KR20080082958A - Process for continuous production of polycarbonate oligomer - Google Patents

Abstract

The object is to provide a process for continuously producing a polycarbonate oligomer in a simple facility, at low cost, and with good productivity. Disclosed is a process for continuously producing a polycarbonate oligomer by reacting an aqueous alkaline solution (ii) of a dihydric phenol compound with a phosgene gas (iii) in the presence of an organic solvent (i). The process comprises the steps of: (1) reacting chlorine with carbon monooxide at a molar ratio of 1:1.01-1.3 to yield a phosgene gas (iii) having a carbon monooxide content of 1-30% by volume; (2) reacting an organic solvent (i), an aqueous alkaline solution (ii) of a dihydric phenol compound and the phosgene gas (iii) continuously to yield an initial-stage product having a gas/liquid mixed phase; (3) cooling the initial-stage product to 2-25°C; and (4) subjecting the initial-stage product to gas/liquid separation to yield a product solution containing a polycarbonate oligomer.

Description

Continuous production method of polycarbonate oligomer {PROCESS FOR CONTINUOUS PRODUCTION OF POLYCARBONATE OLIGOMER}

TECHNICAL FIELD This invention relates to the continuous manufacturing method of a polycarbonate oligomer, and the manufacturing method of the high quality polycarbonate resin which uses this polycarbonate oligomer as a raw material.

As a manufacturing method of a polycarbonate oligomer, the method of making the alkali aqueous solution of a dihydric phenol compound and phosgene react in presence of an organic solvent and manufacturing is known. In this method, since the reaction proceeds rapidly, it is necessary to pay attention to the removal of the heat of reaction and the prevention of local heating, and various improvements have been proposed for these improvements.

For example, Patent Document 1 proposes a method of continuously producing a polycarbonate resin by reacting a gas phase containing a liquid phase, a liquid organic phase, and phosgene in a reactor having a packing. This method is characterized by removing the heat of reaction by using a large amount of inert gas. However, in order to lower the reaction temperature to about 30 ° C, a large amount of inert gas is required, and a large-capacity gas-liquid separator is required. In addition, the process is complicated and economically disadvantageous. In addition, there is a drawback that if the production amount is adjusted by a reactor having packed column water, the variation in the quality of the oligomer and polymer obtained is large.

Patent Literature 2 discloses an aqueous alkali solution of bisphenol A and methylene chloride in a tubular reactor, and when a phosgene is co-reacted thereto, 1 to 10 mol% of an inert gas is added to the tubular reactor with phosgene. Methods for preparing polycarbonate oligomers by introducing them into are described. However, this method has a low reaction rate and high decomposition rate of phosgene. There is also a drawback that the variation in the quality of the oligomer and polymer obtained is large.

Patent Document 3 describes a method of continuously producing a polycarbonate oligomer using a tubular reactor in which an aqueous alkali solution and a phosgene of a dioxy compound are kept in a temperature range of 2 to 20 ° C. in the presence of an organic solvent. This method is characterized by removing the heat of reaction by increasing the ratio of tube length and tube diameter. This method is effective when production is low. However, if the yield increases, it is difficult to remove the heat of reaction unless the ratio between the tube length and the tube diameter is made very large. Therefore, in this method, the variation of the quality of the oligomer and polymer obtained becomes large with the fluctuation | variation of the yield.

On the other hand, Patent Document 4 exemplifies a method of continuously producing a polycarbonate oligomer using liquefied phosgene. However, the method of using liquefied phosgene must store a certain amount of highly toxic phosgene in the process. This method also requires an apparatus for cooling and liquefying phosgene gas.

(Patent Document 1) Japanese Unexamined Patent Publication No. 47-014297

(Patent Document 2) Japanese Patent Publication No. 56-044091

(Patent Document 3) Japanese Unexamined Patent Publication No. 58-108225

(Patent Document 4) Japanese Patent Publication No. 54-040280

Disclosure of the Invention

An object of the present invention is to provide a method for use in producing a polycarbonate oligomer as it is without liquefying phosgene gas obtained by reacting carbon monoxide and chlorine.

It is an object of the present invention to provide a process for continuously producing polycarbonate oligomers at low cost and with good productivity in a simple facility.

The present inventors examined a method of producing a polycarbonate oligomer by reacting an aqueous alkali solution (ii) of a dihydric phenol compound with phosgene gas (VII) in the presence of an organic solvent (VII).

As a result, when phosgene gas is reacted with chlorine and carbon monoxide at a ratio of 1.01 to 1.3 moles of carbon monoxide with respect to 1 mole of chlorine, there is less unreacted chlorine when phosgene gas containing 1 to 30 vol% of carbon monoxide is used. It was also found that gas-liquid separation after the reaction can be easily performed.

In addition, it was found that the reaction of the gas-liquid can be carried out efficiently by carrying out the reaction in a stationary mixer.

