JP2007119691A - Polycarbonate oligomer and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a homogeneous polycarbonate oligomer having high terminal chloroformate group concentration and low terminal nitrogen content. <P>SOLUTION: The polycarbonate oligomer contains a structural unit expressed by general formula (1) (X and X' are each hydrogen atom, a halogen atom or methyl group; and R is hydrogen atom, a halogen atom, hydroxyl group, carbonyl group, acetyl group or a 1-20C alkyl group), wherein ≥95% of the oligomer terminal is derived from a chloroformate group, a terminal nitrogen content is ≤5 ppm and a number-average molecular weight is 1,000-5,000. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polycarbonate oligomer and a method for producing the same.

Conventionally, a polycarbonate oligomer is produced by reacting an alkaline aqueous solution of an aromatic diol with phosgene in the presence of an inert organic solvent to produce a polycarbonate oligomer (hereinafter referred to as “oligomer”), and separating the aqueous phase from the reaction mixture. A method is known in which an organic solvent phase (hereinafter referred to as “oil phase”) containing an oligomer is removed to obtain a high molecular weight polycarbonate by adding a polymerization catalyst and an alkaline aqueous solution to perform polymerization.
For example, Patent Document 1 discloses a phosgenation reaction of 10 ° C. or less, Patent Document 2 includes 2 ° C. to 30 ° C., Patent Document 3 includes a first reactor of 10 ° C. to 25 ° C., and a second reactor of 10 ° C. to 30 ° C. A method of reacting at a low temperature has been proposed.
In Patent Document 4, an oligomerization reaction is performed until the gram equivalent ratio of the alkali metal atom to the hydroxyl group of the aromatic diol is 0.9 to 1.5 and reacted with phosgene until the pH after the reaction is 5 to 10. A way to do it has been proposed.
Furthermore, Patent Document 5 proposes to increase the molecular weight by using a water-soluble and oil-soluble polymerization catalyst in combination.

JP-A-55-052321 JP 58-108226 A Japanese Patent Laid-Open No. 62-167321 Japanese Patent Laid-Open No. 03-109420 JP 61-238823 A

However, in the conventional reports, most of the aromatic diols are mainly related to the oligomer production method using 2,2-bis (4-hydroxyphenyl) propane (= bisphenol A), and other aromatic diols. There are few specific examples of oligomers using diols and methods for producing the same.
One reason for this is that even if the types of aromatic diols are different, it is assumed that oligomers of substantially the same quality can be produced under the same conditions. However, depending on the aromatic diol used, the solubility of the aromatic diol is completely different from the others even in the stage of preparing an alkaline aqueous solution of the aromatic diol, and the target oligomer is different from the difference in reactivity with phosgene. As a result, it is often impossible to obtain a high-quality product, for example, the high molecular weight in the polymerization reaction is incomplete or the detergency in the polymer washing step is deteriorated.

For example, in the method of reacting at a low temperature as described in Patent Document 1 to Patent Document 3, when an aqueous alkali solution of a specific aromatic diol is pre-cooled, the solubility is lowered and the aromatic diol is precipitated and a uniform reaction can be achieved. In practice, it may be difficult to obtain an oligomer.
Further, in the method as described in Patent Document 4, an intermediate phase is generated at the interface between the oil phase and the aqueous phase after the oligomerization reaction is completed, so that it is difficult to separate the aqueous phase. Therefore, there is a problem that the product quality is inferior without high molecular weight.
Furthermore, in the method as described in Patent Document 5, although high molecular weight can be achieved, the dissolution of aromatic diol (BPZ) under the temperature condition (20 ° C.) described in the examples is practically practical. Have difficulty. Moreover, not only does it take a great deal of effort to separate and recover the catalyst used, but the polymerization reaction is carried out without separating the oligomer and the aqueous phase, so the total reaction volume is more than doubled compared to the case where the aqueous phase is not separated. There is a problem that an increase in size is inevitable.

The present invention has been made to solve such problems.
That is, an object of the present invention is to provide a uniform polycarbonate oligomer having a high chloroformate group terminal and a low terminal nitrogen content.
Another object of the present invention is to provide a method for producing a polycarbonate oligomer using an aromatic diol having a specific structure.

  In order to solve the above-mentioned problems, as a result of intensive research, the present inventors have obtained an oligomer having excellent quality using an aromatic diol having the following structure:

The reaction mixture after completion of the reaction is prepared by adjusting the alkaline aqueous solution of the aromatic diol under specific conditions and then reacting with phosgene and performing oligomerization reaction in the absence of a catalyst until the pH after completion of the reaction is 10 to 12. As a result, the present inventors have found that it is easy to separate the aqueous phase from the mixture, and that a high-quality and uniform oligomer can be obtained with good reproducibility.

