Method for pipelined continuous synthesis of silane coupling agent and used N-heterocyclic carbene complex catalyst

Abstract

The invention belongs to the field of fine chemical engineering, and particularly relates to an N-heterocyclic carbene complex catalyst and application of the N-heterocyclic carbene complex catalyst in pipelined continuous synthesis of a silane coupling agent. The invention provides an N-heterocyclic carbene complex catalyst, which comprises a ligand and an active component, the ligand is an N-heterocyclic carbene ligand, and the active component is a transition metal; the molar ratio of the N-heterocyclic carbene ligand to the transition metal is 1: 1. The invention also provides a method for pipelined continuous synthesis of the silane coupling agent, which comprises the following steps: carrying out homogeneous hydrosilylation reaction in a pipelined reactor by taking hydrogen-containing silane and unsaturated hydrocarbon as raw materials in the presence of an N-heterocyclic carbene complex catalyst to obtain the silane coupling agent. The spatial configuration and the electronic property of the N-heterocyclic carbene ligand precursor are designed and regulated, so that the N-heterocyclic carbene ligand precursor is matched with transition metal, and the N-heterocyclic carbene ligand precursor can be applied to hydrosilylation reaction.

Description

Technical Field

[0001] The invention belongs to the field of fine chemicals, and in particular relates to an N-heterocyclic carbene complex catalyst and application thereof in pipeline continuous synthesis of a silane coupling agent. Background Art

[0002] There are many types of catalysts used in the hydrosilylation process, among which the noble metal platinum catalyst is the most typical. Currently, the most widely used is Karstedt's catalyst diluted with a specific diluent, the main component of which is a complex of platinum and vinyl. However, there are still disadvantages such as difficulty in recovery, high cost, and general selectivity, which leads to serious platinum losses in the industry. Transition metals such as manganese, iron, cobalt, nickel, copper, zinc, etc. are more abundant in resources, cheaper in cost, and more promising for industrial application, but their catalytic activity is often not as good as catalysts such as noble metals such as platinum and rhodium.

[0003] For this reason, N-heterocyclic carbene ligands have received extensive attention due to their stronger affinity, electron-donating ability and coordination ability. On the one hand, due to the strong electronegativity of nitrogen, the lone pair of electrons on the carbene carbon atom tends to be stable, which makes N-heterocyclic carbene ligands have stronger stability. On the other hand, the strong σ-electron-donating and weak π-accepting properties of N-heterocyclic carbene ligands make it easier to coordinate with metals, and can significantly improve the metal electron cloud density, thereby enhancing the metal catalytic activity. At present, the research is mainly N-heterocyclic carbene platinum complexes (CN106380488A, CN106380487A, CN106391121A, CN104324751A), N-heterocyclic carbene rhodium complexes (CN106140299A), that is, the current N-heterocyclic carbene complex catalysts are still precious metals platinum and rhodium. Due to a series of reasons such as selectivity, activity and stability, the widespread application of transition metals in N-heterocyclic carbene complex catalysts is limited.

[0004] Currently, there is a lack of design and application of complex catalysts formed by the coordination of N-heterocyclic carbene ligands with transition metals. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method for continuously synthesizing a silane coupling agent in a pipeline and an N-heterocyclic carbene complex catalyst used therein. The present invention provides a method for continuously preparing a silane coupling agent by a homogeneous hydrosilylation reaction by synthesizing a complex catalyst composed of an N-heterocyclic carbene ligand and a transition metal, which can improve production efficiency and reduce production costs.

[0006] In order to solve the above technical problems, the present invention provides an N-heterocyclic carbene complex catalyst, comprising a ligand and an active component, wherein the ligand is an N-heterocyclic carbene ligand, and the active component is a transition metal; the molar ratio of the N-heterocyclic carbene ligand to the transition metal is 1:1.

[0007] As an improvement of the N-heterocyclic carbene complex catalyst of the present invention, the precursor corresponding to the N-heterocyclic carbene ligand is any one of the following:

[0008]

[0009] As a further improvement of the N-heterocyclic carbene complex catalyst of the present invention, the transition metal is at least any one (ie, one or more) of the following: manganese, iron, cobalt, nickel, copper, zinc.

