JPH03174443A - Production of polycarbonate - Google Patents

Abstract

PURPOSE:To prepare a colorless, transparent, high-mol. wt. polycarbonate substantially free from chlorine ion without using toxic phosgene by reacting a dialkyl carbonate with an arom. dihydroxy compd. in the presence of a specific transesterification catalyst. CONSTITUTION:A dialkyl carbonate is reacted with an arom. dihydroxy compd. in the presence of a transesterification catalyst comprising SbR1R2R3 or Sb2Xm (wherein R1, R2, and R3 are each alkyl, phenyl, alkoxy, or phenoxy; X is O or S; and m is 3 or 5). The dialkyl carbonate pref. releases a low-boilng alkyl group when forming a carbonate bond, and pref. if dimethyl carbonate obtd. from methanol, a cheap raw material. As the arom. dihydroxy compd., a compd. of formula I, II, III, or IV (wherein R1, R2, R3, and R4 are each H, 1-8C linear or branched alkyl, or phenyl; X is halogen; n is 0-4) is pref. A pref. transesterification catalyst is Sb2O3.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to the production of high molecular weight polycarbonate obtained by reacting dialkyl carbonate I and an aromatic dihydroxy compound in the presence of SbR1R2R3 or Sb2Xm as a transesterification catalyst. It is about law.

(Prior Art and Problems to be Solved by the Invention) The high molecular weight polycarbonates of the present invention have a wide range of uses, especially for injection bottom shapes or as glass sheets in place of window panes. It is a general-purpose engineering thermoplastic. Although the interfacial polycondensation method is generally effective for producing polycarbonate, it has drawbacks such as the use of toxic phosgene and the fact that chlorine ions remain in the polycarbonate produced. In order to eliminate these drawbacks, it was proposed in 1983 that polycarbonate could be produced by an interfacial polycondensation reaction between liquid trichloromethyl chloroformate, which is a dimer of phosgene, and a special dihydric phenol instead of toxic phosgene. -182336. However, a special dihydric phenol, 9,9-
There is only a description of bis(4-hydroxyphenyl)fluorenes. Also, obtaining polycarbonate from 2,2-bis(4-hydroxyphenyl)propane using triphosgene instead of the toxic phosgene was reported in Angew, Chem,
)dish.

922 (1987), German patent DE 344014
1, a reaction mechanism in which phosgene is generated has also been proposed.

On the other hand, in the transesterification reaction, a transesterification catalyst is added to diphenyl carbonate and an aromatic dihydroxy compound, and the prepolymer is combined while distilling off the phenol under heating and reduced pressure.Finally, the mixture is heated under high vacuum at 290'C High molecular weight polycarbonate is obtained by distilling off phenol by heating above (US Pat. No. 4,345,062).
Unlike other engineering plastics, high molecular weight polycarbonate has an extremely high melt viscosity, so it requires high temperatures of 290°C or higher, and high vacuum (10-2 Torr) to distill off phenol, which has a high boiling point.
It is difficult to industrialize the process due to the need for equipment, and it is known that residual phenol in the polycarbonate produced has an unfavorable effect on the hue and physical properties.

Furthermore, a method for producing aromatic polycarbonate by synthesizing a bisalkyl carbonate ester of an aromatic dihydroxy compound having an alkyl carbonate group at the end using a transesterification reaction and self-condensing this in the presence of a catalyst has been disclosed in Japanese Patent Application. It is disclosed in Sho 63-205318. This production method involves self-condensation in the absence of aromatic dihydroxy compounds, and the catalysts that can be used are Zn, A
I, Sn.

IIB, IIIB, I of the periodic table represented by Ti etc.
V.A.

It is described that the catalyst is selected from metal elements belonging to IVB and their compounds.

Furthermore, JP-A No. 63-223035 discloses a method for producing an aromatic polycarbonate by heating a bisalkyl carbonate of an aromatic dihydroxy compound to synthesize a prepolymer using a transesterification reaction. However, the catalyst used in the solid phase polymerization reaction to increase the molecular weight is not particularly described.

