CN101010310B - Method for decomposing ester oligomer and method for producing C4 compound - Google Patents

Abstract

The present invention relates to a method for decomposing ester oligomers and a method for producing _C4 compounds. The object of the present invention is to provide a method for decomposing ester oligomers containing succinic acid and/or 4-hydroxybutyric acid and 1,4-butanediol as constituents, especially to provide a A method for decomposing ester oligomers produced as by-products in a method for producing butyrolactone; further providing a method for producing an industrially useful C4 product group, particularly providing a method for producing γ-butyrolactone. The decomposition method of the ester oligomer of the present invention is as follows: the aqueous solution of the ester oligomer containing succinic acid and/or 4-hydroxybutyric acid and 1,4-butanediol as constituents is mixed with a solid acid catalyst under heating contacting, decomposing the ester oligomer into its constituents, simultaneously converting 1,4-butanediol to tetrahydrofuran, and/or in the case of containing 4-hydroxybutyric acid as a constituent of said ester oligomer , converting 4-hydroxybutyric acid to γ-butyrolactone.

Description

Decomposition method of ester oligomer and production method of C4 compound

technical field

The present invention relates to a method for decomposing ester oligomers and a method for producing compounds having 4 carbon atoms (hereinafter referred to as "C4 compounds").

Background technique

Chemicals group with four carbon atoms (C4 product group), such as γ-butyrolactone, 1,4-butanediol, tetrahydrofuran, succinic acid and N-methylpyrrolidone, etc., are used in various solvents and polymerization An important group of intermediates for raw materials. In recent years, the demand for such C4 products is increasing. In particular, γ-butyrolactone is useful not only as an excellent solvent itself but also as an important intermediate of various substances such as pyrrolidones, and various methods for producing γ-butyrolactone have been developed. For example, as shown in JP-A-3-26340 and JP-A-3-232874, the hydrogenation reaction of succinic anhydride and the dehydrogenation reaction of 1,4-butanediol have been developed. In addition, the hydrogenation reaction (Journal of catalysis 194,188-197, 2000) and the dehydrogenation reaction of 1,4-butanediol (JP-A-2001-240595 bulletin) of the same succinic anhydride have also been reported using a ruthenium complex catalyst ). Many of these γ-butyrolactone production methods have high yields, but since high-boiling compounds are sometimes produced as by-products, raw materials such as succinic anhydride, succinic acid, 1,4-butanediol, or maleic anhydride are increased. the cost of. Therefore, if these by-product high boiling point compounds can be decomposed and regenerated as raw materials, a more efficient production method of γ-butyrolactone can be determined. Therefore, it is desirable to develop such a method.

Patent Document 1: JP-A-3-26340

Patent Document 2: JP-A-3-232874

Patent Document 3: JP-A-2001-240595

Non-Patent Document 1: Journal of catalysis 194, 188-197, 2000

Contents of the invention

The object of the present invention is to provide a method for decomposing ester oligomers (high boiling point compounds) containing succinic acid and/or 4-hydroxybutyric acid and 1,4-butanediol as constituents, especially to provide a A method for decomposing high boiling point compounds (ester oligomers) generated as by-products in a method for producing gamma-butyrolactone; further providing a method for producing an industrially useful C4 product group, in particular providing a A method for producing gamma-butyrolactone.

The inventors of the present invention conducted intensive studies to solve the above problems, and as a result found that in the manufacture of C4 product group, particularly in the manufacture of γ-butyrolactone, high boiling point compounds produced as by-products are those containing succinic acid and / or 4-hydroxybutyric acid and 1,4-butanediol as constituent ester oligomers, it has also been found that by using a solid acid catalyst to process an aqueous solution containing this high boiling point compound (ester oligomer), the The high boiling point compound is decomposed (hydrolyzed) into an aqueous solution containing succinic acid and/or 4-hydroxybutyric acid and 1,4-butanediol as constituent components of the high boiling point compound (ester oligomer). However, the present inventors have also found that if succinic acid and/or 4-hydroxybutyric acid and 1,4-butanediol (obtained by decomposing the high-boiling point compound) coexist, they are converted into high-boiling point compounds (ester oligomerization) things). Once succinic acid and/or 4-hydroxybutyric acid and 1,4-butanediol are converted into high boilers (ester oligomers), the individual constituents cannot be separated and cannot be utilized. Therefore, in order to prevent further conversion of succinic acid and/or 4-hydroxybutyric acid and 1,4-butanediol into high-boiling point compounds (ester oligomers), the present inventors conducted intensive studies and found that by heating By contacting the high boiling point compound (ester oligomer) with a solid acid catalyst, the high boiling point compound can be decomposed into various constituents, and at the same time, 1,4-butanediol can be converted into tetrahydrofuran. The high boiling point compound contains In the case of 4-hydroxybutyric acid, 4-hydroxybutyric acid can be converted into γ-butyrolactone. It was also found that even if succinic acid and/or 4-hydroxybutyric acid and tetrahydrofuran coexist, high boiling point compounds (ester oligomers) are not generated; even if γ-butyrolactone and 1,4-butanediol coexist, neither This produces high boiling compounds (ester oligomers). The present inventors have accomplished the present invention based on the above findings. That is, the gist of the present invention resides in the following (1) to (15).

(1) A method for decomposing an ester oligomer, wherein an aqueous solution of an ester oligomer containing succinic acid and/or 4-hydroxybutyric acid and 1,4-butanediol as constituents is mixed with Contact with a solid acid catalyst to decompose the ester oligomer into its constituents while simultaneously converting 1,4-butanediol into tetrahydrofuran, and/or in the presence of 4-hydroxybutyric acid as the constituent of the ester oligomer In the case of 4-hydroxybutyric acid is converted to γ-butyrolactone.

(2) A method for decomposing an ester oligomer, wherein an aqueous solution of an ester oligomer containing succinic acid and 1,4-butanediol as constituents is brought into contact with a solid acid catalyst under heating to make the ester oligomer The oligomers decompose into succinic acid and 1,4-butanediol, while converting 1,4-butanediol to tetrahydrofuran.

(3) A method for decomposing ester oligomers, wherein an aqueous solution of ester oligomers containing 4-hydroxybutyric acid and 1,4-butanediol as constituents is contacted with a solid acid catalyst under heating, The ester oligomer is decomposed into 4-hydroxybutyric acid and 1,4-butanediol, and 4-hydroxybutyric acid is converted into γ-butyrolactone at the same time.

(4) The method for decomposing ester oligomers according to any one of the above (1) to (3), wherein the aqueous solution of the ester oligomers is heated at a temperature of 80° C. to 200° C. The solid acid catalyst is contacted for 1 hour to 20 hours.

(5) The method for decomposing an ester oligomer according to any one of (1) to (4) above, wherein the aqueous solution of the ester oligomer is an aqueous solution having a phosphorus concentration of 1 wtppm to 400 wtppm.

(6) The method for decomposing an ester oligomer according to any one of (1) to (5) above, wherein the aqueous solution of the ester oligomer is produced by hydrogenation of a dicarboxylic acid or an acid anhydride to produce a C4 compound An aqueous solution of a high-boiling compound produced as a by-product, or an aqueous solution of a high-boiling compound produced as a by-product when a C4 compound is produced by a dehydrogenation reaction of a diol.

(7) The method for decomposing ester oligomers according to the above (6), wherein the C4 compound is γ-butyrolactone, 1,4-butanediol, tetrahydrofuran, succinic acid and succinic anhydride of at least one compound.

(8) The method for decomposing an ester oligomer according to (6) above, wherein the C4 compound is γ-butyrolactone.

(9) The method for decomposing an ester oligomer according to any one of (1) to (8) above, wherein the solid acid catalyst is a cation exchange resin having a sulfonic acid group.

(10) A method for producing succinic acid, wherein an aqueous solution of an ester oligomer containing succinic acid and 1,4-butanediol as constituents is brought into contact with a solid acid catalyst under heating to oligomerize the ester The product is decomposed into succinic acid and tetrahydrofuran.