[0010] The present invention also provides a method for preparing an N-heterocyclic carbene complex catalyst, comprising the following steps:

[0011] Under the protection of an inert gas (such as nitrogen), a transition metal salt, an N-heterocyclic carbene ligand precursor and a solvent are added to a reaction container (Schlenk tube); the reaction is carried out under the protection of an inert gas, the reaction temperature is 80±10° C., the reaction time is 1±0.2 h, the reaction pressure is normal pressure, and the reaction product is post-treated to obtain an N-heterocyclic carbene complex catalyst;

[0012] The molar ratio of the metal in the transition metal salt to the N-heterocyclic carbene ligand precursor obtained in step 1) is 1:1.

[0013] As an improvement of the preparation method of the N-heterocyclic carbene complex catalyst of the present invention:

[0014] The transition metal salt is a metal hydrochloride; the metal hydrochloride is at least one of chloride salts of manganese, iron, cobalt, nickel, copper and zinc.

[0015] As a further improvement of the preparation method of the N-heterocyclic carbene complex catalyst of the present invention: the N-heterocyclic carbene ligand precursor is any one of the following:

[0016] 1-(2-pyridylmethyl)imidazole (L1), 1,3-bis(2-pyridylmethyl)imidazole chloride (L2), 1-(2-pyridylmethyl)-3-methylimidazole iodide (L3), 1,1′-dimethyl-3,3′-methylenediimidazole dibromide (L4), 1,1′-diisopropyl-3,3′-methylenediimidazole dibromide (L5), 1,1′-methylenebis(3-(pyridin-2-yl)-1H-imidazolium) dihexafluorophosphate (L6).

[0017] As a further improvement of the preparation method of the N-heterocyclic carbene complex catalyst of the present invention: the solvent is toluene.

[0018] Generally speaking, 100±50 mL of solvent is used for every 0.1 mol of N-heterocyclic carbene ligand precursor.

[0019] The present invention also provides a method for continuously synthesizing a silane coupling agent in a pipeline: a homogeneous hydrosilylation reaction is carried out in a pipeline reactor using an N-heterocyclic carbene complex catalyst and hydrogen-containing silane and an unsaturated hydrocarbon as raw materials to obtain the silane coupling agent.

[0020] That is, the present invention provides a synthesis method for preparing a silane coupling agent by continuous homogeneous hydrosilylation based on an N-heterocyclic carbene complex catalyst.

[0021] As an improvement of the method for pipeline continuous synthesis of silane coupling agent of the present invention, the method comprises the following steps:

[0022] 1) Addition: Hydrogen-containing silane and unsaturated hydrocarbon are pumped into a pipeline reactor (with an inner diameter of 10 to 30 mm and a tube length of 50 to 100 m) at a mass flow rate ratio of 1 to 2:1, and reacted at a temperature of 50 to 150° C. (preferably 70 to 120° C., more preferably 80 to 110° C.) and a pressure of 1 to 3 MPa (preferably 1.5 to 3 MPa) for 40 to 120 min (preferably 50 to 90 min). The reaction product flowing out of the pipeline reactor is a crude silane coupling agent product;

[0023] 2) Purify the crude silane coupling agent product and perform post-treatment (purification by reduced pressure distillation) to obtain the silane coupling agent.

[0024] Note: The reaction product flowing out of the pipeline reactor, the crude silane coupling agent, can be collected in a collection tank and then subjected to post-treatment such as reduced pressure distillation.

[0025] As a further improvement of the pipeline continuous synthesis method of silane coupling agent of the present invention: the hydrogen-containing silane is trimethoxysilane, triethoxysilane, trichlorosilane, tris(trimethylsiloxy)silane;

[0026] The unsaturated hydrocarbon is an olefin or an olefin derivative, the olefin is pentene or octene, and the olefin derivative is acrylamine, allyl methacrylate, allyl mercaptan, cyclohexane oxide ethylene, or allyl glycidyl ether.

