Process for preparing a catalyst with low hrvoc emissions

Abstract

The present application relates to a process for preparing a catalyst with low HRVOC emissions. A process for preparing a catalyst comprising: a) drying a chromophoric silica support, followed by contacting with a titanium (IV) alkoxide to form a metallized support, b) drying the metallized support, followed by contacting with a basic aqueous solution comprising about 3 wt% to about 20 wt% of a nitrogen-containing compound to form a hydrolyzed metallized support, and c) drying the hydrolyzed metallized support, followed by calcination at a temperature in the range of about 400 °C to about 1000 °C, and maintaining the temperature in the range of about 400 °C to about 1000 °C for a period of time of about 1 minute to about 24 hours to form the catalyst.

Description

[0001] This application is a divisional application. The original application was filed on April 9, 2019, with application number 201980021708.6, and the invention title was "Method for preparing catalysts with low HRVOC emissions," the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to catalyst compositions. More specifically, this disclosure relates to methods for preparing olefin polymerization catalyst compositions and polymers prepared therefrom. Background Technology

[0003] One class of economically important olefin polymerization catalysts includes chromium-silica-titanium catalysts. Enhancements to the preparation methods for olefin polymerization catalysts can reduce the costs associated with catalyst production and improve process economics. For example, highly reactive volatile organic compounds (HRVOCs) may be emitted during catalyst production. HRVOCs play a role in ozone formation in ozone-deficient areas, i.e., areas that do not meet the Environmental Protection Agency's (EPA) air quality standards for ground-level ozone. Therefore, processes that generate HRVOC emissions may need to comply with state and federal regulations regarding HRVOC emissions, such as HRVOC emission caps and trading programs. Therefore, there is an ongoing need to develop processes for producing olefin polymerization catalysts that generate minimal HRVOC emissions. Summary of the Invention

[0004] This article discloses a method for preparing a precatalyst for hydrolysis, comprising: a) drying a silica support by heating it to a temperature in the range of about 150°C to about 250°C and maintaining the temperature in the range of about 150°C to about 250°C for a period of about 1 hour to about 24 hours to form a dried support; b) contacting the dried support with titanium alkoxide (IV) to form a titanate support; c) drying the titanate support by heating it to a temperature in the range of about 50°C to about 200°C and maintaining the temperature in the range of about 50°C to about 200°C for a period of about 30 minutes to about 6 hours to form a dried titanate support; d) contacting the dried titanium... The acidified support is contacted with an alkaline aqueous solution containing about 3 wt% to about 20 wt% of a nitrogen-containing compound for about 10 minutes to about 6 hours to form a mixture containing a hydrolyzed titanate support, wherein the weight ratio of the amount of alkaline aqueous solution to the amount of alkanolate titanium (IV) in the dried titanate support is about 30:1 to about 3:1; and e) the hydrolyzed titanate support is removed from the mixture containing the hydrolyzed titanate support, and the hydrolyzed titanate support is dried by heating to a temperature in the range of about 50°C to about 200°C and maintaining the temperature in the range of about 50°C to about 200°C for about 30 minutes to about 6 hours to form a hydrolyzed precatalyst. The method may further include contacting a chromium-containing compound with the hydrolyzed precatalyst to form a precatalyst, and calcining the precatalyst by heating to a temperature in the range of about 400°C to about 1000°C and maintaining the temperature in the range of about 400°C to about 1000°C for about 1 minute to about 24 hours to form a catalyst.

[0005] This article also discloses a method for preparing a pre-catalyst for hydrolysis, comprising: a) drying a silica support by heating it to a temperature in the range of about 150°C to about 250°C and maintaining the temperature in the range of about 150°C to about 250°C for a period of about 1 hour to about 24 hours to form a dried support; b) contacting the dried support with titanium alkoxide (IV) to form a titanate support; c) heating the titanate support to a temperature in the range of about 50°C to about 200°C and maintaining the temperature in the range of about 50°C to about 200°C while contacting the titanate support with an alkaline material for a period of about 2 hours to about 48 hours; d) stopping the contact between the titanate support and the alkaline material to provide a support for hydrolysis at a temperature in the range of about 50°C to about 200°C; and e) maintaining the temperature in the range of about 50°C to about 200°C for a period of about 30 minutes to about 6 hours to form a pre-catalyst for hydrolysis. The method may further include contacting a chromium-containing compound with a hydrolyzed precatalyst to form a precatalyst, and calcining the precatalyst to form a catalyst by heating it to a temperature in the range of about 400°C to about 1000°C and maintaining the temperature in the range of about 400°C to about 1000°C for a period of about 1 minute to about 24 hours.

[0006] This article also discloses a method for preparing a catalyst, comprising: a) drying a chromated silica support by heating it to a temperature in the range of about 150°C to about 250°C and maintaining the temperature in the range of about 150°C to about 250°C for a period of about 1 hour to about 24 hours to form a dried chromated silica support; b) contacting the dried chromated silica support with titanium alkoxide (IV) to form a metallized support; c) drying the metallized support by heating it to a temperature in the range of about 50°C to about 200°C and maintaining the temperature in the range of about 50°C to about 200°C for a period of about 30 minutes to about 6 hours to form a dried metallized support; d) contacting the dried metallized support with an alkaline aqueous solution containing about 3 wt% to about 20 wt% of a nitrogen-containing compound. The mixture is subjected to contact for a period of approximately 10 minutes to approximately 6 hours to form a mixture containing a hydrolyzed metallized support, wherein the weight ratio of the amount of alkaline aqueous solution to the amount of alkanolate titanium (IV) in the dried metallized support is approximately 30:1 to approximately 3:1; e) the hydrolyzed metallized support is removed from the mixture containing the hydrolyzed metallized support, and the hydrolyzed metallized support is dried by heating to a temperature in the range of approximately 50°C to approximately 200°C and maintaining the temperature in the range of approximately 50°C to approximately 200°C for a period of approximately 30 minutes to approximately 6 hours to form a precatalyst; and f) the precatalyst is calcined by heating to a temperature in the range of approximately 400°C to approximately 1000°C and maintaining the temperature in the range of approximately 400°C to approximately 1000°C for a period of approximately 1 minute to approximately 24 hours to form a catalyst.

[0007] This article also discloses a method for preparing a catalyst, comprising: a) drying a silica support by heating it to a temperature in the range of about 150°C to about 250°C and maintaining the temperature in the range of about 150°C to about 250°C for a period of about 1 hour to about 24 hours to form a dried support; b) contacting the dried support with titanium alkoxide (IV) to form a titanate support; c) drying the titanate support by heating it to a temperature in the range of about 50°C to about 200°C and maintaining the temperature in the range of about 50°C to about 200°C for a period of about 30 minutes to about 6 hours to form a dried titanate support; d) contacting the dried titanate support with an alkaline aqueous solution containing about 3 wt% to about 20 wt% of a nitrogen-containing compound for a period of about 10 minutes to about 6 hours to form a mixture containing hydrolyzed titanate support, wherein the amount of alkaline aqueous solution is relative to the amount of alkoxide in the dried titanate support. The weight ratio of titanium alkoxide (IV) is from about 30:1 to about 3:1; e) the hydrolyzed titanate support is removed from the mixture containing the hydrolyzed titanate support, and the hydrolyzed titanate support is dried by heating to a temperature in the range of about 50°C to about 200°C and maintaining the temperature in the range of about 50°C to about 200°C for a period of about 30 minutes to about 6 hours to form a hydrolyzed precatalyst; f) a chromium-containing compound is contacted with at least one material selected from the group consisting of: silica support, dried support, titanate support, dried titanate support, mixture containing hydrolyzed titanate support and hydrolyzed precatalyst; and g) the precatalyst is calcined by heating to a temperature in the range of about 400°C to about 1000°C and maintaining the temperature in the range of about 400°C to about 1000°C for a period of about 1 minute to about 24 hours to form a catalyst.

[0008] This article also discloses a method for preparing a catalyst, comprising: a) drying a chromated silica support by heating it to a temperature in the range of about 150°C to about 250°C and maintaining the temperature in the range of about 150°C to about 250°C for a period of about 1 hour to about 24 hours to form a dried chromated silica support; b) contacting the dried chromated silica support with titanium alkoxide (IV) to form a metallized support; c) heating the metallized support to a temperature in the range of about 50°C to about 200°C and maintaining the temperature in the range of about 50°C to about 200°C, while contacting the metallized support with... The process involves: d) contacting the gaseous solution material for approximately 2 hours to approximately 48 hours; d) ceasing contact between the metallization support and the gaseous solution to provide a hydrolyzed metallization support at a temperature ranging from approximately 50°C to approximately 200°C; e) maintaining the temperature of the hydrolyzed metallization support at a temperature ranging from approximately 50°C to approximately 200°C for approximately 30 minutes to approximately 6 hours to form a precatalyst; and f) calcining the precatalyst to form a catalyst by heating it to a temperature ranging from approximately 400°C to approximately 1000°C and maintaining the temperature at a temperature ranging from approximately 400°C to approximately 1000°C for approximately 1 minute to approximately 24 hours.

[0009] This article also discloses a method for preparing a catalyst, comprising: a) drying a silica support by heating it to a temperature in the range of about 150°C to about 250°C and maintaining the temperature in the range of about 150°C to about 250°C for a period of about 1 hour to about 24 hours to form a dried support; b) contacting the dried support with titanium alkoxide (IV) to form a titanate support; c) heating the titanate support to a temperature in the range of about 50°C to about 200°C and maintaining the temperature in the range of about 50°C to about 200°C, while contacting the titanate support with a gas phase solution for a period of about 2 hours to about 48 hours; d) stopping the contact between the titanate support and the gas phase solution. The process involves: e) providing a support for hydrolysis at a temperature ranging from about 50°C to about 200°C; f) maintaining the temperature at a range of about 50°C to about 200°C for a period of about 30 minutes to about 6 hours to form a pre-catalyst for hydrolysis; g) contacting a chromium-containing compound with at least one material selected from the group consisting of: a silica support, a dried support, a titanate support, a hydrolyzed support, and a hydrolyzed pre-catalyst; and g) calcining the pre-catalyst to form a catalyst by heating it to a temperature ranging from about 400°C to about 1000°C and maintaining the temperature at a range of about 400°C to about 1000°C for a period of about 1 minute to about 24 hours. Attached Figure Description

[0010] The following figures form part of this specification and are included to further illustrate certain aspects of this disclosure. A better understanding of the subject matter of this disclosure can be achieved by referring to the figures and the detailed description of the specific aspects presented herein.

[0011] Attached Figure Figure 1 Explain the reaction between the silica support and Ti(OiPr)4. Detailed Implementation

[0012] This disclosure covers olefin polymerization catalysts, methods for preparing olefin polymerization catalysts, and methods for utilizing olefin polymerization catalysts. In one aspect, the method of this disclosure includes contacting a silica support or a chromated silica support (i.e., the support) with titanium to produce a Cr / Si-Ti catalyst. The methods disclosed herein contemplate the application of alkaline treatment (e.g., via contact with a nitrogen-containing compound) during the preparation of the Cr / Si-Ti catalyst to promote the association between titanium and the support. The methods further contemplate that the application of alkaline treatment can reduce emissions of highly reactive volatile organic compounds generated during the production of the Cr / Si-Ti catalyst. While these aspects may be disclosed under specific headings, these headings are not limited to the disclosure found therein. Furthermore, the various aspects and examples disclosed herein can be combined in any manner.

[0013] The methods disclosed herein envision the application of alkaline treatment, for example, via contact with a nitrogen-containing compound. In one aspect, the method for preparing the olefin polymerization catalyst disclosed herein involves using an alkaline aqueous solution containing a nitrogen-containing compound. In a particular aspect, the alkaline aqueous solution comprises water and the nitrogen-containing compound. In some aspects, the alkaline aqueous solution optionally contains a co-solvent.

[0014] The water suitable for alkaline aqueous solutions can be deionized water, distilled water, filtered water, or a combination thereof.

