JP3033062B2 - Manufacturing method of aromatic polycarbonate - Google Patents

Description

The present invention relates to a method for producing an aromatic polycarbonate.

(Prior Art) In recent years, aromatic polycarbonates have been widely used in many fields as engineering plastics having excellent heat resistance, impact resistance, transparency, and the like. Various studies have hitherto been made on the method for producing the aromatic polycarbonate, and among them, an aromatic dihydroxy compound, for example, 2,2-bis (4-hydroxyphenyl) propane (hereinafter referred to as bisphenol A) and phosgene have been studied. Has been industrialized.

However, in the interfacial polycondensation method using phosgene, toxic phosgene must be used, the apparatus is corroded by chlorine-containing compounds such as by-produced hydrogen chloride and sodium chloride, and sodium chloride mixed in the resin. However, there is a problem that it is difficult to separate impurities that adversely affect the physical properties of the polymer.

On the other hand, as a method for producing an aromatic polycarbonate from an aromatic dihydroxy compound and a diaryl carbonate, for example, a melting method in which bisphenol A and diphenyl carbonate are transesterified in a molten state has been known for a long time. The present inventors have also disclosed in Japanese Patent Application Laid-Open No.
No. 25 discloses a method in which a dihydroxydiaryl compound and a diaryl carbonate are preliminarily polymerized under heating, crystallized, and then solid-phase polymerized. When diaryl carbonate synthesized by the phosgene method is used as a raw material in carrying out these methods, contamination with chlorine compounds poses a problem in terms of equipment corrosion and polymer physical properties as in the case of the above-mentioned interfacial polycondensation method. For example, Japanese Patent Application Laid-Open No.
No. 5722 describes a method for producing an aromatic polycarbonate by a melting method, in which the content of hydrolyzable chlorine in an aromatic dihydroxy compound and a diaryl carbonate, which are monomers, is 3 ppm or less. However, in the present invention, since the melt polymerization is performed using the transesterification catalyst, it was difficult to avoid the coloring of the polymer.

As a method for producing a diaryl carbonate, many studies have been made on transesterification of a dialkyl carbonate in the presence of phenol.However, according to JP-A-61-172852, in these methods, diaryl carbonate is contained in the diaryl carbonate. It is described that by-product impurities having a boiling point close to the above are mixed. Even when an aromatic carbonate is produced using a diaryl carbonate containing such impurities, there is a problem that the aromatic polycarbonate is colored.

(Problems to be Solved by the Invention) An object of the present invention is to overcome the drawbacks of the conventional phosgene method and to obtain a high-quality polycarbonate without coloring from an aromatic dihydroxy compound and a diaryl carbonate as raw materials. It was done as.

(Means for Solving the Problems) The present inventors have made intensive studies on a method for producing an aromatic polycarbonate using a transesterification reaction, and as a result, reacted an aromatic dihydroxy compound with a diaryl carbonate to produce an aromatic polycarbonate. In producing, no polymerization catalyst is used, chlorine content is 0.05ppm
The present inventors have found that the above-mentioned object can be achieved by using a diaryl carbonate having a content of xanthone of 10 ppm or less, which has led to the present invention.

 Hereinafter, the present invention will be described in detail.

In the present invention, the aromatic dihydroxy compound is represented by the formula (I): HO-Ar-OH (I) (wherein, Ar represents a divalent aromatic group).

The aromatic group Ar is preferably, for example, of the formula -Ar ¹ -Y-Ar ^2- (wherein Ar ¹ and Ar ² each independently have 5 carbon atoms.
Represents a divalent carbocyclic or heterocyclic aromatic group having from 1 to 30, and Y represents a divalent alkane group having from 1 to 30 carbon atoms. ) Is a divalent aromatic group represented by

In the divalent aromatic groups Ar ¹ and Ar ² , one or more hydrogen atoms are replaced with another substituent that does not adversely influence the reaction, for example,
Halogen atom, alkyl group having 1 to 10 carbon atoms, 1 to 1 carbon atom
It may be substituted by 10 alkoxy groups, phenyl groups, phenoxy groups, vinyl groups, cyano groups, ester groups, amide groups, nitro groups and the like.

Preferred specific examples of the heterocyclic aromatic group used in the present invention include an aromatic group having one or more ring-forming nitrogen, oxygen, or sulfur atoms.

