Catalyst for synthesizing 1,4-diacetoxy-2-butene, preparation method and application thereof

Abstract

The present invention discloses a catalyst for synthesizing 1,4-diacetoxy-2-butene, its preparation method and application. The catalyst includes a carrier, a main active metal, and a co-active metal; the main active metal includes Pd, the co-active metal includes Te and / or Sn, and the carrier is silica modified with carbon quantum dots. The catalyst provided by the present invention is used in the synthesis reaction of 1,4-diacetoxy-2-butene, and has the characteristics of high selectivity of 1,4-diacetoxy-2-butene and few by-products.

Description

Technical Field

[0001] The present invention relates to a catalyst for synthesizing 1,4-diacetoxy-2-butene, a preparation method thereof, and an application thereof. Background Art

[0002] 1,4-Butanediol (1,4-BDO) is an important organic and fine chemical raw material, which is widely used in the fields of medicine, chemical industry, textile, paper making, automobile and daily chemical industry, etc. It can be derived into a series of high-value-added fine chemical products. For example, tetrahydrofuran (THF), polybutylene terephthalate (PBT), γ-butyrolactone (GBL) and polyurethane resin (PU Resin) can be produced from 1,4-BDO. Especially as the basic raw material for producing PBT engineering plastics and PBT fibers, it has received extensive attention from research institutions.

[0003] There are relatively many process routes for the preparation of 1,4-butanediol. Classified by the raw materials used, there are raw material routes such as acetylene, ethylene, propylene, butadiene and maleic anhydride, and the same raw materials also have different synthesis processes. Due to high technical barriers and limited raw material sources, the global production of 1,4-BDO is relatively concentrated. In 2011, the global production capacity of 1,4-BDO was mainly distributed in Asia, the United States and Europe, among which the production capacity of 1,4-BDO in Asia accounted for as high as 56.6%.

[0004] As is well known, the butadiene acetoxylation method is a three-step process, that is, first, butadiene undergoes an acetylation reaction with acetic acid and oxygen to generate 1,4-diacetoxybutene and the by-product 3,4-diacetoxybutene; then 1,4-diacetoxybutene is catalytically hydrogenated to generate 1,4-diacetoxybutane, and finally a hydrolysis reaction is carried out to obtain 1,4-BDO. In the process route from 1,4-butadiene to 1,4-butanediol, the catalytic hydrogenation of 1,4-diacetoxybutene to generate 1,4-diacetoxybutane is one of the steps, and the yield and selectivity of the hydrogenation product directly affect the yield and selectivity of 1,4-butanediol relative to 1,4-butadiene.

[0005] In China, the existing production capacity of butadiene is in surplus. With the rapid development of the BDO market, there are obvious raw material and price advantages in preparing BDO from butadiene in areas rich in butadiene. The key technical step in the process of preparing 1,4-butanediol from the butadiene route is the oxyacetylation of butadiene to generate 1,4-diacetoxy-2-butene. The main by-product of this step reaction is 3,4-diacetoxy-1-butene. Therefore, improving the selectivity of this reaction can significantly improve the economic benefits of this technical route. Summary of the Invention

[0006] The technical problem to be solved by the present invention is the problem of low selectivity in the prior art of the synthesis method of 1,4-diacetoxy-2-butene, and a catalyst for synthesizing 1,4-diacetoxy-2-butene, its preparation method and application are provided. This catalyst is used in the synthesis reaction of 1,4-diacetoxy-2-butene, and has the characteristics of high selectivity of 1,4-diacetoxy-2-butene and few by-products.

[0007] In the first aspect of the present invention, a catalyst for synthesizing 1,4-diacetoxy-2-butene is provided, which includes a carrier, a main active metal, and a co-active metal;

[0008] The main active metal includes Pd, and the co-active metal includes Te and / or Sn; the carrier is silica modified with carbon quantum dots.

[0009] Further, in the catalyst, based on the weight of the catalyst, the weight content of the carrier is 97.0-99.8%, the weight content of the main active metal is 0.1-1.5%, and the weight content of the co-active metal is 0.1-1.5%.

[0010] Further, in the infrared spectrum of the catalyst, there is a bimodal distribution in the range of 900-1400 cm -1 which are the absorption peaks of Si-O-Si and Si-O-C respectively.

[0011] Further, in the infrared spectrum of the catalyst, peak A is the absorption peak of Si-O-Si, and there is an absorption peak in the range of 1000-1100 cm -1 peak B is the absorption peak of Si-O-C, and there is an absorption peak in the range of 1100-1200 cm -1 The intensity ratio of peak A to peak B is 1:0.1-10, preferably 1:0.6-4.0. Among them, the intensity ratio of peak A to peak B is the intensity ratio of the highest peaks of the two.

