KR101088100B1 - Method for preparing gamma butyrolactone by hydrogenation of palladium supported catalyst supported on alumina control gel carrier with controlled acid properties and succinic acid using the catalyst - Google Patents

Abstract

The present invention relates to a palladium supported catalyst supported on an alumina control gel carrier with controlled acid properties and a method for preparing gamma butyrolactone by hydrogenation of succinic acid using the catalyst, and more specifically, to gamma butyro from succinic acid. As a supported catalyst for producing lactone, the supported catalyst is prepared by gelation of an aluminum precursor by sol-gel method and then heat treatment, with an average pore size in the range of 2 nm to 10 nm, and a surface area of 100 m ² / g to 300 m ^In the range of ² / g, the Pd metal catalyst is supported in a ratio of 1 to 10 parts by weight based on 100 parts by weight of an alumina controlled Xerogel carrier having the acid point controlled by performing the heat treatment temperature in the range of 700 to 900 ° C. the acid amount of 50 to 300 μmol NH ₃ / catalyst weight range from after the supported catalyst and the acid characteristics, characterized in that the surface mount density of 0.5 to 1.5 μmol NH ₃ / m ² range adjustment With alumina control relates to a palladium-supported catalyst and a method of manufacturing a gamma butyrolactone by hydrogenation of succinic acid using the catalyst supported on the carrier gel. When the hydrogenation reaction of succinic acid in the liquid phase using the catalyst of the present invention can achieve a higher yield of gamma butyrolactone than the conventional commercially supported alumina supported catalyst, and separate purification process of the succinic acid recycled by the biorefinery process Butyrolactone can be prepared without going through.

Description

Palladium-supported catalyst supported on alumina-controlled gel carrier with controlled acid properties and method for producing gamma butyrolactone by hydrogenation of succinic acid using the above catalyst -BUTYROLACTONE BY HYDROGENATION OF SUCCINIC ACID USING SAID CATALYST}

The present invention relates to a palladium supported catalyst supported on an alumina control gel carrier with controlled acid properties and a method for preparing gamma butyrolactone by hydrogenation of succinic acid using the catalyst, and more specifically, to gamma butyro from succinic acid. As a supported catalyst for producing lactone, the supported catalyst is prepared by gelation of an aluminum precursor by sol-gel method and then heat treatment, with an average pore size in the range of 2 nm to 10 nm, and a surface area of 100 m ² / g to 300 m ^In the range of ² / g, the Pd metal catalyst is supported in a ratio of 1 to 10 parts by weight based on 100 parts by weight of an alumina controlled Xerogel carrier having the acid point controlled by performing the heat treatment temperature in the range of 700 to 900 ° C. the acid amount of 50 to 300 μmol NH ₃ / catalyst weight range from after the supported catalyst and the acid characteristics, characterized in that the surface mount density of 0.5 to 1.5 μmol NH ₃ / m ² range adjustment With alumina control relates to a palladium-supported catalyst and a method of manufacturing a gamma butyrolactone by hydrogenation of succinic acid using the catalyst supported on the carrier gel.

Gamma butyrolactone (γ-butyrolactone (GBL)) is used in the pharmaceutical industry in a number of fields, including reactive intermediates and paint solvents, and its market is steadily increasing. Since anhydride (maleic anhydride) is used as a raw material, it is urgent to replace the raw material. Succinic acid (SA) is an environmentally friendly energy material of the future that can be regenerated in biorefinery processes of wood waste biomass, and its interest is attracting attention, and it can be converted into useful compounds such as gamma butyrolactone through hydrogenation. Platform compound.

As a process for producing gamma butyrolactone, two commercially available processes have been known, namely, Reppe Process and Davy McKee Process using a copper catalyst. The Reppe Process, which produces gamma butyrolactone by dehydrogenation of 1,4-butanediol, is the first commercially available process for producing gamma butyrolactone, which is traditionally used in the US and Europe. Although it is a process that is being processed, the economic situation is losing due to the sharp increase in the price of 1,4-butanediol as a raw material, and there is a limitation that 1,4-butanediol is manufactured from formaldehyde, which is a hazardous substance. Since maleic anhydride can be produced at low cost through partial oxidation of n-butane, Davy McKee Process for producing gamma butyrolactone through hydrogenation of maleic anhydride as a raw material in Japan etc. Although it has been commercialized, this also has problems such as increased raw material cost, high temperature and high pressure reaction conditions, environmental pollution due to the generation of various by-products (furan tetrahydrogen, propionic acid, propanol, butanol, butyric acid, etc.).