(11) A method for producing γ-butyrolactone, wherein an aqueous solution of an ester oligomer containing 4-hydroxybutyric acid and 1,4-butanediol as constituents is brought into contact with a solid acid catalyst under heating , to decompose the ester oligomer into γ-butyrolactone and tetrahydrofuran.

(12) A method for producing a C4 compound, which is a method for producing a C4 compound by hydrogenation of a dicarboxylic acid or an acid anhydride, wherein an aqueous solution containing a high boiling point compound produced as a by-product during the production of the C4 compound is decomposed into succinic acid and tetrahydrofuran, and introducing the resulting succinic acid into the hydrogenation of the dicarboxylic acid or anhydride.

(13) A method for producing a C4 compound, which is a method for producing a C4 compound by hydrogenation of a dicarboxylic acid or an acid anhydride, wherein an aqueous solution containing a high boiling point compound produced as a by-product during the production of the C4 compound is prepared , contact with a solid acid catalyst under heating, decompose the high boiling point compound into succinic acid and tetrahydrofuran, distill and separate the water and tetrahydrofuran in the solution, and introduce the obtained succinic acid aqueous solution into the dicarboxylic acid or anhydride in the hydrogenation reaction.

(14) The method for producing a C4 compound according to (12) or (13) above, wherein the method for producing a C4 compound by hydrogenation of a dicarboxylic acid or an acid anhydride is by using a homogeneous ruthenium complex catalyst , the method for carrying out the hydrogenation reaction of any one compound or any two or more compounds in succinic anhydride, succinic acid and maleic anhydride; or the method for producing a C4 compound through the dehydrogenation reaction of diol is, by using a homogeneous A ruthenium complex catalyst is used to dehydrogenate 1,4-butanediol to produce γ-butyrolactone.

(15) The method for producing a C4 compound according to any one of (12) to (14) above, wherein the aqueous solution containing a high-boiling compound produced as a by-product during the production of the C4 compound is obtained by the following method: The water phase in the system having more than 2 phases: from the reaction solution obtained by the hydrogenation reaction of the dicarboxylic acid or acid anhydride or the reaction solution obtained by the dehydrogenation reaction of the diol, the removal of C4 compounds and the reaction solvent to obtain a catalyst solution containing the high boiling point compound as a by-product, adding water and a non-polar solvent to the catalyst solution for extraction treatment to obtain the system having two or more phases.

The present invention can be used in any mode of batch, semi-batch and continuous. Hereinafter, it will be described in detail.

According to the present invention, it is possible to provide a method for decomposing ester oligomers (high-boiling point compounds) containing succinic acid and/or 4-hydroxybutyric acid and 1,4-butanediol as constituents. A method for decomposing high-boiling-point compounds (ester oligomers) produced as by-products in the production method of γ-butyrolactone can further provide a method for producing industrially useful C4 products, especially γ-butyrolactone. Process for the manufacture of lactones.

Description of drawings

FIG. 1 is a schematic diagram of an apparatus for carrying out "hydrogenation of succinic anhydride using trioctylphosphineruthenium-p-toluenesulfonic acid catalyst" in Reference Examples.

Symbol Description

1: Gas-liquid separator 2: Distillation tower

3: Catalyst container 4: Remove the catalyst container

5: New catalyst container 6: Compressor

7: Raw material container 8: Autoclave

10: Exhaust gas 11: Lactone, water

Detailed ways

The method for decomposing ester oligomers of the present invention is characterized in that an aqueous solution of ester oligomers containing succinic acid and/or 4-hydroxybutyric acid and 1,4-butanediol as constituents is mixed with a solid under heating. contact with an acid catalyst to decompose the ester oligomer into its constituents while simultaneously converting 1,4-butanediol into tetrahydrofuran, and/or in the presence of 4-hydroxybutyric acid as a constituent of the ester oligomer case, 4-hydroxybutyric acid is converted to gamma-butyrolactone.

Moreover, following (i)-(iii) can be mentioned as embodiment of this invention.

(i) A method for producing succinic acid, wherein an aqueous solution of an ester oligomer containing succinic acid and 1,4-butanediol as constituents is brought into contact with a solid acid catalyst under heating to oligomerize the ester The product is decomposed into succinic acid and tetrahydrofuran.

(ii) A method for producing γ-butyrolactone, wherein an aqueous solution of an ester oligomer containing 4-hydroxybutyric acid and 1,4-butanediol as constituents is brought into contact with a solid acid catalyst under heating , to decompose the ester oligomer into γ-butyrolactone and tetrahydrofuran.

(iii) A method for producing a C4 compound, which is a method for producing a C4 compound by hydrogenation of a dicarboxylic acid or an acid anhydride, wherein an aqueous solution containing a high boiling point compound produced as a by-product during the production of the C4 compound is decomposed into succinic acid and tetrahydrofuran, and introducing the resulting succinic acid into the hydrogenation of the dicarboxylic acid or anhydride.

"Ester oligomer containing succinic acid and/or 4-hydroxybutyric acid and 1,4-butanediol as constituents" in the present invention means 1,4-butanediol, succinic acid and 4-hydroxybutanediol Butyric acid undergoes dehydration condensation to produce ester oligomers cross-linked by ester bonds, or a mixture of 1,4-butanediol, succinic acid and 4-hydroxybutyric acid. The ester oligomer is composed of structural units derived from 1,4-butanediol, succinic acid, and 4-hydroxybutyric acid, and it is preferable that the ester oligomer is composed of 2 or more and 20 or less of the above structural units. If the number of these constituent units is only one, that is, monomers such as 1,4-butanediol, succinic acid or 4-hydroxybutyric acid, there is no need to decompose; if the number of these constituent units is too large, use The reaction conditions for the decomposition become severe, and the decomposition process becomes uneconomical due to deterioration of the ion exchange resin due to high-temperature reaction, expansion of the reactor, and extension of the reaction time. In addition, it is considered that a high boiling point compound having more than 20 constituent units is not produced in a normal hydrogenation reaction, dehydrogenation reaction, or the like. The structural units constituting the ester oligomer are two or more types, usually two to four types.

Examples of these ester oligomers include high boiling point compounds produced as by-products during the production of C4 compounds, and specifically, the following compound groups. However, it is not limited to these compounds.

Examples of high boiling point compounds include high boiling point compounds produced as by-products in methods for producing C4 compounds, such as producing γ by hydrogenation of succinic acid or succinic anhydride using a solid catalyst. - a process for butyrolactone, 1,4-butanediol or tetrahydrofuran; a process for the manufacture of gamma-butyrolactone, 1,4-butanediol, tetrahydrofuran, succinic acid or succinic anhydride by hydrogenation of maleic anhydride; Method for producing gamma-butyrolactone by dehydrogenation of 1,4-butanediol; production of gamma-butyrolactone and 1,4-butyrolactone by hydrogenation of succinic acid or succinic anhydride using a homogeneous complex catalyst A method of diol or tetrahydrofuran; a method of producing γ-butyrolactone by a hydrogenation reaction of maleic anhydride or a dehydrogenation reaction of 1,4-butanediol using a homogeneous complex catalyst; and the like.

The production method of the above-mentioned C4 compound may be any production method in gas phase, liquid phase, solid catalyst or complex catalyst. Examples of the C4 compound include γ-butyrolactone, 1,4-butanediol, tetrahydrofuran, furan, dihydrofuran, succinic acid or succinic anhydride, preferably γ-butyrolactone, 1,4-butanediol, Tetrahydrofuran, succinic acid or succinic anhydride, particularly preferably gamma-butyrolactone. The present invention can be applied to all the above-mentioned production methods of the C4 compound, however, it is preferably used in the following production method: production of γ-butyrolactone or 1,4 by hydrogenation of succinic acid or succinic anhydride using a solid catalyst - Method for butanediol, method for producing γ-butyrolactone or 1,4-butanediol by hydrogenation of maleic anhydride, method for producing γ-butyrolactone by dehydrogenation of 1,4-butanediol Method, method for producing γ-butyrolactone by hydrogenation of succinic acid or succinic anhydride using a homogeneous complex catalyst, method for producing γ-butyrolactone by hydrogenation of maleic anhydride, production of 1,4- The method for butanediol and the method for producing γ-butyrolactone by the dehydrogenation reaction of 1,4-butanediol are particularly preferably used in the following production method with the generation of by-products: from amber using a solid catalyst A method for producing γ-butyrolactone by hydrogenation of acid or succinic anhydride, and a method for producing γ-butyrolactone by hydrogenation of succinic acid or succinic anhydride using a homogeneous complex catalyst.