(Means for Solving the Problems) The present inventors used toxic phosgene by reacting a dialkyl carbonate with an aromatic dihydroxy compound in the presence of a highly active and special transesterification catalyst in the heathered yarn. We have now discovered that it is possible to obtain a colorless and transparent high molecular weight polycarbonate that essentially does not contain chlorine ions. That is, the present invention provides: (1) A method for producing polycarbonate, which comprises reacting a dialkyl carbonate and an aromatic dihydroxy compound in the presence of SbR1R2R3 or Sb2Xm as a transesterification catalyst.

(Here, R1, R2, R3 are an alkyl group, a phenyl group, an alkoxyl group, or a phenoxy group. X is O or 81m is 3,5.) (2) In the presence of 5b2RIR2R3 or Sb2Xm as a transesterification catalyst, A method for producing polycarbonate, characterized in that polycarbonate is obtained via an oligomer of an aromatic dihydroxy compound sealed with a dialkyl carbonate obtained from a dialkyl carbonate and an aromatic dihydroxy compound.

(3) A method for producing a polycarbonate in which the aromatic dihydroxy compound described in (1) or (2) is represented by (I), (II), (III), or (IV).

(R1, R2, Ra, R4 are hydrogen or have 1 to 8 carbon atoms
(4) The polycarbonate copolymer described in (1) or (2) or (3) above, where X is a halogen atom and n = 0 to 4). Manufacturing method.

(5) (1) or (2) or (3) or (4) above
The described SbR1R2R3 or Sb2Xm is Sb2O
The present invention relates to a polycarbonate manufacturing method comprising the polycarbonate manufacturing method No. 3.

Typical examples of dialkyl carbonates that can be used in the present invention include dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, di-t-butyl carbonate, di-t-butyl carbonate, cyamyl carbonate, dihexyl carbonate, dihe Examples include butyl carbonate, dioctyl carbonate, dicyclopropyl carbonate, etc., but dimethyl carbonate is preferred, since the alkyl group that is eliminated when forming a carbonate bond has a low boiling point and is made from inexpensive methyl alcohol. Moreover, the following compounds are mentioned as representative examples of aromatic dihydroxy compounds. Aromatic dihydroxy compounds classified into general formula (I) include 2,2-bis-(4-hydroxyphenyl)propane, 2,2-bis-(4-
hydroxyphenyl)butane, 2,2-bis-(4-hydroxyphenyl)-4-methylpentane, 2,2-bis-(4-hydroxyphenyl)octane, 4.4'
-dihydroxy-2,2,2-triphenylethane, 2
, 2-bis-(3,5-dibromo-4-hydroxyphenyl)propane, and the like. As a bisphenol classified into general formula (II), 2,2-bis-(4-
hydroxy-3-isopropylphenyl)bropan,
2,2-bis-(4-hydroxy-5-sec, butylphenyl)propane, 2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)propane, 2,2-bis-(4-hydroxy -3-tert-butylphenyl)propane and the like. As a bisphenol classified into general formula (III), 1.1'-bis-(4-
hydroxyphenyl)-P-diisopropylbenzene,
1.1'-bis-(4-hydroxyphenyl)-m-
Examples include diisopropylbenzene. General formula (I
Examples of bisphenols classified as V) include 1,1-bis(4-hydroxyphenyl)cyclohexane. Furthermore, general formulas (I), (II), (III),
It is also possible to produce a copolymerized polycarbonate in which two or more dihydric phenols selected from (IV) are combined.

In addition, SbR1R2R used as a transesterification catalyst
As a representative example of 3 or Sb2Xm, 5b(OCH
3) 3,5b(C6H5)3,5b(CH3COO
)3, 5b203.

