Method for Post-Treating Polyol Esters

摘要

A batchwise process for aftertreatment of polyol esters prepared by reacting polyols of the general formula (II);H—(—O—[—CR1R2—]m—)o—OH   (II);in which R1 and R2 are each independently hydrogen, an alkyl radical having 1 to 5 carbon atoms, preferably methyl, ethyl or propyl, or a hydroxyalkyl radical having 1 to 5 carbon atoms, preferably the hydroxymethyl radical, m is an integer from 1 to 10, preferably 1 to 8 and especially 1, 2, 3 or 4, o is an integer from 2 to 15, preferably 2 to 8 and especially 2, 3, 4 or 5, with excess linear or branched aliphatic monocarboxylic acids having 3 to 20 carbon atoms and having a lower boiling point than the polyols used. The process is carried out in the presence of a Lewis acid and in the presence of an adsorbent, while removing the water formed, characterized in that the excess monocarboxylic acid is removed by distillation and water is added to the crude ester obtained at a temperature below the boiling point of water at the particular pressure and the crude ester with added water is aftertreated with avoidance of basic compounds, and the sparingly soluble conversion products and the adsorbent present in the esterification reaction are filtered off.

主权项

1. A batchwise process for aftertreatment of polyol esters prepared by reacting polyols of the general formula (II)
H—(—O—[—CR1R2—]m—)o—OH   (II)in which R1 and R2 are each independently hydrogen, an alkyl radical having 1 to 5 carbon atoms or a hydroxyalkyl radical having 1 to 5 carbon atoms, m is an integer from 1 to 10, o is an integer from 2 to 15, with excess linear or branched aliphatic monocarboxylic acids having 3 to 20 carbon atoms and having a lower boiling point than the polyols used, in the presence of a Lewis acid selected from the group of titanium, zirconium, hafnium, iron, zinc, boron, aluminum and tin as elements or in the form of compounds thereof as catalyst and in the presence of an adsorbent in an amount of 0.1 to 5, parts by weight per 100 parts by weight of a reaction mixture, while removing the water formed, characterized in that the excess monocarboxylic acid is removed by distillation and water is added to the crude ester obtained at a temperature below the boiling point of water at the particular pressure and the crude ester with added water is aftertreated with avoidance of basic compounds, and the sparingly soluble conversion products and the adsorbent present in the esterification reaction are filtered off.