CN111995704B - Propylene polymerization catalyst and preparation method thereof - Google Patents

Abstract

The invention relates to a preparation method of a catalyst for olefin polymerization, which comprises the steps of adopting metal magnesium and halogenated alkane as initial reactants to generate dialkyl magnesium and magnesium chloride, adding fatty alcohol to generate soluble alkoxy magnesium and dissolve magnesium chloride, and then adding carboxylic acid derivatives to generate an internal electron donor in situ. After reaction with titanium tetrachloride, a stable two-phase emulsion is formed by adding a turbulence reducer and an emulsion stabilizer. And the particle size and the specific surface area of the catalyst can be improved by adjusting the types and the dosage of the turbulence reducer and the emulsion stabilizer. The catalyst has good spherical morphology, moderate particle size and narrow distribution, and has relatively proper specific surface area. The catalyst has higher activity when used for propylene polymerization, and the polypropylene product has higher bulk density and less fine powder.

Description

Propylene polymerization catalyst and preparation method thereof

Technical Field

The invention relates to a catalyst for olefin polymerization, in particular to a propylene homopolymerization or copolymerization catalyst and a preparation method thereof, and more particularly relates to a spherical catalyst which is obtained by taking magnesium metal as an initial reactant and adopting a compound emulsification system and can generate an electron donor in situ and a preparation method thereof.

Background

It is known that in the synthesis technology of polypropylene, a titanium/magnesium catalyst system is widely applied to the synthesis process of isotactic polypropylene due to the characteristics of high efficiency, high stereospecificity and the like. In the industrial production of polypropylene, because of the replication effect of the polymerization product on the catalyst, the spherical granular catalyst with proper grain size can synthesize a spherical polypropylene product which is similar to the catalyst in shape and has good fluidity, grain size distribution and bulk density, does not need a granulation process and has high industrial application value. The most common starting reactants for the preparation of spherical polypropylene catalysts are magnesium chloride (CN85100997, US 4111835, US 4399054, CN 94103454, CN1091748A) and dialkylmagnesium (EP1273595B1, US7271119B 2).

Compared with magnesium chloride and dialkyl magnesium, the magnesium metal has the advantages of wide source and low price, and simultaneously avoids the defects of easy moisture absorption of magnesium chloride and high price, high cost and easy reaction and deterioration of dialkyl magnesium, thereby being an ideal initial reactant for preparing the spherical polypropylene catalyst.

The methods for preparing spherical polypropylene catalysts by using metal magnesium as an initial reactant can be roughly classified into two main types. One class is, for example, j.organomet.chem.,1975,91, 1; US 4127502; in US4547477, magnesium metal is reacted with alkyl halide in aliphatic alkane to produce dialkyl magnesium and magnesium chloride insoluble matter in a molar ratio of 1:1, and then trialkyl aluminum cosolvent is added to dissolve the dialkyl magnesium to form dialkyl magnesium-trialkyl aluminum complex. After magnesium chloride and unreacted metal magnesium insoluble substances are filtered, the obtained solution can be subjected to a series of chemical reactions to load titanium tetrachloride in a one-step method in the process of preparing the spherical magnesium chloride carrier, so that the spherical polypropylene catalyst is obtained.

Another method is a "two-step process" in which a spherical magnesium dialkoxide support is prepared from magnesium metal and then contacted with titanium tetrachloride to obtain a spherical catalyst. For example, CN200580072712.6 discloses a method in which 1.65g N-chlorosuccinimide, 15g of magnesium metal and 240mL of absolute ethanol are mixed and reacted, and the ethanol reflux is maintained at 78 ℃. After 5min, 15g of magnesium metal and 240mL of anhydrous ethanol were added in 3 portions per 20 min, and stirring reflux was maintained for 2 hours after the addition was completed. Then washed 3 times with 2000mL of n-hexane at 50 ℃ and dried under a stream of nitrogen for 24 hours to obtain the spherical support of diethoxymagnesium. 25g of the carrier was mixed with 150mL of toluene, dispersed, added with toluene-diluted titanium tetrachloride (50mL of toluene +25mL of titanium tetrachloride), heated at a rate of 0.5 ℃/min to 60 ℃ and held for 1 hour. And then washing and drying to obtain the spherical polypropylene catalyst. The patent CN201010208524.1 discloses a similar method, with the difference that in addition to magnesium metal and ethanol, elemental iodine and n-butanol are added to the starting material of the reaction system for preparing spherical diethoxymagnesium carrier. The patent CN201110172225.1 selects metal magnesium, 2-ethylhexanol, magnesium chloride and elementary iodine as initial reactants.

