阅读说明：本技术 一种用于合成气与联苯/4-甲基联苯一步法甲基化的催化剂的制备方法和应用 (Preparation method and application of catalyst for one-step methylation of synthesis gas and biphenyl/4-methyl biphenyl ) 是由 代成义 赵潇 陈中顺 崔懿 唐玉 于 2020-12-31 设计创作，主要内容包括：一种用于合成气与联苯/4-甲基联苯一步法甲基化的催化剂的制备方法和应用,将硅源、铝源与碱源溶于水中,然后加入晶种,在温度为150～170℃下水热晶化1～3天,得到纳米ZSM-5分子筛,将ZSM-5纳米分子筛与硝酸铵溶液交换后焙烧,得到nano-HZSM-5分子筛；以nano-HSM-5分子筛为母体,采用等体积浸渍法进行化学改性,得到改性分子筛；将改性分子筛与金属氧化物混合即可。本发明利用合成气在金属氧化物上反应制得的甲醇等活性中间体即催化剂,与联苯/4-甲基联苯一步通过分子筛甲基化的双功能催化剂,从而实现一步法制备高附加值多环芳烃4,4’-二甲基联苯的方法。(Dissolving a silicon source, an aluminum source and an alkali source in water, then adding seed crystals, carrying out hydrothermal crystallization for 1-3 days at the temperature of 150-170 ℃ to obtain a nano ZSM-5 molecular sieve, exchanging the ZSM-5 nano molecular sieve with an ammonium nitrate solution, and then roasting to obtain a nano-HZSM-5 molecular sieve; using nano-HSM-5 molecular sieve as a matrix, and chemically modifying by an isometric impregnation method to obtain a modified molecular sieve; mixing the modified molecular sieve with metal oxide. The invention utilizes the active intermediates, namely the catalyst, such as methanol and the like prepared by the reaction of synthesis gas on metal oxide and the bifunctional catalyst for one-step methylation of biphenyl/4-methyl biphenyl by a molecular sieve, thereby realizing the method for preparing the polycyclic aromatic hydrocarbon 4,4' -dimethyl biphenyl with high added value by one-step method.)

1. A preparation method of a catalyst for one-step methylation of synthesis gas and biphenyl/4-methyl biphenyl is characterized by comprising the following steps:

1) dissolving a silicon source, an aluminum source and an alkali source in water, adding seed crystals, performing hydrothermal crystallization for 1-3 days at the temperature of 150-170 ℃ to obtain a nano ZSM-5 molecular sieve, exchanging the ZSM-5 nano molecular sieve with an ammonium nitrate solution, and roasting at the temperature of 500-540 ℃ for 4-6 hours to obtain a nano-HZSM-5 molecular sieve;

2) using nano-HSM-5 molecular sieve as a matrix, and chemically modifying by an isometric impregnation method to obtain a modified molecular sieve;

3) the modified molecular sieve is mixed with metal oxide to obtain the catalyst for one-step methylation of synthesis gas and biphenyl/4-methyl biphenyl.

2. The preparation method of the catalyst for one-step methylation of synthesis gas and biphenyl/4-methylbiphenyl according to claim 1, wherein the mass ratio of the modified molecular sieve to the metal oxide is 3: 7-7: 3; the molar ratio of water to silicon dioxide in the silicon source is (20-60) to 1; the mass of the seed crystal is 0.01-3% of the mass of the silicon dioxide in the silicon source; the metal oxide is an oxide consisting of two or three of Cu, Zn, Al, Cr, Zr, Ga, Cd and In.

3. The preparation method of the catalyst for one-step methylation of synthesis gas and biphenyl/4-methylbiphenyl according to claim 1, wherein the silicon source is ethyl orthosilicate, silica sol or white carbon black, the aluminum source is aluminum nitrate, sodium metaaluminate or aluminum isopropoxide, and the alkali source is sodium hydroxide or tetrapropylammonium hydroxide.

4. The method for preparing the catalyst for the one-step methylation of synthesis gas and biphenyl/4-methylbiphenyl according to claim 3, wherein the SiO is contained in the silicon source₂Al in aluminum source₂O₃Na in alkali source₂O、H₂The ratio of O is 0.1:0.1/x (0.01-0.03): (2-6), xThe silicon-aluminum ratio of nano-HSM-5 molecular sieve.

5. The preparation method of the catalyst for one-step methylation of synthesis gas and biphenyl/4-methylbiphenyl according to claim 3, wherein the mass of the seed crystal is 0.01-3% of the mass of the silica in the silicon source.

6. The preparation method of the catalyst for the one-step methylation of synthesis gas and biphenyl/4-methyl biphenyl according to claim 1, wherein the seed crystal is prepared by the following steps: mixing 10-60 g of tetraethoxysilane and 20-80 g of deionized water, stirring at 25-50 ℃ to hydrolyze the tetraethoxysilane, adding 50-100 g of tetrapropyl ammonium hydroxide, continuously stirring for 2 hours, carrying out hydrothermal treatment at 80-110 ℃ for 1-3 days, cooling, and collecting a white solution to obtain the seed crystal.

7. The preparation method of the catalyst for one-step methylation of synthesis gas and biphenyl/4-methylbiphenyl according to claim 1, wherein the modified molecular sieve in the step 2) is an M-nano-HZSM-5 catalyst, a Si-M-nano-HZSM-5 catalyst, a P-Si-M-nano-HZSM-5 catalyst or a Mg-P-Si-M-nano-HZSM-5 catalyst, and the specific preparation process comprises:

a) immersing the nano-HZSM-5 molecular sieve into a zinc nitrate, gallium nitrate, cerium nitrate or lanthanum nitrate solution, drying after immersing for 1-2h, and then roasting for 3-5h at 400-600 ℃ to obtain an M-nano-HZSM-5 catalyst; wherein M is Zn, Ga, Ce or La;

b) uniformly mixing cyclohexane and ethyl orthosilicate according to the volume ratio of 1:1, performing ultrasonic treatment for 0.5h, adding an M-nano-HZSM-5 catalyst, soaking for 1-2h, drying, and roasting at 400-600 ℃ for 3-5h to obtain an Si-M-nano-HZSM-5 catalyst;

c) soaking the Si-M-nano-HZSM-5 catalyst into a phosphoric acid solution with the mass concentration of 85%, drying after soaking for 1-2h, and then roasting for 3-5h at 400-600 ℃ to obtain a P-Si-M-nano-HZSM-5 catalyst;

d) uniformly mixing water and magnesium nitrate, carrying out ultrasonic treatment for 0.5h, adding a P-Si-M-nano-HZSM-5 catalyst, soaking for 1-2h, drying, and roasting at 400-600 ℃ for 3-5h to obtain the Mg-P-Si-M-nano-HZSM-5 catalyst.

8. The method for preparing the catalyst for the one-step methylation of synthesis gas and biphenyl/4-methylbiphenyl according to claim 7, wherein in the step a), the loading amount of M on the M-nano-HZSM-5 catalyst is 1% -3%;

in the step b), the mass of the Si element is 1-5% of that of the M-nano-HZSM-5 catalyst;

in the step c), the mass of the P element is 1-5% of that of Si-M-nano-HZSM-5;

in the step d), the mass ratio of the water to the P-Si-M-nano-HZSM-5 is 0.5: 1-1: 1; the mass of the Mg element is 1-3% of that of the P-Si-M-nano-HZSM-5 catalyst.

