Hydrogenation catalyst, preparation method and application thereof, and method for preparing alpha-methylbenzyl alcohol

Abstract

The invention relates to the field of catalysts, and discloses a hydrogenation catalyst, a preparation method and application thereof, and a method for preparing alpha-methylbenzyl alcohol, the hydrogenation catalyst comprises a hydrogenation active component and a SiO2 carrier; the surface of the catalyst is modified by siloxane groups. The hydrogenation catalyst has the characteristics of high low-temperature hydrogenation activity and long service life. The hydrogenation catalyst is used in a liquid phase hydrogenation reaction and has high catalytic activity, so that a low-temperature liquid phase reaction can be better carried out, for example, the hydrogenation catalyst is used in preparation of alpha-methylbenzyl alcohol, the raw material acetophenone can obtain a high conversion rate, the alpha-methylbenzyl alcohol has high selectivity, and meanwhile, the hydrogenation catalyst is long in service life.

Description

Technical Field

[0001] The present invention relates to the field of catalysts, and in particular to a hydrogenation catalyst, a preparation method and application thereof, and a method for preparing alpha-methylbenzyl alcohol. Background Art

[0002] Acetophenone (AP) is a byproduct of the PO / SM process for preparing propylene oxide (PO). It is hydrogenated to prepare 1-phenylethanol (PhE), and then dehydrated to form styrene (SM), thereby improving the utilization rate of the raw material ethylbenzene and reducing unit consumption. The activity of acetophenone hydrogenation is higher than that of aliphatic ketones such as acetone. The main reason is that the phenyl group provides conjugated electrons, which increases the polarity of the C=O bond of acetophenone, making it easy to adsorb on the catalyst surface and easy to activate.

[0003] The selective hydrogenation of acetophenone (ACP) to α-methylbenzyl alcohol (MBA) has been studied on different metals. Common catalysts for acetophenone hydrogenation include precious metal catalysts with palladium, platinum, ruthenium, rhodium as active components, nickel-based catalysts and copper-based catalysts. Although the reaction conditions are mild, the selectivity of α-methylbenzyl alcohol is poor when using precious metal catalysts and nickel-based catalysts for acetophenone hydrogenation [Wang Youzhen, Qiao Minghua, Hu Huarong, Yan Shirun, Wang Weijiang, Fan Kangnian, Preparation and Characterization of Highly Selective Ni-Sn-B / SiO2 Amorphous Catalyst for Acetophenone Hydrogenation, Acta Chemica Sinica, Vol. 62, No. 14, 2004, 1349-1352; Sheng Xudong, Zhang Wei, Lu Mohong. Selective Hydrogenation of Acetophenone to α-Phenylethanol Catalyzed by Palladium / Mesoporous Carbon. Fine Petrochemicals, 2015, 32(2): 58-62.]. The copper-based catalyst has good low-temperature activity, strong CO bond selectivity and weak CC bond formation ability, which can improve the selectivity of phenylethanol.

[0004] Wang Bing et al. from Qingdao University of Science and Technology (Wang Bing, Master's thesis of Qingdao University of Science and Technology, 2019) studied the effect of the preparation method of Cu / SiO2 catalyst on its performance in acetophenone hydrogenation and found that the Cu / SiO2 catalyst prepared by urea method had the best performance, but they did not systematically study the effects of silicon source, additives, etc. on Cu / SiO2 catalyst. NMBertero et al. (Applied Catalysis A: General 349 (2008) 100-109) studied the effect of solvent on the hydrogenation performance of acetophenone on Cu / SiO2 catalyst and found that the activity order of AP hydrogenation corresponding to different solvents was IPA>cyclohexane>toluene>benzene. They also conducted kinetic studies and found that AP was strongly adsorbed on Cu / SiO2 catalyst and was a negative order in the reaction, while PhE was weakly adsorbed on the catalyst surface and quickly desorbed from the catalyst surface after the reaction.

[0005] Sumitomo Chemical Company of Japan has reported in patents that Cu / SiO2 is used for acetophenone hydrogenation reaction [Oku et al., Sumitomo Chemical Company. US6410806, 2002.; T.Hibi, S.Ito, Sumitomo Chemical Company. US5663458, 1997.], when the copper content is greater than 65%, the selectivity of α-methylbenzyl alcohol is higher. At the same time, the addition of alkali or alkaline earth metal can effectively prevent the occurrence of α-methylbenzyl alcohol hydrogenolysis reaction.

