Syllabus

Syllabus

Syllabus

Syllabus

Carbonyls

Carbonyls

A carbonyl group can be identified within a compound by adding solid2,4 dinitrophenylhydrazine (NH2NHAr) to ethanol then adding H3PO4 oradding solid NH2NHAr to methanol then slowly add H2SO4. The Solution is known as brady’s reagentbrady’s reagent, and is added to the suspectedcarbonyl compound to give a orangeorange//yellowyellow ppt (red in fact sheets).

This strangely does not need to be knowndoes not need to be known for your A level.

Carbonyls

Aldehydes can be oxidised to carboxylic acids whereas ketonescannot. Hence certain chemical tests can be done with oxidisingagents to distinguish between aldehydes and ketones. One such testto distinguish whether our carbonyl is a ketone or an aldehyde is toadd alkaline ammoniacal silver nitrate solution (also known astollen’s reagent). In the solution. Ag+ ions react with OH- of aqueousammonia to produce a brown precipitate of Ag2O which is dissolvedon addition of an excess of aqueous ammonia to give [Ag(NH3)2]+. The silver ionssilver ions are reduced by aldehydes, themselvesforming a carboxylic acid.

Carbonyls

Below is a diagram showing the ammoniacal silver nitrate test which you need to knowneed to know along with another common test which you do do not not need to knowneed to know for this syllabus.

Another alternative test to the ammoniacal silver nitrate test which you do need to knowneed to know is fehlings solution, which has blue complex copper (II) ions in alkali. The Cu2+ ions are reduced to a red ppt of Cu2O if an aldehyde is present.

RCHO + 2Cu2+ + 4OH- RCOOH + Cu2O + 2H2O

Carbonyls

Carbonyls can be reduced to alcohols by reaction with LiAlH4 in dry dry

etherether then careful addition of watercareful addition of water. You can also use NaBH4 to do the same job. The equation and mechanism which you have to knowhave to know for such reactions are shown below.

CH3CHO 2[H] CH3CH2OH

Carbonyls

Jan 2004 edexcel

Carbonyls can react with cyanide ions to produce compounds knownas hydroxynitriles.

These used to be known as cyanohydrins.

The reaction isn't normally done using hydrogen cyanide itself, because this is an extremely poisonous gas.

Instead, the hydrogen cyanide is generated in in situsitu by mixing thecarbonyl with a solution of sodium or potassium cyanide in water, with a little sulphuric acid added (fact sheets say HCN and a trace ofKOH) The pH of the solution is buffered to between6-8 (m/s 6b Q3 jun 2003).

Carbonyls

..

Background material - Cyanide ions bond to hemoglobin

Cyanide is a poison. Cyanide bonds (irreversibly) to the site (Fe II) where oxygen usually bonds. You die of suffocation due to lack of oxygen. HCN is a gas that you can easily breathe into your lungs, hence is very dangerous to work with.

The reaction mechanism for the reaction of cyanide ions with carbonyl compounds is shown below. It is an example of a nucleophillic nucleophillic addition reactionaddition reaction and you have to know it.you have to know it.

Carbonyls

Mod 4 jan 2006 (old syllabus)

Carboxylic acids

To test to see whether an organic compound is a carboxylic acid or not we add PCl5. This will yield steamy whitewhite acidic fumes if a RCOOH group is present. To confirmconfirm we have a carboxylic acid and not just a alcohol, we add a carbonate/hydrogen carbonate to the suspected carboxylic acid. If the RCOOH group is present the limewater will go milky/cloudymilky/cloudy like the diagram below.

Finally carboxylic acids can react with alcohols to make esters.

The above reaction is reversible so can be used to make the alcoholand carboxylic acid from the ester. The above reactions equilibriumalso lies in favour of the ester.

