A bio-based tetrahydrofuran prepared by hydrogenation of bio-based succinic acid and its preparation method

Abstract

This invention relates to a method for preparing bio-based tetrahydrofuran by hydrogenation of bio-based succinic acid. The method involves continuously introducing a bio-based succinic acid solution and hydrogen gas into a fixed bed containing a nickel-based catalyst for hydrogenation to obtain a crude product. The crude product is then purified in a separation tower to obtain bio-based tetrahydrofuran. The purity of the obtained bio-based tetrahydrofuran is ≥99.99%, with the remainder being impurities. These impurities are γ-butyrolactone and 1,4-butanediol; the content of γ-butyrolactone is ≤0.006%, and the content of 1,4-butanediol is ≤0.005%.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical raw material synthesis, in particular to a kind of bio-based tetrahydrofuran prepared by bio-based succinic acid hydrogenation and a preparation method thereof. BACKGROUND

[0002] Tetrahydrofuran is a kind of heterocyclic organic compound, which is an important organic and fine chemical raw material, and is widely used in pharmaceutical, chemical and daily chemical fields. It is the raw material for the synthesis of polytetrahydrofuran (PTMEG).

[0003] At present, there are three kinds of tetrahydrofuran: 1, furfural method; 2, 1, 4-butanediol dehydration method, 3, hydrogenation method. Furfural method is to separate furan by decarbonylation reaction of furfural, and then to separate and purify tetrahydrofuran by hydrogenation. The 1, 4-butanediol dehydration method is to dehydrate 1, 4-butanediol into a ring under the condition of an acidic catalyst, and then to obtain high-purity tetrahydrofuran by separation. This scheme is the most commonly used method for producing tetrahydrofuran in industry. In this scheme, since 1, 4-butanediol contains methyl butanediol, tetrahydrofuran will contain methyl tetrahydrofuran after dehydration. The hydrogenation method is to prepare a mixture of succinic anhydride, tetrahydrofuran, gamma-butyrolactone and 1, 4-butanediol by hydrogenation of maleic anhydride, succinic acid and its derivatives, and then to separate and prepare tetrahydrofuran by rectification. The characteristics of this technology are that succinic anhydride, tetrahydrofuran, gamma-butyrolactone and 1, 4-butanediol can be produced simultaneously according to different process conditions. The main disadvantages are that there are many hydrogenation by-products, the separation cost is high, and the succinic anhydride and succinic acid hydrogenation acidic reaction system is generally not resistant to acid system, which will cause poisoning of the active center and cannot be produced for a long period. By adjusting the catalytic active center, high-purity tetrahydrofuran can be prepared by directional high-selectivity hydrogenation without methyl tetrahydrofuran, which has great industrialization potential. SUMMARY

[0004] To solve the above technical problems, the present application provides a kind of bio-based succinic acid hydrogenation preparation of bio-based tetrahydrofuran and a preparation method thereof. The bio-based tetrahydrofuran of the present application is prepared by directly hydrogenating 5wt%-30wt% bio-based succinic acid solution; the purity of the obtained bio-based tetrahydrofuran is ≥99.99%. The catalyst used is composed of ordered composite porous carbon / molybdenum disulfide material carrier, nickel precursor compound active component and hydrophobic compound component.

[0005] The present application is realized by the following technical scheme:

[0006] The first object of the present application is to provide a kind of bio-based succinic acid hydrogenation preparation of bio-based tetrahydrofuran, the purity of the bio-based tetrahydrofuran is ≥99.99%, and the rest is impurity;The impurity is gamma-butyrolactone and 1, 4 butanediol;The content of gamma-butyrolactone is ≤0.006%, and the content of 1, 4 butanediol is ≤0.005%.

[0007] It is a second object of the present application to provide a method for preparing bio-based tetrahydrofuran by hydrogenation of bio-based succinic acid, comprising the following steps:

[0008] (1) preparing a bio-based succinic acid solution;

[0009] (2) continuously feeding the bio-based succinic acid solution obtained in step (1) and hydrogen into a fixed bed containing a nickel-based catalyst to perform a hydrogenation reaction, to obtain a crude product;

[0010] (3) feeding the crude product obtained in step (2) into a separation column to perform separation and purification, to obtain bio-based tetrahydrofuran.

[0011] In an embodiment of the present application, in step (1), the mass percentage of the bio-based succinic acid solution is 5wt%-30wt%.

