JPH0193560A - Production of diaryl carbonate - Google Patents

Abstract

PURPOSE:To obtain the objective compound in high yield and selectivity, by using a lead catalyst in the production of diaryl carbonate by the disproportionation of alkyl aryl carbonate into diaryl carbonate and dialkyl carbonate. CONSTITUTION:A diaryl carbonate can be produced by the disproportionation of an alkyl aryl carbonate (preferably having 1-4C lower aliphatic group as the alkyl group and phenyl group or 7-15C substituted phenyl group as the aryl group) into a diaryl carbonate and a dialkyl carbonate in the presence of a lead catalyst (preferably metallic lead or neutral or basic lead compound, especially powdery lead, granular or powder alloy of lead and sodium, various lead oxides, lead hydroxides, lead carbonate, basic lead carbonates, etc.), usually at 50-400 deg.C, preferably at 80-300 deg.C. The objective carbonate is produced in high yield and selectivity without problems such as corrosion of the apparatus caused by the use of a Lewis acid.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for producing diaryl carbonate.

Specifically, Ao et al. relates to a method for producing diaryl carbonate by disproportionation reaction of alkylaryl carbonate.

(Prior Art) It is already known to obtain diphenyl carbonate by disproportionating alkylphenyl carbonate (% Publication No. 58-48557). However, this method uses a catalyst selected from Lewis acids and transition metal compounds capable of producing Lewis acids. J4 Physically A
DC4, TiX3. UX4゜VOXB, VX, ,
ZnX, , FeX, , SnX, (X is a halogen, an acetoxy group, an alkoxy group, or an aryloxy group) are listed. Such Lewis acids cause serious corrosion of equipment and are problematic for industrial use.

Furthermore, a method using a mixture of a Lewis acid and a protonic acid as a catalyst has also been proposed (%KOKAI Publication No. 1016/1983), but this method uses a protonic acid in addition to a Lewis acid. What is the problem with 1g meals?

Not only does it become more time consuming, but it is also difficult to separate and recover the catalyst.

(Problems to be Solved by the Invention) The present invention provides an excellent method for obtaining diaryl carbonate with high yield and high selectivity without the problems of the conventional methods. It was made for the purpose of:

(Means for Solving the Problems) The present inventors have conducted intensive research to solve these problems, and as a result, have discovered an excellent catalyst.

The present invention has now been completed.

That is, one aspect of the present invention provides a method for producing diaryl carbonate, which comprises disproportionating alkylaryl carbonate into diaryl carbonate and dialkyl carbonate in the presence of a lead catalyst.

The method of the present invention is represented by the following general formula (I).

2R-0-C-0-Ar2Ar-0-C-0-Ar
+R-0-C-0-R...CI) (here, R
represents an alkyl group such as an aliphatic group, a ring group, or an aromatic aliphatic group, and At represents an aryl group which is an aromatic group. This is the compound shown on the left side of . R is 1, for example, methyl, ethyl, furovir,
Butyl, pentyl, hexyl.

Aliphatic groups including each isomer such as heptyl, octyl, nonyl; cyclopropyl, cyclobutyl.

Alicyclic groups such as cyclopentyl, cyclohexyl, methylcyclobutyl, cyclohexylmethyl: penzyl, 7
An aromatic aliphatic group such as enethyl is preferable, and Ar is an unsubstituted aromatic group such as phenyl, naphthyl, pyridyl; a substituted aromatic group represented by the following formula (where R/ is a lower alkyl group, alkoxy group.

Acyl group, halogen, aryloxy group, aromatic group.

It represents a substituent such as a nitro group, a cyano group, an aromatic aliphatic group, t is an integer of 1 to 5, and mi is an integer of i1 to 7.

n#'i indicates an integer from 1 to 4, where t, m, and n are each 1
In the case of the above integers, it is preferable that H/ may be the same or different.

Mayu, in R, one or more hydrogens are halogen.

Those substituted with substituents such as lower alkoxy groups and cyano groups can also be used.

Particularly preferred alkylaryl carbonates include:
Alkyl groups are methyl, ethyl, and propyl.

