JPH0920822A - Production of aromatic polycarbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an aromatic polycarbonate good in reproducibility of molecular weight by measuring the deviation of the flow rate from the set value and controlling the feeds of an aqueous solution containing an alkali(ne earth) metallic base of an aromatic dihydroxy compound and a halogenated carbonyl compound, determining the residual ratio, leading the residual ratio into a correction ratio and correcting the feed rate. SOLUTION: The deviation of the flow rate from the set value is measured to control the feeds of an aqueous solution containing an alkali(ne earth) metallic base of an aromatic dihydroxy compound and a halogenated carbonyl compound. The concentration of the alkali(ne earth) metallic base of the aromatic dihydroxy compound in the aqueous phase taken out of the first vessel is measured to determine the residual ratio (b) based on the concentration of the feed solution. A correction ratio (a) is derived therefrom according to the deviation from the reference value of the residual ratio (b) and multiplied by the set flow rate for the aqueous solution containing the alkali(ne earth) metallic base of the aromatic dihydroxy compound to occasionally correct the feed rate to afford a polycarbonate in which the correction ratio (a) is determined from the residual ratio (b) by formulas I to III [(x) is the amount of a catalyst (mol% based on the aromatic dihydroxy compound); (y) is the residence time (min) in the first vessel and satisfies formula IV [(y) is >=1; (x) is >=0.0005; (xy) is >=0.5].

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an aromatic polycarbonate, and more particularly, to an aromatic polycarbonate having a good molecular weight reproducibility and a uniform mechanical, thermal and melt flowability on an industrial scale. The present invention relates to a method for continuously and efficiently manufacturing.

[0002]

2. Description of the Related Art Aromatic polycarbonates are excellent in high strength, high rigidity, heat resistance and impact resistance, and are also excellent in transparency, weather resistance, dimensional stability, electrical properties, etc. as engineering plastics in many fields. It is used.
In this way, aromatic polycarbonate has a wide variety of uses, and its molding has various forms such as precision parts with complicated shapes, thin-walled products, and large-sized thick products. Often needed.

Aromatic polycarbonate is a resin having a relatively high melt viscosity, and the shear rate dependence of the melt viscosity is extremely small, so that the change in fluidity due to injection pressure is small. That is, in forming an aromatic polycarbonate, it is a prerequisite that the control of temperature conditions is important and that the molecular weight of the resin is uniform. However, in mass production for general-purpose use, there are not a few troubles in which good reproducible molding is hindered due to variations from the target molecular weight of the resin.

Aromatic polycarbonates used in general applications are based on the method of JIS K-7210,
The melt viscosity measured under the conditions of a temperature of 280 ° C. and a load of 2.16 kg is in the range of about 3 to 20 g / min. From this range, the molecular weight of the product, that is, the melt viscosity is determined in consideration of the optimum melt fluidity determined by the shape of the molded product, the strength required for the intended use of the molded product, and the like. Currently, the applications that require precision molding are expanding,
It is important to improve the reproducibility of the melt viscosity of this product, and it is preferable that a product having a viscosity difference of about ± 0.5 g / min with respect to the target melt viscosity can be continuously manufactured.

In order to produce an aromatic polycarbonate of uniform quality, the molar ratio of the reaction between the aromatic dihydroxy compound and the carbonyl halide compound and the molar ratio between the aromatic dihydroxy compound and the molecular weight regulator are stabilized at a predetermined ratio. However, in continuous operation on an industrial scale, the amplitude of the feed amount of these raw materials sometimes leads to deviation from the desired molar ratio, which may cause variations in product quality. is there.

In order to solve this problem, a method has been devised to provide a product of uniform quality by inspecting various states of the reaction system during operation and automatically controlling the amount of raw material supplied to an appropriate value. There is. Japanese Unexamined Patent Publication No. 64-65126 is provided with an apparatus for automatically measuring a chloroformate terminal of a prepolycondensation oligomer and / or an apparatus for automatically measuring unreacted bisphenols in a polycondensation reaction solution in a polymerization reaction system, A method is shown in which the measured value output from the device is input to a control exercise system to automatically control the opening and closing of the raw material supply system valve. In this way, the reproducibility of product quality is improved by measuring the generation state of intermediates during polycondensation reaction and / or the amount of unreacted monomer at the end of polycondensation, and feeding it back to the raw material supply system to adjust the supply amount. It is said that it can be done. However, the chloroformate terminal of the oligomer in the pre-polycondensation system has various other factors such as reaction temperature, stirring condition, variation of catalyst amount and caustic amount, in addition to the molar ratio of reaction of aromatic dihydroxy compound and carbonyl halide compound. It is vulnerable to disturbance due to factors, and the fluctuation range of the terminal amount of chloroformate is large when subjected to disturbance.Therefore, if this measured value is used as a control factor, it will be difficult to control for stable operation. there were. Furthermore, there is also a method to monitor the unreacted monomer in the water phase of the polycondensation reaction liquid and control the change by feeding back the change to the raw material supply system. When is used as a control factor, a delay of the time required from the production of the oligomer to the completion of polycondensation occurs with respect to the raw material supply system, and there is a problem that the control does not match the current state of the prepolycondensation system. there were.

Japanese Unexamined Patent Publication No. 4-198213 discloses, as an operation control method for improving the reproducibility of the molecular weight of a product in a continuous production method of polycarbonate, phosgene, an alkaline aqueous solution of bisphenols, a molecular weight modifier and an organic solvent are continuously added. Viscosity, concentration and concentration in the organic phase containing the polycarbonate obtained by removing contaminant impurities in the organic phase containing the polycarbonate separated from the reaction mixture or the washing system A method is disclosed in which the viscosity average molecular weight of the polycarbonate is calculated by measuring the temperature, and the amount of the molecular weight regulator supplied to the polymerization reactor is controlled according to the value. With such a method, it is possible to control the operation of the product with a reproducible molecular weight to some extent, but the time required to obtain an organic phase in which polymerization has been completed does not lead to a delay in the control of the supply amount of the molecular weight regulator. Inevitable, if something goes wrong,
Since it takes time for the result of the correction to be reflected in the product, it is expected that a large loss will be incurred and the problem needs to be solved.

As described above, in the conventional technique, in industrial scale production of polycarbonate, it is necessary to quickly respond to changes in the reaction situation due to various disturbances and perform control for maintaining reproducibility of the molecular weight of the product. It was difficult to carry out stable continuous operation.

