CN105330523A - Method for preparing cyclopentanone by taking biomass resource as raw material - Google Patents

Abstract

The invention belongs to the technical field of biomass conversion and utilization, and specifically relates to a method for preparing cyclopentanone by using biomass resources as raw materials. The present invention uses furfural derived from biomass as a raw material, in the presence of a metal-loaded catalyst, and uses hydrogen-containing gas as a reducing agent, undergoes hydrogenation rearrangement reaction in a high-pressure reactor or a fixed-bed reactor, and obtains cyclopentanone in one step ; The metal-loaded catalyst, its carrier is selected from Nb ₂ O ₅ , H-ZSM-5 molecular sieve, HY molecular sieve, Fe ₂ O ₃ , ZrO ₂ , Al ₂ O ₃ , SiO ₂ , CeO ₂ , MgO, activated carbon, And various crystal forms of TiO ₂ ; the active component is selected from one of Au, Pt, Ru, Rh, Pd, Ir, Ni, Cu; the loading of the active component is 0.1-5% of the total amount of the catalyst. The invention has mild reaction process conditions, cheap and easy-to-obtain raw materials, can realize the quantitative conversion of furfural to cyclopentanone, and belongs to an environment-friendly green chemical process.

Description

The method for preparing cyclopentanone with biomass resource as raw material

technical field

The invention belongs to the technical field of biomass conversion and utilization, and in particular relates to a method for preparing cyclopentanone.

Background technique

Due to the depletion of traditional energy sources and the increase in energy demand worldwide, the development of alternative energy sources is currently receiving great attention. Obtaining energy chemicals from renewable biomass resources and reducing the dependence of chemicals on petroleum and other petrochemical resources has important scientific significance and application prospects. Carbohydrates are the main components of biomass resources, and the bio-based platform compound furfural (FFA) can be efficiently obtained through hydrolysis and dehydration. In recent years, the catalytic conversion of FFA has aroused widespread interest of researchers at home and abroad, and great progress has been made. Using furfural as raw material, a variety of important chemical products can be produced through hydrogenation, oxidation, nitration, halogenation, condensation and other reactions. For example, the hydrogenation reaction of furfural can generate furfuryl alcohol, tetrahydrofurfuryl alcohol, 2-methylfuran, 2-methyltetrahydrofuran, etc.; the oxidation reaction of furfural can obtain furoic acid and maleic anhydride; the nitration reaction of furfural can produce 5 -Nitrofurfural diethyl ester; furfural can generate furan and tetrahydrofuran through decarbonylation reaction; and furfural resin can be prepared by furfural polycondensation. Therefore, the deep-processing series products using furfural as raw materials play an important role in the pharmaceutical industry, organic synthesis, and polymer material chemical industry. However, there are still some problems to be solved in the field of furfural conversion and utilization. One is to prepare a heterogeneous catalyst with a longer life to efficiently and quantitatively obtain a certain product, and the other is to develop a series of new methods for preparing downstream products from furfural. route.

Cyclopentanone is an important organic chemical raw material, mainly used in medicine, spices and rubber synthesis and other industries. For example, it can be used to synthesize spices such as methyl dihydrojasmonate, brandyne, and 2-n-hexylcyclopentanone; as an excellent solvent, cyclopentanone is also widely used in the electronics industry. There are two main methods for the preparation of cyclopentanone, namely decarboxylation and cyclization of adipic acid and oxidation of cyclopentene (Figure 1). The adipic acid decarboxylation and cyclization method is the main production technology currently used in industry (such as Chinese patent CN1594259, European patent EP306873). However, the raw material for preparing cyclopentanone by this route depends on the production of oxalic acid, which involves many steps. Moreover, the decarboxylation process is involved in the production process, the theoretical mass yield is relatively low, and the atom economy is not high. Cyclopentene oxidation is another technical route for preparing cyclopentanone (such as patents JP04312549, WO2003078372, WO2006032532), generally using Wacker-type oxidation catalysts, or using N ₂ O as an oxidant to directly react with cyclopentene to generate cyclopentanone . However, there are generally a large amount of chloride ions in the Wacker process, which not only corrodes the reactor but also easily increases chlorinated products; while the oxidation method using N ₂ O as an oxidant is generally carried out at high temperature (280°C) and high pressure (30MPa), and the reaction conditions are harsh. Therefore, it is of great significance to develop new raw materials and new routes for the preparation of cyclopentanone, especially to utilize cheap and abundant biomass resources.