In addition, it was found that by cooling the initial product obtained by the reaction to 2 to 25 ° C, side reactions of phosgene gas can be suppressed and polycarbonate oligomer can be efficiently produced. In addition, it was found that when the initial product cooling was brought into contact with a product solution obtained by cooling and gas-liquid separation, it was possible to rapidly cool, suppress side reactions of phosgene gas, and efficiently produce a polycarbonate oligomer.

It was also found that by circulating the product solution upstream of the reactor, control of the reaction temperature and control of the yield were facilitated.

It was also found that polycarbonate resins prepared using polycarbonate oligomers are of good quality.

That is, according to the present invention, as a method of continuously producing a polycarbonate oligomer by reacting an aqueous alkali solution (ii) of a dihydric phenol compound with phosgene gas (VIII) in the presence of an organic solvent (VIII),

(1) a step of reacting chlorine and carbon monoxide at a ratio of 1.01 to 1.3 mol of carbon monoxide with respect to 1 mol of chlorine to obtain a phosgene gas containing 1 to 30% by volume of carbon monoxide;

(2) a step of continuously reacting an organic solvent (iii), an aqueous alkali solution (ii) of the dihydric phenol compound and the obtained phosgene gas (iii) to obtain a gas-liquid mixed initial product,

(3) cooling the initial product to 2 to 25 ° C, and

(4) A method is provided, including the step of gas-liquid separating the initial product to obtain a product solution containing a polycarbonate oligomer.

Moreover, according to this invention, the method of manufacturing the polycarbonate resin of the viscosity average molecular weights 10,000-50,000 is further provided by superposing | polymerizing the polycarbonate oligomer in the obtained product solution.

1 is a flow sheet showing an example of a process for producing phosgene gas.

It is a flow sheet which shows an example of the manufacturing process of a polycarbonate oligomer.

Explanation of the sign

a: carbon monoxide supply pipe

b: chlorine supply pipe

c: mixer

d: reaction tower

e: gas flow meter

f: gas extraction pipe

g: gas duct

h: cooler

i: liquid phosgene reservoir

j: metering pump

k: carburetor

l: phosgene gas extraction pipe

m: gas extraction pipe

1 to 3: Alkali aqueous solution supply pipe, organic solvent supply pipe, or phosgene supply pipe of a dihydric phenol compound, each optionally

4: mixing reactor

5: mixing tank

6: circulation pump

7: cooler

8-1 and 8-2: circulation piping

9-1, 9-2, 9-3, 9-4 and 9-5: reaction liquid return piping

10: waste gas discharge pipe

11: first-generation product sphere

Implement the invention  Best form for

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The present invention is a method for continuously producing a polycarbonate oligomer by reacting an aqueous alkali solution of a dihydric phenol compound with phosgene in the presence of an organic solvent. The method includes the following steps (1) to (4).

Process (1)

Step (1) is a step of obtaining phosgene gas containing 1 to 30% by volume of carbon monoxide by reacting chlorine and carbon monoxide at a ratio of 1.01 to 1.3 mol of carbon monoxide with respect to 1 mol of chlorine.

Carbon monoxide is produced by reacting oxygen with coke, petroleum, natural gas, alcohol and the like, and is preferably purified at a purity of 95% by volume or more. In particular, it is preferable that content of a sulfur component is 50 ppm or less.

The reaction can be carried out, for example, by a known method described in JP-A-55-14044. Activated carbon can be used as a catalyst.

The ratio of chlorine and carbon monoxide is 1.01 to 1.3 mol of carbon monoxide with respect to 1 mol of chlorine, Preferably it is 1.02 to 1.2 mol with respect to 1 mol of chlorine.

When carbon monoxide is less than 1.01 mol with respect to 1 mol of chlorine, unreacted chlorine in phosgene gas increases, and since the quality of the polycarbonate oligomer obtained worsens, it is unpreferable. When the carbon monoxide exceeds 1.3 mol, the amount of carbon monoxide used increases, the raw unit of carbon monoxide decreases, the amount of phosgene accompanying carbon monoxide when gas-liquid separation increases, and the processing equipment is maximized and complicated, which is not preferable. not.

That is, the step (1) of obtaining phosgene gas is a step of reacting chlorine and carbon monoxide at a ratio of 1.02 to 1.2 mol of carbon monoxide with respect to 1 mol of chlorine, thereby obtaining a phosgene gas containing 2 to 20% by volume of carbon monoxide. It is preferable.

The phosgene gas contains 1 to 30% by volume of carbon monoxide, preferably 2 to 20% by volume. That is, it is phosgene gas of purity 99-70 volume%. The temperature of the phosgene gas used for reaction has the preferable boiling point (7.8 degreeC)-90 degreeC of phosgene.

In the present invention, the obtained phosgene gas is used for reaction as it is without cooling. Therefore, there is an advantage that energy used for cooling and vaporization is not necessary.

Process (2)

Step (2) is a step of continuously reacting an organic solvent (iii), an aqueous alkali solution (ii) of a dihydric phenol compound and a phosgene gas (iii) to obtain a gas-liquid mixed initial product.

