Glycerol ester
Glycerin esters are esters that contain glycerin . Esters are made from an alcohol and a carboxylic acid. In glycerine esters, the alcohol is glycerine.
The acid can be a carboxylic acid . This results in esters like those found in the typical representatives of animal and vegetable oils and fats .
The acid can also be a mineral acid (e.g. nitric acid ). A typical representative of such esters is “nitroglycerin”, which is correctly called glycerol trinitrate .
In the case of glycerol esters, a distinction is made between mono-, di- and triesters depending on the number of alcohol molecules esterified with the glycerol molecule. Phospholipids such as phosphatidylcholines are usually esterified with a substituted or unsubstituted phosphoric acid and one or two fatty acids.
The reaction of alcohols and acids to form esters is called esterification . Since one water molecule is formed per ester bond during the reaction, esterification belongs to the type of condensation reaction . Small amounts of strong mineral acids (usually sulfuric acid ) serve as catalysts . The esterification is subject to chemical equilibrium , so the ester yield increases when water is removed from the reaction mixture.
use
Glycerine ester (usually obtained from the root resin of conifers by steam distillation ) is mainly used to stabilize the appearance and color of non-alcoholic beverages. So far, no harmful side effects are known.
Glycerine esters from root resin are approved in the EU as food additives with the designation E 445 .
Nitroglycerin is used as a drug and as an explosive .
See also
Individual evidence
- ^ Siegfried Hauptmann : Organic Chemistry , 2nd revised edition, VEB Deutscher Verlag für Grundstoffindustrie, Leipzig, 1985, pp. 653–654, ISBN 3-342-00280-8 .