9. Use of a catalyst prepared according to the process of any one of claims 1 to 8 in the one-step methylation of synthesis gas with biphenyl or synthesis gas with 4-methylbiphenyl.

10. Use according to claim 9, characterized in that: introducing synthesis gas and biphenyl/4-methyl biphenyl into a fixed bed reactor filled with a catalyst, and reacting at 350-450 ℃ and 1-5 MPa to generate 4,4' -dimethyl biphenyl; wherein the volume of carbon monoxide and hydrogen in the synthesis gas is (0.1-8): 1, and the volume space velocity of the synthesis gas is 1000-50000 h^-1(ii) a The mass space velocity of biphenyl/4-methyl biphenyl is 0.1-5 h^-1；

Introducing the synthesis gas and biphenyl into a fixed bed reactor filled with a catalyst, and reacting at 350-450 ℃ and 1-5 MPa to generate 4-methyl biphenyl; wherein the volume of carbon monoxide and hydrogen in the synthesis gas is (0.1-8): 1, and the volume space velocity of the synthesis gas is 1000-50000 h^-1(ii) a The mass airspeed of the biphenyl is 0.1-5 h^-1。

Technical Field

The invention relates to the technical field of reaction of synthesis gas and biphenyl/4-methyl biphenyl, in particular to a preparation method and application of a catalyst for one-step methylation of synthesis gas and biphenyl/4-methyl biphenyl.

Background

At present, the research on alkylation of methanol and monocyclic aromatic hydrocarbon enters a relatively mature stage from the development and development of a catalyst to the discussion of a reaction mechanism, particularly the development of a shape-selective conversion process of methanol, benzene and toluene, and further leads the research on shape-selective catalysis to be mature. However, there is currently relatively little research on polycyclic aromatic hydrocarbons, particularly on alkylation of biphenyl. Due to more active sites of the polycyclic aromatic hydrocarbon reaction, the catalyst deactivation phenomenon is more serious than that of monocyclic aromatic hydrocarbon. In recent years, due to the rapid development of novel polymeric materials, the demand for polycyclic aromatic hydrocarbons is also gradually increased, so that the research on polycyclic aromatic hydrocarbons is more and more important.

4,4' -dialkylbiphenyl is an important raw material for synthesizing polymer materials with excellent performance. Among 4,4 '-dialkylbiphenyls, 4,4' -dimethylbiphenyl has attracted much attention because of its mild conditions and high utilization of carbon atoms during oxidation. The corresponding carboxylic acid generated after the oxidation of 4-biphenyl, 4,4' -dimethylbiphenyl is an important monomer of polymers such as artificial fiber, heat-resistant material, high-performance engineering plastic, thermotropic liquid crystal and the like. However, since the steric hindrance of the methyl group is small, selective synthesis of 4,4' -dimethylbiphenyl is difficult, and related research is relatively few. The traditional process route for methylating methanol and biphenyl/4-methyl biphenyl is that CO is selectively hydrogenated on a metal catalyst to synthesize the methanol, and then the methanol and the biphenyl/4-methyl biphenyl are methylated on a molecular sieve catalyst. Although the above two-step process is relatively mature, the following problems exist: firstly, the equilibrium conversion rate of methanol preparation from synthesis gas is low due to the limitation of thermodynamics, and a large amount of raw material gas needs to be circularly operated, so that the operation cost is increased; secondly, the self reaction of methanol (such as the preparation of olefin from methanol) is easier to carry out than the methylation of methanol and polycyclic aromatic hydrocarbon, so that a large amount of methanol cannot participate in the methylation reaction, the single-pass conversion rate of benzene is lower, and the methanol is easy to generate a large amount of carbon deposition precursors such as low-carbon olefin under the action of the catalyst, so that the catalyst is easy to deposit carbon and deactivate.

Disclosure of Invention

In order to overcome the problems in the prior art, the invention aims to provide a preparation method and application of a catalyst for one-step methylation of synthesis gas and biphenyl/4-methyl biphenyl.

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

a preparation method of a catalyst for one-step methylation of synthesis gas and biphenyl/4-methyl biphenyl comprises the following steps:

1) dissolving a silicon source, an aluminum source and an alkali source in water, adding seed crystals, performing hydrothermal crystallization for 1-3 days at the temperature of 150-170 ℃ to obtain a nano ZSM-5 molecular sieve, exchanging the ZSM-5 nano molecular sieve with an ammonium nitrate solution, and roasting at the temperature of 500-540 ℃ for 4-6 hours to obtain a nano-HZSM-5 molecular sieve;

2) using nano-HSM-5 molecular sieve as a matrix, and chemically modifying by an isometric impregnation method to obtain a modified molecular sieve;

3) the modified molecular sieve is mixed with metal oxide to obtain the catalyst for one-step methylation of synthesis gas and biphenyl/4-methyl biphenyl.

The invention further improves the following steps: the mass ratio of the modified molecular sieve to the metal oxide is 3: 7-7: 3; the molar ratio of water to silicon dioxide in the silicon source is (20-60) to 1; the mass of the seed crystal is 0.01-3% of the mass of the silicon dioxide in the silicon source; the metal oxide is an oxide consisting of two or three of Cu, Zn, Al, Cr, Zr, Ga, Cd and In.

The invention further improves the following steps: the metal oxide is ZnAlCrOx or ZnZrO_x、InZrO_x、ZnAlO_xOr ZnGaO_x。

The invention further improves the following steps: the silicon source is tetraethoxysilane, silica sol or white carbon black, the aluminum source is aluminum nitrate, sodium metaaluminate or aluminum isopropoxide, and the alkali source is sodium hydroxide or tetrapropylammonium hydroxide.

The invention further improves the following steps: SiO in silicon source₂Al in aluminum source₂O₃Na in alkali source₂O、H₂The ratio of O is 0.1:0.1/x (0.01-0.03): (2-6), and x is the silicon-aluminum ratio of the nano-HSM-5 molecular sieve.

The invention further improves the following steps: the mass of the seed crystal is 0.01-3% of the mass of the silicon dioxide in the silicon source.

The invention further improves the following steps: the seed crystal is prepared by the following processes: mixing 10-60 g of tetraethoxysilane and 20-80 g of deionized water, stirring at 25-50 ℃ to hydrolyze the tetraethoxysilane, adding 50-100 g of tetrapropyl ammonium hydroxide, continuously stirring for 2 hours, carrying out hydrothermal treatment at 80-110 ℃ for 1-3 days, cooling, and collecting a white solution to obtain the seed crystal.

