1, 4-butanediol and preparation method thereof

Abstract

The invention relates to 1, 4-butanediol and a preparation method thereof, the purity of the 1, 4-butanediol is greater than or equal to 99.87%, the 1, 4-butanediol does not contain methyl-1, 4-butanediol and 2-(4-hydroxybutoxy)-tetrahydrofuran, and the balance is impurities; the impurities comprise less than or equal to 0.05% of tetrahydrofuran and less than or equal to 0.05% of n-butyl alcohol; the preparation method comprises the following steps: S1, introducing a maleic anhydride solution and hydrogen into a reactor filled with a first-stage supported catalyst, and carrying out a first-stage hydrogenation reaction to obtain a gamma-butyrolactone solution; s2, a gamma-butyrolactone solution and hydrogen are introduced into the reactor filled with the second-stage supported catalyst for a second-stage hydrogenation reaction, and then 1, 4-butanediol is obtained through separation and purification; the preparation method of the catalyst comprises the following steps: carrying out heat treatment on asphalt and molybdenum disulfide to obtain a porous carbon / molybdenum disulfide carrier; the preparation method comprises the following steps: dispersing a nickel precursor, a copper precursor and a hydrophobic compound in water to obtain a mixed solution; and dipping the porous carbon / molybdenum disulfide carrier in the mixed solution, and carrying out aging, drying and thermal reduction treatment to obtain the catalyst.

Description

Technical Field

[0001] The invention belongs to the field of synthesis technology, and in particular relates to 1,4-butanediol and a preparation method thereof. Background Art

[0002] 1,4-Butanediol is an important organic and fine chemical raw material, widely used in medicine, chemical industry, textile, papermaking, automobile and daily chemical industries. It is one of the raw materials for bulk commodity resins such as polybutylene terephthalate (PBT), polybutylene succinate (PBS) and polyurethane.

[0003] At present, there are two main methods for preparing 1,4-butanediol in industry: one is the acetylene aldehyde method; the other is the maleic anhydride hydrogenation method. The acetylene aldehyde method is to react acetylene and formaldehyde to produce 1,4-butynediol, and then further catalytic hydrogenation to produce 1,4-butanediol. The production cost of this method is relatively low, but calcium carbide is a high-energy consumption raw material. The maleic anhydride hydrogenation method is to hydrogenate maleic anhydride and its derivatives to prepare tetrahydrofuran, γ-butyrolactone and 1,4-butanediol mixture, and then separate them by distillation to prepare 1,4-butanediol. Maleic anhydride molecules have one C=C bond and two C=O bonds. Under certain catalytic conditions, hydrogenation will produce succinic anhydride, γ-butyrolactone, 1,4-butanediol and tetrahydrofuran in turn. The characteristic of this technology is that it can produce tetrahydrofuran, γ-butyrolactone and 1,4-butanediol at the same time according to different process conditions. The main disadvantages are that there are many hydrogenation by-products and the separation cost is high. In addition, the maleic anhydride hydrogenation acidic reaction system is generally not acid-resistant and will lead to poisoning of the active center, making long-term production impossible.

[0004] Therefore, how to prepare high-purity 1,4-butanediol by directional and highly selective hydrogenation is still an urgent problem to be solved and has great industrial value. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides 1,4-butanediol and a preparation method thereof. The high-strength molybdenum disulfide / porous carbon carrier is used to avoid the problem that the non-precious metal nickel and copper catalytic centers are lost to the product under pressurized hydrogenation conditions, thereby causing the catalyst activity to gradually decrease, thereby ensuring long-term production. In addition, the hydrophobic compound can make the hydrogenation product quickly desorb from the catalyst surface, and 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 to obtain the target product.

[0006] The first object of the present invention is to provide a 1,4-butanediol, wherein the purity of the 1,4-butanediol is ≥99.87%, the 1,4-butanediol does not contain methyl-1,4-butanediol and 2-(4-hydroxybutoxy)-tetrahydrofuran, and the rest are impurities; the impurities include tetrahydrofuran, the content of which is ≤0.05%, and n-butanol, the content of which is ≤0.05%.

