US 5,763,730 A · Process for alkane isomerization using reactive chromatography

Abstract

A process for the continuous isomerization of an alkane to produce an isomerized product through contacting the alkane with a simulated moving bed acting as a catalyst for isomerization and an adsorbent for the alkanes has been developed. The alkane may be n-butane and the isomerized product 2-methylpropane, the alkane may be n-pentane and the isomerized product 2-methylbutane or 2,2-dimethylpropane, the alkane may have from 6 up to about 8 carbon atoms with no more than one methyl branch and the isomerized product having the same number of carbon atoms and at least two methyl branches, or the reactant may be a mixture of the foregoing alkanes with the corresponding isomerized products being formed. In a zone of the simulated moving bed, the alkanes are catalytically isomerized to form the isomerized products. The unreacted alkanes are adsorbed, and the isomerized products are collected. In a subsequent zone of the simulated moving bed, the unreacted alkanes are desorbed using a desorbent and may be catalytically isomerized to form additional isomerized products which are also separated and collected. The catalyst used in the simulated moving bed may be platinum on tungstated zirconia, and the adsorbent used in the simulated moving bed may be EU-1, ZSM-12, SAPO-5, Y-82, faujasite, erionite, zeolite beta exchanged with sodium, lithium, potassium, barium, calcium, strontium or combinations thereof, zeolite X exchanged with calcium and strontium, mordenite exchanged with sodium, lithium, potassium, barium, calcium, strontium, or combinations thereof.

Claims32

Dependent claims

A process for the gas phase isomerization of an alkane to an isomerized product, wherein

i) said alkane is n-butane and the isomerized product is 2-methylpropane, or
ii) said alkane is n-pentane and the isomerized product is 2-methylbutane or 2,2-dimethylpropane, or
iii) said alkane has from 6 up to about 8 carbon atoms with no more than one methyl branch and the isomerized product has at least two methyl branches,
said process comprising:
a. continuously introducing, under conditions effective to isomerize the alkane to the isomerized product, the alkane and a desorbent into a simulated moving bed of a mixture of solids wherein the mixture of solids contains a catalyst effective to isomerize the alkane and an adsorbent effective to selectively adsorb the alkane relative to the isomerized product;
b. isomerizing at least a portion of the alkane to at least one isomerized product in a zone of the simulated moving bed with concurrent separation of the isomerized products formed using the adsorbent;
c. desorbing the alkane from the adsorbent using the desorbent in a subsequent zone of the simulated moving bed;
and
d. removing and collecting the isomerized products from the simulated moving bed.

6 more elements

A process for the gas phase isomerization of an alkane to an isomerized product, wherein

i) said alkane is n-butane and the isomerized product is 2-methylpropane, or
ii) said alkane is n-pentane and the isomerized product is 2-methylbutane or 2,2-dimethylpropane, or
iii) said alkane has from 6 up to about 8 carbon atoms with no more than one methyl branch and the isomerized product has at least two methyl branches,
said process comprising:
a. continuously introducing, under conditions effective to isomerize the alkane to the isomerized product, the alkane and a desorbent into a simulated moving bed of a mixture of solids wherein the mixture of solids contains a catalyst effective to isomerize the alkane and an adsorbent effective to selectively adsorb the alkane relative to the isomerized product, said adsorbent selected from the group consisting of EU-1, ZSM-12, SAPO-5, Y-82, faujasite, erionite, zeolite beta exchanged with sodium, lithium, potassium, barium, calcium, strontium and combinations thereof, zeolite X exchanged with calcium and strontium, and mordenite exchanged with sodium, lithium, potassium, barium, calcium, strontium, and combinations thereof;
b. isomerizing at least a portion of the alkane to at least one isomerized product in a zone of the simulated moving bed with concurrent separation of the isomerized products formed using the adsorbent;
c. desorbing the alkane from the adsorbent using the desorbent in a subsequent zone of the simulated moving bed;
and
d. removing and collecting the isomerized products from the simulated moving bed.

6 more elements

Dependencies are inferred from the claim text.

Process for alkane isomerization using reactive chromatography

Life of this patent

Process for alkane isomerization using reactive chromatography

Life of this patent

Abstract

Claims32