KR100538979B1 - Method for the preparation of 1,4-butanediol from maleic ester - Google Patents

Abstract

The present invention relates to a method for preparing 1,4-butanediol from maleic acid ester, wherein the method according to the present invention for producing 1,4-butanediol by hydrogenating maleic acid ester in the presence of a catalyst having a composition of the formula In the low molar ratio of hydrogen to the reactants, it exhibits high selectivity, high yield and high productivity, and 1,4-butanediol can be produced stably for a long time without performing the reactivation operation of the catalyst:

CuO (a) MnO ₂ (b) M (c) SiO ₂ (d)

Wherein a, b, c and d represent percentages by weight, a is 40 to 90, b is 0.15 to 5, c is 0.001 to 5, d is 5 to 50, and M is An oxide of at least one metal element selected from zinc (Zn), platinum (Pt), palladium (Pd), rhenium (Re), ruthenium (Ru), and rhodium (Rh).

Description

Method for producing 1,4-butanediol from maleic acid ester {METHOD FOR THE PREPARATION OF 1,4-BUTANEDIOL FROM MALEIC ESTER}

The present invention relates to a method for producing 1,4-butanediol from maleic acid ester, and more particularly to a method for efficiently producing 1,4-butanediol by hydrogenating maleic acid ester under a specific copper-silica-based complex catalyst. will be.

1,4-Butanediol is a synthetic raw material and intermediates such as polybutylene terephthalate resin, plasticizer, polyurethane, alkyd resin, gamma-butyrolactone and tetrahydrofuran, which are engineering plastics, and are used in the construction, clothing, petrochemical and electronic industries. It is an important raw material used in various fields.

As a method for producing 1,4-butanediol, various synthetic methods are industrially used according to raw materials such as acetylene, butadiene, propylene oxide and maleic anhydride.

For example, the Reppe method uses acetylene and formaldehyde as raw materials, and reacts at 100 ° C. and 1 atm using a copper acetylide catalyst to make 2-butyne-1,4-diol, which is called Raney 1) 4-butanediol is synthesized by liquid phase hydrogenation under a nickel catalyst at a temperature of 50 to 60 ℃ and a pressure of 200 to 300 atm.

At Mitsubishi, Japan, butadiene is oxidized and acetoxylated under a palladium-tellurium catalyst at a temperature of 80 ° C. and a pressure of 40 atm to form 1,4-diacetoxy-2-butene, which is converted into a palladium catalyst. Hydrogenation is followed by hydrolysis with a strongly acidic ion exchange resin catalyst to produce 1,4-butanediol.

A method for producing 1,4-butanediol using propylene oxide as a raw material is to produce 1,4-butanediol by isomerizing propylene oxide to convert it to allyl alcohol, hydroformylating it, and then hydrogenating it.

However, the methods for producing 1,4-butanediol using acetylene, butadiene or propylene oxide as raw materials have problems such as price of raw materials, supply and demand instability, complexity of the process, etc. A method of using maleic anhydride as a raw material has been actively developed.

Method for producing 1,4-butanediol using maleic anhydride as a raw material, 1) a method for producing 1,4-butanediol by the selective hydrogenation of maleic anhydride to gamma-butyrolactone and then secondary hydrogenation; 2) esterification of maleic anhydride with alcohol and then hydrogenation to prepare 1,4-butanediol and gamma-butyrolactone; And 3) hydrogenated aqueous maleic acid solution to produce 1,4-butanediol and tetrahydrofuran.

Method 1) for preparing 1,4-butanediol by hydrogenating maleic anhydride under a catalyst in two stages is a technique in which numerous catalysts and processes have been tried due to the simplicity of the process. However, the hydrogenation process of maleic anhydride has many problems from an industrial point of view. For example, this method requires the use of a catalyst containing a large amount of chromium, which is environmentally problematic, or an existing copper-based hydrogenation catalyst with low thermal stability, and is catalyzed by tar generated when maleic anhydride is vaporized. Problem of the catalyst itself such as deactivation of the catalyst and shortening of the catalyst life, the hydrogenation reaction must be carried out at a relatively high temperature condition in order to maintain high conversion rate, and the reaction rate must be lowered due to the high heat of reaction. It is low and there is a lot of room for improvement in terms of conversion rate.