[0027] All N-heterocyclic carbene ligand precursors in the present invention are known compounds, which are disclosed in the following articles:

[0028] From Simple Ligands to Complex Structures:Structural DiversityofSilver(I)Complexes Bearing Tetradentate(alkylene bimpy)NHC Ligands;

[0029] Ruthenium(II)complexes with N-heterocyclic carbene–phosphine ligandsfor the N-alkylation of amines with

[0030] Synthesis of nitrogen heterocyclic carbenes and their applications in hydrogen transfer reactions.

[0031] The specific synthesis can be carried out according to the following method:

[0032] 1. N-heterocyclic carbene ligand precursor 1-(2-pyridylmethyl)imidazole (L1):

[0033]

[0034] 0.1 mol of 2-chloromethylpyridine hydrochloride, 0.1 mol of imidazole, 0.2 mol of potassium hydroxide (i.e., the molar ratio of the three is 1:1:2) and 100 mL of tetrahydrofuran are added into a three-necked flask, and the mixture is stirred and reacted at 80°C for 20 h, and then the solvent (tetrahydrofuran) is removed by rotary evaporation. 15 mL of dichloromethane is added and filtered to remove the potassium chloride salt generated by the reaction, and an appropriate amount of anhydrous ether (about 30 mL) is added to the filtrate for recrystallization. The mixture is filtered through a Buchner funnel, and the filter cake is washed with anhydrous ether (3×30 mL) and then dried in a vacuum oven at 60°C for 4 h to obtain a reddish brown solid L1, i.e., 1-(2-pyridylmethyl)imidazole.

[0035] 2. N-heterocyclic carbene ligand precursor 1,3-bis(2-pyridylmethyl)imidazole chloride (L2):

[0036]

[0037] 0.2 mol of 2-chloromethylpyridine hydrochloride, 0.1 mol of imidazole, 0.3 mol of potassium hydroxide (i.e., the molar ratio of the three is 2:1:3) and 100 mL of tetrahydrofuran are added into a three-necked flask, and the reaction is stirred at 80°C for 20 h, and then the solvent (tetrahydrofuran) is removed by rotary evaporation. After adding 15 mL of dichloromethane, the potassium chloride salt generated by the reaction is removed by suction filtration, and an appropriate amount of anhydrous ether (about 30 mL) is added to the filtrate for recrystallization. The filtrate is filtered with a Buchner funnel, and the filter cake is washed with anhydrous ether (3×30 mL) and then dried in a vacuum oven at 60°C for 4 h to obtain a reddish brown solid L2, i.e., 1,3-bis(2-pyridylmethyl)imidazole chloride.

[0038] 3. N-heterocyclic carbene ligand precursor 1-(2-pyridylmethyl)-3-methylimidazole iodide (L3):

[0039]

[0040] 0.1 mol of 2-chloromethylpyridine hydrochloride, 0.1 mol of N-methylimidazole, 0.1 mol of potassium iodide (i.e., the molar ratio of the three is 1:1:1) and 100 mL of tetrahydrofuran are added into a three-necked flask, and the reaction is stirred at 70°C for 20 h, and the solvent (tetrahydrofuran) is removed by rotary evaporation. After adding 15 mL of dichloromethane, the potassium chloride salt generated by the reaction is removed by suction filtration, and an appropriate amount of anhydrous ether (about 30 mL) is added to the filtrate for recrystallization. The mixture is filtered through a Buchner funnel, and the filter cake is washed with anhydrous ether (3×30 mL) and dried in a vacuum oven at 60°C for 4 h to obtain a brick-red solid L3, i.e., 1-(2-pyridylmethyl)-3-methylimidazole iodide.

[0041] 4. N-heterocyclic carbene ligand precursor 1,1′-dimethyl-3,3′-methylenediimidazole dibromide (L4):

[0042]

[0043] 0.1 mol of dibromomethane, 0.2 mol of N-methylimidazole (i.e., the molar ratio of the two is 1:2) and 50 mL of tetrahydrofuran are added into a three-necked flask, and the mixture is stirred at 100°C for 20 h, and then the solvent (tetrahydrofuran) is removed by filtration. Recrystallization is carried out using methanol (about 15 mL), and the mixture is filtered using a Buchner funnel. The filter cake is washed with anhydrous ether (3×30 mL) and then dried in a vacuum oven at 60°C for 4 h to obtain a white solid L4, i.e., 1,1′-dimethyl-3,3′-methylenediimidazole dibromide.

