27- amines, amino acids and polymers Flashcards
What is an amine?
Organic compounds derived from ammonia in which one or more of the H atoms in ammonia have been replaced by a carbon chain or ring.
How can amines act as bases?
They have a lone pair of electrons on the nitrogen atom so can accept a proton. When this happens, a dative covalent bond is formed between a lone pair of electrons on the nitrogen atom and the proton.
What happens when an amine reacts with an acid?
They neutralise acids to make salts as they’re a base.
How are primary amines formed?
Ammonia has a lone pair of electrons on the nitrogen atom which allows ammonia to act as a nucleophile in a substitution reaction with a haloalkane. The product of this reaction is an ammonium salt. Aqueous alkali is then added to generate the amine from the salt.
What conditions are needed to form a primary amine?
Ethanol is used as a solvent to prevent any substitution of the haloalkane by water to produce alcohols.
Excess ammonia is used to reduce further substitution of the amine group to form secondary and tertiary amines.
How is the aromatic amine phenylamine prepared?
it is made by the reduction of nitrobenzene. It is heated under reflux with tin and hydrochloric acid to form the ammonium salt which is then reacted with excess sodium hydroxide to produce the aromatic amine. Tin and hydrochloric acid act as a reducing agent.
What is an amino acid?
It is a compound containing both an amine, NH2, and a carboxylic acid, COOH, functional group. This means that they have similar reactions to both amines and carboxylic acids.
What reactions can happen with the amine group of an amino acid?
The amine group is basic and reacts with acids to make salts.
What 2 reactions can take place with the carboxylic acid group of amino acids?
It can react with aqueous alkalis such as sodium or potassium hydroxide to from a salt and water.
Amino acids can also easily be esterified by heating with an alcohol in the presence of conc. sulfuric acid.
