Aging of chromium-containing gel at high pH

Claim 2

A process comprising: forming a co-gelled silica-chromium hydrogel; aging said hydrogel for a time of at least one hour; maintaining a pH of said hydrogel during at least a major portion of said aging at a value within the range of 7 to 9; and treating said hydrogel with a volatile liquid organic compound to remove water and thus convert said hydrogel to a xerogel, said chromium being present in an amount to give 0.001 to 10 weight percent chromium based on the weight of said xerogel.

Claim 3

A method according to claim 1 wherein said pH is maintained within the range of 7 to 9 by means of adding a basic material to said hydrogel.

Claim 4

A method according to claim 2 wherein said basic material is one of ammonia or ammonium hydroxide.

Claim 5

A method according to claim 2 wherein said basic material is added prior to said aging.

Claim 6

A method according to claim 2 wherein said volatile liquid organic compound is an alcohol.

Claim 7

A method according to claim 5 wherein said alcohol is one of 1-pentanol, 3-methyl-1-butanol, or 1-hexanol.

Claim 8

A method according to claim 1 wherein said volatile liquid organic compound is an alcohol.

Claim 9

A method according to claim 7 wherein said alcohol is one of 1-pentanol, 3-methyl-1-butanol, or 1-hexanol.

Claim 10

A method according to claim 1 wherein said pH is maintained at said value of 7 to 9 by means of utilizing a coordination chromium compound having a nitrogen-containing group.

Claim 11

A method according to claim 9 wherein said chromium compound is chloropentamine chromium(III) chloride.

Claim 12

A method according to claim 1 wherein said hydrogel is formed by adding a solution of sodium silicate into acid containing a chromium compound.

Claim 13

A method according to claim 11 wherein said aging is carried out at a temperature within the range of 65° F. (18° C.) to 200° F. (93° C.) for a time within the range of one hour to 20 hours.

Claim 14

A method according to claim 1 comprising in addition heating said xerogel in an oxygen containing ambient at a temperature within the range of 800° F. (425° C.) to 2000° F. (1095° C.) to activate same.

Claim 15

A catalyst produced by the method of claim 1.

Claim 16

A process comprising: forming a silica, titania, chromium tergel hydrogel, said chromium coming from a coordination chromium compound having a nitrogen-containing group; aging said hydrogel for at least one hour; and treating said hydrogel with a volatile liquid organic compound to remove water and thus convert said hydrogel to a xerogel.

Claim 17

A process comprising: forming a silica, titania, chromium tergel hydrogel, said chromium coming from a coordination chromium compound having a nitrogen-containing group; aging said hydrogel for at least one hour; and treating said hydrogel with a volatile liquid organic compound to remove water and thus convert said hydrogel to a xerogel.

Claim 18

A method according to claim 15 wherein said volatile organic liquid is an alcohol.

Claim 19

A method according to claim 15 wherein said alcohol is one of 1-pentanol, 3-methyl-1-butanol, or 1-hexanol.

Claim 20

A method according to claim 15 wherein said chromium compound is selected from hexamminechromium(III) nitrate and chloropentamine chromium(III) chloride.

Claim 21

A method according to claim 15 wherein said hydrogel is formed by adding a solution of sodium silicate into acid containing a titanium compound and said chromium compound.

Claim 22

A method according to claim 19 wherein said aging is carried out at a temperature within the range of 65° F. (18° C.) to 200° F. (93° C.) for a time within the range of one hour to 20 hours.

Claim 23

A catalyst produced by the method of claim 15.

Claim 24

A method according to claim 1 wherein said chromium is present in an amount within the range of 0.1 to 5 weight percent based on the weight of said xerogel.

Claim 25

A method according to claim 15 wherein said chromium is present in an amount within the range of 0.001 to 10 weight percent based on the weight of said xerogel.

Claim 26

A method according to claim 15 wherein said chromium is present in an amount within the range of 0.1 to 5 weight percent based on the weight of said xerogel.

Claim 27

A method according to claim 15 wherein said chromium compound is selected from (a) compounds of the formula CrX 3 .yNH 3 where X is a halogen ion selected from Cl - , Br - , I 31 and y is an integer ranging from 1 to 6; (b) chromammines containing 6 neutral groups of the formula [CrA 6 ]Z 3 in which A is selected from NH 3 , ethylenediamine and unsymmetrical propylenediamine provided further that a portion of A can be H 2 O and Z is an acid radical selected from Cl - , Br - , I - , NO 3 - , SO 4 -2 and PO 4 -3; (c) chromammine compounds containing 5 neutral groups of the formula: [CrA 5 Y]Z 2 where A and Z are as before and Y is a radical from a monobasic acid selected from Cl - , Br - , I - , NO 2 - , NO 3 - , OH - and CNS - ; and (d) chromammine compounds containing 5 neutral groups of the formula [CrA 5 W]V where A is as before, V is Cl - , Br - , I - , (OH) - , and W is a radical from a dibasic acid selected from SO 3 -2 , SO 4 -2 , CO 3 -2 and C 2 O 4 -2 .