阅读说明：本技术 一种铜基双金属催化剂高效催化3-环己烯甲醛转化制备甲苯的方法 (Method for preparing toluene by efficiently catalyzing conversion of 3-cyclohexene formaldehyde through copper-based bimetallic catalyst ) 是由 李昌志 肖钰雪 孟庆伟 张涛 于 2019-11-21 设计创作，主要内容包括：本发明提供一种铜基双金属催化剂高效催化3-环己烯甲醛转化制备甲苯的方法。3-环己烯甲醛在负载型铜基双金属催化剂作用下,于100℃-300℃发生脱氢芳化和加氢脱氧反应,高效生成甲苯。3-环己烯甲醛的催化反应在固定床反应器中进行,以正辛烷为溶剂,由高压流量泵将3-环己烯甲醛溶液打入反应管或氢气气体的吹扫下经过催化剂床层而获得甲苯。该过程反应工序简单,目标产物选择性高,底物可由来源于生物质资源的1,3-丁二烯和丙烯醛为原料一步反应得到,提供了直接由生物质制备芳香化学品的新方法。(The invention provides a method for preparing toluene by efficiently catalyzing conversion of 3-cyclohexene formaldehyde through a copper-based bimetallic catalyst. The 3-cyclohexene formaldehyde is subjected to dehydroaromatization and hydrodeoxygenation reactions at 100-300 ℃ under the action of a supported copper-based bimetallic catalyst to efficiently generate toluene. The catalytic reaction of the 3-cyclohexene formaldehyde is carried out in a fixed bed reactor, normal octane is taken as a solvent, and the 3-cyclohexene formaldehyde solution is pumped into a reaction tube by a high-pressure flow pump or passes through a catalyst bed layer under the blowing of hydrogen gas to obtain the toluene. The process has simple reaction process and high target product selectivity, and the substrate can be obtained by one-step reaction of 1, 3-butadiene and acrolein which are derived from biomass resources and are used as raw materials.)

1. A method for preparing toluene by catalyzing 3-cyclohexene formaldehyde conversion by a copper-based bimetallic catalyst is characterized in that a 3-cyclohexene formaldehyde solution is blown by carrier gas or injected into a gas-solid phase reactor filled with the copper-based bimetallic catalyst by a high-pressure flow pump and reacts at 100-300 ℃ to generate toluene.

2. The method of claim 1, wherein: the copper-based bimetallic catalyst is a supported catalyst and comprises an active component and a carrier; the active component is copper-palladium bimetal or copper-nickel bimetal; in the copper-based bimetallic catalyst, the loading amount of copper is 1-10 wt%, and the loading amount of palladium or nickel is 1 wt%.

3. A method according to claim 1 or 2, characterized in that: the carrier is one of activated carbon, alumina, silica, titanium dioxide and a silicon-aluminum molecular sieve.

4. A method according to claim 3, characterized by: the carrier is alumina, and the specific surface area of the carrier is more than 250m²G, pore volume > 0.35m³(g), bulk density 670-³。

5. The method of claim 1, wherein: the solvent of the 3-cyclohexene formaldehyde solution is n-octane, the concentration of the 3-cyclohexene formaldehyde solution is 50mg/mL-600mg/mL, and the flow rate of the 3-cyclohexene formaldehyde solution is 2.5 mL/h.

6. The method of claim 1, wherein: after the 3-cyclohexene formaldehyde solution is heated to 150 ℃, the solution is transferred into a gas-solid phase reactor by carrier gas; or the 3-cyclohexene formaldehyde solution is gasified in a gasification chamber provided with a carrier gas inlet and a 3-cyclohexene formaldehyde solution inlet and then introduced into a gas-solid phase reactor for reaction.

7. The method according to claim 6, characterized in that the carrier gas is one of hydrogen, nitrogen, helium, preferably hydrogen, and the flow rate of the carrier gas is 10mL/min to 200 mL/min.

8. The method of claim 1, wherein: the gas-solid phase reactor is a fixed bed reactor, and the 3-cyclohexene formaldehyde solution is injected by a high-pressure flow pump or enters the gas-solid phase reactor under the flow guidance of carrier gas to perform catalytic reaction to obtain the toluene.

9. The method of claim 1, wherein: the pressure of the reaction is 0.1MPa-0.2 MPa; the reaction temperature is 150-250 ℃.

