Process for producing high-grade tricaprylin

A process for producing tricaprylin 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 selected from solketal is reacted converted to tricaprylin,
• so as to produce, as a reaction product, tricaprylin of formula (II)
• wherein in formula (II) the radical R1 represents a linear saturated aliphatic C7-alkyl radical of formula —(CH2)6—CH3,
• wherein the process comprises at least one esterification step using at least one compound selected among C8-fatty acids and their anhydrides and esters;
• wherein the process comprises a combination of all four 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 selected from solketal 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 selected from solketal;
• (iv) the at least one esterification step is performed in the absence of any metal-based catalyst.

A tricaprylin,

• wherein the tricaprylin corresponds to formula (II)
• wherein, in formula (II), the radical R1 represents a linear saturated aliphatic C7-alkyl radical of formula —(CH2)6—CH3;
• wherein the tricaprylin of formula (II) is exhibits the following properties (1) to (5) in their combination:
• (1) an acid value (AV), determined according to Ph. Eur. 2.5.1 of European Pharmacopoeia 10.0:
• ≤0.5 mg KOH/g;
• and
• (2) a hydroxyl value (OHV), 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% based on the tricaprylin;
• 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 tricaprylin;
• 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 fir Fettwissenschaft e.V. [Standard method of German Society for Fat Science]):
• ≤0.5 ppm based on the tricaprylin.