JP2516836B2 - Method for producing lactones - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing lactones. Specifically, it relates to an improvement in a method for producing a lactone by hydrogenating a dicarboxylic acid, a dicarboxylic acid anhydride and / or a dicarboxylic acid ester in a liquid phase in the presence of a ruthenium catalyst.

(Prior Art) A method for producing a lactone by hydrogenating a dicarboxylic acid, a dicarboxylic acid anhydride and / or a dicarboxylic acid ester has 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), 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), and the like, using a fixed bed or a suspension phase. Is known to carry out a hydrogenation reaction.

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

(Problems to be solved by the invention) However, the conventional method using a solid catalyst such as the above nickel-based catalyst, cobalt-based catalyst, copper-chromium-based catalyst, copper-zinc-based catalyst, the reaction conditions are 250 ℃. However, there is a problem that it is inevitable to adopt severe conditions of above several tens of atmospheres. On the other hand, the method using the homogeneous ruthenium-based catalyst is characterized in that the hydrogenation reaction proceeds under relatively mild conditions, while the catalytic activity is rather low and the catalyst life is short, Further, since halogen is used, there is a problem that the reactor is corroded.

Therefore, the present applicant has previously proposed a method of hydrogenating in a liquid phase using a ruthenium-based catalyst containing a ruthenium, an organic phosphine, and a conjugate base of an acid having a pka value of less than 2 as a catalyst (JP-A-1- 25771 publication). According to this method, since a highly active ruthenium-based catalyst is used, the hydrogenation reaction can be satisfactorily performed under mild conditions by using a small amount of the catalyst, but a catalyst solution obtained by separating lactones from the reaction product is used. If the hydrogenation reaction is circulated in the hydrogenation reaction and the hydrogenation reaction is continued, there is a problem that the yield of the desired lactone decreases and the catalytic activity decreases.

An object of the present invention is to solve the above-mentioned problems in the method using a ruthenium-based catalyst and to industrially advantageously produce a lactone from a dicarboxylic acid, a dicarboxylic acid anhydride and / or a dicarboxylic acid ester. .

(Means for Solving the Problems) The present invention, etc., are the results of examining the cause of a decrease in the yield of lactones and a decrease in catalytic activity when the above hydrogenation reaction is continued using a ruthenium-based catalyst. It was found that a part of the organic phosphine in the catalyst component reacts with the raw material dicarboxylic acid.

As a result of further studies based on the above findings by the present inventor,
The lactones are obtained by hydrogenating a dicarboxylic acid, a dicarboxylic acid anhydride and / or a dicarboxylic acid ester 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 of less than 2. In the case of production, the catalyst liquid obtained by separating the lactones from the hydrogenation reaction product is circulated for the hydrogenation reaction, and the concentration of the free organic phosphine in the liquid phase of the hydrogenation reaction zone is 0.01%.
The present invention has been accomplished by confirming that when the content is kept in the range of 0.1 wt%, the yield of lactones does not decrease and the stable catalytic activity is maintained, so that lactones can be efficiently produced. That is, the gist of the present invention is to include a dicarboxylic acid, a dicarboxylic acid anhydride and / or a dicarboxylic acid ester, (i) ruthenium, (b) an organic phosphine and (c) a conjugate base of an acid having a pka of less than 2. In a method for producing lactones by hydrogenating in a liquid phase in the presence of a ruthenium-based catalyst, a catalyst liquid obtained by separating lactones from a hydrogenation reaction product is circulated in a hydrogenation reaction and A method for producing lactones is characterized in that the concentration of free organic phosphine in the liquid phase is kept in the range of 0.01 to 0.1% by weight.

To explain the present invention in detail, examples of the raw material in the present invention include saturated or unsaturated dicarboxylic acids having 3 to 7 carbon atoms, anhydrides thereof, or esters thereof, and the ester is lower. Alkyl esters are 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-based catalyst according to the present invention will be described in detail later, but includes (i) ruthenium, (b) an organic phosphine, and (c) a ruthenium-based catalyst containing a conjugate base of an acid having a pka of less than 2, or this ruthenium-based catalyst. Examples of the catalyst include (d) a catalyst containing a neutral ligand.

