Bio-based 1,4-butanediol production method

Abstract

To provide a method for producing biobased 1,4-butanediol which reduces carbon dioxide emissions and achieves recycling of biomass energy, because a supply source of a raw material is widely recyclable.SOLUTION: A method for producing biobased 1,4-butanediol includes the steps of: mixing a biobased succinic acid and an alcoholic compound and carrying out esterification reaction, to obtain oligomer polyester; subjecting the oligomer polyester to hydrogenation reduction under a catalyst, to obtain crude 1,4-butanediol; and purifying the crude 1,4-butanediol to obtain the biobased 1,4-butanediol. Biobased 1,4-butanediol as a target product is produced using a biobased succinic acid and an alcoholic compound as raw materials by esterification and hydrogenation reduction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the technical field of organic synthesis, and in particular to a method for producing bio-based 1,4-butanediol. [Background technology]

[0002] 1,4-Butanediol (BDO) is a transparent liquid at room temperature and an important chemical raw material with good chemical stability. It can be used in the synthesis of pharmaceuticals and the preparation of advanced coatings, advanced inks, advanced resins, synthetic fibers, rubbers, surfactants, etc.

[0003] Currently, the main methods for producing 1,4-butanediol are the Reppe process, maleic anhydride process, allyl alcohol process, and butadiene process. All of these traditional processes use petrochemicals as their raw material source. The Reppe process uses acetylene and formaldehyde as raw materials. The process first synthesizes 1,4-butynediol from acetylene and formaldehyde in the presence of a copper catalyst, and then hydrogenates the 1,4-butynediol to produce 1,4-butanediol. The Reppe process has the advantage of low operating costs, but the high acetylene partial pressure in the ethynylation stage requires a high reactor design safety factor of 12-20, significantly increasing initial capital investment costs. At the same time, high acetylene partial pressure can easily produce polyacetylene, which can cause pipe blockages, reduce production efficiency, and easily deactivate the catalyst. Considering the shortcomings of the traditional Reppe process, the modified Reppe process is safer, requires less capital investment, and has a longer production cycle. The modified Reppe process is mainly divided into four processes: BASF, Dupont, IS, and Linde & SK. For example, Patent Document 1 discloses a comprehensive method for continuously producing 1,4-butanediol, which includes step (I) of reacting formaldehyde with acetylene in the presence of a copper catalyst at a pH value of 5 to 8, where the molar ratio of formaldehyde to acetylene is at most 2:1; step (II) of subjecting the resulting aqueous mixture containing butynediol to intermediate buffering for 0.1 to 100 hours; step (III) of hydrogenating the mixture obtained after the intermediate buffering; and step (IV) of distilling the hydrogenation product obtained in step III to obtain 1,4-butanediol. Patent Document 2 discloses a method for producing butanediol by two-step hydrogenation of butynediol. In the current two-stage hydrogenation of butynediol to produce butanediol, considering the requirements for adaptability to water-containing reaction systems, variations in water content within the reaction system, and the suppression of carbon deposit formation, two-stage hydrogenation catalysts A and B contain a support, a metal active component, and silane groups, to which silane groups are grafted by silylation, of which the silane groups are estimated to account for 0.1 wt% to 12 wt% of the total weight of the hydrogenation catalyst. Compared with conventional technologies, the hydrogenation catalysts have superior activity and selectivity, demonstrating clear compatibility with raw materials. The presence of water has little effect on the catalytic performance of the hydrogenation catalyst, while significantly suppressing the formation of carbon deposits on the catalyst surface, thereby extending the catalyst's service life and enabling a long and stable operation cycle of the hydrogenation reaction system. Patent Document 3 discloses that the production process mainly includes a formaldehyde stage, an acetylenization stage, a hydrogenation stage, and a product rectification stage. The formaldehyde stage mainly involves the catalytic reaction of raw material methanol and air to produce formaldehyde; the acetylenization stage mainly involves the catalytic reaction of acetylene and formaldehyde to produce purified 1,4-butynediol; the hydrogenation stage mainly involves the use of 1,4-butynediol and hydrogen from the upstream furnace gas purification stage under a certain pressure to produce crude 1,4-butanediol through the catalytic reaction; and the product rectification stage mainly involves the rectification of 1,4-butanediol to obtain high-purity 1,4-butanediol product.

