1,4-butanediol and a method for its preparation

Abstract

The present application relates to a kind of 1,4-butanediol and its preparation method, the purity of 1,4-butanediol is ≥99.87%, without methyl-1,4-butanediol and 2-(4-hydroxybutyloxy)-tetrahydrofuran, the rest is impurity;Impurity includes tetrahydrofuran, content ≤0.05%, n-butanol, content ≤0.05%;Its preparation includes the following steps: S1, into the reactor of being equipped with one section load type catalyst, and import maleic anhydride solution and hydrogen gas and carry out one section hydrogenation reaction, obtain γ-butyrolactone solution;S2, into the reactor of being equipped with two section load type catalyst, and import γ-butyrolactone solution and hydrogen gas and carry out two section hydrogenation reaction, then after separation and purification, obtain 1,4-butanediol;The preparation of catalyst includes the following steps: to pitch and molybdenum disulfide are heat treated, obtain porous carbon / molybdenum disulfide carrier;Nickel precursor, copper precursor and hydrophobic compound are dispersed in water, obtain mixed solution;Porous carbon / molybdenum disulfide carrier is dipped in mixed solution, after aging, drying and heat reduction treatment, obtain catalyst.

Description

Technical Field

[0001] This invention belongs to the field of synthetic technology, and particularly relates to 1,4-butanediol and its preparation method. Background Technology

[0002] 1,4-Butanediol is an important organic and fine chemical raw material, widely used in pharmaceuticals, chemicals, textiles, papermaking, automobiles, and daily chemical products. It is one of the raw materials for bulk commodities such as polybutylene terephthalate (PBT), polybutylene succinate (PBS), and polyurethane resins.

[0003] Currently, there are two main industrial methods for preparing 1,4-butanediol: the acetylinyl-aldehyde method and the maleic anhydride hydrogenation method. The acetylinyl-aldehyde method involves reacting acetylene and formaldehyde to produce 1,4-butynediol, which is then further catalytically hydrogenated to generate 1,4-butanediol. This method has relatively low production costs, but calcium carbide is an energy-intensive raw material. The maleic anhydride hydrogenation method involves hydrogenating maleic anhydride and its derivatives to prepare a mixture of tetrahydrofuran, γ-butyrolactone, and 1,4-butanediol, which is then separated by distillation to obtain 1,4-butanediol. The maleic anhydride molecule contains one C=C bond and two C=O bonds. Under certain catalytic conditions, hydrogenation sequentially produces succinic anhydride, γ-butyrolactone, 1,4-butanediol, and tetrahydrofuran. The advantage of this technology is that it can simultaneously produce tetrahydrofuran, γ-butyrolactone, and 1,4-butanediol depending on the process conditions. The main disadvantages are that there are more hydrogenation byproducts, higher separation costs, and the acidic reaction system of maleic anhydride hydrogenation. Generally, acid-sensitive systems can lead to poisoning of the active center, making long-term production impossible.

[0004] Therefore, how to prepare high-purity 1,4-butanediol by targeted and highly selective hydrogenation remains an urgent problem to be solved and has significant industrial value. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides 1,4-butanediol and its preparation method. The method employs a high-strength molybdenum disulfide / porous carbon support, which avoids the loss of non-precious metal nickel and copper catalytic centers into the product under pressurized hydrogenation conditions, thus preventing a gradual decrease in catalyst activity and ensuring long-cycle production. Furthermore, the hydrophobic compound allows for rapid desorption of the hydrogenated product from the catalyst surface. The degree of hydrogenation of maleic anhydride C=C and its two C=O bonds can be controlled by adjusting the reaction pressure and temperature, thereby obtaining the target product.

[0006] The first objective of this invention is to provide a 1,4-butanediol having a purity ≥99.87%, free from methyl-1,4-butanediol and 2-(4-hydroxybutoxy)-tetrahydrofuran, with the remainder being impurities; the impurities include tetrahydrofuran, with a content ≤0.05%, and n-butanol, with a content ≤0.05%.

[0007] A second objective of this invention is to provide a method for preparing 1,4-butanediol, comprising the following steps:

[0008] S1. Maleic anhydride solution and hydrogen are introduced into a reactor containing a first-stage supported catalyst to carry out a first-stage hydrogenation reaction to obtain γ-butyrolactone solution; wherein the first-stage supported catalyst has a nickel loading of 30wt%-60wt%, a copper loading of 1wt%-5wt%, and a hydrophobic compound loading of 0.01wt%-0.2wt%.