Next, the above reaction will be described. Regardless of the product of these reactions, these reactions can be divided into four categories, namely, 1) hydrogenation reactions using a solid catalyst; 2) dehydrogenation reactions using a solid catalyst; 3) hydrogenation reactions using a complex catalyst; and 4) a dehydrogenation reaction using a complex catalyst. These four types of responses are described one by one. For the use of solid catalysts for hydrogenation reactions, preferably copper-chromium, copper-zinc, copper-aluminum, or copper-metal oxide solid catalysts, adopting reaction conditions under liquid phase or under gas phase, are particularly suitable for The hydrogenation reaction of maleic anhydride, maleic acid, succinic anhydride, succinic acid or γ-butyrolactone, the products obtained are succinic anhydride, succinic acid, γ-butyrolactone or 1,4-butanediol, etc. This type of reaction is usually carried out at a hydrogen pressure of 1 MPa to 10 MPa, and a reaction temperature of 150°C to 300°C. Purify the product from the reacted solution by distillation, crystallization or solvent absorption, etc. In addition, for the dehydrogenation reaction that has used solid catalyst, also preferably the solid catalyst of copper-chromium, copper-zinc, copper-aluminum or copper-metal oxide class, usually adopts the reaction condition under gas phase, is applicable to by A method for producing γ-butyrolactone by dehydrogenating 1,4-butanediol. This type of reaction is usually carried out at a pressure of 0.01 MPa to 1 MPa under an atmosphere of hydrogen gas which is a by-product of the reaction. The reaction temperature is 150°C-300°C, and the product is purified from the reacted solution by distillation. For the hydrogenation reaction using a complex catalyst, a ruthenium complex catalyst is preferred, and usually the catalyst contains a phosphorus compound as a ligand. This type of reaction adopts liquid-phase reaction conditions, and is especially suitable for the method of producing γ-butyrolactone by hydrogenation of succinic anhydride or succinic acid. This type of reaction is carried out under the conditions of a reaction temperature of 100° C. to 250° C. and a hydrogen pressure of 1 MPa to 5 MPa. Purify the product from the reacted solution by distillation, crystallization or solvent absorption, etc. In addition, for the dehydrogenation reaction using a complex catalyst, a ruthenium complex catalyst is also preferred, and usually this catalyst contains a phosphorus compound as a ligand. This type of reaction adopts liquid-phase reaction conditions, and is especially suitable for the method of producing γ-butyrolactone from the dehydrogenation of 1,4-butanediol. This type of reaction is usually carried out at a pressure of 0.01 MPa to 1 MPa under an atmosphere of hydrogen gas which is a by-product of the reaction. The reaction temperature is 150°C-300°C, and the product is purified from the reacted solution by distillation.

In the process of producing C4 compounds such as γ-butyrolactone, the solution after the reaction contains high boiling point compounds as by-products produced by hydrogenation reaction or dehydrogenation reaction. Examples of the "aqueous solution of high-boiling-point compounds produced as by-products during the production of C4 compounds" in the present invention include aqueous solutions containing such high-boiling-point compounds produced as by-products. Specifically, an aqueous solution obtained by adding water to the reacted solution can be used, or an aqueous solution obtained by removing C4 compounds such as γ-butyrolactone from the reacted solution and having a boiling point lower than that of γ-butyrolactone can be used. A low boiling point compound such as a C4 compound, and an aqueous solution obtained by adding water to a solution after the reaction solvent in the liquid phase reaction, the latter is preferably used.

In the present invention, the ester oligomer "contains two structural units of succinic acid and 1,4-butanediol" or "is an ester oligomer containing succinic acid as a structural unit and 1,4-butanediol A mixture of ester oligomers as constituent units", or "contains three constituent units of succinic acid, 4-hydroxybutyric acid and 1,4-butanediol" or "is an ester oligomer containing succinic acid as constituent units Compounds, mixtures of ester oligomers containing 4-hydroxybutyric acid as constituent units and ester oligomers containing 1,4-butanediol as constituent units”, or “containing 4-hydroxybutyric acid and 1,4- These two structural units of butanediol" or "is a mixture of an ester oligomer containing 4-hydroxybutyric acid as a structural unit and an ester oligomer containing 1,4-butanediol as a structural unit". Each of the above-mentioned ester oligomers may have other structural units.

The present invention can be applied to an aqueous solution containing only one kind of the above-mentioned ester oligomer, or to an aqueous solution containing a plurality of oligomers. As the aqueous solution of the ester oligomer (high boiling point compound) used in the present invention, an aqueous solution containing 1% by weight to 80% by weight of the ester oligomer (high boiling point compound) can be used, preferably an aqueous solution containing 3% by weight % to 30% by weight of the aqueous solution of the ester oligomer (high boiling point compound), particularly preferably an aqueous solution containing 5% by weight to 20% by weight of the above ester oligomer (high boiling point compound). If the content of high boiling point compounds is too small, the hydrolysis efficiency will decrease, which is unfavorable in industry; if the content of high boiling point compounds is too much, the hydrolysis rate will decrease, and at the same time, high boiling point compounds will not completely dissolve in water, forming a solid-liquid mixture , resulting in problems in the manufacturing process such as clogging.

In addition, the water content in the aqueous solution is preferably 10% by weight or more, more preferably 30% by weight to 95% by weight, particularly preferably 50% by weight to 90% by weight. If the water content is too small, the hydrolysis rate will decrease when the ester oligomer (high boiling point compound) contacts with the solid acid catalyst, and problems such as blockage caused by the precipitation of the high boiling point compound will occur in the manufacturing process; if the water content is too much, Then the yield of hydrolyzate per unit volume of the reactor decreases.

In addition, the hydrolysis of the present invention can be carried out without any problem even if other components are contained besides the above-mentioned high-boiling point compound as a by-product. , 4-hydroxybutyric acid or an aqueous solution of the high boiling point compound of γ-butyrolactone. The present invention is also applicable when the mixed esters contain a small amount of alcohols or acids produced as by-products in the production process of γ-butyrolactone. For example, in the production reaction of γ-butyrolactone, a small amount of alcohols and acids produced as by-products refer to alcohols and acids with 2 to 10 carbon atoms, preferably 1-octanol, 2- Octanol, 1-hexanol, 2-hexanol, 1-butanol, 2-butanol, ethanol, methanol, diethylene glycol monomethyl ether, ethylene glycol, diethylene glycol, triethylene glycol monomethyl ether, three Glycol, formic acid, acetic acid, propionic acid or butyric acid, etc. In addition, diethylene glycol monomethyl ether or triethylene glycol monomethyl ether is particularly preferable, and these alcohols or acids may be contained as by-products in an amount of 10 wt. ppm to 5 wt. %. These alcohols or acids are small amounts of by-products generated from reaction solvents, catalyst components, γ-butyrolactone, 1,4-butanediol, succinic acid, succinic anhydride, maleic anhydride, and the like. Moreover, when using the manufacturing method of the complex catalyst which uses a phosphorus compound as a ligand, the aqueous solution of this ester oligomer may contain a phosphorus compound. As a result of intensive studies, the inventors of the present invention have found that phosphorus compounds can cause deterioration of solid acid catalysts. Therefore, it is preferable to contain phosphorus compounds at as low a concentration as possible in the aqueous solution of the ester oligomer. That is, the concentration of phosphorus atoms is preferably 0 wt. ppm to 1 wt. %, particularly preferably 1 wt. ppm to 200 wt. ppm.