Disclosure of Invention

The invention aims to provide a preparation method of a propylene polymerization catalyst, which takes metal magnesium as an initial reactant to prepare the propylene polymerization spherical catalyst, compared with the one-step method, the method does not need to add a trialkyl aluminum cosolvent, simplifies the steps, avoids introducing other substances, and ensures the process economy and safety; compared with the two-step method, the method avoids generating insoluble alkoxy magnesium carrier with low activity, and improves the catalytic performance. The invention also provides a propylene polymerization catalyst prepared by the method, the propylene polymerization catalyst has the characteristics of adjustable particle size and narrow particle size distribution, can generate an internal electron donor in situ, has simple process, mild preparation conditions and less pollution, and particularly has better sphericity, and the obtained polymer has good particle morphology.

Therefore, the invention provides a preparation method of a propylene polymerization main catalyst, which comprises the following steps:

(1) dispersing metal magnesium in organic hydrocarbon to obtain suspension, adding a halogen simple substance as an initiator, heating a reaction mixture to reflux, and dropwise adding halogenated hydrocarbon into the reaction mixture to continue reaction;

(2) continuously adding organic hydrocarbon into the reaction mixture, fully reacting, filtering to remove insoluble substances, and forming a uniform and transparent solution;

(3) contacting and reacting the uniform and transparent solution with a carboxylic acid derivative to obtain a magnesium-containing composite solution;

(4) mixing the magnesium-containing composite solution with a titanium compound;

(5) adding an emulsion stabilizer and a turbulence reducer into the mixed solution obtained in the step (4) to form a stable liquid-liquid two-phase system,

(6) and (5) heating the mixed system obtained in the step (5) to solidify, and precipitating the catalyst.

According to the method, dialkyl magnesium is obtained through reaction in the step (1), in the prior art, triethyl aluminum is usually added as a cosolvent in the separation process to dissolve the product dialkyl magnesium, the filtered solid is another product magnesium chloride and unreacted metal magnesium, and then the filtrate is subjected to separation, concentration, purification and other treatments, and then is subjected to reaction with alcohol and other steps to obtain the catalyst. However, the method of the invention directly adds the fatty alcohol in the step (2), which can not only dissolve the dialkyl magnesium, but also dissolve the magnesium chloride together, thereby improving the utilization rate of the magnesium. Meanwhile, triethyl aluminum is not required to be added for assisting dissolution, so that the introduction of impurities and operation danger are avoided. In addition, after the fatty alcohol is directly added, the preparation process of the catalyst can be connected, and intermediate links are reduced.

In the step (1), the magnesium metal can be in the form of magnesium strips, magnesium sheets, magnesium strips, magnesium chips, magnesium powder and the like, and when the magnesium metal is used, the magnesium metal in one form can be selected, and the magnesium metal in a mixed form can also be selected.

In the preparation method of the propylene polymerization catalyst, in the step (1), the halogen is preferably iodine.

In the preparation method of the propylene polymerization catalyst, in the step (1), the organic hydrocarbon is preferably aliphatic hydrocarbon with 6-14 carbon atoms or aromatic hydrocarbon with 6-20 carbon atoms, and the aliphatic hydrocarbon is preferably straight-chain or branched alkane or cycloalkane.

In the method for preparing the propylene polymerization catalyst, the aliphatic hydrocarbon is preferably at least one selected from n-hexane, n-heptane, n-octane, isooctane, n-nonane and n-decane; the aromatic hydrocarbon is preferably at least one selected from the group consisting of toluene, xylene, trimethylbenzene and ethylbenzene.

In the preparation method of the propylene polymerization catalyst, in the step (1), the halogenated hydrocarbon is linear chain or branched chain halogenated alkane, halogenated cyclane or halogenated aromatic hydrocarbon with the carbon atom number of preferably 2-8.

In the method for preparing the propylene polymerization catalyst, the halogenated hydrocarbon is preferably one selected from 1-chloroethane, 1-chloropropane, 1-chlorobutane, 2-chlorobutane, 1-chlorohexane and chlorobenzene.

