RU2312111C1 - Polypropylene and propylene copolymer production process - Google Patents

Abstract

FIELD: polymer production.

SUBSTANCE: invention describes process of producing propylene-based polymer via polymerization of monomer in hydrocarbon solvent at 20-80°C and excessive pressure 1 to 30 atm in presence of catalyst and hydrogen as polymer molecular mass regulator, said catalyst being a product obtained by preliminary treatment of titanium trichloride and diethylaluminum chloride with propylene carried out at weight ratio Et₂AlCl/TiCl₃ = 1 to 10 determined by density of layer of initial TiCl₃ particles within the following limits: 1-2 at density below 0.46 g/cc, 3-5 at density 0.46-0.50 g/cc, 6-10 density above 0.50 g/cc. When polypropylene is obtained, preliminary treatment of titanium trichloride and diethylaluminum chloride with propylene is carried out to achieve conversion 2.0-3.0 g polymer per 1 g TiCl₃ and, when propylene/ethylene copolymer is obtained, treatment is carried out to achieve conversion 3.0-4.0 g polymer per 1 g TiCl₃. After termination of pretreatment of titanium trichloride and diethylaluminum chloride with propylene and before measuring out pretreatment product into principal polymerization reactor, weight ratio Et₂AlCl/TiCl₃ is adjusted to fall into range 6-10 through additionally dosing calculated quantity of diethylaluminum chloride.

EFFECT: prevented breaking of catalyst particles, preserved high activity and stereospecifity thereof, and increased productivity of process.

2 cl, 2 tbl, 18 ex

Description

The invention relates to a technology for the production of polypropylene and copolymers of propylene with ethylene when using titanium trichloride (TiCl ₃ ) as a catalyst and diethylaluminium chloride (DEAC) as a cocatalyst, and in particular to a method for pretreating a catalyst complex (TiCl ₃ + DEAC) before dosing it in main polymerization reactors.

Polypropylene (PP) is one of the most common large-tonnage polymeric materials used in almost all areas of technology.

The TiCl ₃ catalyst used in the proposed method and which is a solid component of the catalyst complex has high activity and stereospecificity, is characterized by a narrow particle size distribution and high bulk density of the resulting powder.

An essential technological feature of the practical use of the catalyst complex (TiCl ₃ + DEAC) is the need for a special technological stage, including pretreatment with propylene before dosing into industrial polymerization reactors. The practical importance of treating the catalyst complex with propylene is to protect the TiCl ₃ catalyst from crushing its particles under the conditions of basic polymerization and to minimize the formation of finely dispersed PP (the dust fraction is particles with a size of <60 μm). It is known from practical experience that an increased yield of the pulverulent fraction significantly reduces the productivity of the technological process, increasing the time of forced technological downtime associated with the unsatisfactory operation of the equipment at the stages of separation of commercial powder of PP.

In the following known methods for producing PP in the presence of a TiCl ₃ -based catalyst complex and DEAC, including pretreatment of the catalyst complex with propylene, various modifications of TiCl _{3 are used} , which differ in the formulation and preparation method, which determines their activity, stereospecificity, chemical and particle size distribution, texture characteristics particulate matter. Practical verification of the conditions for pre-treating the catalyst complex with propylene declared in the known methods shows that they actually reflect the specificity of the used modification of the TiCl ₃ catalyst and are not universal.

The method (JP, Patent No. 55-5761, class C08F 4/64, publ. 1980) uses titanium trichloride with a low reduced activity (≤ 50 g PP / g _CAT · hour · atm). In this method, pretreatment of the catalyst complex with propylene at a temperature of (10 ÷ 40) ° C for 20 min and a yield of ≤ 0.5 g PP / g _cat gives a positive result according to the authors. The description and examples of this patent do not consider the possibility of using the proposed method for pre-treating the catalyst complex with propylene for more active modifications of titanium trichloride. From the patent and scientific literature it is known that for catalysts with a sufficiently high activity (more than 150 g 1111 / g _KAT · h · atm), especially for highly active industrial titanium-magnesium catalysts, regardless of the texture of the catalyst particles, as a rule, the PP yield at the pretreatment stage propylene is at least 3 g PP / g _cat. Therefore, the considered method (JP, Patent No. 55-5761, class C08F 4/64, publ. 1980) does not seem to be universal, although it is acceptable for catalysts with low reduced activity.

The closest in technical essence to the alleged invention is a method for producing PP (JP, Patent No. 54142291, class C08F 110/06, publ. 1979). This method uses a modification of TiCl ₃ with a reduced activity of ~ 100 g PP / g _CAT · hr · atm. In the main polymerization, polypropylene is obtained by polymerization of propylene in a hydrocarbon solvent at (25 ÷ 80) ° С and (1 ÷ 30) at, in the presence of a reaction product as a catalyst complex of the preliminary treatment of titanium trichloride and diethylaluminium chloride with propylene and using hydrogen as a molecular weight regulator polymer.

According to the prototype method, pretreatment of titanium trichloride and diethylaluminium chloride with propylene before feeding the main polymerization reactor is carried out in two stages:

- at the first stage at (15 ÷ 60) ° С the yield is achieved (1 ÷ 5) g PP / g _cat ;

- the second stage of pretreatment with propylene, which is a continuation of the first, is carried out in the presence of hydrogen (up to 6.5 g of hydrogen per 1 g of TiCl ₃ ) until the yield of (5 ÷ 200) g of PP / g _cat at (40 ÷ 80) ° C.

The features and disadvantages of the prototype method include:

1. The method does not take into account the parameters of the texture of the catalyst particles (porosity, packing density, bulk density, etc.) and does not establish the relationship between the texture parameters and the conditions of pre-treatment with propylene of the catalytic complex.

2. The two-stage process and expensive hardware design of the site of preliminary preparation of the catalyst complex.

3. The value of PP yield during preliminary processing with titanium trichloride and diethylaluminium chloride propylene should be at least 5 g PP / g TiCl ₃ , which requires the equipment to be equipped with a sufficiently efficient heat removal system.

4. High hydrogen content in the second stage of the process.

5. The use of a special catalyst modifier - diethylene glycol dimethyl ether.

A common drawback of these methods, including the prototype, is the lack of information on the relationship of the method for producing polypropylene and any (except for particle size distribution) characteristics of the texture of TiCl ₃ catalyst particles. In the scientific literature there is no justified and generally accepted mechanism for the complex process of crushing catalyst particles associated with the specifics of macrokinetic phenomena. Therefore, empirically found methods of protecting specific catalysts from crushing are not sufficiently effective for other modifications of TiCl ₃ that differ in texture parameters, specific activity, and macrokinetic features.

We note the main parameters (distinguishing features) of the pre-treatment with propylene of the catalyst complex in the above methods for the production of PP, which are analogues of this invention:

- the working volume and design features of the apparatus in which the preliminary processing of the catalyst complex is carried out with propylene;

- concentration and total amount of the catalyst complex in the apparatus;

- the concentration of cocatalyst during processing with propylene;

- the working mass ratio of DEAH and TiCl ₃ in the catalyst complex before dosing to the main polymerization reactors;

- physical conditions of the reaction of pretreating the catalyst complex with propylene and the required specific yield of PP during the preliminary treatment of the catalyst complex (g PP / g TiCl ₃ ).

The authors of the present invention found that these parameters are actually determined not only by the hardware-technological design and performance of the process, but also by the specific activity of the catalyst, the texture (morphological features) of its particles and the degree of purity of the main raw materials (solvent, monomers, hydrogen), determined by the concentration of inhibitory impurities. The significance of the texture parameters of TiCl ₃ catalyst particles increases with an increase in the reduced activity of a particular TiCl ₃ modification.

The possibility of sufficiently long storage of the catalyst complex pretreated with propylene according to the proposed method based on TiCl ₃ and DEAC with a working mass ratio of its components (up to 20) without noticeable changes in its properties allows for joint dosage of the components of the catalyst complex in the main polymerization reactors. The latter simplifies and reduces the cost of hardware and technological design of the unit for preparation and dosage of the catalyst complex.