[0006] The catalyst for preparing α-methylbenzyl alcohol from acetophenone is a hydrogenation catalyst, and the above reports do not involve the problem of catalyst deactivation under low-temperature reaction conditions. Summary of the invention

[0007] In hydrogenation reactions, especially in liquid phase hydrogenation reactions, the activity of hydrogenation catalysts crosses, and the generation of water during the hydrogenation reaction will deactivate the hydrogenation catalysts. The purpose of the present invention is to overcome the problems of poor reaction activity and poor catalyst stability of existing hydrogenation catalysts when used, especially in liquid phase hydrogenation reactions, and to provide a new hydrogenation catalyst and its preparation method and application, as well as a method for preparing α-methylbenzyl alcohol using the hydrogenation catalyst. The hydrogenation catalyst has the advantages of high low temperature hydrogenation activity and long service life.

[0008] The first aspect of the present invention provides a hydrogenation catalyst, which includes a hydrogenation active component and a SiO2 carrier; the catalyst surface is modified with a siloxane group.

[0009] The second aspect of the present invention provides a method for preparing a hydrogenation catalyst, the preparation method comprising: modifying the surface of a SiO2 carrier loaded with a hydrogenation active component with siloxane groups to obtain a hydrogenation catalyst.

[0010] The third aspect of the present invention provides the use of the hydrogenation catalyst of the present invention and / or the hydrogenation catalyst prepared by the method for preparing the hydrogenation catalyst of the present invention in a liquid phase hydrogenation reaction.

[0011] A fourth aspect of the present invention provides a method for preparing α-methylbenzyl alcohol, comprising: in the presence of the hydrogenation catalyst of the present invention and / or the hydrogenation catalyst prepared by the method for preparing the hydrogenation catalyst of the present invention, contacting a raw material mixed liquid containing acetophenone with hydrogen to carry out a liquid phase hydrogenation reaction.

[0012] Through the above technical scheme, the beneficial effects that can be obtained by the present invention include: the hydrogenation catalyst provided by the present invention has high low-temperature liquid phase reaction catalyst activity, can reduce the possibility of dehydration side reactions during liquid phase reactions and reduce the possibility of water accumulation in the active center of the catalyst, thereby improving the stability of the catalyst during low-temperature reactions. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is the infrared spectrum of the hydroxyl group of hydrogenation catalyst CM-1 and hydrogenation catalyst SCM-1 in Example 1. DETAILED DESCRIPTION

[0014] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0015] In the present invention, to a certain extent, the stability of the hydrogenation catalyst of the present invention is positively correlated with the one-way life of the catalyst, wherein the one-way life refers to a certain active time of the catalyst when in use, which can provide a feedstock conversion rate and target product selectivity.

[0016] The first aspect of the present invention provides a hydrogenation catalyst, which includes a hydrogenation active component and a SiO2 carrier; the catalyst surface is modified with a siloxane group.

[0017] In the present invention, the surface of the hydrogenation catalyst provided by the present invention is modified with siloxane groups and has good stability.

[0018] According to a preferred embodiment of the present invention, the carrier is modified with a siloxane group. The hydrogenation catalyst of this embodiment can reduce the possibility of dehydration side reactions and the possibility of water accumulation in the active center of the catalyst, thereby improving the stability of the hydrogenation catalyst during low temperature reactions.

[0019] According to a preferred embodiment of the present invention, the siloxane group is provided by a siloxane group-containing compound. The hydrogenation catalyst of this embodiment can reduce the possibility of dehydration side reactions and reduce the possibility of water accumulation in the active center of the catalyst, thereby improving the stability of the hydrogenation catalyst during low temperature reactions.

[0020] According to a preferred embodiment of the present invention, the siloxane group is provided by a siloxane group-containing compound represented by formula (I),

[0021]

[0022] In formula (I), R1, R2, R3 and R4 are each independently an alkyl group.

[0023] In the present invention, the "alkyl group" may be a branched alkyl group or a straight-chain alkyl group, and the present invention has no particular limitation thereto.

[0024] According to a preferred embodiment of the present invention, in formula (I), R1, R2, R3 and R4 are each independently a C1-C5 alkyl group, preferably a C1-C2 alkyl group. The hydrogenation catalyst of this embodiment has better low-temperature catalytic activity and stability.

[0025] According to the present invention, R1, R2, R3 and R4 may be the same or different. Based on the availability of raw materials, R1, R2, R3 and R4 are the same.

[0026] According to a preferred embodiment of the present invention, the mass ratio of the siloxane-containing compound to the carrier is 0.05-0.3: 1. The hydrogenation catalyst of this embodiment has better low-temperature catalytic activity and stability.