In the preparation method of the propylene polymerization catalyst, in the step (2), the organic hydrocarbon is a straight-chain or branched-chain alkyl alcohol with 1-10 carbon atoms, a naphthenic alcohol, an aromatic alcohol with 6-20 carbon atoms or an alkyl-substituted aromatic alcohol, and the organic hydrocarbon is a halogenated hydrocarbon obtained by substituting a halogen for a hydrogen atom on a carbon chain.

In the method for preparing the propylene polymerization catalyst according to the present invention, the aliphatic alcohol compound is preferably at least one selected from the group consisting of methanol, ethanol, propanol, isopropanol, butanol, pentanol, hexanol, 2-methylpentanol, 2-ethylbutanol, heptanol, 2-ethylhexanol, octanol, and decanol.

In the method for preparing the propylene polymerization catalyst according to the present invention, in the step (3), the carboxylic acid derivative is preferably an acid chloride or an acid anhydride having an aromatic group.

In the preparation method of the propylene polymerization catalyst, the carboxylic acid derivative is preferably selected from one of benzoyl chloride, phthaloyl chloride, terephthaloyl chloride, trimesoyl chloride, benzoic anhydride and phthalic anhydride.

In the preparation method of the propylene polymerization catalyst of the present invention, in the step (4), the general formula of the titanium compound is preferably Ti (OR) _a X _b (general formula I), wherein R is C ₁ ～C ₁₀ X is halogen, a is 0, 1, 2 or 3, b is an integer from 1 to 4, and a + b is 3 or 4.

In the method for preparing the propylene polymerization catalyst of the present invention, the titanium compound is preferably at least one selected from the group consisting of titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, tetrabutoxytitanium, tetraethoxytitanium, chlorotriethoxytitanium, dichlorodiethoxytitanium, and trichloromonoethoxytitanium. The titanium compound should be a liquid compound that is completely soluble in the non-polar solvent at the application temperature, preferably titanium tetrachloride.

The preparation method of the propylene polymerization catalyst of the present invention is preferably that the ratio of the components in the preparation process is as follows, wherein each mole of magnesium is: 5 to 50.0 mol of organic hydrocarbon, 0.3 to 3.0 mol of halogenated hydrocarbon, 0.1 to 10.0 mol of aliphatic alcohol compound, 0.05 to 1.0mol of carboxylic acid derivative, and 1.0 to 15.0 mol of titanium compound; the total mass of the organic hydrocarbon, the fatty alcohol compound and the titanium compound is taken as the reference, and the adding amount of the turbulence reducer and the emulsion stabilizer is 10-1000 ppm.

The preparation method of the propylene polymerization catalyst of the present invention is further preferred, wherein the ratio of the components in the preparation process is as follows per mole of magnesium: 15 moles of organic hydrocarbon, 1.0 mole of halogenated hydrocarbon, 2.5 moles of aliphatic alcohol compound, 0.4 mole of carboxylic acid derivative and 8.0 moles of titanium compound; the amounts of the turbulence reducer and the emulsion stabilizer added were 50ppm based on the total mass of the organic hydrocarbon, the aliphatic alcohol compound and the titanium compound.

In the preparation method of the propylene polymerization catalyst, preferably, in the step (1), the reaction temperature is 50-130 ℃; in the step (2), the reaction temperature is 0-30 ℃; in the step (3), the reaction temperature is 40-80 ℃; in the steps (4) and (5), the temperature is-40 ℃; in the step (6), the heating rate during heating and curing is 0.1-2.0 ℃/min, and the heating range is-35-120 ℃.

In the preparation method of the propylene polymerization catalyst, preferably, in the step (1), the reaction temperature is 100 ℃; in the step (2), the reaction temperature is 5-10 ℃; in the step (3), the reaction temperature is 50-70 ℃; in the steps (4) and (5), the temperature is-10-25 ℃; in the step (6), the heating rate during heating and curing is 0.3 ℃/min, and the heating range is 0-90 ℃.

In the method for preparing the propylene polymerization catalyst of the present invention, in the step (5), the emulsion stabilizer is preferably an anionic surfactant, a cationic surfactant, a zwitterionic surfactant or a nonionic surfactant.

