KR20140063209A - Novel metal catalyst supported on cation-exchanged heteropolyacid-impregnated activated carbon aerogel bearing sulfonic acid and decomposition method of lignin compounds using said catalyst - Google Patents

Abstract

The present invention relates to a catalyst which produces an aromatic family by selectively decomposing a carbon-oxygen-carbon bond in an internal combination inside lignin, and is denoted by chemical formula: M/QxH3.0-xPW12O40/ACA-SO3H (M is one or more precious metal selected from the group consisting of palladium, rhodium, ruthenium, and platinum; QxH3.0-xPW12O40 is positive ion-exchanged heteropolyacid; ACA is active carbon aerogel; and -SO3H is a sulfonic acid group). The catalyst is produced by depositing 1-30 wt% of one or more precious metal selected from the group consisting of palladium, rhodium, ruthenium, and platinum based on the weight of the active carbon aerogel, on a carrier obtained by impregnating 5-70 wt% of positive ion-exchanged heteropolyacid on the carbon aerogel containing sulfonic acid which is produced by reacting high concentration sulfuric acid and the active carbon aerogel and combining 0.5-5 wt% of sulfonic acid on the surface of the active carbon aerogel based on the weight of the active carbon aerogel.

Description

TECHNICAL FIELD [0001] The present invention relates to a noble metal catalyst supported on an activated carbon aerogel including a sulfonic acid-impregnated sulfonic acid-impregnated heteropolyacid with a cation-substituted heteropoly acid, and a method for decomposing a lignin compound using the catalyst. BACKGROUND ART < RTI ID = 0.0 & SAID CATALYST}

The present invention relates to a noble metal catalyst supported on a sulfonic acid-containing activated carbon aerogels impregnated with a cation-substituted heteropoly acid and a method for decomposing lignin compounds using the catalyst, and more particularly to a method for decomposing a carbon- A catalyst for decomposition to produce aromatics, said catalyst having the formula M / Q _x H _3.0-x PW ₁₂ O ₄₀ / ACA-SO ₃ H wherein M is a member selected from the group consisting of palladium, rhodium, ruthenium and platinum the more noble metal, Q _x H _3.0 PW ₁₂ O _40-x is a cation substituted heteropolyacid, Q is an alkali metal or ammonium ion, ACA is activated carbon airgel, and -SO ₃ H being expressed as a sulfonic acid group), a high concentration of After reacting sulfuric acid with activated carbon aerogels, sulfonic acid was added to the surface of activated carbon aerogels at a concentration of 0.5 to 5 wt% Based on the weight of the activated carbon aerogels, at least one noble metal selected from the group consisting of palladium, rhodium, ruthenium and platinum is added to the carrier impregnated with the activated heteropoly acid in the range of 5 to 70 wt% The present invention relates to a noble metal catalyst supported on activated carbon aerogels including a sulfonic acid-impregnated cation-substituted heteropoly acid-impregnated catalyst, and a method for decomposing lignin compounds using the catalyst.

The chemical industry, based on fossil fuels such as coal and oil, is changing its paradigm to biomass-based chemical industry due to the problem of rising prices due to depletion of fossil fuels and global warming caused by pollution in the air. The biomass-based chemical industry is attracting attention as an energy source that does not contribute to global warming because the cycle of carbon dioxide generated after use occurs over several months or years. However, biomass, such as starch and sugars, is an energy source, but at the same time plays an important role as a food resource. On the other hand, woody biomass is attracting attention as a material that does not compete with existing food resources. The woody biomass is composed of cellulose, hemicellulose and lignin. Cellulose and hemicellulose can be converted into high-value energy sources such as biodiesel and bioethanol by using a post-treatment process. On the other hand, lignin is used as a low-value-added fuel in combustion or power generation in the production process. However, since a large amount of aromatic material is contained in lignin, a technique of using aromatics generated by decomposing lignin as a chemical substance or a fuel additive is attracting attention.

The molecular weight and molecular weight distribution of lignin differ depending on the type of woody biomass and pretreatment conditions. However, as shown in FIG. 1, aromatic substances such as benzene and phenol are bonded with carbon-carbon (CC) bond and carbon- And is chemically very stable. Therefore, it is difficult to produce monomeric aromatic chemicals by decomposing and converting lignin, and the materials produced through the above process are less competitive than those produced by conventional petroleum refining. However, as oil prices have risen recently, it is expected that aromatic materials produced by decomposing lignin will be competitive, and research and development on lignin decomposition is actively underway.

Lignin is a polymeric material polymerized by conjugation of coniphenyl alcohol, cumaryl alcohol, and cinapyl alcohol with enzymes. Its structure is complex and diverse, and lignin degradation studies use model compounds that can easily express lignin structure. The lignin model compound is a beta carbon-oxygen-4 carbon (? -O-4) bond, an alpha carbon-oxygen-4 carbon (? Carbon-oxygen-5-carbon (4-O-5) bond and the like are mainly used (Non-Patent Document 1). In order to express the beta-carbon-oxygen-carbon bond showing the highest ratio of the lignin model compounds, phenethylphenyl ether is mainly used and the 4-O-5 bond showing the highest binding energy among the CO bonds in the lignin The 4-phenoxyphenol shown in Fig. 2 is mainly used as a lignin model compound.

The pyrolysis method, which directly decomposes lignin, decomposes lignin at high pressure and high temperature to produce aromatics. At 450 ° C and 100 atmospheres or higher, the conversion rate is about 20% or more. The reaction temperature and pressure are 450 ° C and 100 atm The conversion rate is 10% or less (Non-Patent Document 2). However, since pyrolysis has a problem of low yield while decomposing lignin at a high temperature and a high pressure, recently, the technology of high value of lignin using catalyst has attracted attention. The Lignol process developed by HRI (Hydrocarbon Research, Inc.) obtained an aromatic yield of about 30% or more by using iron, cobalt, molybdenum and nickel supported on alumina and silica as catalysts (Patent Document 1). The process of hydrogenolysis of lignin using a zeolite catalyst such as H-ZSM-5 involves a carbon-oxygen (CO) bond having a relatively weak bond and a carbon-carbon (CC) bond having a relatively strong bond in lignin . The catalyst performance in lignin decomposition using zeolite is strongly influenced by the structure and acid strength of zeolite (Non-Patent Document 3).