Examples include Sb2O5 and 5b2s5. It is also possible to use two or more of these catalysts in combination. Preferably, Sb2O3 is used, in which the high molecular weight polycarbonate obtained is colorless and transparent. Further, the amount of the catalyst to be used can be in the range of 1X10-5 to 1 mol, preferably 5 X 10-' to 5 X 10-1 mol, based on the aromatic dihydroxy compound used as the raw material. If the amount is less than 5×10 4 mol, the polymerization rate will be slow, causing coloration, and if it exceeds 5×10 −1 mol, the catalyst remaining in the polycarbonate obtained will be a factor that adversely affects the physical properties, such as a decrease in mechanical properties.

Regarding the reaction conditions for carrying out the polycondensation reaction in the method of the present invention, dialkyl carbonate is used in an amount of 0.5 to 10 times the mole of the aromatic dihydroxy compound as a raw material, preferably 1 to 5 times the mole. It is. If it is less than 1 mole, the degree of polymerization will not increase stoichiometrically, and if it exceeds 5 moles, the amount of excess dialkyl carbonate to be removed from the system will increase, which is disadvantageous in terms of equipment. General reaction conditions include adding 1.5 times the molar amount of dimethyl carbonate to 1 mole of 2,2-bis(4-hydroxyphenyl)propane under nitrogen.
After charging into a US316 reactor and adding I x 10-2 moles of Sb2O3 as a catalyst, the mixture was reacted for 1 hour in the range of 90°C to 320°C under normal pressure or increased pressure to remove by-produced methanol and excess dimethyl. Remove carbonate from the system. Furthermore, under reduced pressure in the range of 200 to 280'C
A high molecular weight polycarbonate can be obtained by reacting for up to 3 hours and removing methanol from the system.

In addition, when obtaining a high molecular weight polycarbonate via an oligomer of an aromatic dihydroxy compound sealed with a dialkyl carbonate, two times the molar amount of dimethyl carbonate per mole of 2,2-bis(4-hydroxyphenyl)propane is added to nitrogen. Charge the reactor of 5US316 below,
After adding I x 10-2 mol of Sb2O3 as a catalyst, the mixture is reacted at normal pressure or under increased pressure in the range of 90°C to 250°C for 10 to 30 minutes, and by-produced methanol and excess dimethyl carbonate are removed from the system. The weight average molecular weight (in terms of polystyrene) of the above oligomer obtained by removing the
,000 to 18,000, preferably 1,000 to 18,000.
It ranges from 500 to 15,000. If it is less than 1,500, the time for post-condensation under reduced pressure will be prolonged, which will adversely affect the hue of the polycarbonate obtained, and if it exceeds 15,000, the reaction time will be prolonged under normal pressure or increased pressure, which is preferable (I/). .

The present invention will be explained in detail below using examples, but is not limited to these examples in any way.)

(Example) Example 1 2,2-bis(4
-Hydroxyphenyl)propane (228 parts by weight), 157 parts by weight of dimethyl carbonate, and 1.17 parts by weight of 5b203 were charged, and after performing nitrogen substitution by pressure-atmospheric pressure operation, the reaction temperature was raised to 180°C and under stirring. at a pressure of 8K
The reaction was carried out for 1 hour while maintaining the temperature at 1 cm2. At that time, the produced methyl alcohol and excess dimethyl carbonate were distilled off. The reaction rate of 2,2-bis(4-hydroxyphenyl)propane was 96%.

Next, the generated oligomer (weight average molecular weight: 1,80
0) was placed in a round bottom reaction vessel at atmospheric pressure and gradually heated to 240-250'C while reducing the pressure. After about 3 hours, the temperature was finally raised to 280'C at a pressure of about 5 mmHg for 20
Processed for minutes. As the methyl alcohol was removed, the liquid in the system became viscous. The obtained polymer was clear and colorless, and gel permeation chromatography revealed that it had a weight average molecular weight of 42,300 (in terms of polystyrene).