Radioactive labelling shows that the C-O bond in the carboxylic acidbreaks rather than the O-H bond, so when working out what the esterlooks like, you take the OH group off the acid, and the hydrogen fromthe OH group of the alcohol, and join the RCO and OR such that theoxygen from the OR group bonds to the carbon of the RCO.

Esterification

The esterification reaction mechanism

This mechanism doesdoes not neednot need to be known for your A level.

Esterification - Question

a) Write an equation for the reaction of methanoic acid with propan-1-ol

b) What acid and alcohol make the ester propyl ethanoate

Esters

Esters have a fruity smell (some books say a glue like smell), and are in fact what give fruits their taste and smell. As such we use esters as flavourings.flavourings. Esters are also used as plasticisersplasticisers, solventssolvents and are used in perfumes.perfumes.

Esters can be hydrolysed using alkalis. The products of this reaction are a carboxylic salt (in blue) and an alcohol (in red). This reaction goes to completion. The mechanism does notdoes not need to be known.

Esters

Esters can be hydrolysed using acids. The products of this reaction are a carboxylic acid (in blue) and an alcohol (in red). This reaction is a reversible reaction, and is in fact the reaction we use to make the ester in the first place. The mechanism does notdoes not need to be known.

Esters

Esters - Questions

Write two equations one to show the acid hydrolysis of propyl methanoate, and one to show the alkaline hydrolysis of ethyl propanoate.

Fats and oils

Fats and oils are ester molecules that contain 3 ester linkages like the molecules below (the ester groups are highlighted in red). If the hydrocarbon chains making up the ester contain single bonds between the carbons, we say the ester is saturated (as each carbon is bonded to as many hydrogen’s as is possible).

The fats and oils found in plants and animals are estersesters made from carboxylic acids and alcohols. These fats can be hydrolysed to propan - 1,2,3- triol (glycerol) and various carboxylic acids known in biology as fatty acids. These fatty acids can have varying chain length and can be saturated or unsaturated.

Fats and oils

Mod 4 jun 2005 (old syllabus)

Animal fats can be hydrolysedhydrolysed using sodium hydroxidesodium hydroxide to give sodium salts of the fatty acidssodium salts of the fatty acids and glycerol.glycerol. The sodium salt is in fact what soap is made of.

Where R equals a long hydrocarbon chain of undefined length.Clearly soaps are carboxylic acid derivatives and when put into water the sodium and carboxylate ions break up and dissolve. The carboxylate ions then go on to bond to water and the hydrocarbon chain bonds to organic matter such as grease, hence the soap is able to bring grease and water together.

Soap

Biodiesel

Biodiesel refers to a non-petroleum-based diesel fuel consisting of long-chain alkyl (methyl, propyl or ethyl) esters.

Biodiesel is typically made by chemically reacting lipids such as vegetable oil and animal fats (tallow)) with alcohol. It can be used alone, or blended with conventional petro-diesel in unmodified diesel-engine vehicles.

Vegetable oils and animal fats are triglycerides composed of three chains of fatty acids bound by a glycerin molecule (see previous fats and oils slides).

In the conversion process triglyceride esters are turned into alkyl esters namely biodiesel using a catalyst of lye (NaOH) and an alcohol reagent, e.g. methanol, which yields methyl esters biodiesel. The methanol replaces the glycerin.

Acid chlorides

Acid chlorides are carboxylic acid derivatives. You can make them in the lab by reacting PCl5 with a carboxylic acid, although in industry they are made by reacting SOCl2 with a carboxylic acid.

Acid chlorides undergo nucleophillic addition-elimination reactions. For your A level you need to know the products of the reaction of an acid chloride with the organic molecules below. Note the other product in all of these reactions is HCl and all the reactions are carried out at room temperature.