  That is, according to the present invention, firstly, in claim 1, a polycarbonate oligomer having a number average molecular weight of 1000 to 5000 containing a structural unit represented by the following general formula (1), % Or more is a group derived from a chloroformate group, and the amount of nitrogen bonded to the molecular end is 5 ppm or less.

(In general formula (1), X and X ′ represent a hydrogen atom, a halogen atom or a methyl group, and R represents a hydrogen atom, a halogen atom, a hydroxyl group, a carbonyl group, an acetyl group, or an alkyl group having 1 to 20 carbon atoms. Is shown.)

Second, in claim 2, an alkaline aqueous solution of an aromatic diol represented by the following general formula (2) is reacted with phosgene in the presence of an inert organic solvent, and the aqueous phase is separated and removed from the resulting reaction mixture. In a method for producing a polycarbonate oligomer,
(A) The gram equivalent ratio of the alkali metal atom to the hydroxide of the aromatic diol in the alkali aqueous solution having an alkali metal hydroxide concentration of 3.0% to 6.0% by weight is 1.5 to 2.0%. An alkaline aqueous solution of an aromatic diol adjusted to be in a temperature range of 40 ° C. to 50 ° C. while being contacted with phosgene,
(B) The method for producing a polycarbonate oligomer according to claim 1, wherein the oligomerization reaction is carried out in the absence of a catalyst until the pH after completion of the reaction becomes 10-12.

(In general formula (2), X and X ′ represent a hydrogen atom, a halogen atom or a methyl group, and R represents a hydrogen atom, a halogen atom, a hydroxyl group, a carbonyl group, an acetyl group, or an alkyl group having 1 to 20 carbon atoms. Is shown.)

  According to the present invention, it is easy to separate and remove the aqueous phase from the reaction mixture obtained after completion of the oligomerization reaction, and a uniform polycarbonate oligomer having a high terminal chloroformate fraction and a low terminal nitrogen is obtained.

The best mode for carrying out the present invention (hereinafter, an embodiment of the present invention) will be described in detail below. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.
The polycarbonate oligomer to which this embodiment is applied is a polycarbonate oligomer having a number average molecular weight of 1000 to 5000 containing the structural unit represented by the general formula (1) described above, and 95% or more of the oligomer ends are chloro. It is a group derived from a formate group and is characterized in that the amount of nitrogen bound to the molecular end is 5 ppm or less.

  In the present embodiment, the above-described aromatic diol of the general formula (2) is used for the polycarbonate oligomer containing the structural unit represented by the general formula (1). Specific examples of the aromatic diol represented by the general formula (2) include those having the structures shown below.

  However, the compound described above is an exemplification, and does not indicate all the compounds of the general formula (2) in the present embodiment. In the present embodiment, all the compounds satisfying the general formula (2) are included. Applicable.

  In addition, the aromatic diol used in the present embodiment preferably has a high purity, and more preferably 99.5% or more. In particular, the nitrogen content is preferably small in terms of the quality of the polycarbonate, and is required to be 5 ppm or less.

Aromatic diols form an aqueous phase with water and water-soluble metal hydroxides. As the metal hydroxide, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is usually used, and a small amount of a reducing agent such as hydrosulfite may be added.
In the present embodiment, the alkali metal hydroxide concentration of the aqueous alkali solution is set to 3.0 wt% to 6.0 wt%, and the gram equivalent ratio of alkali metal atoms to the hydroxide of the aromatic diol is 1.5 to It is necessary to adjust to be 2.0. Accordingly, the concentration of the aromatic diol in the alkaline aqueous solution is in a range appropriately selected from these relationships. What is important here is that both of the above conditions must be satisfied at the same time, and the effect of the present invention cannot be achieved simply by selecting either of the above conditions.

  For example, even if the alkali metal hydroxide concentration of the alkaline aqueous solution is in the range of 3.0 wt% to 6.0 wt%, the gram equivalent ratio of the alkali metal atom to the hydroxide of the aromatic diol is less than 1.5. As a result, the aromatic diol used in the present embodiment is difficult to dissolve, and even when reacted with phosgene in this state, a uniform oligomer cannot be obtained. On the other hand, if it exceeds 2.0, the dissolution of the aromatic diol becomes easy, but not only the decomposition reaction of phosgene increases rapidly, but also a large amount of alkali remains after completion of the oligomerization reaction, so that the aqueous phase is separated from the reaction mixture. Is not preferable.

