Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
146 words
A process for obtaining butenes-2 from a C 4 -hydrocarbon mixture which contains butene-1 and n-butane and may or may not contain butenes-2, comprising (a) feeding the starting C 4 -hydrocarbon mixture to the isomerization zone and/or distillative separation zone; (b) isomerizing the butene-1 in an isomerization zone in the presence of an acidic catalyst at from 100° to 350° C.; (c) passing the isomerization mixture obtained from the isomerization zone into a distillation separation zone; (d) removing a butene-1-containing fraction which additionally contains trans-butene-2 above the lower third of the distillative separation zone, and passing it to the isomerization zone; (e) removing at the same time an n-butane-containing fraction from the distillative separation section at a point above the lower third of the distillative separation zone; and (f) removing the butenes-2 or a fraction containing these in the lower third of the distillative separation zone.
Claim 2
Dependent Claim
146 words
A process for obtaining butenes-2 from a C 4 -hydrocarbon mixture which contains butene-1 and n-butane and may or may not contain butenes-2, comprising (a) feeding the starting C 4 -hydrocarbon mixture to the isomerization zone and/or distillative separation zone; (b) isomerizing the butene-1 in an isomerization zone in the presence of an acidic catalyst at from 100° to 350° C.; (c) passing the isomerization mixture obtained from the isomerization zone into a distillation separation zone; (d) removing a butene-1-containing fraction which additionally contains trans-butene-2 above the lower third of the distillative separation zone, and passing it to the isomerization zone; (e) removing at the same time an n-butane-containing fraction from the distillative separation section at a point above the lower third of the distillative separation zone; and (f) removing the butenes-2 or a fraction containing these in the lower third of the distillative separation zone.
Claim 3
Dependent Claim
16 words
A process as claimed in claim 1, wherein an acidic catalyst is employed for the isomerization.
Claim 4
Dependent Claim
15 words
A process as claimed in claim 1, wherein phosphoric acids and/or phosphates-containing catalysts are used.
Claim 5
Dependent Claim
21 words
A process as claimed in claim 1, wherein the catalyst used is one which contains a zeolite of the pentasil type.
Claim 6
Dependent Claim
16 words
A process as claimed in claim 1, wherein a catalyst containing an aluminosilicate zeolite is used.
Claim 7
Dependent Claim
16 words
A process as claimed in claim 1, wherein a catalyst containing a borosilicate zeolite is used.
Claim 8
Dependent Claim
17 words
A process as claimed in claim 1, wherein a catalyst containing an iron silicate zeolite is used.
Claim 9
Dependent Claim
18 words
A process as claimed in claim 1, wherein the catalyst used is a zeolite doped with transition metals.
Claim 10
Dependent Claim
18 words
A process as claimed in claim 1, wherein the catalyst used is a zeolite doped with noble metals.
Claim 11
Dependent Claim
17 words
A process as claimed in claim 1, wherein a catalyst doped with rare earth metals is used.
Claim 12
Dependent Claim
16 words
A process as claimed in claim 9, wherein a palladium-doped zeolite is used as the catalyst.
Claim 13
Dependent Claim
18 words
A process as claimed in claim 1, wherein the isomerization is carried out in the presence of hydrogen.
Claim 14
Dependent Claim
44 words
A process as claimed in claim 1, wherein the amount of transbutene-2 recycled to the isomerization zone in step (d) is such that the weight ratio of trans-butene-2 recycled to the isomerization zone to n-butane removed in step (d) is from 100:1 to 1:100.