阅读说明：本技术 一种用于乙烯聚合的催化剂组分及其制备方法和应用 (Catalyst component for ethylene polymerization and preparation method and application thereof ) 是由 郭正阳 唐璐 周俊领 刘萃莲 王迎 雷世龙 于 2019-10-28 设计创作，主要内容包括：本发明属于催化剂技术领域,公开了一种用于乙烯聚合的催化剂组分及其制备方法和应用,该制备方法包括：在惰性稀释剂存在下,将镁供体、有机环氧化合物、有机磷化合物和给电子激活剂进行接触反应；然后降温,分步加入钛供体,进行接触反应,得到催化剂组分。利用本发明的制备方法制备的催化剂组分,用于乙烯均聚合或共聚合时活性更高、聚合物粒度分布更为集中,同时简化了催化剂的生产流程,降低了生产成本,具有显著的工业应用价值。(The invention belongs to the technical field of catalysts, and discloses a catalyst component for ethylene polymerization, a preparation method and application thereof, wherein the preparation method comprises the following steps: in the presence of an inert diluent, carrying out contact reaction on a magnesium donor, an organic epoxy compound, an organic phosphorus compound and an electron-donating activator; then cooling, adding the titanium donor step by step, and carrying out contact reaction to obtain the catalyst component. The catalyst component prepared by the preparation method has higher activity and more concentrated polymer particle size distribution when being used for ethylene homopolymerization or copolymerization, simplifies the production flow of the catalyst, reduces the production cost and has obvious industrial application value.)

1. A method for preparing a catalyst component for ethylene polymerization, comprising: in the presence of an inert diluent, carrying out contact reaction on a magnesium donor, an organic epoxy compound, an organic phosphorus compound and an electron-donating activator; and then cooling, adding a titanium donor step by step, and carrying out contact reaction to obtain the catalyst component.

2. The method of claim 1, wherein the step-wise addition of the titanium donor is: firstly, adding a part of the titanium donor until the reaction solution becomes turbid, keeping the temperature for a period of time until the reaction solution becomes clear, and then adding the rest of the titanium donor.

3. The production method according to claim 1, wherein the magnesium donor is at least one of magnesium halide, water or alcohol complex of magnesium halide, and derivative of magnesium halide;

the derivative of the magnesium halide is preferably a magnesium halide derivative in which one halogen atom is substituted with a hydrocarbon group or a halohydrocarbyloxy group;

the magnesium halide is preferably at least one of magnesium chloride, magnesium bromide and magnesium iodide.

4. The method according to claim 1, wherein the titanium donor has a general formula of Ti (OR)_4-aX_aWherein R is C₁-C₁₄X is halogen, a is an integer from 1 to 4;

the titanium donor is preferably at least one of titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, tributoxytitanium chloride, dibutoxytitanium dichloride, butoxytitanium trichloride, triethoxytitanium chloride, diethoxytitanium dichloride and ethoxytitanium trichloride.

5. The production method according to claim 1, wherein the organic epoxy compound is at least one of oxides, internal ethers, and glycidyl ethers of aliphatic olefins, aliphatic diolefins, halogenated aliphatic olefins, or halogenated aliphatic diolefins having 2 to 8 carbon atoms; the organic epoxy compound is preferably at least one of ethylene oxide, propylene oxide, butylene oxide, butadiene dioxide, epichlorohydrin, methyl glycidyl ether and diglycidyl ether;

the organophosphorus compound is at least one of hydrocarbyl orthophosphate, hydrocarbyl phosphite, halogenated hydrocarbyl orthophosphate and halogenated hydrocarbyl phosphite; the organic phosphorus compound is preferably at least one of trimethyl orthophosphate, triethyl orthophosphate, tributyl orthophosphate, triphenyl orthophosphate, trimethyl phosphite, triethyl phosphite, tributyl phosphite and benzyl phosphite.

6. The production method according to claim 1, wherein the electron-donating activator is an organic alcohol and/or an organic ether; the organic alcohol is preferably C₁-C₈Further preferably at least one of methanol, ethanol, propanol, isopropanol, butanol, isobutanol, 2-ethylhexanol and glycerol, and still further preferably at least one of ethanol, butanol, 2-ethylhexanol and glycerol; the organic ether is preferably lower aliphatic ether, and is further preferably at least one of methyl ether, ethyl ether, propyl ether, butyl ether and amyl ether;

the inert diluent is at least one of hexane, heptane, octane, decane, benzene, toluene, xylene and derivatives of the hexane, heptane, octane, decane, benzene, toluene and xylene.