These problems are due to the fact that the raw materials of the gamma butyrolactone manufacturing process are petrochemical products, and there is an urgent need to develop eco-friendly alternative processes and technologies due to global environmental regulations and rising prices due to oil price fluctuations. Accordingly, succinic acid is attracting attention as a platform compound capable of producing gamma butyrolactone, and it is an intermediate that can replace maleic anhydride, and maleic anhydride produced from butane by developing a new fermentation strain production process to date. The competition has reached a stage where it is possible.

The conversion of succinic acid into useful C4 compounds via hydrogenation has been reported in several literatures, but only minor studies of maleic anhydride and maleic acid hydrogenation processes have been conducted, but there have been few examples of applying detailed principles and mechanisms. . 1 shows a reaction mechanism in which gamma butyrolactone is prepared through hydrogenation from succinic acid. Succinic acid is first converted to succinic anhydride (SAN) through dehydration, followed by a continuous reaction in which the C = O bond of succinic anhydride is hydrogenated. Examples of conversion of succinic anhydride include hydrogenation of succinic anhydride using a palladium catalyst studied in Japan [T. Fuchikami, N. Wakasa, D-H. He, T. Miyake, T. Okada, A. Fujimura, H. Sasakibara, Y. Kanou, T. Saito, US Patent No. 5,502, 217, Examples of hydrogenation of succinic anhydrides using copper-chromium catalysts [U. Herrmann, G. Emig, Ind. Eng. Chem. Res., 36, 2885 (1997)]. However, in order to produce gamma butyrolactone through hydrogenation of succinic acid, succinic acid has to undergo a cyclization process in which succinic acid is converted into succinic anhydride. More difficult. In addition, hydrogenation of succinic acid is a case of hydrogenation of succinic acid of DuPont using ruthenium-cobalt catalyst [R.M. Deshpande, V.V. Buwa, C.V. Rode, R. V. Chaudhari, P.L. Mills, Catal. Commun., Vol. 3, p. 269 (2002)] and examples of hydrogenation of succinic acid using noble metal catalysts supported on carbon carriers [R.Luque, J.H. Clark, K. Yoshida, P.L. Gai, Chem. Commun., P. 5305 (2009)]. However, only a few of the precious metals have been considered in the hydrogenation of succinic acid, but they are still in the early stages of R & D.

As such, the catalysts and conversion processes used in the commercialization process for producing gamma butyrolactone from succinic acid, which can replace maleic anhydride, are very insignificant. Therefore, the yield of high gamma butyrolactone is increased by applying the detailed principles and mechanisms. Developing catalysts and process systems that can achieve this has important technical and economic significance. In addition, in order to reduce the cost of separation and purification, which accounts for more than 60% of the manufacturing cost of waste succinic acid recycled in the biorefinery process, by-products such as acetic acid without separating and purifying the by-products of the waste succinic acid production and fermentation process separately. The study of producing gamma butyrolactone by direct hydrogenation of succinic acid containing the product also has significant economic significance.

Accordingly, the present inventors have focused on the fact that the hydrogenation reaction for producing gamma butyrolactone from succinic acid is a continuous reaction as a result of research efforts to overcome the problems of the prior art and to improve the economics. As described above, succinic acid is first converted into succinic anhydride through dehydration, and secondly, a continuous reaction in which the C = O bond of succinic anhydride is hydrogenated. Since the succinic anhydride produced in the first dehydration reaction is easily converted to succinic acid when it meets the produced water, the succinic anhydride is converted to gamma butyrolactone only when it is adsorbed at the active point of palladium before reacting with water. Therefore, it is necessary to have a dual function catalysis that functions as an acid catalyst in the first reaction and a metal catalyst in the second reaction, and when these two functions are optimally combined, a high yield of gamma butyrolactone is achieved. Can be.