[0027] In one embodiment, the hydrogenation active component includes Cu and MO x ;The MO x At least one selected from oxides of Group IIB metals, oxides of Group VIB metals, oxides of Group VIIB metals, and oxides of Group VIII metals. x The synergistic effect between them improves the catalytic performance and stability of the hydrogenation catalyst.

[0028] According to a preferred embodiment of the present invention, the MO x At least one selected from ZnO, MnO, CoO and MoO3.

[0029] According to a preferred embodiment of the present invention, the MO x It is CoO and / or MoO3.

[0030] According to a preferred embodiment of the present invention, the Cu is calculated as an element, MO is calculated as an element, x Calculated as oxide, Cu and MO x The weight ratio of is 1 to 20. The hydrogenation catalyst of this embodiment has better catalytic activity and stability.

[0031] According to a preferred embodiment of the present invention, the hydrogenation active component accounts for 50-400% by weight of the carrier, preferably 100-300% by weight.

[0032] The second aspect of the present invention provides a method for preparing a hydrogenation catalyst, the preparation method comprising: modifying the surface of a SiO2 carrier loaded with a hydrogenation active component with siloxane groups to obtain a hydrogenation catalyst.

[0033] In the present invention, the hydrogenation active component is loaded on a SiO2 carrier, and the surface of the SiO2 carrier loaded with the hydrogenation active component is modified with siloxane groups so that the silanol groups on the surface of the carrier SiO2 can be replaced by siloxane groups, thereby reducing the possibility of dehydration side reactions and the possibility of water accumulation in the active center of the catalyst, thereby improving the stability of the catalyst during low-temperature reactions.

[0034] According to a preferred embodiment of the present invention, the method for surface siloxane modification comprises: in the presence of a solvent, contacting a SiO2 carrier loaded with a hydrogenation active component with a siloxane-containing compound, heating under reflux, and then drying the solid product. The hydrogenation catalyst obtained by adopting this embodiment can reduce the possibility of dehydration side reactions and reduce the possibility of water accumulation in the active center of the catalyst, thereby improving the stability of the catalyst during low-temperature reactions.

[0035] According to the present invention, the heating temperature can be any temperature that can induce reflux, and is generally near the boiling point of the solvent or greater than the boiling point of the solvent.

[0036] According to a preferred embodiment of the present invention, the silicon-containing siloxane group compound has a structural formula shown in formula (I):

[0037]

[0038] In formula (I), R1, R2, R3 and R4 are each independently an alkyl group, preferably a C1-C5 alkyl group, and more preferably a C1-C2 alkyl group.

[0039] According to a preferred embodiment of the present invention, the carrier source is calculated as SiO2, and the mass ratio of the siloxane-containing compound to the SiO2 carrier source is 0.05-0.3: 1. The hydrogenation catalyst obtained by adopting this embodiment can well reduce the possibility of water accumulation in the active center of the catalyst, reduce the occurrence of side reactions in the hydrogenation reaction, and increase the stability of the hydrogenation catalyst.

[0040] According to a preferred embodiment of the present invention, the solvent is selected from C6-C8 benzene series, preferably at least one of benzene, toluene and xylene.

[0041] According to a preferred embodiment of the present invention, the carrier source is calculated as SiO2, and the mass ratio of the solvent to the SiO2 carrier source is 5-100:1.

[0042] According to a preferred embodiment of the present invention, the heating reflux conditions include: temperature 80-140° C., time 2-24 h.

[0043] According to the present invention, after heating and refluxing, solid-liquid separation can be performed by filtering to obtain a solid product. After solid-liquid separation, the filter cake can be washed with a corresponding solvent to obtain a solid product.

[0044] According to the present invention, the drying conditions include: drying temperature of 60-150° C., and drying time of 5-20 hours.

[0045] According to the present invention, when the solid product is dried, care should be taken to isolate oxygen, that is, the process should be carried out under anaerobic conditions, such as vacuum drying or drying under nitrogen protection.

[0046] According to the present invention, as long as the purpose of the present invention can be achieved, the method for obtaining the SiO2 carrier loaded with hydrogenation active components is not particularly limited. According to a preferred embodiment of the present invention, the method for obtaining the SiO2 carrier loaded with hydrogenation active components comprises: kneading a hydrogenation active source, a SiO2 carrier source, an optional extrusion aid and optional water, optionally forming, and then drying, roasting and reducing;

[0047] According to a preferred embodiment of the present invention, the hydrogenation active source includes a copper salt precursor and a metal M precursor; M is selected from at least one of Group IIB metals, Group VIB metals, Group VIIB metals and Group VIII metals. x Modification of Cu / SiO2 catalyst to obtain Cu-MO x / SiO2, which can improve the activity of the catalyst and enable it to react at a lower temperature. At the same time, the modification of the siloxane group can replace the silanol groups on the surface of the carrier SiO2 with siloxane groups, reducing the possibility of dehydration side reactions and the possibility of water accumulation in the active center of the catalyst, thereby improving the stability of the catalyst during low-temperature reactions.