  Moreover, even if the gram equivalent ratio of the alkali metal atom to the hydroxide of the aromatic diol is in the range of 1.5 to 2.0, the alkali metal is reacted with phosgene at an alkali metal hydroxide concentration of less than 3.0. And an oligomer having an increased number of hydroxyl ends, which is not preferable because low molecular weight substances increase during the high molecular weight reaction. On the other hand, if it exceeds 6.0% by weight, the decomposition of phosgene increases as described above, and the aqueous phase separation from the reaction mixture becomes more difficult.

  Moreover, in this Embodiment, it is necessary to make the alkaline aqueous solution of the prepared aromatic diol contact with phosgene in the state maintained in the temperature range of 40 to 50 degreeC. When the temperature is lower than 40 ° C., aromatic diol begins to precipitate, the supply pipe is blocked, or the aromatic diol comes into contact with phosgene in a slurry state, which causes a phenomenon that phosgene blows out from the reactor outlet in an unreacted state. . On the other hand, if it exceeds 50 ° C., it is difficult to control the reaction temperature for phosgenation, and the decomposition reaction of phosgene is extremely increased.

  Moreover, in this Embodiment, arbitrary branching agents can also be used as the raw material of polycarbonate. The branching agent used can be selected from a variety of compounds having three or more functional groups. Suitable branching agents include compounds having 3 or more phenolic hydroxyl groups, such as 2,4-bis (4-hydroxyphenylisopropyl) phenol, 2,6-bis (2-hydroxy- 5-methylbenzyl) -4-methylphenol, 2- (4-hydroxyphenyl) -2- (2,4-dihydroxyphenyl) propane and 1,4-bis (4,4′-dihydroxytriphenylmethyl) benzene Can be mentioned. Further, 2,4-dihydroxybenzoic acid, trimesic acid, and cyanuric chloride, which are compounds having three functional groups, can also be used. Of these, those having three or more phenolic hydroxy groups are preferred. The amount of the branching agent used varies depending on the target branching degree, but is usually used in an amount of 0.05 mol% to 2 mol% with respect to the aromatic diols.

  In the present embodiment, monophenols used as molecular weight regulators include various phenols, for example, normal phenol, carbon number 1 to carbon number such as pt-butylphenol and p-cresol. 20 alkylphenols and halogenated phenols such as p-chlorophenol and 2,4,6-tribromophenol are included. Of these, phenols and phenols substituted with an alkyl group having 1 to 20 carbon atoms in the para position such as p-isopropylphenol, p-dodecylphenol, and pt-butylphenol are more preferable. The amount of monophenols used varies depending on the molecular weight of the intended condensate, but is usually 0.5 to 10% by weight based on the starting aromatic diol.

  As the organic solvent to be used, any inert organic substance that dissolves reaction products such as phosgene and carbonate oligomers and polycarbonate but does not dissolve water (in the sense that it does not form a solution with water) at the reaction temperature and pressure. Contains solvent.

  Typical inert organic solvents include aliphatic hydrocarbons such as hexane and n-heptane; such as methylene chloride, chloroform, carbon tetrachloride, dichloroethane, trichloroethane, tetrachloroethane, dichloropropane and 1,2-dichloroethylene. Chlorinated aliphatic hydrocarbons; Aromatic hydrocarbons such as benzene, toluene and xylene; Chlorinated aromatic hydrocarbons such as chlorobenzene, o-dichlorobenzene and chlorotoluene; Other substituted aromatic carbons such as nitrobenzene and acetophenone Hydrogen is included.

  Of these, chlorinated hydrocarbons such as methylene chloride or chlorobenzene are preferably used. These inert organic solvents can be used alone or as a mixture with other solvents.

  Phosgene is used in liquid or gaseous form. From the viewpoint of temperature control, phosgene is preferably in a liquid state, and a reaction pressure that can maintain the liquid state at the reaction temperature is selected. The preferred amount of phosgene is affected by the reaction conditions, particularly the reaction temperature and the concentration of the aromatic diol metal salt in the aqueous phase, but is usually the number of moles of phosgene per mole of aromatic diols, usually 1 to 2, preferably 1 to 1.5. If this ratio is too large, the loss of phosgene increases, and the formation of a condensate between terminators is observed, which is not preferable. On the other hand, if it is too small, the CO group is insufficient, and proper molecular weight elongation cannot be performed, which is not preferable.

