CN101125917A - Method for preparing polycarbonate by melt transesterification and catalyst used therefor - Google Patents

Abstract

The invention relates to a method for preparing polycarbonate by melt transesterification and a catalyst used therein, belonging to the technical field of polycarbonate preparation. The composite catalyst of the present invention comprises: an acetylacetonate-based metal complex and a nitrogen-containing basic compound; a method for preparing polycarbonate, through which an aromatic dihydroxy compound and a carbonic acid diester are melted and transesterified, and the catalyst used For the composite catalyst mentioned above. For every 1 mole of dihydroxy compound, the amount of acetylacetonate-based metal complex is 10 ^-8 to 10 ^-4 moles, and the amount of nitrogen-containing basic compound is 10 ^-5 to 10 ^-2 moles. The reaction is performed at a temperature ranging from 100°C to 320°C. The exchange reaction is gradually or stepwise decompressed, from 133 mbar to below 1 mbar, and the monohydric phenol is continuously distilled. The invention can produce polycarbonate with good hue and less branched cross-linking, and is very beneficial to the preservation and post-processing of polycarbonate products.

Description

Method for preparing polycarbonate by melt transesterification and catalyst used therefor

technical field

The invention belongs to the technical field of polycarbonate preparation, and further relates to a method for preparing polycarbonate by melt transesterification and a catalyst used therein.

Background technique

Polycarbonate is known for its excellent transparency, impact resistance, heat resistance, dimensional stability, non-toxicity, weather resistance, electrical insulation, radiation sterilization resistance and mechanical properties. It is a thermoplastic with excellent comprehensive properties. engineering plastics.

The traditional preparation process of aromatic polycarbonate by phosgene method is to mix the aqueous solution of sodium salt of aromatic dihydroxy compound with dichloromethane dissolved in phosgene, and obtain polycarbonate through interfacial polycondensation. The advantage of this method is that the production equipment and The condition requirements are simple, and the reaction can be carried out at normal temperature and pressure, but the post-treatment process is complicated, and the salt needs to be washed with water, and the dichloromethane solvent must be removed. Public health and environmental interests are at odds.

The non-phosgene preparation process uses aromatic dihydroxy compounds and carbonic acid diesters to directly perform melt transesterification under the action of a catalyst to obtain aromatic polycarbonate. The advantage of this method is that it does not use highly toxic phosgene and solvent dichloro Methane, no solvent removal and water washing desalination process, the process is simple, greatly reducing the degree of pollution to the environment. Although this method has relatively strict requirements in terms of raw material purity, production equipment, and process technology, it has become the direction of today's polycarbonate industrialization because of its many advantages.

In the process of preparing polycarbonate by melt transesterification, in order to prepare high molecular weight polycarbonate, the reaction system must withstand high temperature and high vacuum history, especially as the molecular weight of the product increases, the viscosity of the system increases, mass transfer, heat transfer The condition deteriorates and local overheating is difficult to control, leading to the formation of branched cross-linked products (as shown in formula 1) and polycarbonate coloration.

Selecting an appropriate catalyst and dosage not only enables the transesterification reaction to proceed at a faster rate at a lower temperature, but also minimizes the amount of catalyst residue in the polymerization product to avoid negative effects on the application performance of the product.

Patent documents WO 9736292 and EP96719815 disclose nitrogen-containing basic compounds (such as tetramethylammonium hydroxide) and alkali metal compounds or alkaline earth metal compounds (such as sodium hydroxide) as catalysts.

Patent document WO 0037531 discloses alkali metal/alkaline earth metal phosphites and amines, tetraalkylammonium salts, guanidines as catalysts.

Japanese patent documents JP9-241371 and JP11-5837 disclose the use of lanthanum alkoxides and lanthanum and cerium crown ether complexes as catalysts.