The divalent aromatic group represents, for example, a group such as substituted or unsubstituted phenylene, substituted or unsubstituted naphthylene, substituted or unsubstituted biphenylene, and substituted or unsubstituted pyridylene. The substituent here is as described above.

A divalent alkane group has, for example, the formula: (Wherein, R ¹ , R ² , R ³ , and R ⁴ each independently represent hydrogen, carbon number 1 to
10 alkyl groups, C1 to C10 alkoxy groups, C5 to C10 cycloalkyl groups, C5 to C10
And a carbocyclic aralkyl group having 6 to 10 carbon atoms, and k represents an integer of 3 to 11. ) Is an organic group represented by

Such a divalent aromatic group includes, for example, a compound represented by the formula: (Wherein, R ⁵ and R ⁶ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 ring carbon atoms, or A phenyl group, wherein m and n are integers of 1 to 4;
Is 2 to 4, each R ⁵ may be the same or different. When n is 2 to 4, each R ⁶ may be the same or different. ).

Further, the divalent aromatic group Ar is represented by the formula -Ar ¹ -Z-Ar ^2- (wherein, Ar ¹ and Ar ² are as described above, and Z is a bond, or -O-, -CO-, _{-S -, - SO 2 -,} - SO -, - COO
—, —CON (R ¹ ) —, where R ¹ represents a divalent group as described above. ).

As such a divalent aromatic group, for example, (In the formula, R ⁵ , R ⁶ , m and n are as described above.)

In the prepolymer of the present invention, Ar is 2 as described above.
The monovalent aromatic group may be composed of a single kind, or may be composed of two or more kinds.

Particularly preferred are the residues of bisphenol A and substituted bisphenol A, of the formula Is included when 85 to 100 mol% of the whole Ar is contained.

In addition, the prepolymer of the present invention is about 0.
A trivalent aromatic group may be contained in the range of 01 to 3 mol%.

The diaryl carbonate used in the present invention has the general formula (II): (In the formula, Ar ³ represents a monovalent aromatic group.)

Ar ³ represents a monovalent represents a carbocyclic or heterocyclic aromatic group, in this Ar ^3, 1 or more hydrogen atoms, other substituents which do not adversely affect the reaction, for example, a halogen atom, It may be substituted by an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a phenyl group, a phenoxy group, a vinyl group, a cyano group, an ester group, an amide group, a nitro group, or the like.

Representative examples of the monovalent aromatic group Ar ³ include a phenyl group,
Examples include a naphthyl group, a biphenyl group, and a pyridyl group. These may be substituted with one or more substituents described above.

Preferred Ar ³ is, for example, And the like.

Representative examples of diaryl carbonates include: (Wherein, R ⁷ and R ⁸ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms,
An alkoxy group having 10; a cycloalkyl group having 5 to 10 ring carbon atoms; or a phenyl group;
When p is 2 or more, each R ⁷ may be different when p is 2 or more, and when q is 2 or more,
R ⁸ may be different. ), Substituted or unsubstituted diphenyl carbonates.

Of these diphenyl carbonates, symmetric diaryl carbonates such as diphenyl carbonate, ditolyl carbonate, and lower alkyl-substituted diphenyl carbonates such as di-t-butylphenyl carbonate are preferred, but the diaryl carbonate having the simplest structure is particularly preferred. Diphenyl carbonate is preferred.

These diaryl carbonates may be used alone or in combination of two or more.

In the present invention, the chlorine content in the diaryl carbonate is 0.05 ppm or less. When the chlorine content is more than 0.05 ppm, coloring of the aromatic polycarbonate, particularly when exposed to high temperature for a long time, becomes a problem. Note that chlorine in the present invention means chlorine existing as an acid or salt such as hydrochloric acid, sodium chloride, or potassium chloride, or chlorine in an organic compound such as phenylchloroformate, and a potential difference using an AgNO ₃ solution. It can be quantified by measuring chloride ion by a suitable method.

In the present invention, the amount of xanthone in the diaryl carbonate is 10 ppm or less. As described above, among the diaryl carbonates synthesized by the transesterification method, compounds having a boiling point close to that of the diaryl carbonate are included, and among these, an aromatic polycarbonate is produced using a diaryl carbonate containing xanthone at least 10 ppm. When the obtained aromatic polycarbonate,
It turned out to be blue-green.