In addition, the process of preparing 1,4-butanediol and tetrahydrofuran by directly hydrogenating aqueous maleic acid solution uses a noble metal catalyst such as palladium-renium despite the simplicity of the process, and the process is complicated by the liquid phase slurry reaction. In addition, there are disadvantages in that the catalyst needs to be regenerated at any time.

On the other hand, the method 2) of hydrogenating maleic acid ester requires an additional esterification process when maleic anhydride is used as a starting material, but it is possible to control the reaction conditions so that a specific product can be maximized in the distribution of each product. After that, the product is separated and purified, thereby producing 1,4-butanediol (BDO), gamma-butyrolactone (GBL), tetrahydrofuran (THF), and the like. Therefore, the method of preparing 1,4-butanediol, gamma-butyrolactone, and the like by esterifying maleic anhydride with alcohol and then hydrogenating them is performed by various products such as gamma-butyrolactone, 1,4-butanediol, tetrahydrofuran, etc. It can be produced in one process, and excellent in reaction selectivity and reaction productivity compared to the two-stage hydrogenation reaction process of maleic anhydride 1), can be operated under relatively low temperature and mild reaction conditions, and because both reactants and products are liquid at room temperature, they are transported. It is convenient to move and to reduce the process failure.

As a hydrogenation catalyst of maleic acid ester used for the said method 2), the catalyst which mainly contains copper is mainly used. In U.S. Patent Nos. 4,584,419 (Korean Patent Publication No. 91-8935) and 4,751,334, copper chromite-type catalysts are used as hydrogenation catalysts of maleic acid esters, and reaction temperatures of 35 to 55 atm and reaction temperatures of 150 to 240 ° C. And a process for producing 1,4-butanediol by hydrogenation at relatively mild conditions with a molar ratio of hydrogen to ester of 250 to 450: 1. At this time, the selectivity of each product may be improved by adjusting reaction conditions such as reaction pressure, temperature and hydrogen molar ratio, but in general, 1,4-butanediol 75%, gamma-butyrolactone 14%, tetrahydrofuran 5%, and unreacted Ester yields such as 5% appear. Therefore, in order to increase the yield of 1,4-butanediol, the hydrogenation process of gamma-butyrolactone is recycled.

In addition, U.S. Patent No. 4,613,707 uses a catalyst in which copper and copper aluminum borate, which does not contain a chromium component, as a hydrogenation catalyst for maleic acid ester are supported on a crystalline Al ₄ B ₂ O ₉ carrier, and a reaction pressure of 135 atm and Disclosed is a method of producing 1,4-butanediol and the like by hydrogenating one step at a reaction temperature of 200 ° C. In this case, the conversion of ester is 28 to 34%, the selectivity of 1,4-butanediol is 40 to 52%, the selectivity of gamma-butyrolactone is 22 to 40%, and the selectivity of methyl-4-hydroxybutyrate is 15 to 18%.

Korean Patent Publication No. 96-4880 discloses a reaction pressure of 20 to 70 atm, a reaction temperature of 160 to 250 ° C, and an ester using a catalyst having a copper component supported on a carrier such as silicon oxide, zirconium oxide, titanium oxide, or the like. A method for preparing 1,4-butanediol in a one-step reaction at a hydrogen molar ratio of 30 to 500: 1 is obtained with a yield of 60 to 80% of 1,4-butanediol and 10 to 30% of gamma-butyrolactone. .