The well-known difference of any continuous technological process of heterogeneous polymerization, including and upon receipt of polyolefins, with respect to the periodic is the inevitable broadening of the particle size distribution of the obtained polymer powders due to the statistical distribution of catalyst particles by their residence time in the main polymerization reactors. With decreasing contact time, the width of the particle size distribution increases.

The objective of the invention is to eliminate the phenomenon of crushing of catalyst particles and, accordingly, to eliminate the contribution of this phenomenon not only to additional broadening of the particle size distribution, but also, more significantly, to the formation of a finely dispersed (pulverulent) fraction of polymer particles with a size of <60 μm.

From production experience it follows that when the pulverulent fraction exceeds 1 wt.%, Serious problems arise at the stage of polymer powder separation associated with the operation of centrifuges, scrubbers, filters, dryers and other equipment. An increase in the yield of the pulverulent fraction is usually accompanied by a decrease in the bulk density of the marketable powder, which reduces the productivity of the granulating equipment.

On the other hand, we found that under the conditions of a continuous industrial polymerization process (in the absence of crushing of catalyst particles and stationary technological parameters), the fraction of the finely dispersed fraction (<60 μm) increases (2 ÷ 4) times with respect to the fraction of this fraction observed in batch polymerization under similar conditions. Thus, the latter should be considered as a quantitative assessment of the influence of the process continuity factor on the increase in the fraction of the finely divided fraction with respect to the batch process. For example, if in a periodic polymerization the fraction fraction <60 μm was ~ 0.1 wt.%, Then the fraction of this fraction in the PP powder obtained in a continuous process with an average residence time of the catalyst in the reactor (3 ÷ 6) hours will be ~ (0 , 2-0.4) wt.%, Respectively.

The table shows, by comparison, the data on the particle size distribution of PP powders obtained for the same batch of catalyst in batch polymerization and under continuous polymerization conditions with the same specific polymer yield (4500 g _PP / g _CAT ).

Table - Influence of the type of polymerization on the granulometry of PP powders in a batch and continuous process Type of polymerization Granulometric composition, wt.% Sizes, microns 500 420 315 250 150 63 <63 Periodic 0.5 1,0 8.6 73.9 15.6 0.3 0.1 Continuous (without crushing particles) 4.2 11.8 fourteen 62.6 6.3 0.8 0.3 Continuous (with crushing particles) 3.0 10.5 14.8 64.7 7.3 1,6 2.1

These data are of a qualitative nature and only illustrate the effect of the type of polymerization and the contribution of particle crushing on the results of a sieve analysis of PP powders.

The proposed method for the production of PP and copolymers of propylene with ethylene (SPE) in a continuous suspension process is implemented as follows. In the apparatus, the so-called complexing agent, where the catalyst complex is pretreated with propylene, in a nitrogen atmosphere, the components of the reaction medium are loaded in a predetermined amount: a hydrocarbon solvent (heptane or hexane fraction of gasoline), a DEAC solution, a suspension of TiCl ₃ . Download TiCl ₃ in the complexing agent is made from a container containing a known amount of catalyst TiCl ₃ . The completeness of unloading of TiCl ₃ from the container is ensured by washing the container with a solvent stream and is controlled during subsequent weighing of the container after it is unloaded. The amount of solvent required for loading into the complexing agent is determined by calculation and depends on the mass of the catalyst (TiCl ₃ ) in the container and the required concentration of TiCl ₃ before starting the dosage of the propylene-treated catalyst complex in the main polymerization reactors.

A distinctive feature of this method is the use of two variants of the sequence of loading the components of the reaction medium into the complexing agent before the start of the next periodic operation of preliminary processing of the catalyst complex with propylene:

- Option No. 1: loading the required quantities of a hydrocarbon solvent and a DEAC solution (the amount of charged DEAC is determined by the working value of the mass ratio of DEAC and TiCl ₃ ), loading a known amount of TiCl ₃ , the dosage of propylene in an amount determined by the specified mass ratio of propylene and TiCl ₃ under the condition of complete monomer conversion. In this case, the total amount of hydrocarbon solvent in the complexing agent is selected from the condition of formation of a working concentration of TiCl ₃ in the complexing agent.

- Option No. 2: loading a hydrocarbon solvent, the first operation of a partial loading of a DEAC solution, loading TiCl ₃ , the dosage of propylene (provided that it is fully converted before the second loading operation of a DEAC solution starts), the second operation of loading a DEAC solution to its predetermined estimated total amount.

For option No. 2, all conditions noted in option No. 1 and related to the ratio and concentration of components in the resulting catalyst complex remain valid.

The suspension of the catalyst complex (after preliminary treatment with propylene) from the complexing agent is overloaded by pressing nitrogen through a sieve filter into a supply tank. The presence of this operation in an industrial environment is necessary as a preventive measure to remove a small amount of agglomerated catalyst particles from the filtered suspension of the catalyst complex, which stabilizes the operation of metering pumps. The filtered catalyst complex is periodically fed into intermediate consumables equipped with mixers for subsequent continuous dosing of the catalyst complex in the main polymerization reactors.

The problem is solved in that the choice between the indicated options for the sequence of loading components (reagents) into the complexing agent is carried out according to the preliminary measurement of the density of the layer of the initial titanium trichloride in a solvent medium precipitated by centrifugation.

The reagents are loaded according to option No. 1, if the density of the TiCl ₃ layer is ≥0.5 g / cm ³ , and according to option No. 2, if the density of the layer is less than 0.5 g / cm ³ . When reagents are loaded according to option No. 2, preliminary processing of the catalyst complex with propylene is carried out immediately after the first operation of partial loading of DEAC and is completed before the start of the second operation of loading DEAC.

A distinctive feature of the invention in relation to the prototype is to take into account the relationship between the density of the TiCl ₃ layer and the mass ratio DEAC / TiCl ₃ at the stage of dosing propylene to the complexing agent. In this case, the ratio of the mass of the layer to the volume of the layer of the initial TiCl ₃ formed by centrifugation of its suspension in a solvent is taken as the density of the TiCl ₃ layer.

An essential distinguishing feature of the method for producing polypropylene and copolymers of propylene with ethylene according to this invention are the restrictions imposed on the ratio of the mass concentration of DEAC and TiCl ₃ in the solvent medium in the complexing agent before processing the catalyst complex with propylene:

a) the ratio DEAC / TiCl ₃ is selected within the range (1 ÷ 2), if the bulk density of the initial TiCl _{3 is} less than 0.46 g / cm ³ ;

b) the DEAH / TiCl ₃ ratio is selected in the range (3 ÷ 5), if the bulk density of the initial TiCl ₃ is in the range (0.46 ÷ 0.50) g / cm ³ ;

c) the DEAH / TiCl ₃ ratio is selected within the range (6 ÷ 10) if the bulk density of the initial TiCl _{3 is} more than 0.5 g / cm ³ ;

d) before starting the dosage of the complex in the main polymerization reactors, the DEAH / TiCl ₃ ratio is set within (6 ÷ 10).

Therefore, points “a”, “b” and “d” refer to the loading of reagents according to option No. 2, and paragraph “c” refers to the loading of reagents according to option No. 1.

The TiCl ₃ catalyst used in the development of the method according to this invention has a high activity of from 150 to 180 g PP / (g _KAT · h · atm). The concentration of TiCl ₃ in the liquid phase of the complexing agent (before starting the dosage of the catalyst complex in the reactors) can be set from 3 to 10 g / l, depending on the activity of the next batch of TiCl ₃ catalyst, the purity of the raw materials used, and special requirements for the consumption rate for the catalyst. The concentration limits of TiCl ₃ in the complexing agent are not a distinctive parameter of any method of producing PP, since they are largely determined by the hardware design and the current process performance. Under the conditions of a specific process, the optimal concentration of TiCl ₃ in the reactor depends on fluctuations in the specific activity of the catalyst between its next batches (set in preliminary test tests) and random changes in the concentrations of inhibitory impurities in the feed.

