JP2825286B2 - Production method of lactones - Google Patents

Description

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, dicarboxylic anhydride and / or dicarboxylic 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 (Japanese Patent Publication No. 43-6947) 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 hydrogenation 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.

Accordingly, the present applicant has previously proposed a method of hydrogenating in a liquid phase using a ruthenium 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 Laid-Open No. Hei. No. 25771). According to this method, a highly active ruthenium catalyst is used, so that the hydrogenation reaction can be favorably performed under mild conditions.However, in order to industrially produce lactones, the reaction is carried out in a continuous manner. If the method of circulating at least a part of the hydrogen-containing gas to the reaction zone is continued, there is a problem that the activity of the ruthenium catalyst is rapidly reduced.

An object of the present invention is to solve the above-mentioned problems in 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) As a result of studies by the present inventors to achieve the above object, the deactivation of the ruthenium catalyst is caused by the poisoning of the ruthenium catalyst by the carbon monoxide by-produced by the hydrogenation reaction. In order to avoid this poisoning,
The present inventors have found that it is necessary to keep the concentration of carbon monoxide in the gas phase in the hydrogenation reaction zone at a specific value or less, 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 a liquid phase in the presence of a ruthenium catalyst. A method for producing lactones, characterized in that at least a part of the gas is circulated to the reaction zone and the concentration of carbon monoxide in the gas phase of the reaction zone is maintained at 400 ppm (volume) or less.

To explain the present invention in detail, examples of the raw material in the present invention include a saturated or unsaturated dicarboxylic acid having 3 to 7 carbon atoms, an anhydride thereof, or an ester of a dicarboxylic acid such as these. Is preferably a lower alkyl ester. Specifically, for example, maleic acid, fumaric acid, succinic acid, maleic anhydride, succinic anhydride,
Dimethyl maleate, diethyl fumarate, succinic acid
Di-n-butyl and the like are used.

The ruthenium catalyst used in the present invention includes, for example, (a) ruthenium, (b) organic phosphine and (c) pK
A ruthenium-based catalyst containing a conjugate base of an acid in which a is smaller than 2 is exemplified. In some cases, a catalyst further containing (d) a neutral ligand is suitably used.

In order to carry out the hydrogenation reaction according to the method of the present invention, the above-mentioned raw material, catalyst component and solvent are introduced into a reaction vessel, and hydrogen gas is introduced therein. The hydrogen gas may be diluted with a gas inert to the reaction such as nitrogen or carbon dioxide.

The hydrogenation reaction is usually 50-250 ° C, preferably 100-200 ° C
The hydrogen partial pressure in the reaction system is not particularly limited, but is usually 0.1 to 100 kg / cm ² , preferably 1 to 100 kg /
cm ² , more preferably 10 to 50 kg / cm ² . The reaction can be carried out in either a batch mode or a continuous mode. The required reaction time in the case of a batch system is usually 1 to 20 hours. The reaction mixture is cooled and subjected to gas-liquid separation. Unreacted hydrogen gas is separated from accompanying liquid components, and at least a part of the unreacted hydrogen gas is recycled to the hydrogenation reaction zone and reused. The target lactone is collected from the reaction product by a conventional separation and purification means such as distillation and extraction, and the remaining catalyst solution is circulated to the hydrogenation reaction zone.

The present invention, when performing the hydrogenation reaction by the above method, the carbon monoxide concentration in the gas phase in the reaction zone 400ppm
(Capacity) The main point is to keep it below
This prevents a decrease in the activity of the ruthenium catalyst that occurs when the method of circulating the hydrogen-containing gas to the reaction zone is continued, stably continues the hydrogenation reaction for a long period, and industrially advantageously produces lactones. can do.

In the hydrogenation reaction zone, increase the carbon monoxide concentration in the gas phase to 40.
In order to maintain the hydrogen content at 0 ppm (volume) or less, for example, a method of barging a part of the circulating hydrogen-containing gas, or installing a methanation reactor (methanator) in the circulation path of the hydrogen-containing gas, To detoxify carbon monoxide in the gas as methane by passing the gas through. The methanator is filled with a nickel-based catalyst, a ruthenium-based catalyst, etc., which are well-known as carbon monoxide methanation catalysts, and by passing a hydrogen-containing gas at a temperature of about 250 to 300 ° C., carbon monoxide is reduced. Can be easily converted to methane. The reason why the ruthenium catalyst is poisoned by carbon monoxide is not always clear, but because carbon monoxide has an electron donating property, it acts as a ligand to stabilize ruthenium. It is estimated to be.

