reactions Alcohol Reactions - Oxidation Aldehydes must always be prepared from Primary alcohols. Primary alcohols can be oxidized by mild oxidizing agents, such as potassium dichromate (K2Cr2O7), or potassium permanganate (KMnO4)to yield aldehydes. Alcohol reactions Oxidation in primary alcohols Organic Reactions Oxidation - using acidified KMnO4 or acidified K2Cr2O7

The type of product formed depends on whether the alcohol used in the oxidation reaction is primary or secondary. Conditions are warm only with use of distillation to collect evaporated aldehyde as it has a lower boiling point than the alcohol (which has hydrogen bonding) Primary alcohols are oxidised to form aldehydes, which are then easily oxidised further to form carboxylic acids. Cr2O72/H+ CH3CH2OH ethanol Cr2O72/H+ ethanal

ethanoic acid When using acidified dichromate in this redox reaction, the Cr2O72 is reduced to Cr3+, and the colour changes from orange to green. This colour change was the basis for the chemical reaction in the old blow in the bag breathalyser test. When using acidified permanganate in this redox reaction, the MnO4 is reduced to Mn2+, and the colour changes from purple to colourless. Reaction types (Oxidation in Primary Alcohols) Organic Reactions C H Oxidation reactions involve a lost of electrons from the organic molecule or a gain of oxygen. An oxidant such as dichromate or permanganate is used to make a aldehyde O

aldehyde Primary alcohol cold Oxidant MnO4reflux Oxidant MnO4- Carboxylic acid Organic Reactions Distilation A primary alcohol is oxidised to an aldehyde. The aldehyde can be further oxidised by exactly the same reagent to a carboxylic acid, so it is important to remove it from the reaction vessel immediately. This is possible as the aldehyde has a much lower boiling point

than both the alcohol and carboxylic acid. The reaction is performed in a distillation flask above the boiling point of the aldehyde and below the boiling point of the other compounds and the aldehyde is allowed to distil off as it is formed. Alcohol reactions Oxidation in secondary alcohols Oxidation - using acidified KMnO4 or acidified K2Cr2O7 Organic Reactions Secondary alcohols are oxidised to form ketones which do not oxidise further Tertiary alcohols do not oxidise Organic Reactions Reflux An Aldehydes can be further oxidised to produce Carboxylic

acid. (the Carboxylic acid can also be prepared directly from the primary alcohol). The process requires the use of reflux apparatus. The aldehyde (or alcohol solution) is heated until it forms the carboxylic acid but the water jacket condenser prevents the aldehyde escaping as vapour which has a lower boiling point than the Carboxylic acid that has Hydrogen bonding. Reaction types (Oxidation in Secondary Alcohols) H Organic Reactions C O Oxidation reactions involve a lost of

electrons from the organic molecule or a gain of oxygen. An oxidant such as dichromate or permanganate is used to make a ketone Oxidant Secondary alcohol ketone Alcohol reactions - Substitution Organic Reactions Substitution - of the OH by a Cl to form a chloroalkane. This substitution removes the hydroxl group (plus one hydrogen to form water) and replaces the two bonding sites on the carbons with a H and Cl (from HCl). This is called a nucleophilic substitution as the Br is attracted to the nucleus of the carbon atom The haloalkane formed is nonpolar and insoluble in the aqueous solution so

forms a cloudy emulsion that separates out as two layers. Alcohol reactions - Substitution For secondary alcohols - solution slowly goes cloudy as the chloroalkane slowly forms and separates. conc HCl/ZnCl2 Organic Reactions For primary alcohols - reaction is so slow a single layer containing unreacted alcohol remains. Substitution of alcohols can also be carried out using PCl5, PCl3 and SOCl2. Lucas Reagent and substitution Organic Tests Lucas' reagent is a solution of zinc chloride in concentrated HCl, used to classify alcohols of low molecular weight. The reaction is a substitution in which the chlorine

replaces the hydroxyl (OH) group. The reagent dissolves the alcohol, removing the OH group, forming a carbocation. The speed of this reaction is proportional to the energy required to form the carbocation, so tertiary alcohols react quickly, while smaller, less substituted, alcohols react more slowly. The cloudiness observed is caused by the carbocation immediately reacting with the chloride ion creating an insoluble chloroalkane. We can use these to identify whether an alcohol is primary, secondary or tertiary The time taken for turbidity to appear is a measure of the reactivity of the class of alcohol with Lucas reagent, and this is used to differentiate between the three classes of alcohols: * no visible reaction: primary alcohol * solution turns cloudy in 3-5 minutes: secondary alcohol * solution turns cloudy immediately: tertiary alcohol Organic Tests Lucas Test observations Substitution - of the OH (hydroxyl) by a Cl to form a chloroalkane. This substitution is faster for tertiary alcohols than for secondary, and slowest for primary alcohols. It is the basis of the Lucas test for distinguishing between small molecules of primary, secondary and tertiary alcohols. The reagent used is conc HCl and anhydrous ZnCl2 (called Lucas Reagent), and it is shaken with alcohol in a test tube at room temperature. The haloalkane formed is nonpolar and insoluble in the aqueous solution so forms a cloudy emulsion that separates out as two

layers. For tertiary alcohols - solution rapidly goes cloudy and two layers form. Organic Reactions Alcohol formation LiAlH4 Alcohols are formed by a) reduction of aldehydes and carboxylic acids (forming primary alcohols) and ketones (forming secondary alcohols). The reagent used is NaBH4 or LiAlH4. b) (nucleophilic) substitution of OH for X on haloalkanes c) addition of H2O to alkenes. NCEA 2013 Alcohol Tests Merit Question Question 3a:(ii) Describe how you could distinguish between the alcohols in (i) above,

