Process for manufacturing monoesters of polyhydroxyalcohols

A process for the preparation of monoesters of one or more polyhydroxyalcohols, comprising:

• (v) reacting the or each polyhydroxyalcohol with a glyceride ester composition derived from a natural or synthetic source, in the presence of tertiary butanol or tertiary amyl alcohol as reaction medium, and a catalyst;
• (vi) if necessary, neutralising the catalyst;
• (vii) removing the tertiary butanol or tertiary amyl alcohol;
• and (viii) removing the unreacted polyhydroxyalcohol and any liberated glycerol from the product mixture;
• characterised in that
• in the reaction (i) the polyhydroxyalcohol is present in mass excess relative to the glyceride ester composition:
• the mass ratio of reaction medium to polyhydroxyalcohol is at least 0.8:1 in the case of tertiary butanol or at least 1.3:1 in the case of tertiary amyl alcohol;
• the reaction is carried out at a temperature at least equal to the reflux temperature of the reaction medium and at a pressure exceeding 1 bar;
• and the catalyst is selected from basic salts of Group I and Group II metals and non-metallic nitrogenous bases.