Furfural (FFA) is a biomass-derived material that can substitute for petroleum-based compounds whose production and use have been established, and research on this furfural has been conducted so far. Furfural is industrially produced on a large scale using cheap agricultural and forestry wastes (such as corncobs, bagasse, cottonseed hulls, etc.) as raw materials. China is a major producer and exporter of furfural. In 2010, China's furfural output reached more than 300,000 tons, accounting for more than 80% of the world's total production. Both furfural and cyclopentanone have five carbon atoms, therefore, the direct conversion of furfural to cyclopentanone has important application value. Therefore, the preparation of cyclopentanone by hydrogenation and rearrangement of furfural has gradually become a hot spot in biomass research in recent years (Figure 2). For example, Chinese patent CN103159606A reported that at 100-180 ° C using Ru-Ce-SiO ₂ as a catalyst, the yield of furfural hydrogenation and rearrangement to obtain cyclopentanone was 72%; Conversion to prepare cyclopentanone; Chinese patent CN104069886A reports a Y-type molecular sieve supported catalyst, and the yield of furfural aqueous solution into cyclopentanone is 96%. Notably, each of the above documents dealing with furfural to cyclopentanone recognizes the need to improve the efficiency, selectivity and commercial competitiveness of this process. Indeed, the evolutionary development of the chemical industry towards the use of renewable feedstocks has intensified the need for improved or alternative commercial methods of producing cyclopentanone.

Contents of the invention

The purpose of the present invention is to provide a method for preparing cyclopentanone which is green and environment-friendly and has high product yield by using biomass resources as raw materials.

The method for preparing cyclopentanone provided by the present invention uses furfural derived from biomass as a raw material, in the presence of a metal-loaded catalyst, with hydrogen-containing gas (hydrogen or synthesis gas) as a reducing agent, in an autoclave or a fixed bed After hydrogenation and rearrangement reaction in the reactor, cyclopentanone can be obtained in one step.

The method of the invention does not depend on fossil resources at all, has fewer steps, is green and economical, and the conversion rate of furfural and the selectivity of cyclopentanone are close to 100%. So far, although there are some reports about the conversion of furfural to cyclopentanone, the yield of the product is very low. Therefore, the raw material route of the present invention is a technical route with original innovation.

In the method for preparing cyclopentanone provided by the present invention, steps such as catalytic hydrogenation and isomerization must be considered in the conversion of furfural to cyclopentanone. Therefore, it is necessary to design catalytic systems with different functions, such as catalyst supports and active components. The catalyst designed in the present invention is a metal-supported catalyst; the carrier used in the catalyst is selected from Nb ₂ O ₅ , H-ZSM-5 molecular sieve, HY molecular sieve, Fe ₂ O ₃ , ZrO ₂ , Al ₂ O ₃ , SiO ₂ , CeO ₂ , MgO, activated carbon, and various crystal forms of TiO ₂ ; the active component of the catalyst is selected from one of Au, Pt, Ru, Rh, Pd, Ir, Ni, Cu; the loading amount of the active component is the total amount of the catalyst 0.1-5% of the volume.

The preparation method of above-mentioned metal supported catalyst provided by the present invention, concrete steps are:

(1) Add 0.11.0 mmol L ^-1 precipitant to 100400 mL of HAuCl ₄ solution with a concentration of 0.252.5 mmol L ^-1 at 6080°C, and adjust the pH of the solution to 8.09.0;

(2) Add the oxide carrier to the solution obtained in step (1), stir for 26 hours, and cool to room temperature;

(3) Suction filter the solution obtained in step (2), and wash until there is no chloride ion in the solution, and then vacuum-dry the precipitate at 2030°C (preferably 25°C) for 1224h;

(4) The dried solid matter in step (3) was reduced in 5 vol% H ₂ /Ar at 200-400° C. for 16 hours to obtain the nano-gold catalyst of the present invention.