[0048] According to a particularly preferred embodiment of the present invention, the M is selected from at least one of Zn, Mn, Co and Mo, preferably Co and / or Mo. By adopting the above embodiment, the obtained hydrogenation catalyst has better low-temperature catalytic activity and stability.

[0049] According to a preferred embodiment of the present invention, the hydrogenation active component source is calculated as the hydrogenation catalytic component, and the SiO2 carrier source is calculated as SiO2, and the hydrogenation active component source accounts for 50-400% by weight of the weight of the SiO2 carrier source. By adopting the above embodiment, the obtained hydrogenation catalyst has better low-temperature catalytic activity and stability.

[0050] In the present invention, the kneading method and device can be any method and device in the art, for example, kneading is carried out in a kneader, and the kneading time can be selected according to needs, for example, kneading for 10-60 minutes.

[0051] According to the present invention, "optionally" means using or not using the feature as needed; for example, optional molding means performing molding or not performing molding as needed, preferably performing molding. Specifically, the kneaded product can be extruded into thin strips of a certain diameter in an extruder, for example, the kneaded product is extruded into thin strips in a twin-screw extruder, and the diameter of the thin strips can be 1.0-3.0 mm and the length can be 2-15 mm.

[0052] According to a preferred embodiment of the present invention, the copper salt precursor is selected from at least one of copper nitrate, copper hydrochloride and basic carbonate.

[0053] According to a preferred embodiment of the present invention, the precursor of the metal M is selected from at least one of nitrates, hydrochlorides, metal acid salts and basic carbonates of the metal M.

[0054] According to a preferred embodiment of the present invention, the SiO2 carrier source is selected from silicon dioxide powder and / or silica sol.

[0055] According to a preferred embodiment of the present invention, the extrusion aid is selected from at least one of sesbania powder, citric acid and graphite powder.

[0056] According to a preferred embodiment of the present invention, the copper salt precursor is calculated as Cu element, and the precursor of metal M is calculated as M oxide, and the weight ratio of the copper salt precursor to the precursor of metal M is 1-20.

[0057] According to a preferred embodiment of the present invention, the amount of the extrusion aid is 1%-20% of the mass of the copper salt precursor.

[0058] According to a preferred embodiment of the present invention, the amount of water used is 5-150% of the mass of the copper salt precursor.

[0059] According to a preferred embodiment of the present invention, when obtaining a SiO2 carrier loaded with hydrogenation active components, the drying conditions include: a drying temperature of 60-150°C and a drying time of 5-20h.

[0060] According to a preferred embodiment of the present invention, the calcination conditions include: the calcination temperature is 300-500°C.

[0061] According to a preferred embodiment of the present invention, the calcination conditions include: calcination time 2-10h.

[0062] According to a preferred embodiment of the present invention, the reduction conditions include: reduction with a reducing gas, preferably the reducing gas is hydrogen.

[0063] According to a preferred embodiment of the present invention, the reduction conditions include: the pressure of the reducing gas is 0.1-1 MPa.

[0064] According to a preferred embodiment of the present invention, the reduction conditions include: a gas hourly space velocity of 200-1000h -1 a.

[0065] According to a preferred embodiment of the present invention, the reduction conditions include: the reduction temperature is 160-270°C.

[0066] According to a preferred embodiment of the present invention, the reduction conditions include: the reduction time is 2-10 hours.

[0067] The third aspect of the present invention provides the use of the hydrogenation catalyst of the present invention and / or the hydrogenation catalyst prepared by the method for preparing the hydrogenation catalyst of the present invention in a liquid phase hydrogenation reaction.

[0068] In the present invention, the hydrogenation catalyst of the present invention is used in a liquid phase hydrogenation reaction. The hydrogenation catalyst has high catalytic activity, so that the low-temperature liquid phase reaction can be carried out better, and the possibility of dehydration side reactions and the possibility of water accumulation in the active center of the catalyst can be reduced, thereby improving the stability of the catalyst during low-temperature reactions.

