KR102069554B1 - Process for producing aromatic polycarbonate - Google Patents

Abstract

[PROBLEMS] To provide a method for preventing long-term, stable production of aromatic polycarbonate on an industrial scale, by preventing clogging due to the sticking of the effluent of the scrubber and its surrounding pipe.
[Measures] The aromatic dihydroxy compound and the diaryl carbonate are used as raw materials using a production apparatus in which the porous plate-shaped polymerizer 2 and the scrubber 11 are connected via a pipe (A) 10. In the production of the aromatic polycarbonate, the effluent containing the by-produced aromatic monohydroxy compound, unreacted aromatic dihydroxy compound, diaryl carbonate, and accompanying condensate is subjected to polymerization under reduced pressure. From (2), the aromatic polycarbonate was polymerized by transesterification while extracting the scrubber 11 through the pipe A and using the scrubbing liquid to condensate and dissolve the effluent. In addition, the connection position of the piping A which connects the polymerization reactor 2 and the scrubber 11 is a linear motion part of a polymerization reactor, and shall be the lower half side of a linear motion part.

Description

Production method of aromatic polycarbonate {PROCESS FOR PRODUCING AROMATIC POLYCARBONATE}

The present invention relates to a process for producing aromatic polycarbonates.

Conventionally, aromatic polycarbonates are widely used in many fields as engineering plastics excellent in heat resistance, impact resistance, transparency, and the like.

Various researches are conventionally performed about the manufacturing method of this aromatic polycarbonate, Among them, an aromatic dihydroxy compound, for example, 2, 2-bis (4-hydroxyphenyl) propane (henceforth bisphenol A) Interface polycondensation of phosgene and phosgene have been industrialized.

However, in the interfacial polycondensation method, the device is corroded by toxic phosgene, chlorine-containing compounds such as by-product hydrogen chloride or sodium chloride and methylene chloride used in large quantities as a solvent, and further, adverse effects on the polymer properties. It has problems such as impurities such as sodium chloride and difficulty in separating residual methylene chloride.

On the other hand, a method for producing an aromatic polycarbonate from an aromatic dihydroxy compound and a diaryl carbonate, for example, bisphenol A and diphenyl carbonate is transesterified in a molten state to polymerize while extracting a by-product phenol. The transesterification method is known.

Unlike the interfacial polycondensation method described above, the transesterification method has an advantage such as not using a solvent.

Conventionally, various polymerization apparatuses are known as a polymerization apparatus for producing aromatic polycarbonate by the transesterification method.

In these polymerization apparatuses, aromatic monohydroxy compounds and the like, which are produced as by-products with the progress of polymerization, are guided to a condenser to condense and extracted.

However, as described above, when the aromatic monohydroxy compound generated from the polymerizer is directly led to a condenser and condensed, it is necessary to lower the temperature of the condenser in order to condense the aromatic monohydroxy compound or the unreacted substance. Effluents, such as condensates, adhere to the inside of the condenser or to the exhaust pipe connecting the condenser and the vacuum device, and gradually reduce the vacuum evacuation capacity, and finally, the tube is closed to make continuous operation of the polymerization device impossible. have.

In order to solve the above-mentioned problem, the technique for efficiently condensing effluents, such as an aromatic monohydroxy compound, is proposed.

For example, (a) the vapor pressure in 190 degreeC is 50-500 mmHg, (b) melting | fusing point is 30 degrees C or less, (c) 5 mass% of aromatic polycarbonates of number average molecular weight 2500 at 25 degreeC. In the scrubber which has the compound for scrubbing liquid which melt | dissolves above, the technique of condensing and dissolving outflows, such as said aromatic monohydroxy compound, is disclosed (for example, refer patent document 1).

Japanese Patent Laid-Open No. 2000-128975

However, in the technique disclosed in Patent Literature 1, when an industrial scale is carried out, an amount of effluent exceeding the solubility of the scrubbing liquid flows into the scrubber, and an insoluble effluent is sprayed or scrubbed provided in the scrubber. There is a problem of blocking a pipe through which liquid flows.

Similarly, on an industrial scale, the effluent cooled in the pipe connecting the polymerizer and the scrubber, the pipe connecting the scrubber and the vacuum pump is fixed to the inner surface of the pipe, etc., and the fixed effluent is fixed to the scrubbing liquid. It does not melt | dissolve by not contacting, and there also exists a problem of blocking a piping.

Therefore, in this invention, aromatic polycarbonate is produced, extracting the effluent containing the by-product aromatic monohydroxy compound, unreacted material, and accompanying condensate by a transesterification method from the polymerizer of a porous plate type with a support body. A method for producing an aromatic polycarbonate in which the scrubber and the effluent in the peripheral pipe of the scrubber are prevented from being blocked and the blockage caused by the fixation can be prevented and the aromatic polycarbonate can be stably produced for a long time. The purpose.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to solve the above-mentioned subject, the present inventors discovered that the subject of the prior art mentioned above can be solved by improving the scrubber and the surrounding piping of a scrubber, and came to complete this invention.

In the present invention, by improving the scrubber and the scrubber peripheral piping, it is possible to effectively prevent clogging trouble due to the sticking and sticking of the effluent from the scrubber and the scrubber peripheral piping, thereby making it possible to stably produce the aromatic polycarbonate for a long time. It turns out that it can. In other words, it has been found by the present invention that all the problems arising in condensing the effluent when the aromatic polycarbonate is produced on an industrial scale by the transesterification method can be solved.

That is, this invention is as follows.

〔One〕

Using the manufacturing apparatus in which the porous plate-shaped polymerizer with a support body and the scrubber are connected through the piping (A),

As a manufacturing method of aromatic polycarbonate which uses an aromatic dihydroxy compound and a diaryl carbonate as a raw material, and produces an aromatic polycarbonate,

The effluent containing the by-produced aromatic monohydroxy compound, unreacted aromatic dihydroxy compound, diaryl carbonate, and condensate accompanying them is, under reduced pressure, from the polymerizer through the pipe (A). With scrubber,

Using a scrubbing liquid in the scrubber to polymerize the aromatic polycarbonate by transesterification while condensing and dissolving the distillate,

The connection position of the said pipe (A) which connects the said polymerizer and the said scrubber is a linear part of the said polymerizer, and is the lower half side of the said linear part,

Process for the production of aromatic polycarbonates.