The present inventors have recently developed a process for producing gamma butyrolactone from succinic acid using a palladium supported catalyst supported on an alumina control gel carrier having medium porosity using the sol-gel method [Korean Patent Application No. 2009 -0131487]. The alumina control gels prepared using the sol-gel method exhibit various acid properties depending on the preparation temperature, and can act as excellent bifunctional catalysts when used in an optimal combination with noble metal catalysts. In addition, since the alumina control gel carrier has excellent physicochemical properties and a thermochemically stable structure, it has a high catalyst regeneration rate in the liquid phase hydrogenation of succinic acid at high temperature and high pressure.

Accordingly, an object of the present invention is to provide a precious metal supported catalyst in which the acid property of the medium pore alumina control gel carrier and the hydrogenation activity of the metal are controlled in an optimal combination, which has high chemical stability, strong durability, excellent physical properties, and medium size pores. The palladium supported catalyst and the catalyst supported on the alumina control rosette carrier which controlled the acid characteristics of the bifunctional catalyst for producing gamma butyrolactone utilizing the advantages of the acid properties and the precious metals of the alumina controlled rosette carrier It is to provide a method for producing gamma butyrolactone by hydrogenation.

In order to achieve the above technical problem, the present invention is a supported catalyst for the production of gamma butyrolactone from succinic acid, the supported catalyst is prepared through the heat treatment after gelling the aluminum precursor by the sol-gel method, the average pore size is 2nm 100 nm by weight of the alumina control rogel carrier, which has a range of from 10 nm and a surface area of 100 m ² / g to 300 m ² / g, wherein the acid point is adjusted by performing the heat treatment temperature in the range of 700 to 900 ° C. Pd metal catalyst is supported at a ratio of 1 to 10 parts by weight with respect to the acid content of the catalyst after loading, 50 to 300 μmol NH ₃ / catalyst weight range and surface acid density is 0.5 to 1.5 μmol NH ₃ / m ² Provided is a palladium supported catalyst supported on an alumina control gel carrier having an acid property adjusted thereto.

In addition, the present invention provides a method for producing gamma butyrolactone by hydrogenation of succinic acid comprising the step of reacting succinic acid or succinic anhydride in the presence of the catalyst at a temperature in the range of 150 to 300 ℃ and a pressure in the range of 40 to 100 bar. do.

According to the present invention, the palladium-supported catalyst supported on the controlled alumina control gel having the acid property developed according to the present invention is optimally combined with the acid property of the carrier and the hydrogenation activity of palladium when the hydrogenation reaction of succinic acid is carried out in the liquid phase. A high yield of gamma butyrolactone can be achieved, and a catalytic process that is thermochemically stable and has high reuse rates can be performed. In addition, gamma butyrolactone may be prepared without undergoing a separate purification process of succinic acid (hereinafter referred to as waste succinic acid) regenerated by a biorefinery process.

1 is a reaction mechanism in which gamma butyrolactone is prepared through hydrogenation from succinic acid.
FIG. 2 shows (X) of the palladium supported catalysts (Pd / AX700, Pd / AX750, Pd / AX800, Pd / AX850, Pd / AX900) supported on the alumina control rogel carrier for each firing temperature prepared in Example 1. -Ray diffraction spectrum analysis
FIG. 3 shows the result of nitrogen adsorption-desorption analysis of the palladium supported catalyst supported on the alumina control rogel carrier prepared according to the firing temperature prepared in Example 1
4 is a hydrogenation principle of succinic acid according to the acid density and palladium active site in the present invention

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The palladium supported catalyst (hereinafter, also referred to as palladium / alumina controlled gel catalyst in short form) supported on the alumina control gel of the present invention is prepared through gelation of an aluminum precursor by a sol-gel method, followed by heat treatment, and an average pore. Size ranges from 2 nm to 10 nm, surface area in the range of 100 m ² / g to 300 m ² / g, the alumina controlled Xerogel carrier adjusted to the acid point by performing the heat treatment temperature in the range of 700 to 900 ℃ Pd metal catalyst is supported at a ratio of 1 to 10 parts by weight with respect to 100 parts by weight, and the amount of the catalyst after loading is in the range of 50 to 300 μmol NH ₃ / catalyst weight and the surface acid density is in the range of 0.5 to 1.5 μmol NH ₃ / m ² It is characterized by that.