10. The method of claim 1, wherein: and the reaction product toluene is led out from the gas-solid phase reactor and then collected by a cooler, and the temperature of the cooler is controlled below 0 ℃.

Technical Field

The invention belongs to the field of catalysis, and particularly relates to a method for preparing toluene with high selectivity by using 3-cyclohexene formaldehyde as a raw material under the action of a copper-based bimetallic catalyst.

Background

Aromatic hydrocarbon is a compound which contains benzene ring and only contains hydrocarbon, is an important organic chemical basic raw material, and is widely applied to the fields of resin, cellulose monomer, medicine, explosive, fuel, coating and fine chemicals. Toluene is an important chemical intermediate, and toluene oxide benzoic acid and sodium salt thereof can be used as bacteriostatic agents of latex, toothpaste, jam or other foods, can also be used as mordant for dyeing and printing, intermediates of pharmacy and dye, antirust agents of steel equipment, plasticizers, spices and the like. Toluene can also be converted to para-xylene by alkylation, disproportionation, and isomerization reactions. The production of petroleum grade toluene in China mainly comprises two production routes: extracted by a refinery, and the raw material is catalytic reformed gasoline; extracted by petrochemical plant, and the raw material is hydrocracking gasoline (PY GAS). Besides, the by-product coal tar from coking can also be used to produce benzene, toluene and xylene.

In recent years, with the development of economy, petroleum resources are more and more scarce, the energy demand is increasingly increased, and the problems of greenhouse effect, environmental pollution and the like are brought along. From the perspective of sustainable development, the development of a sustainable synthetic route using biomass resources is very significant. In addition, in the process of joint production of aromatic hydrocarbon, xylene is obtained through the steps of hydrogenation, reforming, aromatic hydrocarbon conversion, separation and the like under the conditions of a catalyst and high temperature and pressure, the process route is long, the energy consumption is high, and the development of a short and efficient conversion technology has important significance for industrial production.

Based on the background, in recent years, a plurality of energy petrochemical companies, research institutions and colleges all carry out a series of researches on the process for preparing aromatic hydrocarbon from biomass, and partial results are obtained. The American Sasa State university deeply studies the lignin catalytic cracking Aromatic hydrocarbon preparation process, and develops a Biomass to Aromatic process (Jim Lane. Anellotech, Umass ink license for branched methanol p-xylene technology. Biofuels Digest, 2012-11-29), the process takes plant straws, waste wood and the like as raw materials, Aromatic hydrocarbon is prepared by a catalytic fast pyrolysis technology, and process equipment (a reactor, a catalyst regenerator and the like) is similar to a petroleum refining (such as FCC) device, and has a certain application prospect. Biomass can also be subjected to chemical catalytic conversion to obtain various small molecules, which are subjected to Diels-Alder reaction, dehydrogenation or dehydration reaction to obtain aromatic chemicals (Settle A E., heterogeneneous Diels-Alder catalyst for biological-chemical aromatic compounds,2017, 19: 417-.

Professor Huber reported that propylene and furan were used as raw materials and reacted in a fixed bed reactor with a toluene yield of 35.2%, professor Paul J Danenhauer studied H-BEA molecular sieves, 2-methylfuran and ethylene in detail to synthesize toluene by a one-step reaction, and obtained toluene selectivity of approximately 46% (Green S.K., Patet R.E., Diels-Alder cyclic addition of 2-methylfuran and ethylene for recycled toluene. applied catalysis B: Environmental,2016,180; 487-496).

In addition, professor Lilandong university of south Kelvin reported AlCl₃The catalyst is cooperated with a NaY molecular sieve to convert 2-furan and ethylene to generate a Diels-Alder reaction to generate toluene, and the highest yield of the toluene reaches 70 percent under the optimal condition (Song S., Wu G., Diels-Alder and dehydration reaction of furan derivatives and ethylene catalyzed by liquid)acid and Lewis acid.Journal of Molecular catalysis A:Chemical,2016,420：134-141)。

Disclosure of Invention

The invention aims to provide a method for preparing p-toluene by simultaneously carrying out an arylation reaction and a hydrodeoxygenation reaction on 3-cyclohexene formaldehyde in a fixed bed reactor under the action of a supported copper-based catalyst.