using chemical tests on the alcohols and / or their oxidation products. Butan-1-ol is oxidised using permanganate / acidified dichromate, EITHER forming an aldehyde which can be identified using Tollens, silver mirror forms / Benedicts or Fehlings solution. OR forms brick red precipitate / forming a carboxylic acid, which can be identified turning (moist) blue litmus paper red. Butan-2-ol is oxidised to a ketone with permanganate / acidified dichromate, but this does not give a positive test using Tollens or Benedicts. Methyl propan-2-ol does not react with oxidising agents, permanganate remains purple / dichromate remains orange. Lucas test may be accepted with correct explanation. (anhydrous) ZnCl2 and conc HCl Solution goes cloudy / layers form: Tertiary in seconds :Secondary in minutes :Primary in hours / no reaction. Amine reactions Organic Reactions Amines behave like ammonia due to a lone pair of e- proton acceptors (i.e. bases) Like ammonia itself, water soluble amines form alkaline solutions. They react with water by proton transfer to form OH- ions. This means aqueous solutions of amines

turn litmus blue. RNH2 + H2O RNH3+ + OHAmines also react with acids to form salts. CH3NH2 + HCl CH3NH3+ Claminomethane methyl ammonium chloride The formation of an ionic salt increases the solubility of the amine in acidic solutions (compared to their solubility in water). This change in solubility can be used to separate amines from other organic compounds. The formation of the salt also results in the disappearance of the obnoxious smell of the amine, which explains why lemon juice is often provided with fish meals. Amines are made by the substitution reaction between NH3 and haloalkanes, but the reaction is carried out using alcohol as a solvent rather than water. Amine reactions Organic Reactions Behave like ammonia due to a lone pair of eproton acceptors (i.e. bases) reaction with water RNH2 + H2O RNH3+ + OHAmine + water amine salt + hydroxide This reaction can occur in

solution, or in the air as vapours given off solutions of both chemicals meet and combine to form a smoke. This smoke is made of the salt in solid form. CH3NH2 + H2O CH3NH3+ + OHaminomethane methylammonium hydroxide reaction with acid to form salts RNH2 + HCl RNH3+ + ClCH3NH2 + HCl CH3NH3+ + Claminomethane hydrochloric methylammonium chloride acid Organic Reactions Amine reactions Act as ligands, forming complex ions with transition metal ions.

e.g. Cu2+(aq) + 4NH3(aq) [Cu(NH3)4]2+(aq) pale blue deep blue tetraamminecopper(II) complex ion Cu2+(aq) + 4CH3NH2(aq) [Cu(CH3NH2)4]2+(aq) pale blue deep blue tetra aminomethanecopper(II) Nucleophiles (due to lone pair of e-) They attack the + carbon of a haloalkane. Amine (ammonium) ion + Carboxylic ion reactions Organic Reactions Naming salts. The amine ion effectively becomes an ammonium ion and acts as the cation in forming the ionic salt. The organic group attached to it becomes a branch and is named as such. i.e. CH3NH3+ becomes methyl ammonium The carboxylic ion becomes the anion and takes on the suffix

anoate. i.e CH3COO- becomes methanoate Therefore a salt made of the 2 ions CH3NH3+ CH3COO- is called methyl ammonium methanoate Organic Reactions Amine Formation Substitution reactions are characterized by replacement of an atom or group (Y) by another atom or group (Z). Aside from these groups, the number of bonds does not change. 2 Organic Reactions Organic Reactions Carboxylic Acid Reactions

2 Carboxylic Acid Reactions - Acid/base Organic Reactions Carboxylic acids act as a weak acid by partially dissociating and neutralising bases: For example RCOOH + NaOH RCOONa + H2O acid + base salt + water Carboxylic Acid Reactions Acid/base Organic Reactions Carboxylic Acids Acid + Base Carboxylic salt + NH4+ Carboxylic ion Acid-Base reaction

NH3 Carboxylic acid also have similar reactions to other acids carboxylic acid + carbonate carboxylic salt + water + carbon dioxide carboxylic acid + metal carboxylic salt + hydrogen gas carboxylic acid + oxide carboxylic salt + water Carboxylic Acid Reactions Acid/base Organic Reactions Carboxylic Acids are Weak Acids proton donors in water H2O React with magnesium to give hydrogen gas (a useful test) CH3COOH + Mg Mg(CH3COO)2 + H2(g) React with calcium carbonate to give CO2(g) (a useful test) CH3COOH + CaCO3 Ca(CH3COO)2 + CO2(g) + H2O H3 O +

Carboxylic Acid Reactions - Substitution Organic Reactions C H O Cl Substitution reactions are characterized by replacement of an atom or group (Y) by another atom or group (Z). Aside from these groups, the number of bonds does not change. PCl5 Or SOCl This reaction takes place under reflux conditions

Carboxylic Acid Reactions - Substitution Substitution reaction to form acid chlorides Using PCl3, PCl5 or SOCl2 (not conc HCl), carboxylic acids undergo a substitution reaction RCOCl. Organic Reactions O H3C C OH ethanoic acid O PCl5 H3C C

Cl ethanoyl chloride The acid chloride is named using the name of the parent alkane, but changing the final -e to -oyl chloride. The acid chloride formed reacts violently with water to produce the corresponding carboxylic acid. It is for this reason that conc HCl cannot be used to make an acid chloride as the concentrated acid consists of at least 60% water. Carboxylic Acid Reactions - Esterification Organic Reactions Esterification is a condensation reaction that combines a carboxylic acid and an alcohol, where a water molecule is removed. The carboxylic acid and alcohol are refluxed with concentrated sulphuric acid. After reflux, sodium carbonate is added to neutralise any excess acid and anhydrous magnesium sulfate