[0009] S2. A γ-butyrolactone solution and hydrogen are introduced into a reactor containing a two-stage supported catalyst to carry out a two-stage hydrogenation reaction, and then 1,4-butanediol is obtained by separation and purification; the two-stage supported catalyst has a nickel loading of 5wt%-10wt%, a copper loading of 30wt%-60wt%, and a hydrophobic compound loading of 0.01wt%-0.2wt%.

[0010] The preparation methods of the first-stage supported catalyst and the second-stage supported catalyst include the following steps: heat-treating asphalt and molybdenum disulfide to obtain a porous carbon / molybdenum disulfide support; dispersing a nickel precursor, a copper precursor, and a hydrophobic compound in water to obtain a mixed solution; the structural formula of the hydrophobic compound is as follows: n≥6; The porous carbon / molybdenum disulfide support is impregnated in a mixed solution and then aged, dried and thermally reduced.

[0011] In one embodiment of the present invention, in S1, the mass fraction of the maleic anhydride solution is 5wt%-30wt%; the solvent of the maleic anhydride solution is selected from one or more of tetrahydrofuran, γ-butyrolactone, diethyl ether, ethyl acetate, ethyl formate and methyl acetate; preferably, the solvent of the maleic anhydride solution is selected from tetrahydrofuran and / or γ-butyrolactone.

[0012] In one embodiment of the present invention, in S1, the pressure of the hydrogenation reaction is 1 MPa-10 MPa, the temperature is 25°C-100°C, and the space velocity is 0.6 hr. -1 -6.0hr -1 The flow rate ratio of the maleic anhydride solution to hydrogen is (0.1-5):(0.1-100).

[0013] Preferably, the pressure of the hydrogenation reaction is 2MPa-5MPa and the temperature is 80℃-100℃.

[0014] In one embodiment of the present invention, in S2, the pressure of the two-stage hydrogenation reaction is 3 MPa-10 MPa, the temperature is 100°C-200°C, and the space velocity is 0.6 hr. -1 -6.0hr-1 The flow rate ratio of the maleic anhydride solution to hydrogen is (0.1-5):(0.1-100).

[0015] Preferably, the pressure of the two-stage hydrogenation reaction is 5MPa-8MPa, and the temperature is 120℃-150℃.

[0016] In one embodiment of the present invention, the mass ratio of the asphalt to molybdenum disulfide is 1:5-5:1; the molybdenum disulfide has a 5-20 layer nanosheet structure.

[0017] In one embodiment of the present invention, the heat treatment is performed by heating at 200°C-400°C for 3-8 hours in an oxygen atmosphere.

[0018] In one embodiment of the present invention, the nickel precursor is selected from one or more of nickel chloride, nickel nitrate, nickel sulfate, basic nickel carbonate, nickel acetylacetone, nickel oxalate, nickel acetate, nickel citrate, nickel hypophosphite, nickel phosphate, and nickel formate; the copper precursor is selected from one or more of copper chloride, copper nitrate, and copper sulfate.

[0019] In one embodiment of the present invention, the aging temperature is 50℃-80℃ and the time is 12h-16h; the drying temperature is 100℃-150℃ and the time is 10h-14h; the thermal reduction treatment is carried out in a hydrogen atmosphere, with the temperature increased to 160℃-200℃ at a rate of 10℃ / h-20℃ / h, and the reduction is carried out for 6h-10h.

[0020] In one embodiment of the present invention, the porous carbon / molybdenum disulfide support in the first-stage supported catalyst and the second-stage supported catalyst has a pore volume of 0.2 mL / g-0.7 mL / g, a particle size of 3 mm-5 mm, and a bulk density of 750 kg / m³. 3 -1100kg / m 3 The clusters have a length of 80nm-150nm, a width of 30nm-100nm, and a thickness of 10nm-30nm; the clusters are active centers composed of nickel, copper, and hydrophobic compounds supported on porous carbon / molybdenum disulfide supports.