In the method for preparing the propylene polymerization catalyst according to the present invention, the nonionic surfactant is preferably at least one selected from the group consisting of sorbitan fatty acid esters, polyoxyethylene ethers, polyoxyethylene amines, polyoxyethylene amides, polymethacrylic acid esters, and polypropylene glycols.

The preparation method of the propylene polymerization catalyst, provided by the invention, is characterized in that the turbulence reducer is preferably selected from at least one of polyoctene, polynonane, polydecene and polydodecene.

The formed catalyst particles can be subjected to conventional washing, drying and other steps to obtain the solid powder catalyst in a flowing state. Optionally, the catalyst particles may also be treated one or more times in order to adjust the titanium content of the catalyst.

The invention also provides a propylene polymerization catalyst, which comprises the following components:

(1) the propylene polymerization main catalyst prepared by the method;

(2) an alkylaluminum compound of the formula AlR ¹ _n X _3－n (general formula II) wherein R ¹ Are identical or different C ₁ ～C ₂₀ Is a linear, branched or cyclic alkyl group, X is halogen, n ═ 1, 2 or 3;

(3) an external electron donor compound having the general formula R ² _n Si(OR ^3` ) _4-n (general formula III) wherein n is 0. ltoreq. n.ltoreq.3, R ² And R ³ The same or different, respectively, are alkyl, cycloalkyl, aryl, haloalkyl, halogen or hydrogen atoms;

wherein, the ratio of the main catalyst for propylene polymerization, the alkyl aluminum compound and the external electron donor compound is as follows: aluminum: the molar ratio between silicon is 1: 5-1000: 0 to 500.

The propylene polymerization catalyst of the present invention, wherein the alkyl aluminum compound is preferably selected from triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, alkylaluminum chloride, Al (n-C) ₆ H ₁₃ ) ₃ 、Al(n-C ₈ H ₁₇ ) ₃ 、AlEt ₂ One or two of Cl.

In many cases, especially when the catalyst is used for the preparation of isotactic polypropylene, the use of an external electron donor compound is essential.

Wherein component (2) and optional component (3) can be contacted with the active component either alone or as a mixture of the two components.

The catalysts described above are suitable for the olefin CH ₂ (ii) polymerization of CHR (wherein R is hydrogen or C1-C6 alkyl or aryl) and mixtures containing, if necessary, small amounts of diolefins.

The polymerization of olefins is carried out according to known methods, operating in the liquid phase of a monomer or of a solution of a monomer in an inert solvent, or in the gas phase, or by a combined polymerization process in the gas-liquid phase. The polymerization temperature is generally from 0 ℃ to 150 ℃ and preferably from 60 ℃ to 100 ℃. The polymerization pressure is normal pressure or higher.

It is worth pointing out that in the catalyst preparation process of the invention, the magnesium metal is used as the initial reactant, and the prepared catalyst has good sphericity, proper size, uniform particle size distribution and simple and mild process conditions. Meanwhile, the consumption of titanium tetrachloride is low, which is beneficial to reducing the pollution to the environment. The catalyst is suitable for slurry polymerization, bulk-gas phase combination and gas phase polymerization processes.

Drawings

FIG. 1 is a photograph characterizing the morphology of the catalyst prepared in example 1;

figure 2 is a photograph characterizing the morphology of the catalyst prepared from example 2.

Detailed Description

The following examples illustrate the invention in detail: the present example is carried out on the premise of the technical scheme of the present invention, and detailed embodiments and processes are given, but the scope of the present invention is not limited to the following examples, and the experimental methods without specific conditions noted in the following examples are generally performed according to conventional conditions.

Example 1

1. Catalyst synthesis: in the presence of high purity N ₂ 17.67g (0.27mol) of 100-mesh magnesium powder and 0.3L of high-purity n-heptane are added into a fully replaced reactor, 0.2g of elemental iodine is added into the system as an initiator, the reaction is started after mixing, the reaction time is 30min, then the reaction mixture is heated to reflux, and 1-chlorobutane is added into the solution dropwise. The total amount of 1-chlorobutane added dropwise was 55.4g (0.598mol), and the temperature of the reaction system was maintained at 97.8 to 99.1 ℃ during the addition. After completion of the reaction, the reaction mixture was cooled to room temperature, and 106.2mL (0.675mol) of isooctanol was slowly added thereto while maintaining the temperature at about 5 ℃. Then, insoluble matter was removed by filtration.