Acid chlorides

Acid chlorides - Questions

It will form a secondary amide

It will react faster / reaction can occur at room temperature

Phosphorous pentachloride PCl5

Acid chlorides - Questions

Write an equation for the reaction of ethanoyl chloride with ethanamine

CH3COCl + CH3CH2NH2 CH3CONHCH2CH3 + HCl

Acid chlorides undergo nucleophillic addition-elimination reactions. These reactions all react via a similar mechanism to the one shown below, which shows an acid chloride reacting with ammonia to make an amide.

Acid chloride reaction mechanisms - ammonia

Acid chlorides undergo nucleophillic addition-elimination reactions. These reactions all react via a similar mechanism to the one shown below, which shows an acid chloride reacting with water to make a carboxylic acid.

Acid chloride reaction mechanisms - water

Acid chlorides undergo nucleophillic addition-elimination reactions. These reactions all react via a similar mechanism to the one shown below, which shows an acid chloride reacting an alcohol to make an ester.

Acid chloride reaction mechanisms - alcohols

Acid chloride reaction mechanisms – primary amines

Acid chlorides undergo nucleophillic addition-elimination reactions. These reactions all react via a similar mechanism to the one shown below, which shows an acid chloride reacting a primary amine to make a secondary amide.

Mod 4 jun 2006

If you took two ethanoic acid molecules and removed a molecule of water between them, you would get the acid anhydride, ethanoic anhydride (old name: acetic anhydride).

You can actually make ethanoic anhydride by dehydrating ethanoic acid, but it is normally made in a more efficient, round-about way.

Acid anhydrides

Naming acid anhydrides is easy. You just take the name of the parent acid, and replace the word "acid" by "anhydride". "Anhydride" simply means "without water".Therefore ethanoic acid forms ethanoic anhydride; propanoic acid forms propanoic anhydride, and so on.

Ethanoic anhydride is a colourless liquid, smelling strongly of vinegar (ethanoic acid). The smell is because ethanoic anhydride reacts with water vapour in the air (and moisture in your nose) to produce ethanoic acid again.

Ethanoic anhydride can't be said to dissolve in water because it reacts with it to give ethanoic acid. There is no such thing as an aqueous solution of ethanoic anhydride. Ethanoic anhydride boils at 140°C. This is because it is a fairly big polar molecule and so has both van der Waals dispersion forces and dipole-dipole attractions. It doesn't however, form hydrogen bonds. That means that its boiling point isn't as high as a carboxylic acid of similar size. For example, pentanoic acid (the most similarly sized acid) boils at.

Acid anhydrides

Mod 4 jun 2006

It is easier to think of acid anhydrides as if they were a sort of modified acyl chloride than to try to learn about them from scratch. If you Compare the structure of an acid anhydride with that of an acyl chloride - looking carefully at the colour-coded diagram below.

In the reactions of ethanoic anhydride, the red group at the bottom always stays intact, just like the chlorine atom in the acyl chloride.The usual reaction of an acyl chloride is replacement of the chlorine by something else.With an acid anhydride, the reaction is slower, but the only essential difference is that instead of hydrogen chloride being produced as the other product, you get ethanoic acid instead.

Acid anhydrides

Acid anhydrides undergo nucleophillic addition-elimination reactions. For your A level you need to know the products of the reaction of an acid anhydride with the organic molecules below. Note the other product in all of these reactions is ethanoic acid, and all the reactions are carried out at room temperature. You will notice the organic products of these reactions are the same as for acid chloridesthe same as for acid chlorides. The only difference is the reactions are sloweronly difference is the reactions are slower and the other product is the other product is ethanoic acidethanoic acid not hydrochloric acid.

Acid anhydrides

Mod 4 jan 2006

Aspirin is synthesised industrially by the reaction below

Synthesis of aspirin

The aspirin can be made by reacting salicylic acid (2-hydroxybenzoic acid) with ethanoyl chloride or acetic anhydride

acetic anhydride is preferred over ethanoyl chloride for the manufacture of the aspirin as;

Ethanoic anhydride is cheaper cheaper than ethanoyl chloride.