A technique for degrading lignin using cation-substituted heteropoly acids has been introduced as a method for selectively decomposing carbon (CO) bonds of lignin. Decomposition of lignin model compounds with cesium ion substituted heteropolyacid (Cs _2.5 H _0.5 PW ₁₂ O ₄₀ ) catalyst shows excellent lignin degradation efficiency of 80% and 60%, respectively, in conversion and main product yield. This method is useful for decomposing lignin because about 60 to 70% of carbon-oxygen bonds are distributed in lignin (Non-Patent Document 4, Patent Document 2). The noble metal supported on the cerium ion-substituted heteropoly acid has the effect of increasing the adsorption power on the acid catalyst surface of the carbon-oxygen (CO) bond of lignin to increase the conversion and yield (Non-Patent Document 5) (Patent Document 3).

The noble metal catalyst supported on activated carbon is also effective in decomposing lignin or lignin oligomers (Non-Patent Document 6). However, activated carbon is ineffective in decomposing lignin having a large molecular size because pores are distributed mainly in the range of 1 to 3 nm. Carbon aerogels are carbon compounds in which mesopores are developed. Pores are distributed in the range of 3-20 nm according to the production method. Accordingly, the present inventors have shown that a high conversion and yield can be obtained by decomposing lignin by using a palladium catalyst supported on activated carbon aerogels activated with phosphoric acid, the carbon aerogels in which mesopores are developed (Patent Document 4).

When activated carbonaceous aerosol activated by phosphoric acid is used as a lignin decomposition catalyst by treating a sulfonic acid with a sulfonic acid and then carrying a noble metal, the conversion and aromatic yield of the lignin model compound are increased compared with the noble metal supported on the activated carbon aerogels 7). In addition, decomposition of the lignin model compound by impregnating activated carbon aerogels with a cation-substituted heteropoly acid having excellent acid property in a solid acid catalyst and supporting the noble metal as a lignin model compound decomposition catalyst results in a conversion of 90% or more and an aromatic yield of 60% or more (Non-patent document 8).

1. US Patent 4,647,704 (D.J. Engel, K. Z. Steigleder) 1987. 2. Korean Patent Application 10-2010-0030562 (Song In-gyu, Park Hae-woong, Park Sun-young) 2010. 3. Korean Patent Application 10-2010-0066173 (In-Kyu Song, Hae-Woong Park, Sun-Young Park) 2010. 4. Korean Patent Application 10-2010-0097482 (In-Kyu Song, Hae-Woong Park, Sun-Young Park) 2010.

 1. J.B. Binder, M.J. Gray, J.F. White, Z.C. Zhang, J.E. Holladay, Biomass and Bioenergy Vol. 33, p. 1122 (2009).  2. P.F. Britt, A.C. Buchanan, E.A. Malcolm, J. Org. Chem. 60, p. 6523 (1995).  3. A. Oasmaa, R. Alen, Bioresource Tech. 45, p. 189 (1993).  4. H.W. Park, S. Park, D.R. Park, J.H. Choi, I.K. Song, Catal. Commun. 12 Volume 1 (2010).  5. H.W. Park, S. Park, D.R. Park, J.H. Choi, I.K. Song, Korean J. Chem. Eng. 28, 1177 (2010).  6. N. Yan, C. Zhao, P.J. Dyson, C. Wang, L.-T. Liu, Y. Kou, Chem. Shut up. Chem. Vol. 1, p. 626 (2008).  7. H.W. Park, U.G. Hong, Y.J. Lee, I.K. Song, Catal. Comm. 20 volume 89 pages (2012)  8. H.W. Park, U.G. Hong, Y.J. Lee, J.H. Choi, I.K. Song, Appl. Catal. A: Gen. 437-438 volume 112 pages (2012)

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above problems, and it is therefore an object of the present invention to provide a catalyst for producing a noble metal-supported catalyst on a mesoporous carbon carrier containing acid sites and to effectively decompose lignin having a relatively large molecular size The present invention provides a catalyst production method and a decomposition process technology capable of producing expensive aromatic compounds through development.

According to an aspect of the present invention, there is provided a catalyst for selectively decomposing a carbon-oxygen-carbon bond in an internal bond of lignin to produce an aromatic, wherein the catalyst has the formula M / Q _x H _3.0-x PW ₁₂ O ₄₀ / ACA-SO ₃ H wherein M is at least one noble metal selected from the group consisting of palladium, rhodium, ruthenium and platinum, Q _x H _3.0-x PW ₁₂ O ₄₀ is a cation-substituted heteropolyacid, Q is an alkali metal or Ammonium ion, ACA is an activated carbon aerogel, and -SO ₃ H is a sulfonic acid group), reacting a high concentration of sulfuric acid with activated carbon aerogels, and then bonding the sulfonic acid to the surface of the activated carbon aerogels at 0.5-5 wt% A carrier impregnated with a sulfonic acid-containing carbon aerogel with cation-substituted heteropoly acid in an amount of 5 to 70% by weight, based on the weight of the activated carbon aerogels, is impregnated with palladium, rhodium, ruthenium and platinum Wherein at least one kind of noble metal selected from the group consisting of the activated carbon aerogels is supported in an amount of 1 to 30% by weight based on the weight of the activated carbon aerogels, the noble metal catalyst supported on the activated carbon aerogels containing the sulfonic acid impregnated with the cation-substituted heteropoly acid .