Wherein, the precipitating agent in step (1) is selected from one of NaOH, KOH, Na ₂ CO ₃ , and urea.

The invention provides that catalysts supported by metal active centers other than Au are all prepared by impregnation method. The preparation steps are:

The carrier is added to the aqueous solution of the metal salt, stirred for 4-8 hours, then evaporated to dryness with stirring at 60-100°C, and reduced in a hydrogen atmosphere at 200-600°C for 1-5 hours before use.

In the method for preparing cyclopentanone provided by the invention, the reaction takes water as the reaction medium, the concentration of the furfural aqueous solution is 1-30%, the reaction pressure is 0.5-8MPa, and the reaction temperature is 80-180°C. The preferred concentration is 5-10%, and the preferred pressure is 140-160°C.

In the method for preparing cyclopentanone provided by the present invention, the specific operation of carrying out the reaction in the high-pressure reactor is: add a certain amount of catalyst in a certain concentration of furfural aqueous solution, and rise to the designated reaction temperature after gas replacement; then, fill the Hydrogen or syngas to the specified reaction pressure, stirring for 0.1-12 hours to obtain cyclopentanone and other conversion products.

In the method for preparing cyclopentanone provided by the present invention, the specific operation of carrying out the reaction in the fixed-bed reactor is as follows: the catalyst is packed into the constant temperature section in the fixed-bed reactor, and a certain concentration of furfural solution is mixed with hydrogen or synthesized The gas enters a fixed-bed reactor equipped with a catalyst for reaction to obtain a mixture flow of cyclopentanone, water and hydrogen, which is separated to obtain pure cyclopentanone.

In the method for preparing cyclopentanone provided by the present invention, an appropriate co-solvent can also be added to the liquid phase reaction system.

The co-solvent is preferably one or more of common organic solvents, including: ethanol, methanol, acetone, butanol, and dioxane. More preferably the co-solvent is ethanol.

In the method for preparing cyclopentanone provided by the present invention, the hydrogen-containing gas is hydrogen or synthesis gas with any H ₂ /CO ratio.

The route provided by the invention has the following characteristics:

(1) Unlike the raw materials (such as adipic acid, cyclopentene, etc.) in the traditional method for preparing cyclopentanone, which are finally derived from fossil resources such as coal and petroleum, the raw material furfural used in the method provided by the invention is made from agricultural waste (corn core, cottonseed hulls, bagasse, etc.) are prepared by acid hydrolysis, and the production process has been industrialized. That is, the raw material furfural is renewable and does not depend on fossil resources. Therefore adopt furfural as the method for raw material preparation cyclopentanone, is a sustainable new route;

(2) In the method provided by the present invention, furfural is converted into cyclopentanone in an aqueous medium. Water is a cheap and abundant green solvent in nature, and the present invention uses water to replace organic solvents, which is not only beneficial to reduce production costs, but also beneficial to environmental protection;

(3) The raw material furfural and the product cyclopentanone are both carbon five compounds, and there is no loss of carbon during the reaction process, which has high atom economy. The conversion from furfural to cyclopentanone can be completed in one step in a reactor or in a fixed-bed reactor without separation of intermediate products, and the yield of cyclopentanone can reach 99%. Compared with the preparation method of adipic acid, the reaction steps from the final raw material to cyclopentanone are greatly reduced, which not only helps to reduce the cost, but also helps to increase the yield of cyclopentanone.

In a word, the whole production process is green and environmentally friendly, has high economic and social benefits, is a new way to prepare cyclopentanone, and has high industrialization prospects.

Description of drawings

Fig. 1 is the route for producing cyclopentanone from petrochemical resources.

