Methods of Preparing a Catalyst with Low HRVOC Emissions
A method of preparing a catalyst comprising a) drying a chrominated-silica support followed by contacting with a titanium(IV) alkoxide to form a metalized support, b) drying a metalized support followed by contacting with an aqueous alkaline solution comprising from about 3 wt. % to about 20 wt. % of a nitrogen-containing compound to form a hydrolyzed metalized support, and c) drying the hydrolyzed metalized support followed by calcination at a temperature in a range of from about 400° C. to about 1000° C. and maintaining the temperature in the range of from about 400° C. to about 1000° C. for a time period of from about 1 minute to about 24 hours to form the catalyst.
1 . A method of preparing a hydrolyzed pre-catalyst comprising:
a) drying a silica support by heating the silica support to a temperature in a range of from about 150° C. to about 250° C. and maintaining the temperature of the silica support in the range of from about 150° C. to about 250° C. for a time period of from about 1 hour to about 24 hours to form a dried support;
b) contacting the dried support and a titanium-containing compound comprising a titanium(IV) alkoxide to form a titanated support;
c) drying the titanated support by heating the titanated support to a temperature in a range of from about 50° C. to about 200° C. and maintaining the temperature of the titanated support in the range of from about 50° C. to about 200° C. for a time period of from about 30 minutes to about 6 hours to form a dried titanated support;
d) contacting the dried titanated support and a gas-phase mixture comprising an aqueous alkaline solution comprising from about 3 wt. % to about 20 wt. % of a nitrogen-containing compound for a time period of from about 10 minutes to about 6 hours to form a mixture comprising a hydrolyzed titanated support wherein an amount of the aqueous alkaline solution utilized is sufficient to provide an equivalent molar ratio of the nitrogen-containing compound to the titanium-containing compound in a range of from about 100:1 to about 1:2; and
e) removing the hydrolyzed titanated support from the mixture comprising the hydrolyzed titanated support and drying the hydrolyzed titanated support by heating the hydrolyzed titanated support to a temperature in a range of from about 50° C. to about 200° C. and maintaining the temperature of the hydrolyzed titanated support in the range of from about 50° C. to about 200° C. for a time period of from about 30 minutes to about 6 hours to form a hydrolyzed pre-catalyst.
2 . The method of claim 1 , wherein the titanium(IV) alkoxide comprises titanium(IV) isopropoxide.
3 . The method of claim 1 , wherein the titanium-containing compound is present in an amount of from about 0.01 wt. % to about 10.0 wt. % based on the total weight of the pre-catalyst composition.
4 . The method of claim 1 , wherein the aqueous alkaline solution comprises a vapor.
5 . The method of claim 4 , wherein the aqueous alkaline solution comprises methanol, ethanol, n-propanol, isopropanol, or a combination thereof.
6 . The method of claim 1 , wherein the nitrogen-containing compound comprises an amide, an amidine, an amine, a diamine, a triamine, an amino acid, an ammonium hydroxide, a formamide, a hydrazine, a hydroxylamine, an imidazole, a piperazine, a piperidine, a pyrazine, a pyrazole, a pyridine, a pyrimidine, a pyrrole, a urea, or a combination thereof.
7 . The method of claim 1 , wherein a volumetric ratio of the aqueous alkaline solution further comprises a basic liquid and a vapor.
8 . The method of claim 7 , wherein the basic liquid, the vapor or both has a temperature in the range of from about 120° C. to about 200° C.
9 . A method of preparing a catalyst comprising:
a) drying a silica support by heating the silica support to a temperature in a range of from about 150° C. to about 250° C. and maintaining the temperature of the silica support in the range of from about 150° C. to about 250° C. for a time period of from about 1 hour to about 24 hours to form a dried support;
b) contacting the dried support and a titanium-containing compound comprising a titanium(IV) alkoxide to form a titanated support;
c) drying the titanated support by heating the titanated support to a temperature in a range of from about 50° C. to about 200° C. and maintaining the temperature of the titanated support in the range of from about 50° C. to about 200° C. for a time period of from about 30 minutes to about 6 hours to form a dried titanated support;
d) contacting the dried titanated support and a gas-phase mixture comprising an aqueous alkaline solution comprising from about 3 wt. % to about 20 wt. % of a nitrogen-containing compound for a time period of from about 10 minutes to about 6 hours to form a mixture comprising a hydrolyzed titanated support wherein an amount of the aqueous alkaline solution utilized is sufficient to provide an equivalent molar ratio of the nitrogen-containing compound to the titanium-containing compound in a range of from about 100:1 to about 1:2;
e) removing the hydrolyzed titanated support from the mixture comprising the hydrolyzed titanated support and drying the hydrolyzed titanated support by heating the hydrolyzed titanated support to a temperature in a range of from about 50° C. to about 200° C. and maintaining the temperature of the hydrolyzed titanated support in the range of from about 50° C. to about 200° C. for a time period of from about 30 minutes to about 6 hours to form a hydrolyzed pre-catalyst; and
f) calcining the hydrolyzed pre-catalyst by heating to a temperature in a range of from about 400° C. to about 1000° C. to form the catalyst.
10 . The method of claim 9 , wherein the titanium(IV) alkoxide comprises titanium(IV) isopropoxide.
11 . The method of claim 9 , wherein the titanium-containing compound is present in an amount of from about 0.01 wt. % to about 10.0 wt. % based on the total weight of the catalyst.
12 . The method of claim 9 , wherein the nitrogen-containing compound comprises an amide, an amidine, an amine, a diamine, a triamine, an amino acid, an ammonium hydroxide, a formamide, a hydrazine, a hydroxylamine, an imidazole, a piperazine, a piperidine, a pyrazine, a pyrazole, a pyridine, a pyrimidine, a pyrrole, a urea, or a combination thereof.
13 . The method of claim 9 , wherein the calcining is carried out by heating to a temperature in a range of from about 500° C. to about 800° C.
14 . The method of claim 9 , wherein the calcining is carried out for a time period of from about 1 minute to about 24 hours.
15 . The method of claim 9 , wherein an amount of highly reactive volatile organic compounds emitted during calcining of the hydrolyzed pre-catalyst is reduced by from about 80% to about 95% , as determined by combustion analysis in accordance with EPA Method 18-type/ASTM D1946, when compared to the amount of highly reactive volatile organic compounds emitted during calcining an otherwise similar hydrolyzed pre-catalyst prepared in the absence of an alkaline material.
16 . The method of claim 9 , wherein an amount of the highly reactive volatile organic compounds emitted during calcining of the hydrolyzed pre-catalyst is less than about 1 wt. % as determined by combustion analysis in accordance with EPA Method 18-type/ASTM D1946.
17 . The method of claim 9 , wherein the aqueous alkaline solution comprises a vapor associated with a basic liquid wherein the basic liquid comprises an aqueous solution of the nitrogen-containing compound and optionally an alcohol wherein an amount of the nitrogen-containing compound in the aqueous solution is from about 3 wt. % to about 20 wt. % wherein a volumetric ratio of the aqueous solution to the alcohol is from about 7:3 to about 3:7 and wherein the alcohol is methanol, ethanol, n-propanol, isopropanol, or a combination thereof.
18 . The method of claim 17 , wherein the alcohol comprises methanol.
19 . The method of claim 17 , wherein the nitrogen-containing compound comprises an ammonium hydroxide.
20 . An ethylene polymer formed from the catalyst of claim 9 .