[0044] 5. N-heterocyclic carbene ligand precursor 1,1′-diisopropyl-3,3′-methylenediimidazole dibromide (L5):

[0045]

[0046] 0.1 mol of dibromomethane, 0.2 mol of 1-isopropylimidazole (i.e., the molar ratio of the two is 1:2) and 50 mL of tetrahydrofuran are added into a three-necked flask, the reaction is stirred at 100°C for 20 h, and then the solvent (tetrahydrofuran) is removed, and recrystallization is carried out using methanol (15 mL), and the mixture is filtered through a Buchner funnel. The filter cake is washed with anhydrous ether (3×30 mL) and then dried in a vacuum oven at 60°C for 4 h to obtain a white solid L5, i.e., 1,1′-diisopropyl-3,3′-methylenediimidazole dibromide.

[0047] VI. N-heterocyclic carbene ligand precursor 1,1′-methylenebis(3-(pyridin-2-yl)-1H-imidazolium) dihexafluorophosphate (L6):

[0048]

[0049] 0.1 mol of dibromomethane, 0.2 mol of 2-(1H-imidazole-1-yl)pyridine (i.e., the molar ratio of the two is 1:2) and 50 mL of tetrahydrofuran are added into a three-necked flask, and the mixture is stirred at 100°C for 20 h, and then the solvent (tetrahydrofuran) is removed by suction. The filter cake obtained by suction filtration is dissolved in deionized water (30 mL), and ammonium hexafluorophosphate (about 24 g) is added to produce a white precipitate. The mixture is filtered through a Buchner funnel, and the filter cake is washed with anhydrous ether (3×30 mL) and dried in a vacuum oven at 60°C for 4 h to obtain a white solid L6, i.e., 1,1′-methylenebis(3-(pyridin-2-yl)-1H-imidazolium)dihexafluorophosphate.

[0050] The structures of the above N-heterocyclic carbene ligands can be confirmed by NMR analysis. The NMR data are as follows: N-heterocyclic carbene ligand L1:

[0051] 1 H NMR (400MHz, CDCl3) δ8.60(m,1H),7.70~7.60(m,2H),7.27~7.23(m,1H),7.13~7.00(m,2H),7.00~6.94(m,1H),5.26(s,2H); 13 C NMR (101MHz, CDCl3) δ156.0,149.6,137.5,137.2,129.9,122.9,121.0,119.4,52.4.

[0052] N-Heterocyclic Carbene Ligand L2:

[0053] 1H NMR (400MHz, CDCl3) δ10.90(s,1H),8.52(m,2H),7.73(m,4H),7.63(m,2H),7.29(m,2H),5.71(s,4H); 13 C NMR (101MHz, CDCl3) δ152.4,149.8,138.0,137.7,124.0,123.9,122.3,54.1.

[0054] N-Heterocyclic Carbene Ligand L3:

[0055] 1 H NMR (400MHz, DMSO-d6) δ9.27(s,1H),8.56(m,1H),7.91(m,1H),7.80(s,1H),7.76(s,1H),7.52(m,1H),7.41(m,1H),5.60(s,2H),3.91(s,3H); 13 C NMR (101MHz, DMSO-d6) δ153.9,149.9,137.8,137.5,123.9,123.4,122.8,53.2,36.2.

[0056] N-Heterocyclic Carbene Ligand L4:

[0057] 1 H NMR (400MHz, DMSO-d6) δ9.57(s,2H),8.10(s,2H),7.80(s,2H),6.77(s,2H),3.87(s,6H); 13 C NMR (101MHz, DMSO-d6) δ138.6,124.8,122.4,58.2,36.8.

[0058] N-Heterocyclic Carbene Ligand L5:

[0059] 1 H NMR (400MHz, DMSO-d6) δ9.80(s,1H),8.18(s,1H),8.03(s,1H),6.72(s,1H),4.66(p,1H),1.46(d,6H); 13 C NMR (101MHz, DMSO-d6) δ137.1,122.9,121.8,58.2,53.4,22.6.