In the method according to the invention, propylene gas is uniformly dosed to the complexing agent in an amount of ≥2 g of propylene per 1 g of TiCl ₃ (optimally - (2 ÷ 3) g of PP / g of TiCl ₃ ) in the preparation of homopolypropylene and in an amount of ≥3 g of propylene per 1 g of TiCl ₃ (optimally - (3 ÷ 4) g PP / g TiCl ₃ ) upon receipt of a copolymer of propylene and ethylene. The method according to this invention allows an increase in the yield of PP (at the stage of preliminary processing of the catalyst complex with propylene) above the optimal amounts, however, a further increase in the yield is redundant, since it does not affect the efficiency of protection against fragmentation of TiCl ₃ catalyst particles, but at the same time it does not rationally increase the time of preliminary processing. Dosage rate of propylene is limited, on the one hand, the requirement to comply with isothermal polymerization treatment of the catalytic complex when propylene in the range of (15 ÷ 30) and ^C, on the other, - ensuring complete conversion of propylene charged before dosing of the catalyst complex in the main polymerization reactors. The maximum allowable dosing time of propylene is limited only by the need to comply with the conditions ensuring the continuity of the process (specific to a particular technological process for producing polypropylene), since the process of preliminary processing of the catalyst complex with propylene is periodic.

Upon receipt of special grades of PP with increased homogeneity of the composition according to this invention, hydrogen is additionally loaded into the complexing agent (before the propylene dosing operation) up to 0.01 g of hydrogen per 1 g of TiCl ₃ , and in the course of preliminary processing of the catalyst complex with propylene, the partial pressure of hydrogen in the gas the complexing agent phase is maintained in the range (2 ÷ 10) vol.% of the partial pressure of propylene. Moreover, in the method according to this invention, the presence of hydrogen in the indicated amounts does not affect the efficiency of protecting the catalyst particles from crushing.

The suspension of the catalyst complex resulting from the treatment with propylene, including TiCl ₃ , DEAC, pre-treatment reaction products and the solvent, is filtered and then fed into portions in batches, from which metering pumps are continuously dosed into parallel working polymerization reactors.

For a production line with two reactors operating in parallel, the combined polymer suspension stream from two primary reactors enters a secondary reactor (prepolymerization unit). Material streams continuously enter primary reactors: a catalyst complex, a hydrocarbon solvent, propylene (during homopolymerization), propylene and ethylene (during copolymerization), hydrogen (to control the molecular weight of polymers). The main polymerization process is carried out at a pressure of (1 ÷ 30) atm, a temperature of (20 ÷ 80) ^о С, an average residence time of the catalyst in the reactor (1 ÷ 6) hours at a controlled hydrogen content in the reaction medium.

The polymer suspension from the secondary reactor of the processing line is sent to the decontamination of the components of the catalyst complex with a solution of alcohol in a solvent, water-alkaline washing of the polymer and then to the stage of polymer isolation (pressing, drying, standardization and granulation).

The following examples illustrating the invention at the laboratory (batch polymerization process) and industrial test levels (continuous polymerization process) contain the results for three batches of catalyst that have similar specific activity but differ in the density of the TiCl ₃ layer in the solvent medium:

a) examples (1 ÷ 5) relate to a batch of TiCl ₃ with a layer density of 0.45 g / cm ³ ,

b) examples (6 ÷ 10) relate to a batch of TiCl ₃ with a layer density of 0.48 g / cm ³ ,

c) examples (11 ÷ 15) relate to a batch of TiCl ₃ with a layer density of 0.52 g / cm ³ .

Under the conditions of examples 1, 2, 6, 7, 11, 12, there is no crushing of the catalyst particles, therefore, these examples illustrate the influence of the continuity factor (when comparing the batch and continuous process of obtaining PP) for the three above batches of TiCl ₃ .

In all examples, DEAC is used, characterized by the mass ratio Cl / AL = 1.38, and the stationary concentration of hydrogen in the gas phase of the reactor is maintained during the main polymerization within (1.75–2) vol%.

In examples (1-10), the loading of components and preliminary processing of the catalyst complex with propylene are carried out according to option No. 2 (two operations for loading a DEAC solution), in examples (11 ÷ 15) - according to option No. 1 (one operation for loading a DEAC). In all the examples as the hydrocarbon solvent used heptanoic gasoline fraction with a boiling interval (90-99) ^on C.

Examples No. (1 ÷ 5) illustrate the method according to the invention when using a TiCl ₃ catalyst with a layer density in the medium of a hydrocarbon solvent equal to 0.46 g / cm ³ .

Example 1. In a sealed glass reactor in a nitrogen atmosphere are sequentially loaded:

a) 650 ml of hydrocarbon solvent;

b) 33.5 ml of a DEAC solution with a concentration of 150 g / l (5 g DEAC), which corresponds to the mass ratio DEAC / TiCl ₃ = 1;

c) 50 ml of a suspension of TiCl ₃ containing 5 g of TiCl ₃ .

After thermostating the reactor at ²⁰ ° C under continuous stirring to the reactor uniformly dosed gaseous propylene for four hours in an amount of 12 g. reaction medium temperature in the course of propylene dosage is maintained constant at 20 ^C. After 15 minutes after dosing closure propylene pressure the reactor decreased to 0.01 atm, which corresponds to the complete conversion of propylene and the achieved yield of 2.4 g PP / g TiCl ₃ . Next, 266.5 ml of a DEAC solution with a concentration of 150 g / l (40 g DEAC) is loaded into the reactor. The resulting suspension of the treated catalyst complex, the final volume of which is 1000 ml, is mixed for 30 minutes. From an suspension of the catalyst complex homogenized in a glass reactor (TiCl ₃ concentration - 5 g / L, DEAC / TiCl ₃ mass ratio = 9), an aliquot of a 23 ml suspension is taken out by siphoning, which contains 0.115 g of TiCl ₃ and 1.035 g of DEAC.

Propylene polymerization is carried out in a 2 liter steel reactor. First, an ampoule containing 23 ml of a suspension of the propylene-treated catalyst complex is loaded into the reactor, then 1000 ml of a hydrocarbon solvent is poured into the empty reactor in a stream of propylene. After sealing the reactor during its heating, propylene and hydrogen are fed into it. When stationary conditions are reached in the reactor (temperature - 70 ^о С, pressure - 7.5 ati, hydrogen concentration - 1.9 vol.%), An ampoule with a catalyst complex breaks up inside the reactor, which corresponds to the moment the propylene polymerization begins under continuous stirring. Under these stationary conditions, polymerization is carried out for 5.5 hours with chromatographic control of the stationary concentration of hydrogen in the gas phase of the reactor. After completion of the reaction, the reactor is cooled, excess pressure is released, the resulting suspension of polypropylene is discharged by siphoning. Then, alcohol decomposition of the components of the catalyst complex is carried out sequentially, water-alkaline washing and drying of the polymer under conditions similar to example 2. The polymer yield is 4550 g of PP / g of TiCl _{3. The} isotacticity of the obtained PP powder is 97.4%, the yield of atactic PP is 0, 72% of the yield of isotactic PP, which is normal. The mass fraction of a finely dispersed fraction with a size (60 μm is 0.1 wt.%. The presence of this fraction is due only to the particle size distribution of the initial TiCl ₃ catalyst used in this example, due to the well-known phenomenon of geometric similarity of polymer and catalyst particle sizes. As shown by a special checking that under any variations in the conditions of preliminary processing of the catalyst complex, the yield of the fraction with a particle size of ≤60 μm does not decrease. crushing of TiCl ₃ catalyst particles.

Example 2 illustrates a method for producing PP in an industrial continuous process, wherein the batch of TiCl ₃ and the conditions for pretreatment with propylene of the catalyst complex are similar to Example 1.

