JP2003183380A - Method for manufacturing polycarbonate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a polycarbonate excellent in quality by using a transesterification method having no environmental issue and excellent in economy. <P>SOLUTION: In the method where an aromatic dihydroxy compound and a diester carbonate are transesterified in the presence of a catalyst to manufacture an aromatic polycarbonate, a reactor body, a mixture for reaction receiving pipe section, a by- product discharge pipe section and a polymerization mixture extraction pipe section are each covered with a heating medium jacket, and when for the temperature of at least one reaction unit, the internal temperature of the reactor body is set at t2 degree C, the internal temperature of a device of the mixture for reaction installed upstream is set at t2 degree C, and the internal temperature of a device of the polymerization mixtures installed downstream is set at t3 degree C, temperature of a heating medium inflowing in a jacket of the by-product discharge pipe section is set at a temperature between t1+5 degree C and t1+35 degree C, temperature of the heating medium inflowing in a jacket of the mixture for reaction received pipe section is set at a temperature between t2 and t1, and temperature of the heating medium inflowing in a jacket of the polymerization mixture extraction section is set at a temperature between t1 and t3. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an aromatic polycarbonate, and more specifically,
The present invention relates to a method for stably and continuously producing an aromatic polycarbonate having an excellent hue and a low content of foreign matter.

[0002]

2. Description of the Related Art Aromatic polycarbonates are widely used because they are excellent in mechanical properties such as impact resistance, heat resistance and transparency. Examples of the method for producing such an aromatic polycarbonate include a method of directly reacting an aromatic dihydroxy compound such as bisphenol with phosgene (interfacial method), or an aromatic dihydroxy compound such as bisphenol and an aromatic carbonic acid diester such as diphenyl carbonate. A method is known in which a transesterification reaction (melting method) is performed in a molten state.

Of these production methods, the method for producing a polycarbonate by transesterification of an aromatic dihydroxy compound and a carbonic acid diester does not use toxic phosgene and does not use methylene chloride as a solvent. Is an environmentally friendly manufacturing method, and
This is a manufacturing method that has been attracting attention because it can be manufactured at low cost. However, the method for producing a polycarbonate by a transesterification reaction has a problem that it is inferior in quality of the obtained polycarbonate, particularly in terms of hue and foreign matter content, as compared with the interfacial method.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for producing a polycarbonate of good quality by using a transesterification method which has no environmental problems and is excellent in economic efficiency.

[0005]

That is, the present invention comprises the techniques described below.

[0006] The reaction tank main body, a pipe portion for receiving a reaction mixture from an apparatus installed upstream and adjacent to the reaction tank main body, for connecting the reaction tank main body and the condenser to discharge the by-product vapor Using a facility in which at least two reaction units each including a pipe portion and a pipe portion for supplying the polymerization mixture generated in the reaction tank main body to an apparatus installed adjacently downstream are installed in series, In the method for producing an aromatic polycarbonate by transesterifying a dihydroxy compound and a carbonic acid diester in the presence of a catalyst, the reaction tank body, a reaction mixture receiving pipe part, a byproduct discharge pipe part, and a polymerization mixture extracting pipe part are each heated. While covering with a medium jacket, at least one reaction unit temperature is t1 ° C. inside the reaction tank body, and t2 is inside temperature of the apparatus installed upstream.
℃, when the internal temperature of the equipment installed downstream is t3 ℃, the temperature of the heat medium flowing into the jacket of the by-product discharge piping is t1 +
The temperature between 5 ° C and t1 + 35 ° C, the temperature of the heat medium flowing into the jacket of the reactant receiving pipe section between t2 and t1, and the temperature of the heat medium flowing into the jacket of the polymerization mixture withdrawing pipe section Is a temperature between t1 and t3, and the temperature difference between the heat medium temperature flowing into each jacket of the reaction unit and the heat medium temperature flowing out from each jacket is 2
A method for producing an aromatic polycarbonate, which is characterized in that the temperature is within 0 ° C. Further, a) the heating medium flowing into each jacket of the reaction unit and the heating medium flowing out are connected by a pipe, thereby making it independent for each temperature level. A circulation system is provided, and b) a pump for circulation is installed in each circulation system, and when the temperature of the heat medium flowing out from the jacket is higher than the temperature of the heat medium flowing in, the heat medium flowing out is cooled and flows into the jacket. A cooler is installed to enter the circulation pump at a temperature lower than the heat medium temperature, and c) a thermometer for measuring the heat medium temperature at the outlet side of the heat medium circulation pump and the measured temperature. A mechanism for injecting a high-temperature heat medium to maintain the temperature of the heat medium flowing into the jacket is installed, and d) an amount of the heat medium corresponding to the injected high-temperature heat medium is circulated at the inlet side of the heat medium pump. By installing a mechanism to discharge outside, A process for producing an aromatic polycarbonate, characterized in that for controlling the temperature of the heating medium flowing into the socket.

The aromatic polycarbonate referred to in the present invention is obtained by subjecting an aromatic dihydroxy compound, which is a main component, and a carbonic acid ester to melt polycondensation in the presence of a transesterification catalyst comprising a basic nitrogen compound and an alkali metal compound. It is an aromatic polycarbonate.

Specific examples of such aromatic dihydroxy compounds include bis (4-hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) propane and 2,2-bis (4-hydroxy-3). -Methylphenyl) propane, 4,4-bis (4-hydroxyphenyl) heptane, 2,2-bis (4-hydroxy-3,5
-Dichlorophenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, bis (4-hydroxyphenyl) oxide, bis (3,5
-Dichloro-4-hydroxyphenyl) oxide,
p, p'-dihydroxydiphenyl, 3,3'-dichloro-4,4'-dihydroxydiphenyl, bis (hydroxyphenyl) sulfone, resorcinol, hydroquinone, 1,4-dihydroxy-2,5-dichlorobenzene, 1,4 -Dihydroxy-3-methylbenzene, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfoxide and the like can be mentioned, with 2,2-bis (4-hydroxyphenyl) propane being particularly preferable.

Specific examples of the carbonic acid diester include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate and bis (diphenyl).
Carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate and the like are used, but diphenyl carbonate is particularly preferable.

Further, if necessary, the polycarbonate of the present invention may contain, as aliphatic diols, ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 1,10-decanediol and the like. Examples of dicarboxylic acids include succinic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, cyclohexanecarboxylic acid, and tereflutaic acid; oxyacids such as lactic acid, P-hydroxybenzoic acid, and 6-hydroxy-2-naphthoic acid. It may contain an acid or the like.

The catalyst used in the present invention is not particularly limited, but a transesterification catalyst composed of a basic nitrogen compound and an alkali metal compound and / or an alkaline earth metal compound can be used.

The alkali metal and / or alkaline earth metal compound used in the present invention is not particularly limited as long as it does not reduce the hue of the aromatic polycarbonate obtained, and various known compounds can be used. it can.