The invention further improves the following steps: the modified molecular sieve in the step 2) is an M-nano-HZSM-5 catalyst, a Si-M-nano-HZSM-5 catalyst, a P-Si-M-nano-HZSM-5 catalyst or a Mg-P-Si-M-nano-HZSM-5 catalyst, and the specific preparation process comprises the following steps:

a) immersing the nano-HZSM-5 molecular sieve into a zinc nitrate, gallium nitrate, cerium nitrate or lanthanum nitrate solution, drying after immersing for 1-2h, and then roasting for 3-5h at 400-600 ℃ to obtain an M-nano-HZSM-5 catalyst; wherein M is Zn, Ga, Ce or La;

b) uniformly mixing cyclohexane and ethyl orthosilicate according to the volume ratio of 1:1, performing ultrasonic treatment for 0.5h, adding an M-nano-HZSM-5 catalyst, soaking for 1-2h, drying, and roasting at 400-600 ℃ for 3-5h to obtain an Si-M-nano-HZSM-5 catalyst;

c) soaking the Si-M-nano-HZSM-5 catalyst into a phosphoric acid solution with the mass concentration of 85%, drying after soaking for 1-2h, and then roasting for 3-5h at 400-600 ℃ to obtain a P-Si-M-nano-HZSM-5 catalyst;

d) uniformly mixing water and magnesium nitrate, carrying out ultrasonic treatment for 0.5h, adding a P-Si-M-nano-HZSM-5 catalyst, soaking for 1-2h, drying, and roasting at 400-600 ℃ for 3-5h to obtain the Mg-P-Si-M-nano-HZSM-5 catalyst.

The invention further improves the following steps: in the step a), the load capacity of M on the M-nano-HZSM-5 catalyst is 1% -3%;

in the step b), the mass of the Si element is 1-5% of that of the M-nano-HZSM-5 catalyst;

in the step c), the mass of the P element is 1-5% of that of Si-M-nano-HZSM-5;

in the step d), the mass ratio of the water to the P-Si-M-nano-HZSM-5 is 0.5: 1-1: 1; the mass of the Mg element is 1-3% of that of the P-Si-M-nano-HZSM-5 catalyst.

The application of the catalyst prepared by the method in one-step methylation of synthesis gas and biphenyl or synthesis gas and 4-methylbiphenyl.

The invention further improves the following steps: introducing synthesis gas and biphenyl/4-methyl biphenyl into a fixed bed reactor filled with a catalyst, and reacting at 350-450 ℃ and 1-5 MPa to generate 4,4' -dimethyl biphenyl; wherein the volume of carbon monoxide and hydrogen in the synthesis gas is (0.1-8): 1, and the volume space velocity of the synthesis gas is 1000-50000 h^-1(ii) a The mass space velocity of biphenyl/4-methyl biphenyl is 0.1-5 h^-1；

Introducing the synthesis gas and biphenyl into a fixed bed reactor filled with a catalyst, and reacting at 350-450 ℃ and 1-5 MPa to generate 4-methyl biphenyl; wherein the volume of carbon monoxide and hydrogen in the synthesis gas is (0.1-8): 1, and the volume space velocity of the synthesis gas is 1000-50000 h^-1(ii) a The mass airspeed of the biphenyl is 0.1-5 h^-1。

Compared with the prior art, the invention has the following beneficial effects:

the invention adopts synthesis gas to replace methanol as a novel methylating agent, and the synthesis gas and biphenyl/4-methyl biphenyl are efficiently converted on a metal-acid bifunctional catalyst, and the main route is that the synthesis gas is converted into active intermediates such as methanol and the like on the metal catalyst, and then the active intermediates and polycyclic aromatic hydrocarbon are subjected to methylation reaction on the acid site of a zeolite molecular sieve. Therefore, the methylation reaction of the synthesis gas and the biphenyl/4-methyl biphenyl is used for producing high value-added chemicals, and the method has the advantages of short process route, high biphenyl/4-methyl biphenyl conversion rate, high catalyst stability, high target product selectivity and the like, and is more economic and efficient.

The invention utilizes the active intermediates, namely the catalyst, such as methanol and the like prepared by the reaction of synthesis gas on metal oxide and the bifunctional catalyst for one-step methylation with biphenyl/4-methyl biphenyl through a molecular sieve, thereby realizing the method for preparing the polycyclic aromatic hydrocarbon 4,4' -dimethyl biphenyl with high added value by one step, and overcoming the defects of low biphenyl/4-methyl biphenyl conversion rate, low target product selectivity, more byproducts, quick catalyst inactivation, longer process flow and the like in the traditional methylation preparation of methanol and biphenyl/4-methyl biphenyl.

The concrete advantages are that:

1) the raw material synthesis gas has low cost and wide source, is prepared by a one-step method, has simple and efficient process route and obvious economic advantages:

2) advanced technical route, no three-waste discharge and zero process pollution.

3) Simple separation and purification and high product selectivity: the synthesis gas is used as a raw material, the byproducts such as polymethyl aromatic hydrocarbon and the like are less, and the components of reactants are simple and are beneficial to separation and purification.

4) The catalyst is prepared from non-noble metal, the preparation cost is low, and the industrialization is facilitated.

Drawings

FIG. 1 shows the results when the concentration of ZnAlCrO is 1g_x&Long-period results of methylation of syngas with biphenyl on nano-HZSM-5.

FIG. 2 shows the results of long-term methylation of methanol and biphenyl on 1g of nano-HZSM-5.

Detailed Description

The present invention will be described in further detail with reference to examples, but the scope of the present invention is not limited to these examples.

The catalyst of the invention is composed of metal oxide and solid acid. Wherein the metal oxide part consists of two or three of Cu, Zn, Al, Cr, Zr, Ga, Cd and In; the solid acid catalyst can be one of HZSM-5, HMCM-22, SAPO-11, HMOR and H beta molecular sieves.

The metal oxide in the invention is ZnAlCrOx, ZnZrO_x，InZrO_x，ZnAlO_xOr ZnGaO_xAnd the like.

The preparation method of the catalyst for one-step methylation of synthesis gas and biphenyl/4-methyl biphenyl comprises the following steps:

metal oxide moiety:

1) preparation of ZnAlCrOx metal oxide by coprecipitation method

Step 1: dissolving 0.01-0.04mol of zinc nitrate, 0.01-0.04mol of aluminum nitrate and 0.01-0.04mol of chromium nitrate in 140mL of 120-140mL of deionized water;

step 2: adding 18g of urea into the solution obtained in the step 1;

and step 3: heating to 90-110 ℃ under continuous stirring, and keeping for 8-12 h;

and 4, step 4: cooling, standing and aging overnight (12 h), then centrifuging and washing for multiple times, drying overnight at 100 ℃, and finally roasting at 400-600 ℃ for 4-6h to obtain the ZnAlCrOx metal oxide.

ZnZrO is simultaneously prepared by the method_x，InZrO_x，ZnAlO_x，ZnGaO_xAnd the like.

ZnZrO_xIs prepared by the following steps:

step 1: dissolving 0.01-0.04mol of zinc nitrate and 0.01-0.04mol of zirconium nitrate in 140mL of 120-140mL deionized water;

step 2: adding 18g of urea into the solution obtained in the step 1;

and step 3: heating to 90-110 ℃ under continuous stirring, and keeping for 8-12 h;

and 4, step 4: cooling, standing and aging overnight (12 h), centrifuging and washing for multiple times, drying at 100 ℃ overnight, and roasting at 400-600 ℃ for 4-6h to obtain ZnZrO_xA metal oxide.