In order to achieve the purpose, the invention adopts the technical scheme that:

the invention provides a method for preparing toluene by efficiently catalyzing conversion of 3-cyclohexene formaldehyde by a copper-based bimetallic catalyst, wherein a 3-cyclohexene formaldehyde solution is blown from a raw material bottle by carrier gas or injected into a gas-solid phase reactor filled with the copper-based bimetallic catalyst by a high-pressure flow pump, and catalytic dehydrogenation of a six-membered ring and hydrodeoxygenation reaction of aldehyde groups are simultaneously carried out within the temperature range of 100-300 ℃ to generate the toluene.

Based on the technical scheme, preferably, the copper-based bimetallic catalyst is a supported catalyst and comprises an active component and a carrier; the active component is copper-palladium bimetal or copper-nickel bimetal; in the copper-based bimetallic catalyst, the content of active component copper on the catalyst is 1 wt% -10 wt%, and the content of palladium or nickel on the catalyst is 1 wt%.

Based on the technical scheme, preferably, the carrier is one of activated carbon, alumina, silica, titanium dioxide and a silicon-aluminum molecular sieve.

Based on the technical scheme, preferably, the carrier is alumina, and the specific surface area of the carrier is more than 250m²G, pore volume > 0.35m³(g), bulk density 670-³。

Based on the technical scheme, preferably, the solvent of the 3-cyclohexene formaldehyde solution is n-octane, the concentration of the 3-cyclohexene formaldehyde solution is 50mg/mL-600mg/mL, and the flow rate of the 3-cyclohexene formaldehyde solution is 2.5 mL/h.

Based on the technical scheme, preferably, after the 3-cyclohexene formaldehyde solution is heated to 150 ℃, the raw material steam is transferred to the gas-solid phase reactor by carrier gas; or the 3-cyclohexene formaldehyde solution raw material can be gasified in a gasification chamber provided with a carrier gas inlet and a 3-cyclohexene formaldehyde solution raw material inlet and then introduced into a gas-solid phase reactor for reaction.

Based on the technical scheme, preferably, the carrier gas is one of hydrogen, nitrogen and helium, and hydrogen is preferred.

Based on the technical scheme, preferably, the gas-solid phase reactor is a fixed bed reactor, and the 3-cyclohexene formaldehyde solution reaction raw material is injected by a high-pressure flow pump or enters the gas-solid phase reactor under the flow guidance of a carrier gas to perform catalytic reaction to obtain the toluene.

Based on the above technical scheme, preferably, the reaction is carried out in a gas-solid phase reactor; the reaction pressure is not specially limited, and the pressure generated by the closed system is preferably 0.1MPa-0.2 MPa; the reaction temperature is 100-300 ℃.

Based on the technical scheme, preferably, the reaction product toluene is led out from the gas-solid phase reactor and then collected by a cooler, and the cooler is controlled below 0 ℃.

Specifically, 3-cyclohexene formaldehyde is subjected to dehydroaromatization and hydrodeoxygenation reactions at 100-300 ℃ under the action of a supported copper-based bimetallic catalyst to efficiently generate toluene. The catalytic reaction of the 3-cyclohexene formaldehyde is carried out in a fixed bed reactor, normal octane is taken as a solvent, and the 3-cyclohexene formaldehyde solution is pumped into a reaction tube by a high-pressure flow pump or passes through a catalyst bed layer under the blowing of hydrogen gas to obtain the toluene. The process has simple reaction process and high target product selectivity, and the substrate can be prepared from 1, 3-butadiene and acrolein which are derived from biomass resources through Diels-Alder reaction. The present invention provides a new method for the preparation of aroma chemicals directly from biomass.

Advantageous effects

(1) The reaction process of the invention has simple procedures and high selectivity of target products, and the 3-cyclohexene formaldehyde can be obtained by taking 1, 3-butadiene and acrolein which are derived from biomass resources as raw materials through a Diels-Alder one-step reaction, and can also be directly purchased from the Koyuan marketplace.

(2) The catalyst required by the invention is low in price and convenient to prepare, the catalyst is prepared by adopting a co-impregnation method, the loading capacity of palladium or nickel is less, the loading capacity of copper is gradually increased to achieve the modulation effect, the yield of toluene is increased along with the increase of the loading capacity of copper, and the optimal effect is achieved when the loading capacity of copper reaches 10%.