There are still many catalysts or catalyst systems reported in patent documents at present. For example,

(1) Tetramethylammonium hydroxide (Me ₄ NOH and its aqueous solution) system

Me ₄ NOH, Me ₄ NOH+NaOH, Me ₄ NOH+H ₃ BO ₃ , Me ₄ NOH+NaOH+H ₃ BO ₃ , Me ₄ NOH+NaHCO ₃ , Me ₄ NOH+NaHCO ₃ +H ₃ BO ₃ , Me ₄ NOH+BPA disodium salt, Me ₄ NOH+BPA disodium salt+Al(OEt) ₃ , Me ₄ NOH+BPA disodium salt+Si(OEt) ₄ , Me ₄ NOH+Al(OH) ₃ , Me ₄ NOH+Ph ₄ P ⁺ BPh ₄ ^- , Me ₄ NOH+5-phenyltetrazole, Me ₄ NOH+Cs ₂ CO ₃ ;

(2) Bisphenol A sodium salt system

BPA disodium salt, BPA disodium salt + 2,3-dihydroxy-2-methylbenzofuran, BPA disodium salt + Al(OEt) ₃ , BPA disodium salt + phenyl octyl sulfonate;

(3) Cesium carbonate (Cs ₂ CO ₃ ) system

Cs ₂ CO ₃ , Cs ₂ CO ₃ +(Et ₄ P) ₂ SO ₄ , Cs ₂ CO ₃ +(Bu ₄ P) ₂ CO ₃ , Cs ₂ CO ₃ +H ₃ PO ₃ ;

(4) Borohydride system

KBH ₄ , KBH ₄ +(EtO) ₂ P(O)Ph, Na ₂ B ₁₀ H ₁₀ , Na ₂ B ₁₂ H ₁₂ , KBH ₄ +2-methylimidazole;

(5) Beryllium oxide or beryllium hydroxide system

BeO or Be(OH) ₂

These catalysts all have certain effects in the preparation of polycarbonate, but they do not always produce satisfactory results in suppressing side reactions and improving hue.

Contents of the invention

One of the purposes of the present invention is to provide a new method for transesterification, and the second purpose is to provide a catalyst for transesterification.

The composite catalyst for polycarbonate prepared by melt transesterification method of the present invention comprises: acetylacetonate-based metal complexes and nitrogen-containing basic compounds.

The ligands in the acetylacetonate-based metal complexes are selected from acetylacetone, 1,1,1-trifluoroacetylacetone, 1,1,1,5,5,5-hexafluoroacetylacetone, 4,4,4-fluoro -1-(2-thienyl)-1,3-butanedione, 2,4-hexanedione, 3-ethyl-2,4-pentanedione, 6-methyl-heptanedione; preferably acetyl Acetonyl.

The metal in the acetylacetonate-based complex is selected from aluminum, chromium, zirconium, iron, copper, cobalt, titanium, manganese, tweezers, vanadium, zinc, and lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium of the lanthanides , terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium; preferably lanthanum, cerium, samarium and europium.

Preferred acetylacetonate metal complexes have the general formula:

or M(acac) _n xH ₂ O

Wherein: M is one of the above-mentioned metal elements, preferably selected from lanthanum, cerium, samarium and europium in lanthanides; n is the number of ligands, 2 to 4, generally 3; x is the number of crystal water, Between 2 and 8, generally 3 to 6.

The above-mentioned nitrogen-containing basic compound has any one of the following general formulas:

R ¹ R ² R ³ R ⁴ NOH(I),

Ar _n R _4-n NOH(II),

R _n NH _3-n (III),

R ₄ NBH ₄ (IV),

R ₄ NBPh ₄ (V),

Wherein: in general formula (I), R is an alkyl group; The compound represented by general formula (I) is such as tetramethyl ammonium hydroxide (abbreviation TMAH), tetraethyl ammonium hydroxide, tetrabutyl ammonium hydroxide;

In the general formula (II), Ar is an aryl group, R is an alkyl group, and n is the number of aryl groups; the compound represented by the general formula (II) is such as trimethylbenzyl ammonium hydroxide;

In the general formula (III), R is an alkyl group or an aryl group, and n is the number of substituents;

In the general formula (IV), R is an alkyl group or an aryl group; compounds represented by the general formula (III) such as tertiary amines: trimethylamine, triethylamine, triphenylamine, dimethylbenzylamine (PhCH ₂ (Me) ₂ N); secondary amines: dimethylamine, diethylamine, diphenylamine, primary amines: methylamine, ethylamine, aniline;

In the general formula (V), R is an alkyl group or an aryl group; the compounds represented by the general formula (V) are, for example, tetramethylamine tetraphenylborate and tetrabutylmethylamine tetraphenylborate.