As an organic solvent (i), the solvent which melt | dissolves a polycarbonate oligomer and polycarbonate resin is mentioned. Specifically, halogenated hydrocarbon solvents, such as dichloromethane (methylene chloride), dichloroethane, trichloroethane, tetrachloroethane, pentachloroethane, hexachloroethane, dichloroethylene, chlorobenzene, dichlorobenzene, are mentioned, Especially dichloromethane (Methylene chloride) is preferable. The range of temperature 0- (boiling point of organic solvent-5) degreeC of the organic solvent (i) provided for reaction is preferable.

As the dihydric phenol compound (ii), for example, hydroquinone, resorcin, 4,4-dihydroxydiphenyl, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenol) Ethane, 2,2-bis (4-hydroxyphenyl) propane (commonly known bisphenol A), 2,2-bis (3-methyl-4-hydroxyphenol) propane, 1,1-bis (4-hydroxyphenyl Cyclohexane (commonly known bisphenol Z), 2,2-bis (3-phenyl-4-hydroxyphenyl) propane, 2,2-bis (3-isopropyl-4-hydroxyphenyl) propane, 2,2- Bis (4-hydroxyphenyl) butane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, 2,2-bis (3,5-dibromo-4-hydroxyphenyl) Propane, 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxydiphenylsulfoxide, 4,4'-dihydroxydiphenylsulfide, 3,3'-dimethyl-4,4 '-Dihydroxydiphenylsulfide, 4,4'-dihydroxydiphenyloxide, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis {(4-hydroxy-3 -Methyl) phenyl} fluorene, α, α'-bis (4- Hydroxyphenyl) -m-diisopropylbenzene, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,3-bis (4-hydroxyphenyl) -5, 7-dimethyl adamantane etc. are mentioned. Especially, bisphenol A is preferable at the point that the improvement effect is large. These may be used independently and may be used together 2 or more types. Moreover, a small amount of trifunctional compounds may be used as a branching agent, and a small amount of aliphatic difunctional compounds may be copolymerized.

As the aqueous alkali solution used in the present invention, for example, an aqueous solution of an alkali metal such as sodium hydroxide or potassium hydroxide is preferably used. In particular, an aqueous solution of sodium hydroxide is preferably used.

1.7-4.0 mol is preferable with respect to 1 mol of dihydric phenol compounds, and, as for the amount of alkali used for aqueous alkali solution, 1.9-3.0 mol is more preferable. Moreover, 5.5-8.5 weight% is preferable for the alkali concentration in aqueous alkali solution. When the amount of alkali is less than 1.7 mol with respect to the divalent phenol compound, the progress of the phosgenation reaction and the polymerization reaction is very poor, and the variation in the viscosity average molecular weight of the polycarbonate resin is not preferable. When alkali amount exceeds 4.0 mol with respect to a dihydric phenol compound, since decomposition reaction of phosgene increases, it is unpreferable. Moreover, when the alkali concentration in aqueous alkali solution is less than 5.5 weight%, reaction rate becomes slow and an apparatus also enlarges, and it is unpreferable.

100-190 g / L is preferable and, as for the bivalent phenol compound concentration in aqueous alkali solution, 150-180 g / L is more preferable. When the dihydric phenol compound concentration is less than 100 g / l, the reaction rate is slow and the apparatus is also enlarged, which is not preferable. When the dihydric phenol compound concentration is more than 190 g / l, the dissolution rate of the dihydric phenol compound is lowered, which is not preferable. not. Moreover, as for the alkali aqueous solution temperature of a dihydric phenol compound, 0-40 degreeC is preferable. If the temperature of the aqueous alkali solution is less than 0 ° C., the dihydric phenol compound is precipitated, which may cause operating trouble. If the temperature of the aqueous alkali solution exceeds 40 ° C., the decomposition reaction of phosgene proceeds during the phosgenation reaction. not.

The ratio of the aqueous alkali solution (ii) of the dihydric phenol compound to react with the organic solvent (i) is preferably in the range of 1.0: 0.5 to 1.5 (capacity ratio). Moreover, the range of 1.0: 1.0-1.5 (molar ratio) of the ratio of the aqueous alkali solution (ii) of the dihydric phenol compound made to react and phosgene gas (i) is preferable. As for the temperature of the fluid at the time of mixing said (i)-(i), the range below 0 degreeC or more and the boiling point of a solvent is preferable.

Further, for promoting the reaction, for example, a catalyst such as a tertiary amine or quaternary ammonium salt can be used.

In the present invention, it is preferable to supply the organic solvent (iii), the aqueous alkali solution (ii) and (iv) phosgene gas of the dihydric phenol compound to the mixing reactor continuously or separately as a mixture of any combination.

The mixing reactor is preferably a stationary mixer, ie a static mixer. Static mixers are mixers that do not have moving parts. The mixing reactor is preferably tubular.