MgSO4 is added to remove water. Because of the volatility of esters, they are then readily separated from the reaction mixture by fractional distillation. Carboxylic Acid Reactions - Esterification C H O Condensation (or dehydration) reactions are a type of elimination reaction where a molecule of water is removed) in esterification OH is removed from alcohol and O from a carboxylic acid and they are joined to form an ester Organic Reactions Primary alcohol

Carboxylic acid Ester This reaction takes place under reflux conditions Organic Reactions Carboxylic Acid Preparation Carboxylic acid can be prepared directly from a primary alcohol under reflux conditions or through an intermediate group of aldehydes if distillation is used. Common oxidants can be dichromate or permanganate. Carboxylic Acid Preparation Organic Reactions

1. Oxidation of Alkenes Using hot acidified manganate (VII). The diol first formed splits and the two fragments oxidise further to form carboxylic acids. 2-butene butan-2,3-diol the reaction continues . ethanoic acid Carboxylic Acid Preparation Organic Reactions 2. Oxidation of a 1o alcohol 1o alcohol + [O] aldehyde + [O] carboxylic acid (see under alcohols or aldehydes) 3. Hydrolysis of Esters (eg fats and oils) H2O

4. Hydrolysis of an Acid Chloride H2O Aldehyde/Ketone Reactions - Reduction Organic Reactions Reduction of Aldehydes and Ketones- NaBH4 (sodium borohydride)- reduce aldehydes to primary alcohols and ketones to secondary alcohols. This is considered a reduction reaction because the amount of Hydrogen increases. Sometimes LiAlH4 (lithium aluminium hydride) can also be used as a reductant Aldehyde/Ketone Reactions - Reduction Organic Reactions Reduction of Aldehydes and Ketones with NaBH4 In this Reduction reaction we are breaking a C-O bond and replacing it with a C-H bond. This is what helps us classify the reaction as a reduction. Note that we also form an O-H bond. In order to make the alcohol, the oxygen needs to pick up a proton (H+) (called pronation) from either water or acid that is added after the reaction is complete.

Primary alcohol Aldehyde NaBH4 (Or LiAlH4) ketone Secondary alcohol C H O Aldehyde/ Ketone Reactions Organic Tests Oxidation of aldehydes Aldehydes are readily oxidised by even mild oxidising agents such as Ag+ and Cu 2+, which are too weak to oxidise alcohols. Like alcohols they are also oxidised by acidified potassium dichromate and acidified potassium permanganate.

In contrast, ketones are not oxidised, and this means that they can readily be distinguished by observing the reaction with an oxidising agent. Tollens test If Tollens reagent (a colourless solution [Ag(NH3)2]+ ) is heated with an aldehyde a redox reaction occurs, which produces a silver mirror on the inner surface of the test tube. The aldehyde is oxidised to a carboxylic acid. The reduction half-equation is Ag+(aq) + e Ag(s) If Tollens reagent is heated with a ketone or an alcohol no reaction occurs. This means there would be no observed colour change and no formation of a silver mirror. Aldehyde/Ketone Reactions Organic Tests Tests to distinguish between Aldehydes and Ketones Benedict's test - Benedicts reagent is an alkaline solution containing a copper(II) citrate complex ion. When Benedicts solution is heated with an aldehyde the Cu2+ complex ion acts as an oxidising agent, and the blue

complex of Cu2+ is reduced to a brick red precipitate of Cu2O. When heated with a ketone (or an alcohol), Benedicts solution does not react and remains blue. Fehling's test - Fehling's solution is an alkaline solution containing a deep blue complex ion of Cu2+ (copper(II) tartrate complex ion). It is also reduced to red Cu2O when heated with an aldehyde, but has no reaction with ketones (or alcohols). Fehlings Solution Positive (aldehyde) Negative (ketone) Aldehyde/Ketone Reactions Redox Identify whether each reactant is a ketone or aldehyde and the expected observations in each of the following reactions. In some cases there will be no reaction.

(a) Methanal is heated with Tollens reagent. Aldehyde so Silver mirror forms around the outside of the test tube. (aldehyde oxidises to a Carboxylic acid) Organic Tests (b) Hexanan-2-one is heated with Benedicts reagent. Ketone so no reaction (c) Propanone is reacted with acidified potassium permanganate. Ketone so no reaction (d) 2-methylpropanal is heated with Cr2O72/H+. Aldehyde so solution reduces from Orange dichromate into green chromium ions (Cr3+). (aldehyde oxidises to a Carboxylic acid) (e) 3-methylpentanal is reacted with Benedicts reagent. Aldehyde so blue solution turns orange. (aldehyde oxidises to a Carboxylic acid) (f) Butanone is heated with Tollens reagent. Ketone so no reaction. Aldehyde/Ketone Reactions Organic Tests We can use these to identify whether the molecule is an Aldehyde or Ketone Aldehyde Ketone

Potassium permanganate Oxidises into carboxylic acid Purple to colourless No reaction Tollens reagent [Ag(NH3)2]+ Oxidise aldehydes (but not alcohols) Silver mirror forms No reaction Benedicts solution Cu2+ ions Oxidises aldehydes (but not alcohols) to form Cu+ ions Red/brown ppt forms