In the case of a lower I aliphatic group having 1 to 4 carbon atoms of butyl,
In addition, as an aryl group, a phenyl group has 1 carbon number.
-9 substituents 1 e.g. methyl, dimethyl, ethyl, t
This is the case of a substituted phenyl group having 7 to 15 carbon atoms and having a substituent such as -butyl and 2-phenyl-2-methylethyl.

The lead catalyst used in the invention may be any lead or a compound containing lead, but basic or neutral lead compounds are preferred. One example of such a lead compound is:

Lead oxides such as pbo, pbo, , Pb3O4; PbS, Pb, S, .

Lead sulfides such as pbs; Pb(OH), , Pb
1O, (O)I), .

Pb, (PbO, (OH)! ), Pb, 0(OH
), lead hydroxides; Na1PbO,, 1F'bO
1. Namarites such as NaHPbO, KHPbOl, Na, PbO, NatHlPbOa,
pbo, , KJPb(OH)a).

K4PbO, Ca, PbO, CaPbO, and other lead salts; PbC0,.

2 Lead carbonates and their basic salts such as PbCO, Pb(OH); Pb(OCOCHI)! , Pb(O
COCHs%, Pb(OCOCR,).

・Lead salts of organic acids such as Pb0 and 3H20, and their carbonates and basic salts; Bu, Pb, Ph, Pb, B
u, PbC4.

Ph5PbBr, PhxPb (or ph, Pb,
), Bu, PbOH.

Organic lead compound #A with phtpbo (Bu is a butyl group.

ph indicates a phenyl group), "Pb-Na, P
b-Ca.

Lead alloys such as Pb-Ba, Pb-Sn, and Pb-Sb; lead ores such as boenite and sennenite! t2! Type 1.

and hydrates of these compounds are preferably used. Of course, these lead compounds are present in the reaction system as organic compounds 1, such as alkylaryl carbonates and diaryl carbonates.

It may be a product reacted with a dialkyl carbonate or a hydrolysis product of these compounds (alcohol, aromatic compound, droxy compound, etc.).

Materials that have been heat-treated with raw materials or products prior to reaction6
You may

Among these, a particularly preferred catalyst is powdered lead.

Fine particles are powdered lead) IJium alloys, various lead oxides, lead hydroxides, lead carbonates and basic lead carbonates, namalites and leadates, lead acetate and basic acetic acid. such as lead.

Such catalysts are made of lead compounds.

One type may be used, or a mixture of 281 or more types may be used.

Mayu, there is no particular limit on the amount of lead catalyst used, but it is usually 0.000 per alkylaryl carbonate.
It is used in a range of 0.01 to 100 times the mole, preferably 0.001 to 2 times the mole.

The catalyst of the present invention is excellent in providing diaryl carbonate in high yield and high selectivity.Furthermore, these lead and lead compounds are neither Lewis acids nor transition metals capable of producing Lewis acids. Since it is not a chemical compound, it is also characterized by the fact that there are no problems such as corrosion of equipment caused by the use of Lewis acids.

Since the reaction of the present invention is an equilibrium reaction as shown in formula (I), at least part of the diaryl carbonate product is removed from the reaction system. K allows one reaction to proceed much more smoothly.

Since the reaction of the present invention is usually carried out in a liquid phase or a gas phase, it is preferable to proceed with the reaction while distilling off low-boiling components of the product. The boiling points of raw materials and products are 1
Generally, since diaryl carbonate) > 1 alkylaryl carbonate) > dialkyl carbonate, or dialkyl carbonate) alkylaryl carbonate > diaryl carbonate, a part of the product can be easily distilled off. Dialkyl carbonates whose alkyl groups are lower aliphatic groups such as methyl, ethyl, propyl, and butyl have low boiling points and can be easily distilled off from the reaction system. In this sense, alkylaryl carbonates having lower aliphatic groups are preferably used.

Nitrogen to effectively distill off low-boiling components.

Inert gases such as argon, helium, carbon dioxide, and lower hydrocarbon gases are introduced into the reaction system.