The present invention relates to the production of lactones by hydrogenating the above-mentioned dicarboxylic acid, dicarboxylic acid anhydride and / or dicarboxylic acid ester in the liquid phase in the presence of the above ruthenium-based catalyst to produce lactones from the hydrogenation reaction product. The separated catalyst liquid is circulated in the hydrogenation reaction, and the concentration of free organic phosphine in the liquid phase of the hydrogenation reaction zone is 0.01 to 0.1% by weight,
It is preferable to keep the content in the range of 0.02 to 0.05% by weight. When the concentration of free organic phosphine in the liquid phase exceeds 0.1% by weight, a high-boiling substance is produced as a by-product by reacting with the raw material, while when the concentration of free organic phosphine is less than 0.01% by weight, ruthenium It is considered that even the organic phosphine in the complex is consumed in the side reaction, precipitation of ruthenium metal is observed in the reaction solution, and the catalytic activity is significantly reduced. Furthermore, organic phosphines are very susceptible to oxidation,
It was found to be consumed as organic phosphine oxide during continuous operation, and it is necessary to consider supplementation for that amount.

In order to adjust the concentration of the organic phosphine in the reaction zone to the above range, for example, a supply container for the organic phosphine is installed in the route for circulating the catalyst liquid in the reactor, and the concentration of the free organic phosphine in the catalyst liquid is 0.01 to A method of replenishing the organic phosphine in an amount of 0.1% by weight from this container at any time is adopted.

By such a method, the side reaction based on the reaction between the raw material and the organic phosphine is suppressed, the yield of lactones is improved, and the catalytic activity is stably maintained.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The details of the ruthenium-based catalyst that may contain a ligand are as follows.

(A) Ruthenium: As ruthenium, both metal ruthenium and ruthenium compounds can be used. As the ruthenium compound, ruthenium oxide, halide, hydroxide, inorganic acid salt, organic acid salt or complex compound is used, and specifically, for example, ruthenium dioxide, ruthenium tetroxide, ruthenium dihydroxide, chloride. Ruthenium, ruthenium bromide, ruthenium iodide, ruthenium nitrate, ruthenium acetate, ruthenium acetylacetonate, sodium hexachlororuthenate, dipotassium tetracarbonyl ruthenate, pentacarbonyl ruthenium, cyclopentadienyl dicarbonyl ruthenium, dibromotricarbonyl ruthenium, chlorotris (Triphenylphosphine) hydridoruthenium, bis (tri-n-butylphosphine) tricarbonylruthenium, dodecacarbonyltriruthenium, tetrahydridodecacarbonyltetra Ruthenium, octadecanol carbonyl hexa ruthenate Jiseshiumu, undecalactone carbonyl hydride tri ruthenate tetraphenylphosphonium the like.
The amount of these metal ruthenium and ruthenium compounds used is usually 0.01 as ruthenium in 1 liter of the reaction solution.
~ 100 mmol, preferably 0.1-10 mmol.

(B) Organic phosphine: It is considered that the organic phosphine contributes to suppressing the electronic state of ruthenium of (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 and dimethyl-n-octylphosphine, tricycloalkylphosphines such as tricyclohexylphosphine, triphenylphosphine. Such as triarylphosphines, alkylarylphosphines such as dimethylphenylphosphine, and polyfunctional phosphines such as 1,2-bis (diphenylphosphino) ethane. The amount of organic phosphine used is usually about 0.1 to 100 mol, preferably 3 to 100 mol, per 1 mol of ruthenium.
Is a mole. Further, the organic phosphine can be supplied to the reaction system by itself or in the form of a complex with the ruthenium-based catalyst.

