Synthetic method of 1,4-diacetoxy-2-butene

Abstract

This invention discloses a method for synthesizing 1,4-diacetoxy-2-butene. The method comprises reacting a starting material including air, butadiene, and acetic acid in the presence of a catalyst and a reaction accelerant to obtain 1,4-diacetoxy-2-butene; wherein the reaction accelerant is one or more crown ethers and their derivatives. The method provided by this invention features high selectivity for 1,4-diacetoxy-2-butene and few byproducts.

Description

Technical Field

[0001] This invention relates to a method for synthesizing 1,4-diacetoxy-2-butene. Background Technology

[0002] 1,4-Butanediol is an organic and fine chemical raw material widely used in the production of engineering plastics and fibers, such as PBT, elastic fibers, tetrahydrofuran, polytetramethylene glycol ether, and solvents. It is also used in the production of N-methylpyrrolidone, adipic acid, acetal, and maleic anhydride. It is used as an intermediate in the production of pharmaceuticals and pesticides, as well as in coating resin softeners and crosslinking agents. China's total 1,4-butanediol (BDO) production capacity has reached approximately 504,000 tons per year, accounting for about 25.3% of the world's total production capacity. BDO products are mainly used in the production of PBT, THF, GBL, and PU. Currently, most Chinese BDO manufacturers are building downstream production facilities for tetrahydrofuran (THF), polytetrahydrofuran (PTMEG), polybutylene terephthalate (PBT), γ-butyrolactone (GBL), and methylpyrrolidone (NMP), extending upstream and expanding downstream to achieve integrated BDO industry chain and enhance market competitiveness. For BDO manufacturers, developing and exploring new areas is the best way to seize market share. In recent years, new extended products such as polybutylene succinate (PBS) and thermoplastic polyester elastomer (TPEE) have become hot topics in the industry. The production capacity of these products in China is relatively small, indicating good market potential in the future. Currently, the main global BDO production processes include the Reppe process (acetylene aldehyde process), maleic anhydride process, propylene oxide process (allyl alcohol process), and butadiene process.

[0003] China currently has an overcapacity in butadiene production, while the BDO market is rapidly developing. In regions rich in butadiene, the production of BDO from butadiene offers significant advantages in terms of raw materials and price. The key technical step in the butadiene-to-1,4-butanediol route is the oxyacylation of butadiene to generate 1,4-diacetoxy-2-butene. The main byproduct of this step is 3,4-diacetoxy-1-butene; therefore, improving the selectivity of this reaction can significantly enhance the economic benefits of this technical route. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that the prior art synthesis method of 1,4-diacetoxy-2-butene has low selectivity. The present invention provides a synthesis method of 1,4-diacetoxy-2-butene with high selectivity and few by-products.

[0005] The present invention provides a method for synthesizing 1,4-diacetoxy-2-butene, wherein the method comprises: reacting a raw material including air, butadiene and acetic acid in the presence of a catalyst and a reaction aid to obtain 1,4-diacetoxy-2-butene;

[0006] The reaction aid is one or more of crown ethers and their derivatives.

[0007] Furthermore, the reaction aid has a mass content of 0.1% to 5% in acetic acid, for example, but not limited to 0.2%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, and 4.5%.

[0008] Further, the composition of the raw material, in molar ratio, is butadiene:air:acetic acid = 1:a:b, where a = 1 to 4 and b = 2 to 5; and / or, the reaction pressure is 1.5 to 4.0 MPa; and / or, the reaction temperature is 60 to 140 °C.

[0009] Furthermore, the reaction aid is one or more compounds selected from the compounds shown in the following structural formulas.

[0010]

[0011] In the reaction aids, R1 and R2 are each independently selected from 1,2-ethylene, o-diphenyl, and o-dicyclohexyl; n is an integer from 1 to 6.