The nitrogen-containing basic compounds usable in the present invention also include pyridine and pyridine derivatives, imidazole or imidazole derivatives, quinoline or quinoline derivatives. Representative examples such as pyridine, 2-aminopyridine, 2-hydroxypyridine, 2-methoxypyridine, 2-dimethylaminopyridine, 4-aminopyridine, 4-hydroxypyridine, 4-methoxypyridine, 4- Diethylaminopyridine; imidazole, 2-methylimidazole, 2-methoxyimidazole, 2-dimethylaminoimidazole, 2-mercaptoimidazole, benzimidazole, 4-methylimidazole; quinoline, aminoquinoline wait.

The method for preparing polycarbonate by melt transesterification according to the invention, the reactants are aromatic dihydroxy compound and carbonic acid diester, the catalyst is the composite catalyst mentioned above, and the polycarbonate is produced by melt transesterification. The catalyst used is a composite catalyst, which is dissolved or dispersed in the molten reaction system. The acetylacetonate-based metal complex, one of the components of the composite catalyst, is used in an amount of 10 ^-8 to 10 ^-4 moles, preferably 10 ^-7 to 10 ^-6 moles per 1 mole of the dihydroxy compound in the reactant system . The nitrogen-containing basic compound, one of the composite catalyst components, is used in an amount of 10 ^-5 to 10 ^-2 moles, preferably 10 ^-4 to 10 ^-3 moles per 1 mole of the dihydroxy compound in the reaction system.

The catalyst can be used both in solid form and in solution, for example in water or a water-ethanol solvent; both catalysts can be used alone or in admixture; both catalysts can be Add them all at once, or add them in batches according to the reaction process.

The transesterification reaction is carried out at a temperature ranging from 100°C to 320°C, preferably from 180°C to 300°C. During the transesterification reaction, the monohydric phenol is continuously distilled from the absolute atmospheric pressure to below 1 mbar, preferably from 133 mbar to below 1 mbar, under reduced pressure gradually or in stages.

Aromatic dihydroxy compounds as raw materials for transesterification include:

(1) Bis(hydroxyaryl) chain/cycloalkanes

Such as 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, bis(4-hydroxyphenyl) Methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)pentane, 2,2 -Bis(4-hydroxyphenyl)octane, bis(4-hydroxyphenyl)benzenemethane, 1,1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl) ) cyclohexane.

(2) Dihydroxyaryl ethers

Such as 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-xylene ether.

(3) Dihydroxydiaryl (oxide) sulfones

Such as 4,4'-dihydroxydiphenylsulfoxide, 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfoxide; 4,4'-dihydroxydiphenylsulfone, 4,4'- Dihydroxy-3,3'-dimethyldiphenylsulfone.

(4) Bisphenol compounds

Such as 2,2-dihydroxybiphenyl, 2,6-dihydroxybinaphthyl, 2,7-dihydroxybinaphthyl, 1,1'-dihydroxy-4,4'-binaphthyl, hydroquinone, m- Hydroquinone.

Among them, bisphenol A (abbreviated as BPA) is preferred.

Carbonic acid diester compounds for transesterification raw materials include:

Diphenyl carbonate, xylyl carbonate, dichlorophenyl carbonate, dinitrophenyl carbonate, dinaphthyl carbonate, diethyl carbonate, dimethyl carbonate, dibutyl carbonate.

Among them, diphenyl carbonate (abbreviated as DPC) is preferable.

In the present invention, the cocatalyst nitrogen-containing basic compound can be decomposed or volatilized at a temperature of 130°C to 300°C, and the addition amount of the catalyst acetylacetonate-based metal complex is in a specific range, so that it can produce both good color and less Branched and cross-linked polycarbonate is also very beneficial to the preservation and post-processing of polycarbonate products.

Detailed ways

In the embodiment of specific embodiment, adopt the method of the present invention to prepare bisphenol A type polycarbonate by bisphenol A and diphenyl carbonate, the monomer proportioning ratio is substantially equimolar ratio, preferably molar ratio is 1.0 to 1.2, most 1.02 to 1.10 is preferred, and the reaction is carried out in stages. In the first stage, at least one nitrogen-containing basic compound is added to the reactant system as a catalyst, and the amount used is 10 ^-5 to 10 ^-2 moles, preferably 10 ^-4 to 10 ^-3 moles per 1 mole of bisphenol A . Then in the second stage, at least one acetylacetonate-based metal complex catalyst is added in an amount of 10 ^-8 to 10 ^-4 moles, preferably 10 ^-7 to 10 ^-6 moles per 1 mole of bisphenol A. Of course, the composite catalyst used can also be added at one time when the monomers are fed.