Respectively replacing zinc nitrate in the steps with indium nitrate to prepare InZrO_xReplacing zirconium nitrate with aluminum nitrate to prepare ZnAlO_xReplacing zirconium nitrate with gallium nitrate to prepare ZnGaO_x。

2) Preparing a molecular sieve:

synthesis of seed crystal S-1: mixing 10-60 g of ethyl orthosilicate and 20-80 g of deionized water, adding the mixture into a three-neck round-bottom flask, putting magnetons into the flask, and transferring the flask into a constant-temperature water bath kettle; stirring for 1-2 hours at the temperature of 25-50 ℃ and the rotating speed of 200-400 r/min to completely hydrolyze ethyl orthosilicate, then adding 50-100 g of tetrapropyl ammonium hydroxide, continuously stirring for 2 hours, and then installing a serpentine condenser pipe. And finally, setting the temperature to be 80-110 ℃ for hydrothermal treatment for 1-3 days, cooling and collecting a white solution to obtain the seed crystal S-1.

Dissolving a silicon source (tetraethoxysilane, silica sol or white carbon black and the like), an aluminum source (aluminum nitrate, sodium metaaluminate or aluminum isopropoxide and the like) and an alkali source (sodium hydroxide or tetrapropylammonium hydroxide and the like) in a certain amount of water, mixing with a seed crystal S-1 (the mass of the seed crystal is 0.1% -3% of the mass of silicon dioxide in the silicon source), wherein the molar ratio of the water to the silicon dioxide in the silicon source is 20-60, and performing hydrothermal crystallization at the temperature of 150-. Exchanging the ZSM-5 nano molecular sieve with 0.1-1 mol/L ammonium nitrate solution for three times, washing, filtering and drying, and roasting at the temperature of 500-540 ℃ for 4-6h to convert nano-ZSM-5 into nano-HSM-5 molecular sieve, wherein the molecular sieve is marked as nano-HZSM-5.

Wherein, the molar ratio of the silicon source, the aluminum source, the alkali source and the water is SiO₂、Al₂O₃、Na₂O、H₂The ratio of O is 0.1:0.1/x (0.01-0.03) to (2-6), and x is the ratio of silicon and aluminum of nano-HZSM-5 molecular sieve.

HZSM-5 micron molecular sieves from the southern Kaiki university chemical reagent plant were purchased for comparison, and the HZSM-5 micron molecular sieves were labeled micro-HZSM-5.

3) The nano-HSM-5 molecular sieve is used as a matrix, and the molecular sieve is chemically modified by an isometric impregnation method.

The specific process is as follows: immersing a nano-HZSM-5 molecular sieve into a nitrate (zinc nitrate, gallium nitrate, cerium nitrate or lanthanum nitrate) solution, uniformly stirring by using a glass rod, standing for 1-2h, putting into an oven at 80 ℃ for 10h, drying, and roasting at 400-600 ℃ for 3-5h to obtain M (Zn, Ga, Ce, La) -nano-HZSM-5.

The loading amount of the metal elements on the nano-HZSM-5 molecular sieve is 1% -3% (namely the mass of the metal elements is 1-3% of that of the nano-HSM-5 molecular sieve).

And then sequentially modifying the M (Zn, Ga, Ce, La) -nano-HZSM-5 catalyst by tetraethoxysilane, phosphoric acid and magnesium nitrate to obtain Si, P and Mg modified catalysts, wherein the obtained catalysts are respectively marked as Si-M-nano-HZSM-5, P-Si-M-nano-HZSM-5 and Mg-P-Si-M-nano-HZSM-5. The method comprises the following specific steps:

1) silicon modification: uniformly mixing cyclohexane with the same mass as M-nano-HZSM-5 and tetraethoxysilane, performing ultrasonic treatment for 0.5h, adding an M-nano-HZSM-5 catalyst, uniformly stirring by using a glass cup, standing for 1-2h, putting into an oven at 80 ℃ for 10h, and roasting the dried catalyst at 400-600 ℃ for 3-5h to obtain Si-M-nano-HZSM-5.

Wherein the mass of the Si element in the added tetraethoxysilane is 1-5% of that of the M-nano-HZSM-5 catalyst.

2) Phosphorus modification: soaking Si-M-nano-HZSM-5 into 85% phosphoric acid solution, uniformly stirring by using a glass rod, standing for 1-2h, putting into an oven at 80 ℃ for 10h, and roasting the dried catalyst at 400-600 ℃ for 3-5 h. Obtaining P-Si-M-nano-HZSM-5; wherein the mass of the P element is 1-5% of that of Si-M-nano-HZSM-5;

3) modification of magnesium: uniformly mixing water with the same mass as P-Si-M-nano-HZSM-5 with magnesium nitrate, performing ultrasonic treatment for 0.5h, then pouring the P-Si-M-nano-HZSM-5 into the mixed solution, uniformly stirring the mixture by using a glass cup, standing the mixture for 1 to 2h, then putting the mixture into an oven with the temperature of 80 ℃ for 10h, and then roasting the dried catalyst for 3 to 5h at the temperature of 400 to 600 ℃ to obtain Mg-P-Si-M-nano-HZSM-5.

Wherein the mass of Mg element in the added magnesium nitrate is 1-3% of that of the P-Si-M-nano-HZSM-5 catalyst.

Evaluation of catalyst:

selecting metal oxide (such as ZnAlCrOx, ZnZrO)_x，InZrO_x，ZnAlO_xAnd ZnGaO_xEtc.) and molecular sieves (such as HZSM-5, HMCM-22, SAPO-11, HMOR, Hbeta and modified HZSM-5) are mixed by mass and tableted into a 20-40 mesh metal-molecular sieve bifunctional catalyst. Clothes (CN)1g of the metal-molecular sieve bifunctional catalyst is filled for testing the catalytic performance. The catalyst does not need reduction, the reaction temperature is 300-450 ℃, and the pressure is 1-5 MPa. The feed gas consists of CO and H₂(H₂1-3 of/CO, and the space velocity (GHSV) is 3600 mL/(g)_catH); polycyclic aromatic hydrocarbon (such as biphenyl or 4-methyl biphenyl) is dissolved in trimethylbenzene, and is pumped into a fixed bed by an advection pump under pressure, and the hourly space velocity of polycyclic aromatic hydrocarbon liquid is 1h^-1。

Specific examples are as follows.

Example 1 ZnAlCrO_x&The nano-HZSM-5 is prepared by the following steps:

ZnAlCrOx metal oxide is prepared by a coprecipitation method, 0.024mol of zinc nitrate, 0.008mol of aluminum nitrate and 0.008mol of chromium nitrate are dissolved in 140mL of deionized water; adding 18g of urea to the solution; heating to 110 ℃ under continuous stirring, and keeping for 10 h; cooling, standing and aging overnight (12 h), then centrifuging and washing for multiple times, drying overnight at 100 ℃, and finally roasting for 4h at 500 ℃ to obtain the ZnAlCrOx metal oxide.

