Purification of transesterification mixtures

Claim 1

IN A PROCESS FOR REFINING ESTERS OF SOLID POLYHYDRIC ALIPHATIC ALCOHOLS AND CARBOXY ACIDS, SAID ESTER HAVING BEEN SYNTHESIZED BY A TETRANSESTERIFICATION REACTION BETWEEN SAID POLYHYDRIC ALCOHOL AND ANOTHER ESTER UNDER CONDITIONS WHICH YIELD A CRUDE MIXTURE WHICH HAS BEEN STABILIZED BY DEACTIVATION OF THE ALKALINE TRANSESTERIFICATION CATALYST, AND WHICH CONTAINS AN ESTER PRODUCT WHICH IS OVER 50% BY WEIGHT MONOESTERIFIED POLYHYDRIC ALCOHOL ESTER, AND AT LEAST ONE IMPURITY REMOVABLE BY DISTILLATION UNDER VACUUM, THE IMPROVEMENT WHICH COMPRISES INCORPORATING IN SAID CRUDE MIXTURE AT LEAST ONE FLUXING AGENT WHICH IS AN OXYGENATED POLAR ORGANIC COMPOUND HAVING A VAPOR PRESSURE UNDER DISTILLATION CONDITIONS LESS THAN THE VAPOR PRESSURE OF SAID IMPURITY TO BE REMOVED, SAID FLUXING AGENT HAVING FROM 2 TO 12 CARBON ATOMS AND CONTAINING AT LEAST 2 POLAR GROUPS SELECTED FROM THE GROUP CONSISTING OF HYDROXYL, CARBOXYL, CARBOXY ESTER AND KETONE CARBONYL AND HAVING OXYGEN PRESENT IN THE RATIO OF AT LEAST 1 ATOM PER 3 ATOMS OF CARBON AND SELECTED FROM THE GROUP CONSISTING OF (A) ALIPHATIC DIOLS HAVING 2 TO 6 CARBON ATOMS, AND ESTERS THEREOF WITH THE LOWER FATTY ACIDS WHICH HAVE FROM 2 TO 4 CARBON ATOMS IN THE MOLECULE, (B) ALIPHATIC TRIOLS HAVING FROM 2 TO 6 CARBON ATOMS AND ESTERS THEREOF WITH THE LOWER FATTY ACIDS WHICH HAVE FROM 2 TO 4 CARBON ATOMS IN THE MOLECULE, (C) ESTERS OF ALIPHATIC DI-CARBOXYLIC ACIDS HAVING FROM 4 TO 6 CARBON ATOMS AND ESTERS OF MALIC ACID WITH LOWER MONOHYDRIC PRIMARY AND SECONDARY ALIPHATIC ALCOHOLS HAVING FROM 1 TO 4 CARBON ATOMS, SAID ESTERS HAVING FROM 5 TO 10 CARBON ATOMS IN THE ESTER MOLECULE, (D) ESTERS OF METHYL AND ETHYL ALCOHOLS WITH AN ACID SELECTED FROM THE GROUP CONSISTING OF ACONITIC, TARTARIC AND CITRIC, (E) ESTERS OF LACTIC ACID WITH THE LOWER PRIMARY AND SECONDARY ALIPHATIC MONOHYDRIC ALCOHOLS HAVING FROM 3 TO 6 CARBON ATOMS AND ALIPHATIC DIOLS HAVING FROM 2 TO 6 CARBON ATOMS IN WHICH ONLY ONE HYDROXYL OF THE DIOL IS ESTERFIED, (F) ESTERS OF ACETOACETIC ACID AND LEVULINIC ACID WITH THE PRIMARY AND SECONDARY ALIPHATIC MONOHYDRIC ALCOHOLS WHICH HAVE FROM 1 TO 5 CARBON ATOMS AND THE ALIPHATIC DIOLS HAVING FROM 2 TO 6 CARBON ATOMS IN WHICH ONLY ONE HYDROXYL OF THE DIOL IS ESTERIFIED, AND SUBJECTING SAID CRUDE MIXTURE INCLUDING SAID FLUXING AGENT TO DISTILLATION TO REMOVE SAID IMPURITY THEREFROM, THE AMOUNT OF SAID FLUXING AGENT BEFORE THE DISTILLING BEING AT LEAST 1% BY WEIGHT OF THE SUM OF WEIGHTS OF THE POLYHYDRIC ALCOHOL ESTER AND THE UNREACTED POLYHYDRIC ALCOHOL, SAID FLUXING AGENT HAVING THE PROPERTY OF AND BEING PRESENT IN AN AMOUNT SUFFICIENT FOR MAINTAINING SAID CRUDE REACTION MIXTURE IN A MORE FLUID STATE TO FACILITATE THEREBY THE DISTILLATION OF SAID IMPURITY.