Preparation method of tetrahydrofurfuryl alcohol ether

Abstract

The invention provides a preparation method of tetrahydrofurfuryl alcohol diethyl ether. The method comprises the following steps: by taking a reaction kettle as a reactor and taking furfural and ethanol as reaction raw materials, under the action of a specific catalyst, firstly enabling the reaction raw materials to generate furfuryl ether under a first reaction condition, and then enabling the furfuryl ether to generate tetrahydrofurfuryl alcohol ether under a second reaction condition, the catalyst comprises a carrier ZSM-5, and a noble metal M and a metal component Ni which are loaded on the carrier ZSM-5, and the noble metal M is selected from one of Pd, Pt, Au, Ir and Ru. According to the method provided by the invention, the reaction of the two stages is controlled to be carried out under two different reaction conditions, the tetrahydrofurfuryl alcohol diethyl ether is prepared from furfural through a one-step method, and the adopted catalyst has the advantages of good catalytic activity and good catalyst stability.

Description

Technical Field

[0001] The invention belongs to the technical field of fine chemicals, and particularly relates to a method for preparing tetrahydrofurfuryl alcohol ethyl ether. Background Art

[0002] Ethyl tetrahydrofurfuryl ether (ETE) can not only be used as an excellent solvent, but more importantly, it can be used as a structural regulator for the synthesis of high 1, 2-structure polybutadiene rubber from diene monomers, such as BR, SSBR, SBS and other high 1, 2-structure regulators. Its regulating ability is stronger than that of Lewis bases such as fatty ethers, THF, and tertiary amines.

[0003] Dai Liping et al. (Sichuan Chemical Industry, 2010, 13(3): 9-12) used a conventional ETE synthesis method to synthesize tetrahydrofurfuryl ether (ETE) from ethyl bromide and tetrahydrofurfuryl alcohol (THFA) in the presence of metallic Na, with a yield of 75%. However, this method is not only costly, but also the presence of metallic Na in the reaction system makes post-processing complicated and harmful to the environment and human health. The second synthesis method is to prepare ETE by hydrogenation of furfuryl ether. Cao et al. (Catalysis Communications, 2015, 58: 76-79) reported that the yield of preparing tetrahydrofurfuryl ether by hydrogenation of furfuryl ether under Raney nickel catalysis exceeded 99%.

[0004] The route of etherification of raw material furfuryl ether from furfuryl alcohol to EMF mostly uses solid acid as catalyst. For example, Cao et al. (Catalysis Communications, 2015, 58: 76-79) reported that the yield of EMF was 58% under the action of ZSM-5 molecular sieve to catalyze the etherification reaction of furfuryl alcohol and ethanol, which was relatively low. Chaffey et al. (ACS Sustainable Chemistry & Engineering, 2018, 6 (4): 4996-5002) tried to add triethoxymethane as a promoter, and obtained a 73% yield of EMF under the catalysis of ZSM-5 molecular sieve, but this reaction process consumed an equal molar amount of triethoxymethane (27,000 yuan / t), so it was difficult to accept in terms of cost. Summary of the invention

[0005] The purpose of the present invention is to provide a process for preparing tetrahydrofurfuryl alcohol ether by a one-step method using furfural under the catalytic action of a supported bimetallic catalyst. The catalyst has the advantages of good catalytic activity and good catalyst stability, so as to solve the shortcomings of the prior art such as long process route and complicated operation.

[0006] In order to achieve the above-mentioned object, the present invention provides a method for preparing tetrahydrofurfuryl alcohol ether. The method comprises: using a reaction kettle as a reactor, using furfural and ethanol as reaction raw materials, and under the action of a specific catalyst, firstly making the reaction raw materials generate furfural ether under a first reaction condition, and then making the furfural ether generate tetrahydrofurfuryl alcohol ether under a second reaction condition, wherein the first reaction condition comprises: a reaction temperature of 40 to 120° C., a hydrogen pressure of 1 MPa to 10 MPa, and a reaction time of 6 to 10 h, and the second reaction condition comprises: a reaction temperature of 120 to 220° C., a hydrogen pressure of 1 MPa to 10 MPa, and a reaction time of 8 h to 14 h, wherein the catalyst is a supported bimetallic catalyst, denoted as MNi / ZSM-5, which comprises a carrier ZSM-5, and a noble metal M and a metal component Ni supported on the carrier ZSM-5, and the noble metal M is selected from one of Pd, Pt, Au, Ir, and Ru.

[0007] In a specific embodiment, the feed ratio of the catalyst, the furfural and the ethanol is: (2-4) g: (50-100) g: (100-200) mL.

[0008] In a specific embodiment, the precious metal is Pd, the first reaction conditions include: reaction temperature of 80-120°C, hydrogen pressure of 8MPa, reaction time of 8-10h, and the second reaction conditions include: reaction temperature of 180-200°C, hydrogen pressure of 9MPa, reaction time of 10h-14h.

[0009] In a specific embodiment, based on the total mass of the catalyst as 100%, the theoretical loading amount of the precious metal M in the MNi / ZSM-5 is 0.58-1.79wt%, and the theoretical loading amount of the metal component Ni is 8.94-16.43wt%; the Si / Al value of the carrier ZSM-5 is 10-40.

