Ap. Pleshkova et Sv. Volkovich, GC-MS DETERMINATION OF IMPURITIES IN 2-ETHYL-HEXANOL RECOVERED FROM DI-2-ETHYLHEXYL ORTHOPHTHALATE PLASTICIZER PRODUCTION, Journal of analytical chemistry, 48(12), 1993, pp. 1413-1419
The basic industrial method for large scale synthesis of di-2-ethylhex
yl orthophthalate (dioctyl phthalate, DOP) is the direct esterificatio
n of phthalic anhydride with 2-ethylhexanol (2-EH) catalyzed by tetrab
utoxytitanium (TBT). A serious shortcoming of the DOP so produced is t
he presence of color and unpleasant odor. It is assumed that this is c
aused by impurities in the starting raw material and by secondary reac
tion products which accumulate in the recycled 2-EH and pass into the
plasticizer during processing [1]. Gas chromatographic (GC) studies [2
-4] identified a total of 25 impurities present in various amounts in
2-EH obtained by various methods. Fourteen of these were detected by G
C in recycled 2-EH. However, in both the starting and recovered alcoho
l the structures of most of the impurities was not established. It is
necessary to obtain information on the impurities which accumulate in
the recycled 2-EH during production in order to optimize the process p
arameters for continuous DOP synthesis and improve the economics of th
e process. The goal of this work was selection of optimal conditions f
or chromatographic separation and identification of impurities in recy
cled 2-EH.