In addition, the present invention relates to a process for producing activated carbon aerogels wherein the carbon aerogels produced by polymerizing Resocinol and formaldehyde are activated with one or more activating substances selected from the group consisting of potassium hydroxide, phosphoric acid, and zinc chloride, , Wherein the ratio of the resorcinol to the formaldehyde (R / F ratio) is in the range of 0.1 to 2.0 in molar ratio. The present invention provides a noble metal catalyst supported on activated carbon aerogels containing sulfonic acid impregnated with cation-substituted heteropoly acid.

The present invention also provides a method of decomposing a lignin model compound, which decomposes lignin under a pressure in the range of less than 300 ° C and hydrogen pressure of 50 atm or lower in the presence of the catalyst to produce an aromatic compound.

In the case of decomposing the lignin model compound using the noble metal catalyst supported on the activated carbon aerogels containing the sulfonic acid-containing sulfonic acid impregnated with the cation-substituted heteropolyacid of the present invention, the lignin pyrolysis method performed under the existing high temperature and high pressure condition (400 ° C., 50 atm) Oxygen and carbon bonds in the internal bond of lignin at low temperature and low pressure (200 ° C, 10 atmospheres) to produce aromatics such as benzene and phenol.

Figure 1 shows a lignin structure diagram illustrating internal lignin binding
FIG. 2 is a schematic diagram of a lignin model compound having a 4-carbon-oxygen-5-carbon (4-O-5)
Fig. 3 is a graph showing the results of the production process of activated carbon aerogels containing sulfonic acid and containing cationic substituted heteropoly acid and containing acid sites as prepared in Production Example 1, and the production process of palladium catalyst supported on active carbon aerogels including acid sites
FIG. 4 is a graph showing the results of measurement of a Pd / YCs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H, Y (weight average molecular weight) adsorbed on activated carbon aerogels containing a sulfonic acid produced in Production Example 1 and impregnated with cation-substituted heteropoly acid = 10, 15, 20, 25, and 30% by weight) Nitrogen adsorption / desorption curve
FIG. 5 is a graph showing the results of measurement of Pd / YCs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H, Y (weight average molecular weight) of the Pd / YCs supported on activated carbon aerogels containing a sulfonic acid produced in Production Example 1 and impregnated with cation-substituted heteropoly acid = 10, 15, 20, 25, and 30 wt%) XRD pattern
FIG. 6 is a graph showing the results of measurement of the activity of Pd / YCs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H, Y (solid content) in the activated carbon aerogels impregnated with cation- = 10, 15, 20, 25, and 30% by weight) as a result of decomposition of 4-phenoxyphenol
FIG. 7 is a graph showing the results of measurement of a Pd / YCs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H, Y = 10, 15, 20 , 25, and 30% by weight), the yield of the main product resulting from the decomposition of 4-phenoxy phenol
FIG. 8 is a graph showing the results of a Pd / 15Cs _2.5 H _0.5 PW ₁₂ O ₄₀ / Pd catalyst supported on activated carbon aerogels containing a sulfonic acid produced in Production Example 1 and Comparative Preparations 1 and 2 and impregnated with cation-substituted heteropolyacids, ACA-SO ₃ H), 4- phenoxy phenol degradation of active carbon airgel with a palladium catalyst (Pd / ACA), and supported on activated carbon airgel is an acid catalyst comprising a palladium _{(Pd / ACA-SO 3 H} ) is supported on the Performance Comparison Graph

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

The noble metal catalyst supported on the sulfonic acid-containing activated carbon aerogels impregnated with the cation-substituted heteropoly acid of the present invention is a catalyst for selectively decomposing carbon-oxygen-carbon bonds in the internal bond of lignin to produce an aromatic, _{x H 3.0-x PW 12 O} 40 / ACA-SO 3 H (M is at least one noble metal selected from the group consisting of palladium, rhodium, ruthenium and _{platinum, Q x H 3.0-x PW} 12 O 40 is a cation exchange , Q is an alkali metal or ammonium ion, ACA is an activated carbon aerogel, and -SO ₃ H is a sulfonic acid group). After reacting a high concentration of sulfuric acid with activated carbon aerogels, sulfonic acid is added to the surface of activated carbon aerogels To 5% by weight based on the weight of the activated carbon aerogels, in the range of 5 to 70% by weight, based on the weight of the activated carbon aerogels, of sulfonic acid-containing heteropolyacid And a carrier of palladium, rhodium, characterized in that one prepared by supporting a ruthenium and one or more kinds of noble metals selected from the group consisting of, by weight of the activated carbon airgel platinum 1-30% by weight.

In the catalyst of the present invention, a noble metal supported on activated carbon aerogels containing acid sites is used as a catalyst, more specifically, one selected from noble metals such as palladium, platinum, rhodium and luciferum is used as the catalyst. The amount of the noble metal carried on the activated carbon aerogels is in the range of 1 to 30% by weight based on the activated carbon aerogels. The active carbon aerogels used in the catalyst are selected from resorcinol and formaldehyde as reactants, activated carbon aerogels polymerized with sodium hydrogencarbonate, and used in the production of the activated carbon aerogels. The active carbon aerogels include potassium hydroxide, phosphoric acid, Zinc and the like are used as a carbon airgel activating material. In addition, the activated carbon aerogels were treated with sulfonic acid to impart acid characteristics to the activated carbon aerogels, and the cation-substituted heteropoly acids were impregnated with activated carbon aerogels containing sulfonic acids, and the cation-substituted heteropoly acids treated with the catalysts were activated with 5 to 50 wt% %. ≪ / RTI > Finally, the noble metal catalyst containing the sulfonic acid prepared in the present invention and impregnated with the cation-substituted heteropoly acid to carry the active carbon aerogels including the acid sites has the formula M / Q _x H _3.0-x PW ₁₂ O ₄₀ / ACA-SO ₃ H Wherein M is one selected from the group consisting of palladium, platinum, rhodium, ruthenium, etc. Q is a heteropolyacid-substituted cation selected from an alkali metal or ammonium ion and ACA is resorcinol and formaldehyde Activated carbon aerogels activated carbon autogas produced by polymerization, and SO ₃ H is sulfonic acid contained in activated carbon aerogels).