The method for producing the diaryl carbonate having a chlorine content of 0.05 ppm or less and xanthone of 10 ppm or less used in the present invention is not particularly limited, and the phosgene method or the transesterification method, that is, various known catalysts for dialkyl carbonate and phenols are used. The diaryl carbonate synthesized by transesterification in the above can be purified and purified by washing or distillation. In order to reduce the amount of chlorine to a very small concentration of 0.05 ppm or less, the transesterification method is more advantageous than the phosgene method. As a catalyst for the transesterification method, there are usually (lead compounds) lead oxides such as PbO, PbO ₂ and Pb ₃ O ₄ ; lead sulfides such as PbS and Pb ₂ S; Pb (OH) ₂ , Pb ₂ O ₂ ( OH) Lead hydroxides such as ₂ ; Na ₂ Pb
Nanamites such as O ₂ , K ₂ PbO ₂ , NaHPbO ₂ , KHPbO ₂ ; Na ₂ Pb
O ₃ , Na ₂ H ₂ PbO ₄ , K ₂ PbO ₃ , K ₂ [Pb (OH) ₆ ], K ₄ PbO ₄ , Ca ₂ PbO
₄ , lead salts such as CaPbO ₃ ; lead carbonates such as PbCO ₃ , 2PbCO ₃ · Pb (OH) ₂ and basic salts thereof; Pb (OCOCH ₃ ) ₂ , P
Lead salts of organic acids such as b (OCOCH ₃ ) ₄ , Pb (OCOCH ₃ ) ₂ · PbO · 3H ₂ O and their carbonates and basic salts; Bu ₄ Pb, Ph ₄ Pb, Bu ₃
PbCl, Ph ₃ PbBr, Ph ₃ Pb (or Ph ₆ Pb ₂ ), Bu ₃ PbOH, Ph ₃ PbO
(Bu indicates a butyl group, Ph indicates a phenyl group); Pb (OCH ₃ ) ₂ , (CH ₃ O) Pb (OPh), Pb (OPh) ₂
Alkoxy lead, aryloxy lead salt; Pb-Na, Pb
-Ca, alloys of lead, such as Pb-Ba, Pb-Sn, Pb-Sb; Hoenn ore, lead minerals such as Sen'aen ore, and hydrates of these lead compounds; (copper compound) CuCl, CuCl ₂ , CuBr, CuBr ₂ , CuI, CuI ₂ , Cu (OAc) ₂ , Cu (ac
ac) ₂ , copper oleate, Bu ₂ Cu, (CH ₃ O) ₂ Cu, AgNO ₃ , AgBr,
Silver picrate, AgC ₆ H ₆ ClO ₄ , Ag (Bourvalen) ₃ NO ₃ , [AuC
{C—C (CH ₃ ) ₃ ] _n [Cu (C ₇ H ₈ ) Cl] _{4 and} other salts and complexes of copper group metals (acac represents an acetylacetone chelate ligand); (complex of alkali metal) Li _{(acac), Lin (C 4} H 9) alkali metal complexes of _2, and the like; (zinc complex) Zn (acac) zinc complex of ₂ and the like; (complex of cadmium) Cd (acac) ₂ and the like complex of cadmium (Compound of iron group metal) Fe (C ₁₀ H ₈ ) (CO) ₅ , Fe (CO) ₅ , Fe (C ₄ H ₆ ) (CO) ₃ , C
o (mesitylene) ₂ (PEt ₂ Ph) ₂ , CoC ₅ F ₆ (CO) ₇ , Ni-π
-C ₅ H ₅ NO, the iron group metal group complexes such as ferrocene; (complexes of zirconium) Zr (acac) _4, complexes of zirconium, such as zirconocene; (Lewis acids _{Compound) AlX 3, TiX 3, TiX} 4, VOX _{3, VX 5, ZnX 2,} FeX 3, SnX 4 ( wherein X
Is a halogen, an acetoxy group, an alkoxy group or an aryloxy group) or a transition metal compound which generates a Lewis acid; (organotin compounds) (CH ₃ ) ₃ SnOCOCH ₃ , (C ₂ H ₅ ) ₃ SnOCOC ₆ H ₅ , Bu ₃ SnOCOCH ₃ ,
Ph ₃ SnOCOCH ₃ , Bu ₂ Sn (OCOCH ₃ ) ₂ , Bu ₂ Sn (OCOC ₁₁ H ₂₃ ) ₂ , P
h ₃ SnOCH ₃ , (C ₂ H ₅ ) ₃ SnOPh, Bu ₂ Sn (OCH ₃ ) ₂ , Bu ₂ Sn (OC ₂ H
₅ ) ₂ , Bu ₂ Sn (OPh) ₂ , Ph ₂ Sn (OCH ₃ ) ₂ , (C ₂ H ₅ ) ₃ SnOH, Ph
Organic tin compounds such as ₃ SnOH, Bu ₂ SnO, (C ₈ H ₁₇ ) ₂ SnO, Bu ₂ SnCl ₂ , BuSnO (OH); (solid catalyst) silica, alumina, titania, silica titania, zinc oxide, zirconium oxide, Gallium oxide, zeolite,
Solid catalysts such as rare earth oxides; those obtained by modifying the surface acid sites of these solid catalysts by a method such as silylation; and the like are used.

