Purification of propylene oxide by extractive distilation.

摘要

An extractive distn. process for the distn. of impure propylene oxide (PO) feedstock in an extractive distn. column to remove oxygenated contaminants including water, methanol and acetone from the impure PO, comprises: (i) introducing the impure PO feedstock into the lower half of an extractive distn. column; (ii) introducing an extractive distn. agent (I) comprising a mixt. of PO adducts of oxyethylene glycols, in which the adducts are of formula (1), into the column above the point of introduction of the feedstock, (I) being used at a ratio of feedstock to (I) of 1:1 to 20:1; (iii) withdrawing a lighter distn. fraction from the column, comprising PO contaminated with reduced amts. of the water, acetone and methanol; and (iv) withdrawing a heavier distn. fraction from the column, contg. all of (I) and a portion of the water, acetone and methanol; n = 1-4; m = 1-3; and average mol. wt. of mixt. = 250-350.