Claims
- 1. In a process for the preparation of tetrahydrofuran or tetrahydrofuran and .gamma.-butyrolactone from the crude product which is obtained by the hydrogenation of a compound selected from the group consisting of maleic acid, succinic acid, maleic anhydride, succinic anhydride and furmaric acid, and which contains 1,4-butanediol as the main impurity, the improvement which comprises:
- treating the crude hydrogenation product, directly and without prior work-up to remove impurities, at from 100 to 300.degree. C. with a non-oxidizing protic acid selected from the group consisting of mineral acids, solid protic acids capable of acting as Bronstedt acids and acidic organic cation exchangers, until the 1,4-butanediol is substantially completely cyclized to tetrahydrofuran, and
- then isolating tetrahydrofuran and .gamma.-butyrolactone from the reaction mixture by distillation.
- 2. An improved process as claimed in claim 1, wherein the non-oxidizing protic acid is a mineral acid selected from the group consisting of sulfuric acid and phosphoric acid.
- 3. An improved process as claimed in claim 2, wherein the non-oxidizing protic acid is sulfuric acid.
- 4. An improved process as claimed in claim 1, wherein the non-oxidizing protic acid is a phyllosilicate.
- 5. An improved process as claimed in claim 4, wherein the non-oxidizing protic acid is a bentonite.
- 6. An improved process as claimed in claim 1, wherein the non-oxidizing protic acid is an organic cation exchanger.
- 7. A process as claimed in claim 1, wherein the non-oxidizing protic acid is added to the crude hydrogenation product in an amount of from 0.01 to 10% by weight, with reference to the hydrogenation products.
- 8. A process as claimed in claim 7, wherein the amount of acid added is from 0.01 to 5% by weight.
- 9. A process as claimed in claim 7, wherein the amount of acid added is from 0.1 to 1% by weight.
- 10. A process as claimed in claim 7, wherein the added acid is sulfuric acid.
Priority Claims (1)
Number |
Date |
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Kind |
4004293 |
Feb 1990 |
DEX |
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Parent Case Info
This application is a continuation of application Ser. No. 658,086, filed Feb. 20, 1991 now abandoned.
US Referenced Citations (8)
Foreign Referenced Citations (2)
Number |
Date |
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1293151 |
Oct 1972 |
GBX |
1320839 |
Jun 1973 |
GBX |
Continuations (1)
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Number |
Date |
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Parent |
658086 |
Feb 1991 |
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