In the present invention, a solid acid catalyst is used to decompose an ester oligomer (high boiling point compound) containing succinic acid and/or 4-hydroxybutyric acid and 1,4-butanediol as constituents into each constituent, and at the same time 1,4-butanediol is converted to tetrahydrofuran, and/or, in the case of containing 4-hydroxybutyric acid as a constituent of the ester oligomer, 4-hydroxybutyric acid is converted to γ-butyrolactone. Examples of the solid acid catalyst used here include cation exchange resins, metal oxides, zeolites, activated clay, and metal sulfates, among which cation exchange resins are preferred. As the cation exchange resin, a strongly acidic cation exchange resin is preferable, and a strongly acidic cation exchange resin having a sulfonic acid group is particularly preferable. For example, a sulfonated styrene-divinylbenzene copolymer can be used, but it is not particularly limited to the sulfonated styrene-divinylbenzene copolymer, and a commercially available product can also be used. In addition, the structure type of the cation exchange resin is not particularly limited, and any one of gel type, MR (macroreticular) type, porous type, and highly porous type can also be used.

In order to use a solid acid catalyst, ester oligomers (high boiling point compounds) containing succinic acid and/or 4-hydroxybutyric acid and 1,4-butanediol as constituents are decomposed into constituents, and 1,4 - butanediol into tetrahydrofuran, and/or in the case of 4-hydroxybutyric acid as a constituent of the ester oligomer, 4-hydroxybutyric acid into γ-butyrolactone, under heating The ester oligomer is contacted with the solid acid catalyst, and the heating temperature (reaction temperature) is preferably above 50°C, more preferably above 60°C, especially preferably above 80°C, and preferably below 300°C, more preferably below 200°C , especially preferably below 150°C. When the reaction temperature is too low, the hydrolysis rate slows down, resulting in a decrease in reaction efficiency; and when the reaction temperature is too high, the deterioration of solid acid catalysts such as ion exchange resins is accelerated.

The contact time with the solid acid catalyst and the residence time in the reactor in the case of a continuous system are preferably 10 minutes or more, more preferably 1 hour or more, particularly preferably 2 hours or more, and preferably 100 hours or less, more preferably 40 hours or less, particularly preferably 20 hours or less. If the residence time in the reactor is too short, the hydrolysis will not proceed completely, and if the residence time in the reactor is too long, the reactor will expand unnecessarily and the efficiency of the reaction process will be low.

Using a solid acid catalyst, an ester oligomer containing succinic acid and/or 4-hydroxybutyric acid and 1,4-butanediol as constituents is decomposed into its respective constituents, while simultaneously converting 1,4-butanediol into Tetrahydrofuran, and/or, in the case of containing 4-hydroxybutyric acid as a constituent of the ester oligomer, converts 4-hydroxybutyric acid into γ-butyrolactone.

If 1,4-butanediol coexists with succinic acid and/or 4-hydroxybutyric acid, ester oligomers are formed, but even if tetrahydrofuran coexists with succinic acid and/or 4-hydroxybutyric acid, ester oligomers are not formed. polymer, therefore, if 1,4-butanediol is converted to tetrahydrofuran, a state capable of decomposing ester oligomers can be maintained. If 1,4-butanediol is converted to tetrahydrofuran, the amount of succinic acid and/or 4-hydroxybutyric acid corresponding to the amount of converted 1,4-butanediol does not form ester oligomers and can be separated. That is, in the present invention, even if only a small amount of 1,4-butanediol is converted into tetrahydrofuran, an amount of ester oligomer corresponding to the converted amount can be decomposed, and each component can also be separated. The ratio of 1,4-butanediol converted to tetrahydrofuran is usually 10% or more, preferably 30% or more, more preferably 60% or more. If the ratio of 1,4-butanediol converted to tetrahydrofuran is too small, it will be difficult to separate 1,4-butanediol from other components such as succinic acid. The higher the conversion ratio, the larger the decomposition ratio, so a higher conversion ratio is preferred. However, from the perspective of economical considerations such as the expansion of the reactor, the increase in the amount of catalyst, or the situation where the ratio of the constituent components is seriously unbalanced, it is not required to convert 1,4-butanediol into tetrahydrofuran in a large amount, and the conversion ratio can be Below 30%.

In addition, since the coexistence of γ-butyrolactone and 1,4-butanediol does not form ester oligomers, if 4-hydroxybutyric acid is converted into γ-butyrolactone, it can maintain the ability to make ester oligomers state of decomposition. When 4-hydroxybutyric acid is converted to γ-butyrolactone, the amount of 1,4-butanediol corresponding to the amount of converted 4-hydroxybutyric acid can be separated without forming ester oligomers. That is, in the present invention, even if only a small amount of 4-hydroxybutyric acid is converted to γ-butyrolactone, an amount equivalent to the converted amount of ester oligomers can be decomposed and the components can also be separated. The conversion ratio of 4-hydroxybutyric acid to γ-butyrolactone is usually 10% or more, preferably 30% or more, more preferably 60% or more. If the ratio of 4-hydroxybutyric acid converted to γ-butyrolactone is too small, it will be difficult to separate 4-hydroxybutyric acid from 1,4-butanediol. The higher the conversion ratio, the larger the decomposition ratio. Therefore, a higher conversion ratio is preferred. However, from the economic aspects such as the expansion of the reactor, the increase of the catalyst amount, or the situation where the ratio of the constituent components is seriously unbalanced, then It is not required to convert 4-hydroxybutyric acid into γ-butyrolactone in a large amount, and the conversion ratio can be below 30%.

Specific examples of the decomposition method of the ester oligomer include the following (a) to (c).

(a) For the case where the ester oligomer contains succinic acid and 1,4-butanediol as constituents, use a solid acid catalyst to hydrolyze the ester oligomer into succinic acid and 1,4-butanediol, and then , converting 1,4-butanediol to tetrahydrofuran. The conversion ratio of 1,4-butanediol to tetrahydrofuran is usually 30% to 100%, preferably 60% to 100%. If after the above operation, the water and tetrahydrofuran are distilled and separated, succinic acid can be obtained. In the method of producing a C4 compound by the hydrogenation reaction of a dicarboxylic acid or an acid anhydride, the obtained succinic acid is effectively utilized by being introduced into the hydrogenation reaction of a dicarboxylic acid or an acid anhydride. If the ester oligomer containing succinic acid and 1,4-butanediol as constituents is a high-boiling compound produced as a by-product in the process for producing C4 compounds by the hydrogenation reaction of dicarboxylic acids or acid anhydrides, then by obtaining The introduction of succinic acid into the hydrogenation reaction of dicarboxylic acid or anhydride can improve the yield of hydrogenation reaction.

Water and tetrahydrofuran were separated from succinic acid by distillation. The distillation used therein can remove water and tetrahydrofuran by simple distillation or multistage distillation under normal pressure or reduced pressure. At this time, the component containing a lot of tetrahydrofuran can be removed from the top of the column, and the water containing almost no tetrahydrofuran can be removed from the side stream. Preferably, the top pressure is 40mmHg-760mmHg, more preferably 200mmHg-760mmHg, and the number of trays is 1-40, preferably 1-20, particularly preferably 1-10.

(b) For the case where the ester oligomer contains succinic acid, 4-hydroxybutyric acid and 1,4-butanediol as constituents, use a solid acid catalyst to hydrolyze the ester oligomer into succinic acid, 4-hydroxybutyric acid Butyric acid and 1,4-butanediol, and further, 4-hydroxybutyric acid is converted into γ-butyrolactone, and 1,4-butanediol is converted into tetrahydrofuran, respectively. For the conversion ratio of 4-hydroxybutyric acid to γ-butyrolactone, it is usually 30% to 100%, preferably 60% to 100%; for the conversion ratio of 1,4-butanediol to THF, it is usually 30% ~ 100%, preferably 60% to 100%. If the water, tetrahydrofuran and γ-butyrolactone are separated by distillation after the above operation, succinic acid can be obtained. In the method of producing a C4 compound by the hydrogenation reaction of a dicarboxylic acid or an acid anhydride, the obtained succinic acid can be effectively utilized by being introduced into the hydrogenation reaction of a dicarboxylic acid or an acid anhydride. Alternatively, if the water and tetrahydrofuran are separated by distillation, succinic acid containing gamma-butyrolactone can be obtained. If the ester oligomer containing succinic acid, 4-hydroxybutyric acid, and 1,4-butanediol as constituents is a high-boiling point product produced as a by-product in a process for producing C4 compounds by hydrogenation of dicarboxylic acids or acid anhydrides Compound, then by introducing the obtained succinic acid into the hydrogenation reaction of dicarboxylic acid or acid anhydride, the yield of hydrogenation reaction can be improved.