〔2〕

The inner diameter of the straight part of the scrubber is 200 to 2500mm,

The internal diameter of the said piping (A) which connects the said polymerizer and the said scrubber is the manufacturing method of the aromatic polycarbonate as described in said [1] whose internal diameter of the linear part of the said scrubber is 0.5 times or more.

[3]

The said piping (A) which connects the said polymerizer and the said scrubber is heated at 100-300 degreeC, The manufacturing method of the aromatic polycarbonate as described in said [1] or [2].

〔4〕

In the piping (A) connecting the polymerizer and the scrubber,

The manufacturing method of the aromatic polycarbonate in any one of said [1]-[3] in which the downward inclination of 1/100 or more is formed in the direction toward the said scrubber from the said polymerization machine.

[5]

The scrubber is connected to the transfer pump for transferring the scrubbing liquid through a pipe,

The pipe which connects the said scrubber and the said transfer pump is provided with the filter,

The filter is a suction side of the transfer pump, is installed at the same height as the transfer pump,

The filter is a filter having a capacity of 1 to 200 liters with an element of 10 to 200 mesh inserted therein,

The manufacturing method of the aromatic polycarbonate in any one of said [1]-[4].

[6]

In the pipe (B) connecting the scrubber and the filter,

The manufacturing method of the aromatic polycarbonate as described in said [5] in which the downward inclination of 1/100 or more is formed in the direction toward the said filter.

[7]

The scrubber is connected via a vacuum pump and a pipe (E),

The aromatic poly according to any one of the above [1] to [6], wherein the pipe E connecting the scrubber and the vacuum pump is heated to 100 to 250 ° C and purged with an inert gas of 0.5 to 200 N liter / hr. Method for preparing carbonate.

〔8〕

Piping (E) for connecting the scrubber and the vacuum pump,

The manufacturing method of the aromatic polycarbonate as described in said [7] which has a downward inclination toward the said vertical direction from the said scrubber connection part, and then toward the said vacuum pump.

[9]

The feed pump of the scrubbing liquid and the spray port arranged in the scrubber are connected via a pipe (D),

During the shutdown of the manufacturing apparatus,

The scrubber,

Piping (B) for connecting the scrubber and the filter,

The filter,

Piping (C) for connecting the filter and the transfer pump of the scrubbing liquid,

Pipe (D) connecting the scrubbing liquid transfer pump and the spray port

Venting steam to

Also,

The scrubber, the filter and the pipes (B) to (D) are cleaned in full liquid with an aromatic monohydroxy compound,

The manufacturing method of the aromatic polycarbonate in any one of said [5]-[8].

[10]

The method for producing an aromatic polycarbonate according to any one of the above [1] to [9], wherein the scrubbing liquid contains an alkylaryl carbonate.

According to the present invention, it is possible to effectively prevent scrubbers and blockages due to sticking and sticking of effluent in the peripheral pipes of scrubbers, and to produce aromatic polycarbonates capable of stably producing aromatic polycarbonates on an industrial scale for a long time. It may provide a method.

FIG. 1: shows schematic schematic diagram of an example of the manufacturing apparatus used by the manufacturing method of the aromatic polycarbonate of this embodiment.

EMBODIMENT OF THE INVENTION Hereinafter, although the form (it is simply described as "this embodiment" for carrying out this invention) is demonstrated in detail, referring drawings, as needed, this invention is not limited to the following embodiment. . The present invention can be implemented in various modifications within the scope of the gist.

[Method for Producing Aromatic Polycarbonate]

In the manufacturing method of the aromatic polycarbonate of this embodiment,

Using the manufacturing apparatus in which the porous plate-shaped polymerizer with a support body and the scrubber are connected through the piping (A),

As a manufacturing method of aromatic polycarbonate which uses an aromatic dihydroxy compound and a diaryl carbonate as a raw material, and produces an aromatic polycarbonate,

The effluent containing the by-produced aromatic monohydroxy compound, unreacted aromatic dihydroxy compound, diaryl carbonate, and condensate accompanying them is, under reduced pressure, from the polymerizer through the pipe (A). With scrubber,

Using a scrubbing liquid in the scrubber to polymerize the aromatic polycarbonate by transesterification while condensing and dissolving the distillate,

The connection position of the said pipe (A) which connects the said polymerizer and the said scrubber shall be a linear part of the said polymerizer, and the lower half side of the said linear part.

(Raw material)

In the manufacturing method of the aromatic polycarbonate of this embodiment, an aromatic dihydroxy compound and a diaryl carbonate are used as a raw material.

<Aromatic Dihydroxy Compound>

An aromatic dihydroxy compound is a compound represented by a following formula.

HO-Ar-OH

(In the formula, Ar represents a divalent aromatic group.)

The divalent aromatic group Ar is preferably one represented by the following formula, for example.

-Ar ¹ -Y-Ar ^2-

(In the formula, Ar ¹ and Ar ² each independently represent a divalent carbocyclic or heterocyclic aromatic group having 5 to 70 carbon atoms, and Y represents a divalent alkane group having 1 to 30 carbon atoms.)

In the divalent aromatic groups Ar ¹ and Ar ² , at least one hydrogen atom does not affect the reaction, for example, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a phenyl group, or a phenoxy group , Vinyl group, cyano group, ester group, amide group, nitro group or the like may be substituted.

As a preferable specific example of a heterocyclic aromatic group, the aromatic group which has 1 to several ring formation nitrogen atom, oxygen atom, or a sulfur atom is mentioned.

The divalent aromatic groups Ar ¹ and Ar ² represent groups such as, for example, substituted or unsubstituted phenylene, substituted or unsubstituted naphthylene, substituted or unsubstituted biphenylene, substituted or unsubstituted pyridylene, and the like. .

Substituents here are as above-mentioned.

The divalent alkane group Y is an organic group represented by following formula (1), for example.

(In formula, R <^1> , R <^2> , R <^3> , R <^4> is respectively independently hydrogen, a C1-C10 alkyl group, a C1-C10 alkoxy group, a ring C5-C10 cycloalkyl group, ring constituent carbon number A 5 to 10 carbocyclic aromatic group and a C6 to 10 carbocyclic alkyl group are shown.

k represents an integer of 3 to 11, R ⁵ and R ⁶ are each selected individually for X, independently of each other, represent hydrogen or an alkyl group having 1 to 6 carbon atoms, and X represents carbon.