[0012] The reaction aid is selected from one or more of 18-crown ether-6, 15-crown ether-5, dicyclohexano-18-crown ether-6, benzo-18-crown ether-6, and dibenzo-18-crown ether-6, preferably 18-crown ether-6 and 15-crown ether-5.

[0013] Furthermore, the catalyst includes a support, a main catalytic metal, and a co-catalytic metal; wherein the main catalytic metal includes Pd, and the co-catalytic metal includes Te and / or Sn.

[0014] Furthermore, in the catalyst, the mass content of the support is 97.0% to 99.4%, the mass content of the main catalytic metal is 0.3% to 1.5%, and the mass content of the co-catalytic metal is 0.3% to 1.5%.

[0015] Furthermore, the catalyst can be obtained by the following preparation method, specifically including the following steps:

[0016] (1) Take a solution containing the main catalytic metal and the co-catalytic metal, mix them to obtain an impregnation solution, add it to activated carbon, mix and impregnate, dry it to obtain catalyst precursor I;

[0017] (2) Catalyst precursor I is reduced in a reducing agent to obtain catalyst precursor II;

[0018] (3) The catalyst precursor II was dried to obtain the finished catalyst.

[0019] Further, in step (1), the content of the main catalytic metal in the solution is 0.3 to 10 g / L, for example, but not limited to 0.5 g / L, 1.0 g / L, 1.5 g / L, 2.0 g / L, 2.5 g / L, 3.0 g / L, 3.5 g / L, 4.0 g / L, 4.5 g / L, 5.0 g / L, 5.5 g / L, 6.0 g / L, 6.5 g / L, 7.0 g / L, 7.5 g / L, 8.0 g / L, 8.5 g / L, 9.0 g / L, and 9.5 g / L.

[0020] Further, in step (1), the content of the co-catalytic metal is 0.3 to 10 g / L, for example, but not limited to 0.5 g / L, 1.0 g / L, 1.5 g / L, 2.0 g / L, 2.5 g / L, 3.0 g / L, 3.5 g / L, 4.0 g / L, 4.5 g / L, 5.0 g / L, 5.5 g / L, 6.0 g / L, 6.5 g / L, 7.0 g / L, 7.5 g / L, 8.0 g / L, 8.5 g / L, 9.0 g / L, and 9.5 g / L.

[0021] Furthermore, in step (1), the volume ratio of the amount of activated carbon added to the impregnation solution is 0.8 to 1.2.

[0022] Furthermore, in step (1), before drying, the solid is usually obtained by separation and filtration, and then dried. The drying conditions are drying at 60-100°C for 4-36 hours.

[0023] Furthermore, in step (2), the reducing agent is selected from reducing gases, such as hydrogen. The reduction process, using hydrogen as an example, involves reducing catalyst precursor I in a hydrogen atmosphere.

[0024] Furthermore, in step (2), the gas space velocity of the reducing gas is 60–300 hr. -1 The pressure is 0.2–0.8 MPa, the reduction temperature is 100–300℃, and the reduction time is 2–6 h.

[0025] Further, in step (3), the drying conditions are: drying at 60-80°C for 1-4 hours.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] The method for synthesizing 1,4-diacetoxy-2-butene provided by the present invention improves the selectivity of 1,4-diacetoxy-2-butene by adding crown ethers or crown ether derivatives to the reaction system. It is speculated that the addition of the above-mentioned auxiliaries can selectively promote the oxyacylation reaction to occur more at the 1,4-C position of 1,3-butadiene than at the 1,2-C position. Detailed Implementation

[0028] The present invention will now be described in detail with reference to specific embodiments. These embodiments are for illustrative purposes only and do not constitute any limitation thereof. The invention has been described with reference to exemplary embodiments, but it should be understood that the terms used are descriptive and explanatory, not limiting. Modifications and revisions can be made to the invention within the scope of the claims as specified herein, without departing from the scope and spirit of the invention. Although the invention described herein relates to specific methods, materials, and embodiments, it does not imply that the invention is limited to the specific examples disclosed herein; on the contrary, the invention can be extended to all other methods and applications with the same function.

