JPH0959190A - Production of 1,4-butanediol and/or tetrahydrofuran - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably obtain the subject compound in high yield over a long period under relatively mild conditions by hydrogenating the 1st hydrogenation product in the presence of a specific catalyst. SOLUTION: In the 1st hydrogenation process, (A) a maleic acid compound is hydrogenated in the presence of (B) a catalyst having ability to reduce C=C double bond. The reaction product is further hydrogenated in the 2nd hydrogenation process in the presence of (C) a carrying-type noble metal-Sn-based catalyst, thus obtaining the objective compound. It is preferable that the component A be fed in the form of at least one kind of solution as the solvent selected from tetrahydrofuran, γ-butylolactone and water, the component B be either carrying type noble metal-based catalyst, Cu-chromite-based catalyst or Cu-Zn-Al- contg. oxidized catalyst, and the component C be a Ru-Sn-based catalyst bearing Pt and/or Rh.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing 1,4-butanediol and / or tetrahydrofuran by catalytic hydrogenation reaction using maleic acids as raw materials. 1,4-butanediol is mainly used as a raw material for plastics such as polybutylene terephthalate and polyurethane, and is also used as a production intermediate for pyrrolidine, adipic acid and the like. Tetrahydrofuran is used as a solvent because it has a low boiling point and an excellent dissolving power, and is also used as a raw material for polytetramethylene ether glycol, tetrahydrothiophene and the like.

[0002]

2. Description of the Related Art Conventionally, many methods for hydrogenating oxygen-containing C ₄ hydrocarbons such as maleic anhydride have been reported, and the best known method is to use a copper-based catalyst. However, in this method, an organic carboxylic acid such as maleic acid cannot be directly reduced, and therefore the carboxylic acid must be once converted into an ester and then reduced.
Further, since the reaction is generally performed under hydrogen pressure of 200 atm or more, it is a disadvantageous method in terms of energy and equipment.

On the other hand, some catalysts capable of directly reducing a carboxylic acid such as maleic acid have been proposed, for example, JP-A-63-218636 and US Pat. No. 4,65.
No. 9,686 describes a method for producing tetrahydrofuran or γ-butyrolactone from an aqueous maleic acid solution using a palladium-rhenium catalyst supported on activated carbon. However, the method described in the former has a low reaction substrate concentration, and the method described in the U.S. Pat.
A hydrogen pressure of 150 atm or higher is required when carrying out the reaction. US Pat. No. 4,827,001 proposes a method for directly reducing maleic acid using ruthenium-iron oxide as a catalyst. In this method, 1,4-butanediol, Tetrahydrofuran, γ
-The butyrolactone selectivity is not sufficient.

In addition, several patents have been disclosed which were considered from a process perspective, eg US Pat. No. 5,1.
Although the specification of 96,602 describes a method of hydrogenating maleic acid or maleic anhydride in two steps, a method in which the reaction in the latter step is carried out using a Ru-Co-Ni-Zn-based catalyst is described. The results of the examples show that the activity remains at a low level. Further, in Japanese Patent Laid-Open No. 5-238971, a maleic anhydride containing a cobalt-containing catalyst is used.
Although a process for producing 1,4-butanediol which is hydrogenated in stages is disclosed, it has a drawback that the reaction requires a very high pressure of 200 to 350 bar. On the other hand, JP-A-5-246
No. 915, the hydrogenation reaction of carboxylic acids is described in
It is disclosed that a catalyst in which a noble metal of Group VIII is supported on a support made of porous carbon has high activity and excellent performance, and that coexistence of tin or the like as the second metal component improves the selectivity. .

[0005]

However, when the Ru-Sn type catalyst specifically described as a supported catalyst in the above-mentioned JP-A-5-246915 is used for the hydrogenation reaction of maleic anhydride, it gradually increases. There is a problem that Sn elutes, and industrially, improvement is desired in terms of long-term stability of catalytic activity.

