JPS63132905A - Polymerization of olefin - Google Patents

Abstract

PURPOSE:To almost completely prevent fouling phenomenon, by polymerizing an olefin in the presence of a catalyst system composed of an organic Al compound and a solid catalyst component containing Ti and halogen while adding a polyfunctional electron-donative compound to the polymerization system. CONSTITUTION:One or more olefins (e.g. ethylene) are polymerized in a hydrocarbon diluent in the presence of a catalyst system obtained from an organic Al compound (e.g. triethylaluminum) and a solid catalyst component containing Ti and a halogen in the form of a compound. The above polymerization is carried out while adding a polyfunctional electron-donative compound (e.g. N,N,N',N'-tetramethyldiaminomethane, acetolylacetone, etc.) to the reactor. The molar number of the whole functional group of the electron-donative compound is 0.001-0.9 based on 1mol of the organic Al compound. The polymerization operation is stabilized, the temperature control of the reactor is facilitated and a polyolefin having stable quality can be produced by this process.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention involves polymerizing at least one olefin in a liquid phase in the presence of a catalyst to produce a polymer that is substantially insoluble in the liquid phase. In the so-called slurry polymerization method for producing polyolefins, the fouling that occurs in the reactor (referring to the phenomenon in which polymerization reaction product particles in the slurry or solid catalyst particles adhere to the wall of the reactor) is prevented. Regarding the method.

[Foreground of invention]

In so-called slurry polymerization, which is often used to produce polyolefins by polymerizing olefins, a fouling phenomenon in which the polymer sticks to the wall of the reactor sometimes occurs.

When fouling occurs, the smoothness of the walls of the reactor is lost, and the stirring power increases dramatically. At the same time, it becomes difficult to remove reaction heat from the tube walls, making temperature control impossible, and in the worst case, the reaction goes out of control.

Furthermore, once fouling has progressed, it is difficult to remove the deposits during operation, and normal recovery is often not possible unless the reactor is dismantled and cleaned.

-G, in slurry polymerization, polymerization must be carried out at a temperature below the melting point of the polymerization reactant in the solvent used; if this critical temperature is exceeded due to the occurrence of some abnormality, the particles will melt and adhere to the tube wall.

This type of fouling is related to the phase transition of the polymer, is determined by the molecular weight and copolymerization composition of the solvent and polymerization product, and cannot be significantly improved. but,
Fouling will occur even if the reactor temperature is well below this critical temperature.

This phenomenon occurs more easily as the slurry concentration in the reactor increases, and therefore it becomes difficult to increase production above a certain level. Furthermore, if the reactor is operated at its maximum limit, adhesion to the reactor wall will occur discontinuously and unevenly, making it difficult to operate the reactor stably.

[Conventional technology]

As mentioned above, several technologies have been proposed to prevent unsafe operation and maintenance environments (problematic fouling).
Typical examples include a method in which an antistatic agent is present in the polymerization container (for example, JP-A-59-64604), or a method in which polymerization is carried out in the presence of silicone oil (JP-A-59-64604).
86608) etc. Although these known techniques are recognized to be effective to some extent in preventing fouling, the degree of prevention of fouling is still not fully satisfactory.

[Problem that the invention seeks to solve]

An object of the present invention is to solve the problems of the above-mentioned known techniques and to provide a method that almost completely prevents fouling in slurry polymerization of olefins.

[Means for solving problems]

The olefin polymerization method of the present invention is a method in which at least one olefin is polymerized in a hydrocarbon diluent using a catalyst system obtained from a solid catalyst component containing titanium and a halogen in a combined state and an organoaluminum compound. , is characterized in that polymerization is carried out while adding a polyfunctional electron-donating compound into the reactor.

According to the present invention, by using a trace amount of a polyfunctional electron-donating compound, fouling can be completely prevented without affecting the polymerization activity of the catalyst and the physical properties of the resulting polymer. As a result, high productivity, which was previously impossible due to fouling, can be maintained and continued.
In addition, there is no need to shut down the operation and dismantle and clean the reactor due to the progress of fouling, and the productivity and economic efficiency of the manufacturing plant are dramatically improved.