The noble metal catalyst supported on the activated carbon aerogels containing the acid sites for decomposition of the lignin model compound of the present invention is prepared by polymerizing (a) resorcinol (formaldehyde) and formaldehyde with sodium hydrogen carbonate To produce an RF (resorcinol-formaldehyde) gel; (b) exchanging the RF gel prepared in the step (a) with acetone and drying; (c) carbonizing the RF gel produced in the step (b) to produce carbon aerogels; (d) pre-treating the carbon aerogels produced in the step (c) with potassium hydroxide, phosphoric acid and zinc chloride to produce active carbon aerogels; (e) washing the activated carbon aerogels produced in the step (d) with water, followed by drying; (f) reacting the activated carbon aerogels produced in the step (e) with sulfuric acid to add a sulfuric acid to the sulfonic acid; (g) impregnating cation-substituted heteropolyacids to further add acid sites to the activated carbon aerogels containing sulfonic acid produced in step (f); (h) producing an activated carbon airgel having noble metal oxide supported on an activated carbon aerogels containing a sulfonic acid produced in the step (g) by impregnation with a cation-substituted heteropoly acid and carrying a noble metal on the activated carbon aerogels; (i) reducing the noble metal oxide supported on the activated carbon aerogels containing the acid sites produced in the step (h) with hydrogen to obtain a noble metal catalyst (M / Q _x H _3.0-x PW ₁₂ O ₄₀ / ACA-SO ₃ H).

The ratio (R / F ratio) of resorcinol to formaldehyde used in step (a) is between 0.1 and 2.0, and they are sufficiently dissolved in distilled water and mixed. Also, sodium bicarbonate is added as a catalyst to the mixed solution of resorcinol and formaldehyde to initiate the polymerization reaction, and the amount of sodium hydrogencarbonate added is preferably 1/50 to 500 in terms of resorcinol. In the polymerization using the catalyst, the polymerization reaction time is preferably from 1 to 3 hours, and after the initiation of polymerization, the polymerization reaction is maintained at 80 to 120 ° C for 12 to 24 hours to sufficiently form an RF gel.

In step (b), the water contained in the RF gel prepared in step (a) is exchanged with acetone. After the RF gel containing water is thoroughly washed with a high purity acetone solution at 50 ° C, Dry for 3 to 5 hours to produce RF gel.

In step (c), the RF gel produced in step (b) is carbonized to produce carbon aerogels. The carbon gelation conditions of the RF gel include a temperature range of 200 to 800 ° C., a nitrogen atmosphere, and a carbonization do.

In step (d), the step of activating the carbon airgel produced in step (c) may be a step of activating carbon aerogels selected from potassium hydroxide (KOH), phosphoric acid (H ₃ PO ₄ ) and zinc chloride (ZnCl ₂ ) Mix by impregnation method. The carbon aerogels mixed with the activating material are sufficiently activated at a temperature of 200 to 800 ° C for 1 to 3 hours in a nitrogen atmosphere. The ratio of the active material to the carbon aerogels is between 0.5 and 5, preferably between 1 and 2, by weight.

In step (e), the activated carbon aerogels containing the active material produced in step (d) are washed with water, and the acid material remaining on the activated carbon aerogels is thoroughly washed using distilled water. When the pH of the washing water is between 6.5 and 7.0, it is judged that the active substance is sufficiently washed. The washed activated carbon aerogels are dried at 110 ° C for 5 hours.

In step (f), the activated carbon aerogels and the sulfuric acid are reacted to include the acid sites in the activated carbon aerogels produced in step (e). The sulfuric acid and the activated carbon aerogels at a concentration of 10 M are reacted at a temperature of 50 to 150 ° C The reaction is carried out in a nitrogen atmosphere for ~ 24 hours and then washed with hot distilled water. At the completion of the washing, it is judged that the sulfuric acid is sufficiently removed when the pH of the washing water is between 6.5 and 7.0. The activated carbon aerogels containing the washed sulfonic acid are dried at 110 ° C for 5 hours.

In step (g), the step of impregnating the cation-substituted heteropolyacid to further include the acid sites in the activated carbon aerogels containing the sulfonic acid produced in the step (f), wherein the heteropoly acid is introduced into the activated carbon aerogels containing sulfonic acid And dried at 80 ° C for 3 hours. Activated carbon aerogels, including dried heteropolyacids, are substituted for selected cations. The substituted cationic Q is one selected from an alkali metal or ammonium ion in an aqueous solution state, and the cationic material in an aqueous solution state is mechanically mixed with the active carbon aerogels carrying the heteropoly acid. Activated carbon aerogels containing cation-substituted heteropolyacids are dried at 110 ° C for 5 hours and then calcined at 250 to 300 ° C for 2 to 5 hours to be used as noble metal catalyst carriers. The weight ratio of the treated cationic heteropoly acid is between 1 and 70 wt.%, Preferably between 10 and 30 wt.%, Based on the activated carbon aerogels.

In step (h), the noble metal material is supported on the activated carbon aerogels impregnated with the cation-substituted heteropoly acid, which contains the sulfonic acid produced in step (g), and then the sintered material is used. Examples of the precious metal M usable include palladium, platinum, rhodium, And the noble metal precursor is completely dissolved in a solvent, and then impregnated with the activated carbon aerogels. Activated carbon aerogels mixed with precious metal precursors are thoroughly dried at 80 ° C for 5 hours and then calcined at a temperature ranging from 250 to 350 ° C for 2 to 5 hours in an air atmosphere. As a result, the noble metal oxide is supported on the activated carbon aerogels containing the acid sites. When the calcination temperature is 250 ° C or less, the calcination is incomplete, and when the temperature is 350 ° C or more, sintering of the noble metal particles may occur. The proportion of the noble metal supported is 1 to 30% by weight, preferably 3 to 7% by weight of the activated carbon aerogels.