[0010] In a specific embodiment, based on the total mass of the catalyst as 100%, the theoretical loading amount of the precious metal M in the MNi / ZSM-5 is 0.86-0.93wt%, and the theoretical loading amount of the metal component Ni is 9.03-12.93wt%; the Si / Al value of the carrier ZSM-5 is 10-30.

[0011] In a specific embodiment, the supported bimetallic catalyst is prepared by the following method, comprising:

[0012] Step (1), preparing ZSM-5 molecular sieve according to a preset method, wherein the preset method includes:

[0013] Tetrapropylammonium hydroxide, ethyl orthosilicate, purified water and sodium aluminate are mixed according to a preset feed ratio, and stirred at room temperature for a first preset time to obtain a mixed solution, wherein the preset feed ratio of tetrapropylammonium hydroxide, ethyl orthosilicate, purified water and sodium aluminate is (25-30) g: (20-26) g: (80-100) mL: (0.13-0.79) g.

[0014] The mixed solution is placed in a hydrothermal kettle for crystallization to obtain a ZSM-5 molecular sieve precursor, wherein the crystallization conditions include: a crystallization temperature of 180 to 200° C. and a crystallization time of 24 to 48 hours.

[0015] The ZSM-5 molecular sieve precursor is centrifuged, washed, dried and calcined to obtain the ZSM-5 molecular sieve.

[0016] Step (2), preparing nickel solution and precious metal solution.

[0017] Step (3), dispersing the ZSM-5 molecular sieve prepared in step (1) in pure water, first adding the nickel solution and the noble metal solution, then adding ethylenediamine, and stirring at room temperature for a second preset time to obtain a catalyst precursor.

[0018] Step (4), washing, drying, calcining and reducing the catalyst precursor to obtain the supported bimetallic catalyst.

[0019] In a specific embodiment, the mass concentration of the nickel solution prepared in step (2) is 200-300 mg / mL, the mass concentration of the precious metal solution is 20-40 mg / mL, and in step (3), the feed ratio of ZSM-5 molecular sieve, purified water, M precursor solution, nickel solution and ethylenediamine is (5-10) g: (50-100) mL: (0.875-10) mL: (1.67-10) mL: (1-6) mL.

[0020] In a specific implementation, the first preset time is 6 to 8 hours, and the second preset time is 1 to 4 hours.

[0021] In a specific embodiment, in the step (4), the calcination conditions include: calcination in an air atmosphere, a calcination temperature of 550 to 650° C., and a calcination time of 5 to 8 hours.

[0022] In a specific embodiment, in step (4), the reduction conditions include: reduction under H2 / Ar atmosphere, a reduction temperature of 200 to 400°C, and a reduction time of 2 to 4 hours.

[0023] The beneficial effects of the present invention include at least:

[0024] 1. The present invention provides a method for preparing tetrahydrofurfuryl alcohol ether, the method comprising: using a reaction kettle as a reactor, using furfural and ethanol as reaction raw materials, under the action of a specific catalyst, first making the reaction raw materials generate furfural ether under a first reaction condition, and then making the furfural ether generate tetrahydrofurfuryl alcohol ether under a second reaction condition, the first reaction condition comprising: a reaction temperature of 40 to 120° C., a hydrogen pressure of 1 MPa to 10 MPa, and a reaction time of 6 to 10 h, the second reaction condition comprising: a reaction temperature of 120 to 220° C., a hydrogen pressure of 1 MPa to 10 MPa, and a reaction time of 8 h to 14 h, wherein the catalyst is a supported bimetallic catalyst, denoted as MNi / ZSM-5, which comprises a carrier ZSM-5, and a negative The noble metal M and the metal component Ni are carried on the carrier ZSM-5, and the noble metal M is selected from one of Pd, Pt, Au, Ir and Ru. In the method provided by the present invention, under the first reaction condition, a part of furfural and ethanol are catalyzed by the noble metal in the catalyst to generate furfural ether through acetalization and hydrogenolysis reaction, and another part of furfural is catalyzed by the acid of the catalyst carrier ZSM-5 molecular sieve to generate furfural ether through reduction etherification reaction, and the furfural ether generated by the two pathways is generated under the second reaction condition and the catalytic action of nickel in the catalyst to generate tetrahydrofurfuryl alcohol ether. In this way, by controlling the reaction conditions, the tetrahydrofurfuryl alcohol ether can be prepared from furfural in one step, which greatly shortens the process flow, saves the raw material cost, reduces the reaction energy consumption, and improves the ETE synthesis efficiency.

[0025] 2. The supported bimetallic catalyst provided by the present invention introduces the transition metal Ni on the surface of the noble metal M (M = Pd, Pt, Au, Ir, Ru), which not only generates electronic synergistic interaction between the bimetallics, but also improves the dispersion of metal nanoparticles on the carrier surface, thereby further optimizing the performance of the catalyst.