Detailed Description

Reference to copper-based bimetallic catalysts of the invention (catalysis of Pd-Cu Alloy on. gamma. -Al)₂O3-Supported Catalysts, Langmuir 2006,22, 9214-.

Comparative example 1

Preparation of the supported catalyst: all the supported catalysts are prepared by an isovolumetric impregnation method and are prepared by 1 percent Pd/Al₂O₃For example, the preparation process is as follows: weighing 1g palladium chloride containing Pd5.0145wt%Diluting the solution with water to 5g, grinding 4.95g of alumina (20-40 mesh, specific surface area > 280 m)²G, pore volume > 0.37m³(g), bulk density 710kg/m³) Soaking in the solution, stirring, standing for 12h, drying at 80 deg.C for 12h, oven drying at 120 deg.C overnight, calcining at 500 deg.C for 4h in air atmosphere, cooling to room temperature, and reducing with hydrogen at 300 deg.C (60 ml.min)^-1.g^-1) After the reduction is finished, the temperature is reduced to room temperature, O₂/N₂Mixed gas (O)₂Volume content 5%) for 4h to obtain 1 wt% Pd/Al₂O₃And collecting the catalyst for later use.

Comparative example 2

1wt％Ni/Al₂O₃The preparation process comprises the following steps: 0.25g of nickel nitrate hexahydrate is weighed and dissolved in 5g of water, after uniform stirring, 4.95g of the alumina is soaked in the solution, after uniform stirring, the solution is kept stand for 12h, dried at 80 ℃ for 12h, dried at 120 ℃ overnight, calcined at 500 ℃ for 4h in air atmosphere, cooled to room temperature and reduced by hydrogen at 500 ℃ (60ml^-1.g^-1) After the reduction is finished, the temperature is reduced to room temperature, O₂/N₂Mixed gas (O)₂Volume content 5%) for 4 h.

Example 1

Preparation of bimetallic supported catalyst: with 1% Pd 1% Cu/Al₂O₃For example, 4.95g of alumina were first impregnated with 5g of PdCl₂With Cu (NO)₃)₂Stirring the solution uniformly, standing for 12h, drying at 80 ℃ for 12h, drying at 120 ℃ overnight, calcining at 500 ℃ in air for 4h, reducing at 300 ℃ for 1h in hydrogen atmosphere, and controlling the hydrogen flow rate at 120 ml/min. Cooling to room temperature after reduction, and adopting O2/N₂Mixed gas (O)₂Volume content of 5%) for 4h to obtain bimetal 1% Pd 1% Cu/Al₂O₃A catalyst.

Example 2

1％Ni1％Cu/Al₂O₃The preparation of (1): 4.95g of alumina was first impregnated with 5g of Ni (NO)₃)₂With Cu (NO)₃)₂Stirring in solution, standing for 12h, drying at 80 deg.C for 12h, drying at 120 deg.C overnight, calcining at 500 deg.C in air for 4h, reducing at 550 deg.C in hydrogen atmosphere for 1h,the hydrogen flow rate was controlled at 120 ml/min. Cooling to room temperature after reduction, and adopting O2/N₂Mixed gas (O)₂Volume content of 5%) for 4h to obtain bimetal 1% Ni 1% Cu/Al₂O₃A catalyst.

Examples 3 to 6

Change of Cu (NO) in example 1₃)₂The other steps are the same as example 1, and 1% Pd 3% Cu/Al is prepared₂O₃、1％Pd5％Cu/Al₂O₃、1％Pd7％Cu/Al₂O₃、1％Pd10％Cu/Al₂O₃。

Examples 7 to 10

The catalyst 1% Ni 3% Cu/Al was prepared by changing the amount of the nickel precursor added in example 2 and the other steps were the same as in example 2₂O₃，1％Ni5％Cu/Al₂O₃、1％Ni7％Cu/Al₂O₃、1％Ni10％Cu/Al₂O₃。

Examples 11 to 14

Catalyst 1% Pd 10% Cu/Al₂O₃The carrier in (1) is prepared into 1 percent of Pd10 percent of Cu/AC and 1 percent of Pd10 percent of Cu/TiO respectively₂、1％Pd10％Cu/SiO₂、1％Pd10％Cu/ZSM-5。