Example 2. A continuous process for the polymerization of propylene is carried out in a hydrocarbon solvent (suspension process). All the components of the reaction medium are continuously fed into the main polymerization reactors in a predetermined ratio: a catalyst complex that has undergone preliminary treatment with propylene, a hydrocarbon solvent, propylene, and hydrogen.

The preparation of the catalyst complex is carried out in an apparatus (complexing agent) with a volume of 13.2 m ³ equipped with a heat exchange jacket under continuous mixing. 5.5 m ^{3 of a} hydrocarbon solvent is sequentially loaded into a complexing agent in a nitrogen atmosphere, 0.27 m ³ of a DEAC solution with a concentration of 150 kg / m ³ (40 kg DEAC) is sequentially loaded through a flow meter. After homogenizing the prepared solution, a suspension of titanium trichloride containing 40 kg of TiCl _{3 is} loaded from the container into the complexing agent _, which corresponds to the mass ratio DEAC / TiCl ₃ = 1. Slurry temperature is set equal to 20 ° ^C (due to the regulation of temperature and flow rate of coolant in the jacket complexing agent), and excess nitrogen pressure of 0.2 atm by adjusting the flow of nitrogen.

Pretreatment of propylene complex catalyst (TiCl ₃ + DEAC) charged to the complexing agent is carried out at ²⁰ ° C under continuous dosage of propylene to complexing with a predetermined flow rate. The dosage of propylene is carried out for four hours at a flow rate of 24 kg / hour. The total amount of propylene supplied is 96 kg. At the end of the propylene dosage, the pressure in the apparatus was 0.3 ati, and the pre-treatment with propylene continued for 15 minutes until the dissolved propylene was completely bound, which corresponds to a decrease in pressure in the apparatus to 0.2 ati. The complete conversion of propylene corresponds to a yield of 2.4 g _PP / g _CAT .

After completion of the preliminary treatment of the catalyst complex, 2.16 m ³ of DEAH solution with a concentration of 150 kg / m ³ , which corresponds to 320 kg of DEAH, is additionally introduced into the complexing agent. After that, the total mass of DEAC in the complexing agent was 360 kg, which corresponds to the working mass ratio of DEAC / TiCl ₃ = 9, at which the treated catalyst complex is dosed into the main reactors.

The total suspension volume of the resulting catalyst complex is 8 m ³ , while the concentrations of the components (TiCl ₃ and DEAC) were 5 and 45 g / l, respectively.

The suspension of the treated catalyst complex obtained in the complexing agent is filtered and portioned (up to 2 m ³ ) periodically fed into consumable containers, from which it is continuously dosed into two parallel primary polymerization primary reactors with a flow rate of 150 l / h each.

In each primary reactor under conditions of a stationary technological mode, a hydrocarbon solvent with a flow rate of 4660 kg / h, propylene with a flow rate of 4054 kg / h, a suspension of the treated catalyst complex with a flow rate of 150 l / h and hydrogen, the flow rate of which ensures its concentration in the gas phase, are continuously supplied reactors in the range of (1.75 ÷ 2) vol.%.

The polymerization reaction is carried out at a temperature of 70 ^about C, a pressure of 7.5 MPa and an average residence time of the catalyst complex (contact time) of 5.5 hours. A polymer suspension stream is continuously withdrawn from each reactor, the flow rate of which is equal to the sum of the costs of its constituent components: 4660 kg / h of hydrocarbon solvent, 3270 kg / h of isotactic polypropylene, 750 kg / h of propylene, 30 kg / h of atactic polypropylene, 0.73 kg / hour TiCl ₃ , 6.57 kg / hour DEAC.

The combined stream of polymer suspension from two primary reactors enters a secondary reactor — an additional polymerization reactor, in which an additional copolymerization of the dissolved propylene entering the suspension from the primary reactors takes place at a pressure of 4 atm.

The polymer suspension stream from the secondary reactor is continuously fed to successive technological stages: deactivation of the components of the catalyst complex with a solution of (10-12) wt.% N-butanol, water-alkaline washing of the polymer from the decomposition products of the components of the catalyst complex, centrifugation of the suspension, drying and granulation of the polymer powder.

Under stationary conditions of the main polymerization process, the average yield is 4500 g PP / g TiCl ₃ . Isotacticity of PP powder is 97.7 wt.%, Which corresponds to the norm. The output of atactic PP is 0.7 wt.% Of the yield of commodity isotactic PP, which also corresponds to the norm. The mass fraction of a finely dispersed fraction with a particle size (60 μm is 0.29 wt.%, Which is three times the yield of this fraction established by laboratory periodic polymerization according to Example 1, carried out under similar conditions and when the yield is equal to 4500 g of PP / g TiCl ₃ .

Thus, under the conditions of this example, TiCl ₃ catalyst particles are not crushed both at the stage of preliminary processing of the catalyst complex and at the stage of basic polymerization, and the observed broadening of the particle size distribution of the polymer (and a corresponding increase in the yield of the fraction with a size of ≤60 μm) is only a consequence the influence of the process continuity factor.

Example 3. Polypropylene is obtained in a manner analogous to example 2 with the difference that (before starting the dosage of propylene in the complexing agent for processing the catalyst complex), the complexing agent is sequentially loaded with a hydrocarbon solvent (5.6 m ³ ), 0.54 m ³ of DEAH solution with a concentration of 150 kg / m ³ and 40 kg of TiCl ₃ , which corresponds to the mass ratio DEAC / TiCl ₃ = 2.

The polypropylene yield at the pretreatment stage is 2.4 g of PP / g TiCl ₃ , all the conditions of the pretreatment of the catalyst complex are similar to Example 2. After completion of the pretreatment of the catalyst complex with propylene, 1.86 m ³ of DEAH solution with a concentration of 150 kg / m ³ , which corresponds to 279 kg DEAC. After that, the total mass of DEAC in the complexing agent was 360 kg, which corresponds to the working mass ratio of DEAC / TiCl ₃ = 9, at which the treated catalyst complex is dosed into the main reactors.

The total volume of the suspension in the complexing agent is 8 m ³ , while the concentrations of the components of the catalyst complex (TiCl ₃ and DEAC) are 5 and 45 g / l. Further filtration and dosing of the treated catalyst complex in the main polymerization reactors are similar to example 2.

Under stationary conditions of a continuous process of basic polymerization, the average yield is 4600 g of PP / g TiCl ₃ . Isotacticity of PP powder is 97.5 wt.%, The yield of atactic PP is 0.75% of the yield of commercial isotactic PP, which is the norm. The mass fraction of the fine fraction with a size <60 μm is 0.31 wt.%, Which practically does not differ from its content in example 1.

Thus, under the conditions of this example, the fragmentation of TiCl ₃ catalyst particles also does not occur, and the observed broadening of the particle size distribution of the polymer (and the corresponding increase in the yield of the PP powder fraction with particle size ≤60 μm) is only a consequence of the influence of the process continuity factor.

Example 4. Polypropylene is obtained by a method similar to that described in example 2 with the difference that before starting the dosage of propylene in the complexing agent, the following are sequentially loaded: a hydrocarbon solvent (5.48 m ³ ), 1.12 m ³ of DEAH solution with a concentration of 150 kg / m ³ and 42 kg of TiCl ₃ , which corresponds to the mass ratio DEAC / TiCl ₃ = 4. All conditions for pretreatment of the catalyst complex with propylene are similar to example 2.

The yield of polypropylene after processing the catalyst complex with propylene is 2.5 g of PP / g of TiCl ₃ .

After completion of the preliminary treatment of the catalyst complex with propylene, an additional 1.4 m ³ of DEAH solution with a concentration of 150 kg / m ³ , which corresponds to 210 kg of DEAH, is additionally introduced into the complexing agent. After that, the total mass of DEAC in the complexing agent was 378 kg, which corresponds to the working mass ratio of DEAC / TiCl ₃ = 9, at which the catalyst complex is dosed into the main reactors.

