PROMOTING ACTION OF POCL3 IN O-PHOSPHORIC ACID ESTERIFICATION BY N-BUTANOL

The opportunity of tri-n-butylphosphate(TBP) synthesis via esterificat ion of o-phosphoric acid with n-butanol, under special conditions, was investigated. The reagents were contacted without solvent in an autoc lave, in the presence of small amounts of phosphorus oxichloride(ca. 6 .10(-4) mole per gram of reaction mixture), under argon pressure, duri ng 3 hours. A strong dependence is observed between all operating para meters i.e. temperature, pressure, phosphorus oxichloride content and the reagents mole. The results obtained show clearly the promoting act ion of phosphorus oxichloride. It was also depicted that TBP synthesis is the main reaction in such conditions. An additive optimization stu dy allowed to confirm the previous observations. Compared to the class ical TBP synthesis ways, the present procedure appears as being a very interesting low cost alternative if one takes into account that the u se of phosphorus oxichloride as reagent is avoided.