  In the present embodiment, when the two-phase interfacial condensation method is adopted, it is particularly preferable that the organic phase and the aqueous phase are brought into contact with each other prior to contact with phosgene to form an emulsion. In order to form an emulsion, in addition to a stirrer having a normal stirring blade, a dynamic mixer such as a homogenizer, a homomixer, a colloid mill, a flow jet mixer, an ultrasonic emulsifier, or a mixer such as a static mixer Is preferably used. The emulsion usually has a droplet diameter of 0.01 μm to 10 μm and has emulsion stability.

  The state of emulsification can be usually expressed by the Weber number or P / q (additional power value per unit volume). The Weber number is preferably 10,000 or more, more preferably 20,000 or more, and most preferably 35,000 or more. Also, the upper limit is about 1,000,000 or less. P / q is preferably 200 kg · m / liter or more, more preferably 500 kg · m / liter or more, and most preferably 1,000 kg · m / liter or more.

  The contact between the emulsion and phosgene is preferably carried out under mixing conditions weaker than the emulsification conditions in order to suppress dissolution of phosgene in the organic phase, and the Weber number is less than 10,000, preferably 5,000. Less than, more preferably less than 2,000. Further, P / q is less than 200 kg · m / liter, preferably less than 100 kg · m / liter, and more preferably less than 50 kg · m / liter. Contact with phosgene can be achieved by introducing phosgene into a tubular reactor or tank reactor.

  The molecular weight of the polycarbonate is determined by the addition amount of a molecular weight regulator such as monophenol. However, from the viewpoint of molecular weight controllability, the addition timing is preferably from immediately after the consumption of the carbonate-forming compound is completed and before the molecular weight elongation starts. When monophenols are added in the presence of a carbonate-forming compound, a large amount of condensates (diphenyl carbonates) of monophenols are formed, making it difficult to obtain a polycarbonate resin with the target molecular weight, while addition of monophenols When the product is extremely delayed, the control of the molecular weight becomes difficult, and the product has a specific shoulder on the low molecular weight side of the molecular weight distribution, and there are many adverse effects such as dripping at the time of molding.

  The oligomerization reaction must be carried out in the absence of a catalyst. In the presence of a condensation catalyst, for example, when the reaction is carried out by adding commonly used triethylamine, it is easy to separate the aqueous phase from the reaction mixture, but most of the added triethylamine is due to the high alkali concentration in the aqueous phase. Are distributed in the oil phase, and triethylamine reacts with the oligomeric terminal chloroformate to form a thermally unstable urethane linkage, resulting in only oligomers already rich in terminal nitrogen at the oligomer stage. When an oligomer having a large amount of terminal nitrogen is polymerized to obtain a high molecular weight polycarbonate, a product colored with high temperature molding and having a good color tone cannot be obtained. When used as a binder resin for an electrophotographic photoreceptor, abnormal charging is exhibited. When oligomerization is performed using a normal aqueous solution of bisphenol A, the pH after the reaction is almost neutral at 7-8, so that the above problems hardly occur, but the aromatic used in the present invention. Since the alkaline aqueous solution of diol has a high alkali concentration, even if the catalyst is added in this state, the pH after completion of the reaction does not become 7-8.

  It is necessary to carry out the oligomerization reaction in the absence of a catalyst until the pH after completion of the reaction becomes 10-12. If the reaction is carried out in the absence of a catalyst until the pH is less than 10, it is difficult to obtain an oligomer having a high hydroxyl end and a high chloroformate end, and an intermediate phase is likely to be generated at the interface between the aqueous phase and the oil phase from the reaction mixture. Separation may be difficult. On the other hand, pH 12 is not preferable because the reaction mixture emulsifies and the aqueous phase and the oil phase cannot be separated.

  The reaction temperature for obtaining the oligomer is 80 ° C. or lower, preferably 60 ° C. or lower. The reaction time depends on the reaction temperature, but is usually 0.5 minutes to 10 hours, preferably 1 minute to 2 hours. If the reaction temperature is too high, side reactions cannot be controlled, and the phosgene basic unit deteriorates. On the other hand, if it is too low, this is a preferable situation in terms of reaction control, but the refrigeration load increases, and the cost increases accordingly, which is not preferable.

  The oligomer concentration in the organic phase may be within a range in which the resulting oligomer is soluble, and is specifically about 10% by weight to 30% by weight. The ratio of the organic phase is preferably a volume ratio of 0.2 to 1.0 with respect to the aqueous solution of an alkali metal hydroxide of an aromatic diol, that is, the aqueous phase.

