PRODUCTION OF ESTERS BY ETERIFICATION OF FATTY ACIDS OF SUNFLOWER, OLIVE AND SOYBEAN OILS WITH MANNITOL, SORBITOL AND XYLITOL

Abstract

Polyol esters are widely used in various fields of science and technology, food industry, sanitation, medicine, cosmetics, etc. In engineering, polyol esters are mainly used as high-temperature lubricating oils․Esters of polyols with a degree of substitution from 1:1 to 3:1 are used as emulsifiers, stabilizers, defoamers, dispersants and detergents. Esters of saturated carboxylic acids С12 – С18 – with a degree of substitution from 4:1 to 6:1 are thick or hard oils and are used in medicine, pharmacy and cosmetology. In our early studies, with the esterification of mannitol and other C4 – C6 polyols with some higher aliphatic acids in molar ratios of 1: 3÷6, various esters were obtained. The synthesized oil-like products were similar in their physicochemical and rheological properties to natural fats and oils and had melting points in the range of –10...64 °C. However, differing from artificial oils, natural fats and oils contains variety of saturated and unsaturated fatty acids C6 – C12. Therefore, in order to obtain more natural oil and fat substitutes, it seems appropriate to obtain esters of higher polyols with a complex of natural fatty acids. This paper presents data on obtaining a complex of fatty acids of sunflower, olive and soybean oils and further synthesis of esters with mannitol, sorbitol and xylitol in molar ratios of 1: 3...6. The studies were carried out according to the following scheme: A) hydrolysis of sunflower, olive and soybean oils with an alkali solution, with the formation of a mixture of carboxylic acids, consisting mainly of oleic, linoleic, stearic and palmitic acids; B) neutralization of alkali salts, isolation and drying of fatty acids mixtures; C) esterification of mannitol, sorbitol and xylitol with fatty acid complexes; D) purification and drying of non-glyceride oils; E) determination of the main physicochemical properties of the obtained artificial oils. The reaction progress is monitored by HPLC method on an Agilent Infinity II HPLC 1260 System instrument and by IR spectra method on an IKS 29 instrument. The completion of polyol esterification reactions with fatty acid complexes is determined by the disappearance of absorption bands in the IR spectra in the region of 1740 and 2500...2700 cm˗1. Outputs of artificial oils in optimal conditions reach 95-97%. Non-glyceride oils are intended for testing as substitutes for natural oils and fats.