Examples of alkali metal compounds used as catalysts include alkali metal hydroxides, hydrogen carbonates, carbonates, acetates, nitrates, nitrites, sulfites, cyanates, thiocyanates and stearates. , Borohydride salts, benzoate salts, phosphohydrides, bisphenols, phenol salts and the like.

As specific examples, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate, sodium carbonate,
Potassium carbonate, lithium carbonate, sodium acetate, potassium acetate, lithium acetate, sodium nitrate, potassium nitrate, lithium nitrate, sodium nitrite, potassium nitrite, lithium nitrite, sodium sulfite, potassium sulfite, lithium sulfite, sodium cyanate, potassium cyanate , Lithium cyanate, sodium thiocyanate,
Potassium thiocyanate, lithium thiocyanate, sodium stearate, potassium stearate, lithium stearate, sodium borohydride, potassium borohydride, lithium borohydride, sodium phenyl borate, sodium benzoate, potassium benzoate, benzoin Examples thereof include lithium acid salt, disodium hydrogen phosphate, dipotassium hydrogen phosphate, dilithium hydrogen phosphate, disodium salt of bisphenol A, dipotassium salt, dilithium salt, sodium salt of potassium, potassium salt and lithium salt.

Examples of the alkaline earth metal compound used as a catalyst include hydroxides, hydrogencarbonates, carbonates, acetates, nitrates, nitrites, sulfites, cyanates and thiocyanates of alkaline earth metals. , Stearate,
Examples thereof include benzoate, bisphenol, and phenol salt.

As specific examples, calcium hydroxide, barium hydroxide, strontium hydroxide, calcium hydrogen carbonate, barium hydrogen carbonate, strontium hydrogen carbonate, calcium carbonate, barium carbonate, strontium carbonate, calcium acetate, barium acetate, strontium acetate, Calcium nitrate, barium nitrate, strontium nitrate, calcium nitrite, barium nitrite, strontium nitrite, calcium sulfite, barium sulfite, strontium sulfite, calcium cyanate, barium cyanate, strontium cyanate, calcium thiocyanate, barium thiocyanate, Strontium thiocyanate, calcium stearate, barium stearate, strontium stearate, calcium borohydride, barium borohydride, water Boron strontium, calcium benzoate, barium benzoate, strontium benzoate, calcium salts of bisphenol A, a barium salt,
Examples thereof include strontium salt, calcium salt of phenol, barium salt, and strontium salt.

In the present invention, if desired, (a) an alkali metal salt of an ate complex of an element of Group 14 of the periodic table or (b) an oxo acid of an element of Group 14 of the periodic table, as an alkali metal compound of the catalyst. Alkali metal salts of can be used. Here, the elements of Group 14 of the periodic table refer to silicon, germanium, and tin.

(A) Alkali metal salts of ate complexes of Group 14 elements of the periodic table include those described in JP-A-7-268091, specifically, a compound of germanium (Ge); NaGe (OMe) ₅ , NaGe
(OEt) ₃ , NaGe (OPr) ₅ , NaGe (OB
u) ₅ , NaGe (OPh) ₅ , LiGe (OMe) ₅ ,
Examples thereof include LiGe (OBu) ₅ and LiGe (OPh) ₅ .

The compound of tin (Sn) is NaSn.
(OMe) ₃ , NaSn (OMe) ₂ (OEt), NaS
_{n (OPr) 3, NaSn (} O-n-C 6 H 13) 3, Na
Sn (OMe) ₅ , NaSn (OEt) ₅ , NaSn (O
_{Bu) 5, NaSn (O-} n-C 12 H 25) 5, NaSn
(OEt), NaSn (OPh) ₅ , NaSnBu ₂ (O
Me) ₃ can be mentioned.

Examples of the alkali metal salt of oxo acid of group 14 element of the periodic table (b) include silicic acid (sili)
Cic acid alkali metal salt, stannic acid (sta
nic acid) alkali metal salt, germanium (II) acid (germanous acid) alkali metal salt, germanium (IV) acid (germanic)
Acidic alkali metal salts may be mentioned as preferred ones.

The alkali metal salt of silicic acid is, for example, an acidic or neutral alkali metal salt of monosilicic acid or its condensate, and examples thereof include monosodium orthosilicate, disodium orthosilicate, orthosilicic acid. Mention may be made of trisodium and tetrasodium orthosilicate.

The alkali metal salt of stannic acid is, for example, an acidic or neutral alkali metal salt of monostannic acid or its condensate, and examples thereof include disodium monostannate (Na ₂ SnO ₃ .X
_{H 2 O, X = 0~5)} , mention may be made of Monosuzu acid tetrasodium salt (Na ₄ SnO _4).

Germanium (II) acid (germano)
The alkali metal salt of (us acid) is, for example, an acidic or neutral alkali metal salt of monogermanic acid or a condensate thereof, and examples thereof include monosodium germanate (NaHGeO ₂ ).

Germanium (IV) acid (germani)
The alkali metal salt of c acid) is, for example, an acidic or neutral alkali metal salt of monogermanium (IV) acid or a condensation product thereof, and examples thereof include orthogermanate monolithic acid (LiH ₃ GeO ₄ ) orthogermanate. Disodium salt, orthogermanic acid tetrasodium salt, digermanic acid disodium salt (Na
₂ Ge ₂ O ₅ ), tetragermanic acid disodium salt (Na ₂ Ge ₄ O ₉ ) and pentagermanic acid disodium salt (Na ₂ Ge ₅ O ₁₁ ).

The alkali metal compound or the alkaline earth metal compound as the catalyst is 1 × 10 ^{-8 to} 5 × 10 ^-5 equivalents of the alkali metal element or the alkaline earth metal element in the catalyst per mol of the aromatic diol compound. It is preferably used when A more preferable ratio is a ratio of 5 × 10 ⁻⁷ to 1 × 10 ⁻⁵ equivalent based on the same standard.

When the amount of the alkali metal element or the amount of the alkaline earth metal element in the catalyst deviates from the range of 1 × 10 ^{-8 to} 5 × 10 ^-5 equivalent per mol of the aromatic diol compound, the obtained aromatic polycarbonate is There are problems that various physical properties are adversely affected, that the transesterification reaction does not proceed sufficiently and a high molecular weight aromatic polycarbonate cannot be obtained.

As the nitrogen-containing basic compound as a catalyst, for example, tetramethylammonium hydroxide (Me ₄ NOH), tetraethylammonium hydroxide (Et ₄ NOH), tetrabutylammonium hydroxide (Bu ₄ NOH), benzyl can be used. Trimethylammonium hydroxide (φ-CH ₂ (Me) ₃ NOH), hexadecyltrimethylammonium hydroxide, and other ammonium hydroxides having alkyl, aryl, or alkylaryl groups, triethylamine, tributylamine, dimethylbenzylamine, hexadecyl Tertiary amines such as dimethylamine, or tetramethylammonium borohydride (Me ₄ NB
H ₄ ), tetrabutylammonium borohydride (Bu ₄ NBH ₄ ), tetrabutylammonium tetraphenylborate (Me ₄ NBPh ₄ ), tetrabutylammonium tetraphenylborate (Bu ₄ NBPh ₄ ), and other basic salts can be given. it can.