Dissolving sodium metaaluminate and sodium hydroxide in a certain amount of water, gradually dropping the sodium metaaluminate and the sodium hydroxide into silica sol under stirring, finally dropping seed crystals S-1, performing hydrothermal crystallization for 3 days at the temperature of 170 ℃, centrifuging and drying the solution overnight, grinding the solution, and roasting the ground solution at the temperature of 540 ℃ for 6 hours to obtain the nano-ZSM-5 molecular sieve. Exchanging the nano-ZSM-5 molecular sieve with 0.2mol/L ammonium nitrate solution for three times, washing, filtering, drying overnight, and roasting at 500 ℃ for 4h to obtain the nano-HSM-5 molecular sieve. Wherein SiO is₂、Al₂O₃、Na₂O、H₂O molar ratio of 0.1SiO₂:0.1/23Al₂O₃:0.02Na₂O:4H₂And O, wherein the mass of the seed crystal is 1% of that of the silicon dioxide in the silicon source.

Synthesis of seed crystal S-1: mixing 50g of ethyl orthosilicate and 30g of deionized water, adding the mixture into a three-neck round-bottom flask, putting magnetons into the flask, and transferring the flask into a constant-temperature water bath kettle; stirring for 2 hours at the temperature of 35 ℃ and the rotating speed of 400 r/min to completely hydrolyze the tetraethoxysilane, then adding 70g of tetrapropylammonium hydroxide, continuing stirring for 2 hours, and then installing a serpentine condenser tube. Finally, the temperature is set to 80 ℃ for hydrothermal treatment for 3 days, and white solution is collected by cooling to obtain the seed crystal S-1.

0.6g of ZnAlCrOx metal oxide and 0.6g of nano-HZSM-5 molecular sieve are weighed and ground in an agate mortar for 30 minutes to be uniformly mixed. Then putting the mixed powder into a tablet machine, tabletting and screening to obtain ZnAlCrO with 20-40 meshes_x&nano-HZSM-5 particles.

Example 2 ZnZrO_x&Preparation of nano-HZSM-5

ZnZrO_xThe metal oxide is prepared by a coprecipitation method, and 0.004mol of zinc nitrate and 0.036mol of zirconium nitrate are dissolved in 140mL of deionized water; adding 18g of urea to the solution; heating to 110 ℃ under continuous stirring, and keeping for 10 h; cooling, standing and aging overnight (12 h), centrifuging and washing for multiple times, drying at 100 ℃ overnight, and roasting at 400 ℃ for 5h to obtain ZnZrO_xA metal oxide.

The preparation method of nano-HZSM-5 is the same as that of example 1.

0.6g of ZnZrO was weighed out_xThe metal oxide was mixed with 0.6g of nano-HZSM-5 molecular sieve by grinding in an agate mortar for 30 minutes. Then putting the mixed powder into a tablet machine, tabletting and screening to obtain ZnZrO with 20-40 meshes_x&nano-HZSM-5 particles.

Example 3 InZrO_x&Preparation of nano-HZSM-5

InZrO by Process of example 2_xA metal oxide; the amount of indium nitrate was 0.004mol and the amount of zirconium nitrate was 0.036 mol.

The preparation method of nano-HZSM-5 is the same as that of example 1.

0.6g of the above-mentioned InZrO was weighed_xThe metal oxide was mixed with 0.6g of nano-HZSM-5 molecular sieve by grinding in an agate mortar for 30 minutes. Then putting the mixed powder into a tablet machine, and sieving the mixed powder through tabletting to obtain InZrO powder with 20-40 meshes_x&nano-HZSM-5 particles.

Example 4 ZnAlO_x&Preparation of nano-HZSM-5

By means ofZnAlO was prepared by the method of example 2_xA metal oxide; the amount of zinc nitrate was 0.004mol and the amount of aluminum nitrate was 0.036 mol.

The preparation method of nano-HZSM-5 is the same as that of example 1.

Weighing the 0.6g of ZnAlO_xThe metal oxide was mixed with 0.6g of nano-HZSM-5 molecular sieve by grinding in an agate mortar for 30 minutes. Then putting the mixed powder into a tablet machine, tabletting and screening to obtain ZnAlO with 20-40 meshes_x&nano-HZSM-5 particles.

Example 5 ZnGaO_x&Preparation of nano-HZSM-5

ZnGaO was prepared by the method of example 2_xA metal oxide; the amount of zinc nitrate was 0.004mol and the amount of gallium nitrate was 0.036 mol.

The preparation method of nano-HZSM-5 is the same as that of example 1.

Weighing the above 0.6g ZnGaO_xThe metal oxide was mixed with 0.6g of nano-HZSM-5 molecular sieve by grinding in an agate mortar for 30 minutes. Then putting the mixed powder into a tablet machine, tabletting and screening to obtain ZnGaO with 20-40 meshes_x&nano-HZSM-5 particles.

Example 6 ZnAlCrO_x&Preparation of micro-HZSM-5

ZnAlCrO_xThe metal oxide was prepared in the same manner as in example 1.

The micro-HZSM-5 is commercial micron HZSM-5.

Weighing the 0.6g ZnAlCrO_xThe metal oxide was uniformly mixed with 0.6g of micro-HZSM-5 molecular sieve by grinding in an agate mortar for 30 minutes. Then putting the mixed powder into a tablet machine, tabletting and screening to obtain ZnAlCrO with 20-40 meshes_x&micro-HZSM-5 particles.

Example 7 ZnAlCrO_x&Preparation of HMCM-22

ZnAlCrO_xProcess for preparing metal oxide

The same as in example 1.

HMCM-22 is a commercial molecular sieve.

Weighing the 0.6g ZnAlCrO_xThe metal oxide was mixed homogeneously with 0.6g of HMCM-22 molecular sieve by grinding in an agate mortar for 30 minutes. Then putting the mixed powder into a tablet machine, tabletting and screening to obtain ZnAlCrO with 20-40 meshes_x&HMCM-22 particles.

Example 8 ZnAlCrO_x&Preparation of SAPO-11

ZnAlCrO_xThe metal oxide was prepared in the same manner as in example 1.

SAPO-11 is a commercial molecular sieve.

Weighing the 0.6g ZnAlCrO_xThe metal oxide was mixed with 0.6g of SAPO-11 molecular sieve by grinding in an agate mortar for 30 minutes. Then putting the mixed powder into a tablet machine, tabletting and screening to obtain ZnAlCrO with 20-40 meshes_x&SAPO-11 particles.

Example 9 ZnAlCrO_x&Preparation of HMOR

ZnAlCrO_xThe metal oxide was prepared in the same manner as in example 1.

HMOR is a commercial molecular sieve.

Weighing the 0.6g ZnAlCrO_xThe metal oxide was mixed homogeneously with 0.6g of HMOR molecular sieve by grinding in an agate mortar for 30 minutes. Then putting the mixed powder into a tablet machine, tabletting and screening to obtain ZnAlCrO with 20-40 meshes_x&HMOR particles.

Example 10 ZnAlCrO_x&Preparation of H beta

ZnAlCrO_xThe metal oxide was prepared in the same manner as in example 1.

H β is a commercial molecular sieve.

Weighing the 0.6g ZnAlCrO_xThe metal oxide was mixed with 0.6g of H β molecular sieve by grinding in an agate mortar for 30 minutes. Then putting the mixed powder into a tablet machine, tabletting and screening to obtain ZnAlCrO with 20-40 meshes_x&H beta particles.