Water, tetrahydrofuran and gamma-butyrolactone were separated from succinic acid by distillation. The distillation adopted therein can remove water, tetrahydrofuran and γ-butyrolactone by simple distillation or multistage distillation under normal pressure or reduced pressure. At this time, the component containing more tetrahydrofuran can be removed from the top of the tower, the water almost free of tetrahydrofuran can be removed from the first side stream closer to the top of the tower, and the γ-butylene can be removed from the second side stream closer to the bottom of the tower. ester. Alternatively, it is also possible to obtain γ-butyrolactone-containing succinic acid by removing a component containing a large amount of tetrahydrofuran from the top of the column, and removing water containing almost no tetrahydrofuran from a side stream. Preferably, the top pressure is 40mmHg-760mmHg, more preferably 200mmHg-760mmHg, and the number of trays is 1-40, preferably 1-20, particularly preferably 1-10.

(c) In the case where the ester oligomer contains 4-hydroxybutyric acid and 1,4-butanediol as constituents, the ester oligomer is hydrolyzed into 4-hydroxybutyric acid and 1,4-butanediol using a solid acid catalyst. -butanediol, and further, 4-hydroxybutyric acid is partially converted into γ-butyrolactone, and 1,4-butanediol is partially converted into tetrahydrofuran, respectively. For the conversion ratio of 4-hydroxybutyric acid to γ-butyrolactone, it is usually 30% to 100%, preferably 60% to 100%; for the conversion ratio of 1,4-butanediol to THF, it is usually 0% ~ 100%, preferably 0% to 50%. If the water, tetrahydrofuran and γ-butyrolactone are separated by distillation after the above operation, 1,4-butanediol can be obtained. In the method for producing C4 compounds by the dehydrogenation reaction of 1,4-butanediol, especially in the method for producing γ-butyrolactone by the dehydrogenation reaction of 1,4-butanediol, the obtained 1,4 -Butanediol can be effectively utilized by being introduced into the dehydrogenation reaction of 1,4-butanediol. If the ester oligomer containing 4-hydroxybutyric acid and 1,4-butanediol as constituents is a high-boiling compound produced as a by-product in the process for producing C4 compounds by dehydrogenation of diols, then by adding The obtained 1,4-butanediol is introduced into the dehydrogenation reaction, and the yield of the dehydrogenation reaction can be improved.

Water, tetrahydrofuran and gamma-butyrolactone are separated from 1,4-butanediol by distillation. The distillation adopted therein can remove water, tetrahydrofuran and γ-butyrolactone by simple distillation or multistage distillation under normal pressure or reduced pressure. At this time, the component containing more tetrahydrofuran can be removed from the top of the tower, the water almost free of tetrahydrofuran can be removed from the first side closer to the top of the tower, and the γ-butylene can be removed from the second side closer to the bottom of the tower. ester. Alternatively, a component containing a large amount of tetrahydrofuran may be removed from the top of the column, and water containing almost no tetrahydrofuran may be removed from the side retention portion to obtain 1,4-butanediol containing γ-butyrolactone. Preferably, the top pressure is 40mmHg-760mmHg, more preferably 200mmHg-760mmHg, and the number of trays is 1-40, preferably 1-20, particularly preferably 1-10.

In addition, as the reactor system, a batch system or a continuous system can be used, and a complete mixing type reactor and a tubular type reactor can also be used. A continuous tubular reactor is preferred. In addition, from the viewpoint of avoiding clogging caused by solids in a reactor filled with a solid ion exchange resin, it is preferable that the aqueous solution of the high-boiling compound produced as a by-product be uniform before being introduced into the reactor. The liquid phase of the raw material tank is preferably heated and kept at a temperature above 40°C and below 200°C, more preferably above 60°C and below 150°C.

In addition, in the present invention, the 1,4-butanediol ring produced by the hydrolysis of ester oligomers (high boiling point compounds produced as by-products) must be decomposed in a reactor having a solid acid catalyst (ion exchange resin). Dehydration forms tetrahydrofuran, and part or all of the generated 1,4-butanediol is converted into tetrahydrofuran. Similarly, 4-hydroxybutyric acid produced by hydrolysis of ester oligomers (high boiling point compounds produced as a by-product) is converted into γ-butyrolactone. In this case, the cyclodehydration of 1,4-butanediol to tetrahydrofuran and the cyclodehydration of 4-hydroxybutyric acid to gamma-butyrolactone can also be carried out in the same reactor as the hydrolysis; or Make 1,4-butanediol and 4-hydroxybutyric acid pass through one or more reactors, and form tetrahydrofuran and γ-butyrolactone through cyclodehydration in multistage reactors. In addition, for the solid acid catalyst that makes 1,4-butanediol and 4-hydroxybutyric acid generated by the hydrolysis of high boiling point compounds cyclodehydrate to form tetrahydrofuran and γ-butyrolactone respectively, it is preferably an ion exchange resin, more preferably Strongly acidic cation exchange resin. For example, a sulfonated styrene-divinylbenzene copolymer can be used, but it is not particularly limited to the sulfonated styrene-divinylbenzene copolymer, and a commercially available product can also be used. In addition, the structure type of the ion exchange resin is not particularly limited, and any one of gel type, MR (macroreticular) type, porous type, and highly porous type may be used.

In the reaction using a cation exchange resin having a sulfonic acid group, etc., sometimes sulfate ions and other ionic substances from the acid are eluted into the reactor effluent, and the ionic substances from the acid may be released during the reaction. adverse effects such as corrosion. Therefore, the tube filled with the anion exchange resin may be provided after the reactor filled with the cation exchange resin. The anion exchange resin is not particularly limited, and a commercially available one can also be used. In addition, the structure type of the anion exchange resin is not particularly limited, and any one of gel type, MR (macroreticular) type, porous type, and highly porous type can be used.

The method for producing a C4 compound of the present invention is particularly preferably a method for producing a C4 compound by hydrogenation of succinic acid or succinic anhydride using a homogeneous ruthenium complex catalyst. The supply form of ruthenium as a catalyst in this production method is not particularly limited, and a metal or a ruthenium compound can be used. As the ruthenium compound used in the present invention, for example, oxides, hydroxides, salts of inorganic acids, salts of organic acids, or complexes can be used. Specifically, ruthenium dioxide, ruthenium tetroxide, ruthenium(II) hydroxide, ruthenium chloride, ruthenium bromide, ruthenium iodide, ruthenium nitrate, ruthenium acetate, ruthenium triacetylacetonate, sodium hexachlororuthenate, etc. , preferably ruthenium chloride, ruthenium triacetylacetonate or ruthenium acetate.

In addition, as organophosphorus compounds, organophosphorus compounds containing at least one aryl group such as triphenylphosphine, diphenylmethanephosphine or dimethylphenylphosphine and their decomposition products can be used, preferably trialkylphosphine, more preferably Trialkylphosphorus composed of primary alkyl groups and their decomposition products.