[0060] N-Heterocyclic Carbene Ligand L6:

[0061] 1H NMR(400MHz,DMSO-d6)δ10.59(s,1H),8.71-8.68(m,1H),8.66(ddd,1H),8 .54-8.52(m,1H),8.25-8.17(m,2H),7.96-7.90(m,2H),7.68-7.57(m,4H); 13 C NMR (101MHz, DMSO-d6) δ149.8,146.8,141.1,135.1,134.7,130.7,126.0,122.8,120.5,115.4.

[0062] The invention designs and regulates the spatial configuration and electronic properties of the N-heterocyclic carbene ligand precursor, thereby achieving coordination with a transition metal and applying the N-heterocyclic carbene ligand precursor to a hydrosilylation reaction.

[0063] The N-heterocyclic carbene complex catalyst of the present invention is composed of an N-heterocyclic carbene ligand and a transition metal salt; the present invention utilizes the catalyst to carry out a homogeneous hydrosilylation reaction in a pipeline reactor with hydrosilane and unsaturated hydrocarbon as raw materials to prepare a series of silane coupling agents. The catalyst of the present invention has the technical advantages of good stability, wide substrate range, low production cost, simple preparation process, high yield, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings.

[0065] Figure 1 Schematic diagram of the silane coupling agent preparation device. DETAILED DESCRIPTION

[0066] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto:

[0067] Device Example 1: A pipeline reactor for preparing 3-(2,3-epoxypropoxy)propyltrimethoxysilane (KH-560), the structure of which is as follows: Figure 1 As shown: including pipeline reactor, hydrogen-containing silane raw material tank, unsaturated hydrocarbon raw material tank;

[0068] The outlet of the hydrogen-containing silane raw material tank is connected to the inlet of the collection pipe through a pipeline provided with a stop valve 1, a pump I, and a pipeline provided with a stop valve 3 in sequence; a stop valve 5 and a one-way valve are provided in sequence on the collection pipe according to the flow direction, and the function of the one-way valve is to prevent the material from flowing back;

[0069] The outlet of the unsaturated hydrocarbon raw material tank is connected to the inlet of the collecting pipe through a pipeline provided with a stop valve 2, a pump II, a pipeline provided with a stop valve 4 in sequence;

[0070] The nitrogen tank is connected to the inlet of the collecting pipe through a pipeline provided with a stop valve 8;

[0071] The outlet of the collecting pipe is connected to the inlet of the pipeline reactor, and the hydrogen inlet provided with a stop valve 6 is connected to the collecting pipe located between the one-way valve and the inlet of the pipeline reactor;

[0072] The outlet of the pipeline reactor is connected to the inlet of the collecting tank through a back pressure valve; the back pressure valve is used to control the reaction pressure of the pipeline reactor; the outlet of the collecting tank is connected to the outlet of the reaction liquid through a pipeline provided with a stop valve 7.

[0073] The actual working process is as follows:

[0074] The stop valves 1 to 6 are all in the open state, and the pumps I and II are both in the working state. The hydrosilane transported by the pump I and the unsaturated hydrocarbons transported by the pump II react in the pipeline reactor. After the reaction liquid flowing out of the pipeline reactor flows into the collection tank through the back pressure valve, the stop valve 7 can be opened to realize the discharge. After the subsequent purification treatment (purification by reduced pressure distillation), the product is obtained.

[0075] The products obtained in the following cases were verified by conventional NMR.

[0076] Catalyst Example 1, Preparation Method of N-Heterocyclic Carbene Complex Catalyst:

[0077] Under nitrogen protection, nickel chloride (12.96 g, 0.1 mol), N-heterocyclic carbene ligand precursor L4 (33.80 g, 0.1 mol) and solvent toluene (100 mL) were added to the Schlenk tube. After the Schlenk tube was degassed three times, the Schlenk tube was sealed under nitrogen and reacted at 80°C for 1 h. The reaction pressure was normal pressure. After the reaction was completed, the solvent (toluene) was removed by rotary evaporation, and the mixture was filtered with a Buchner funnel. The filter cake was washed with anhydrous ether (3×30 mL) and then dried in a vacuum oven at 60°C for 4 h to obtain an N-heterocyclic carbene complex catalyst.