After preparing the alumina control gel having medium pores by sol-gel method, it is useful to improve the acid properties of the carrier (catalyst) by controlling the calcination temperature and usefully improve it as a carrier for hydrogenation dehydration. Preparation of palladium / alumina controlled rogel catalyst supporting palladium as an active metal on the support and when applied to gamma butyrolactone conversion of succinic acid, the acid properties of the carrier and the hydrogenation activity of palladium are optimally combined to provide gamma butyrolactone. It shows a particularly good effect when prepared.

The palladium / alumina-controlled gel catalyst of the present invention is a catalyst carrying palladium after calcining an alumina-controlled gel support having a pore size in the range of 2 to 15 nm at a temperature in the range of 700 ° C. to 900 ° C. In order for the alumina control gel support to exhibit excellent acid properties as a catalyst carrier, the alumina control gel was calcined in the range of 700 ° C. to 900 ° C., and the 2θ characteristic peak of the X-ray diffraction spectrum was 35 °. To 38˚, 45˚ To 47˚, 66˚ to 68˚ The supported catalyst prepared at the temperature includes a palladium supported catalyst supported on an alumina controlled rogel carrier having a high surface acid density of 0.5 to 1.5 μmol NH ₃ / m ² . . If the calcination temperature of the alumina control gel support is less than 700 ° C., the amorphous alumina phase does not show strong acid properties, and if it exceeds 900 ° C., the crystalline alpha alumina phase also exhibits strong crystalline alpha alumina phase, resulting in weak acid properties. Since problems arise, it is preferable to maintain the above range to form an alumina phase having a high surface acid density.

Looking at the method for producing a palladium / alumina control gel catalyst according to the present invention in more detail as follows. First, the aluminum precursor is dissolved in an alcohol solvent heated to 50 ° C. to 100 ° C., and then partially hydrated by adding water and an acid to prepare an alumina sol. The aluminum precursor is generally used in the art, but is not particularly limited, and aluminum alkoxide, aluminum acetyl acetate, and alumina sol having an alkoxy group having 1 to 5 carbon atoms may be used. The alcohol solvent is generally used in the art and is not particularly limited. Specifically, alcohols having 1 to 6 carbon atoms may be used. The solvent is used in the range of 1.5 to 2.5 with respect to the aluminum precursor. If the amount is less than 1.5, the solvent is not sufficient to disperse the aluminum precursor. If the solvent exceeds 2.5, the solvent may not be formed smoothly. It is desirable to maintain.

The water and acid used in the reaction are used in the range of 0.3 to 0.5 weight ratio and 0.04 to 0.05 weight ratio, respectively, with respect to the added aluminum, and the amount of the acid and the acid used is a proper amount for partially hydrating to prepare an alumina transparent sol. Next, after cooling the prepared alumina sol, water is added to prepare an alumina gel. The water is used in the weight ratio range of 1.0 to 1.2 with respect to the added alumina. If the amount is less than 1.0, condensation of the structure occurs during gel formation, and the solvent is evaporated from the pores during the aging process. In this case, it is preferable to maintain the above range because gel formation proceeds too fast to obtain a uniform gel.

Next, the prepared alumina gel is aged and dried. At this time, aging is carried out at room temperature for 2 to 8 days, preferably 3 to 7 days. In addition, drying after aging is dried for 24 to 48 hours at 70 ℃ to 100 ℃, preferably 70 ℃ to 90 ℃.

Next, the dried alumina gel is calcined at a temperature in the range of 700 ° C to 900 ° C, preferably 800 ° C to 850 ° C, to prepare an alumina control gel.

Next, after impregnating the palladium precursor in the range of 1 to 10 parts by weight based on 100 parts by weight of the prepared alumina control gel, dried at a temperature of 80 ° C. to 150 ° C. for at least 12 hours to remove all moisture, and then 300 ° C. To 700 [deg.] C., preferably at 400 [deg.] C. to 500 [deg.] C. for at least 3 hours to prepare a palladium / alumina controlled gel catalyst. In the present invention, the basic material used as a palladium precursor for preparing a catalyst is palladium nitrate, palladium chloride, palladium acetate, which is well dissolved in water and well decomposed into a metal form by heat reduction. , Amine complex and the like may be used, and preferably, palladium nitrate, which is easily heat-reduced at low temperature, may be used. If the amount of the supported palladium precursor is less than 1 part by weight based on 100 parts by weight of the alumina control gel, the amount of palladium is small to show the required degree of hydrogenation reaction activity. It is preferable to maintain the above range because the activity of the reaction is lowered and the economical efficiency is lowered due to the high price of the palladium precursor.