74mL of the clear solution from which insoluble matter was removed was taken, and 2.9mL of phthaloyl chloride (0.02mol) was added thereto to give a pale yellow magnesium-containing complex solution.

In the presence of high purity N ₂ A fully replaced five-neck glass bottle was charged with 44mL of titanium tetrachloride and 40mL of toluene and mixed well. Slowly adding the magnesium-containing composite solution into the titanium tetrachloride/toluene mixed solution, keeping the stirring speed at 200 r/min, and reacting at 25 ℃ for 10min to form a dark red solution. 4mL of a turbulence reducer T803B (a poly-long-chain alpha-olefin diesel pour point depressant) and 4mL of an emulsion stabilizer polymethyl methacrylate were sequentially added to the deep red solution, and then the temperature was raised to 90 ℃ at a rate of 0.3 ℃/min. After filtration, the solid catalyst is obtained by washing the solid catalyst for 2 times respectively with toluene, n-decane and n-hexane and drying the solid catalyst in vacuum. The catalyst morphology is shown in FIG. 1, and the particle size distribution is shown in Table 1.

2. Polymerization of propylene: stainless steel kettle N with volume of 0.2 liter ₂ After the completion of the substitution, 20 mg of the above solid catalyst, 2.0mmol of triethylaluminum and 0.1mmol of CHMMS0.1mmol were added, and 50mL of n-hexane was added as a solvent, and the mixture was heated to 70 ℃ and polymerized at 70 ℃ for 0.5 hour. The polymerization results are shown in Table 2, and the polypropylene product screening results are shown in Table 3.

Example 2

1. Catalyst synthesis: example 1 was repeated except that 1-chlorohexane was used as the halogenated alkane instead of 1-chlorobutane. The catalyst particle size distribution is shown in table 1.

2. Polymerization: the polymerization results are shown in Table 2 and the polypropylene product sieving results are shown in Table 3, as in example 1.

Example 3

1. Catalyst synthesis: example 1 was followed except that chlorobenzene was used instead of 1-chlorobutane as the haloalkane. The catalyst particle size distribution is shown in table 1.

2. Polymerization: the polymerization results are shown in Table 2 and the polypropylene product sieving results are shown in Table 3, as in example 1.

Example 4

1. Catalyst synthesis: the same procedure as in example 1 was repeated, except that n-octanol was used instead of isooctanol. The catalyst particle size distribution is shown in table 1.

2. Polymerization: the polymerization results are shown in Table 2 and the polypropylene product sieving results are shown in Table 3, as in example 1.

Example 5

1. Catalyst synthesis: the same procedure as in example 1 was repeated, except that the amount of phthaloyl chloride used was changed to 1.45mL (0.01 mol). The catalyst particle size distribution is shown in table 1.

2. Polymerization: the polymerization results are shown in Table 2 and the polypropylene product sieving results are shown in Table 3, as in example 1.

Example 6

1. Catalyst synthesis: the same procedure as in example 1 was repeated, except that the amount of titanium tetrachloride used was changed to 88 mL. The catalyst particle size distribution is shown in table 1.

2. Polymerization: the polymerization results are shown in Table 2 and the polypropylene product sieving results are shown in Table 3, as in example 1.

Example 7

1. Catalyst synthesis: example 1 was followed except that cetyltrimethylammonium bromide was used as the emulsifier instead of polymethyl methacrylate. The catalyst particle size distribution is shown in table 1.

2. Polymerization: the polymerization results are shown in Table 2 and the polypropylene product sieving results are shown in Table 3, as in example 1.

Example 8

1. Catalyst synthesis: the same procedure as in example 1 was repeated except that the amount of the polymethylmethacrylate to be used was changed to 20 mL. The catalyst particle size distribution is shown in table 1.

2. Polymerization: the polymerization results are shown in Table 2 and the polypropylene product sieving results are shown in Table 3, as in example 1.

Example 9

1. Catalyst synthesis: example 1 was followed except that dodecene was used as the turbulence reducing agent in place of T803B. The catalyst particle size distribution is shown in table 1.

2. Polymerization of propylene: the polymerization results are shown in Table 2 and the polypropylene product sieving results are shown in Table 3, as in example 1.