[0015] In one aspect, the alkaline aqueous solution of this disclosure comprises a nitrogen-containing compound. The nitrogen-containing compound can be any nitrogen-containing compound suitable for providing an effective titanate catalyst for olefin polymerization. In another aspect, the nitrogen-containing compound can have structure 1, structure 2, structure 3, structure 4, or a combination thereof.

[0016]

[0017] As described in this article, the nitrogen-containing compounds utilized contain R 1 R 2 R 3 R 4 R 5 x, y, and z are independent elements of the nitrogen-containing compound structures in which they reside, and are described independently in this paper. The R... 1 R 2 R 3 R4 R 5 Independent descriptions of x, y, and / or z can be used without limitation and in any combination for additional descriptions containing R. 1 R 2 R 3 R 4 R 5 Any nitrogen-containing compound structure of x, y and / or z

[0018] Typically, having R 1 R 2 R 3 R 4 and / or R 5 The corresponding nitrogen-containing compounds R 1 R 2 R 3 R 4 and / or R 5 Each can be independently a hydrogen group, an organic group, a hydrocarbon group, or an aryl group. On one hand, R... 1 R 2 R 3 R 4 and / or R 5 Each can be independently defined as C1 to C 30 Organic groups; alternatively, C1 to C 12 Organic groups; or alternatively, C1 to C6 organic groups. In another aspect, R 1 R 2 R 3 R 4 and / or R 5 Each can be independently defined as C1 to C 30 Hydrocarbon group; alternatively, C1 to C 12 Hydrocarbon group; or alternatively, C1 to C6 hydrocarbon group. In other respects, R 1 R 2 R 3 R 4 and / or R 5 Each can be independently classified as C6 to C 30 Aryl; or alternatively, C6 to C 12 Aryl. In another aspect, R can be used as an ingredient in the nitrogen-containing compounds of this disclosure. 1 R 2 R 3 R 4 and / or R 5Any organic group, hydrocarbon group, or aryl group may be substituted or unsubstituted. Those skilled in the art will understand that the terms “alkyl,” “hydrocarbon group,” “organic group,” and “aryl group” are used herein according to their definitions from the IUPAC Compendium of Chemical Terminology, 2nd edition (1997).

[0019] In certain aspects, it can be used as R 1 R 2 R 3 R 4 and / or R 5 Any substituted organic group, substituted hydrocarbon group, or substituted aryl group may contain one or more non-hydrogen substituents. The non-hydrogen substituents applicable herein may be halogens, C1 to C2, or C4. 12 Hydrocarbon group, C1 to C 12 Hydroxyl groups or combinations thereof. In one aspect, the halogen used as a non-hydrogen substituent can be fluorine, chlorine, bromine, or iodine. The C1 to C1 groups applicable herein... 12 Non-limiting examples of hydrocarbon oxy groups include methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy, phenoxy, tolyloxy, xyloxy, trimethylphenoxy, and benzoyloxy.

[0020] On another front, the nitrogen-containing compound of this disclosure having structure 1 comprises three R... 1 Groups, of which three R 1 Each of the groups can have an independent value. On one hand, nitrogen-containing compounds with structure 2 contain four R groups. 2 Groups, of which four R 2 Each of the groups can have an independent value. In another aspect, nitrogen-containing compounds with structure 3 contain two R groups. 3 Groups, in which two R groups 3 Each of the groups can have an independent value. In another aspect, nitrogen-containing compounds with structure 4 contain two R groups. 4 Groups, in which two R groups 4 Each of the groups can have an independent value.

[0021] In one aspect, the nitrogen-containing compounds applicable to this disclosure may be amides, amidines, amines, diamines, triamines, amino acids, ammonium hydroxide, formamides, hydrazine, hydroxylamine, imidazoles, piperazines, piperidines, pyrazines, pyrazoles, pyridines, pyrimidines, pyrroles, ureas, or combinations thereof. In another aspect, the amides, amidines, amines, diamines, triamines, amino acids, ammonium hydroxide, formamides, hydrazines, hydroxylamines, imidazoles, piperazines, piperidines, pyrazines, pyrazoles, pyrimidines, pyrroles, and / or ureas used as nitrogen-containing compounds may contain one or more substituents. In another aspect, any substituent contained in any nitrogen-containing compound of this disclosure may be halogens, C1 to C2 compounds, or C4 compounds. 12 Organic groups, C1 to C 12 Hydrocarbon group, C1 to C 12 Hydroxyl groups or combinations thereof. Halogens used as substituents in any aspect disclosed herein may be fluorine, chlorine, bromine, or iodine. Suitable substituents are C1 to C2. 12 Non-limiting examples of hydrocarbon oxy groups include methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy, phenoxy, tolyloxy, xyloxy, trimethylphenoxy, and benzoyloxy.

[0022] In other aspects, non-limiting examples of specific nitrogen-containing compounds applicable to this disclosure include ammonia, ammonium hydroxide, tetraethylammonium hydroxide, tetramethylammonium hydroxide, hydrazine, hydroxylamine, trimethylamine, triethylamine, acetamide, creatine, 1,4-diazabicyclo[2.2.2]octane (DABCO), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), N,N- Diisopropylethylamine (DIPEA), dimethyl carbamate, formamide, methylformamide, dimethylformamide, dimethylglycine, 1,4-dimethylpiperazine (DMP), 1,3-dimethylurea, imidazole, piperazine, piperidine, pyrazine, pyrazole, pyridine, pyrimidine, pyrrole, tetramethylethylenediamine (TMEDA), triazine, 1,3,5-triazacyclohexane, 1,3,5-trimethyl-1,3,5-triazacyclohexane (TMTAC), or combinations thereof.

[0023] In another aspect, the alkaline aqueous solution of this disclosure may optionally contain a co-solvent. In one aspect, the co-solvent suitable for use herein may be an organic solvent, such as an alcohol, ester, ketone, or a combination thereof. Non-limiting examples of alcohols suitable as co-solvents include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, or combinations thereof. Non-limiting examples of esters suitable as co-solvents include ethyl acetate, propyl acetate, butyl acetate, isobutyl isobutyrate, methyl lactate, ethyl lactate, or combinations thereof. Non-limiting examples of ketones suitable as co-solvents include acetone, ethyl methyl ketone, methyl isobutyl ketone, or combinations thereof.

[0024] In one aspect, the amount of nitrogen-containing compounds present in the alkaline aqueous solution may range from about 1 wt% to about 50 wt% based on the total weight of the alkaline aqueous solution; alternatively, from about 3 wt% to about 20 wt%; or alternatively, from about 4 wt% to about 10 wt%. In the aspect where the alkaline aqueous solution contains a co-solvent, the volume ratio of the co-solvent to water may range from about 1:20 to about 20:1; alternatively, from about 1:10 to about 10:1; alternatively, from about 1:5 to about 5:1; or alternatively, from about 1:2 to about 2:1. The remainder of the alkaline aqueous solution comprises water as disclosed herein.

[0025] In another aspect, the method for preparing the olefin polymerization catalyst disclosed herein envisions the use of an alkaline treatment, for example, via a gas-phase mixture comprising a nitrogen-containing compound. In one aspect, the gas-phase mixture comprises vapors associated with the alkaline liquid (e.g., vapors in equilibrium with the alkaline liquid). In a particular aspect, the alkaline liquid comprises an aqueous solution of the nitrogen-containing compound disclosed herein. In another aspect, the alkaline liquid comprises an alcohol, non-limiting examples of which include methanol, ethanol, n-propanol, isopropanol, or combinations thereof.

[0026] In one aspect, the amount of nitrogen-containing compounds in the aqueous solution is from about 3 wt% to about 20 wt% based on the total weight of the aqueous solution. In another aspect, the alkaline liquid is contained in the volume ratio of the aqueous solution to the alcohol in the range of about 10:1 to about 1:10; alternatively, about 4:1 to about 1:4; alternatively, about 7:3 to about 3:7; or alternatively, about 1.2:1 to about 1:1.2.

[0027] In certain respects, the alkaline liquid and the vapor associated with the alkaline liquid may each independently have a temperature in the range of about 120°C to about 200°C; or alternatively, about 150°C to about 170°C.

[0028] In another aspect, the gas-phase mixture applicable herein includes vapors associated with an alkaline liquid comprising an aqueous solution of MeOH and NH4OH. In another aspect, the gas-phase mixture includes ammonia, methanol, water, or a combination thereof. In one aspect, the amount of NH4OH present in the aqueous solution may be in the range of about 2 wt% to about 10 wt% based on the total weight of the aqueous solution. In another aspect, the alkaline liquid comprises a volume ratio of MeOH to the aqueous solution in the range of about 7:3 to about 3:7, from about 10:1 to about 1:10. In another aspect, the alkaline liquid and the vapor associated with the alkaline liquid may each independently have a temperature in the range of about 150°C to about 170°C.

[0029] In a particular aspect, the olefin polymerization catalyst of this disclosure comprises titanium. The titanium may be sourced from any titanium-containing compound capable of providing effective titanation to the olefin polymerization catalyst. In another aspect, the titanium-containing compound comprises a tetravalent titanium (Ti(IV)) compound or a trivalent titanium (Ti(III)) compound. The Ti(IV) compound may be any compound containing Ti(IV); alternatively, the Ti(IV) compound may be any compound capable of releasing Ti(IV) species upon dissolution in solution. The Ti(III) compound may be any compound containing Ti(III); alternatively, the Ti(III) compound may be any compound capable of releasing Ti(III) species upon dissolution in solution.

[0030] In one aspect, the titanium-containing compounds applicable to this disclosure comprise Ti(IV) compounds having at least one alkoxy group; or alternatively, at least two alkoxy groups. The Ti(IV) compounds applicable to this disclosure include, but are not limited to, those with the general formula TiO(OR). 6 2. Ti(OR) 6 )2(acac)2、Ti(OR 6 )2(oxal), and its combination of Ti(IV) compounds, wherein R 6 It may be ethyl, isopropyl, n-propyl, isobutyl, n-butyl, or a combination thereof; "acac" means acetylpyruvate; and "oxalic acid" means oxalate. Alternatively, the titanium-containing compound includes titanium alkoxide (IV). In one aspect, titanium alkoxide (IV) may be titanium ethoxide (IV), titanium isopropoxide (IV), titanium n-propoxide (IV), titanium n-butoxide (IV), titanium 2-ethylhexanoate (IV), or a combination thereof. In a particular aspect, the titanium-containing compound may be titanium isopropoxide (IV).

[0031] In another aspect, titanium-containing compounds applicable to this disclosure may comprise titanium halide (IV), with non-limiting examples including titanium chloride (IV) and titanium bromide (IV).

[0032] The amount of titanium present in the olefin polymerization catalyst may range from about 0.01 wt% to about 10 wt% based on the total weight of the olefin polymerization catalyst; alternatively, from about 0.5 wt% to about 5 wt%; alternatively, from about 1 wt% to about 4 wt%; or alternatively, from about 2 wt% to about 4 wt% of titanium. On the other hand, the amount of titanium present in the olefin polymerization catalyst may range from about 1 wt% to about 5 wt% based on the total weight of the olefin polymerization catalyst. In this document, the titanium percentage refers to the weight percentage (wt%) of titanium associated with the olefin polymerization catalyst based on the total weight of the olefin polymerization catalyst after all processing steps have been completed (i.e., after activation via calcination).

[0033] In another aspect, the weight ratio of the amount of alkaline aqueous solution to the amount of titanium-containing compound used to prepare the olefin polymerization catalyst disclosed herein may be in the range of about 100:1 to about 1:1; or alternatively, from 30:1 to about 3:1. Alternatively, the amount of alkaline aqueous solution used may be sufficient to provide an equivalent molar ratio of nitrogen-containing compound to titanium-containing compound in the range of about 100:1 to about 1:2; alternatively, from about 50:1 to about 1:1; or alternatively, from about 20:1 to about 3:1.