As described above, any of the conventional methods is industrially insufficient, and hydrogenates maleic acids,
In order to obtain the desired products of 1,4-butanediol and / or tetrahydrofuran in high yield, it was necessary to carry out the reaction under a relatively high hydrogen pressure in order to enhance the reactivity.
The present invention provides a method for efficiently producing a 1,4-butanediol and / or tetrahydrofuran in a high yield by hydrogenating maleic acids under mild conditions by efficiently utilizing a catalyst having high reaction activity. The purpose is to provide.

[0007]

According to the present invention, when a maleic acid is hydrogenated in two stages in the presence of a hydrogenation catalyst to produce 1,4-butanediol and / or tetrahydrofuran, the first stage hydrogenation step is carried out. And a hydrogenation reaction of maleic acids in the presence of a catalyst having a C = C double bond reducing ability,
In the second-stage hydrogenation step, the first-stage hydrogenation reaction product is subjected to a hydrogenation reaction in the presence of a supported noble metal-Sn-based catalyst, which comprises 1,4-butanediol and / or tetrahydrofuran. A manufacturing method is provided.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. In the method of the present invention, maleic acids (maleic anhydride, maleic acid, an ester of maleic acid, or a mixture thereof) are used as raw materials for the reaction. The first stage hydrogenation step is carried out in the presence of a known hydrogenation catalyst capable of reducing the C = C double bond of maleic acids. For example, supported Pd-based, Ru-based, Pt-based, Rh-based catalysts, Cu-chromite-based catalysts, Cu-Zn-Al oxide-based catalysts and the like are used. These catalysts may be used alone or in combination. Above all, a supported Pd-based catalyst is preferably used.
The carrier in the case of a supported catalyst can be freely selected under the condition that it can stably exist under hydrogenation reaction conditions, for example, activated carbon, diatomaceous earth, silica, alumina, titania, zirconia, or other porous carrier. Two or more kinds can be used in combination.

[0009] Above all, from the viewpoint of activity, activated carbon-supporting P
d catalysts are preferably used. In this case, the amount of Pd metal supported may be 0.01% by weight or more, and there is no upper limit of the amount supported, but 10% by weight or less is preferable in consideration of economy. In the case of a batch reaction, the amount of the catalyst used is preferably 0.01 to 100 parts by weight with respect to 100 parts by weight of the reaction raw material of maleic acid, but depending on various conditions such as reaction temperature or reaction pressure, it is practical. It can be arbitrarily selected within the range in which a specific reaction rate is obtained.

The reaction temperature is in the range of 20 ° C to 250 ° C,
Preferably, 30 ° C to 200 ° C, more preferably 50 ° C to 1
It is within the range of 80 ° C. The reaction pressure is 0.1 MPa to 2
It is in the range of 0 MPa, preferably in the range of 0.1 MPa to 10 MPa. The reaction system may be either a liquid phase suspension reaction or a fixed bed reaction. The reaction may be carried out without a solvent, or, if necessary, a type of solvent that does not adversely affect the reaction may be used.

The solvent that can be used is not particularly limited, but specifically, water; alcohols such as methanol, ethanol, octanol and dodecanol; ethers such as tetrahydrofuran, dioxane and tetraethylene glycol dimethyl ether; other, hexane, Hydrocarbons such as cyclohexane and decalin are included. Particularly, it is preferable to dissolve maleic acid in at least one solvent selected from tetrahydrofuran, γ-butyrolactone, and water because the maleic acid has high solubility and can be easily supplied. Although the concentration can be selected as desired as long as it is equal to or lower than the saturation concentration at the temperature during reaction or supply, it is preferably 15% by weight or more in view of productivity. The initial concentration of maleic acid is usually about 20 to 60% by weight.

In the first stage hydrogenation step, the ethylenic double bond (C = C) of maleic acid is hydrogenated to reduce the acidity of the reaction substrate. The conversion rate of maleic acids is 9
It is desirable that the content is 0 mol% or more, preferably 95 mol%. Considering the necessity of sufficiently lowering the acidity of the reaction substrate in order to prevent the outflow of Sn in the catalyst used for the second stage hydrogenation reaction, specifically, the hydrogenation supplied to the second stage hydrogenation step Set the concentration of residual maleic acid in the reaction product to 1
It is desirable that the amount is 0% by weight or less, preferably 5% by weight or less.