The above-mentioned polyfunctional electron-donating compound is a compound containing two or more electron-donating groups in the molecule and having a structure in which the electron-donating groups are bonded by a so-called inert group. .

The number of inert groups is 1 to 10, preferably 1, counting the number of shortest paths.
It is a hydrocarbon group or a W-substituted hydrocarbon group having ~6 carbon atoms and bonding each electron-donating group. This inert group having a large number of carbon atoms is not preferable because it has a poor fouling inhibiting ability and has a high boiling point, making it difficult to separate it from the resulting polymer product.

The electron donating group possessed by the polyfunctional electron donating compound may or may not have an active hydrogen atom. Specific examples of the electron donating group include the first
Amino group (-NHz), secondary amino group (:0-NH)
, tertiary amino group (miN), nitrile group (-CN), imino group (yuC=N), hydrazone (diC''NNHg,
CH TomiNNH*), hydraphenolic hydroxyl group (-OH
), carbonyl group <:C-O>, carboxyl group (
-COO-), ether group (-0-), phosphoryl group (diP-0゜2, tertiary alkyl and arylphosphine (:1-P-), phosphine oxyto (miP=0)
, thiol (-S H), thioether group (-S-),
Thionyl group (::5=O), sulfuryl group (=SO,
), sulfoxy group (-SOx O-), and the like. Among these, 17th mino group, 27th mino group, tertiary amino group, ether group, alcohol group, carbonyl group, thioether group, and thiol group are preferred, and especially,
Particularly preferred are a primary amino group, a secondary amino group, a 37th amino group, an ether group, and a carbonyl group.

Specific examples of polyfunctional electron-donating compounds include the following. N, N, N', N' -tetramethyldiaminomethane, N, N, N', N'-tetramethyl-
1,1-diaminoethane, ethylenediamine, diethylenetetramine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, N, N, N
',N'-tetramethylethylenediamine, N-methylethylenediamine, N,N'-dimethylethylenediamine, trimethylenediamine, tetramethylenediamine,
Pentamethylene diamine, hexamethylene diamine, polyethyleneimine (average molecular weight 3 million to 1 million), monoethanolamine, jetanolamine, triethanolamine, 0-ethylethanolamine, N-ethylethanolamine, diethylene glycol, triethylene glycol, polyethylene Glycol (average molecule fj
1200 to 60,000), polypropylene glycol (average molecular weight 200 to 10,000), ethylene glycol dimethyl ether, ethylene glycol diphenyl ether, polyethylene glycol monolaurate, polyethylene glycol mono-p-nonylphenyl ether, 0-phenylenediamine, 0-amino Phenol, acetylacetone, acetylacetone, etc.

These polyfunctional electron-donating compounds can be added to the reactor by feeding and adding the pure product as it is, by dissolving it in a non-polar solvent and then adding it, or by pre-mixing it with an organoaluminum compound as a co-catalyst. Either method can be adopted, such as feeding after mixing with the solid catalyst component, or feeding after premixing with the solid catalyst component, but in order to stably express the effect,
Preferably, it is supplied in the form of a non-polar solvent solution.

Examples of non-polar solvents include hydrocarbons, such as aliphatic hydrocarbons such as pentane, hexane, heptane, octane, cyclohexane, and aromatic hydrocarbons such as benzene, toluene, xylene.

The amount of the polyfunctional electron-donating compound added is such that the ratio of the number of moles of all functional groups to the number of moles of the organoaluminum compound is 0.0.
It is desirable that it is 01 to 0.9.

If this ratio is less than 0.001, the fouling prevention effect will be insufficient, and if the ratio exceeds 0.9, the reaction rate will be greatly reduced, and as a result, the resulting polymer Solid catalyst and organoaluminum compound residues increase. Moreover, in some cases, it may adversely affect the physical properties of the polymer, which is not preferable.

The catalyst system consists of a solid catalyst component containing titanium and halogen in a combined state and an organoaluminum compound.

Solid catalyst components containing titanium and halogen in a combined state include titanium trichloride, a eutectic of titanium trichloride and aluminum chloride, and those treated with an electron-donating compound, magnesium and ■valent or ■valent titanium and chlorine. Examples include composites containing 60% by weight or more of main components.

