Terephthalic Acid → Bis(2-hydroxyethyl) terephthalate

Participants

Reaction Conditions

Reaction Steps

A 3-liter stirred autoclave is charged with 600 grams (3.6 moles) of fiber grade terephthalic acid, 1600 ml. chlorobenzene, 12.4 grams of the terephthalic acid salt of hydroxyethylated polyethyleneimine as prepared in Example 2, and then purged with nitrogen. Liquid ethylene oxide (8.6 moles is then pumped in and the reactor heated to 175°C. by passing steam through internal coils. The temperature is maintained at 175°C. for about 30 minutes with the pressure varying during thee period from about 215 p.s.i.g. at the beginning of the period to 80 p.s.i.g. at the end of the period. After the 30 minute period, the reaction is terminated by pressuring the contents of the autoclave into a vessel where ethylene oxide is flashed and then the unreacted terephthalic acid and other solids removed by filtration. Cooling of the filtrate to about 30°C. yields about 760 grams of bis(2-hydroxyethyl) terephthalate (dry basis). Conversion of the terephthalic acid charged to the diester product is about 91 mole percent.

Provenance & Evidence