Esters call derivatives of mineral acids in which atoms of hydrogen of hydroxyl group are replaced on a carbonic radical. It can be mono, di and polyair.
Air is how difficult?
Difficulties begin already c of names which named esters. For their designation quite certain formula was once developed. That is the name of air can be formed of two words. As the radical the name of alcohol undertakes, then the name of acid as hydrocarbon and also the termination "at" is added to it.
Thus the following names are also created: propilmetanoat, izopripilmetanoat, ethyl acetate, melpropionat.
Production of esters not always consists in their synthesis. Substantially esters are present at the nature as are a component of essential oils of many plants. For example, the uksusnoizoamilovy air better known as "pear essence" as it is a part of essential oils of pears and also many flowers.
At the same time air of a glitserol and other highest fatty acids are a chemical basis practically of all fats and oils. Nevertheless, separate esters should be synthesized as they or seldom meet, or are in the nature in extremely limited quantity. The active catalyst is necessary for synthesis or as it is called, process of etherification between carbonic acids and alcohols, the concentrated sulfuric acid most often acts as it. It, being the process catalyst, makes active a molecule of carbonic acid. Reaction speed between carbonic acid and alcohol in many respects depends on with what atom of carbon it will be connected IT - group (primary, secondary or tertiary). Besides also the chemical nature of acid and alcohol is important, play the role and structures of a hydrocarbon chain which is connected with a carboxyl.
Reactions of hydrolysis of esters
Reaction of hydrolysis (saponification) of esters is the return etherification. Its main shortcoming – extremely low speed. Though speed can be increased considerably by additive in reaction of mix of mineral acids or alkalis. And it is interesting that saponification in the alkaline environment happens many times quicker. Thus, esters hydrolyze, as a rule, in the alkaline environment while simple air – in sour. The high resistance of esters to influence of various oxidizers defined that they began to be used in chemical synthesis long ago and also the analysis for protection of spirit and phenolic groups.