The decrease in acidity due to hydrogenation of the C = C bond of maleic acids is caused by, for example, the pKa of maleic acid being 1.
75 and 5.83, whereas for succinic acid, 4.
00 and 5.24, and by setting the residual weight concentration of maleic acids in the hydrogenation reaction product to 10% or less, the acidity of the feedstock to the second stage hydrogenation step is significantly reduced.
When the supported Ru-Sn catalyst in the second stage hydrogenation step is brought into direct contact with maleic acid, there is a risk that Sn will be eluted into the reaction solution due to its strong acidity depending on the reaction conditions. It is very important to hydrogenate the C = C double bond of the maleic acids to reduce the acidity in the first stage hydrogenation step, so that Sn in the catalyst in the second stage hydrogenation step Elution can be completely avoided, and the performance of the catalyst can be fully obtained.

In the second stage hydrogenation step, in order to convert the hydrogenation reaction product obtained in the first step to the target 1,4-butanediol and / or tetrahydrofuran,
It is carried out in the presence of a supported noble metal-Sn catalyst, particularly a Ru-Sn catalyst, or a catalyst in which at least one metal selected from Pt and Rh is supported in combination. First
When a solvent is used in the two-stage reaction, the solution of the first-stage hydrogenation reaction product supplied to the second-stage hydrogenation step may be concentrated if necessary, and is usually 20% by weight or more, preferably 3% by weight.
A solution containing 0% by weight or more of the product is used.

As the carrier of the supported catalyst, a porous carrier such as activated carbon, diatomaceous earth, silica, alumina, titania and zirconia can be used alone or in combination of two or more kinds. In order to obtain sufficient activity of the catalyst, it is preferable that the carrier has a high surface area. Therefore, activated carbon and silica are particularly preferable among the above. As the noble metal component and the raw material compound of Sn, nitric acid, sulfuric acid, hydrochloric acid and other mineral acid salts of these metals are generally used, but organic acid salts such as acetic acid, hydroxides, oxides or generally Known organometallic compounds and complex salts can also be used.

As a method for supporting the metal component on the carrier,
Any of the methods employed in ordinary preparation methods such as the dipping method, the ion exchange method, and the sol-gel method can be applied. Of these, a particularly simple dipping method is preferably adopted. When the dipping method is used, usually, the raw material compound of the metal to be supported is dissolved in a solvent capable of dissolving the compound, such as water, to obtain a solution of the metal compound, and a separately prepared porous carrier is immersed in the solution to form a carrier. The catalyst component is supported.

The order of loading each metal component on the carrier is not particularly limited, and all the metal components may be loaded simultaneously at the same time, each component may be loaded individually, or some of the components may be combined. You may carry in multiple times. However, it is possible to further increase the reaction activity by first supporting Ru and Sn on the carrier, drying and reducing them, and then adding Pt and / or Rh and supporting them on the carrier. This P
The reason why the activity is improved by supporting t and / or Rh afterwards is not understood in detail, but by supporting afterwards Pt and / or Rh having high hydrogen activating ability or hydrogenation reaction activity, These metals can be supported on the catalyst surface,
It is presumed that the metal on this surface functions effectively in the hydrogenation reaction.

The loading amounts of the noble metal component and Sn are respectively
It is usually 0.5 to 50% by weight, preferably 1 based on the carrier.
-20% by weight. It is preferable that Pt and / or Rh coexist in an amount of 0.01 to 10 times by weight relative to Ru from the viewpoint of improving the activity. It is preferable that Sn is present in an amount of usually 0.1 to 5 times by weight with respect to the noble metal component from the viewpoint of improving the selectivity of the product.

After the solution of the metal component is dipped and carried (whenever it is dipped and carried out a plurality of times, each time), it is dried. Drying is performed at a temperature of 200 ° C. or lower under reduced pressure or while aeration with a dry gas such as air or an inert gas.
After that, firing and reduction are performed as necessary. The firing treatment is usually performed in a temperature range of 100 to 600 ° C. In addition, when performing the reduction treatment, a known liquid phase reduction method or gas phase reduction method is adopted, and in the case of the gas phase reduction method, it is usually 100 to 5
It is carried out in the temperature range of 00 ° C, preferably in the range of 200 to 350 ° C. Although details of the structure of the catalyst after the reduction treatment are unknown, it is presumed that under the above-mentioned reducing conditions, substantially all of the noble metal component is reduced to metal, and Sn is partially divalent or tetravalent. It is estimated that the price will remain.