Example 10

1. Catalyst synthesis: the same procedure as in example 1 was repeated except that the temperature increase rate was changed to 0.1 ℃ per minute. The catalyst particle size distribution is shown in table 1.

2. Polymerization: the polymerization results are shown in Table 2 and the polypropylene product sieving results are shown in Table 3, as in example 1.

Comparative example 1

1. Catalyst synthesis: in the presence of high purity N ₂ 17.3mL (0.11mol) of isooctanol were added to a fully replaced three-necked glass bottle, and 50mL of a dibutylmagnesium solution (heptane as a solvent, at a concentration of 1.0mol/L) was slowly added to the isooctanol while maintaining the temperature at about 5 ℃. After the dropwise addition, the temperature is raised to 60 ℃ and the reaction is carried out for 30 min. To the above solution were added 2.9mL of phthaloyl chloride (0.02mol) and 7mL of n-butyl chloride (0.11mol) in this order at 60 ℃ to obtain a pale yellow magnesium-containing complex solution.

In the presence of high purity N ₂ A fully replaced five-neck glass bottle was charged with 44mL of titanium tetrachloride and 40mL of toluene and mixed well. Slowly adding the magnesium-containing composite solution into the titanium tetrachloride/toluene mixed solution, keeping the stirring speed at 200 r/min, and reacting at 25 ℃ for 10min to form a dark red solution. To the dark red solution was added 4mL of T803B and 4mL of polymethyl methacrylate, and the temperature was slowly raised to 90 ℃. After filtration, the solid catalyst is obtained by washing the solid catalyst for 2 times respectively with toluene, n-decane and n-hexane and drying the solid catalyst in vacuum. The catalyst particle size distribution is shown in table 1.

2. Polymerization of propylene: the polymerization results are shown in Table 2 and the polypropylene product sieving results are shown in Table 3, as in example 1.

Comparative example 2

1. Synthesizing a catalyst: in the presence of high purity N ₂ 50mL of n-decane and 4.75 g of anhydrous magnesium chloride were added to the fully substituted three-necked glass bottle, and the mixture was dispersed with stirring to obtain a suspension. Raising the temperature to 130 ℃, preserving the temperature for 30min, then slowly adding 19.5mL (0.125mol) of isooctanol into the mixture, and continuing the reaction for 2 hours to obtain a magnesium compound solution.

In the presence of high purity N ₂ 44mL of titanium tetrachloride and 40mL of toluene were added to the fully replaced five-neck glass bottle and mixed well. Slowly adding the magnesium-containing composite solution into the titanium tetrachloride/toluene mixed solution, keeping the stirring speed at 200 r/min, and reacting at 25 ℃ for 10min to form a dark red solution. To the above dark red solution was added 4mLT803B and 4mL of polymethyl methacrylate, followed by slowly raising the temperature to 90 ℃. After filtration, the solid catalyst is obtained by washing the solid catalyst for 2 times respectively with toluene, n-decane and n-hexane and drying the solid catalyst in vacuum. The catalyst particle size distribution is shown in table 1.

2. Polymerization: the polymerization results are shown in Table 2 and the polypropylene product sieving results are shown in Table 3, as in example 1.

Comparative example 3

1. Synthesizing a catalyst: prepared according to example 1 of patent CN 201010208524.1. The catalyst particle size distribution is shown in table 1.

2. Polymerization: the polymerization results are shown in Table 2 and the polypropylene product sieving results are shown in Table 3, as in example 1.

Comparative example 4

1. Synthesizing a catalyst: prepared according to example 1 of patent CN 200780052712.6. The catalyst particle size distribution is shown in table 1.

2. Polymerization: the polymerization results are shown in Table 2 and the polypropylene product sieving results are shown in Table 3, as in example 1.

TABLE 1 results of particle size distribution of catalyst

As can be seen from the data in Table 1, the propylene polymerization catalyst prepared by the method of the present invention has the characteristics of adjustable particle size and narrow particle size distribution, and as can be seen from FIGS. 1 and 2, the polymer obtained by the catalyst has good particle morphology.

TABLE 2 polymerization results

As can be seen from the data in Table 2, the propylene polymerization catalyst prepared by the method of the present invention has a higher polymerization yield.

