Module 6 – Organic chemistry and analysis

TLC Chromatography

TLC: Thin Layer Chromatography is quick and inexpensive. Indicates how many components there are in mixture.  Phase: Stationary phase is solid adsorbent, usually silica. Stationary phase lies on TLC place, usually glass or plastic. Mobile phase is liquid solvent. ...

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Gas Chromatography

Gas Chromatography: GC MS enables products to be identified- by separating the components in a mixture and identify them by comparing with a database.  GC MS used in forensics, environmental analysis and airport security.  Number of products = number of peaks....

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NMR (Nuclear Magnetic Resonance) Spectroscopy

NMR: Nuclear magnetic resonance spectroscopy to analyse organic compounds. Nuclei of atoms absorbs magnetic field and radio frequency radiation, absorption measured by NMR. Frequency required for resonance proportional to magnetic field strength.  NMR used in...

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Carbon- 13 NMR Spectroscopy

C-13 NMR: Carbon- 13 NMR spectrum tells us… number of different carbon environments from number of peaks AND types of carbon environments from chemical shift values. Remember carbon as no splitting.  Chemical Environment: Carbon atoms bonded to different atoms...

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Proton NMR Spectroscopy

Proton NMR: Proton NMR spectrum tells us… 1) Number of different proton environments from number of peaks. 2) Types of proton environment from chemical shift values.  3) Relative number of proton in each environment given from integration traces/ ratio numbers of...

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Combined Techniques

Mass spec- molecular ion peak m/z to give Mr, fragment ions to identify parts of ion.  Cl can be Mr 35 or 37. Br can be Mr 79 or 81.

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Summary of Qualitative Analysis of Organic

Must learn these.  This is qualitative analysis.  Testing Phenol: Phenols acidic so can be tested using pH indicator paper. However phenols not as acidic as carboxylic acid and do not react with sodium carbonate.  Or can add bromine at room temperature...

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Esters

An ester is a carboxylic acid derivative.  Naming Ester: Put alcohol part first and then acid.  Ester commonly used for perfumes or flavourings as they have a fruity smell.  1) Esterification: Esterification is reaction of an alcohol with carboxylic acid to form a...

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Acyl Chloride

Acyl chloride is a carboxylic acid derivative.  Don’t forget the HCl when reacting with acyl chlorides.  1) Preparing Acyl Chloride: Carboxylic acid and SOCl2 thionyl chloride. Produces gases SO2 and HCl. Carry out in fume cupboard as products harmful.  Reactions...

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Amines

Amine: Amines are organic compounds, derived from ammonia NH3 where hydrogen atoms in ammonia have been replaced by a group.  Classifying Amines: Can get primary amine where one carbon atom attached to nitrogen (instead of hydrogen so leaves NH2). Secondary NH and...

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Reactions of Amines

1) Bases: Amines act as bases (so react with acids to from salts) due to lone pair of electrons on nitrogen accepting a proton. This forms a dative covalent bond between lone pair of electrons on N and the proton- forming an ammonium ion.  2) Salt Formation: Since...

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Preparation of Amines

3) Formation of Primary Amines: Aliphatic. 1) Salt Formation: Ammonia has lone pair of electrons on nitrogen so ammonia acts as nucleophile. Substitution reaction of haloalkane and ammonia, forming ammonium salt. 2) Amine Formation: Ammonium salt reacted with aqueous...

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Amino Acids

Amino Acids: An amino acid is an organic compound containing both basic amine, NH2, and acidic carboxylic acid COOH.  α- Amino Acids: Body has 20 amino acids, all of which are α- amino acids where amine group attached to α carbon atom- the second carbon atom next to...

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Reactions with Amino Acid

1) Reaction of Amine Group: Amine group in amino acids is basic and reacts with acids to form salts, in same way as amine does.  Reaction of Carboxylic Acids Group in Amino Acid…  2) Reaction of Carboxylic Acid Group with Aqueous Alkali: Amino acid reacts with...

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Amides and Chirality

Amides: Amides are products of reactions of acyl chlorides with ammonia/ amines.  Stereoisomerism: Remember stereoisomerism are compounds with same structural formula but different arrangement of atoms in space. Types of stereoisomerism are optical isomerism and E/ Z...