  When the oligomerization reaction is performed under such conditions, separation of the organic phase in which the oligomer is dissolved after the completion of the reaction and the aqueous phase is facilitated, and the number average molecular weight of the obtained carbonate oligomer is 1000 to 5000, Since 95% or more is a group derived from a chloroformate group and the amount of nitrogen bonded to the molecular end is 5 pmm or less, a uniform high molecular weight polycarbonate can be obtained with good reproducibility by a polycondensation reaction.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. Moreover, each measured value in an Example is calculated | required with the following method.
(1) Oligomer terminal chloroformate group concentration (CF)
After diluting the oligomer solution with methylene chloride, aniline and pure water were added, and titration was carried out with normal NaOH using phenolphthalein as an indicator.
(2) Oligomer end phenolic OH group concentration (OH)
After diluting the oligomer solution with methylene chloride, the solution was colored by adding titanium tetrachloride and acetic acid solution, and the absorbance at a wavelength of 546 nm was measured using a spectrophotometer (UV-160, manufactured by Hitachi, Ltd.). Separately, an extinction coefficient was determined using a methylene chloride solution of an aromatic diol used during the production of the oligomer, and the amount of terminal phenolic OH groups of the oligomer was determined.

(3) Amount of oligomer end terminator (PTBP)
The amount obtained by subtracting the amount of free terminator from the total amount of terminator in the oligomer was taken as the terminator end group amount.
(I) Total terminator amount 1N potassium hydroxide-methanol solution was added to the oligomer solution, alkali hydrolysis was performed at 65 ° C for 1 hour, and the sample was measured according to the following liquid chromatography (LC) conditions and the area correction coefficient obtained in advance. The total amount of terminator was calculated.
Column: Nucleosil ODS 5 μm 4.6 mmφ * 150 mm
Eluent: acetonitrile / water (1/1 v / v)
Detector: UV270nm
(Ii) Amount of free termination agent The oligomer solution was measured under the following liquid chromatography (LC) conditions, and the amount of free termination agent in the sample was calculated from the area correction coefficient determined in advance.
Column: Nucleosil 100A 4.6mmφ * 250mm
Eluent: Liquid A) Normal hexane / tetrahydrofuran (1/1 v / v) Liquid B) Tetrahydrofuran 100%
30 minutes linear gradient detector from A liquid) to B liquid): UV270nm

(4) Oligomer number average molecular weight (Mn)
The number average molecular weight of the oligomer was calculated by the following formula.
Mn = 106 / (total amount of terminal groups (μeq / g) × 1/2)
Total terminal group amount (μeq / g) = CF + OH + PTBP
(5) Chloroformate group fraction The chloroformate group fraction was calculated by the following formula.
Chloroformate group fraction (%) = (terminal chloroformate group concentration / total terminal group amount) × 100
(6) Amount of nitrogen bound to the oligomer end (OG-N)
10 ml of the oligomer solution was shaken and washed with 10 ml of 0.05 N nitric acid aqueous solution for 5 minutes to remove free nitrogen, and then the oligomer solution washed three times with pure water until the pH became neutral was concentrated and dried on a hot plate. The amount of nitrogen bound to the end of the oligomer was measured with a total nitrogen analyzer (TN-10) manufactured by Mitsubishi Chemical Corporation.

[Example 1]
An aqueous solution (Na / OH gram equivalent ratio = 1.5) prepared by dissolving the aromatic diol of the compound (1) described above in a sodium hydroxide aqueous solution having a concentration of 3.37% by weight to 45% by weight was obtained at 45 ° C. The organic phase of 45.5 kg / hour of methylene chloride, adjusted to 119 kg / hour and cooled to 5 ° C., is supplied to a stainless steel pipe having an inner diameter of 6 mm and an outer diameter of 8 mm, mixed in the same pipe, and further a homomixer An emulsion was prepared by emulsification using a special machine chemical (trade name, TK homomic line flow LF-500 type).

  The thus obtained emulsion of an aqueous solution (aqueous phase) and methylene chloride (organic phase) of an aromatic diol sodium salt is taken out from a homomixer through a pipe having an inner diameter of 6 mm and an outer diameter of 8 mm. In a Teflon (registered trademark) pipe reactor having an inner diameter of 6 mm and a length of 34 m connected to the liquefied phosgene, it was brought into contact with 4.4 kg / hour of liquefied phosgene supplied from a pipe cooled to 0 ° C. separately introduced here.