In the first stage of the reaction, the reaction temperature is carried out at 250° C. or lower, the pressure is from atmospheric pressure to about 10 mbar absolute pressure, and the time is about 1 hour to 3 hours, preferably 1.5 hours to 2.5 hours. The viscosity-average molecular weight of the stage oligomeric polycarbonate reaches about 4000 to 8000; in the second stage of the reaction, the reaction temperature is carried out above 250 ° C, the pressure absolute pressure is about 1 mbar or below, and the time is about 1 hour to 3 hours, Preferably 1.5 hours to 2.5 hours, at this stage the viscosity average molecular weight of the high molecular weight polycarbonate reaches about 10,000 to 25,000.

Example 1

The reaction was carried out in a stirred nickel metal reaction vessel equipped with a non-leakage magnetic coupling drive. The vacuum system is connected to the reactor through the phenol collection bottle and the phenol distillation condenser. The pressure of the reaction system is jointly controlled by the vacuum pump and the nitrogen cylinder introduced into the downstream of the phenol collection bottle. U-type mercury pressure is used for high pressure (atmospheric pressure to 50 mbar). Gauge measurement, low pressure (50 mbar to 1.333 mbar and below) with a Maxwell rotary vacuum gauge. The temperature of the reaction system is heated and controlled by circulating heat transfer oil. A discharge port is provided at the bottom of the reactor.

Add 600.0 g (2.628 mol) of solid bisphenol A (Japan GE Plastics Co., Ltd.), 602.4 g (2.812 mol) of solid diphenyl carbonate (Shanghai Shenju Chemical Factory) and 602.4 g (2.812 mol) of solid diphenyl carbonate/bisphenol A in the reaction kettle successively. =1.07 (mol/mol), then the lid of the kettle is closely connected with the body of the kettle, and after sealing, replace the air in the system with high-purity nitrogen for three times, and heat the heat transfer oil to gradually increase the temperature of the reaction materials at close to or slightly lower than atmospheric pressure. Start stirring after 120°C, add catalyst-containing water or water-ethanol solution at 180°C, add 5.0×10 ^-7 mol La(acac) ₃ to 1 mol of bisphenol A. The pressure was reduced to 133.3 mbar within 5 minutes, the reaction temperature was raised to or maintained at 180°C, and the timing was started for 60 minutes, during which phenol was continuously distilled out; then the temperature was raised to 220°C within 5 minutes, and the pressure Decrease to 40.0 mbar and hold for 60 minutes; then increase the temperature to 260 °C within 5 minutes, and reduce the pressure to 20.0 mbar, and maintain for 60 minutes; finally increase the temperature to 280 °C within 5 minutes and reduce the pressure to 1.0 About millibar, keep 30 minutes, the reaction ends. Discharge the material from the discharge port under the nitrogen atmosphere under the protection of the bottom of the kettle, and take samples for analysis.

In the above examples, the obtained polycarbonates were subjected to physical property measurements by the following methods.

(1) Viscosity average molecular weight

Measured with Ubbelohde viscometer in dichloromethane (0.5g/dL) at 20°C, the calculation formula of viscosity average molecular weight _Mv is:

[η]=1.11×10 ^-4 M _v ^0.82

(2) Hue

Expressed in Hue index. Utilize Japan Shimadzu UV-160A ultraviolet spectrophotometer, under wavelength 380nm, absorption cell length 10mm, measure the absorbance A ₃₈₀ of the dichloromethane solution (1g/10mL) of polycarbonate, deduct its absorbance A ₅₈₀ at 580nm, To evaluate the degree of coloring of polycarbonate, namely: Hue index = A ₃₈₀ -A ₅₈₀ .

(3) Branch content

The polycarbonate containing the branched product is completely alkaline hydrolyzed, and the hydrolyzate (formula 2) is subjected to high-performance liquid chromatography (HPLC) to determine the amount of the branched product.

Comparative Example 1

The same procedure as in Example 1 was performed to prepare polycarbonate, except that 5.0×10 ⁻⁷ mol of NaOH was used as a polymerization catalyst for 1 mol of bisphenol A.

Comparative Example 2

Except for using 5.0×10 ⁻⁷ mol of bisphenol A sodium salt as a polymerization catalyst for 1 mol of bisphenol A, the same procedure as in Example 1 was performed to prepare polycarbonate.