[0012] In an embodiment of the present application, in step (1), the solvent of the bio-based succinic acid solution is selected from one or more of tetrahydrofuran, γ-butyrolactone, diethyl ether, ethyl acetate, ethyl formate and methyl acetate; preferably tetrahydrofuran and γ-butyrolactone.

[0013] In an embodiment of the present application, in step (2), the flow rate of the bio-based succinic acid solution is 0-5mL / min;

[0014] and / or, the flow rate of the hydrogen is 0-100mL / min.

[0015] In an embodiment of the present application, in step (2), the pressure of the hydrogenation reaction is 1MPa-10MPa;

[0016] and / or, the temperature of the hydrogenation reaction is 25℃-100℃;

[0017] and / or, the system reaction space velocity of the hydrogenation reaction is 0.6hr -1 -6.0hr -1 .

[0018] In an embodiment of the present application, in step (2), the nickel loading of the nickel-based catalyst is 30wt%-60wt%, and the content of the hydrophobic compound is 0.01wt%-0.2wt%.

[0019] In an embodiment of the present application, the nickel-based catalyst comprises catalytically active center clusters composed of nickel and a hydrophobic compound; the size of the catalytically active center clusters is: length 80nm-150nm, width 30nm-100nm, and thickness 10nm-30nm;

[0020] The particle strength of the nickel-containing base catalyst is greater than or equal to 400 N / cm.

[0021] In an embodiment of the present application, the nickel content of the nickel-containing base catalyst is 30 wt% to 60 wt%, and the content of the hydrophobic compound is 0.01 wt% to 0.2 wt%.

[0022] In an embodiment of the present application, in step (2), the nickel-containing base catalyst is prepared by the following preparation method:

[0023] S1, under the condition of oxygen, stirring and mixing asphalt with molybdenum disulfide, and performing heat treatment to obtain a porous carbon / molybdenum disulfide material carrier;

[0024] S2, dissolving a nickel precursor compound, a hydrophobic compound and an acid solution in water to obtain a mixed solution;

[0025] S3, immersing the porous carbon / molybdenum disulfide material carrier obtained in step S1 in the mixed solution obtained in step S2 to obtain a catalyst intermediate;

[0026] S4, performing aging, drying and reduction treatment on the catalyst intermediate obtained in step S3 to obtain the nickel-containing base catalyst.

[0027] In an embodiment of the present application, in step S1, the mass average molecular weight of the asphalt is 600 to 2000, and the molecular weight distribution is 1.2 to 1.4;

[0028] And / or, the molybdenum disulfide has a nanosheet structure of 5 to 20 layers.

[0029] In an embodiment of the present application, in step S1, the mass ratio of the asphalt to the molybdenum disulfide is 1:5 to 5:1;

[0030] In an embodiment of the present application, in step S1, the heat treatment is performed at a temperature of 200°C to 400°C for 3h to 8h.

[0031] In an embodiment of the present application, in step S2, the acid solution is a nitric acid solution with a concentration of 1 mol / L to 6 mol / L.

[0032] In an embodiment of the present application, in step S2, the nickel precursor compound 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;

[0033] And / or, the hydrophobic compound has the structural formula wherein n is greater than or equal to 6;

[0034] And / or, the mass ratio of the nickel precursor compound to the hydrophobic compound is 1–90:0.1–1.

[0035] In one embodiment of the present invention, in step S4, the aging conditions are: aging at 50℃~80℃ for 12h~16h;

[0036] And / or, the drying conditions are: 100℃~140℃, for 10h~14h.

[0037] In one embodiment of the present invention, in step S4, the reduction conditions are: reduction at 160°C to 200°C for 6 to 10 hours under hydrogen atmosphere and atmospheric pressure. ， This enables the nickel-based catalyst to have hydrogenation activity.

[0038] In one embodiment of the present invention, in step S4, the pore volume of the porous carbon / molybdenum disulfide material carrier is 0.2 mL / g to 0.7 mL / g;

[0039] And / or, the particle size of the porous carbon / molybdenum disulfide material carrier is 3 mm to 5 mm;

[0040] And / or, the bulk density of the porous carbon / molybdenum disulfide material carrier is 750 kg / m³. 3 ~1100kg / m 3 .

[0041] In the nickel-based catalyst of the present invention, nickel exists in atomic form and is adsorbed onto the support by physical adsorption with hydrophobic compounds. The catalytic active center clusters exist in the pores of the support, both on the surface and inside.