[0021] The porous carbon / molybdenum disulfide support of this invention, due to the layered structure of molybdenum disulfide, allows the asphalt to extend along the layered voids during high-temperature treatment. Subsequently, under certain temperatures, processes such as dehydration and removal of organic matter result in a layered carbon structure that firmly bonds with molybdenum disulfide, creating numerous porous channels that facilitate the dispersion of active metal components. Simultaneously, this composite support structure naturally possesses high mechanical strength, easily achieving a particle strength of ≥450 N / cm, which is difficult to achieve with traditional alumina particles; the mechanical strength of commercial catalyst support alumina particles typically reaches 100 N / cm.

[0022] The technical solution of the present invention has the following advantages compared with the prior art:

[0023] (1) The supported catalyst described in this invention has a strength of over 450 N / cm, and the metal is not easily lost during the reaction process, which plays a key role in the synthesis of high-purity 1,4-butanediol.

[0024] (2) The supported catalyst of this invention uses high-strength porous carbon / molybdenum disulfide as a support. The porous carbon / molybdenum disulfide support has certain hydrogenation activity, which can promote the improvement of reaction activity, thereby reducing the reaction temperature, improving the reaction selectivity, and thus improving the product purity. In addition, it can solve the problem that under pressurized hydrogenation conditions, the non-precious metal nickel and copper catalytic centers are lost into the product, resulting in a gradual decrease in catalyst activity and making it impossible to guarantee long-cycle production.

[0025] (3) The supported catalyst described in this invention uses hydrophobic compounds as additives, which can make the product 1,4-butanediol desorb from the surface of the supported catalyst as soon as possible. On the one hand, it can accelerate the reaction rate, and on the other hand, it can avoid further reaction of the product on the catalyst surface. Furthermore, by adjusting the reaction pressure and temperature, the degree of hydrogenation of the C=C bond and the two C=O bonds in the maleic anhydride molecule can be controlled, thereby achieving the final goal of the product purity reaching the polymerization grade, and without methyl-1,4-butanediol and 2-(4-hydroxybutoxy)-tetrahydrofuran. Detailed Implementation

[0026] The present invention will be further described below with reference to specific embodiments, so that those skilled in the art can better understand and implement the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. It should be understood that the specific embodiments are only used to explain the present invention, but the embodiments are not intended to limit the present invention.

[0027] In this invention, unless otherwise stated, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0028] In this invention, unless otherwise stated, the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0029] In this invention, unless otherwise specified, the experimental methods used in the embodiments of this invention are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.

[0030] In this invention, unless otherwise stated, the molybdenum disulfide used in the embodiments of this invention is a 5-20 layer nanosheet structure.

[0031] Example 1

[0032] The 1,4-butanediol and its preparation method in this embodiment specifically include the following steps:

[0033] Preparation of S1, one-stage supported catalyst and two-stage supported catalyst

[0034] S11. Preparation of porous carbon / molybdenum disulfide carrier: Asphalt and molybdenum disulfide were mixed at a mass ratio of 1:1 and heat-treated at 300℃ for 4 hours under oxygen conditions to obtain a pore volume of 0.5 mL / g, a particle size of 5 mm, and a bulk density of 850 kg / m³. 3 Porous carbon / molybdenum disulfide support;

[0035] S12. Preparation of a first-stage mixed solution: Weigh 50.00g of basic nickel carbonate, 4.58g of copper nitrate, 159.5mL of 5mol / L dilute nitric acid solution, 0.30g of sodium dodecyl sulfonate and 500.00g of deionized water, and stir at 45℃ until all solids are dissolved to obtain a first-stage mixed solution.

[0036] S13. Preparation of the two-stage mixed solution: Weigh 9.16g of basic nickel carbonate, 50.00g of copper nitrate, 29.2mL of 5mol / L dilute nitric acid solution, 0.30g of sodium dodecyl sulfonate and 500.00g of deionized water, and stir at 45℃ until all solids are dissolved to obtain a first-stage mixed solution;

[0037] S14. Preparation of one-stage and two-stage supported catalysts: Porous carbon / molybdenum disulfide supports were impregnated in one-stage and two-stage mixed solutions, respectively. Under stirring, they were first aged at 60℃ for 14h, then dried at 120℃ for 12h, and finally packed into a tube. The temperature was increased to 200℃ for 6h under hydrogen conditions at a heating rate of 20℃ / h, and the catalysts were reduced to obtain one-stage supported catalysts with cluster length of 115nm, width of 80nm, and thickness of 23nm, and two-stage supported catalysts with cluster length of 125nm, width of 85nm, and thickness of 19nm, respectively.