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

[0008] S1, introducing maleic anhydride solution and hydrogen into a reactor equipped with a first-stage supported catalyst for a first-stage hydrogenation reaction to obtain a 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, introducing a γ-butyrolactone solution and hydrogen into a reactor equipped with a two-stage supported catalyst for a two-stage hydrogenation reaction, and then separating and purifying to obtain 1,4-butanediol; wherein the nickel loading amount of the two-stage supported catalyst is 5wt%-10wt%, the copper loading amount is 30wt%-60wt%, and the hydrophobic compound loading amount is 0.01wt%-0.2wt%;

[0010] The preparation method of the first-stage supported catalyst and the second-stage supported catalyst comprises the following steps: heat-treating asphalt and molybdenum disulfide to obtain a porous carbon / molybdenum disulfide carrier; 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 n≥6; the porous carbon / molybdenum disulfide carrier is impregnated in the mixed solution, and is subjected to aging, drying and thermal reduction treatment.

[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, 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 first stage hydrogenation reaction is 1MPa-10MPa, the temperature is 25℃-100℃, and the space velocity is 0.6hr -1 -6.0hr -1 ; The flow rate ratio of the maleic anhydride solution and hydrogen is (0.1-5):(0.1-100).

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

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

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

[0016] In one embodiment of the present invention, the mass ratio of the asphalt to molybdenum disulfide is 1:5-5:1; and the molybdenum disulfide is a nano-sheet structure with 5-20 layers.

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

[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 acetylacetonate, 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°C-80°C, and the time is 12h-16h; the drying temperature is 100°C-150°C, and the time is 10h-14h; the thermal reduction treatment is carried out in a hydrogen atmosphere, heating to 160°C-200°C at a rate of 10°C / h-20°C / h, and reducing for 6h-10h.

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

[0021] The porous carbon / molybdenum disulfide carrier of the present invention, due to the layered structure characteristics of molybdenum disulfide, when the carrier is subjected to high temperature treatment, the asphalt will extend along the layered voids, and then undergo dehydration, deorganization and other processes at a certain temperature to form a layered carbon structure, which is firmly combined with molybdenum disulfide and produces a large number of pore structures, which is conducive to the dispersion of active metal components. At the same time, this composite carrier structure naturally has a very high mechanical strength, and it is easy to achieve a particle strength of ≥450N / cm, while the particle strength of traditional alumina is difficult to achieve this. The mechanical strength of alumina particles of commercial catalyst carriers can generally reach 100N / cm.

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

[0023] (1) The supported catalyst of the present invention has a strength of more than 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 the present invention uses high-strength porous carbon / molybdenum disulfide as a carrier. The porous carbon / molybdenum disulfide carrier has a certain hydrogenation activity, which can promote the improvement of reaction activity, reduce the reaction temperature, improve the reaction selectivity, and thus improve the purity of the product. In addition, it can solve the problem that the non-precious metal nickel and copper catalytic centers are lost to the product under pressurized hydrogenation conditions, thereby causing the catalyst activity to gradually decrease and the long-term production cannot be guaranteed.

[0025] (3) The supported catalyst of the present invention uses a hydrophobic compound as an additive, 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 speed, and on the other hand, it can avoid further reaction of the product on the catalyst surface. 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 ultimate goal of achieving a product purity that can reach the polymerization grade, and does not contain methyl-1,4-butanediol and 2-(4-hydroxybutoxy)-tetrahydrofuran. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with specific embodiments so that those skilled in the art can better understand the present invention and implement it. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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 the present invention, unless otherwise explained, technical and scientific terms used in the present invention have the same meanings as commonly understood by those skilled in the art to which the present invention belongs.

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

[0029] In the present invention, unless otherwise stated, the experimental methods used in the embodiments of the present invention are conventional methods unless otherwise stated, and the materials, reagents, etc. used are all commercially available unless otherwise stated.