[0012] In the second aspect of the present invention, a preparation method of the above catalyst for synthesizing 1,4-diacetoxy-2-butene is provided, which includes the following steps:

[0013] (1) Preparation of catalyst carrier: Dry rice husks are mixed with a strong acid solution, and after heat treatment, carrier i is obtained; Carrier i and silica microspheres are heat-treated in an aqueous solution and dried to obtain the catalyst carrier;

[0014] (2) Preparation of catalyst: The catalyst carrier in step (1) is impregnated with solution A containing the main active metal and the co-active metal to obtain catalyst precursor I; Then, after reduction and drying, the catalyst is prepared.

[0015] Further, in step (1), the strong acid is selected from strong acids with strong oxidizing properties and low volatility, preferably sulfuric acid.

[0016] Further, in step (1), the concentration of the strong acid solution is 0.2 - 5 mol / L.

[0017] Further, in step (1), the mass ratio of the dry rice husk to the strong acid solution is 1:1 - 50.

[0018] Further, in step (1), the heat treatment is carried out dynamically, the heat treatment temperature is 50 - 100 °C, the treatment time is 1 - 10 h, and the stirring speed is 300 - 600 rpm.

[0019] Further, in step (1), the mass ratio of the carrier i to the silica microspheres is 1:2 - 16.

[0020] Further, in step (1), the heat treatment conditions of the carrier i and the silica microspheres in the aqueous solution are 150 - 200 °C, the time is 2 - 12 h, and it is carried out under stirring, and the stirring speed is 300 - 600 rpm.

[0021] Further, in step (1), the drying conditions are 60 - 120 °C, and the time is 24 - 100 h.

[0022] Further, in step (2), the content of the main active metal in the solution A is 0.3 - 10 g / L, and the content of the co - active metal is 0.3 - 10 g / L. The main active metal includes Pd, and the co - active metals include Te and / or Sn.

[0023] Further, in step (2), the volume ratio of the addition amount of the catalyst carrier to the solution A is 1:0.8 - 1.5.

[0024] Further, in step (2), the impregnation is equal - volume impregnation, and the impregnation time is 2 - 16 h.

[0025] Further, in step (2), the reduction step is carried out in a reducing atmosphere, such as a hydrogen atmosphere; the gas hourly space velocity in the reducing atmosphere is 60 - 600 h -1 , the pressure is 0.3 - 0.6 MPa, the reduction temperature is 100 - 300 °C, and the reduction time is 2 - 8 h.

[0026] Further, in step (2), the drying conditions are 60 - 120 °C, and the time is 2 - 24 h.

[0027] The third aspect of the present invention provides the application of the above - mentioned catalyst in the reaction for synthesizing 1,4 - diacetoxy - 2 - butene.

[0028] Further, in the presence of the catalyst, a raw material including air, butadiene and acetic acid reacts to obtain 1,4 - diacetoxy - 2 - butene.

[0029] Further, in terms of molar ratio, the composition of the raw materials is butadiene: air: acetic acid = 1: a: b, where a = 1 - 4 and b = 2 - 5; and / or preferably, the reaction pressure is 1.5 - 4.0 MPa; and / or, preferably the reaction temperature is 60 - 140 °C.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] The catalyst for synthesizing 1,4 - diacetoxy - 2 - butene provided by the present invention, compared with the conventional silica carrier, uses carbon quantum dot - modified silica as the carrier in the reaction for synthesizing 1,4 - diacetoxy - 2 - butene, significantly improving the yield of 1,4 - diacetoxy - 2 - butene, especially having a high selectivity. Description of the Drawings

[0032] Figure 1 It is the infrared spectrum of the catalysts in Example 1 and Comparative Example 1. Detailed Embodiments

[0033] The present invention will be specifically described below in combination with specific embodiments. The following embodiments are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described by referring to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words rather than limiting words. Modifications can be made to the present invention within the scope of the claims of the present invention as specified, and the present invention can be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same functions.

[0034] In the present invention, in the examples and comparative examples, the infrared spectra were measured using a Nicolet iS50 Fourier transform infrared spectrometer. The characterization method is as follows: A certain amount of KBr and the catalyst are ground into a powder, pressed into a tablet and placed in the sample cell of the infrared spectrometer, and the test resolution is 4 cm -1 , the number of scans is 64 times, and the scanning range is 400 - 4000 cm -1 for sample measurement.

[0035] In the present invention, the content of the active component in the catalyst is obtained by analysis using XRF (X-ray fluorescence spectrometry). The characterization method is as follows: Take a certain amount of the catalyst and grind it into a powder with a mesh size of 60 - 100 in a ball mill. Put the powder into an XRF sample cell for analysis and compare it with the measured standard curve to obtain the content of each element in the catalyst.

