RS49659B - PROPYLENE POLYMERIZATION CATALYST AND ITS USE - Google Patents

Abstract

Propylene polymerization catalyst having the following components: (A) A solid catalyst component made by dissolving magnesium halide in a solvent system consisting of an organic epoxy compound, an organic phosphorus compound and an inert diluent to reward a homogeneous solution: the homogeneous solution is mixed with titanium halide to form the mixture: the solid from the mixture is precipitated in the presence of a precipitating agent: the solid is treated with a polycarboxylic acid ester to adsorb the ester to the solid: and the ester adsorbed onto the solid is treated with titanium halide and inert diluent, where the precipitant is selected from organic anhydrides, organic acids, ethers and ketones, and where, based on the mole of magnesium halide, the amount of organic epoxy compound is 0.2 to 5 moles, and the molar ratio of the organic epoxy compound according to the organic phosphorus unit is from 0.5 to 1.6, (B) An organic aluminum compound having the formula AlRnX3-n wherein each R is independently hydrogen or a hydrocarbyl group having 1-20 carbon atoms, X is halogen, and the number is from 1 to 3: (C ) An organic silicon compound having the formula Rn (Si (OR ') 4-n wherein R and R' are each independently selected from alkyl, cycloalkyl, aryl and haloalkyl in an integer from 0 to 3:

Description

This invention relates to a catalyst for the polymerization of propylene and to a process using the same in the polymerization of propylene.

It is known that the particle size, particle shape and particle size distribution of the catalyst have an important influence on the properties of the produced polymer using the catalyst. The balance of tunable particle size, desirable particle shape, and narrow catalyst particle size distribution is a feature that all catalyst manufacturers expect. However, it is difficult to maintain good particle size and narrow catalyst particle size distribution as the catalyst particle size increases.

Different polymerization processes on a commercial scale require an appropriate catalyst particle size. Therefore, there is a need in technology to adjust the catalyst particle size.

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U.S. patent no. 4,784,983 discloses a catalytic system for olefin polymethization consisting of components (A), (B) and (C). Component (A) is prepared by dissolving magnesium halide in a solvent mixture of an organic epoxy compound and an organic phosphorus compound to yield a homogeneous solution: the homogeneous solution is mixed with liquid titanium halide,: a precipitation aid such as carboxylic acid anhydrides, organic carboxylic acids, ethers and ketones is added to yield a precipitate: at least one polycarboxylic acid ester is added when a precipitate appears: and the precipitate is separated from the mixture and separated the precipitate is treated in an inert diluent using titanium halide or a mixture of titanium halides. The activity of the catalytic system of the patent is very high. The resulting polymer using the catalytic system has very high stereospecificity and a narrow particle size distribution.

However, the main problem with the catalytic system is that it is difficult to adjust the catalyst particle size. Particles with an irregular shape, such as a needle or similar to a date core, are formed when coarsely shaped catalyst particles are made using the process of U.S. Pat. patent no. 4, 784, 983, especially in factory-scale industrial production. The presence of irregularly shaped catalyst particles deteriorates the properties of the resulting polymer, and can stop the catalyst feed or the system for discharging the resulting polymer.

The above U.S. patent describes that, calculated per mole of magnesium halide, the added amount of epoxy compounds in the magnesium halide solution is about 0.1-10.0 moles and the added amount of organic phosphorus compounds is about 0.1-3.0 moles, which corresponds to a molar ratio of epoxy compounds to organic phosphorus compounds of about 0.033-100 (see column 2, lines 63-68). But, in all Applications of the patent description, 0.05 mol of anhydrous magnesium chloride, 75 ml of toluene, 0.1 mol of epoxy chloropropane and 0.03 mol of tributyl phosphate are used, whereby this corresponds to a molar ratio of epoxy chloropropane to tributyl phosphate of 3.3.

The inventors found that the use of a large amount of organic epoxy compounds is the main cause of the formation of irregularly shaped catalyst particles, and the catalyst particle size can be adjusted by changing the amount of inert diluent added to the solvent mixture or magnesium halide dissolution system at a low ratio of organic epoxy compound to organic phosphorus compound.

Therefore, the particle shape, particle size, and particle size distribution of the propylene polymerization catalyst can be controlled by adjusting the ratio of organic epoxy compounds to organic phosphorus compounds and the amount of inert diluent used. The invention was perfected based on such knowledge.