7. The preparation method according to claim 1 or 2, wherein the temperature reduction is carried out to a temperature of-15 ℃ to-35 ℃;

the temperature of the contact reaction before temperature reduction is 50-60 ℃;

the organic epoxy compound is used in an amount of 0.005 to 10mol, preferably 0.02 to 5mol, and more preferably 0.5 to 1mol, relative to 1mol of the magnesium donor; the amount of the organic phosphorus compound is 0.005 to 10mol, preferably 0.01 to 5mol, and more preferably 0.1 to 1 mol; the dosage of the electron-donating activator is 0.1-20mol, preferably 0.5-10mol, and further preferably 1-5 mol; the amount of the titanium donor is 0.1 to 15mol, preferably 0.3 to 8mol, and more preferably 4 to 8 mol.

8. The production method according to claim 2, wherein the previously added titanium donor is 0.3 to 5mol with respect to 1mol of the magnesium donor;

in the contact reaction after temperature reduction: firstly, adding a part of the titanium donor until the reaction solution turns turbid, keeping the temperature at-15 ℃ to-35 ℃ for a period of time until the reaction solution turns clear, then adding the rest of the titanium donor, heating to 60-110 ℃ within 0.5-8h, and reacting at the constant temperature for 0.5-1.5 h.

9. A catalyst component produced by the production method according to any one of claims 1 to 8.

10. Use of the catalyst component according to claim 9 as procatalyst for the homopolymerization or copolymerization of ethylene.

Technical Field

The invention relates to the technical field of catalysts, and particularly relates to a catalyst component for ethylene polymerization and a preparation method and application thereof.

Background

Polyolefin products play an important role in the production and life of people, and the development of the polyolefin industry cannot depart from the progress of catalyst technology. Researches show that magnesium chloride and titanium trichloride have similar molecular structures, the specific surface area of the catalyst can be greatly improved by adopting the magnesium chloride as a carrier, the loading effect of an active titanium compound is better, and the activity of the catalyst is obviously improved, so that researchers carry out extensive researches on a catalyst system containing a titanium/magnesium compound. When the titanium-magnesium system catalyst is applied to ethylene polymerization, the catalyst is required to have higher catalytic activity, and ethylene polymers with centralized particle size distribution and uniform particle size can be prepared. The morphology of the polymer is a replica of the catalyst morphology, and therefore, the key to controlling the particle size and distribution of the polymer is to control the particle size and distribution of the catalyst.

For the dissolution-precipitation type titanium-magnesium system catalyst, the particle size and the particle size distribution of catalyst particles are completely controlled by the recrystallization process of a magnesium carrier component, and the catalyst with uniform particle size distribution is not easy to obtain. Chinese patent No. 98101108.X discloses a catalyst for ethylene polymerization or copolymerization and a preparation method thereof, wherein the catalyst is obtained by dissolving magnesium halide in an organic epoxy compound and an organic phosphorus compound, adding an electron-donating activator to form a uniform solution, and reacting the uniform solution with at least one precipitation assistant, a halide of transition metal titanium and a derivative thereof. The catalyst shows high activity when used for ethylene polymerization, and the obtained polymer has good particle form and high apparent density. However, when the catalyst of the present invention is applied to ethylene polymerization, the particle size distribution of the resulting polymer is not sufficiently concentrated. Chinese patent 200510117428.5 discloses a catalyst component for homopolymerization of ethylene or copolymerization of ethylene and other alpha-olefins and its preparation method. The catalyst component comprises a magnesium compound, at least one titanium compound, at least one organic alcohol compound and at least one compound with the general formula R¹ _xR² _ySi(OR³)_zAn organosilicon compound of the formula¹And R²Each is a hydrocarbon group or a halogen, R³Is a hydrocarbon group, x is 0. ltoreq. x.ltoreq.2, y is 0. ltoreq. y.ltoreq.2, z is 0. ltoreq. z.ltoreq.4, and x + y + z is 4. The catalyst has the advantages of high catalytic activity, good hydrogen regulation sensitivity, narrow polymer particle size distribution and the like, and is very suitable for slurry polymerization process of ethylene and combined polymerization process needing high-activity catalyst. The invention introduces an organosilicon compound component without active hydrogen atoms, represented by tetraethoxysilane, into a catalyst system, and the finally obtained solid titanium catalyst component contains enough silicon compounds, thereby improving the comprehensive performance of the catalyst, and simultaneously, the silicon compounds also play a role of a precipitation aid for promoting the precipitation and forming of catalyst particles. However, the particle shape of the catalyst is still not uniform and regular enough, and the influence on the flowability of the catalyst and polymer powder is large. Meanwhile, in the preparation process of the two catalysts, precipitation assistant substances are required to be introduced, so that the complexity of a reaction system is increased to a certain extent, and the cost is increased.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a preparation method of a catalyst component for ethylene polymerization, so that the prepared catalyst component has higher activity and more concentrated polymer particle size distribution when used for ethylene polymerization.