[0029] In this invention, the fraction of active components in the catalyst is obtained by XRF (X-ray fluorescence spectrometry). The characterization method is as follows: a certain amount of catalyst is ground into powder of 60-100 mesh in a ball mill, and the powder is placed in the XRF sample cell for analysis. The content of each element in the catalyst can be obtained by comparing it with the measured standard curve.

[0030] In this invention, the yield of 1,4-diacetoxy-2-butene refers to the amount of product obtained per hour, which is the mass of crude product obtained per hour multiplied by the content of the target product in the crude product.

[0031] In this invention, the molar quantity of air, one of the raw materials used, is calculated according to the ideal gas law, assuming that the average molecular weight of air is 29.

[0032]

Example 1

[0033] 1. Catalyst Preparation

[0034] (1) Take 120 ml of a solution containing chloropalladic acid and telluric acid, wherein the palladium content in the solution is 2.75 g / L and the tellurium content is 3.0 g / L, add it to 130 ml of activated carbon with a mesh size of 20-40, mix evenly and impregnate for 12 h, filter to obtain a solid, and dry at 80 °C for 8 h to obtain catalyst precursor I;

[0035] (2) Catalyst precursor I was reduced in a hydrogen atmosphere with a hydrogen space velocity of 120 hr. -1 The catalyst precursor II was obtained by applying a pressure of 0.5 MPa, a reduction temperature of 150 °C, and a reduction time of 4 h.

[0036] (3) The catalyst precursor II was dried at 80°C for 2 hours to obtain the finished catalyst. The mass fraction of Pd in ​​the catalyst was 0.63%, the mass fraction of Te was 0.68%, and the mass fraction of the support was 98.69%.

[0037] 2. Catalyst Evaluation

[0038] The evaluation was conducted using a batch reactor, under the following conditions:

[0039] Catalyst loading volume: 50g;

[0040] Raw material feed: butadiene flow rate: 37.3 g / h, acetic acid flow rate: 147 g / h, air flow rate: 52 L / h, acetic acid contains 1.0% 18-crown-6 ether by mass.

[0041] Reaction pressure: 2.2 MPa;

[0042] Reaction temperature: 100℃;

[0043] Reaction time: 5 hours;

[0044] The content of each component in the reaction product was analyzed by gas chromatography, and then the yield of the catalyst was calculated. The experimental data obtained are listed in Table 1.

[0045]

Example 2

[0046] 1. Catalyst Preparation

[0047] (1) Take 120 ml of a solution containing chloropalladic acid and telluric acid, wherein the palladium content in the solution is 2.75 g / L and the tellurium content is 3.0 g / L, add it to 130 ml of activated carbon with a mesh size of 20-40, mix evenly and impregnate for 12 h, filter to obtain a solid, and dry at 80 °C for 8 h to obtain catalyst precursor I;

[0048] (2) Catalyst precursor I was reduced in a hydrogen atmosphere with a hydrogen space velocity of 120 hr. -1 The catalyst precursor II was obtained by applying a pressure of 0.5 MPa, a reduction temperature of 150 °C, and a reduction time of 4 h.

[0049] (3) The catalyst precursor II was dried at 80°C for 2 hours to obtain the finished catalyst. The mass fraction of Pd in ​​the catalyst was 0.63%, the mass fraction of Te was 0.68%, and the mass fraction of the support was 98.69%.

[0050] 2. Catalyst Evaluation

[0051] The evaluation was conducted using a batch reactor, under the following conditions:

[0052] Catalyst loading volume: 50g;

[0053] Raw material feed: butadiene flow rate: 37.3 g / h, acetic acid flow rate: 147 g / h, air flow rate: 52 L / h, acetic acid contains 0.1% 18-crown-6 ether by mass;

[0054] Reaction pressure: 2.2 MPa;

[0055] Reaction temperature: 100℃;

[0056] Reaction time: 5 hours;

[0057] The content of each component in the reaction product was analyzed by gas chromatography, and then the yield of the catalyst was calculated. The experimental data obtained are listed in Table 1.