[0034] In another aspect, the olefin polymerization catalyst of this disclosure comprises a silica support. The silica support may be any silica support suitable for preparing the olefin polymerization catalyst disclosed herein. The silica support may have a surface area and pore volume that effectively provide for generating an active olefin polymerization catalyst. In one aspect of this disclosure, the silica support has a pore size of approximately 100 m². 2 / gram to approximately 1000 meters 2 / gram; alternatively, approximately 250 meters 2 / gram to approximately 1000 meters 2 / gram; alternatively, approximately 250 meters 2 / gram to approximately 700 meters 2 / gram; alternatively, approximately 250 meters 2 / gram to approximately 600 meters 2 Within the range of / gram; or alternatively, greater than approximately 250 meters. 2 / gram of surface area. A further characteristic of silica carriers is that they are greater than approximately 0.9 cm². 3 / gram; alternatively, greater than about 1.0 cm. 3 / gram; or alternatively, greater than about 1.5 centimeters. 3 / gram pore volume. In one aspect of this disclosure, the silica support is characterized by a pore volume of approximately 1.0 cm². 3 / gram to approximately 2.5 cm 3 The silica support is characterized by an average particle size ranging from about 10 micrometers to about 500 micrometers; alternatively, from about 25 micrometers to about 300 micrometers; or alternatively, from about 40 micrometers to about 150 micrometers. Typically, the average pore size of the silica support ranges from about 10 angstroms to about 1000 angstroms. In one aspect of this disclosure, the average pore size of the silica support ranges from about 50 angstroms to about 500 angstroms; or alternatively, from about 75 angstroms to about 350 angstroms.

[0035] The silica support suitable for this disclosure may contain more than about 50 wt% silica by weight of the total silica support; alternatively, more than about 80 wt% silica; or alternatively, more than about 95 wt% silica. The silica support may be prepared using any suitable method, for example, by hydrolyzing tetrachlorosilane (SiCl4) with water or by contacting sodium silicate with an inorganic acid. The silica support may include additional components that do not adversely affect the catalyst, such as zirconium oxide, alumina, thorium oxide, magnesium oxide, fluorides, sulfates, phosphates, or combinations thereof. Non-limiting examples of silica supports suitable for this disclosure include ES70, which has a 300-meter diameter... 2 / gram of surface area and 1.6 cm 3 / gram pore volume of commercially available silica carrier material from PQ Corporation; and V398400, which is commercially available silica carrier material from Evonik.

[0036] In a particular aspect of this disclosure, the silica support applicable to this disclosure comprises chromium. A silica support comprising chromium may be referred to as a chromated silica support. In another aspect, a chromated silica support comprises the features of the silica supports disclosed herein, while additionally containing chromium. A non-limiting example of a chromated silica support is HW30A, a chromated silica support material commercially available from WRGrace and Company.

[0037] The silica support may be present in the olefin polymerization catalyst in an amount ranging from about 50 wt% to about 99 wt%; or alternatively, from about 80 wt% to about 99 wt%. In this document, the silica support percentage refers to the weight percentage (wt%) of the silica support associated with the olefin polymerization catalyst, based on the total weight of the olefin polymerization catalyst, after all processing steps have been completed (i.e., after activation via calcination).

[0038] In another aspect, the olefin polymerization catalyst of this disclosure comprises chromium. The source of chromium may be any chromium-containing compound capable of providing a sufficient amount of chromium to the olefin polymerization catalyst. In one aspect, the chromium-containing compound may be a water-soluble or hydrocarbon-soluble chromium compound. Examples of water-soluble chromium compounds include chromium trioxide, chromium acetate, chromium nitrate, or combinations thereof. Examples of hydrocarbon-soluble chromium compounds include tert-butyl chromate, dicyclopentadienylchromium(II), chromium acetylatedpyruvate(III), or combinations thereof. In one aspect of this disclosure, the chromium-containing compound may be a chromium(II) compound, a chromium(III) compound, or a combination thereof. Suitable chromium(III) compounds include, but are not limited to, chromium carboxylate(III), chromium naphthenate(III), chromium halide(III), chromium sulfate(III), chromium nitrate(III), chromium diacid(III), or combinations thereof. Specific chromium(III) compounds include, but are not limited to, chromium sulfate(III), chromium chloride(III), chromium nitrate(III), chromium bromide(III), chromium acetylatedpyruvate(III), and chromium acetate(III). Suitable chromium(II) compounds include, but are not limited to, chromium(II) chloride, chromium(II) bromide, chromium(II) iodide, chromium(II) sulfate, chromium(II) acetate, or combinations thereof.

[0039] The amount of chromium present in the olefin polymerization catalyst may range from about 0.01 wt% to about 10 wt% based on the total weight of the olefin polymerization catalyst; alternatively, from about 0.5 wt% to about 5 wt%; alternatively, from about 1 wt% to about 4 wt%; or alternatively, from about 2 wt% to about 4 wt% of chromium. On the other hand, the amount of chromium present in the olefin polymerization catalyst may range from about 1 wt% to about 5 wt% based on the total weight of the olefin polymerization catalyst. In this document, chromium percentage refers to the weight percentage (wt%) of chromium associated with the olefin polymerization catalyst based on the total weight of the olefin polymerization catalyst after all processing steps have been completed (i.e., after activation via calcination).

[0040] In another aspect, one or more components of the olefin polymerization catalyst of this disclosure can be contacted in the presence of a solvent. In a particular aspect, suitable solvents may be hydrocarbons, alcohols, organic solvents, aqueous solvents, or combinations thereof. In one aspect, hydrocarbons suitable as solvents may be aliphatic hydrocarbons, halogenated aliphatic hydrocarbons, aromatic hydrocarbons, halogenated aromatic hydrocarbons, or combinations thereof. Non-limiting examples of hydrocarbons suitable as solvents include benzene, chloroform, carbon tetrachloride, chlorobenzene, dichlorobenzene, dichloroethane, ethylbenzene, hexane, heptane, dichloromethane, octane, trichloroethane, toluene, xylene, or combinations thereof. In another aspect, hydrocarbon solvents suitable for this disclosure include heptane. Non-limiting examples of alcohols suitable as solvents include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, pentanol, hexanol, cyclohexanol, heptanol, octanol, benzyl alcohol, phenol, or combinations thereof. In another aspect, suitable organic solvents for this disclosure may be esters, ketones, or combinations thereof. Non-limiting examples of esters suitable as solvents include ethyl acetate, propyl acetate, butyl acetate, isobutyl isobutyrate, methyl lactate, ethyl lactate, or combinations thereof. Non-limiting examples of ketones suitable as solvents include acetone, ethyl methyl ketone, methyl isobutyl ketone, or combinations thereof.

[0041] In one aspect of this disclosure, the catalyst components disclosed herein can be contacted by means of this disclosure in any order or manner that a person skilled in the art would deem suitable to produce an olefin polymerization catalyst having the features disclosed herein.

[0042] In one aspect, a method for preparing an olefin polymerization catalyst includes drying a silica support to form a dry support before contact with any other components of the olefin polymerization catalyst. The silica support can be dried by heating to a temperature ranging from about 110°C to about 500°C; alternatively, from about 150°C to about 300°C; or alternatively, from about 150°C to about 250°C. The method further includes maintaining the temperature of the silica support at a time period of about 110°C to about 500°C; alternatively, from about 150°C to about 300°C; or alternatively, from about 150°C to about 250°C for about 1 hour to about 24 hours; alternatively, from about 5 hours to about 24 hours; or alternatively, from about 5 hours to about 12 hours to form a dry support. The drying of the silica support can be carried out in an inert atmosphere (e.g., under vacuum, He, Ar, or N2 gas). The degree of dryness of the dried support can be measured as the weight loss after drying at a temperature of about 250°C for a time period of about 1 hour to about 12 hours. On the one hand, the weight loss of the dried carrier after drying is less than about 3 wt%; alternatively, less than about 2 wt%; or alternatively, less than about 1 wt%.

[0043] The method may further include contacting the dried support with a titanium-containing compound of the type disclosed herein to form a titanate support. The titanate support may be dried by heating to a temperature in the range of about 50°C to about 500°C; alternatively, about 50°C to about 200°C; or alternatively, about 80°C to about 150°C. The method further includes maintaining the temperature of the titanate support at a time period of about 50°C to about 500°C; alternatively, about 50°C to about 200°C; or alternatively, about 80°C to about 150°C for about 30 minutes to about 24 hours; alternatively, about 30 minutes to about 6 hours; or alternatively, about 2 hours to about 6 hours to form a dried titanate support. The method may further include contacting the dried titanate support with an alkaline aqueous solution of the type disclosed herein to form a mixture comprising hydrolyzed titanate support. In another aspect, the dried titanate support may be contacted with an alkaline aqueous solution for about 1 minute to about 24 hours; alternatively, for about 10 minutes to about 6 hours; or alternatively, for a period of about 1 hour to about 3 hours. In one aspect, the mixture formed by contacting the dried titanate support with an alkaline aqueous solution may be a slurry, suspension, colloid, or a combination thereof. The method further includes removing the hydrolyzed titanate support from the mixture containing the hydrolyzed titanate support. In one aspect, the hydrolyzed titanate support may be removed by any suitable method, non-limiting examples of which include filtration, centrifugation, gravimetric sedimentation, membrane filtration, or a combination thereof. The method may further include drying the hydrolyzed titanate support by heating to a temperature in the range of about 35°C to about 500°C; alternatively, about 50°C to about 200°C; or alternatively, about 75°C to about 125°C. The method further includes maintaining the temperature of the hydrolyzed titanate support at a range of about 35°C to about 500°C; alternatively, about 50°C to about 200°C; or alternatively, about 75°C to about 125°C for about 5 minutes to about 24 hours; alternatively, about 30 minutes to about 12 hours; alternatively, about 30 minutes to about 6 hours; or alternatively, about 1 hour to about 3 hours for a period of time to form the hydrolyzed precatalyst.

[0044] In another aspect, a method for preparing an olefin polymerization catalyst includes preparing a dried chromated silica support. The method may include contacting a chromium-containing compound with a silica support (both of which are of the type disclosed herein) to form a chromated silica support, which is then dried by heating to a temperature in the range of about 110°C to about 500°C; alternatively, about 150°C to about 300°C; or alternatively, about 150°C to about 250°C. The method may further include maintaining the temperature of the chromated silica support at a time period of about 30 minutes to about 24 hours; alternatively, about 30 minutes to about 6 hours; or alternatively, about 2 hours to about 6 hours to form the dried chromated silica support. Alternatively, the chromium-containing compound may be contacted with the dried support to form the dried chromated silica support. In another alternative, the chromated silica support (e.g., HA30W) disclosed herein is dried by heating to a temperature ranging from about 110°C to about 500°C; alternatively, from about 150°C to about 300°C; or alternatively, from about 150°C to about 250°C and maintaining the temperature of the chromated silica support at a time period of about 110°C to about 500°C; alternatively, from about 150°C to about 300°C; or alternatively, from about 150°C to about 250°C for about 30 minutes to about 24 hours; alternatively, from about 30 minutes to about 6 hours; or alternatively, from about 2 hours to about 6 hours to form a dried chromated silica support. The drying of the chromated silica support can be carried out in an inert atmosphere (e.g., under vacuum, He, Ar, or N2 gas). The degree of dryness of the dried chromated silica support can be measured as the weight loss after drying at a temperature of about 250°C for a time period of about 1 hour to about 12 hours. On the one hand, the weight loss after drying of the dried chromated silica support is less than about 3 wt%; alternatively, less than about 2 wt%; or alternatively, less than about 1 wt%.

[0045] The method further includes contacting a dried chromated silica support with a titanium-containing compound of the type disclosed herein to form a metallized support, which is then dried by heating to a temperature in the range of about 50°C to about 500°C; alternatively, about 50°C to about 200°C; or alternatively, about 80°C to about 150°C. The method further includes maintaining the temperature of the metallized support at a time period of about 50°C to about 500°C; alternatively, about 50°C to about 200°C; or alternatively, about 80°C to about 150°C for about 30 minutes to about 24 hours; alternatively, about 30 minutes to about 6 hours; or alternatively, about 2 hours to about 6 hours to form a dried metallized support. In one aspect, the method may further include contacting the dried metallized support with an alkaline aqueous solution of the type disclosed herein to form a mixture comprising a hydrolyzed metallized support. In one aspect, the dried metallized support may be contacted with an alkaline aqueous solution for a period of approximately 1 minute to approximately 24 hours, and the resulting mixture may be a slurry, suspension, colloid, or a combination thereof. The method further includes removing the hydrolyzed metallized support from the mixture containing the hydrolyzed metallized support by any suitable method, non-limiting examples of which include filtration, centrifugation, gravimetric sedimentation, membrane filtration, or a combination thereof. The method may further include drying the hydrolyzed metallized support to form a precatalyst by heating it to a temperature in the range of about 35°C to about 500°C; alternatively, about 50°C to about 200°C; or alternatively, about 75°C to about 125°C and maintaining the temperature of the hydrolyzed metallized support in the range of about 35°C to about 500°C; alternatively, about 50°C to about 200°C; or alternatively, about 75°C to about 125°C for about 5 minutes to about 24 hours; alternatively, about 30 minutes to about 12 hours; alternatively, about 30 minutes to about 6 hours; or alternatively, about 1 hour to about 3 hours.