In addition, WO 1999-35114 (Korean Patent No. 2000-76035) discloses a process for preparing 1,4-butanediol and tetrahydrofuran from a mixture of succinic ester and gamma-butyrolactone by a method consisting of two consecutive hydrogenation. It is starting. In this method, a copper-zinc oxide or copper chromite catalyst is used as a catalyst, and under the conditions of a reaction pressure of 60 to 100 atm, a reaction temperature of 160 to 250 ° C., and a molar hydrogen ratio of ester to ester of 30 to 150: 1, Although 1,4-butanediol is produced in a relatively high yield with a yield of 90% of 4-butanediol, 9% of tetrahydrofuran, and 1% of butyl alcohol, maleic acid ester should be hydrogenated with succinic acid ester and gamma, a primary hydrogenation product. There is a need for improvement in the complexity of the multistage reaction process and the separation and purification process of the product and the reaction selectivity and stability of the catalyst, such as butyrolactone is separated and recycled to the hydrogenation reaction.

As described above, the method for preparing 1,4-butanediol by two-step hydrogenation from the conventional maleic acid ester has a high selectivity and high yield using only one-step hydrogenation step because the process is complicated despite excellent stability and productivity of the reaction. There is a need for a method for producing 1,4-butanediol.

The present inventors have proposed a Cu-SiO ₂ based catalyst (Korean Patent Application No. 2001-47151) prepared by a method of stabilizing a copper oxide precursor particle having nano size with colloidal silica as a hydrogenation and dehydrogenation catalyst. As a result of the hydrogenation reaction using the catalyst, there was a problem such as low catalytic activity, low selectivity and low reaction stability when operating under low temperature, low pressure, and low hydrogen molar ratio.

Accordingly, an object of the present invention is to produce high selectivity, high yield and high productivity even in a condition where hydrogen supply ratio to maleic acid ester is low in producing hydrogenated 1,4-butanediol in one step directly from maleic acid ester. Another object of the present invention is to provide a hydrogenation method using a liquid hydrogenation catalyst which maintains long-term reaction stability and has a low environmental load of waste catalyst.

In order to achieve the above object, the present invention provides a method for producing 1,4-butanediol comprising hydrogenating maleic acid ester in the presence of a catalyst represented by the following formula (1):

Formula 1

CuO (a) MnO ₂ (b) M (c) SiO ₂ (d)

Where

a, b, c and d are percentages by weight, a is 40 to 90, b is 0.15 to 5, c is 0.001 to 5, d is 5 to 50,

M represents an oxide of at least one metal element selected from zinc (Zn), platinum (Pt), palladium (Pd), rhenium (Re), ruthenium (Ru), and rhodium (Rh).

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

In general, when the maleic acid ester is hydrogenated, the fraction of gamma-butyrolactone and butanediol as a product is greatly influenced by the reaction kinetics. That is, since gamma-butyrolactone is primarily produced by hydrogenation from maleic acid ester, and hydrogenation proceeds to produce butanediol, the reaction is advantageous at high temperature and low pressure, which are conditions of gas phase reaction, for the production of gamma-butyrolactone. For the preparation of butanediol, low-temperature, high-pressure reaction conditions are required for the liquid phase reaction. Therefore, in order to obtain 1,4-butanediol in high yield from maleic acid ester, a catalyst must be designed and manufactured to exhibit high activity, selectivity, and thermal stability at low temperature and high pressure.

The inventors of the present invention, in Korean Patent Application No. 2001-47151, can control copper oxide particle size and ultimately stabilize with silica when produced by the method of producing copper particles in hydrogel form and aged in the presence of nano-sized silica. A catalyst with nanorod copper oxide crystals is made, which has been shown to show high performance in the liquid phase hydrogenation of maleic acid esters. However, in the present invention, the catalyst was improved to have high activity, high selectivity, and high productivity under low temperature, high pressure, and low hydrogen molar ratio for industrialization. According to the present invention, a hydrogenation reaction catalyst represented by Chemical Formula 1 is used to prepare 1,4-butanediol from maleic acid ester.

In the composition of the catalyst, the copper oxide is included in the range of 40 to 90% by weight, the manganese oxide is 0.15 to 5% by weight to increase the activity and selectivity of the copper oxide, copper component activity and long-term reaction stability Metal (M) oxide added for promotion is included in the range of 0.001 to 5% by weight. In addition, in the catalyst, silica serves to stabilize copper, zinc and metal (M) oxide, the content of silica in the catalyst is in the range of 5 to 50% by weight.

