Cu-based catalyst for synthesis of lower alcohols and method of preparation

Abstract

The application relates to the technical field of catalyst preparation, in particular to a Cu-based catalyst for synthesizing low-carbon alcohols and a preparation method thereof.The preparation method comprises the following steps: S1, preparation of a pretreated and modified carrier; S2, preparation of a precursor: after copper salt and zinc salt are dissolved in deionized water, polyhydric alcohol, amino acid and organic phosphine compound are added, the pH value is adjusted to 8.0, and the precipitation is obtained after 1-1.5 hours of reaction, and the precursor is obtained after washing and drying; S3, preparation of the catalyst: the precursor and the modified carrier are added into deionized water, a high-temperature-resistant polymer is added for drying and grinding, a layered sulfide is added, the mixture is uniformly mixed and then is pressed into a tablet, the tablet is calcined under nitrogen, and the Cu-based catalyst for synthesizing low-carbon alcohols is obtained after reduction at 200-220 DEG C. The application provides the Cu-based catalyst for synthesizing low-carbon alcohols and the preparation method thereof, so as to solve the problem of poor stability of the catalyst in the related art and frequent replacement.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of catalyst preparation, in particular to a Cu-based catalyst for synthesizing low-carbon alcohols and a preparation method thereof. BACKGROUND

[0002] Low-carbon alcohols have high octane values, and can be combusted fully and efficiently, and can effectively reduce the emission of CO, CO2 and nitrogen oxides. After separation, low-carbon alcohols can obtain single alcohols such as ethanol, propanol and butanol. These alcohols are important chemical raw materials, and can be used to prepare various chemicals and also used as general chemical solvents.

[0003] The synthesis methods of low-carbon alcohols mainly include a catalytic conversion method of synthesis gas, a catalytic hydration method of low-carbon olefins and a coke oven gas synthesis method.

[0004] The existing catalysts have the problem of too low total alcohol and low-carbon alcohol selectivity, and it is difficult to efficiently convert raw materials into target low-carbon alcohol products. At the same time, too many by-products are produced, which leads to increased difficulty in subsequent separation and purification. In addition, some catalysts are prone to deactivation during the reaction process. For example, Cu-based catalysts may have Cu species sintering phenomenon, which affects the service life of the catalysts and requires frequent replacement of the catalysts, which is not conducive to industrial continuous production. SUMMARY

[0005] The application provides a Cu-based catalyst for synthesizing low-carbon alcohols and a preparation method thereof, so as to solve the problem of poor stability of the catalyst in the related art and the need for frequent replacement.

[0006] In a first aspect, a preparation method of a Cu-based catalyst for synthesizing low-carbon alcohols is provided, which comprises the following steps:

[0007] S1: preparation of a pretreated carrier:

[0008] The siliceous magnesium soil is mixed with deionized water, an inorganic acid solution is added dropwise to adjust the pH to 3.0, and then the mixture is ultrasonically treated for 30 min and left to stand for 0.5-1 h. After filtration and washing to neutral, the mixture is dried at 100-110 DEG C for 5-6 h to obtain a pretreated carrier;

[0009] The pretreated carrier is mixed with deionized water, and rare earth metal salt and transition metal salt are added under stirring at 50-60 DEG C for 1.5-2 h. After filtration, the mixture is dried at 100-110 DEG C for 11-12 h and then calcined at 480-500 DEG C for 2.5-3 h to obtain a modified carrier;

[0010] S2: preparation of a precursor:

[0011] The copper salt and the zinc salt are dissolved in deionized water in a Cu:Zn molar ratio of 3:1, and then polyhydric alcohol is added under stirring at 45-50 DEG C for 30 min to obtain a complex solution.