On the other hand, the present invention provides a method for producing gamma butyrolactone by hydrogenation of succinic acid, characterized in that the hydrogenation reaction is carried out in the presence of the palladium / alumina control rogel supported catalyst. . The process is generally carried out in a batch reaction at a high temperature and pressure range, in particular at a temperature of 150 ℃ to 400 ℃ and a pressure range of 30 bar to 200 bar, the main process conditions are 300 ℃, 100 bar or less It is economically desirable to carry out at a mild temperature and pressure range of. Therefore, in the present invention, the hydrogenated reaction of waste succinic acid was carried out at a temperature range of 240 ° C. and a pressure of 60 bar. The reaction can be performed even at a temperature of 200 ° C. or below and a pressure of 40 bar or less. It takes longer, so setting the appropriate temperature, pressure, and time is an important factor in controlling the productivity of gamma butyrolactone.

In addition, in the present invention, the process of converting the waste succinic acid to gamma butyrolactone is carried out in consideration of the conversion rate and the reactor volume in the liquid phase, and since it is a liquid phase process that does not overheat, it is easy to regenerate the catalyst because there is no deterioration of catalyst activity due to coke formation. Do. This catalytic reaction process is a heterogeneous reaction using a solid catalyst by dissolving the reactant waste succinic acid in a liquid solvent.The solvent is an aromatic substance such as benzene, toluene and xylene, aliphatic alcohol such as methanol, ethanol, And a wide range of inert solvents, such as tetrahydrofuran, gamma butyrolactone, and dioxane, can be used. In the commercialization process, when the process product, tetrahydrofuran or gamma butyrolactone, is used as a solvent, there is an advantage that separation and solvent removal are not necessary depending on the purpose, but in this process, gamma butyrolactone and a byproduct tetrahydrofuran, 1, In order to accurately measure the production of 4-butanediol and the like, 1,4-dioxane was used as a solvent. Stirring of the reactor was carried out using a magnetic drive, and the stirring speed was generally 300 rpm to 1000 rpm, but in the region where the mass transfer at the interface between hydrogen and the reactant is maximized in consideration of the state of the catalyst and the viscosity of the solvent. It should preferably be carried out at the minimum agitation rate of the areas where mass transfer is at a premium, taking into account the process costs.

In an embodiment of the present invention, waste succinic acid is artificially reproduced by mixing succinic acid with acetic acid which is inevitably generated during succinic acid production from the biorefinery process as a reactant. As a by-product of waste succinic acid fermented from glucose in the biorefinery process, it has been reported that the weight ratio of acetic acid and succinic acid can be as high as 1: 7 [C. Du, S.K.C. Lin, A. Koutinas, R. Wang, C. Webb, Appl. Microbiol. Biot., Vol. 76, p. 1263 (2007)], and also, byproducts are a very important issue in the fermentation process, and the proportion of byproducts is expected to decrease further as active research and development proceed. Therefore, the reaction mixture of acetic acid and succinic acid used in the present invention is preferably used in the weight ratio of acetic acid and succinic acid in the range of 1: 5 to 1:10. On the other hand, the amount of the reactants is suitable to more than twice the amount of the catalyst, the specific amount is preferably maintained in a suitable ratio in consideration of the maintenance cost, productivity, catalyst regeneration efficiency, etc. in the actual process.

Hereinafter, the present invention will be described in more detail with reference to Preparation Examples and Examples.

Preparation Example 1 and Comparative Example 1: Preparation of Palladium Supported Catalyst Supported on Medium Porosity Alumina Controlled Rose Carrier and Alumina Controlled Roselle Carrier with Adjusted Acid Properties