Fig. 2 is the route for producing cyclopentanone from biomass resources.

FIG. 3 is a diagram of the reaction process of the Au/TiO ₂ catalytic system in Example 5.

detailed description

The present invention is further described below by way of examples.

Example 1, an iron oxide-supported gold catalyst was prepared by a co-precipitation method.

Put 0.468g HAuCl ₄ 4H ₂ O, 12.65g Fe(NO ₃ ) ₃ 9H ₂ O, 0.5L water into a 1L beaker, and drop in 0.2M sodium hydroxide solution with stirring at 80°C until the pH is about 8 , continue to stir for 30 minutes, filter the precipitate, wash with distilled water until there is no Cl ^- , dry in vacuum for 12 hours, and finally bake in a muffle furnace at 300°C for 4 hours. After cooling a catalyst was obtained, denoted as Au _{/ Fe2O3} .

Example 2, titanium oxide, aluminum oxide, magnesium oxide, cerium oxide, and niobium oxide supported gold catalysts were prepared by sodium hydroxide deposition-precipitation method.

Put 0.104gHAuCl ₄ 4H ₂ O and 0.5L water into a 1L beaker, drop in 0.2M sodium hydroxide solution with stirring at 80°C until the pH is about 7, and then add 5gTiO ₂ or Al ₂ O ₃ or CeO ₂ , continue stirring at 80°C for 2 hours, filter the precipitate, wash with distilled water until there is no Cl-, dry in vacuum for 12 hours, and finally bake in a muffle furnace at 300°C for 4 hours. After cooling a catalyst was produced, _denoted as Au/ _TiO2 , Au/ _Al2O3 , Au/MgO, Au/ _CeO2 or _Au / _Nb2O5 .

Example 3, zirconia, silicon oxide, H-ZSM-5 molecular sieve, and HY molecular sieve supported gold catalysts were prepared by ammonia deposition-precipitation method.

Put 0.104gHAuCl ₄ ·4H ₂ O, 0.5L water into a 1L beaker, put 5gZrO2 or _SiO2 into it, add ammonia solution with a concentration of _0.26M dropwise under stirring conditions until the pH is about 9, and continue to stir at room temperature for 8 hours. The precipitate was filtered, washed with distilled water until free of Cl ^- , dried in vacuum for 12 hours, and finally calcined in a muffle furnace at 300°C for 4 hours. After cooling a catalyst is obtained, denoted as Au/ZrO ₂ , Au/SiO ₂ , Au/H-ZSM-5 or Au/HY.

Example 4, preparation of supported metal catalysts other than Au.

Weigh 0.664gH ₂ PtCl ₆ 9H ₂ O, 0.420gPdCl ₂ , 0.508gRhCl ₃ , 0.646gRuCl ₃ 3H ₂ O, 0.670gH ₂ IrCl ₆ 6H ₂ O into five 100mL beakers, and then add 5gTiO ₂ and 20mL of water, stirred and carefully evaporated to dryness in a water bath at 80°C, and the obtained sample was baked in an oven at 100°C for 12 hours, transferred to a crucible and baked in a muffle furnace at 350°C for 2 hours, and then heated in 5% H ₂ /Ar After reduction at 300°C for 2 hours in air flow. Catalysts were obtained after cooling, denoted as Pt/TiO ₂ , Pd/TiO ₂ , Rh/TiO ₂ , Ru/TiO ₂ , Ir/TiO ₂ .

Embodiment 5, weigh catalyst 0.1g, 0.5g furfural in embodiment 1-4 respectively, drop into and fill in the 50mL stainless steel autoclave of 10mL water, then replace the air in the autoclave with hydrogen, charge into 4MPa hydrogen, the The temperature was raised to 160°C, and the reaction was carried out for 1 hour. The product is determined by the internal standard method of gas chromatography, and the internal standard is durene. The conversion rate of furfural and the selectivity of cyclopentanone are shown in Table 1. The reaction history of the Au/TiO ₂ catalytic system is shown in Figure 3.

