JPS6140307A - Method of recovering diluent - Google Patents

Abstract

PURPOSE:To recover a reusable diluent containing no impurity, by diluting a catalyst such as a solid transition metal catalyst, an organoaluminum compound, a high-boiling ester, etc., polymerizing propylene, introducing an inert gas to a distillation column, and distilling an inert hydrocarbon. CONSTITUTION:A catalytic system comprising a solid transition metal catalyst containing a titanium halide, an organoaluminum compound, and one or more of ester, ether, orthoester, alkoxysilicon, glycol ester, etc. having >=150 deg.C boiling point at normal pressure is diluted with an inert hydrocarbon compound having 60-140 deg.C boiling point at normal pressure, and propylene is polymerized by the use of propylene itself as a medium. Then, an inert hydrocarbon is distilled and separated as distillate at <=140 deg.C containing no compound having >=150 deg.C boiling point by the use of a distillation column having the inert gas inlet 1 below the condensation part 3 at the top of the distillation column while introducing an inert gas into it, and the distillate is recovered in the reservoir 5.

Description

Detailed Description of the Invention The present invention provides an inert hydrocarbon compound used at least as a catalyst diluent when polymerizing propylene to obtain polypropylene by a bulk polymerization method using propylene itself as a polymerization medium or a gas phase polymerization method. Regarding the collection method.

BACKGROUND OF THE INVENTION Recent improvements in catalyst performance have led to superior catalysts, while advances in polymerization have led to the development of methods that do not use inert hydrocarbon compounds as polymerization media, such as bulk polymerization or gas phase polymerization. Processes that use almost no Q inert hydrocarbon compounds are being developed through legal polymerization.

Problems to be Solved by the Invention However, the use of inert hydrocarbon compounds used in your company is extremely small compared to the polypropylene obtained even with the above method, but when the catalyst is charged into a polymerization tank, inert hydrocarbon compounds are used. It is generally done by diluting it into one substance,
Furthermore, inert hydrocarbon compounds are charged to certain parts such as valves to prevent blockage, so a Kana 9 amount of inert hydrocarbon compounds are used, so it is easy to save resources. It is desirable to collect and reuse it by some method.

Means for Solving the Problems As a result of intensive study on methods for solving the above problems, the present inventor discovered that it is possible to recover inert hydrocarbon compounds that can be reused by distilling them using a specific method. Heading Completing the Invention.

That is, the present invention comprises a solid transition metal catalyst containing titanium halide, an organoaluminum compound, and at least one member selected from esters, ethers, orthoesters, alkoxy silicones, and glycol ethers having a boiling point of 150° C. or higher measured at normal pressure. The above polymerization is carried out using a polymerization method using propylene itself as a medium using a catalyst system consisting of a compound. The inactive□
In this method, inert hydrocarbon compounds are collected and reused at normal pressure while introducing inert gas using a distillation column that has an inert gas inlet below the condensation section at the top of the column. Noester with a measured boiling point of 150°C or higher,
The present invention relates to a method for recovering a diluent, which is characterized in that it is recovered by distillation as a fraction of 140° C. or lower, which does not contain ether, orthoester, alkoxy silicon, or glycol ethers.

In the present invention, the solid transition metal catalyst containing titanium halide may contain titanium halide as an active transition metal component, and may also contain aluminum halide, magnesium halide, silica, A so-called carrier-type catalyst, in which titanium halide is supported on a carrier such as alumina, has a boiling point of 1 when measured at normal pressure.
A compound such as an ester, ether, orthoester, amine, or amide at a temperature of 50° C. or higher may be present.

In the present invention, the organoaluminum compound is not particularly limited, but preferably triethylaluminum,
Trialkyl aluminum such as tripropyl aluminum and triimbutyl aluminum, dialkyl aluminum monohalides such as diethylaluminum chloride and dipropyl aluminum chloride, alkyl aluminum sesquihalides such as ethyl aluminum sesquichloride, and alkylaluminum such as ethyl aluminum dichloride. Cibalide or haalkyl aluminum sulfate can be used.