Medium porosity alumina control gel catalysts were prepared using the sol-gel method. First, 60 ml of ethanol was heated to 80 DEG C while stirring using a magnetic stirrer, and then 7 g of aluminum sec-butoxide (Aldrich), an aluminum precursor, was dissolved in a heated ethanol solvent. Thereafter, while maintaining the solution at 80 ° C., a partial hydration reaction was carried out while gradually adding a ethanol / nitric acid / water (40 ml / 0.1 ml / 0.3 ml) mixed solution to the solution, and in a few minutes, a uniform and transparent alumina sol (sol ) Was prepared. After cooling the obtained sol (Sol) to room temperature, a mixture of ethanol / water (5 ml / 0.6 ml) was slowly injected to obtain an alumina gel through a hydration and condensation reaction, which was aged at room temperature for 5 days. . Thereafter, the aged gel was dried in a drier maintained at 100 ° C. for 24 hours to obtain amorphous alumina xerogel. The amorphous alumina control rogel was 700 ° C., 750 ° C., 800 ° C., and 850, respectively. The acid characteristics were adjusted by firing at a temperature of 900C and 900C. The alumina control gel carrier prepared above was described as AX700, AX750, AX800, AX850, AX900, respectively. In this case, the number means the firing temperature in degrees Celsius.

Thus, a palladium supported catalyst was prepared by supporting palladium on alumina control gel carrier calcined at various temperatures. First, palladium nitrate, a precursor of palladium metal, is dissolved in distilled water. At this time, the amount of water was kept at a minimum amount of 0.1 ml per g of catalyst. Five kinds of alumina control gels (AX700, AX750, AX800, AX850, AX900) were calcined so that the weight ratio of the palladium to the weight of the final supported catalyst was 1: 0.05 in the solution thus prepared and impregnated by applying a physical force. . At this time, the incipient wetness method was used to adjust the water so that water was added to the water so that the alumina was moist. Through this process, a palladium-supported alumina-controlled gel catalyst was prepared. Then, the impregnated palladium / alumina-controlled gel sample was dried at 120 ° C. for at least 24 hours to remove all moisture, and then the catalyst was heated in a high-temperature electric furnace. The nitrate group was removed by calcination at about 4 hours or more. The catalysts prepared above were described as Pd / AX700, Pd / AX750, Pd / AX800, Pd / AX850, and Pd / AX900, respectively. Then, the prepared catalysts were subjected to sufficient reduction treatment for 3 hours under a 300 ° C. hydrogen atmosphere.

X-ray diffraction spectrum analysis results of the palladium supported catalysts (Pd / AX700, Pd / AX750, Pd / AX800, Pd / AX850, Pd / AX900) supported on the alumina control gel carrier prepared by firing temperature Summarized in 2. Each of the supported catalysts had a 35 [theta] characteristic peak in the X-ray diffraction spectrum of 35 DEG. To 38˚, 45˚ To 47˚, 66˚ To 68˚ Since it appears well in the range of, it can be confirmed that the acid point contains a gamma alumina phase rich in acid. In addition, all catalysts have a palladium-specific metal peak of 2θ = 40˚. Observed in the vicinity, it can be seen that the active point was well developed as a hydrogenation catalyst after the reduction treatment.

On the other hand, specific surface area measurement experiments of palladium supported catalysts (Pd / AX700, Pd / AX750, Pd / AX800, Pd / AX850, Pd / AX900) supported on the alumina control gel carrier by firing temperature Palladium dispersion was measured and measured through hydrogen adsorption experiment. The results are summarized in Table 1 below.

Pd / AX700 Pd / AX750 Pd / AX800 Pd / AX850 Pd / AX900 Specific surface area
(m ² / g-cat.) 270 237 174 162 146 Total acid
(μmol NH ₃ / g-cat.) 202 205 207 213 140 Surface acid density
(μmol NH ₃ / m ² ) 0.75 0.87 1.19 1.32 0.96 Palladium dispersion
(%) 22.3 21.7 21.6 22.2 21.1