[0069] According to a preferred embodiment of the present invention, the hydrogenation catalyst is used in the liquid phase hydrogenation of aryl alkyl ketones. With this embodiment, the aryl alkyl ketones have a high conversion rate and target product selectivity, and the hydrogenation catalyst can operate more stably in the liquid phase hydrogenation of aryl alkyl ketones.

[0070] A fourth aspect of the present invention provides a method for preparing α-methylbenzyl alcohol, comprising: in the presence of the hydrogenation catalyst of the present invention and / or the hydrogenation catalyst prepared by the method for preparing the hydrogenation catalyst of the present invention, contacting a raw material mixed liquid containing acetophenone with hydrogen to carry out a liquid phase hydrogenation reaction.

[0071] In the present invention, the hydrogenation catalyst of the present invention is used to prepare α-methylbenzyl alcohol, wherein the raw material acetophenone obtains a high conversion rate, the target product α-methylbenzyl alcohol has a high selectivity, and the liquid phase hydrogenation reaction is stably operated for 3000 hours, and the selectivity of the raw material acetophenone and α-methylbenzyl alcohol does not decrease significantly.

[0072] According to the present invention, the raw material mixture containing acetophenone refers to a raw material mixture of acetophenone and a solvent. The present invention has no particular limitation on the type of the solvent. For example, the solvent in the raw material mixture may be an alkanol; wherein the alkanol is preferably a C1-C5 alkyl alcohol, further methanol and / or ethanol.

[0073] According to the present invention, the concentration of acetophenone in the raw material mixed solution containing acetophenone is not particularly limited, for example, the raw material mixed solution has a concentration of 10-50 wt % of acetophenone.

[0074] According to the present invention, for the conditions of the hydrogenation reaction, those skilled in the art can select conditions that are conducive to the hydrogenation reaction as needed. In some embodiments, the conditions of the hydrogenation reaction include: the mass space velocity of acetophenone in the raw material mixture is 0.1-1.0h -1 , preferably 0.3-0.6h -1 , including but not limited to 0.35h -1 、0.4h -1 , 0.45h -1 , 0.5h -1 、0.55h -1 wait.

[0075] According to the present invention, in some embodiments, the conditions of the hydrogenation reaction include: the hydrogen pressure is 1.0-5MPa, preferably 1.5-4MPa, including but not limited to 2.0MPa, 2.5MPa, 3.0MPa, 3.5MPa, etc.

[0076] According to the present invention, in some embodiments, the conditions of the hydrogenation reaction include: a feed molar ratio of hydrogen to acetophenone of 1.0-20, preferably 1.2-15, including but not limited to 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, etc.

[0077] According to the present invention, in some embodiments, the reaction temperature is 60-120°C, preferably 65-90°C, including but not limited to 70°C, 75°C, 80°C, 85°C, etc.

[0078] The present invention will be described in detail below through examples.

[0079] Example 1

[0080] Preparation of hydrogenation catalyst:

[0081] 103.6 g of basic copper carbonate, 13.7 g of ammonium molybdate, and 30.0 g of SiO2 powder were placed in a kneader, 10 g of citric acid and 5 g of sesbania powder were added, and 100 g of water was added. After kneading for 30 min, the mixture was extruded into thin strips with a diameter of 2 mm in an extruder; dried at 120 ° C for 10 h, and calcined at 350 ° C for 4 h to obtain the catalyst precursor CMO-1;

[0082] CMO-1 was loaded into a fixed bed reactor and reduced with hydrogen at a hydrogen pressure of 0.5 MPa and a hydrogen volume space velocity of 500 h -1 , the reduction temperature was 230°C, the reduction time was 6 hours, and the obtained catalyst was CM-1;

[0083] 20 g of CM-1 catalyst was placed in a three-necked flask, 200 mL of toluene and 5 g of tetramethyl silicate were added, refluxed at 110°C for 4 hours, filtered, washed with toluene 5 times, 200 mL of toluene each time, and then vacuum dried at 60°C for 12 hours. The obtained hydrogenation catalyst was recorded as SCM-1, and its weight parts were 57.5 parts of Cu, 9.6 parts of MoO3, 28.8 parts of SiO2, and 4.0 parts of silicate.

[0084] The IR spectra of the hydroxyl groups of hydrogenation catalyst CM-1 and hydrogenation catalyst SCM-1 are shown in Figure 1 As shown, through Figure 1 It can be seen that the concentration of silanol groups on the surface of the hydrogenation catalyst SCM-1 is significantly lower than that of the hydrogenation catalyst CM-1.