The nitrogen-containing basic compound is a nitrogen-containing basic compound.
When the ammonium nitrogen atom in the compound is combined with an aromatic diol compound
1 x 10 per mole of product^-Five~ 5 x 10^-3At the rate of equivalent
It is preferably used. A more desirable ratio is based on the same criteria.
2 x 10^-Five~ 5 x 10^-FourIt is the ratio of equivalent weight. In particular
Preferred ratio is 5 × 10 based on the same criteria^-Five~ 5 x 10 ^-Four
It is the ratio of equivalent weight.

In the present specification, a charged aromatic diol compound (also referred to as an aromatic dihydroxy compound)
The ratio of the alkali metal compound, the alkaline earth metal compound, and the nitrogen-containing basic compound relative to
(Numerical value) equivalent Z (compound name) amount ”,
This is because, for example, Z is sodium phenoxide or 2,2
Z has one sodium atom such as bis (4-hydroxyphenyl) propane monosodium salt or one basic nitrogen such as triethylamine, Z
Means that the amount of W is equivalent to W mol.
If it is two such as -bis (4-hydroxyphenyl) propane disodium salt, it means that the amount is equivalent to W / 2 mol.

In the polycondensation reaction of the present invention, if necessary, at least one cocatalyst selected from the group consisting of an oxo acid of Group 14 element of the periodic table and an oxide of the same, together with the above catalyst. Can coexist.

By using these co-catalysts in a specific ratio, a branching reaction that easily occurs during the polycondensation reaction without impairing the end-capping reaction and the polycondensation reaction rate, and foreign substances in the apparatus during molding processing It is possible to more effectively suppress undesired side reactions such as the generation and burning of the.

Various proposals have hitherto been made for obtaining an aromatic polycarbonate having an excellent hue by the transesterification method using the above-mentioned raw materials and having a small foreign matter content. As an example of such a proposal, for example, the kind and amount of the catalyst to be used, the reaction atmosphere, the proposal from the chemical aspect such as the control of foreign matters and impurities in the raw material, the type and material of the reactor, There are proposals from the aspect of process such as the type and surface property of the pipe for transferring the reaction mixture, the flow velocity and temperature in the pipe, the heat transfer area of the apparatus and the stirring strength. However, it cannot be said that the stable production of excellent quality polycarbonate has been completely achieved, and further improvement is required.

In view of the present situation as described above, the present inventors repeatedly polymerized the aromatic polycarbonate using the transesterification method for several weeks, and then repeatedly opened and inspected the equipment used to check for deterioration of quality. As a result of investigating the cause, the inventors have found that by precisely controlling the temperature of the reaction unit by dividing it according to its function, the pollution of the polymerization equipment is reduced and the quality of the obtained polycarbonate is improved, and the present invention was reached.

In the present invention, the reaction unit includes a reaction tank body, a pipe portion for receiving a reaction mixture into the reaction tank body from an apparatus installed adjacent to the reaction tank body, and the reaction tank body. A pipe portion for connecting a condenser or a rectification tower to discharge by-product vapor generated in the reaction, and a pipe portion for supplying the polymerization mixture generated in the reaction tank body to an apparatus installed adjacent to the downstream side. Consists of. Further, the reaction unit also includes a vacuum generator or an inert gas supplier for discharging the reaction by-product vapor and keeping the pressure of the reaction tank main body constant, and further,
When a rectification column is installed to separate the reaction by-product from the raw material, the rectification column is also included in the reaction unit.

In the present invention, the reaction mixture means a mixture of the raw material monomers and a polymerization product mainly composed of a prepolymer obtained by transesterification of the raw material mixture. The installed device is a device for adjusting the raw material mixture, a device for storing the adjusted raw material mixture, a reaction tank for producing a prepolymer, a preheater for preheating the reaction target mixture, and a filter for the reaction target mixture. Means a filter, etc.

Further, the apparatus installed adjacent to the downstream of the reaction vessel main body means a reaction vessel for further polymerizing the polymerization product obtained in the reaction vessel, and a catalyst deactivator for the obtained polymerization product. And a mixer such as a ruder or kneader for adding various additives, a filter for filtering the obtained polymerization product, and a die for molding into a desired form.

As a result of repeating the disassembly and inspection of the polymerization equipment that has been operating for a long period of time, the inventors of the present invention have found that the portion of the by-product exhaust line attached to the reaction tank or the by-product vapor attached to the reaction tank is not the main body of the reaction tank or the contact with It was confirmed that the reactant supply line and the polymerization product transfer line obtained by the reaction were contaminated with the operating time. And this contamination can be remarkably suppressed by controlling the temperature suitable for each part, and the quality such as hue and foreign matter content of the resulting polymerization product can be maintained at an excellent level for a long time. Found. In the conventional method, these parts attached to the reaction tank are generally kept at the same temperature as the reaction tank main body, and the method of the present invention is completely different from this.

In the present invention, the pipe part for connecting the reaction tank body and the condenser or the rectification column to discharge the by-product vapor generated by the reaction is a high-temperature vapor mainly composed of a substance by-produced in the transesterification reaction. It means a part including a so-called gas phase part that is in contact with the reaction liquid and is not in contact with the reaction liquid in the reaction tank main body. If a rectification column is installed between the reaction tank body and the by-product vapor condenser in order to separate the raw material monomers contained in the by-product vapor, the vapor temperature will drop in the rectification column. It is not necessary to include the gas phase part of the above as a target, and it means the part from the reaction tank main body to the rectification tower inlet. In the present invention, the portion contacting with the high-temperature vapor mainly composed of the substance by-produced in the transesterification reaction is completely covered with the heating medium jacket, and the temperature of the heating medium flowing into the jacket is controlled by the reaction liquid in the corresponding reaction tank. 5 ° C to 35 ° C higher than the temperature (t1 ° C),
It is preferably maintained at 5 ° C to 20 ° C higher. If the temperature is lower than this temperature, the polymerization mixture that is scattered from the reaction vessel along with the by-product vapor adheres to the wall of the vapor phase of the reaction vessel and the wall of the steam discharge pipe, causing crystallization and heat deterioration, resulting in contamination of the reaction unit. . On the other hand, when the temperature is higher than this temperature, the scattered polymerization mixture is concentrated and deposited on the vessel wall and the tube wall, causing thermal deterioration and contaminating the reaction unit.

In the present invention, the pipe portion for receiving the reaction mixture from the apparatus installed adjacent to the upstream side of the reaction vessel body is completely covered with the heating medium jacket and the heating medium flowing into the jacket is covered. The temperature is t2 when the temperature of the reaction liquid in the reaction tank is t1 ° C. and the internal temperature of the upstream device is t2 ° C.
To a temperature between t1 and t1, preferably near t2. By doing so, it becomes possible to suppress the contamination of the piping portion.