As shown in Table 1, the palladium supported catalysts supported on the alumina control gel carrier prepared for each firing temperature tended to have a lower specific surface area as the firing temperature increased. In the case of total acid amount, it was shown that the tendency to increase slightly as the firing temperature was increased, but then decreased at the carrier firing temperature of 900 ℃. This phenomenon shows that the 2θ characteristic peak of the X-ray diffraction spectrum is 30˚. To 35˚ As the delta or setter alumina phase appears in between, the acid properties can be reduced. In general, the acid properties of the alumina control gels prepared by the sol-gel method exhibit the most abundant acid properties when the alumina phase exhibits the gamma phase, showing excellent activity in the acid catalyst reaction [GK Chuah, S. Jaenicke, TH Xu, Micropor. Mesopor. Mater., Vol. 37, p. 345 (2000) / KM Cho, S. Park, JG Seo, MH Youn, I. Nam, S.-H. Baeck, JS Chung, K.-W. Jun, IK Song, Chem. Eng. J., Vol. 146, p. 307 (2009)], as the firing temperature is known to increase the surface acid density [GS Walker, DR Pyke, CR Werrett, E. Williams, AK Bhattacharya, Appl. Surf. Sci., 147, p. 228 (1999). The surface acid density is a value obtained by dividing the total acid content by the specific surface area, which indicates the density per unit area of the acid point, which acts primarily on the dehydration reaction occurring in the hydrogenation reaction of succinic acid to promote the production of succinic anhydride. The supported catalyst also increased the surface acid density due to the decrease of specific surface area as the firing temperature of the carrier increased in the alumina range of gamma phase (Pd / AX700, Pd / AX750, Pd / AX800, Pd / AX850), and the alumina on delta or setter In the phased Pd / AX900 catalyst, the surface acid density decreased as the total acid amount decreased but the specific surface area decreased. Therefore, it can be seen that it is possible to adjust the acid characteristics according to the firing temperature of the alumina control gel support, and when the acid catalyst activity and the activity of the metal catalyst of the supported catalyst act in the optimum ratio, the acid catalyst function and the metal for the hydrogenation reaction It was confirmed that the catalytic function can act as an efficient dual function catalyst for the conversion reaction to gamma butyrolactone of succinic acid, which is required at the same time.

On the other hand, the dispersities of palladium were all about 22% and showed almost similar values, because the weight ratio of palladium to the supported catalyst was small, so the dispersibility did not depend on the pore structure or specific surface area of the carrier. .

Figure 3 shows the results of nitrogen adsorption-desorption analysis of the palladium supported catalyst supported on the alumina control gel carrier prepared by firing temperature. The nitrogen adsorption-desorption analysis curves of the palladium supported catalysts supported on the alumina control gel carrier prepared by firing temperature showed typical Type-IV isotherms and type-H2 type hysteresis. Type-H2 type hysteresis means that ink bottle-shaped medium pores with large pore volume and small pore inlet size were developed on the alumina control gel carrier. In addition, the average pore size distribution graph also confirms that all catalysts exhibit an average pore size of 3 to 7 nm. These results also indicate that all medium pores of the catalysts developed in the present invention were well developed.

(Use) Example 2 and Comparative Example 2: Waste on palladium supported catalyst (Pd / AX700, Pd / AX750, Pd / AX800, Pd / AX850, Pd / AX900) supported on the alumina control gel carrier prepared by firing temperature Preparation of Gamma Butyrolactone by Hydrogenation of Succinic Acid

(Preparation) The production reaction of gamma butyrolactone by hydrogenation of waste succinic acid was carried out using a palladium supported catalyst supported on the alumina control gel carrier prepared for each firing temperature described above in Example 1 and Comparative Example 1. The selectivity, conversion and yield of the reaction were calculated as in Equations 1 to 4 below and the reaction results are shown in Table 2.

Gamma butyrolactone
Selectivity (%) Succinic anhydride
Selectivity (%) Succinate Conversion Rate (%) Gamma butyrolactone
Yield (%) Pd / AX700 83 2 53 44 Pd / AX750 80 4 58 47 Pd / AX800 72 12 67 48 Pd / AX850 65 17 79 51 Pd / AX900 76 5 63 48

The conversion reaction of waste succinic acid was made in the liquid state and carried out using a batch reactor. For the reaction, an autoclave reactor was charged with 0.2 g of catalyst, 0.5 g of succinic acid, 0.1 g of acetic acid as a by-product of waste succinic acid with 50 ml of 1,4-dioxane solvent, and then flowed with nitrogen 3,4 times. Remove oxygen from Then, when hydrogen is injected to a pressure of about 30 bar, it is heated at a temperature increase rate of 10 ℃ / min to the reaction temperature. When the reaction temperature is reached, the pressure is raised to 60 bar again using hydrogen, and this time is used as the reaction start time. The total reaction time was 4 hours, the stirring speed was performed at 500 rpm without influence of mass transfer, and the reaction temperature was performed at 240 ° C., respectively. After the reaction, the temperature was cooled to room temperature, the pressure was removed, and the catalyst and the liquid product were separated by filtration and analyzed by gas chromatography (GC). As a by-product, succinic anhydride, propionic acid, butyric acid and 1,4-butanediol were mainly produced.