[0009]

The present invention relates to a method for producing an aromatic polycarbonate, and more specifically, it continuously produces an aromatic polycarbonate having good reproducibility of molecular weight, mechanical, thermal properties and melt flowability. In order to efficiently manufacture the product efficiently, it quickly responds to changes in the reaction situation due to various disturbances, and accurately performs control to maintain reproducibility of quality such as molecular weight of the product, achieving stable continuous operation. The purpose is to let.

[0010]

As a result of intensive studies to solve the above problems, the present inventors have found that the most important condition for producing an aromatic polycarbonate having a target molecular weight and quality with good reproducibility. When any disturbance acts on the molar ratio of the initial contact of the alkali metal or alkaline earth metal base of the aromatic dihydroxy compound and the carbonyl halide compound, an index for rapidly and clearly reflecting the state is Attention was paid to the concentration of the alkali metal or alkaline earth metal base of the unreacted aromatic dihydroxy compound existing in the aqueous phase after contact. And in the continuous production method of aromatic polycarbonate,
In particular, when the initial contact is carried out in a tank reactor and the operation is carried out under conditions where the residence time and the amount of catalyst at that time are in a preferable range, unreacted aromatics present in the aqueous phase after the initial contact It was found that the concentration of the alkali metal or alkaline earth metal base of the dihydroxy compound changes in a specific relationship with the state of the molar ratio of the initial contact. In this way, the concentration of the alkali metal or alkaline earth metal base of the unreacted aromatic dihydroxy compound existing in the aqueous phase after the initial contact is measured, and the raw material supply amount is adjusted using this as an index to perform the operation. Then, it was found that, before finally being taken out as a product and evaluated, an aromatic polycarbonate having a target molecular weight and quality can be stably produced. In addition, in the method of the present invention, not only the state of the molar ratio of the initial contact can be stably known by an accurate index, but also the raw material supply ratio can be grasped immediately after the completion of the initial contact. In a short time of several minutes to several tens of minutes, the necessary adjustment direction and adjustment amount of the raw material supply amount become clear, and there is an advantage that the response time to the correction operation is extremely fast. That is, it is possible to quickly respond to changes in the reaction situation due to disturbance, perform control for maintaining the reproducibility of the molecular weight of the product, and carry out stable continuous operation with it.
Maintaining the reproducibility of the product's molecular weight and quality by continuing stable and continuous operation, which was the purpose, was achieved by applying the above-mentioned technique to industrial operation, and completed the present invention.

That is, in the present invention, a plurality of tanks in which an aqueous solution of an alkali metal or alkaline earth metal base of at least one aromatic dihydroxy compound and a carbonyl halide compound are combined with a polymerization catalyst, a molecular weight modifier, and an organic solvent in a plurality of tanks are connected. In a method for producing an aromatic polycarbonate by continuously feeding and reacting in a type reactor, an alkali metal or alkaline earth metal base aqueous solution of an aromatic dihydroxy compound and a supply of a carbonyl halide compound are deviated in flow rate from a set value. While measuring and controlling, the alkali metal or alkaline earth metal base concentration of the aromatic dihydroxy compound in the aqueous phase extracted from the first tank is measured, and the residual ratio is calculated with respect to the concentration of the supply liquid. A correction ratio is derived according to the deviation from the standard value of the residual rate, and this is used as the aromatic dihydroxy compound. A method for producing an aromatic polycarbonate, characterized by multiplying a set flow rate of an alkali metal or alkaline earth metal base aqueous solution and correcting the supply amount at any time, wherein an alkali metal or alkaline earth metal base aqueous solution of an aromatic dihydroxy compound is prepared. The correction ratio (a) depending on the control flow rate is the concentration of the alkali metal or alkaline earth metal base of the aromatic dihydroxy compound in the aqueous phase extracted from the first tank of a plurality of connected tank reactors during the reaction. The method for producing an aromatic polycarbonate according to claim 1, wherein the residual rate (b:%) calculated by the following equation is used to obtain the following equation.

## EQU2 ## a = -0.018 * (b-11.5) +0.99 ... [13 <b] a = -0.022 * (b-11.5) +1.00 ... [10≤b≤ 13] a = −0.003 × (b-11.5) +1.03 ... [b <10] However, the catalyst amount (x: mol% relative to the aromatic dihydroxy compound) and the residence time in the first tank (y: Min) applies under the following conditions. logy <−2.19x + 1.84 [x ≧ 0.0005, y ≧ 1, xy ≧ 0.5]

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
In the present invention, an aqueous solution containing an aromatic dihydroxy compound, a carbonyl halide and an organic solvent are used. The aqueous solution containing an aromatic dihydroxy compound used in the present invention comprises at least one aromatic dihydroxy compound, an alkali metal or alkaline earth metal base, water, a molecular weight modifier, a polymerization catalyst, and optionally a branching agent.

The aromatic dihydroxy compound used in the present invention is a compound represented by the following formula (1) or (2). HO-Ar1-X-Ar2-OH (1) HO-Ar3-OH (2) In the above formula, Ar1, Ar2 and Ar3 each have a monocyclic divalent aromatic group, that is, a phenylene group or a substituent. Is a substituted phenylene group, the substituent,
Examples thereof include a halogen atom, a nitro group, an alkyl group, a cycloalkyl group, an alkenyl group, a hydrocarbon group such as an aralkyl group or an aryl group, and an alkoxy group.

Ar1 and Ar2 are both p-phenylene group, m-phenylene group or o-phenylene group, or one is p-phenylene group and the other is m-phenylene group or o-phenylene group. Are preferred, and it is particularly preferred that both Ar1 and Ar2 are p-phenylene groups. X is a linking group that connects Ar1 and Ar2, and is a single bond or a divalent hydrocarbon group, and further -O.
-, - S -, - SO -, - SO 2 -, - it may be a group containing atoms other than carbon and hydrogen CO- like. The divalent hydrocarbon group means a saturated hydrocarbon group such as methylene,
Examples thereof include alkylidene groups such as ethylene, 2,2-propylidene, cyclohexylidene, and cyclohexylidene having a substituent, but groups substituted with an aryl group are also included, and aromatic groups and other unsaturated groups are also included. It may be a hydrocarbon group containing the hydrocarbon group of.