In addition, in R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ , other substituents such as halogen atoms and alkyl groups having 1 to 10 carbon atoms in a range in which one or more hydrogen atoms do not adversely affect the reaction. May be substituted with an alkoxy group having 1 to 10 carbon atoms, a phenyl group, a phenoxy group, a vinyl group, a cyano group, an ester group, an amide group, a nitro group, etc.)

As such a bivalent aromatic group Ar, what is represented by following formula (2) is mentioned, for example.

(Wherein R ⁷ and R ⁸ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 ring carbon atoms or a phenyl group, m and n Is an integer of 1 to 4, and when m is 2 to 4, each R ⁷ may be the same or different, and when n is 2 to 4, each R ⁸ may be the same or different.)

In addition, the divalent aromatic group Ar may be represented by the following formula.

-Ar ¹ -Z-Ar ^2-

Wherein Ar ¹ and Ar ² are the same as described above, and Z is a single bond or -O-, -CO-, -S-, -SO _2- , -SO-, -COO-, CON (R ¹ )- Divalent groups such as those provided that R ¹ is as defined above.)

As such a bivalent aromatic group Ar, what is represented by following formula (3) is mentioned, for example.

(Wherein R ⁷ , R ⁸ , m and n are as described above).

Moreover, as a specific example of bivalent aromatic group Ar, substituted or unsubstituted phenylene, substituted or unsubstituted naphthylene, substituted or unsubstituted pyridylene, etc. are mentioned.

The aromatic dihydroxy compound used in the present invention may be a single kind or two or more kinds. Bisphenol A is mentioned as a typical example of an aromatic dihydroxy compound.

<Diaryl carbonate>

Diaryl carbonate used in the present invention is represented by the following formula (4).

(In the formula, Ar ³ and Ar ⁴ each represent a monovalent aromatic group.)

Although Ar ³ and Ar ⁴ represent a monovalent carbocyclic or heterocyclic aromatic group, in this Ar ³ and Ar ⁴ , at least one hydrogen atom does not adversely affect the reaction of other substituents such as halogen atoms and carbon atoms 1 It may be substituted with an alkyl group of 10 to 10, an alkoxy group having 1 to 10 carbon atoms, a phenyl group, a phenoxy group, a vinyl group, a cyano group, an ester group, an amide group, a nitro group or the like.

Ar ³ and Ar ⁴ may be the same or different.

Representative examples of the monovalent aromatic groups Ar ³ and Ar ⁴ include a phenyl group, a naphthyl group, a biphenyl group, and a pyridyl group. These may be substituted by the 1 or more types of substituent mentioned above.

As preferable Ar <^3> and Ar <^4> , following formula (5) is mentioned, respectively.

Representative examples of the diaryl carbonate include those represented by the following general formula (6).

(Wherein R ⁹ and R ¹⁰ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 ring carbon atoms or a phenyl group, and p and q Is an integer of 1 to 5, and when p is 2 or more, each R ⁹ may be different from each other, and when q is 2 or more, each R ¹⁰ may be different from each other.)

Among these diphenyl carbonates, symmetrical diaryl carbonates such as lower alkyl substituted diphenyl carbonates such as unsubstituted diphenyl carbonate, ditryl carbonate and di-t-butylphenyl carbonate Although carbonate is preferred, diphenylcarbonate is particularly suitable, which is the diaryl carbonate of the simplest structure.

These diaryl carbonates may be used independently and may be used in combination of 2 or more type.

The use ratio (injection ratio) of the aromatic dihydroxy compound and the diaryl carbonate differs depending on the type of the aromatic dihydroxy compound and the diaryl carbonate used, the polymerization temperature, and other polymerization conditions. Reel carbonate is normally used in the ratio of 0.9-2.5 mol, preferably 0.9-2.0 mol, More preferably, 0.98-1.5 mol with respect to 1 mol of aromatic dihydroxy compounds.

The number average molecular weight of the aromatic polycarbonate obtained by the method of this invention is the range of 500-100000 normally, Preferably it is the range of 2000-30000.

In producing an aromatic polycarbonate by reacting an aromatic dihydroxy compound with a diaryl carbonate, the temperature of the reaction is usually selected in the range of 50 to 350 ° C, preferably 100 to 290 ° C.

As the reaction proceeds, the aromatic monohydroxy compound is by-produced. The aromatic monohydroxy compound by-produced in this invention is represented by following formula (7).

Wherein R ⁹ and p are as described above.

By removing this aromatic monohydroxy compound out of a reaction system under reduced pressure, the aromatic polycarbonate production | generation reaction rate (henceforth a polymerization rate) becomes high.

Preferable reaction pressures differ also depending on the kind, molecular weight, polymerization temperature, and the like of the aromatic polycarbonate to be produced. For example, when producing an aromatic polycarbonate from bisphenol A and diphenyl carbonate, the number average molecular weight If it is the range of 1000 or less, the range of 50 mmHg-normal pressure is preferable, If the number average molecular weight is the range of 1000-2000, the range of 3-50 mmHg is preferable, and if the number average molecular weight is the range of 2000 or more, 20 mmHg or less In particular, 10 mmHg or less is preferable, and 2 mmHg or less is more preferable.

In this invention, there is no restriction | limiting in particular in the vacuum apparatus which makes a polymerizer a pressure reduction, Various well-known vacuum pump can be used.

When the by-product aromatic monohydroxy compound is extracted out of the reaction system, unreacted aromatic dihydroxy compound, diaryl carbonate, and condensate are also simultaneously extracted out of the system from the polymerization reactor. The distillate in this invention represents the compound containing the by-product aromatic monohydroxy compound, the unreacted aromatic dihydroxy compound, and diaryl carbonate, and accompanying condensate.

The accompanying condensate refers to a low molecular weight aromatic polycarbonate vapor, a low molecular weight aromatic polycarbonate, an aromatic polycarbonate, or the like entrained in a by-produced aromatic monohydroxy compound or the like.

Low molecular weight aromatic polycarbonate generally shows an aromatic polycarbonate of about 300 to 3000 at a number average molecular weight.