[0026] 3. The present invention adopts a supported bimetallic catalyst MNi / ZSM-catalyzed furfural to prepare tetrahydrofurfuryl alcohol ether, which has the advantages of good catalytic activity and high stability. In terms of catalytic activity, when the noble metal is selected from Pd, under the optimal reaction conditions (the first reaction conditions include: reaction temperature of 80°C, hydrogen pressure of 8MPa, reaction time of 8h, and the second reaction conditions include: reaction temperature of 180°C, hydrogen pressure of 9MPa, reaction time of 10h), the conversion rate of furfural reaches 100%, and the selectivity of tetrahydrofurfuryl alcohol ether reaches 79.5%; in terms of stability, there is almost no deactivation phenomenon after 10 applications, and it has good application prospects for industrial production of ETE. DETAILED DESCRIPTION

[0027] The present invention is described in detail below with reference to the embodiments.

[0028] The invention provides a method for preparing tetrahydrofurfuryl alcohol ether. The method comprises: using a reaction kettle as a reactor, using furfural and ethanol as reaction raw materials, and under the action of a specific catalyst, firstly making the reaction raw materials generate furfural ether under a first reaction condition, and then making the furfural ether generate tetrahydrofurfuryl alcohol ether under a second reaction condition, wherein the first reaction condition comprises: a reaction temperature of 40 to 120° C., a hydrogen pressure of 1 MPa to 10 MPa, and a reaction time of 6 to 10 hours, and the second reaction condition comprises: a reaction temperature of 120 to 220° C., a hydrogen pressure of 1 MPa to 10 MPa, and a reaction time of 8 to 14 hours, wherein the catalyst is a supported bimetallic catalyst, denoted as MNi / ZSM-5, comprising a carrier ZSM-5, and a noble metal M and a metal component Ni supported on the carrier ZSM-5, and the noble metal M is selected from one of Pd, Pt, Au, Ir and Ru.

[0029] The one-step preparation method of tetrahydrofurfuryl alcohol ether from furfural provided by the present invention is as follows:

[0030]

[0031] In the present invention, under the first reaction condition, a part of furfural and ethanol are catalyzed by the noble metal in the catalyst to generate furfural ether through acetalization and hydrogenolysis reaction, and another part of furfural is catalyzed by the acid of ZSM-5 molecular sieve as the carrier of the catalyst to generate furfural ether through reduction etherification reaction. The furfural ether generated by the two pathways is converted into tetrahydrofurfuryl alcohol ether under the second reaction condition and the catalytic action of nickel in the catalyst. The first reaction condition is reacted at a relatively low temperature, and the second reaction condition is carried out at a relatively high temperature, so as to make the furfural ether hydrogenated thoroughly and improve the yield of tetrahydrofurfuryl alcohol ether.

[0032] Preferably, the feed ratio of the catalyst, the furfural and the ethanol is: (2-4) g: (50-100) g: (100-200) mL.

[0033] Preferably, the precious metal is Pd, the first reaction conditions include: reaction temperature of 80-120°C, hydrogen pressure of 8MPa, and reaction time of 8-10h, and the second reaction conditions include: reaction temperature of 180-200°C, hydrogen pressure of 9MPa, and reaction time of 10h-14h.

[0034] More preferably, the noble metal is Pd, the first reaction conditions include: reaction temperature of 80°C, hydrogen pressure of 8MPa, and reaction time of 8h, and the second reaction conditions include: reaction temperature of 180°C, hydrogen pressure of 9MPa, and reaction time of 10h.

[0035] Preferably, based on the total mass of the catalyst as 100%, the theoretical loading amount of the noble metal M in the MNi / ZSM-5 is 0.58-1.79wt%, and the theoretical loading amount of the metal component Ni is 8.94-16.43wt%; the Si / Al value of the carrier ZSM-5 is 10-40.

[0036] More preferably, based on the total mass of the catalyst as 100%, the theoretical loading amount of the noble metal M in the MNi / ZSM-5 is 0.86-0.93wt%, and the theoretical loading amount of the metal component Ni is 9.03-12.93wt%; the Si / Al value of the carrier ZSM-5 is 10-30.

[0037] The supported bimetallic catalyst MNi / ZSM-5 provided by the present invention is prepared by the following method, comprising:

[0038] Step (1), preparing ZSM-5 molecular sieve according to a preset method, wherein the preset method includes:

[0039] (a) tetrapropylammonium hydroxide, ethyl orthosilicate, purified water and sodium aluminate are mixed according to a preset feed ratio, and stirred at room temperature for a first preset time to obtain a mixed solution, wherein the preset feed ratio of tetrapropylammonium hydroxide, ethyl orthosilicate, purified water and sodium aluminate is (25-30) g: (20-26) g: (80-100) mL: (0.13-0.79) g.

[0040] Preferably, the first preset time is 6 to 8 hours.

[0041] (b) placing the mixed solution in a hydrothermal reactor for crystallization to obtain a ZSM-5 molecular sieve precursor, wherein the crystallization conditions include: a crystallization temperature of 180 to 200° C. and a crystallization time of 24 to 48 hours.

