Claims
- 1. A process of preparing an unsaturated aliphatic hydrocarbon and water as a by-product comprising contacting an aliphatic hydrocarbon having at least three carbon atoms with a solid heterogeneous catalyst composition having reactive oxygen under conditions such that an unsaturated aliphatic hydrocarbon is produced in a productivity of at least about 0.2 g/g cat-hr and water is produced as a by-product, the catalyst composition comprising (a) a support component containing magnesia and at least one aluminum oxide selected from the group consisting of Al.sub.2 O.sub.3 and MgAl.sub.2 O.sub.4, the support having a MgO/Al.sub.2 O.sub.3 weight ratio in the range from about 0.30 to about 4.0, and a surface area of at least about 25 m.sup.2 /g; and (b) a catalyst component consisting essentially of an oxide of magnesium, an oxide of molybdenum wherein the molybdenum is in the +6 oxidation state, and a promoting amount of an alkali metal promoter.
- 2. The process of claim 1 wherein the aliphatic hydrocarbon is an alkane represented by the general formula:
- CH.sub.3 --(CH.sub.2).sub.n --CH.sub.3
- wherein n is an integer from 1 to about 8.
- 3. The process of claim 2 wherein n is 2 and the alkane is n-butane.
- 4. The process of claim 1 wherein the aliphatic hydrocarbon is diluted with a non-reactive gas.
- 5. The process of claim 4 wherein the hydrocarbon concentration ranges from about 40 mole percent to about 100 mole percent.
- 6. The process of claim 1 wherein the oxide of magnesium and the oxide of molybdenum are partially combined in the form of magnesium molybdate.
- 7. The process of claim 1 wherein the alkali metal promoter is an alkali metal oxide, hydroxide, carbonate, acetate, or oxalate.
- 8. The process of claim 7 wherein the alkali metal is cesium.
- 9. The process of claim 7 wherein the alkali metal is potassium.
- 10. The process of claim 1 wherein the weight ratio of magnesia to alumina is in the range from about 0.30 to about 2.0.
- 11. The process of claim 1 wherein the temperature is in the range from about 400.degree. C. to about 700.degree. C.
- 12. The process of claim 1 wherein the aliphatic hydrocarbon partial pressure is in the range from about subatmospheric to about 100 psig.
- 13. The process of claim 1 wherein the gas hourly space velocity of the feedstream is in the range from about 100 hr.sup.-1 to about 20,000 hr.sup.-1.
- 14. The process of claim 1 wherein the unsaturated aliphatic hydrocarbon is a diolefin and wherein the diolefin is represented by the general formula:
- CH.sub.2 .dbd.CH--CH.dbd.CH--(CH.sub.2).sub.m --H
- wherein m is an integer from 0 to about 6.
- 15. The process of claim 14 wherein m is 0 and the diolefin is 1,3-butadiene.
- 16. The process of claim 1 wherein the concentration of the alkali metal promoter is in the range from about 0.05 weight percent to about 5 weight percent calculated as the alkali hydroxide and based on the total weight of the aluminum, magnesium and molybdenum oxides.
- 17. The process of claim 16 wherein the concentration of alkali metal promoter :s in the range from about 0.1 weight percent to about 2 weight percent.
- 18. The process of claim 1 wherein the catalyst composition has an attrition number less than about 5 weight percent hr.sup.-1.
- 19. A process of preparing an unsaturated aliphatic hydrocarbon and water as a by-product comprising contacting an aliphatic hydrocarbon having at least three carbon atoms with a solid heterogeneous catalyst composition having reactive oxygen under conditions such that an unsaturated aliphatic hydrocarbon is produced in a productivity of at least about 0.2 g/g cat-hr and water is produced as a by-product, the catalyst composition comprising (a) a support component containing magnesia and at least one aluminum oxide selected from the group consisting of Al.sub.2 O.sub.3 and MgAl.sub.2 O.sub.4, the support having a MgO/Al.sub.2 O.sub.3 weight ratio in the range from about 0.30 to about 4.0, and a surface area of at least about 25 m.sup.2 /g; and (b) a catalyst component consisting essentially of an oxide of magnesium, an oxide of molybdenum wherein the molybdenum is in the +6 oxidation state, an oxide of vanadium and a promoting amount of an alkali metal promoter.
- 20. A process of preparing 1,3-butadiene and water as a by-product comprising contacting n-butane with a solid heterogeneous catalyst composition containing reactive oxygen at a temperature in the range from about 500.degree. C. to about 650.degree. C., and a pressure in the range from about 1 psig to about 30 psig and under such other reaction conditions that a mixture of products is formed containing 1,3-butadiene in a productivity of at least about 0.2 g/g cat-hr and water is produced as a by-product, said catalyst composition comprising (a) a support component containing magnesia and at least one aluminum oxide selected from the group consisting of alumina and magnesium aluminate spinel, the support having a MgO/Al.sub.2 O.sub.3 weight ratio in the range from about 0.3 to about 4.0, and a surface area of at least about 25 m.sup.2 /g; and (b) a catalytic component consisting essentially of magnesia, molybdenum oxide wherein the molybdenum is in the +6 oxidation state, and an alkali metal promoter in a concentration from about 0.05 weight percent to about 5 weight percent calculated as the alkali hydroxide and based on the total weight of the aluminum, magnesium and molybdenum oxides.
- 21. The process of claim 20 wherein the selectivity to butadiene is at least about 60 mole percent.
- 22. The process of claim 21 wherein the selectivity to butadiene is at least about 70 mole percent.
- 23. The process of claim 20 wherein the productivity of butadiene is at least about 0.4 g/g cat-hr.
- 24. The process of claim 23 wherein the productivity of butadiene is at least about 0.9 g/g cat-hr.
- 25. The process of claim 20 wherein the sum of the selectivities to C.sub.4 alkenes is at least about 60 mole percent.
- 26. The process of claim 20 wherein the sum of the selectivities to C.sub.4 alkenes is at least about 80 mole percent.
- 27. The process of claim 1 wherein the support component has a surface area in the range from about 50 m.sup.2 /g to about 250 m.sup.2 /g.
- 28. The process of claim 1 wherein the support is prepared from a pre-formed alumina having a particle size in the range from about 200 .mu.m to about 1700 .mu.m.
- 29. The process of claim 1 wherein the particle size of the catalyst composition ranges from about 200 .mu.m to about 1700 .mu.m.
- 30. The process of claim 29 wherein the particle size of the catalyst composition ranges from about 500 .mu.m to about 1200 .mu.m.
- 31. The process of claim 29 wherein the particle size of the catalyst composition ranges from about 600 .mu.m to about 1000 .mu.m.
- 32. The process of claim 20 wherein the particle size of the catalyst composition ranges from about 500 .mu.m to about 1200 .mu.m.
- 33. The process of claim 1 wherein the process is conducted in a transport reactor.
CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of Ser. No. 383,107, filed Jul. 20, 1989 and now U.S. Pat. No. 4,973,791.
US Referenced Citations (30)
Non-Patent Literature Citations (5)
Entry |
Derwent 06949C/04 (1980). |
Derwent 75459E/36 (1982). |
Chemical Abstracts 104: 131946b (1986). |
Derwent 86-316078/48. |
Derwent 85-232465/38. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
383107 |
Jul 1989 |
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