[0004] The butadiene process converts butadiene to 1,4-diacetoxy-2-butene through an acetyl oxidation reaction, which is then further hydrogenated to obtain 1,4-diacetoxybutane, and finally hydrolyzed to obtain the target product, 1,4-butanediol. This process has the advantages of high selectivity for the target product and the ability to flexibly control the ratio of tetrahydrofuran to 1,4-butanediol, but also has disadvantages such as high steam consumption and complex equipment. For example, Patent Document 4 discloses a method for producing 1,4-butanediol from butadiene, in which butadiene, acetic acid, and oxygen are used as raw materials and an oxyacetylation reaction is carried out in the presence of an oxyacetylation catalyst to obtain 1,4-diacetoxybutene, and hydrogen is reacted with the 1,4-diacetoxybutene in the presence of a hydrogenation catalyst to obtain 1,4-diacetoxybutane, which is then hydrolyzed to obtain 1,4-butanediol, the hydrogenation catalyst using activated carbon as a carrier, and the active component containing Pt and a promoter element, the promoter element being at least one selected from iron-based metals and VA group metals. Patent Document 5 discloses a method for obtaining 1,4-diacetoxybutene by using butadiene, acetic acid, and oxygen as raw materials and carrying out an oxyacetylation reaction in the presence of an oxyacetylation catalyst, in which hydrogen reacts with 1,4-diacetoxybutene in the presence of a hydrogenation catalyst to obtain 1,4-diacetoxybutane, and 1,4-diacetoxybutane is hydrolyzed to obtain 1,4-butanediol, in which the hydrogenation catalyst uses activated carbon as a carrier, and the active component includes a Pt element and a promoter element, and the promoter element is selected from at least one metal element selected from metalloid group metals and Group VIIB metals.

[0005] In the allyl alcohol process, propylene oxide is first isomerized to produce allyl alcohol, which is then hydroformylated in the liquid phase using an aromatic hydrocarbon as the solvent and a rhodium-based catalyst and triphenylphosphine solution as the catalyst to produce 4-hydroxybutyraldehyde solution, which is then hydrogenated under the action of a Raney nickel catalyst to produce 1,4-butanediol.This process uses rare precious metals, which makes it expensive and unenvironmental, and has the disadvantages of low product selectivity and producing many by-products. For example, Patent Document 6 discloses using synthesis gas to hydroformylate allyl alcohol in an allyl alcohol feedstock to produce a hydroformylation product containing 4-hydroxybutyraldehyde and 3-hydroxy-2-methylpropionaldehyde, and hydrogenating at least a portion of the hydroformylation product to produce a 1,4-butanediol (BDO) product containing BDO and 1,3-methylpropanediol.

[0006] In the maleic anhydride process, maleic anhydride is used as a raw material, which is first reacted with methanol to produce maleic dimethyl ester, which is then hydrogenated to produce 1,4-butanediol with tetrahydrofuran as a by-product. This process has the disadvantages of high raw material costs and large capital investments. For example, Patent Document 7 describes a method for combining the maleic anhydride production process with the BDO production process, thereby saving the original equipment and energy consumption for rich oil analysis and solvent treatment in the n-butane maleic anhydride unit, and removing the impurities produced in the maleic anhydride unit together with the impurities in the BDO unit, thereby saving on equipment costs. Furthermore, when butanol is used as a raw material for maleic anhydride esterification to produce dibutyl maleate (DBM), the butanol by-product produced in the hydrogenation step can be utilized.

[0007] All of the above traditional methods use petrochemical-based raw materials as raw material sources, which are becoming increasingly scarce and non-renewable. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Chinese Patent No. 101244984 [Patent Document 2] Chinese Patent No. 102408307 [Patent Document 3] Chinese Patent No. 109651110 [Patent Document 4] Chinese Patent No. 108017509 [Patent Document 5] Chinese Patent No. 107915579 [Patent Document 6] Chinese Patent No. 111801312 [Patent Document 7] Chinese Patent No. 106083523 Summary of the Invention [Problem to be solved by the invention]

[0009] In view of this, the present invention aims to provide a bio-based 1,4-butanediol and its production method and applications. The present invention uses bio-based succinic acid as a raw material and produces the target product, bio-based 1,4-butanediol, through esterification and hydrogenation reduction, and the raw material source is wide and renewable. [Means for solving the problem]

[0010] In order to achieve the above object of the invention, the present invention provides the following technical solutions:

[0011] The present invention provides a method for producing bio-based 1,4-butanediol, A step of mixing bio-based succinic acid and an alcohol-based compound and subjecting them to an esterification reaction to obtain an oligomeric polyester; catalytically reducing the oligomeric polyester by hydrogenation to obtain crude 1,4-butanediol; and purifying the crude 1,4-butanediol to obtain the bio-based 1,4-butanediol.