[0058]

Example 3

[0059] 1. Catalyst Preparation

[0060] (1) Take 120 ml of a solution containing chloropalladic acid and telluric acid, wherein the palladium content in the solution is 2.75 g / L and the tellurium content is 3.0 g / L, add it to 130 ml of activated carbon with a mesh size of 20-40, mix evenly and impregnate for 12 h, filter to obtain a solid, and dry at 80 °C for 8 h to obtain catalyst precursor I;

[0061] (2) Catalyst precursor I was reduced in a hydrogen atmosphere with a hydrogen space velocity of 120 hr. -1 The catalyst precursor II was obtained by applying a pressure of 0.5 MPa, a reduction temperature of 150 °C, and a reduction time of 4 h.

[0062] (3) The catalyst precursor II was dried at 80°C for 2 hours to obtain the finished catalyst. The mass fraction of Pd in ​​the catalyst was 0.63%, the mass fraction of Te was 0.68%, and the mass fraction of the support was 98.69%.

[0063] 2. Catalyst Evaluation

[0064] The evaluation was conducted using a batch reactor, under the following conditions:

[0065] Catalyst loading volume: 50g;

[0066] Raw material feed: butadiene flow rate: 37.3 g / h, acetic acid flow rate: 147 g / h, air flow rate: 52 L / h, acetic acid contains 5.0% 18-crown-6 ether by mass.

[0067] Reaction pressure: 2.2 MPa;

[0068] Reaction temperature: 100℃;

[0069] Reaction time: 5 hours;

[0070] The content of each component in the reaction product was analyzed by gas chromatography, and then the yield of the catalyst was calculated. The experimental data obtained are listed in Table 1.

[0071]

Example 4

[0072] 1. Catalyst Preparation

[0073] (1) Take 120 ml of a solution containing chloropalladic acid and telluric acid, wherein the palladium content in the solution is 2.75 g / L and the tellurium content is 3.0 g / L, add it to 130 ml of activated carbon with a mesh size of 20-40, mix evenly and impregnate for 12 h, filter to obtain a solid, and dry at 80 °C for 8 h to obtain catalyst precursor I;

[0074] (2) Catalyst precursor I was reduced in a hydrogen atmosphere with a hydrogen space velocity of 120 hr. -1 The catalyst precursor II was obtained by applying a pressure of 0.5 MPa, a reduction temperature of 150 °C, and a reduction time of 4 h.

[0075] (3) The catalyst precursor II was dried at 80°C for 2 hours to obtain the finished catalyst. The mass fraction of Pd in ​​the catalyst was 0.63%, the mass fraction of Te was 0.68%, and the mass fraction of the support was 98.69%.

[0076] 2. Catalyst Evaluation

[0077] The evaluation was conducted using a batch reactor, under the following conditions:

[0078] Catalyst loading volume: 50g;

[0079] Raw material feed: butadiene flow rate: 37.3 g / h, acetic acid flow rate: 147 g / h, air flow rate: 52 L / h, acetic acid contains 1.0% 15-crown ether-5 by mass;

[0080] Reaction pressure: 2.2 MPa;

[0081] Reaction temperature: 100℃;

[0082] Reaction time: 5 hours;

[0083] The content of each component in the reaction product was analyzed by gas chromatography, and then the yield of the catalyst was calculated. The experimental data obtained are listed in Table 1.