The catalyst of the formula (1) used in the present invention, for example, by adding alkali to a mixed aqueous solution of copper salt and manganese salt to coprecipitate the copper and manganese components in the form of a hydrogel, and the nano-sized silica in the resulting coprecipitation solution The mixed slurry was hydrothermally aged, the aged slurry solution was filtered to separate the precipitates, washed, and the washed precipitates were dried and then impregnated with a solution containing a salt of the metal (M). It can be produced by a method comprising the step of supporting, drying and baking. At this time, when the metal (M) is zinc, the zinc salt is preferably used in advance in the coprecipitation step.

This will be described in more detail as follows.

(1) Preparation and Coprecipitation of Mixed Slurry Solution

First, among the constituents of the hydrogenation reaction catalyst of the present invention, salts of copper and manganese, for example, water-soluble salts such as nitrates or hydrochlorides, are mixed with water, slurryed, and co-precipitated with alkali.

At this time, the concentration of the water-soluble salt is adjusted to the range of 5 to 25% by weight, respectively, and the temperature of the slurry solution is preferably kept constant in the range of 1 to 30 ℃ to maintain the hydrogel form during coprecipitation.

Specific examples of alkalis used as coprecipitation agents are aqueous solutions of sodium hydroxide, sodium carbonate, sodium bicarbonate, ammonium carbonate and ammonium bicarbonate or other suitable aqueous alkali solutions, which coprecipitate the metal components in the form of mixed hydroxides or hydroxide carbonates. At this time, the amount of coprecipitation is adjusted so that the pH of the filtrate is in the range of 5 to 10, preferably 6 to 9 after the aging process. When the pH is high, the nano-sized silica added after coprecipitation is dissolved, and when the pH is low, precipitation of metal elements is not completely achieved, and it is difficult to obtain crystal grains of an oxide state during the aging process.

(2) Preparation of Silica-Added Mixed Slurry

Nano-sized silica is added to the coprecipitation solution to prepare a mixed slurry. Examples of the silica include silica such as colloidal silica, silica sol or water glass, of which colloidal silica is preferable, especially pH 8 to 10, surface area of 100 to 600 m 2 / g, particle size stabilized with ammonia or sodium Most preferred are colloidal silicas of 4 to 60 nano size.

Colloidal silica is stabilized with ammonium ions (NH ₄ ⁺ ), sodium ions (Na ⁺ ) or other alkali metals, particle size 4 to 60 nm, surface area 100 to 600 m 2 / g, concentration based on silica Anything in the range of 1 to 60% by weight may be used, and commercial products include Ludox (DuPont), Nalcoag (Nalco), Snowtex (Nissan chemical), etc. G) and the like.

(3) hydrothermal aging

The mixed silica slurry solution is hydrothermally aged at 50-100 ° C. for at least 0.5 hours.

The hydroxide component is crystallized in the form of a mixed oxide having crystallinity in the course of hydrothermal aging in the presence of nano-sized silica particles, wherein the nano-sized silica particles play a major role in controlling the crystal size of the catalyst component Done. At this time, the silica particles themselves perform a gelling process to simultaneously aggregate the catalyst particles, thereby facilitating post-treatment processes such as water washing. As such, the catalyst prepared according to the method of the present invention by using the nano-sized silica particles was X-ray diffraction spectroscopy (XRD) by X-ray line broadening analysis. In analysis, nanorod-shaped crystal particles having a copper oxide crystal diameter of 50 nm or less can be obtained, and the BET specific surface area of the particles is 80 m 2 / g or more and is thermally stable.

(4) Separation, washing and drying

After filtering the aged slurry solution, the precipitate is separated and washed with deionized water to remove excess sodium or ammonium ions and anions. At this time, the concentration of the alkaline cation used as the co-precipitation agent and the stabilizer of the colloidal silica is controlled to be 1000 ppm or less, preferably 500 ppm or less, based on the dried catalyst particles in the oxide state.