[0036] In the present invention, the yield of 1,4-diacetoxy-2-butene refers to the amount of product obtained per hour, which is the mass of the crude product obtained per hour multiplied by the content of the target product in the crude product.

[0037] In the present invention, the selectivity calculation formula of the catalyst for butadiene is as follows:

[0038]

[0039] In the present invention, the molar amount of one of the raw materials, air, is calculated according to the ideal gas formula, assuming an average molecular weight of 29 for air for conversion.

[0040]

Example 1

[0041] 1. Catalyst preparation

[0042] ① Preparation of catalyst support

[0043] (1) Take 15 g of dry rice husks and add them to 500 ml of a sulfuric acid solution with a concentration of 1 mol / L. Stir and heat at 80 °C for 5 h, with a stirring speed of 450 rpm. Filter, wash with water, and dry at 80 °C for 3 h to obtain support i;

[0044] (2) Take 5 g of support i and 40 g of silica microspheres and add them to 2400 ml of an aqueous solution. Stir and heat in an autoclave at 175 °C for 5 h, with a stirring speed of 450 rpm. Centrifuge the resulting liquid to obtain support ii;

[0045] (3) Dry support ii in an air atmosphere at 70 °C for 72 h to obtain the catalyst support.

[0046] ② Catalyst preparation

[0047] (1) Take 120 ml of a solution containing chloropalladic acid and tellurous acid, where the content of palladium in the solution is 2.75 g / L and the content of tellurium is 3.0 g / L. Add 130 ml of the catalyst support prepared in step ①, mix evenly, and impregnate for 12 h to obtain catalyst precursor I;

[0048] (2) Reduce catalyst precursor I in a hydrogen atmosphere, with a hydrogen space velocity of 120 hr -1 , a pressure of 0.5 MPa, a reduction temperature of 150 °C, and a reduction time of 4 h to obtain catalyst precursor II;

[0049] (3) The finished catalyst is prepared by drying the catalyst precursor II at 80 °C for 2 h.

[0050] The composition of the catalyst is shown in Table 1, and the infrared spectrum is shown in Figure 1 , the same as Figure 1 As can be seen, there are double peaks A and B at 1014.8 and 1138.1 cm -1 respectively, which also proves the formation of silica carbon quantum in this catalyst. The double peaks are the absorption peaks of Si-O-Si and Si-O-C respectively, and the intensity ratio of peak A to peak B is about 1:1.1.

[0051] 2. Catalyst evaluation

[0052] The evaluation is carried out in a batch reactor, and the specific conditions are as follows:

[0053] Catalyst loading volume: 100 ml;

[0054] Raw material feed: Butadiene flow rate: 37.3 g / h, acetic acid flow rate: 147 g / h, air flow rate: 52 L / h;

[0055] Reaction pressure: 2.2 MPa;

[0056] Reaction temperature: 100 °C;

[0057] Reaction time: 5 h;

[0058] The contents of each component in the reaction product are analyzed by gas chromatography, and the obtained test result data are listed in Table 1.

[0059]

Example 2

[0060] 1. Catalyst preparation

[0061] ① Preparation of catalyst support

[0062] (1) Take 15 g of dry rice husk and add it to 500 ml of sulfuric acid solution with a concentration of 0.5 mol / L. Stir and heat at 80 °C for 5 h, with a stirring speed of 450 rpm. Filter, wash with water, and dry at 80 °C for 3 h to obtain support i;

[0063] (2) Take 5 g of support i and 40 g of silica microspheres and add them to 2400 ml of aqueous solution. Stir and heat in an autoclave at 175 °C for 5 h, with a stirring speed of 450 rpm. Centrifuge the obtained liquid to obtain support ii;

[0064] (3) Dry support ii in an air atmosphere at 70 °C for 72 h to obtain the catalyst support.

[0065] ② Catalyst preparation

[0066] (1) Take 120 ml of a solution containing chloropalladic acid and telluric acid, where the palladium content in the solution is 2.75 g / L and the telluric acid content is 3.0 g / L. Add 130 ml of the catalyst support prepared in step ①, mix evenly, and impregnate for 12 h to obtain catalyst precursor I;

[0067] (2) Reduce catalyst precursor I in a hydrogen atmosphere with a hydrogen space velocity of 120 h -1 , a pressure of 0.5 MPa, a reduction temperature of 150 °C, and a reduction time of 4 h to obtain catalyst precursor II;

[0068] (3) Dry catalyst precursor II at 80 °C for 2 h to obtain the finished catalyst.

[0069] The composition of the catalyst is shown in Table 1, and the infrared spectrum is similar to that of Figure 1 Example 1. The intensity ratio of peak A to peak B is about 1:0.85.