In the present invention, the boiling point measured at normal pressure during polymerization is 15
Ethers, orthoesters, alkoxy silicones, or glycol ethers having a temperature of 0° C. or higher are used as stereoregularity improvers or catalyst activity improvers. If the boiling point measured at normal pressure is lower than 150°C, separation from inert hydrocarbon compounds will not be easy, which is undesirable. Specific compounds include monoalkyl esters, dialkyl esters, aromatic ethers or zo- or triethylene glycol, diethers or monoalkyl ethers of propylene glycol, aromatic orthoesters, di-, tri-, tetra- Ethoxysilane is mentioned. More specifically, benzoic acid, toluyl, anisyl, methyl naphthylate, ethyl, propyl, ethyl nato ester, diphenyl ether, dibenzyl ether, amyl ether nato ether, methyl orne benzoate, ethyl orthobenzoate, orthotoluyl. Orthoesters such as ethyl acid, ethyl orthotoluate, methyl orthoanisate, methyl orthoanisate, diethylene glycol, dipropyl ether, diethylene glycol diethyl ether,
Triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol dipropyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, diethylene glycol diethyl ether, diethylene glycol monoisozolopyl ether, triethylene glycol monomethyl ether, Examples include triethylene glycol monopropyl ether, tetraethoxysilane, triethoxymethylsilane, phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, and diphenyljethoxysilane.

In the present invention, the boiling point of the inert hydrocarbon compound at normal pressure must be 60 to 140°C; if it is lower than 60°C, it will not be easy to separate it from propylene;
If it is higher, separation from the above-mentioned esters, ethers, orne esters, glycol ethers, or alkoxy silicones is not easy.

Specific examples of inert hydrocarbon compounds include hexane, heptane, octane, benzene, toluene, xylene, ethylbenzene and mixtures thereof.

The inert hydrocarbon compounds recovered in the present invention are those used as diluents for charging solid transition metals in the form of slurry into the polymerization reaction zone, or those used as diluents for the safety of organoaluminum compounds. Examples include those charged with the solid transition metal catalyst, and those charged to prevent the habulp etc. from being blocked by the polymer. An inert hydrocarbon compound used as a catalyst is essential.

The polymerization reaction is carried out by a bulk polymerization method using zolopyrene itself as a liquid medium or a gas phase polymerization method in which substantially no liquid medium is present, and the amount of inert hydrocarbon compound used is the monomer or the resulting polymer. The present invention is effective when the amount is extremely small compared to .

In other words, if a large amount of inert hydrocarbon compound is used, the polymerization-inhibiting components that are probably generated during polymerization can be separated by distillation in a relatively small amount61 into an amount that does not substantially affect the catalyst performance. This is because it is relatively easy to do so.

The inert hydrocarbon compounds recovered in the present invention include those recovered as high-boiling components from recovered unreacted monomers such as ethylene and propylene, or high-boiling components recovered during drying of I-lipropylene powder, etc. can be mentioned. Production of solid transition metal catalysts using these recovered inert hydrocarbon compounds In order to use the acid as a diluent, it is required to rectify it very precisely to separate the inert hydrocarbon compounds. It is necessary to remove a large amount of low-boiling and high-boiling components using a distillation column with a large number of plates, which results in a low yield of purified inert hydrocarbon compounds and increases purification costs.

On the other hand, in the method of the present invention, a distillation column with a number of plates sufficient to remove esters, ethers, orthoesters, or hagelicol ethers at a temperature of 150°C or higher is used, and an inert gas inlet is provided below the condensation section at the top of the column. By carrying out distillation while introducing an inert gas using a distillation column having a distillation column, a recyclable amount of inert hydrocarbon compounds can be recovered and utilized.

Distillation may be carried out either continuously or batchwise, and the number of stages required is usually several.

In addition, the inert gas inlet is located below the condensation section and is located at a point where the above-mentioned esters, ethers, orthoesters, or bald glycol ethers (hereinafter referred to as fractions with a boiling point of 150°C or higher) can be completely removed. It is sufficient if it is above a sufficient number of stages. If the number of stages is below p enough to remove the fraction at 150°C or higher, 15
This is because a fraction with a temperature of 0°C or higher is distilled out. Examples of the inert gas used in the present invention include nitrogen gas and helium gas. The flow rate of the inert gas is 1/10 of the volume considering the rising steam flow reaching the condensing section as a gas.
An amount of 0 to 1/10 is preferable; an amount of Ql/100 or less is insufficient, and an amount of Ql/100 or more is not preferable because inert hydrocarbons to be recovered are entrained in the inert gas, resulting in a decrease in yield.