(C) Conjugate base of acid with pka value less than 2: Conjugate base of acid with pka value less than 2 acts as an additional promoter of ruthenium-based catalyst, and has pka value during catalyst preparation or reaction system. Any acid can be used as long as it produces a conjugate base of an acid smaller than 2. The supply form thereof is pka
Bronsted acid having a value less than 2 or various salts thereof is used. Specifically, for example, sulfur, sulfurous acid, nitric acid, nitrous acid, perchloric acid, phosphoric acid, borofluoric acid, hexafluorophosphoric acid, tungstic acid, phosphomolybdic acid, phosphotungstic acid, silicon tungstic acid, polysilicic acid, fluorosulfone. Inorganic acids such as acids, trichloroacetic acid, dichloroacetic acid trifluoroacetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, laurylsulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, and other organic acids, or ammonium of these acids Examples thereof include salts and phosphonium salts. Further, the same effect can be obtained even if the conjugate base of these acids is added in the form of an acid derivative, such as an acid halide, an acid anhydride, an ester or an acid amide, which is considered to be produced in the reaction system. The amount of these acids or salts thereof used is usually 0.5 to 100 mol, preferably 1 to 20 mol, per 1 mol of ruthenium.

In addition to the components (a), (b) and (c) above, (d) a neutral ligand which may be optionally contained,
Olefins such as hydrogen, ethylene, propylene, butene, cyclopentene, cyclohexene, butadiene, cyclopentadiene, cyclooctadiene, norbonadiene, diethyl ether, anisole, dioxane, tetrahydrofuran, acetone, acetophenone, benzophenone, cyclohexanone, propionic acid, caproic acid, Oxygen-containing compounds such as butyric acid, benzoic acid, ethyl acetate, allyl acetate, benzyl benzoate and benzyl stearate,
Nitric oxide, acetonitrile, propionitrile, benzonitrile, cyclohexylisonitrile, butylamine, aniline, toluidine, triethylamine, pyrrole, pyridine, N-methylformamide, acetamide, 1,1,3,3-tetramethylurea, N-methylpyrrolidone , Nitrogen-containing compounds such as caprolactam and nitromethane,
Sulfur-containing compounds such as carbon disulfide, n-butyl mercaptan, thiophenol, dimethyl sulfide, dimethyl disulfide, thiophene, dimethyl sulfoxide and diphenyl sulfoxide, tributylphosphine oxide,
Ethyldiphenylphosphine oxide, triphenylphosphine oxide, diethylphenylphosphinate,
Phosphorus-containing compounds other than organic phosphines such as diphenylmethylphosphinate, diphenylethylphosphinate, o, o-dimethylmethylphosphonothiolate, triethylphosphite, triphenylphosphite, triethylphosphate, triphenylphosphate, and hexamethylphosphoric triamide. Compounds.

The method of the present invention can be carried out by using the starting material or the reaction product itself as a solvent without using a solvent, but other solvents can be used in addition to the starting material.

Examples of such a solvent include diethyl ether,
Ethers such as anisole, tetrahydrofuran, ethylene glycol diethyl ether, triethylene glycol dimethyl ether, dioxane; ketones such as acetone, methyl ethyl ketone, acetophenone; alcohols such as methanol, ethanol, n-butanol, benzyl alcohol, ethylene glycol, diethylene glycol; Phenols; carboxylic acids such as formic acid, acetic acid, propionic acid, toluic acid; methyl acetate, acetic acid n
-Esters such as butyl and benzyl benzoate; aromatic hydrocarbons such as benzene, toluene, ethylbenzene and tetraphosphoric acid; 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; Sulfonic acids such as dimethyl sulfone and tetramethylene sulfone; Sulfoxides such as dimethyl sulfoxide and diphenyl sulfoxide; Clactones such as γ-butyrolactone and ε-caprolactone; Triglyme (triethylene glycol dimethyl ether) , Tetraglyme (tetraethylene glycol dimethyl ether), polyethers such as 18-crown-6, nitriles such as acetonitrile and benzonitrile, and carbonic acid esters such as dimethyl carbonate and ethylene carbonate.