[0070] 2. Catalyst evaluation

[0071] Evaluate using a stirred tank reactor with the following specific conditions:

[0072] Catalyst loading volume: 100 ml;

[0073] Raw material feed: Butadiene flow rate: 37.3 g / h, acetic acid flow rate: 147 g / h, air flow rate: 52 L / h;

[0074] Reaction pressure: 2.2 MPa;

[0075] Reaction temperature: 100 °C;

[0076] Reaction time: 5 h;

[0077] Analyze the content of each component in the reaction product by gas chromatography, and the test result data are listed in Table 1.

[0078]

Example 3

[0079] 1. Catalyst preparation

[0080] ① Catalyst support preparation

[0081] (1) Take 15 g of dry rice husks and add them to 500 ml of a sulfuric acid solution with a concentration of 5 mol / L. Stir and heat at 80 °C for 5 h, with a stirring speed of 450 rpm. Filter, wash with water, and dry at 80 °C for 3 h to obtain support i;

[0082] (2) Take 5 g of support i and 40 g of silica microspheres and add them to 2400 ml of an aqueous solution. Stir and heat in an autoclave at 175 °C for 5 h, with a stirring speed of 450 rpm. Centrifuge the resulting liquid to obtain support ii;

[0083] (3) The carrier ii is dried in an air atmosphere at 70 °C for 72 h to obtain the catalyst carrier.

[0084] ② Catalyst preparation

[0085] (1) Take 120 ml of a solution containing chloropalladic acid and tellurous acid, where the content of palladium in the solution is 2.75 g / L and the content of tellurium is 3.0 g / L. Add 130 ml of the catalyst carrier prepared in step ①, mix evenly and impregnate for 12 h to obtain catalyst precursor I;

[0086] (2) The catalyst precursor I is reduced in a hydrogen atmosphere with a hydrogen space velocity of 120 hr -1 , a pressure of 0.5 MPa, a reduction temperature of 150 °C, and a reduction time of 4 h to obtain catalyst precursor II;

[0087] (3) The catalyst precursor II is dried at 80 °C for 2 h to obtain the finished catalyst.

[0088] The composition of the catalyst is shown in Table 1, and the infrared spectrum is similar to that of Figure 1 Example 1. The intensity ratio of peak A to peak B is about 1:1.3.

[0089] 2. Catalyst evaluation

[0090] Evaluation is carried out using a batch reactor, and the specific conditions are as follows:

[0091] Catalyst loading volume: 100 ml;

[0092] Raw material feed: Butadiene flow rate: 37.3 g / h, acetic acid flow rate: 147 g / h, air flow rate: 52 L / h;

[0093] Reaction pressure: 2.2 MPa;

[0094] Reaction temperature: 100 °C;

[0095] Reaction time: 5 h;

[0096] The contents of each component in the reaction product are analyzed by gas chromatography, and the obtained test result data are listed in Table 1.

[0097]

Example 4

[0098] 1. Catalyst preparation

[0099] ① Catalyst carrier preparation

[0100] (1) Take 15 g of dry rice husks and add them to 500 ml of a sulfuric acid solution with a concentration of 1 mol / L. Stir and heat at 80 °C for 5 h, with a stirring speed of 450 rpm. Filter, wash with water, and dry at 80 °C for 3 h to obtain carrier i;

[0101] (2) Take 5 g of carrier i and 10 g of silica microspheres and add them to 2400 ml of an aqueous solution. Stir and heat at 175 °C in an autoclave for 5 h with a stirring speed of 450 rpm. After centrifuging the resulting liquid, obtain carrier ii;

[0102] (3) Dry carrier ii in an air atmosphere at 70 °C for 72 h to obtain the catalyst carrier.

[0103] ② Catalyst preparation

[0104] (1) Take 120 ml of a solution containing chloropalladic acid and telluric acid, where the palladium content in the solution is 2.75 g / L and the tellurium content is 3.0 g / L. Add 130 ml of the catalyst carrier prepared in step ①, mix evenly and impregnate for 12 h to obtain catalyst precursor I;

[0105] (2) Reduce catalyst precursor I in a hydrogen atmosphere with a hydrogen space velocity of 120 hr -1 , a pressure of 0.5 MPa, a reduction temperature of 150 °C, and a reduction time of 4 h to obtain catalyst precursor II;

[0106] (3) Dry catalyst precursor II at 80 °C for 2 h to obtain the finished catalyst.

[0107] The composition of the catalyst is shown in Table 1, and the infrared spectrum is similar to that of Figure 1 Example 1. The intensity ratio of peak A to peak B is about 1:3.8.