BRIEF DESCRIPTION OF THE INVENTION

This invention provides a catalyst for the polymerization of propylene consisting of the following components: (A) A solid catalyst component which is prepared by dissolving magnesium halide in a solvent system consisting of an organic epoxy compound, an organic phosphorus compound and an inert diluent to form a homogeneous solution: the homogeneous solution is mixed with titanium halide to form a mixture: from the mixture a solid is precipitated in the presence of a precipitation aid: the solid is treated with polycarboxylic acid ester to adsorb the ester to the solid: and the solid to which the ester is adsorbed is treated with titanium halide and an inert diluent,

wherein the auxiliary agent for deposition is selected from organic anhydrides, organic acids, ethers and ketones, and wherein calculated per mole of magnesium halide, the amount of organic epoxy compound is from 0.2 to 5 moles, and the molar ratio of organic epoxy compound to organic phosphorus compound is from 0.5 to 1.6: (B) An organic achymium compound having the formula AJRnX3.where each R is independently a hydrogen or a hydrocarbyl group having 1-20 carbon atoms, X is

halogen, and its number from 1 to 3:

(C) An organosilicon compound having the formula RnSi(OR')4.n where Ri R' is each independently selected from alkyl, cycloalkyl, aryl, and haloalkyl and is an integer from

0 to 3:

where the ratio of component (B) to component (A), measured as the molar ratio of aluminum to titanium, is from 5 to 1000, and the ratio of component (C) to component (A), measured as the molar ratio of silicon to titanium, is from 2 to 100.

This invention also provides a process for the use of a catalyst in the polymerization of propylene.

DETAILED DESCRIPTION OF THE INVENTION

In the proposed embodiment, component (A) of the solid catalyst is produced by the following process. The magnesium halide is first dissolved with stirring in a solvent system consisting of an organic epoxy compound, an organic phosphorus compound and an inert diluent at a temperature of 0 to 100 °C, preferably 30 to 70 °C to yield a homogeneous solution. The homogeneous solution is then mixed with titanium halide at a temperature of -35 to 60°C, preferably from -30 to 5°C in the presence of a precipitation aid to precipitate the mixture. A polycarboxylic acid ester is added to the mixture after or before the solid settles to adsorb at least a portion of the ester onto the solid. The temperature of the resulting mixture is raised to 60~110 °C to form a suspension, the suspension is stirred at that temperature for 10 minutes to 10 hours, then the solid matter is precipitated from the suspension. After separation, the separated solid is treated with titanium halide and an inert solvent, then washed with toluene and hexane to obtain component (A) of the solid catalyst.

Suitable magnesium halides include magnesium halides such as magnesium chloride, magnesium bromide and magnesium iodide: magnesium halide complex with water or alcohol: a magnesium halide derivative where the halogen atom is replaced by a hydrocarboxy or halohydrocarboxylic group: and the like.

Suitable organic epoxy compounds include aliphatic olefin oxides, aliphatic diolefins, halogenated aliphatic olefins, and halogenated aliphatic diolefins, glycidyl ethers, cyclic ethers and the like having 2-8 carbon atoms. Examples of suitable organic epoxy compounds are ethylene oxide, propylene oxide, butylene oxide, butadiene dioxide, epoxy chloropropane, methylglycidyl ether, diglycidyl ether, tetrahydrofuran, and the like.

Suitable organophosphorus compounds include hydrocarbyl esters of phosphoric acid or phosphoric acid, e.g. trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, trimethyl phosphite, triethyl phosphite, tributyl phosphite, triphenyl phosphite and the like.

Suitable inert diluent dissolves hexane, heptane, octane, benzene, toluene, xylene, 1,2-dichloroethane, chlorobenzene and other hydrocarbons or halohydrocarbons.

The amounts of magnesium halide solution components are as follows: calculated per mole of magnesium halide, the amount of organic epoxy compound is from 0.2 to 5 moles, preferably from 0.5 to 2 moles, the molar ratio of organic epoxy compound to organic phosphorus compound is from 0.5 to 1.6, preferably from 0.9 to 1.4 and the amount of inert diluent is from 1,200 to 2,400 ml, preferably 1,400 to 2,000 ml.

The titanium halide used in the manufacture of component (A) of the solid catalyst of the invention is a compound having the formula TiX„(OR)4_where X is halogen, each R is independently hydrocarbyl and n is an integer from 0 to 4. Examples of compounds are titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, tetrabutoxy titanium, tetraethoxy titanium, chlorotriethoxy titanium, dichlorodiethoxy titanium, trichloroethoxy titanium and the like.

The amount of titanium halide used is from 0.5 to 150 moles, primarily from 1 to 20 moles, calculated per mole of magnesium halide.