Ethanoic anhydride is safersafer to use than ethanoyl chloride. It is less less corrosivecorrosive and not so readily hydrolysednot so readily hydrolysed (its reaction with water is slower).

Ethanoic anhydride doesn't produce dangerousdoesn't produce dangerous (corrosive and poisonous) fumes of hydrogen chloridehydrogen chloride.

Synthesis of aspirin

Give one advantage of the use of propanoyl chloride instead of propanoic acid in the laboratory preparation of methyl propanoate from methanol.

faster/not reversible/bigger yield/purer product/no(acid) (catalyst) required (1)

Give one advantage of the use of propanoic anhydride instead of propanoyl chloride in the industrial manufacture of methyl propanoate from methanol. anhydride less easily hydrolysed or reaction less violent/exothermicno (corrosive) (HCl) fumes formed, or safer or less toxic/dangerousexpense of acid chloride or anhydride cheaperAny one (1)

(2 marks)

Mod 4 jun 2006

Amines possess the NH2 functional group

Aliphatic methylamine, ethylamine, dimethylamine

Aromatic NH2 group is attached directly to the benzene ring (phenylamine)

Amines

Nomenclature Named after the groups surrounding the amine functional group

C2H5NH2 ethylamine

(CH3)2NH dimethylamine

(CH3)3N trimethylamine

C6H5NH2 phenylamine (aniline)

Amines

Reagent - ammonia (in excess)(in excess)Conditions – in ethanolic ethanolic solution underunder pressurepressureType of reaction - nucleophillic substitution

Equation C2H5Br + 2NH3 (alc) C2H5NH2 + NH4Br

C2H5Br + NH3 (alc) C2H5NH2 + HBr

HBr + NH3 (alc) NH4Brnotes The equation shows two ammonia molecules.

The second one ensures that a salt is not formed.Mechanism - this needs to be known for your AS

Preparation of amines from haloalkanes

Why use excess ammonia? - A large excess ammonia ensures that further substitution doesn’t take place (see below)

Problem - Amines are also nucleophiles (lone pair on N) and can attack another molecule of halogenoalkane to produce a 2° amine. This too is a nucleophille and can react further producing a 3° amine and, eventually an ionic quarternary ammonium salt.

C2H5NH2 + C2H5Br HBr + (C2H5)2NH diethylamine, a 2° amine

(C2H5)2NH + C2H5Br HBr + (C2H5)3N triethylamine, a 3° amine

(C2H5)3N + C2H5Br (C2H5)4N+ Br¯ tetraethylammonium bromide

a quaternary (4°) saltThe quatenary salt formed here can be used as cationic surfactants in

fabric softening e.g. [CH3(CH2)17]2N+(CH3)2 Cl¯

Preparation of amines from haloalkanes

reaction mechanism of ammonia with a haloalkane

Below is the reaction mechanism for the reaction of a haloalkane withammonia. This needs to be known for your A level.

reaction mechanism of a primary amine with a haloalkane

Below is the reaction mechanism for the reaction of a haloalkane withA primary amine. This needs to be known for your A level.

Mod 4 jan 2006

Amines can also be prepared from the reduction of nitriles.

This Is done using LiAlH4 in dry ether and then careful additionwater, or of NaBH4 in water

Nitriles can also be reduced to amines by reacting with Ni and H2

Equation

CH3CN + 4[H] CH3CH2NH2

Preparation of amines from nitriles

Mod 4 jun 2006

Mod 4 jun 2006

Bases The lone pair on the nitrogen atom makes amines basic;

RNH2 + H+ RNH3+ a proton acceptor

Strength - depends on the availability of the lone pair and its ability to

pick up protons, the greater the electron density on the N, the better

it can pick up protons. This is affected by the groups attached to thenitrogen

Amines

Amino acids

Amino acids have the general structure of NH2CH(R)COOH Where R can represent a lot of different groups (as shown below ), the simplest being a hydrogen atom to give the amino acid glycine. Below are the structures of two specific amino acids glutamine and tryptophan.