As the organic aluminum compound, those represented by the following general formula are generally used.

AIR' R word R2 and R'R'Al-0-AIR''R' where Rl,
RR and R3 are alkyl groups having at most 14 carbon atoms,
or an alkoxy group, a halogen atom, and a hydrogen atom, of which at least one, more preferably two, are an alkyl group, R4, Rs, R&
, R'+ is an alkyl group or an alkoxy group having at most 14 carbon atoms. Specific examples of these organoaluminum compounds include triethylaluminum, tripropylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, dimethylaluminum chloride, diethylaluminium chloride, diethylaluminum hydride, diethylaluminum ethoxide, ethylaluminum sesquichloride, ethylaluminum dichloride, bis(
(diethylaluminum) oxide and the like.

The proportion of the solid catalyst component (as titanium atoms) and organoaluminum compound used in the polymerization system is generally 0.001 to 1 mol and at most 1 mol each,
Particularly preferred are 0.001 to 0.03 mol and at most 0.1 mol.

Examples of the olefin polymerized by the catalyst system obtained as described above include olefins having at most 12 carbon atoms. Specific examples thereof include ethylene, propylene, butene-1,4-methylpentene-11hexene-11octene-1, etc. In carrying out the present invention, these olefins may be homopolymerized, or
The method of the present invention, which may copolymerize two or more types of olefins, is particularly effective in polymerizing when at least one of the olefins is ethylene.

The polymerization is carried out by a method in which the polymer is not substantially dissolved in the liquid phase of an inert solvent, a so-called slurry polymerization method. Inert solvents used include isobutane, butane, pentane,
Examples include liquid aliphatic hydrocarbons such as hexane, heptane, octane, and liquid paraffin, aromatic hydrocarbons such as benzene, toluene, and xylene, and alicyclic hydrocarbons such as cyclohexane. The raw material olefin itself, such as hexene-1, is also used. These solvents may be used alone or in combination.

〔Effect of the invention〕

According to the method of the present invention, it is possible to prevent reaction product particles or solid catalyst particles from fouling on the reactor wall in slurry polymerization of oleftane, and therefore to suppress an increase in agitator power due to fouling. However, it is possible to prevent a decrease in the heat transfer coefficient of the reactor wall.

By preventing fouling, the olefin polymerization operation becomes stable, the temperature of the reactor can be easily controlled, and the quality of the obtained polyolefin can be stabilized. Also,
Conventionally, it was not possible to increase the slurry concentration due to fouling in the reactor, but according to the present invention, the slurry concentration can be increased by eliminating fouling.
Productivity is improved with a reactor of the same volume. As described above, the present invention is very significant in terms of safety and economy in producing polyolefins.

〔Example〕

The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof.

In the Examples and Comparative Examples, the melt index (hereinafter referred to as "M!") was measured in accordance with JIS -6760 at a temperature of 190° C. and a load of 2.16 kg. Also, the High Load Melt Index (hereinafter referred to as rHLMIJ) is according to JIS -6760 at a temperature of 190°C and a load of 21. (It was measured under the conditions of ikg. Furthermore, the density was determined according to JIS K-6760
Measured according to.

Example l A catalyst in which titanium tetrachloride and vanadium oxytrichloride were supported on anhydrous magnesium chloride using n-hexane as a diluent (titanium content: 7.5% by weight, vanadium content: 6%)
．． 3% by weight (hereinafter referred to as "solid catalyst A") was prepared.

This solid catalyst A and triethylaluminum were continuously supplied to the reactor using an annular reactor having an internal volume of 3,000 ml, and ethylene was continuously polymerized in the presence of hydrogen using n-pentane as a polymerization solvent.

The polymerization conditions were a pressure of 40 kg/cm" and a temperature of 95°C. At this time, solid catalyst A was used as an n-hexane slurry, and triethylaluminum was used as an n-hexane solution at a rate of 0.618/hr (solid (catalyst equivalent) 3.05g/hr () ethylaluminum equivalent)
was continuously fed to the reactor at a rate of .