The static mixer has an element therein that has the effect of dividing, diverting and inverting the fluid. The element generally has a shape that twists a rectangular plate 180 degrees. The fluid is divided (divided) every time it passes through one element. The fluid is also lined up (transition) from the tube center to the wall and from the tube wall to the center along the torsional surface in the element. In addition, the fluid changes the rotation direction for each element, and undergoes turbulent stirring under inversion of rapid inertia (inversion).

In the static mixer, bubbles in the liquid are refined to increase the contact interface. As a result, the reaction efficiency is dramatically increased.

As a static mixer, SM Park (made by Noritake Co., Ltd.), a high mixer (made by Toray Corporation), etc. are mentioned. The mixing reactor may also be a powered line mixer with moving parts. These mixing reactors may be used independently or may be used together 2 or more types. In the installation of the mixing reactor, it may be provided horizontally, upright or inclined. The reaction temperature in the mixing reactor is preferably in the range of 0 ° C or more and the boiling point of the solvent.

Reynolds number Re of the fluid at the time of reaction becomes like this. Preferably it is 800 or more (turbulent zone), More preferably, it is 5,000-800,000, More preferably, it is 10,000-60,000. When using a stationary mixer especially, Reynolds number becomes like this. Preferably it is 3,000-200,000, More preferably, it is 5,000-150,000. If the Reynolds number is less than 800, the reaction rate is slowed because of poor mixing. If the Reynolds number exceeds 800,000, the pressure loss is large and power is generated dynamically.

Re is computed by the following formula. It calculates based on the capacity, density, and viscosity of the fluid supplied to a mixing reactor.

Re = Duρ / μ

D: inner diameter of the mixing reactor (m)

u: mean flow velocity of fluid (m / s)

β: density of fluid (㎏ / ㎥)

μ: viscosity of the fluid (㎩ · s)

The initial product generated by the reaction is a liquid phase composed of an organic solvent solution of a polycarbonate oligomer and an aqueous alkaline solution containing a small amount of unreacted dihydric phenol, and a gas-liquid mixture of a gaseous phase composed of a trace amount of impurity gas contained in carbon monoxide and carbon monoxide. . It is preferable to make this gas-liquid mixture initial product into the temperature of 30-40 degreeC. The temperature of the initial product is preferably controlled by the amount of recycled cooled product solution to the mixing reactor.

Process (3), (4)

The initial product of the gas-liquid mixture formed by the reaction is introduced into the mixing tank. The mixing tank has a function of cooling the initial product and a function of gas-liquid separation. The mixing tank also has a function of storing the resulting solution obtained by cooling and gas-liquid separation. It is preferable to equip the mixing tank with a stirrer. It is preferable to keep the temperature of the product solution in a mixing tank at 2-25 degreeC.

It is preferable to cool the product solution in a mixing tank via an external heat exchanger using a circulation pump. The circulation flow rate of the product solution is not a problem as long as it is a flow rate that can control the liquid temperature in the mixing tank in a range of preferably 2 to 25 ° C. The circulation flow rate is determined by the capacity of the cooler and the amount of raw material feed, ie the production of polycarbonate oligomers. If the liquid temperature is too low, the solution freezes, making operation difficult. If the liquid temperature is too high, the evaporation of the solvent is increased or the decomposition reaction is accelerated, so that a stable quality is not obtained. That is, it is preferable to collect the generated solution in a mixing tank and cool it while circulating through an external heat exchanger.

The mixing tank may have a cooling function such as a jacket type or an internal coil type. 0.5-60 minutes are preferable, as for the residence time of the production solution in a mixing tank, 1-30 minutes are more preferable, and 1.5-20 minutes are more preferable. If the residence time is too short, the first-class solution from the first-class sphere becomes uneven, and if it is too long, decomposition reactions are likely to occur, and stable quality is difficult to be obtained, and the apparatus is maximized.

Process (3) is a process of cooling an initial product at 2-25 degreeC. It is preferable to cool the initial product which temperature rose by the heat of reaction as quickly as possible, and to suppress the side reaction of phosgene. After the reaction, the initial product is preferably introduced into the mixing bath and cooled. When introducing an initial product from a mixing reactor into a mixing tank, although it may introduce into a liquid or may be introduce | transduced in a gaseous phase, introduction into a liquid is preferable at the point that the dispersion | variation in the quality of the oligomer and polymer obtained is slightly small.

That is, it is preferable to perform cooling of an initial product by making it contact with the product solution obtained by cooling and gas-liquid separation.

Step (4) is a step of gas-liquid separation of the initial product to obtain a product solution. The initial product of the gas-liquid mixed phase generated by the reaction is gas-liquid separated by introduction into the mixing tank. The separated gaseous phase is discharged from the vent port (waste gas discharge pipe) of the mixing tank. That is, it is preferable to introduce | transduce the initial product into the mixing tank in which the product solution obtained by cooling and gas-liquid separation was already stored, and performing gas-liquid separation.