Table 1

.

Embodiment 6, using the Au/TiO ₂ catalyst in embodiment 5. Catalyst preparation is the same as in Example 2, but the reaction temperature, reaction pressure and the concentration of reactant furfural are changed, and the results are shown in Table 2.

Table 2

.

Embodiment 7, catalyst Au/TiO in weighing embodiment ₁ Quality 0.1g, furfural 0.5g, drop in the 50mL stainless steel autoclave that fills 10mL water, then replace the air in the autoclave with hydrogen, charge into 4MPa synthesis gas ( H ₂ /CO=1, 2, 3, 4, 5), raise the temperature in the kettle to 160°C, and react for 1 hour. The product is determined by the internal standard method of gas chromatography, and the internal standard is durene. The conversion rate of furfural was 100%, and the selectivity of cyclopentanone was 99%.

Example 8, weighing 0.1g of the catalyst Au/ _TiO2 in Example 1, 0.5g of furfural, and 10mL of an aqueous solution containing a certain amount of ethanol (water/ethanol=1, 2, 3, 4, 5), and putting in 50mL of stainless steel In the autoclave, the air in the autoclave was replaced with hydrogen, filled with 4MPa hydrogen, and the temperature in the autoclave was raised to 160° C., and reacted for 1 hour. The product is determined by the internal standard method of gas chromatography, and the internal standard is durene.

Example 9, weighing 0.1g of the catalyst Au/ _TiO2 in Example 1, 0.5g of furfural, and 10mL of an aqueous solution containing a certain amount of acetone (water/acetone=1, 2, 3, 4, 5), and putting in 50mL of stainless steel In the autoclave, the air in the autoclave was replaced with hydrogen, filled with 4MPa hydrogen, and the temperature in the autoclave was raised to 160° C., and reacted for 1 hour. The product is determined by the internal standard method of gas chromatography, and the internal standard is durene.

In Example 10, 1 liter of water was added to a 10L autoclave, 192g (2 moles) of furfural was added to the autoclave, and 10g of 1% Au/TiO ₂ in Example 5 was added, the autoclave was sealed, and completely filled with hydrogen Replace the air in the reaction kettle, inflate and deflate it 3 times, then pass in hydrogen or synthesis gas to 4MPa again, heat to the reaction temperature of 160°C, and react for 10 hours. Fully react, cool down after the reaction is completed, filter the reaction solution, the filter cake is the catalyst, which can be recycled and used mechanically, pour 5L ethyl acetate into the filtrate, fully extract and separate, take the organic phase and rectify at normal pressure to obtain the ring pentanone. The results of gas chromatography-mass spectrometry analysis showed that the conversion rate of furfural was 100%, and the yield of cyclopentanone was 99%.

Embodiment 11, the reaction operation method of converting furfural into cyclopentanone in a fixed-bed reactor is as follows: 5% furfural aqueous solution is used as a raw material, and the catalyst packed in the fixed-bed reactor is 1g of 1%Au/TiO in Example 5 _2. The reaction temperature is 160°C, the reaction pressure is 4MPa, the molar ratio of hydrogen/furfural is 150/1, and the mass space velocity of furfural is 0.5h ^-1 . ,6,20,50,100h after the experimental results are shown in Table 3.

table 3

.

Example 12, mixing 0.5 g of acetylfuran and 10 mL of water to obtain a reaction stock solution. The reaction stock solution was added to a 50 mL autoclave, and 0.1 g of 1% Au/TiO ₂ in Example 5 was added. After replacing the air in the autoclave with hydrogen, the pressure in the autoclave was raised to 4 MPa, and the reactor was heated to 160° C. for 4 hours of reaction. The conversion rate of the reactant and the selectivity of the product are detected by gas chromatography, the conversion rate of acetylfuran is 98%, and the selectivity of 2-methylcyclopentanone is 97%.

