JPS6071611A - Process for polymerizing propylene - Google Patents

Abstract

PURPOSE:To obtain the titled polymer, by polymerizing propylene in the presence of a catalyst containing a titanium catalyst supported on a magnesium compound, an organoaluminum compound and a carboxylic acid ester, etc., bringing the unreacted monomer into contact with an organoaluminum compound, evaporating and separating the unreacted monomer, and recovering and reutilizing the monomer without deteriorating the catalyst activity. CONSTITUTION:Propylene is polymerized in the presence of a catalyst consisting of one or more of a titanium halide catalyst supported on a magnesium halide, an organoaluminum compound, e.g. triethylaluminum, and an ester compound such as a carboxylic acid ester, orthocarboxylic acid ester and orthosilicic acid ester, etc. The catalyst is then deactivated with an alcohol having a higher boiling point than ethanol to give the aimed polypropylene. In the process, the unreacted propylene is brought into contact with an organoaluminum compound, evaporated, separated and reutilized for polymerization to polymerize the propylene.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for polymerizing propylene. Specifically, the present invention relates to a method for polymerizing recovered unreacted propylene.

With recent improvements in catalyst performance and advances in bulk polymerization using propylene itself as a medium or gas phase polymerization in which substantially no liquid medium is present, an extremely simplified propylene polymerization process has been realized. It's coming.

Among these, a bulk polymerization method with a relatively high monomer concentration during polymerization or a gas phase polymerization method using a catalyst consisting of a titanium halide catalyst supported on halogenated Maguisium, an organoaluminum compound, and a stereoregularity improver is used as a catalyst. In the method of polymerizing propylene, the resulting polypropylene has high stereoregularity, and the amount of titanium halide catalyst and organoaluminum compound used is small, so the steps of polymerization, deactivation, and deashing are significantly required. It can be simplified to However, since the amount of catalyst used is extremely small, if unreacted propylene is not rigorously purified when recovered and reused, there is a problem that the activity of the catalyst will be significantly reduced when the recovered propylene is used for polymerization. there were.

The inventors of the present invention conducted intensive studies to solve the above problems, and as a result, they discovered that propylene can be recovered and reused through simple purification such as simple distillation by using a specific method, and have completed the present invention.

An object of the present invention is to provide a method for recovering and purifying unreacted propylene using a simple method and utilizing it for polymerization.

The present invention polymerizes propylene using a catalyst consisting of a titanium halide catalyst supported on magnesium halide, an organoaluminium compound, and at least one compound selected from carboxylic acid esters, orthocarboxylic acid esters, and orthosilicate esters. Then, the method for obtaining polypropylene by deactivating the catalyst using an alcohol with a higher boiling point than ethanol is characterized in that unreacted propylene is brought into contact with organoaluminium, evaporated and separated, and reused for polymerization. This invention relates to a propylene polymerization method.

In the present invention, the polymerization of propylene includes not only propylene alone but also copolymerization with other α-olefins such as ethylene, butene-1, hexene-1, and the like.

In the present invention, a catalyst system consisting of a titanium halide catalyst supported on magnesium halide, an organoaluminum compound, and at least one compound selected from carboxylic acid esters, orthocarboxylic acid esters, and orthosilicate esters is particularly preferred. Limited Hana (, Tokuko Sho 39-1
Since the proposal in No. 2105, many improved catalyst systems have been proposed, and many known catalyst systems are applicable. The supported titanium rogenide catalyst can be obtained by co-pulverizing magnesium chloride and an organic compound containing a C-0 bond and then contacting it with titanium tetrachloride, or by reducing the hydrocarbon content with a compound such as alcohol. Examples include those obtained by supporting an organic compound containing a C-O bond and titanium tetrachloride on a carrier obtained by precipitating solubilized magnesium chloride with a metal halide or an organometallated metal compound. Examples of carboxylic acid esters, orthocarboxylic acid esters, and orthosilicate esters include ethyl acetate, methyl acrylate, ethyl methacrylate, methyl benzoate, methyl toluate, ethyl toluate, methyl orthobenzoate, ethyl orthotoluate, and orthoacetic acid. Methyl, methyl orthoacetate, ethyl orthoformate, tetranidoxinlan, tetramethoxysilane, tetrapropoxysilane and the like can be used alone or as a mixture of two or more. As the organoaluminum compound, trialkylaluminum such as triethylaluminum, tripropylaluminum xyl oleuminium, etc., dialkylaluminum chloride such as diethylaluminum chloride, dipropylaluminum chloride, dibutylaluminum chloride, diakylaluminum chloride, etc. are preferably used. .