Specific examples of the aromatic dihydroxy compound include bis (4-hydroxyphenyl) methane and 1,1-
Bis (4-hydroxyphenyl) ethane, 1,2-bis (4-hydroxyphenyl) ethane, bis (4-hydroxyphenyl) phenylmethane, bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) -1 -Naphthylmethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 2,2-bis (4-hydroxyphenyl) propane ["bisphenol A"], 2- (4-hydroxyphenyl) -2 −
(3-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, 1,1-bis (4
-Hydroxyphenyl) isobutane, 2,2-bis (4
-Hydroxyphenyl) octane, 2,2-bis (3-
Methyl-4-hydroxyphenyl) propane, 2,2-
Bis (3-ethyl-4-hydroxyphenyl) propane, 2,2-bis (3-n-propyl-4-hydroxyphenyl) propane, 2,2-bis (3-isopropyl-4-hydroxyphenyl) propane, 2 , 2-bis (3-sec-butyl-4-hydroxyphenyl) propane, 2,2-bis (3-tert-butyl-4-hydroxyphenyl) propane, 2,2-bis (3-cyclohexyl-4-hydroxy) Phenyl) propane, 2,2
-Bis (3-allyl-4-hydroxyphenyl) propane, 2,2-bis (3-methoxy-4-hydroxyphenyl) propane, 2,2-bis (3,5-dimethyl-4)
-Hydroxyphenyl) propane, 2,2-bis (2,3,5,6-tetramethyl-4-hydroxyphenyl) propane, 2,2-bis (3-chloro-4-hydroxyphenyl) propane, 2,2 -Bis (3,5-dichloro-4-hydroxyphenyl) propane, 2,2-
Bis (3-bromo-4-hydroxyphenyl) propane, 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane, 2,2-bis (2,6-dibromo-3,5-dimethyl- 4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) cyanomethane, 1
-Bis (hydroxyaryl) alkanes such as cyano-3,3-bis (4-hydroxyphenyl) butane and 2,2-bis (4-hydroxyphenyl) hexafluoropropane;

1,1-bis (4-hydroxyphenyl)
Cyclopentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane,
Bis (hydroxyaryl) cycloalkanes such as 1,1-bis (4-hydroxyphenyl) cycloheptane and 2,2-bis (4-hydroxyphenyl) adamantane; 4,4′-dihydroxydiphenyl ether, 4,
Dihydroxy diaryl ethers such as 4′-dihydroxy-3,3′-dimethyldiphenyl ether and ethylene glycol bis (4-hydroxyphenyl) ether; 4,4′-dihydroxydiphenyl sulfide,
A dihydroxydiaryl sulfide such as 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfide,
4,4'-dihydroxydiphenyl sulfoxide, 4,
Dihydroxy diaryl sulfoxides such as 4′-dihydroxy-3,3′-dimethyldiphenyl sulfoxide; 4,4′-dihydroxydiphenyl sulfone, 4,
Dihydroxydiarylsulfones such as 4′-dihydroxy-3,3′-dimethyldiphenylsulfone; bis (hydroxyaryl) ketones such as bis (4-hydroxyphenyl) ketone and bis (4-hydroxy-3-methylphenyl) ketone ;

Further, 6,6'-dihydroxy-3,
3,3 ′, 3′-Tetramethylspiro (bis) indane [“spirobiindanebisphenol”], trans-2,3-bis (4-hydroxyphenyl) -2-butene, 9,9-bis (4- Hydroxyphenyl) fluorene, 3,3-bis (4-hydroxyphenyl) -2-butanone, 1,6-bis (4-hydroxyphenyl)-
1,6-hexanedione, 1,1-dichloro-2,2-
Bis (4-hydroxyphenyl) ethylene, 1,1-dibromo-2,2-bis (4-hydroxyphenyl) ethylene, 1,1-dichloro-2,2-bis (5-phenoxy-4-hydroxyphenyl) ethylene , Α, α, α
′, Α′-Tetramethyl-α, α′-bis (4-hydroxyphenyl) -p-xylene, α, α, α ′, α′-
Examples thereof include tetramethyl-α, α′-bis (4-hydroxyphenyl) -m-xylene and 4,4′-dihydroxybiphenyl. In addition to the above aromatic dihydroxy compounds, hydroquinone, resorcin, etc. are also used. You may use these individually or in mixture of 2 or more types. The aromatic dihydroxy compound used particularly preferably in the present invention is bisphenol A.

The alkali metal or alkaline earth metal base (hereinafter abbreviated as base) used in the present invention is an alkali metal or alkaline earth metal hydroxide such as sodium hydroxide, potassium hydroxide or calcium hydroxide. From the viewpoint of easy availability, sodium hydroxide and potassium hydroxide are preferable, and sodium hydroxide is particularly preferable.

The amount of the base used is preferably about 1.0 to 1.5 times, and more preferably about 1.25 to 1.45 times the equivalent of the aromatic dihydroxy compound. The base is usually used in the form of an aqueous solution, but it is preferable to dissolve the aromatic dihydroxy compound in this aqueous solution and use it in the reaction. A basic aqueous solution of an aromatic dihydroxy compound,
Generally, since it is easily colored, it may be prepared by adding a reducing agent such as sodium sulfite, hydrosulfite, or sodium borohydride as an antioxidant.

As the water for preparing the basic aqueous solution of the aromatic dihydroxy compound, distilled water, ion-exchanged water or the like may be used, but in the present invention, the washing water or the reaction obtained when the aromatic polycarbonate is produced is used. Water can be used as it is or as a mixture with other water. When using reaction water or washing water, the concentration of the inorganic salt in the water is 0.3 to 0.3 with respect to the aromatic dihydroxy compound.
If it is 20% by weight, there is no problem, and even when considering the solubility of the aromatic dihydroxy compound in water, 0.3 to
If it is 15% by weight, there is no problem.

As the inorganic salt, sodium chloride, sodium bromide, sodium iodide, sodium carbonate, sodium hydrogen carbonate, potassium chloride, potassium bromide, potassium iodide, potassium carbonate, potassium hydrogen carbonate, potassium sodium carbonate, chloride Calcium, calcium carbonate,
Examples thereof include alkali metal or alkaline earth metal hydrochlorides or carbonates such as calcium hydrogen carbonate. Usually, it is a salt that is by-produced in a large amount during the process of producing an aromatic polycarbonate, such as sodium chloride or potassium chloride.