Example 11 ZnAlCrO_x&Preparation of Ce-nano-HZSM-5

ZnAlCrO_xThe metal oxide was prepared in the same manner as in example 1.

The preparation method of nano-HZSM-5 is the same as that of example 1. Immersing a nano-HZSM-5 molecular sieve into a cerium nitrate solution, uniformly stirring by using a glass rod, standing for 2 hours, putting into an oven at 80 ℃ for 10 hours, drying, and roasting at 500 ℃ for 4 hours to obtain Ce-nano-HZSM-5; the loading of Ce was 3%.

Weighing the 0.6g ZnAlCrO_xThe metal oxide was uniformly mixed with 0.6g of Ce-nano-HZSM-5 molecular sieve by grinding in an agate mortar for 30 minutes. Then putting the mixed powder into a tablet machine, tabletting and screening to obtain ZnAlCrO with 20-40 meshes_x&Ce-nano-HZSM-5 particles.

Example 12 ZnAlCrO_x&Preparation of La-nano-HZSM-5

ZnAlCrO_xThe metal oxide was prepared in the same manner as in example 1.

The cerium nitrate in example 11 was replaced with lanthanum nitrate to prepare La-nano-HZSM-5; the supported amount of La was 3%.

Weighing the 0.6g ZnAlCrO_xThe metal oxide was uniformly mixed with 0.6g of La-nano-HZSM-5 molecular sieve by grinding in an agate mortar for 30 minutes. Then putting the mixed powder into a tablet machine, tabletting and screening to obtain ZnAlCrO with 20-40 meshes_x&La-nano-HZSM-5 particles.

Example 13 ZnAlCrO_x&Preparation of Ga-nano-HZSM-5

ZnAlCrO_xThe metal oxide was prepared in the same manner as in example 1.

The cerium nitrate in example 11 was replaced with gallium nitrate to prepare Ga-nano-HZSM-5; the supported amount of Ga was 3%.

Weighing the 0.6g ZnAlCrO_xThe metal oxide was uniformly mixed with 0.6g of Ga-nano-HZSM-5 molecular sieve by grinding in an agate mortar for 30 minutes. Then putting the mixed powder into a tablet machine, tabletting and screening to obtain ZnAlCrO with 20-40 meshes_x&Ga-nano-HZSM-5 particles.

Example 14 ZnAlCrO_x&Preparation of Zn-nano-HZSM-5

ZnAlCrO_xProcess for preparing metal oxideThe same as in example 1.

Zn-nano-HZSM-5 was prepared by replacing cerium nitrate in example 11 with zinc nitrate; the Zn supporting amount was 3%.

Weighing the 0.6g ZnAlCrO_xThe metal oxide was uniformly mixed with 0.6g of Zn-nano-HZSM-5 molecular sieve by grinding in an agate mortar for 30 minutes. Then putting the mixed powder into a tablet machine, tabletting and screening to obtain ZnAlCrO with 20-40 meshes_x&Zn-nano-HZSM-5 particles.

Example 15 ZnAlCrO_x&Preparation of Si-Ce-nano-HZSM-5

ZnAlCrO_xThe metal oxide was prepared in the same manner as in example 1.

Uniformly mixing cyclohexane and tetraethoxysilane according to the volume ratio of 1:1, performing ultrasonic treatment for 0.5h, adding the Ce-nano-HZSM-5 catalyst prepared in example 11, soaking for 2h, drying, and roasting at 500 ℃ for 4h to obtain the Si-Ce-nano-HZSM-5 catalyst; the mass of the Si element is 3 percent of that of the Ce-nano-HZSM-5 catalyst;

weighing the 0.6g ZnAlCrO_xThe metal oxide was uniformly mixed with 0.6g of Si-Ce-nano-HZSM-5 molecular sieve by grinding in an agate mortar for 30 minutes. Then putting the mixed powder into a tablet machine, tabletting and screening to obtain ZnAlCrO with 20-40 meshes_x&Si-Ce-nano-HZSM-5 particles.

Example 16 ZnAlCrO_x&Preparation of P-Si-Ce-nano-HZSM-5

ZnAlCrO_xThe metal oxide was prepared in the same manner as in example 1.

Soaking the Si-Ce-nano-HZSM-5 catalyst into a phosphoric acid solution with the mass concentration of 85%, drying after soaking for 2h, and roasting for 4h at 500 ℃ to obtain a P-Si-Ce-nano-HZSM-5 catalyst; the mass of the P element is 3 percent of that of the Si-Ce-nano-HZSM-5.

Weighing the 0.6g ZnAlCrO_xThe metal oxide was mixed with 0.6g of P-Si-Ce-nano-HZSM-5 molecular sieve by grinding in an agate mortar for 30 minutes. Then putting the mixed powder into a tablet machine, tabletting and screening to obtain ZnAlCrO with 20-40 meshes_x&P-Si-Ce-nano-HZSM-5 particles。

Example 17 ZnAlCrO_x&Preparation of Mg-P-Si-Ce-nano-HZSM-5

ZnAlCrO_xThe metal oxide was prepared in the same manner as in example 1.

Uniformly mixing water and magnesium nitrate, carrying out ultrasonic treatment for 0.5h, adding a P-Si-M-nano-HZSM-5 catalyst, soaking for 2h, drying, and roasting at 500 ℃ for 4h to obtain the Mg-P-Si-M-nano-HZSM-5 catalyst. The mass ratio of the water to the P-Si-M-nano-HZSM-5 is 1: 1; the mass of the Mg element is 2 percent of that of the P-Si-M-nano-HZSM-5 catalyst.

Weighing the 0.6g ZnAlCrO_xThe metal oxide was mixed with 0.6g of Mg-P-Si-Ce-nano-HZSM-5 molecular sieve by grinding in an agate mortar for 30 minutes. And then putting the mixed powder into a tablet machine, tabletting and screening to obtain the Mg-P-Si-Ce-nano-HZSM-5 particles with the particle size of 20-40 meshes.

Example 18

1) The seed crystal is prepared by the following processes: mixing 10g of tetraethoxysilane and 20g of deionized water, stirring at 25 ℃ to hydrolyze the tetraethoxysilane, adding 100g of tetrapropylammonium hydroxide, continuously stirring for 2 hours, carrying out hydrothermal treatment at 80 ℃ for 3 days, cooling, and collecting a white solution to obtain the seed crystal.

Dissolving a silicon source, an aluminum source and an alkali source in water, adding seed crystals, performing hydrothermal crystallization for 3 days at the temperature of 150 ℃ to obtain a nano ZSM-5 molecular sieve, exchanging the ZSM-5 nano molecular sieve with an ammonium nitrate solution, and roasting for 6 hours at the temperature of 500 ℃ to obtain a nano-HZSM-5 molecular sieve; wherein the molar ratio of the water to the silicon dioxide in the silicon source is 20: 1; the mass of the seed crystal is 0.01 percent of the mass of the silicon dioxide in the silicon source; the silicon source is tetraethoxysilane, the aluminum source is aluminum nitrate, and the alkali source is sodium hydroxide.