Further, for the purpose of preventing fouling of the reactor, ethylenediamine diluted with xylene was continuously injected into the reactor so that the molar ratio of ethylenediamine and triethylaluminum was 1/80. At this time, under the condition that the slurry concentration in the reactor is 35%, the stirring power of the circulation pump is 6.5KW, and the overall heat transfer coefficient U of the reactor wall is 1+520 Kcal 7m"
・hr ・'c.

Furthermore, the polymerization activity was 40.000 g/g catalyst, which was substantially unchanged from the case where ethylenediamine was not added. The Ml of the obtained polymer was 1.25 (g/1
0 sin), and the density was 0.9602 (g/cc), and no difference was observed in odor, coloring, or practical physical properties from the additive-free product.

When the hydrogen/ethylene concentration ratio in the reactor was varied under the same temperature and pressure conditions and continuous operation was performed for 30 days to produce polymers ranging from HLMIO, IQ to M2SO4, it was found that regardless of the Ml (HLMI) of the polymers, There was no increase in the stirring power of the circulation pump or any decrease in the overall heat transfer coefficient, and the polymerization operation was extremely stable, making it possible to produce polyethylene at a rate of 31.7 kg/hr without hindrance to continuous operation. did it. When the reactor was dismantled and internally inspected to confirm the presence of fouling after 30 days of continuous operation, the reactor wall was completely unchanged from before the start of polymerization, and no traces of fouling were observed.

Comparative Example 1 Using the same reactor as in Example 1, continuous polymerization of ethylene was carried out using the same catalyst and under the same polymerization conditions without adding ethylenediamine.

At this time, what is the stirring power of the circulation pump when the slurry concentration in the reactor is 35%? , IKW, and the overall heat transfer coefficient is 1.
It was 385 Kcal 7m"・hr・'C.

After that, due to an increase in the stirring power of the circulation pump and a decrease in the overall heat transfer coefficient, it became impossible to maintain a slurry concentration of 35%, so in order to gradually reduce the slurry concentration, the ethylene supply rate was reduced, but continuous operation On day 0, the polymerization temperature became uncontrollable and the polymerization operation was artificially stopped.

After the polymerization operation was stopped, the reactor was dismantled and inspected, and polymer fouling was found all over the reactor wall.

Examples 2 to 4 Using the same reactor as in Example 1, continuous polymerization of ethylene was carried out using the same catalyst and under the same polymerization conditions, varying the amount of ethylenediamine added. The results are shown in Table 1.

Examples 5 to 8 Using the same reactor as in Example 1, continuous polymerization of ethylene was carried out by continuously injecting the same catalyst into the reactor at a rate of 1/g Q. The results are shown in Table 2.

Example 9 with blank spaces below
x, a stainless steel ball with a diameter of 20 mm is placed in a container (apparently 70% filled by volume), the amplitude is 10 mm, and the frequency is 1.
The mixture was attached to a 200-op vibrating ball mill and co-pulverized for 48 hours to obtain a uniform co-pulverized product.

(Hereinafter, referred to as "solid catalyst B.") The titanium content in this solid catalyst B was 6.5% by weight. Using the same reactor as in Example 1, using this solid catalyst B as aluminum, diethylaluminum chloride was continuously fed into the reactor, and n-pentane was used as the polymerization solvent to react with ethylene and butene-1 in the presence of hydrogen. Continuous polymerization was carried out.

The polymerization conditions were a pressure of 40 kg/cm" and a temperature of 75°C. At this time, one solid catalyst B was prepared as an n-hexane slurry.
In addition, diethylaluminium chloride was used as an n-hexane solution at 0.68 g/hr (in terms of solid catalyst) and 3
．． lOg/hr (diethyl aluminum chloride equivalent)
was continuously fed to the reactor at a rate of .

Furthermore, in order to prevent fouling of the reactor, jetanolamine diluted with toluene was continuously injected into the reactor at a molar ratio of 1/40 to diethylaluminium chloride. At this time, the slurry concentration in the reactor was 35%.
Under these conditions, the stirring power of the circulation pump is 6.7 KW, and the overall heat transfer coefficient of the reactor wall is 1+520 Kcal/m"
・hr ・'C.

