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what are amines?
amines are organic compounds derived from ammonia in which one or more of the hydrogen atoms in ammonia have been replaced by a carbon chain or ring
What do amines behave as? And why?
Amines behave as bases as the lone pair of electrons on the nitrogen atom can accept a proton
How do you form a primary amine?
The lone pair of electrons on the nitrogen means that ammonia can act as a nucleophile in a substitution reaction with a haloalkane. This produces an ammonium salt. The salt can then be reacted with an aqueous alkali forming the amine
What are the conditions when forming a primary amine?
An alcohol must be used as the solvent to prevent any substitution of the haloalkane by water to produce an alcohol
Excess ammonia is used to prevent further substitution of the amine group to form secondary or tertiary amines
How do you form seconday or tertiay amines?
An unpure pimary amine is formed from the previous reaction, therefore a lone pair of electrong still remains on the nitrogen in the product. By further reacting the primary amine with a haloalkane, another ammonium salt will form e.g. dipopylammonium chloride. This is then reacted with an aqueous alkali e.g. NaOH to form the seconday amine. e.g. dipropylamine.
For form a tertiary amine, continue reacting the secondary amine.
How do you form phenylamine?
It is made by the reduction of nitrobenzene. Nitrobenzene is heated under refluxed with tin and hydrochloric acid to produce the ammonium salt, phenylammonium chloride. It is then reacted with excess sodium hydroxide to form the aromatic amine, phenylamine
What are amino acids?
They are oganic compounds containing both amines, -NH2 and carboxylic acids, -COOH, functional groups
How do amino acids react?
Due to the amine group being basic, they can react with acids to form salts. The carboxylic acid group will also mean that they can react with aqueous alkali to also form salts or react with alcohol to form esters.
What must the amino acid be reacted with to form esters?
An alcohol and concentrated sulfuric acid
What is a zwitterion?
When an ion contains both a positive and negative charge. E.g. within an amino acid, the amine group can accept a proton from the carboxylic acid group
What is the charge on a zwitterion?
There is no overall charge as the positive and negative charges cancel out
What is the isoeletric point?
The pH at which the zwitterion is formed
What happens if the pH is above the isoeletric point?
Then the amino acid acts as an acid and looses a proton to form a negative ion
What happens if the pH is lower than the isoeletric point?
The amino acid acts as a base and gains a proton to form a positive ion
What are amides?
The products of reactions of acyl chlorides with ammonia and amines
What is stereoisomerism?
Compounds with the same structural formula but different arrangement of atoms
What is a chiral centre?
When a carbon atoms is attached to four different atoms or group of atoms
What is condensation polymerisation?
the joining of two monomers with loss of a small molecule like water or hydrogen chloride in which two different functional groups are needed
What two functional groups are needed to make a polyester?
A carboxylic acid or an alcohol
What are polyamides?
polyamides are condensation polymers formed when monomers are joined together by amide linkages in a long chain to form the polymer
What two functional groups are needed to make a polyamide?
A carboxylic acid (or acyl chloride) and an amine group
How do you hydrolyse condensation polymers?
By using hot aqueous alkali such as NaOH or by hot aqueous acid like HCl
Which is preferable to hydrolyse a condensation polymer with: acid or alkali?
hydrolysing with a base is preferable because it is not a reversible reaction like hydrolysis with an acid
What are amino acids general formula?
RCH(NH2)COOH
How may enantiomers be distinguished from one another?
By using a plane polarized light. The enantiomers rotate the plane in opposite directions
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