To prepare the ruthenium-based catalyst, for example, a solution containing the above-mentioned catalyst component may be heat-treated in an inert gas atmosphere. It is considered that the obtained catalyst forms a complex structure in which about 2 to 4 organic phosphines are coordinated per 1 atom of ruthenium. Then, only the excess organic phosphine that does not form a complex is quantified as free phosphine by gas chromatography. In addition, pk
When a conjugate base of an acid in which a is smaller than 2 is coexisted,
Since the concentration of free organic phosphine is further reduced, it is considered that a stable complex is also formed in the solution between the conjugated base and the organic phosphine.

In order to carry out the hydrogenation reaction by the method of the present invention, a catalyst liquid containing the above-mentioned catalyst components in which the concentrations of the raw material and the organic phosphine are adjusted in advance is introduced into the reaction vessel, and hydrogen is further introduced. Hydrogen may be diluted with a reaction-inert gas such as nitrogen or carbon dioxide. The reaction temperature is usually 50 to 250 ° C, preferably 100 to 220 ° C.
The hydrogen partial pressure in the reaction system is not particularly limited, but usually 0.1 to 100 kg / cm ² G, preferably 1 to 50 k in industrial practice.
It is g / cm ² G. The target lactone is collected from the reaction product solution by a usual separation and purification means such as distillation and extraction.

The catalyst solution from which the lactones have been separated constantly checks its composition, and in order to keep the concentration of the organic phosphine in the catalyst solution always at the above-mentioned predetermined concentration, the organic phosphine is appropriately replenished during the circulation process to provide a reaction vessel. Circulate to.

(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 unless the gist thereof is exceeded.

The reaction product and free organic phosphine were analyzed by gas chromatography.

Example 1 Preparation of catalyst solution: 0.296 g of ruthenium acetylacetonate, 1.11 g of trioctylphosphine and 0.485 g of p-toluenesulfonic acid.
Was dissolved in 238 g of triethylene glycol dimethyl ether, and heat-treated at 200 ° C. for 2 hours in a nitrogen atmosphere to prepare a catalyst solution. The concentration of free trioctylphosphine in the catalyst solution was 0.041% by weight.

Hydrogenation reaction: The total amount of the above catalyst solution was charged into a 500 ml SUS pressure vessel, 60 g of succinic anhydride was further added and the temperature was raised to 180 ° C., and the hydrogen pressure was 40 kg / c.
The hydrogenation reaction was carried out at m ² G for 1 hour.

When the reaction solution was analyzed, the conversion rate of succinic anhydride was 71.
%, And the selectivity for γ-butyrolactone was 98%. In addition, the concentration of free trioctylphosphine in the reaction solution dropped to 0.02% by weight.

Example 2 A hydrogenation reaction was carried out using the flow reactor 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 an organic phosphine container.

Preparation of catalyst solution: 0.39 g of ruthenium acetylacetonate, 3.70 g of trioctylphosphine and 1.60 g of p-toluenesulfonic acid were dissolved in triethylene glycol dimethyl ether to make a total volume of 1000 ml. The catalyst solution was prepared by heating for a period of time and charged into the catalyst container 2. The concentration of free traoctylphosphine in the catalyst solution is
It was 0.043% by weight.

Hydrogenation reaction: This catalyst solution was supplied from the catalyst container 2 to the reactor 1 (500 ml pressure kettle) at a flow rate of 131 g / hr, and hydrogen gas was supplied from the compressor 3 to 3
Supply to reactor 1 at a flow rate of 20 Nl / hr and set reactor 1 pressure to 4
The temperature was maintained at 205 ° C. at 0 kg / cm ² G. On the other hand, a raw material liquid consisting 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 19 g / hr to carry out the hydrogenation reaction.

The reaction mixture was introduced into the gas-liquid separator 5 to barge the waste gas. The reaction product liquid after gas separation is sent to the distillation column 6,
Γ-butyrolactone and water produced from the top of the column are separated by distillation,
The catalyst liquid was extracted from the bottom of the tower and circulated in the catalyst container 2. On the other hand, the concentration of free trioctylphosphine in the catalyst solution
Trioctylphosphine was continuously supplied from the organic phosphine container 7 so as to maintain 0.04% by weight.

