Extraction of carboxylic acids with tin compounds

摘要

A method of removing a carboxylic acid from a liquid including a tertiary amide solvent includes: forming an extraction medium including an acid-extracting tin species and an extraction solvent that is immiscible with the tertiary amide solvent; subsequently contacting the liquid with the extraction medium, forming a phase including a de-acidified tertiary amide solvent and a phase including the extraction solvent; and removing the phase including the extraction solvent, to afford a liquid including the de-acidified tertiary amide solvent. The acid-extracting tin species is one or more tin species obtained by reaction of a di(hydrocarbyl) tin oxide with less than one equivalent of a carboxylic acid, or tin species obtainable by reaction of a 1,3-diacyloxy-1,1,3,3-tetra-(hydrocarbyl)distannoxane with an aqueous base. A method of preparing a sucralose-6-acylate includes uses the foregoing method to remove a carboxylic acid from a liquid including a tertiary amide solvent and the sucralose-6-acylate.

主权项

1. A method of removing a carboxylic acid from a liquid comprising a tertiary amide solvent, comprising the steps of:
A) forming an extraction medium comprising an acid-extracting tin species and an extraction solvent that is immiscible with the tertiary amide solvent; B) subsequently contacting the liquid comprising the tertiary amide solvent with said extraction medium, thereby forming a phase comprising a de-acidified tertiary amide solvent and a phase comprising the extraction solvent; and C) removing the phase comprising the extraction solvent, to afford a liquid comprising the de-acidified tertiary amide solvent; wherein said step A) of forming the extraction medium comprises contacting a solution comprising a 1,3-diacyloxy-1,1,3,3-tetra-(hydrocarbyl)distannoxane in the extraction solvent with aqueous base to thereby form an aqueous phase and the extraction medium as a separate phase, and removing the aqueous phase.