Sulfuric Acid → CID 3084433

Temperature

10 °C

In the same reaction apparatus as in Example 15, 100 g of 25% fuming sulfuric acid was dropped into 500 g of tetrahydrofuran at -20° C. over 40 minutes, and then the resulting mixture was subjected to reaction at -20° C. for 2 hours. The conversion at this point was 31%. Then the reaction mixture was heated to 10° C. and subjected to reaction for 2 hours, after which 10 g of water was added to the mixture to terminate the polymerization. The final conversion was 58%. Thereafter, 400 g of water was added to the polymerization mixture, and the dropping funnel was replaced by the distilling column, after which the contents in the flask were heated and hydrolyzed in an oil bath at 100° C. with stirring for 2 hours while distilling off and recovering unreacted tetrahydrofuran. Then, the contents in the flask were allowed to stand at 100° C. to cause separation of layers and the aqueous layer was withdrawn. To the obtained PTMG layer were again added 230 g of water and 20 g of the withdrawn aqueous layer, and the resulting mixture was refluxed with heating and hydrolyzed in an oil bath at 120° C. with stirring for 2 hours and then allowed to stand at 100° C. to cause separation of layers, after which the separated aqueous layer was withdrawn. The amount of residual sulfuric ester groups in PTMG was 5 ppm and the acid number was 0.21. To the resulting PTMG layer was further added 250 g of water having suspended therein 0.25 g of basic magnesium carbonate, and the resulting mixture was subjected to heating and washing treatment in an oil bath at 100° C. for one hour while stirring the mixture vigorously, after which the mixture was allowed to stand to cause separation of layers. The mixture was not emulsified throughout the treatment, and upon allowing the mixture to stand, the mixture underwent separation of layers in a very short time, and the PTMG layer after the separation of layers was almost transparent. After removing the aqueous layer, the PTMG layer was subjected to perfect evaporation of volatile matters under reduced pressure at 80° C., and then filtered through a 10-μ mesh membrane filter to obtain 260 g of colorless transparent PTMG (yield: 52%). The thus obtained PTMG was analyzed to determine its number-average molecular weight, hydroxyl number, acid number, and amount of residual sulfuric ester groups, all of which are shown in Table 3.

1. customthe resulting mixture was subjected to reaction at -20° C. for 2 hours
2. customsubjected to reaction for 2 hours
3. customto terminate
4. customthe polymerization
5. temperatureafter which the contents in the flask were heated
6. customhydrolyzed in an oil bath at 100° C.
7. distillationwhile distilling off
8. customrecovering unreacted tetrahydrofuran
9. customto stand at 100° C.
10. customseparation of layers
11. customthe aqueous layer was withdrawn
12. temperaturethe resulting mixture was refluxed
13. temperaturewith heating and hydrolyzed in an oil bath at 120° C.
14. stirringwith stirring for 2 hours
15. customto stand at 100° C.
16. customseparation of layers
17. customafter which the separated aqueous layer was withdrawn
18. temperatureto heating
19. washwashing treatment in an oil bath at 100° C. for one hour
20. stirringwhile stirring the mixture vigorously
21. customseparation of layers
22. customthe mixture underwent separation of layers in a very short time
23. customthe PTMG layer after the separation of layers
24. customAfter removing the aqueous layer
25. customthe PTMG layer was subjected to perfect evaporation of volatile matters under reduced pressure at 80° C.
26. filtrationfiltered through a 10-μ mesh membrane
27. filtrationfilter

ORD record

ord-0f80dd6cf2684115a0a09b546397775c

Source dataset

uspto-grants-1983_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04371713