Alkylene oxide catalyst and use thereof

Patent metadata

Field	Value
Publication number	US-10159961-B2
Application number	US-201213624131-A
Country	US
Kind code	B2
Filing date	Sep 21, 2012
Priority date	Apr 18, 2006
Publication date	Dec 25, 2018
Grant date	Dec 25, 2018

Abstract

A supported silver catalyst and use thereof in a process for producing an alkylene oxide, such as ethylene oxide, by the direct oxidation of an alkylene with oxygen or an oxygen-containing gas, wherein the catalyst provides improved stability and improved resilience to reactor upsets and timely recovery to substantially pre-upset levels of catalyst activity and/or efficiency. In some embodiments, the catalyst also exhibits improved activity. A catalyst capable of producing ethylene oxide at a selectivity of at least 87 percent while achieving a work rate of at least 184 kg/h/m 3 at a temperature of no greater than 235° C. when operated in a process where the inlet feed to a reactor containing the catalyst comprises ethylene, oxygen, and carbon dioxide, wherein the concentration of carbon dioxide in the inlet feed is greater than or equal to 2 mole percent.

First claim

What is claimed is:

1. A supported silver catalyst prepared on an alumina-containing carrier, the carrier comprising greater than about 95 weight percent alpha-alumina and less than about 30 parts per million acid-leachable alkali metals by weight, the weight percent of the alumina and the concentration of the acid-leachable alkali metals being calculated on the weight of the carrier, wherein the acid-leachable alkali metals are selected from lithium, sodium, potassium, and mixtures thereof, the carrier having deposited thereon:
(A) silver in an amount greater than about 25 weight percent, based on the weight of the catalyst;
(B) cesium as a first promoter in an amount from about 200 ppm to about 1200 ppm by weight;
(C) sodium in an amount from about 10 ppm to about 150 ppm by weight;
(D) lithium in an amount from about 10 ppm to about 100 ppm by weight, and optional additional solid promoters;
the concentrations of the deposited sodium, lithium, and optional additional solid promoters being calculated on the weight of the catalyst.

2. The supported silver catalyst of claim 1 , wherein the alpha-alumina carrier consists essentially of greater than about 98 weight percent alpha-alumina and less than about 30 ppm acid-leachable lithium, sodium, and potassium by weight; the weight percent of the alumina and the concentration of the acid-leachable alkali metals being calculated on the weight of the carrier; and the carrier further has deposited thereon manganese in an amount from about 20 ppm to about 200 ppm by weight; and a promoting amount of sulfur compound and, optionally, rhenium, tungsten, molybdenum, or mixtures thereof, wherein the ratio of 2(moles sulfur plus moles tungsten plus moles molybdenum) plus moles rhenium divided by the total moles cesium and sodium [(2(S+W+Mo)+Re)/(Cs+Na)] ranges from greater than about 0.5/1 to about 1.5/1.

3. The supported silver catalyst of claim 1 , further comprising a promoting amount of sulfur compound and, optionally, rhenium, tungsten, molybdenum, or mixtures thereof, wherein the ratio of 2(moles sulfur plus moles tungsten plus moles molybdenum) plus moles rhenium divided by the total moles cesium and sodium [(2(S+W+Mo)+Re)/(Cs+Na)] ranges from greater than about 0.5/1 to about 1.5/1.

4. The supported silver catalyst of claim 1 , wherein the catalyst comprises a synergistic combination of cesium, sodium, and lithium when used as a catalyst for the production of ethylene oxide.

5. The supported silver catalyst of claim 1 further comprising a promoting amount of rhenium.

6. The supported silver catalyst of claim 1 further comprising a promoting amount of manganese.

7. The supported silver catalyst of claim 1 further comprising a promoter selected from compounds of sulfur, molybdenum, tungsten, and mixtures thereof.

8. The supported silver catalyst of claim 2 , wherein the amount of manganese is at least about 1.5 micromoles per gram of catalyst.

9. The supported catalyst of claim 1 wherein the alumina-containing support comprises particles of alpha-alumina each of which has at least one substantially flat major surface having a lamellate or platelet morphology which approximates the shape of a hexagonal plate, at least 50 percent of which (by number) have a major dimension of less than about 50 microns.

10. The supported silver catalyst of claim 2 wherein the catalyst is capable of producing ethylene oxide at a selectivity of at least 87 percent while achieving a work rate of at least 184 kg/h/m 3 of catalyst at a temperature of no greater than 235° C. when operated in a process using a reactor containing the catalyst, the reactor being provided with an inlet feed and having withdrawn therefrom an outlet stream, where the inlet feed to a reactor containing the catalyst comprises ethylene, oxygen, and carbon dioxide, wherein the concentration of carbon dioxide in the inlet feed is greater than or equal to 2 mole percent.

11. The supported silver catalyst of claim 2 , wherein the catalyst is capable of producing ethylene oxide at a selectivity of at least 87 percent while achieving a work rate of at least 184 kg/h/m 3 of catalyst at a temperature of no greater than 240° C. when operated in a process using a reactor containing the catalyst, the reactor being provided with an inlet feed and having withdrawn therefrom an outlet stream, where the inlet feed to the reactor comprises ethylene, oxygen, and carbon dioxide, wherein the concentration of carbon dioxide in the inlet feed is greater than or equal to 2 mole percent and at least a portion of the carbon dioxide has been recycled from the outlet stream of the reactor.

12. A process for producing a supported silver catalyst, the process comprising:
(a) providing an alumina-containing carrier, the carrier comprising greater than about 95 weight percent alpha-alumina and less than about 30 parts per million acid-leachable alkali metals by weight, the weight percent of the alumina and the concentration of the acid-leachable alkali metals being calculated on the weight of the carrier, wherein the acid-leachable alkali metals are selected from lithium, sodium, potassium, and mixtures thereof; and
(b) depositing on the carrier:
(A) silver in an amount greater than about 25 weight percent, based on the weight of the catalyst;
(B) cesium as a first promoter in an amount from about 200 ppm to about 1200 ppm by weight;
(C) sodium in an amount from about 10 ppm to about 150 ppm by weight;
(D) lithium in an amount from about 10 ppm to about 100 ppm by weight, and optionally, additional solid promoters; the concentrations of the deposited sodium lithium and optional additional solid promoters being calculated on the weight of the catalyst.

Assignees

• Natal Manuel A W
• Bhasin Madan M
• Soo Hwaili
• Liu Albert C
• Dow Global Technologies Llc

Inventors

• Natal Manuel A W
• Bhasin Madan M
• Soo Hwaili
• Liu Albert C

Classifications

• B01J23/58

  with alkali- or alkaline earth metals · CPC title

• B01J23/688

  with manganese, technetium or rhenium · CPC title

• B01J35/006

  Operations & Transport · mapped topic

• B01J37/0203

  the impregnation liquid containing organic compounds · CPC title

• Y02P20/52

  using catalysts, e.g. selective catalysts · CPC title