In order to achieve the above object, a first aspect of the present invention provides a method for preparing a catalyst component for ethylene polymerization, the method comprising: in the presence of an inert diluent, carrying out contact reaction on a magnesium donor, an organic epoxy compound, an organic phosphorus compound and an electron-donating activator; and then cooling, adding a titanium donor step by step, and carrying out contact reaction to obtain the catalyst component.

The second aspect of the present invention provides a catalyst component prepared by the above preparation method.

The third aspect of the present invention provides the use of the above catalyst component as a procatalyst for the homopolymerization or copolymerization of ethylene.

The catalyst component prepared by the preparation method has higher activity and more concentrated polymer particle size distribution when being used for ethylene homopolymerization or copolymerization, simplifies the production flow of the catalyst, reduces the production cost and has obvious industrial application value.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Detailed Description

Preferred embodiments of the present invention will be described in more detail below. While the following describes preferred embodiments of the present invention, it should be understood that the present invention may be embodied in various forms and should not be limited by the embodiments set forth herein.

In order to achieve the above object, a first aspect of the present invention provides a method for preparing a catalyst component for ethylene polymerization, the method comprising: in the presence of an inert diluent, carrying out contact reaction on a magnesium donor, an organic epoxy compound, an organic phosphorus compound and an electron-donating activator; and then cooling, adding a titanium donor step by step, and carrying out contact reaction to obtain the catalyst component.

The inventor researches and discovers that: when the catalyst component disclosed in the Chinese patent No. 98101108.X is used for ethylene polymerization, the problem that the particle size distribution of the prepared polymer is not concentrated enough exists; through analytical research, the inventor provides a novel preparation method of a catalyst component for ethylene polymerization, the method removes a precipitation aid component composed of organic acid anhydride, organic acid, organic ether, organic ketone and other compounds when preparing the catalyst, and adopts a method of adding a titanium donor step by step, so that the target catalyst is successfully prepared, the activity is higher when the catalyst is used for ethylene homopolymerization or copolymerization, the particle size distribution is more concentrated, the production flow of the catalyst is simplified, the production cost is reduced, and the catalyst has obvious industrial application value.

In the present invention, preferably, after the reaction is completed, the solid is washed with an inert diluent after the mother liquor is filtered off, and the solid is dried to obtain the solid titanium catalyst component of the present invention.

According to the invention, preferably, the stepwise addition of the titanium donor is: firstly, adding a part of the titanium donor until the reaction solution becomes turbid, keeping the temperature for a period of time until the reaction solution becomes clear, and then adding the rest of the titanium donor.

According to the present invention, preferably, the magnesium donor is at least one of magnesium halide, water or alcohol complex of magnesium halide and derivative of magnesium halide;

the derivative of the magnesium halide is preferably a magnesium halide derivative in which one halogen atom is substituted with a hydrocarbon group or a halohydrocarbyloxy group;

the magnesium halide is preferably at least one of magnesium chloride, magnesium bromide and magnesium iodide.

According to the invention, preferably, the titanium donor has the general formula Ti (OR)_4-aX_aWherein R is C₁-C₁₄X is halogen, a is an integer from 1 to 4;

the titanium donor is preferably at least one of titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, tributoxytitanium chloride, dibutoxytitanium dichloride, butoxytitanium trichloride, triethoxytitanium chloride, diethoxytitanium dichloride and ethoxytitanium trichloride.