  The emulsion was subjected to phosgenation and oligomerization while flowing through phosgene and a pipe reactor at a linear speed of 1.7 m / sec for 20 seconds. At this time, each reaction temperature was adjusted to 55 ° C., and both were externally cooled to 35 ° C. before entering the next oligomerization tank. Thus, the oligomerized emulsion obtained from the pipe reactor and the 10% by weight methylene chloride solution of pt-butylphenol were introduced into a reaction vessel equipped with a stirrer having an internal volume of 50 liters at a rate of 0.49 kg / hour. By stirring at 30 ° C. in a nitrogen gas atmosphere and oligomerizing, the Na salt of the unreacted aromatic diol present in the aqueous phase was completely consumed, and the pH of the reaction solution was 10.9, overflowing The reaction solution was completely separated into an aqueous phase and an organic phase in a stationary separation tank to obtain an oligomeric methylene chloride solution. Table 1 shows the oligomer property values at this time.

[Example 2]
An aqueous solution (Na / OH gram equivalent ratio = 1.9) prepared by dissolving the aromatic diol of compound (1) in an aqueous solution of sodium hydroxide having a concentration of 5.95% by weight was adjusted to 48 ° C. The organic phase of 61.5 kg / hour of methylene chloride cooled to 119 kg / hour and 5 ° C. is supplied to a stainless steel pipe having an inner diameter of 6 mm and an outer diameter of 8 mm, mixed in the same pipe, and then a homomixer (special machine) Emulsified using a product name KK Homomic Line Flow LF-500, manufactured by Kasei Co., Ltd., to prepare an emulsion.

  The thus obtained emulsion of an aqueous solution (aqueous phase) and methylene chloride (organic phase) of an aromatic diol sodium salt is taken out from a homomixer through a pipe having an inner diameter of 6 mm and an outer diameter of 8 mm. In a pipe reactor made of Teflon (registered trademark) having an inner diameter of 6 mm and a length of 34 m connected to the liquefied phosgene, it was brought into contact with liquefied phosgene 5.9 kg / hour supplied from a pipe cooled to 0 ° C. separately introduced here.

  The emulsion was subjected to phosgenation and oligomerization while flowing through phosgene and a pipe reactor at a linear speed of 1.7 m / sec for 20 seconds. At this time, each reaction temperature was adjusted to 55 ° C., and both were externally cooled to 35 ° C. before entering the next oligomerization tank. Thus, the oligomerized emulsion obtained from the pipe reactor and the 10% by weight methylene chloride solution of pt-butylphenol were introduced into a reaction tank equipped with a stirrer with a capacity of 50 liters at 2.4 kg / hour. When the Na salt of the unreacted aromatic diol present in the aqueous phase is completely consumed by stirring at 30 ° C. in a nitrogen gas atmosphere and oligomerizing, the pH of the reaction solution becomes 11.8 and overflow. The reaction solution was completely separated into an aqueous phase and an organic phase in a stationary separation tank to obtain an oligomeric methylene chloride solution. Table 1 shows the oligomer property values at this time.

[Example 3]
An aqueous solution (Na / OH gram equivalent ratio = 1.7) prepared by dissolving the aromatic diol of the compound (12) in an aqueous solution of sodium hydroxide having a concentration of 4.34% by weight to 7.8% by weight was adjusted to 46 ° C. 119 kg / hr and 50.5 kg / hr of organic phase cooled to 5 ° C. are fed to stainless steel pipes with an inner diameter of 6 mm and an outer diameter of 8 mm, mixed in the pipe, and then a homomixer (special An emulsion was prepared by emulsification using Mecha Chemical Co., Ltd., product name TK homomic line flow LF-500 type).

  The thus obtained emulsion of an aqueous solution (aqueous phase) and methylene chloride (organic phase) of an aromatic diol sodium salt is taken out from a homomixer through a pipe having an inner diameter of 6 mm and an outer diameter of 8 mm. In a Teflon (registered trademark) pipe reactor having an inner diameter of 6 mm and a length of 34 m connected to the liquefied phosgene, it was brought into contact with 4.4 kg / hour of liquefied phosgene supplied from a pipe cooled to 0 ° C. separately introduced here.

  The emulsion was subjected to phosgenation and oligomerization while flowing through phosgene and a pipe reactor at a linear speed of 1.7 m / sec for 20 seconds. At this time, each reaction temperature was adjusted to 55 ° C., and both were externally cooled to 35 ° C. before entering the next oligomerization tank. In this way, the oligomerized emulsion obtained from the pipe reactor and the 10% by weight methylene chloride solution of pt-butylphenol were introduced into a reaction vessel equipped with a stirrer having an internal volume of 50 liters at 1.6 kg / hour. When the Na salt of the unreacted aromatic diol present in the aqueous phase is completely consumed by stirring and oligomerizing at 30 ° C. in a nitrogen gas atmosphere, the pH of the reaction solution becomes 11.6 and overflow. The reaction solution was completely separated into an aqueous phase and an organic phase in a stationary separation tank to obtain an oligomeric methylene chloride solution. Table 1 shows the oligomer property values at this time.