Apart from glycine, amino acids have an assymmetric carbon, which means each amino acid exists as a pair of enantiomers, each able to rotate plane polarised monochromatic light in different directions. Therefore when writing the names of any amino acids (except glycine), you have to put a D or an L in front of the name to say which way it rotates plane polarised monochromatic light.

Amino acids

In solution amino acids exist in their zwitterion structures, hence glycine looks like the molecule below. This is because the acid dissociates in solution. The lone pair of electrons on the amine group is able to form a dative covalent bond with the hydrogen ion. This also of course creates an ion with a full positive and negative charge at each end of the molecule. This of course means the hydration enthalpy is much greater than it would have been if the carboxylic acid had not dissociated into hydrogen ions. It would have formed hydrogen bonds with the water of a much lower hydration enthalpy, so would have been less thermodynamically stable.

Amino acids

Mod 4 jan 2006

Mod 4 jun 2005

Mod 4 jun 2007

Amino acids can act as buffers, that is to say they can resist changes in pH when reacting with small amounts of acid or alkali as shown below. Below I have used the zwitterion structures and I have written ionic equations. What you write in the exam depends on how the question is asked.

Amino acids

Amino acids - Question

Alanine is the simplest amino acid to possess an assymmetric carbon atom, and hence show optical activity. It has the structure shown below. Write equations to show it reacting with sodium hydroxide and hydrochloric acid.

Mod 4 jun 2007

Proteins

Proteins are made when amino acids form peptide linkages as is illustrated in the diagram below. This sequence continues to give a protein consisting of millions of amino acids.

Mod 4 jun 2006

Mod 4 jun 2007

Proteins

Within the long protein chains there are regions in which the chains are organised into regular structures known as alpha-helices (alpha-helixes) and beta-pleated sheets. These are the secondary structures in proteins.These secondary structures are held together by hydrogen bonds. These form as shown in the diagram between one of the lone pairs on an oxygen atom and the hydrogen attached to a nitrogen atom:

In an alpha-helix, the protein chain is coiled like a loosely-coiled spring. The "alpha" means that if you look down the length of the spring, the coiling is happening in a clockwise direction as it goes away fromThe next diagram shows how the alpha-helix is held together by hydrogen bonds. This is a very simplified diagram, missing out lots of atoms. We'll talk it through in some detail after you have had a look at it.

Proteins

Proteins

The protein chains can then fold to give structures like those below

Proteins

Protein chains can be hydrolysed to yield the amino acids which made them in the first place. In the reaction water acts as a nucleophille and attacks the carbonyl carbon to yield amino acids.

A mixture of amino acids can be separated using chromatography. for simplicity we'll assume that you know the mixture can only possibly contain five of the common amino acids. A small drop of the mixture is placed on the base line of the thin layer plate, and similar small spots of the known amino acids are placed alongside it. The plate is then stood in a suitable solvent and left to develop. In the diagram, the mixture is M, and the known amino acids are labelled 1 to 5.The left-hand diagram shows the plate after the solvent front has almost reached the top. The spots are still invisible. The second diagram shows what it might look like after spraying with ninhydrin (a locating agent).

Chromatography amino acids

There is no need to measure the Rf values because you can easily compare the spots in the mixture with those of the known amino acids, both from their positions, and their colours.In this example, the mixture contains the amino acids labelled 1, 4 and 5. If the mixture contained amino acids other than the ones used for comparison there would be spots in the mixture which didn't match those from the known amino acids. You would then re-run the experiment using other amino acids for comparison.

Chromatography amino acids

AN EXAMPLE OF ADDITION POLYMERISATIONAlkenes can undergo addition polymerisation whereby the pi bond of the double bond breaks, and the electrons from the bond can be used to form bonds between the molecules. This results in very long chain molecules known as polymers which it should be noted are alkanes, and like alkanes are un-reactive.

