Dow Global Technolgoies LLC

Johann Haltermann Limited

Rainer Potthast

Glenn A Miller

Indresh Mathur

Chi Ping Chung

Edward H Yonemoto

A process of refining a crude C-Caliphatic diol, preferably, a C-Cmonocyclic aliphatic diol, more preferably, an isomeric mixture of cis/trans-(1,3)(1,4)-cyclohexanedimethanol, containing in addition to the diol one or more impurities selected from phenols, and aliphatic mono-ols, esters, carboxylic acids, and hemiacetals, and mixtures thereof. The refining process involves distilling the crude C6-C16 aliphatic diol in the presence of an alkali or alkaline earth metal compound, preferably, an excess thereof relative to acid equivalents present in the diol.

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Methods for purifying glycerin contaminated with one or more lower boiling alcohols such as methanol, ethanol, straight, branched or cyclic C3-C6 alcohols, and the like. The methods are particularly useful for purifying crude glycerin phases recovered from the synthesis of biofuels. The present invention uses distillation techniques to strip alcohol contaminants from glycerin. In contrast to conventional methods that carry out distillation either under substantially anhydrous or very wet conditions, the present invention carries out distillation in the presence of a limited amount of water, e.g., from about 0.8 to about 5 parts by weight of water per 100 parts by weight of contaminated glycerin to be purified.

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Houston, TX, United States of America

Rainer Potthast