Process for the manufacture of light colored dipropyleneglycol dibenzoate

Claim 1

Process for the manufacture of dipropyleneglycol dibenzoate isomer mixture, which comprises contacting technical methyl benzoate containing more than 80 wt.% methyl benzoate which is the product of production of dimethyl terephthalate by catalytic oxidation of p-xylene and/or methyl-p-toluate and esterification of the resulting acids with methanol, to produce a crude reaction product rich in dimethylterephthalate, treatment of the crude product to recover dimethylterephthalate and produce said technical methyl benzoate as a by-product, with dipropylene glycol commercial isomer mixture of 1,1'-oxy-di-2-propanol, 2-(hydroxypropoxy)-1-propanol, and 2,2"-oxy-di-1-propanol, in the presence of at least one of aluminum and aluminum silicon alkoxides of the formula Al(OR).sub.3 or (RO).sub.3 SiOAl(OR).sub.2 wherein the R's are alike or different and are lower alkyl, as catalyst, at temperature above 150° C, for a time sufficient for transesterification to produce said dipropyleneglycol dipropyleneglycol dibenzoate.