[0012] Preferably, the alcohol-based compound includes one or more of butanol, pentanol, hexanol, ethylene glycol, and 1,4-butanediol.

[0013] Preferably, the molar ratio of the bio-based succinic acid to the alcohol-based compound is 1:1.2 to 2.4.

[0014] Preferably, the esterification reaction is carried out at a temperature of 160 to 210°C for a period of 4 to 8 hours.

[0015] Preferably, the ratio of hydrogen used in the hydrogenation reduction to the hydrogen ester of the oligomeric polyester is 80 to 200:1.

[0016] Preferably, the pressure of the hydrogenation reduction is 1 to 20 MPa, the temperature is 100 to 220° C., and the time is 2 to 6 hours.

[0017] Preferably, the catalyst is a supported copper-based catalyst.

[0018] Preferably, the supported copper catalyst is (1) mixing copper nitrate hexahydrate, aluminum nitrate nonahydrate, an active metal salt, the metal of which may include magnesium, manganese, nickel, cobalt, zinc, cerium, or zirconium, and water to obtain a metal ion salt solution; Sodium hydroxide, sodium carbonate, and water are mixed to obtain an alkaline precipitant, and the molar ratio is [OH - ]=2([M 2+ ]+[M 3+ ]) and [CO 3- ]=0.5[M 3+ ], and M represents a metal element; (3) adding the metal ion salt solution and the alkaline precipitant to the reactor at 60°C to carry out the precipitation reaction, obtaining a precipitated product, and maintaining the pH of the reaction system at 8-10; Step (4) of aging the precipitated product at 70°C for 24 hours to obtain ternary hydrotalcite; and (5) sequentially roasting and activating the ternary hydrotalcite to obtain the supported copper catalyst.

[0019] Preferably, the molar ratio of the copper nitrate hexahydrate, the metal in the active metal salt, and aluminum nitrate nonahydrate is 1-5:1:0.25-2.

[0020] Preferably, the roasting temperature is 400 to 800°C and the roasting time is 0.5 to 8 hours.

[0021] The present invention provides a method for producing bio-based 1,4-butanediol, which includes the steps of: mixing bio-based succinic acid and an alcohol compound for esterification to obtain an oligomeric polyester; hydrogenating the oligomeric polyester in the presence of a catalyst to obtain crude 1,4-butanediol; and purifying the crude 1,4-butanediol to obtain the bio-based 1,4-butanediol. [Effects of the Invention]

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention uses bio-based succinic acid and alcohol compounds as raw materials, and produces the target product, bio-based 1,4-butanediol, through esterification and hydrogenation reduction. Succinic acid is obtained through biological fermentation, and the raw material source is widely renewable. This not only reduces carbon dioxide emissions, realizes the reuse of biomass energy, increases the added value of products, and reduces environmental pollution, but also brings significant economic benefits. Furthermore, the alcohol compound in the present invention includes one or more of butanol, pentanol, hexanol, ethylene glycol, and 1,4-butanediol, and the esterification reaction between succinic acid and the alcohol compound can be carried out without a catalyst, eliminating the need for complicated post-treatment procedures such as post-treatment or catalyst separation after the esterification reaction is complete. Furthermore, 1,4-butanediol has a high boiling point that is significantly different from that of water, so it can be separated together with water by distillation. This allows the water produced by the esterification reaction to be separated from the reaction system, allowing the esterification reaction to proceed smoothly. At the same time, because no other alcohols are introduced during the esterification process, the intermediate product does not need to be distilled or purified, and can be used in the following procedure. Furthermore, in this invention, the supported copper catalyst is used for hydrogenation reduction, and a hydrotalcite-like precursor is prepared by coprecipitation at a certain pH value, and then decomposed by roasting to obtain the final active Cu catalyst. Because it is prepared by the coprecipitation method, the metal loading can be significantly improved compared with the conventional impregnation method. At the same time, by controlling the proportion of active metal and the roasting temperature, the surface morphology and physical and chemical properties of the supported copper catalyst can be changed. As a result, the catalyst has a high specific surface area, metal dispersion, suitable surface acidity and alkalinity, and Cu. + / Cu 0 Because of this ratio, the catalytic hydrogenation of oligomeric polyester using this catalyst can achieve lower hydrogenation pressure (1-20 MPa), lower hydrogenation temperature (100-220°C), and lower hydrogen ester ratio (hydrogen ester ratio 80-200:1), while achieving a conversion of oligomeric polyester of ≥ 99.5% and a selectivity for 1,4-butanediol of ≥ 98.0%.