The catalyst material obtained as above is dried at 100 to 300 ° C. for 3 to 30 hours.

(5) Support of metal (M) component

The catalyst composed of the copper-manganese-silica component prepared by the above method also shows high activity in the hydrogenation of maleic acid esters, but in order to further improve the long-term reaction stability of the catalyst, a third metal (M) such as Zn, Pt, It is effective to carry out further improvement by supporting components such as Ru, Re, Rh and Pd. The addition of the metal component can alleviate the deactivation due to carbon deposition on the catalyst surface in addition to increasing the activity of the main component copper.

The method of supporting the metal (M) component may be performed by immersing the dried copper-manganese-silica powder after washing in a solution of the precursor compound of the metal (M) component dissolved in water or an organic solvent and then filtering. have. Among the metals (M), zinc is preferably prepared by co-precipitation of zinc nitrate in the process of co-precipitation of copper and manganese, and Pt, Rh, and Pd are nitrates or amine complexes (Pd (NH ₃ ) ₄ (NO ₃ ), respectively). ₂ ) is used, Ru is ruthenium carbonyl (Ru ₃ (CO) ₁₂ ), Re is a rhenium oxide (Re ₂ O ₇ ), but it is preferable to use, but not limited to the compound and other salts or complexes may be used. Do.

(6) forming and firing

The catalyst prepared as described above may be molded in some cases.

The molding method is selected according to the particle size, shape, bulk density, loading amount of the catalyst active ingredient, etc. of the catalyst component in the final molded product catalyst, and examples thereof include extrusion, tableting, and supporting. For example, the water content of the catalyst cake filtered after washing may be adjusted in the range of 45 to 50%, and may be directly extruded, or may be molded by spray drying to obtain and powder the powder. Alternatively, it may be molded by a method of supporting it on a carrier having macropores.

The molded catalyst is fired to neutralize the catalyst by maximizing the residual amount of hydroxyl groups contained in the silica, and the firing temperature is preferably in the range of 300 to 1000 ° C, preferably 400 to 800 ° C, and 2 to Firing for 10 hours. If the firing temperature is too high, the size of the copper particles increases, and the activity decreases. If the firing temperature is too low, the activity and selectivity are simultaneously reduced due to the increase of the hydrocracking reaction.

According to the present invention, in order to prepare gamma-butyrolactone from maleic acid ester by using the catalyst prepared by the above-described method in a hydrogenation reaction, first, an oxide catalyst is used at 100 to 250 ° C. using hydrogen or a hydrogen-containing gas. It is preferable to use after activation for about 1 to 60 hours.

The gas phase hydrogenation of maleic acid esters using the catalyst is performed in a fixed bed reactor of at least 90% conversion of maleic acid ester (or succinic acid ester), preferably at least 98% of conversion (1,4-butanediol, gamma-buty). Selectivity comprising rockactone and tetrahydrofuran), preferably at least 95% or higher, or at reaction conditions for producing 1,4-butanediol. This is because, when the conversion rate is low, unreacted maleic acid ester (or succinic acid ester) and the product 1,4-butanediol and gamma-butyrolactone form an azeotrope and cause difficulty in separation and purification of the product.

Thus, the reaction has a weight hourly space velocity (WHSV) of maleic acid ester of 0.05 to 5.0 hr ⁻¹ , preferably 0.1 to 2.0 hr ⁻¹ , reaction temperature of 120 to 300 ° C., preferably 140 To 260 ° C. When the reaction temperature is higher at higher temperatures, high conversion and productivity can be obtained, but the produced 1,4-butanediol is gradually hydrogenated to produce by-products such as butyl alcohol and tetrahydrofuran, which greatly reduces the selectivity and deteriorates the catalyst. It can also cause deactivation. In addition, at temperatures below 120 ° C., the conversion is greatly reduced and the catalyst is deactivated due to the deposition of high boiling by-products.