TABLE 3 screening results of Polymer powders

Examples	Less than 20 mesh	20 to 40 mesh	40-60 mesh	60 to 80 mesh	80 to 100 mesh	100 to 160 mesh
							Example 1	6.1	61.6	12.3	9.2	5.4	0.6
Example 2	14.6	59.3	12.6	7.4	2.8	1.2
							Example 3	21.6	57.6	10.5	4.0	2.9	2.7
Example 4	18.1	56.4	13.3	5.8	3.0	2.4
							Example 5	7.5	64.7	12.6	10.0	3.1	1.5
Example 6	11.1	56.9	14.7	10.3	5.2	1.8
							Example 7	13.6	63.5	13.3	4.8	1.9	1.6
Example 8	16.8	55.8	11.1	9.2	4.7	1.4
							Example 9	9.6	60.6	10.8	12.9	4.1	2.0
Example 10	18.9	52.0	17.5	4.6	4.7	2.3
							Comparative example 1	25.2	51.8	12.6	5.2	2.9	1.4
Comparative example 2	8.9	55.0	15.6	6.6	6.1	3.7
							Comparative example 3	2.5	5.1	80.7	7.6	2.3	1.9
Comparative example 4	0.9	1.1	87.2	8.6	1.1	1.0

The present invention is capable of other embodiments, and various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (21)

1. The preparation method of the propylene polymerization main catalyst is characterized by comprising the following steps:

(1) dispersing metal magnesium in organic hydrocarbon to obtain suspension, adding a halogen simple substance as an initiator, heating a reaction mixture to reflux, and dropwise adding halogenated hydrocarbon into the reaction mixture to continue reaction;

(2) continuously adding fatty alcohol compounds into the reaction mixture, fully reacting, filtering to remove insoluble substances, and forming a uniform and transparent solution;

(3) contacting and reacting the uniform and transparent solution with a carboxylic acid derivative to obtain a magnesium-containing composite solution;

(4) mixing the magnesium-containing composite solution with a titanium compound;

(5) adding an emulsion stabilizer and a turbulence reducer into the mixed solution obtained in the step (4) to form a stable liquid-liquid two-phase system,

(6) heating and curing the mixed system obtained in the step (5) to precipitate a catalyst;

wherein in the step (2), the fatty alcohol compound is at least one of a linear or branched alkyl alcohol having 1 to 10 carbon atoms and a cycloalkanol.

2. The method according to claim 1, wherein in the step (1), the halogen is elemental iodine.

3. The method according to claim 1, wherein in the step (1), the organic hydrocarbon is an aliphatic hydrocarbon having 6 to 14 carbon atoms or an aromatic hydrocarbon having 6 to 20 carbon atoms, and the aliphatic hydrocarbon is a linear or branched alkane or cycloalkane.

4. The method for preparing a propylene polymerization procatalyst according to claim 3, wherein the aliphatic hydrocarbon is at least one selected from the group consisting of n-hexane, n-heptane, n-octane, isooctane, n-nonane, and n-decane; the aromatic hydrocarbon is at least one selected from toluene, xylene, trimethylbenzene and ethylbenzene.

5. The method for preparing a main catalyst for propylene polymerization according to claim 1, wherein in the step (1), the halogenated hydrocarbon is a linear or branched halogenated alkane, halogenated cycloalkane, or halogenated aromatic hydrocarbon having 2 to 8 carbon atoms.

6. The method for preparing a main catalyst for propylene polymerization according to claim 5, wherein the halogenated hydrocarbon is selected from one of 1-chloroethane, 1-chloropropane, 1-chlorobutane, 2-chlorobutane, 1-chlorohexane and chlorobenzene.

7. The method of claim 1, wherein the aliphatic alcohol compound is at least one selected from the group consisting of methanol, ethanol, propanol, isopropanol, butanol, pentanol, hexanol, 2-methylpentanol, 2-ethylbutanol, heptanol, 2-ethylhexanol, octanol, and decanol.

8. The method according to claim 1, wherein in the step (3), the carboxylic acid derivative is an acid chloride or an acid anhydride having an aromatic group.

9. The method of claim 8, wherein the carboxylic acid derivative is selected from the group consisting of benzoyl chloride, phthaloyl chloride, terephthaloyl chloride, trimesoyl chloride, benzoic anhydride, and phthalic anhydride.

10. The method of claim 1, wherein the titanium compound of the formula Ti (OR) in the step (4) is Ti (OR) _a X _b (general formula I), wherein R is C ₁ ～C ₁₀ X is halogen, a is 0, 1, 2 or 3, b is an integer from 1 to 4, a + b =3 or 4.