[0023] The data in the examples show that the purity of bio-based 1,4-butanediol produced by the present invention is ≧99.5%, the feedstock conversion is ≧99.5%, and the selectivity for 1,4-butanediol is ≧98.0%. [Brief explanation of the drawings]

[0024] [Figure 1]1 is a flowchart of a method for producing bio-based 1,4-butanediol in an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] The present invention provides a method for producing bio-based 1,4-butanediol, A step of mixing bio-based succinic acid and an alcohol-based compound and subjecting them to an esterification reaction to obtain an oligomeric polyester; catalytically reducing the oligomeric polyester by hydrogenation to obtain crude 1,4-butanediol; and purifying the crude 1,4-butanediol to obtain the bio-based 1,4-butanediol.

[0026] In the present invention, unless otherwise specified, all raw materials used are commercially available products in this field. In the present invention, bio-based succinic acid and an alcohol compound are mixed and subjected to an esterification reaction to obtain an oligomeric polyester.

[0027] In the present invention, taking 1,4-butanediol as an example, the principle of the esterification reaction is as follows: JPEG0007779961000001.jpg63170n is 1, 2, 3, 4 or 5.

[0028] In the present invention, the bio-based succinic acid is preferably derived from biological fermentation, more preferably from starch fermentation or lignocellulose fermentation. After the fermentation, the succinic acid is preferably purified to obtain the succinic acid, which can be obtained by methods well known to those skilled in the art. The bio-based succinic acid has a wide range of sources and is renewable, which not only reduces carbon dioxide emissions, realizes the reuse of biomass energy, increases the added value of products, and reduces environmental pollution, but also brings about significant economic benefits.

[0029] In the present invention, the alcohol compound preferably comprises one or more of butanol, pentanol, hexanol, ethylene glycol, and 1,4-butanediol, and more preferably 1,4-butanediol. The esterification reaction of the succinic acid and the alcohol compound can be carried out without a catalyst, and after the esterification reaction is completed, there is no need for complicated post-treatment procedures such as post-treatment or catalyst separation. Furthermore, 1,4-butanediol has a high boiling point that is significantly different from the boiling point of water, and therefore can be separated together with water by distillation. This allows the water produced by the esterification reaction to be separated from the reaction system, allowing the esterification reaction to proceed smoothly. At the same time, because no other types of alcohol are introduced during the esterification process, the intermediate product does not need to be distilled or purified, and can be used in the following procedure.

[0030] In the present invention, the mass ratio of the bio-based succinic acid to the alcohol-based compound is preferably 10:11-16.

[0031] In the present invention, the esterification reaction temperature is preferably 160 to 210°C, more preferably 168 to 197°C, even more preferably 175 to 190°C, and most preferably 182°C, and the reaction time is preferably 5 to 7 hours.

[0032] In the present invention, during the esterification reaction process, the acid value is preferably controlled to be less than 10 mg KOH / g.

[0033] In the present invention, during the esterification reaction, it is preferred to take a sample to detect and analyze the acid value to determine the content of carboxylic acid. When the acid value is less than 10 mg KOH / g and the esterification demand index is reached, the esterification reaction is deemed to be essentially complete.