In step (i), the noble metal oxide supported on the activated carbon aerogels including the acid sites generated in step (h) is reduced to hydrogen and converted into noble metal form. The reduction is carried out in a hydrogen atmosphere at 120 DEG C for 5 to 12 hours.

In addition, the present invention uses a lignin model compound to simplify the complicated internal structure of lignin in lignin decomposition, and a model representative of the most frequently occurring carbon-oxygen bond (CO bond) Were selected. 4-phenoxyphenol, which is representative of 4-carbon-oxygen-5-carbon (4-O-5) bond having the highest binding energy among the carbon-oxygen bonds of lignin, was selected as a model compound. The structural formula of cyphenol was presented.

In addition, the present invention uses the noble metal supported on active carbon aerogels prepared above as a catalyst to decompose the lignin model compound, and the reaction is a liquid phase reaction in which the catalyst is dispersed heterogeneously in the solvent. The solvent that can be used for the reaction was selected as a hydrocarbon material having a breaking point of 200 ° C or higher without decomposing into a noble metal catalyst supported on active carbon aerogels containing acid sites. Hexadecane (C ₁₆ H ₃₄ ) was selected in the present invention .

In the present invention, the amount of lignin before the reaction and the amount of lignin after the reaction were analyzed by gas chromatography to calculate the conversion rate of the lignin model compound. The amount of phenol, benzene and cyclohexanol produced as a result of 4-phenoxyphenol decomposition was analyzed by gas chromatography. The conversion of the lignin model compound and the selectivity and yield of the main products (phenol + benzene + cyclohexanol) Using the following equation.

Production Example 1

In the present invention, a noble metal catalyst supported on activated carbon aerogels containing sulfonic acid and impregnated with cation-substituted heteropoly acid and having a acid site is applied to the decomposition reaction of lignin model compound. A process for preparing a noble metal catalyst supported on activated carbon aerogels containing a acid site by introducing sulfonic acid to incorporate the acid sites in the activated carbon aerogels and further impregnating the cation-substituted heteropolyacids is shown in FIG. The activated carbon aerogels were prepared by carbonizing the RF gels produced by polymerizing resocinol and formaldehyde. The carbon aerogels prepared above were activated by using phosphoric acid (H ₃ PO ₄ ) Respectively. The ratio of resorcinol to formaldehyde used is 0.5 and the ratio of sodium hydrogencarbonate used as catalyst is 1/200 in terms of resorcinol base weight ratio. Resorcinol and formaldehyde are dissolved in distilled water, respectively, and mixed in a single container. The calculated amount of catalyst is added to the fully mixed resorcinol and formaldehyde solution to initiate the polymerization reaction. The polymerization initiated resorcinol / formaldehyde mixed solution is placed in a sealed container and reacted at 100 ° C for 10 hours to produce a solid RF gel. The solid RF gel is washed with acetone and dried at 80 ° C for 5 hours. The dried RF gel is carbonized at 500 ° C for 1 hour under a nitrogen atmosphere to produce carbon aerogels (CA). The carbon aerogels produced above are mixed by impregnation with phosphoric acid and sufficiently dried at 100 ° C. The ratio of phosphoric acid used as the active material is 1 fold in weight ratio based on carbon aerogels. Carbon aerogels impregnated with phosphoric acid are carbonized and activated at 800 ° C. for 1 hour in a nitrogen atmosphere to produce an activated carbon aerogel (ACA). The activated carbon aerogels are washed with distilled water and rinsed until the pH of the wash water is between 6.5 and 7. The washed activated carbon aerogels are dried at 110 ° C for 3 hours.

To add acid sites to activated carbon aerogels (ACA), activated carbon aerogels were reacted with 10 molar sulfuric acid to introduce sulfonic acid functional groups into activated carbon aerogels. In a high-temperature and high-pressure reactor, 1 g of activated carbon aerogels are added to 100 ml of sulfuric acid at a concentration of 10 moles, and then nitrogen atmosphere is created in the reactor. After reacting the temperature of the high-temperature high-pressure reactor containing sulfuric acid and activated carbon aerogels at 100-180 ° C. for 10-18 hours, the physically adsorbed sulfuric acid is removed from the activated carbon aerogels using distilled water at 50 ° C. Activated carbon aerogels containing acid sites from which physically adsorbed sulfuric acid has been removed are dried at 110 ° C for 3 hours.

The heteropoly acid used to impregnate the activated carbon aerogels containing sulfonic acid with cation-substituted heteropolyacids is 12-tungstophosphoric acid (H ₃ PW ₁₂ O ₄₀ ), and the substituted cations use a cesium precursor. The activated carbon aerogels are treated with aqueous solution of heteropoly acid by impregnation method and dried at 80 ° C for 3 hours. The dried activated carbon aerogels were cationically substituted with a predetermined amount of aqueous cesium precursor and calcined at 250 ° C for 5 hours to obtain activated carbon aerogels containing sulfonic acid and cation-substituted heteropoly acid (YCs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H, Y = 10, 15, 20, 25, and 30 wt%). The amount of treated cationic heteropoly acid represented by Y is 10 to 30 wt% based on activated carbon aerogels and the amount of substituted cations cesium is set to 2.5 molar ratio. In order to support palladium, a palladium precursor (palladium nitrate, Pd (NO ₃ ) ₂ ) is dissolved in distilled water and impregnated in activated carbon aerogels. The amount of palladium supported on the activated carbon aerogels containing the acid sites is 5 wt%, and the mixture is calcined at 250 DEG C for 2 hours to produce palladium oxide-supported active carbon aerogels containing acid sites. (Pd / YCs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H, Y = 10) in a hydrogen atmosphere at 120 ° C. to reduce the palladium oxide supported on the activated carbon aerogels containing the fired acid sites , 15, 20, 25, and 30% by weight) as a lignin model compound decomposition catalyst.