[0108] 2. Catalyst evaluation

[0109] Evaluate using a batch reactor, and the specific conditions are as follows:

[0110] Catalyst filling volume: 100 ml;

[0111] Raw material feed: Butadiene flow rate: 37.3 g / h, acetic acid flow rate: 147 g / h, air flow rate: 52 L / h,;

[0112] Reaction pressure: 2.2 MPa;

[0113] Reaction temperature: 100 °C;

[0114] Reaction time: 5 h;

[0115] Analyze the content of each component in the reaction product by gas chromatography, and the obtained test result data are listed in Table 1.

[0116]

Example 5

[0117] 1. Catalyst preparation

[0118] ① Catalyst carrier preparation

[0119] (1) Take 15 g of dry rice husks and add them to 500 ml of sulfuric acid solution with a concentration of 1 mol / L. Stir and heat at 80 °C for 5 h, with a stirring speed of 450 rpm. Filter, wash with water, and dry at 80 °C for 3 h to obtain support i.

[0120] (2) Take 5 g of support i and 80 g of silica microspheres and add them to 2400 ml of aqueous solution. Stir and heat in an autoclave at 175 °C for 5 h, with a stirring speed of 450 rpm. Centrifuge the resulting liquid to obtain support ii.

[0121] (3) Dry support ii in an air atmosphere at 70 °C for 72 h to obtain the catalyst support.

[0122] ② Catalyst preparation

[0123] (1) Take 120 ml of a solution containing chloropalladic acid and tellurous acid, where the palladium content in the solution is 2.75 g / L and the tellurium content is 3.0 g / L. Add 130 ml of the catalyst support prepared in step ①, mix evenly, and impregnate for 12 h to obtain catalyst precursor I.

[0124] (2) Reduce catalyst precursor I in a hydrogen atmosphere, with a hydrogen space velocity of 120 h -1 , a pressure of 0.5 MPa, a reduction temperature of 150 °C, and a reduction time of 4 h to obtain catalyst precursor II.

[0125] (3) Dry catalyst precursor II at 80 °C for 2 h to obtain the finished catalyst.

[0126] The composition of the catalyst is shown in Table 1, and the infrared spectrum is similar to that of Figure 1 Example 1. The intensity ratio of peak A to peak B is approximately 1:0.65.

[0127] 2. Catalyst evaluation

[0128] Evaluate using a batch reactor, and the specific conditions are as follows:

[0129] Catalyst loading volume: 100 ml;

[0130] Raw material feed: Butadiene flow rate: 37.3 g / h, acetic acid flow rate: 147 g / h, air flow rate: 52 L / h;

[0131] Reaction pressure: 2.2 MPa;

[0132] Reaction temperature: 100 °C;

[0133] Reaction time: 5 h;

[0134] Analyze the content of each component in the reaction product by gas chromatography, and the obtained test result data are listed in Table 1.

[0135]

Example 6

[0136] 1. Catalyst preparation

[0137] ① Preparation of catalyst support

[0138] (1) Take 15 g of dry rice husks and add them to 500 ml of sulfuric acid solution with a concentration of 1 mol / L. Stir and heat at 80 °C for 5 h, with a stirring speed of 450 rpm. Filter, wash with water, and dry at 80 °C for 3 h to obtain support i;

[0139] (2) Take 5 g of support i and 40 g of silica microspheres and add them to 2400 ml of aqueous solution. Stir and heat in an autoclave at 150 °C for 5 h, with a stirring speed of 450 rpm. Centrifuge the resulting liquid to obtain support ii;

[0140] (3) Dry support ii in an air atmosphere at 70 °C for 72 h to obtain the catalyst support.

[0141] ② Catalyst preparation

[0142] (1) Take 120 ml of a solution containing chloropalladic acid and tellurous acid, where the palladium content in the solution is 2.75 g / L and the tellurium content is 3.0 g / L. Add 130 ml of the catalyst support prepared in step ①, mix evenly, and impregnate for 12 h to obtain catalyst precursor I;

[0143] (2) Reduce catalyst precursor I in a hydrogen atmosphere, with a hydrogen space velocity of 120 h -1 , a pressure of 0.5 MPa, a reduction temperature of 150 °C, and a reduction time of 4 h to obtain catalyst precursor II;

[0144] (3) Dry catalyst precursor II at 80 °C for 2 h to obtain the finished catalyst.

[0145] The composition of the catalyst is shown in Table 1, and the infrared spectrum is similar to that of Figure 1 Example 1. The intensity ratio of peak A to peak B is approximately 1:0.88.