In order to explain the present invention more specifically, the present invention contains (a) ruthenium, (b) an organic phosphine, and (c) a conjugate base of an acid having a pKa value of less than 2, which is used in the present invention. Specific examples of the ruthenium catalyst which may contain a neutral ligand include the following.

(A) Ruthenium: As ruthenium, both metal ruthenium and ruthenium compounds can be used. As the ruthenium compound, oxides, halides, hydroxides, inorganic acid salts, organic acid salts or complex compounds of ruthenium are used, and specifically, for example, ruthenium dioxide, ruthenium tetroxide, ruthenium dihydroxide, chloride Ruthenium, ruthenium bromide, ruthenium iodide, ruthenium nitrate, ruthenium acetate, ruthenium tris (acetylacetone), sodium hexachlororuthenate, dipotassium tetracarbonylruthenate, ruthenium pentacarbonyl, cyclopentadienyldicarbonylruthenium, dibromotricarbonylruthenium, Chlorotris (triphenylphosphine) hydridoruthenium, bis (tri-n-
(Butylphosphine) tricarbonylruthenium, dodecacarbonyltriruthenium, tetrahydridodecacarbonyltetraruthenium, dicesium octadecacarbonylhexalthenate, undecacarbonylhydridotriruthenate tetraphenylphosphonium and the like. The amount of the metal ruthenium and ruthenium compound used is 0,0 as ruthenium in 1 liter of the reaction solution.
It is from 0001 to 100 mmol, preferably from 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) The conjugate base of an acid having a pKa value of less than 2 The conjugate base of an acid having a pKa value of less than 2 acts as an additional promoter of the ruthenium catalyst, and has a pKa value of 2 or less during the preparation of the catalyst or during the reaction. What is necessary is just to generate a conjugate base of a small acid. 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, nitrous acid, perchloric acid, phosphoric acid, borofluoric acid, hexafluorophosphoric acid, tungstic acid, phosphomobridic acid, phosphotungstic acid, silicon tungstic acid, polysilicic acid, fluorosulfone Inorganic acids such as acids, organic acids such as trichloroacetic acid, dichloroacetic acid, trifluoroacetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, lauric sulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, and ammonium of these acids Salts and phosphonium salts. In addition, conjugate bases of these acids are considered to be produced in the reaction system, and acid derivatives such as acid halides,
The same effect can be obtained by adding in the form of an acid anhydride, an ester, an acid amide or the like. The amount of these acids or salts used is
0.01 to 1000 moles per mole of ruthenium, preferably
It is in the range of 0.1-100 mol, more preferably 0.5-20 mol.

(D) In addition to the above components (a), (b) and (c), the (d) neutral ligand which can be optionally contained includes:
Hydrogen, ethylene, propylene, butene, cyclopentene, cyclohexene, butane, cyclopentadiene, cyclooctadiene, norbonadiene, and other oleins, carbon monoxide, diethyl ether, anisole, dioxane, tetrahydrofuran, acetone, acetophenone, benzophenone, cyclohexanone, propionic acid , Cabronic acid, butyric acid, benzoic acid, ethyl acetate, allyl acetate, benzyl benzoate, oxygenated compounds such as benzyl stearate, nitric oxide, acetonitrile, propionitrile, benzonitrile, cyclohexyl isonitrile,
Butylamine, aniline, toluidine, triethylamine, pyrrole, pyridine, N-methylformamide, acetamide, 1,1,3,3-tetramethylurea, N-methylpyrrolidone, caprolactam, nitrogen-containing compounds such as nitromethane, carbon disulfide, Sulfur-containing compounds such as n-butyl mercaptan, thiophenol, dimethyl sulfide, dimethyl disulfide, thiophene, dimethyl sulfoxide, genyl sulfoxide, tributyl phosphine oxide, ethyl diphenyl phosphine oxide, triphenyl phosphine oxide, diethyl phenyl phosphinate, diphenyl methyl phosphine Carbonate, genenylethyl phosphinate, o, o-dimethylmethylphosphonothiolate, triethyl phosphite, triphenyl phosphate, triethyl phosphate Phosphorus-containing compounds other than organic phosphines, such as phyto, triphenyl phosphate, hexamethylphosphoric triamide, and the like.