[0084]

Example 5

[0085] 1. Catalyst Preparation

[0086] (1) Take 120 ml of a solution containing chloropalladic acid and telluric acid, wherein the palladium content in the solution is 2.75 g / L and the tellurium content is 3.0 g / L, add it to 130 ml of activated carbon with a mesh size of 20-40, mix evenly and impregnate for 12 h, filter to obtain a solid, and dry at 80 °C for 8 h to obtain catalyst precursor I;

[0087] (2) Catalyst precursor I was reduced in a hydrogen atmosphere with a hydrogen space velocity of 120 hr. -1 The catalyst precursor II was obtained by applying a pressure of 0.5 MPa, a reduction temperature of 150 °C, and a reduction time of 4 h.

[0088] (3) The catalyst precursor II was dried at 80°C for 2 hours to obtain the finished catalyst. The mass fraction of Pd in ​​the catalyst was 0.63%, the mass fraction of Te was 0.68%, and the mass fraction of the support was 98.69%.

[0089] 2. Catalyst Evaluation

[0090] The evaluation was conducted using a batch reactor, under the following conditions:

[0091] Catalyst loading volume: 50g;

[0092] Feed materials: Butadiene flow rate: 37.3 g / h, acetic acid flow rate: 147 g / h, air flow rate: 52 L / h, acetic acid contains 1.0% dicyclohexano-18-crown ether-6 by mass;

[0093] Reaction pressure: 2.2 MPa;

[0094] Reaction temperature: 100℃;

[0095] Reaction time: 5 hours;

[0096] The content of each component in the reaction product was analyzed by gas chromatography, and then the yield of the catalyst was calculated. The experimental data obtained are listed in Table 1.

[0097]

Example 6

[0098] 1. Catalyst Preparation

[0099] (1) Take 120 ml of a solution containing chloropalladic acid and telluric acid, wherein the palladium content in the solution is 2.75 g / L and the tellurium content is 3.0 g / L, add it to 130 ml of activated carbon with a mesh size of 20-40, mix evenly and impregnate for 12 h, filter to obtain a solid, and dry at 80 °C for 8 h to obtain catalyst precursor I;

[0100] (2) Catalyst precursor I was reduced in a hydrogen atmosphere with a hydrogen space velocity of 120 hr. -1The catalyst precursor II was obtained by applying a pressure of 0.5 MPa, a reduction temperature of 150 °C, and a reduction time of 4 h.

[0101] (3) The catalyst precursor II was dried at 80°C for 2 hours to obtain the finished catalyst. The mass fraction of Pd in ​​the catalyst was 0.63%, the mass fraction of Te was 0.68%, and the mass fraction of the support was 98.69%.

[0102] 2. Catalyst Evaluation

[0103] The evaluation was conducted using a batch reactor, under the following conditions:

[0104] Catalyst loading volume: 50g;

[0105] Feed materials: Butadiene flow rate: 37.3 g / h, acetic acid flow rate: 147 g / h, air flow rate: 52 L / h, benzo-18-crown-6 content in acetic acid: 1.0% by mass;

[0106] Reaction pressure: 2.2 MPa;

[0107] Reaction temperature: 100℃;

[0108] Reaction time: 5 hours;

[0109] The content of each component in the reaction product was analyzed by gas chromatography, and then the yield of the catalyst was calculated. The experimental data obtained are listed in Table 1.

[0110]

Example 7

[0111] 1. Catalyst Preparation

[0112] (1) Take 120 ml of a solution containing chloropalladic acid and telluric acid, wherein the palladium content in the solution is 2.75 g / L and the tellurium content is 3.0 g / L, add it to 130 ml of activated carbon with a mesh size of 20-40, mix evenly and impregnate for 12 h, filter to obtain a solid, and dry at 80 °C for 8 h to obtain catalyst precursor I;

[0113] (2) Catalyst precursor I was reduced in a hydrogen atmosphere with a hydrogen space velocity of 120 hr. -1 The catalyst precursor II was obtained by applying a pressure of 0.5 MPa, a reduction temperature of 150 °C, and a reduction time of 4 h.

