Lactic Acid → Hydroxyacetic acid--2-hydroxypropanoic acid (1/1)

To 160 g of 85% aqueous lactic acid solution and 38 g of glycolic acid was added 6.8 g of Dowex 50W and the mixture was heated in a nitrogen atmosphere under reduced pressure for 6 hours in a manner such that the inside temperature and pressure were initially 105° C. and 350 mmHg, respectively, and finally 150° C. and 30 mmHg, respectively, while removing the water distilled. Then, 6.8 g of Dowex 50W was added and the reaction was further carried out at 175° C. and 3-5 mmHg for 40 hours. While hot, the reaction mixture was filtered to thereby remove the Dowex 50W. The filtrate was cooled to give a lactic acid-glycolic acid copolymer.

1. temperaturethe mixture was heated in a nitrogen atmosphere under reduced pressure for 6 hours in a manner such that the inside temperature and pressure
2. customwere initially 105° C.
3. custom350 mmHg, respectively, and finally 150° C. and 30 mmHg, respectively, while removing the water
4. distillationdistilled
5. additionThen, 6.8 g of Dowex 50W was added
6. customwas further carried out at 175° C.
7. filtrationWhile hot, the reaction mixture was filtered
8. customto thereby remove the Dowex 50W
9. temperatureThe filtrate was cooled

ORD record

ord-6d5815529ed249f6b4873b7aba893489

Source dataset

uspto-grants-1989_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04849228