US 5,326,925 AGranted

Isomerization process for 2,3-dimethylbutane production

AssigneeUop LLC

InventorJ. W. Adriaan Sachtler

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Abstract

An isomerization process maximizes the production of 2,3-dimethylbutane by using an arrangement of two reaction zones that operate at low conversion conditions to maximize the production of a methyl pentane containing intermediate and limit the interconversion of 2,3-dimethylbutane to 2,2-dimethylbutane. The process converts a feed comprising normal hexane in a first reaction zone. The effluent from the first reaction zone has a high concentration of methyl pentanes which is separated from normal hexane and passed to a second separation section that receives the effluent from a second reaction zone. Methyl pentanes from the first and second reaction zone effluents enter the second reaction zone for conversion to dimethylbutane in a high 2,3-dimethylbutane to 2,2-dimethylbutane ratio. In this manner the process produces a principally dimethylbutane product having a relatively high octane rating as a result of the high 2,3-dimethylbutane concentration.

Claims17

Dependent claims

A process for the isomerization of a feedstream comprising C.sub.6 hydrocarbons, said process comprising:

(a) contacting said feedstream comprising said C.sub.6 hydrocarbons with an isomerization catalyst at isomerization conditions including a temperature of from 40.degree.-300.degree. C., a pressure of from 4 to 70 barsg and a Liquid Hourly Space Velocity of from 1 to 40 hrs.sup.-1 in a first reaction zone to convert normal hexane to methyl pentanes and recovering a first reaction zone effluent;
(b) separating at least a portion of said first reaction zone effluent into a first recycle stream comprising normal hexane and an intermediate feedstream comprising methyl pentanes;
(c) contacting a combined feed comprising said intermediate feedstream and a second recycle stream comprising methyl pentanes with an isomerization catalyst at isomerization condition including a temperature of from 0.degree.-300.degree. C., a pressure of from 4 to 70 barsg, and a Liquid Hourly Space Velocity of from 1 to 100 hrs.sup.-1 in a second reaction zone to convert methyl pentanes to 2,3-dimethylbutane and recovering a second reaction zone effluent;
(d) separating at least a portion of said second reaction zone effluent into a product stream comprising dimethylbutanes and said second recycle stream comprising methyl pentanes;
and
(e) recovering said product stream from said process.

3 more elements

A process for the isomerization of a feedstream comprising C.sub.6 hydrocarbons, said process comprising:

(a) contacting said feedstream comprising said C.sub.6 hydrocarbons with an isomerization catalyst at isomerization conditions including a temperature of from 40.degree.-300.degree. C., a pressure of from 4 to 70 barsg, and a liquid Hourly Space Velocity of from 5 to 30 hrs.sup.-1 in a first reaction zone to convert normal hexane to methyl pentanes and recovering a first reaction zone effluent;
(b) passing said first reaction zone effluent to a first separation section and recovering a recycle stream comprising normal hexane and an intermediate separation stream comprising the remainder of said first reaction zone effluent from said second separation section;
(c) passing said intermediate separation stream and a second reaction zone effluent stream to a second separation section and recovering an intermediate feedstream comprising methyl pentanes and a product stream comprising dimethylbutanes in a ratio of 2,3-DMB to 2,2-DMB of at least 0.3 from said second separation section;
(d) contacting said intermediate feedstream with an isomerization catalyst at isomerization conditions including a temperature of from 0.degree.-300.degree. C., a pressure of from 4 to 70 barsg, and a Liquid Hourly Space Velocity of from 10 to 60 hrs.sup.-1 in a second reaction zone to convert methyl pentanes to dimethylbutane and recovering said second reaction zone effluent;
(e) recovering said product stream from said isomerization zone.

2 more elements

Dependencies are inferred from the claim text.