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Benzene

Benzene: Benzene is C6H6. Classed as an aromatic hydrocarbon or an arene. Two ways to draw benzene. Questions may use either, even though right one is misleading.  Joined double benzene ring has 10 carbons and not 12.  Physical Properties: Benzene is colourless,...

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Condensation Polymers

Addition Polymerisation: AS alkenes form polymers by addition polymerisation. Monomer of addition polymerisation will contain C=C-. Double bond breaks (pi bond breaks) in polymer and is replaced by single bond. In monomer double bond should be at either side. Imagine...

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Electrophilic Substitution Reactions of Benzene

Electrophilic Substitution: Benzene and its derivatives react with an electrophile which replaces a hydrogen atom on benzene.  1) Nitration of Benzene: Benzene reacts with nitric acid to form nitrobenzene in electrophilic substitution. Reaction catalysed by conc....

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Polyester

Polyester and polyamides used as fibres in clothing.  Polyesters: To form polyester, monomers joined together by ester linkages in a long chain. Polyesters can be made from one monomer OR two monomers…  When a polymer made from one monomer. The OH and COOH must be...

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Phenol

Phenols: Phenols contain a hydroxyl, -OH, directly bonded to an aromatic ring. Simplest member called phenol C6H5OH, same name as the group. Another example is 2- hydroxybenzoic acid below.  Aromatic Alcohol: Remember an alcohol is –OH bonded to carbon chain. An...

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Polyamides

Polyamides: Polyamides are condensation polymers when monomers joined together by amide linkages in long chain. Can be made from one monomer or two monomers…  3) Polyamides Made from One Monomer: - Polyamides made from one monomer containing either carboxylic acid...

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Directing Groups

Activation: A group present in reactant that activates the ring, so aromatic ring reacts more readily with electrophiles.  Deactivation: A group present in reactant that deactivates the ring, so aromatic ring reacts less readily with electrophiles.  Activation and...

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Hydrolysing Condensation Polymers

Hydrolysing: Condensation polymers can be hydrolysed using hot aqueous alkali e.g. sodium hydroxide OR hot dilute aqueous acid e.g. HCl.  Wherever there is an amide or ester bond, can break it apart and forms products either side of it. Add water on.  5) Hydrolysing...

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Carbonyl Compounds

Aldehyde: C= O or carbonyl group at the end. Written as CHO. Suffix –al.  Ketones: C= O or carbonyl group in middle. Written as CO. Suffix –one. Carbonyl group needs to be numbered, unlike aldehyde- which always in position 1.  Octanal- suffix starts with vowel, so...

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Carbon- Carbon Bond Formation

Formation of Nitriles: Nitrile group is –CN.  1) Haloalkanes to Nitriles: Haloalkanes reacted with sodium or potassium cyanide NaCN/ KCN in ethanol. In this reaction length of carbon chain increased. This is an example of nucleophilic substitution.  2) Aldehydes/...

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Identifying Aldehydes and Ketones

2, 4- DNP: A solution of 2,4- dinitrophenylhydrazine is used to detect presence of carbonyl functional group in aldehydes and ketones. If present, a yellow/ orange precipitate called 2,4- dinitrophenylhydrazone produced.  Brady’s Reagent: In practical’s, 2,4- DNP...

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Further Practical Techniques

Filtration under Reduced Pressure: Need Buchner flask, Buchner funnel, pressure tubing, filter paper and vacuum pump. This separates solid product from liquid.  Process: Connect tube from vacuum pump to Buchner flask. Fit Buchner funnel to flask using Buchner rubber...

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Carboxylic Acids

Carboxyl Group: Carboxyl group in carboxylic acid.  Uses: Carboxylic acids found in medicines and vinegar.  Naming: Methanoic acid HCOOH is simplest. As suffix starts with vowel, shorten butane to butan.  Solubility of Carboxylic Acids: - Polar C=O bond and O-H...

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Further Synthetic Routes

Important to identify all functional groups correctly on starting and target molecule.  If two functional groups on compound, need to write reactions that change one functional group and then write reactions that change the other functional group, independent of one...

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Carboxylic Acids Derivatives

Carboxylic Acid Derivatives: A derivative of carboxylic acid is a compound that can be hydrolysed to form the parent carboxylic acid. Esters, acyl chlorides, acid anhydrides and amides are derivatives of carboxylic acid. All carboxylic acid derivatives contain acyl...

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