Polymers - animation

Alkenes can undergo addition polymerisation whereby the pi bond of the double bond breaks, and the electrons from the bond can be used to form bonds between the molecules. This results in very long chain molecules known as polymers which it should be noted are alkanes, and like alkanes are un-reactive.

Polymers

Polymers

With a polymer like polypropene the methyl groups can be arranged in very different ways along the chain as shown on the diagram below,

For the following polymers work out the monomers (the starting alkene) that they are derived from.

Question - spotting the monomer

Question - spotting the monomer

For the following polymers work out the monomers that they are derived from

Draw a representative length of the molecule of Poly-2-methylpropene, showing three repeating units.

Question

Draw the repeating unit of polytetrafluoroethene.

Question

Mod 4 jun 2006

Condensation polymers

Carboxylic acids react with alcohols to make esters but you can also make polyester if you react a diaciddiacid with a diol,diol, or react a molecule that has both an alcohol group and a carboxylic acid group.both an alcohol group and a carboxylic acid group.

a) Draw the polymer showing the repeating unit for the reaction of ethandioc acid with butan1,4-diol

b) Draw the polymer showing the repeating unit for the reaction of

HOOC(CH2)4COOH + HOC6H4OH

Question - Condensation polymers

Amines can react with carboxylic acids, and more importantly for the course that your following, with acid chlorides to make amides. Which, similar to acids with alcohols making polyesters, can make polyamides if you use a diamine and a diacid chloride, or a molecule with an acid group one end and an amine on the other end. Notice HCl is also made in the reaction.

Condensation polymers

Question - Polymers

a) Draw the polymer showing the repeating unit for the reaction of ethandioyl chloride with propan1,3-diamine

b) Draw the polymer showing the repeating unit for the reaction of

ClOC(CH2)6COCl + H2NC6H4NH2

Mod 4 jan 2006

Condensation polymers - Polyesters (terylene)

Reagents terephthalic acid HOOC-C6H4-COOHethane-1,2-diol HOCH2CH2OH

Equation nHOCH2CH2OH + nHOOC(C6H4)COOH -[OCH2CH2OOC(C6H4)CO]n- + nH2O

Product poly(ethylene terephthalate) ‘Terylene’, ‘Dacron’

Repeat unit —[-OCH2CH2OOC(C6H4)CO-]n—

Eliminated water

Reaction esterification

Properties contain an ester link that can be broken down by hydrolysis, hence is biodegradable

Uses fabrics

Condensation polymers - Polyamides (nylon-6,6)

Reagents hexanedioic acid HOOC(CH2)4COOHhexane-1,6-diamine H2N(CH2)6NH2

Equation nHOOC(CH2)4COOH + nH2N(CH2)6NH2 -[NH(CH2)6NHOC(CH2)4CO]n- + nH2O

Product Nylon-6,6

Repeat unit —[-NH(CH2)6NHOC(CH2)4CO-]n—

Eliminated water

Mechanism addition-elimination

Properties contain a peptide (or amide) link that can be broken down by hydrolysis hence is also biodegradable Uses fibres and ropes

Condensation polymers - Polyamides kevlar

Reagents 1,4-benzenedicarbonyl chloride ClOC(C6H4)COCl1,4-diaminobenzene H2N(C6H4)NH2

Equation nHOOC(C6H4)COOH + H2N(C6H4)NH2 -[NH(C6H4)NHOC(C6H4)CO]n- + nH2O

Product kevlar

Repeat unit —[-NH(C6H4)NHOC(C6H4)CO-]n—

Eliminated HCl

Mechanism addition-elimination

Properties contain a peptide (or amide) link that can be broken down by hydrolysis hence is also biodegradable Uses bullet proof vests

One of the wonderful properties of polymers is that they are chemically un-reactive. This means they are good for storing liquids like acids in, or for water pipes. However it is also one of their drawbacks as it means they are non-biodegradable. The reason why most polymers are non-biodegradable is because they are hydrocarbons such as polyethene or polypropene. This means it does not mix with water which means bacteria do not have access to the polymer, and even if they did there is no polarisation within the molecule for the bacteria to attack. The bonds are also strong which means they won’t react with oxygen.