Examples of suitable organophosphorus compounds include: tridecylphosphine, trinonylphosphine, trioctylphosphine, triheptylphosphine, trihexylphosphine, tripentylphosphine, tributylphosphine, tripropylphosphine Phosphine, triethylphosphine, trimethylphosphine, dimethyloctylphosphine, dioctylmethylphosphine, dimethylheptylphosphine, diheptylmethylphosphine, dimethylhexylphosphine, dihexylmethylphosphine, di Methylbutylphosphine, dibutylmethylphosphine, tricyclohexylphosphine, tribenzylphosphine, dimethylcyclohexylphosphine, dicyclohexylmethylphosphine, 1,2-bis(dimethylphosphino)ethane, 1, 3-bis(dimethylphosphino)propane, 1,4-bis(dimethylphosphino)butane, 1,2-bis(dioctylphosphino)ethane, 1,3-bis(dioctyl phosphino)propane, 1,4-bis(dioctylphosphino)butane, 1,2-bis(dihexylphosphino)ethane, 1,3-bis(dihexylphosphino)propane, 1, 4-bis(dihexylphosphino)butane, 1,2-bis(dibutylphosphino)ethane, 1,3-bis(dibutylphosphino)propane, 1,4-bis(dibutyl Phosphino)butane, 1,3-dimethylphosphorinane, 1,4-dimethylphosphorinane, 8-methyl-8-phosphabicyclo[3.2.1]octane, Monodentate, polydentate and cyclic alkylphosphine compounds such as 4-methyl-4-phosphatetracyclooctane or 1-methylphosphorane, and alkylphosphine compounds with substituents on the alkyl group. The alkyl group in the trialkylphosphorus used in this reaction can be n-alkyl, iso-alkyl, and a mixture of the two. These phosphine ligands are used in an amount of 0.1 mol to 1000 mol, preferably 1 mol to 100 mol, particularly preferably 1 mol to 10 mol, relative to 1 mol of ruthenium metal.

In addition, not only organic phosphines with trialkylphosphine or aromatic substituents, but also other coordinating organic compounds with phosphorus atoms can be used as ligands, for example, phosphite, phosphine, etc. salt, phosphine oxide, aminophosphine or phosphinic acid, etc.

In addition, the ruthenium complex catalyst of the present invention can also be used in the reaction in the form of a cationic complex using the conjugate base of an acid with pKa less than 2, and the use of the conjugate base can improve the activity and stability of the catalyst. Several aspects are valid.

As the conjugate base of an acid with a pKa less than 2, as long as the conjugate base can be formed during the preparation of the catalyst or in the reaction system, as the supply form of the conjugate base, Browns with a pKa less than 2 can be used. Taide acid or its various salts, etc. Specifically, inorganic acids such as nitric acid, perchloric acid, fluoroboric acid, fluorophosphoric acid, or fluorosulfonic acid, such as Bronsted acids, or trichloroacetic acid, dichloroacetic acid, trifluoroacetic acid, and dodecylsulfonic acid , octadecylsulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, tetrakis (pentafluorophenyl) boric acid, or sulfonated styrene-divinylbenzene copolymer and other organic acids Browns Taide's acid, or alkali metal salts, alkaline earth metal salts, ammonium salts or silver salts of these acids, etc.

In addition, the ruthenium complex catalyst of the present invention may also be added in the form of an acid derivative, which is considered to be generated from the conjugate base of the above-mentioned acid in the reaction system. The same effect can be expected even if it is added to the reaction system in the form of, for example, an acid halide, acid anhydride, ester, or amide.

These acids or their salts are used in an amount of 0 mol to 1000 mol, preferably 0 mol to 100 mol, particularly preferably 0 mol to 10 mol, based on ruthenium metal.

The manufacture method of gamma-butyrolactone of the present invention is particularly preferably carried out under solvent-free conditions, that is, the reaction raw materials and the product itself are used as solvents, or the high-boiling point compounds generated as by-products are used as solvents, but the reaction can also be used Solvents other than raw materials. For example, ethers such as diethyl ether, anisole, tetrahydrofuran, ethylene glycol dimethyl ether or dioxane, alcohols such as methanol, ethanol, n-butanol, benzyl alcohol, phenol, ethylene glycol or diethylene glycol, formic acid , acetic acid, propionic acid or toluic acid and other carboxylic acids, methyl acetate, butyl acetate or benzyl benzoate and other esters, benzene, toluene, ethylbenzene or tetralin and other aromatic hydrocarbons, n-hexane, n-octane Or aliphatic hydrocarbons such as cyclohexane, halogenated hydrocarbons such as dichloromethane, trichloroethane or chlorobenzene, nitro compounds such as nitromethane or nitrobenzene, N,N-dimethylformamide, N,N -Carboxylic acid amides such as dimethylacetamide or N-methylpyrrolidone, other amides such as hexamethylphosphoric triamide, urea such as N,N-dimethylimidazolidinone, sulfones such as dimethyl sulfone, Sulfoxides such as dimethyl sulfoxide, lactones such as γ-butyrolactone or caprolactone, polyethers such as tetraglyme or triglyme, or dimethyl carbonate or ethylene carbonate Carbonates such as esters, etc., ethers, polyethers, and γ-butyrolactone as a reaction raw material and product are preferable. Usually, the reaction temperature is 20°C to 350°C, preferably 100°C to 250°C, more preferably 150°C to 220°C. The reaction can be carried out batchwise or continuously.

In addition, in the present invention, γ-butyrolactone can also be removed from a reaction solution containing γ-butyrolactone and a high boiling point compound produced as a by-product (reaction solution after hydrogenation reaction for producing γ-butyrolactone) And reaction solvent, to the catalyst solution obtained, adopt non-polar solvents such as heptane and water to carry out extraction treatment, make this catalyst solution separate into the non-polar solvent phase that contains more ruthenium catalyst and contain more described high boiling point compound The aqueous phase is transported to the reactor containing the cation exchange resin. In addition, non-polar solvents such as heptane and water can also be used to extract the catalyst solution obtained after removing γ-butyrolactone and the reaction solvent, so that the catalyst solution can be separated into three phases, i.e. non-polar solvent phase, A water phase, and an oil phase insoluble in nonpolar solvents and water, and the water phase is sent to a reactor filled with ion exchange resins.

Examples of the nonpolar solvent used here include aliphatic hydrocarbon compounds, alicyclic hydrocarbon compounds, aromatic hydrocarbon compounds, and the like. In addition, these nonpolar solvents may have a substituent. Specific examples include: pentane, hexane, heptane, octane, nonane, decane, cyclopentane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, diethylbenzene or cumene, etc., particularly preferably an aliphatic hydrocarbon compound having 5 to 8 carbon atoms such as pentane, hexane, heptane or octane.

The weight ratio of the catalyst solution/water/non-polar solvent used in the above extraction treatment is 1/0.2˜10/0.2˜10. In addition, the extraction treatment temperature is usually 20°C to 150°C, preferably 40°C to 100°C. However, in order to reduce the phosphorus concentration in the aqueous phase, it is necessary to set the treatment temperature to 70°C or lower and 50°C or higher. The extraction time is 10 minutes to 5 hours, preferably 30 minutes to 3 hours. In addition, depending on the composition of the catalyst solution, extraction and separation using a non-polar solvent and water may separate into two phases or separate into three phases. The two phases are non-polar phases containing more ruthenium catalyst A solvent phase and an aqueous phase containing more high-boiling compounds, the three phases are a non-polar solvent phase containing more ruthenium catalysts, an aqueous phase containing more high-boiling compounds, and an oil insoluble in non-polar solvents and water Phase, both cases are possible, the aqueous phase in both cases is the phase containing more high boiling point compounds formed as by-products, and can be hydrolyzed using a reactor filled with ion exchange resins. In addition, in the case of subjecting 1,4-butanediol obtained by hydrolysis to cyclodehydration to form tetrahydrofuran, both the aqueous phase in the above-mentioned 2-phase separation and 3-phase separation can be used.