[0012] Add amino acid and organic phosphine compound to the complex solution, after stirring for 10 min, add 1 mol / L sodium carbonate solution to adjust pH to 8.0, and obtain precipitate after 1-1.5 h of reaction;

[0013] After washing the precipitate with deionized water and ethanol in sequence, vacuum dry at 55-60℃ for 9-10 h, grind to pass 100 mesh sieve, and obtain the precursor;

[0014] S3: Catalyst preparation:

[0015] After mixing the precursor with modified carrier in a mass ratio of 1:2 and adding deionized water, add high-temperature resistant polymer, stir and soak at 35-40℃ for 1.5-2 h, rotary evaporate to paste, vacuum dry at 70-80℃ for 7-8 h, and obtain dry material, the mass ratio of the high-temperature resistant polymer to the precursor is 1:(15-20);

[0016] After grinding the dry material, add layered sulfide, mix uniformly, press into shape at 20 MPa, crush to pass 50 mesh sieve, place in a tube furnace, and heat to 320-350℃ at 2℃ / min under nitrogen protection, and calcine for 3 h to obtain catalyst precursor, the mass ratio of the layered sulfide to the dry material is 1:50;

[0017] After placing the catalyst precursor in H2 / Ar mixed gas with a volume ratio of 1:4, reduce at 200-220℃ for 4 h, naturally cool to room temperature, switch to nitrogen protection, and obtain Cu-based catalyst for synthesizing low-carbon alcohol.

[0018] Preferably, in S1, the mass ratio of the siliceous magnesium soil to deionized water is 1:5, the mass ratio of the pretreated carrier to deionized water is 1:8, and the inorganic acid solution is 0.1 mol / L nitric acid solution or hydrochloric acid solution.

[0019] Preferably, in S1, the rare earth metal salt is one of lanthanum nitrate and cerium nitrate, the mass of the rare earth metal salt is 3-5 wt% of the mass of the pretreated carrier, the transition metal salt is one of manganese nitrate and zirconium nitrate, and the mass of the transition metal salt is 3-5 wt% of the mass of the pretreated carrier.

[0020] Preferably, in S2, the amount of deionized water added is 5 times the total mass of copper salt and zinc salt, and the molar ratio of polyol to copper is (0.8-1.2):2.

[0021] The copper salt is one of copper nitrate and copper acetate, and the zinc salt is one of zinc nitrate and zinc acetate.

[0022] Preferably, in the S2, the amino acid is one of sodium aspartate and sodium glutamate, the organic phosphine compound is one of aminoethyl phosphinic acid and diethyl phosphite, and the polyol is one of D-mannitol and sorbitol.

[0023] Preferably, the mass of the amino acid is 6-8% of the total mass of the copper salt and the zinc salt, and the molar ratio of P to Cu in the organic phosphine compound is 0.05:1.

[0024] Preferably, in the S3, the high-temperature-resistant polymer is one of polyimide and polyether sulfone, and the layered sulfide is one of molybdenum disulfide and tungsten disulfide.

[0025] In a second aspect, a Cu-based catalyst for synthesizing a low-carbon alcohol is provided, which is prepared by the method for preparing the Cu-based catalyst for synthesizing a low-carbon alcohol described in any of the above aspects.

[0026] The technical solutions provided in the present application have the following beneficial effects:

[0027] The present application provides a Cu-based catalyst for synthesizing a low-carbon alcohol and a preparation method thereof,

[0028] The copper salt and the zinc salt provide Cu 0 / Cu + The active center is Cu 0 Cu is responsible for activating H2 + The polyol and the amino acid are responsible for adsorbing CO, and the polyol and the amino acid improve the dispersion of Cu and Zn through complexation, ensuring uniform distribution of the active center, the P element introduced by the organic phosphine compound adjusts the electron density of Cu, enhances the non-dissociative adsorption capacity of CO, promotes the CO insertion reaction, and thus improves the total alcohol selectivity and C 2+ alcohol ratio;

[0029] The rare earth metal element and the carrier surface hydroxyl form a stable coordination structure, which can effectively inhibit the sintering of the carrier during the reaction; the transition metal element enhances the interaction between the carrier and the active component through electron transfer, and reduces the migration of Cu species. At the same time, the high-temperature-resistant polymer acts as a binder and a dispersant, and its rigid structure can physically block the agglomeration of Cu particles, and the interlayer confinement effect of the layered sulfide (such as molybdenum disulfide) further limits the growth of Cu particles, thereby improving the stability of the catalyst. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0031] Figure 1 The flow chart of the preparation method of the Cu-based catalyst for synthesizing low-carbon alcohol provided in the present application is shown in the following. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0033] Reference is made to Figure 1 The present application provides a Cu-based catalyst for synthesizing low-carbon alcohol and a preparation method thereof.