The total suspension volume of the treated catalyst complex is 8 m ³ , while the concentrations of the components of the catalyst complex (TiCl ₃ and DEAC) are 5.25 and 47.25 g / l, respectively. Further filtering and dosing of the catalyst complex in the reactors are similar to example 2.

Under stationary conditions of a continuous process of basic polymerization, the average yield is 4550 g of PP / g of TiCl ₃ . The isotacticity of PP powder is 97.4%, the yield of atactic PP is 0.75% of the yield of commercial isotactic PP, which is the norm. The mass fraction of a finely dispersed fraction with a size of ≤60 μm is 0.82 wt.%, Which exceeds its content (more than 2 times) in comparison with examples 2 and 3.

Thus, under the conditions of this example, partial fragmentation of TiCl ₃ catalyst particles occurs at the stage of preliminary processing of the catalyst complex, which (in addition to the influence of the process continuity factor) makes an additional contribution to the observed broadening of the particle size distribution of the polymer and a corresponding increase in the yield of the fraction with a particle size of ≤60 μm .

Example 5. Polypropylene is obtained by a method similar to that described in example 2, with the difference that before starting the dosage of propylene in the complexing agent, the following are sequentially loaded: a hydrocarbon solvent (5.72 m ³ ), 0.18 m ³ of a DEAC solution with a concentration of 150 kg / m ³ and 38 kg of TiCl ₃ , which corresponds to the mass ratio DEAC / TiCl ₃ = 0.71. All conditions for pretreatment of the catalyst complex with propylene are similar to Example 2. The yield of polypropylene at the stage of pretreatment of the catalyst complex with propylene is 2.5 g of PP / g of TiCl ₃ .

After the preliminary treatment of the catalyst complex with propylene is completed, an additional 2.1 m ³ of DEAC solution with a concentration of 150 kg / m ³ , which corresponds to 315 kg of DEAC, is additionally introduced into the complexing agent. After that, the total mass of DEAC in the complexing agent was 342 kg, which corresponds to the working mass ratio of DEAC / TiCl ₃ = 9, at which the treated catalyst complex is dosed into the main reactors.

The total suspension volume of the treated catalyst complex is 8 m ³ , while the concentrations of the components of the catalyst complex (TiCl ₃ and DEAC) are 4.75 and 42.75 g / l, respectively. Further filtering and dosing of the catalyst complex in the reactors are similar to example 2.

Under stationary conditions of a continuous process of basic polymerization, the average yield is 4400 g of PP / g TiCl ₃ . The isotacticity of PP powder is 97.4%, the yield of atactic PP is 0.75% of the yield of commercial isotactic PP, which is the norm. The mass fraction of the fine fraction of PP powder with a size <60 μm is 0.93 wt.%, Which exceeds its content by almost 3 times in comparison with Example 2.

Thus, under the conditions of this example, there is a broadening of the particle size distribution of the polymer and a corresponding increase in the yield of the PP powder fraction with a particle size of ≤60 μm as compared with Example 2, which is due to the partial fragmentation of TiCl ₃ catalyst particles at the stage of basic polymerization.

Examples 6 to 10 illustrate the method according to the invention when using a TiCl ₃ catalyst with a layer density in the environment of a hydrocarbon solvent equal to 0.48 g / cm ³ .

Example 6. Polypropylene is obtained by a method analogous to example 1, with the difference that before starting the treatment of the catalyst complex with propylene, in a glass reactor are sequentially loaded: 650 ml of a hydrocarbon solvent, 133.5 ml of a DEAC solution with a concentration of 150 g / l (20 g DEAC ) and 50 ml of a suspension of TiCl ₃ containing 5 g of TiCl ₃ (mass ratio DEAC / TiCl ₃ = 4), and after preliminary processing of the catalyst complex with propylene, an additional 167.5 ml of a solution of DEAC with a concentration of 150 g / l (25 g DEAH).

An aliquot of a 25 ml suspension containing 0.125 g of TiCl ₃ and 1.125 g of DEAC is selected from the homogenized suspension of the treated catalyst complex (TiCl ₃ concentration - 5 g / l, DEAC / TiCl ₃ mass ratio = 9). The remaining operations are similar to example 1.

The polymer yield after the main polymerization is 4600 g PP / g TiCl _{3. The} isotacticity of the obtained PP powder is 97.2%, the yield of atactic PP is 0.74 wt.% Of the yield of isotactic PP, which is normal. The mass fraction of finely divided fraction with a size of ≤60 μm is 0.14 wt.%. The observed yield of the finely divided PP fraction is due only to the particle size distribution of the initial catalyst used in this example. Thus, under the conditions of this example, crushing of TiCl ₃ catalyst particles does not occur.

Example 7. Polypropylene is obtained by a method analogous to example 2, with the difference that the beginning of the preliminary processing of the catalyst complex with propylene is preceded by loading into the complexing agent 1.09 m ³ of a DEAC solution with a concentration of 150 kg / m ³ . After homogenization of the prepared solution, a suspension of titanium trichloride containing 41 kg of TiCl _3, which corresponds to the mass ratio DEAC / TiCl ₃ = 4, is loaded from the container into the complexing agent. The complete conversion of propylene (after completion of the propylene dosage) corresponds to a yield of 2.4 g of _PP / g of _CAT . Next, 1.37 m ³ of DEAH solution with a concentration of 150 kg / m ³ , which corresponds to 205 kg DEAH, is additionally introduced into the complexing agent. After that, the treated catalyst complex is dosed into the main reactors (as part of the complex: DEAX / TiCl ₃ mass ratio = 9, TiCl ₃ concentration - 5 g / l, DEAC concentration - 45 g / l).

Under stationary conditions of a continuous process of basic polymerization, the average yield was 4600 g PP / g TiCl ₃ . Isotacticity of PP powder is 97.5 wt.%, The yield of atactic PP is 0.7% of the yield of commercial isotactic PP, which is the norm. The mass fraction of the fine PP fraction with a particle size <60 μm is 0.35 wt.%, Which (taking into account the process continuity factor) corresponds to the yield of the pulverulent fraction established in laboratory periodic polymerization according to Example 6 with the same specific polymer yield.

Thus, under the conditions of this example, TiCl ₃ catalyst particles are not crushed both at the stage of preliminary processing of the catalyst complex and at the stage of basic polymerization, and the observed broadening of the particle size distribution of the polymer (and a corresponding increase in the yield of the fraction with a size of ≤60 μm) is only a consequence the influence of the process continuity factor.

Example 8. Polypropylene is obtained by a method similar to examples 2 and 7, with the difference that the pretreatment of the catalyst complex with propylene is preceded by loading 6 m ^{3 of a} hydrocarbon solvent, 2.0 m ³ of DEAC solution with a concentration of 150 kg / m ³ into the complexing agent. After homogenization of the prepared solution, a suspension of titanium trichloride containing 43 kg of TiCl ₃ , which corresponds to the mass ratio DEAC / TiCl ₃ = 7, is loaded from the container into the complexing agent. The complete conversion of propylene (after completion of the propylene dosage) corresponds to a yield of 2.5 g of _PP / g of _CAT . Then, 0.58 m ³ of DEAH solution with a concentration of 150 kg / m ³ , which corresponds to 87 kg DEAH, is additionally introduced into the complexing agent. The total volume of the suspension of the catalyst complex is 8.6 m ³ . After that, the treated dosage complex catalyst in the main polymerization reactors (consisting in: the weight ratio of DEAC / TiCl ₃ = 9, the concentration of TiCl ₃ - 5 g / l, the concentration of DEAC - 45 g / l).

Under stationary conditions of a continuous process of basic polymerization, the average yield was 4700 g PP / g TiCl ₃ . Isotacticity of PP powder is 97.8 wt.%, The yield of atactic PP is 0.7% of the yield of commodity isotactic PP, which corresponds to the norm. The mass fraction of the fine fraction with a size of ≤60 μm is 0.75 wt.%. Thus, in comparison with example 7, there is an increase of 0.4 wt.% The yield of the PP dust fraction, indicating a corresponding fragmentation of the TiCl ₃ catalyst particles.