[0046] In an alternative approach, methods for preparing olefin polymerization catalysts involve contacting a chromium-containing compound with a titanate support to form a metallized support, which is subsequently dried to form a dried metallized support. The dried metallized support may be contacted with an alkaline aqueous solution to form a mixture containing hydrolyzed metallized support. The hydrolyzed metallized support may be removed from the mixture containing the hydrolyzed metallized support and dried to form a pre-catalyst.

[0047] In another alternative, a chromium-containing compound is contacted with a dried titanate support to form a dried metallized support, which is then contacted with an alkaline aqueous solution to form a mixture containing a hydrolyzed metallized support. The hydrolyzed metallized support can be removed from the mixture containing the hydrolyzed metallized support and dried to form a pre-catalyst.

[0048] In another alternative, a chromium-containing compound is contacted with a mixture comprising a hydrolyzed titanate support prepared in an alkaline aqueous solution to form a mixture comprising a hydrolyzed metallized support. The hydrolyzed metallized support can be removed from the mixture comprising the hydrolyzed metallized support and dried to form a pre-catalyst.

[0049] In another alternative, a chromium-containing compound is contacted with a hydrolyzed precatalyst prepared using an alkaline aqueous solution to form a precatalyst.

[0050] In a particular aspect, a method for preparing an olefin polymerization catalyst includes drying a silica support to form a dry support prior to contact with any other components of the olefin polymerization catalyst. The silica support can be dried by heating to a temperature ranging from about 110°C to about 500°C; alternatively, from about 150°C to about 300°C; or alternatively, from about 150°C to about 250°C. The method further includes maintaining the temperature of the silica support at a time period of about 110°C to about 500°C; alternatively, from about 150°C to about 300°C; or alternatively, from about 150°C to about 250°C for about 1 hour to about 24 hours; alternatively, from about 5 hours to about 24 hours; or alternatively, from about 5 hours to about 12 hours to form a dry support. The drying of the silica support can be carried out in an inert atmosphere (e.g., under vacuum, He, Ar, or N2 gas). The degree of dryness of the dried support can be measured as the weight loss after drying at a temperature of about 250°C for a time period of about 1 hour to about 12 hours. On the one hand, the weight loss of the dried carrier after drying is less than about 3 wt%; alternatively, less than about 2 wt%; or alternatively, less than about 1 wt%.

[0051] The method further includes contacting a dried support with a titanium-containing compound of the type disclosed herein to form a mixture containing a titanate support. In one aspect, the mixture containing the titanate support contains a solvent suitable for use as disclosed herein (e.g., heptane). The method may further include heating the mixture containing the titanate support to a temperature in the range of about 35°C to about 500°C; alternatively, about 50°C to about 200°C; or alternatively, about 75°C to about 125°C and maintaining the temperature in the range of about 35°C to about 500°C; alternatively, about 50°C to about 200°C; or alternatively, about 75°C to about 125°C. During heating, the mixture containing the titanate support may be contacted with a gas phase mixture for a period of about 30 minutes to about 48 hours; alternatively, about 1 hour to about 24 hours; or alternatively, about 2 hours to about 8 hours. In one aspect, contacting the mixture containing the titanate support with the gas phase mixture includes maintaining the gas phase mixture flowing through the mixture containing the titanate support. In a non-limiting example, the stream of the gas phase mixture may be bubbled through the mixture containing the titanate support. The method further includes stopping contact between the mixture containing the titanate support and the gas phase mixture to provide a mixture containing the hydrolyzed support at a temperature ranging from about 35°C to about 500°C; alternatively, from about 50°C to about 200°C; or alternatively, from about 75°C to about 125°C. The method further includes drying the hydrolyzed support to form a hydrolyzed pre-catalyst by maintaining the temperature of the hydrolyzed support at a temperature ranging from about 35°C to about 500°C; alternatively, from about 50°C to about 200°C; or alternatively, from about 75°C to about 125°C.

[0052] In another aspect, a method for preparing an olefin polymerization catalyst includes preparing a dried chromated silica support. The method may include contacting a chromium-containing compound with a silica support (both of which are of the type disclosed herein) to form a chromated silica support, which is then dried by heating to a temperature in the range of about 110°C to about 500°C; alternatively, about 150°C to about 300°C; or alternatively, about 150°C to about 250°C. The method may further include maintaining the temperature of the chromated silica support at a time period of about 30 minutes to about 24 hours; alternatively, about 30 minutes to about 6 hours; or alternatively, about 2 hours to about 6 hours to form the dried chromated silica support. Alternatively, the chromium-containing compound may be contacted with the dried support to form the dried chromated silica support. In another alternative, the chromated silica support (e.g., HA30W) disclosed herein is dried by heating to a temperature ranging from about 110°C to about 500°C; alternatively, from about 150°C to about 300°C; or alternatively, from about 150°C to about 250°C and maintaining the temperature of the chromated silica support at a time period of about 110°C to about 500°C; alternatively, from about 150°C to about 300°C; or alternatively, from about 150°C to about 250°C for about 30 minutes to about 24 hours; alternatively, from about 30 minutes to about 6 hours; or alternatively, from about 2 hours to about 6 hours to form a dried chromated silica support. The drying of the chromated silica support can be carried out in an inert atmosphere (e.g., under vacuum, He, Ar, or N2 gas). The degree of dryness of the dried chromated silica support can be measured as the weight loss after drying at a temperature of about 250°C for a time period of about 1 hour to about 12 hours. On the one hand, the weight loss after drying of the dried chromated silica support is less than about 3 wt%; alternatively, less than about 2 wt%; or alternatively, less than about 1 wt%.

[0053] The method further includes contacting a dried chromated silica support with a titanium-containing compound of the type disclosed herein to form a mixture containing a metallized support. In another aspect, the mixture containing the metallized support contains a solvent suitable for use as disclosed herein (e.g., heptane). The method may further include heating the mixture containing the metallized support to a temperature in the range of about 35°C to about 500°C; alternatively, about 50°C to about 200°C; or alternatively, about 75°C to about 125°C and maintaining the temperature in the range of about 35°C to about 500°C; alternatively, about 50°C to about 200°C; or alternatively, about 75°C to about 125°C. During heating, the mixture containing the metallized support may be contacted with a gaseous mixture for about 30 minutes to about 48 hours; alternatively, about 1 hour to about 24 hours; or alternatively, about 2 hours to about 8 hours. In another aspect, contacting the mixture containing the metallized support with the gaseous mixture includes maintaining the gaseous mixture flowing through the mixture containing the metallized support. In a non-limiting example, the stream of the gas phase mixture may be bubbled through the mixture containing the metallized support. The method further includes stopping contact between the mixture containing the metallized support and the gas phase mixture to provide a mixture containing the hydrolyzed metallized support at a temperature ranging from about 35°C to about 500°C; alternatively, from about 50°C to about 200°C; or alternatively, from about 75°C to about 125°C. The method further includes drying the hydrolyzed metallized support to form a pre-catalyst by maintaining the temperature of the hydrolyzed metallized support at a temperature ranging from about 35°C to about 500°C; alternatively, from about 50°C to about 200°C; or alternatively, from about 75°C to about 125°C.

[0054] Alternatively, methods for preparing olefin polymerization catalysts involve contacting a chromium-containing compound with a mixture containing a titanate support to form a mixture containing a metallized support. In one aspect, the mixture containing the titanate support contains a solvent suitable for use as disclosed herein (e.g., heptane). The mixture containing the metallized support may be heated and contacted with a gas-phase mixture to provide a mixture containing a hydrolyzed metallized support. The hydrolyzed metallized support may be dried to form a pre-catalyst.

[0055] In another alternative, the chromium-containing compound is contacted with a mixture comprising a hydrolyzed support prepared by a gas-phase mixture to form a mixture comprising a hydrolyzed metallized support. In one aspect, the hydrolyzed metallized support can be dried to form a pre-catalyst.

[0056] In another alternative, chromium-containing compounds are contacted with a hydrolyzed precatalyst prepared using a gas-phase mixture to form a precatalyst.

[0057] In a particular aspect, a method for preparing an olefin polymerization catalyst includes drying a silica support to form a dry support prior to contact with any other components of the olefin polymerization catalyst. The silica support can be dried by heating to a temperature ranging from about 110°C to about 500°C; alternatively, from about 150°C to about 300°C; or alternatively, from about 150°C to about 250°C. The method further includes maintaining the temperature of the silica support at a time period of about 110°C to about 500°C; alternatively, from about 150°C to about 300°C; or alternatively, from about 150°C to about 250°C for about 1 hour to about 24 hours; alternatively, from about 5 hours to about 24 hours; or alternatively, from about 5 hours to about 12 hours to form a dry support. The drying of the silica support can be carried out in an inert atmosphere (e.g., under vacuum, He, Ar, or N2 gas). The degree of dryness of the dried support can be measured as the weight loss after drying at a temperature of about 250°C for a time period of about 1 hour to about 12 hours. On the one hand, the weight loss of the dried carrier after drying is less than about 3 wt%; alternatively, less than about 2 wt%; or alternatively, less than about 1 wt%.

[0058] The method further comprises contacting a dried support with a titanium-containing compound of the type disclosed herein to form a mixture comprising a titanate support. In another aspect, the mixture comprising a titanate support comprises a solvent suitable for use as disclosed herein (e.g., heptane). The method may further comprise heating the mixture comprising a titanate support to a temperature in the range of about 35°C to about 500°C; alternatively, about 50°C to about 200°C; or alternatively, about 75°C to about 125°C and maintaining the temperature in the range of about 35°C to about 500°C; alternatively, about 50°C to about 200°C; or alternatively, about 75°C to about 125°C. During heating, the mixture comprising a titanate support may be contacted with an alkaline aqueous solution for about 30 minutes to about 48 hours; alternatively, about 1 hour to about 24 hours; or alternatively, for a period of about 2 hours to about 8 hours. In one aspect, the alkaline aqueous solution and the mixture comprising a titanate support are insoluble and do not mix upon contact, wherein the contact comprises liquid / liquid extraction and optional agitation. The method further includes stopping contact between the mixture containing the titanate support and the alkaline aqueous solution (e.g., separating the mixture and the solution) to provide a mixture containing the hydrolyzed support at a temperature ranging from about 35°C to about 500°C; alternatively, from about 50°C to about 200°C; or alternatively, from about 75°C to about 125°C. The method further includes drying the hydrolyzed support to form a hydrolyzed pre-catalyst by maintaining the temperature of the hydrolyzed support at a temperature ranging from about 35°C to about 500°C; alternatively, from about 50°C to about 200°C; or alternatively, from about 75°C to about 125°C.