[0078] The reaction formula is:

[0079]

[0080] Example 1-1, a method for preparing a continuous silane coupling agent 3-(2,3-epoxypropoxy)propyltrimethoxysilane using an N-heterocyclic carbene nickel complex as a catalyst, comprising the following steps:

[0081] 1. A catalyst is attached to the inner wall of a pipeline reactor, wherein the catalyst is the N-heterocyclic carbene complex catalyst prepared in Catalyst Example 1.

[0082] 2. Setting: The inner diameter of the pipeline reactor is 10 mm, the length of the tube is 70 m, and the inner wall is attached with N-heterocyclic carbene nickel complex as a catalyst. The amount of catalyst attached is about 0.05 g / cm 2 .

[0083] Trimethoxysilane and allyl glycidyl ether materials were pumped into the pipeline reactor at flow rates of 30 g / min and 20 g / min through pumps I and II, respectively. The reaction temperature was 100°C, and the reaction residence time was about 60 minutes. The pressure in the pipeline reactor was stabilized at 2 MPa by controlling the back pressure valve after the pipeline reactor. Finally, the reaction liquid flowed into the collection tank to obtain the crude silane coupling agent 3-(2,3-epoxypropoxy)propyltrimethoxysilane, which was purified by vacuum distillation, and the fractions at 125 to 127°C under a pressure of -97.3 kPa were collected to obtain the 3-(2,3-epoxypropoxy)propyltrimethoxysilane product (purity ≥ 99.5%).

[0084] When the dosage of trimethoxysilane and allyl glycidyl ether is 90 g and 60 g respectively, 122 g of 3-(2,3-epoxypropoxy)propyltrimethoxysilane product is obtained, and the calculation formula of the yield of 3-(2,3-epoxypropoxy)propyltrimethoxysilane is:

[0085]

[0086] Wherein, m2 is the product mass of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, and m1 is the amount of allyl glycidyl ether used.

[0087] When the reaction is finished, turn off pump I, stop valve 1 and pump II, stop valve 2, and stop valve 6, and open stop valve 8, and treat the device after the reaction as follows: use nitrogen to purge to remove excess materials in the pipeline reactor, and then cool the pipeline reactor to room temperature; thus preparing for the next reaction. This is a conventional treatment method.

[0088] Embodiments 1-2 to 1-36,

[0089] The type of N-heterocyclic carbene ligand precursor and the type of transition metal salt in Catalyst Example 1 are changed, the molar amount of the N-heterocyclic carbene ligand precursor remains unchanged, the molar amount of the transition metal salt remains unchanged, and the rest is the same as Catalyst Example 1; the N-heterocyclic carbene complex catalyst obtained thereby replaces the catalyst used in Example 1-1 (the N-heterocyclic carbene complex catalyst prepared in Catalyst Example 1), and the rest is the same as Example 1-1.

[0090] The product yield was tested and the results are shown in Table 1 below.

[0091] Table 1. Effect of the composition of N-heterocyclic carbene complex catalyst on product yield

[0092]

[0093]

[0094] Example 2 series: Compared with Example 1-1, the reaction temperature of the pipeline reactor was changed, and the rest was the same as Example 1-1, thereby obtaining Examples 2-1 to 2-11. The product yield was tested, and the results are shown in Table 2 below.

[0095] Table 2. Effect of reaction temperature on product yield

[0096]

[0097]

[0098] Example 3 series: Compared with Example 1-1, the length of the pipeline reactor is changed, thereby changing the residence time of the reaction accordingly, and the rest is the same as Example 1-1, thereby obtaining Examples 3-1 to 3-5. The product yield is tested, and the results are described in Table 3 below.

[0099] Table 3. Effect of reaction residence time on product yield

[0100]

[0101] Example 4 series: Compared with Example 1-1, the back pressure valve after the pipeline reactor is adjusted to change the reaction pressure, and the rest is the same as Example 1-1, thereby obtaining Example 4-1 to Example 4-4. The product yield is tested, and the results are described in Table 4 below.

[0102] Table 4. Effect of reaction pressure on product yield

[0103]

[0104] Example 5 series: relative to Example 1-1, the flow rate of trimethoxysilane and allyl glycidyl ether materials was changed, and the tube length of the pipeline reactor was adjusted accordingly to ensure that the residence time of the reaction remained unchanged. The rest was the same as Example 1-1, thereby obtaining the corresponding Examples 5-1 to 5-2, and the product yield was tested. The results are described in Table 5 below.