[0034] Embodiment 1

[0035] The preparation method of the Cu-based catalyst for synthesizing low-carbon alcohol provided in the present embodiment includes the following steps:

[0036] S1: Pretreatment and preparation of modified carrier:

[0037] After 30 g of attapulgite was mixed with 150 g of deionized water, 0.1 mol / L nitric acid solution was added dropwise to adjust the pH to 3.0, and then ultrasonic treatment was performed for 30 min, followed by standing for 1 h. After filtration and washing to neutral, drying was performed at 110°C for 6 h to obtain a pretreated carrier;

[0038] After 20 g of the pretreated carrier was mixed with 160 g of deionized water, 0.8 g of lanthanum nitrate and 1 g of manganese nitrate were added under stirring, and then stirring was performed at 60°C for 2 h. After filtration, drying was performed at 110°C for 12 h, followed by calcination at 500°C for 3 h to obtain a modified carrier;

[0039] S2: Preparation of precursor:

[0040] After 18.75 g of copper nitrate [Cu(NO3)2•3H2O] and 4.41 g of zinc nitrate [Zn(NO3)2•6H2O] were dissolved in 115.8 mL of deionized water, 5.31 g of D-mannitol was added under stirring, and then reaction was performed at 50°C for 30 min to obtain a complex solution;

[0041] After 1.39 g of sodium aspartate and 0.37 g of aminoethyl phosphinic acid were added to the complex solution, stirring was performed for 10 min, and then 1 mol / L sodium carbonate solution was added dropwise to adjust the pH to 8.0. After reaction for 1 h, a precipitate was obtained;

[0042] The precipitate was washed with deionized water and ethanol in turn, vacuum dried at 60°C for 10h, ground to pass through a 100 mesh sieve, to obtain a precursor;

[0043] S3: Catalyst preparation:

[0044] After mixing 10g of the precursor with 20g of the modified carrier and adding 60g of deionized water, 0.67g of polyether sulfone was added, and the mixture was stirred and immersed at 40°C for 2h, rotary evaporated to a paste, and then vacuum dried at 80°C for 8h to obtain a dry material;

[0045] After grinding the dry material, 0.61g of molybdenum disulfide was added, and the mixture was uniformly mixed and pressed into a tablet at 20MPa, crushed to pass through a 50 mesh sieve, and placed in a tube furnace, and heated to 350°C at 2°C / min under nitrogen protection, and calcined for 3h to obtain a catalyst precursor;

[0046] The catalyst precursor was placed in a mixed gas of H2 / Ar with a volume ratio of 1:4, and reduced at 220°C for 4h, and then naturally cooled to room temperature, and switched to nitrogen protection to obtain a Cu-based catalyst for synthesizing low-carbon alcohols.

[0047] Example 2

[0048] The preparation method of the Cu-based catalyst for synthesizing low-carbon alcohols provided in this embodiment includes the following steps:

[0049] S1: Pretreatment and preparation of modified carrier:

[0050] After mixing 30g of siliceous magnesium soil with 150g of deionized water, the pH was adjusted to 3.0 by adding a 0.1mol / L hydrochloric acid solution dropwise, and the mixture was ultrasonically treated for 30min, then stood for 1h, filtered and washed to neutral, and then dried at 100°C for 6h to obtain a pretreated carrier;

[0051] After mixing 20g of the pretreated carrier with deionized water, 1g of cerium nitrate and 0.6g of zirconium nitrate were added under stirring, and the mixture was stirred at 50°C for 2h, then filtered, dried at 100°C for 12h, and then calcined at 480°C for 3h to obtain a modified carrier;

[0052] S2: Preparation of precursor:

[0053] After dissolving 17.25g of copper acetate [Cu(CH3COO)2•H2O] and 4.32g of zinc acetate [Zn(CH3COO)2•2H2O] in 107.85mL of deionized water, 7.84g of sorbitol was added under stirring, and the mixture was reacted at 45°C for 30min to obtain a complex solution;