The presence of an inorganic salt in the reaction water beforehand means that
No influence is exerted on the hydrolysis amount of carbonyl halide during the reaction, the average molecular weight of the aromatic polycarbonate oligomer produced, and the residual amount and the average molecular weight of the unreacted end groups of the aromatic polycarbonate produced by the polymerization of the oligomer. Don't give. However, when 20% by weight or more of the inorganic salt is present in the reaction water with respect to the aromatic dihydroxy compound, the solubility of the aromatic dihydroxy compound is significantly reduced. Since the reaction must be carried out at 1, the aromatic polycarbonate having a wide molecular weight distribution tends to be produced.

The amount of water used to prepare the aqueous solution containing the aromatic dihydroxy compound is about 1.0-1.
It is the minimum amount necessary for the aromatic dihydroxy compound to be completely dissolved in the presence of 5 times the equivalent amount of the base. When the amount of water is less than this amount, the aromatic dihydroxy compound is not completely dissolved and the aromatic dihydroxy compound in the solid state is dissolved during the phosgenation reaction, so that an aromatic polycarbonate having a wide molecular weight distribution is obtained. Tend to be In addition, the aromatic dihydroxy compound in the solid state is scattered in the reaction tank and is dissolved after being heated, which causes coloring of the aromatic polycarbonate. On the other hand, an excessively large amount of water causes hydrolysis of phosgene and also industrially reduces productivity. The preferable amount of water used is about 0.8 to 2.2 liters, and particularly preferably 0.9 to 1.7 liters per mole of the aromatic dihydroxy compound.

The molecular weight modifier (also referred to as a terminal blocking agent) used in the present invention is for adjusting the final molecular weight in the process of producing an aromatic polycarbonate. Usually 1
Although a monovalent hydroxyaromatic compound is used, a monovalent hydroxyaromatic compound chloroformate compound, a monovalent carboxylic acid group-containing compound, a monovalent carboxylic acid chloride compound, or the like may also be used. Good. Examples of the monovalent hydroxyaromatic compound include phenol, p-tertiarybutylphenol, o-cresol, m-cresol, p-cresol, o-ethylphenol, m-ethylphenol, p-ethylphenol and o-quan. Millphenol, m-cumylphenol, p
-Cumylphenol, o-cyclohexylphenol,
m-cyclohexylphenol, p-cyclohexylphenol, o-octylphenol, m-octylphenol, p-octylphenol, o-nonylphenol, m-nonylphenol, p-nonylphenol, o
-Methoxyphenol, m-methoxyphenol, p-
Methoxyphenol, o-chlorophenol, m-chlorophenol, p-chlorophenol, o-bromophenol, m-bromophenol, p-bromophenol, pentabromophenol, pentachlorophenol, β-naphthol, α-naphthol, etc. is there.

Examples of the monovalent hydroxyaromatic compound chloroformate compound include the above-mentioned monovalent hydroxyaromatic compound chloroformate derivatives. Examples of the compound having a monovalent carboxylic acid group include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, heptanoic acid,
Caprylic acid, 2,2-dimethylpropionic acid, 3-methylbutyric acid, 3,3-dimethylbutyric acid, 4-methylvaleric acid,
3,3-dimethylvaleric acid, 4-methylcaproic acid, 2,
4-Dimethylvaleric acid, 3,5-dimethylcaproic acid, fatty acids such as phenoxyacetic acid, p-propoxybenzoic acid, p
-Butoxybenzoic acid, p-pentyloxybenzoic acid, p
Benzoic acids such as hexyloxybenzoic acid and p-octyloxybenzoic acid. Examples of the monovalent carboxylic acid chloride compound include chloride derivatives of the above-mentioned compounds having a monovalent carboxylic acid group. These alone,
Alternatively, two or more kinds are mixed and used. Phenol or p-tert-butylphenol is preferable because of easy availability.

The amount of the molecular weight modifier used in the method of the present invention is determined depending on the desired final molecular weight of the aromatic polycarbonate. A number average molecular weight of about 12,000 to 30,000 is preferable in order to exhibit various physical properties such as moldability, thermal decomposition resistance, and impact resistance of the aromatic polycarbonate. The amount of the molecular weight modifier necessary for producing the aromatic polycarbonate having the number average molecular weight in the above range is preferably 2.0 to 6.0 mol% with respect to the amount of the aromatic dihydroxy compound used.

In the embodiment of the present invention, the molecular weight modifier may be added in either the first tank or the intermediate tank in a plurality of connected tank type reactors through which the reaction solution flows. When adding the molecular weight modifier from the first tank, as the addition method, a method of dissolving it in an organic solvent at a predetermined concentration and adding it to the reaction system together with the supply of the organic solvent, or an alkali metal or alkaline earth metal of an aromatic dihydroxy compound It is possible to select a method in which it is dissolved in a metal base aqueous solution at a predetermined concentration and added to the reaction system together with the supply of the aqueous solution, or a method in which it is individually added as an organic solvent solution or an alkali metal or alkaline earth metal base aqueous solution. When the molecular weight modifier is added from the intermediate tank, it is a method of individually adding it as an organic solvent solution or an alkali metal or alkaline earth metal base aqueous solution.

The molar ratio of molecular weight regulator to aromatic dihydroxy compound affects the reproducibility of the molecular weight of the product.
Therefore, as a method for adding the molecular weight modifier, a method of dissolving the aromatic dihydroxy compound in an alkali metal or alkaline earth metal base aqueous solution at a predetermined concentration and supplying the solution is preferable because the molar ratio does not change, but if necessary, When individually supplying as an organic solvent solution or an alkali metal or alkaline earth metal base aqueous solution from the first tank or an intermediate tank, supply the organic solvent solution of the molecular weight regulator or the alkali metal or alkaline earth metal base aqueous solution. Reproduction of the molecular weight of the product by controlling the flow rate as a set value that is obtained by multiplying the supply flow rate of the alkali metal or alkaline earth metal base aqueous solution of the aromatic dihydroxy compound controlled by the method of the invention by the set value. It will be possible to drive without any problems.

The polymerization catalyst used in the present invention is a tertiary amine,
Examples thereof include quaternary ammonium salts, tertiary phosphines, quaternary phosphonium salts, nitrogen-containing heterocyclic compounds and salts thereof, imino ethers and salts thereof, and compounds having an amide group. Preferably, it is a trialkylamine which is a tertiary amine, more preferably on the carbon atom at the 1-position and 2-position such as triethylamine, tri-n-propylamine, diethyl-n-propylamine, tri-n-butylamine and the like. Is a trialkylamine having an alkyl group of C1 to C4 without branching. Triethylamine is particularly preferable in terms of easy availability and excellent catalytic effect.