The manufacturing method of the aromatic polycarbonate of this embodiment is a method of polycondensing by the transesterification reaction in the molten state from heating, in the presence or absence of a catalyst from the aromatic dihydroxy compound and the diaryl carbonate mentioned above. to be.

There is no restriction | limiting in particular in the polymerization machine in the first half of superposition | polymerization which manufactures the polymer with a number average molecular weight less than 2000 in the superposition | polymerization process of aromatic polycarbonate. On the other hand, in the latter half of the polymerization for producing a polymer having a molecular weight of 2000 or more, a porous plate-type polymerizer to polymerize while freely falling into the polymerizer, or a porous plate-type polymerizer with a support for allowing the polymer to melt and drop along the support to advance the polymerization In addition, the polymerizer which used these or single or combined is used.

In this embodiment, the porous plate type polymerizer with a support body is used.

The porous plate-type polymerizer with a support disperses the polymer in the porous plate, and causes polymerization to proceed by melting and dropping it in a foamed state along the support.

In the method for producing the aromatic polycarbonate of the present embodiment, when producing the aromatic polycarbonate, one or two or more polymerizers are used, but in the case of using two or more polymerizers, Plural polymerizers may be provided or only one group may be provided.

It is preferable to use the porous-plate type | mold polymerizer with a support body in the latter stage of superposition | polymerization in which polymerization pressure becomes low.

1, the schematic schematic diagram of the manufacturing apparatus which implements the manufacturing method of the aromatic polycarbonate of this embodiment is shown.

In the manufacturing apparatus of FIG. 1, the porous plate-shaped polymerizer 2 (hereinafter sometimes referred to simply as the polymerizer 2) with the support and the scrubber 11 are connected via a pipe (A) 10. Connected.

The porous plate-shaped polymerizer 2 with a support includes a polymer supply port 1, a porous plate 3 for dispersing a polymer, a porous plate 3, a polymerizer direct-drive part 5, and a tapered polymerizer bottom part. A support body 4 installed so as to extend downwardly from the porous plate 3 in a space surrounded by (6), an outlet 9 of aromatic polycarbonate provided at the bottom of the tapered polymerizer bottom 6, and the outlet ( The feed pump 8 of the aromatic polycarbonate connected to 9) is provided.

In the polymerizer 2, the polymer supplied from the polymer supply port 1 is dropped along the support 4 through the porous plate 3.

As a method of dropping a polymer, the method of extruding a polymer from the porous plate 3 by pressurizing using the method of dropping to a liquid head or its own weight, a pump, etc. are mentioned.

The number of pores in the porous plate 3 is not particularly limited and may vary depending on conditions such as reaction temperature and pressure, amount of catalyst, molecular weight range of the polymer to be polymerized, and the like, but is usually aromatic at 1000 kg / hr, for example. When preparing polycarbonates, 10 to 10 ⁵ holes are required.

After passing through the hole, the height of dropping the polymer along the support 4 is preferably 0.3 to 50 m, more preferably 0.5 to 30 m.

The flow rate of the polymer passing through the pores also varies depending on the molecular weight of the polymer, but is usually 10 ^-4 to 10 ⁴ litres / hr per hole, preferably 10 ^-2 to 10 ² litres / hr, more preferably Preferably from 0.05 to 50 liters / hr.

The time required for dropping the polymer along the support 4 is not particularly limited, but is usually in the range of 0.01 seconds to 10 hours.

The polymer is polymerized while falling along the support 4 to obtain an aromatic polycarbonate having a desired molecular weight.

The aromatic polycarbonate may be dropped into the liquid pooling unit 7 as it is, or may be blown into the liquid pooling unit 7 by a winder or the like.

The liquid level of the liquid pool 7 of the aromatic polycarbonate can be controlled in the tapered polymerizer bottom 6. Moreover, it is preferable to control so that liquid level may not rise up to the polymerizer linear motion part 5. As a result, the polymer flows out into the pipe (A) 10 connecting the polymerizer and the scrubber connected to the polymerizer linear motion part 5, or the residence time of the polymer in the polymerizer 2 is increased, resulting in foreign matter. Formation or yellowing can be prevented from occurring.

The scrubber 11 is a device having a function of dispersing a liquid in a gas as a plurality of fine droplets and / or a liquid film piece, and scrubs the liquid dispersed in the gas as a fine droplet and / or a liquid film piece by the scrubber 11. It is called liquid.

As the scrubber 11 which comprises a manufacturing apparatus, the well-known various scrubbers, such as a packed tower, an ejector, a rotary spray tower, and Venturi, can be used, for example (Incorporation of Chemical Industry Association; Maruzen Corporation). 5th edition of Chemical Engineering Handbook; 18 March 1988; P781; see Table 17.5).

As the scrubber 11, the fixed spray tower which has a heat exchanger is preferable, and the rotating spray tower which has a heat exchanger among the said well-known scrubbers is also preferable.

The scrubber 11 is demonstrated using FIG.

The outflow from the polymerizer 2 of the porous plate type with a support body is introduced into the scrubber 11 from the piping (A) 10 which connects the polymerizer 2 and the scrubber 11.

That is, an effluent containing an aromatic monohydroxy compound, an unreacted aromatic dihydroxy compound, a diaryl carbonate, and a condensate accompanying them in the process of producing an aromatic polycarbonate by a transesterification method. This is taken out by the scrubber 11.

In addition, the nozzle of the polymerizer 2 and the nozzle of the scrubber 11 may be connected directly, without going through piping, In this case, the site | part which the nozzle of the polymerizer 2 and the nozzle of the scrubber 11 connected was piping. It functions as (A) (10).

The scrubber 11 has a heat exchanger 13 inside which can be cooled by a refrigerant | coolant, and the scrubbing liquid is carried out from the spray hole 12 and the spray hole 14 which are upper and lower parts of this heat exchanger 13. It is supposed to be sprayed into the scrubber 11.

The scrubber 11 is connected with the vacuum pump 24 and the piping (E) 23, and the inside of the scrubber 11 containing the heat exchanger 13 is vacuumed by the said vacuum pump 24. It is supposed to be in a state. Thus, the effluent introduced into the scrubber 11 is condensed by heat exchange by contact with the scrubbing liquid and passage of the heat exchanger 13. Further, the effluent dissolves in the scrubbing liquid, and the effluent and the scrubbing liquid in which the effluent are dissolved are integrated into the bottom of the scrubber 11.