[0042] (c) The ZSM-5 molecular sieve precursor is centrifuged, washed, dried and calcined to obtain the ZSM-5 molecular sieve.

[0043] Preferably, in step (c), the centrifugal conditions include: a centrifugal rate of 8000 to 16000 r / min, and a centrifugal time of 5 to 10 min.

[0044] Preferably, in step (c), washing is performed using pure water until the mixture becomes neutral.

[0045] Preferably, in step (c), the drying conditions include: drying temperature of 80 to 120° C., and drying time of 2 to 8 hours.

[0046] In the present invention, drying is performed using a forced air drying oven.

[0047] Preferably, in step (c), the calcination conditions include: placing the dried product under an inert atmosphere (preferably nitrogen or argon) of 30 to 50 mL / min, heating to 500 to 600° C. at a heating rate of 2 to 4° C. / min, and maintaining for 5 to 8 hours to obtain a calcined product.

[0048] Step (2), preparing nickel solution and precious metal solution.

[0049] Preferably, the mass concentration of the prepared nickel solution is 200-300 mg / mL, and the mass concentration of the precious metal solution is 20-40 mg / mL.

[0050] Preferably, the nickel solution is a nickel nitrate solution, and the noble metal solution is a H2PdCl4 solution.

[0051] Step (3), dispersing the ZSM-5 molecular sieve prepared in step (1) in pure water, first adding the nickel solution and the noble metal solution, then adding ethylenediamine, and stirring at room temperature for a second preset time to obtain a catalyst precursor.

[0052] Preferably, the feed ratio of the ZSM-5 molecular sieve, purified water, M precursor solution, nickel solution and ethylenediamine is (5-10) g: (50-100) mL: (0.875-10) mL: (1.67-10) mL: (1-6) mL.

[0053] Preferably, the second preset time is 1 to 4 hours.

[0054] Step (4), the catalyst precursor is washed, dried, calcined and reduced to obtain the supported bimetallic catalyst.

[0055] Preferably, in step (4), washing is performed using pure water until the mixture becomes neutral.

[0056] Preferably, in step (4), the drying conditions include: drying temperature of 80 to 120° C., and drying time of 2 to 8 hours.

[0057] Preferably, in step (4), the calcination conditions include: placing in an air atmosphere of 30 to 50 mL / min, heating to 550 to 650° C. at a heating rate of 2 to 4° C. / min, and maintaining for 5 to 8 hours.

[0058] Preferably, in step (4), the reduction treatment is specifically as follows: placing the calcined catalyst in a H2 / Ar atmosphere of 30 to 50 mL / min, with a heating rate of 2 to 4°C / min, a reduction temperature of 200 to 400°C, and a reduction time of 2 to 4 hours.

[0059] In the present invention, the H2 concentration in the H2 and Ar gases is 5%.

[0060] It should be noted that the catalyst in the following examples is recorded as A%MB%Ni / ZSM-5@C, wherein A% represents the theoretical loading amount of the precious metal in the catalyst, B% represents the theoretical loading amount of the metal component Ni in the catalyst, and C represents the Si / Al ratio when preparing the ZSM-5 molecular sieve, wherein the theoretical loading amounts of the metal component Ni and the precious metal M are both based on the total mass of the catalyst as 100%.

[0061] Preparation of supported bimetallic catalyst MNi / ZSM-5

[0062] Example 1

[0063] 1.1 Preparation of ZSM-5 molecular sieve (Si / Al=10)

[0064] Step 1.1.1, preparation of ZSM-5 molecular sieve precursor: 25g of tetrapropylammonium hydroxide (TPAOH), 20g of tetraethyl orthosilicate (TEOS), 80mL of purified water, and 0.79g of sodium aluminate (NaAlO2) were mixed, and stirred at a rate of 1000r / min at room temperature for 6h to obtain a mixed solution, and the mixed solution was transferred to a hydrothermal autoclave for crystallization at 180°C for 24h to obtain a ZSM-5 molecular sieve precursor.

[0065] Step 1.1.2: Centrifuge the ZSM-5 molecular sieve precursor synthesized in step 1.1.1 at a rate of 16000 r / min for 5 min to obtain a white solid powder.

[0066] Step 1.1.3: Wash the white powder obtained after centrifugation in step 1.1.2 with purified water until it becomes neutral, and dry it at 120°C for 4 hours.

[0067] Step 1.1.4: Place the product dried in step 1.1.3 in a 30 mL / min N2 atmosphere, heat to 550°C at a heating rate of 2°C / min, and maintain for 6 h to obtain a calcined product.

[0068] 1.2 Configuration of metal impregnation solution:

[0069] Nickel nitrate hexahydrate was dissolved in purified water and stirred to dissolve, thereby preparing a Ni(NO3)2·6H2O aqueous solution with a concentration of 300 mg / mL.

[0070] 1.3 Configuration of precious metal impregnation solution:

[0071] PdCl2 solution was added to HCl solution and stirred to dissolve it to obtain H2PdCl4 solution with a concentration of 40 mg / mL.