The resulting solution is a liquid phase composed of an organic solvent solution of a polycarbonate oligomer and an alkali aqueous solution containing a small amount of unreacted divalent phenol.

It is preferable to convey the cooled product solution to the upstream, downstream, or both of these mixing reactors. By employ | adopting this method, the dispersion | variation in the quality of the oligomer and polymer obtained when adjusting and changing a production amount becomes small. It is more preferable to convey to the upstream side of a mixing reactor, and it is especially preferable to convey to an upstream side from a raw material supply point. In addition, the conveyance amount of the reaction solution is not particularly limited, but a flow rate at which the Reynolds number Re of the reaction mixture in the reaction mixer can be maintained within the above range is more preferable. That is, it is preferable to add a part of production solution to (iv) organic solvent, (ii) alkali aqueous solution of a bivalent phenol compound, and (iv) phosgene gas provided for reaction.

The viscosity average molecular weight of the polycarbonate oligomer produced by this invention becomes like this. Preferably it is 500-8,000, More preferably, it is 800-5,000.

(Polycarbonate resin)

The organic solvent solution of the polycarbonate oligomer obtained by this invention can superpose | polymerize in presence of aqueous alkali solution, and can manufacture polycarbonate resin. Moreover, in order to accelerate | stimulate a polymerization reaction, you may use catalysts, such as a tertiary amine and a quaternary ammonium salt, for example. As the molecular weight modifier, for example, known terminal terminators such as alkyl substituted phenols such as phenol and p-tert-butylphenol can be used. Reaction temperature is 0-40 degreeC normally, and reaction time is several minutes-5 hours.

That is, according to this invention, the method of manufacturing the polycarbonate resin of the viscosity average molecular weights 10,000-50,000 is further provided by superposing | polymerizing the polycarbonate oligomer in the obtained product solution.

The molecular weight of the polycarbonate resin obtained is preferably 10,000 to 50,000, more preferably 15,000 to 35,000 as the viscosity average molecular weight (M). The polycarbonate resin which has such a viscosity average molecular weight is preferable because sufficient strength is obtained and also melt fluidity at the time of shaping | molding is favorable. The viscosity average molecular weight as used in this invention is calculated | required by inserting the specific viscosity ((eta) _sp ) calculated | required from the solution which melt | dissolved 0.7 g of polycarbonate resins at 20 degreeC in 100 ml of methylene chlorides by following Formula.

η _sp / c = [η] + 0.45 × [η] ² c (where [η] is the ultimate viscosity)

[η] = 1.23 × 10 ^-4 M ^{0 .83}

c = 0.7

Next, the flow sheet which shows one aspect of the method of this invention is shown to FIG. 1 and FIG.

1 is a flow sheet showing an example of a step of producing a phosgene gas. It is a flow sheet which shows an example of the manufacturing process of a polycarbonate oligomer.

In Fig. 1, a is a carbon monoxide supply pipe, b is a chlorine supply pipe, c is a mixer, d is a reaction tower, e is a gas flow meter, f is a gas extraction tube, g is a gas through pipe, h is a cooler, and i is a liquid. A phosgene reservoir, j is a metering pump, k is a vaporizer, l is a phosgene gas extraction tube, and m is a gas extraction tube.

In Fig. 2, 1, 2 or 3 are each optionally an alkaline aqueous solution supply pipe, an organic solvent supply pipe or a phosgene supply pipe of a dihydric phenol compound, 4 is a mixing reactor, 5 is a mixing tank, 6 is a circulation pump, and 7 is Cooler, 8-1 and 8-2 are circulating pipes, 9-1, 9-2, 9-3, 9-4 and 9-5 are reaction liquid return pipes, 10 is waste gas discharge pipe, 11 is product solution outlet to be.

The present invention will be further described below by way of examples. In addition, the part in an Example is a weight part. Each physical property was measured by the following method.

(1) Measurement of carbon monoxide (CO) concentration (volume%) in phosgene gas

100 ml of gas was absorbed into a phosgene absorbent (25 wt% NaOH aqueous solution), and the volume of residual gas: A (ml) was measured. The solution was combined with 2,280 g of pure water and 50 g of copper), and the volume of residual gas: B (ml) was measured, and the carbon monoxide concentration was inserted into the following equation.

Carbon monoxide concentration (% by volume) = A-B

(2) Determination of Bisphenol A (BPA) Concentration in the Water Phase of the Production Solution

After diluting 100 ml of the resulting solution with 500 ml of methylene chloride, 10 ml of the aqueous phase obtained by standing separation was separated and the absorption peak of bisphenol A was measured at an absorption wavelength of 294 nm using an ultraviolet spectrophotometer (UV system). . As an analytical curve, the analytical curve of the NaOH aqueous-solution concentration of bisphenol A was created at the absorption wavelength of 294 nm using the ultraviolet spectrophotometer (UV system).