These catalysts may or may not be soluble in the reaction solution under the reaction conditions.
Further, these catalysts can be used by being mixed with a compound or a carrier which is inert to the reaction, or supported by these.

Of course, even if these catalyst components are reacted with organic compounds present in the reaction system, for example, aliphatic alcohols, aromatic hydroxy compounds, alkylaryl carbonates, diaryl carbonates, dialkyl carbonates, etc. It may be one that has been subjected to heat treatment with raw materials or products prior to the reaction.

Particularly preferred among these catalysts is Pb
Lead oxides such as O, PbO ₂ , Pb ₃ O ₄ ; Pb (OH) ₂ , Pb ₂ O ₂ (OH) ₂
Lead hydroxides such as PbCO ₃ , 2PbCO ₃ .Pb (OH) ₂ and other lead carbonates and their basic salts; Pb (OCH ₃ ) ₂ , (CH ₃ O) P
b (OPh), Pb (OPh) ₂ and other lead compounds such as alkoxyleads and aryloxyleads, and those lead compounds which have reacted with organic compounds present in the reaction system, or A lead compound which has been heat-treated with a raw material or product prior to the reaction is also preferably used.

Regardless of which catalyst is used, when diaryl carbonate obtained by the reaction is purified by distillation, if the purification requires a long time in the presence of the catalyst, there is a disadvantage that xanthone is generated during the purification. Therefore, especially when a catalyst that is soluble in the reaction solution is used, the diaryl carbonate obtained by the reaction is separated from the catalyst in a short time by a simple distillation or the like, and then a component having a boiling point close to that of the diaryl carbonate such as xanthone. Is preferred.

In the present invention, as a method for producing an aromatic polycarbonate by reacting an aromatic dihydroxy compound and a diaryl carbonate, a known transesterification method,
The solid phase polymerization method described in JP-A-2-180925 can be used, but it is necessary that no catalyst be used. Conventionally known catalysts include hydroxides of alkali metals and alkaline earth metals such as lithium hydroxide, sodium hydroxide, potassium hydroxide and calcium hydroxide; lithium hydroxide, sodium hydroxide, calcium hydroxide Hydroxides of alkali metals and alkaline earth metals such as;
Alkali metal salts, alkaline earth metal salts, and quaternary ammonium salts of hydrides of boron and aluminum, such as lithium aluminum hydroxide, sodium borohydride, and tetramethylammonium borohydride; lithium methoxide, sodium ethoxide, and calcium Alkoxides of alkali metals and alkaline earth metals such as methoxide; lithium phenoxide, sodium phenoxide, magnesium phenoxide, Lio-Ar-OLi, NaO-Ar
Aryloxides of alkali metals and alkaline earth metals such as -ONa (Ar is an aryl group); organic acid salts of alkali metals and alkaline earth metals such as lithium acetate, calcium acetate and sodium benzoate; zinc oxide, zinc acetate, Zinc compounds such as zinc phenoxide; boron compounds such as boron oxide, boric acid, sodium borate, trimethyl borate, tributyl borate, triphenyl borate; silicon oxide, sodium silicate, tetraalkyl silicon, tetraaryl Silicon compounds such as silicon and diphenyl-ethyl-ethoxysilicon; germanium compounds such as germanium oxide, germanium tetrachloride, germanium ethoxide, and germanium phenoxide; tin oxide, dialkyltin oxide, diaryltin oxide, dia Tin compounds such as tin compounds and organotin compounds combined with alkoxy or aryloxy groups such as killtin carboxylate, tin acetate and ethyltin tributoxide; lead oxide, lead acetate, lead carbonate, basic lead carbonate, lead And lead compounds such as alkoxides or aryloxides of organic lead; onium compounds such as quaternary ammonium salts, quaternary phosphonium salts and quaternary arsonium salts; antimony compounds such as antimony oxide and antimony acetate; acetic acid Manganese compounds such as manganese, manganese carbonate, manganese borate;
Titanium compounds such as titanium oxide, titanium alkoxide or aryl oxide; zirconium compounds such as zirconium acetate, zirconium oxide, zirconium alkoxide or aryl oxide, and zirconium acetylacetone; and combinations thereof are also used. The use of any of these catalysts is not preferable because it causes a problem of coloring of the obtained aromatic polycarbonate.