2) Using nano-HSM-5 molecular sieve as a matrix, and chemically modifying by an isometric impregnation method to obtain a modified molecular sieve; the specific process is as follows:

a) immersing the nano-HZSM-5 molecular sieve into a zinc nitrate solution, drying after immersing for 1h, and then roasting for 5h at 400 ℃ to obtain an M-nano-HZSM-5 catalyst; wherein M is Zn; the loading amount of M on the M-nano-HZSM-5 catalyst is 1 percent;

3) 0.6g of modified molecular sieve is mixed with metal oxide ZnAlCrOx to obtain the catalyst for one-step methylation of synthesis gas and biphenyl/4-methyl biphenyl. Wherein the mass ratio of the modified molecular sieve to the metal oxide is 1: 1.

the application comprises the following steps: introducing the synthesis gas and biphenyl into a fixed bed reactor filled with a catalyst, and reacting at 350 ℃ and 2MPa to generate 4,4' -dimethylbiphenyl; wherein the volume of carbon monoxide and hydrogen in the synthesis gas is 0.1:1, and the volume space velocity of the synthesis gas is 50000h^-1(ii) a The mass space velocity of biphenyl is 0.1h^-1。

Example 19

1) The seed crystal is prepared by the following processes: mixing 30g of tetraethoxysilane and 40g of deionized water, stirring at the temperature of 30 ℃ to hydrolyze the tetraethoxysilane, adding 50g of tetrapropylammonium hydroxide, continuously stirring for 2 hours, carrying out hydrothermal treatment at the temperature of 110 ℃ for 1 day, cooling, and collecting a white solution to obtain the seed crystal.

Dissolving a silicon source, an aluminum source and an alkali source in water, adding seed crystals, performing hydrothermal crystallization for 2 days at 160 ℃ to obtain a nano ZSM-5 molecular sieve, exchanging the ZSM-5 nano molecular sieve with an ammonium nitrate solution, and roasting at 540 ℃ for 4 hours to obtain a nano-HZSM-5 molecular sieve; wherein the molar ratio of the water to the silicon dioxide in the silicon source is 30: 1; the mass of the seed crystal is 0.1 percent of the mass of the silicon dioxide in the silicon source; the silicon source is silica sol, the aluminum source is sodium metaaluminate, and the alkali source is tetrapropylammonium hydroxide.

2) Using nano-HSM-5 molecular sieve as a matrix, and chemically modifying by an isometric impregnation method to obtain a modified molecular sieve; the specific process is as follows:

a) immersing a nano-HZSM-5 molecular sieve into a gallium nitrate solution, drying after immersing for 1h, and then roasting for 5h at 400 ℃ to obtain an M-nano-HZSM-5 catalyst; wherein M is Ga; the loading amount of M on the M-nano-HZSM-5 catalyst is 1 percent;

b) uniformly mixing cyclohexane and ethyl orthosilicate according to the volume ratio of 1:1, performing ultrasonic treatment for 0.5h, adding an M-nano-HZSM-5 catalyst, soaking for 2h, drying, and roasting at 500 ℃ for 4h to obtain an Si-M-nano-HZSM-5 catalyst; wherein the mass of the Si element is 2 percent of that of the M-nano-HZSM-5 catalyst;

3) 0.6g of modified molecular sieve and metal oxide ZnZrO_xMixing to obtain the catalyst for one-step methylation of the synthetic gas and the biphenyl/4-methyl biphenyl. Wherein the mass ratio of the modified molecular sieve to the metal oxide is 7: 3.

The application comprises the following steps: introducing the synthesis gas and 4-methyl biphenyl into a fixed bed reactor filled with a catalyst, and reacting at the temperature of 450 ℃ and the pressure of 2MPa to generate 4,4' -dimethyl biphenyl; wherein the volume of carbon monoxide and hydrogen in the synthesis gas is 1:1, and the volume space velocity of the synthesis gas is 20000h^-1(ii) a The mass space velocity of the 4-methyl biphenyl is 5h^-1。

Example 20

1) The seed crystal is prepared by the following processes: mixing 50g of tetraethoxysilane and 80g of deionized water, stirring at the temperature of 40 ℃ to hydrolyze the tetraethoxysilane, adding 60g of tetrapropylammonium hydroxide, continuously stirring for 2 hours, carrying out hydrothermal treatment at the temperature of 100 ℃ for 2 days, cooling, and collecting a white solution to obtain the seed crystal.

Dissolving a silicon source, an aluminum source and an alkali source in water, adding seed crystals, performing hydrothermal crystallization for 1 day at the temperature of 170 ℃ to obtain a nano ZSM-5 molecular sieve, exchanging the ZSM-5 nano molecular sieve with an ammonium nitrate solution, and roasting for 3 hours at the temperature of 520 ℃ to obtain a nano-HZSM-5 molecular sieve; wherein the molar ratio of the water to the silicon dioxide in the silicon source is 50: 1; the mass of the seed crystal is 3% of that of silicon dioxide in the silicon source; the silicon source is white carbon black, the aluminum source is aluminum isopropoxide, and the alkali source is tetrapropylammonium hydroxide.

2) Using nano-HSM-5 molecular sieve as a matrix, and chemically modifying by an isometric impregnation method to obtain a modified molecular sieve; the specific process is as follows:

a) immersing a nano-HZSM-5 molecular sieve into a cerium nitrate solution, drying after immersing for 2h, and then roasting at 600 ℃ for 3h to obtain an M-nano-HZSM-5 catalyst; wherein M is Ce; the loading amount of M on the M-nano-HZSM-5 catalyst is 1 percent;

b) uniformly mixing cyclohexane and ethyl orthosilicate according to the volume ratio of 1:1, performing ultrasonic treatment for 0.5h, adding an M-nano-HZSM-5 catalyst, soaking for 2h, drying, and roasting at 600 ℃ for 3h to obtain an Si-M-nano-HZSM-5 catalyst; wherein the mass of the Si element is 5 percent of that of the M-nano-HZSM-5 catalyst;

c) soaking the Si-M-nano-HZSM-5 catalyst into a phosphoric acid solution with the mass concentration of 85%, drying after soaking for 2h, and then roasting for 3h at 600 ℃ to obtain a P-Si-M-nano-HZSM-5 catalyst; wherein the mass of the P element is 1 percent of that of the Si-M-nano-HZSM-5;

3) 0.6g of modified molecular sieve and metal oxide ZnZrO_xMixing to obtain the catalyst for one-step methylation of the synthetic gas and the biphenyl/4-methyl biphenyl. Wherein the mass ratio of the modified molecular sieve to the metal oxide is 2: 1.

The application comprises the following steps: introducing the synthesis gas and biphenyl into a fixed bed reactor filled with a catalyst, and reacting at 400 ℃ and 5MPa to generate 4-methylbiphenyl; wherein the volume of carbon monoxide and hydrogen in the synthesis gas is 8:1, and the volume space velocity of the synthesis gas is 1000h^-1(ii) a The mass space velocity of biphenyl is 0.7h^-1。

Example 21

1) The seed crystal is prepared by the following processes: mixing 60g of tetraethoxysilane and 70g of deionized water, stirring at 50 ℃ to hydrolyze the tetraethoxysilane, adding 80g of tetrapropylammonium hydroxide, continuously stirring for 2 hours, carrying out hydrothermal treatment at 90 ℃ for 2 days, cooling, and collecting a white solution to obtain the seed crystal.