[0034] In the present invention, the method for analyzing the acid value preferably includes the following steps: 1. Reagents and test solutions 1.1 Absolute ethanol, 1.2 Potassium hydroxide ethanol standard solution [C(KOH) = 0.1 mol / L] 1.3 Phenolphthalein indicator: 1g / L ethanol solution 1.4 Neutral ethanol: Using phenolphthalein as an indicator and potassium hydroxide ethanol standard solution, add absolute ethanol dropwise until the color turns pale red. 2 Steps: Weigh out 20 g of sample (accurate to 0.0001 g) and place it in an Erlenmeyer flask. Add 50 mL of neutral ethanol, add 2-3 drops of phenolphthalein indicator, and add potassium hydroxide standard solution dropwise until the color turns pale red. The test is complete when the color does not disappear after 10 seconds. The acid value X1 (mgKOH / g) of BE01 is calculated by formula (1). JPEG0007779961000002.jpg39164Where: C: Concentration of potassium hydroxide-ethanol standard titration solution, unit is mol / L. V: Volume of potassium hydroxide-ethanol standard titration solution consumed by the titration sample, unit: mL. 56.1 is a constant. m: mass of the sample, in g.

[0035] In the present invention, the arithmetic mean value of the parallel measurement results is preferably used as the analysis result.

[0036] In the present invention, after the esterification reaction is completed, the resulting oligomeric polyester is preferably directly subjected to hydrogenation reduction without any post-treatment.

[0037] In the present invention, after obtaining an oligomeric polyester, the oligomeric polyester is hydrogenated and reduced in the presence of a catalyst to obtain crude 1,4-butanediol.

[0038] In the present invention, taking 1,4-butanediol as an example, the main reaction of the hydrogenation reduction is represented by the following formula: JPEG0007779961000003.jpg52170The side reaction is shown in the following equation: JPEG0007779961000004.jpg60170

[0039] In the present invention, the ratio of hydrogen to be used in the hydrogenation reduction to the hydrogen ester of the oligomeric polyester is preferably 80 to 200:1, and the hydrogen ester ratio refers to the molar ratio of hydrogen to the oligomeric polyester.

[0040] In the present invention, the pressure of the hydrogenation reduction is preferably 1 to 20 MPa, more preferably 8 to 18 MPa, even more preferably 10 to 16 MPa, and most preferably 12 to 14 MPa, the temperature is preferably 100 to 220°C, more preferably 160 to 210°C, even more preferably 170 to 200°C, and most preferably 180 to 190°C, and the time is preferably 2 to 6 hours, and more preferably 3 to 5 hours.

[0041] In the present invention, the mass ratio of the catalyst to the oligomeric polyester is 1:500-1000.

[0042] In the present invention, the catalyst is preferably a supported copper catalyst.

[0043] In the present invention, the supported copper catalyst is preferably (1) mixing copper nitrate hexahydrate, aluminum nitrate nonahydrate, an active metal salt, the metal of which may include magnesium, manganese, nickel, cobalt, zinc, cerium, or zirconium, and water to obtain a metal ion salt solution; Sodium hydroxide, sodium carbonate, and water are mixed to obtain an alkaline precipitant, and the molar ratio is [OH - ]=2([M 2+ ]+[M 3+ ]) and [CO 3- ]=0.5[M 3+ ], and M represents a metal element; (3) adding the metal ion salt solution and the alkaline precipitant to the reactor at 60°C to carry out the precipitation reaction, obtaining a precipitated product, and maintaining the pH of the reaction system at 8-10; Step (4) of aging the precipitated product at 70°C for 24 hours to obtain ternary hydrotalcite; and (5) sequentially roasting and activating the ternary hydrotalcite to obtain the supported copper catalyst.

[0044] In the present invention, the molar ratio of the copper nitrate hexahydrate, the metal in the active metal salt, and aluminum nitrate nonahydrate is preferably 1-5:1:0.25-2, more preferably 2-5:1:0.3-0.7.

[0045] In the present invention, the roasting temperature is preferably 400 to 800°C, more preferably 500 to 600°C, and the roasting time is preferably 0.5 to 8 hours, more preferably 2 to 4 hours.

[0046] In the present invention, the activation is preferably carried out in 5 vol% H2 / Ar.

[0047] In the present invention, the hydrogenation reduction is preferably carried out in a hydrogenation reactor, and the catalyst is preferably packed in a continuous reactor.

