Published November 1970
This report is concerned with the cost and technology of manufacturing the anhydrides of the most important aromatic tri- and tetracarboxylic acids: trimellitic (1,2,4-benzenetricarboxylic acid) and pyromellitic (1,2,4,5-benzenetetracarboxylic acid). Largest uses for the two anhydrides are in trimellitic ester plasticizers and polyimide resins, respectively.
The most used commercial method of producing trimellitic and pyromellitic anhydrides is by the oxidation of the corresponding tri- and tetramethylbenzenes, pseudocumene and durene, respectively. Because these aromatic hydrocarbon raw materials constitute the largest single items of cost in the manufacture of the anhydrides, the cost and technology of producing these two hydrocarbons are also evaluated in the report.
All four of these products are relatively new to the chemical industry and are currently produced on a rather small scale and by only a few companies. However, demand for them is increasing, and a number of new producers, particularly overseas, have announced manufacturing projects.
Information on industry status was gathered mainly from the trade journals. Reliable statistics on production rates are not available. Process information was derived primarily from patents and other published literature.