Further, in the present invention, the pipe portion for supplying the polymerization mixture produced in the reaction vessel main body to the apparatus installed adjacently on the downstream side is completely covered with the heating medium jacket and the temperature of the heating medium flowing into the jacket. The temperature of the reaction solution in the reaction tank is t
When the internal temperature of the downstream device is 1 ° C and t3 ° C, from t1 to t
Maintain a temperature between 3 and preferably near t1. By doing so, it becomes possible to suppress the contamination of the piping portion.

It is not clear why the contamination of the reaction unit is prevented by maintaining the temperature of the pipe portion for receiving the reaction mixture and the temperature of the pipe portion for supplying the polymerization mixture at such a temperature, but it is not clear. The pressure of these pipes connected to the main body is close to the pressure of the main body of the reaction tank, and the conditions are such that the transesterification reaction can sufficiently occur, while the removal of the by-product is difficult to occur. Therefore, by bringing the temperature of the pipe part closer to the internal temperature of the equipment located upstream in the flow direction of the reaction mixture, suppressing the excessive transesterification reaction occurring in the pipe part suppresses the contamination of the pipe part and the reaction. It is considered that the whole unit is prevented from being contaminated.

In the present invention, the temperature of each jacket installed in the reaction unit must be strictly controlled. Therefore, the temperature difference between the temperature of the heat medium flowing into each jacket and the temperature of the heat medium flowing out of each jacket must be kept within 20 ° C, preferably within 10 ° C. In particular, in the jacket of each piping portion which is not intended to substantially cause the transesterification reaction as described above, the temperature difference between the inflowing heat medium and the outflowing heat medium is preferably within 5 ° C, more preferably 3 ° C. Manage within.

In the practice of the present invention, a plurality of temperature levels of heating medium are required. There is no particular limitation on the method for producing such a heat medium, but the following method is suitable for adjusting the heat medium at various levels of temperature and can be preferably used in the present invention.

In the present invention, the heat medium to be supplied to each jacket has a heat medium heater, a heat medium having a temperature higher than the set temperature of any jacket flows, a main heat medium circulation loop independent of each jacket, and each jacket. A heat medium having a desired temperature is prepared by using a heat medium temperature adjusting system composed of a sub heat medium circulation loop connecting the outlet and the inlet. More specifically, a)
By connecting the heat medium that flows into each jacket of the reaction unit and the heat medium that flows out by a pipe, an independent circulation system is established for each temperature level. B) A pump for circulation is installed in each circulation system and the heat medium flows out from the jacket. If the temperature of the heat medium is higher than the temperature of the heat medium flowing in, a cooler is installed to cool the heat medium flowing out and enter the circulation pump at a temperature lower than the temperature of the heat medium flowing into the jacket. c) A thermometer for measuring the temperature of the heat medium on the outlet side of the heat medium circulation pump, and a heat medium having a temperature higher than that of the main heat medium circulation system in order to maintain the measured temperature at the temperature of the heat medium flowing into the jacket. Set up a mechanism to inject
d) The temperature of the heat medium flowing into each jacket is installed on the inlet side of the heat medium pump by installing a mechanism for discharging an amount of heat medium commensurate with the injected high temperature heat medium into a circulation system in which the high temperature heat medium circulates. To control. According to this method, it is possible to prepare heat mediums having various temperature levels with one heat medium heater, which is very effective for economically implementing the present invention. As an application of this method, when there are multiple jackets with slightly different temperature levels, a sub heat medium circulation loop is formed by connecting these jackets in series, and the heat medium flowing out from the high temperature jacket is cooled appropriately. After controlling the temperature with, supply it to a low temperature jacket, form a sub heat medium circulation loop connecting these jackets in parallel, and after controlling the temperature of the heat medium set to the highest jacket temperature with a cooler as appropriate, It is also possible to reduce the number of sub heat medium circulation loops by supplying to a low temperature jacket.

The form of equipment for carrying out the present invention may be a continuous type or a batch type, but this is a preferable measure because a remarkable effect can be obtained in continuous equipment which requires long-term operation. When the present invention is carried out continuously, for example, devices having respective functions such as raw material adjustment, raw material supply, initial polymerization, and late polymerization are arranged in series, and the catalyst can be supplied to a polymerization tank in another series as needed. You can list the equipment.

In such continuous polymerization equipment, the dissolution adjustment of the raw materials may be carried out intermittently or continuously. When intermittently carried out, after a fixed amount of molten carbonic acid diester is charged into the raw material adjusting tank, the molar ratio of the carbonic acid diester to the aromatic dihydroxy compound is usually 0.8 to 1.5, preferably 0.95. 1.1 More preferably, the aromatic dihydroxy compound is gradually charged and uniformly melted while stirring so as to be 1.0 to 1.05, and then maintained at a constant temperature and transferred to a raw material supply tank. In this case, the temperature depends on the melting point of the raw material, but is usually 100-
180 ° C. is used.

When continuously adjusting the dissolution of the raw materials, the molten carbonic acid diester and the molten or powdered aromatic dihydroxy compound are continuously supplied at a constant ratio to an adjusting tank equipped with a stirrer. To be done. In this case, the raw material adjusting tank and the raw material supplying tank can also serve as the raw material adjusting tank and the raw material supplying tank when the molten carbonic acid diester and the molten aromatic dihydroxy compound are mixed in a pipe equipped with a line mixer. Both can be omitted. In these cases, it is necessary to maintain the temperature above the melting point of each raw material and mixture, and usually 100 to 180 ° C is used.

There are no particular restrictions on the material of the equipment used for dissolution adjustment of these raw materials, but materials with a high iron content should be avoided, and stainless steel is usually used.

In the operation of adjusting the dissolution of the raw materials, the presence of air, particularly oxygen should be avoided, and the apparatus used for the dissolution adjustment should be sufficiently replaced with an inert gas such as nitrogen, and the inert gas should be used during the operation. It is preferable to carry out purging with.

The raw material prepared in this manner is filtered for the purpose of removing minute foreign matters existing in the raw material, and then quantitatively supplied to the initial polymerization tank by using a metering pump or the like.

As the catalyst used for the transesterification reaction, a group of equipment having a system similar to the raw material adjustment is used. Supplied at a fixed rate.
Transesterification catalysts are often used in the form of being dissolved or dispersed in a solvent, and in this case, they affect the reaction of water, monohydroxy compounds such as phenols, aromatic dihydroxy compounds used as raw materials, or carbonic acid diesters. A substance that does not give is preferably used as a solvent.