The method for adding the polymerization catalyst in the embodiment of the present invention is to dissolve it in an organic solvent at a predetermined concentration and add it to the reaction system together with the supply of the organic solvent, or to add an alkali metal or alkaline earth metal of an aromatic dihydroxy compound. A method of dissolving it in a metal base aqueous solution at a predetermined concentration and adding it to the reaction system together with the supply of the solution, or a method of individually adding it as an organic solvent solution or an aqueous solution can be selected. The amount of the polymerization catalyst used at that time is determined within a range that satisfies the following equation with the residence time in the first tank.

## EQU3 ## logy <-2.19x + 1.84 (x ≧ 0.0005, y ≧ 1,0.5 ≦ xy) x: catalytic amount (mol% based on aromatic dihydroxy compound) y: residence time in first tank (Minutes)

The catalyst amount changes according to the residence time in the first tank, as defined by the relational expression. For example, when the residence time in the first tank is 5 minutes, a suitable catalyst amount range is 0.0005 mol% or more and 0.52 or more with respect to the aromatic dihydroxy compound.
It will be less than mol%. Also, for example, the residence time of the first tank is 2
When it is 5 minutes, the suitable catalyst amount range is 0.0005 mol% or more and less than 0.20 mol% with respect to the aromatic dihydroxy compound, and when the residence time in the first tank is 50 minutes, the suitable catalyst amount is The amount range is 0.0005 mol% or more and less than 0.06 mol% with respect to the aromatic dihydroxy compound. However, if the combined conditions of the amount of catalyst and the residence time in the first tank are out of the prescribed formula, the reproducibility of the molecular weight and quality of the product will be impaired, which is not preferable. To measure the alkali metal or alkaline earth metal base concentration of the aromatic dihydroxy compound in the aqueous phase extracted from the first tank, and to make a quick response to the controlled amount of raw material supply in accordance with the reaction conditions, Within the range defined in, the residence time in the first tank is preferably 3 minutes to 30 minutes, and most preferably 5 minutes to 15 minutes. If the residence time in the first tank is extremely short, the initial contact of the raw materials tends to be insufficient, and the operation control of the present invention may not be effective for the reproducibility of the molecular weight and quality of the product, which is not preferable.
In addition, the longer the retention time in the first tank, the longer the delay time for the correction operation when an abnormal operation occurs, which is not preferable.

When the initial contact between the aromatic dihydroxy compound and the carbonyl halide compound in the first tank is carried out without a polymerization catalyst, the reaction speed of the initial contact is slowed down, so that the reaction between the aromatic dihydroxy compound and the carbonyl halide compound occurs. Since the fluctuation of the amount of unreacted aromatic dihydroxy compound contained in the aqueous phase extracted from the first tank becomes dull with respect to the fluctuation of the molar ratio, the situation of the reaction molar ratio of the initial contact should be judged by this. Is difficult to do, which is not preferable. The use of excess polymerization catalyst not only hinders the present invention in that the residence time in the first tank must be set to an extremely short condition, but also adversely affects the reproducibility of the molecular weight distribution of the aromatic polycarbonate obtained. It is not preferable because it causes

Carbonyl halide is used as a raw material for forming a carbonate bond in the present invention.
For example, phosgene, carbonyl bromide, carbonyl iodide, carbonyl fluoride and the like, and a mixture thereof may be used. Further, it may be a compound having the ability to form a haloformate group, for example, trichloromethylchloroformate which is a dimer of phosgene, bis (trichloromethyl) carbonate which is a trimer of phosgene, and the like. Usually, it is preferable to use phosgene. The amount of the carbonyl halide used in producing the aromatic polycarbonate in the present invention is adjusted to be about 1.0 to 1.3 times the molar amount of the aromatic dihydroxy compound. To maintain more stable continuous operation, 1.15 to 1.25 times mol, more preferably 1.18
It is better to adjust to a range of ˜1.23 times mole. If the amount of the carbonyl halide used is extremely less than about 1.0 times the amount of the aromatic dihydroxy compound or is excessively more than 1.3 times the amount of the aromatic dihydroxy compound, a product having a target molecular weight and quality is obtained. Is not preferable because it cannot be obtained.

The carbonyl halide may be supplied in the form of gas, liquid or solution. It is preferable to supply in a gas state, but it may be supplied in a state of an organic solvent solution dissolved in an organic solvent such as dichloromethane. Further, in order to stably and constantly supply carbonyl halide, it may be preferable that the carbonyl halide supplied to the first tank reactor is in a state of an organic solvent solution. When supplying the carbonyl halide as an organic solvent solution, the carbonyl halide and the organic solvent may be mixed in advance to prepare an organic solvent solution, and the organic solvent solution may be continuously supplied. In front of the above, the carbonyl halide and the organic solvent may be continuously brought into contact with each other using a device such as a pipe or a gas absorption device to continuously prepare an organic solvent solution of the carbonyl halide. After mixing the carbonyl halide and the organic solvent, in the case of producing an aromatic polycarbonate by supplying to the tank reactor, it is necessary that the polymerization catalyst does not exist in the organic solvent, When the organic solvent is separately supplied, and when the organic solvent is supplied after the carbonyl halide is brought into contact with the aqueous reaction solution, even if the polymerization catalyst within the preferable range described above is present in the organic solvent. Good.

The alkali metal or alkaline earth metal base aqueous solution of the aromatic dihydroxy compound and the carbonyl halide are supplied by setting them so that the molar ratio of the two raw materials described above is within a suitable range. Is measured, and normal control for adjusting the opening / closing degree of the raw material supply valve is performed.
Meters used to measure the flow rate include differential pressure flowmeters such as orifices, nozzles and venturis, area type flowmeters of float type, positive displacement type flowmeters of piston type and rotary piston type, turbine type flowmeters, gyroscopes. Type and axial flow type mass flow meters are used.

Any organic solvent can be used as long as it is substantially insoluble in water, inert to the reaction, and capable of dissolving the aromatic polycarbonate. For example, dichloromethane, chloroform, 1,2-
It is preferable to use aliphatic chlorinated compounds such as dichloroethane, 1,2-dichloroethylene, trichloroethane, tetrachloroethane, dichloropropane, or a mixture thereof. Further, an organic solvent in which an aromatic hydrocarbon such as toluene, xylene and ethylbenzene, an aliphatic hydrocarbon such as hexane, heptane and cyclohexane are mixed with chlorinated hydrocarbons and a mixture thereof may be used. Particularly preferred is dichloromethane. Further, in the present invention, the recovery solvent produced when the aromatic polycarbonate produced by the method of the present invention is recovered can be used as it is or as a mixture with a new organic solvent.