[0146] 2. Catalyst evaluation

[0147] Evaluate using a batch reactor, and the specific conditions are as follows:

[0148] Catalyst loading volume: 100 ml;

[0149] Raw material feed: Butadiene flow rate: 37.3 g / h, acetic acid flow rate: 147 g / h, air flow rate: 52 L / h;

[0150] Reaction pressure: 2.2 MPa;

[0151] Reaction temperature: 100 °C;

[0152] Reaction time: 5 hr;

[0153] The contents of each component in the reaction product were analyzed by gas chromatography, and the test result data are listed in Table 1.

[0154]

Example 7

[0155] 1. Catalyst preparation

[0156] ① Preparation of catalyst support

[0157] (1) Take 15 g of dry rice husks and add them to 500 ml of sulfuric acid solution with a concentration of 1 mol / L. Stir and heat at 80 °C for 5 h, with a stirring speed of 450 rpm. Filter, wash with water, and dry at 80 °C for 3 h to obtain support i;

[0158] (2) Take 5 g of support i and 40 g of silica microspheres and add them to 2400 ml of aqueous solution. Stir and heat in an autoclave at 200 °C for 5 h, with a stirring speed of 450 rpm. Centrifuge the resulting liquid to obtain support ii;

[0159] (3) Dry support ii in an air atmosphere at 70 °C for 72 h to obtain the catalyst support.

[0160] ② Catalyst preparation

[0161] (1) Take 120 ml of a solution containing chloropalladic acid and telluric acid, where the content of palladium in the solution is 2.75 g / L and the content of tellurium is 3.0 g / L. Add 130 ml of the catalyst support prepared in step ①, mix evenly, and impregnate for 12 h to obtain catalyst precursor I;

[0162] (2) Reduce catalyst precursor I in a hydrogen atmosphere, with a hydrogen space velocity of 120 hr -1 , a pressure of 0.5 MPa, a reduction temperature of 150 °C, and a reduction time of 4 h to obtain catalyst precursor II;

[0163] (3) Dry catalyst precursor II at 80 °C for 2 h to obtain the finished catalyst.

[0164] The composition of the catalyst is shown in Table 1, and the infrared spectrum is similar to that of Figure 1 Example 1. The intensity ratio of peak A to peak B is 1:1.21.

[0165] 2. Catalyst evaluation

[0166] The evaluation was carried out in a batch reactor, and the specific conditions were as follows:

[0167] Catalyst loading volume: 100 ml;

[0168] Raw material feeding: Butadiene flow rate: 37.3 g / h, Acetic acid flow rate: 147 g / h, Air flow rate: 52 L / h;

[0169] Reaction pressure: 2.2 MPa;

[0170] Reaction temperature: 100 °C;

[0171] Reaction time: 5 h;

[0172] The contents of each component in the reaction product were analyzed by gas chromatography, and the experimental result data are listed in Table 1.

[0173]

Example 8

[0174] 1. Catalyst preparation

[0175] ① Preparation of catalyst support

[0176] (1) Take 15 g of dry rice husks and add them to 500 ml of sulfuric acid solution with a concentration of 1 mol / L. Stir and heat at 80 °C for 5 h, with a stirring speed of 450 rpm. Filter, wash with water, and dry at 80 °C for 3 h to obtain support i;

[0177] (2) Take 5 g of support i and 40 g of silica microspheres and add them to 2400 ml of aqueous solution. Stir and heat in an autoclave at 175 °C for 5 h, with a stirring speed of 450 rpm. Centrifuge the obtained liquid to obtain support ii;

[0178] (3) Dry support ii in an air atmosphere at 70 °C for 24 h to obtain the catalyst support.

[0179] ② Catalyst preparation

[0180] (1) Take 120 ml of a solution containing chloropalladic acid and telluric acid, where the content of palladium in the solution is 0.3 g / L and the content of tellurium is 0.3 g / L. Add 130 ml of the catalyst support prepared in step ①, mix evenly, and impregnate for 12 h to obtain catalyst precursor I;

[0181] (2) Reduce catalyst precursor I in a hydrogen atmosphere, with a hydrogen space velocity of 120 h -1 , a pressure of 0.5 MPa, a reduction temperature of 150 °C, and a reduction time of 4 h to obtain catalyst precursor II;

[0182] (3) Dry catalyst precursor II at 80 °C for 2 h to obtain the finished catalyst.

[0183] The composition of the catalyst is shown in Table 1, and the infrared spectrum is similar to that of Figure 1 Example 1. The intensity ratio of peak A to peak B is about 1:1.1.

[0184] 2. Catalyst evaluation

[0185] Evaluated using a batch reactor, with specific conditions as follows:

[0186] Volume of catalyst loaded: 100 ml;

[0187] Raw material feed: Flow rate of butadiene: 37.3 g / h, flow rate of acetic acid: 147 g / h, flow rate of air: 52 L / h;

[0188] Reaction pressure: 2.2 MPa;

[0189] Reaction temperature: 100 °C;

[0190] Reaction time: 5 h;

[0191] The contents of each component in the reaction product were analyzed by gas chromatography, and the experimental result data are listed in Table 1.

