JPH04193848A - Production of aromatic carboxylic acid ester - Google Patents

Abstract

PURPOSE:To obtain the subject compound in high yield and efficiency under relatively mild reactional condition while suppressing the formation of by- product by reacting an aromatic bromide with an alcohol and carbon monoxide in the presence of metallic palladium and a basic inorganic substance. CONSTITUTION:An aromatic carboxylic acid ester useful as an intermediate for pharmaceuticals, agricultural chemicals, dyes or pigments, raw material for polymers, plasticizer, preservative, etc., can easily be produced in high yield and efficiency even under mild reactional condition (especially at normal temperature to 150 deg.C under 0.1-5kg/cm<2> pressure) by reacting an aromatic bromide with an alcohol and carbon monoxide in the presence of metallic palladium and a basic inorganic substance (e.g. hydroxide or organic carboxylic acid salt of alkali metal or alkaline-earth metal or alkaline-earth metal oxide) preferably at 50-250 deg.C under <=10kg/cm<2> pressure. Since there is essentially no formation of by-product, the present process is suitable as an industrial process.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention produces aromatic products by reacting an aromatic bromide, an alcohol, and carbon monoxide under low pressure in the presence of a palladium-based catalyst and a basic inorganic substance. The present invention relates to a novel method for producing group carboxylic acid esters J in high yield.

For example, aromatic carboxylic acid esters such as hydroxyl benzoic acid alkyl esters are used for pharmaceuticals, agricultural chemicals, dyes, etc.
It has a wide range of uses including pigment intermediates, polymer raw materials, plasticizers, and preservatives.

[Description of prior art]

A method for producing an aromatic carboxylic acid ester includes, for example, reacting an aromatic carboxylic acid or an acid anhydride or a derivative thereof (carboxylate, acid halide, etc.) with an alcohol or a derivative thereof, Although the method of producing an esterified product is common, there are cases where it is difficult to efficiently produce an aromatic carboxylic acid having both a carboxyl group and an electron-donating substituent at a specific position with high purity. There is a problem in that the aromatic carbonic acid D itself, which is a highly purified substituent-containing aromatic carbonic acid D, which is a raw material used in the above-mentioned general production method, may not be obtained freely.

In addition, as a method for producing aromatic carboxylic acid esters, aromatic halides (halides, chlorides, bromides), alcohol, and carbon monoxide are used in the presence of palladium-based catalysts, nickel-based catalysts, etc. at high temperatures. A method for synthesizing under high pressure is described, for example, in J. Org.

Chem, -39 (No, 23) 3318 (197
4), Bull, Cbem, 5 (Ic.

Jpn, 48(7) 2075 (1975).

However, these known production methods have problems such as low reaction yield, low selectivity, difficulty in recovering expensive catalyst components, and formation of toxic compounds from catalyst components. It was not industrially satisfactory.

In the above-mentioned known production method, in order to improve the yield of aromatic carboxylic acid ester, the above-mentioned reaction is carried out using a second component such as an amine compound together with a palladium-based catalyst. In such cases, there is a problem in that the second component causes a reaction in which not only an aromatic carboxylic acid ester is produced, but also a considerable amount of by-products other than the acid ester (for example, an amide compound) are produced.

[Problems to be Solved] This invention uses an aromatic halide (particularly bromine) to react with alcohol and carbon monoxide in the presence of a palladium catalyst, thereby eliminating the above-mentioned problems. The purpose of the present invention is to provide an industrial production method that can efficiently produce "carboxylic acid ester" and that substantially does not produce other by-products.

[Means to solve problems]

That is, the present invention relates to a method for producing an aromatic carboxylic acid ester, which is characterized by reacting an aromatic bromide, an alcohol, and carbon monoxide in the presence of metal palladium and a basic inorganic substance.

The present invention will be explained in detail below.

The production method of this invention uses a reaction carried out according to the reaction formula shown below.

In the above reaction formula, substituent R is hydrogen, argyl group, alkoxy group, phenoxy group, acyl group, 21,4 group, formyl group, amino group, carbalkoxy group, hydroxyl group, carboxyl group, aryl group. represents at least one substituent selected from the group consisting of a group and a halogen atom, and n represents an integer of O to 4.

R' is methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, pentyl, hexyl,
It shows an alkyl group having 1 to 10 carbon atoms such as octyl, a cycloalkyl group having 5 to 10 carbon atoms such as cyclopentyl and cyclohexyl, and an arylalkyl group such as phenylmethyl and phenylethyl.

Examples of aromatic brominated compounds used in the production method of the present invention include bromobenzene, 0-lm- or p-
Bromotoluene, P-bromostyrene, 4-bromobiphenyl, o-lm- or I)-bromophenol, 4
-bromocatechol, 4-bromoresorcin, 4-bromoguaiacol, 4-bromosalicylaldehyde, 4-
Fromo 5-nitroheradrol, 0-lm- or P-
Methoxybromohenzene, 2,4-dimethoxybromobenzene, 2,5-dimethoxybromobenzene, 4-bromohelatrol, p-phenoxybromobenzene, m-
Bromoacetophenone, p-nitropromohenzene, p
-Chlorbromohenzene, P-bromoaniline, p-promohensaldehyde, p-bromobenzoic acid, methyl p-bromobenzoate, and the like.

