JP2785967B2 - Method for producing lactones - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing lactones.
More specifically, the present invention relates to an improvement in a method for producing lactones by hydrogenating dicarboxylic acid, dicalibonic anhydride and / or diclavonic acid ester in a liquid phase.

(Prior Art) Methods for producing lactones by hydrogenating dicarboxylic acids, dicarboxylic anhydrides and / or dicarboxylic esters have been studied for a long time, and many proposals have been made so far. For example, as a catalyst, a nickel-based catalyst (JP-B-48-6947) and a cobalt-based catalyst (JP-A-51-9505)
No. 7), a copper-chromium catalyst (Japanese Patent Publication No. 38-20119), a copper-zinc catalyst (Japanese Patent Publication No. 42-14463), etc., using a fixed bed or a suspension phase for hydrogenation. Methods for performing the reaction are known.

On the other hand, a method of performing the above-described oxygenation reaction using a homogeneous ruthenium-based catalyst is also known, for example, US Pat.
No. 7 describes a process for producing lactones by hydrogenation under a pressure of 40 to 400 psi using a ruthenium-based catalyst of the type [RuXn (PR ₁ R ₂ R ₃ ) xLy], and US Pat. No. 4,485,246. Describes that a hydrogenation reaction using a similar catalyst is carried out in the presence of an organic amine.

(Problems to be Solved by the Invention) However, in the conventional method using a solid catalyst such as a nickel-based catalyst, a cobalt-based catalyst, a copper-chromium-based catalyst, and a copper-zinc-based catalyst, the reaction conditions are several tens of atmospheres. There was a problem that adoption of the above severe conditions was inevitable. On the other hand, the method using the homogeneous ruthenium-based catalyst,
Although the hydrogenation reaction proceeds under relatively mild conditions, the catalyst activity is rather low, the catalyst life is short, and the use of halogen causes corrosion of the reactor. There's a problem.

Therefore, the present applicant has previously proposed a method of hydrogenating in a liquid phase using a ruthenium-based catalyst containing ruthenium, an organic phosphine, and a conjugate base of an acid having a pKa value smaller than 2 as a catalyst (Japanese Patent Application Laid-Open No. Hei 1-1990). No. 25771). In this method, a highly active ruthenium catalyst is used, so that the hydrogenation reaction can be favorably performed under mild conditions. However, the hydrogenation reaction is carried out using dicarboxylic acid, dicarboxylic anhydride and / or dicarboxylic acid ester as a raw material. If the reaction is continued, high-boiling by-products are formed in the reaction zone due to decomposition or polycondensation, and the yield of lactones is reduced.

An object of the present invention is to solve the above-mentioned problems of the method using a ruthenium catalyst, and to industrially advantageously produce lactones from dicarboxylic acids, dicarboxylic anhydrides and / or dicarboxylic esters. .

(Means for Solving the Problems) The present inventors have studied to achieve the above object, and as a result, hydrogenated dicarboxylic acid, dicarboxylic anhydride and / or dicarboxylic acid ester in a liquid phase using a ruthenium catalyst. When the concentration of diols produced by hydrogenation of the raw materials in the hydrogenation process in the hydrogenation reaction zone is kept at 5% by weight or less in the production of lactones,
The present inventors have found that the amount of the high-boiling by-products can be reduced, and have achieved the present invention. That is, the gist of the present invention is to provide a method for producing a lactone by hydrogenating a dicarboxylic acid, a dicarboxylic anhydride and / or a dicarboxylic acid ester in the liquid phase in the presence of a ruthenium catalyst. Lactones, characterized in that the concentration of lactone is maintained at 5% by weight or less.

To explain the present invention in detail, as the raw material in the present invention, a saturated or unsaturated dicarboxylic acid having 3 to 7 carbon atoms, an anhydride thereof, or an ester of a dicarboxylic acid thereof, As the ester, a lower alkyl ester is preferred. Specifically, for example, maleic acid,
Fumaric acid, succinic acid, maleic anhydride, succinic anhydride, dimethyl maleate, diethyl fumarate, di-n-butyl succinate and the like are used.

The ruthenium catalyst used in the present invention is not particularly limited, and examples thereof include (a) ruthenium, (b) an organic phosphine, and (c) a ruthenium-based catalyst containing a conjugate base of an acid having a pKa smaller than 2. Accordingly, a catalyst further containing (d) a neutral ligand is preferably used.

The present invention relates to a method for producing a lactone by hydrogenating the above-mentioned dicarboxylic acid, dicarboxylic anhydride and / or dicarboxylic acid ester in the liquid phase in the presence of the above-mentioned ruthenium catalyst. The main point is to keep the concentration of diols produced by hydrogenation at 5% by weight or less, preferably at 3% by weight or less.