The initial polymerization tank is a polymerization tank for carrying out the initial region of the transesterification reaction. The initial region of the transesterification reaction means that the viscosity of the polymer produced as a result of the reaction is low and there are relatively large amounts of unreacted aromatic dihydroxy compounds and carbonic acid diesters. It means the region where the diffusion resistance in liquid can be ignored when considering removal to the outside of the system. In addition, since a large amount of monohydroxy compound is by-produced in the initial region of transesterification, it is necessary to supply a large amount of heat in order to evaporate and remove it from the reaction system. It is also an area of control. The initial region of such a transesterification reaction is a region where the viscosity average molecular weight of the obtained polymer is less than 8000, and it is not necessary to consider the liquid depth of the reaction liquid as the type of equipment used, so hold-up is A vertical stirring tank capable of providing a large and large heat transfer area is preferably used. The initial polymerization tank does not need to be configured with one vertical stirring tank, but is configured with one or more vertical stirring tanks depending on the production capacity and the like. When a plurality of vertical stirring tanks are installed in series to perform the initial region of the transesterification reaction, the final vertical stirring tank is supplied with the reaction product having undergone polymerization to some extent. In order to effectively use the vertical stirring tank, it is preferable that the viscosity average molecular weight of the supplied polymer is less than 5,000.

A large vertical heat transfer area is required for the vertical stirring tank used for the initial polymerization, and the following two methods have been conventionally used to realize this, that is, a method for installing a heat transfer coil in the tank (internal A method is known in which a heat exchanger is attached to the outside of the coil) and the heat exchanger is connected to the outside by a circulation line (external heat exchange).

The vertical reactor used in the initial polymerization is additionally provided with a rectification column equipped with a reflux mechanism for separating the monohydroxy compound generated in the reaction from the carbonic acid diester as a raw material. In this case, a vertical stirring tank having the same operating pressure can share a rectification column equipped with one reflux mechanism.

When a plurality of reactors are used, it is important to control the residence time of each reactor to a constant level. The liquid level is controlled by using the head and a control valve is arranged in the transfer pipe to control the reactor level. Liquid level management linked to the meter, and liquid level management such as gear pumps and other quantitative liquid transfer pumps that are linked to the level meter of the reactor are implemented. Maintains the residence time in the individual reactors for 5 hours or less, preferably 2 hours or less, more preferably 1 hour or less.

Further, the liquid contact part of the reactor used for the initial polymerization is preferably made of a material containing less iron, and nickel, stainless steel or the like is preferably used.

The operating conditions of the reactor for the initial polymerization are 180 to 2
50 ° C., preferably 200-250 ° C. and 100-
A pressure of 10 Torr is used. Further, it is preferable that the operating temperature and the degree of vacuum are successively strengthened as the transesterification reaction proceeds. Thus, in the reactor of the initial polymerization, the viscosity average molecular weight is 1,000 to 8,000, preferably 4,000.
Polymerization up to ~ 8000 and the reaction rate of raw material is 95%
Or more, preferably 99% or more, more preferably 99.5.
Increase to more than%.

The reaction product produced in the initial polymerization is quantitatively supplied to the reactor for the latter polymerization by using a gear pump or the like. In this process, the reaction product may be filtered for the purpose of removing foreign matters as necessary. . As a filter used for this purpose, a known filter such as a candle type, a pleated type, a disc type or the like is preferably used, and an opening thereof is 20 μm or less, preferably 10 μm or less.

In the present invention, the reactor for the latter-stage polymerization does not mean one device, but means a group of devices for carrying out the latter-stage region of the transesterification reaction, and the latter-stage region of the transesterification reaction means the result of the reaction. The resulting polymer has high viscosity and relatively few terminal OH groups and phenyl groups involved in transesterification reaction. As a result, diffusion in liquid is considered in consideration of removal of by-product monohydroxy compound out of the reaction system. It means the area where resistance cannot be ignored. Actually, it is preferable that the reactor for the latter polymerization referred to in the present invention is composed of one or more horizontal stirring tanks depending on the production capacity of polycarbonate and the like. Since each horizontal stirring tank is operated at a high degree of vacuum, it does not have a rectification column and is directly connected to a vacuum generator via a collector for low molecular weight substances such as monohydroxy compounds generated. For the purpose of preventing heat radiation, removing the heat of stirring and maintaining the operating temperature, a jacket provided throughout is preferably used. The horizontal stirring tank may be a uniaxial reactor or a biaxial reactor. Generally, the viscosity of the reaction product is 8000 poise or less, preferably 6000 poise, under the operating conditions.
The horizontal monoaxial reactor is preferably used below 4,000 poise or less, and the horizontal biaxial reactor is preferably used at a viscosity of more than 4000 poise. In this case, stirring blades having various shapes are used to widen the surface area of the reaction solution and reduce the retention area. For example, eyeglass blades, lattice blades (Hitachi Ltd.), SCR, N-SCR , HVR (above, Mitsubishi Heavy Industries), BIVOLAK (Sumitomo Heavy Industries), RTC
(Buss SMS), ORP, CRP, DISCOT
HERMB (LIST) and the like are preferably used. Further, when the viscosity of the reaction product exceeds 5000 poise, a reactor having a uniaxial or biaxial screw for extracting the reaction product is preferably used.

When using a plurality of reactors, it is important to control the residence time of each reactor to be constant. For example, a quantitative liquid feed pump such as a gear pump is arranged in the transfer pipe to feed the liquid. Liquid level control and the like in which the amount is linked to the level meter of the reactor are carried out, and usually the residence time of each reactor is maintained at 10 hours or less, preferably 5 hours or less, more preferably 2 hours or less.

Further, the material used in the liquid contact part of the reaction tank for the latter polymerization is preferably a material having less iron, for example, nickel, stainless steel or the like is preferably used.

The operating conditions for the latter polymerization are 250 to 300 ° C.
Preferably, the temperature is 260 to 290 ° C. and 10 to 0.1 To.
A pressure of rr, preferably 5-0.5 Torr, is used. Further, it is preferable that the operating temperature and the degree of vacuum are successively strengthened in the subsequent stirring tank. Thus, in the latter stage reaction, the viscosity average molecular weight is 10,000 or more, preferably 15 or more, depending on the purpose.
Polymerization is performed up to 000 or more.

The reaction product produced in the latter-stage polymerization tank is quantitatively extracted using a gear pump or the like, and after adding additives as necessary, it is commercialized, but foreign substances are removed as necessary during this process. The reaction product may be filtered for the purpose. As the filter used for this purpose, a known filter such as a candle type, a pleated type, a disc type or the like is preferably used, and the opening thereof is 40 µ or less when the viscosity average molecular weight of the product is 20,000 or less, and 100 µ or less when it is more than that. Those of are preferably used.

The method of the present invention is preferably used for carrying out initial polymerization and late polymerization using such continuous equipment.

It is also possible to add a catalyst deactivator to the polycarbonate obtained in the present invention.