[0085] Example 2

[0086] Preparation of hydrogenation catalyst:

[0087] 151.2 g of copper nitrate trihydrate, 18.3 g of zinc nitrate hexahydrate, 25 g of 40% silica sol AN-40, and 44 g of SiO2 powder were placed in a kneader, 20 g of citric acid and 10 g of sesbania powder were added, and 50 g of water was added. After kneading for 30 min, the mixture was extruded into thin strips with a diameter of 2 mm in an extruder, dried at 80°C for 20 h, and calcined at 500°C for 2 h to obtain a catalyst precursor CMO-2.

[0088] CMO-2 was loaded into a fixed bed reactor and reduced with hydrogen at a hydrogen pressure of 0.8 MPa and a hydrogen volume space velocity of 800 h -1 The reduction temperature was 180°C and the reduction time was 9 hours, and the obtained catalyst was CM-2.

[0089] 20 g of CM-2 catalyst was placed in a three-necked flask, 400 mL of benzene and 10 g of tetraethyl silicate were added, refluxed at 100°C for 10 hours, filtered, washed with benzene 5 times, 200 mL of benzene each time, and then dried at 100°C in a nitrogen atmosphere for 12 hours. The obtained hydrogenation catalyst was recorded as SCM-2. Its weight parts were 37.8 parts of Cu, 4.7 parts of ZnO, 50.9 parts of SiO2, and 6.6 parts of silicate.

[0090] Example 3

[0091] Preparation of hydrogenation catalyst:

[0092] 120.9 g of basic copper carbonate, 29.4 g of cobalt nitrate hexahydrate, 30 g of 40% silica sol AN-40, and 10.5 g of SiO2 powder were placed in a kneader, 5 g of citric acid and 3 g of sesbania powder were added, and 20 g of water was added. After kneading for 20 min, the mixture was extruded into thin strips with a diameter of 2 mm in an extruder, dried at 120° C. for 10 h, and calcined at 300° C. for 4 h to obtain a catalyst precursor CMO-3.

[0093] CMO-3 was loaded into a fixed bed reactor and reduced with hydrogen at a hydrogen pressure of 0.3 MPa and a hydrogen volume space velocity of 800 h -1 , the reduction temperature is 200°C, the reduction time is 5 hours, and the obtained catalyst is CM-3;

[0094] 20 g of CM-1 catalyst was placed in a three-necked flask, and 200 mL of toluene and 5 g of tetramethyl silicate were added, and refluxed at 110°C for 4 hours. After filtering, it was washed with toluene 5 times, each time with 200 mL of toluene, and then vacuum dried at 60°C for 12 hours. The obtained hydrogenation catalyst was recorded as SCM-3, and its weight parts were 68.1 parts of Cu, 7.3 parts of CoO, 21.9 parts of SiO2, and 2.6 parts of silicate.

[0095] Example 4

[0096] Preparation of hydrogenation catalyst:

[0097] 120.9 g of basic copper carbonate, 37.8 g of 50% manganese nitrate aqueous solution, 30 g of 40% silica sol AN-40, and 10.5 g of SiO2 powder were placed in a kneader, 5 g of citric acid and 3 g of sesbania powder were added, and 20 g of water was added. After kneading for 20 min, the mixture was extruded into thin strips with a diameter of 2 mm in an extruder, dried at 120° C. for 10 h, and calcined at 300° C. for 4 h to obtain a catalyst precursor CMO-4;

[0098] CMO-4 was loaded into a fixed bed reactor and reduced with hydrogen at a hydrogen pressure of 0.3 MPa and a hydrogen volume space velocity of 800 h -1, the reduction temperature is 200°C, the reduction time is 5 hours, and the obtained catalyst is CM-4;

[0099] 20 g of CM-4 catalyst was placed in a three-necked flask, 200 mL of toluene and 5 g of tetramethyl silicate were added, refluxed at 110°C for 4 hours, filtered, washed with toluene 5 times, 200 mL of toluene each time, and then vacuum dried at 60°C for 12 hours. The obtained hydrogenation catalyst was recorded as SCM-4. Its weight parts were 68.3 parts of Cu, 7.3 parts of MnO, 22.0 parts of SiO2, and 2.4 parts of silicate.

[0100] Example 5

[0101] The method of Example 1 was followed, except that the vacuum drying at 60° C. for 12 h was replaced by drying at 60° C. in air atmosphere for 12 h. The obtained catalyst was designated as SCM-5.

