JP2009242302A - Method for producing alkylaryl carbonate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an alkylaryl carbonate wherein the transesterification of an aromatic hydroxy compound and a dialkyl carbonate is efficiently carried out. <P>SOLUTION: The method for producing an alkylaryl carbonate by causing an aromatic hydroxy compound and a dialkyl carbonate to react with each other by a gas phase reaction, is characterized by using as a catalyst, a metal oxide at least containing iron or cerium as metal. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

Carbonate is a useful compound for polycarbonate raw materials not using phosgene, lithium battery electrolytes, gasoline additives for improving octane number, alkylating agents in various reactions, carbonylating agents, and the like.
As a conventional method for producing a carbonate ester, first, a method for producing a carbonate ester by reacting phosgene with an alcohol such as methanol, ethanol or phenol using a carbonylating agent as a carbonylating agent is known and produced on an industrial scale. Has been. However, since this method uses phosgene, which is extremely toxic and corrosive, care must be taken in handling such as transportation and storage. For maintenance and management of manufacturing facilities, waste disposal, ensuring worker safety, etc. Was costly. Therefore, a method for producing a carbonate ester without using phosgene is desired, and various methods have been studied. Known methods for producing carbonate esters without using phosgene include oxidative carbonylation, in which carbon monoxide is used as a carbonylating agent to react with alcohol and oxygen, a method in which oxirane and carbon dioxide are reacted, and a method in which urea and alcohol are reacted. (Non-Patent Document 1).

As a method for producing a diaryl carbonate, a method for producing a target diaryl carbonate by transesterifying a dialkyl carbonate, such as dimethyl carbonate, which is generally easily available and an aryl compound such as phenols, is known. In general, it is known that the reaction proceeds by a combination of the following reactions.
1) A transalkylation reaction between a dialkyl carbonate and an aromatic hydroxy compound is performed to produce an alkyl aryl carbonate.
2) The alkylaryl carbonate and the aromatic hydroxy compound are transesterified to produce a diaryl carbonate.
3) Diaryl carbonate and dialkyl carbonate are produced by disproportionation of alkylaryl carbonate, and purified and separated.
Both of the above reactions are equilibrium reactions. In particular, since the equilibrium state of the reaction described in 1) is biased toward the raw material side (dialkyl carbonate side), in order to improve the overall reactivity of the diaryl carbonate production reaction, It is important to shift the equilibrium state in the reaction described in 1) to the product side (alkyl aryl carbonate side).

Up to now, as a method for moving the equilibrium state in the reaction described in 1) above to the product side, the reaction described in 1) is performed in a gas phase state, using a catalyst in which titanium oxide is supported on a silica support, A method has been disclosed in which the equilibrium is biased toward the product side (alkyl aryl carbonate side) by carrying out the reaction to advance the reaction (Patent Document 1, Non-Patent Document 2). However, in the above reaction, since the reaction is performed at a high temperature, the reaction rate of the side reaction is increased, and there is a difficulty in that the selectivity of the alkylaryl carbonate tends to be lowered.
Ullmann's Encyclopedia Of Industrial Chemistry, 6th Edition, Vol. 6 P427-455 Catalysis Letters, 59, 83-89 (1999) WO2001-00560

  This invention makes it a subject to provide the manufacturing method of the alkyl aryl carbonate which performs efficiently the transesterification reaction of an aromatic hydroxy compound and a dialkyl carbonate. Furthermore, it is an object to provide a method for producing a dialkyl carbonate using the alkylaryl carbonate produced above and a method for producing a polycarbonate using the dialkyl carbonate.

  As a result of intensive studies to solve the above problems, the inventors of the present invention contain at least iron or cerium as a metal when the transesterification reaction of an aromatic hydroxy compound and a dialkyl carbonate is performed in a gas phase. It has been found that by using a metal oxide as a catalyst, an alkylaryl carbonate is produced with high selectivity while maintaining a sufficient reaction rate, and the present invention has been completed.

That is, the present invention
(1) In an alkylaryl carbonate production method for producing an alkylaryl carbonate by reacting an aromatic hydroxy compound and a dialkyl carbonate in a gas phase, an alkyl characterized by using a metal oxide containing at least iron or cerium as a catalyst. Production method of aryl carbonate,
(2) The method for producing an alkylaryl carbonate according to the above (1), wherein the metal oxide is iron (III) oxide,
(3) The method for producing an alkylaryl carbonate according to the above (1), wherein the metal oxide is cerium (IV) oxide,
(4) A method for producing a diaryl carbonate, comprising transesterifying the alkylaryl carbonate produced by the method according to (1) to (3) above,
(5) The method for producing a diaryl carbonate according to (4), wherein the diaryl carbonate is diphenyl carbonate,
(6) A method for producing a polycarbonate, comprising melt-polymerizing diphenyl carbonate and bisphenol A produced by the method described in (5) above,
It is.