In addition, the polymerization activity was 35.800 g/g catalyst, which was substantially unchanged from the case where no jetanolamine was added. The Ml of the obtained polymer was 5.12 (g/
10 sin), and the density was 0.9415 (g/cc), and no difference was observed in odor, coloring, or practical physical properties from the additive-free product.

When the system was operated continuously for 30 days under the same conditions, the stirring power and overall heat transfer coefficient of the circulation pump remained almost constant during the continuous operation. As a result, the polymerization operation is very stable, with a speed of 32,2 kg/h without any hindrance to continuous operation.
It was possible to produce polyethylene using r.

Examples 10 to 13 Using the same reactor and the same catalyst as in Example 9, changing the hydrogen/ethylene concentration ratio and the butene-I/ethylene concentration ratio in the reactor under the same temperature and pressure conditions, Continuous polymerization was performed. The results are shown in Table 3.

Examples 14 to 17 in the blank space below: Using the same reactor and the same catalyst as in Example 9, the temperature, hydrogen/ethylene concentration ratio in the reactor, and type of α-olefin used were changed to propylene, hexene, etc. under the same pressure conditions.
Continuous copolymerization with ethylene was performed in place of 14-methylpentene-1. The results are shown in Table 4.

Below are Yohaku Examples 18 to 19 Anhydrous magnesium chloride was pulverized for 12 hours under the same conditions using the same vibrating ball mill as in Example 9 to obtain a homogeneous pulverized product. This pulverized material was loaded with tetra-n-butoxytitanium and tetra-n-butoxyzirconium using toluene as a diluent, and then reduced with ethylaluminum sesquichloride, and the catalyst (titanium content: 7.8% by weight,
Zirconium content: 5.7% by weight, hereinafter referred to as "solid catalyst C"
) was prepared.

Using the same reactor as in Example 1, this solid catalyst C and triethylaluminum as organic aluminum were continuously supplied to the reactor, and ethylenediamine diluted with xylene was added to the reactor to prevent fouling, and the molar ratio between it and triethylaluminum was adjusted. The amount of ethylene and butene-1 was continuously injected into the reactor to be 1/40, and n-pentane was used as a polymerization solvent to carry out continuous copolymerization of ethylene and butene-1.

The polymerization conditions were a pressure of 49 kg/cm'' and a temperature of 90°C.At this time, solid catalyst C was used as an n-hexane slurry, and triethylaluminum was used as an n-hexane solution, each at a rate of 1.53 g/h. r (solid catalyst equivalent)
, 3.22 g/hr (in terms of triethylaluminum). At this time, the stirring power of the circulation pump was 6.5% under the condition that the slurry concentration in the reactor was 35%.
4KW, and the overall heat transfer coefficient of the reactor wall is 1.530
The polymerization activity was 15.550 g/g catalyst, which was essentially the same as when no ethylenediamine was added. Ml is 45.23 (g/
105in), density is 0.9464 (g/cc)
No difference was observed in terms of odor, coloration, or practical physical properties compared to the case without additives.

Under the same pressure and temperature conditions, the butene-l/ethylene concentration ratio and hydrogen/ethylene concentration ratio in the reactor were changed, and Ml
is 0.08 to 100, density is 0.920 to 0.96
When the system was operated continuously for 30 days to obtain a polymer with a temperature of 0.0, the stirring power of the circulation pump and the overall heat transfer coefficient remained almost constant during the continuous operation. As a result, the polymerization operation is very stable, with continuous operation up to 30.8 k without any hindrance.
It was possible to produce polyethylene at g/hr.

Claims (1)

[Claims] 1. Using a catalyst system obtained from a solid catalyst component containing titanium and halogen in a combined state and an organoaluminum compound,
A method for polymerizing at least one olefin in a hydrocarbon diluent, the method comprising polymerizing while adding a polyfunctional electron-donating compound into a reactor. 2. Claim 1, wherein the amount of the polyfunctional electron-donating compound added is 0.001 to 0.9 (number of moles of total functional groups/number of moles of organoaluminum compound) with respect to the organoaluminum compound. the method of. 3. The method according to claim 1, wherein the at least one olefin is ethylene.