When the operation was continued for 30 days by such a method and the product was analyzed, the selectivity and the yield of γ-butyrolactone were 96.3%, and the raw material conversion rate after 5 days from the reaction start was 100%.
%Met.

Example 3 The operation was continued for 30 days in the same manner as in Example 2 except that the concentration of free trioctylphosphine in the catalyst solution was maintained at 0.10% by weight, and the product was analyzed. The selectivity of γ-butyrolactone is 93.9%,
The yield is 93.0%, and the raw material conversion rate after 5 days from the start of the reaction is
It was 99%.

Comparative Example 1 In Example 2, operation was continued for 30 days in the same manner as in Example 2 except that the concentration of free trioctylphosphine in the catalyst solution was maintained at 0.15% by weight, and the product was analyzed. The selectivity of γ-butyrolactone is 87.0%,
The yield was 85.3%, and the raw material conversion rate after 5 days from the start of the reaction was
It was 98%.

Comparative Example 2 In Example 2, operation was continued for 30 days in the same manner as in Example 2 except that the concentration of free trioctylphosphine in the catalyst solution was maintained at 0.20% by weight, and the product was analyzed. The selectivity of γ-butyrolactone is 67.8%,
The yield was 65.1%, and the raw material conversion rate after 5 days from the start of the reaction was
It was 96%.

Examples 4 to 8 and Comparative Examples 3 to 4 In Example 2, the hydrogenation reaction was carried out in the same manner as in Example 2 except that trioctylphosphine was not supplied from the container 7.

Table 1 shows the free trioctylphosphine (TOP) concentration, the raw material conversion rate, and the γ-butyrolactone (GBL) selectivity in the reaction solution after 1 to 5 days from the start of the reaction. In addition, as a comparative example, the results at 6 days and 7 days after the start of the reaction are also shown in Table 1.

As shown in Table 1, the concentration of free trioctylphosphine decreased to 0.005% by weight after 6 days from the start of the reaction.
After 1 day, it became 0.001% by weight or less, and the selectivity of γ-butyrolactone decreased significantly.

(Effect of the Invention) According to the method of the present invention, when a lactone is produced by hydrogenating a dicarboxylic acid, a dicarboxylic acid anhydride and / or a dicarboxylic acid ester in a liquid phase using a ruthenium catalyst, hydrogenation is performed. The catalyst liquid obtained by separating the lactones from the reaction product is recycled for the hydrogenation reaction, and the concentration of the free organic phosphine in the liquid phase of the hydrogenation reaction zone is 0.01%.
By maintaining the content in the range of 0.1 wt% to 0.1% by weight, the yield of lactones is improved and the catalytic activity is stably maintained, which is of great value in industrial implementation.

[Brief description of drawings]

FIG. 1 is 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, 6 is a distillation column, and 7 is an organic phosphine container.

Continued Front Page (72) Hiroshi Gumi Hiroshi Gumi 3-10 Shiodori, Kurashiki City, Okayama Prefecture Mizushima Plant, Mitsubishi Kasei Co., Ltd. (56) Reference JP-A-1-25771 (JP, A) JP-A-1- 221373 (JP, A)

Claims (1)

(57) [Claims] 1. A dicarboxylic acid, a dicarboxylic acid anhydride and / or
Alternatively, the dicarboxylic acid ester may be (i) ruthenium,
(B) A method for producing a lactone by hydrogenating in a liquid phase in the presence of a ruthenium-based catalyst containing a conjugated base of an acid having an organic phosphine and (c) pka of less than 2, a hydrogenation reaction product The catalyst solution from which the lactones have been separated is circulated in the hydrogenation reaction, and the concentration of free organic phosphine in the liquid phase of the hydrogenation reaction zone is adjusted to 0.01 to 0.
A method for producing lactones, which is characterized in that the content is kept in the range of 1% by weight.