  INDUSTRIAL APPLICABILITY According to the present invention, there is provided a method with high selectivity while maintaining a sufficient reaction rate in a method for producing an alkylaryl carbonate by transesterification of an aromatic hydroxy compound and a dialkyl carbonate. In addition, a method for producing diaryl carbonate using the alkylaryl carbonate thus produced as a raw material, and further using this to produce a polycarbonate efficiently without using harmful components has been provided.

The method for producing an alkylaryl carbonate of the present invention is characterized in that an aromatic hydroxy compound and a dialkyl carbonate are reacted by a gas phase reaction using a metal oxide containing at least iron or cerium as a metal as a catalyst. To do.
(material)
Examples of the aromatic hydroxy compound used in the method of the present invention include an aromatic monohydroxy compound, an aromatic dihydroxy compound, and an aromatic trihydroxy compound depending on the number of hydroxy groups substituted on the aromatic ring. Group monohydroxy compounds are preferred. Specifically, for example, phenol, cresol, xylenol, alkylphenol having an alkyl group having 1 to 12 carbon atoms such as 2- (or 3-, 4-) ethylphenol, 2- (or 3-, 4-) Alkoxyphenol having an alkoxy group having 1 to 12 carbon atoms such as methoxyphenol and 2- (or 3-, 4-) ethoxyphenol, and nitro having a nitro group such as 2- (or 3-, 4-) nitrophenol Halogenophenol having a halogen atom such as phenol, 2- (or 3-, 4-) fluorophenol, 2- (or 3-, 4-) chlorophenol, naphthol such as α-naphthol, β-naphthol, etc. Among these, phenol is particularly preferable.

  In addition, as the dialkyl carbonate, a carbonate having a linear alkyl group having 1 to 12 carbon atoms and a branched alkyl group such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, diisopropyl carbonate, dibutyl carbonate, diisobutyl carbonate, dihexyl carbonate, dioctyl carbonate, etc. Is good. Moreover, the carbonate which has two different alkyl groups like methyl ethyl carbonate may be sufficient, and cyclic carbonates, such as ethylene carbonate and propylene carbonate, may be sufficient. Of these, dimethyl carbonate is particularly preferred.

(Metal oxide)
The metal oxide used as a catalyst in the method of the present invention contains at least iron or cerium. Specifically, when iron is contained, it is preferably contained in the metal oxide as iron (III) oxide and when cerium is contained, as cerium (IV) oxide.
For these metal oxides, a conventional method for preparing a metal oxide catalyst can be used. Specifically, for example, a powder obtained by drying an aqueous solution (or aqueous dispersion) containing iron or a cerium compound is heat-treated, and then molded and fired (for example, Kodansha Scientific) Tifik Catalyst Preparation Chemistry, Kodansha (1980), p214-215) is mentioned, but it is not particularly limited to these.

Specific examples of iron or cerium compounds include iron or cerium halides, sulfates, nitrates, ammonium salts, oxides, carboxylates, ammonium carboxylates, ammonium halides, hydrogen acids, acetylacetonates. And alkoxides.
In addition to the above-mentioned metal oxide, a substance generally known to improve the physical properties of the catalyst such as thermal stability and strength of the catalyst is added to the catalyst used in the method for producing an alkylaryl carbonate of the present invention. May be used. It is also preferable to add a binder component or the like in order to mold the catalyst. Furthermore, the above metal oxide can be supported on a carrier such as alumina which is generally used.

  In addition to the above iron and cerium, the metal oxide of the present invention may further contain an alkali metal such as sodium or magnesium, an alkaline earth metal, a metal such as titanium, zirconium or tungsten.

(Transesterification reaction)
The transesterification performed in the method for producing an alkylaryl carbonate of the present invention is performed in the gas phase. The reaction conditions and method can be appropriately selected from commonly used methods according to the reaction raw materials, catalysts, equipment, etc., but the temperature at which both the aromatic hydroxy compound and dialkyl carbonate as raw materials are in a gaseous state, It must be a condition. Specifically, the reaction is preferably performed at a temperature of 320 to 600 ° C. The amount of the metal composite oxide is preferably in a range where the space velocity (SV) is 1000 to 10,000.