Comparative Preparation Example 1

The cation-substituted heteropolyacid produced in Preparation Example 1 was treated to measure the activity of a palladium catalyst (Pd / 15Cs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H) supported on activated carbon aerogels containing acid sites A palladium catalyst (Pd / ACA, ACA activated carbon aerogel) supported on carbon aerogels was prepared.

The ratio of resorcinol to formaldehyde used in the preparation of the carbon aerogels is 0.5, and the ratio of sodium hydrogencarbonate used as the catalyst is 1/200 as a resorcinol-based weight ratio. Resorcinol and formaldehyde are dissolved in distilled water, respectively, and mixed in a single container. The calculated amount of catalyst is added to the fully mixed resorcinol and formaldehyde solution to initiate the polymerization reaction. The polymerization initiated resorcinol / formaldehyde mixed solution is placed in a sealed container and reacted at 100 ° C for 10 hours to produce a solid RF gel. The solid RF gel produced above is washed with acetone and then dried at 80 ° C. The dried RF gel is carbonized at 800 ° C under a nitrogen atmosphere for 1 hour to produce carbon aerogels. Phosphoric acid is mixed with the carbon aerogels produced above by the impregnation method, and sufficiently dried at 100 ° C. The ratio of phosphoric acid used as the active material is 1 fold in weight ratio based on carbon aerogels. Carbon aerogels impregnated with phosphoric acid are carbonized and activated at 800 DEG C for 1 hour in a nitrogen atmosphere. The activated carbon aerogels are washed with distilled water and rinsed until the pH of the wash water is between 6.5 and 7. The washed activated carbon aerogels are dried at 110 ° C for 3 hours. The activated carbon aerogels produced above were prepared by impregnation with palladium supported on activated carbon aerogels at 5 wt% on the basis of activated carbon aerogels, and calcined at 250 ° C for 3 hours to obtain palladium oxide-impregnated activated carbon aerogels . In order to reduce the noble metal oxide supported on the activated carbon aerogels to noble metal, the noble metal oxide supported on the carbon aerogels is reduced at 120 ℃ for 4 hours in the hydrogen atmosphere and used as catalyst (Pd / ACA, ACA is activated carbon aerogel).

Comparative Production Example 2

Comparing the decomposition performance of the lignin model compound with the palladium catalyst (Pd / Cs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H) supported on activated carbon aerogels containing acid sites by treatment with the cation-substituted heteropolyacid produced in Preparation Example 1 (Pd / ACA-SO ₃ H) supported on active carbon aerogels containing sulfonic acid alone.

The active carbon aerogels are reacted by dispersing the active carbon aerogels in a high-concentration sulfuric acid solution to include the acid sites. In a high-temperature and high-pressure reactor, 1 g of activated carbon aerogels are added to 100 ml of sulfuric acid at a concentration of 10 moles, and then nitrogen atmosphere is created in the reactor. After reacting the temperature of the high-temperature high-pressure reactor containing sulfuric acid and activated carbon aerogels at 100-180 ° C. for 10-18 hours, the physically adsorbed sulfuric acid is removed from the activated carbon aerogels using distilled water at 50 ° C. Activated carbon aerogels containing acid sites from which physically adsorbed sulfuric acid has been removed are dried at 110 ° C for 3 hours. Palladium precursor (palladium nitrate, Pd (NO ₃ ) ₂ ) is dissolved in distilled water to support palladium on activated carbon aerogels containing acid sites, and then impregnated on active carbon aerogels. The amount of palladium supported on the active carbon aerogels containing the acid sites is 5 wt%, and the mixture is calcined at 250 DEG C for 3 hours to produce activated carbon aerogels carrying palladium oxide. In order to reduce the palladium oxide supported on activated carbon aerogels containing fired acid sites, it is reduced at 120 ° C under a hydrogen atmosphere for 4 hours and used as a catalyst. The palladium catalyst supported on phosphoric acid-activated activated carbon aerogels prepared by the above method is expressed as (Pd / ACA-SO ₃ H).

Example 1

The catalyst was applied to the lignin model compound decomposition reaction using a palladium catalyst supported on active carbon aerogels containing sulfonic acid produced in Production Example 1 and impregnated with cesium ion substituted heteropoly acid and containing acid sites. The lignin degradation reaction occupied the highest frequency of lignin interactions and used 4 - phenoxyphenol which is representative of carbon - oxygen bond. To decompose 4-phenoxyphenol, a high-temperature high-pressure vessel reactor was used, and hexadecane was used as a solvent. The reaction temperature was maintained at 200 ° C. under a hydrogen atmosphere of 10 atm for 1 hour. The reaction mixture containing 4-phenoxyphenol and sulfonic acid introduced into the reaction was impregnated with cation-substituted heteropolyacid and palladium catalyst supported on activated carbon aerogels containing acid sites (Pd / YCs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H, Y = 10, 15, 20, 25, and 30 wt%).

Comparative Example 1

In order to verify the performance of the palladium catalyst (Pd / 15Cs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA) supported on activated carbon aerogels impregnated with cesium ion substituted heteropoly acid containing sulfonic acid applied in Example 1, (Pd / ACA) supported on activated carbon aerogels. The lignin degradation reaction occupied the highest frequency of lignin interactions and used 4 - phenoxyphenol which is representative of carbon - oxygen bond. To decompose 4-phenoxyphenol, a high-temperature high-pressure vessel reactor was used, and hexadecane was used as a solvent. The reaction temperature was maintained at 200 ° C under a hydrogen atmosphere of 10 atmospheres for 1 hour. The weight ratio of 4-phenoxyphenol and palladium catalyst (Pd / ACA) supported on carbon aerogels was 20.