Comparative Example 3

Except for using 5.0×10 ⁻⁷ mol Cs ₂ CO ₃ as a polymerization catalyst for 1 mol of bisphenol A, the same procedure as in Example 1 was performed to prepare polycarbonate.

Example 2

Except for using 1.0×10 ⁻⁸ mol La(acac) ₃ as a polymerization catalyst for 1 mol of bisphenol A, the same procedure as in Example 1 was performed to prepare polycarbonate.

Example 3

Except for using 1.0×10 ⁻⁶ mol La(acac) ₃ as a polymerization catalyst for 1 mol of bisphenol A, the same procedure as in Example 1 was performed to prepare polycarbonate.

Example 4

The same procedure as in Example 1 was performed to prepare polycarbonate, except that 5.0×10 ^-4 mol TMAH and 5.0×10 ^-7 mol La(acac) ₃ were used as polymerization catalysts for 1 mol of bisphenol A.

Comparative Example 4

Except for using 5.0×10 ⁻⁴ mol TMAH as a polymerization catalyst for 1 mol of bisphenol A, the same procedure as in Example 1 was performed to prepare polycarbonate.

Comparative Example 5

The same procedure as in Example 1 was performed to prepare polycarbonate, except that 5.0×10 ⁻⁴ mol TMAH and 5.0×10 ⁻⁷ mol NaOH were used as polymerization catalysts for 1 mol of bisphenol A.

By analyzing the viscosity-average molecular weight, branched content and hue of the polycarbonates prepared in Examples 1-4 and Comparative Examples 1-5, the results are listed in Table 1 below.

Table 1

Example Catalyst Polycarbonate catalyst Dosage mol/molBPA M _v Branch content ppm Hue index × 100 Example 1 La(acac) ₃ 5.0×10 ^-7 17040 190 0.3 Comparative example 1 NaOH 5.0×10 ^-7 18950 470 0.6 Comparative example 2 Sodium BPA 5.0×10 ^-7 18550 410 0.6 Comparative example 3 Cs ₂ CO ₃ 5.0×10 ^-7 18010 220 0.3 Example 2 La(acac) ₃ 1.0×10 ^-8 16090 170 0.3 Example 3 La(acac) ₃ 1.0×10 ^-6 17980 250 0.4 Example 4 TMAHLa(acac) ₃ 5.0×10 ^-4 5.0×10 ^-7 20050 210 0.5 Comparative example 4 TMAH 5.0×10 ^-4 17130 200 0.5 Comparative example 5 TMAHNaOH 5.0×10 ^-4 5.0×10 ^-7 20890 550 0.7

The data shows that the stronger the alkalinity of the selected catalyst, such as NaOH and BPA sodium salt in the comparative example, can obtain a faster reaction speed, but the side reactions will intensify thereupon, which will certainly affect the color and luster and application performance of the product. Negative Effects.

In the examples, determine the composite catalyst system selected for this reaction, the amount of TMAH is 10 ^-4 (mol ratio) of the polymerized monomer bisphenol A, and La(acac) ₃ is 10 ^-7 of the polymerized monomer bisphenol A (mol ratio), it has sufficient catalytic effect, and the polycarbonate product obtained under the amount of the catalyst has a good hue, and the branched content in the polycarbonate product can be significantly reduced.

The above embodiments are explanations or descriptions of the technical solutions to be protected in the present invention, but it should be clear that the present invention is not limited to these embodiments, therefore, the protection scope of the present invention is still subject to the technical solutions described in the claims.

Claims (17)

1. a melt transesterification process prepares the polycarbonate composite catalyst, comprising: acetylacetone based metal complexes and nitrogenous basic cpd.

2. a kind of according to claim 1 melt transesterification process prepares the polycarbonate composite catalyst, it is characterized in that, the part in the described acetylacetone based metal complexes is selected from methyl ethyl diketone, 1,1,1-trifluoroacetylacetone, 1,1,1,5,5,5-hexafluoroacetylacetone, 4,4,4-fluoro-1-(2-thienyl)-1,3-dimethyl diketone, 2,4-hexanedione, 3-ethyl-2, any in 4-diacetylmethane, the 6-methyl-heptadione.

3. a kind of according to claim 1 melt transesterification process prepares the polycarbonate composite catalyst, it is characterized in that, metallic element in the described acetylacetone based metal complexes is aluminium, chromium, zirconium, iron, copper, cobalt, titanium, manganese, nickel, vanadium, zinc, and any in the lanthanum of lanthanon, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and the lutetium.