[0059] In one aspect, a method for preparing an olefin polymerization catalyst includes preparing a dried chromated silica support. The method may include contacting a chromium-containing compound with a silica support (both of which are of the type disclosed herein) to form a chromated silica support, which is then dried by heating to a temperature in the range of about 110°C to about 500°C; alternatively, about 150°C to about 300°C; or alternatively, about 150°C to about 250°C. The method may further include maintaining the temperature of the chromated silica support at a time period of about 30 minutes to about 24 hours; alternatively, about 30 minutes to about 6 hours; or alternatively, about 2 hours to about 6 hours to form a dried chromated silica support. Alternatively, the chromium-containing compound may be contacted with the dried support to form the dried chromated silica support. In another alternative, the chromated silica support (e.g., HA30W) disclosed herein is dried by heating to a temperature ranging from about 110°C to about 500°C; alternatively, from about 150°C to about 300°C; or alternatively, from about 150°C to about 250°C and maintaining the temperature of the chromated silica support at a time period of about 110°C to about 500°C; alternatively, from about 150°C to about 300°C; or alternatively, from about 150°C to about 250°C for about 30 minutes to about 24 hours; alternatively, from about 30 minutes to about 6 hours; or alternatively, from about 2 hours to about 6 hours to form a dried chromated silica support. The drying of the chromated silica support can be carried out in an inert atmosphere (e.g., under vacuum, He, Ar, or N2 gas). The degree of dryness of the dried chromated silica support can be measured as the weight loss after drying at a temperature of about 250°C for a time period of about 1 hour to about 12 hours. On the one hand, the weight loss after drying of the dried chromated silica support is less than about 3 wt%; alternatively, less than about 2 wt%; or alternatively, less than about 1 wt%.

[0060] The method further comprises contacting a dried chromated silica support with a titanium-containing compound of the type disclosed herein to form a mixture comprising a metallized support. In another aspect, the mixture comprising a metallized support comprises a solvent suitable for use as disclosed herein (e.g., heptane). The method may further comprise heating the mixture comprising a metallized support to a temperature in the range of about 35°C to about 500°C; alternatively, about 50°C to about 200°C; or alternatively, about 75°C to about 125°C and maintaining the temperature in the range of about 35°C to about 500°C; alternatively, about 50°C to about 200°C; or alternatively, about 75°C to about 125°C. During heating, the mixture comprising a metallized support may be contacted with an alkaline aqueous solution for about 30 minutes to about 48 hours; alternatively, about 1 hour to about 24 hours; or alternatively, for a period of about 2 hours to about 8 hours. In one aspect, the alkaline aqueous solution and the mixture comprising the titanate support are insoluble and do not mix upon contact, wherein the contact comprises liquid / liquid extraction and optional agitation. The method further includes stopping contact between the mixture containing the titanate support and the alkaline aqueous solution (e.g., separating the mixture and the solution) to provide a hydrolyzed mixture containing the metallized support at a temperature ranging from about 35°C to about 500°C; alternatively, from about 50°C to about 200°C; or alternatively, from about 75°C to about 125°C. The method further includes drying the hydrolyzed metallized support to form a pre-catalyst by maintaining the temperature of the hydrolyzed metallized support at a temperature ranging from about 35°C to about 500°C; alternatively, from about 50°C to about 200°C; or alternatively, from about 75°C to about 125°C.

[0061] Alternatively, methods for preparing olefin polymerization catalysts involve contacting a chromium-containing compound with a mixture containing a titanate support to form a mixture containing a metallized support. In one aspect, the mixture containing the titanate support contains a solvent suitable for use as disclosed herein (e.g., heptane). The mixture containing the metallized support may be heated and contacted with an alkaline aqueous solution to provide a mixture containing a hydrolyzed metallized support. The hydrolyzed metallized support may be dried to form a pre-catalyst.

[0062] In an alternative approach, a chromium-containing compound is contacted with a mixture comprising a hydrolyzed support prepared by liquid / liquid extraction using an alkaline aqueous solution to form a mixture comprising a hydrolyzed metallized support. The hydrolyzed metallized support may be dried to form a pre-catalyst.

[0063] In another alternative, a chromium-containing compound is contacted with a hydrolyzed precatalyst prepared by liquid / liquid extraction using an alkaline aqueous solution to form a precatalyst.

[0064] In any aspect of this disclosure, the method for preparing an olefin polymerization catalyst further comprises activating a precatalyst prepared as disclosed herein via a calcination step. In some aspects, the calcination of the precatalyst comprises heating the precatalyst in an oxidizing environment to produce the olefin polymerization catalyst. For example, the precatalyst can be calcined by heating it in the presence of air to a temperature in the range of about 400°C to about 1000°C; alternatively, about 500°C to about 900°C; or alternatively, about 500°C to about 850°C. The calcination of the precatalyst may additionally include maintaining the temperature of the precatalyst at about 400°C to about 1000°C in the presence of air; alternatively, about 500°C to about 900°C; or alternatively, about 500°C to about 850°C for a period of about 1 minute to about 24 hours; alternatively, about 1 minute to about 12 hours; alternatively, about 20 minutes to about 12 hours; alternatively, about 1 hour to about 10 hours; alternatively, about 3 hours to about 10 hours; or alternatively, about 3 hours to about 5 hours to produce an olefin polymerization catalyst.

[0065] During catalyst production, substances such as highly reactive volatile organic compounds (HRVOCs) may be emitted. HRVOCs play a role in ozone formation in ozone-deficient areas, i.e., areas that do not meet the Environmental Protection Agency's air quality standards for ground-level ozone. In one aspect of this disclosure, the olefin polymerization catalyst prepared as disclosed herein results in a reduction in the level of HRVOCs generated during the preparation of the olefin polymerization catalyst. For example, HRVOCs may comprise hydrocarbons, aromatic compounds, alcohols, ketones, or combinations thereof. In one aspect of this disclosure, HRVOCs comprise alcohols and olefins, with non-limiting examples including ethanol, propanol, butanol, ethylene, propylene, and butane.

[0066] The simplified reaction scheme in the accompanying figures illustrates that the hydroxyl groups and the Si-OH bonds within them on the silica support surface are replaced by Si-O-Ti bonds formed during the titanation reaction on the support. The figures also show that one equivalent of Ti(OiPr)₄ can react with no more than two hydroxyl groups, resulting in a titanated support containing numerous isopropanol groups (OiPr) bonded by Ti-O-iPr bonds. The Ti-O-iPr bonds remain intact throughout the catalyst preparation process until the high temperatures used to activate the catalyst are encountered during calcination. Undesirably, the breaking of Ti-O-iPr bonds yields isopropanol and promotes HRVOC emissions. In some cases, the isopropanol groups can be eliminated to produce HRVOC propylene. On one hand, contacting the pre-catalyst with a nitrogen-containing compound as disclosed herein can be effective for removing isopropanol groups from the support prior to the calcination step. In another aspect, the olefin polymerization catalysts disclosed herein are characterized in that HRVOC emissions are reduced by about 50% to about 95% compared to emissions from otherwise similar olefin polymerization catalysts prepared in the absence of nitrogen-containing compounds (e.g., wherein the pre-catalyst used to produce the olefin polymerization catalyst is not treated with an alkaline aqueous solution prior to activation by calcination as disclosed herein). Alternatively, HRVOC emissions from the olefin polymerization catalysts prepared herein are reduced by more than about 50% compared to HRVOC emissions from otherwise similar olefin polymerization catalysts prepared in the absence of nitrogen-containing compounds; alternatively, by more than about 75%; alternatively, by more than about 90%; or alternatively, by more than about 95%. In one aspect of this disclosure, after all processing steps are completed (i.e., after activation via calcination), the HRVOC emissions during the preparation of the type of olefin polymerization catalyst disclosed herein are less than about 5 wt% by weight of the total olefin polymerization catalyst; alternatively, less than about 2 wt%; alternatively, less than about 1 wt%; or alternatively, less than about 0.5 wt%.

[0067] The olefin polymerization catalysts disclosed herein are applicable to any olefin polymerization method using various types of polymerization reactors. In one aspect of this disclosure, the polymers of this disclosure are produced by any olefin polymerization method using various types of polymerization reactors. As used herein, a “polymerization reactor” includes any reactor capable of polymerizing olefin monomers to produce homopolymers and / or copolymers. The homopolymers and / or copolymers produced in the reactor may be referred to as resins and / or polymers. Various types of reactors include, but are not limited to, those reactors that may be referred to as batch, slurry, gas-phase, solution, high-pressure, tubular, autoclave, or other one and / or more reactors. Gas-phase reactors may comprise fluidized bed reactors or staged horizontal reactors. Slurry reactors may comprise vertical and / or horizontal loops. High-pressure reactors may comprise autoclaves and / or tubular reactors. Reactor types may include batch and / or continuous processes. Continuous processes may use batch and / or continuous product discharge or transfer. The process may also include partial or complete direct recycling of unreacted monomers, unreacted comonomers, olefin polymerization catalysts and / or cocatalysts, diluents and / or other materials from the polymerization process.

[0068] The polymerization reactor system disclosed herein may comprise one type of reactor or multiple reactors of the same or different types, operating in any suitable configuration. Polymer production in multiple reactors may include several stages in at least two separate polymerization reactors interconnected by a transfer system, such that polymer produced by a first polymerization reactor can be transferred to a second reactor. Alternatively, polymerization in multiple reactors may include manually or automatically transferring polymer from one reactor to one or more subsequent reactors for additional polymerization. Alternatively, multi-stage or multi-step polymerization may be carried out in a single reactor, with conditions in the reactor modified to allow different polymerization reactions to occur.

[0069] The desired polymerization conditions in one of the reactors may be the same as or different from the operating conditions of any other reactors involved in the overall process for producing the polymers of this disclosure. Multiple reactor systems may include any combination, including but not limited to multiple loop reactors, multiple gas-phase reactors, combinations of loop reactors and gas-phase reactors, multiple high-pressure reactors, and combinations of high-pressure reactors with loop reactors and / or gas-phase reactors. Multiple reactors may operate in series or in parallel. In one aspect of this disclosure, any arrangement and / or combination of reactors may be used to produce the polymers of this disclosure.

[0070] According to one aspect of this disclosure, the polymerization reactor system may comprise at least one loop slurry reactor. Such reactors are common and may comprise vertical or horizontal loops. Typically, a continuous process may comprise the continuous introduction of monomers, olefin polymerization catalysts, and / or diluents into the polymerization reactor and the continuous removal of a suspension containing polymer particles and diluents from the reactor. Monomers, diluents, olefin polymerization catalysts, and optionally any comonomers may be continuously fed into the loop slurry reactor, where polymerization occurs. The reactor effluent may be flashed to remove a liquid containing diluents from the solid polymer, monomers, and / or comonomers. Various techniques may be used for this separation step, including but not limited to flashing, which may include any combination of heating and depressurization; separation by cyclone action in a cyclone or hydrocyclone; separation by centrifugation; or other suitable separation methods.

[0071] Typical slurry polymerization processes (also known as particle formation processes) are disclosed, for example, in U.S. Patent Nos. 3,248,179, 4,501,885, 5,565,175, 5,575,979, 6,239,235, 6,262,191, and 6,833,415; each of these U.S. Patents is incorporated herein by reference in its entirety.

[0072] Diluents suitable for slurry polymerization include, but are not limited to, the monomers being polymerized and hydrocarbons that are liquid under reaction conditions. Examples of suitable diluents include, but are not limited to, hydrocarbons such as propane, cyclohexane, isobutane, n-butane, n-pentane, isopentane, neopentane, and n-hexane. Some ring polymerization reactions can occur under bulk conditions without the use of diluents. An example is the polymerization of propylene monomers as disclosed in U.S. Patent No. 5,455,314, which is incorporated herein by reference in its entirety.

[0073] According to another aspect of this disclosure, the polymerization reactor may comprise at least one gas-phase reactor. Such systems may employ a continuous recirculation stream containing one or more monomers, continuously circulated through a fluidized bed under polymerization conditions in the presence of an olefin polymerization catalyst. The recirculation stream may be drawn from the fluidized bed and recycled back into the reactor. Simultaneously, polymer products may be drawn from the reactor and new or fresh monomers may be added to replace the polymerized monomers. Such gas-phase reactors may comprise a process for multi-step gas-phase polymerization of olefins, wherein the olefins are polymerized in the gas phase of at least two independent gas-phase polymerization zones, while a polymer containing an olefin polymerization catalyst formed in a first polymerization zone is fed into a second polymerization zone. One type of suitable gas-phase reactor is disclosed in U.S. Patent Nos. 4,588,790, 5,352,749, and 5,436,304, each of which is incorporated herein by reference in its entirety.