The pressure of the reaction is in the range of 20 to 150 atm, preferably 30 to 120 atm. Increasing the reaction pressure to more than 150 atm yields a high conversion, but the degree of perhydrogenation is intensified, increasing the side reaction fraction to butyl alcohol and tetrahydrofuran, which is undesirable. The selectivity of 1,4-butanediol is very low.

Therefore, the present invention is characterized in that it performs at a lower pressure than the conventional technology (150 ~ 300 atm), which is a great advantage in the convenience of process operation and the economics of the equipment cost.

The maleic acid ester may be reacted by supplying an appropriate amount to the heated reaction space to vaporize, or by vaporizing it through a spray nozzle in a vaporizer using hydrogen used in the reaction, and then supplying it to the reactor. The reactant supplied to the vaporizer may be maleic acid ester or an alcohol solution having 20 to 80% by weight of maleic acid ester, preferably 30 to 60% by weight. Compounds used for maleic acid esters include dimethyl maleate, diethyl maleate, dipropyl maleate, diisopropyl maleate, dibutyl maleate, diisobutyl maleate, dipentyl maleate, dihexyl maleate, di Isohexyl maleate, dioctyl maleate and diisooctyl maleate, and the like, and dimethyl maleate, diethyl maleate, dipropyl maleate, diisopropyl maleate, dibutyl maleate and the like. In addition, the alcohol used as the solvent is preferably methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol or the like having an alkyl corresponding to the alkyl group of maleic acid ester.

The hydrogen molar ratio to maleic acid ester should be increased in order to maintain high activity and high selectivity of the catalyst and to improve the reaction productivity, but the appropriate molar ratio is 50 to 1,000: 1, more preferably 50 to 1 because the cost of recovering and reusing excess hydrogen is greatly increased. It is in the range of 600: 1.

The invention can be better understood by the following examples, which are intended for the purpose of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims. Under the reaction conditions of each example, the conversion rate of maleic acid ester itself was 100%.

Example 1

(1) Preparation of Hydrogenation Catalyst CuO (72.2) MnO ₂ (2.5) ZnO (0.3) SiO ₂ (25) (indicated by weight in parentheses)

1500 ml of 200 g of copper nitrate [Cu (NO ₃ ) ₂ 3H ₂ O] and 7.53 g of manganese nitrate [Mn (NO ₃ ) ₂ 6H ₂ O], 1.0 g of zinc nitrate [ZnO (NO ₃ ) ₂ 6H ₂ O] To a solution dissolved in distilled water of 68.6 g of sodium hydroxide dissolved in 500 ml of water was added to precipitate. At this time, the temperature of the slurry solution was adjusted not to exceed 20 ° C by the heat of neutralization. 78.0 g of colloidal silica aqueous solution Ludox SM-30 (stable sodium, containing 30 wt% silica, manufactured by Dupont) was added to the precipitated solution, and aged at 85 ° C for 6 hours. The precipitated slurry solution was washed with distilled water, filtered, dried at 120 ° C. for 12 hours, and first calcined at 300 ° C. The first calcined catalyst was pulverized to make a powder, press-molded, crushed to 20-40 mesh, sorted and calcined at 750 ° C. for 5 hours. The sodium content in the calcined catalyst oxide was 180 ppm.

(2) catalyst activation

1.0 g of the calcined oxide catalyst was charged in a tubular reactor (inner diameter 12 mm, length 25 cm), and gradually heated up while flowing 5% H ₂ / N ₂ mixed gas, and activated at 180 ° C. for 6 hours.

(3) Hydrogenation of Diethyl Maleate

After the reduction activation of the catalyst, the reactor temperature was adjusted as in Table 1 and the pressure was adjusted using hydrogen gas. After adjusting the flow rate of the hydrogen gas flow to the reactor 49% by weight of diethyl maleate containing ethyl alcohol solution was injected into the reaction in the same direction as the flow of hydrogen gas using an HPLC (high performance liquid chromatography) pump. The product was collected under the same pressure as the reaction pressure and analyzed by GC (gas chromatography). After confirming that the reaction was stable for more than 100 hours, the experiment was performed for about 500 hours while changing the reaction conditions. The reaction results are shown in Table 1 below.