(3) Measurement of NaOH, Na ₂ CO ₃ concentration in the water phase

After diluting 100 ml of the resulting solution with 500 ml of methylene chloride, 10 ml of the aqueous phase obtained by standing separation was collected and neutralized and measured with a 1 N aqueous hydrochloric acid solution.

(4) Measurement of viscosity average molecular weight of polycarbonate oligomer

The polycarbonate oligomer organic solvent solution was washed in ion-exchanged water until the conductivity of the aqueous phase was about the same as the ion-exchanged water, and then the polycarbonate oligomer organic solvent solution was separated and collected, and the organic solvent was evaporated off. It dried for 5 hours, and measured the viscosity average molecular weight. The measurement of the viscosity average molecular weight was calculated | required by inserting the specific viscosity ((eta) _sp ) calculated | required from the solution which melt | dissolved 0.7 g of polycarbonate oligomers at 100 degreeC in 100 ml of methylene chlorides in the following formula.

η _sp / c = [η] + 0.45 × [η] ² c (where [η] is the ultimate viscosity)

[η] = 1.23 × 10 ^-4 M ^{0 .83}

c = 0.7

(5) Measurement of viscosity average molecular weight of polycarbonate resin

The specific viscosity (η _sp ) obtained from the solution in which 0.7 g of polycarbonate resin was dissolved in 100 ml of methylene chloride at 20 ° C. was obtained by inserting the following equation.

η _sp / c = [η] + 0.45 × [η] ² c (where [η] is the ultimate viscosity)

[η] = 1.23 × 10 ^-4 M ^{0 .83}

c = 0.7

(6) Measurement of YI value

Using a polycarbonate resin pellet injection molding machine (manufactured by Nippon Steel Mill Co., Ltd .: Nikko Anka V-17-65 type), a plate for measuring the YI value at a cylinder temperature of 340 degrees for 1 minute cycle (70 mm x 50 mm x 2 Mm) The plate was formed and the flat plate was calculated from X, Y, and Z measured using a colorimeter (Nippon Denshoku Co., Ltd. product: Z-1001DP type) using the following formula based on ASTM-E1925. It was.

YI = [100 (1.28X-1.06Z)] / Y

(7) measurement of b value

The b value of the pellet was measured according to JIS K-7105 using Nippon Denshoku Co., Ltd. model SE-2000.

Example 1

(Production of Fosgen)

The phosgene production flow shown in FIG. 1 was used. The reaction tower (d) is a shell tube type reaction tower. The tube side was filled with 50 kg of coconut shell activated carbon having a packing density of 0.430 g / ml, a specific surface area of 1,300 m 2 / g, a pore volume of 0.98 ml / g, a particle density of 0.69 g / ml, and an average pore diameter of 17.0 nm. Cold water at 20 ° C. was passed through the shell to remove heat of reaction.

The mixer (c) was formed upstream of the reaction tower (d). The raw material is supplied to the mixer (c) by the carbon monoxide supply pipe (a) and the chlorine supply pipe (b).

Downstream of the reaction column (d), a gas flow meter (e), a gas extraction pipe (f), a cooler (h) through which brine at -25 ° C is passed through, a liquefied phosgene storage tank (i), a metering pump (j), and a liquefied phosgene The vaporizer | carburetor (k) and phosgene gas extraction pipe (l) for vaporizing were basically connected in series.

A CO gas 5.73N㎥ / Hr with a purity of 98.5 vol%, a molar ratio of CO / Cl ₂ from, the pipe (a) to be 1.045, the Cl ₂ gas 5.40N㎥ / Hr of feed, and the gas from the pipe (b) It mixed in the stationary mixer (c), and made it react by venting to the reaction tower (d). The phosgene gas was used by extracting a gas having a temperature of 30 ° C discharged from the reaction tower (d) from the gas extraction pipe (f).

(reaction)

It implemented using the manufacturing flow shown in FIG.

As the mixing reactor 4, a stationary tubular reactor (Static mixer 1-N10-331 type manufactured by Noritake Co., Ltd., element number 6) was used. The raw material is supplied to the mixing reactor 4 by the raw material supply pipes 1 to 3.

On the downstream side of the mixing reactor 4, a mixing tank 5 having an effective capacity of 50 liters having a first-class opening 11 was formed. The mixing tank 5 provided the circulation pump 6 which circulates and conveys the product solution, and the multi-pipe heat exchanger 7 which circulate-cools the reaction solution. The initial product from the mixing reactor 4 was introduced into the liquid of the mixing tank 5.

50 parts by weight of 2,2-bis (4-hydroxyphenyl) propane (bisphenol A), 18.2 parts by weight of sodium hydroxide, 251.0 parts by weight of water and 0.1 parts by weight of hydrosulfite were mixed at a temperature of 20 ° C. (170 g / l ) 294 L / hr was supplied from the piping 1 to the mixing tank 5 via the mixing reactor 4.

110 m / hr of methylene chloride was supplied from the pipe 2 to the mixing tank 5 via the mixing reactor 4.

