Amides are organic compounds that are considered as acid amides. Although the main dominant class of amides is the carboxyamide, phosphamides and sulphamides are also abundant.
Carboxyamindes possess at least one amide group (-CONH-).The functional group a carbonyl group (C=O) and amino group (-NH2) linked together. Amides (R – CON – R2’) are characterized by the possibility of having its R groups as a terminal H in their structure. In other words, the N can be linked with one or two H atoms instead of R groups.
The role that amides play in our real life is controlled by their properties. Amides are used in various applications in different fields such as food industry, pharmaceutics, etc.
Amides Examples
Common amides examples are:
- Benzamide
- acetamide
- Carboxamides
- Dimethylformamide
- Sulfonamides
- Phosphoramides
- paracetamol
- Nylon
First: Preparation of Amides:
The simplest form of amide is prepared from ammonia, where a hydrogen atom is replaced by an acyl group. The product is described as a primary amide where its general formula is represented as R – CO – NH2. In the same way, secondary and tertiary amides can be prepared from primary and secondary amines, respectively.
Second: General Properties of Amides:
Amides are considered very weak bases compared to their corresponding amines. This is noticed from their pKa which is around -0.5, while that of the corresponding amines exceeds 9.5. Amides are less soluble than their corresponding carboxylic acid and amines. This is attributed to the ability of the later compounds to both accept and donate hydrogen bonds. Solubility of amides can be comparable to their corresponding esters.