No reaction Organic Reactions Acid Chloride reactions Choice of chlorinating agent. By choosing the correct chlorinating agent, the products will be easier to separate by fractional distillation. e.g. If PCl5 was used to chlorinate butanoic acid, the products butanoyl chloride (B.P. 102oC) and phosphorous oxychloride POCl3 (B.P. 103oC) would be difficult to separate Condensation Condensation (or dehydration) reactions are a type of elimination reaction where a molecule of water is removed) in esterification OH is removed from alcohol and O from a carboxylic acid and they are joined to form an ester

Substitution reactions are characterized by replacement of an atom or group (Y) by another atom or group (Z). Aside from these groups, the number of bonds does not change. Organic Reactions Acid Chloride reactions - Substitution Reactivity The C-Cl bond is highly polar. The carbon is + and is readily attacked by nucleophiles causing substitution of the Cl. For this reason, acyl chlorides are useful for producing many chemicals. Addition of water to acyl chlorides results in a vigorous exothermic reaction. RCOCl + H2O RCOOH + HCl Substitution reactions are characterized by replacement of an atom or group (Y) by another atom or group (Z). Aside from these groups, the number of bonds does not change. Acid Chloride Carboxylic Acid Acid Chloride reactions - Esterification Organic Reactions

React readily with alcohols to produce esters RCOCl + ROH RCOOR + HCl The acid chloride is dropped into pure alcohol, (in fume cupboard, because HCl(g) is produced). Reaction is fast, yield is high, no heat or catalyst required. C H O Cl Primary alcohol Acid Chloride Ester Acid Chloride reactions Substitution with ammonia

Organic Reactions React readily with Ammonia to form Amides Acyl chlorides react readily with ammonia to form 1o amides. RCOCl + NH3 RCONH2 + HCl ammonia 1o amide C H O Cl N As HCl is produced in the reaction it reacts with unreacted NH3 HCl + NH3 NH4Cl Adding these two we find the overall reaction. RCOCl + 2NH3 RCONH2 + acyl chloride ammonia

1 o amide NH4Cl + - Acid Chloride Primary Amide Organic Reactions Acid Chloride reactions Substitution with amines Acyl chlorides react readily with 1o amines to produce 2o amides RCOCl + RNH2 RCONHR + HCl acyl chloride amine 2o amide C H O As HCl is produced in the reaction it reacts with unreacted amine. HCl + RNH2 RNH3Cl Adding these two reactions together we find the overall reaction.

RCOCl + 2RNH2 RCONHR + RNH3+ Clacyl chloride 2o amide Cl N + Amine Acid Chloride Secondary Amide Organic Reactions Acid Chloride preparation By nucleophilic substitution reactions. The carboxylic acid is heated under anhydrous conditions with a chlorinating agent such as: sulphur dichloride oxide SOCl2 (thionyl chloride)

phosphorus pentachloride PCl5 phosphorus trichloride PCl3 RCOOH + SOCl2 RCOCl + SO2(g) + HCl RCOOH + PCl5 RCOCl + POCl3 + HCl 3RCOOH + PCl3 3RCOCl + H3PO3 Amide Reactions - Hydrolysis Hydrolysis Reactions of Amides Acid hydrolysis produces the carboxylic C H O N acid and ammonium ions. You distinguish an amide from an amine by RCONH2 + H3O+ RCOOH + NH4+ adding NaOH. Only the amide releases NH . 3 Organic Reactions amide + +

Basic hydrolysis produces the carboylate ion and ammonia amide RCONH2 + OH RCOO1- + NH3 1- - - Organic Reactions Amide Preparation Hydrolysis Substitution reactions are characterized by replacement of an atom or group (Y) by another atom or group (Z). Aside from these groups, the number of bonds does not change. Hydrolysis reactions involve water as a reactant and becomes part of the reaction product. Organic Reactions Amide Preparation

Reaction of carboxylic acids with ammonia Step 1: React carboxylic acid with ammonia to form ammonium salt. RCOOH + NH3 RCOONH4 Step 2: Thermal decomposition of ammonium salt to give amide and water. The salt is heated and water is slowly distilled off as it forms. RCOONH4 RCONH2 + H2O Reaction of Acyl chloride with ammonia 1o amine, 2o amine produces 1o, 2o, 3o amides respectively. Reaction of Ester with ammonia 1o amine, 2o amine produces 1o, 2o, 3o amides respectively. NCEA 2013 Reactions Merit Question Question 2a: For the following conversions, identify the reagent required, and state the type of reaction occurring. (i) Pentan-2-one is converted to pentan-2-ol. Reagent: NaBH4 / LiAlH4 Type of reaction reduction / redox

(ii) Butan-2-ol is converted to a mixture of but-1-ene and but-2-ene. Reagent: conc H2SO4 / conc H3PO4 / Al2O3 Type of reaction elimination / dehydration / condensation NCEA 2013 Reactions (Alcohol) Excellence Question Question 2a: (ii) Butan-2-ol is converted to a mixture of but-1-ene and but-2-ene. Reagent: conc H2SO4 / conc H3PO4 / Al2O3 Type of reaction elimination / dehydration / condensation Discuss the reaction occurring in (ii) above, with reference to the structures of the organic reactant and products. Explanation: An elimination reaction occurs because the molecule has changed from saturated to unsaturated / a (C=C) double bond forms. Because water is removed / H and OH have been removed (from adjacent C atoms). The but-2-ene is the major product / but-1-ene is the minor product. A mixture of products is formed, because the two carbons adjacent to the carbonbearing OH have different numbers of H atoms attached / it is asymmetric. (Zaitsevs (Saytzeffs) rule the major product has the more substituted double bond)

NCEA 2013 Reactions (Alcohol) Excellence Question Question 2b: Discuss the laboratory procedures used to convert butan-1-ol into butanal, and butan-1-ol into butanoic acid. In each discussion, you should: outline the process for each conversion state and justify the type of reaction occurring identify the reagents used, and explain any observations made. Aldehyde (Butanal) is obtained by distillation of butan-1-ol with acidified (potassium) dichromate / (acidified potassium) permanganate solution. (Distillation) is used because the aldehyde has a lower boiling point (than butan-1-ol and the carboxylic acid formed) / to prevent it from being oxidised further. (Both) reactions are oxidationreduction because butan-1-ol has lost electrons/lost hydrogen/gained oxygen/oxidation number (of C) has increased. Carboxylic acid (butanoic acid) is obtained by reacting a mixture of butan-1-ol with acidified potassium dichromate solution (under reflux conditions) until all of the reactant has been converted to butanoic acid. Observations: orange Cr2O72 to green /, purple MnO4 to colourless / aldehyde condensed in the condenser.

NCEA 2013 Reactions (Alcohol) Merit Question Question 3a: (i) Three alcohol compounds are listed below. methylpropan-2-ol butan-1-ol butan-2-ol Compare and contrast the structures of the compounds above. The three alcohols are (structural) isomers / they have the same molecular formula but different structural formula. Methyl propan-2-ol is a tertiary alcohol Butan-2-ol is a secondary alcohol Butan-1-ol is a primary alcohol NCEA 2013 Reactions (Acid Chlorides) Question 3c: When ammonia reacts with Excellence Question two products are formed. Complete the equation below by naming compounds or drawing the structure.

Hydrogen chloride / HCl / ammonium chloride / NH4Cl Name: 3 methyl butanoyl chloride. NCEA 2014 Reactions (Alcohol) Excellence Question Question 1(b) When butan-2-ol undergoes a reaction with concentrated H2SO4, three possible organic products form, which are isomers of each other. Answer:The minor product is (i) Draw the three isomers formed during this reaction. (ii) Which of the three isomers from part (i) will be formed but-1-ene. Saytzeffs rule: the minor in the smallest amount? product will have the least substituted double bond OR Answer: Saytzeffs rule is explained. Eg: the minor product is formed by the removal of the OH group and a hydrogen atom

is removed from the carbon adjacent to the C-OH that has the most hydrogens NCEA 2014 Reactions (Haloalkanes) Achieved Question Question 2(b) Instructions for the preparation of 2-chloro-2-methylpropane are given below. Read the instructions carefully and answer the questions that follow. 1. Shake 10 mL of 2-methylpropan-2-ol with 30 mL of concentrated hydrochloric acid in a separating funnel for 10 minutes. 2. Run off the bottom acid layer and discard it. Add saturated sodium hydrogen carbonate to the organic product. Shake, releasing the tap every few seconds to relieve the pressure. 3. Run off the bottom aqueous layer and discard it. Transfer into a conical flask and add some anhydrous sodium sulfate, and stir thoroughly. 4. Transfer the organic product into a round-bottom flask, and collect the fraction boiling within 2oC of the boiling point of 2-chloro-2-methylpropane. (i) Explain why the solution of sodium hydrogen carbonate is added in instruction 2. Name the gas produced in this step. Answer:

Gas = Carbon dioxide / CO2 NaHCO3 is used to remove any remaining acid mixed with the liquid product. NCEA 2014 Reactions (Haloalkanes) Excellence Question Question 2(b) (ii) Explain why anhydrous sodium sulfate is added in instruction 3. Answer: Na2SO4 is added to remove any remaining water mixed with the liquid product. Question 2(b) (iii v) Name the process used in instruction 4 to purify the organic product. Identify which piece of the equipment that a student would use to perform this process from the diagrams below. Answer: Fractional Distillation. Equipment 1. The purpose of the process is to purify the chemical / remove impurities / separate product. This is achieved by separating liquids according to their boiling points. Chemicals are boiled then condensed / liquid-gas then gas-liquid. The fraction at the desired boiling point is kept / other fractions are discarded. NCEA 2015 Reactions (Haloalkanes) Question 1(c) (ii) : Elaborate on the reactions occurring when each of the haloalkane isomers from (c)(i) reacts with KOH in alcohol.

In your answer you should include: the identification of ALL organic products formed an explanation of the type of reaction taking place reasons for the formation of any major and minor products. Excellence Question Answer: ClCH2CH2CH2CH3 H2C=CHCH2CH3 H3CCH(Cl) CH2CH3 two possibilities: 1. Minor H2C=CHCH2CH3 but-1-ene 2. Major H3CCH=CHCH3 cis but-2-ene and trans but-2-ene (in equal quantities). H3C CCl(CH3)CH3 C(CH3)(CH3)=CH2 All reactions are ELIMINATION reactions as the Cl functional group and the hydrogen atom from the adjacent carbon atoms are removed. (The molecule changes from saturated to unsaturated). The secondary haloalkane produces major and minor products because the molecule is asymmetric OR it has two adjacent C atoms with different numbers of H atoms attached. The major product is formed when the H atom is removed from the adjacent C atom with the fewest H atoms attached, OR the major product has the most substituted double bond. NCEA 2016 Reactions (Aldehydes and Ketones)

Merit Question Question 2a: (i) What reagent can be used to reduce aldehydes and ketones? Sodium borohydride / NaBH4 (accept LiAlH4) Question 2a: (ii) For the reduction of pentanal and pentan-2-one, draw the structure of the organic product formed in each case. Identify the functional group of each product formed. CH3CH2CH2CH2CH2OH Pentanal will produce a primary alcohol / pentan-1-ol. Pentan-2-one will produce a

secondary alcohol / pentan-2-ol. Ester Reactions - Esterification (Acid) Carboxylic Acid + alcohol Ester + water Heating and H2SO4 Organic Reactions H H H O H C C