Comparative Example 2

To verify the performance of a palladium catalyst (Pd / 15Cs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H) supported on activated carbon aerogels impregnated with cesium ion substituted heteropoly acid containing sulfonic acid applied in Example 1, The precious metal catalyst (Pd / ACA-SO ₃ H) supported on activated carbon aerogels containing the sulfonic acid alone produced in Example 2 was applied to the lignin decomposition reaction. The lignin degradation reaction occupied the highest frequency of lignin interactions and used 4 - phenoxyphenol which is representative of carbon - oxygen bond. A high-temperature high-pressure vessel reactor was used to decompose 4-phenoxyphenol, and hexadecane was used as a solvent. The reaction temperature was maintained at 200 ° C. under a hydrogen atmosphere of 10 atmospheres for 1 hour. The reaction temperature of the palladium catalyst (Pd / ACA-SO ₃ H) supported on activated carbon aerogels containing reactant 4-phenoxyphenol and sulfonic acid The weight ratio is 20.

Pd / YCs containing sulfonic acid and impregnated with cesium ion substituted heteropoly acid and supported on activated carbon aerogels containing acid sites _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H, Y = 10, 15, 20, 25 and 30% by weight)

(Pd / YCs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H, Y = 10, 15, 20, 25, and 25) supported on active carbon aerogels containing sulfonic acid and impregnated with cation-substituted heteropoly acid 30% by weight) is shown in Table 1. The amount of cation-substituted heteropoly acid contained in the sulfonic acid-containing activated carbon aerogels decreased from 1075 m ² / g to 948 m ² / g as the amount of the cation-substituted heteropoly acid increased from 10 wt% to 30 wt%. The decrease in the specific surface area of the active carbon aerogels containing sulfonic acid as the cation-substituted heteropoly acid is increased increases the amount of the cation-substituted heteropoly acid having a relatively small specific surface area. Figure 4 shows the catalyst _{Pd / YCs 2 .5 H 0 .5} PW nitrogen adsorption-desorption curve of the _{12 O 40 / ACA-SO 3} H (Y = 10-30% by weight) catalyst. _{Pd / YCs 2 .5 H 0 .5} PW 12 O 40 / ACA-SO 3 H (Y = 10-30% by weight) Catalyst nitrogen adsorption and desorption curve was observed all the pores in the form of type 4.

FIG. 5 shows an XRD pattern in which the crystal structure of Pd / YCs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H (Y = 10-30 weight%) catalyst was analyzed. 10 to 30% by weight of the cation exchange heteropolyacid catalyst of the Pd / 10Cs _2.5 containing _0.5 H when the _{PW 12 O 40 / ACA-SO} 3 H and _{Pd / 15Cs 2.5 H 0.5 PW 12} O 40 / ACA-SO 3 H catalyst The heteropoly acid-related peak is not observed because the degree of dispersion of the cation-substituted heteropoly acid catalyst is high. On the other hand, in the case of a catalyst containing 20 wt% or more of cation-substituted heteropoly acid, the crystal structure of the heteropoly acid is confirmed by the XRD pattern. As the amount of the cation-substituted heteropoly acid catalyst is increased, the intensity of the related XRD peak is observed.

Table 2 shows the results of CHNS analysis of the sulfur content of the prepared catalyst Pd / YCs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H (Y = 10, 15, 20, 25 and 30 wt%) . The sulfur content is distributed between 0.87 and 0.92 wt% based on the carbon content of the catalyst, and is not correlated with the amount of the cationic heteropolyacid catalyst impregnated. Table 3 shows the contents of palladium and cation-substituted heteropolyacids in the prepared catalyst Pd / YCs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H (Y = 10, 15, 20, 25 and 30 wt%) The results of ICP-AES analysis are shown. As a result of ICP-AES analysis, the content of cation-substituted heteropoly acid was 2 to 4% by weight less than the theoretical value added in the experiment. This is because the cation-substituted heteropoly acid physically impregnated on the surface of the activated carbon aerogels was removed during the cleaning process. However, it can be confirmed that the cation-substituted heteropoly acid impregnated in the pores remains unremoved even in the washing step. The amount of palladium supported is 4.8-5.0 wt%, which is not much different from the theoretical value of 5 wt%. This result confirms that the impregnated palladium was successfully supported on the activated carbon aerogel pores. In addition, the successful deposition of palladium can be confirmed by the palladium peak which can be confirmed in FIG.

catalyst Specific surface area (m ² / g) Pd / 10Cs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H 1075 Pd / 15Cs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H 1002 Pd / 200Cs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H 988 Pd / 25Cs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H 965 Pd / 30Cs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H 948

catalyst  S content (wt%) Pd / 10Cs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H 0.88 Pd / 15Cs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H 0.91 Pd / 200Cs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H 0.87 Pd / 25Cs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H 0.92 Pd / 30Cs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H 0.89

catalyst Cs _{2 .5H 0 .5} PW ₁₂ O ₄₀ Content (wt%) Pd content (% by weight) theory real theory real Pd / 10Cs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H 10 8.2 5 4.9 _{Pd / 15Cs 2 .5 H 0 .5} PW 12 O 40 / ACA-SO 3 H 15 13.8 5 4.8 _{Pd / 20Cs 2 .5 H 0 .5} PW 12 O 40 / ACA-SO 3 H 20 17.4 5 4.9 Pd / 25Cs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H 25 22.3 5 5.0 Pd / 30Cs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H 30 26.8 5 4.8

A palladium catalyst (Pd / YCs) impregnated with cesium ion substituted heteropoly acid containing sulfonic acid and supported on activated carbon aerogels containing acid sites _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H, Y = 10, 15, 20, 25, and 30 wt%) of 4-phenoxyphenol decomposition