When the mixed solution of bisphenol A solution and methylene chloride began to flow from the first-class port 11 of the mixing tank 5, the mixed solution of bisphenol A solution and methylene chloride in the mixing tank 5 was lowered in the mixing tank 5 A part was extracted from the liquid, and the liquid feeding to the cooler 7 was started with the circulation pump 6. A part of the cooled solution was returned from the pipe 9-1 at 500 L / hr, and the remaining solution 12,000 L / hr was returned from the pipe 8-1 to the mixing tank 5.

When the liquid temperature in the mixing tank 5 was controlled at 20 ° C, the phosgene gas (puregen content 23.9 kg / hr) having a carbon monoxide concentration of 5.76% by volume extracted from the gas extraction tube (f) and a temperature of 30 ° C was piped (3) Starting to feed from. At this time, the Reynolds number of the fluid in the mixing reactor 4 was about 36,000 (the fluid density (ρ) was calculated as 1,140 kg / m 3 and the viscosity (μ) was 0.001 Pa · s).

The resulting solution was continuously extracted from the first outlet 11 of the mixing tank, and 30 minutes after the start of the phosgene gas supply, the outlet temperature of the mixing reactor 4 was stabilized at 35.3 ± 0.2 ° C., so it was produced from the first outlet 11 of the mixing tank. The solution was collected separately. The residence time of the product solution in the mixing tank 5 was about 15 minutes. Table 1 shows the molecular weight of the polycarbonate oligomer in the resulting solution and various evaluation results of the resulting solution.

(Production of Polycarbonate Resin)

Next, 18.2 kg / hr of a methylene chloride solution of 5.9 L / hr of 48.5% by weight aqueous sodium hydroxide solution and 10% by weight of p-tert-butylphenol was obtained from the first outlet 11 of the mixing tank 5. The homo mixer was fed continuously and mixed emulsified. This emulsion was fed from the lower part of the polymerization tower with a stirrer (residence time 1.5 hours) which has a 1st-sphere, and superposed | polymerized reaction. The polymerization product liquid was continuously extracted from the upper first-class sphere, and 150 l / hr of methylene chloride was added to the polymerization product liquid, followed by dilution. The organic solvent solution phase and the water phase were separated by a centrifuge, and the polycarbonate resin concentration was 14.5% by weight. An organic solvent solution was obtained. After adding and stirring 200 L of ion-exchange water to 300 L of this organic solvent solutions, stirring was stopped and the water phase and the organic phase were isolate | separated. This operation was repeated until the electrical conductivity of the aqueous phase was approximately equal to that of ion exchanged water (4 times). The obtained purified polycarbonate resin solution was filtered with the filtration precision 1 micrometer filter made from SUS304.

(Manufacture of pellets)

Next, 100L of ion-exchanged water was put into a 1000L kneader made of SUS316L, and the inner wall of the inner wall where the isolation chamber having the foreign matter outlet was formed was put in the bearing part, and methylene chloride was evaporated by dropping the organic solvent solution at a water temperature of 42 ° C. It was. The mixture of powder and water was put into the hot water treatment tank with a stirrer controlled by the water temperature of 95 degreeC, and it stirred and mixed for 30 minutes by the mixing ratio of 25 parts of powder and 75 parts of water. Subsequently, the mixture of powder and water was separated by centrifugal separator, and the powder containing 0.5 weight% of methylene chloride and 45 weight% of water was obtained.

Next, this powder is continuously supplied to a conductive hydrothermal spherical biaxial stirring continuous dryer made of SUS316L controlled at 140 ° C. at 50 kg / hr (polycarbonate resin equivalent), and dried under conditions of an average drying time of 6 hours. Then, the granule of viscosity average molecular weight 15000 and methylene chloride content 50 ppm was obtained. 300 ppm of the following phosphorus stabilizer (a) and 0.06 weight% of stearic acid monoglycerides were added to this powder, and it mixed. Next, the granules are melt-kneaded while degassing with a vent type twin screw extruder (KTX-46 manufactured by Kobe Steel Co., Ltd.) at a cylinder temperature of 260 ° C. and vent gas suction degree of -667 kPa to obtain pellets. Is shown in Table 1.

Phosphorus-based heat stabilizer (a): A mixture of 71: 15: 14 (weight ratio) of the following a-1 component, a-2 component and a-3 component

a-1 component: tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,4-di-t-butylphenyl) -4,3 100: 50: 10 (by weight) mixture of '-biphenylenediphosphonite and tetrakis (2,4-di-t-butylphenyl) -3,3'-biphenylenediphosphonite

a-2 component: bis (2,4-di-tert-butylphenyl) -4-phenyl-phenylphosphonite and bis (2,4-di-tert-butylphenyl) -3-phenyl-phenylphosphonite 5: 3 (weight ratio) mixture

a-3 component: tris (2,4-di-tert-butylphenyl) phosphite

Example 2

It carried out by the method similar to Example 1 except changing conveyance of a part of cooled solution from piping 9-1 to piping 9-3. At this time, the Reynolds number of the fluid in the mixing reactor 4 was about 36,000. Table 1 shows the evaluation results of the obtained oligomer and polymer.