As the deactivator used in the present invention, known deactivators are effectively used. Among them, ammonium salts of sulfonic acid and phosphonium salts are preferable, and further dodecylbenzenesulfonic acid tetrabutylphosphonium salt and the like. The above salts of dodecylbenzenesulfonic acid and the above salts of paratoluenesulfonic acid such as tetrabutylammonium paratoluenesulfonic acid are preferable. As sulfonic acid esters, methyl benzene sulfonate, ethyl benzene sulfonate, butyl benzene sulfonate, octyl benzene sulfonate, phenyl benzene sulfonate,
Methyl paratoluenesulfonate, ethyl paratoluenesulfonate, butyl paratoluenesulfonate, octyl paratoluenesulfonate, phenyl paratoluenesulfonate, etc. are preferably used, and among them, dodecylbenzenesulfonic acid tetrabutylphosphonium salt is most preferably used. To be done.

The amount of these deactivators to be used is 0.5 to 50 mol, preferably 0.5 to 10 mol, per 1 mol of the polymerization catalyst selected from alkali metal compounds and / or alkaline earth metal compounds. It can be used in a molar ratio, more preferably 0.8 to 5 mol.

These quenching agents are added or kneaded directly or after being dissolved or dispersed in an appropriate solvent to the molten polycarbonate. There is no particular limitation on the equipment used to carry out such an operation, but for example, a biaxial ruder or the like is preferable, and when the deactivator is dissolved or dispersed in a solvent, a biaxial ruder with a vent is particularly preferably used. To be done.

Further, in the present invention, additives can be added to the polycarbonate within a range not impairing the object of the present invention. This additive is preferably added to the polycarbonate in a molten state in the same manner as the deactivator, and examples of such an additive include a heat resistance stabilizer, an epoxy compound, an ultraviolet absorber, a release agent, a colorant, and a slip agent. Examples thereof include agents, antiblocking agents, lubricants, organic fillers, inorganic fillers and the like.

Among these, heat stabilizers, ultraviolet absorbers, release agents, colorants and the like are particularly commonly used, and these can be used in combination of two or more kinds.

The heat resistance stabilizer used in the present invention includes
Examples thereof include phosphorus compounds, phenol-based stabilizers, organic thioether-based stabilizers, hindered amine-based stabilizers, and the like.

As the ultraviolet absorber, a general ultraviolet absorber is used, and examples thereof include salicylic acid type ultraviolet absorbers, benzophenone type ultraviolet absorbers, benzotriazole type ultraviolet absorbers, and cyanoacrylate type ultraviolet absorbers. I can name it.

As the release agent, a generally known release agent can be used. For example, hydrocarbon-based release agents such as paraffins, fatty acid-based release agents such as stearic acid, and stearic acid amides. Fatty acid amide release agents such as, stearyl alcohol, alcohol release agents such as pentaerythritol, fatty acid ester release agents such as glycerin monostearate and pentaerythritol stearate, silicone release agents such as silicone oil Etc. can be mentioned.

As the colorant, organic or inorganic pigments and dyes can be used.

There are no particular restrictions on the method of adding these additives. For example, they may be added directly to the polycarbonate, or master pellets or master powder may be prepared and added.

[0076]

According to the present invention, the reaction tank main body, the pipe portion for receiving the reaction mixture from the apparatus installed upstream and adjacent to the reaction tank main body, the reaction tank main body and the condenser are connected. A piping part for discharging the by-product vapor generated in the reaction,
An aromatic dihydroxy compound and a carbonic acid diester are esterified in the presence of a catalyst by using a plurality of reaction units each including a piping section for supplying the polymerization mixture produced in the reaction vessel main body to an apparatus installed adjacent to the downstream side. In the method for producing aromatic polycarbonate by exchanging them, by covering each part constituting the reaction unit with a heating medium jacket and maintaining the temperature of each part at an independent specific temperature for a long period of time, stable A method for producing a polycarbonate capable of producing a polymerization reaction product having an improved hue can be provided.

[0077]

EXAMPLES Examples and comparative examples will be described below. It should be noted that this example is for the purpose of illustrating the present invention, and the present invention is not limited to this example.

To measure the viscosity average molecular weight in Examples and Comparative Examples, a 0.7 g / dl methylene chloride solution was used to measure the intrinsic viscosity using an Ubbelohde viscometer, and the viscosity average molecular weight was determined by the following formula.

[Η] = 1.23 × 10 ⁻⁴ × M ^{0.83 As} a measured value of polymer hue, polycarbonate pellets (minor axis × major axis × length (mm) = 2.5 × 3.3 ×)
3.0) L, a, b values are ND-100 manufactured by Nippon Denshoku Industries Co., Ltd.
Among the results measured by the reflection method using 1DP, the b value was used as a measure of yellowness.

The amount of foreign matter in the polymer was determined by dissolving 1 kg of polycarbonate pellets in 5 L of methylene chloride and then filtering using a filter having an opening of 30 μ, and counting the number of foreign matter collected on the filter.

Terminal hydroxyl group concentration (%) = (number of terminal hydroxyl groups /
Total number of terminals) × 100 [Example 1] Diphenyl carbonate was added to 1.0 mol to 1 mol of 2,2-bis (4-hydroxyphenyl) propane.
The mixture was charged into a melting tank equipped with a stirrer at a ratio of 2 mol, and after nitrogen substitution, the mixture was heated and dissolved at 150 ° C.
It was transferred to a raw material storage tank whose temperature was controlled.

The initial polymerization after the raw material storage tank is composed of two vertical stirring tanks installed in series, and after continuously producing the prepolymer, the obtained prepolymer was fed from one horizontal stirring tank. Then, it was continuously polymerized in the latter polymerization to obtain a polycarbonate.

The details of the continuous operation will be described below.

100 from the raw material storage tank using a metering pump
It is fed through a 1 μm raw material filter in an amount of kg / hr to a vertical reaction tank of the first stage for continuously performing initial polymerization, and is dissolved in phenol containing 10 wt% of water as an ester exchange catalyst in the middle of the feed line. Bisphenol A disodium salt filtered with a 1 μm filter and tetramethylammonium hydroxide were added to 1 mol of 2,2-bis (4-hydroxyphenyl) propane.
To give 0.5 × 10 ⁻⁶ equivalent and 1 × 10 ⁻⁴ equivalent, respectively (28 ppm of bisphenol A disodium salt and 0.
0.54 wt% PhOH / water solution containing 37 wt% tetramethylammonium hydroxide to the raw material mixture
%) Were continuously injected and mixed, and the mixture of the raw material and the catalyst was preheated to 190 ° C. by a preheater, and then continuously supplied to the first vertical reaction tank through a pipe completely covered with a jacket. . The temperatures of the heat medium flowing into the jacket of the raw material mixture supply pipe and the temperature of the heat medium flowing out were 190 ° C and 188 ° C, respectively.

