Hydrogenation of benzene to cyclohexane
AssigneeCatalytic Distillation Technologies
InventorGary R. Gildert
Life of this patent
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Abstract
A process for the production of cyclohexane by the hydrogenation of benzene is provided wherein the reactor is operated at a pressure wherein the reaction mixture is boiling under low hydrogen partial pressure in the range of about 0.1 psia to less than 200 psia at 0 to 350 psig overhead pressure. The catalyst is provided as a catalytic distillation structure such that the reaction is concurrently occurring with a distillation. The benzene is fed at a point above the bed and the hydrogen is fed below the bed. All of the overheads may be returned as reflux to provide cooling within the catalyst bed.
Claims10
In a process for the production of cyclohexane by the hydrogenation of benzene comprising the steps of:
- (a) feeding a first stream comprising benzene to a distillation column reactor containing a bed of hydrogenation catalyst;
- (b) feeding a second stream comprising hydrogen to said distillation column reactor at a point below said bed;
- (c) contacting the benzene and hydrogen at a hydrogen partial pressure of from 0.1 to 200 psia, in the presence of a hydrogenation catalyst thereby reacting a portion of the benzene with a portion of the hydrogen to form a reaction mixture containing cyclohexane and, unreacted hydrogen and unreacted benzene;
- (d) maintaining the pressure in the distillation column reactor such that a portion of the reaction mixture is boiling;
- (e) removing gaseous overheads, components from the reaction mixture and hydrogen from the distillation column reactor;
- (f) condensing a portion of the overheads from the distillation column reactor;
- and
- (g) returning a portion of the condensed overheads to the distillation column reactor as reflux,
- wherein the improvement comprises feeding said first stream at a point above said bed of hydrogenation catalyst.
In a process for the production of cyclohexane from the hydrogenation of benzene comprising the steps of:
- (a) feeding a first stream comprising benzene to a distillation column reactor containing a bed of hydrogenation catalyst;
- (b) feeding a second stream containing hydrogen to said distillation column reactor at a point below said bed, said hydrogen being at a mole ratio to benzene of between 3.0 and 10.0;
- (c) contacting the benzene and hydrogen at a total overhead pressure in the range of about 75 to 200 psig, a hydrogen partial pressure in the range of 75 to 150 psia and a reaction temperature of between 280-380° F., in the presence of a hydrogenation catalyst prepared in the form of a catalytic distillation structure thereby reacting substantially all of the benzene with a portion of the hydrogen to form a reaction mixture containing cyclohexane and unreacted hydrogen;
- (d) maintaining the pressure in the distillation column reactor such that a portion of the reaction mixture is boiling at the temperature of reaction in said bed;
- (e) removing gaseous benzene, cyclohexane and hydrogen as overheads from the distillation column reactor;
- (f) condensing substantially all of the benzene and cyclohexane removed as overheads from the distillation column reactor;
- (g) returning a substantially all of the condensed benzene and cyclohexane to the distillation column reactor as reflux;
- and
- (h) withdrawing a bottoms liquid product containing cyclohexane from the distillation column,
- wherein the improvement comprises feeding said first stream at a point above said bed of hydrogenation catalyst.
Dependencies are inferred from the claim text.