Example 3

It carried out by the method similar to Example 1 except having changed the mixing reactor 4 into the stationary tubular mixer (SM Park of Noritake Co., Ltd.). At this time, the Reynolds number of the fluid in the mixing reactor 4 was about 24,000. Table 1 shows the evaluation results of the obtained oligomer and polymer.

Example 4

It carried out by the method similar to Example 1 except changing the flow volume of the methylene chloride solution of 10 weight% of p-tert- butylphenol to 9.85 kg / hr. Table 1 shows the evaluation results of the obtained oligomer and polymer.

Example 5

It carried out by the method similar to Example 1 except having made double-input amount, flow volume, and conveyance quantity of all the materials in Example 1. At this time, the Reynolds number of the fluid in the mixing reactor 4 was about 72,000. Table 1 shows the evaluation results of the obtained oligomer and polymer.

Comparative Example 1

A polycarbonate oligomer was prepared in the same manner as in Example 1 except that the liquid temperature in the mixing tank 5 was controlled at 35 ° C., and as shown in Table 1, Na ₂ generated by decomposition of unreacted bisphenol A and phosgene. CO ₃ becomes very large, the productivity was lowered.

Effects of the Invention

According to this invention, it can be used for manufacture of a polycarbonate oligomer as it is, without cooling the phosgene gas obtained by making carbon monoxide and chlorine react.

Moreover, according to this invention, a polycarbonate oligomer can be manufactured continuously with favorable productivity at low cost with a simple installation. Specifically, according to the present invention, gas-liquid separation after the reaction can be easily performed. Moreover, the side reaction of phosgene gas can be suppressed and a polycarbonate oligomer can be manufactured efficiently. In addition, the initial product can be cooled rapidly, the side reaction of phosgene gas can be suppressed, and the polycarbonate oligomer can be efficiently produced. In addition, by circulating the product solution to the upstream side of the reactor, control of the reaction temperature and adjustment of the production amount can be easily performed.

Moreover, according to this invention, the polycarbonate oligomer and polycarbonate resin of the outstanding quality can be manufactured.

According to the present invention, since the polycarbonate oligomer can be produced at a low cost and with good productivity with a simple facility, it can be applied to the production process of the polycarbonate resin.

Claims (14)

As a method for continuously producing a polycarbonate oligomer by reacting an aqueous alkali solution (ii) of a dihydric phenol compound and a phosgene gas (iii) in the presence of an organic solvent (iii), (1) a step of reacting chlorine and carbon monoxide at a ratio of 1.01 to 1.3 mol of carbon monoxide with respect to 1 mol of chlorine to obtain a phosgene gas containing 1 to 30% by volume of carbon monoxide; (2) a step of continuously reacting an organic solvent (iii), an aqueous alkali solution (ii) of the dihydric phenol compound and the obtained phosgene gas (iii) to obtain a gas-liquid mixed initial product, (3) cooling the initial product to 2 to 25 ° C, and (4) A process comprising gas-liquid separation of the initial product to obtain a product solution containing a polycarbonate oligomer. The method of claim 1, The bivalent phenolic compound is bisphenol A. The method of claim 1, The aqueous alkali solution is an aqueous solution of sodium hydroxide. The method of claim 1, The organic solvent (i) is methylene chloride. The method of claim 1, The step (1) of obtaining phosgene gas is a step of reacting chlorine and carbon monoxide at a ratio of 1.02 to 1.2 moles of carbon monoxide with respect to 1 mole of chlorine to obtain a phosgene gas containing 2 to 20% by volume of carbon monoxide. The method of claim 1, Process (2) of obtaining an initial product in a stationary mixer. The method of claim 1, The Reynolds number of the fluid in the reaction is 10,000 to 600,000. The method of claim 1, The temperature of the initial product is 30-40 ° C. The method of claim 1, The cooling of the initial product is carried out by contacting with a product solution obtained by cooling and gas-liquid separation. The method of claim 1, A method in which an initial product is introduced into a mixed tank in which a product solution obtained by cooling and gas-liquid separation is already stored, and then gas-liquid separation. The method of claim 1, The resulting solution is collected in a mixing tank and cooled while circulating through an external heat exchanger. The method of claim 1, A method of adding a part of the resulting solution to an organic solvent (i) to be provided for the reaction, an aqueous alkali solution (ii) of a dihydric phenol compound and a phosgene gas (iii). The method of claim 1, The method whose viscosity average molecular weight of a polycarbonate oligomer is 500-8,000. A method for producing a polycarbonate resin having a viscosity average molecular weight of 10,000 to 50,000 by further polymerizing a polycarbonate oligomer in a product solution obtained by the method according to claim 1.

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