The deposition aid according to this invention includes organic acid anhydrides, organic acids, ketones, ethers and any combination thereof, such as acetic anhydride, phthalic anhydride, succinic anhydride, maleic anhydride, pyromellitic dianhydride, acetic acid, propionic acid, butyric acid, acrylic acid, raethacrylic acid, acetone, methyl ethyl ketone, benzophenone, dimethyl ether, diethyl ether, dipropyl ether, dibutyl ether, diamyl ether and the like.

The amount of precipitation aid is from 0.03 to 1.0 moles, preferably from 0.05 to 0.4 moles, calculated per mole of magnesium halide.

A polycarboxylic acid ester suitable for this invention includes esters of aliphatic and aromatic polycarboxylic acids. Examples of these esters include diethyl malonate, diethyl adipate, dibutyl adipate, diethyl sebacate, dibutyl sebacate, di-limi-methyl 1 phthalate, di-isobutyl phthalate, di-isooctyl phthalate, diethyl maleate, di-n-butyl maleate, diethyl naphthalene dicarboxylate, dibutyl naphthalene dicarboxylate, triethyl trimellitate, tributyl trimethylate, triethyl heinimelitate, tributyl hemimelitate, tetraethyl pyromelitate, tetrabutyl pyromellitate, and the like.

The amount of polycarboxylic acid ester used is from 0.0019 to 0.01 mole, preferably from 0.0040 to 0.0070 mole per mole of magnesium halide.

Component (B) is an organoaluminum compound having the formula AlRnX3.n-, where each R is independently hydrogen, or a hydrocarbon group having 1-20 carbon atoms, primarily an alkyl, aralkyl, or aryl group: X is halogen, primarily chlorine or bromine: and n' is a number from 1 to 3. Examples of compounds are tnalkyl aluminum compounds such as trimethyl aluminum, triethyl aluminum, tri-isobutyl aluminum, and trioctyl aluminum: hydrogenated alkyl aluminums such as diethyl aluminum ludride and di-isobutyl aluminum hydride: halogenated alkyl aluminums such as diethyl aluminum chloride, di-isobutyl aluminum chloride, sesquiethyl aluminum sesquichlonde and ethyl aluminum dichlonde: where triethyl aluminum and tri-isobutyl aluminum are assumed.

Component (C) is an organosilicon compound having the formula

R"" Si(OR')4 wherein n' is an integer from 0 to 3: R and R' are each independently an alkyl, cycloalkyl, anl, or haloalkyl group. Examples of such compounds are trimethyl methoxysilane, trimethyl ethoxysilane, methyl cyclohexyl dimethoxy silane, dibutyl dimethoxy silane, dimethyl dimethoxysilane, dimethyl diethoxysilane, diphenyl dimethoxysilane, diphenyl diethoxysilane, phenyl triethoxysilane, phenyl trimethoxysilane, and the like.

In the catalyst of the invention, the molar ratio of aluminum in component (B) to titanium in component (A) is from 5 to 1000, preferably from 100 to 800, and the molar ratio of silica in component (C) to titanium in component (A) is from 2 to 100, preferably from 8 to 32.

Components (A), (B) and (C) of the catalyst of the invention in the polymerization process can be used directly or after prior complexation.

The catalyst of the invention can be used in the homopolymerization of propylene or the copolymerization of propylene with other α-olefins such as ethylene, 1-butylene, 4-methyl-1-pentene, 1-hexylene, and 1-octylene.

It can be used both in liquid phase polymerization and gas phase polymerization.

Compared to the prior art, the catalyst of the present invention when used in the polymerization of propylene has significant advantages as follows:

1. The shape of the catalyst particles is spherical due to a change in the composition of the solvent system for dissolving magnesium halides, i.e. the ratio of organic epoxy compound to organic phosphorus compound is lower than that of the earlier technology. 2. Catalyst particles of the present invention with large dimensions can be obtained by increasing the amount of inert diluent at a low ratio of organic epoxy compounds to organophosphorus compounds (see Examples 1, 9 and 10 below). Catalyst particle shape in the U.S. patent no. 4,784,983 is good when the particle size is small, but catalyst particles with irregular shapes such as rod-like or date-core-like are formed when the amount of inert diluent is increased at a high ratio of organic epoxy compound to organic phosphoric compound (see Comparative Examples 2-4 below). 3. A catalyst with a larger particle size, made using a magnesium chloride solution with the same composition as shown in Examples U.S. Pat. patent no. 4,784,983 except that the amounts of toluene were increased, was tested in a commercial circular tubular system (provided by Himont Companv, U.S.A., 70,000 tons of polypropylene/year). It can obtain polypropylene with high quality. However, the lines of the system are sometimes clogged and stopped due to the presence of irregularly shaped catalyst particles. The catalyst of this invention was tested in the same system for about 2,000 hours. High quality polypropylene can be obtained. The bulk density of polypropylene is high.

