Dimethyl terphthalate

Hercules Chemical produced an acidic organic waste derived from the manufacture of dimethyl terphthalate, which is used in the production of synthetic liber. The average dissolved organic carbon concentration was about 7100 mg/L and included acetic acid, formic acid, p-toluic acid, formaldehyde, methanol, terphthalic acid, and benzoic acid. The pH ranged from 3.5 to 4.0. The waste also contained traces (less than 0.5 mg/L) of 11 other organic compounds, including dimethyl phthalate, a listed hazardous waste. 

In addition. Cooper et al. [91] discussed the use of a Raman analyzer to provide feedback and feed-forward data on a number of chemical manufacturing processes originating from crude oil, where several of the production steps involved a distillation separation again, in these examples, the Raman analyzer was positioned at the outlet to the distillation tower. They claim from their work that a Raman analyzer would be useful for monitoring and controlling aromatic extraction, liquid paraffin aromatization, and the production of cumene, cyclohexane from benzene, ethylbenzene, xylene isomers, dimethyl terphthalate, and styrene. It should also be noted that in all these processes, at least one and in several cases multiple distillation columns are involved. 

Lee S H, Lim S W and Lee K H (1999) Properties of potentially biodegradable copolyesters of (succinic acid-1,4-butanediol)/(dimethyl terphthalate-l,4-butanediol), Polym Int 48 861-867. 

Polybutylene terphthalate (PBT) is a semicrystalline thermoplastic polyester considered as a medium performance engineering polymer. It is produced industrially in a two-step batch or continuous process. The first step involves the transesterification of dimethyl terephthalate (DMT) with 1,4-butanediol (BDO) to produce hydrobutyl terephtlate (bis-HBT) at a temperature of 200 C. The second step consists to the polycondensation of bis-HBT at 250 C to yield PBT. It exhibits both excellent electrical properties and chemical resistance. When reinforced with glass fibers, it has improved stiffness and mechanical strength. Typical uses include connectors, capacitors and cable enclosures. PBT is also used in hot appliances such as iron and kettles. 

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