In the case of the batch reaction, the amount of the catalyst used is preferably 0.1 to 100 parts by weight with respect to 100 parts by weight of the reaction raw material such as maleic anhydride, but the reaction temperature or the reaction pressure. Can be arbitrarily selected within the range where a practical reaction rate can be obtained according to the various conditions. Regarding the reaction conditions of the second stage hydrogenation step, the temperature is usually 130 to 35.
0 ° C, preferably 160 to 300 ° C, the reaction pressure is usually 1
The condition of -30 MPa, preferably 5-20 MPa is adopted.

The reaction system may be either a liquid phase suspension reaction or a fixed bed reaction. The reaction may be carried out without a solvent, or, if necessary, a type of solvent that does not adversely affect the reaction may be used. The solvent that can be used at this time is not particularly limited, and specific examples thereof include water; alcohols such as methanol, ethanol, octanol, and dodecanol; ethers such as tetrahydrofuran, dioxane, and tetraethylene glycol dimethyl ether; and hexane and cyclohexane. And hydrocarbons such as decalin.

The hydrogenation steps of the first and second stages are
As long as the above constitution is satisfied, each reaction process may be divided into multiple stages composed of a plurality of reactors. The 1,4-butanediol and / or tetrahydrofuran produced by the method of the present invention is separated and purified by a known method such as distillation. Unreacted raw materials remaining after the separation and purification or γ-butyrolactone as a reaction intermediate can be reused as a reaction raw material.

[0023]

EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to the description of the following Examples unless it exceeds the gist. In the following, "%" means "% by weight" unless otherwise specified.

Reference Example 1 (Example of catalyst that can be used in the first hydrogenation step) Supported catalyst manufactured by NE Chemcat (each 30
The hydrogenation reaction of maleic anhydride was carried out under the following conditions at 0 ° C. for 2 hours with hydrogen reduction), and the reaction rate constant k of the 0th-order maleic acid and 90 mol of maleic acid were calculated based on the obtained values. Table 1 shows the result of calculating the reaction time required for the conversion. (Reaction) 3 g of maleic anhydride was dissolved in 7 g of water and charged with 0.22 g of a catalyst in a 70 ml spinner stirring autoclave. Next, after thoroughly replacing the inside of the system with hydrogen, hydrogen of 3 MPa was injected at room temperature and the reaction was carried out at 80 ° C. for 1 hour. After completion of the reaction, the catalyst was filtered off and the filtrate was analyzed by liquid chromatography.

[0025]

[Table 1]

Reference Example 2 (Preparation Example of Catalyst for Second Step Hydrogenation Step) (1) RuCl ₃ was added to 3.61 ml of 5N-HCl aqueous solution.
・ 1.5Hg of 3H ₂ O, H ₂ PtCl ₆ .6H ₂ O
0.903 g, SnCl ₂ .2H ₂ O 0.950 g
After adding and dissolving, SiO 2 as a carrier was added to this mixed solution.
₂ (manufactured by Fuji Davison, special grade 12, specific surface area 679 m ² / g, pore volume 0.37 ml / g) was added in an amount of 8.55 g and thoroughly stirred to impregnate. After removing water as a solvent at 60 ° C. and 25 mmHg in a rotary vacuum dryer, this was dried at 150 ° C. for 2 hours in a nitrogen atmosphere, and then reduced at 300 ° C. for 2 hours in a hydrogen atmosphere. .1% Ru-3.4% Pt-5.0% Sn / Si
A catalyst of O ₂ was prepared. (2) In the same manner as the above procedure, 5.1% Ru-
A 3.4% Pt-3.0% Sn / SiO ₂ catalyst was prepared.