The first-stage reaction tank is a vertical stirring tank equipped internally with a heating coil having a jacket divided into a liquid phase portion and a gas phase portion, and 250 is provided in the jacket of the liquid phase portion and the heating coil. Supplying a heating medium of ℃, the internal temperature is 220 ℃, the internal pressure is 1
It was maintained at 3333 Pa (100 mmHg). The temperature of the heat medium flowing out from the liquid phase jacket was 246 ° C. Further, a heating medium of 230 ° C. is supplied to the jacket of the gas phase portion, and the temperature of the heating medium flowing out of the jacket is 227 ° C.
Met.

Phenol produced and vaporized in the first vertical reaction tank and raw materials partially vaporized (2,2-bis (4-hydroxyphenyl) propane and diphenylcarbonate)
Is introduced into a rectification tower attached to the reaction tank through a pipe having a jacket connected to the gas phase jacket of the reaction tank main body, and after continuous rectification, only phenol is distilled out of the reaction system for transesterification. The reaction was carried out continuously.

The prepolymer produced in the first vertical reaction tank was continuously withdrawn from the bottom of the tank using a gear pump through a pipe completely covered with a jacket and before the second vertical reaction tank. The preheater installed was continuously fed.
A heating medium of 222 ° C. was supplied to the jacket of the extraction pipe, and the heating medium temperature flowing out of the jacket was 220 ° C. The prepolymer was withdrawn from a valve installed on the outlet side of the gear pump and the viscosity average molecular weight was measured to be 1500.

The prepolymer was heated to 260 ° C. by a preheater and then continuously fed into a second vertical reaction tank through a pipe completely covered with a jacket. The temperature of the heat medium on the inlet side of the pipe jacket is 260 ° C, and the temperature of the heat medium on the outlet side is 2 ° C.
It was 58 ° C. The second-stage reaction tank is a vertical stirring tank having a heating coil inside which has a jacket divided into a liquid phase part and a gas phase part in the same manner as the first-stage reaction tank. A heating medium of 275 ° C is supplied to the jacket and the heating coil so that the internal temperature is 260 ° C and the internal pressure is 2000 Pa (15 mmH).
g). The temperature of the heat medium flowing out from the liquid phase jacket was 270 ° C. A heating medium of 270 ° C. was supplied to the jacket of the gas phase portion, and the temperature of the heating medium flowing out of the jacket was 268 ° C.

Phenol produced and vaporized in the second vertical reaction tank and partially vaporized raw materials (2,2-bis (4-hydroxyphenyl) propane and diphenylcarbonate)
G) is led to a rectification column attached to the reaction tank through a pipe having a jacket connected to the gas phase jacket of the reaction tank main body, and after continuous rectification, only phenol is distilled out of the reaction system and further esterified. The exchange reaction was carried out continuously.

The prepolymer obtained in the second-stage reaction tank was continuously withdrawn from the bottom of the tank using a gear pump through a pipe completely covered with a jacket, and continuously fed to the final polycondensation reactor. . The heat medium at 263 ° C. was supplied to the jacket of the extraction pipe, and the temperature of the heat medium flowing out from the jacket was 260 ° C. The prepolymer was withdrawn from a valve installed on the outlet side of the gear pump and the viscosity average molecular weight was measured to be 6000.

The final-stage polymerization reactor is a self-cleaning horizontal uniaxial reactor, which has a function of applying and renewing the reaction solution all over the inner wall of the reactor, and the reactor wall that is in direct contact with the by-product vapor is used. Since it does not have it, it is covered with a single jacket, and the heating temperature of 268 ° C is supplied to the jacket, and the internal temperature is adjusted to 270 by flowing out at 271 ° C.
The internal pressure was maintained at 133 ° C (1 mmHg) at 0 ° C.

Phenol and the like produced and vaporized in the final horizontal single-screw reactor are heated to a temperature of 277 ° C. when a heating medium of 280 ° C. flows in.
It was led to a condenser through a pipe completely covered with a jacket flowing out of, and the polycondensation reaction was allowed to proceed continuously while removing all out of the reaction system.

The polymer obtained in the final polycondensation reactor was continuously withdrawn using a gear pump at 275 ° C. through a pipe completely covered with a jacket into which a heating medium at 273 ° C. flows in and flows out at 271 ° C. After being extruded from the die maintained at, pelletized by a pelletizer. The viscosity average molecular weight was 15100 as a result of evaluating the characteristics of the pellets obtained by continuing the operation for 1 month by such a method.
To 15300, and the foreign matter content is 5 to 10 pieces / Kg
The hue was maintained at a good level with ab value of -0.3 to -0.5.

Further, the heat medium supplied to each jacket forms an independent sub-circulation loop, and 310
Each temperature was maintained by accepting the heat medium from the main circulation loop set to ℃. Further, since only the heat medium flowing out from the main body jacket of the final horizontal reactor has a high temperature, it was possible to control the temperature by injecting the heat medium at 310 ° C. by cooling through the cooler.

[Example 2] The prepolymer produced in the first vertical reaction tank was heated to 260 ° C by a preheater installed in front of the second vertical reaction tank, and then 2 from the preheater. The operation was continued for one month in the same manner as in Example 1 except that the heating medium at 275 ° C. was flowed into the jacket of the pipe to the vertical reaction tank at the second stage and was discharged at 272 ° C.

As a result of evaluating the characteristics of the obtained pellets,
The viscosity average molecular weight is 15100 to 15300,
The foreign matter content is 5 to 10 pieces / kg, and the hue has a b value of −
It was 0.3 to -0.4 and maintained a good level.

Comparative Example 1 Phenol produced and vaporized in the jacket of the vapor phase portion of the first-stage reaction tank and in the vertical reaction vessel of the first stage, and a partially vaporized raw material (2,2-bis (4 -Hydroxyphenyl) propane and diphenylcarbonate-
To a rectification tower attached to the reaction tank, a heating medium of 220 ° C. is supplied to the jacket, and the temperature of the heating medium flowing out of the jacket is set to 217 ° C. to generate in the first vertical reaction tank. The prepolymer was continuously fed to the preheater installed in front of the second vertical reaction tank.
A heating medium of 3 ° C. was supplied, the temperature of the heating medium flowing out of the jacket was set to 269 ° C., and the prepolymer heated by the preheater was heated to 2 ° C.
A heating medium of 273 ° C was supplied to the jacket of the pipe that continuously feeds the vertical reaction tank of the second stage, and the temperature of the heating medium flowing out of the jacket was set to 270 ° C, and the jacket of the gas phase part of the second reaction vessel was set. And a phenol which is generated and vaporized in the vertical reaction tank of the second stage and a partially vaporized raw material (2,2-bis (4-
A heating medium of 260 ° C. is supplied to a jacket of a pipe for introducing (hydroxyphenyl) propane and diphenylcarbonate) to a rectifying column attached to a reaction tank, and the temperature of the heating medium flowing out from the jacket is set to 258 ° C. A heating medium of 273 ° C. is supplied to the jacket of the pipe for continuously feeding the prepolymer obtained in the reaction vessel of the second stage to the polycondensation reactor of the final stage, and the temperature of the heating medium flowing out of the jacket is set to 270 ° C. In the same manner as in Example 1 except that a heating medium of 273 ° C. is introduced into the jacket of a pipe for guiding phenol or the like produced and vaporized in the horizontal single-axis reactor to the condenser and is discharged at 270 ° C., in one month. Continued driving across.