[0114] (3) The catalyst precursor II was dried at 80°C for 2 hours to obtain the finished catalyst. The mass fraction of Pd in ​​the catalyst was 0.63%, the mass fraction of Te was 0.68%, and the mass fraction of the support was 98.69%.

[0115] 2. Catalyst Evaluation

[0116] The evaluation was conducted using a batch reactor, under the following conditions:

[0117] Catalyst loading volume: 50g;

[0118] Feed materials: Butadiene flow rate: 37.3 g / h, acetic acid flow rate: 147 g / h, air flow rate: 52 L / h, acetic acid contains 1.0% dibenzo-18-crown ether-6 by mass;

[0119] Reaction pressure: 2.2 MPa;

[0120] Reaction temperature: 100℃;

[0121] Reaction time: 5 hours;

[0122] The content of each component in the reaction product was analyzed by gas chromatography, and then the yield of the catalyst was calculated. The experimental data obtained are listed in Table 1.

[0123]

Example 8

[0124] 1. Catalyst Preparation

[0125] (1) Take 120 ml of a solution containing chloropalladic acid and telluric acid, wherein the palladium content in the solution is 2.75 g / L and the tellurium content is 3.0 g / L, add it to 130 ml of activated carbon with a mesh size of 20-40, mix evenly and impregnate for 12 h, filter to obtain a solid, and dry at 80 °C for 8 h to obtain catalyst precursor I;

[0126] (2) Catalyst precursor I was reduced in a hydrogen atmosphere with a hydrogen space velocity of 120 hr. -1 The catalyst precursor II was obtained by applying a pressure of 0.5 MPa, a reduction temperature of 150 °C, and a reduction time of 4 h.

[0127] (3) The catalyst precursor II was dried at 80°C for 2 hours to obtain the finished catalyst. The mass fraction of Pd in ​​the catalyst was 0.63%, the mass fraction of Te was 0.68%, and the mass fraction of the support was 98.69%.

[0128] 2. Catalyst Evaluation

[0129] The evaluation was conducted using a batch reactor, under the following conditions:

[0130] Catalyst loading volume: 50g;

[0131] Raw material feed: butadiene flow rate: 37.3 g / h, acetic acid flow rate: 147 g / h, air flow rate: 52 L / h, acetic acid contains 0.5% 18-crown ether-6 and 0.5% 15-crown ether-5 by mass;

[0132] Reaction pressure: 2.2 MPa;

[0133] Reaction temperature: 100℃;

[0134] Reaction time: 5 hours;

[0135] The content of each component in the reaction product was analyzed by gas chromatography, and then the yield of the catalyst was calculated. The experimental data obtained are listed in Table 1.

[0136]

Example 9

[0137] 1. Catalyst Preparation

[0138] (1) Take 120 ml of a solution containing chloropalladic acid and tin chloride, wherein the palladium content in the solution is 2.75 g / L and the Sn content is 2.8 g / L, add it to 130 ml of activated carbon with a mesh size of 20-40, mix evenly and impregnate for 12 h, filter to obtain a solid, and dry at 80 °C for 8 h to obtain catalyst precursor I;

[0139] (2) Catalyst precursor I was reduced in a hydrogen atmosphere with a hydrogen space velocity of 120 hr. -1 The catalyst precursor II was obtained by applying a pressure of 0.5 MPa, a reduction temperature of 150 °C, and a reduction time of 4 h.

[0140] (3) The catalyst precursor II was dried at 80°C for 2 hours to obtain the finished catalyst. The mass fraction of Pd in ​​the catalyst was 0.63%, the mass fraction of Sn was 0.63%, and the mass fraction of the support was 98.84%.

[0141] 2. Catalyst Evaluation

[0142] The evaluation was conducted using a batch reactor, under the following conditions:

[0143] Catalyst loading volume: 50g;

[0144] Raw material feed: butadiene flow rate: 37.3 g / h, acetic acid flow rate: 147 g / h, air flow rate: 52 L / h, acetic acid contains 1.0% 18-crown-6 ether by mass.