Example 2 Aromatic dihydroxy compound 2,2-bis(4-hydroxyphenyl)propane 11 was prepared in the same manner as in Example 1.
4 parts by weight, 145 parts by weight of 4.4'-dihydroxy-2,2,2-triphenylethane, 157 parts by weight of dimethyl carbonate, and 1.17 parts by weight of Sb2Os were reacted in the same manner as in Example 1. Average molecular weight: 1,400) was obtained, placed in a round bottom reaction vessel at atmospheric pressure, and gradually heated to 250-260°C while reducing pressure. After about 3 hours, the temperature was finally raised to 280°C under a pressure of about 4 mmHg and treated for 20 minutes. The obtained polymer was clear and colorless, and gel permeation chromatography revealed that it had a weight average molecular weight of 37,000 (in terms of polystyrene). In addition, 2
．． 2-bis(4-hydroxyphenyl)propane and 4,
It turned out to be a 1:1 polycarbonate of 4'-dihydroxy-2,2,2-triphenylethane. Furthermore, as measured by a differential thermal analyzer, the glass transition temperature was 166°C.
Met.

Example 3 2,2-bis(4
-Hydroxyphenyl)propane (228 parts by weight), 117 parts by weight of dimethyl carbonate, and 1.17 parts by weight of 5b203 were charged and nitrogen substitution was performed by pressure-normal pressure operation,
The reaction temperature was raised to 200°C and the pressure was 10K under stirring.
g/cm2 and the reaction was carried out for 1 hour. At that time, the stored methyl alcohol and excess dimethyl carbonate were distilled off. Next, the pressure was returned to normal, and the pressure was reduced to remove by-products while gradually heating to 240 to 250'C. After about 2 hours, the temperature was finally raised to 290'C under a pressure of about 4 mmHg, and treatment was carried out for 25 minutes. The weight average molecular weight of the obtained polymer was determined by gel permeation chromatography to be 36.000 (in terms of polystyrene).
It turned out to be.

Comparative Example 1 A reaction was carried out in the same manner as in Example 1 by adding 3.40 parts by weight of tetrabutyl titanate instead of Sb2O3 as a catalyst, but the liquid taken out was reddish brown and the molecular weight did not increase.

(Effects of the Invention) The present invention overcomes the drawbacks of the conventional method for producing polycarbonate using a transesterification catalyst, and by using an effective catalyst in a new synthesis method, industrially efficient polycarbonate can be produced. can be manufactured.

Claims (5)

[Claims] (1) SbR_1R_2R_3 as a transesterification catalyst
Alternatively, a method for producing polycarbonate, which comprises reacting a dialkyl carbonate and an aromatic dihydroxy compound in the presence of Sb_2Xm. (Here, R_1, R_2, R_3 are an alkyl group, a phenyl group, an alkoxyl group, or a phenoxy group.X
is O or S, m is 3,5. ) (2) SbR_1R_2R_3 as a transesterification catalyst
or Sb_2Xm(R_1, R_2, R_3 and
, m is the same as in (1) above), the polycarbonate is obtained via an oligomer of a dialkyl carbonate-capped aromatic dihydroxy compound obtained from a dialkyl carbonate and an aromatic dihydroxy compound. Manufacturing method. (3) The aromatic dihydroxy compound according to claim 1 or 2 is (I), (II), (III), (IV)
A method for manufacturing polycarbonate represented by ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (III) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ( IV) (R_1, R_2, R_3, R_4 are hydrogen or have 1 carbon number
~8 linear or branched alkyl group, or phenyl group, where X is a halogen atom and n = 0 to 4) (4) A polycarbonate obtained by reacting the dialkyl carbonate according to claim 1 or 2 with at least two or more aromatic dihydroxy compounds selected from the aromatic dihydroxy compounds according to claim 3. Polymer manufacturing method. (5) SbR_1R_2R_3 or Sb_2 according to claim 1 or 2 or 3 or 4
A method for producing polycarbonate in which Xm is Sb_2O_3.