Function: It is presumed that the method of the present invention effectively removes polymerization-inhibiting components with relatively low boiling points, so that the diluent can be recovered with simple operations.

Example The present invention will be further explained with reference to Examples below.

Example 1 Production of a Concerned Solid Transition Metal Catalyst A vibratory mill equipped with two grinding pots each having an internal volume of 900 - containing 80 steel balls with a diameter of 12+ m was prepared. In this pot under a nitrogen atmosphere, 1 kg of magnesium chloride 30
I! , 3 ml of orthoethyl acetate.

6d of 1,2-dichloroethane was added and pulverized for 40 hours.

From the crushed product obtained by repeating this operation twice, 8
2 using 0g! titanium tetrachloride 500 in a round bottom flask
- After contacting with stirring at 80° C. for 2 hours, it was placed in a device and the supernatant liquid was removed. Next, add n-hebutane IJ and stir at room temperature for 15 minutes.
After stirring for a minute, the apparatus was washed, and the supernatant liquid was removed.The washing operation was repeated seven times, and then 500 g of n-heptane was further added to prepare a solid transition metal catalyst slurry.

(Preparation of noD catalyst slurry: 5011 diethylaluminum chloride 214-, methyl toluate IGOd were added as a solid component to the solid transition metal catalyst slurry in n-heptane 50! to prepare a catalyst slurry. Separately, triethylaluminum 133- was added to n-heptane 50! - Diluted in 20! of heptane.

01: In the apparatus shown in Figure 1, A is a polymerization reactor with an internal volume of 500 i. The slurry obtained by polymerization in A is sent to autoclave C (internal volume 200 #) via line 15 and pump B. , a portion of the slurry is recycled to A.

At C, a catalyst deactivator (diethylene glycol monoinzolovyl ether) is added and the slurry is discharged through 16 and heated through a heated tube to remove most of the media (propylene and n-
Heptane) is separated in cyclone G, and the powder is sent to H for further drying. Drying is carried out by introducing propylene heated to 90°C into the heat exchanger F through the line 18. The recovered material, which has been cooled and liquefied at 30° C., is sent to the tanker via line 20. On the other hand, the steam mainly composed of propylene taken out from line 17 is transferred to heat exchanger E at 0.1 kg/d-gauge, 30
The recovered material, which has been cooled to ℃ and liquefied, is sent to the tanker via line 19. Gases that do not liquefy are connected to line 21.2, respectively.
2 and 23, it is sent to a propylene recovery system.

Using this apparatus, the following polymerization and n-hebutane recovery operations are performed.

A catalyst slurry (3.9 parts/hour as a solid catalyst), triethylaluminum (8 sd/hour), and propylene (9 parts/hour in 80°C) were charged into polymerization reactor A, and polymerization was carried out at 70°C. At this time, n-
5 Hebutane! / hour.

On the other hand, the polymerization slurry is sent from A to C in 80 to 7 hours.
In C, the catalyst was further deactivated by feeding triethylene glycol monomethyl ether at 100 d/hour. Deactivated slurry is discharged from C at a rate of 80 kg/hour, and is transferred to dryer H.
More liquid was removed in about 30 hours, while liquid was collected in tank I at 9.6 J/hour. The theory is that this recovered liquid, mostly consisting of n-hebutane, has an inert gas inlet line l at the top and a shelf below the inert gas inlet, as shown in Figure 1. Using a distillation column with 5 plates, reflux ratio 1.0, rising vapor amount 15 sd
/min, using nitrogen as an inert gas, and the amount introduced was:
Distillation was carried out at a rate of 50 d/min, and the distillate was taken out until the temperature of the pot reached 170° C. and the upper part of the distillation column reached 100° C. without removing the low-boiling fraction. No methyl toluate, diethylene glycol, or monoisozorobyl ether was detected in the distilled n-hebutane.

The yield of distillate was 90% based on the liquid taken out from the tank. This recovered butane is used as recovery liquid 1. Further, heptane distilled without introducing nitrogen into the inert gas inlet was used as recovered liquid 2.

(0Using the above recovery liquids 1 and 2, the same operation as in the prison section (
However, the crushed material is 10I! Solid transition metal catalysts were produced using scales.