4. a kind of according to claim 1 melt transesterification process prepares the polycarbonate composite catalyst, it is characterized in that, described acetylacetone based metal complexes has following general formula:

Or M (acac) _nXH ₂O

Wherein: M is metallic element aluminium, chromium, zirconium, iron, copper, cobalt, titanium, manganese, nickel, vanadium, zinc, and any in the lanthanum of lanthanon, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and the lutetium;

N is the part number, gets 2～4;

X is the crystal water number, between 2～8.

5. prepare the polycarbonate composite catalyst as a kind of melt transesterification process as described in the claim 4, it is characterized in that, M is any in metallic element lanthanum, cerium, samarium, the europium; N is for getting 3; X is between 3～6.

As claim 1 to 5 as described in any one a kind of melt transesterification process prepare the polycarbonate composite catalyst, it is characterized in that described nitrogenous basic cpd has any in the following general formula:

R ¹R ²R ³R ⁴NOH(I)，

Ar _nR _4-nNOH(II)，

R _nNH _3-n(III)，

R ₄NBH ₄(IV)，

R ₄NBPh ₄(V)，

Wherein: in the general formula (I), R is an alkyl;

In the general formula (II), Ar is an aryl, and R is an alkyl;

In the general formula (III), R is an alkyl or aryl, and n is the substituting group number;

In the general formula (IV), R is an alkyl or aryl;

In the logical formula V, R is an alkyl or aryl.

As claim 1 to 5 as described in any one a kind of melt transesterification process prepare the polycarbonate composite catalyst, it is characterized in that described nitrogenous basic cpd is selected from any in Tetramethylammonium hydroxide, tetraethyl ammonium hydroxide, TBAH, trimethyl benzyl ammonium hydroxide, Trimethylamine 99, triethylamine, triphenylamine, dimethyl benzyl amine, dimethylamine, diethylamine, pentanoic, methylamine, ethamine, aniline, hydroboration tetramethylammonium, hydroboration four butylamine, tetraphenyl borate tetramethylammonium, the tetraphenyl borate four fourth methylamines.

As claim 1 to 5 as described in any one a kind of melt transesterification process prepare the polycarbonate composite catalyst, it is characterized in that described nitrogenous basic cpd is selected from any in pyridine, pyridine derivate, imidazoles, imdazole derivatives, quinoline, the quinoline.

9. prepare the polycarbonate composite catalyst as any melt transesterification process as described in the claim 8, it is characterized in that described nitrogenous basic cpd is selected from any in pyridine, 2-aminopyridine, 2 hydroxy pyrimidine, 2-methoxypyridine, 2-dimethyl aminopyridine, 4-aminopyridine, 4-pyridone, 4-methoxypyridine, 4-diethyl amino yl pyridines, imidazoles, glyoxal ethyline, 2-methoxyl group imidazoles, 2-dimethylamino imidazoles, 2-mercaptoimidazole, benzoglyoxaline, 4-methylimidazole, quinoline, the quinolylamine.

10. a melt transesterification process prepares the method for polycarbonate, it is characterized in that: carry out melting state transesterification reaction by aromatic dihydroxy compound and carbonic diester, used catalyzer is the described catalyzer of claim 1, catalyst dissolution or be scattered in the frit reaction system; With respect to per 1 mole of dihydroxy compound, acetylacetone based metal complexes usage quantity is 10 in the catalyzer ^-8～10 ^-4Mole; With respect to per 1 mole of dihydroxy compound, nitrogenous basic cpd usage quantity is 10 in the catalyzer ^-5～10 ^-2Mole; Transesterification reaction is carried out in 100 ℃～320 ℃ temperature range; Permutoid reaction is gradually or split reduction, from 133 millibars to below 1 millibar, constantly steam monohydric phenol; Used composite catalyst can once add when monomer feed or add in reaction process in batches.