11. The method of claim 10, wherein the titanium compound is at least one selected from the group consisting of titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, tetrabutoxytitanium, tetraethoxytitanium, chlorotriethoxytitanium, dichlorodiethoxytitanium, and trichloromonoethoxytitanium.

12. The method for preparing a propylene polymerization procatalyst according to claim 1, wherein the ratio of the components in the preparation process is, per mole of magnesium: 5 to 50.0 moles of an organic hydrocarbon, 0.3 to 3.0 moles of a halogenated hydrocarbon, 0.1 to 10.0 moles of a fatty alcohol compound, 0.05 to 1.0 mole of a carboxylic acid derivative, and 1.0 to 15.0 moles of a titanium compound; the total mass of the organic hydrocarbon, the fatty alcohol compound and the titanium compound is taken as the reference, and the adding amount of the turbulence reducer and the emulsion stabilizer is 10-1000 ppm.

13. The method for preparing a propylene polymerization procatalyst according to claim 12, wherein the ratio of the components in the method is such that per mole of magnesium: 15 moles of organic hydrocarbon, 1.0 mole of halogenated hydrocarbon, 2.5 moles of aliphatic alcohol compound, 0.4 mole of carboxylic acid derivative and 8.0 moles of titanium compound; the amounts of the turbulence reducer and the emulsion stabilizer added were 50ppm, based on the total mass of the organic hydrocarbon, the fatty alcohol compound and the titanium compound.

14. The method for preparing the propylene polymerization procatalyst according to claim 1, wherein the reaction temperature in step (1) is from 50 ℃ to 130 ℃; in the step (2), the reaction temperature is 0-30 ℃; in the step (3), the reaction temperature is 40-80 ℃; in the steps (4) and (5), the temperature is-40 ℃; in the step (6), the heating rate during heating and curing is 0.1-2.0 ℃/min.

15. The method for preparing a propylene polymerization procatalyst according to claim 14, wherein the reaction temperature in step (1) is 100 ℃; in the step (2), the reaction temperature is 5-10 ℃; in the step (3), the reaction temperature is 50-70 ℃; in the steps (4) and (5), the temperature is-10-25 ℃; in the step (6), the heating rate during heating and curing is 0.3 ℃/min.

16. The method for preparing a propylene polymerization procatalyst according to claim 1, wherein in step (5), the emulsion stabilizer is an anionic surfactant, a cationic surfactant, a zwitterionic surfactant or a nonionic surfactant.

17. The method of claim 16, wherein the non-ionic surfactant is at least one selected from the group consisting of sorbitan fatty acid ester, polyoxyethylene ether, polyoxyethylene amine, and polypropylene glycol.

18. The method of claim 1, wherein the turbulence reducer is at least one member selected from the group consisting of polyoctene, polynonane, polydecene, and polydodecene.

19. A propylene polymerization catalyst, characterized by comprising the following components:

(1) a propylene polymerization procatalyst prepared by the process of any of claims 1-18;

(2) an alkylaluminum compound of the formula AlR ¹ _n X _3－n (general formula II) wherein R ¹ Are identical or different C ₁ ～C ₂₀ X is halogen, n =1, 2 or 3;

(3) an optional external electron donor compound of the general formula R ² _n Si(OR ^{3`</sup> ) <sub>4-n</sub> (general formula III) where n is 0. ltoreq. n.ltoreq.3, R <sup>2</sup> And R <sup>3`} Is the same as orDifferent from each other, are respectively an alkyl group, a cycloalkyl group, an aryl group, a haloalkyl group, a halogen atom or a hydrogen atom;

wherein, the ratio of the main catalyst for propylene polymerization, the alkyl aluminum compound and the external electron donor compound is as follows: aluminum: the molar ratio between silicon is 1: 5-1000: 0 to 500.

20. Propylene polymerization catalyst according to claim 19 characterized in that the alkyl aluminum compound is selected from triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, alkylaluminum chloride, Al (n-C) ₆ H ₁₃ ) ₃ 、Al(n-C ₈ H ₁₇ ) ₃ One or two of them.

21. The propylene polymerization catalyst of claim 20 wherein the alkylaluminum chloride is AlEt ₂ Cl。

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