(Effect of the Invention) In the present invention, in producing an aromatic polycarbonate from an aromatic dihydroxy compound and a diaryl carbonate, the amount of chlorine and the amount of xanthone in the diaryl carbonate are set to a specific value or less, and by polymerization without a catalyst, A high-quality aromatic polycarbonate without coloring can be obtained.

(Examples) Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

The molecular weight is a number average molecular weight (hereinafter abbreviated as Mn) measured by gel permeation chromatography (GPC).

The color was measured by a CIELAB method at a specimen thickness of 3.0 cm, and the yellowness was indicated by a b ^* value. Colors other than yellow were visually observed.

The chlorine content was determined by a potentiometric titration method using an AgNO ₃ solution.

The xanthone content was determined by liquid chromatography.

In addition, injection molding was performed using a modern machinery MJEC-injection molding machine at a resin temperature of 300 ° C and a mold of 90 ° C.
No. dumbbell was made.

Example 1 1) Production of methylphenyl carbonate 1.8 kg of dimethyl carbonate, 1.88 kg of phenol, PbO
30 g was charged into a pressurized reactor equipped with a stirrer, a liquid inlet reaching below the liquid level, a gas outlet and a gas condenser, and dimethyl carbonate was supplied at 7 kg / Hr from the liquid inlet to produce a by-product. While extracting methanol and dimethyl carbonate at 7 kg / Hr from a gas outlet through a gas condenser, 13 kg / cm ²
G, reacted at 214 ° C. for 2 hours. After 2 hours, methylphenyl carbonate was obtained in a yield of 33% based on the charged phenol. From this reaction solution, 0.9 kg of methylphenyl carbonate was obtained by distillation.

2) Production of diphenyl carbonate Pretreatment of the catalyst was performed by heating 20 g of PbO and 100 g of methylphenyl carbonate to 180 ° C. for 1 hour under a small amount of nitrogen stream. Subsequently, unreacted methylphenyl carbonate and most of the generated diphenyl carbonate were distilled off at 150 ° C. under a reduced pressure of 0.5 mmHg to obtain 25 g of a pale yellow solid. To this, 760 g (50 mol) of the methylphenyl carbonate was added, and the whole amount was stirred.
The mixture was transferred to two reactors provided with a reflux condenser, a gas inlet reaching below the liquid level of the vacuum device, and a thermometer. Dry nitrogen
The reaction was carried out by immersion in an oil bath at 195 ° C. with stirring at 0.8 / min. Water at 90 ° C. was flowed through the jacket of the reflux condenser, and while methanol produced as a by-product was distilled off, methylphenyl carbonate and diphenyl carbonate were refluxed and returned to the reactor to carry out the reaction. After 3 hours, diphenyl carbonate was obtained in 90% yield.

Unreacted methylphenyl carbonate and diphenyl carbonate are distilled off from the reaction solution under a reduced pressure of 10 Torr,
Separated from catalyst. The distilled reaction solution contained 100 ppm of xanthone based on diphenyl carbonate.
Distilled reaction solution was filled with Dixon 6φ at a height of 3m,
Purification was carried out with a reflux ratio of 2.6 in a rectification column having a diameter of 3 inches to obtain diphenyl carbonate having a xanthone content of 1 ppm. The chlorine content in this diphenyl carbonate was not more than the lower detection limit of 0.03 ppm.