11. prepare the method for polycarbonate, it is characterized in that the acetylacetone based metal complexes that catalyst system therefor one of is formed is selected from La (acac) as a kind of melt transesterification process as described in the claim 10 ₃The nitrogenous basic cpd of one of catalyst system therefor composition is selected from Tetramethylammonium hydroxide, tetraethyl ammonium hydroxide, TBAH, trimethyl benzyl ammonium hydroxide, Trimethylamine 99, triethylamine, triphenylamine, dimethyl benzyl amine, dimethylamine, diethylamine, pentanoic, methylamine, ethamine, aniline, the hydroboration tetramethylammonium, hydroboration four butylamine, the tetraphenyl borate tetramethylammonium, tetraphenyl borate four fourth methylamines, pyridine, the 2-aminopyridine, 2 hydroxy pyrimidine, the 2-methoxypyridine, the 2-dimethyl aminopyridine, 4-aminopyridine, the 4-pyridone, 4-methoxypyridine, 4-diethyl amino yl pyridines, imidazoles, glyoxal ethyline, 2-methoxyl group imidazoles, 2-dimethylamino imidazoles, the 2-mercaptoimidazole, benzoglyoxaline, 4-methylimidazole, quinoline, any in the quinolylamine.

12. prepare the method for polycarbonate as a kind of melt transesterification process as described in the claim 10, it is characterized in that: transesterification reaction is carried out in 180 ℃～300 ℃ temperature range.

13. prepare the method for polycarbonate as a kind of melt transesterification process as described in the claim 10, it is characterized in that: transesterification reaction is carried out under the multistep condensation polymerization step in two or more stages, and catalyst system therefor adds fashionable in batches:

(1) in the fs of polycondensation, the compound that is selected from a kind of nitrogenous basic cpd at least is as catalyzer, and temperature of reaction is at 250 ℃ or more carry out under the low temperature, reaches 4000 to 8000 approximately in this stage oligomeric polycarbonate viscosity-average molecular weight;

(2) in the subordinate phase of polycondensation, a kind of acetylacetone based metal complexes is as catalyzer, and temperature of reaction is being carried out more than 250 ℃, reaches 10000 to 25000 approximately in this stage high-molecular-weight polycarbonate viscosity-average molecular weight.

14. prepare the method for polycarbonate as a kind of melt transesterification process as described in the claim 10, it is characterized in that: with respect to per 1 mole of dihydroxy compound, acetylacetone based metal complexes usage quantity is 10 ^-7～10 ^-6Mole; With respect to per 1 mole of dihydroxy compound, nitrogenous basic cpd usage quantity is 10 ^-4～10 ^-3Mole.

15. prepare the method for polycarbonate as a kind of melt transesterification process as described in the claim 10 to 14, it is characterized in that: aromatic dihydroxy compound is selected from two (hydroxyaryl) chain/naphthenic hydrocarbon, dihydroxy aryl oxide class, dihydroxyl diaryl (Asia) sulfone class, bisphenol cpd.

16. prepare the method for polycarbonate as a kind of melt transesterification process as described in the claim 15, it is characterized in that: aromatic dihydroxy compound is selected from 2, two (4-hydroxyphenyl) propane of 2-, 2, two (3, the 5-dimethyl-4-hydroxyphenyl) propane of 2-, two (4-hydroxyphenyl) methane, 1, two (4-hydroxyphenyl) ethane of 1-, 2, two (4-hydroxyphenyl) butane of 2-, 2, two (4-hydroxyphenyl) pentanes of 2-, 2, two (4-hydroxyphenyl) octanes of 2-, two (4-hydroxyphenyl) phenylmethane, 1, two (4-hydroxyphenyl) pentamethylene of 1-, 1, two (4-hydroxyphenyl) hexanaphthenes of 1-, 4,4 '-dihydroxy diphenyl ether, 4,4 '-dihydroxyl-3,3 '-dibenzyl ether, 4,4 '-dihydroxyl thionyl benzene, 4,4 '-dihydroxyl-3,3 '-dimethyl thionyl benzene, 4,4 '-dihydroxy diphenylsulphone, 4,4 '-dihydroxyl-3,3 '-diphenylsulfone dimethyl, 2,2-dihydroxybiphenyl, 2,6-dihydroxyl dinaphthalene, 2,7-dihydroxyl dinaphthalene, 1,1 '-dihydroxyl-4,4 '-dinaphthalene, Resorcinol, any in the Resorcinol.

17. as claim 10 to 14 as described in any one a kind of melt transesterification process prepare the method for polycarbonate, it is characterized in that: described carbonic diester compound is selected from any in diphenyl carbonate, carboxylol ester, the two chlorobenzene esters of carbonic acid, the two nitro phenyl esters of carbonic acid, carbonic acid dinaphthyl ester, diethyl carbonate, methylcarbonate, the dibutyl carbonate.