what is ammonolysis?
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Answer:
Ammonolysis (amino meaning "contains NH2 group", and lysis meaning "to unbind") is any chemical compound reacts with a molecule of ammonia or an amine and causes a molecule to split into two parts, containing the addition of (or substitution by) an amino group —NH—.The subset of aminolysis reactions involving ammonia is known as ammonolysis.
Alkyl group
An example of an aminolysis reaction is the replacement of a halogen in an alkyl group (R-X) by an amine (R'-NH2) and the elimination of hydrogen halide (HX).
R-X + R'-NH2 → R-NH-R' + HX
Synthesis of peptides
Another common example is the reaction of a primary amine or secondary amine with a carboxylic acid or with a carboxylic acid derivative to form an amide. This reaction is widely used, especially in the synthesis of peptides. On the simple addition of an amine to a carboxylic acid, a salt of the organic acid and base is obtained. To overcome this, the carboxylic acid first needs to be "activated". This is usually done by converting the acid into a more reactive derivative (i.e. anhydride, acid halide) or by using a coupling agent. In some cases, high temperatures (>200 °C) can overcome salt formation by driving off water, without the need for "activation" of the carboxyl group. The downside to this simple reaction is that the compounds may decompose at these elevated temperatures.
The carboxylic acid derivatives can be esters, anhydrides, acid halides or any other activated species.
The choice of activated carboxyl group or coupling agent can be very important in peptide synthesis, as using the wrong one can lead to racemization.
Synthesis of amides from carboxylic acids
Making an amide is one of the processes which require ammonia as a reactant. There are other processes of preparing an amide such as from acid anhydrides and acyl chloride.
Carboxylic acids react with ammonium carbonate, to convert the carboxylic acids to ammonium salts. For example, acetic acid reacts with ammonium carbonate to produce ammonium acetate.
Carboxylic acid reacts with ammonium carbonate
After the reaction is completed, ammonium acetate is heated under reflux (170 °C) to dehydrate the salt and eliminate excess acetic acid and water producing acetamide[4]: