METHOD FOR PRODUCTION OF ISOALKENES AND THEIR MIXTURES FROM NORMAL ALKANES Russian patent published in 2001 - IPC

FIELD: petrochemical processes. SUBSTANCE: normal alkanes are fed into catalytic dehydrogenation zone, dehydrogenation-zone contact gas is fed into normal alkenes-to-isoalkenes isomerization zone in presence of hydrogen, and isomerization-zone contact gas is fed into separation zone. Isomerization zone contains catalyst: alumina on which silicon and/or halide, and/or variable-valence metal, preferably palladium, compounds are applied. Mixture isolated from isomerization-zone contact gas, containing chiefly hydrocarbons with the same number of carbon atoms as in original alkane(s), is separated either by (i) chemical binding of tert-alkene(s) in presence of acid catalyst with water and/or alcohol(s), and/or formaldehyde or by (ii) dimerization followed by separation of mixture of unreacted hydrocarbons, isolation of n-alkenes therefrom by rectification with polar agent(s) or by chemical binding by water and/or alcohol(s), and/or by dimerization, whereas n-alkanes are returned into dehydrogenation zone and n-alkenes optionally into isomerization zone, or by (iii) rectification separation with polar agent(s) followed by returning isolated alkane(s) into dehydrogenation zone and isolating tert-alkenes from distilled off polar agent by chemical binding by water and/or alcohol(s), and/or formaldehyde, or by (iv) dimerization and optionally returning stream containing mainly n-alkenes into isomerization zone. EFFECT: simplified process. 6 cl, 3 dwg, 3 tbl, 3 ex