[0145] Reaction pressure: 2.2 MPa;

[0146] Reaction temperature: 100℃;

[0147] Reaction time: 5 hours;

[0148] The content of each component in the reaction product was analyzed by gas chromatography, and then the yield of the catalyst was calculated. The experimental data obtained are listed in Table 1.

[0149]

Example 10

[0150] 1. Catalyst Preparation

[0151] (1) Take 120 ml of a solution containing chloropalladic acid and telluric acid, wherein the palladium content in the solution is 2.75 g / L and the tellurium content is 3.0 g / L, add it to 130 ml of activated carbon with a mesh size of 20-40, mix evenly and impregnate for 12 h, filter to obtain a solid, and dry at 80 °C for 8 h to obtain catalyst precursor I;

[0152] (2) Catalyst precursor I was reduced in a hydrogen atmosphere with a hydrogen space velocity of 120 hr. -1 The catalyst precursor II was obtained by applying a pressure of 0.5 MPa, a reduction temperature of 150 °C, and a reduction time of 4 h.

[0153] (3) The catalyst precursor II was dried at 80°C for 2 hours to obtain the finished catalyst. The mass fraction of Pd in ​​the catalyst was 0.63%, the mass fraction of Te was 0.68%, and the mass fraction of the support was 98.69%.

[0154] 2. Catalyst Evaluation

[0155] The evaluation was conducted using a batch reactor, under the following conditions:

[0156] Catalyst loading volume: 50g;

[0157] Raw material feed: butadiene flow rate: 37.3 g / h, acetic acid flow rate: 147 g / h, air flow rate: 52 L / h, acetic acid contains 1.0% 18-crown-6 ether by mass.

[0158] Reaction pressure: 3.0 MPa;

[0159] Reaction temperature: 120℃;

[0160] Reaction time: 5 hours;

[0161] The content of each component in the reaction product was analyzed by gas chromatography, and then the yield of the catalyst was calculated. The experimental data obtained are listed in Table 1.

[0162]

Example 11

[0163] 1. Catalyst Preparation

[0164] (1) Take 120 ml of a solution containing chloropalladic acid and telluric acid, wherein the palladium content in the solution is 2.75 g / L and the tellurium content is 3.0 g / L, add it to 130 ml of activated carbon with a mesh size of 20-40, mix evenly and impregnate for 12 h, filter to obtain a solid, and dry at 80 °C for 8 h to obtain catalyst precursor I;

[0165] (2) Catalyst precursor I was reduced in a hydrogen atmosphere with a hydrogen space velocity of 120 hr. -1The catalyst precursor II was obtained by applying a pressure of 0.5 MPa, a reduction temperature of 150 °C, and a reduction time of 4 h.

[0166] (3) The catalyst precursor II was dried at 80°C for 2 hours to obtain the finished catalyst. The mass fraction of Pd in ​​the catalyst was 0.63%, the mass fraction of Te was 0.68%, and the mass fraction of the support was 98.69%.

[0167] 2. Catalyst Evaluation

[0168] The evaluation was conducted using a batch reactor, under the following conditions:

[0169] Catalyst loading volume: 50g;

[0170] Raw material feed: butadiene flow rate: 37.3 g / h, acetic acid flow rate: 147 g / h, air flow rate: 52 L / h, acetic acid contains 1.0% 18-crown-6 ether by mass.

[0171] Reaction pressure: 2.0 MPa;

[0172] Reaction temperature: 80℃;

[0173] Reaction time: 5 hours;

[0174] The content of each component in the reaction product was analyzed by gas chromatography, and then the yield of the catalyst was calculated. The experimental data obtained are listed in Table 1.