Reaction temperature (℃) Reaction pressure (atmospheric pressure) H ₂ / DEM (molar ratio) DEM WHSV (hr ^-1 ) Yield (mol%) THF BuOH GBL BDO DES 160 40 300 0.32 1.3 0.0 6.6 91.9 0.1 160 40 300 0.50 0.4 0.1 7.9 90.7 0.9 DEM: diethyl maleate, DES: diethyl succinate, THF: tetrahydrofuran, BuOH: butyl alcohol, GBL: γ-butyrolactone, BDO: butanediol

Comparative Example 1

A catalyst consisting of only copper and silica (CuO (80) SiO ₂ (20)) was prepared in the same manner as in Example 1, and charged in the same reactor in the same manner, followed by hydrogenation of diethyl maleate. The experimental results are shown in Table 2.

Reaction temperature (℃) Reaction pressure (atmospheric pressure) H ₂ / DEM (molar ratio) DEM WHSV (hr ^-1 ) Yield (mol%) THF BuOH GBL BDO DES 160 40 300 0.32 0.6 0.1 15.1 64.9 19.2 180 40 300 0.32 1.8 0.3 22.6 74.6 0.7

From the results in Table 2, when a catalyst consisting of only copper and silica (CuO (80) SiO ₂ (20)) is used, the activity and selectivity are low under mild reaction conditions, and unreacted diethyl succinate is 1% or less. In the high conversion operating conditions, the selectivity of 1,4-butanediol is increased, but the production of gamma-butyrolactone and tetrahydrofuran is significantly increased.

Comparative Example 2

A commercial maleic acid ester hydrogenation catalyst (Engelhard 72F-69A, commercially available from Engelhard) was crushed and screened to a size of 20-40 mesh in the same manner as in Example 1, and the same reactor was charged in the same manner. It was then activated and subjected to hydrogenation of diethyl maleate. The experimental results are shown in Table 3.

Reaction temperature (℃) Reaction pressure (atmospheric pressure) H ₂ / DEM (molar ratio) DEM WHSV (hr ^-1 ) Yield (mol%) THF BuOH GBL BDO DES 160 40 300 0.32 1.0 0.2 9.5 88.5 0.8 160 40 300 0.50 0.6 0.1 10.5 85.2 3.6

From Table 3, when a commercial maleic acid ester hydrogenation catalyst for producing 1,4-butanediol is used, the production of 1,4-butanediol is lower than that of using the hydrogenation catalyst of the present invention (Table 1), and gamma-butyro It can be seen that the production of lactones is relatively high.

Comparative Example 3

CuO (73) MnO ₂ (6) ZnO (1) SiO ₂ (20) catalysts were prepared and activated in the same manner as in Example 1 to investigate the catalyst performance depending on the amount of zinc and manganese added. It was. The experimental results are shown in Table 4.

Reaction temperature (℃) Reaction pressure (atmospheric pressure) H ₂ / DEM (molar ratio) DEM WHSV (hr ^-1 ) Yield (mol%) THF BuOH GBL BDO DES 160 40 300 0.32 1.6 0.2 14.9 83.2 0.1

The results show that the improvement effect appears within a very limited range.

Example 2

A CuO (72.2) MnO ₂ (2.5) ZnO (0.3) SiO ₂ (25) catalyst was prepared in the same manner as in Example 1. The cake washed and filtered during the manufacturing process was dried until the moisture content was about 55%, and then molded by extrusion. The calcined catalyst was calcined at 300 ° C. for 5 hours, and then the calcined powder was immersed in a solution in which rhenium oxide (Re ₂ O ₇ ) was dissolved in a mixed solution of water and acetone. It was calcined during to prepare (CuO (72.2) MnO ₂ (2.5) ZnO (0.3) SiO ₂ (25)) (99.5) Re ₂ O ₇ (0.5) catalyst.

The catalyst was activated in the same manner as in Example 1 and the catalyst performance was investigated, and the results are shown in Table 5.