Example 13, 0.5g of 5-methylfurfural and 10mL of water were mixed to obtain a reaction stock solution. The reaction stock solution was added to a 50 mL autoclave, and 0.1 g of 1% Au/TiO ₂ in Example 5 was added. After replacing the air in the autoclave with hydrogen, the pressure in the autoclave was raised to 4 MPa, and the reactor was heated to 160° C. for 4 hours of reaction. The conversion rate of the reactant and the selectivity of the product are detected by gas chromatography, the conversion rate of acetylfuran is 98%, and the selectivity of 3-methylcyclopentanone is 97%.

Example 14, mixing 0.5 g of propionyl furan and 10 mL of water to obtain a reaction stock solution. The reaction stock solution was added to a 50 mL autoclave, and 0.1 g of 1% Au/TiO ₂ in Example 5 was added. After replacing the air in the autoclave with hydrogen, the pressure in the autoclave was raised to 4 MPa, and the reactor was heated to 160° C. for 4 hours of reaction. The conversion rate of reactant and the selectivity of product are detected by gas chromatography, the conversion rate of acetylfuran is 98%, and the selectivity of 2-ethylcyclopentanone is 97%.

Example 15, 0.5g of 5-ethylfurfural and 10mL of water were mixed to obtain a reaction stock solution. The reaction stock solution was added to a 50 mL autoclave, and 0.1 g of 1% Au/TiO ₂ in Example 5 was added. After replacing the air in the autoclave with hydrogen, the pressure in the autoclave was raised to 4 MPa, and the reactor was heated to 160° C. for 4 hours of reaction. The conversion rate of reactant and the selectivity of product are detected by gas chromatography, the conversion rate of acetylfuran is 98%, and the selectivity of 3-ethylcyclopentanone is 97%.

Claims (8)

1. one kind is the method that cyclopentanone prepared by raw material with biomass resource, it is characterized in that, to be derived from the furfural of biomass as raw material, under metal load type catalyst exists, take hydrogen-containing gas as reductive agent, through hydrogenation-rearrangement reaction in autoclave or fixed-bed reactor, a step obtains cyclopentanone.

2. method according to claim 1, is characterized in that, described metal load type catalyst, and its carrier is selected from Nb ₂o ₅, H-ZSM-5 molecular sieve, HY molecular sieve, Fe ₂o ₃, ZrO ₂, Al ₂o ₃, SiO ₂, CeO ₂, MgO, gac, and the TiO of various crystal formation ₂; Active ingredient is selected from Au, Pt, Ru, Rh, Pd, Ir, Ni, Cu, in one; Activity component load quantity is the 0.1-5% of catalyzer total amount.

3. method according to claim 2, is characterized in that, described hydrogenation-rearrangement reaction is reaction medium with water, and furfural aqueous solution concentration is 1-30%, and reaction pressure is 0.5-8MPa, and temperature of reaction is 80-180 DEG C.

4. method according to claim 3, is characterized in that, the concrete operations carrying out reacting in autoclave are: in furfural aqueous solution, add a certain amount of catalyzer, rise to appointment temperature of reaction after gas displacement; Then, be filled with hydrogen or synthetic gas to specifying reaction pressure, stirring reaction 0.1-12 hour, namely obtains cyclopentanone and other converted products.

5. method according to claim 3, it is characterized in that, the concrete operations carrying out reacting in fixed-bed reactor are: by catalyst filling to the constant temperature zone in fixed-bed reactor, by furfural aqueous solution, the fixed-bed reactor that catalyzer is housed are entered with hydrogen or synthetic gas, reacting, obtain the mixture flow of cyclopentanone, water and hydrogen, obtaining pure cyclopentanone through being separated.

6. according to the method one of claim 1-5 Suo Shu, it is characterized in that, adding in described reaction system has solubility promoter.

7. method according to claim 6, is characterized in that, described solubility promoter is one or more in organic solvent ethanol, methyl alcohol, acetone, butanols, dioxane.

8. according to the method one of claim 1-5 Suo Shu, it is characterized in that, described hydrogen-containing gas is hydrogen or any H ₂the synthetic gas of/CO ratio.