Example 9. Polypropylene is obtained by a method similar to examples 2, 7, 8 with the difference that the pretreatment of the catalyst complex with propylene is preceded by loading into the complexing agent the entire amount of DEAX solution with a concentration of 150 kg / m ³ (volume of DEAX solution is 2.64 m ³ ), i.e. loading of reagents into the complexing agent is carried out according to option No. 1. After homogenization of the prepared DEAH solution, a suspension of titanium trichloride containing 44 kg of TiCl ₃ , which corresponds to the mass ratio of DEAH / TiCl ₃ = 9, is loaded from the container into the complexing agent. The complete conversion of propylene (after completion of the propylene dosage) corresponds to a yield of 2.5 g of _PP / g of _CAT . The total volume of the suspension of the catalyst complex is 8.8 m ³ . After that, the treated dosage complex catalyst in the main polymerization reactors (consisting in: the weight ratio of DEAC / TiCl ₃ = 9, the concentration of TiCl ₃ - 5 g / l, the concentration of DEAC - 45 g / l).

Under stationary conditions of a continuous process of basic polymerization, the average yield was 4650 g PP / g TiCl ₃ . The isotacticity of PP powder is 97.7%, the yield of atactic PP is 0.68 wt.% Of the yield of commercial isotactic PP. Mass fraction of a finely dispersed fraction with a size (60 μm is 2.55 wt.%. Thus, in comparison with example 8, there is an additional increase in the yield of PP dust fraction (2.2 wt.% More than in example 7), indicating a large the degree of fragmentation of the particles of the catalyst TiCl ₃ .

Example 10. Polypropylene is obtained by a method analogous to example 2, with the difference that the beginning of the processing of the catalyst complex with propylene is preceded by loading into the complexing agent 0.52 m ³ of a DEAC solution with a concentration of 150 kg / m ³ . After homogenizing the prepared solution, a suspension of titanium trichloride containing 39 kg of TiCl _{3 is} loaded from the container into the complexing agent, which corresponds to the mass ratio DEAC / TiCl ₃ = 2. The complete conversion of propylene (after completion of the propylene dosage) corresponds to a yield of 2.4 g of _PP / g of _CAT . Then, 1.82 m ³ of DEAH solution with a concentration of 150 kg / m ³ , which corresponds to 273 kg of DEAH, is additionally introduced into the complexing agent. The total volume of the suspension of the catalyst complex is 7.8 m ³ . After homogenization, the treated catalyst complex is dosed into the main polymerization reactors (mass ratio DEAC / TiCl ₃ = 9, TiCl ₃ concentration - 5 g / l, DEAC concentration - 45 g / l).

Under stationary conditions of a continuous process of basic polymerization, the average yield was 4550 g PP / g TiCl ₃ . Isotacticity of PP powder is 97.1%, the yield of atactic PP is 0.73 wt.% Of the yield of commercial isotactic PP, which is the norm. Mass fraction of finely dispersed fraction with a particle size (60 μm is 0.95 wt.%.

Thus, in comparison with example 7, in the conditions of this example, there is an additional increase in the yield of PP dust fraction (by 0.65 wt.% More than in example 7), indicating the fragmentation of TiCl ₃ catalyst particles.

In examples 11 ÷ 15, a modification of TiCl _{3 is used} , for which the layer density in the medium of a hydrocarbon solvent is 0.52 g / cm ³ .

Example 11. Polypropylene is obtained by a method analogous to example 1, with the difference that the loading of reagents into the complexing agent is carried out according to option 1 (i.e., loading of a suspension of TiCl _{3 was} preceded by a single loading of the required amount of DEAC solution into a glass reactor). Before starting the preliminary treatment of the catalyst complex with propylene, 650 ml of a hydrocarbon solvent, 300 ml of a DEAC solution with a concentration of 150 g / l (45 g DEAC) and 50 ml of a suspension of TiCl ₃ containing 5 g of TiCl ₃ (mass ratio of DEAC / TiCl are sequentially loaded into a glass reactor) ₃ = 9). After processing the catalyst complex with propylene, the polymer yield was 2.4 g of _PP / g of _CAT .

From an homogenized suspension of the treated catalyst complex (TiCl ₃ concentration - 5 g / L, DEAC concentration - 45 g / L, DEAC / TiCl ₃ mass ratio = 9), an aliquot of a 25 ml suspension containing 0.125 g TiCl ₃ and 1.125 g is selected by siphoning DEAH. The remaining operations are similar to example 1.

The polymer yield is 4750 g PP / g TiCl ₃ . The isotacticity of the obtained PP powder is 97.0%, the yield of atactic PP is 0.77 wt.% Of the yield of isotactic PP, which corresponds to the norm. The mass fraction of the fine fraction with a size of ≤60 μm is 0.08 wt.%. The observed yield of the pulverulent fraction is due only to the particle size distribution of the initial catalyst used in this example. Thus, under the conditions of this example, crushing of TiCl ₃ catalyst particles does not occur.

Example 12. Polypropylene is obtained in a manner analogous to example 9. The loading of reagents into the complexing agent is carried out according to option 1, i.e. loading the suspension of TiCl _{3 was} preceded by a single loading into the apparatus of the required amount of DEAH solution with a concentration of 150 kg / m ³ and a volume of 2.2 m ³ . After homogenization of the prepared DEAH solution, a suspension of titanium trichloride containing 37 kg of TiCl _3, which corresponds to the mass ratio of DEAH / TiCl ₃ = 9, is loaded into the complexing agent from the container. The complete conversion of propylene (after completion of the propylene dosage) corresponds to a yield of 2.6 g _PP / g _CAT . The total volume of the suspension of the complex was 7.4 m ³ . A suspension of the treated catalyst complex (mass ratio DEAH / TiCl ₃ = 9, concentration TiCl ₃ - 5 g / l, concentration DEAH - 45 g / l) is dosed into the main polymerization reactors.

Under stationary conditions of a continuous process of basic polymerization, the average yield was 4800 g of PP / g of TiCl ₃ . Isotacticity of PP powder is 96.9 wt.%, Which corresponds to the norm. The output of atactic PP is 0.73 wt.% Of the yield of marketable isotactic PP powder. The mass fraction of the fine fraction with a particle size of ≤60 μm is 0.21 wt.%.

Thus, in comparison with example 11, the content of the PP dust fraction observed under the conditions of this example is due only to the influence of the continuity factor of the polymerization process.

Example 13. Polypropylene is obtained by a method similar to examples 2, 10, with the difference that the beginning of the preliminary treatment of the catalyst complex with propylene is preceded by loading of 0.28 m ³ of DEAC solution with a concentration of 150 kg / m ³ . After homogenizing the prepared solution, a suspension of titanium trichloride containing 42.5 kg of TiCl ₃ , which corresponds to the mass ratio DEAC / TiCl ₃ = 1, is loaded from the container into the complexing agent. The complete conversion of propylene (after completion of the propylene dosage) corresponds to a yield of 2.5 g of _PP / g of _CAT . Next, 2.27 m ³ of DEAH solution with a concentration of 150 kg / m ³ , which corresponds to 340 kg DEAH, is additionally introduced into the complexing agent. The total volume of the suspension of the catalyst complex is 8.5 m ³ . After that, the treated dosage complex catalyst in the main polymerization reactors (consisting in: the weight ratio of DEAC / TiCl ₃ = 9, the concentration of TiCl ₃ - 5 g / l, the concentration of DEAC - 45 g / l).

Under stationary conditions of a continuous process of basic polymerization, the average yield was 4670 g PP / g TiCl ₃ . Isotacticity of PP powder is 97.3 wt.%. The output of atactic PP is 0.79% of the yield of marketable isotactic PP powder. The mass fraction of finely divided fraction with a size of ≤60 μm is 3.92 wt.%.

