Method of refining pyromellitic acid dianhydride

Details Method of refining pyromellitic acid dianhydride Method of refining pyromellitic acid dianhydride

1974-02-11

1977-03-29

Jiles, Henry

Distillation: processes, separatory

Plural distillations performed on same material

One a distillation under positive pressure or vacuum

2603463, 2603464, C07D30789

Patent

active

040147550

ABSTRACT:
Process for purification of crude pyromellitic acid dianhydride produced by vapor phase oxidation of 1,2,4,5-tetraalkylbenzene with an oxygen-containing gas, having a purity of more than about 95% pyromellitic acid dianhydride. In a first distillation stage, said crude pyromellitic acid dianhydride is distilled at pressure of less than about 310 Torr, and temperature of less than about 350.degree. C to distill overhead an impurities containing fraction amounting to less than about 20% of the crude introduced into the first stage, and provide a residue enriched in pyromellitic acid dianhydride. In a second distillation stage, the residue of the first stage is distilled at lower pressure and at temperature of less than about 325.degree. C to distill overhead the purified pyromellitic acid dianhydride, and provide an impurities containing residue of less than about 12% of the crude introduced into the first step.

REFERENCES:
Mazitov et al., Khim. Prom. (Moscow) 1969, Vol. 45(2), pp. 98-99, Chem. Abstracts (1969) Vol. 70, 106153.

Affiliated with

Also associated with

Rating

Method of refining pyromellitic acid dianhydride does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method of refining pyromellitic acid dianhydride, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of refining pyromellitic acid dianhydride will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-547377