According to the present invention, it is preferable that the organic epoxy compound is at least one of oxides, internal ethers, and glycidyl ethers of aliphatic olefins, aliphatic olefin diolefins, halogenated aliphatic olefins, or halogenated aliphatic olefin diolefins having 2 to 8 carbon atoms; the organic epoxy compound is preferably at least one of ethylene oxide, propylene oxide, butylene oxide, butadiene dioxide, epichlorohydrin, methyl glycidyl ether and diglycidyl ether;

the organophosphorus compound is at least one of hydrocarbyl orthophosphate, hydrocarbyl phosphite, halogenated hydrocarbyl orthophosphate and halogenated hydrocarbyl phosphite; the organic phosphorus compound is preferably at least one of trimethyl orthophosphate, triethyl orthophosphate, tributyl orthophosphate, triphenyl orthophosphate, trimethyl phosphite, triethyl phosphite, tributyl phosphite and benzyl phosphite.

According to the present invention, preferably, the electron-donating activator is an organic alcohol and/or an organic ether; the organic alcohol is preferably C₁-C₈Further preferably at least one of methanol, ethanol, propanol, isopropanol, butanol, isobutanol, 2-ethylhexanol and glycerol, and still further preferably at least one of ethanol, butanol, 2-ethylhexanol and glycerol; the organic ether is preferably lower aliphatic ether, and is further preferably at least one of methyl ether, ethyl ether, propyl ether, butyl ether and amyl ether;

the inert diluent is at least one of hexane, heptane, octane, decane, benzene, toluene, xylene and derivatives of the hexane, heptane, octane, decane, benzene, toluene and xylene.

According to the invention, preferably, the temperature reduction is carried out to-15 ℃ to-35 ℃;

the temperature of the contact reaction before temperature reduction is 50-60 ℃;

the organic epoxy compound is used in an amount of 0.005 to 10mol, preferably 0.02 to 5mol, and more preferably 0.5 to 1mol, relative to 1mol of the magnesium donor; the amount of the organic phosphorus compound is 0.005 to 10mol, preferably 0.01 to 5mol, and more preferably 0.1 to 1 mol; the dosage of the electron-donating activator is 0.1-20mol, preferably 0.5-10mol, and further preferably 1-5 mol; the amount of the titanium donor is 0.1 to 15mol, preferably 0.3 to 8mol, and more preferably 4 to 8 mol.

According to the invention, preferably, the titanium donor is added in an amount of 0.3 to 5mol, relative to 1mol of the magnesium donor;

in the contact reaction after temperature reduction: firstly, adding a part of the titanium donor until the reaction solution turns turbid, keeping the temperature at-15 ℃ to-35 ℃ for a period of time until the reaction solution turns clear, then adding the rest of the titanium donor, heating to 60-110 ℃ within 0.5-8h, and reacting at the constant temperature for 0.5-1.5 h.

The second aspect of the present invention provides a catalyst component prepared by the above preparation method.

The third aspect of the present invention provides the use of the above catalyst component as a procatalyst for the homopolymerization or copolymerization of ethylene.

The catalyst component of the present invention is used as a procatalyst in the polymerization of ethylene and is generally used in combination with an organoaluminum cocatalyst, such as triethylaluminum. The dosage ratio of the main catalyst and the organic aluminum cocatalyst and the co-use process of the invention can be carried out according to the conventional dosage range and the conventional co-use method in the field, and the details are not repeated here.

The invention is further illustrated by the following examples:

example 1

Adding 9.6 g (0.10mol) of anhydrous magnesium chloride, 110 ml of toluene (1.04mol), 6.0 ml of epoxy chloropropane (0.077mol), 7.2 ml of tributyl orthophosphate (0.026mol) and 15.2 ml of ethanol (0.26mol) into a reaction kettle repeatedly replaced by high-purity nitrogen in sequence, reacting for 1.5 hours at the temperature of 55 ℃, cooling to-28 ℃, dropwise adding 7 ml (0.064mol) of titanium tetrachloride into the reaction solution, continuously dropwise adding 73 ml (0.664mol) of titanium tetrachloride after keeping the temperature for 0.5 hour, heating to 90 ℃ within 3.5 hours, and keeping the temperature for 0.5 hour. Filtering to remove mother liquor, washing with toluene for 2 times, washing with hexane for 4 times, and drying the residual solid product to obtain the solid titanium catalyst component.