Since the diols formed in the hydrogenation process have high reactivity, they are easily polycondensed with the dicarboxylic acid, dicarboxylic anhydride or dicarboxylic acid formed by hydrolysis of the dicarboxylic acid ester as the raw material under the hydrogenation reaction conditions. Reacts to produce high-boiling by-products mainly composed of polyester etc., but the concentration of diols in the hydrogenation reaction zone is reduced to 5% by weight.
Or less, preferably 3% by weight or less,
The amount of high-boiling by-products can be significantly reduced.

As a method for maintaining the concentration of diols in the hydrogenation reaction zone at 5% by weight or less, for example, a large excess of hydrogen gas is passed through the hydrogenation reaction zone, and the diols are reacted with the reaction product by stripping the hydrogen gas. A method of extracting the reaction solution together with the lactones out of the reaction zone, a method of adjusting the concentration of the diols by controlling the ratio of the raw material and the solvent, or a method of extracting a part of the reaction solution from the reaction zone and distilling the catalyst solution and the diol. And a method in which only the catalyst solution is circulated to the reaction zone.

By such a method, the production of high boiling substances based on diols is suppressed, and the yield of lactones is improved.

 Hereinafter, the present invention will be described in more detail.

The present invention contains (a) ruthenium, (b) an organic phosphine, and (c) a conjugate base of an acid having a pKa value smaller than 2 and may optionally contain a neutral ligand. The details of the ruthenium catalyst are as follows.

(A) Ruthenium: As ruthenium, both metal ruthenium and ruthenium compounds can be used. As the ruthenium compound, an oxide of ruthenium, a halide, a hydroxide, an inorganic acid salt, an organic acid salt or a complex compound is used.Specifically, for example, ruthenium dioxide, ruthenium tetroxide,
Ruthenium dihydroxide, ruthenium chloride, ruthenium bromide, ruthenium iodide, ruthenium nitrate, ruthenium acetate, ruthenium tris (acetylacetone), sodium hexachlororuthenate, dipotassium tetracarbonylruthenate, ruthenium pentacarbonylruthenium, cyclopentadienyl dicarbonylruthenium , Dibromotricarbonylruthenium, chlorotris (triphenylphosphine) hydridoruthenium, bis (tri-n-butylphosphine) tricarbonylruthenium, dodecarbonyltriruthenium, tetrahydridodecacarbonyltetraruthenium, octadecarbonylhexaruthenate dicesium, And tetraphenylphosphonium decacarbonyl hydride triruthenate and the like.
The amount of the metal ruthenium and ruthenium compound used is 0.001 to 1 as ruthenium in 1 liter of the reaction solution.
The amount is 00 mmol, preferably 0.001 to 10 mmol.

(B) Organic phosphine: Organic phosphine is considered to contribute to controlling the electronic state of ruthenium (a), which is the main catalyst, and stabilizing the active state of ruthenium. Specific examples of the organic phosphine include trialkylphosphines such as tri-n-octylphosphine, tri-n-butylphosphine, dimethyl-n-octylphosphine, tricycloalkylphosphines such as tricyclohexylphosphine, and triphenylphosphine. And alkylarylphosphines such as dimethylphenylphosphine, and polyfunctional phosphines such as 1,2-bis (diphenylphosphino) ethane. The amount of organic phosphine used is usually ruthenium 1
About 0.1 to 1000 mol, preferably 1 to 100 mol
Is a mole. The organic phosphine can be supplied to the reaction system by itself or in the form of a complex with a ruthenium catalyst.

(C) Conjugated base of an acid having a pKa value of less than 2: A conjugate base of an acid having a pKa value of less than 2 acts as an ineffective promoter of a ruthenium catalyst, and has a pKa value of 2 during catalyst preparation or in a reaction system. What is necessary is just to generate a conjugate base of a smaller acid, and as a supply form, Bronsted acid having a pKa value smaller than 2 or various salts thereof are used. Specifically, for example, sulfuric acid, sulfurous acid, nitric acid,
Inorganic acids such as nitrous acid, perchloric acid, phosphoric acid, borofluoric acid, hexafluorophosphoric acid, tungstic acid, phosphomolybdic acid, phosphotungstic acid, silicon tungstic acid, polysilicic acid, fluorosulfonic acid, etc., trichloroacetic acid, dichloroacetic acid, Organic acids such as trifluoroacetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, laurylsulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid,
Alternatively, ammonium salts and phosphonium salts of these acids may be mentioned. The same effect can be obtained by adding these conjugate bases in the form of an acid derivative which is considered to be formed in the reaction system, for example, an acid halide, acid anhydride, ester, acid amide or the like. These acids or salts thereof are used in an amount of 0.01 to 1000 mol, preferably 0.1 to 1 mol of ruthenium.
It is in the range of 1 to 100 mol, more preferably 0.5 to 20 mol.