[0042] The technical solution of this invention uses a high-strength molybdenum disulfide / porous carbon support, which can avoid the loss of non-precious metal nickel catalytic centers into the product under pressurized hydrogenation conditions, thus preventing the catalyst activity from gradually decreasing and ensuring long-cycle production. In addition, the hydrophobic compound can enable the hydrogenated product to desorb quickly from the catalyst surface, and the degree of hydrogenation of the two C=O bonds of succinic acid can be controlled by adjusting the reaction pressure and temperature, thereby obtaining the target product.

[0043] The porous carbon / molybdenum disulfide carrier of the present application, due to the layered structure characteristics of molybdenum disulfide, during the high-temperature treatment process of the carrier, the pitch will be extended along the layered gap, and then through the dehydration, de-organic matter and other processes at a certain temperature, the carbon with layered structure is formed, and the molybdenum disulfide is firmly combined, and a large number of pore structures are generated, which is beneficial to the dispersion of the active metal component. At the same time, this composite carrier structure naturally has very high mechanical strength, and it is very easy to achieve a particle strength of ≥400N / cm, while the particle strength of traditional alumina is difficult to achieve this, and the mechanical strength of the alumina particles of the commercial catalyst carrier can generally reach 100N / cm.

[0044] Compared with the prior art, the present application has the following advantages:

[0045] The present application provides a kind of bio-based succinic acid hydrogenation preparation bio-based tetrahydrofuran and preparation method thereof.The present application is by continuously entering the fixed bed containing nickel-based catalyst with bio-based succinic acid solution and hydrogen into hydrogenation reaction, obtain crude product;The obtained crude product enters separation column and is purified, to obtain bio-based tetrahydrofuran.The purity of the obtained bio-based tetrahydrofuran is ≥99.99%, and the rest is impurity;The impurity is gamma-butyrolactone and 1,4-butanediol;The content of gamma-butyrolactone is ≤0.006%, and the content of 1,4-butanediol is ≤0.005%.The catalyst used in the present application has ultra-high strength of ≥400N / cm, and the metal is not easy to lose in the reaction, which plays a key role in the synthesis of high-purity tetrahydrofuran.

[0046] The catalyst used in the present application uses porous carbon / molybdenum disulfide as carrier, and the catalyst carrier itself has certain hydrogenation activity, which can promote the improvement of reaction activity, reduce the reaction temperature, improve the selectivity of the reaction, and then improve the purity of the product.The catalyst used in the present application uses hydrophobic compound as additive, which can make the product tetrahydrofuran quickly desorb from the surface of the catalyst, not only can speed up the reaction speed, but also can avoid the further reaction of the product on the surface of the catalyst, so as to realize the final goal that the purity of the product can reach polymerization grade. DETAILED DESCRIPTION

[0047] The present application will be further described below in conjunction with specific examples, so that those skilled in the art can better understand the present application and implement it, but the examples are not limiting to the present application.

[0048] The experimental methods used in the following examples are conventional methods unless otherwise specified, and the materials, reagents, etc., unless otherwise specified, can be obtained from commercial channels.

[0049] The product purity and impurity content were tested by gas chromatography analysis method, column gas chromatography column HP-5 (30 m x 320 pm x 0.25 pm), FID detector. The column temperature condition is as follows: initial temperature 60℃, first-order termination temperature 90℃, temperature rising rate 15℃ / min, holding time 2 min, second-order termination temperature: 230℃, temperature rising rate 10℃ / min, injection port temperature 260℃, split ratio 100:1, injection volume: 0.2 pL, hydrogen flow rate: 30 mL / min, nitrogen flow rate: 25 mL / min. Acetone was used as the solvent to establish the standard curve of bio-based 1,4 succinic acid, tetrahydrofuran, g-butyrolactone and 1,4 butanediol.

[0050] The strength test of the nickel-containing base catalyst was carried out according to the standard of HG / T 2782.

[0051] Example 1

[0052] The present embodiment provides a preparation method of bio-based tetrahydrofuran prepared by hydrogenation of bio-based succinic acid, and the specific steps are as follows:

[0053] (1) Preparation of nickel-containing base catalyst: mix pitch and molybdenum disulfide in a mass ratio of 1:1, heat treat at 300℃ for 4h under oxygen condition to prepare a porous carbon / molybdenum disulfide carrier with a pore volume of 0.5 mL / g and a particle size of 5 mm; weigh 50.00 g of basic nickel carbonate, 159.5 mL (5 mol / L) of dilute nitric acid solution, 0.30 g of sodium dodecyl sulfonate, and 500.00 g of deionized water, stir at 45℃ until all solids are dissolved to obtain a nickel-containing precursor compound solution; immerse the obtained porous carbon / molybdenum disulfide carrier in the nickel-containing precursor compound solution, and under stirring, age the mixture at a temperature of 60℃ for 14h, then dry at 120℃ for 12h, and reduce at 200℃ under hydrogen condition for 6h to obtain a nickel-containing base catalyst.