The alcohol used in the production method of the present invention may be any primary, secondary or tertiary alcohol having 1 to 10 carbon atoms, such as methanol, ethanol, -propatol, 2-propatol , ■-butanol, 2-butanol, i-butanol, t-butanol, 1-pentanol, 2-pentanol, 1-hexanol, 1-octatool, 2-ethylhexanol, cyclopentanol, cyclohexol, allyl alcohol, crotyl alcohol, hensyl alcohol,
Examples include 2-phenylethanol and cinnamyl alcohol, and aliphatic primary or secondary alcohols having 1 to 6 carbon atoms are particularly suitable.

In the production method of this invention, alcohol can also be used as a reaction solvent, and the amount used is sufficient as long as it is sufficient to dissolve the aromatic bromide J. Although an excess amount may be used, in the present invention, it is preferable that the alcohol be used at a ratio of about 0.5 to 20 moles per mole of aromatic bromide.

The carbon monoxide used in the production method of this invention may be high purity carbon monoxide, but for example, nitrogen gas,
A mixed gas diluted with an inert gas such as carbon dioxide may also be used.

In the production method of the present invention, the pressure of the reaction system (reaction pressure) is 10 kg/c+a or less, but is preferably about normal pressure, and may be slightly pressurized.

If the reaction pressure is too high, the reactivity decreases and the yield of the desired product decreases significantly, which is not appropriate.

The metal palladium used in the production method of the present invention can be used alone, but the metal palladium can also be supported on a porous carrier such as activated carbon, graphite, silica gel, alumina, silica alumina, or molecular sieve.

The amount of metal palladium used is 0.01 to 10% by weight, particularly 0.01 to 10% by weight, based on the aromatic bromide.
The amount is preferably 0.5 to 5% by weight.

Examples of the basic inorganic substances used in the production method of the present invention include (a) hydroxides of alkali metals or alkaline earth metals;
Sodium hydroxide, potassium hydroxide, cerium hydroxide,
Magnesium hydroxide, calcium hydroxide, barium hydroxide, etc. (b) Organic carboxylates of alkali metals or alkaline earth metals; sodium acetate, thorium propionate, thorium benzoate, sodium oxalate, potassium acetate, acetic acid Cesium, calcium acetate, barium acetate, etc.
and (C) alkaline earth metal oxide; magnesium oxide;
Preferred examples include calcium oxide and barium oxide.

The amount of the basic inorganic substance to be used is preferably 0.1 to 10 times, particularly 0.3 to 3 times by mole, per mole of the aromatic bromide.

In the production method of this invention, alcohol can be used as the reaction solvent as described above, and there is no need to use other solvents, but if necessary, diethyl ether, diethylene glycol diethyl ether, Ether solvents such as tetrahydrofuran (1,4-dioxane), aromatic hydrocarbon solvents such as benzene, toluene, xylene, and nitrobenzene, nitrile solvents such as acetonitrile and hendinitrile, or N,
N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, N-methyl-2-pyrrolidone, etc. can be used.

In the production method of this invention, the reaction temperature is 5 to 250
°C1 is preferably about 50 to 200 °C. In the production method of this invention, the reaction temperature is, in particular, room temperature to 15
The reaction can be carried out satisfactorily under mild reaction conditions such as 0°C and reaction pressure: 0.1 to 5 kg/c+fl, and there is virtually no production of by-products, making it easy to achieve the desired results industrially. compounds can be manufactured.

〔Example〕

EXAMPLES Next, the present invention will be described in more detail with reference to Examples and Comparative Examples; however, the present invention is not limited to the following Examples unless the spirit thereof is exceeded.

Example 1 Into a 100 mff glass flask with gas introduction tube and cooling tube, 8.65 g of p-bromophenol, 2.80 g of sodium carbonate, 0.53 g of 10% Pd-C (carbon blank carrier), and 1 -Butanol: Charge 40 mff, and adjust the reaction pressure to normal pressure (1 kg/cJ
) and then - carbon oxide gas (100% concentration)
was supplied into the flask at a flow rate of 4ffi/hr to circulate through the reaction solution, and while stirring the reaction solution, the reaction temperature was increased to 1.
The temperature was raised to 10°C, and the reaction was carried out for 3 hours at the above reaction pressure and temperature to obtain p-hydroxybenzoic acid n-
Butyl ester was produced.

In the above reaction, substantially no aromatic compound by-products were produced.

The results of this reaction are shown in Table 1.