[0192]

Example 9

[0193] 1. Catalyst preparation

[0194] ① Preparation of catalyst support

[0195] (1) Take 15 g of dry rice husks and add them to 500 ml of sulfuric acid solution with a concentration of 1 mol / L. Stir and heat at 80 °C for 5 h, with a stirring speed of 450 rpm. Filter, wash with water, and dry at 80 °C for 3 h to obtain support i;

[0196] (2) Take 5 g of support i and 40 g of silica microspheres and add them to 2400 ml of aqueous solution. Stir and heat in an autoclave at 175 °C for 5 h, with a stirring speed of 450 rpm. Centrifuge the resulting liquid to obtain support ii;

[0197] (3) Dry support ii in an air atmosphere at 70 °C for 100 h to obtain the catalyst support.

[0198] ② Catalyst preparation

[0199] (1) Take 120 ml of a solution containing chloropalladic acid and telluric acid, where the content of palladium in the solution is 10 g / L and the content of tellurium is 10 g / L. Add 130 ml of the catalyst support prepared in step ①, mix evenly, and impregnate for 12 h to obtain catalyst precursor I;

[0200] (2) Reduce catalyst precursor I in a hydrogen atmosphere, with a hydrogen space velocity of 120 h -1 , a pressure of 0.5 MPa, a reduction temperature of 150 °C, and a reduction time of 4 h to obtain catalyst precursor II;

[0201] (3) Dry catalyst precursor II at 80 °C for 2 h to obtain the finished catalyst.

[0202] The composition of the catalyst is shown in Table 1, and the infrared spectrum is similar to that of Figure 1 Example 1. The intensity ratio of peak A to peak B is about 1:1.1.

[0203] 2. Catalyst evaluation

[0204] The evaluation was carried out in a batch reactor under the following specific conditions:

[0205] Filling volume of the catalyst: 100 ml;

[0206] Raw material feed: Flow rate of butadiene: 37.3 g / h, flow rate of acetic acid: 147 g / h, flow rate of air: 52 L / h;

[0207] Reaction pressure: 2.2 MPa;

[0208] Reaction temperature: 100 °C;

[0209] Reaction time: 5 h;

[0210] The contents of each component in the reaction product were analyzed by gas chromatography, and the test result data are listed in Table 1.

[0211]

Example 10

[0212] 1. Catalyst preparation

[0213] ① Preparation of catalyst support

[0214] (1) Take 15 g of dry rice husks and add them to 500 ml of sulfuric acid solution with a concentration of 1 mol / L. Stir and heat at 80 °C for 5 h, with a stirring speed of 450 rpm. Filter, wash with water, and dry at 80 °C for 3 h to obtain support i;

[0215] (2) Take 5 g of support i and 40 g of silica microspheres and add them to 2400 ml of aqueous solution. Stir and heat in an autoclave at 175 °C for 5 h, with a stirring speed of 450 rpm. Centrifuge the obtained liquid to obtain support ii;

[0216] (3) Dry support ii in an air atmosphere at 70 °C for 72 h to obtain the catalyst support.

[0217] ② Catalyst preparation

[0218] (1) Take 120 ml of a solution containing chloropalladic acid and stannous chloride, where the content of palladium in the solution is 2.75 g / L and the content of Sn is 3.0 g / L. Add 130 ml of the catalyst support prepared in step ①, mix evenly, and impregnate for 12 h to obtain catalyst precursor I;

[0219] (2) Reduce catalyst precursor I in a hydrogen atmosphere, with a hydrogen space velocity of 120 hr -1, the pressure is 0.5 MPa, the reduction temperature is 300 °C, and the reduction time is 4 h to obtain catalyst precursor II;

[0220] (3) The catalyst precursor II is dried at 80 °C for 2 h to obtain the finished catalyst.

[0221] The composition of the catalyst is shown in Table 1, and the infrared spectrum is similar to Figure 1 that of Example 1. The intensity ratio of peak A to peak B is about 1:1.1.

[0222] 2. Catalyst evaluation

[0223] The evaluation is carried out in a autoclave reactor, and the specific conditions are as follows:

[0224] Catalyst loading volume: 100 ml;

[0225] Raw material feed: Butadiene flow rate: 37.3 g / h, acetic acid flow rate: 147 g / h, air flow rate: 52 L / h;

[0226] Reaction pressure: 2.2 MPa;

[0227] Reaction temperature: 100 °C;

[0228] Reaction time: 5 h;

[0229] The contents of each component in the reaction product are analyzed by gas chromatography, and the obtained test result data are listed in Table 1.