(D) In addition to the above components (a), (b) and (c), the (d) neutral ligand which can be optionally contained includes:
Olefins such as hydrogen, ethylene, propylene, butene, cyclopentene, cyclohexene, butadiene, cyclopentadiene, cyclooctadiene, norbonadiene, carbon monoxide, diethyl ether, anisole, dioxane, tetrahydrofuran, acetone, acetophenone, benzophenone, cyclohexanone, Oxygenated compounds such as propionic acid, caproic acid, butyric acid, benzoic acid, ethyl acetate, aryl acetate, benzyl benzoate, benzyl stearate, nitric oxide, acetonitrile, propionitrile, benzonitrile, cyclohexyl isonitrile, butylamine, aniline, toluidine , Triethylamine, pyrrole, pyridine, N-methylformamide, acetamide, 1,1,3,3-tetramethylurea, N-
Nitrogen-containing compounds such as methylpyrrolidone, caprolactam, and nitromethane; carbon disulfide, n-butylmethylcaptan, thiophenol, dimethylsulfide, dimethyldisulfide, thiophene, dimethylsulfoxide, sulfur-containing compounds such as diphenylsulfoxide, tributylphosphine oxide, and ethyl Diphenylphosphine oxide, triphenylphosphine oxide, diethylphenylphosphinate, diphenylmethylphosphinate,
Examples include phosphorus-containing compounds other than organic phosphines such as diphenylethyl phosphinate, o, o-dimethylmethylphosphonothiolate, triethyl phosphite, triphenyl phosphite, triethyl phosphate, triphenyl phosphate, and hexamethylphosphoric triamide.

The method of the present invention can be carried out without using a solvent and using the raw material itself as a solvent. However, other solvents can be used in addition to the raw material.

Such solvents include, for example, diethyl ether,
Ethers such as anisole, tetrahydrofuran, ethylene glycol diethylene ether, triethylene glycol dimethyl ether, and dioxane; ketones such as acetone, methyl ethyl ketone and acetophenone; alcohols such as methanol, ethanol, n-butanol, benzyl alcohol, ethylene glycol and diethylene glycol Phenols; carboxylic acids such as formic acid, acetic acid, pyropionic acid and toluic acid; methyl acetate, acetic acid n
Esters such as butyl and benzyl benzoate; aromatic hydrocarbons such as benzene, toluene, ethylbenzene and tetralin; aliphatic hydrocarbons such as n-hexane, n-octane and cyclohexane; halogenation such as dichloromethane, trichloroethane and chlorobenzene. Hydrocarbons; nitrated hydrocarbons such as nitromethane and nitrobenzene; N, N-dimethylformamide, N, N-dimethylacetamide, N-
Carboxylic acid amides such as methylpyrrolidone; other amides such as hexamethylphosphoric triamide, N, N, N ', N'-tetraethylsulfamide; N, N'-dimethylimidazolidone, N, N, N, Ureas such as N-tetramethylurea; sulfones such as dimethyl sulfone and tetramethylene sulfone; sulfoxides such as dimethyl sulfoxide and diphenyl sulfoxide; lactones such as γ-butyrolactone and ε-caprolactone; triglyme (triethylene glycol dimethyl ether) Polyethers such as tetraglyme (tetraethylene glycol dimethyl ether) and 18-crown-6; nitriles such as acetonitrile and benzonitrile; and carbonic esters such as dimethyl carbonate and ethylene carbonate.

In order to carry out the hydrogenation reaction according to the method of the present invention, a raw material, the above-mentioned catalyst component and, if desired, a solvent are introduced into a reaction vessel, and hydrogen is introduced therein. Hydrogen may be diluted with an inert gas such as nitrogen or carbon dioxide. The reaction temperature is usually 50 to 250 ° C, preferably 100 to
200 ° C. Although the hydrogen partial pressure in the reaction system is not particularly limited, it is usually 0.1 to 100 kg / cm ² , preferably 1 to 100 kg / cm ² in industrial practice.
Is a ~50kg / cm ^2. The reaction can be carried out in either a batch system or a continuous system. In the case of the batch system, the required reaction time is usually 1 to 20 hours.

The target lactones can be collected from the reaction product liquid by ordinary separation and purification means such as distillation and extraction.
The distillation residue is circulated to the reaction system as a catalyst component. In the present invention, the concentration of diols in the hydrogenation reaction zone is maintained at 5% by weight or less by the various means described above when performing the hydrogenation reaction in this manner.

(Examples) Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples as long as the gist of the present invention is not exceeded.

Example 1 Preparation of catalyst solution: 0.056% by weight ruthenium acetylacetonate, 0.5
1% by weight of trioctylphosphine and 0.22% by weight of p
-Dissolve toluenesulfonic acid in 2000 ml of tetraethylene glycol dimethyl ether (tetraglyme) and add
Heat treatment was performed at 0 ° C. for 2 hours to prepare a catalyst solution.