In addition, in the above "from the reaction liquid containing γ-butyrolactone obtained by hydrogenation and the high boiling point compound produced as a by-product, γ-butyrolactone and the reaction solvent are removed, and a non-polar catalyst solution such as heptane is used for the obtained catalyst solution. The catalyst solution is separated into a non-polar solvent phase containing more ruthenium catalysts and an aqueous phase containing more high-boiling compounds, and the resulting aqueous phase" and "from the hydrogenation reaction Gamma-butyrolactone and the reaction solvent are removed from the reaction solution of the obtained gamma-butyrolactone and the high boiling point compound generated as a by-product, and the obtained catalyst solution is extracted with non-polar solvents such as heptane and water, so that The catalyst solution is separated into three phases, that is, a non-polar solvent phase containing more ruthenium catalysts, an aqueous phase containing more high-boiling compounds, and an oil phase insoluble in non-polar solvents and water. " corresponds to the "aqueous solution of a high boiling point compound produced as a by-product" in the present invention.

Example

Hereinafter, the present invention will be further described in detail through examples, but the present invention is not limited by the following examples unless the gist of the present invention is exceeded. In addition, in the following examples, tetrahydrofuran, 1,4-butanediol, and γ-butyrolactone were analyzed by gas chromatography (manufactured by Shimadzu Corporation, GC-14B) using the internal standard method, and succinic acid was analyzed by liquid chromatography (manufactured by Shimadzu Corporation, column: CA-10S, detector: SPD-10A) was analyzed, and moisture was analyzed by the Karl Fischer method (manufactured by Mitsubishi Chemical Corporation, Mitsubishi Moisture: CA-20). In addition, the high-boiling-point by-products in Reference Examples 1 to 4 are sampled by GPC (GPC column TSKgelG-1000HXL and 2000HXL 7.8φ×300mm manufactured by TOSOH Corporation), and the sampled samples are sampled by LC-MS (instrument: Micromass Q - Tof, analyzed by ESI positive ion, negative ion ionization method) and NMR (manufactured by Varian, Unity Plus400). As a result, it became clear that the high-boiling point by-products in Reference Examples 1 to 4 were a mixture of the following ester oligomers.

Reference example 1

The hydrogenation of succinic anhydride using trioctylphosphineruthenium-p-toluenesulfonic acid catalyst was carried out as follows. The reaction is carried out by a circulation device with a gas-liquid separator 1 and a distillation tower 2 shown in FIG. 1 . In the catalyst vessel 3, 0.056% by weight of tris(acetylacetonate)ruthenium, 0.51% by weight of trioctylphosphine and 0.22% by weight of p-toluenesulfonic acid were dissolved in triglyme, and the Heat treatment at 200° C. for 2 hours, and then, the treated solution was added to a new catalyst container 5 as a feed catalyst solution. The catalyst solution was supplied to the autoclave 8 at a flow rate of 3500 mL/h, and after gas-liquid separation, the catalyst solution was recovered and recycled as the residual liquid of the distillation tower.

On the other hand, hydrogen compressor 6 was used to send 7.9 Nm ³ /h of hydrogen into the autoclave, and the pressure in the autoclave was adjusted to 20 atmospheres. The temperature of the autoclave was raised to 200° C., and a raw material liquid composed of 80% by weight of succinic anhydride and 20% by weight of γ-butyrolactone was continuously supplied at a flow rate of 375 g/h. After the reaction liquid is cooled to 60°C, the gas-liquid separation is carried out under normal pressure, and then the water, γ-butyrolactone and the catalyst solution are separated as products in the distillation tower, and the catalyst solution is recovered to the catalyst container 3 In this process, from the 7th day after the start of the reaction, a part of the catalyst solution recovered in the catalyst container 3 was removed at a flow rate of 29 g/h, and stored in the catalyst container 4 from which it was removed.

The catalyst equivalent to the removed amount was replenished into the autoclave again from the new catalyst container 5 at a flow rate of 29 g/h. The reaction was carried out continuously for 30 days, and a stable result was obtained from the 7th day. The composition of the removed catalyst solution was as follows.

[Table 1]

Succinic anhydride and succinic acid 4% by weight γ-butyrolactone 4% by weight Triglyme 65% by weight High boiling point compounds 26% by weight Ruthenium metal concentration 92ppm

Reference example 2

The removed catalyst solution obtained in Reference Example 1 above was concentrated as follows. 878.1 g of the removed catalyst solution was added to a jacketed reactor equipped with a vacuum distillation device, and triglyme as a solvent was distilled off by vacuum distillation. At this time, the degree of vacuum is controlled within the range of 70 mmHg to 5 mmHg to keep the liquidus temperature below 160°C. After distilling off the solvent, 295.75 g of a concentrated catalyst solution were obtained. The composition of the obtained concentrated catalyst solution was as follows.

[Table 2]

Triglyme 0.3% by weight Succinic anhydride and succinic acid 19.7% by weight High boiling point compounds 80.0% by weight γ-butyrolactone 0.0% by weight

Reference example 3

90.3 g of water and 28.0 g of heptane were added to 39.8 g of the concentrated catalyst solution obtained in Reference Example 2 above, and stirred at 80° C. for 1 hour. When the solution was allowed to stand at 80° C., the solution separated into three phases from above, namely, a heptane phase, a water phase, and an oil phase insoluble in the heptane phase and the water phase. The aqueous phase was separated from these 3 phases to obtain 114.1 g of the aqueous phase. The composition of the aqueous phase is as follows. The following examples were carried out using this aqueous phase. In addition, the results of ICP analysis showed that the phosphorus concentration in this aqueous phase was 498 wtppm.

[table 3]

Moisture 72.8% by weight Succinic acid and succinic anhydride 9.0% by weight High boiling point compounds 18.2% by weight 1,4-Butanediol 0.0% by weight γ-butyrolactone 0.0% by weight Tetrahydrofuran 0.0% by weight

Reference example 4

86.5 g of water and 28.0 g of heptane were added to 39.8 g of the concentrated catalyst solution obtained in Reference Example 2 above, stirred at 80° C. for 1 hour, then cooled, and the solution was left to stand at 65° C. for 1 hour. As a result, the solution separated into three phases from above, namely, a heptane phase, a water phase, and an oil phase insoluble in the heptane phase and the water phase. The aqueous phase was separated from these 3 phases to obtain 113.2 g of the aqueous phase. The composition of the aqueous phase is as follows. The following examples were carried out using this aqueous phase. In addition, the results of ICP analysis showed that the phosphorus concentration in the aqueous phase was 59 ppm by weight.

[Table 4]

Moisture 71.5% by weight Succinic acid and succinic anhydride 6.5% by weight High boiling point compounds 21.9% by weight 1,4-Butanediol 0.0% by weight γ-butyrolactone 0.1% by weight Tetrahydrofuran 0.0% by weight

Example 1

80 mL of an ion exchange resin (manufactured by Mitsubishi Chemical Corporation, SK1B-H) was filled in an 80 mL stainless steel reaction tube (inner diameter 10 mm), and the aqueous phase (high boiling point compound) obtained in Reference Example 3 diluted to 2 times its weight with desalted water was 9.1% by weight) was passed through the reaction tube at 100° C. at 10 mL/h (residence time 8 hours). The reaction tube was heated to 100°C with a heater. Table 5 shows the composition of the effluent from the reaction tube as a result of analysis.

Example 2

The aqueous phase obtained from Reference Example 3 (9.1% by weight of high boiling point compounds) diluted to 2 times the weight with desalinated water was passed through the reaction tube at 20 mL/h at 100° C. (residence time: 4 hours), except Other than that, it is the same as in Example 1. Table 5 shows the composition of the effluent from the reaction tube as a result of analysis.

Example 3

The aqueous phase obtained in Reference Example 3 (9.1% by weight of high boilers) diluted to 2 times the weight with desalinated water was passed through the reaction tube at 110° C. at 10 mL/h (residence time: 8 hours), and, The heating temperature of the reaction tube was the same as in Example 1 except that the heating temperature was set at 110°C. Table 5 shows the composition of the effluent from the reaction tube as a result of analysis.

Example 4

The aqueous phase obtained in Reference Example 3 (9.1% by weight of high boiling point compounds) diluted to 2 times the weight with desalinated water was passed through the reaction tube at 80° C. at 10 mL/h (residence time: 8 hours), and, The heating temperature of the reaction tube was the same as in Example 1 except that the heating temperature was set to 80°C. Table 5 shows the composition of the effluent from the reaction tube as a result of analysis.