3) Production of aromatic polycarbonate 140 g of said diphenyl carbonate, bisphenol A137
g was charged into a reactor equipped with a stirrer, a gas inlet, and a gas suction port, and after repeating vacuum degassing and dry nitrogen introduction several times, the temperature was raised to 180 to 190 ° C., and the contents were melted. Degassing and dry nitrogen introduction were performed. Then, the temperature was raised to 230 ° C,
Dry nitrogen was introduced at 50 Nl / Hr under stirring to distill off the phenol produced. After about 50 minutes, the temperature rises to 260 ° C,
The reaction system was polymerized at 1 mmHg for 1 hour under reduced pressure to distill phenol and diphenyl carbonate. As a result, an aromatic polycarbonate having Mn = 7000 was obtained.

The obtained polycarbonate was pulverized and injection-molded to produce a dumbbell. As a result, b ^* was 3.9, and no coloring was observed.

Example 2 134 g of diphenyl carbonate and 130 g of bisphenol A obtained in Example 1 were charged into a reactor similar to that of Example 1, and the mixture was degassed under reduced pressure and dried nitrogen was introduced several times.
After elevating the temperature to 190 ° C. to melt the contents, deaeration under reduced pressure and introduction of dry nitrogen were performed. Next, the temperature was raised to 230 ° C., and dry nitrogen was introduced at 50 Nl / Hr with stirring to distill off the phenol produced. After about 50 minutes, the reaction system was evacuated to 2 to 5 mmH
The phenol and diphenyl carbonate were distilled off by stirring with g for 15 minutes. As a result, Mn =
4000 aromatic polycarbonates were obtained. This was taken out of the reactor, ground, and then crystallized by immersion in 500 ml of acetone for 1 hour. After drying, the reactor was again charged and subjected to solid-state polymerization at 210 ° C. for 7 hours while introducing a small amount of dry nitrogen under a reduced pressure of 2 to 5 mmHg.
An aromatic polycarbonate having n = 11,000 was obtained.

When a dumbbell was prepared by injection molding the obtained polycarbonate, b ^* was 3.8 and no coloring was observed.

Examples 3 and 4, Comparative Examples 1 and 2 Diphenyl carbonate was produced in the same manner as in Example 1. However, the reflux ratio in the rectification columns of Examples 3 and 4 and Comparative Examples 1 and 2, respectively, was purified as 2.1, 1.8, 1.6, and 1.2, and the xanthone content was 4 ppm, 8 ppm, 15 ppm, and 30 ppm.
Of diphenyl carbonate was obtained. This was polymerized in the same manner as in Example 2 and injection molded, and then the color of the dumbbell was evaluated. The results are summarized in Table 1.

Comparative Example 3 Diphenyl carbonate having a chlorine content of 5 ppm (manufactured by Bayer)
Was washed with hot water of pH 7 at 80 ° C. and distilled under reduced pressure to obtain diphenyl carbonate having a chlorine content of 0.09 ppm. Using this diphenyl carbonate, an aromatic polycarbonate having Mn = 9000 was obtained in the same manner as in Example 2, and this was injection molded to produce a dumbbell. The b ^* of the dumbbell was 4.3.

Comparative Example 4 Polymerization was carried out in the same manner as in Example 1 using the diphenyl carbonate obtained in Example 1 to obtain an aromatic polycarbonate. However, as a polymerization catalyst, 9 mg of boric acid and 91% of a 15% aqueous solution of tetramethylammonium hydroxide were used.
g and 1.3 mg of sodium bicarbonate were added. B ^{* of} dumbbell obtained by injection molding the obtained aromatic polycarbonate
Was 4.5.

Claims (1)

(57) [Claims] 1. A method for producing an aromatic polycarbonate by reacting an aromatic dihydroxy compound with a diaryl carbonate, wherein a polymerization catalyst is not used, the chlorine content is 0.05 ppm or less, and the xanthone content is 10 ppm or less. A process for producing an aromatic polycarbonate, comprising using a diaryl carbonate which is