As shown in Table 2, the succinic acid conversion rate of the palladium supported catalyst (Pd / AX700, Pd / AX750, Pd / AX800, Pd / AX850, Pd / AX900) supported on the alumina control gel carrier prepared by firing temperature according to the present invention. The yield of and gamma butyrolactone was high in the order of Pd / AX850> Pd / AX800> Pd / AX900> Pd / AX750> Pd / AX700.

This is because, as shown in Table 1, all of the catalysts produced in the present invention showed a similar dispersion of palladium, whereas the acid density showed different values. Similar dispersities mean that the same number of palladium active sites is the same because each alumina control gel carries the same amount of palladium. When the number of palladium active points on the surface is the same and the acid density increases, the unit area including the number of palladium active points equal to the number of the same acid points on the surface of the carrier becomes smaller, so that the average distance between the palladium active points and the acid point becomes closer. Therefore, the succinic anhydride produced through the acid point of the alumina control rogel is rapidly adsorbed to the active site of palladium without encountering water, thereby increasing the probability of conversion to gamma butyrolactone. On the contrary, when the number of palladium active points on the surface is the same but the acid density decreases, the average distance between the palladium active point and the acid point is increased because the unit area including the number of the same palladium active points on the surface of the carrier increases. As a result, the succinic anhydride converted by the succinic acid adsorbed at the acidic point has a relatively low probability of encountering the palladium active site and a high probability of encountering the water produced in the dehydration reaction, resulting in a lower conversion rate compared to the high surface acid density. 4). Therefore, in the present invention, it can be seen that the Pd / AX850 catalyst among the prepared palladium supported catalysts exhibits the best surface acid density, which acts as a very efficient catalyst for the gamma butyrolactone conversion reaction of succinic acid.

Example 3: Reuse of Pd / AX850 Catalyst in Preparation of Gamma Butyrolactone by Hydrogenation of Succinic Acid

Using the Pd / AX850 catalyst showing the best yield of gamma butyrolactone in Example 2 and Comparative Example 2, a catalyst regeneration experiment was carried out at 240 ° C. for 4 hours in the hydrogenation reaction of spent succinic acid. . The catalyst used was separated by filtration, calcined at 400 ° C., higher than the boiling point of the products, to remove impurities, and then sufficiently reduced for 3 hours using hydrogen at 300 ° C., and the results are shown in Table 3. .

As a result of reusing the used Pd / AX850 catalyst, all showed similar activity as the new catalyst, and elemental analysis after the reaction of the used catalyst also showed no elution of palladium. Therefore, it can be seen that the palladium supported catalyst prepared in the present invention is a catalyst having stability and excellent reuse rate in the hydrogenation reaction of waste succinic acid carried out at high temperature and high pressure.

The embodiments of the present invention described above should not be construed as limiting the technical idea of the present invention. The scope of protection of the present invention is limited only by the matters described in the claims, and those skilled in the art will be able to modify the technical idea of the present invention in various forms. Therefore, such improvements and modifications will fall within the protection scope of the present invention, as will be apparent to those skilled in the art.

Claims (2)

As a supported catalyst for producing gamma butyrolactone from succinic acid,
The supported catalyst is prepared by heat treatment after gelling the aluminum precursor by sol-gel method, the average pore size is in the range of 2nm to 10nm, the surface area is in the range of 100 m ² / g to 300 m ² / g, the heat treatment Pd metal catalyst is supported at a ratio of 1 to 10 parts by weight based on 100 parts by weight of an alumina controlled Xerogel carrier having a temperature adjusted in the range of 700 to 900 ° C., and the acid amount of the catalyst is 50 to 300 after loading. A palladium supported catalyst supported on an alumina controlled rogel carrier with an adjusted acid property, characterized in that the range of μmol NH ₃ / catalyst weight and the surface acid density ranges from 0.5 to 1.5 μmol NH ₃ / m ² . A method for preparing gamma butyrolactone by hydrogenation of succinic acid comprising reacting succinic acid or succinic anhydride in the presence of the catalyst of claim 1 at a temperature in the range of 150 to 300 ° C. and a pressure in the range of 40 to 100 bar.

Images