[0054] To the complex solution, 1.72 g of sodium glutamate and 1.04 g of diethyl phosphite were added, and after stirring for 10 min, 1 mol / L sodium carbonate solution was added dropwise to adjust the pH to 8.0. After 1 h of reaction, a precipitate was obtained;

[0055] After the precipitate was washed with deionized water and ethanol in turn, it was vacuum dried at 55°C for 10 h, ground to pass through a 100-mesh sieve, and a precursor was obtained;

[0056] S3: Catalyst preparation:

[0057] After 10 g of the precursor was mixed with 20 g of the modified carrier and then added to 60 g of deionized water, 0.5 g of polyimide was added, and the mixture was stirred and immersed at 35°C for 2 h. After rotary evaporation to a paste, the mixture was vacuum dried at 70°C for 8 h to obtain a dry material;

[0058] After the dry material was ground, 0.61 g of tungsten disulfide was added, and the mixture was uniformly mixed and then pressed into a tablet at 20 MPa. After being crushed to pass through a 50-mesh sieve, the catalyst precursor was obtained by heating to 320°C at a rate of 2°C / min under nitrogen protection and calcining for 3 h.

[0059] The catalyst precursor was placed in a mixed gas of H2 / Ar with a volume ratio of 1:4, and reduced at 200°C for 4 h. After natural cooling to room temperature, the nitrogen protection was switched to obtain a Cu-based catalyst for synthesizing lower alcohols.

[0060] Example 3

[0061] The preparation method of the Cu-based catalyst for synthesizing lower alcohols provided in this example includes the following steps:

[0062] S1: Pretreatment and preparation of modified carrier:

[0063] After 30 g of siliceous magnesium earth was mixed with 150 g of deionized water, 0.1 mol / L hydrochloric acid solution was added dropwise to adjust the pH to 3.0. After ultrasonic treatment for 30 min, it was left to stand for 1 h, filtered and washed to neutral. After drying at 105°C for 6 h, a pretreated carrier was obtained.

[0064] After 20 g of the pretreated carrier was mixed with deionized water, 0.8 g of lanthanum nitrate and 0.8 g of zirconium nitrate were added under stirring. After stirring at 55°C for 2 h, the mixture was filtered, dried at 105°C for 12 h, and then calcined at 490°C for 3 h to obtain a modified carrier.

[0065] S2: Preparation of precursor:

[0066] After 19.96 g of copper acetate and 7.73 g of zinc nitrate were dissolved in 138.45 mL of deionized water, 12.34 g of D-mannitol was added under stirring. After reaction at 48°C for 30 min, a complex solution was obtained.

[0067] To the complex solution, 1.94 g of sodium aspartate and 0.96 g of aminoethyl phosphinic acid were added, and after stirring for 10 min, 1 mol / L sodium carbonate solution was added dropwise to adjust the pH to 8.0. After 1 h of reaction, a precipitate was obtained;

[0068] After washing the precipitate with deionized water and ethanol in turn, vacuum drying at 58°C for 10 h, grinding to pass through a 100 mesh sieve, a precursor was obtained;

[0069] S3: Catalyst preparation:

[0070] After mixing 10 g of the precursor with 20 g of the modified carrier and adding deionized water, 0.625 g of polyimide was added, and stirring and impregnation were carried out at 38°C for 2 h. After rotary evaporation to a paste, vacuum drying at 75°C for 8 h, a dry material was obtained;

[0071] After grinding the dry material, 0.6125 g of molybdenum disulfide was added, and after mixing uniformly, tablet molding was carried out at 20 MPa. After crushing to pass through a 50 mesh sieve, it was placed in a tube furnace, and under the protection of nitrogen, the temperature was raised to 330°C at a rate of 2°C / min, and calcination was carried out for 3 h to obtain a catalyst precursor;

[0072] The catalyst precursor was placed in a mixed gas of H2 / Ar with a volume ratio of 1:4, and reduction was carried out at 210°C for 4 h. After natural cooling to room temperature, the protection was switched to nitrogen to obtain a Cu-based catalyst for synthesizing low-carbon alcohols.