[0072] 1.4 Preparation of catalyst precursor

[0073] Disperse 5 g of the ZSM-5 molecular sieve prepared in step 1.1 in 50 mL of purified water, add 1.67 mL of the Ni(NO3)2·6H2O aqueous solution prepared in step 1.2 and 0.875 mL of the H2PdCl4 solution prepared in step 1.3, then add 3 mL of ethylenediamine, and stir at room temperature at a rate of 800 r / min for 2 h.

[0074] 1.5 Preparation of catalyst

[0075] The catalyst precursor prepared in step 1.4 is sequentially washed, dried and calcined to obtain a catalyst to be reduced, wherein the catalyst is washed with purified water until neutral; the drying condition is 120°C for 4 hours; the calcination condition is: in an air atmosphere of 30 mL / min, the temperature is increased to 550°C at a heating rate of 2°C / min and maintained for 6 hours.

[0076] 1.6 Catalyst reduction

[0077] The catalyst calcined in step 1.5 was placed in 30 mL of H2 / Ar (H2 concentration was 5%), heated to 400°C at a heating rate of 2°C / min, and maintained for 2 h to obtain a supported bimetallic catalyst 0.63% Pd9.05% Ni / ZSM-5@10.

[0078] Example 2

[0079] Example 2 is the same as Example 1, except that 2.5 mL of metal impregnation solution [Ni(NO3)2·6H2O aqueous solution] is added during the preparation of the catalyst precursor in step 1.4, and the catalyst prepared in Example 2 is recorded as 0.61% Pd12.96% Ni / ZSM-5@10.

[0080] Example 3

[0081] Example 3 is the same as Example 1, except that 3.3 mL of metal impregnation solution [Ni(NO3)2·6H2O aqueous solution] is added during the preparation of the catalyst precursor in step 1.4, and the catalyst prepared in Example 2 is recorded as 0.58% Pd16.43% Ni / ZSM-5@10.

[0082] Example 4

[0083] Example 4 is the same as Example 1, except that 0.394 g of sodium aluminate is added in step 1.1.1. At this time, Si / Al of the ZSM-5 molecular sieve carrier is 20, and the catalyst prepared in Example 4 is recorded as 0.63% Pd9.05% Ni / ZSM-5@20.

[0084] Example 5

[0085] Example 5 is the same as Example 1, except that 0.263 g of sodium aluminate is added in step 1.1.1. At this time, Si / Al of the ZSM-5 molecular sieve carrier is 30, and the catalyst prepared in Example 4 is recorded as 0.63% Pd9.05% Ni / ZSM-5@30.

[0086] Example 6

[0087] Example 6 is the same as Example 1, except that 0.20 g of sodium aluminate is added in step 1.1.1. At this time, Si / Al of the ZSM-5 molecular sieve carrier is 40, and the catalyst prepared in Example 4 is recorded as 0.63% Pd9.05% Ni / ZSM-5@40.

[0088] Example 7

[0089] Example 7 is the same as Example 1, except that 1.25 mL of the precious metal impregnation solution H2PdCl4 solution is added in step 1.4 when preparing the catalyst precursor, and the catalyst prepared in Example 7 is recorded as 0.90% Pd9.03% Ni / ZSM-5@10.

[0090] Example 8

[0091] Example 8 is the same as Example 1, except that 2.5 mL of the precious metal impregnation solution H2PdCl4 solution is added in step 1.4 when preparing the catalyst precursor, and the catalyst prepared in Example 7 is recorded as 1.79% Pd8.94% Ni / ZSM-5@10.

[0092] Example 9

[0093] Example 9 is the same as Example 1, and the difference from Example 1 is that: 1) 0.263 g of sodium aluminate is added in step 1.1.1, and at this time, Si / Al of the ZSM-5 molecular sieve carrier is 30; 2) 1.25 mL of the precious metal impregnation solution H2PdCl4 solution is added in step 1.4 when preparing the catalyst precursor, and 2.5 mL of the metal impregnation solution [Ni(NO3)2·6H2O aqueous solution] is added; the catalyst prepared in Example 9 is recorded as 0.86% Pd12.93% Ni / ZSM-5@30.

[0094] Example 10

[0095] Example 10 is the same as Example 9, except that the precious metal impregnation solution added in step 1.4 when preparing the catalyst precursor is H2PtCl6 solution, and the added amount is the same. The catalyst prepared in Example 9 is recorded as 0.86% Pt12.93% Ni / ZSM-5@30.

[0096] Embodiment 11

[0097] Example 11 is the same as Example 9, except that the precious metal impregnation solution added in step 1.4 when preparing the catalyst precursor is HAuCl4·4H2O solution, and the added amount is the same. The catalyst prepared in Example 9 is recorded as 0.86% Au12.93% Ni / ZSM-5@30.

[0098] Example 12

[0099] Example 12 is the same as Example 9, except that the precious metal impregnation solution added in step 1.4 when preparing the catalyst precursor is IrCl3·3H2O solution, and the added amount is the same. The catalyst prepared in Example 9 is recorded as 0.86%Ir12.93%Ni / ZSM-5@30.