Thus, in the conditions of this example (in contrast to examples 11 and 12), there is a significant increase in the yield of the PP dust fraction (by 3.71 wt.% More than in example 12), indicating the fragmentation of TiCl ₃ catalyst particles.

Example 14. Polypropylene is obtained by a method similar to examples 2, 10, with the difference that the beginning of the pretreatment of the catalyst complex with propylene is preceded by the loading of 1.79 m ³ of DEAC solution with a concentration of 150 kg / m ³ . After homogenizing the prepared solution, a suspension of titanium trichloride containing 38.4 kg of TiCl ₃ , which corresponds to the mass ratio DEAC / TiCl ₃ = 7, is loaded from the container into the complexing agent. The complete conversion of propylene (after completion of the propylene dosage) corresponds to a yield of 2.5 g of _PP / g of _CAT . Then, 0.51 m ³ of DEAH solution with a concentration of 150 kg / m ³ , which corresponds to 76.8 kg of DEAH, is additionally introduced into the complexing agent. The total volume of the suspension of the catalyst complex is equal to 7.7 m ³ . After that, the treated dosage complex catalyst in the main polymerization reactors (consisting in: the weight ratio of DEAC / TiCl ₃ = 9, the concentration of TiCl ₃ - 5 g / l, the concentration of DEAC - 45 g / l).

Under stationary conditions of a continuous process of basic polymerization, the average yield was 4700 g PP / g TiCl ₃ . The isotacticity of PP powder is 97.1%. The output of atactic PP is 0.72 wt.% Of the output of commodity isotactic PP. The mass fraction of the fine fraction with a size of ≤60 μm is 0.54 wt.%.

Thus, under the conditions of this example, there is a slight increase in the yield of the PP dust fraction (0.31 wt.% More than in Example 12) and, therefore, the fragmentation of TiCl ₃ catalyst particles is manifested to a small extent.

Example 15. Polypropylene is obtained by a method analogous to example 12. The loading of reagents into the complexing agent is carried out according to option 1, i.e. loading the suspension of TiCl _{3 was} preceded by a single loading into the apparatus of the required amount of solvent (5.3 m ³ ), a DEAC solution with a concentration of 150 kg / m ³ and a volume of 2.95 m ³ (441.6 kg DEAC). After homogenization of the prepared DEAH solution, a suspension of titanium trichloride containing 36.8 kg of TiCl _{3 is} loaded from the container into the complexing agent _, which corresponds to the mass ratio of DEAC / TiCl _{3 =} 12. The complete conversion of propylene (after completion of the propylene dosage) corresponds to a yield of 2.5 g of _PP / g _CAT . The total suspension of the catalyst complex is 8.4 m ³ . The suspension of the treated catalyst complex (in the complex: mass ratio DEAH / TiCl ₃ = 9, concentration TiCl ₃ - 4.4 g / l, concentration DEAH - 52.8 g / l) is dosed into the main polymerization reactors.

Under stationary conditions of the continuous process of basic polymerization, the average yield was 4750 g of PP / g of TiCl _{3. The} isotacticity of PP powder was 97.2%, which is normal. The output of atactic PP is 0.57% of the yield of commodity isotactic PP. The mass fraction of the fine fraction with a size of ≤60 μm is 0.67 wt.%.

Thus, in comparison with example 12, the additional increase in the yield of PP dust fraction observed under the conditions of this example is due not only to the influence of the continuity factor of the polymerization process, but also to the contribution of TiCl ₃ catalyst particles from crushing.

The following example illustrates a method for producing a copolymer of propylene and ethylene in an industrial continuous process. In this example, a batch of TiCl _{3 is used} , similar to example 2.

Example 16. A continuous process for the copolymerization of propylene and ethylene is carried out in a hydrocarbon solvent (suspension process). All components of the reaction medium are continuously fed into the main polymerization reactors in a predetermined ratio: a hydrocarbon solvent, a catalyst complex that has undergone preliminary treatment with propylene, propylene, ethylene and hydrogen.

The preparation of the catalyst complex is carried out under conditions similar to example 2. 5.5 m ^{3 of a} hydrocarbon solvent is sequentially loaded into a complexing agent in a nitrogen atmosphere and through a flow meter 0.25 m ³ of a DEAC solution with a concentration of 150 kg / m ³ . After homogenization of the prepared solution, a suspension of titanium trichloride containing 37 kg of TiCl _3, which corresponds to the mass ratio DEAC / TiCl ₃ = 1, is loaded from the container into the complexing agent.

Slurry temperature is set equal to 20 ° ^C (due to the regulation of temperature and flow rate of coolant in the jacket of complexing) and excess nitrogen pressure of 0.2 atm by adjusting the flow of nitrogen.

Pretreatment of catalytic complex of propylene is carried out at ²⁰ ° C under continuous dosage of propylene to complexing with a predetermined flow rate. The total amount of propylene supplied is 120 kg. The dosage of propylene is carried out for four hours at a flow rate of 30 kg / hour. At the end of the propylene dosage, the pressure in the apparatus was 0.3 ati, and the process of treating the catalyst complex with propylene continued for 15 minutes until the dissolved propylene was completely bound, which corresponds to a decrease in pressure in the apparatus to 0.2 ati. The complete conversion of propylene corresponds to a yield of 3.25 g _PP / g _CAT .

After processing the catalyst complex with propylene, 1.97 m ³ of DEAH solution with a concentration of 150 kg / m ³ , which corresponds to 296 kg of DEAH, is additionally introduced into the complexing agent. After that, the total mass of DEAC was 333 kg, which corresponds to the working value of the mass ratio DEAC / TiCl ₃ = 9, at which the treated catalyst complex is dosed into the main reactors.

The total suspension volume of the resulting catalyst complex is 8 m ³ , while the concentrations of the components of the catalytic system (TiCl ₃ and DEAC) are 4.6 and 41.6 g / l, respectively.

The suspension of the treated catalyst complex obtained in the complexing agent is filtered and portioned (up to 2 m ³ ) periodically fed into consumable containers, from which it is continuously dosed into two parallel primary polymerization primary reactors with a flow rate of 150 l / h each.

In each primary reactor under the conditions of a stationary technological mode, continuously fed: hydrocarbon solvent with a flow rate of 4500 kg / h, propylene with a flow rate of 3650 kg / h, ethylene with a flow rate of 180 kg / h and hydrogen, the flow rate of which provides a concentration of 2 vol.% In the gas phase the reactor. The copolymerization reaction is carried out at a temperature of 60 ° C, a pressure of 7.5 MPa and an average residence time of the catalyst complex (contact time) of 5.5 hours. A suspension stream is continuously discharged from each reactor, the flow rate of which is equal to the sum of the costs of its constituent components: 3750 kg / h of a hydrocarbon solvent, 2500 kg / h of a powdered copolymer of propylene and ethylene, 50 kg / h of a soluble fraction of the copolymer, 605 kg / h of propylene, 15 kg / h ethylene, 0.675 kg / h TiCl ₃ , 6.1 kg / h DEAH.

The combined stream of suspension from two primary reactors enters a secondary reactor, an additional polymer, into which ethylene is additionally fed at a rate of 40 kg / h. In a secondary reactor at a stationary pressure of 3.5–4 atm, the copolymerization results in the depolymerization of dissolved propylene. The subsequent stages of the process are similar to example 2.

Under stationary conditions of the main polymerization process, the average yield of copolymer (SPE) is 3500 g SPE / g TiCl ₃ . The yield of the soluble fraction of the copolymer is 1.9 wt.% Of the yield of marketable copolymer powder, which meets regulatory requirements. The mass fraction of the fine fraction with a size <60 μm is 0.31 wt.%, Which practically coincides with the same indicator for the homopolymerization of propylene in Example 2. Under the conditions of this example, the TiCl ₃ catalyst particles are not crushed, as at the stage of preliminary processing of the catalyst complex with propylene, and at the stage of copolymerization in reactors.

Examples 17 and 18, comparative in relation to the prototype.

Example 17 (comparative).