[0074] According to another aspect of this disclosure, the high-pressure polymerization reactor may comprise a tubular reactor or an autoclave reactor. The tubular reactor may have several zones for adding fresh monomers, initiators, or olefin polymerization catalysts. Monomers may be entrained in an inert gas stream and introduced in one zone of the reactor. Initiators, olefin polymerization catalysts, and / or catalyst components may be entrained in the gas stream and introduced in another zone of the reactor. The gas streams may be mixed for polymerization. Heat and pressure may be suitably employed to obtain optimal polymerization reaction conditions.

[0075] According to another aspect of this disclosure, the polymerization reactor may comprise a solution polymerization reactor, wherein the monomer is contacted with the olefin polymerization catalyst composition by suitable stirring or other means. A carrier comprising an organic diluent or an excess of monomer may be used. If necessary, the monomer may be introduced into the vapor phase and contacted with the catalytic reaction products, with or without liquid material. The polymerization zone is maintained at the temperature and pressure that would cause the formation of the polymer in the reaction medium. Agitation may be employed to obtain better temperature control throughout the polymerization zone and to maintain a homogeneous polymerization mixture. Appropriate means are used to dissipate the exothermic heat of polymerization.

[0076] The polymerization reactors suitable for use in this disclosure may additionally include any combination of at least one raw material feed system, at least one feed system for olefin polymerization catalysts or catalyst components, and / or at least one polymer recovery system. Suitable reactor systems for use in this disclosure may additionally include systems for raw material purification, catalyst storage and preparation, extrusion, reactor cooling, polymer recovery, fractionation, recycling, storage, unloading, laboratory analysis, and process control.

[0077] Conditions controlled for polymerization efficiency and to provide polymer properties include, but are not limited to, temperature, pressure, the type and amount of olefin polymerization catalyst or co-catalyst, and the concentrations of various reactants. Polymerization temperature can affect catalyst productivity, polymer molecular weight, and molecular weight distribution. Suitable polymerization temperatures can be any temperature below the depolymerization temperature according to the Gibbs Free Energy Equation. Typically, depending on the type of polymerization reactor and / or polymerization process, this includes, for example, from about 60°C to about 280°C, and / or from about 70°C to about 110°C.

[0078] The appropriate pressure will also vary depending on the reactor and polymerization process. Pressures for liquid-phase polymerization in loop reactors are typically less than 1000 psig (6.9 MPa). Pressures for gas-phase polymerization are typically in the range of about 200 psig (1.4 MPa) to 500 psig (3.45 MPa). High-pressure polymerization in tubular reactors or autoclave reactors typically operates in the range of about 20,000 psig (138 MPa) to 75,000 psig (518 MPa). Polymerization reactors can also be operated in the supercritical region, which typically occurs at higher temperatures and pressures. Operating above the critical point (supercritical phase) indicated by the pressure / temperature diagram can offer advantages.

[0079] The concentrations of various reactants can be controlled to produce polymers with certain physical and mechanical properties. The proposed end-use product formed from the polymer and the method of forming said product can be varied to determine the desired end-product characteristics. Mechanical properties include, but are not limited to, tensile strength, flexural modulus, impact resistance, creep, stress relaxation, and hardness test values. Physical properties include, but are not limited to, density, molecular weight, molecular weight distribution, melting temperature, glass transition temperature, melt crystallization temperature, density, stereoregularity, crack propagation, short-chain branching, long-chain branching, and rheological measurements.

[0080] The concentrations of monomers, comonomers, hydrogen, cocatalysts, modifiers, and electron donors are generally important in producing specific polymer properties. Comonomers can be used to control product density. Hydrogen can be used to control product molecular weight. Cocatalysts can be used for alkylation, poison removal, and / or molecular weight control. Poison concentrations can be minimized because poisons can affect the reaction and / or otherwise influence polymer product properties. Modifiers can be used to control product properties, and electron donors can affect stereoregularity.

[0081] Polymers such as polyethylene homopolymers and copolymers of ethylene with other monoolefins can be produced using olefin polymerization catalysts prepared as described herein, in the manner described above. Polymers produced as disclosed herein can be formed into articles or end-use articles using techniques known in the art, such as extrusion, blow molding, injection molding, fiber spinning, thermoforming, and casting. For example, polymer resins can be extruded into sheets, which are then thermoformed into end-use articles such as containers, cups, plates, trays, toys, or components of another product. Examples of other end-use articles that can be formed from polymer resins include tubes, films, and bottles.

[0082] The method disclosed herein comprises contacting an olefin polymerization catalyst of the type described herein with an olefin monomer under conditions suitable for forming a polyolefin, and recovering the polyolefin. In one aspect, the olefin monomer is an ethylene monomer, and the polyolefin is an ethylene polymer (polyethylene).

[0083] The polyethylene prepared as described herein is characterized by a high-load melt index (HLMI) in the range of about 1 g / 10 min to about 500 g / 10 min; alternatively, about 3 g / 10 min to about 300 g / 10 min; alternatively, about 10 g / 10 min to about 100 g / 10 min; or alternatively, about 25 g / 10 min to about 50 g / 10 min. In another aspect, the polyethylene prepared as described herein is characterized by an HLMI that is about 1.1 to about 1.5 times that of a polymer produced using a otherwise similar olefin polymerization catalyst in the absence of nitrogen-containing compounds.

[0084] HLMI indicates the flow rate of molten polymer through a 0.0825-inch diameter orifice when subjected to a force of 21,600 g at 190°C, as determined according to Condition F of ASTM D1238-82.

[0085] Example

[0086] The following examples are given in the form of specific aspects of this disclosure and are used to demonstrate their practice and advantages. It should be understood that the examples are given by way of illustration and are not intended to limit this specification or the subsequent claims in any way.

[0087] In each of the following experiments, HA30W (a Cr / silica catalyst prepared by WR Grace) was dried at 200 °C and then acidified with anhydrous Ti(OiPr)4 in heptane and dried. The various samples were then treated as listed below before activation at 650 °C. The final catalyst contained 3% Ti.

[0088] Activity testing was conducted in a 2.2-liter steel reactor equipped with a marine agitator operating at 400 rpm. A steel-jacketed circulating water system surrounded the reactor, with its temperature controlled using steam and water heat exchangers. These were connected to an electronic feedback loop, allowing the reactor temperature to be maintained at + / - 0.5°C during the reaction.

[0089] Unless otherwise specified, a small amount (typically 0.01 to 0.10 g) of solid chromium catalyst is first charged into a dry reactor under nitrogen atmosphere. Next, approximately 0.25 g of sulfate-treated alumina (600 °C) is added as a poison scavenger. Then, 1.2 liters of liquid isobutane is added and the reactor is heated to a specified temperature, typically 105 °C. Finally, ethylene is added to the reactor to a constant pressure, typically 550 psig (3.8 MPa), which is maintained during the experiment. Stirring is permitted for a specified time, typically about one hour, and the activity is recorded by monitoring the ethylene flow rate into the reactor to maintain the set pressure.

[0090] After the allotted time, the ethylene flow is stopped, and the reactor is slowly depressurized and opened to recover the granular polymer powder. In all cases, the reactor is clean, with no indication of any wall fouling, coatings, or other forms of contamination. The polymer powder is then removed and weighed. Activity is specified as the number of grams of polymer produced per hour per gram of solid catalyst charged.

[0091] Example 1

[0092] The first series of experiments investigated the alkaline treatment capability of anhydrous titanate supports dissolved in solution to maintain titanate treatment of the support and provide effective titanate treatment for the catalyst. The results are listed in Table 1. Experiments 1.1 and 1.2 were comparative experiments and were not exposed to alkaline treatment. Experiment 1.3 used a titanate support prepared as described above. After treatment with Ti(OiPr)4, the liquid mixture containing the titanate support was exposed at 160°C to a mixture of MeOH and NH4OH vapors (70 / 30 volume ratio) for 24 hours by bubbling MeOH / NH4OH vapor through it. The melt index data from Experiment 1.3 show that alkaline treatment did not degrade catalyst performance but resulted in an increase in the HLMI value of greater than 10% relative to the comparative experiments.

[0093]

[0094]

[0095] Example 2

[0096] The next series of experiments investigated the alkaline treatment capability of the solid anhydrous titanate support to maintain the titanate on the support and provide effective titanate for the catalyst. In these experiments, the silica support used above was again titanated via the same procedure described above. This served as the alkaline catalyst for the finishing treatment experiments.

[0097] The results of different post-treatments are listed in Table 2. Comparative experiments (Experiment 2.1) were also conducted, in which no post-treatment of the catalyst was given. In Experiment 2.2, the solid titanate support was exposed to n-propanol vapor at 200 °C for 3 hours, and a loss of melt index potential was observed as a result. Propanol and other alcohols are believed to hydrolyze Si-O-Ti bonds, thereby compromising the effectiveness of Ti. In Experiment 2.3, the titanate support was washed in an aqueous NH4OH solution (5 wt%), then dried and calcined in a conventional manner. The HLMI value of the alkaline-washed catalyst was nearly 30% higher than that of the comparative experiment, indicating that alkaline washing suppressed the hydrolysis of Si-O-Ti bonds known to occur during calcination. In Experiment 2.4, the same procedure was again used to produce the titanate catalyst of Experiment 2.2. After washing the titanate support with an aqueous NH4OH solution, the catalyst of Experiment 2.4 was exposed to methanol vapor at 160 °C for 24 hours. The decrease in melt index potential observed between tests 2.3 and 2.4 can again be explained by the hydrolysis of the Si-O-Ti bonds; however, the decrease is not as severe as that observed in test 2.2, which does not include treatment of the titanate support with NH4OH hydroxide prior to prolonged exposure to hot alcohol vapors. Some of the protective effects of the NH4OH treatment remain unchanged, even though it evaporates during the heat treatment.

[0098] In Experiment 2.5, the titanate support was dry-mixed with urea prior to activation and was not washed with an aqueous NH4OH solution. This experiment was designed to capture ammonia produced by urea decomposition at high temperatures. However, urea decomposition only occurs at temperatures slightly above 100°C, and this method is ineffective at higher temperatures.

[0099]

[0100]

[0101] Example 3

[0102] The next series of experiments investigated whether washing the precatalyst with an aqueous alkali prior to activation hydrolyzes the residual Ti-isopropanol groups and reduces the amount of carbon retained on the precatalyst. Uncalcined precatalysts were obtained; Experiment 3.1 was performed without further treatment, and Experiment 3.2 was washed with an aqueous alkali. Residual carbon, nitrogen, hydrogen, and sulfur in both samples were analyzed by combustion analysis, and the results are shown in Table 3. Aqueous alkali washing resulted in a reduction of retained carbon by more than 90%. The retained carbon in isopropanol form is at least partially responsible for the emissions of VOCs and HRVOCs generated during the activation of the catalyst described herein. The experimental results indicate that washing the precatalyst with an aqueous alkali prior to activation reduces the amount of HRVOCs emitted during catalyst production as disclosed herein.

[0103]

[0104] Additional Disclosure

[0105] The following aspects of this disclosure are provided as non-limiting examples.

[0106] The first aspect is a method for preparing a precatalyst for hydrolysis, comprising: a) drying a silica support by heating it to a temperature in the range of about 150°C to about 250°C and maintaining the temperature of the silica support in the range of about 150°C to about 250°C for a period of about 1 hour to about 24 hours to form a dried support; b) contacting the dried support with titanium alkoxide (IV) to form a titanate support; c) drying the titanate support by heating it to a temperature in the range of about 50°C to about 200°C and maintaining the temperature of the titanate support in the range of about 50°C to about 200°C for a period of about 30 minutes to about 6 hours to form a dried titanate support; d) contacting the dried support with titanium alkoxide (IV) to form a titanate support. The dried titanate support is contacted with an alkaline aqueous solution containing about 3 wt% to about 20 wt% of a nitrogen-containing compound for a period of about 10 minutes to about 6 hours to form a mixture containing the hydrolyzed titanate support, wherein the weight ratio of the amount of alkaline aqueous solution to the amount of alkanolate titanium (IV) in the dried titanate support is about 30:1 to about 3:1; and e) the hydrolyzed titanate support is removed from the mixture containing the hydrolyzed titanate support, and the hydrolyzed titanate support is dried by heating the hydrolyzed titanate support to a temperature in the range of about 50°C to about 200°C and maintaining the temperature of the hydrolyzed titanate support in the range of about 50°C to about 200°C for a period of about 30 minutes to about 6 hours to form the hydrolyzed precatalyst.