Example 1 <First Step Hydrogenation Step> 50 g of maleic anhydride and 50 g of water
And 0.5 g of 2% Pd / C (manufactured by NE Chemcat) were hydrogen-reduced at 200 ° C. for 2 hours and charged in a 200 ml induction stirring autoclave. Next, after the system was sufficiently replaced with hydrogen, the hydrogen pressure was 7 MPa and 80
The reaction was carried out at 0 ° C for 1 hour. After completion of the reaction, the catalyst was filtered off and the filtrate was analyzed by liquid chromatography.
As a result, the conversion rate of maleic anhydride was 100 mol%,
The selectivity of succinic acid was 99.6 mol% and the selectivity of fumaric acid was 0.1 mol%.

<Second Step Hydrogenation Step> Water is added to the reaction product obtained in the first step hydrogenation step to obtain a succinic acid concentration of 50% by weight.
50 g of the obtained aqueous solution of succinic acid was placed in an autoclave having a capacity of 200 ml, and 4 g of the catalyst prepared in Reference Example 2 (1) was further charged into the autoclave having a volume of 200 ml and stirred to 2M.
Hydrogen of Pa was injected under pressure and the temperature was raised to 240 ° C. While maintaining the internal temperature of the autoclave at 240 ° C., hydrogen was introduced under pressure to raise the hydrogen pressure to 7 MPa, and the reaction was carried out for 2 hours while keeping this pressure while constantly supplementing the consumed hydrogen. After completion of the reaction, the reaction product was analyzed by gas chromatography to find that the conversion rate of succinic acid was 100 mol%, and the yield of succinic acid was 67.8 mol% for THF and 10.5 mol% for γ-butyrolactone. , 1,4-butanediol is 4.
6 mol% and a total yield of maleic anhydride to 6 respectively
It was obtained at 7.6 mol%, 10.5 mol% and 4.6 mol%. Among the reaction products, by-product yields were 3.0 mol% of propanol and 5.1 mol% of butanol as by-products, and the total yield of maleic anhydride was 3.0 mol%. Mol%, 5.1 mol%, and, based on the C of succinic acid charged from the gas phase, 7.3% relative to succinic acid yield, and total maleic anhydride yield is 7.3 mol%. Gas components (methane, ethane, propane, butane) were detected.

Example 2 <First Stage Hydrogenation Step> 15 g of maleic anhydride and 35 g of water
And 0.2 g of 5% Pd / C (manufactured by NE Chemcat) were hydrogen-reduced at 300 ° C. for 2 hours, and then charged in a 200 ml induction stirring autoclave. Next, after thoroughly replacing the inside of the system with hydrogen, the hydrogen pressure was 1 MPa and 80
The reaction was carried out at 0 ° C for 1 hour. After completion of the reaction, the catalyst was filtered off and the filtrate was analyzed by liquid chromatography.
As a result, the conversion rate of maleic anhydride was 100 mol%,
The selectivity of succinic acid was 100 mol%.

<Second-stage hydrogenation step> 50 g of a 50 wt% aqueous solution of the succinic acid aqueous solution obtained in the first-step hydrogenation step was placed in an autoclave having a capacity of 200 ml, and further, Reference Example 2 (1). 4 g of the catalyst prepared in Step 2 was added, 2 MPa of hydrogen was injected under pressure at room temperature with stirring, and the temperature was raised to 240 ° C. While maintaining the internal temperature of the autoclave at 240 ° C., hydrogen was injected to increase the hydrogen pressure to 7 MPa, and hydrogen was circulated at the reactor outlet at 30 normal liters / hour,
The reaction was carried out at this pressure for 2 hours. During this period, H _{2 is} distributed
And the light-boiling components such as THF were separated from the reaction system. After completion of the reaction, the reaction product was analyzed by gas chromatography to find that the conversion rate of succinic acid was 100.
The yield was 84.1 mol% and γ-butyrolactone was 0.4 mol% with respect to the yields of succinic acid. In addition, the reaction product contained propanol as a by-product in a yield of 4.3 mol% and butanol in a yield of 3.9 mol% as a by-product. C
Gas components (methane, ethane, propane, butane) of 8.2% were detected based on the above. The total maleic anhydride yields of these products were similar.