H H H C H H C H H C H H

C C O O H H H H H H C C H

H O C O H H C H H C H C H H2O H C

H H Ester Reactions hydrolysis (Alkaline) Ester + sodium hydroxide Organic Reactions H H H C C H H Alcohol + sodium carboxylic acid

H O C + NaOH O H C H H C H H C H

H H C H C H Butyl propanoate H H H C H H C C

H + H H H C C H H O C H

Na O H butanol O Sodium propanoate Revert back to original alcohol and add a Na atom to the carboxylic acid Triglycerides Glycerol + 3 long carboxylic acids (fatty acids) Organic Reactions GLYCEROL H O

H H H C C C H O H H propan,-1,2,3-triol O

H g l y c e r o l triglyceride Fatty acid Fatty acid Fatty acid Triglycerides are naturally found in animal fats and seed and nut oils Saponification Triglycerides heated with NaOH produce soap + glycerol Organic Reactions

Alkaline hydrolysis of fats and oils, producing soaps Fats and oils are triesters e.g. glycerol tristearate a saturated fat found in many animal and vegetable fats such as tallow (animal fat). OR Alkaline hydrolysis of fats and oils, producing soaps Organic Reactions Hydrolysis of fats or oils with ethanolic aqueous sodium hydroxide produces glycerol and the sodium salt of the fatty acid. NCEA 2013 Ester reactions (PART ONE) Merit Question Question 1d: Give the structures and names of the products of the reactions below.

These reactions are carried out by heating in either: dilute hydrochloric acid solution, or dilute sodium hydroxide solution. NCEA 2013 Ester reactions - (PART TWO) Excellence Question Question 1d: Compare and contrast the reactions below. In your answer, you should include the type of reaction(s) taking place. The ester link is hydrolysed in both acid and basic conditions. Both produce an alcohol. Acidic hydrolysis produces an acid and basic hydrolysis produces a base or salt / following hydrolysis in sodium hydroxide, an acid-base reaction occurs to form the sodium salt and water. (No further reaction occurs in acid.) NCEA 2014 Ester Reactions Merit Question Question 1(c): (i) The triglyceride below is shown in condensed form. Circle a functional

group on the diagram above and give its name. Ester group (ii) Compare and contrast the reaction of the triglyceride when it undergoes both acidic and basic hydrolysis. In your answer you should include: drawings of condensed structures of the organic products any reagents and conditions required for the reaction to proceed. Answer: Both acidic and basic hydrolysis produce the same alcohol propan-1,2,3-triol. In addition, they both require heat / reflux In contrast, acidic hydrolysis requires H2O / H+ or HCl(aq) and produces the carboxylic acid, whereas basic hydrolysis requires H2O / OH or NaOH(aq) and produces the carboxylate ion/salt. NCEA 2015 Ester Reactions Merit Question

Question 3(a): (a) A triglyceride has the following structure: (i) Circle one of the alkene groups in the triglyceride molecule. This triglyceride is described as unsaturated. (ii) Describe a chemical test that can be used to show that the molecule is unsaturated. Give any observations, and state the type of reaction occurring. Answer: Bromine water rapidly decolourised from red or orange to colourless in an addition reaction. OR Acidified permanganate rapidly decolourised from purple to colourless in a redox or oxidation or reduction reaction. NCEA 2015 Ester Reactions Merit Question Question 3(a): (iii) Draw the structural formulae of the organic products formed by hydrolysis of this triglyceride using aqueous sodium hydroxide.: Answer:

NCEA 2015 Ester Reactions Question 3(a): (iv) Explain why the equipment to the right is used for hydrolysis of the triglyceride. Answer: Reflux - Increases the rate of reaction; (Condensing) prevents volatile chemicals from being lost to the environment, (The mixture refluxed to increase reaction rate without loss of product through evaporation). Merit Question NCEA 2016 Ester Reactions Merit Question Question 3c: A triglyceride found in olive oil has the following structurebelow: (i) Put a circle around one of the ester groups in the triglyceride molecule shown above. (ii) Draw the structural formulae of the products produced by the hydrolysis of this

triglyceride in basic conditions, using aqueous sodium hydroxide, NaOH. Condensation polymerisation Organic Reactions Polyesters Condensation reactions involve the elimination of water. Polymerisation involves smaller units called monomers joining together to form larger molecules or chains called polymers. There are two main types of condensation polymers Polyesters - the monomers consist of a di carboxylic acid ( a COOH at each end) and a diol (an OH at each end) . These monomers join together at each end to form an ester bond. The CA and the alcohol then continue joining in repeating patterns. Polyamide the monomers consist

of an amide and a di carboxylic acid. Polyamides Organic Reactions Polyamides A carboxyl group (carbon with a double bonded oxygen such as carboxylic acid) and a amino group (with a NH2 attached to the carbon chain such as an amide or amine) can react together to form an amide or peptide link (-CONH) through condensation polymerisation as a water molecule is released to form each link. e.g. Nylon-6,6 Preparation: Condensation

polymerisation of a diamine and a dicarboxylic acid Polyamide Products A polyamide is a polymer containing monomers of amides joined by peptide bonds. They can occur both naturally and artificially, examples being proteins, such as wool and silk, and can be made artificially through step-growth polymerization or solid-phase synthesis, examples being nylons, aramids, and sodium poly(aspartate). Polyamides are commonly used in textiles, automotives, carpet and sportswear due to their extreme durability and strength Polyesters These are formed by repeated condensation of a di-acid and a di-alcohol. e.g. Preparation of Terylene H Organic Reactions H