Reaction temperature (℃) Reaction pressure (atmospheric pressure) H ₂ / DEM (molar ratio) DEM WHSV (hr ^-1 ) Yield (mol%) THF BuOH GBL BDO DES 160 40 300 0.32 0.4 0.1 6.4 91.8 1.3

Example 3

The CuO (72.2) MnO ₂ (2.5) ZnO (0.3) SiO ₂ (25) catalyst of Example 2 was crushed to form powders of 100 mesh or less, and Pt (NH ₃ ) ₄ (NO ₃ ) ₂ was dissolved in water and methanol. After dissolving, the powder was immersed in this solution to further support the Pt component ((CuO (72.2) MnO ₂ (2.5) ZnO (0.3) SiO ₂ (25)) to prepare a (99.8) PtO (0.2) catalyst). The supported powder was molded by tableting and calcined for 5 hours at 750 ° C. The catalyst was charged and activated in the same manner as in Example 1 to investigate the catalytic performance, and the results are shown in Table 6.

Reaction temperature (℃) Reaction pressure (atmospheric pressure) H ₂ / DEM (molar ratio) DEM WHSV (hr ^-1 ) Yield (mol%) THF BuOH GBL BDO DES 160 40 300 0.32 0.3 0.1 6.2 91.8 1.5

Example 4

The CuO (72.2) MnO ₂ (2.5) ZnO (0.3) SiO ₂ (25) catalyst of Example 1 was charged and activated in a reactor, and 42% by weight of dimethyl maleate (DMM) containing methyl alcohol solution was fed to the reactor Hydrogenation reactivity was investigated. The reaction results are shown in Table 8.

Reaction temperature (℃) Reaction pressure (atmospheric pressure) H ₂ / DMM (molar ratio) DMM WHSV (hr ^-1 ) Yield (mol%) THF BuOH GBL BDO DMS 160 40 300 0.32 1.1 0.0 9.2 88.3 1.4

The method of the present invention has high selectivity, yield and high productivity under reaction conditions in which the molar ratio of hydrogen to maleic acid ester is 1,000 or less, preferably 50 to 600, reaction temperature is 140 to 260 ° C., and reaction pressure is 30 to 120 atmospheres. It has the effect that 1,4-butanediol can be manufactured from maleic acid ester stably for a long period of time without performing a reactivation operation of a catalyst at any time. In addition, the hydrogenation catalyst mainly composed of copper stabilized with silica used in the present invention does not use chromium, thereby minimizing the environmental load of the spent catalyst.

Claims (7)

A method for preparing 1,4-butanediol, comprising hydrogenating maleic acid ester in the presence of a catalyst represented by formula (1): Formula 1 CuO (a) MnO ₂ (b) M (c) SiO ₂ (d) Where a, b, c and d are percentages by weight, a is 40 to 90, b is 0.15 to 5, c is 0.001 to 5, d is 5 to 50, M represents an oxide of at least one metal element selected from zinc (Zn), platinum (Pt), palladium (Pd), rhenium (Re), ruthenium (Ru), and rhodium (Rh). The method of claim 1, The catalyst is activated by hydrogen or hydrogen-containing gas at 100 to 250 ° C. for about 1 to 60 hours, and then used in a hydrogenation reaction. The method of claim 1, The hydrogenation reaction is carried out at a temperature of 140 to 260 ℃ under a pressure of 30 to 120 atmospheres. The method of claim 1, Wherein the hydrogenation reaction is carried out under conditions in which the weight hourly space velocity (WHSV) of the maleic acid ester is 0.1 to 2.0 hr ⁻¹ and the molar ratio of hydrogen to maleic acid ester is 50 to 600: 1. The method of claim 1, The maleic acid ester is selected from dimethyl maleate, diethyl maleate, dipropyl maleate, diisopropyl maleate and dibutyl maleate. The method of claim 1, The maleic acid ester is dissolved in alcohol at a concentration of 20 to 80% by weight and then introduced into the hydrogenation reaction. The method of claim 6, And the alcohol has an alkyl group corresponding to the alkyl group of maleic acid ester.