Adamantane catalyzed paraffin isomerization

Abstract

A process is described for non-cyclic paraffin isomerization under strong acid conditions in which an adamantane hydrocarbon is used to substantially increase the reaction rate of the isomerization.

What is claimed is: 
     
       1. An isomerization process comprising contacting a C 4  -C 6  non-cyclic paraffinic hydrocarbon with a strong acid system .Iadd.selected from HBr, HF, HCl, H 2  SO 4 , HSO 3  F, CF 3  SO 3  H and mixture thereof .Iaddend.in the presence of an adamantane hydrocarbon containing at least one unsubstituted bridgehead position, .Iadd.wherein the molar concentration of the adamantane hydrocarbon in solution in the paraffin hydrocarbon is from about 0.1M to 1M .Iaddend.at a temperature of about -100° to 150° C., thereby producing a branched isomer of said paraffinic hydrocarbon. 
     
     
       2. The process of claim 1 wherein said paraffinic hydrocarbon is selected from n-butane, n-pentane, n-hexane, 2-methylpentane, 3-methylpentane isomers thereof, and mixtures thereof. .[.3. The process of claim 1 wherein said acid system contains an acid component selected from AlCl 3 , AlBr 3 , GaCl 3 , TaF 5 , SbF 5 , AsF 5 , BF 3 , HBr, HF, HCl, H 2  SO 4 , HSO 3  F, CF 3  SO 3   
     
     
        H, and mixtures thereof..]. 4. The process of claim .[.3.]. .Iadd.1 .Iaddend.wherein said acid system further contains a solvent selected from CH 3  Br, CH 2  Br 2 , CH 2  Cl 2 , 1,2-dichloroethane, 1,2,3-trichlorobenzene, 1,2,3,4-tetrachlorobenzene, pentafluorobenzene; HF, H 2  SO 4 , HSO 3  F, CF 3  SO 3  H, and mixtures 
     
     
        thereof. 5. The process of claim 1 wherein said adamantane hydrocarbon is 
     
     
        unsubstituted adamantane. 6. The process of claim 1 wherein said 
     
     
        temperature is in the range of about -50° to 100° C. 7. The 
     
     
        process of claim 1 being conducted in a continuous manner. 8. The process of claim 1 wherein said paraffin is 3-methylpentane and said product is 2-methylpentane. .[.9. The process of claim 3 wherein said strong acid 
     
     
        system contains AlCl 3 , AlBr 3 , GaCl 3  or TaF 5 ..]. 10. The process of claim 1 wherein said paraffin is n-butane and said 
     
     
        product is isobutane. 11. The process of claim 1 wherein said paraffin is 
     
     
        n-pentane and said product is isopentane. 12. The process of claim 1 wherein said paraffin is n-hexane and said product is a mixture of C 6   
     
     
        isomers containing more than 20 weight percent 2.2-dimethylbutane. 13. The process of claim 1 wherein said paraffin is a mixture of C 4 , C 5  or C 6  isomers wherein at least one fraction is not at thermodynamic equilibrium.