[0054] (2) The nickel-containing base catalyst is used for hydrogenation of bio-based succinic acid tetrahydrofuran solution; the bio-based succinic acid tetrahydrofuran solution with a flow rate of 0.5 mL / min is mixed with hydrogen gas with a flow rate of 200 mL / min, and then continuously enters a 50 mL nickel-containing base catalyst hydrogenation column reactor, the reaction temperature is 145℃, the reaction pressure is 6.8 MPa(A), and the product tetrahydrofuran is separated by continuously entering a rectification separation tower.

[0055] Example 2

[0056] The present embodiment provides a preparation method of bio-based tetrahydrofuran prepared by hydrogenation of bio-based succinic acid, and the specific steps are as follows:

[0057] In step (1), the basic nickel carbonate is replaced by nickel nitrate;

[0058] The obtained nickel-containing catalyst is used for the hydrogenation reaction of bio-based succinic acid, and bio-based tetrahydrofuran is separated and obtained.

[0059] Example 3

[0060] The present example provides a preparation method of bio-based tetrahydrofuran prepared by hydrogenation of bio-based succinic acid, which is similar to Example 1, and the only difference is that:

[0061] In the catalytic hydrogenation process, a tetrahydrofuran solution containing 10wt% bio-based succinic acid is prepared, and the product tetrahydrofuran is obtained by catalytic hydrogenation.

[0062] Example 4

[0063] The present example provides a preparation method of bio-based tetrahydrofuran prepared by hydrogenation of bio-based succinic acid, which is similar to Example 1, and the only difference is that:

[0064] In the catalytic hydrogenation process, a γ-butyrolactone solution containing 5wt% bio-based succinic acid is prepared, and the product tetrahydrofuran is obtained by catalytic hydrogenation.

[0065] Comparative Example 1

[0066] The present example provides a preparation method of bio-based tetrahydrofuran prepared by hydrogenation of bio-based succinic acid, which is similar to Example 1, and the only difference is that:

[0067] (1) Preparation of nickel-containing catalyst: The pitch and molybdenum disulfide are stirred and mixed according to a mass ratio of 1:1, and a porous carbon / molybdenum disulfide carrier with a pore volume of 0.5 mL / g and a particle size of 5 mm is prepared by heat treatment at 300°C for 4h under oxygen conditions; 50.00g of basic nickel carbonate, 159.5mL (5mol / L) of dilute nitric acid solution, and 500.00g of deionized water are stirred at 45°C until all the solids are dissolved to obtain a nickel-containing precursor compound solution; the obtained porous carbon / molybdenum disulfide carrier is immersed in the nickel-containing precursor compound solution, and the mixture is aged at a temperature of 60°C for 14h under stirring, then dried at 120°C for 12h, and reduced at 200°C under hydrogen for 6h to obtain a nickel-containing catalyst.

[0068] (2) Preparation of a tetrahydrofuran solution containing 5wt% bio-based succinic acid; the tetrahydrofuran solution containing bio-based succinic acid with a flow rate of 0.5mL / min is mixed with hydrogen gas with a flow rate of 200mL / min, and then continuously introduced into a 50mL nickel-containing catalyst hydrogenation column reactor, the reaction temperature is 145°C, the reaction pressure is 6.8MPa(A), and the product tetrahydrofuran is separated and obtained by continuously entering a rectification separation tower.

[0069] Comparative Example 2

[0070] The comparative example provides a preparation method of a bio-based tetrahydrofuran prepared by hydrogenation of bio-based succinic acid, and the specific steps are as follows:

[0071] (1) Preparation of a nickel-containing catalyst: 50.00 g of basic nickel carbonate, 159.5 mL (5 mol / L) of dilute nitric acid solution, 0.30 g of sodium dodecyl sulfonate, and 500.00 g of deionized water were weighed and stirred at 45°C until all the solids were dissolved to obtain a nickel-containing precursor compound solution; the obtained porous carbon was immersed in the nickel-containing precursor compound solution, and under stirring, the mixture was aged at a temperature of 60°C for 14 h, then dried at 120°C for 12 h, and reduced under hydrogen at 200°C for 6 h to obtain a nickel-containing catalyst.