The scrubber 11 is connected to a feed pump 20 for transferring the scrubbing liquid through a pipe, and a filter 18 is provided in the pipe connecting the scrubber 11 and the feed pump 20. .

The scrubbing liquid 15 at the bottom of the scrubber 11 is a pipe (B) 17 for connecting the scrubber 11 and the filter 18, a pipe 18 for connecting the filter 18, and a filter and a transfer pump. (19) passes through the feed pump 20 of the scrubbing liquid, a part is circulated through the pipe (D) 22 connecting the feed pump 20 and the spray port of the scrubber 11, a part of the scrubbing liquid It is extracted to separate and recover the effluent from the outlet 21 of the.

The transfer pump 20 is normally installed at a position lower than the scrubber 11 from the viewpoint of securing the required suction head of the transfer pump. In addition, the wall surface of the heat exchanger 13 is always kept wet by the scrubbing liquid sprayed from the spray port 12, and prevents blockage by sticking of condensates. In order to keep the amount of the scrubbing liquid circulating in the system constant, the liquid amount extracted through the outlet 21 and the compound for the scrubbing liquid are made up from the supply port 16 thereof.

From the scrubbing liquid extracted from the discharge port 21, the compound for scrubbing liquid (for example, methylphenyl carbonate) may be collect | recovered using a distillation tower etc.

The manufacturing method of the aromatic polycarbonate of this embodiment improves the scrubber 11 and the scrubber periphery piping 10, 17, 19, 22, and wash | cleans the scrubber 11 during the shutdown of a manufacturing apparatus, Moreover, using specific scrubbing liquid as a preferable form, it is a manufacturing method of aromatic polycarbonate suitable for production on an industrial scale.

The peripheral piping of the scrubber is the piping (A) 10 which connects the polymerizer 2 and the scrubber 11, the piping (B) 17 which connects the scrubber 11, and the filter 18, and the filter 18. ) Means a pipe (C) (19) for connecting the feed pump 20 of the scrubbing liquid, and a pipe (D) (22) for connecting the spray port of the scrubbing pump (20) and the scrubbing liquid feed pump (20). .

Manufacturing on an industrial scale means producing at least 1000 kg of aromatic polycarbonate per hr.

The connection position of the piping (A) 10 which connects the polymerizer 2 and the scrubber 11 is the linear motion part 5 of a polymerization machine, and needs to be the lower half side of the said linear motion part. Preferably it is the lower 1/3 side of a linear motion part, More preferably, it is the lower 1/4 side of a linear motion part.

In the porous plate-shaped polymerizer 2 with a support, since the polymer is advanced by melting and falling the polymer along the support 4, the lower side is more spilled than the upper side of the linear part 5 of the polymerizer. There is little amount of the unreacted aromatic dihydroxy compound and diaryl carbonate, low molecular weight aromatic polycarbonate vapor, and low molecular weight aromatic polycarbonate. Therefore, by this method, the quantity of the outflow which flows into the scrubber 11 from piping (A) 10 can be reduced.

The inner diameter of the linear motion portion of the scrubber 11 is preferably 200 to 2500 mm. More preferably, it is 500-1500 mm, More preferably, it is 600-1300 mm.

Since the inner diameter of the linear part of the scrubber 11 is 200 mm or more, the pressure loss of the scrubber 11 can be suppressed. By being 2500 mm or less, increase of equipment cost can be suppressed and installation space can be reduced.

The inner diameter of the pipe (A) 10 which connects the polymerization reactor 2 and the scrubber 11 is 0.5 times or more of the inner diameter of the linear part of the scrubber 11 from the viewpoint of preventing clogging due to the stuck outflow. It is preferable. More preferably, it is 0.55 times or more, More preferably, it is 0.6 times or more.

In addition, it is preferable to heat the piping (A) 10 which connects the polymerization reactor 2 and the scrubber 11 to 100-300 degreeC from a viewpoint of preventing the condensation and solidification of an outflow. More preferably, it is 150-300 degreeC, More preferably, it is 200-300 degreeC.

Heating can be performed using the trace of a thermal medium, a jacket, etc., and it can control to the said temperature range by adjusting these set temperatures.

Further, from the viewpoint of preventing sticking of the effluent, downward inclination of 1/100 or more in the direction from the polymerizer 2 to the scrubber is connected to the pipe (A) 10 connecting the polymerizer 2 and the scrubber 11. It is preferable to form. More preferably, it forms a downward slope of 1/50 or more, more preferably 1/30 or more.

By preventing the condensation and solidification of the inner wall due to condensation of the effluent, clogging of the nozzle and the pipe can be reliably prevented.

Moreover, in the manufacturing apparatus of aromatic polycarbonate, the said scrubber 11 is connected with the feed pump 20 which transfers the scrubbing liquid through piping, and the said scrubber 11 and the feed pump 20 are connected. In the pipe connecting the pipes, the filter 18 having a capacity of 1 to 200 liters in which 10 to 200 mesh elements are inserted on the suction side of the feed pump 20 of the scrubbing liquid is removed. It is preferable from a viewpoint. More preferably, the capacity is 1 to 150 liters, and more preferably 1 to 100 liters. Moreover, more preferable mesh size is 10-150 mesh, More preferably, it is 10-100 mesh.

When the element is 10 mesh or more, the exchange frequency of the element can be suppressed. In addition, since the element is 200 mesh or less, it is possible to prevent the solidified effluent from passing through the element.

On the other hand, when the capacity of the filter 18 is 1 liter or more, the replacement frequency of the element can be suppressed. When the capacity is 200 liters or less, the equipment cost can be reduced and the installation space can be suppressed.

Since the scrubbing liquid is circulated at a negative pressure, and the filter 18 becomes larger in pressure loss when clogging of the effluent occurs, the scrubbing liquid is in an environment where the scrubbing liquid tends to boil on the suction side of the transfer pump 20.

Boiling of the scrubbing liquid on the suction side of the transfer pump 20 causes cavitation of the transfer pump 20.

Therefore, the piping (C) 19 which connects the filter 18 and the transfer pump 20 is installed horizontally at the same height as the transfer pump 20, and the transfer pump 20 is installed in the piping (C) 19. It is preferable to apply a pressure equal to a pressure appropriate to the effective suction head of the step from the viewpoint of preventing boiling of the scrubbing liquid.