Dissolving a silicon source, an aluminum source and an alkali source in water, adding seed crystals, performing hydrothermal crystallization for 1 day at the temperature of 170 ℃ to obtain a nano ZSM-5 molecular sieve, exchanging the ZSM-5 nano molecular sieve with an ammonium nitrate solution, and roasting for 3 hours at 530 ℃ to obtain a nano-HZSM-5 molecular sieve; wherein the molar ratio of the water to the silicon dioxide in the silicon source is 20: 1; the mass of the seed crystal is 3% of that of silicon dioxide in the silicon source; the silicon source is tetraethoxysilane, the aluminum source is aluminum nitrate, and the alkali source is sodium hydroxide.

2) Using nano-HSM-5 molecular sieve as a matrix, and chemically modifying by an isometric impregnation method to obtain a modified molecular sieve; the specific process is as follows:

a) immersing a nano-HZSM-5 molecular sieve into a lanthanum nitrate solution, soaking for 1h, drying, and roasting at 450 ℃ for 4h to obtain an M-nano-HZSM-5 catalyst; wherein M is La; the loading amount of M on the M-nano-HZSM-5 catalyst is 1 percent;

b) uniformly mixing cyclohexane and ethyl orthosilicate according to the volume ratio of 1:1, performing ultrasonic treatment for 0.5h, adding an M-nano-HZSM-5 catalyst, soaking for 1h, drying, and roasting at 450 ℃ for 4h to obtain an Si-M-nano-HZSM-5 catalyst; wherein the mass of the Si element is 5 percent of that of the M-nano-HZSM-5 catalyst;

c) soaking the Si-M-nano-HZSM-5 catalyst into a phosphoric acid solution with the mass concentration of 85%, drying after soaking for 1h, and then roasting for 5h at 400 ℃ to obtain a P-Si-M-nano-HZSM-5 catalyst; wherein the mass of the P element is 1 percent of that of the Si-M-nano-HZSM-5;

d) uniformly mixing water and magnesium nitrate, carrying out ultrasonic treatment for 0.5h, adding a P-Si-M-nano-HZSM-5 catalyst, soaking for 1h, drying, and roasting at 600 ℃ for 3h to obtain the Mg-P-Si-M-nano-HZSM-5 catalyst. Wherein the mass ratio of the water to the P-Si-M-nano-HZSM-5 is 0.5: 1; the mass of the Mg element is 1 percent of that of the P-Si-M-nano-HZSM-5 catalyst.

3) 0.6g of the modified molecular sieve prepared in the step 2) and metal oxide ZnGaO are mixed_xMixing to obtain the catalyst for one-step methylation of the synthetic gas and the biphenyl/4-methyl biphenyl. Wherein the mass ratio of the modified molecular sieve to the metal oxide is 3: 7.

The application comprises the following steps: introducing the synthesis gas and biphenyl into a fixed bed reactor filled with a catalyst, and reacting at 380 ℃ and 3MPa to generate 4-methylbiphenyl; wherein the volume of carbon monoxide and hydrogen in the synthesis gas is 5:1, and the volume space velocity of the synthesis gas is 6000h^-1(ii) a The mass space velocity of biphenyl is 2h^-1。

Methylation of synthesis gas and biphenyl

1. ZnAlCrOx, ZnZrO prepared in examples 1 to 17 were selected_x，InZrO_x，ZnAlO_xAnd ZnGaO_xThe metal oxide and the nano-HZSM-5 molecular sieve are mixed by the mass of the metal oxide/the molecular sieve to prepare the catalyst.

Evaluation conditions were as follows: 450 ℃ and 3 MPa; the results of the evaluation are those of reaction 8h, see table 1:

table 1 evaluation results at 450 ℃ and 3MPa for 8 hours of reaction

2. Preferably, the ZnAlCrOx metal oxide is respectively mixed with nano-HZSM-5 and micro-HZSM-5 molecular sieves by the mass of the metal oxide/the molecular sieve and the like to prepare the catalyst. Evaluation conditions were as follows: 450 ℃ and 3 MPa; the results were evaluated as 8h of reaction, see table 2.

TABLE 2 evaluation results of the catalyst at 450 ℃ and 3MPa for 8 hours of reaction

3. Preferably, the ZnAlCrOx metal oxide is respectively mixed with nano-HZSM-5, HMCM-22, SAPO-11, HMOR and H beta molecular sieves by mass of metal oxide/molecular sieves to prepare the catalyst.

Evaluation conditions were as follows: 450 ℃ and 3 MPa; the results were evaluated as 8h of reaction, see table 3.

TABLE 3 evaluation results of the catalyst at 450 ℃ and 3MPa for 8 hours of reaction

4. Preferably, the ZnAlCrOx metal oxide is respectively mixed with nano-HZSM-5 and M ((Zn, Ga, Ce, La) -nano-HZSM-5 molecular sieves by the mass of metal oxide/molecular sieve to prepare the catalyst.

Evaluation conditions were as follows: 450 ℃ and 3 MPa; the results were evaluated as 8h of reaction, see table 4.

TABLE 4 evaluation results of the catalyst at 450 ℃ and 3MPa for 8 hours of reaction

5. Preferably, the ZnAlCrOx metal oxide is respectively mixed with Ce-nano-HZSM-5 and Si, P and Mg modified Ce-nano-HZSM-5 molecular sieves by the mass of metal oxide/molecular sieve and the like to prepare the catalyst.

Evaluation conditions were as follows: 450 ℃ and 3 MPa; the results were evaluated as 8h of reaction, see table 5.

TABLE 5 evaluation results of the catalyst at 450 ℃ and 3MPa for 8 hours of reaction

Methylation of synthesis gas with 4-methylbiphenyl:

preferably, the ZnAlCrOx metal oxide is respectively mixed with Ce, Si, P and Mg modified Ce-nano-HZSM-5 molecular sieve to prepare the catalyst by the mass of the metal oxide/the molecular sieve and the like.

Evaluation conditions were as follows: 450 ℃ and 3 MPa; the results were evaluated as 8h of reaction, see table 6.

TABLE 6 evaluation results of the catalyst at 450 ℃ and 3MPa for 8 hours of reaction

As can be seen from figure 1, the synthesis gas and biphenyl are catalyzed by ZnAlCrOx & nano-HZSM-5, no obvious inactivation is found after the reaction is carried out for 200 hours, the biphenyl conversion rate is kept above 40%, and the catalyst has high activity and is relatively stable.

As can be seen from fig. 2, under the same reaction conditions, the initial conversion of methanol and biphenyl on the nano-HZSM-5 catalyst was low, only about 20% of the conversion of biphenyl and the catalyst deactivation was severe, and almost completely deactivated after 30 hours of reaction. The above situation can show that not only can the conversion rate of biphenyl be improved, but also the stability of the catalyst can be improved by using the synthesis gas instead of methanol as a novel methylating agent.