In the transesterification reaction of the present invention, since the liquid is not stabilized for a while after the start of the liquid flow, it is preferable to start the reaction after passing the reaction liquid to some extent. The liquid passing time for stabilization is preferably 8 hours or longer after the start of liquid passing, and more preferably 12 hours or longer.
The alkylaryl carbonate thus produced can be appropriately purified and obtained by a commonly used method known per se.

(Method for producing diaryl carbonate)
The alkylaryl carbonate obtained by the method for producing an alkylaryl carbonate of the present invention is subjected to a disproportionation reaction in the liquid phase in the presence of an acidic catalyst, and the resulting dialkyl carbonate is removed to produce a diaryl carbonate. A known catalyst can be used as the acidic catalyst.
The disproportionation reaction can be carried out at a known temperature and pressure, but it is preferable to carry out the reaction under reaction conditions of 150 to 250 ° C. and 0.01 to 2.0 Pa. Although there is no restriction | limiting in the removal method of the dialkyl carbonate to produce | generate, The method of advancing reaction, removing a product with a reactive distillation apparatus is preferable. If necessary, purification such as removal of residual catalyst may be further performed.

(Polycarbonate production method)
As the dialkyl carbonate obtained as described above, with respect to diphenyl carbonate, bisphenol A can be reacted in the presence of an alkali catalyst to produce a polycarbonate. Examples of the method for producing this polycarbonate include publicly known and commonly used methods. For example, the method described in Plastic Materials Course, Polycarbonate Resin, Second Edition, p62-65, Nikkan Kogyo Shimbun (1976), etc. Used. In addition, as alkali catalysts, alkali metal hydroxides such as sodium hydroxide, various salts such as carbonates such as sodium carbonate and cesium carbonate, ammonium hydroxide compounds such as tetramethylammonium hydroxide, etc. are used. can do.

  The reaction temperature is preferably raised stepwise as the polymerization proceeds in the range of 120 to 300 ° C, and the temperature of the final polymerization step is preferably 250 ° C to 300 ° C. The reaction pressure is preferably increased stepwise as the polymerization proceeds, and the pressure reduction in the final polymerization step is preferably 1 kPa or less.

EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited to a following example, unless the summary is exceeded.
Example 1
(1) Catalyst preparation 265.4 g of iron nitrate (III) aqueous solution (38.74 g in terms of iron (III) oxide) was added to an aqueous ammonia solution (manufactured by Wako Pure Chemicals, special grade reagent) at 5 ° C to Neutralization treatment was performed at a low temperature of 10 ° C. The produced hydrogel was filtered by suction and washed with pure water to obtain an iron hydrogel cake. The obtained hydrogel cake was dispersed in pure water, and after adding 22.50 g of 50 wt% ammonium metatungstate aqueous solution (manufactured by Nippon Inorganic Chemical Industry Co., Ltd.), the mixture was stirred and mixed (7500 rpm, 15 minutes) with a disperser. The resulting slurry solution was concentrated and dried overnight at 250 ° C. in a constant temperature dryer and subjected to salt decomposition.

  Next, water was added to the obtained solid, and pulverized and mixed for about 30 minutes with an automatic mortar until it became creamy. This creamy slurry was transferred to a Teflon (registered trademark) vat and dried at 150 ° C. overnight in a circulation dryer. The obtained solid was molded into a disk shape of about 2 cmφ with a press molding machine, and then calcined in a muffle furnace at 500 ° C. for 3 hours to obtain a catalyst. All the above operations were performed in air. Table 1 shows the molar composition of metal components in the catalyst calculated from the charged amount.

(2) Reaction and analysis The catalyst obtained by the above method (1) was pulverized and granulated to 10 to 20 mesh for evaluation, and filled into a SUS reaction tube having an inner diameter of 10 mm. Thereafter, a ceramic heater was attached around the reactor and heated to 400 ° C. over 1 hour while flowing nitrogen gas at 0.5 L / hr. Next, a dimethyl carbonate-phenol mixed solution (dimethyl carbonate: phenol (molar ratio) = 10: 1) was fed to the reaction tube at 12 ml / hr for 48 hours using a plunger pump.

  The obtained reaction product was collected every hour and analyzed by gas chromatography (Shimadzu GC-2014 column: TC-5 manufactured by GLscience, column temperature: 50 ° C. to 300 ° C., inlet temperature: 300 ° C.). As a result, the reaction was stabilized 8 hours after the start of liquid flow, and the reaction liquid was collected and analyzed. The yield of methyl phenyl carbonate is 32.2%, the selectivity is 96.7%, and the yield of methyl phenyl carbonate is 34.5% in the collected liquid of 48 hours. The selectivity was 98.5%. The results are shown in Table 1.