[0030] In the present invention, unless otherwise specified, the molybdenum disulfide used in the embodiments of the present invention is a nanosheet structure with 5-20 layers.

[0031] Example 1

[0032] The 1,4-butanediol and preparation method thereof of the present embodiment specifically comprise the following steps:

[0033] S1. Preparation of first-stage supported catalyst and second-stage supported catalyst

[0034] S11. Preparation of porous carbon / molybdenum disulfide carrier: Asphalt and molybdenum disulfide were stirred and mixed in a mass ratio of 1:1, and heat treated at 300°C for 4 h 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 / m 3 A porous carbon / molybdenum disulfide support;

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

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

[0037] S14, preparation of a first-stage loaded catalyst and a second-stage loaded catalyst: the porous carbon / molybdenum disulfide carrier was immersed in the first-stage mixed solution and the second-stage mixed solution respectively, aged at 60°C for 14h under stirring, then dried at 120°C for 12h, and finally loaded into tube arrays, heated to 200°C at a heating rate of 20°C / h under hydrogen conditions for reduction for 6h, and a first-stage loaded catalyst with a cluster length of 115nm, a width of 80nm, and a thickness of 23nm and a second-stage loaded catalyst with a cluster length of 125nm, a width of 85nm, and a thickness of 19nm were obtained respectively;

[0038] S2. Preparation of 1,4-butanediol

[0039] S21, preparation of maleic anhydride solution: dissolving maleic anhydride in tetrahydrofuran to obtain a maleic anhydride solution with a mass fraction of 5 wt%;

[0040] S22. Preparation of γ-butyrolactone solution: Maleic anhydride solution and hydrogen were mixed at flow rates of 0.5 mL / min and 200 mL / min respectively and then continuously introduced into a 50 mL hydrogenation tubular reactor equipped with a first stage supported catalyst for reaction at a reaction temperature of 96°C, a reaction pressure of 2.8 MPa(A), and a space velocity of 0.6 hr -1 , to obtain a γ-butyrolactone solution;

[0041] S23, Preparation of 1,4-butanediol: γ-butyrolactone solution and hydrogen were mixed at flow rates of 0.5 mL / min and 200 mL / min respectively and then continuously introduced into a 50 mL hydrogenation tubular reactor equipped with a two-stage supported catalyst for reaction at a reaction temperature of 130°C, a reaction pressure of 5.2 MPa, and a space velocity of 0.6 hr -1 , and then continuously enters the distillation separation tower for separation and purification to obtain the product.

[0042] Example 2

[0043] The method is basically the same as Example 1, except that during the preparation of the first-stage supported catalyst and the second-stage supported catalyst, basic nickel carbonate is replaced by nickel nitrate.

[0044] Example 3

[0045] The method is basically the same as Example 1, except that during the preparation of the first-stage supported catalyst and the second-stage supported catalyst, copper nitrate is replaced by copper chloride.

[0046] Example 4

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

[0048] Example 5

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

[0050] Comparative Example 1

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

[0052] Comparative Example 2

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

[0054] Comparative Example 3

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

[0056] Comparative Example 4

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

[0058] Test Example 1

[0059] According to the HG / T 2782 standard, the strength test of the first-stage supported catalyst and the second-stage supported catalyst of Examples 1-5 and Comparative Example 4 was carried out. The results are shown in Table 1:

[0060] Table 1

[0061]

[0062] It can be seen from Table 1 that the strength of the supported catalyst prepared in the example 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 product purity and impurity content of Examples 1-5 and Comparative Examples 1-4 were tested by gas chromatography, with a gas chromatography column HP-5 (30m×320μm×0.25μm) and an FID detector; the column temperature conditions were an initial temperature of 60°C, a first-order termination temperature of 90°C, a heating rate of 15°C / min, and a holding time of 2min, a second-order termination temperature of 230°C, a heating rate of 10°C / min, an injection port temperature of 260°C, a split ratio of 100:1, an injection volume of 0.2μL, a hydrogen flow rate of 30mL / min, and a nitrogen flow rate of 25mL / min. Acetone was used as the solvent to establish standard curves 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 the 1000h continuous hydrogenation process experiment are shown in Table 2:

[0065] Table 2

[0066]

[0067]

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

[0069] Obviously, the above embodiments are only examples for clear explanation and are not intended to limit the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the protection scope of the invention.