[0073] Example 4

[0074] The preparation method of the Cu-based catalyst for synthesizing low-carbon alcohols provided in this example includes the following steps:

[0075] S1: Pretreatment and preparation of modified carrier:

[0076] After mixing 30 g of siliceous magnesium soil with 150 g of deionized water, 0.1 mol / L hydrochloric acid solution was added dropwise to adjust the pH to 3.0. After ultrasonic treatment for 30 min, it was left standing for 0.5 h, filtered and washed to neutral, and dried at 110°C for 5 h to obtain a pretreated carrier;

[0077] After mixing 20 g of the pretreated carrier with deionized water, 0.6 g of cerium nitrate and 0.8 g of manganese nitrate were added under stirring, and stirring was carried out at 60°C for 1.5 h. After filtration, drying at 110°C for 11 h, and calcination at 500°C for 2.5 h, a modified carrier was obtained;

[0078] S2: Preparation of precursor:

[0079] After dissolving 11.16 g of copper acetate and 3.09 g of zinc acetate in 138.45 mL of deionized water, 10.2 g of D-mannitol was added under stirring, and reaction was carried out at 50°C for 30 min to obtain a complex solution;

[0080] 0.93g sodium glutamate and 0.23g diethyl phosphite were added into the complex solution, after stirring for 10 min, 1 mol / L sodium carbonate solution was added dropwise to adjust the pH to 8.0, and the precipitate was obtained after 1.5h reaction;

[0081] The precipitate was washed with deionized water and ethanol in turn, and then vacuum dried at 60℃ for 9h, ground to pass through a 100 mesh sieve to obtain the precursor;

[0082] S3: Catalyst preparation:

[0083] After 10g of the precursor was mixed with 20g of the modified carrier and deionized water was added, 0.625g of polyimide was added, and then the mixture was stirred and immersed at 40℃ for 1.5h. The paste was rotary evaporated and then vacuum dried at 80℃ for 7h to obtain the dried material;

[0084] The dried material was ground, 0.6125g of molybdenum disulfide was added, and then the mixture was uniformly mixed and pressed into a tablet at 20MPa. The tablet was crushed to pass through a 50 mesh sieve, and then placed in a tube furnace. The temperature was raised to 350℃ at a rate of 2℃ / min under nitrogen protection, and then calcined for 3h to obtain the catalyst precursor;

[0085] The catalyst precursor was placed in a mixed gas of H2 / Ar with a volume ratio of 1:4, and then reduced at 220℃ for 4h. After natural cooling to room temperature, the protection was switched to nitrogen to obtain the Cu-based catalyst for synthesizing low-carbon alcohols.

[0086] Comparative Example 1

[0087] The difference between this comparative example and Example 1 is that no rare earth metal salt and transition metal salt is added in S1, and no organic phosphine is added in S2.

[0088] Comparative Example 2

[0089] The difference between this comparative example and Example 1 is that no rare earth metal salt and transition metal salt is added in S1, and no layered sulfide is added in S3.

[0090] The Cu-based catalyst for synthesizing low-carbon alcohols (hereinafter referred to as "catalyst") prepared in the above examples was tested.

[0091] A fixed bed reactor was used, 1g of the catalyst was packed in the middle of the reaction tank, and synthesis gas was used as the raw material (H2 / CO / CO2=60 / 30 / 10, volume ratio), the gas flow was 50mL / min, the reaction pressure was 3MPa, and the reaction temperature was 260℃. After 8h of stable reaction, the product composition was analyzed by gas chromatography, TCD detector was used to detect H2, CO and other permanent gases, and FID detector was used to detect low-carbon alcohols (C1~C5 alcohols) and hydrocarbon byproducts.

[0092] The results are shown in Table 1.

[0093] Table 1

[0094]

[0095] wherein C 2+ Alcohol refers to an alcohol containing 2 or more carbon atoms.