The amount of the organic solvent used is determined so that the viscosity of the organic phase during the polymerization reaction does not always exceed 300 centipoise (cps). By satisfying this condition, the steady-state of the reaction is promptly and stably ensured, so that the molecular weight and the molecular weight distribution of the aromatic polycarbonate recovered from the reaction mixture continuously withdrawn from the last tank reactor are determined. Control is performed with good reproducibility from beginning to end. Viscosity of organic phase is 300
If it exceeds cps, the reaction efficiency becomes slow due to a decrease in stirring efficiency, and a long polymerization time is required. Therefore, it is necessary to increase the scale of the tank-type reactor for polymerization and increase the number of tanks. Furthermore, the molecular weight of the final product becomes uncontrollable. The viscosity of 300 cps at room temperature means that when the target number average molecular weight of the aromatic polycarbonate is 20000, the concentration of the aromatic polycarbonate in the organic solvent solution at the end of the polymerization is about 15% by weight. When the number average molecular weight of the aromatic polycarbonate is 30,000, the amount of the organic solvent is such that the concentration of the aromatic polycarbonate in the organic solvent solution at the end of the polymerization is about 12% by weight.

The amount of the organic solvent used is influenced by the amount of water used in the reaction, but the amount of the organic solvent in the initial stage of the reaction is usually 0.
It is preferably 8 to 1.2: 1. The present inventors have reacted with an aqueous solution of an alkali metal or alkaline earth metal base of an aromatic dihydroxy compound with a carbonyl halide in the presence of a polymerization catalyst to produce an aromatic polycarbonate, and an organic solvent and water. As a result of examining the volume ratio of the phases, it was found that when the volume ratio is within the above range, it is possible to effectively reduce the hydrolysis amount of the carbonyl halide, which has been difficult in the conventional tank reactor. It was Furthermore, it has been found that when the aromatic polycarbonate is produced with a solvent amount ratio limited within the above range, the polymerization is completed very quickly. When the amount of solvent is within the above range, since complete mixing is efficiently performed, it is possible to stably produce an aromatic polycarbonate oligomer and aromatic polycarbonate, and when the amount of solvent is outside the above range, In comparison, uniform emulsification is possible with less stirring power. When the organic solvent is less than the above range, a large amount of stirring power is required to form a uniform emulsified state, and when the amount of the organic solvent is more than the above range, a larger stirring power is required. Since it is necessary, it is not preferable in terms of production cost.

In the method of the present invention, about 10 to 50 ° C.
Reaction temperatures of are used. If the reaction temperature is lower than 10 ° C, the reaction rate becomes too slow, which is not practical.
Further, at a reaction temperature higher than 50 ° C., the solubility of the carbonyl halide in an organic solvent is lowered, so that preferable reaction efficiency may not be obtained, and the carbonyl halide and / or the haloformate compound derived therefrom may not be hydrolyzed. The decomposition reaction is also accelerated, which is not preferable. When the organic solvent used is dichloromethane, it can be carried out at a reflux temperature of about 39 ° C. under atmospheric pressure. The reaction pressure is usually atmospheric pressure, but if desired, pressure conditions below atmospheric pressure and above atmospheric pressure are also used.
The concentration of the alkali metal or alkaline earth metal base of the aromatic dihydroxy compound in the aqueous phase extracted from the first tank may vary depending on the reaction temperature, but the range of the concentration set in the present invention is greatly deviated, Unless there is a rapid temperature change that disturbs the control of the feed rate of the raw material, the change in the reaction temperature within the above temperature range is a disturbance that can be handled by the effect of the present invention. And does not affect the reproducibility of the quality and does not require control to a particular reaction temperature.

In the present invention, the reaction mixture consisting of the organic phase in which the aromatic polycarbonate is dissolved and the aqueous phase is continuously withdrawn from the tank reactor, but this withdrawal method can be selected arbitrarily. . For example, overflow, withdrawal with a pump, or withdrawal from the bottom or side of the reaction tank with a pump, return to another position in the reaction tank, and circulate, while supplying the same amount to the reaction tank at any position of the pipe. A quantity of the reaction mixture may be withdrawn. In addition, the extraction position is provided at the bottom of the tank-type reactor, and the reaction mixture is extracted quasi-continuously, that is, intermittently at extremely short intervals, or the reaction mixture is controlled while controlling the flow rate with the control valve. It also includes continuous withdrawal from the bottom or intermediate position of the.

The stirring during the reaction may use any stirring device and stirring conditions, but extremely fast stirring promotes the hydrolysis of the carbonyl halide or the haloformate group derived therefrom. become. Further, when the stirring speed is extremely slow, the contact area at the interface is reduced, and the reaction under the interface conditions does not proceed well. The preferable stirring speed cannot be indicated only by the number of revolutions because it depends on the shape of the polymerization tank in which the reaction is performed, the shape of the stirring blade, and the like. The preferable stirring speed can be determined by a simple experiment, but usually, the stirring speed is such that the organic solvent phase and the aqueous phase are mixed almost uniformly.

An embodiment of the present invention will be described. First, a mixture of an aromatic dihydroxy compound, a base, a polymerization catalyst, a molecular weight modifier, water, and optionally a branching agent and an antioxidant is prepared. At this time, the temperature at which the aromatic dihydroxy compound is dissolved is preferably 20 ° C. or lower in order to prevent coloration during the dissolution of the aromatic dihydroxy compound. Polymerization catalyst without adding to the aqueous phase of this raw material,
A method of adding in the middle or the final stage of the connected polymerization reaction tank may be used. This preparation may be carried out batchwise at any time, but preferably it is prepared continuously and the prepared mixture is used continuously. The water used at this time is reaction water containing a small amount of the polymerization catalyst used when producing the aromatic polycarbonate oligomer or the aromatic polycarbonate, or washing water, and the inorganic salt in the water is 0.3 to 20.
It is possible to use water that has been appropriately concentrated and diluted so as to have a weight percentage.