[0102] Example 6

[0103] The method of Example 1 was followed, except that 5 g of tetramethyl silicate was replaced by 5 g of tetra-n-butyl silicate. The resulting catalyst was designated as SCM-6.

[0104] Example 7

[0105] 20 g of SCM-1 catalyst (length 3-6 mm) was loaded into a 12 mm stainless steel reactor and reacted at 65 °C with a hydrogen pressure of 2.0 MPa. The acetophenone raw material was a 30% acetophenone ethanol solution and the acetophenone space velocity was 0.3 h -1 The molar ratio of hydrogen to acetophenone was 2.0. Samples were taken after 24 hours of reaction, and the conversion rate of acetophenone was 93.5%, the selectivity of α-methylbenzyl alcohol was 99.8%, and the selectivity of ethylbenzene was 0.2%.

[0106] Example 8

[0107] Catalyst SCM-2 was evaluated in the same manner as in Example 7, and the conversion rate of acetophenone obtained was 78.3%, the selectivity of α-methylbenzyl alcohol was 98.8%, and the selectivity of ethylbenzene was 1.2%.

[0108] Example 9

[0109] Catalyst SCM-3 was evaluated in the same manner as in Example 7, and the conversion rate of acetophenone obtained was 89.3%, the selectivity of α-methylbenzyl alcohol was 99.3%, and the selectivity of ethylbenzene was 0.7%.

[0110] Example 10

[0111] Catalyst SCM-4 was evaluated in the same manner as in Example 7, and the conversion rate of acetophenone obtained was 62.8%, the selectivity of α-methylbenzyl alcohol was 99.7%, and the selectivity of ethylbenzene was 0.3%.

[0112] Embodiment 11

[0113] Catalyst SCM-5 was evaluated in the same manner as in Example 7, and the conversion rate of acetophenone obtained was 75.6%, the selectivity of α-methylbenzyl alcohol was 99.2%, and the selectivity of ethylbenzene was 0.8%.

[0114] Example 12

[0115] Catalyst SCM-6 was evaluated in the same manner as in Example 7, and the conversion rate of acetophenone obtained was 53.5%, the selectivity of α-methylbenzyl alcohol was 98.3%, and the selectivity of ethylbenzene was 1.7%.

[0116] Examples 13-16

[0117] Catalyst SCM-1 was evaluated in the same manner as in Example 7 except that the reaction conditions were changed. The results are shown in Table 1.

[0118] Table 1

[0119]

[0120] Embodiment 17

[0121] The life of the catalyst SCM-1 was evaluated in the same manner as in Example 7. The results are shown in Table 2.

[0122] Table 2

[0123]

[0124]

[0125] Comparative Example 1

[0126] The life of catalyst CM-1 was evaluated in the same manner as in Example 7. The results are shown in Table 3.

[0127] Table 3

[0128] Reaction time (h) ACP conversion rate (%) MBA selectivity (%) 500 85.6 99.3 1000 78.3 99.5 1500 70.4 99.0 2000 65.4 98.9 2500 55.4 98.8 3000 45.6 99.4

[0129] Comparative Example 2

[0130] Preparation of hydrogenation catalyst:

[0131] The method of Example 3 was followed, except that 48.1 g of magnesium nitrate hexahydrate was used to replace 29.4 g of cobalt nitrate hexahydrate, to obtain hydrogenation catalyst cCM-2.

[0132] The hydrogenation catalyst cCM-2 was evaluated in the same manner as in Example 7, and the conversion of acetophenone was 35.6%, the selectivity of 1-phenylethanol was 97.2%, and the selectivity of ethylbenzene was 2.8%.

[0133] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A hydrogenation catalyst, characterized in that The hydrogenation catalyst comprises a hydrogenation active component and a SiO2 carrier; the surface of the catalyst is modified with siloxane groups.

2. The hydrogenation catalyst according to claim 1, wherein The siloxane group is provided by a siloxane group-containing compound; Preferably, the siloxane group is provided by a siloxane group-containing compound represented by formula (I), In formula (I), R1, R2, R3 and R4 are each independently an alkyl group, preferably a C1-C5 alkyl group, and more preferably a C1-C2 alkyl group; and / or The mass ratio of the siloxane-containing compound to the carrier is 0.05-0.3:

1.

3. The hydrogenation catalyst according to claim 1 or 2, wherein The hydrogenation active component includes Cu and MO x ;The MO x At least one selected from the group consisting of oxides of Group IIB metals, oxides of Group VIB metals, oxides of Group VIIIB metals, and oxides of Group VIII metals; Preferably, the MO x At least one selected from ZnO, MnO, CoO and MoO3, preferably CoO and / or MoO3; and / or The Cu is calculated as an element, MO x Calculated as oxide, Cu and MO x The weight ratio is 1-20.