[0048] The present invention preferably uses a co-precipitation method to prepare a hydrotalcite-like precursor with a certain pH value, and then decomposes it by roasting to obtain the final active Cu-based catalyst. Because it is prepared by the co-precipitation method, the metal loading can be significantly increased compared to the conventional impregnation method. At the same time, by controlling the proportion of active metal and the roasting temperature, the surface morphology and physical and chemical properties of the supported copper-based catalyst can be changed. As a result, the catalyst has a high specific surface area, metal dispersion, suitable surface acidity and alkalinity, and Cu. + / Cu 0 Because of this ratio, the catalytic hydrogenation of oligomeric polyester using this catalyst can achieve lower hydrogenation pressure, lower hydrogenation temperature, and lower hydrogen ester ratio, while simultaneously improving the conversion rate of oligomeric polyester and the selectivity for 1,4-butanediol.

[0049] After the crude 1,4-butanediol is obtained, the present invention purifies the crude 1,4-butanediol to obtain the bio-based 1,4-butanediol.

[0050] In the present invention, the purification is preferably rectification purification, and the pressure of the rectification purification is preferably 8 to 25 mmHg, and the temperature of the rectification purification is preferably 140 to 190°C.

[0051] In the present invention, the rectification preferably also produces a low boiling fraction, which preferably contains n-butanol, water, tetrahydrofuran, etc., and is preferably used as a by-product solvent.

[0052] In the present invention, by-products of high boiling point components are preferably also obtained by the rectification purification.

[0053] To further illustrate the present invention, the method for producing bio-based 1,4-butanediol provided by the present invention is described in detail below with examples, which are not intended to limit the scope of protection of the present invention.

[0054] FIG. 1 is a flowchart of a method for producing bio-based 1,4-butanediol in accordance with an embodiment of the present invention.

[0055] The supported copper catalysts of Examples 1 to 7 of the present invention are Step (1) of mixing 2.4 moles of aluminum nitrate nonahydrate, 1 mole of aluminum nitrate nonahydrate, 0.6 moles of zinc nitrate hexahydrate, and 27.5 moles of water to obtain a mixed solution; Sodium hydroxide, sodium carbonate, and water are mixed to obtain an alkaline precipitant, and the molar ratio is [OH - ]=2([M 2+ ]+[M 3+ ]) and [CO 3- ]=0.5[M 3+ ], and M represents a metal element; (3) adding the metal ion salt solution and the alkaline precipitant to the reactor at 60°C to carry out the precipitation reaction, obtaining a precipitated product, and maintaining the pH of the reaction system at 8-10; Step (4) of aging the precipitated product at 70°C for 24 hours to obtain ternary hydrotalcite; The ternary hydrotalcite was sequentially roasted (500°C, 3 hours) and activated (5 vol% H 2 and (5) performing the step (in a nitrogen atmosphere) under 5000 K / Ar.

[0056] All succinic acids in Examples 1-7 are commercially available bio-based succinic acids.

[0057] Examples 1 to 7 The raw materials were weighed according to the raw material amounts in Table 1 and subjected to esterification reaction at the esterification reaction temperature shown in Table 1. The resulting oligomeric polyester was introduced into a hydrogenation reactor and directly subjected to hydrogenation reduction reaction. 1 ton of catalyst was reacted with 500 tons of oligomeric polyester. The hydrogenation reduction reaction parameters are shown in Table 1. Crude 1,4-butanediol was obtained, which was then purified by rectification at a pressure of 8 to 20 mmHg and a temperature of 140 to 190°C to obtain bio-based 1,4-butanediol.

[0058] As can be seen from Table 1, the present invention uses bio-based succinic acid and alcohol compounds as raw materials and produces the target product, bio-based 1,4-butanediol, through esterification and hydrogenation reduction. The purity of the produced bio-based 1,4-butanediol is ≥ 99.5%, the raw material conversion is ≥ 99.5%, and the selectivity for 1,4-butanediol is ≥ 98.0%.

[0059] Table 1. Reaction conditions, product purity, and batch yield of products in Examples 1 to 7 JPEG0007779961000005.jpg97170

[0060] Example 8 It is the same as Example 1, except that the roasting temperature in preparing the catalyst is 600°C.