[0175] Comparative Example 1

[0176] 1. Catalyst Preparation

[0177] (1) Take 120 ml of a solution containing chloropalladic acid and telluric acid, wherein the palladium content in the solution is 2.75 g / L and the tellurium content is 3.0 g / L, add it to 130 ml of activated carbon with a mesh size of 20-40, mix evenly and impregnate for 12 h, filter to obtain a solid, and dry at 80 °C for 8 h to obtain catalyst precursor I;

[0178] (2) Catalyst precursor I was reduced in a hydrogen atmosphere with a hydrogen space velocity of 120 hr. -1 The catalyst precursor II was obtained by applying a pressure of 0.5 MPa, a reduction temperature of 150 °C, and a reduction time of 4 h.

[0179] (3) The catalyst precursor II was dried at 80°C for 2 hours to obtain the finished catalyst. The mass fraction of Pd in ​​the catalyst was 0.63%, the mass fraction of Te was 0.68%, and the mass fraction of the support was 98.69%.

[0180] 2. Catalyst Evaluation

[0181] The evaluation was conducted using a batch reactor, under the following conditions:

[0182] Catalyst loading volume: 50g;

[0183] Raw material feed: Butadiene flow rate: 37.3 g / h, acetic acid flow rate: 147 g / h, air flow rate: 52 L / h;

[0184] Reaction pressure: 2.2 MPa;

[0185] Reaction temperature: 100℃;

[0186] Reaction time: 5 hours;

[0187] The content of each component in the reaction product was analyzed by gas chromatography, and then the yield of the catalyst was calculated. The experimental data obtained are listed in Table 1.

[0188] Table 1 Catalytic performance of the examples and comparative examples

[0189]

Claims

1. A method for the synthesis of 1,4-diacetoxy-2-butene, wherein, The synthesis method comprises: raw materials including air, butadiene and acetic acid are reacted in the presence of a catalyst and a reaction aid to obtain 1,4-diacetyloxy-2-butene; The reaction aid is one or more of 18-crown-6, 15-crown-5, bicyclohexano-18-crown-6, benzo-18-crown-6 and dibenzo-18-crown-6. The catalyst comprises a carrier, a main catalytic metal and an auxiliary catalytic metal, wherein the main catalytic metal comprises Pd, and the auxiliary catalytic metal comprises Te and / or Sn.

2. The method of synthesis of claim 1, wherein, The mass content of the reaction aid in the acetic acid is 0.1-5%.

3. The method of synthesis of claim 1, wherein, The raw materials are composed of butadiene in terms of molar ratio: The air: acetic acid = 1: a: b, wherein a = 1-4 and b = 2-5; and / or the reaction pressure is 1.5-4.0 MPa; and / or the reaction temperature is 60-140 ℃.

4. The method of synthesis of claim 1, wherein, In the catalyst, the mass content of the carrier is 97.0-99.4%, the mass content of the main catalytic metal is 0.3-1.5%, and the mass content of the auxiliary catalytic metal is 0.3-1.5%.

5. The method of synthesis of claim 1, wherein, The catalyst is prepared by the following method, which specifically comprises the following steps: (1) A solution containing a main catalytic metal and an auxiliary catalytic metal is mixed to obtain an impregnation solution, which is added to activated carbon, mixed, impregnated and dried to obtain a catalyst precursor I; (2) The catalyst precursor I is reduced in a reducing agent to obtain a catalyst precursor II; (3) The catalyst precursor II is dried to obtain a finished catalyst.

6. The method of synthesis of claim 5, wherein, In step (1), the volume ratio of the addition amount of activated carbon to the impregnation solution is 0.8-1.

2.

7. The method of synthesis of claim 5, wherein, In step (2), the reducing agent is selected from a reducing gas, wherein the gas space velocity is 60-300 hr -1 , the pressure is 0.2-0.8 MPa, the reduction temperature is 100-300℃, and the reduction time is 2-6 h.

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