4. The hydrogenation catalyst according to any one of claims 1 to 3, wherein The hydrogenation active component accounts for 50-400 wt %, preferably 100-300 wt %, of the weight of the carrier.

5. A method for preparing a hydrogenation catalyst, characterized in that: The preparation method comprises: modifying the surface of a SiO2 carrier loaded with hydrogenation active components with siloxane groups to obtain a hydrogenation catalyst.

6. The preparation method according to claim 5, wherein: The method for modifying the surface with siloxane groups comprises: contacting a SiO2 carrier loaded with a hydrogenation active component with a compound containing siloxane groups in the presence of a solvent, heating under reflux, and then drying the solid product; Preferably, the siloxane-containing compound has the structural formula shown in formula (I), In formula (I), R1, R2, R3 and R4 are each independently an alkyl group, preferably a C1-C5 alkyl group, and more preferably a C1-C2 alkyl group; and / or The carrier source is calculated as SiO2, and the mass ratio of the siloxane-containing compound to the SiO2 carrier source is 0.05-0.3:1; and / or The solvent is selected from C6-C8 benzene series, preferably at least one of benzene, toluene and xylene; and / or The carrier source is calculated as SiO2, and the mass ratio of the solvent to the SiO2 carrier source is 5-100:1; and / or The heating reflux conditions include: temperature of 80-140°C; and / or time of 2-24h; and / or The drying conditions include: a drying temperature of 60-150° C. and / or a drying time of 5-20 h, preferably under anaerobic conditions.

7. The preparation method according to claim 5 or 6, wherein: The method for obtaining a SiO2 carrier loaded with a hydrogenation active component comprises: kneading a hydrogenation active source, a SiO2 carrier source, an optional extrusion aid and optional water, optionally forming, and then drying, calcining and reducing; Preferably, the hydrogenation active source comprises a copper salt precursor and a precursor of a metal M, wherein M is selected from at least one of a Group IIB metal, a Group VIB metal, a Group VIIB metal and a Group VIII metal; More preferably, the copper salt precursor is selected from at least one of copper nitrate, copper hydrochloride and basic carbonate; and / or The precursor of the metal M is selected from at least one of nitrates, hydrochlorides, metal acid salts and basic carbonates of the metal M; and / or The SiO2 carrier source is selected from silicon dioxide powder and / or silica sol; and / or The extrusion aid is selected from at least one of sesbania powder, citric acid, and graphite powder; and / or The amount of the extrusion aid is 1-20% of the mass of the copper salt precursor; and / or The amount of water used is 5%-150% of the mass of the copper salt precursor; and / or The drying conditions include: drying temperature of 60-150°C and / or drying time of 5-20h; and / or The calcination conditions include: a calcination temperature of 300-500° C. and / or a calcination time of 2-10 h; and / or The reduction conditions include: reducing with reducing gas, preferably hydrogen, and / or reducing gas pressure of 0.1-1 MPa, and / or gas hourly space velocity of 200-1000 h -1 a, and / or the reduction temperature is 160-270°C, and / or the reduction time is 2-10h.

8. Use of the hydrogenation catalyst according to any one of claims 1 to 4 and / or the hydrogenation catalyst prepared by the preparation method according to any one of claims 5 to 7 in a liquid phase hydrogenation reaction; Preferably, the hydrogenation catalyst is used in liquid phase hydrogenation of aryl alkyl ketones.

9. A method for preparing α-methylbenzyl alcohol, characterized in that: The method comprises: in the presence of the hydrogenation catalyst described in any one of claims 1 to 4 and / or the hydrogenation catalyst prepared by any one of the preparation methods of claims 5 to 7, a raw material mixed liquid containing acetophenone is contacted with hydrogen to carry out a liquid phase hydrogenation reaction.

10. The method according to claim 9, wherein: The solvent in the raw material mixture is an alkanol, preferably a C1-C5 alkyl alcohol, more preferably methanol and / or ethanol; and / or The conditions of the hydrogenation reaction include: The mass space velocity of acetophenone in the raw material mixture is 0.1-1h -1 , preferably 0.3-0.6h -1 ; and / or The hydrogen pressure is 1.0-5 MPa, preferably 1.5-4 MPa; and / or The feed molar ratio of hydrogen to acetophenone is 1.0-20, preferably 1.2-15; and / or The reaction temperature is 60-120°C, preferably 65-90°C.

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