Example 2
In the catalyst preparation of Example 1, 111.7 g of cerium (IV) nitrate aqueous solution (44.06 g in terms of cerium (IV) oxide) was used instead of the iron (III) nitrate aqueous solution, and a 50 wt% ammonium metatungstate aqueous solution. The catalyst was prepared in the same manner as in Example 1 except that the amount of addition was 11.87 g.

  In the reaction and analysis, using the same apparatus as in Example 1, the reaction was carried out under the conditions of a nitrogen gas flow rate of 0.99 L / hr, a reaction temperature of 320 ° C., and GHSV 3000 hr-1, and the analysis was performed in the same manner as in Example 1. went. As a result, the yield of methyl carbonate was 14.5% and the selectivity was 46.6% in the collected liquid having a flow time of 8 hours. The results are shown in Table 1.

Comparative Example 1
In the catalyst preparation of Example 1, instead of the iron (III) nitrate aqueous solution, 100 ml of titanium tetrachloride aqueous solution (38.74 g in titania conversion) was used, and a 50 wt% aqueous solution of ammonium metatungstate (manufactured by Nippon Inorganic Chemical Industry). ) Was added in the same manner as in Example 1 except that the amount added was 22.50 g.
The reaction and analysis were performed in the same manner as in Example 1. The yield of methyl phenyl carbonate is 2.0%, the selectivity is 62.5%, and the yield of methyl phenyl carbonate is 1.3% in the collected liquid for 30 hours. The selectivity was 78.4%. The results are shown in Table 1.

Comparative Example 2
Tetrabutoxytitanium (Tokyo Kasei) 7.11 g of toluene solution was impregnated with 10 g of silica gel (Fuji Silysia), concentrated to dryness, dried (110 ° C., 12 hours), and calcined (500 ° C., 4 hours). Catalyst composition: 10 weight percent titanium with respect to silica gel).
Using this supported catalyst, the reaction and analysis were conducted in the same manner as in Example 1. As a result, the yield of methyl phenyl carbonate was 25.6% and the selectivity was 96.9% in the collected liquid having a flow time of 8 hours. The results are shown in Table 1.

Example 3 Production Method of Diphenyl Carbonate A 1 L stainless steel autoclave equipped with a 30 cm high packed tower was charged with 380 g (2.5 mol) of methyl phenyl carbonate obtained in Example 1 and 6.3 g of dibutyl tin oxide (0 0.025 mol), and reactive distillation was performed at 180 ° C. and 9.5 atm in a nitrogen atmosphere. The reaction was carried out until dimethyl carbonate extracted from the upper part of the packed column was not distilled.
From the bottom of the tower, 267 g of a bottom liquid containing diphenyl carbonate as a main component was obtained. This was further distilled under reduced pressure at 180 ° C. and 20 Torr in a nitrogen atmosphere to obtain 242 g of high-purity diphenyl carbonate from the top.

Example 4 Production Method of Polycarbonate 220 g (1.03 mol) of diphenyl carbonate obtained in Example 3, 226 g (1.00 mol) of bisphenol A (manufactured by Mitsubishi Chemical Corporation), and an aqueous solution (0.005 mol) of cesium carbonate as a catalyst / L) was added at 0.1 ml, charged into a polymerization apparatus capable of stirring at high viscosity, purged with nitrogen, and then heated and melted to 210 ° C. After reducing the pressure to 100 Torr and reacting for 60 minutes while removing the distilled phenol, 240 ° C, 15 Torr, 260 ° C, 0.5 Torr, 270 ° C, 0.5 Torr and the degree of pressure reduction and the temperature stepwise. While raising, each was reacted for 60 minutes to obtain a transparent polycarbonate. The viscosity average molecular weight of the obtained polycarbonate was Mv = 21000.

Claims (6)

  In an alkylaryl carbonate production method for producing an alkylaryl carbonate by reacting an aromatic hydroxy compound and a dialkyl carbonate in a gas phase, a metal oxide containing at least iron or cerium is used as a catalyst. Manufacturing method.   The method for producing an alkylaryl carbonate according to claim 1, wherein the metal oxide is iron (III) oxide.   The process for producing an alkylaryl carbonate according to claim 1, wherein the metal oxide is cerium (IV) oxide.   A process for producing a diaryl carbonate, comprising transesterifying the alkylaryl carbonate produced by the method according to claim 1.   The method for producing a diaryl carbonate according to claim 4, wherein the diaryl carbonate is diphenyl carbonate.   A method for producing a polycarbonate, comprising melt-polymerizing diphenyl carbonate and bisphenol A produced by the method according to claim 5.