[0038] Preparation of S2 and 1,4-Butanediol

[0039] S21. Preparation of maleic anhydride solution: Dissolve maleic anhydride in tetrahydrofuran to obtain a maleic anhydride solution with a mass fraction of 5 wt%.

[0040] Preparation of S22 and γ-butyrolactone solution: Maleic anhydride solution and hydrogen gas were mixed at flow rates of 0.5 mL / min and 200 mL / min, respectively, and continuously fed into a 50 mL hydrogenation tubular reactor containing a supported catalyst. The reaction temperature was 96 °C, the reaction pressure was 2.8 MPa(A), and the space velocity was 0.6 hr. -1 A γ-butyrolactone solution was obtained;

[0041] Preparation of S23 and 1,4-Butanediol: γ-Butyrolactone solution and hydrogen were mixed at flow rates of 0.5 mL / min and 200 mL / min, respectively, and continuously fed into a 50 mL hydrogenation tubular reactor containing a two-stage supported catalyst. The reaction temperature was 130 °C, the reaction pressure was 5.2 MPa, and the space velocity was 0.6 hr. -1 Then, the product is continuously fed into a distillation column for separation and purification to obtain the product.

[0042] Example 2

[0043] The process is basically the same as in Example 1, except that in the preparation of the first-stage and second-stage supported catalysts, basic nickel carbonate is replaced with nickel nitrate.

[0044] Example 3

[0045] The process is basically the same as in Example 1, except that copper nitrate is replaced with copper chloride in the preparation of the first-stage and second-stage supported catalysts.

[0046] Example 4

[0047] The process is basically the same as in Example 1, except that in the preparation of 1,4-butanediol, the 5 wt% maleic anhydride solution is replaced with a 10 wt% maleic anhydride solution.

[0048] Example 5

[0049] The process is basically the same as in Example 1, except that in the preparation of 1,4-butanediol, the solvent tetrahydrofuran in the maleic anhydride solution is replaced with the solvent γ-butyrolactone.

[0050] Comparative Example 1

[0051] The process is basically the same as in Example 1, except that copper nitrate is not added during the preparation of the first-stage and second-stage supported catalysts.

[0052] Comparative Example 2

[0053] The process is basically the same as in Example 1, except that sodium dodecyl sulfonate is not added during the preparation of the first-stage and second-stage supported catalysts.

[0054] Comparative Example 3

[0055] The process is basically the same as in Example 1, except that copper nitrate and sodium dodecyl sulfonate are not added during the preparation of the first-stage and second-stage supported catalysts.

[0056] Comparative Example 4

[0057] The process is basically the same as in Example 1, except that molybdenum disulfide is not added during the preparation of the first-stage and second-stage supported catalysts.

[0058] Test Example 1

[0059] The strength tests of the single-stage and two-stage supported catalysts of Examples 1-5 and Comparative Example 4 were conducted according to the HG / T 2782 standard, and the results are shown in Table 1:

[0060] Table 1

[0061]

[0062] As can be seen from Table 1, the strength of the supported catalyst prepared in the examples exceeds 450 N / cm. By combining high-strength molybdenum disulfide with porous carbon, the strength of the supported catalyst can be greatly improved.

[0063] Test Example 2

[0064] The purity and impurity content of the products in Examples 1-5 and Comparative Examples 1-4 were tested by gas chromatography. The gas chromatography column was an HP-5 (30m × 320μm × 0.25μm) with an FID detector. The column temperature conditions were: initial temperature 60℃, first-order termination temperature 90℃, heating rate 15℃ / min, hold for 2 min, second-order termination temperature 230℃, heating rate 10℃ / min, injection port temperature 260℃, split ratio 100:1, injection volume 0.2μL, hydrogen flow rate 30mL / min, and nitrogen flow rate 25mL / min. Standard curves were established using acetone as the solvent for maleic anhydride, succinic anhydride, tetrahydrofuran, n-butanol, γ-butyrolactone, methyl-1,4-butanediol, 2-(4-hydroxybutoxy)-tetrahydrofuran, and 1,4-butanediol. The results of maleic anhydride conversion (%) and 1,4-butanediol selectivity (%) during a continuous 1000h hydrogenation process are shown in Table 2.