[0100] Embodiment 13

[0101] Example 13 is the same as Example 9, except that the precious metal impregnation solution added in step 1.4 when preparing the catalyst precursor is RuCl3·3H2O, and the added amount is the same. The catalyst prepared in Example 9 is recorded as 0.86%Ru12.93%Ni / ZSM-5@30.

[0102] Comparative Example 1

[0103] Comparative Example 1 is the same as Example 1, except that the precious metal impregnation solution H2PdCl4 solution added in step 1.4 when preparing the catalyst precursor is 0 mL (ie, no precious metal impregnation solution is added), and the catalyst prepared in Comparative Example 1 is recorded as 9.11% Ni / ZSM-5@10.

[0104] Comparative Example 2

[0105] Comparative Example 2 is the same as Example 1, except that the metal impregnation solution [Ni(NO3)2·6H2O aqueous solution] added in step 1.4 when preparing the catalyst precursor is 0 mL (i.e., no nickel impregnation solution is added), and the catalyst prepared in Comparative Example 2 is recorded as 0.7% Pd / ZSM-5@10.

[0106] Comparative Example 3

[0107] Comparative Example 3 is the same as Example 1, except that the amount of sodium aluminate added in step 1.1.1 is 0 g (i.e., no sodium aluminate is added). At this time, the ZSM-5 molecular sieve carrier contains only silicon. The catalyst prepared in Comparative Example 3 is recorded as 0.63% Pd9.05% Ni / ZSM-5 (01).

[0108] Comparative Example 4

[0109] Comparative Example 4 is the same as Example 1, except that 0 g of tetraethyl orthosilicate is added in step 1.1.1. At this time, the ZSM-5 molecular sieve carrier contains only Al. The catalyst prepared in Comparative Example 4 is recorded as 0.63% Pd9.05% Ni / ZSM-5(02).

[0110] Comparative Example 5

[0111] Comparative Example 5 is the same as Example 1, except that 0 mL of ethylenediamine is added in step 1.4 when preparing the catalyst precursor (ie, no ethylenediamine is added). The catalyst prepared in Comparative Example 5 is recorded as 0.63% Pd9.05% Ni / ZSM-5(03).

[0112] The important parameters of the catalysts of Preparation Examples 1 to 13 and Comparative Examples 1 to 5 are summarized, as shown in Table 1.

[0113] Table 1 Catalyst data of Examples 1 to 13 and Comparative Examples 1 to 5

[0114]

[0115] Catalyst activity evaluation

[0116] Specifically, the catalysts prepared in Examples 1 to 13 and Comparative Examples 1 to 5 were used in the reaction of preparing tetrahydrofurfuryl alcohol ether by etherification and hydrogenation of furfural, and the conversion rate of furfural and the selectivity of tetrahydrofurfuryl alcohol ether were calculated to evaluate the activity of the catalyst.

[0117] The specific operation is: weigh 50g of furfural into a 500mL autoclave, add 2.5g of the catalyst prepared above and 100mL of ethanol, and replace the autoclave with H2 three times; the reaction is divided into two stages, the reaction conditions of the first stage include: reaction temperature 80℃, H2 pressure 8MPa, stirring speed 700r / min, reaction for 8h; the reaction conditions of the second stage include: reaction temperature 180℃, H2 pressure 9MPa, stirring speed 700r / min, reaction for 10h. The specific results are shown in Table 2.

[0118] Table 2 Catalytic activity of catalysts prepared in Examples 1 to 13 and Comparative Examples 1 to 5

[0119] catalyst Furfural conversion rate / % Tetrahydrofurfuryl alcohol ether selectivity / % Example 1 84.2 58.1 Example 2 89.7 59.6 Example 3 85.1 54.3 Example 4 90.2 67.8 Example 5 93.8 70.3 Example 6 91.3 68.4 Example 7 100 78.5 Example 8 88.5 75.2 Example 9 100 79.5 Example 10 81.5 53.6 Embodiment 11 80.4 53.0 Example 12 79.5 52.2 Embodiment 13 79.1 51.7 Comparative Example 1 58.1 20.2 Comparative Example 2 57.3 22.9 Comparative Example 3 39.1 22.1 Comparative Example 4 70.4 19.4 Comparative Example 5 72.6 48.7

[0120] According to the data comparison of Examples 1 to 9 in Table 2, the Pd content, Ni content in the catalyst and the Si / Al ratio in ZSM-5 have an important influence on the reaction performance of furfural etherification and hydrogenation to prepare tetrahydrofurfuryl alcohol ether. Pd metal is conducive to the hydrogenolysis of the acetal intermediate generated by the furfural acetal reaction to form furfuryl ether, and Ni metal activates and dissociates H2 in the second stage furfuryl ethanol hydrogenation reaction, promoting the formation of tetrahydrofurfuryl alcohol ether (ETE). If the Pd metal loading is low, it may lead to insufficient active sites on the catalyst surface and decreased activity. Excessive Pd loading may greatly increase the metal particle size, uneven dispersion, and decreased reaction rate. If the Ni metal content is low, the dissociative adsorption of H2 molecules is incomplete, but a higher Ni loading may lead to excessive hydrogenation reaction and reduced ETE selectivity. The smaller the Si / Al ratio in the ZSM-5 carrier, the more Bronsted acid sites there are on the carrier surface, which is conducive to the reduction and etherification of furfural (Fu) to furfural ether. However, if the Si / Al ratio is too small, it may lead to excessive hydrogenation of furfural (Fu) to form by-products such as tetrahydrofurfuryl alcohol.

