Process for producing propylene oxide

a propylene oxide and process technology, applied in the direction of organic chemistry, etc., can solve the problems of high cost, inability to meet the specific requirements of removing oxygen, and in the prior art description of catalysts, etc., to reduce the oxygen comprised

Inactive Publication Date: 2007-01-04
BASF AG +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0028] (III) reducing the oxygen comprised in mixture (GII) at least partially by reaction with hydrogen in the presence of a catalyst comprising Sn and at least one noble metal.

Problems solved by technology

On the other hand, the prior art describes catalysts which do not meet the specific requirements of removing oxygen from gas mixtures obtained in epoxidation reactions such as epoxidation of propene.
Moreover, adsorption techniques described in the prior art have the major disadvantage that during adsorption, the explosive range of propene / oxygen mixtures is passed due to to the increasing concentration of absorbed oxygen.
Consequently, in order to avoid process risks, apparatuses used for adsorption techniques have to be constructed highly pressure resistant, thus causing high costs which in turn render the overall process economically undesirable.

Method used

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  • Process for producing propylene oxide
  • Process for producing propylene oxide
  • Process for producing propylene oxide

Examples

Experimental program
Comparison scheme
Effect test

example 1

Preparation of a Catalyst According to the Invention

[0297] As support, alpha-alumina spheres were used which are commercially available (Spheralite 512 G from Axens, France).

[0298] 225 g of these alumina spheres were impregnated with 86 ml of a solution of 0.3134 g of platinum nitrate having a platinum content of 57.52 wt.-%. After 2 h, the impreganted catalyst support was dried at 120° C. The dried catalyst was subsequently impregnated with 77 ml of a solution of 0.3427 g of tin (II) chloride dihydrate. The catalyst was then dried at 120° C. and calcined at 500° C. for 3 h. The thus obtained catalyst had the following composition:

alpha-alumina:99.84 wt.-%platinum: 0.08 wt.-%tin: 0.08 wt.-%

example 2

Epoxidation of Propene

[0299] A stream consisting of 54.5 g / h chemical grade propylene (98 wt.-%) was epoxidized with 74.7 g / h crude aqueous hydrogen peroxide (40 wt.-%) in the presence of a methanol stream (299 g / h) at a pressure of 20 bar. Epoxidation was carried out in the presence of 100 g TS-1 catalyst. The yield of propylene oxide, based in hydrogen peroxide, was 93.2% at a hydrogen peroxide converision of 99.8%.

[0300] Separation of the light components, methanol and water from the main reaction product was performed in a distillation tower having 40 trays. At a top pressure of 1.1 bar, a top stream of the distillation tower was obtained giving a stream (17.5 g / h) containing 83 wt.-% propane, 12 wt.-% propane, 0.6 wt.-% oxygen, 3.3 wt.-% methanol, and 1 wt.-% water. Propylene oxide, methanol and water were taken from the bottom of the distillation tower.

[0301] The repetition of the same experiment using polymer grade propylene resulted in a stream (15.9 g / h) containing 91.2...

example 3

Reaction of Mixture (GII) Obtained According to Example 2 Using the Catalyst According to Example 1

[0302] A stream obtained according to example 2 was compressed to a pressure of 16 bar. At this pressure, condensation at 40° C. was performed giving a liquid and a gaseous stream. The gaseous stream contained 2.8 vol.-% oxygen, 95.3 vol.-5 propene, 0.6 vol.-% propane, 0.7 vol.-% methanol and 0.5 vol.-% water.

[0303] This stream (238.5 Nl / h) was subjected to hydrogenation at a temperature of 300° C. and a pressure of 12 bar using a hydrogen stream (22.7 Nl / h) in a fixed-bed reactor containing 100 g catalyst according to example 1.

[0304] An oxygen conversion of at least 99.6% was achieved, corresponding to an oxygen content of the reactor effluent of at most 100 ppm. Hydrogen conversion was above 97.5 5, propene conversion was 5.4%. The yield with respect to propane was 5.3%, the yield with respect to COx compounds 0.1%.

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Abstract

The present invention relates to a process for producing propylene oxide comprising (I) reacting propene with hydrogen peroxide in the presence of a catalyst to give a mixture (GI) comprising propylene oxide, unreacted propene, and oxygen; (II) separating propylene oxide from mixture (GI) to give a mixture (GII) comprising propene and oxygen; (III) reducing the oxygen comprised in mixture (GII) at least partially by reaction with hydrogen in the presence of a catalyst comprising Sn and at least one noble metal.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a process for producing propylene oxide by epoxidation of propene with hydrogen peroxide in the presence of a catalyst, wherein a mixture (GII) obtained in the process which comprises propene and oxygen is subjected to a reduction reaction in which at least a portion of said oxygen comprised in (GII) is reacted with hydrogen in the presence of a specific catalyst, said catalyst comprising tin and at least one noble metal. BACKGROUND OF THE INVENTION [0002] DE 101 55 470 A1 describes a method for the synthesis of propylene oxide by epoxidation of propene with recovery of unreacted propene, in which propene is recovered from at least a portion of an off-stream of the propylene oxide synthesis by (i) addition of nitrogen to the off-gas stream, (ii) compression and (iii) condensation of the resulting stream, (iv) subjecting the stream to gas permeation and (v) separation. During condensation, a gas stream comprising propene,...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C07D301/12
CPCC07D301/12
Inventor SCHINDLER, GOTZ-PETERWALSDORFF, CHRISTIANKORNER, REINHARDGOBBEL, HANS-GEORG
Owner BASF AG
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