As a result of evaluating the characteristics of the obtained pellets,
Although the viscosity average molecular weight was stable from 15100 to 15300, the foreign matter content gradually deteriorated from the good level of 10 particles / Kg as the operation continued, and increased to 92 particles / Kg by the end of operation. . The hue also showed a similar change in the b value, which was -0.3 to -0.4 at the beginning of the operation, but deteriorated to 0.7 just before the end of the operation.

[Comparative Example 2] Phenol produced and vaporized in the jacket of the vapor phase portion of the first-stage reaction tank and in the first vertical reaction vessel and a partially vaporized raw material (2,2-bis (4 -Hydroxyphenyl) propane and diphenylcarbonate-
To a rectification tower attached to the reaction tank, a heating medium of 220 ° C. is supplied to the jacket, and the temperature of the heating medium flowing out of the jacket is set to 217 ° C. And vaporized raw materials (2,2-bis (4-
A heating medium at 260 ° C. is supplied to a jacket of a pipe for introducing (hydroxyphenyl) propane and diphenylcarbonate) to a rectifying column attached to the reaction tank, and the temperature of the heating medium flowing out from the jacket is set to 258 ° C. In the same manner as in Example 1 except that a heating medium of 273 ° C. is introduced into the jacket of a pipe for guiding phenol or the like produced and vaporized in the horizontal single-axis reactor to the condenser and is discharged at 270 ° C., in one month. Continued driving across.

As a result of evaluating the characteristics of the obtained pellets,
Although the viscosity average molecular weight was stable from 15100 to 15300, the foreign matter content gradually deteriorated from the good level of 10 particles / Kg as the operation continued, and increased to 73 particles / Kg by the end of operation. . The hue also showed a similar change in the b value, which was -0.3 to -0.4 at the beginning of the operation but deteriorated to 0.5 at the end of the operation.

[Comparative Example 3] Phenol produced and vaporized in the jacket of the vapor phase portion of the first-stage reaction tank and in the first vertical reaction vessel and a partially vaporized raw material (2,2-bis (4 -Hydroxyphenyl) propane and diphenylcarbonate-
(2) is supplied to the jacket of the pipe leading to the rectification column attached to the reaction tank, and the temperature of the heat medium flowing out from the jacket is set to 240 ° C., and the vapor phase part of the second-stage reaction tank is set. And vaporized raw materials (2,2-bis (4-
(Hydroxyphenyl) propane and diphenylcarbonate) are supplied to the jacket of the pipe leading to the rectification column attached to the reaction tank, the heating medium at 300 ° C. is supplied, and the temperature of the heating medium flowing out from the jacket is 278 ° C. In the same manner as in Example 1 except that a heating medium at 310 ° C. is introduced into the jacket of a pipe for guiding phenol or the like generated and vaporized in the horizontal single-axis reactor to the condenser and is discharged at 270 ° C. within one month. Continued driving across.

As a result of evaluating the characteristics of the obtained pellets,
Although the viscosity average molecular weight was stable from 15100 to 15300, the foreign matter content gradually deteriorated from the good level of 10 particles / Kg with the continuation of the operation, and increased to 136 particles / Kg by the end of the operation. . The hue also showed a similar change in the b value, which was -0.2 to -0.3 at the beginning of the operation but deteriorated to 1.3 just before the end of the operation.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masashi Shimonari             2-1, Hinodecho, Iwakuni, Yamaguchi Prefecture Teijin Limited             Company Iwakuni Research Center (72) Inventor Katsushi Sasaki             2-1, Hinodecho, Iwakuni, Yamaguchi Prefecture Teijin Limited             Company Iwakuni Research Center F term (reference) 4J029 BB04A BB05A BB10A BB12A                       BB12B BB13A BB13B BF14A                       BG05X BG06X BG08X BG24X                       BH02 DB07 DB10 DB13 HC03                       HC04A HC05A KC01 KD02                       KD09 KE02 KE05 KE07 KJ01                       KJ05 LA01 LA05 LA14 LB07

Claims (3)

[Claims] 1. A reaction vessel main body, a pipe portion for receiving a reaction mixture from an apparatus installed upstream and adjacent to the reaction tank main body, and a by-product generated by a reaction connecting the reaction tank main body and a condenser. At least two reaction units each having a pipe part for discharging vapor and a pipe part for supplying the polymerization mixture generated in the reaction tank body to an apparatus installed adjacent to the downstream side.
In a method for producing an aromatic polycarbonate by transesterifying an aromatic dihydroxy compound and a carbonic acid diester in the presence of a catalyst using equipment installed in series, the reaction tank main body and a reaction mixture receiving pipe section The by-product discharge piping and the polymerization mixture withdrawing piping are each covered with a heating medium jacket, and the temperature of at least one reaction unit is the internal temperature of the reaction tank main body at t1 ° C, and the internal temperature of the apparatus installed upstream is t2 ° C. , The internal temperature of the equipment installed downstream is t
When the temperature is set to 3 ° C., the temperature of the heat medium flowing into the jacket of the by-product discharge piping is set to a temperature between t1 + 5 ° C. and t1 + 35 ° C., and the temperature of the heat medium flowing into the jacket of the reactant receiving piping is t2 to t1. And the temperature of the heat medium flowing into the jacket of the piping portion for withdrawing the polymerization mixture is t1.
A process for producing an aromatic polycarbonate, characterized in that the temperature is between 3 and t3. 2. The fragrance according to claim 1, wherein the temperature difference between the temperature of the heat medium flowing into each jacket of the reaction unit and the temperature of the heat medium flowing out from each jacket is within 20 ° C. Method for producing aromatic polycarbonate. 3. A) a circulation system independent for each temperature level by connecting a heat medium flowing into each jacket of the reaction unit and a heat medium flowing out to each other with a pipe, and b) a pump for circulation in each circulation system. In addition to installation, if the temperature of the heat medium flowing out of the jacket is higher than the temperature of the heat medium flowing in, to cool the heat medium flowing out and enter the circulation pump at a temperature lower than the temperature of the heat medium flowing into the jacket. Installed the cooler of
c) A thermometer for measuring the temperature of the heat medium and a mechanism for injecting a high-temperature heat medium for maintaining the measured temperature at the temperature of the heat medium flowing into the jacket are installed on the outlet side of the heat medium circulation pump. ,
d) A feature of controlling the temperature of the heat medium flowing into each jacket by installing a mechanism on the inlet side of the heat medium pump to discharge an amount of heat medium corresponding to the injected high temperature heat medium to the outside of the circulation system The method for producing an aromatic polycarbonate according to claim 1 or 2.