Next, this mixture, the carbonyl halide and the organic solvent are respectively supplied to the first tank reactor. As this supply method, a method of supplying or dropping below the liquid surface or above the liquid surface by optionally separate pipes may be adopted, and the carbonyl halide and the organic solvent are arbitrarily mixed and then supplied. You may. The ratio of the supplied amount is preferably within the range of the used amount described above.
That is, the carbonyl halide is about 1.0 to 1.3 times mol per unit time with respect to the aromatic dihydroxy compound, and the amount of the organic solvent is about 0.8 by volume ratio with respect to water in the aqueous base solution. It is preferable to supply it so that it is about 1.2: 1. The overall supply rate is controlled so that the residence time of the reaction mixture in the first tank reactor is in a suitable relationship with the amount of catalyst. Basically, the residence time in the first tank can be arbitrarily selected within a suitable range of the relationship with the amount of the catalyst according to the stipulated formula, but 3 to 30 minutes are preferable as a manufacturing condition in which the response of the correction operation in the control operation is fast And more preferably 5 to 15 minutes.

The supply amount of the alkali metal or alkaline earth metal base aqueous solution of the aromatic dihydroxy compound and the carbonyl halide compound is determined from the set value with respect to the flow rate determined in consideration of the concentration of each raw material and the supply amount ratio. The deviation is measured to control. These controls need only be such that the error of the actual flow rate with respect to the set value is kept within 2%. By controlling the supply flow rate, the reproducibility of the molecular weight of the product is achieved to some extent, but when the concentration change or pressure change of the raw material solution or gas occurs, the flow rate control can prevent the fluctuation of the reaction molar ratio. It ’s gone
The molecular weight of the product obtained by continuous operation will vary little by little. Therefore, the operation of analyzing the state of the reaction system, correctly grasping the current supply molar ratio of the alkali metal or alkaline earth metal base aqueous solution of the aromatic dihydroxy compound and the carbonyl halide compound, and adjusting the supply flow rate based on this Is added.

Specifically, the alkali metal or alkaline earth metal base concentration of the aromatic dihydroxy compound in the aqueous phase intermittently withdrawn from the first tank is measured and the residual ratio ( b:%), and from this the correction ratio (a) is calculated according to the formula defined in the claims, and this is multiplied by the set value of the flow rate of the alkali metal or alkaline earth metal base aqueous solution of the aromatic dihydroxy compound. The flow rate is controlled by the set value that is changed at any time. The alkali metal or alkaline earth metal base concentration of the aromatic dihydroxy compound in the aqueous phase extracted from the first tank is measured by a titration method or high performance liquid chromatography. The measurement interval may be a time within 3 times the residence time in the first tank, and particularly preferably 1 / the residence time in the first tank.
About 2 to 2 times is good. If this interval is too large, it becomes difficult to cancel the influence of disturbance between corrections, and the correction effect is not reflected in the reproducibility of the product molecular weight, which is not preferable.

Next, the aromatic polycarbonate is continuously prepared from a heterogeneous mixture of the organic solvent solution containing the aromatic polycarbonate oligomer in the first tank reactor and the aqueous phase containing the unreacted aromatic dihydroxy compound. For production, the polymerization reaction is carried out in at least one tank reactor connected to the first tank reactor. Preferably,
It is preferable to carry out the polymerization by using a tank reactor for polymerization of 2 to 4 tanks and a residence time of about twice or more the residence time in the first tank reactor for producing the aromatic polycarbonate oligomer. Polymerization is accomplished by completely reacting the haloformate end groups of the aromatic polycarbonate oligomer with the OH end groups of the unreacted aromatic dihydroxy compound. The residence time of this polymerization depends on the emulsified state of the reaction system,
That is, although depending on the stirring speed and the like, the total residence time is about several minutes to about 1 hour and 30 minutes, and usually about 10 minutes to 60 minutes is sufficient. Further, preferably, a continuous tank reactor having 2 to 4 tanks is used to carry out the polymerization for each residence time within the above range. If the polymerization time is too long, the tank reactor for polymerization is required to be large in size, the equipment cost is high, and sometimes the carbonate bond of the aromatic polycarbonate is broken.

The organic solvent solution of the aromatic polycarbonate thus produced is neutralized with an acid and then washed with water repeatedly until the electrolyte is substantially absent. Then, the organic solvent can be removed from the solution of the aromatic polycarbonate in an organic solvent by a known method to obtain an aromatic polycarbonate. Furthermore, in the method for producing a polycarbonate of the present invention, at any point in the reaction, heat stability during processing of an aromatic polycarbonate, light resistance, weather resistance, flame retardancy, and the like for the purpose of imparting other properties, are known. It is possible to add additives for the aromatic polycarbonates of. Known additives include processing and heat stabilizers, antioxidants, ultraviolet absorbers, mold release agents, organic halogen compounds, alkali metal sulfonates, glass fibers, glass beads, barium sulfate, TiO 2.
It is ₂ mag.

[0048]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples. The values of the number average molecular weight (Mn) and the weight average molecular weight (Mw) used in the examples are G manufactured by Showa Denko KK
It was calculated in terms of polystyrene from a chromatogram obtained by measuring with a chloroform solvent using a polystyrene gel column by PC SYSTEM-11 and using an RI detector, and the polydispersity index (Mw / Mn) was calculated from the value. ) Was asked. The alkali metal or alkaline earth metal base concentration of the aromatic dihydroxy compound in the aqueous phase extracted from the first tank, that is, the amount of residual bisphenol A in the examples, is the octadecyl group-modified synthetic polymer in the stationary phase, and the fluid phase. The aqueous phase was directly analyzed by reverse phase high performance liquid chromatography using a mixed solution of acetonitrile / water = 4/1, and calculated from the chromatogram obtained with a UV detector (284 nm). The melt viscosity of the product is measured by using a melt indexer manufactured by Toyo Seiki Co., Ltd. according to JIS K-721.
According to the method of No. 0, when the load of 2.16 kg was applied at 280 ° C., the weight of the resin extruded from the die in 10 minutes was evaluated.