The reaction was carried out in the same manner as in Example 1 to evaluate the performance of the palladium catalyst supported on activated carbon aerogels containing sulfonic acid and cation-substituted heteropolyacid to decompose 4-phenoxy phenol, which is a lignin model compound. The products produced in the 4-phenoxyphenol decomposition reaction were benzene, cyclohexanol, and phenol, respectively, identified by GC-MS. The conversion, selectivity, and yield are calculated according to equations (1), (2), and (3) to evaluate the catalytic activity after catalytic cracking of 4-phenoxyphenol. As shown in Example 1, the lignin model compound 4-phenoxyphenol was decomposed using a palladium catalyst containing a sulfonic acid and impregnated with a cation-substituted heteropoly acid and supported on an activated carbon aerogel including an acid site. As shown in FIG. 6, the 4-phenoxyphenol conversion and the main product yield show a volcanic graph according to the amount of cation-substituted heteropoly acid impregnated in the catalyst. When cation exchange heteropoly acid in the catalyst is set forth in the 15 _{wt.% (Pd / 15Cs 2.5 H 0.5} PW 12 O 40 / ACA-SO 3 H) one week conversion and product yields shows the maximum values, respectively 94.8% and 67.5%. Also, when the amount of cation-substituted heteropoly acid is between 10 wt% and 30 wt%, the conversion is about 87-95%, and the main product yield is observed between about 45-70%. FIG. 7 shows the yield of the main product among the results of 4-phenoxyphenol decomposition with the Pd / YCs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H catalyst conducted in Example 1. The main products resulting from the 4-phenoxyphenol decomposition are cyclohexanol, benzene, and phenol. The yield of phenol was constantly observed from 1.3 to 2.2 wt% irrespective of the content of cation-substituted heteropoly acid, and the main product yield of cyclohexanol (31.2%) and benzene (35%) was 15 wt% The highest yield is observed.

A palladium catalyst (Pd / 15Cs) containing sulfonic acid and impregnated with cesium ion substituted heteropoly acid and supported on activated carbon aerogels containing acid sites _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H), palladium catalyst (Pd / ACA) supported on activated carbon aerogels, palladium catalyst supported on activated carbon aerogels containing sulfonic acid (Pd / ACA-SO ₃ H) in 4-phenoxyphenol decomposition

8 shows Example 1, Comparative Example 1, containing the sulfonic acid cation exchange conducted by the two acid sites heteropoly acid is impregnated the active carbon airgel with a palladium catalyst supported on a (Pd / 15Cs _2.5 containing H _0.5 PW ₁₂ O ₄₀ / ACA- SO ₃ H), a palladium catalyst (Pd / ACA) supported on activated carbon aerogels, and a palladium catalyst (Pd / ACA-SO ₃ H) supported on activated carbon aerogels containing sulfonic acid. The lignin model compound 4-phenoxyphenol The results are shown in Fig. When 4-phenoxyphenol was decomposed with a palladium catalyst supported on activated carbon aerogels, the conversion was found to be 62.4% and the main product yield was found to be 49.9%. When 4 - phenoxyphenol was decomposed using a palladium catalyst supported on activated carbon aerogels containing sulfonic acid, the conversion was 71.9% and the main product yield was 61.0%. Pd / ACA-SO ₃ H> Pd / ACA (Pd / 15Cs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H> Pd / ACA-SO ₃ H) was obtained when the 4-phenoxyphenol was decomposed using the above three catalysts. (Pd / 15Cs _2.5 H _0.5 PW ₁₂ O ₄₀ / ACA-SO ₃ H) supported on activated carbon aerogels containing a sulfonic acid and cation-substituted heteropoly acid in the catalyst, Exhibits excellent 4-phenoxyphenol decomposition performance.

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. Accordingly, such improvements and modifications will fall within the scope of the present invention as long as they are obvious to those skilled in the art.

Claims (3)

In a catalyst for selectively decomposing a carbon-oxygen-carbon bond in an internal bond of lignin to produce an aromatic group,
The catalyst has the formula _{M / Q x H 3.0-x} PW 12 O 40 / ACA-SO 3 H (M is at least one noble metal selected from the group consisting of palladium, rhodium, ruthenium and platinum, Q _x H _3.0-x PW ₁₂ O ₄₀ is a cation-substituted heteropoly acid, Q is an alkali metal or ammonium ion, ACA is an active carbon airgel, and -SO ₃ H is a sulfonic acid group)
Reacting a high concentration of sulfuric acid with activated carbon aerogels, and then binding sulfonic acid to the surface of the activated carbon aerogels at a ratio of 0.5 to 5% by weight to the sulfonic acid-containing carbon aerogels. The cation-substituted heteropolyacids are added to the activated carbon aerogels in an amount of 5 to 70 wt% % By weight, based on the weight of the activated carbon aerogels, of at least one noble metal selected from the group consisting of palladium, rhodium, ruthenium and platinum. A precious metal catalyst supported on activated carbon aerogels containing sulfonic acid impregnated with heteropoly acid. The method according to claim 1,
The activated carbon aerogels are obtained by activating carbon aerogels produced by polymerization of resocinol and formaldehyde with at least one activating substance selected from the group consisting of potassium hydroxide, phosphoric acid, and zinc chloride,
Wherein the ratio of the resorcinol to the formaldehyde (R / F ratio) is in the range of 0.1 to 2.0 in terms of molar ratio, and the noble metal catalyst supported on the sulfonic acid-containing activated carbon aerogels impregnated with the cation-substituted heteropoly acid. A method for decomposing a lignin model compound, which decomposes lignin under a pressure of less than 50 atm and a temperature of less than 300 DEG C in the presence of the catalyst of claim 1 or 2 to produce an aromatic.

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