[0072] (2) A tetrahydrofuran solution of bio-based succinic acid with a mass percentage of 5wt% was prepared; the tetrahydrofuran solution of bio-based succinic acid with a flow rate of 0.5 mL / min was mixed with hydrogen gas with a flow rate of 200 mL / min, and then continuously entered a 50 mL nickel-containing catalyst hydrogenation column reactor, the reaction temperature was 145°C, the reaction pressure was 6.8 MPa (A), and the product tetrahydrofuran was separated by continuously entering a rectification separation tower.

[0073] Test example

[0074] The strength of the catalysts prepared in the examples and comparative examples was tested according to the standard specified in HG / T 2782, and the test results are shown in Table 1 below:

[0075] Table 1

[0076] Catalyst Strength (N / cm) Example 1 453.8 Example 2 455.2 Example 3 453.8 Example 4 453.8 Comparative Example 1 451.5 Comparative Example 2 200.2

[0077] As can be seen from Table 1, the strength of the supported catalyst prepared in the examples exceeds 450 N / cm, and by compounding high-strength molybdenum disulfide with porous carbon, the strength of the supported catalyst can be greatly improved.

[0078] The product purity and impurity content were tested by gas chromatography analysis method, and the conversion rate after 1000 h of continuous experiment of the hydrogenation process is shown in Table 2 below:

[0079] Table 2

[0080]

[0081] As can be seen from Table 2, the catalyst of the present application still has high catalytic activity and selectivity after 1000 h of continuous hydrogenation, and can prepare high-purity tetrahydrofuran under certain pressure and temperature conditions.

[0082] Obviously, the above embodiments are merely example for clearly illustrating, and are not limitation to the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments are not required to be enumerated, and the obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A process for the preparation of bio-based tetrahydrofuran prepared by hydrogenation of bio-based succinic acid, characterized in that, The method comprises the following steps: (1) preparing a bio-based succinic acid solution; (2) continuously feeding the bio-based succinic acid solution obtained in step (1) and hydrogen into a fixed bed containing a nickel-containing catalyst to perform a hydrogenation reaction to obtain a crude product; (3) feeding the crude product obtained in step (2) into a separation column to separate and purify to obtain bio-based tetrahydrofuran; In step (2), the nickel-containing catalyst is prepared by the following method: S1, under the condition of oxygen, stirring and mixing asphalt and molybdenum disulfide, and performing heat treatment to obtain a porous carbon / molybdenum disulfide material carrier; S2, dissolving a nickel precursor compound, a hydrophobic compound and an acid solution in water to obtain a mixed solution; S3, immersing the porous carbon / molybdenum disulfide material carrier obtained in step S1 in the mixed solution obtained in step S2 to obtain a catalyst intermediate; S4, aging, drying and reducing the catalyst intermediate obtained in step S3 to obtain the nickel-containing catalyst; The hydrophobic compound is sodium dodecyl sulfonate.

2. The production method according to claim 1, characterized by, In step (1), the mass percentage of the bio-based succinic acid solution is 5 wt%-30 wt%.

3. The preparation method according to claim 1, characterized in that, In step (1), the solvent of the bio-based succinic acid solution is selected from one or more of tetrahydrofuran, gamma-butyrolactone, diethyl ether, ethyl acetate, ethyl formate and methyl acetate.

4. The method of claim 1, wherein, In step (2), the flow rate of the bio-based succinic acid solution is 0-5 mL / min; And / or, the flow rate of the hydrogen is 0-100 mL / min.

5. The preparation method according to claim 1, characterized in that, In step (2), the pressure of the hydrogenation reaction is 1 MPa-10 MPa; And / or, the temperature of the hydrogenation reaction is 25℃-100℃; and / or the system reaction space velocity of the hydrogenation reaction is 0.6 hr -1 6.0 hr -1 .

6. The method of claim 1, wherein, In step (2), the nickel loading of the nickel-containing catalyst is 30 wt%-60 wt%, and the content of the hydrophobic compound is 0.01 wt%-0.2 wt%.

7. The preparation method according to claim 1, characterized in that, In step S2, the nickel precursor compound 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; And / or, the mass ratio of the nickel precursor compound to the hydrophobic compound is 1-90:0.1-1.

8. The method of claim 1, wherein, In step S4, the reduction conditions are: reduction at 160℃-200℃ for 6 h-10 h.

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