In order that the invention may be more fully understood, the following Examples and Comparative Examples are provided by way of illustration only.

Example 1

1. Production of component (A) solid catalyst:

Anhydrous magnesium chloride (0.05 mol), toluene (95 ml), epoxy chloropropane (EPC) (0.05 mol) and tributyl phosphate (TBP) (0.046 mol) were placed in a reactor that had been completely purged with high purity nitrogen. The temperature is raised to 50°C with stirring, and the mixture is then maintained at that temperature for 2.5 hours, until the solid is completely dissolved. Phthalic anhydride (0.0095 mol) was added to the solution, and the solution was maintained for another 1 hour at 50 °C. The solution is cooled to -25°C. Titanium tetrachloride (56 ml) was then added dropwise over 1 hour. The solution is heated to 80 °C, while the solid product precipitates. Diisobutyl phthalate (0.0056 mol) was added and the mixture was maintained at 80 °C for 1 hour. Part of the solid matter is separated by filtration and washed with toluene (2 x 100 ml). A dark yellow solid precipitate is obtained. The solid was then treated with toluene (60 ml) and titanium tetrachloride (40 ml) for 2 hours at 90 °C. After the filtrate is removed, the processing stage is repeated. The solid was washed with toluene (3 x 100 ml), and then with hexane (2 x 100 ml) to give 5.9 g of a solid containing 1.93 wt % titanium, 19.80 wt % magnesium and 9.3 wt % diisobutyl phthalate.

2. Bulk polymerization in the liquid phase

Triethyl aluminum (0.0025 mol), methyl cyclohexyl dimethoxysilane (0.0001 mol) and solid catalyst component (A) (10 mg) prepared as above were placed in a 5 liter stainless steel autoclave that had been thoroughly purged with propylene. After adding 2.5 1 of propylene and 0.046 mol of hydrogen, the temperature rises to 70 °C. Propylene is polymerized during 2 hours. The amount of polymer obtained was 517 g. The results are shown in Table 1.

Comparative examples 1

1. Production of solid catalyst component

Anhydrous magnesium chloride (0.05 mol), toluene (75 ml), epoxy chloropropane (EPC) (0.1 mol) and tributyl phosphate (TBP) (0.03 mol) were placed in a reactor that was thoroughly purged with highly purified nitrogen. The temperature is raised to 50°C with stirring, and the mixture is then maintained at that temperature for 2.5 hours, until the solids are completely dissolved. Phthalic anhydride (0.008 mol) was added to the solution, and the solution was then kept at 50 °C for another 1 hour. The solution is cooled to - 25°C. Titanium tetrachloride (56 ml) is added dropwise over the course of 1 hour. The solution is heated to 80°C, until the solid product precipitates. Diisobutyl phthalate (0.0056 mol) was added and the mixture was heated at 80 °C for 1 hour. The solid was filtered off and washed with toluene (2 x 100 ml). A dark yellow solid is obtained. The solid was then treated with toluene (60 ml) and titanium tetrachloride (40 ml) for 2 hours at 90 °C. After the filtrate is removed, the processing step is repeated. The solid was washed with toluene (3 x 100 ml), and then with hexane (2 x 100 ml) to give 5.6 g of a solid containing 1.85 wt % titanium, 19.40 wt % magnesium and 8.52 wt % diisobutyl phthalate.

2. Bulk polymerization in the liquid phase

Bulk polymerization was performed in the liquid phase of Example 1 except that component (A) of the solid catalyst of Example 1 was replaced with the solid catalyst component of this comparative example. The results are shown in Table 1.

Examples 2-3

It was done according to Example 1, except that the amount of toluene was replaced by 85 ml and 100 ml. The results are shown in Table 2.

Comparative example 2-4

It was done according to comparative example 1, except that the amount of toluene was replaced by 85 ml and 95 ml. The results are shown in Table 3.

Examples 4-7

It was done according to Example 1 except that the amount of epoxy chloropropane was changed to 0.045 mol, 0.047 mol, 0.057 mol and 0.064 mol. The results are shown in Table 4.

Examples 8-9

It was done according to Example 1 except that the amount of tributyl phosphate was changed to 0.044 mol, 0.05 mol, and 0.055 mol. The results are shown in Table 4.