For example, when the filter 18 is installed at a position higher than the transfer pump 20, the pressure of a portion of the pipe (C) 19 at a position higher than the transfer pump 20 is effective at the effective suction head of the transfer pump 20. Since the pressure is lower than the appropriate pressure, the scrubbing liquid tends to boil when clogging occurs in the filter 18, which is not preferable.

The scrubber 11 and / or the piping B are formed in the piping (B) 17 which connects the scrubber 11 and the filter 18 to the downward inclination of 1/100 or more in the direction toward the filter 18. Since the effluent condensed and solidified in (17) becomes hard to adhere to the inner wall of piping (B) 17, it is preferable from a viewpoint of preventing the blockage by the effluent.

More preferably, it forms a downward slope of 1/50 or more, more preferably 1/30 or more.

Piping (E) 23 which connects the scrubber 11 and the vacuum pump 24 is directed toward the vertical upper direction from the connection part of the scrubber 11, and thereafter, it is 1/200 or more downward toward the vacuum pump 24 It is preferable to have the inclination from the viewpoint of preventing the condensation of the condensation and the solidified effluent in the pipe 23.

More preferably, it has a downward slope of 1/150 or more, More preferably, it is 1/100 or more.

In addition, the piping (E) 23 which connects the scrubber 11 and the vacuum pump 24 is preferable to heat at 100-250 degreeC from a viewpoint of preventing the condensation and solidification of an outflow. More preferably, it is 110-230 degreeC, More preferably, it is 120-210 degreeC.

In addition, it is also preferable to supply and purge 0.5 to 200 N liter / hr of inert gas such as nitrogen and the like from the viewpoint of preventing condensation and solidification of the effluent. More preferably, it is 0.5-150 N liter / hr, More preferably, it is 0.5-100 N liter / hr.

By performing the above-described construction, the scrubber 11, the peripheral pipes (A) 10, the pipes (B) 17, the pipes (C) 19, and the pipes (D) 22 of the scrubber 11 are ), And the blockage due to sticking and sticking of the effluent in the pipe (E) 23 can be effectively prevented, but if the production of the aromatic polycarbonate is continued for a long time, the effluent may be stuck. If such sticking is left uncovered, effluent accumulates, and in the worst case, there is a risk of clogging.

Therefore, in the manufacturing method of the aromatic polycarbonate of this embodiment, the scrubber 11, the piping (B) 17 which connects a scrubber, and a filter during the operation stop of a manufacturing apparatus, and the filter and The steam is vented to the steam traces provided in the pipe (C) 19 for connecting the feed pump of the scrubbing liquid and the pipe (D) 22 for connecting the spray port of the scrubber with the feed pump of the scrubbing liquid, and the scrubber 11 It is preferable to wash the filter 18 and the pipes (B) to (D) with an aromatic monohydroxy compound in full liquid.

In addition, it is preferable not to vent steam to these steam traces during the operation of the manufacturing apparatus from the viewpoint of condensing the effluent in the scrubber 11 during the manufacturing process.

Moreover, in order to wash | clean the piping (A) 10 which connects the polymerization reactor 2 and the scrubber 11, it is preferable to also wash the polymerization reactor 2 of a support plate type with support simultaneously with an aromatic monohydroxy compound. .

It is preferable that a scrubbing liquid contains the alkylaryl carbonate represented by following formula (8) as a compound for scrubbing liquid.

In formula, R <^10> represents a C1-C10 alkyl group.

Ar ⁵ represents a monovalent aromatic group.

Ar ⁵ represents a monovalent carbocyclic or heterocyclic aromatic group, but in Ar ⁵ , one or more hydrogen atoms do not adversely affect the reaction, for example, a halogen atom, an alkyl group having 1 to 10 carbon atoms, and a carbon atom having 1 to 5 carbon atoms. 10 may be substituted with an alkoxy group, a phenyl group, a phenoxy group, a vinyl group, a cyano group, an ester group, an amide group, a nitro group, or the like.

Although it is not limited to the following as alkylaryl carbonate, For example, ethylphenyl carbonate, n-propylphenyl carbonate, i-propylphenyl carbonate, n-butylphenyl carbonate, i-butyl Phenyl carbonate and t-butylphenyl carbonate are mentioned as a preferable thing. More preferably, it is methylphenyl carbonate. This is because (a) the boiling point is high, so that the load on the vacuum apparatus can be reduced, and (b) the melting point is low, and solidification is performed in the peripheral piping of the nozzle, the scrubber, and the scrubber which extracts the effluent from the porous plate-type polymerization reactor with the support. (C) Since the effluent can be dissolved and the likelihood of the effluent solidifying can be reduced at the point where the scrubbing liquid comes into contact with, since it is unlikely to be separated from the effluent. It is because it is easy to recycle | reuse as an intermediate at the time of manufacturing diaryl carbonate from (e) aromatic monohydroxy compound since it is easy and a high recovery rate.

EXAMPLE

EMBODIMENT OF THE INVENTION Hereinafter, although this embodiment is concretely demonstrated to a specific example and a comparative example, this embodiment is not limited to a following example.

EXAMPLE 1

Using the manufacturing apparatus shown in FIG. 1, 5000 kg of aromatic polycarbonate was produced per hour.

The manufacturing apparatus of FIG. 1 is equipped with the porous plate type | mold polymerizer 2 and the scrubber 11 with a support body.

The porous plate-shaped polymerizer 2 with a support is provided with a porous plate 3 having 2000 holes having a hole diameter of 4 mm. The support body 4 is the wire made from SUS316L of 2 mm diameter perpendicularly from the center of each hole, is lined up to the liquid pool part 7 of the lower part of the polymerization vessel, and the height which a polymer falls was 8 m.

Bisphenol A as an aromatic dihydroxy compound and diphenyl carbonate (to bisphenol A molar ratio 1.13) as a diaryl carbonate were respectively combined in a polymer raw material combining process (not shown), and the reaction mixture obtained was The polymer of the number average molecular weight 5000 was continuously obtained by superposing | polymerizing in a prepolymerization process (not shown) and a 1st polymerization process (not shown).

The polymer of the number average molecular weight 5000 obtained by the said 1st superposition | polymerization process was introduce | transduced into the inside of the porous plate type | mold polymerizer 2 with a support body through the porous plate 3 from the polymer supply port 1.