The polymerization method used in the present invention is a solvent polymerization method using an inert hydrocarbon medium, a bulk polymerization method using a liquid monomer itself as a medium, or a gas phase polymerization method without a liquid medium. can.

In the present invention, alcohols with high boiling points include higher alkyl alcohols such as propyl alcohol, butyl alcohol, and hexyl alcohol, or polyethylene glycol monoether, such as ethylene glycol monomethyl ether. , diethylene glycol monoethyl ether, diethylene glycol monoisopropyl ether, triethylene glycol monomethyl ether, etc. Among them, polyethylene glycol monoether is preferably used.

In the present invention, as the organoaluminum used when unreacted propylene is brought into contact with the organoaluminum, the above-mentioned organoaluminum used in the polymerization catalyst is preferably used.

The method for recovering and reusing unreacted propylene is to recover the unreacted propylene by evaporation, contact it with organic aluminum, and then remove the organic aluminum. It is preferable to separate it from the organoaluminum by contacting it and then evaporating and recovering it. The amount of organoaluminum added varies depending on the catalyst system and the amount of catalyst used, so it is not constant, but it is usually 1 to 10 to propylene.
It is sufficient to add 00 wt ppm.

By applying the method of the present invention, recovery and reuse of propylene becomes extremely easy and has great industrial value.

EXAMPLES The present invention will be explained in more detail below with reference to Examples.

Reference Example 1 A) Supported titanium halide catalyst A vibratory mill equipped with two pulverizing pots each having an internal volume of 600 and containing 80 steel balls each having a diameter of 12 m5 is prepared.

Each bottle contained 207 g of magnesium chloride, 2 m of ethyl orthoacetate, and 3 rnl of 1,2-dichloroethane under a nitrogen atmosphere and was pulverized for 40 hours. The pulverized product 102 was placed in a 200+J round bottom flask purged with nitrogen and heated to 50-
of titanium tetrachloride was added, stirred at 80°C for 2 hours, left to stand, the supernatant was removed, and then 100 rn of n-heptane was added.
, stirred at room temperature for 15 minutes, left to stand, and removed the supernatant, a washing operation repeated 7 times.
0 ml was added to form a compatible titanium rogenide catalyst.

B) Polymerization 1 5US- with an internal volume of 500 t which was sufficiently dried and purged with nitrogen.
300 t- of propylene was placed in an autoclave manufactured by No. 32, and further n-hebutane 5 was added thereto... 27 titanium chloride catalyst slurry, 2 diethyl aluminum chloride.
After adding 4 rnl, 14 mA of methyl p-toluate, and 5 ml of triethylaluminum and stirring, the mixture was charged into an autoclave with hydrogen and 16 ont, and the internal temperature was raised to 75°C by heating the autoclave with hot water.
The temperature was raised to 75 DEG C., and polymerization was carried out over a period of 3 hours while charging 25 tons of triethylaluminum diluted with 5 tons of n-hebutane and 140 tons of liquid propylene. After polymerization, 500 ml of diethylene glycol monoisopropyl ether was added to stop the polymerization, and the mixture was allowed to stand still for about 20 minutes.
0t was transferred to a separately prepared 5007 autoclave and recovered propylene.

C) Polymerization 2 Polymerization is carried out using propylene having the same composition as used in Polymerization 1.

Prepare a dry autoclave with an internal volume of 5 tons that is sufficiently purged with nitrogen.