[0061] Table 2. Reaction conditions, product purity, and batch yield of products for Examples 8 to 14 JPEG0007779961000006.jpg96170

[0062] As can be seen from Table 2, the present invention uses bio-based succinic acid and alcohol compounds as raw materials to produce the target product, bio-based 1,4-butanediol, through esterification and hydrogenation reduction. The obtained bio-based 1,4-butanediol had a purity of ≥ 99.1%, a raw material conversion rate of ≥ 99.5%, and a 1,4-butanediol selectivity of ≥ 97.8%.

[0063] Example 9 This is the same as Example 1, except that the amounts of raw materials used in preparing the catalyst are 2.7 mol of copper nitrate hexahydrate, 1 mol of aluminum nitrate nonahydrate, and 0.7 mol of zinc nitrate hexahydrate.

[0064] Table 3. Reaction conditions, product purity, and batch yield of products for Examples 15 to 21 JPEG0007779961000007.jpg86170

[0065] As can be seen from Table 3, the present invention uses bio-based succinic acid and alcohol compounds as raw materials and produces the target product, bio-based 1,4-butanediol, through esterification and hydrogenation reduction. The purity of the produced bio-based 1,4-butanediol was ≥ 99.1%, the raw material conversion rate was ≥ 99.5%, and the selectivity for 1,4-butanediol was ≥ 97.8%.

[0066] By comparing the data in Tables 1 to 3, it can be seen that the catalyst of the present invention has a high metal loading. By controlling the proportion of active metal and the roasting temperature, the surface morphology and physical and chemical properties of the supported copper catalyst can be changed. As a result, the catalyst has a high specific surface area, metal dispersion, suitable surface acidity and alkalinity, and Cu + / Cu 0Because of this ratio, catalytic hydrogenation of oligomeric polyester can achieve lower hydrogenation pressure, lower hydrogenation temperature, and lower hydrogen ester ratio, further improving the conversion rate of oligomeric polyester and the selectivity for 1,4-butanediol.

[0067] The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any way. It should be noted that those skilled in the art can make some improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be regarded as within the protection scope of the present invention.

Claims

1. 1. A method for producing bio-based 1,4-butanediol, comprising: A step of mixing bio-based succinic acid and an alcohol-based compound and subjecting them to an esterification reaction to obtain a diester or oligomeric polyester; catalytically reducing the diester or oligomeric polyester by hydrogenation to obtain crude 1,4-butanediol; and purifying the crude 1,4-butanediol to obtain the bio-based 1,4-butanediol; The ratio of hydrogen to hydrogen ester of the diester or oligomeric polyester used in the hydrogenation reduction is 80 to 200:1, and the catalyst is a supported copper catalyst. The supported copper catalyst is (1) Mixing copper nitrate hexahydrate, aluminum nitrate nonahydrate, an active metal salt selected from magnesium, manganese, nickel, cobalt, zinc, cerium, or zirconium, and water to obtain a metal ion salt solution; Step (2) of mixing sodium hydroxide, sodium carbonate, and water to obtain an alkaline precipitant; Step (3) of adding the metal ion salt solution and the alkaline precipitant into a reactor at 60°C to carry out a precipitation reaction to obtain a precipitated product, the molar ratio of which is [OH − ]=2([M 2+ ]+[M 3+ ]) and [CO 3 2− ]=0.5[M 3+ ], where M represents each metal element in step (1), and maintaining the pH of the reaction system at 8-10; Step (4) of aging the precipitated product at 70°C for 24 hours to obtain ternary hydrotalcite; (5) sequentially roasting and activating the ternary hydrotalcite to obtain the supported copper-based catalyst; the alcohol-based compound is selected from one or more of butanol, pentanol, hexanol, ethylene glycol, and 1,4-butanediol; The method is characterized in that the roasting temperature is 500 to 600°C and the roasting time is 0.5 to 8 hours.

2. 2. The method according to claim 1, wherein the molar ratio of the bio-based succinic acid to the alcohol-based compound is 1:1.2 to 2.

4.

3. 2. The method according to claim 1, wherein the esterification reaction is carried out at a temperature of 160 to 210° C. for 4 to 8 hours.

4. 2. The method according to claim 1, wherein the hydrogenation reduction is carried out at a pressure of 1 to 20 MPa, at a temperature of 100 to 220° C., and for 2 to 6 hours.

5. 2. The method according to claim 1, wherein the molar ratio of the copper nitrate hexahydrate, the metal in the active metal salt, and the aluminum nitrate nonahydrate is 1-5:1:0.25-2.

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