The polymerization was carried out while the polymer obtained by the first polymerization step was dropped inside the polymerization reactor along the support 4.

0.5 hour residence time while reaching the tapered type | mold polymerizer bottom part 6 and maintaining the liquid level of the bottom part of the polymerizer 2 the aromatic polycarbonate 7 which became number average molecular weight 11000 It discharged from the discharge port 9 by the feed pump 8, controlling so that it might become so.

The operating conditions of the polymerization reactor 2 were made into the temperature of 270 degreeC, and the pressure of 0.8 mmHg.

The effluent containing the aromatic monohydroxy compound, the unreacted aromatic dihydroxy compound, the diaryl carbonate, and the accompanying condensate which flowed out from the polymerization reactor 2 is lower side of the linear part 5 of the polymerization reactor. It introduce | transduced into the scrubber 11 from the piping (A) 10 which connects the polymerizer 2 and the scrubber 11 connected to (except on the welding line).

The inner diameter of the pipe (A) 10 was 750 mm, which corresponds to 0.75 times the inner diameter of the straight part of the scrubber 11 of 1000 mm.

In addition, 1/5 downward inclination was formed in the said pipe (A) 10 toward the scrubber 11.

Moreover, 270 degreeC heat medium oil was made to flow through the jacket of the said piping (A) (10), and it heated.

The scrubber 11 is supplied with methylphenyl carbonate from the supply port 16, and the scrubbing liquid containing the effluent and methylphenyl carbonate is circulated through the pipe (D) 22 by the transfer pump 20. And sprayed into the scrubber 11 from the spray holes 12 and 14.

The concentration of methylphenyl carbonate in the scrubbing liquid was 60 mass%.

The scrubber 11 is connected to the transfer pump 20 via a pipe, and a capacity of 50 mesh elements inserted into the pipe at the same height as the transfer pump 20 on the suction side of the transfer pump 20. 10 liters of filters 18 were installed.

Piping (B) 17 which connects the scrubber 11 and the filter 18 once lowered from the scrubber 11 in the vertical direction, and formed 1/5 downward inclination toward the filter 18.

The scrubber 11 is connected to the vacuum pump 24 via the pipe (E) 23, and the pipe (E) 23 which connects the scrubber and the vacuum pump to the effluent not condensed in the scrubber 11. ) Was introduced into the vacuum pump 24 via.

The pipe (E) 23 faces the vertical upper direction from the scrubber 11 connection part, and has a 1/100 downward inclination toward the vacuum pump 24 after that.

Moreover, the steam of 140 degreeC was vented to the steam trace of piping (E) 23, and it heated. Further, 20 N liters / hr of nitrogen was purged in the pipe (E) 23.

The scrubber 11 was controlled at the gas phase temperature of 15 degreeC.

The effluent condensed in the scrubber 11 was discharged from the outlet 21 together with methylphenyl carbonate.

The discharged effluent and methylphenyl carbonate are fed to a packed column distillation column (not shown), and the by-product monohydroxy compound, methylphenyl carbonate, unreacted diaryl carbonate, unreacted dihydroxy compound and condensation It separated into four components of water and collect | recovered each.

The recovered methylphenyl carbonate was made into the scrubber 11 from the supply port 16 and reused.

Aromatic polycarbonates were prepared continuously for 16000 hours under the conditions described above.

As a result, the polymerization reactor 2 was operated at a constant pressure, and it was possible to continuously and stably produce an aromatic polycarbonate having a number average molecular weight of 11000.

Outflow from the scrubber 11, the peripheral pipe (A) 10, the pipe (B) 17, the pipe (C) 19, the pipe (D) 22 and the pipe (E) 23 of the scrubber Occlusion due to water fixation did not occur.

In addition, after completion | finish of continuous manufacture, the scrubber 11, the piping (B) 17 which connects a scrubber and a filter, the filter 18, the piping (C) 19 which connects a feed pump of a filter and a scrubbing liquid, A steam trace of 140 ° C. is passed through a steam trace provided to a pipe (D) 22 or the like that connects the scrubbing pump and the spray port to the scrubbing liquid, and further includes a scrubber 11, a filter 18, a pipe (B) 17, The scrubber 11 was wash | cleaned for 24 hours by making piping (C) (19) and piping (D) 22 into fully liquid state with an aromatic monohydroxy compound.

EXAMPLE 2

The inner diameter of the pipe 10 connecting the polymerization reactor 2 and the scrubber 11 was set to 0.33 times the inner diameter of the linear motion portion of the scrubber 11, and the pipe 10 was not heated by the heat medium. In addition, the inclination was not formed in the piping 10, and it was leveled.

Other conditions produced the aromatic polycarbonate similarly to Example 1.

As a result, the polymerizer 2 was operated at a constant pressure for 4000hr from the start of operation, and it was possible to continuously and stably produce an aromatic polycarbonate having a number average molecular weight of 11000.

After 4000hr elapsed, since the pressure of the polymerization reactor 2 started to be slightly disturbed, manufacture was stopped.

As a result of the release check, it can be seen that a small amount of effluent is fixed in the pipe 10.

EXAMPLE 3

The filter 18 was not installed on the suction side of the feed pump 20 of the scrubbing liquid.

Moreover, it did not incline the piping 17 and 19 from the scrubber 11 to the feed pump 20, but was made horizontal.

Other conditions produced the aromatic polycarbonate similarly to Example 1.

As a result, the polymerizer 2 was operated at a constant pressure for 8000 hrs from the start of operation, and it was possible to continuously and stably produce an aromatic polycarbonate having a number average molecular weight of 11000.

After 8000 hr had elapsed, the pressure of the polymerization reactor 2 began to be slightly disturbed, so the production was stopped.

As a result of the release check, it can be seen that a small amount of effluent is fixed in the spray holes 12 and 14.

EXAMPLE 4

The heating by the heat medium of the piping 23 which connects the scrubber 11 and the vacuum pump 24 was not performed. In addition, nitrogen was not supplied to the piping 23. In addition, it did not form a slope in the said piping 23, and was made horizontal.

Other conditions produced the aromatic polycarbonate similarly to Example 1.

As a result, the polymerizer 2 was operated at a constant pressure for 8000 hrs from the start of operation, and it was possible to continuously and stably produce an aromatic polycarbonate having a number average molecular weight of 11000.