(2) Polymerization reaction: Polymerization was carried out using the solid transition metal catalyst obtained in (C) and the one obtained as a comparison. Polymerization reaction has an internal volume of 5
30xJ of solid transition metal catalyst in the autoclave of i) Methyl toluate 0.06 m, Diethylaluminium chloride 0.128 m,) Liethyl aluminum 0.08 m,
Mix and charge 50 mm of diluent n-hebutane (all using the same n-hebutane used in the experiment), then add 1.5 mm of propylene.
After adding 5 kg of 71PF1.5N7 and polymerizing at 75°C for 2 hours, unreacted polypyrene was purged and drying was carried out under reduced pressure at 60°C to obtain a powder (6 hours at 20 μHg).

Example 2 Example 1 Using highly active titanium trichloride TGY-24 manufactured by Marubeni Solve-A (contains 921 as Tics and 8 other high-boiling point ethers) as a solid transition metal catalyst
Polymerization was carried out using the same apparatus as in (B).

As the catalyst slurry, the above titanium trichloride 1001?1)
Luene 100#, diethyl aluminum chloride 80
5001 of zoropylene was charged and stirred for 1 hour at 40°C to polymerize 1 p"hvsi of titanium trichloride in propylene. Next, 0.5 of diethylene glycol monoisozorobyl ether was added and this was made into a catalyst slurry. This catalyst slurry was used as a solid transition metal catalyst.
Example Bn) (Polymerization was carried out in the same manner as in iD, except that triethylaluminum was not charged at 100 hr.), using a pump and toluene for 7 lashings of the pulp. Ta.

The recovered liquid consisting mostly of toluene was used in Example 1 (
B) Toluene was recovered in the same manner as in (ii) and distilled by introducing an inert gas (helium) (recovered liquid 1)
and one obtained by distillation without introduction (recovered liquid 2). The yields were 86% and 87%, respectively.

10 titanium trichloride catalyst for each recovered toluene.
After adding 011/Z and stirring for 20 hours, the catalyst slurry was used for polymerization. A catalyst slurry consisting of 100,719 titanium trichloride, 0.8-1 diethylaluminum chloride, 100 d of toluene for dilution (however, the same toluene used in the previous polymerization was used) was charged, and propylene 1.
Example 1: 5 kg, hydrogen 3NA, polymerized at 70°C for 3 hours
- Powder was obtained in the same manner as in (b). The results are shown in the table.

Implementing the method of the invention as also shown in the effect examples
), it is possible to recover an inert hydrocarbon compound in a high yield that does not adversely affect the catalyst performance, which is industrially valuable.

[Brief explanation of the drawing]

Figure 1 is a diagram showing an example of the position of the inert gas inlet at the top of the distillation column. 1 is the inert gas inlet, 2 is the line that leads the rising steam to the condenser 3, and 4 is the inert gas inlet. A gas purge line, 5 a condensate reservoir, 6 a condensate reflux line, and 7 a distillate distillation line. Figure 2 is a polymerization flow sheet, A; polymerization tank, B;
Pump, C; deactivation tank, D, E, F: heat exchanger, G; cyclone, H; dryer, work; tank, J, J': pulp,
11; Deactivation side charging line, 12: Propylene charging line, 13.14: Catalyst charging line, 15; Slurry circulation line, 16: Slurry discharge line, 17.18: Recovery steam line, 19.20; Recovery Liquid line, 21, 22.2
3: Uncondensed gas line, 24; Dry gas charging line, 2
5: Drying powder discharge line.

Claims (1)

[Claims] A catalyst consisting of a solid transition metal catalyst containing titanium halide, an organoaluminum compound, and at least one compound selected from esters, ethers, orthoesters, alkoxy silicones, and glycol ethers having a boiling point of 150°C or higher measured at normal pressure. The above polymerization is carried out using a polymerization method using propylene itself as a medium using at least an inert hydrocarbon compound having a boiling point of 60 to 140°C measured at normal pressure as a catalyst diluent. In this method, inert hydrocarbon compounds are measured at normal pressure while introducing inert gas using a distillation column that has an inert gas inlet below the condensation section at the top of the distillation column. 1. A method for recovering a diluent, which comprises distilling and recovering a fraction having a boiling point of 140° C. or lower that does not contain esters, ethers, orthoesters, alkoxy silicones, or glycol ethers having a boiling point of 150° C. or higher.