[0096] From Table 1, the performance of Example 1 is better. The carrier of the silicon-magnesium soil is modified by the rare earth metal salt lanthanum nitrate and the transition metal salt manganese nitrate, La 3+ enhances the CO adsorption capacity, Mn 2+ adjusts the distribution of the acid sites of the carrier to reduce the side reactions, the P element of the organic phosphine (aminoethyl phosphinic acid) forms an electron transfer effect with Cu to promote the CO insertion reaction (the key step of generating C 2+ alcohol), so the CO conversion rate and C 2+ alcohol selectivity are the highest.

[0097] In Comparative Example 1, the silicon-magnesium soil is not modified by the rare earth metal salt and the transition metal salt, the carrier cannot effectively adjust the acid sites and enhance the CO adsorption, and there is no organic phosphine in S2, which cannot promote the CO insertion reaction, so the CO conversion rate and C 2+ alcohol selectivity are greatly reduced; in Comparative Example 2, the silicon-magnesium soil is not modified by the rare earth metal salt and the transition metal salt, which affects the promotion effect of the carrier on the reaction, and the layered sulfide is not added in S3, which cannot provide more active sites and reduce the reaction activation energy, resulting in a CO conversion rate and C 2+ alcohol selectivity lower than those of Example 1 and other examples, but the performance is relatively better than that of Comparative Example 1 due to the retention of the organic phosphine and the like.

[0098] Based on the above tests, the CO content in the tail gas of the catalyst prepared in Example 1 is detected by gas chromatography (TCD detector) at 100 h, the CO conversion rate at 100 h is calculated, and the CO conversion rate decay rate at 100 h (as follows) is calculated.

[0099]

[0100] The initial CO conversion rate was 43.5%, the CO conversion rate at 100h was 39.9%, and the CO conversion rate attenuation rate at 100h was 8.3%. The catalyst prepared in Example 1 has good stability. On the one hand, the carrier modified by the rare earth metal salt and the transition metal salt forms a La-O-Cu bond with Cu, which limits the migration and agglomeration of Cu particles. On the other hand, the chelate structure formed by D-mannitol and sodium aspartate maintains high dispersion, and the layered structure of molybdenum disulfide (MoS2) physically isolates Cu particles, reducing the contact opportunities between particles, so that the CO conversion rate attenuation rate at 100h is controlled at a low level, meeting the needs of industrial continuous production.

[0101] The catalyst prepared in Example 1 was subjected to catalytic reaction at different temperatures and pressures, and the results are shown in Table 2.

[0102] Table 2

[0103]

[0104] It can be seen that when the temperature is reduced (240℃, 3MPa), the CO conversion rate decreases, and the selectivity remains good, because low temperature can inhibit the side reaction to a certain extent; after increasing the temperature (280℃, 3MPa), the CO conversion rate increases, but Cu will have sintering, which will lead to the decrease of C 2+ alcohol selectivity. After reducing the pressure (260℃, 2MPa), the CO adsorption amount decreases, the conversion rate decreases, the chain growth reaction is affected, and the selectivity decreases; high pressure (260℃, 4MPa) increases the CO conversion rate, but C 2+ alcohol selectivity decreases slightly. Therefore, under the reaction conditions of 260℃, 3MPa, the conversion rate is ensured, the side reactions and energy consumption caused by high pressure are avoided, and the balance between good activity and selectivity is maintained.

[0105] The above description is only a specific embodiment of the present application, which enables those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A method for preparing a Cu-based catalyst for the synthesis of lower alcohols, characterized in that, It comprises the following steps: S1: pretreatment and preparation of modified carrier: After mixing the siliceous magnesium soil with deionized water, the pH is adjusted to 3.0 by adding an inorganic acid solution dropwise, and then it is treated with ultrasound for 30 min and left to stand for 0.5-1 h. After filtration and washing to neutral, it is dried at 100-110°C for 5-6 h to obtain a pretreated carrier; The pretreated carrier is mixed with deionized water, and rare earth metal salt and transition metal salt are added under stirring. After stirring at 50-60°C for 1.5-2 h, it is dried at 100-110°C for 11-12 h after filtration, and then calcined at 480-500°C for 2.5-3 h to obtain a modified carrier; S2: preparation of precursor: After dissolving copper salt and zinc salt in deionized water according to a Cu:Zn molar ratio of 3:1, polyhydric alcohol is added under stirring, and the reaction is carried out at 45-50°C for 30 min to obtain a complex solution; To the complex solution, amino acid and organic phosphine compound are added, and after stirring for 10 min, 1 mol / L sodium carbonate solution is added dropwise to adjust the pH to 8.