O H H C C H H O H O + O C

O 1,2-ethanediol Repeated condensation reactions at either end produces the polymer Terylene. [CH2CH2OOCPhCOO-]n C H H C C H O O O

H O H C H O H H C O C H H

O O C C benzene-1,4-dicarboxylic acid O O H O H C H O H

+ H O H NCEA 2015 polymerisation Achieved Question Question 2(c): A form of the polymer nylon can be made from the two monomers below. 1,6-diaminohexane Sebacoyl chloride (decanedioyl dichloride) (i) draw the repeating unit of the polymer formed if these two monomers are used. Answer: NCEA 2015 Polymerisation

Achieved Question Question 2(c): Consider the formation of this form of nylon in a laboratory. (ii) Describe the type of reaction occurring, and explain why this reaction results in a polymer. Answer: This is condensation or substitution (polymerisation), whereby the two monomers are joined together and a small molecule (HCl(g)) is released. Each monomer is di-functional or has a reactive site at each end (allowing polymerisation to be ongoing.) (iii) Explain why sebacoyl chloride is dissolved in a non-polar organic solvent rather than in water. Answer: The sebacoyl chloride (as an acyl chloride) reacts vigorously with water forming the carboxylic acid, (however, it does not react with the non-polar solvent.) NCEA 2015 Polymerisation Question 2(c): (iv) Elaborate on the reaction that will occur if a dilute aqueous solution of acid is mixed with the newly formed polymer. Answer: Dilute acid will cause hydrolysis of the amide linkage. The products formed would be (di)ammonium salt or +H3N(CH2)6NH3+

and the (di)oic acid. HOOC(CH2)8COOH (Names not required) Excellence Question Amino Acids Amino acids Amino acids have both the basic amino, NH2, and acidic carboxylic acid, CO2H, groups. In acidic solutions, the basic NH2 group is protonated to form a positively charged amino acid. H O H2N C R C

H2N OH General formula C H C H H H O H2N C OH

aminoethanoic acid N O C CH3 O C Amino Acid OH 2-aminopropanoic acid Amino Acids Amino Acids Most Amino Acids form optical isomers (or enantiomers) because they have a chiral carbon with four different groups off it. Our

bodies only use one type of optical isomer for each amino acid. Proteins Amino Acids Made from condensation polymerisation of amino acids. Two simple amino acids are glycine and alanine. Alanine has optical isomers. H N H O H C H N C H

O H O H H H C C C O H H H glycine

alanine Human protein is made from about 20 different amino acids. peptide link: The linking bond between two amino acids. CONH- (same as an amide link) Peptide bond Amino Acids Peptide bond Proteins Amino Acids In solution the carboxylic acid can donate a proton to the amine, and form a zwitterion. (zwei = 2 in German) There are two separate charges on the ion. NCEA 2013 Amino Acids Merit

Question Question 2d: Peptides are formed when amino acids combine. (i) In the boxes below, show two possible dipeptides that can be formed by combining the amino acids: NCEA 2016 Amino Acids Question 1c: (iii) Draw the two possible dipeptides formed from the amino acids glycine and alanine. . Excellence Question Merit Question NCEA 2016 Amino Acids Question 1c: (iv) Name the type of reaction that occurred when the dipeptides formed in (iii) above. Explain your Answer Condensation. Two larger molecules are joined together with

the elimination of a smaller molecule. (v) Draw the products of an acidic hydrolysis for ONE of the dipeptides from (iii) above. Explain why these products are formed. Excellence Question Acidic hydrolysis leaves COOH group intact and NH2 group becomes protonated to form NH3+. H3N+CH(CH3)COOH H3N+CH2COOH NCEA 2015 Reaction Scheme Excellence Question Question 3(b): Complete the following reaction scheme by drawing the

structural formulae of the organic compounds A to E, and identifying reagents 1 to 5. NCEA 2015 Reaction Scheme Excellence Question Structures A = CH3CH2CH2NH2 B = CH3CH2CH2OH C = CH3CH2CHO OR CH3CH2COOH D = CH3CH2COOCH2CH3 E = CH3CH2COCl Reagents 1 = NaOH(aq) OR KOH(aq) 2 = Cr2O72 / H+ or MnO4 / H+ 3 = NaBH4 OR LiAlH4

4 (i) = CH3CH2OH or ethanol 4 (ii) = concentrated H2SO4 5 = NH3 (alcoholic / gas / conc).. NCEA 2014 Reaction Scheme Question 3(a): Propene can be reacted with water in the presence of acid to form a major product (A) and a minor product (B). A is oxidised to form product C. B is oxidised to form product D. When D is reacted with SOCl2, it forms product E. When D is reacted with alcohol B, it forms an ester G. When D is reacted with alcohol A, it forms ester H, which is an isomer of G. When E is reacted with alcoholic ammonia, it forms product F. When E is reacted with water, it forms product D.

