| 摘要 |
<p>The invention relates to citric esters and to a process for obtaining the same, said esters having plasticizing properties for polymers, lubricating properties for processing polymers and show features specific to fluids used in tribology and which correspond to the general formula, wherein R2 is a radical of aliphatic-aromatic type with the formula, in which R3 is a nonyl radical, and R1 and R are either the same and an alkyl radical with linear or branched chain, or different, and R1 is a linear or branched alkyl radical and R is a R2 radical. According to the invention, the process consists in the citric acid esterification with alcohols, in nitrogen atmosphere, in acid catalysis, in two stages where the alcohols are added successively, in the presence of a solvent which has also the role of azeotropic entrainer of the reaction water, said esterification being followed by repeated washing with demineralized water, up to a neutral pH, vacuum devolatilization, heat bleaching with activated charcoal and filtration.</p> |