[0107] The second aspect is the method according to the first aspect, further comprising: contacting a chromium-containing compound with at least one material selected from the group consisting of: the silica support, the dried support, the titanate support, the dried titanate support, the mixture comprising the hydrolyzed titanate support, and the hydrolyzed precatalyst; and calcining the precatalyst to form a catalyst by heating the precatalyst to a temperature in the range of about 400°C to about 1000°C and maintaining the temperature of the precatalyst in the range of about 400°C to about 1000°C for a period of about 1 minute to about 24 hours.

[0108] The third aspect is the method according to the second aspect, wherein, as determined by combustion analysis according to EPA Method 18-type / ASTM D1946, the amount of highly reactive volatile organic compounds (HRVOCs) emitted during the calcination of the precatalyst is reduced by approximately 80% to approximately 95% compared to the amount of HRVOCs emitted during the calcination of a otherwise similar precatalyst prepared in the absence of an alkaline aqueous solution.

[0109] The fourth aspect is the method according to the second aspect, wherein the amount of HRVOC emitted during the calcination of the precatalyst is less than about 1 wt%, as determined by combustion analysis according to EPA Method 18-Type / ASTM D1946.

[0110] The fifth aspect is a method according to any one of the preceding four aspects, wherein the nitrogen-containing compound comprises amide, amidine, amine, diamine, triamine, amino acid, ammonium hydroxide, formamide, hydrazine, hydroxylamine, imidazole, piperazine, piperidine, pyrazine, pyrazole, pyridine, pyrimidine, pyrrole, urea, or combinations thereof.

[0111] The sixth aspect is a method according to any one of the preceding five aspects, wherein the nitrogen-containing compound has structure 1, structure 2, structure 3 or structure 4: wherein each R 1 Each R 2 and each R 3 Independently hydrogen, a C1 to C6 organic group, or a C1 to C6 aryl group; each R 4 It is CH3 or C2H5; and R 5 It can be hydrogen, CH3, OH or OCH3.

[0112]

[0113] The seventh aspect is a method according to any one of the preceding six aspects, wherein the nitrogen-containing compound comprises ammonia, ammonium hydroxide, tetraethylammonium hydroxide, tetramethylammonium hydroxide, hydrazine, hydroxylamine, triethylamine, trimethylamine, acetamide, creatine, 1,4-diazabicyclo[2.2.2]octane (DABCO), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), N,N -Diisopropylethylamine (DIPEA), dimethyl carbamate, formamide, methylformamide, dimethylformamide, dimethylglycine, 1,4-dimethylpiperazine (DMP), 1,3-dimethylurea, imidazole, piperazine, piperidine, pyrazine, pyrazole, pyridine, pyrimidine, pyrrole, tetramethylethylenediamine (TMEDA), triazine, 1,3,5-triazacyclohexane, 1,3,5-trimethyl-1,3,5-triazacyclohexane (TMTAC), or combinations thereof.

[0114] The eighth aspect is a method according to any one of the preceding seven aspects, wherein the alkanolate titanium (IV) comprises titanium ethoxide (IV), titanium isopropoxide (IV), titanium n-propoxide (IV), titanium n-butoxide (IV), titanium isobutoxide (IV), or a combination thereof.

[0115] The ninth aspect is a method according to any one of the preceding eight aspects, wherein the alkanolate titanium (IV) comprises isopropoxide titanium (IV).

[0116] The tenth aspect is the method according to any one of the preceding nine aspects, wherein the silica support is characterized by being approximately 100 meters long. 2 / gram to approximately 1000 meters 2 / gram of surface area and approximately 1.0 cm 3 / gram to approximately 2.5 cm 3 / gram of pore volume.

[0117] The eleventh aspect is the method according to any one of the second to tenth aspects, wherein the chromium-containing compound comprises chromium trioxide, chromium acetate, chromium nitrate, tert-butyl chromate, dicyclopentadienyl chromium (II), chromium acetylacetonate (III), or a combination thereof.

[0118] The twelfth aspect is the method according to any one of the second to eleventh aspects, wherein the amount of titanium present in the catalyst is in the range of about 0.01% to about 10% of the total weight of the catalyst.

[0119] The thirteenth aspect is the method according to any one of the second to twelfth aspects, wherein the amount of chromium present in the catalyst is in the range of about 0.01% to about 10% of the total weight of the catalyst.

[0120] The fourteenth aspect is a method for forming an ethylene polymer, comprising contacting a catalyst prepared by any one of the methods according to the second to twelfth aspects with an ethylene monomer under conditions suitable for forming the ethylene polymer, and recovering the ethylene polymer.

[0121] The fifteenth aspect is the method according to the fourteenth aspect, wherein the high-load melt index (HLMI) of the ethylene polymer is about 10% to about 100% higher than that of the ethylene polymer produced by utilizing a catalyst that is otherwise similar in the absence of an alkaline aqueous solution.

[0122] The sixteenth aspect is a method for preparing a pre-catalyst for hydrolysis, comprising: a) drying a silica support by heating it to a temperature in the range of about 150°C to about 250°C and maintaining the temperature of the silica support in the range of about 150°C to about 250°C for a period of about 1 hour to about 24 hours to form a dried support; b) contacting the dried support with titanium alkoxide (IV) to form a titanate support; c) heating the titanate support to a temperature in the range of about 50°C to about 200°C and maintaining the temperature in the range of about 50°C to about 200°C while contacting the titanate support with an alkaline material for a period of about 2 hours to about 48 hours; d) stopping the contact between the titanate support and the alkaline material to provide a hydrolyzed support at a temperature in the range of about 50°C to about 200°C; and e) maintaining the temperature of the hydrolyzed support in the range of about 50°C to about 200°C for a period of about 30 minutes to about 6 hours to form the pre-catalyst for hydrolysis.

[0123] The seventeenth aspect is the method according to the sixteenth aspect, further comprising contacting a chromium-containing compound with at least one material selected from the group consisting of: the silica support, the dried support, the titanate support, the hydrolyzed support, and the hydrolyzed precatalyst; and calcining the precatalyst to form a catalyst by heating the precatalyst to a temperature in the range of about 400°C to about 1000°C and maintaining the temperature of the precatalyst in the range of about 400°C to about 1000°C for a period of about 1 minute to about 24 hours.

[0124] The eighteenth aspect is the method according to the seventeenth aspect, wherein, as determined by combustion analysis according to EPA Method 18-Type / ASTM D1946, the amount of HRVOC emitted during the calcination of the precatalyst is reduced by about 80% to about 95% compared to the amount of HRVOC emitted during the calcination of a otherwise similar precatalyst prepared in the absence of alkaline materials.

[0125] The nineteenth aspect is the method according to the seventeenth aspect, wherein the amount of HRVOC emitted during the calcination of the precatalyst is less than about 1 wt%, as determined by combustion analysis according to EPA Method 18-Type / ASTM D1946.

[0126] The twentieth aspect is the method according to the sixteenth aspect, wherein the alkaline material comprises a vapor associated with an alkaline liquid, wherein the alkaline liquid comprises an aqueous solution of a nitrogen-containing compound and optionally an alcohol, wherein the amount of the nitrogen-containing compound in the aqueous solution is from about 3 wt% to about 20 wt%, wherein the volume 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.

[0127] The twenty-first aspect is the method according to the sixteenth aspect, wherein the alkaline material is an alkaline aqueous solution containing about 3 wt% to about 20 wt% of a nitrogen-containing compound, wherein the weight ratio of the amount of the alkaline aqueous solution to the amount of titanium alkoxide (IV) in the titanate support is about 30:1 to about 3:1.

[0128] The twenty-second aspect is a method according to any one of aspects sixteen to twenty-one, wherein the alkaline material comprises amide, amidine, amine, diamine, triamine, amino acid, ammonium hydroxide, formamide, hydrazine, hydroxylamine, imidazole, piperazine, piperidine, pyrazine, pyrazole, pyridine, pyrimidine, pyrrole, urea, or combinations thereof.

[0129] The twenty-third aspect is a method according to any one of aspects sixteen to twenty-two, wherein the alkaline material has structure 1, structure 2, structure 3 or structure 4: wherein each R 1 Each R 2 and each R 3 Independently hydrogen, a C1 to C6 organic group, or a C1 to C6 aryl group; each R 4 It is CH3 or C2H5; and R 5 It can be hydrogen, CH3, OH or OCH3.

[0130]

[0131] The twenty-fourth aspect is the method according to any one of aspects sixteen to twenty-three, wherein the alkaline material comprises ammonia, ammonium hydroxide, tetraethylammonium hydroxide, tetramethylammonium hydroxide, hydrazine, hydroxylamine, triethylamine, trimethylamine, acetamide, creatine, 1,4-diazabicyclo[2.2.2]octane (DABCO), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). N,N-Diisopropylethylamine (DIPEA), dimethyl carbamate, formamide, methylformamide, dimethylformamide, dimethylglycine, 1,4-dimethylpiperazine (DMP), 1,3-dimethylurea, imidazole, piperazine, piperidine, pyrazine, pyrazole, pyridine, pyrimidine, pyrrole, tetramethylethylenediamine (TMEDA), triazine, 1,3,5-triazacyclohexane, 1,3,5-trimethyl-1,3,5-triazacyclohexane (TMTAC), or combinations thereof.

[0132] The twenty-fifth aspect is a method according to any one of the sixteenth to twenty-fourth aspects, wherein the alkanolate titanium (IV) comprises titanium ethoxide (IV), titanium isopropoxide (IV), titanium n-propoxide (IV), titanium n-butoxide (IV), titanium isobutoxide (IV), or a combination thereof.

[0133] The twenty-sixth aspect is the method according to the seventeenth aspect, wherein the amount of chromium present in the catalyst is in the range of about 0.01% to about 10% of the total weight of the catalyst.

[0134] The twenty-seventh aspect is a method for preparing a catalyst, comprising: a) drying a chromated silica support by heating it to a temperature in the range of about 150°C to about 250°C and maintaining the temperature of the chromated silica support in the range of about 150°C to about 250°C for a period of about 1 hour to about 24 hours to form a dried chromated silica support; b) contacting the dried chromated silica support with titanium alkoxide (IV) to form a metallized support; c) drying the metallized support by heating it to a temperature in the range of about 50°C to about 200°C and maintaining the temperature of the metallized support in the range of about 50°C to about 200°C for a period of about 30 minutes to about 6 hours to form a dried metallized support; d) contacting the dried metallized support with an alkaline aqueous solution containing about 3 wt% to about 20 wt% of a nitrogen-containing compound for about 1 hour to about 24 hours to form a dried metallized support. The process involves: e) forming a mixture comprising a hydrolyzed metallized support over a period of 10 minutes to 6 hours, wherein the weight ratio of the amount of alkaline aqueous solution to the amount of alkanolate titanium (IV) in the dried metallized support is from about 30:1 to about 3:1; e) removing the hydrolyzed metallized support from the mixture comprising the hydrolyzed metallized support and drying the hydrolyzed metallized support by heating it to a temperature in the range of about 50°C to about 200°C and maintaining the temperature of the hydrolyzed metallized support in the range of about 50°C to about 200°C for a period of about 30 minutes to about 6 hours to form a precatalyst; and f) calcining the precatalyst by heating it to a temperature in the range of about 400°C to about 1000°C and maintaining the temperature of the precatalyst in the range of about 400°C to about 1000°C for a period of about 1 minute to about 24 hours to form the catalyst.

