Enhanced dispersion of two-dimensional metal oxide surface species on silica using an alkali promoter

Patent metadata

Field	Value
Publication number	US-2016228851-A1
Application number	US-201615016850-A
Country	US
Kind code	A1
Filing date	Feb 5, 2016
Priority date	Feb 6, 2015
Publication date	Aug 11, 2016
Grant date	—

Abstract

Improved catalysts including two-dimensional metal oxide species highly dispersed on a silica support are disclosed, as well methods of making and using such catalysts. The catalysts are substantially free of metal oxide nanoparticles. The higher than expected maximum dispersion densities are obtained in the catalysts by introducing dispersion-promoting sodium ions, and optionally, aluminum ions, onto the silica support. The improved catalysts may be used in a variety of chemical processes, including, without limitation, in dehydrogenation, oxidation, and metathesis reactions.

First claim

We claim:

1 . A heterogeneous catalyst comprising one or more two-dimensional metal oxide species highly dispersed on the surface of a silica support that further comprises ions of one or more alkali metals, wherein the metal oxide is an oxide of a group 3, group 4, group 5, group 6 or group 7 metal, and wherein the catalyst is substantially free of metal oxide nanoparticles.

2 . The heterogeneous catalyst of claim 1 , wherein the mole ratio of the alkali metal ions present to the metal atoms of the metal oxide present is less than 0.25/1.

3 . The heterogeneous catalyst of claim 1 , wherein the one or more two-dimensional metal oxide species are monomeric species.

4 . The heterogeneous catalyst of claim 1 , wherein the one or more two-dimensional metal oxide species exhibit tetrahedral geometry around the metal atoms.

5 . The heterogeneous catalyst of claim 1 , wherein the metal oxide is an oxide of a group 5, group 6 or group 7 metal.

6 . The heterogeneous catalyst of claim 5 , wherein the metal oxide is an oxide of a group 5 or group 6 metal.

7 . The heterogeneous catalyst of claim 6 , wherein the metal oxide is an oxide of a group 5 metal.

8 . The heterogeneous catalyst of claim 1 , wherein the metal oxide is selected from the group consisting of aluminum oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, rhenium oxide, titanium oxide, and mixtures thereof.

9 . The heterogeneous catalyst of claim 8 , wherein if vanadium oxide is selected, it is dispersed on the surface of the silica support in the range of 3.2-10 V-atoms/nm 2 ; if niobium oxide is selected, it is dispersed on the surface of the silica support in the range of 1.2-6 Nb-atoms/nm 2 ; and if tantalum oxide is selected, it is dispersed on the surface of the silica support in the range of 1-6 Ta-atoms/nm 2 .

10 . The heterogeneous catalyst of claim 1 , wherein the ions of one or more alkalai metals are sodium ions.

11 . The heterogeneous catalyst of claim 10 , wherein the sodium ions are present in the silica support at a concentration of about 0.15-1.4 Na− ions/nm 2 .

12 . The heterogeneous catalyst of claim 10 , wherein the sodium ions are present in the silica support at a concentration of about 0.3-1.0 Na− ions/nm 2 .

13 . The heterogeneous catalyst of claim 10 , wherein the sodium ions are present in the silica support at a concentration of about 0.4-0.8 Na− ions/nm 2 .

14 . The heterogeneous catalyst of claim 10 , wherein the sodium ions are present in the silica support at a concentration of about 0.6 Na− ions/nm 2 .

15 . A method of making a desired chemical product, comprising contacting a liquid or gaseous reactant with the heterogeneous catalyst of claim 1 , whereby the desired chemical product is formed by a process catalyzed by the heterogeneous catalyst.

16 . The method of claim 15 , wherein the liquid or gaseous reactant is an alkane, the process catalyzed by the heterogeneous catalyst is:
(a) oxidative dehydrogenation, and the desired chemical product is an olefin; (b) non-oxidative dehydrogenation, and the desired chemical product is an olefin; or (c) alkane oxidation, and the desired chemical product is an oxygenate.

17 . The method of claim 15 , wherein the liquid or gaseous reactant comprises one or more olefins, the process catalyzed by the heterogeneous catalyst is olefin metathesis, and the desired chemical product comprises one or more olefins that are different than the olefins of which the liquid or gaseous reactant is comprised.

18 . The method of claim 15 , wherein the liquid or gaseous reactant is a chlorocarbon, the process catalyzed by the heterogeneous catalyst is chlorocarbon degradation, and the desired chemical product comprise products of chlorocarbon degradation.

19 . The method of claim 15 , wherein the liquid or gaseous reactant is glycerol, the process catalyzed by the heterogeneous catalyst is glycerol conversion, and the desired chemical product is acrolein.

20 . A method of making a heterogeneous catalyst comprising one or more two-dimensional metal oxide species highly dispersed on the surface of a silica support, comprising:
(a) contacting a silica support with a solution comprising one or more alkali metal ions, resulting in a silica support having an alkali metal promoter; (b) contacting the silica support having an alkali metal promoter with a composition comprising one or more metal oxides or metal oxide precursors, wherein the metal oxide is an oxide of a group 3, group 4, group 5, group 6 or group 7 metal; whereby one or more two-dimensional metal oxide species are highly dispersed on the surface of the silica support.

21 . The method of claim 20 , wherein the mole ratio of the alkali metal ions recited in step (a) to the metal atoms of the metal oxide recited in step (b) is less than 0.25/1.

22 . The method of claim 20 , wherein the metal oxide is selected from the group consisting of aluminum oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, rhenium oxide, titanium oxide, and mixtures thereof.

23 . The method of claim 20 , wherein the one or more alkali metal ions are sodium ions.

24 . The method of claim 23 , wherein the sodium ions are present in the silica support at a concentration of: about 0.15-1.4 Na− ions/nm 2 ; about 0.3-1.0 Na− ions/nm 2 ; about 0.4-0.8 Na− ions/nm 2 ; or about 0.6 Na− ions/nm 2 .

Assignees

• Wisconsin Alumni Res Found

Inventors

• Hermans Ive
• Grant Joseph Thomas
• Marquez Carlos Carrero

Classifications

• B01J2235/05

  Nuclear magnetic resonance [NMR] · CPC title

• B01J2235/10

  Infrared [IR] · CPC title

• B01J35/80

  characterised by their amorphous structures · CPC title

• B01J2235/00

  Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties · CPC title

• C07C2523/30

  Tungsten · CPC title