Example 3 (Metal Component Elution Test) The following metal component elution test showing the stability of the catalyst was carried out.
In addition, when this elution test is performed in a hydrogen atmosphere, a proper evaluation cannot be performed because, for example, a reaction from maleic acid to succinic acid proceeds, so that the elution test was performed in a nitrogen atmosphere.

(1) Maleic anhydride 4.5 g, water 10.
5 g and 0.4 g of the catalyst prepared in Reference Example (2)
After charging in a 0 ml autoclave and replacing the inside with nitrogen, the mixture was treated with nitrogen at 1 atm at 240 ° C. for 1 hour. After removing the catalyst from the treatment liquid, the amount of the metal component eluted in the treatment liquid was quantified by the inductively coupled plasma emission spectrometry (ICP-AES). As a result, Ru and Pt were below the detection limit (the supported amount of 0. 1 wt% or less), but 3.8 wt% of the carried amount of Sn was eluted, and Ru-
Pt-Sn / SiO ₂ catalyst was found to be not be able to exist stably. (2) except that maleic anhydride was changed to succinic anhydride
The same process as the above (1) was performed. The elution of all metals of Ru, Pt, and Sn was below the detection limit of ICP-AES. From this result, in the presence of succinic acid, Ru-Pt-
It was found that the Sn / SiO ₂ catalyst existed stably without elution of metal components. (3) Maleic anhydride 10 g, water 10 g, 5% Pd / C
(Manufactured by NE Chemcat) 0.44 g to 70 m
After charging in an autoclave and replacing the inside with nitrogen,
When the amount of Pd eluted in the treatment liquid was quantified in the same manner by treating with nitrogen at 1 atm at 80 ° C. for 1 hour, it was found to be below the detection limit and <0.05 ppm. (4) The same treatment as in (3) above was performed for 7 hours, but no Pd elution was observed. From the above results, it is judged that the method of the present invention greatly contributes to maintaining the stability of the catalyst, and the catalyst can be stably used for a long period of time.

[0033]

According to the method of the present invention, maleic anhydride, maleic acid, succinic anhydride, succinic acid, γ-butyrolactone or a mixture thereof is used as a raw material, and the reaction is carried out under relatively mild reaction conditions by catalytic hydrogenation reaction. Thus, 1,4-butanediol and / or tetrahydrofuran can be stably produced in a high yield over a long period of time, and its industrial utility value is extremely large.

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Claims (10)

[Claims] 1. A maleic acid is added in the presence of a hydrogenation catalyst.
When 1,4-butanediol and / or tetrahydrofuran is hydrogenated in a stage, maleic acids are subjected to a hydrogenation reaction in the presence of a catalyst having a C = C double bond reducing ability in the first stage hydrogenation step. Attached in the 2nd stage hydrogenation process
A process for producing 1,4-butanediol and / or tetrahydrofuran, which comprises subjecting a step hydrogenation reaction product to a hydrogenation reaction in the presence of a supported noble metal-Sn catalyst. 2. The catalyst of the first stage hydrogenation step is a supported noble metal catalyst, Cu-chromite catalyst, Cu-Zn-Al.
2. A catalyst selected from the group of oxide catalysts containing
The method described in. 3. A supported precious metal-based catalyst is Pd, Ru, P.
The method according to claim 2, which is a supported catalyst containing a noble metal selected from the group of t and Rh. 4. The method according to claim 3, wherein the supported noble metal catalyst does not contain Sn. 5. The method according to claim 4, wherein the supported noble metal-based catalyst is a Pd-based catalyst. 6. The method according to claim 5, wherein the Pd-based catalyst is a Pd / C-based catalyst. 7. The noble metal of the supported type noble metal-Sn catalyst is
The method according to claim 1, wherein the method is selected from Ru, Pt and Rh. 8. The supported noble metal-Sn catalyst is Ru-S.
The method according to claim 7, which is an n-based catalyst. 9. The Ru—Sn catalyst further comprises Pt and Rh.
The method according to claim 8, wherein the catalyst is a catalyst supporting a combination of at least one metal selected from the group consisting of: 10. The method according to claim 1, wherein the maleic acid is supplied as a solution of at least one selected from tetrahydrofuran, γ-butyrolactone, and water.