[0105] Table 5. Effect of material flow rate ratio on product yield

[0106]

[0107] In Example 6 series, compared with Example 1-1, the reaction raw materials and reaction temperature were changed, and the reaction time remained unchanged; the remaining operations were the same as in Example 1-1, to obtain Example 6 series. The process parameters and reaction results were compared with those of Example 1-1 as shown in Table 6 below.

[0108] Table 6

[0109]

[0110]

[0111] Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. N-heterocyclic carbene complex catalyst, characterized in that: The invention comprises a ligand and an active component, wherein the ligand is an N-heterocyclic carbene ligand, and the active component is a transition metal; the molar ratio of the N-heterocyclic carbene ligand to the transition metal is 1:

1.

2. The N-heterocyclic carbene complex catalyst according to claim 1, characterized in that: The precursor corresponding to the N-heterocyclic carbene ligand is any one of the following:

3. The N-heterocyclic carbene complex catalyst according to claim 1 or 2, characterized in that: The transition metal is at least any one of the following: manganese, iron, cobalt, nickel, copper, and zinc.

4. A method for preparing an N-heterocyclic carbene complex catalyst, characterized in that The following steps are involved: Under the protection of inert gas, a transition metal salt, an N-heterocyclic carbene ligand precursor and a solvent are added to a reaction container; the reaction is carried out under the protection of inert gas at a reaction temperature of 80±10° C. for a reaction time of 1±0.2 h, and the reaction product is post-treated to obtain an N-heterocyclic carbene complex catalyst; The molar ratio of the metal in the transition metal salt to the N-heterocyclic carbene ligand precursor obtained in step 1) is 1:

1.

5. The method for preparing the N-heterocyclic carbene complex catalyst according to claim 4, characterized in that: The transition metal salt is a metal hydrochloride; the metal hydrochloride is at least one of chloride salts of manganese, iron, cobalt, nickel, copper and zinc.

6. The method for preparing the N-heterocyclic carbene complex catalyst according to claim 5, characterized in that The N-heterocyclic carbene ligand precursor is any of the following: 1-(2-pyridylmethyl)imidazole, 1,3-bis(2-pyridylmethyl)imidazole chloride, 1-(2-pyridylmethyl)-3-methylimidazole iodide, 1,1′-dimethyl-3,3′-methylenediimidazole dibromide, 1,1′-diisopropyl-3,3′-methylenediimidazole dibromide, 1,1′-methylenebis(3-(pyridin-2-yl)-1H-imidazolium) dihexafluorophosphate.

7. The method for preparing the N-heterocyclic carbene complex catalyst according to any one of claims 4 to 6, characterized in that: The solvent is toluene.

8. A method for continuously synthesizing a silane coupling agent in a pipeline, characterized in that: The invention adopts N-heterocyclic carbene complex catalyst, takes hydrogen-containing silane and unsaturated hydrocarbon as raw materials, and carries out homogeneous hydrosilylation reaction in a pipeline reactor to obtain a silane coupling agent.

9. The method for pipeline continuous synthesis of silane coupling agent according to claim 8, characterized in that The following steps are involved: 1) Addition: Hydrogen-containing silane and unsaturated hydrocarbon are pumped into a pipeline reactor at a mass flow rate ratio of 1 to 2:1, and reacted at a temperature of 50 to 150°C and a pressure of 1 to 3 MPa for 40 to 120 minutes. The reaction product flowing out of the pipeline reactor is a crude silane coupling agent product; 2) Purify and treat the crude silane coupling agent product to obtain a silane coupling agent.

10. The method for pipeline continuous synthesis of silane coupling agent according to claim 6, characterized in that: The hydrogen-containing silane is trimethoxysilane, triethoxysilane, trichlorosilane, or tris(trimethylsiloxy)silane; The unsaturated hydrocarbon is an olefin or an olefin derivative, the olefin is pentene or octene, and the olefin derivative is acrylamine, allyl methacrylate, allyl mercaptan, cyclohexane oxide ethylene, or allyl glycidyl ether.

Images