After 8000 hr had elapsed, the pressure of the polymerization reactor 2 began to be slightly disturbed, so the production was stopped.

As a result of the release check, it can be seen that a small amount of effluent is fixed in the pipe 23.

[Example 5]

After completion of the preparation over 16000 hr, unlike Example 1, the scrubber was not washed with the aromatic monohydroxy compound. Thereafter, production of the aromatic polycarbonate was started again.

After a while after the resumption of production, the pressure of the polymerization reactor 2 began to be slightly disturbed, so the production was stopped.

As a result of the release check, it can be seen that a small amount of effluent is fixed in the spray holes 12 and 14.

EXAMPLE 6

Tetraethylene glycol was used as a scrubbing compound for the scrubber 11. The other conditions produced aromatic polycarbonate similarly to Example 1.

As a result, the polymerizer 2 was operated at a constant pressure for 8000 hrs from the start of operation, and it was possible to continuously and stably produce an aromatic polycarbonate having a number average molecular weight of 11000.

After 8000 hr had elapsed, clogging occurred in the filter 18, so that the elements of the filter 18 were replaced.

After that, since clogging of the filter 18 occurred about once a month, the production was stopped.

[Comparative Example 1]

The pipe 10 connecting the polymerizer 2 and the scrubber 11 is connected to the upper end of the linear part of the polymerizer 2 (except on the welding line), and the effluent is removed from the pipe 10 by the scrubber ( 11) was extracted.

Other conditions were the same as that of [Example 1], and produced aromatic polycarbonate.

As a result, after 40 hours passed, the pressure of the polymerization reactor 2 began to be disturbed, and manufacturing was impossible.

As a result of the release check, it can be seen that the pipe 10 is blocked by the solidified effluent.

INDUSTRIAL APPLICABILITY The present invention has industrial applicability as a method for producing aromatic polycarbonate which can stably produce aromatic polycarbonate on an industrial scale for a long time.

1: polymer feed port
2: porous plate type polymerizer with support
3: perforated plate
4: support
5: linear part of polymerizer
6: tapered polymerizer bottom
7: Liquid pool of aromatic polycarbonate
8: transfer pump of aromatic polycarbonate
9: Outlet of Aromatic Polycarbonate
10: Piping for connecting the polymerizer and the scrubber (A)
11: scrubber
12, 14: spray hole
13: heat exchanger
15: scrubbing liquid at the bottom of the scrubber
16: Supply port of compound for scrubbing liquid
17: Piping for connecting scrubber and filter (B)
18: filter
19: Piping for connecting the filter and the transfer pump of the scrubbing liquid (C)
20: transfer pump of scrubbing liquid
21: outlet of the scrubbing liquid
22: pipe (D) connecting the pump and the spray port of the scrubbing liquid
23: Pipe for connecting the scrubber and the vacuum pump (E)
24: vacuum pump

Claims (10)

Using a manufacturing apparatus in which the porous plate-shaped polymerizer with scaffold and the scrubber are connected through a pipe (A),
As a manufacturing method of aromatic polycarbonate which uses an aromatic dihydroxy compound and a diaryl carbonate as a raw material, and produces an aromatic polycarbonate,
The effluent containing the by-produced aromatic monohydroxy compound, unreacted aromatic dihydroxy compound, diaryl carbonate, and condensate accompanying them is scrubbed from the polymerizer through the pipe (A) under reduced pressure. To be extracted,
Using a scrubbing liquid in the scrubber to polymerize the aromatic polycarbonate by transesterification while condensing and dissolving the effluent,
The connection position of the said pipe (A) which connects the said polymerizer and the said scrubber is a linear part of the said polymerizer, and is the lower half side of the said linear part,
Process for the production of aromatic polycarbonates. The inner diameter of the linear body of the scrubber is 200 to 2500mm,
The internal diameter of the said piping (A) which connects the said polymerizer and the said scrubber is the manufacturing method of aromatic polycarbonate which is 0.5 times or more of the internal diameter of the linear part of the scrubber. The manufacturing method of the aromatic polycarbonate of Claim 1 or 2 which heats the said piping (A) which connects the said polymerizer and the said scrubber to 100-300 degreeC. The piping (A) of Claim 1 or 2 which connects the said polymerizer and the said scrubber,
A downward slope of 1/100 or more is formed in a direction from the polymerizer toward the scrubber,
Process for the production of aromatic polycarbonates. The said scrubber is connected with the transfer pump which transfers a scrubbing liquid, and piping through the piping of Claim 1 or 2,
The pipe which connects the said scrubber and the said transfer pump is provided with the filter,
The filter is a suction side of the transfer pump, is installed at the same height as the transfer pump,
The filter is a filter having a capacity of 1 to 200 liters with an element of 10 to 200 mesh inserted therein,
Process for the production of aromatic polycarbonates. The pipe (B) according to claim 5, wherein the scrubber and the filter are connected to each other.
The manufacturing method of the aromatic polycarbonate in which the downward inclination of 1/100 or more is formed in the direction toward the said filter. The said scrubber is connected with the vacuum pump through piping (E),
The piping (E) which connects the said scrubber and a vacuum pump is heated to 100-250 degreeC, and the manufacturing method of aromatic polycarbonate which purges with 0.5-200 N liter / hr of inert gas. The pipe (E) for connecting the scrubber and the vacuum pump according to claim 7,
The manufacturing method of the aromatic polycarbonate which faces a vertical upward direction from the said scrubber connection part, and has a downward inclination of 1/200 or more toward the said vacuum pump after that. The scrubbing liquid transfer pump and the spray port disposed in the scrubber are connected via a pipe (D).
During the shutdown of the manufacturing apparatus,
The scrubber,
Piping (B) for connecting the scrubber and the filter,
The filter,
Piping (C) for connecting the filter and the transfer pump of the scrubbing liquid,
Pipe (D) connecting the scrubbing liquid transfer pump and the spray port
Venting steam to
In addition, the scrubber, the filter and the pipes (B) to (D) are washed with liquid aromatic monohydroxy compounds in full liquid,
Process for the production of aromatic polycarbonates. The process for producing an aromatic polycarbonate according to claim 1 or 2, wherein the scrubbing liquid contains an alkylaryl carbonate.

Images