6.2 nitrogen compounds Flashcards
what are amines
compounds derived from ammonia that have a H replaced with an alkyl group
known for pungent smell
how do you name amines
use suffix -amine after carbon chain
use prefix -amino for branched/ more complex molecules
for secondary or tertiary amines each group from amine group is named separately. the longest chain has the suffix -amine
how are amines bases
lone pair on the N atom is able to form a dative bond with a proton acceptor
what are amides
compounds with an amine group directly bonded with a carbonyl group.
They can be classified as either:
Primary R-CONH2
Secondary R-CONH-R’
secondary amide formation
[ see flashcard for mechanism]
Secondary amides can be formed by the reaction of amines with carboxylic acids via a condensation reaction.
Acid anhydrides or acyl chlorides could also be used.
how are amines hydrolysed
The secondary amide group can be hydrolysed under:
Acidic conditions to form a carboxylic acid and an ammonium salt.
As the amine formed will react with the acid.
Alkaline conditions to form a carboxylate salt and an amine.
As the carboxylic acid formed will react with the alkali.
what are amino acids
alpha amino acids contain both an amine group and a carboxylic acid that is separated by a carbon atom
has the general formula RCH(NH2)COOH
R groups can be an alkyl, -OH, -SH, -COOH, -NH2 ect
[see physical flashcard for structure]
how to name amino acids
the carboxylic acid takes priority so the amino acid will always be in position 2
e.g. 2-aminobutanoic acid
what are zwitterions
the carboxyl group is able to donate a proton to amine groups, resulting in an internal salt, known as a zwitterion
have no overall charge as the charges cancel out
form at an isoelectric point- pH level is unique to each amino acid due to the attached R group
amino acid reacts as an acid with a base
the carboxylic acid group can react with a base to form a salt, and with an alcohol to form an ester
[see physical flashcard for mechanism]
what are amino acid reacts as a base
the amine group is a base and so can react with an acid, such as HCl to produce a salt
[see physical flashcard for mechanism]
the amine group can also behave as a nucleophile and can react with slightly positive carbons bonded to slightly negative X
[see physical flashcard for mechanism]
what is the formation of peptide bonds in amino acids
there are numerous other reactions that depend on both functional groups, the most important being the formation of peptide links
[see physical flashcard for mechanism]
a dipeptide bond contains a dipeptide link -CONH and 2 side chains (R groups)
dipeptides can react further with additional amino acids
what is condensation polymerisation
where 2 monomers link together to form a long chain (polymer) and there is a loss of a small molecule such as water or hydrochloric acid
there are 2 main types- polyesters and polyamides
what is terrylene (PET)
an important common ester used in synthetic fibres and containers for food and beverages
made by reacting benzen-1,4-dicarboxylic acid and ethane-1,2-diol
has a regular approximately linear structure
polymer chains pack closely together
induced dipole-dipole
what are polyesters
made of carboxylic acids and alcohols
could also use hydrocarboxylic acids which contain both a carboxylic acid and an alcohol
what are polyamides
can be prepared from 2 monomers, 1 with an amine at both ends and the other with carboxylic acids at both ends
the monomer is linked via an amine bond known as a peptide link
what is nylon
the 1st produced condensation polymer using equal parts of diamine and dicarboxylic acids so an amide is formed at both ends of each monomer
[see physical flashcard for mechanism]
what is the hydrolysis of polyesters
the ester link in polyesters and the amine link in a polyamide are polar meaning they can be subject to hydrolysis
are quite resistant to hydrolysis unless catalysed by an acid or base
what is the hydrolysis of polyesters
using an acid and a base
[see physical flashcard for table on the reagents and products]
what is the hydrolysis of polyamides
using acids and alkali
[see physical flashcard for table on the reagents and products]
what are optical isomers
all molecules have mirror images
most are superimposable (the same)
some arent superimposable as carbon is bonded to 4 different species. this means that it has a chiral centre
