Chromium-on-alumina dehydrogenation catalysts and methods for preparing and using them

Patent metadata

Field	Value
Publication number	US-11420187-B2
Application number	US-201916672799-A
Country	US
Kind code	B2
Filing date	Nov 4, 2019
Priority date	Nov 13, 2018
Publication date	Aug 23, 2022
Grant date	Aug 23, 2022

Abstract

The present disclosure relates to chromium-on-alumina dehydrogenation catalyst materials, to methods for making such catalysts, and to methods for dehydrogenating hydrocarbons using such catalysts. In one aspect, the disclosure provides a method for preparing a dehydrogenation catalyst material, the method comprising impregnating a chromium-on-alumina material with ascorbic acid, one or more of sodium, lithium and potassium (e.g., sodium), and chromium; and calcining the impregnated material to provide the dehydrogenation catalyst material comprising chromium in the range of 2.5 wt. % to about 35 wt. % and having no more than 100 ppm chromium(VI).

First claim

What is claimed is:

1. A method for preparing a dehydrogenation catalyst material, the method comprising
providing a porous chromium-on-alumina material having at least 1000 ppm Cr(VI);
impregnating the chromium-on-alumina material with an aqueous impregnating solution comprising ascorbic acid, one or more of sodium, lithium and potassium, and chromium; and
calcining the impregnated material to provide the dehydrogenation catalyst material having chromium in the range of 10-35 2.5 wt. % and having no more than 100 ppm chromium(VI).

2. A method according to claim 1 , wherein the chromium-on-alumina catalyst material before the impregnating step comprises at least 50 wt. % alumina, calculated as Al 2 O 3 .

3. A method according to claim 1 , wherein chromium is present in the chromium-on-alumina catalyst material before the impregnating step in an amount within the range of about 2.5 wt. % to about 35 wt. %, calculated as Cr 2 O 3 .

4. A method according to claim 1 , wherein the chromium-on-alumina catalyst material before the ascorbic acid impregnating step comprises at least about 5,000 ppm chromium(VI).

5. A method according to claim 1 , wherein the impregnation is performed by impregnating the porous chromium-on-alumina material with an aqueous impregnation solution comprising
ascorbic acid, present in an amount within the range of about 1 wt. % to about 30 wt. %,
sodium, lithium and/or potassium, present in an amount within the range of about 0.1 wt. % to about 5 wt. % calculated on an oxide basis, and
chromium, present in an amount within the range of about 0.01 wt. % to about 5 wt. % calculated as Cr 2 O 3 .

6. A method according to claim 5 , wherein the ascorbic acid is present in the aqueous impregnation solution in an amount within the range of about 5 wt. % to about 25 wt. %.

7. A method according to claim 5 , wherein chromium is present in the aqueous impregnation solution in an amount within the range of about 0.1 wt. % to about 5 wt. %, calculated as Cr 2 O 3 .

8. A method according to claim 7 , wherein chromium is present in the aqueous impregnation solution in an amount within the range of 0.1 wt. % to 3 wt. %.

9. A method according to claim 1 , wherein the impregnated material is calcined at a temperature within the range of 100° C. to 600° C.

10. A method according to claim 1 , wherein the dehydrogenation catalyst material has no more than 20 ppm chromium(VI) on an elemental mass basis.

11. A method according to claim 1 , wherein the dehydrogenation catalyst material has no more than 10 ppm chromium(VI) on an elemental mass basis.

12. A method according to claim 10 , wherein the porous chromium-on-alumina material has at least 7500 ppm Cr(VI).

13. A method according to claim 11 , wherein the porous chromium-on-alumina material has at least 7500 ppm Cr(VI).

14. A method according to claim 12 , wherein the porous chromium-on-alumina material has 15-35 wt % chromium calculated as Cr 2 O 3 .

Assignees

• Clariant Int Ltd

Inventors

• Fridman Vladimir Z
• Monroe Adam

Classifications

• C07C2523/26

  Chromium · CPC title

• B01J23/26 Primary

  Chromium · CPC title

• B01J37/0203

  the impregnation liquid containing organic compounds · CPC title

• B01J21/04

  Alumina · CPC title

• B01J37/086

  Decomposition of an organometallic compound, a metal complex or a metal salt of a carboxylic acid · CPC title