Excellence Question NCEA 2014 Reaction Scheme A = Propan-2-ol Excellence Question B = Propan-1-ol C = Propanone D = Propanoic acid E = Propanoyl chloride H = Methyl ethyl propanoate (not required) F = Propanamide

G = Propyl propanoate NCEA 2013 Reaction Scheme SOCl Question 3(a): Complete the following reaction scheme by drawing the structural formulae of the organic compounds B and C, and identifying reagent 1. Include any necessary conditions, needed to bring about the transformation from reactant A to the organic compound C, which is a base. Merit Question

(Accept PCl3, PCl5 or conc HCl / ZnCl2) NCEA 2016 Reaction Scheme Question 3a: Complete the following reaction scheme by drawing organic structures for S1 to S7, and identifying reagents 1 to 3. S1: CH3COOCH2CH2CH3 S2: CH3CH2CH2OH S3: CH3CH=CH2 S4: CH3CH2CH2Cl S5: CH3CH(Cl)CH3 S6: CH3COCl S7: CH3CONHCH2CH2CH3 Reagent 1 = H2O / H (dilute acid) Reagent 2 = conc. H+ (H2SO4 or H3PO4) + Excellence Question

NCEA 2016 Reaction Scheme Excellence Question Question 3b: Draw a reaction scheme to show the conversion of butan-1-ol to butan-2-one. You should include any relevant reagents, conditions required, and the structures of all organic substances involved. Step 1: Butan-1-ol to but-1-ene. Dehydration reaction (elimination reaction) using conc H2SO4. Step 2: But-1-ene to butan-2-ol. Hydration reaction (addition reaction) using dil. H2SO4 (H+/ H2O) Step 3: Butan-2-ol (Major product) to butan-2-one. Oxidation reaction of secondary alcohol to from a ketone using Cr 2O72 / H+ under reflux. NCEA 2013 Distinguishing tests Merit Question

Question 1c: Draw the structural formulae of three different isomers of which show the following properties: Isomer 1 turns moist blue litmus paper red. Isomer 2 is an ester. Isomer 3 is a ketone. O CH3 CH2 C OH O O CH3 C HC O CH3 HO CH2 C CH3 O O CH2 CH3

NCEA 2013 Distinguishing tests Merit Question Question 2c: Devise a method for distinguishing between the three liquid compounds, butan-1-ol, butanoic acid, and butanoyl chloride, using only blue litmus paper and water. Explain each of the observations in your method, with reference to the structure of the organic compounds. Add to water then test with blue litmus paper The butan-1-ol will not react with water nor change the colour of the moistened litmus paper. The butanoic acid will change the moistened blue litmus paper to red. The butanoyl chloride will react violently with the water. Carboxylic acids react with water to form hydronium ions / equation CH3CH2CH2COOH + H2O CH3CH2CH2COO- + H3O+ Acyl chlorides react with water to form carboxylic acids and hydrogen chloride / equation CH CH CH COCl + H O CH CH CH COOH + HCl NCEA 2014 Distinguishing Tests Excellence

Question Question 2(a): (iv) Explain why the equipment to the right is used for hydrolysis of the triglyceride. (i) Aqueous solutions of propanamine and propanamide. Answer: Damp red litmus. Propanamine will change the colour of red litmus blue. Propanamide will not change the colour of red litmus. (ii) Propanone and propanal. Answer: Tollens reagent (Fehlings or Benedicts or Cr2O72 / H+ or MnO4 / H+). Propanal will form a silver mirror when warmed with Tollens reagent. Propanone will not react with Tollens reagent. (iii) Propanoyl chloride and propyl propanoate. Answer: Water. Propanoyl chloride will react violently with water. Propyl propanoate with not react with water / it will form layers. NCEA 2016 Distinguishing tests

Excellence Question Question 2b: Explain how you would identify each of the organic substances, A to D, from the table in (b)(i), using only moist litmus paper, water, and Benedicts solution. In your answer, you should include: a description of any tests carried out and any observations you would make equations to show the organic products formed, if applicable. A: Propan-1-amine. (1-propanamine) B: Propanal. C: Propanoyl chloride. D: Propan-2-one. (propanone) A: Propan-1-amine (a primary amine) CH3CH2CH2NH2 (propan-1-amine) will turn moist red litmus paper blue as it is basic. CH3CH2CH2NH2 + H2O CH3CH2CH2NH3+ + OH Water: Dissolves in water. Benedicts solution will stay blue as primary amines do not react with Benedicts reagent. NCEA 2016 Distinguishing tests Continued Excellence

Question B: Propanal (An aldehyde) Damp Litmus: No colour change. Water: Dissolves in water. Propanal will react with Benedicts reagent, with the blue solution forming a (copper mirror) / brick red precipitate. Propanoic acid is formed. CH3CH2CHO CH3CH2COOH C: Propanoyl chloride (An acyl chloride) Damp Litmus: Turn blue litmus red Water: Propanoyl chloride will react vigorously with water to produce propanoic acid and hydrogen chloride. CH3CH2COCl + H2O CH3CH2COOH + HCl Benedicts solution will stay blue as the acyl chloride does not react with the Benedicts, but instead reacts with the water present in the Benedicts solution. D: Propan-2-one (A ketone) CH3COCH3 (propan-2-one) Damp Litmus: No colour change. Water: Dissolves in water. Benedicts solution: No reaction, so stays blue. Reaction types Substitution reactions are characterized by replacement of an atom or group (Y) by another atom or group (Z). Aside from these groups, the number of bonds does not change.

Polymerisation reactions join monomers together to form a polymer. Condensation polymerisation removes a molecule of water (H from one monomer and OH from another) and joins the two ends of the monomers together Oxidation reactions involve a lost of electrons from the organic molecule or a gain of oxygen. An oxidant such as dichromate or permanganate is used. Condensation (or dehydration) reactions are a type of elimination reaction where a molecule of water is removed) in esterification OH is removed from alcohol and O from a carboxylic acid and they are joined to form an ester Addition reactions increase the number of bonds to the Carbon chain by bonding additional atoms, usually at the expense of one or more double bonds. Hydrolysis reactions involve water as a reactant and becomes part of the reaction product. Elimination reactions decrease the number of single bonds by removing atoms and new double bonds are often formed. Reduction reactions involve a gain of electrons from the organic molecule or a loss of oxygen. A reductant such as NaBH4 is used.

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