Hydrogenation reaction: The hydrogenation reaction was carried out using the flow-type reaction equipment shown in FIG. In FIG. 1, 1 is a reactor, 2 is a catalyst container, 3 is a compressor, 4 is a raw material container, 5 is a cooler, 6 is a gas-liquid separator, 7 is a first distillation column, and 8 is a second distillation column. It is.

The catalyst liquid was supplied from the catalyst container 2 to the reactor 1 at a flow rate of 500 ml / hr, while hydrogen gas was supplied from the compressor 3 to the reactor 1 (500 ml pressure cooker) at a flow rate of 800 Nl / hr. Pressure 4
The temperature was kept at 0 kg / cm ² G and the temperature was 200 ° C. On the other hand, a raw material liquid composed of 80% by weight of succinic anhydride and 20% by weight of γ-butyrolactone was continuously supplied from the raw material container 4 to the reactor 1 at a flow rate of 100 g / hr to perform a hydrogenation reaction.

The reaction mixture is cooled to 60 ° C. in a cooler 5 and a gas-liquid separator 6
The mixture was subjected to gas-liquid separation under normal pressure to purge waste gas. The reaction product liquid is fed to the first distillation column 7 to distill and separate γ-butyrolactone and water produced from the top of the column. The catalyst solution is withdrawn from the bottom of the column, circulated from the pipe 9 to the catalyst vessel 2, and a part of the catalyst liquid is removed. tube
The mixture was fed to the second distillation column 8 at a flow rate of 10 to 50 ml / hr, 1,4-butanediol was separated by distillation from the top of the column, and the bottoms were withdrawn from the bottom of the column and circulated to the catalyst vessel 2. The operating conditions of the first distillation column 7 were 20 stages, the top vacuum degree was 30 mm of mercury, and the reflux ratio was 3. The operating conditions of the second distillation column 8 were 30 stages and the top vacuum degree was 10 mm.
The mercury column was mm and the reflux ratio was 3.

When the reaction was carried out for 3 consecutive days by such a method, a stable reaction result was shown from 2 days onward. The analysis of the product in the reactor 1 and the product twice by gas chromatography was performed twice a day, and the diol concentration and The yield of γ-butyrolactone was determined. The catalyst solution was analyzed by gel permeation chromatography (GPC) to determine the amount of high-boiling by-products. The results are shown in Table 1.

Example 2 The reaction was carried out in exactly the same manner as in Example 1 except that the amount of the catalyst solution fed from the tube 10 to the second distillation column 8 (50 ml / hr) was 12 ml / hr. Table 1 shows the results.

Example 3 The flow rate of hydrogen gas to the reactor 1 in Example 1 (800 N
(l / hr) was set to 8000 Nl / hr, and the reaction was carried out exactly as in Example 1 except for the above. Table 1 shows the results.

Comparative Example 1 The reaction was carried out in exactly the same manner as in Example 1 except that the amount of the solvent liquid fed from the tube 10 to the second distillation column 8 (50 ml / hr) in Example 1 was 5 ml / hr. Table 1 shows the results.

Comparative Example 2 In Comparative Example 1, the reaction was performed in the same manner as in Comparative Example 1, except that the reaction temperature of the reactor 1 was set to 208 ° C. Table 1 shows the results.

(Effects of the Invention) According to the present invention, when a lactone is produced by oxidizing dicarboxylic acid, dicarboxylic anhydride and / or dicarboxylic acid ester in a liquid phase using a ruthenium catalyst, the lactone is produced in a hydrogenation reaction zone. By maintaining the concentration of diols produced by hydrogenation of the raw material at 5% by weight or less, the amount of high-boiling by-products is reduced and the yield of lactones is improved, which is of great industrial value.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a process diagram of a flow-type reaction facility used for carrying out the present invention. In the figure, 1 is a reactor, 2 is a catalyst container, 3 is a compressor, 4 is a raw material container, 5 is a cooler, 6 is a gas-liquid separator, 7 is a first distillation column,
8 is a second distillation column.

Continuation of the front page (56) References JP-A-64-25711 (JP, A) JP-B-48-30271 (JP, B1) JP-B-46-5692 (JP, B1) (58) Fields investigated (Int .Cl. ⁶ , DB name) C07D 307/32

Claims (1)

(57) [Claims] 1. A dicarboxylic acid, a dicarboxylic anhydride and / or
Or a method for producing lactones by hydrogenating a dicarboxylic acid ester in a liquid phase in the presence of a ruthenium catalyst, wherein the concentration of diols in the hydrogenation reaction zone is maintained at 5% by weight or less. Manufacturing methods.