[0135] The twenty-eighth aspect is a method for preparing a catalyst, comprising: a) drying a silica support by heating it to a temperature in the range of about 150°C to about 250°C and maintaining the temperature of the silica support in the range of about 150°C to about 250°C for a period of about 1 hour to about 24 hours to form a dried support; b) contacting the dried support with titanium alkoxide (IV) to form a titanate support; c) heating the titanate support to a temperature in the range of about 50°C to about 200°C. The titanate support is dried by maintaining the temperature within a range of about 50°C to about 200°C for about 30 minutes to about 6 hours to form a dried titanate support; d) the dried titanate support is contacted with an alkaline aqueous solution containing about 3 wt% to about 20 wt% of a nitrogen-containing compound for about 10 minutes to about 6 hours to form a mixture containing hydrolyzed titanate support, wherein the amount of alkaline aqueous solution is proportional to the amount of alkanolate (IV) in the dried titanate support. The mass ratio is from about 30:1 to about 3:1; e) removing the hydrolyzed titanate support from the mixture containing the hydrolyzed titanate support, and drying the hydrolyzed titanate support by heating it to a temperature in the range of about 50°C to about 200°C and maintaining the temperature of the hydrolyzed titanate support in the range of about 50°C to about 200°C for a period of about 30 minutes to about 6 hours to form a hydrolyzed precatalyst; f) mixing the chromium-containing compound with at least the following groups. A material contact to form a precatalyst: the silica support, the dried support, the titanate support, the dried titanate support, the mixture comprising the hydrolyzed titanate support, and the hydrolyzed precatalyst; and g) calcining the precatalyst to form the catalyst by heating the precatalyst to a temperature in the range of about 400°C to about 1000°C and maintaining the temperature of the precatalyst in the range of about 400°C to about 1000°C for a period of about 1 minute to about 24 hours.

[0136] The twenty-ninth aspect is a method for preparing a catalyst, comprising: a) drying a chromated silica support by heating it to a temperature in the range of about 150°C to about 250°C and maintaining the temperature of the chromated silica support in the range of about 150°C to about 250°C for a period of about 1 hour to about 24 hours to form a dried chromated silica support; b) contacting the dried chromated silica support with titanium alkoxide (IV) to form a metallized support; c) heating the metallized support to a temperature in the range of about 50°C to about 200°C and maintaining the temperature in the range of about 50°C to about 200°C, while simultaneously metallizing the support... The process involves: d) contacting the support with the gaseous solution material for approximately 2 hours to approximately 48 hours; d) ceasing contact between the metallized support and the gaseous solution to provide a hydrolyzed metallized support at a temperature ranging from approximately 50°C to approximately 200°C; e) maintaining the temperature of the hydrolyzed metallized support at approximately 50°C to approximately 200°C for approximately 30 minutes to approximately 6 hours to form a precatalyst; and f) calcining the precatalyst to form the catalyst by heating it to a temperature ranging from approximately 400°C to approximately 1000°C and maintaining the temperature of the precatalyst at approximately 400°C to approximately 1000°C for approximately 1 minute to approximately 24 hours.

[0137] The thirtieth aspect is a method for preparing a catalyst, comprising: a) drying a silica support by heating it to a temperature in the range of about 150°C to about 250°C and maintaining the temperature of the silica support in the range of about 150°C to about 250°C for a period of about 1 hour to about 24 hours to form a dried support; b) contacting the dried support with titanium alkoxide (IV) to form a titanate support; c) heating the titanate support to a temperature in the range of about 50°C to about 200°C and maintaining the temperature in the range of about 50°C to about 200°C, while contacting the titanate support with a gas phase solution for a period of about 2 hours to about 48 hours; d) stopping the contact between the titanate support and the gas phase solution to improve the catalyst's properties. The catalyst is prepared by: e) providing a support for hydrolysis at a temperature ranging from about 50°C to about 200°C; f) maintaining the temperature of the hydrolyzed support at a temperature ranging from about 50°C to about 200°C for a period of about 30 minutes to about 6 hours to form a hydrolyzed precatalyst; f) contacting a chromium-containing compound with at least one material selected from the group consisting of: the silica support, the dried support, the titanate support, the hydrolyzed support, and the hydrolyzed precatalyst; and g) calcining the precatalyst by heating it to a temperature ranging from about 400°C to about 1000°C and maintaining the temperature of the precatalyst at a temperature ranging from about 400°C to about 1000°C for a period of about 1 minute to about 24 hours to form the catalyst.

[0138] Unless otherwise specifically indicated, the terms "a / an" and "described" are intended to include multiple / variable alternatives, such as at least one / variable. In this document, while methods and processes are described by way of "comprising" various components or steps, methods and processes may also be described as "substantially consisting of various components or steps" or "consisting of various components or steps." Specific features of the disclosed subject matter may be disclosed as follows: feature X may be A, B, or C. It is also contemplated that, for each feature, the statement may also be expressed as a list of alternatives, such that the statement "feature X is A, alternatively B, or alternatively C" is also an aspect of this disclosure, whether or not the statement is explicitly stated.

[0139] While various aspects of this disclosure have been shown and described, modifications can be made thereto by those skilled in the art without departing from the spirit and teaching of this disclosure. The aspects of this disclosure described herein are merely exemplary and not intended to be limiting. Many variations and modifications of this disclosure are possible and within the scope of this disclosure. Where a numerical range or limitation is expressly specified, such expression of range or limitation should be understood to include iterative ranges or limitations of the same quantity falling within the expressly specified range or limitation (e.g., "about 1 to about 10" includes 2, 3, 4, etc.; "greater than 0.10" includes 0.11, 0.12, 0.13, etc.). The use of the term "optionally" relative to any element in the claims is intended to mean that a principal element is required or alternatively not required. Both alternatives are intended to be within the scope of the claims. The use of broad terms such as "comprising," "including," and "having" should be understood to be supported by narrower terms such as "consisting of," "substantially consisting of," "mainly composed of," etc.

[0140] Therefore, the scope of protection is not limited to the description stated above, but is limited only by the following claims, which include all equivalents of the subject matter of the claims. Each and every claim is incorporated herein as an aspect of this disclosure. Therefore, the claims are additional descriptions and supplements to aspects of this disclosure. The references in this disclosure are not an admission that they are prior art to this disclosure, especially any references with publication dates after the priority date of this application. All patents, patent applications and publications cited herein are incorporated herein by reference to the extent that they provide exemplary, procedural or other details to those stated herein.

[0141] All publications, patent applications, and patents mentioned herein are incorporated herein by reference in their entirety. In the event of any conflict, this specification (including definitions) shall prevail. With respect to all scopes disclosed herein, even if no specific combination is specifically listed, such scopes are intended to include any combination of the mentioned upper and lower limits.

Claims

1. A pre-catalyst for hydrolysis, prepared by a process comprising: (i) a dried silica support, wherein the dried silica support has a weight loss of less than 3 wt% after drying; (ii) contact with a titanium-containing compound containing titanium alkoxide (IV) to form a titanate-oxidized support; and contact the titanate-oxidized support with (iii) an alkaline aqueous solution containing 3 wt% to 20 wt% of a nitrogen-containing compound based on the total weight of the alkaline aqueous solution. The nitrogen-containing compound comprises ammonium hydroxide, tetraethylammonium hydroxide, tetramethylammonium hydroxide, or a combination thereof; and The hydrolyzed titanate support is removed from the alkaline aqueous solution to form the hydrolyzed precatalyst.

2. The precatalyst for hydrolysis according to claim 1, wherein the alkoxide titanium (IV) comprises titanium ethanol (IV), titanium isopropoxide (IV), titanium n-propoxide (IV), titanium n-butoxide (IV), titanium isobutoxide (IV), or a combination thereof.

3. The precatalyst for hydrolysis according to claim 1, wherein the titanium-containing compound is titanium isopropoxide (IV).

4. The precatalyst for hydrolysis according to claim 1, wherein the amount of titanium present in the olefin polymerization catalyst is in the range of 0.01 wt% to 10.0 wt% based on the weight of the olefin polymerization catalyst; wherein the olefin polymerization catalyst is prepared by heating the precatalyst in the presence of air to a temperature in the range of 400°C to 1000°C and maintaining the temperature for a period of 1 minute to 24 hours to form the olefin polymerization catalyst.

5. The pre-catalyst for hydrolysis according to claim 1, wherein the weight ratio of the alkaline aqueous solution to the titanium-containing compound is 100:1 to 1:

1.

6. The precatalyst for hydrolysis according to claim 1, wherein the alkaline aqueous solution further comprises a co-solvent.

7. The precatalyst for hydrolysis according to claim 6, wherein the volume ratio of the co-solvent to water is in the range of 1:20 to 20:

1.

8. The pre-catalyst for hydrolysis according to claim 1, wherein the surface area of ​​the dried silica support is 100 m². 2 / g to 1000m 2 Within the range of / g.

9. The precatalyst for hydrolysis according to claim 1, wherein the pore volume of the dried silica support is 1.0 cm³. 3 / g to 2.5cm 3 Within the range of / g.

10. The precatalyst for hydrolysis according to claim 1, wherein the dried silica contains more than 50 wt% silica based on the total weight of the dried silica support.

11. A method for preparing a precatalyst for hydrolysis, comprising: a) Drying the silica carrier by heating it to a temperature in the range of 150°C to 250°C and maintaining the temperature of the silica carrier in the range of 150°C to 250°C for a period of 1 hour to 24 hours to form a dried carrier. b) Contact the dried support with a titanium-containing compound containing titanium alkoxide (IV) to form a titanate support; c) The titanate support is dried by heating it to a temperature in the range of 50°C to 200°C and maintaining the temperature of the titanate support in the range of 50°C to 200°C for a period of 30 minutes to 6 hours to form a dried titanate support. d) Contacting the dried titanate support with a gas-phase mixture for a period of 10 minutes to 6 hours to form a mixture comprising the hydrolyzed titanate support, the gas-phase mixture comprising vapor associated with an alkaline liquid containing 3 wt% to 20 wt% of a nitrogen-containing compound, wherein the amount of alkaline liquid used is sufficient to achieve an equimolar ratio of the nitrogen-containing compound to the titanate compound in the range of 100:1 to 1:2; wherein the nitrogen-containing compound comprises ammonium hydroxide, tetraethylammonium hydroxide, tetramethylammonium hydroxide, or a combination thereof; and e) Remove the hydrolyzed titanate support from the mixture containing the hydrolyzed titanate support, and dry the hydrolyzed titanate support by heating it to a temperature in the range of 50°C to 200°C and maintaining the temperature of the hydrolyzed titanate support in the range of 50°C to 200°C for a period of 30 minutes to 6 hours to form the hydrolyzed precatalyst.

12. The method of claim 11, wherein the alkanolate titanium (IV) comprises isopropoxide titanium (IV).

13. The method of claim 11, wherein the amount of titanium present in the olefin polymerization catalyst is in the range of 0.01 wt% to 10.0 wt% based on the total weight of the olefin polymerization catalyst; wherein the olefin polymerization catalyst is prepared by heating the pre-catalyst in the presence of air to a temperature in the range of 400°C to 1000°C and maintaining the temperature for a period of 1 minute to 24 hours to form the olefin polymerization catalyst.

14. The method of claim 11, wherein the alkaline liquid comprises methanol, ethanol, n-propanol, isopropanol, or a combination thereof.

15. The method of claim 11, wherein the alkaline liquid comprises an aqueous solution of a nitrogen-containing compound and optionally an alcohol, wherein the amount of the nitrogen-containing compound in the aqueous solution is from 3 wt.% to 20 wt.%, wherein the volume ratio of the aqueous solution to the alcohol is from 7:3 to 3:7, and wherein the alcohol is methanol, ethanol, n-propanol, isopropanol, or a combination thereof.

16. The method of claim 11, wherein the temperature of the alkaline liquid, the vapor, or both is in the range of 120°C to 200°C.

17. A precatalyst for hydrolysis, comprising: (i) a dried silica support, wherein the dried silica support has a weight loss of less than 3 wt% after drying; (ii) a titanium-containing compound comprising titanium alkoxide (IV); and (iii) an alkaline aqueous solution comprising 3 wt% to 20 wt% of a nitrogen-containing compound based on the total weight of the alkaline aqueous solution; wherein the nitrogen-containing compound comprises ammonium hydroxide, tetraethylammonium hydroxide, tetramethylammonium hydroxide, or a combination thereof.

18. The precatalyst for hydrolysis according to claim 17, wherein the alkanolate titanium (IV) comprises isopropoxide titanium (IV).

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