Disposal of Polymers

Disposal of Polymers

Polyesters and polyamides on the other hand are polarised, therefore these polymers can be broken down by a hydrolysis reaction.

Mod 4 jun 2005

Disposal of Polymers

Polymers can be disposed of in many different ways. Each of the following methods has advantages and disadvantages

Landfill - Waste polymers are disposed of in landfill sites which is a cheap and easy method of disposal (advantage). This uses up valuable land (disadvantage), and suitable sites often fill up quickly.

Disposal of Polymers

Incineration - Polymers release a lot of heat energy when they burn. This energy can be used to heat homes or generate electricity (advantage). But there are problems with incineration. Carbon dioxide is produced, which adds to global warming. Toxic gases are also produced (disadvantage), unless the polymers are incinerated at high temperatures.

Recycling - Many polymers can be recycled. This reduces disposal problems (advantage) and the amount of crude oil used (advantage). But first the different polymers must be separated from each other. This can be difficult and expensive (disadvantage).

Fedir Kiskin Y13 2007 Organic Reactions

Consider the organic reaction scheme depicted on the previous slide. Find all the reagents/products represented by the letters A-O as well as a-e. State which of the compounds A-O exhibit optical isomerism.

Fedir Kiskin Y13 2007 Organic Reactions

Question AEA 2005

Answer AEA 2005

Question Draw the structures of compounds A ,B,E,F,G.

Answers

The structures of compounds A ,B,E,F,G.

Give the structural formula to show clearly the organic productformed from each of the following mixtures. If you consider noreaction occurs, you should state “no reaction”.

(i) 1-bromobutane with KOH in water (ii) 1-bromobutane with KOH in

alcohol

(iii) propanal with hydrogen cyanide (iv) 1-bromopropane with potassium cyanide

(v) propan-1-ol with ammoniacal (vi) propanone with silver nitrate ammoniacal

silver nitrate

Question

Answer

Farhan Shafi, Mukur Ghosh Y13 2007

Using the organic reaction scheme below, find all the products represented by letters A-M, as well as reagents, represented by letters a-c

Farhan Shafi, Mukur Ghosh Y13 2007

Fedir Kiskin Y13 2007

Compound A has the empirical formula CHO. In a titration, 5.22 g of A reacts exactly with 60 cm3 of a 1.5 moldm-3 solution of NaOH.

Reaction of the trans-isomer of A with a diol B forms a polymeric compound C which contains 56.5 % of carbon and 5.9 % of hydrogen by mass.

Calculate the empirical formula of C. Deduce structural formulae for compounds A and B and draw the repeating unit of the polymer.

Fedir Kiskin Solution

Fedir Kiskin Solution

It can therefore be deduced that compound B is butan-1,4-diol. The repeating unit of polyester C is:

From molecule A create molecule J, using the following reagents: H2O, NaOH, Dry ether, K2Cr2O7 LiAlH4 HCl H2SO4 Br2 Mg NH3 H2 Ni And using these steps:

Nikhil Patel and Rupesh Patel 2007

Nikhil Patel and Rupesh Patel 2007

Shahrouz Irvani Y13 2007

By looking at the following reaction scheme work out all products and reagents represented by the letters.

Answer Shahrouz Irvani Y13 2007

Cengiz and Dulal 2007 Yr13

Cengzong is used in the manufacturing of De-Odorants, it is a smelling agent. From Ethene, and using the list of Reagents below, create Cengzong, You have the use of any ordinary equipment you would find in a laboratory.

Cengiz and Dulal answer 2007 Yr13