Methods of entraining these gases, methods of performing under reduced pressure,
and nine methods using these in combination are preferably used. In addition, in the case of a seed reactor, it is also a preferable method to carry out effective stirring in order to increase the gas-liquid interface area and promote fc1 surface renewal. It is also a preferable method to use a device with a large liquid interface area.

The reaction of the present invention is usually carried out at 50 to 400C, preferably at 8C.
It is carried out in the range of 0 to 300C. Also.

The reaction time ranges from several minutes to several tens of hours.

The reaction pressure may be reduced, normal pressure, or increased pressure.

The method of the present invention can be carried out without a solvent or with a solvent. When using a solvent.

Co-removal of the low-boiling products with a portion of the solvent is also a preferred method. Examples of such solvents include pentane, hexane, heptane, and octane.

Aliphatic hydrocarbons such as nonane, decane, undecane, tridecane; benzene, toluene, xylene.

Aromatic raw carbons such as ethylbenzene and styrene; arsenic;
Alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; methane chloride and methylene chloride.

Halogenated hydrocarbons such as chloroform, carbon tetrachloride, dichloroethane, chlorobenzene, and dichlorobenzene; Nitriles such as niacetonitrile, propionitrile, and benzonitrile; acetone;

Ketones such as methyl ethyl ketone and acetophenone, diethyl ether, and tetrahydro-7ran.

Ethers such as dioxane and diphenyl ether are preferably used.

Furthermore, the method of the present invention can be carried out in either a single-batch method or a continuous method.

(Examples) Next, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples.

Example 1 A catalyst was pretreated by heating 10r of PbO2r, methylphenyl carbonate for 1 hour at 180C under a small stream of nitrogen. Next.

By distilling off unreacted methylphenyl carbonate and most of the formed diphenyl carbonate under reduced pressure of 0.511 HH at 150C.

Obtained 2.5v of pale yellow solid. ``To this, add methylphenyl carbonate) 76 F (0.5 mol)''!!-
The entire amount was transferred to a 200 m 14 flask equipped with a stirrer, a reflux condenser, a gas inlet reaching below the liquid level, and a thermometer. The reaction was carried out by immersion in a 195 C oil bath with stirring while introducing dry nitrogen at 80-7 minutes. Water at 90C is passed through the jacket of the reflux cooler, and by-product methanol is distilled off. Methylphenyl carbonate and the generated diphenyl carbonate are the result of the reaction by being refluxed and returned to the reactor. Table 1
Shown below.

Table 1 Examples 2 to 11 The reaction from methylphenyl carbonate (76r) to diphenyl carbonate was carried out in the same manner as in Example 1, except that a lead compound or lead was used as the PbOO substitute. The reaction results after 2 hours are shown in Table 2. In addition,
In these examples, the catalyst was used at 5 mmol or 5 to -atomi as lead. 7tP used in Example 3
The b-Na alloy is pb'1? This includes the amount of Ofi. In addition, in Examples 2.3°7.8 and 9, the reaction was carried out directly without pretreatment of the catalyst.

Table 2 Examples 12 to 17 The reaction was carried out in exactly the same manner as in Example 1, except that various alkylaryl carbonates were used in place of methylphenyl carbonate, and the reaction results after 2 hours are shown in Table 3.

Table 3 In Examples 12 and 13, the reaction temperature was 210C, and oil at 130C was circulated in the reflux condenser.

(Effect of the invention) According to the invention, by using a lead catalyst.

Diaryl carbonate can be produced with high yield and high selectivity, and problems such as corrosion of equipment caused by the use of catalysts such as Lewis acids are eliminated.

Claims (4)

[Claims] (1) A method for producing diaryl carbonate, which comprises averaging alkylaryl carbonate into diaryl carbonate and dialkyl carbonate in the presence of a lead catalyst. (2) The method according to claim 1, wherein the lead catalyst is lead and a neutral or basic lead compound. (3) The method according to claim 1 or 2, wherein the alkyl group is a lower aliphatic group having 1 to 4 carbon atoms. (4) Claims 1 to 5, wherein the aryl group is a phenyl group or a substituted phenyl group having 7 to 15 carbon atoms.
The method described in any of the paragraphs.