Example 5

In a glass flask with a capacity of 50 mL, a stirring bar, 5.0 g of the aqueous phase obtained in Reference Example 3 (19.2% by weight of a high boiling point compound) and 2.1 g of ion exchange resin (manufactured by Mitsubishi Chemical Corporation, SK1B-H) were put into, It was heated and stirred at 100° C. for 5 hours. The results of analysis of the reaction liquid showed that 39.1% by weight of the high boiling point compound was converted into succinic acid and succinic anhydride, 12.3% by weight of the high boiling point compound was converted into 1,4-butanediol, and 2.5% by weight of the high boiling point compound was converted into tetrahydrofuran .

Example 6

In a glass flask with a capacity of 50 mL, a stirring bar, 2.0 g of the aqueous phase obtained in Reference Example 3 (19.2% by weight of high boiling point compounds), 3.1 g of desalted water and 2.1 g of ion exchange resin (manufactured by Mitsubishi Chemical Corporation, SK1B-H), heated and stirred at 100°C for 5 hours. The analysis results of the reaction liquid showed that 52.6% by weight of the high boiling point compound was converted into succinic acid and succinic anhydride, 15.8% by weight of the high boiling point compound was converted into 1,4-butanediol, and 1.5% by weight of the high boiling point compound was converted into tetrahydrofuran .

Example 7

80 mL of an ion exchange resin (manufactured by Mitsubishi Chemical Corporation, SK1B-H) was filled in an 80 mL stainless steel reaction tube (inner diameter 10 mm), and the aqueous phase obtained in Reference Example 3 (19.2 wt. %) through the reaction tube at 100° C. at 20 mL/h (residence time 8 hours). The reaction tube was heated to 100°C with a heater. Table 5 shows the composition of the effluent from the reaction tube as a result of analysis.

Example 8

80 mL of an ion exchange resin (manufactured by Mitsubishi Chemical Corporation, SK1B-H) was filled in an 80 mL stainless steel reaction tube (inner diameter 10 mm), and the aqueous phase obtained in Reference Example 4 (the high boiling point compound was 21.9 wt. %, phosphorus concentration of 59 wtppm) was passed through the reaction tube at 110° C. at 10 mL/h for 400 hours (residence time was 8 hours). The reaction tube was heated to 110°C with a heater. As a result of analysis of the effluent from the reaction tube, the amount of succinic acid produced after 400 hours was 99.8% (ratio to the amount of succinic acid produced after 8 hours) compared with that after 8 hours, confirming that the activity did not decrease.

Comparative example 1

Except not using an ion exchange resin, it is the same as Example 6. Analysis results of the reaction liquid showed that 2% by weight of the high boiling point compound was converted into succinic acid and succinic anhydride, and 1% by weight of the high boiling point compound was converted into 1,4-butanediol. Tetrahydrofuran was not formed.

Comparative example 2

Except not using an ion exchange resin, it is the same as Example 4. Table 5 shows the composition of the effluent from the reaction tube as a result of analysis.

Example 9

80 mL of an ion exchange resin (manufactured by Mitsubishi Chemical Corporation, SK1B-H) was filled in an 80 mL stainless steel reaction tube (inner diameter 10 mm), and the aqueous phase obtained in Reference Example 3 (the high boiling point compound was 18.2 wt. %, phosphorus concentration of 498 wtppm) was passed through the reaction tube at 110° C. at 10 mL/h for 400 hours (residence time was 8 hours). The reaction tube was heated to 110°C with a heater. As a result of the analysis of the effluent from the reaction tube, the amount of succinic acid produced after 400 hours was reduced to 85.1% (the ratio relative to the amount of succinic acid produced after 8 hours) compared with that after 8 hours.

[table 5]

Industrial Applicability

According to the present invention, high boiling point compounds produced as by-products in the production of C4 product groups such as γ-butyrolactone can be decomposed to regenerate raw materials. Therefore, the present invention is an industrially useful method with higher efficiency. , can be widely used in the method of manufacturing C4 product group.

In addition, the entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2004-299577 filed on October 14, 2004 are incorporated herein by reference and incorporated in the contents of the specification of the present invention.

Claims (9)

1. the decomposition method of an ester oligomer wherein, will contain succsinic acid and/or 4 hydroxybutyric acid and 1; The 4-butyleneglycol contacts with solid acid catalyst under heating as the aqueous solution of the ester oligomer of constituent, makes this ester oligomer resolve into each constituent; With 1, the 4-butyleneglycol is converted into THF simultaneously, and/or is containing under the situation of 4 hydroxybutyric acid as the constituent of said ester oligomer; 4 hydroxybutyric acid is converted into gamma-butyrolactone; Wherein, the aqueous solution of said ester oligomer is that phosphorus concentration is the aqueous solution of 1 ppm by weight～400 ppm by weight, and said solid acid catalyst is to have sulfonic Zeo-karb.

2. the decomposition method of an ester oligomer wherein, will contain succsinic acid and 1; The 4-butyleneglycol contacts with solid acid catalyst under heating as the aqueous solution of the ester oligomer of constituent, makes this ester oligomer resolve into succsinic acid and 1; The 4-butyleneglycol, simultaneously with 1, the 4-butyleneglycol is converted into THF; Wherein, the aqueous solution of said ester oligomer is that phosphorus concentration is the aqueous solution of 1 ppm by weight～400 ppm by weight, and said solid acid catalyst is to have sulfonic Zeo-karb.

3. the decomposition method of an ester oligomer wherein, will contain 4 hydroxybutyric acid and 1; The 4-butyleneglycol contacts with solid acid catalyst under heating as the aqueous solution of the ester oligomer of constituent, makes this ester oligomer resolve into 4 hydroxybutyric acid and 1; The 4-butyleneglycol is converted into gamma-butyrolactone with 4 hydroxybutyric acid simultaneously, wherein; The aqueous solution of said ester oligomer is that phosphorus concentration is the aqueous solution of 1 ppm by weight～400 ppm by weight, and said solid acid catalyst is to have sulfonic Zeo-karb.

4. according to the decomposition method of any described ester oligomer of claim 1～3, wherein, the aqueous solution of said ester oligomer is under 80 ℃～200 ℃ in Heating temperature, contacts 1 hour with said solid acid catalyst～20 hours.

5. according to the decomposition method of any described ester oligomer of claim 1～3; Wherein, The aqueous solution of said ester oligomer is the aqueous solution of the higher-boiling compound that generates as by product when making the C4 compound by the hydrogenation of dicarboxylicacid or acid anhydrides, or the aqueous solution of the higher-boiling compound that generates as by product when making the C4 compound by the dehydrogenation reaction of glycol.

6. the decomposition method of ester oligomer according to claim 5 is characterized in that, said C4 compound is a gamma-butyrolactone, 1, at least a compound in 4-butyleneglycol, THF, succsinic acid and the succinyl oxide.

7. the decomposition method of ester oligomer according to claim 5 is characterized in that, said C4 compound is a gamma-butyrolactone.

8. the method for manufacture of a succsinic acid; Wherein, will contain succsinic acid and 1, the 4-butyleneglycol is as the aqueous solution of the ester oligomer of constituent; Under heating, contact with solid acid catalyst; Make this ester oligomer resolve into succsinic acid and THF, the aqueous solution of said ester oligomer is that phosphorus concentration is the aqueous solution of 1 ppm by weight～200 ppm by weight, and said solid acid catalyst is to have sulfonic strongly acidic cationic exchange resin.

9. the method for manufacture of a gamma-butyrolactone; Wherein, will contain 4 hydroxybutyric acid and 1, the 4-butyleneglycol is as the aqueous solution of the ester oligomer of constituent; Under heating, contact with solid acid catalyst; Make this ester oligomer resolve into gamma-butyrolactone and THF, the aqueous solution of said ester oligomer is that phosphorus concentration is the aqueous solution of 1 ppm by weight～200 ppm by weight, and said solid acid catalyst is to have sulfonic strongly acidic cationic exchange resin.

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