[Example 4]
An aqueous solution (Na / OH gram equivalent ratio = 1.5) prepared by dissolving the aromatic diol of the compound (6) in an aqueous solution of sodium hydroxide having a concentration of 3.14% by weight to be 9.0% by weight was adjusted to 43 ° C. 119 kg / hour and 42.5 kg / hour organic phase of methylene chloride cooled to 5 ° C. are supplied to stainless steel pipes each having an inner diameter of 6 mm and an outer diameter of 8 mm, mixed in the pipe, and further mixed with a homomixer (special machine Emulsified using a product name KK Homomic Line Flow LF-500, manufactured by Kasei Co., Ltd., to prepare an emulsion.

  The thus obtained emulsion of an aqueous solution (aqueous phase) and methylene chloride (organic phase) of an aromatic diol sodium salt is taken out from a homomixer through a pipe having an inner diameter of 6 mm and an outer diameter of 8 mm. In a Teflon (registered trademark) pipe reactor having an inner diameter of 6 mm and a length of 34 m connected to the liquefied phosgene, it was brought into contact with 3.9 kg / hour of liquefied phosgene supplied from a pipe cooled to 0 ° C. separately introduced here.

  The emulsion was subjected to phosgenation and oligomerization while flowing through phosgene and a pipe reactor at a linear speed of 1.7 m / sec for 20 seconds. At this time, each reaction temperature was adjusted to 55 ° C., and both were externally cooled to 35 ° C. before entering the next oligomerization tank. Thus, the oligomerized emulsion obtained from the pipe reactor and the 10% by weight methylene chloride solution of pt-butylphenol were introduced into a reaction vessel equipped with a stirrer having an internal volume of 50 liters at a rate of 0.45 kg / hour. When the Na salt of the unreacted aromatic diol present in the aqueous phase is completely consumed by stirring and oligomerizing at 30 ° C. in a nitrogen gas atmosphere, the pH of the reaction solution becomes 10.5 and overflow. The reaction solution was completely separated into an aqueous phase and an organic phase in a stationary separation tank to obtain an oligomeric methylene chloride solution. Table 1 shows the oligomer property values at this time.

[Comparative Example 1]
An aqueous solution (Na / OH gram equivalent ratio = 1.3) prepared by dissolving the aromatic diol of compound (1) in a sodium hydroxide aqueous solution having a concentration of 2.7% by weight to be 6.5% by weight is precipitated at 53 ° C. or higher. Therefore, the organic phase of methylene chloride adjusted to 55 ° C and cooled to 119kg / h and cooled to 5 ° C was supplied to stainless steel pipes with inner diameter of 6mm and outer diameter of 8mm, respectively, and mixed in the same pipe Furthermore, the mixture was emulsified using a homomixer (manufactured by Tokushu Kika Co., Ltd., product name TK homomic line flow LF-500 type) to prepare an emulsion.

  The thus obtained emulsion of an aqueous solution (aqueous phase) and methylene chloride (organic phase) of an aromatic diol sodium salt is taken out from a homomixer through a pipe having an inner diameter of 6 mm and an outer diameter of 8 mm. In a pipe reactor made of Teflon (registered trademark) having an inner diameter of 6 mm and a length of 34 m connected to the liquefied phosgene, it was brought into contact with 4.0 kg / hour of liquefied phosgene supplied from a pipe cooled to 0 ° C. separately introduced here.

  The emulsion was subjected to phosgenation and oligomerization while flowing through phosgene and a pipe reactor at a linear speed of 1.7 m / sec for 20 seconds. At this time, each reaction temperature was adjusted to 55 ° C., and both were externally cooled to 35 ° C. before entering the next oligomerization tank. Thus, the oligomerized emulsion obtained from the pipe reactor and the 10% by weight methylene chloride solution of pt-butylphenol were introduced into a reaction vessel equipped with a stirrer having an internal volume of 50 liters at a rate of 0.56 kg / hour. By stirring at 30 ° C. in a nitrogen gas atmosphere and oligomerizing, when the Na salt of the unreacted aromatic diol present in the aqueous phase is completely consumed, the pH of the reaction solution becomes 9.2 and overflow. The reaction solution was completely separated into an aqueous phase and an organic phase in a stationary separation tank, but an intermediate phase was observed at the interface. Table 1 shows the oligomer property values at this time.

