Process for producing high-grade fatty acide polyol esters, particularly fatty acid glycerol esters

A process for producing triglycerides of fatty acids with a high purity degree,

• wherein at least one starting material selected among 1,2,3-propantriol of formula (I)
• and its protected form and precursor is used as starting material and is reacted to the corresponding triglycerides of fatty acids,
• so as to produce, as a reaction product, one or more triglycerides of C5-C12-fatty acids of general formula (II)
• wherein in general formula (II) the radicals R1, R2 and R3, independently of one another, each represent a linear or branched, saturated or unsaturated aliphatic C4-C11-alkyl radical;
• wherein the process comprises at least one esterification step using at least one compound selected among C5-C12-fatty acids and their anhydrides and esters;
• wherein the process comprises a combination of at least three of the following measurements (i) to (iv):
• (i) a selective derivatization of halide-based impurities selected among fatty acid esters of monochloropropanediols and glycidol esters of fatty acids, present in the resulting reaction product, is performed by treating the resulting reaction product with at least one nucleophilic agent selected from the group consisting of hydrogen sulfites, sulfites, hydrogen thiosulfates, thiosulfates, hydrogen phosphites, phosphites and phosphines as well as combinations thereof;
• (ii) the at least one esterification step is performed at temperatures not exceeding 180° C.;
• (iii) the starting material selected among the 1,2,3-propantriol of formula (I) and its protected form and precursor is used and selected such to be free of any chlorinated species and comprises a total chlorinated species content of at most 1 ppm, based on the 1,2,3-propantriol of formula (I) and its protected form and precursor;
• (iv) the at least one esterification step is performed in the absence of any metal-based catalyst.

A triglyceride of C5-C12-fatty acids,

• wherein the triglyceride of C5-C12-fatty acids corresponds to general formula (II)
• wherein, in general formula (II), the radicals R1, R2 and R3, independently of one another, each represent a linear or branched, saturated or unsaturated aliphatic C4-C11-alkyl radical;
• wherein the triglyceride of C5-C12-fatty acids exhibits the following properties (1) to (5) in their combination and fulfils the following product specification:
• (1) an acid value, determined according to Ph. Eur. 2.5.1 of European Pharmacopoeia 10.0:
• ≤0.5 mg KOH/g;
• and
• (2) a hydroxyl value, determined according to Ph. Eur. 2.5.3 of European Pharmacopoeia 10.0:
• ≤0.5 mg KOH/g;
• and
• (3) a triglyceride content, determined according to Ph. Eur. 2.2.28 of European Pharmacopoeia 10.0:
• ≥99%;
• and
• (4) a total content of fatty acid esters of monochloropropanediols, determined according to method of DGF C-VI 18 (10) (Einheitsmethode der Deutschen Gesellschaft für Fettwissenschaft [Standard method of German Society for Fat Science]):
• ≤0.5 ppm based on the triglyceride of C5-C12-fatty acids;
• and
• (5) a total content of glycidol esters of fatty acids, determined according to method of DGF C-VI 18 (10) (Einheitsmethode der Deutschen Gesellschaft für Fettwissenschaft e.V. [Standard method of German Society for Fat Science]):
• ≤0.5 ppm based on the triglyceride of C5-C12-fatty acids.