Example 11

It was done according to Example 1 except that diisobutyl phthalate (0.0056 mol) was changed to dibutyl phthalate (0.0038 mol). The results are shown in Table 5.

In the following tables, R stands for roundness, AR stands for aspect ratio, and BD stands for mass density. R and AR values were determined using a Leica Q 5001 W Image meter.

Claims (10)

1. A catalyst for the polymerization of propylene, characterized in that it consists of the following components: (A) Solid catalyst components made by dissolving magnesium halide in a solvent system consisting of an organic epoxy compound, an organic phosphorus compound and an inert diluent to award a homogeneous solution: the homogeneous solution is mixed with titanium halide to form a mixture: the solid from the mixture is precipitated in the presence of a precipitation aid, the solid is treated with a polycarboxylic acid ester to adsorb the ester to the solid: and the ester adsorbed to the solid is treated with titanium halide and an inert diluent, where the precipitation aid is selected from organic anhydrides, organic acids, ethers and ketones, and where, calculated per mole of magnesium halide, the amount of organic epoxy compound is from 0.2 to 5 moles, and the molar ratio of organic epoxy compound to organic phosphorus compound is from 0.5 to 1.6, (B) An organic aluminum compound having the formula AlRnX^" where each R is independently hydrogen or a hydrocarbyl group having 1-20 carbon atoms, X is halogen, and its number is from 1 to 3: (C) An organosilicon compound having the formula RnSi(OR')4_where R and R' are each independently selected from alkyl, cycloalkyl, aryl and haloalkyl and n is an integer from 0 to 3: where the ratio of component (B) to component (A), measured as the molar ratio of aluminum to titanium, is from 5 to 1000, and the ratio of component (C) to component (A) is, measured as the molar ratio of silicon to titanium, from 2 to 100. 2. Catalyst according to claim 1, characterized in that it is calculated per mole of magnesium halide, the amount of titanium halide added to component (A) is from 0.5 to 150 moles, the amount of precipitation aid is from 0.03 to 1.0 moles, and the amount of polycarboxylic acid ester is from 0.0019 to 0.01 moles. 3. Catalyst according to claim 1, characterized in that, calculated per mole of magnesium halide, the amount of organic epoxy compound is from 0.6 to 2 moles, the molar ratio of organic epoxy compound to organic phosphorus compounds is from 0.9 to 1.4, and the amount of inert diluent is from 1200 to 2400 ml. 4 Catalyst according to claim 1, characterized in that the magnesium halide is selected from magnesium halide, a complex of magnesium halide with water or alcohol, a derivative of magnesium halide in which the halogen atom is replaced by a ludrocarboxyl or halohydrocarboxyl group, and any combination thereof. 5. Catalyst according to claim 1, characterized in that the organic epoxy compound is selected from ethylene oxide, propylene oxide, butylene oxide, butadiene oxide, butadiene dioxide, epoxy chloropropane, methylglycidyl ether, diglycidyl ether, tetrahydrofuran, and any combination thereof. 6. Catalyst according to claim 1, characterized in that the organic phosphorus compound is selected from trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, trimethyl phosphite, triethyl phosphite, tributyl phosphite, triphenyl phosphite, and any combination thereof. 7. Catalyst according to claim 1, characterized in that the precipitation aid is selected from acetic anhydride, phthalic anhydride, succinic anhydride, maleic anhydride, pyromellitic dianhydride, acetic acid, propionic acid, butyric acid, acrylic acid, methacrylic acid, acetone, methyl ethyl ketone, benzophenone, dimethyl ether, diethyl ether, dipropyl ether, dibutyl ether, diamyl ether, and any combination thereof. 8. Catalyst according to claim 1, characterized in that the polycarboxylic acid ester is selected from diethyl malonate, dibutyl malonate, diethyl adipate, dibutyl adipate, diethyl sebacate, dibutyl sebacate, di-n-butyl phthalate, di-isobutyl phthalate, di-? isooctyl phthalate, diethyl maleate, di-n-butyl maleate, diethyl naphthalene dicarboxylate, dibutyl naphthalene dicarboxylate, triethyl trimellitate, tributyl trimellitate, triethyl hemellitate, tributyl hemellitate, tetraethyl pyromellitate, tetrabutyl pyromellitate, and any combination thereof. 9. Catalyst according to claim 1, characterized in that the titanium halide is selected from titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, tetrabutoxy titanium, tetraethoxy titanium, chlorotriethoxy titanium, dichlorodiethoxy titanium, trichloroethoxy titanium, and any combination thereof. 10. Process for polymerizing propylene in the presence of a catalyst according to at least one of claims 1-9.