Examples 15 to 18

Changing catalyst 1% Ni 10% Cu/Al₂O₃Respectively preparing the catalyst 1 percent of Ni10 percent of Cu/TiO₂、1％Ni10％Cu/SiO₂、1％Ni10％Cu/ZSM-5、1％Ni10％Cu/AC。

Example 19

The tubular reactor (internal diameter 10mm) was charged with a catalyst (20-40 mesh) in an amount of 0.25g, heated to 300 ℃ and charged with H₂The carrier gas was purged for one hour to activate the catalyst. Then adding 200mg/mL of reaction raw material (n-octane as a solvent) into a raw material bottle, cooling to 200 ℃, and adding H₂Introducing reaction raw materials into a tubular reactor for carrier gas to ensure that the reaction raw materials flow in a catalyst layer for reaction, controlling the flow rate of the carrier gas to be 10mL/min, connecting the tail part of the reactor with a collecting bottle at the flow rate of raw material solution (2.5mL/h), and collecting the bottleIce water cooling is adopted to ensure that the product is completely collected; the conversion rate and the product yield were quantitatively calculated by combining GC-MS, and different reaction results were obtained by changing the kind of catalyst and the reaction conditions, and the reaction results are shown in table 1.

TABLE 1 results of toluene synthesis from 3-cyclohexene carboxaldehyde catalyzed by copper-based catalyst

As can be seen from Table 1, the alumina carrier is 1% Pd 10% Cu/Al₂O₃The catalyst has the best effect, the temperature has obvious influence on the catalyst, the toluene yield is gradually increased by gradually increasing the temperature, and the toluene yield is not changed any more by increasing the temperature after the temperature is increased to 250 ℃, compared with 1% Ni 10% Cu/Al₂O₃At 250 ℃, the yield was lower and continued to increase the temperature, the yield increased, but still less than 1% Pd 10% Cu/Al₂O₃. The copper-palladium or copper-nickel bimetallic catalyst shows excellent catalyst performance in a certain temperature range, and the highest conversion rate of toluene can reach 94%.

Example 20

The catalyst prepared in example 6 was 1% Pd 10% Cu/Al₂O₃The reaction temperature was 250 ℃ and the 3-cyclohexene formaldehyde concentration was 50mg/mL, 100mg/mL, 300mg/mL, or 600mg/mL (n-octane was used as a solvent), and the reaction conditions were the same as in example 19, and the reaction results were as shown in Table 2.

TABLE 2 results of the reactions catalyzed by the catalyst at different concentrations

Comparative example 3

1％Pd1％Ir/Al₂O₃: the preparation method is described in patent document 20141072727249.2.

Comparative example 4

30％W₂C/AC: the preparation method is referred to patent document CN106883091A.

Comparative example 5

10％Cu/Al₂O₃Preparation of (1.9 g) Cu (NO)₃)₂。3H₂Dissolving O in water, diluting to 5g, stirring, standing for 12h, drying at 80 deg.C for 12h, drying at 120 deg.C overnight, calcining at 500 deg.C in air for 4h, reducing at 550 deg.C in hydrogen atmosphere for 1h, and controlling hydrogen flow rate at 120 ml/min. Cooling to room temperature after reduction, and adopting O2/N₂Passivating the mixed gas (O2 volume content is 5%) for 4h to obtain bimetal Cu/Al with 10%₂O₃A catalyst.

Comparative example 6

1％Pt/Al₂O₃: the preparation method is described in patent document 20141072727249.2.

Example 21

The reaction temperature is 250 ℃, and the catalysts are respectively 1% Pt/Al₂O₃、30％W₂C/AC、1％Pd/C、10％Cu/Al2O3、1％Pd1％Ir/Al₂O₃Otherwise, the reaction conditions were the same as in example 19, and the results are shown in Table 3.

TABLE 3 comparison of the activities of the different catalysts

The invention has simple reaction process in the process and high selectivity of target products, and the substrate can be obtained by one-step reaction by taking 1, 3-butadiene and acrolein which are derived from biomass resources as raw materialsA new method for producing aroma chemicals directly from biomass is presented. Under optimized conditions, 1% Pd 10% Cu/Al₂O₃The yield of toluene catalytically converted by the catalyst is up to 94%.