Example 2

The difference between this example and example 1 is only: 7 ml (0.064mol) of titanium tetrachloride was added dropwise, and after keeping the temperature constant for 1 hour, 73 ml (0.664mol) of titanium tetrachloride was further added dropwise.

Example 3

The difference between this example and example 1 is only: 10 ml (0.091mol) of titanium tetrachloride was added dropwise to the reaction solution, and after keeping the temperature for 1 hour, 70 ml (0.637mol) of titanium tetrachloride was further added dropwise.

Example 4

The difference between this example and example 1 is only: after cooling to-15 ℃ and then adding 7 ml (0.064mol) and 73 ml (0.664mol) of titanium tetrachloride in portions according to the method of example 1.

Example 5

The difference between this example and example 1 is only: after cooling to-35 ℃ and then adding 7 ml (0.064mol) and 73 ml (0.664mol) of titanium tetrachloride in portions according to the method of example 1.

Example 6

The difference between this example and example 1 is only: 15.2 ml of ethanol (0.26mol) added at the initial charge were replaced by 23.8 ml of butanol (0.26 mol).

Example 7

The difference between this example and example 1 is only: 15.2 ml of ethanol (0.26mol) added at the initial charge were replaced by 11.4 ml of ethanol (0.195mol) and 3.8 ml of diethyl ether (0.037 mol).

Comparative example 1

This comparative example differs from example 1 only in that: during initial feeding, 9.6 g (0.10mol) of anhydrous magnesium chloride, 110 ml of toluene (1.04mol), 6.0 ml of epoxy chloropropane (0.077mol), 7.2 ml of tributyl orthophosphate (0.026mol), 15.2 ml of ethanol (0.26mol) and 1.6 g of phthalic anhydride (0.011mol) are added in sequence; the temperature, time and titanium tetrachloride addition process for each of the other process steps were the same as in example 1.

Comparative example 2

The comparative example differs from comparative example 1 only in that: 1.6 g (0.011mol) of phthalic anhydride was replaced by 0.8 g (0.0055mol) of phthalic anhydride.

Comparative example 3

The comparative example differs from comparative example 1 only in that: after the temperature is reduced to-28 ℃, 80 ml (0.728mol) of titanium tetrachloride is directly dripped without adopting a stepwise dripping mode.

Comparative example 4

This comparative example differs from example 1 only in that: after the temperature is reduced to-28 ℃, 80 ml (0.728mol) of titanium tetrachloride is directly dripped without adopting a stepwise dripping mode.

Test example

The catalyst components prepared in the above examples and comparative examples were applied to ethylene polymerization under the following specific polymerization conditions:

ethylene slurry polymerization conditions: blowing out a 2L polymerization kettle by using nitrogen, adding 1L hexane, starting stirring, simultaneously adding 2mL of 1mol/L triethyl aluminum hexane solution and 10mg of catalyst component, starting a polymerization kettle control program, heating to 80 ℃, sequentially adding hydrogen and ethylene to reaction pressure, starting polymerization, stopping introducing ethylene after 2 hours, starting cooling, releasing pressure and discharging.

The amounts of phthalic anhydride used in the respective systems of the above examples and comparative examples, the catalytic activities of the catalyst components obtained, and the particle size distribution and Span values (dimensionless amounts, which represent the relative rates of change of the difference in diameter between the larger particles and the smaller particles and the average diameter) of the polymers obtained when they are used for ethylene polymerization are shown in Table 1, wherein phthalic anhydride represents phthalic anhydride. Phthalic anhydride in the comparative example is a representative of the components of the elution assistant consisting of organic acid anhydride, organic acid, organic ether, organic ketone and the like.

TABLE 1

As can be seen from the data in Table 1, in the preparation process of the catalyst, when the components of the precipitation assistant are removed and the titanium halide is dropwise added step by step, the target catalyst can still be successfully prepared, and when the catalyst is used for ethylene polymerization, the particle size distribution of the obtained polymer is more concentrated and the catalytic activity is obviously improved. Meanwhile, the removal of the components of the precipitation aid can simplify the production process of the catalyst, reduce the production cost and have obvious industrial application value.

Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.