Process for the preparation of terephthalic acid by the hydrolys

Details Process for the preparation of terephthalic acid by the hydrolys Process for the preparation of terephthalic acid by the hydrolys

1979-09-27

1981-11-24

Trousof, Natalie

Organic compounds -- part of the class 532-570 series

Organic compounds

Carboxylic acids and salts thereof

203 73, C07C 5109

Patent

active

043025951

ABSTRACT:
In a process for the preparation of fiber-grade terephthalic acid from intermediate stage crude dimethyl terephthalate, the crude dimethyl terephthalate, which has a limited content of intermediate oxidation products including a content of terephthalaldehydic acid methyl ester of up to 0.1% by weight based on the weight of the crude dimethyl terephthalate, is hydrolyzed with water at a weight ratio of the crude dimethyl terephthalate to water of between 3:1 and 0.1:1 and at a temperature between 140.degree. C. and 350.degree. C. and under a pressure required to maintain a liquid phase (e.g., from 6 to 200 bars) to produce a reaction mixture containing crystalline fiber-grade terephtalic acid and thereafter the terephthalic acid is recovered from the reaction mixture. The initial crude dimethyl terephthalate used as a starting material is obtained from a crude ester mixture produced by the oxidation of p-xylene and/or methyl p-toluate with oxygen-containing gases in the presence of heavy metal-containing oxidation catalyst at an elevated temperature and under an elevated pressure and by esterification of the oxidation mixture with methanol at an elevated temperature and elevated pressure followed by separating the resulting crude ester mixture by distillation into a methyl p-toluate enriched fraction, a residual high-boiling fraction and the crude dimethyl terephthalate having the limited content of intermediate oxidation products.

REFERENCES:
patent: 2992168 (1961-07-01), Wilson et al.
patent: 3108132 (1963-10-01), McKinney
patent: 3396087 (1968-08-01), Claybaugh et al.
patent: 3594414 (1971-07-01), Katzschmann
patent: 4118313 (1978-10-01), Hadamovsky et al.
Butler, P. A. Chemical and Process Engineering, Oct. 1971, pp. 68-71.

Affiliated with

Also associated with

Rating

Process for the preparation of terephthalic acid by the hydrolys does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Process for the preparation of terephthalic acid by the hydrolys, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for the preparation of terephthalic acid by the hydrolys will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2175835