[0121] Therefore, the proper adjustment of the bimetallic loading and the Si / Al ratio of ZSM-5 plays an important guiding role in optimizing the preparation of ETE by Fu etherification hydrogenation. When the Pd metal loading is 0.86wt%, the Ni metal loading is 12.93wt%, and the Si / Al ratio of the ZSM-5 carrier is 30, the conversion rate of furfural Fu is as high as 100%, and the selectivity of tetrahydrofurfuryl alcohol ether ETE is 79.5%.

[0122] Comparing the conversion rate data and selectivity data corresponding to Examples 9 to 13 in Table 2, it can be seen that when Pd is selected as the precious metal, the conversion rate of furfural and the selectivity of tetrahydrofurfuryl alcohol ether are the highest. If the Pd metal is replaced by Pt, Au, Ir and Ru, the hydrogenolysis ability of the acetal intermediate may be weakened, the selectivity of furfuryl ether is reduced, and it is not conducive to the formation of ETE.

[0123] Comparing the conversion rate data and selectivity data of Example 1 and Comparative Examples 1-5 in Table 2, it can be seen that if Pd or Ni metal components are not added, the hydrogenolysis of the acetal product and the hydrogenation performance of the furan ring are lost during the reaction, and the catalyst performance is significantly reduced. In the preparation process of the catalyst, if NaAlO2 is not added, the Bronsted acid sites on the catalyst surface are greatly reduced, and the formation of the acetal product and the etherification of furfuryl alcohol to form furfuryl ether cannot be promoted. If tetraethyl orthosilicate is not added, the surface acid sites of the ZSM-5 carrier are too many, causing the intermediate furfuryl alcohol to be excessively hydrogenated to generate tetrahydrofurfuryl alcohol, reducing the selectivity of furfuryl ether. If ethylenediamine is not added, the metal particle size cannot be accurately regulated, reducing the activity of the catalyst.

[0124] Optimization of reaction conditions

[0125] Examples 14-26 used the catalyst prepared in Example 9 to carry out catalytic reactions. The reaction conditions and catalytic activities for preparing tetrahydrofurfuryl alcohol ether by furfural etherification and hydrogenation are shown in Table 3.

[0126] Table 3 Effect of reaction conditions on the performance of ETE prepared by Fu etherification hydrogenation

[0127]

[0128]

[0129] It should be noted that, in Examples 14 to 26, the amount of catalyst used was 2.5 g; the amount of ethanol used was 100 mL; the stirring rate was 700 r / min, and other conditions are detailed in Table 3.

[0130] Comparing the reaction conditions and catalytic activity data of Examples 14 to 19 in Table 3, it can be seen that the optimal reaction temperature in the first reaction condition of the catalyst is 80°C. When the temperature is lower than 80°C, the hydrogenation rate is slow and the conversion rate is low. If the reaction temperature is higher than 80°C, excessive hydrogenation reaction may occur, reducing the selectivity of furfuryl ether in the first stage reaction. Similarly, the optimal temperature in the second reaction condition is 180°C.

[0131] From the data of Examples 14, 22, and 23 in Table 3, it can be concluded that the H2 pressure in the first reaction condition is 8 MPa, and the H2 pressure in the second reaction condition is 9 MPa, the reaction effect is optimal, Fu is completely converted, and the selectivity of ETE is close to 80%.

[0132] Comparing the catalytic activity data of Example 14 and Examples 24 to 26 in Table 3, it can be seen that the best effect is achieved when the reaction time is 8 h in the first reaction condition and 10 h in the second reaction condition. A short reaction time may lead to incomplete hydrogenolysis and hydrogenation, while a long reaction time may lead to excessive hydrogenation and an increase in the content of by-products.

[0133] Comparing the catalytic activity data of Example 14 and Examples 20 to 21 in Table 3, it can be seen that the optimal amount of Fu is 50.0 g, and increasing the amount of Fu may result in incomplete reaction of part of Fu.

[0134] Catalyst stability evaluation

[0135] According to the reaction process conditions of Example 14, the cyclic stability of the catalyst of Example 9 was evaluated by preparing ETE through Fu etherification and hydrogenation in a reactor. The evaluation results are shown in Table 4.

[0136] Table 4 Cyclic stability performance test of catalyst

[0137]

[0138]

[0139] From the data in Table 4, it can be seen that after the catalyst was used 10 times, the Fu conversion rate and ETE selectivity were basically stable. In the 10th application, the Fu conversion rate was still greater than 99%, the ETE selectivity was 78.6%, and there was almost no deactivation phenomenon. This shows that the catalyst has good cycle stability and has good application prospects for industrial production of ETE.