Claims

1. A 1,4-butanediol, characterized in that The purity of the 1,4-butanediol is ≥99.87%, and it does not contain methyl-1,4-butanediol and 2-(4-hydroxybutoxy)-tetrahydrofuran, and the rest are impurities; the impurities include tetrahydrofuran, the content of which is ≤0.05%, and n-butanol, the content of which is ≤0.05%.

2. A method for preparing 1,4-butanediol as claimed in claim 1, characterized in that: The following steps are involved: S1, introducing maleic anhydride solution and hydrogen into a reactor equipped with a first-stage supported catalyst for a first-stage hydrogenation reaction to obtain a 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%; S2, introducing a γ-butyrolactone solution and hydrogen into a reactor equipped with a two-stage supported catalyst for a two-stage hydrogenation reaction, and then separating and purifying to obtain 1,4-butanediol; wherein the nickel loading amount of the two-stage supported catalyst is 5wt%-10wt%, the copper loading amount is 30wt%-60wt%, and the hydrophobic compound loading amount is 0.01wt%-0.2wt%; The preparation method of the first-stage supported catalyst and the second-stage supported catalyst comprises the following steps: heat-treating asphalt 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 the structural formula: n≥6; the porous carbon / molybdenum disulfide carrier is impregnated in the mixed solution, and is subjected to aging, drying and thermal reduction treatment.

3. The method for preparing 1,4-butanediol according to claim 2, 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, γ-butyrolactone, ether, ethyl acetate, ethyl formate and methyl acetate.

4. The method for preparing 1,4-butanediol according to claim 2, characterized in that: In S1, the pressure of the first stage hydrogenation reaction is 1MPa-10MPa, the temperature is 25℃-100℃, and the space velocity is 0.6hr -1 -6.0hr -1 ; The flow rate ratio of the maleic anhydride solution and hydrogen is (0.1-5):(0.1-100).

5. The method for preparing 1,4-butanediol according to claim 2, characterized in that: In S2, the pressure of the second stage hydrogenation reaction is 3MPa-10MPa, the temperature is 100℃-200℃, and the space velocity is 0.6hr -1 -6.0hr -1 ; The flow rate ratio of the maleic anhydride solution and hydrogen is (0.1-5):(0.1-100).

6. The method for preparing 1,4-butanediol according to claim 2, characterized in that: The mass ratio of the asphalt to molybdenum disulfide is 1:5-5:1; and the molybdenum disulfide is a nano-sheet structure with 5-20 layers.

7. The method for preparing 1,4-butanediol according to claim 2, characterized in that: The heat treatment is carried out in an oxygen atmosphere at 200° C.-400° C. for 3 h-8 h.

8. The method for preparing 1,4-butanediol according to claim 2, characterized in that: The nickel precursor is selected from one or more of nickel chloride, nickel nitrate, nickel sulfate, basic nickel carbonate, nickel acetylacetonate, 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.

9. The method for preparing 1,4-butanediol according to claim 2, characterized in that: The aging temperature is 50°C-80°C, and the time is 12h-16h; the drying temperature is 100°C-150°C, and the time is 10h-14h; the thermal reduction treatment is carried out in a hydrogen atmosphere, heating to 160°C-200°C at a rate of 10°C / h-20°C / h, and reducing for 6h-10h.

10. The method for preparing 1,4-butanediol according to claim 2, characterized in that: The pore volume of the porous carbon / molybdenum disulfide carrier in the first-stage supported catalyst and the second-stage supported catalyst is 0.2 mL / g-0.7 mL / g, the particle size is 3 mm-5 mm, and the bulk density is 750 kg / m 3 -1100kg / m 3 ; The length of the cluster is 80nm-150nm, the width is 30nm-100nm, and the thickness is 10nm-30nm.

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