[0065] Table 2

[0066]

[0067]

[0068] As can be seen from Table 2, the method of the present invention can prepare high-purity 1,4-butanediol.

[0069] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A process for the preparation of 1,4-butanediol, characterized in that, The method comprises the following steps: S1, introducing maleic anhydride solution and hydrogen into a reactor provided with a first supported catalyst to perform a first hydrogenation reaction, so as to obtain a gamma-butyrolactone solution; the first supported catalyst comprises 30wt%-60wt% of nickel, 1wt%-5wt% of copper and 0.01wt%-0.2wt% of a hydrophobic compound; S2, introducing the gamma-butyrolactone solution and hydrogen into a reactor provided with a second supported catalyst to perform a second hydrogenation reaction, and then performing separation and purification to obtain 1,4-butanediol; the second supported catalyst comprises 5wt%-10wt% of nickel, 30wt%-60wt% of copper and 0.01wt%-0.2wt% of a hydrophobic compound; The preparation method of the first supported catalyst and the second supported catalyst comprises the following steps: heat treating pitch and molybdenum disulfide to obtain a porous carbon / molybdenum disulfide carrier. A nickel precursor, a copper precursor and a hydrophobic compound are dispersed in water to obtain a mixed solution; the hydrophobic compound has a structural formula of , n≥6; and a porous carbon / molybdenum disulfide carrier is immersed in the mixed solution, and then subjected to aging, drying and thermal reduction treatment.

2. The method of preparing 1,4-butanediol according to claim 1, characterized in that, In S1, the mass fraction of the maleic anhydride solution is 5wt%-30wt%; the solvent of the maleic anhydride solution is selected from one or more of tetrahydrofuran, gamma-butyrolactone, diethyl ether, ethyl acetate, ethyl formate and methyl acetate.

3. The method for preparing 1,4-butanediol according to claim 1, characterized in that, In S1, the pressure of the one-stage hydrogenation reaction is 1-10 MPa, the temperature is 25-100°C, the space velocity is 0.6-6.0 hr -1 -6.0 hr -1 ; and the flow rate ratio of the maleic anhydride solution to hydrogen is (0.1-5):(0.1-100).

4. The method of claim 1, wherein the 1,4-butanediol is produced in a yield of at least 90%. In S2, the pressure of the two-stage hydrogenation reaction is 3-10 MPa, the temperature is 100-200°C, the space velocity is 0.6-6.0 hr -1 -6.0 hr -1 ; the flow rate ratio of the maleic anhydride solution and hydrogen is (0.1-5):(0.1-100).

5. The method of claim 1, wherein the 1,4-butanediol is produced in a yield of at least 90%. The mass ratio of the pitch to the molybdenum disulfide is 1:5-5:1; the molybdenum disulfide has a 5-20-layer nanosheet structure.

6. The method of claim 1, wherein the 1,4-butanediol is produced in a yield of at least 90%. The heat treatment is performed at 200℃-400℃ for 3h-8h in an oxygen atmosphere.

7. The method of claim 1, wherein the 1,4-butanediol is produced in a yield of at least 90%. The nickel precursor is selected from one or more of nickel chloride, nickel nitrate, nickel sulfate, basic nickel carbonate, nickel acetylacetate, nickel oxalate, nickel acetate, nickel citrate, nickel hypophosphite, nickel phosphate and nickel formate; the copper precursor is selected from one or more of copper chloride, copper nitrate and copper sulfate.

8. The method of claim 1, wherein the 1,4-butanediol is produced in a yield of at least 90%. The aging temperature is 50℃-80℃, and the aging time is 12h-16h; the drying temperature is 100℃-150℃, and the drying time is 10h-14h; the heat reduction treatment is performed at a rate of 10℃ / h-20℃ / h to 160℃-200℃ in a hydrogen atmosphere, and the reduction time is 6h-10h.

9. The method of claim 1, wherein the 1,4-butanediol is produced in a yield of at least 90%. The porous carbon / molybdenum disulfide carrier in the first-stage supported catalyst and the second-stage supported catalyst has a pore volume of 0.2 mL / g-0.7 mL / g, a particle size of 3 mm-5 mm, and a bulk density of 750 kg / m 3 -1100 kg / m 3 ; the length of the cluster is 80 nm-150 nm, the width is 30 nm-100 nm, and the thickness is 10 nm-30 nm.

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