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 diethyl 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, propionic 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-
Carboxamides 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.

(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 is not exceeded.

Examples 1-2 and Comparative Examples 1-2 Preparation of the catalyst: 0.039% by weight of ruthenium acetylacetonate, 0.3
7% by weight trioctylphosphine and 0.16% by weight p
-Toluenesulfonic acid was dissolved in triethylene glycol dimethyl ether (triglyme) and heat-treated at 200 ° 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 gas-liquid separator, 6 is a distillation column, and 7 is a methanator.

The above catalyst solution is supplied from the catalyst container 2 to the reactor 1 (10-liter pressure cooker) at a flow rate of 2555 g / hr, and hydrogen gas is supplied from the compressor 3.
At a flow rate of 5.6 Nm ³ / hr, the reactor 1 is supplied with a pressure of 4
It was kept at 0 kg / cm ² G and at a temperature of 200 ° C. On the other hand, succinic anhydride
A raw material liquid composed of 80% by weight 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 365 g / hr to perform a hydrogenation reaction.

The reaction mixture was subjected to gas-liquid separation under normal pressure in a gas-liquid separator 5, and various amounts shown in Table 1 were purged from the separated gas to the outside of the system.
The concentration of carbon monoxide in the gas phase in the reactor 1 was adjusted as shown in Table 1, and the remaining gas was circulated to the reactor 1 via the compressor 3 for use. On the other hand, the reaction product liquid was fed to the distillation column 7 to distill and separate the formed γ-butyro craton and water from the top, and the catalyst solution was extracted from the bottom of the column and circulated to the reactor 1 via the catalyst vessel 2. The results are shown in Table 1. For reference, Table 1 also shows a case where hydrogen gas was not purged as a reference example.

The methanator 7 in the third embodiment FIG. 1, a commercially available packed ruthenium-based catalyst _{(0.5% Ru / Al0 3)} , the system hydrogen gas 70 NL / hr separated by the gas-liquid separator 5 in the method of Example 1 After purging outside, the remaining gas was passed through the methanator 7 at a space velocity (SV) of 3200 at a temperature of 250 ° C., and then circulated through the compressor 3 to the reactor 1. The hydrogenation reaction was carried out in the same manner as in Example 1 except for the other operations. The results are shown in Table 1.

(Effect of the Invention) The method of the present invention is applicable to a hydrogenation reaction when a lactone is produced by hydrogenating dicarboxylic acid, dicarboxylic anhydride and / or dicarboxylic acid ester in a liquid phase using a ruthenium catalyst. At least a part of the used hydrogen-containing gas is circulated to the reaction zone, and the concentration of carbon monoxide in the gas phase of the reaction zone is maintained at 400 ppm (volume) or less, thereby preventing the activity of the ruthenium catalyst from lowering. However, the hydrogenation reaction can be stably continued for a long time, and lactones can be industrially advantageously produced.

[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 gas-liquid separator, 5 is a distillation column, and 7 is a methanator.

Continued on the front page (72) Inventor Hiroshi Gumi 3-10, Utsudori, Kurashiki-shi, Okayama Prefecture Mizushima Plant, Mitsubishi Kasei Co., Ltd. (58) Field surveyed (Int.Cl. ⁶ , DB name) 309/30

Claims (1)

(57) [Claims] 1. A dicarboxylic acid, a dicarboxylic anhydride and / or
Alternatively, in a method for producing lactones by hydrogenating a dicarboxylic acid ester in the liquid phase in the presence of a ruthenium catalyst, at least a part of the hydrogen-containing gas used in the hydrogenation reaction is circulated to the reaction zone, A method for producing lactones, wherein the concentration of carbon monoxide in the gas phase is maintained at 400 ppm (volume) or less.