Comparative Example 1 Instead of sodium carbonate, tri-n~butylamine 1
The reaction was carried out in the same manner as in Example 1 except that 1.10 g was used to produce n-butyl p-hydroxybenzoate. During the reaction, 0.21 g of p-hydroxybenzoic acid dibutylamide was produced.

The results of this reaction are shown in Table 1.

Examples 2-5 Potassium carbonate instead of sodium carbonate (Example 2)
, calcium oxide (Example 3), calcium hydroxide (Example 4), or magnesium oxide (Example 5) was used, but in the same manner as in Example 1, n-butyl p-hydroxybenzoate was obtained. Each ester was produced.

In those reactions, substantially no aromatic compound by-products were produced.

The results of each of the above reactions are shown in Table 1.

Examples 6-8 Pd black (Example 6) instead of 10% Pd-C
, 5% Pd5iOz (Example 7), 2% pa-Al2O
P-hydroxybenzoic acid n-butyl ester was produced in the same manner as in Example 1 except that P-hydroxybenzoic acid n-butyl ester was used. In those reactions,
Substantially no aromatic compound by-products were produced.

The results of each of the above reactions are shown in Table 1.

Example 9 The reaction was carried out in the same manner as in Example 1, except that a mixed gas diluted with nitrogen gas (C0 concentration: 50% by volume) was used instead of carbon monoxide gas (CO concentration: 100% by volume). to produce p-hydroxybenzoic acid n-butyl ester. In the reaction, substantially no aromatic compound by-products were produced.

The results of this reaction are shown in Table 1.

Example 10 A reaction was carried out in the same manner as in Example 1, except that the reaction temperature was changed to 110°C and the reaction time was changed to 18 hours, to produce p-hydroxybenzoic acid n-butyl ester. In the reaction, substantially no aromatic compound by-products were produced.

The results of this reaction are shown in Table 1.

Example 11 The reaction was carried out in the same manner as in Example 1 except that 10.85 g of 4-bromoveratrol was used instead of p-bromophenol to produce n-butyl 3.4-dimethoxybenzoate. Ta. In the reaction, substantially no aromatic compound by-products were produced.

The results of this reaction are shown in Table 1.

Comparative Example 2 Tolu-n-butylamine 11 instead of sodium carbonate
．． The reaction was carried out in the same manner as in Example 11 except that 10 g was used to produce n-butyl 3,4-dimethoxybenzoate. In the reaction, 0.42 g of 3,4-dimethoxybenzoic acid di-n-butylamide was produced.

The results of the reaction are shown in Table 1.

Examples 12 to 13 The reaction was carried out in the same manner as in Example 11, except that sodium hydrogen carbonate (Example 12) or acetic acid sulphate (Example 13) was used instead of sodium carbonate, and 3,4 -n-butyl dimethoxybenzoate was produced. In those reactions, substantially no aromatic compound by-products were produced.

The results of the above reaction are shown in Table 1.

Examples 14-17 Instead of 1-butanol, 2-butanol (Example 1
4) In addition to using i-butanol (Example 15), t,-butanol (Example 16), or Hensyl alcohol (Example 17) and setting the reaction temperature shown in Table 2,
The reaction was carried out in the same manner as in Example 9 to produce aromatic carboxylic acid esters corresponding to each alcohol. In those reactions, substantially no aromatic compound by-products were produced.

The results of the above reaction are shown in Table 2.

Example 18 Internal volume 300rrl! 4-Bromohelatrol; 10,85 in a rotary stirring stainless steel autoclave.
g, sodium bicarbonate; 4.62 g, 10% Pd
0.53 g of -C and 40 mp of methanol were charged, and -carbon oxide gas (CO concentration: 100% by volume) was injected under pressure at 2.5 kg/cJG, passed through the reaction solution, and the reaction solution was stirred. Meanwhile, the reaction was carried out at a reaction temperature of 130°C for 8 hours to produce an aromatic carboxylic acid ester.

In the above reaction, substantially no aromatic compound by-products were produced.

The results of the reaction are shown in Table 2.

Examples 19-30 The reaction was carried out in the same manner as in Example 1, except that the amounts and types of aromatic bromides shown in Table 3 were used in place of p---bromophenol, and aromatic carboxylic acids were prepared. produced an ester. In those reactions, substantially no aromatic compound by-products were produced.

The results of the above reactions are shown in Table 3.

Table 2 Table 3 (Part 1) Table 3 (Part 2) [Operations and effects of the present invention] According to the production method of the present invention, an aromatic bromide, an alcohol, and carbon monoxide are mixed in the presence of a palladium-based catalyst. In addition, aromatic carboxylic acid esters can be efficiently produced in high yields by reacting under relatively mild reaction conditions, and moreover, it has the excellent effect of virtually no by-products being produced. show.

Patent applicant: Ube Industries Co., Ltd.

Claims (1)

[Claims] A method for producing an aromatic carboxylic acid ester, which comprises reacting an aromatic bromide, an alcohol, and carbon monoxide in the presence of metal palladium and a basic inorganic substance.