[Comparative Example 2]
An aqueous solution (Na / OH gram equivalent ratio = 1.5) in which the aromatic diol of compound (1) was dissolved in an aqueous solution of sodium hydroxide having a concentration of 7.0% by weight to 13.5% by weight was adjusted to 45 ° C. and 119 kg. The organic phase of 59.5 kg / h of methylene chloride cooled to 5 ° C./hour is supplied to a stainless steel pipe having an inner diameter of 6 mm and an outer diameter of 8 mm, mixed in the same pipe, and further a homomixer (specialized machine) An emulsion was prepared by emulsification using a product name TK homomic line flow LF-500 type manufactured by Co., Ltd.

  The thus obtained emulsion of an aqueous solution (aqueous phase) and methylene chloride (organic phase) of an aromatic diol sodium salt is taken out from a homomixer through a pipe having an inner diameter of 6 mm and an outer diameter of 8 mm. In a pipe reactor made of Teflon (registered trademark) having an inner diameter of 6 mm and a length of 34 m connected to the liquefied phosgene, it was brought into contact with 8.5 kg / hour of liquefied phosgene supplied from a pipe cooled to 0 ° C. separately introduced here.

  The emulsion was subjected to phosgenation and oligomerization while flowing through phosgene and a pipe reactor at a linear speed of 1.7 m / sec for 20 seconds. At this time, the reaction temperature was adjusted to 55 ° C., respectively, and both were externally cooled to 35 ° C. before entering the next oligomerization tank. Thus, the oligomerized emulsion obtained from the pipe reactor and the 10% by weight methylene chloride solution of pt-butylphenol were led to a reaction vessel equipped with a stirrer with an internal volume of 50 liters at 0.94 kg / hour. By stirring at 30 ° C. in a nitrogen gas atmosphere and oligomerizing, the Na salt of the unreacted aromatic diol present in the aqueous phase was completely consumed. The reaction solution was emulsified and the aqueous phase and the organic phase could not be separated in the stationary separation tank.

[Comparative Example 3]
In the oligomerization of Comparative Example 2, the same operation as in Comparative Example 2 was performed, except that 0.27 kg / hour of a 2% by weight aqueous solution of triethylamine was added as a catalyst. The overflowed reaction solution was completely separated into an aqueous phase and an organic phase in a stationary separation tank, but the oligomer terminal nitrogen was as high as 24.8 ppm. Table 1 shows the oligomer property values at this time.

[Comparative Example 4]
In the oligomerization of Example 4, the same operation as in Comparative Example 2 was performed except that 0.13 kg / hour of a 2% by weight aqueous solution of triethylamine was added as a catalyst. The overflowed reaction solution was completely separated into an aqueous phase and an organic phase in a stationary separation tank, but the oligomer terminal nitrogen was as high as 16.2 ppm. Table 1 shows the oligomer property values at this time.

Claims (2)

A polycarbonate oligomer having a number average molecular weight of 1000 to 5000 containing a structural unit represented by the following general formula (1), wherein 95% or more of the oligomer terminals are groups derived from chloroformate groups, and the molecular terminals A polycarbonate oligomer characterized in that the amount of nitrogen bound to is 5 ppm or less.

(In general formula (1), X and X ′ represent a hydrogen atom, a halogen atom or a methyl group, and R represents a hydrogen atom, a halogen atom, a hydroxyl group, a carbonyl group, an acetyl group, or an alkyl group having 1 to 20 carbon atoms. Is shown.) In a method for producing a polycarbonate oligomer by reacting an alkaline aqueous solution of an aromatic diol represented by the following general formula (2) with phosgene in the presence of an inert organic solvent, and separating and removing the aqueous phase from the resulting reaction mixture,
(A) The gram equivalent ratio of the alkali metal atom to the hydroxide of the aromatic diol in the alkali aqueous solution having an alkali metal hydroxide concentration of 3.0% to 6.0% by weight is 1.5 to 2.0%. An alkaline aqueous solution of an aromatic diol adjusted to be in a temperature range of 40 ° C. to 50 ° C. while being contacted with phosgene,
(B) The method for producing a polycarbonate oligomer according to claim 1, wherein the oligomerization reaction is carried out in the absence of a catalyst until the pH after completion of the reaction becomes 10-12.

(In general formula (2), X and X ′ represent a hydrogen atom, a halogen atom or a methyl group, and R represents a hydrogen atom, a halogen atom, a hydroxyl group, a carbonyl group, an acetyl group, or an alkyl group having 1 to 20 carbon atoms. Is shown.)