In a 200 ml flask, 50 μm of a titanium halide catalyst obtained with n-heptane (50-1A), 0.32 μm of diethylaluminum chloride, and 0.12 μm of methyl toluate were added.
1. Add 0.20ml of triethylaluminum and mix well, then charge the autoclave and propylene.
5 kg and 1.6 Nt of hydrogen were charged, the internal temperature was raised to 75°C, and polymerization was carried out at 75°C for 1 hour. Thereafter, unreacted propylene was purged, the powder was taken out, dried at 60°C for 20 hours, weighed, and the yield of polymer per titanium catalyst was calculated to be 12,000 t/t-cat. The intrinsic viscosity of the powder (measured in a tetralin solution at 135°C, hereinafter abbreviated as η) was 1.62. Further, the residual ratio after extraction with boiling 11-hebutane (abbreviated as 6 hours of extraction with boiling 1]-hebutane using a Soxhlet extractor) was measured, and II was 960.

Comparative Example 1 The recovered propylene obtained in Reference Example IB) was distilled using a pressure-resistant distillation vessel with a pot volume of 50 tons and a number of theoretical plates of 6 at a reflux ratio of 5 at a top temperature of 77°C and a bottom temperature of 138°C to obtain propylene of approx. Obtained 35t.

Using this propylene, polymerization was carried out in the same manner as in Reference Example 1C) Polymerization 2, and the yield was 8500 f//! -cat
, η1.62, ll96. It was D.

Example 1 0.2 rnl of triethylaluminum was added to 1.5 kg of propylene obtained in Comparative Example 1, stirred for 5 minutes, and then evaporated (at 50°C) to separate triethylaluminum, yielding 1.48 kg of propylene. Obtained.

Using the obtained propylene, polymerization was carried out in the same manner as in Comparative Example 1. The yield was 119oor/f-cat, 771. +
S4, ll96.3.

Reference Example 2 Recovered propylene was obtained by polymerizing in the same manner as B) using the catalyst of Reference Example IA) except that methyl orthoacetate was used instead of methyl toluate.

Comparative Example 2 Polymerization was carried out using distilled propylene in the same manner as in Comparative Example 1, except that the recovered propylene obtained in Reference Example 2 was used. As a result, the yield is 76001/f-cat, η1,67, ll96
．． It was 1.

Example 2 Polymerization was carried out using propylene obtained by distillation in Comparative Example 2 and propylene treated in the same manner as in Example 1, except that triisobutylaluminum was used instead of triethylaluminum. The result was a yield of 12,100 t/f-ca.
t, η161, ll96.0.

Reference Example 6 Reference Example 1 except that ethylene glycol monomethyl ether was used instead of diethylene glycol monoisopropyl ether. Recovered propylene was obtained in the same manner as B).

Comparative Example 6 Polymerization was carried out using propylene obtained by distillation in the same manner as in Comparative Example 1, except that the recovered propylene obtained in Reference Example 6 was used. As a result, the yield was 8800g/g-cat, η164, l
It was 19S, 2.

Example 4 Polymerization was performed using propylene treated with triethylaluminum in the same manner as in Example 1 except that the distilled propylene obtained in Comparative Example 6 was used. As a result, the yield was 12,100 fl/
? -cat, η165.1196.3.

patent applicant Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Scope of Claims] 1) A catalyst comprising a titanium halide supported on magnesium halide, an organoaluminum compound, and at least one compound selected from carboxylic acid esters, orthocarboxylic acid esters, and ornosilicate esters. In this method, the unreacted propylene is brought into contact with organoaluminium, separated by evaporation, and reused for polymerization. 1. A method for polymerizing propylene, characterized by: 2) The method according to claim 1, wherein the polymerization is carried out by a bulk polymerization method using propylene itself as a medium or a gas phase polymerization method in which substantially no liquid medium is present. 3) Alcohols with a higher boiling point than ethanol have the general formula R-(
0C2I-15) n -OH (in the formula, R has 1 to 10 carbon atoms
Claim 1 is a glycol monoalkyl ether represented by an alkyl residue (n is an integer of 1 or more)
The method described in section.