[0140] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions and substitutions can be made without departing from the concept of the present invention, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. A method for preparing tetrahydrofurfuryl alcohol ethyl ether, characterized in that, The method comprises: using a reaction kettle as a reactor, using furfural and ethanol as reaction raw materials, and under the action of a specific catalyst, firstly generating furfural ether from the reaction raw materials under a first reaction condition, and then generating tetrahydrofurfuryl alcohol ether from the furfural ether under a second reaction condition, wherein the first reaction condition comprises: a reaction temperature of 40 to 120° C., a hydrogen pressure of 1 MPa to 10 MPa, and a reaction time of 6 to 10 h, and the second reaction condition comprises: a reaction temperature of 120 to 220° C., a hydrogen pressure of 1 MPa to 10 MPa, and a reaction time of 8 to 14 h, wherein the catalyst is a supported bimetallic catalyst, denoted as MNi / ZSM-5, comprising a carrier ZSM-5, and a noble metal M and a metal component Ni supported on the carrier ZSM-5, wherein the noble metal M is selected from one of Pd, Pt, Au, Ir, and Ru.

2. The preparation method of tetrahydrofurfuryl alcohol ethyl ether according to claim 1, characterized in that, The feed ratio of the catalyst, the furfural and the ethanol is: (2-4) g: (50-100) g: (100-200) mL.

3. The preparation method of tetrahydrofurfuryl alcohol ethyl ether according to claim 1, characterized in that, The precious metal is Pd, the first reaction conditions include: reaction temperature of 80-120°C, hydrogen pressure of 8MPa, and reaction time of 8-10h, and the second reaction conditions include: reaction temperature of 180-200°C, hydrogen pressure of 9MPa, and reaction time of 10h-14h.

4. The method for preparing tetrahydrofurfuryl alcohol ethyl ether according to any one of claims 1 to 3, characterized in that: Based on the total mass of the catalyst as 100%, the theoretical loading amount of the noble metal M in the MNi / ZSM-5 is 0.58-1.79wt%, the theoretical loading amount of the metal component Ni is 8.94-16.43wt%, and the Si / Al value of the carrier ZSM-5 is 10-40.

5. The method for preparing tetrahydrofurfuryl alcohol ethyl ether according to claim 4, characterized in that: Based on the total mass of the catalyst as 100%, the theoretical loading amount of the noble metal M in the MNi / ZSM-5 is 0.86-0.93wt%, the theoretical loading amount of the metal component Ni is 9.03-12.93wt%, and the Si / Al value of the carrier ZSM-5 is 10-30.

6. The method for preparing tetrahydrofurfuryl alcohol ethyl ether according to claim 4, characterized in that: The supported bimetallic catalyst is prepared by the following method, comprising: Step (1), preparing ZSM-5 molecular sieve according to a preset method, wherein the preset method includes: Tetrapropylammonium hydroxide, ethyl orthosilicate, purified water and sodium aluminate are mixed according to a preset feed ratio, and stirred at room temperature for a first preset time to obtain a mixed solution, wherein the preset feed ratio of tetrapropylammonium hydroxide, ethyl orthosilicate, purified water and sodium aluminate is (25-30) g: (20-26) g: (80-100) mL: (0.13-0.79) g; The mixed solution is placed in a hydrothermal reactor for crystallization to obtain a ZSM-5 molecular sieve precursor, wherein the crystallization conditions include: a crystallization temperature of 180 to 200° C. and a crystallization time of 24 to 48 hours; The ZSM-5 molecular sieve precursor is centrifuged, washed, dried and calcined to obtain the ZSM-5 molecular sieve; Step (2), preparing nickel solution and precious metal solution; Step (3), dispersing the ZSM-5 molecular sieve prepared in step (1) in pure water, first adding the nickel solution and the noble metal solution, then adding ethylenediamine, and stirring at room temperature for a second preset time to obtain a catalyst precursor; Step (4), washing, drying, calcining and reducing the catalyst precursor to obtain the supported bimetallic catalyst.

7. The method for preparing tetrahydrofurfuryl alcohol ethyl ether according to claim 6, characterized in that: The mass concentration of the nickel solution prepared in step (2) is 200-300 mg / mL, and the mass concentration of the precious metal solution is 20-40 mg / mL. In step (3), the feed ratio of ZSM-5 molecular sieve, purified water, M precursor solution, nickel solution and ethylenediamine is (5-10) g: (50-100) mL: (0.875-10) mL: (1.67-10) mL: (1-6) mL.

8. The method for preparing tetrahydrofurfuryl alcohol ethyl ether according to claim 6, characterized in that: The first preset time is 6 to 8 hours, and the second preset time is 1 to 4 hours.

9. The method for preparing tetrahydrofurfuryl alcohol ethyl ether according to claim 6, characterized in that: In the step (4), the calcination conditions include: calcination in an air atmosphere, a calcination temperature of 550 to 650° C., and a calcination time of 5 to 8 hours.

10. The method for preparing tetrahydrofurfuryl alcohol ethyl ether according to claim 6, characterized in that: In the step (4), the reduction conditions include: reduction under H2 / Ar atmosphere, a reduction temperature of 200 to 400°C, and a reduction time of 2 to 4 hours.

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