Polypropylene is obtained in a manner analogous to example 4 with the difference that the preliminary processing of the catalyst complex with propylene is carried out according to the prototype method in two stages:

a) In the first stage, after thermostating the reactor at 20 ° C under continuous stirring conditions, propylene gas is uniformly dosed into the reactor for three hours. The yield of polypropylene after processing the catalyst complex with propylene is 2.5 g of PP / g of TiCl ₃ .

b) In the second stage, after thermostating the reactor at 40 ° C, hydrogen is introduced into the reactor in an amount of 0.05 g / g TiCl ₃ and, under continuous stirring conditions, propylene gas is additionally uniformly dosed for three hours. 15 minutes after the end of the second stage of propylene dosing, the pressure in the reactor decreased to 0.01 atm, which corresponds to the complete conversion of propylene and the total achieved yield of 5 g PP / g TiCl ₃ .

Under stationary conditions of a continuous process of basic polymerization, the average yield is 4440 g PP / g TiCl ₃ . The isotacticity of PP powder is 98.5 wt.%, The yield of atactic PP is 0.93 wt.% Of the yield of salable isotactic PP, which is the norm. The mass fraction of finely divided fraction with a size of ≤60 μm was 1.2 wt.%.

Thus, pre-treatment of the catalyst complex with propylene under the conditions of the prototype method with a mass ratio of DEACTiCl ₃ = 4 leads to a noticeable fragmentation of the catalyst particles, despite the relatively high yield of PP (5 g PP / g TiCl ₃ ).

Example 18 (comparative).

Polypropylene is obtained by a method analogous to example 17 with the difference that a modification of TiCl _{3 is used} , similar to examples (11-15). The polymer yield is 4200 g PP / g TiCl ₃ . The isotacticity of the obtained PP powder is 98.2 wt.%, The yield of atactic PP-0.91 wt.% Of the yield of isotactic PP. The mass fraction of the fine fraction with a particle size <60 μm was 1.5 wt.%, Which indicates a noticeable fragmentation of the catalyst particles.

Thus, comparative examples illustrate the fact that in the conditions of the prototype method for the process of pre-processing the catalyst complex with propylene, an unsatisfactory result is observed if at this stage the mass ratio DEAC / TiCl ₃ does not meet the requirements of the present invention.

The attached table shows the performance of the above examples. The examples given clarify the invention without limiting it.

The present invention solves the problem of ensuring the efficiency of pretreatment with a propylene catalyst complex (TiCl ₃ + DEAC) for any modifications of TiCl ₃ used in continuous technological processes for producing polypropylene and copolymers of propylene with ethylene, and the proposed method for producing polypropylene and its copolymers with ethylene solves the problem of elimination of crushing of catalyst particles as in the pretreatment step of the catalytic complex (TiCl ₃ + DEAC) with propylene and under wasps ovnoy polymerization (or copolymerization).

As a result, the elimination of the formation of the PP dust fraction minimizes the technological downtime and increases the productivity of the process when producing high-quality polymer powders with a narrow particle size distribution and high bulk density. In the proposed method, the catalyst retains high activity and stereospecificity.

In addition, this invention provides the possibility of targeted regulation of the concentration of cocatalyst during basic polymerization, ensuring the efficiency of the process at the optimum flow rate, the rapid adaptation of process parameters with fluctuating concentrations of inhibitory trace elements in the feed (solvent, monomers, hydrogen).

Table
indicators of the method of producing polypropylene (compiled according to examples 1 ÷ 18). Example No. Reagent loading option number The parameters of prepolymerization treatment of the catalyst The density of the layer of TiCl ₃ in the solvent, g / cm ³ The yield of the PP powder fraction with a particle size <60 μm, wt.% The bulk density of the powder PP, g / cm ³ Isotacticity of PP powder, wt.% (Soluble fraction yield, wt.% Of polymer yield) Concentration, g / l DEAC / TiCl ₃ , wt.%

Exit,

TiCl ₃ DEAH When processing the catalytic system with propylene As part of the complex fed to the reactor 5 2 6.2 4.4 0.71 9 2,5 0.45 0.95 0.45 97.4 (0.75) one 2 6.8 6.8 one 9 2,4 0.45 0.10 0.47 97.4 (0.72) 2 2 6.7 6.7 one 9 2,4 0.45 0.29 0.48 97.6 (0.70) 3 2 6.45 12.9 2 9 2,4 0.45 0.31 0.47 97.5 (0.75) four 2 6.2 24.8 four 9 2.5 0.45 0.82 0.46 98.2 (0.78) 10 2 6.5 13.0 2 9 2,4 0.48 0.95 0.44 97.1 (0.73) 6 2 7.3 29.3 four 9 2.5 0.48 0.14 0.47 97.2 (0.74) 7 2 6.2 24.8 four 9 2,4 0.48 0.35 0.47 97.5 (0.70) 8 2 5.7 40,0 7 9 2.5 0.48 0.75 0.46 97.8 (0.75) 9 one 5.5 49.5 9 9 2.5 0.48 2,55 0.43 97.7 (0.68) 13 2 7.1 7.1 one 9 2.5 0.52 3.92 0.41 97.3 (0.79) fourteen 2 5.2 36,4 7 9 2.5 0.52 0.54 0.46 97.1 (0.72) eleven one 5,0 45.0 9 9 2,4 0.52 0.08 0.47 97.0 (0.77) 12 one 5,0 45.0 9 9 2.6 0.52 0.21 0.49 96.9 (0.73) fifteen one 4.4 52.8 12 12 2.5 0.52 0.67 0.45 97.2 (0.57) 16 2 6.2 6.2 one 9 3.25 0.45 0.32 0.46 (1.90) 17 2 6.8 6.8 one 9 1,0 0.45 1.40 0.42 98.5 (0.93) eighteen one 5,0 45.0 9 9 1,0 0.52 1.15 0.40 98.2 (0.91)

Claims (2)

1. A method of producing a polymer based on propylene, polymerization of a monomer in a hydrocarbon solvent at 20 ÷ 80 ° C and 1 ÷ 30 ati, in the presence of a catalyst of the reaction product of pretreatment of titanium trichloride and diethylaluminium chloride with propylene and using hydrogen as a molecular weight regulator polymer, characterized in that they produce polypropylene or a copolymer of propylene with ethylene with pre-treatment of titanium trichloride and diethylaluminum chloride with propylene before cottage in the main polymerization reactor, which is carried out at a weight ratio of DEAC / TiCl ₃ = 1.10, determined by the initial layer ₃ TiCl particle density in a hydrocarbon solvent, and set in the range: a) 1 ÷ 2 when the density of the layer of the initial titanium trichloride is less than 0.46 g / cm ³ ; b) 3 ÷ 5 when the density of the layer of the initial titanium trichloride in the range of 0.46 ÷ 0.50 g / cm ³ ; c) 6 ÷ 10 when the density of the layer of the initial titanium trichloride is more than 0.50 g / cm ³ , and pretreatment of titanium trichloride and diethylaluminium chloride with propylene before feeding the main polymerization reactor to a conversion of 2.0 ÷ 3.0 g of polymer per 1 g of titanium trichloride in the preparation of polypropylene and to a conversion of 3.0 ÷ 4.0 g of polymer per 1 g of trichloride titanium in the preparation of a copolymer of propylene with ethylene, and after pretreatment of titanium trichloride and diethylaluminium chloride with propylene before metering into the reactor main polymerization DEAC / TiCl ₃ in the weight ratio set forth affairs 6 ÷ 10 by additional dosage calculated amount of diethylaluminum chloride. 2. The method according to claim 1, characterized in that in order to increase the compositional homogeneity of polypropylene or a copolymer of propylene with ethylene, preliminary processing of titanium trichloride and diethylaluminium chloride with propylene is carried out in the presence of hydrogen at the rate of ≤0.01 g of hydrogen per 1 g of titanium trichloride at a partial pressure of hydrogen in gas phase 2 ÷ 10 vol.% of the partial pressure of propylene.