0. After 1-1.5 h of reaction, a precipitate is obtained; After washing the precipitate with deionized water and ethanol in turn, it is vacuum dried at 55-60°C for 9-10 h, ground to pass through a 100-mesh sieve to obtain a precursor; S3: preparation of catalyst: After mixing the precursor with the modified carrier according to a mass ratio of 1:2 and adding deionized water, a high-temperature-resistant polymer is added, and then the mixture is stirred and immersed at 35-40°C for 1.5-2 h. After rotary evaporation to a paste, it is vacuum dried at 70-80°C for 7-8 h to obtain a dried material. The mass ratio of the high-temperature-resistant polymer to the precursor is 1:(15-20); After grinding the dried material, layered sulfide is added, and after mixing uniformly, it is pressed into a tablet at 20 MPa. After crushing to pass through a 50-mesh sieve, it is placed in a tube furnace, heated to 320-350°C at 2°C / min under nitrogen protection, and calcined for 3 h to obtain a catalyst precursor. The mass ratio of the layered sulfide to the dried material is 1:50; The catalyst precursor is placed in a H2 / Ar mixed gas with a volume ratio of 1:4, and reduced at 200-220°C for 4 h. After natural cooling to room temperature, the protection is switched to nitrogen to obtain a Cu-based catalyst for synthesizing low-carbon alcohols.

2. The preparation method of the Cu-based catalyst for synthesizing low-carbon alcohols according to claim 1, characterized in that: In S1, the mass ratio of siliceous magnesium soil to deionized water is 1:5, the mass ratio of the pretreated carrier to deionized water is 1:8, and the inorganic acid solution is 0.1 mol / L nitric acid solution or hydrochloric acid solution.

3. The preparation method of the Cu-based catalyst for synthesizing low-carbon alcohols according to claim 1, characterized in that: In S1, the rare earth metal salt is one of lanthanum nitrate and cerium nitrate, and the mass of the rare earth metal salt is 3-5 wt% of the mass of the pretreated carrier. The transition metal salt is one of manganese nitrate and zirconium nitrate, and the mass of the transition metal salt is 3-5 wt% of the mass of the pretreated carrier.

4. The preparation method of the Cu-based catalyst for synthesizing low-carbon alcohols according to claim 1, characterized in that: The adding amount of the deionized water is 5 times of the total mass of the copper salt and the zinc salt, and the molar ratio of the polyhydric alcohol to copper is (0.8-1.2):

2. The copper salt is one of copper nitrate and copper acetate, and the zinc salt is one of zinc nitrate and zinc acetate.

5. The preparation method of the Cu-based catalyst for synthesizing low-carbon alcohol according to claim 1, characterized in that: In the S2, the amino acid is one of sodium aspartate and sodium glutamate, the organic phosphine compound is one of aminoethyl phosphinic acid and diethyl phosphite, and the polyhydric alcohol is one of D-mannitol and sorbitol.

6. The preparation method of the Cu-based catalyst for synthesizing low-carbon alcohol according to claim 1 or 5, characterized in that: The mass of the amino acid is 6-8% of the total mass of the copper salt and the zinc salt, and the molar ratio of P in the organic phosphine compound to Cu in the copper salt is 0.05:

1.

7. The preparation method of the Cu-based catalyst for synthesizing low-carbon alcohol according to claim 1, characterized in that: In the S3, the high-temperature-resistant polymer is one of polyimide and polyether sulfone, and the layered sulfide is one of molybdenum disulfide and tungsten disulfide.

8. A Cu-based catalyst for the synthesis of lower alcohols, characterized in that, The Cu-based catalyst for synthesizing low-carbon alcohol is prepared by the preparation method according to any one of claims 1-7.

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