Example 1 225 kg (985.6 mol) of bisphenol A and p-tert-butylphenol as a molecular weight regulator 4.
678 kg (31.14 mol), triethylamine 0.
10 kg (0.988 mol), 28% caustic soda water 41
7 kg (2919 mol), 0.451 kg of sodium hydrosulfite, and 1228 kg of water were charged into a dissolution tank, and stirred to uniformly dissolve them to give a total weight of 1875.2.
A 29 kg aqueous mixture was prepared. The set values of the supply amount of this aqueous mixture, phosgene, and organic solvent are set to 71.6 each.
kg / hr, 4.5 kg (45.46 mol) / hr, 6
The flow rate was set to 1.5 kg / hr, and the flow rate was measured with a differential pressure flow meter using an orifice, and while controlling the flow rate, it was supplied to a 50-liter first tank reactor. The residence time was 20 minutes.
A portion of the continuously discharged reaction mixture is withdrawn every 20 minutes, and the Na salt of bisphenol A remaining in the aqueous phase is quantified, and the correction ratio obtained from the result is used as the set value of the supply flow rate of the aqueous mixture. By repeating this, the operation was performed while changing the set value of the supply flow rate of the water-based mixed solution every 20 minutes until the end of the operation. The reaction liquid flowing out from the first tank type reactor was supplied to a second tank type reactor of 150 liters through a pipe, polymerization was carried out for a residence time of 60 minutes, and the reaction mixture was added to a third tank of 150 liters. Supply to the tank reactor of
Polymerization was carried out with a residence time of 60 minutes. The reaction mixture continuously discharged from the third tank reactor was immediately separated,
It was neutralized with hydrochloric acid. The obtained organic phase was washed with pure water until the electrolyte was exhausted. The organic solvent was evaporated from the organic solvent solution containing this aromatic polycarbonate to obtain a solid aromatic polycarbonate. This continuous operation was performed for 26 hours, and the molecular weight of the obtained aromatic polycarbonate was analyzed every hour. The results are shown in Table 1. Thus, according to the method of the present invention, it was possible to rapidly respond to changes in the situation during long-term continuous operation, and to extremely stably manufacture a product having a target molecular weight. The products obtained continuously in this way have extremely uniform melt viscosities at any operating time, and it is possible to supply products that can be stably molded.

Example 2 By the same operation as in Example 1, initially the reaction was started in the same manner as in Example 1 with the supply amounts thereof. When this continuous operation was performed for 8 hours, the phosgene supply amount setting was changed to 4.3 kg (43.44 mol) / hr for 40 minutes to create a situation in which phosgene was insufficient than the set amount, and then 4.5 kg.
The operation was continued by returning to / hr. And in addition, driving 16
From the hour, set the supply amount of phosgene to 4.7k for 40 minutes.
Change to g (47.48 mol) / hr to create a situation where phosgene is in excess of the set amount, then 4.5 kg / h
The operation was continued by returning to r. The molecular weight of the finally purified and isolated aromatic polycarbonate was analyzed every hour. N of bisphenol A in the aqueous phase flowing out from the first tank
Table 2 shows the quantitative results of the salt a, that is, the residual ratio (b), the correction ratio (a), the change in the set flow rate of the raw material, and the change over time in the molecular weight. Thus, even if the feed amount of phosgene is intentionally changed on the assumption that the raw material feed molar ratio is changed, the control of the method of the present invention quickly corrects it,
A product having a target molecular weight could be manufactured extremely stably. This shows that the control of the method of the present invention is effective against accidental changes in the raw material supply rate.

Comparative Example 1 Only the method of measuring the flow rate of each raw material without controlling the method of the present invention and controlling it according to the deviation from the set value was used.
The same scale continuous operation was performed. Table 3 shows the results of analyzing the molecular weight of the aromatic polycarbonate finally purified and isolated every hour. When the control of the method of the present invention was not performed, the molecular weight of the product obtained varied with time and was inferior in reproducibility. This is influenced by the change in the raw material supply molar ratio, which cannot be compensated for only by controlling the flow rate. The melt viscosity also varies depending on the operating hours,
A width of 7.8 to 11.2 g / min was produced. This is equivalent to the difference in viscosity between a medium viscosity product and a low viscosity product for aromatic polycarbonate grades, and it is possible to produce molded products with reproducibility even if molding with this product is performed under certain conditions. Can not.

[0052]

[Table 1]

[0053]

[Table 2]

[0054]

[Table 3]

[0055]

[Table 4]

[0056]

EFFECTS OF THE INVENTION It is possible to quickly respond to changes in the reaction situation due to various disturbances, perform accurate control that is important in reproducibility of product quality, and achieve stable continuous operation, resulting in excellent reproducibility of molecular weight. , It is possible to continuously and efficiently produce aromatic polycarbonate with uniform mechanical and thermal properties and melt flowability on an industrial scale, and perform molding processing for precision molded products with good reproducibility. be able to.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shoji Obuchi 30 Asamu-cho, Omuta City, Fukuoka Prefecture Mitsui Toatsu Chemical Co., Ltd. (72) Masahiro Ota 30 Asamu-cho, Omuta City, Fukuoka Mitsui Toatsu Inside Chemical Co., Ltd.

Claims (2)

[Claims] 1. A tank reactor in which a plurality of alkali metal or alkaline earth metal base aqueous solution of at least one aromatic dihydroxy compound and a carbonyl halide compound are connected together with a polymerization catalyst, a molecular weight modifier and an organic solvent. In the method for producing an aromatic polycarbonate by continuously supplying and reacting with an alkali metal or alkaline earth metal base aqueous solution of an aromatic dihydroxy compound and the supply of the carbonyl halide compound, the deviation of the flow rate from the set value is measured. The concentration of the alkali metal or alkaline earth metal base of the aromatic dihydroxy compound in the aqueous phase extracted from the first tank is measured, and the residual ratio is calculated with respect to the concentration of the supply liquid. A correction ratio is derived according to the deviation from the standard value, and this is used as the alkali metal of the aromatic dihydroxy compound. Alternatively, the method for producing an aromatic polycarbonate is characterized by multiplying the set flow rate of the alkaline earth metal base aqueous solution and correcting the supply amount at any time. 2. The correction ratio (a) for the controlled flow rate of an alkali metal or alkaline earth metal base aqueous solution of an aromatic dihydroxy compound is extracted from the first tank of a plurality of connected tank reactors during the reaction. The aromatic polycarbonate according to claim 1, which is obtained by the following equation, based on the residual ratio (b:%) calculated from the concentration of the alkali metal or alkaline earth metal base of the aromatic dihydroxy compound in the aqueous phase. Production method. ## EQU1 ## a = -0.018 * (b-11.5) +0.99 ... [13 <b] a = -0.022 * (b-11.5) +1.00 ... [10≤b≤ 13] a = −0.003 × (b-11.5) +1.03 ... [b <10] However, the catalyst amount (x: mol% relative to the aromatic dihydroxy compound) and the residence time in the first tank (y: Min) applies under the following conditions. logy <−2.19x + 1.84 [x ≧ 0.0005, y ≧ 1, xy ≧ 0.5]