Sulfuric Acid → CID 3084433

Temperature

30 °C

In the same reaction apparatus as in Example 15, 126 g of 25% fuming sulfuric acid containing 0.9 g of sodium borofluoride was dropped from the dropping funnel into 600 g of tetrahydrofuran at -10° C. with stirring over 40 minutes, after which the resulting mixture was subjected to reaction at -10° C. for one hour. The conversion at the end of this reaction was 39%. Then, the reaction mixture was heated to 30° C. and subjected to reaction at this temperature for 2 hours, after which 10 g of water was added to the mixture to terminate the polymerization. The final conversion was 60%. Then, 530 g of water was added (sulfuric acid concentration was about 20%), and the reaction solution was heated and hydrolyzed in an oil bath at 80° C. while distilling off the unreacted tetrahydrofuran in the same manner as in Example 1, and then 204 g of a 48% by weight sodium hydroxide solution (corresponding to 90% neutralization degree) was added continuously over a period of one hour while the internal temperature was kept at 100° C. to continue the hydrolysis. The recovery of unreacted tetrahydrofuran by distillation was continued during these operations. Then, in the same manner as in Example 1, the reaction mixture was allowed to stand to cause separation of layers, after which the aqueous layer was withdrawn. The PTMG layer was washed at 80° C. for one hour with 350 g of a 20% by weight aqueous sodium sulfate solution. After separating and withdrawing the aqueous layer again, the volatile matters were removed in the same manner as in the foregoing Examples and the residue was filtered through a 10-μ mesh membrane filter to obtain PTMG. The results of the analyses of the thus obtained PTMG were as shown in Table 2.

1. customafter which the resulting mixture was subjected to reaction at -10° C. for one hour
2. customsubjected to reaction at this temperature for 2 hours
3. customto terminate
4. customthe polymerization
5. temperaturethe reaction solution was heated
6. customhydrolyzed in an oil bath at 80° C.
7. distillationwhile distilling off the unreacted tetrahydrofuran in the same manner as in Example 1
8. addition204 g of a 48% by weight sodium hydroxide solution (corresponding to 90% neutralization degree) was added continuously over a period of one hour while the internal temperature
9. customwas kept at 100° C.
10. customthe hydrolysis
11. distillationThe recovery of unreacted tetrahydrofuran by distillation
12. customseparation of layers
13. customafter which the aqueous layer was withdrawn
14. washThe PTMG layer was washed at 80° C. for one hour with 350 g of a 20% by weight aqueous sodium sulfate solution
15. customAfter separating
16. customwithdrawing the aqueous layer again
17. filtrationthe residue was filtered through a 10-μ mesh membrane
18. filtrationfilter

ORD record

ord-6999d49250824c6db4d91ac516e42cb1

Source dataset

uspto-grants-1983_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04371713