[0230]

Comparative Example 1

[0231] 1. Catalyst preparation

[0232] (1) Take 120 ml of a solution containing chloropalladic acid and telluric acid, where the content of palladium in the solution is 2.75 g / L and the content of tellurium is 3.0 g / L, and add it to 130 ml of silica microspheres, mix evenly and impregnate for 12 h to obtain catalyst precursor I;

[0233] (2) The catalyst precursor I is reduced in a hydrogen atmosphere, and the hydrogen space velocity is 120 h -1 , the pressure is 0.5 MPa, the reduction temperature is 150 °C, and the reduction time is 4 h to obtain catalyst precursor II;

[0234] (3) The catalyst precursor II is dried at 80 °C for 2 h to obtain the finished catalyst.

[0235] The composition of the catalyst is shown in Table 1, and the infrared spectrum is shown in Figure 1 , as Figure 1 can be seen, this catalyst only has an absorption peak of Si-O-Si at 1062.1 cm -1 .

[0236] 2. Catalyst Evaluation

[0237] The evaluation was carried out in a batch reactor under the following specific conditions:

[0238] Filling volume of catalyst: 100 ml;

[0239] Feed of raw materials: Flow rate of butadiene: 37.3 g / h, flow rate of acetic acid: 147 g / h, flow rate of air: 52 L / h;

[0240] Reaction pressure: 2.2 MPa;

[0241] Reaction temperature: 100 °C;

[0242] Reaction time: 5 h;

[0243] The contents of each component in the reaction product were analyzed by gas chromatography, and the experimental result data are listed in Table 1.

[0244] Table 1 Catalytic performance of examples and comparative examples

[0245]

Claims

1. A catalyst for synthesizing 1,4 - diacetoxy - 2 - butene, comprising a carrier, a main active metal, and a co - active metal; The main active metal comprises Pd, and the co - active metal comprises Te and / or Sn; the carrier is silica modified with carbon quantum dots; In the infrared spectrum of the catalyst, there is a bimodal distribution in the range of 900-1400 cm -1 -1, which are the absorption peaks of Si-O-Si and Si-O-C respectively.

2. The catalyst according to claim 1, characterized in that, Based on the weight of the catalyst, the weight content of the carrier is 97.0 - 99.8%, the weight content of the main active metal is 0.1 - 1.5%, and the weight content of the co - active metal is 0.1 - 1.5%.

3. The catalyst according to claim 1, characterized in that, In the infrared spectrum of the catalyst, peak A is the absorption peak of Si-O-Si, and there is an absorption peak in the range of 1000-1100 cm -1 . Peak B is the absorption peak of Si-O-C, and there is an absorption peak in the range of 1100-1200 cm -1 . The intensity ratio of peak A to peak B is 1:0.1-10.

4. A method for preparing the catalyst according to any one of claims 1 - 3, comprising the following steps: (1) Preparation of the catalyst carrier: Dry rice husks are mixed with a strong acid solution and subjected to heat treatment to obtain carrier i; Carrier i and silica microspheres are subjected to heat treatment in an aqueous solution and dried to obtain the catalyst carrier; (2) Preparation of the catalyst: The catalyst carrier obtained in step (1) is impregnated with solution A containing the main active metal and the co - active metal to obtain catalyst precursor I; Then, through reduction and drying, the catalyst is prepared.

5. The method according to claim 4, characterized in that, In step (1), the mass ratio of the dry rice husks to the strong acid solution is 1:1 - 50; the mass ratio of carrier i to silica microspheres is 1:2 - 16.

6. The method according to claim 4, characterized in that, In step (1), the heat treatment conditions of carrier i and silica microspheres in the aqueous solution are 150 - 200 °C, the time is 2 - 12 h, carried out under stirring, and the stirring speed is 300 - 600 rpm.

7. The method according to claim 4, characterized in that, In step (2), the reduction step is carried out in a reducing atmosphere; the gas hourly space velocity in the reducing atmosphere is 60 - 600 h -1 , the pressure is 0.3 - 0.6 MPa, the reduction temperature is 100 - 300 °C, and the reduction time is 2 - 8 h.

8. Application of the catalyst according to any one of claims 1 - 3 in the reaction for synthesizing 1,4 - diacetoxy - 2 - butene.

9. The application according to claim 8, characterized in that, In the presence of the catalyst, raw materials including air, butadiene, and acetic acid react to obtain 1,4 - diacetoxy - 2 - butene; in terms of molar ratio, the raw material composition is butadiene: air: acetic acid = 1: a: b, a = 1 - 4, b = 2 - 5.

10. The application according to claim 8, characterized in that, The reaction pressure is 1.5 - 4.0 MPa; and / or, the reaction temperature is 60 - 140 °C.

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