Method for producing biobased 1,4-butanediol

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, which can be used in the synthesis of pharmaceuticals and the preparation of advanced coatings, advanced inks, advanced resins, synthetic fibers rubbers, surfactants, etc.

[0003] At present, the main methods for producing 1,4-butanediol are the Reppe process, the maleic anhydride process, the allyl alcohol process, and the butadiene process. All of these traditional methods use petrochemical-based raw materials as raw materials. The Reppe process uses acetylene and formaldehyde as raw materials, first synthesizes 1,4-butynediol from acetylene and formaldehyde under the action of a copper-based catalyst, and then hydrogenates 1,4-butynediol to produce 1,4-butanediol. The Reppe process has the advantage of low operating costs, but because the acetylene partial pressure in the ethynylation stage process is too high, the process requires a high reactor design safety factor of 12 to 20, which significantly increases the initial equipment investment cost. At the same time, high acetylene partial pressure makes it easy to produce polyacetylene, which causes pipe blockage, reduces production efficiency, and is also easy to cause catalyst deactivation. Considering the shortcomings of the traditional Reppe process, the improved Reppe process is safer, requires less capital investment, and has a longer production cycle. The improved Reppe process is mainly divided into four processes: BASF, Dupont, IS, and Linde&SK. For example, Patent Document 1 discloses a comprehensive process for the continuous production of 1,4-butanediol, which includes a step (I) of reacting formaldehyde with acetylene in the presence of a copper catalyst at a pH value of 5-8, with a molar ratio of formaldehyde to acetylene of up to 2:1, a step (II) of subjecting the resulting aqueous mixture containing butynediol to intermediate buffering for 0.1-100 hours, a step (III) of hydrogenating the mixture obtained after intermediate buffering, and a step (IV) of distilling the hydrogenation product obtained in step III to obtain 1,4-butanediol, and Patent Document 2 discloses a process for the production of butanediol by two-step hydrogenation of butynediol. In the current production of butanediol by two-stage hydrogenation from butynediol, considering the requirements of adaptability to the reaction system containing water, the fluctuation of the water content in the reaction system, and the suppression of the formation of carbon deposits, the two-stage hydrogenation catalysts A and B contain a carrier, a metal active component, and a silane group, and the silane group is grafted by silylation treatment, among which the silane group is considered to account for 0.1wt% to 12wt% of the total weight of the hydrogenation catalyst. Compared with the prior art, the activity and selectivity of the hydrogenation catalyst are better, and the applicability of the raw material is obvious. The presence of water has little effect on the catalytic performance of the hydrogenation catalyst, and at the same time, the formation of carbon deposits on the catalyst surface can be greatly suppressed, the service life of the catalyst can be extended, and the operation cycle of the hydrogenation reaction system is long and stable. 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 is mainly to produce formaldehyde through the action of catalyst using the raw materials methanol and air; the acetylenization stage is mainly to make acetylene and formaldehyde react with each other under the action of catalyst to produce refined 1,4-butynediol; the hydrogenation stage is mainly to use 1,4-butynediol and hydrogen from the upstream furnace gas purification stage under a certain pressure to produce crude 1,4-butanediol through the action of catalyst; the product rectification stage is mainly to rectify 1,4-butanediol to obtain high-purity 1,4-butanediol product.

[0004] In the butadiene process, butadiene is converted to 1,4-diacetoxy-2-butene through acetyl oxidation, 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 to the target product and the flexibility to control the ratio of tetrahydrofuran to 1,4-butanediol, but it also has the disadvantages of 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 in the presence of a hydrogenation catalyst, hydrogen reacts with the 1,4-diacetoxybutene to obtain 1,4-diacetoxybutane, and the 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 contains a Pt element and a promoter element, and the promoter element is 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 the group of metalloid metals and group VIIB metals.

[0005] In the allyl alcohol method, allyl alcohol is first produced by isomerization of propylene oxide, and allyl alcohol is hydroformylated in liquid phase using aromatic hydrocarbon as solvent and rhodium catalyst and triphenylphosphorus solution as catalyst to produce 4-hydroxybutyraldehyde solution, which is then hydrogenated under the action of Raney nickel catalyst to produce 1,4-butanediol.The process of this method uses rare precious metals, so it is expensive and not environmentally friendly, and has the disadvantages of low product selectivity and large amount of by-products. For example, U.S. Patent No. 6,363,933 discloses using synthesis gas to hydroformylate allyl alcohol in an allyl alcohol feedstock to produce a hydroformylation product comprising 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 comprising 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 and tetrahydrofuran as a by-product. This process has the disadvantages of high raw material costs and large capital investments. For example, in Patent Document 7, the maleic anhydride production process and the BDO production process are combined to save the original equipment and energy consumption for rich oil analysis and solvent treatment in the n-butane maleic anhydride unit, impurities generated in the maleic anhydride unit are removed together with impurities in the BDO unit, and therefore the unit costs are saved. When butanol is used as a raw material for maleic anhydride esterification to produce dibutyl maleate (DBM), the by-product butanol 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 application. The present invention uses succinic acid derived from bio-based material as 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 objectives, 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, 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 oligomer polyester is 80 to 200:1.

[0016] Preferably, the hydrogenation reduction is carried out under a pressure of 1 to 20 MPa at a temperature of 100 to 220° C. for a period of 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+ ], wherein M represents a metal element; and (3) adding the metal ion salt solution and the alkaline precipitant to a reactor at 60°C respectively to carry out a precipitation reaction, obtain a precipitation product, and maintain the pH of the reaction system at 8-10; (4) aging the precipitation product at 70° C. for 24 hours to obtain a 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 oligomeric polyester, hydrogenating the oligomeric polyester under a catalyst to obtain crude 1,4-butanediol, and purifying the crude 1,4-butanediol to obtain the bio-based 1,4-butanediol. Effect 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 from biological fermentation, and the raw material source is wide and 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 about significant economic benefits. Furthermore, the alcohol-based 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-based 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 and catalyst separation. In addition, 1,4-butanediol has a high boiling point, which is significantly different from the boiling point of water, and can be separated together with water by distillation, so that the water generated by the esterification reaction can be separated from the reaction system, allowing the esterification reaction to proceed smoothly, and at the same time, since 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. In addition, in the present invention, the supported copper-based 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-based catalyst. Since it is prepared by coprecipitation, the metal loading can be greatly improved compared with the traditional impregnation method. At the same time, the surface morphology and physical and chemical properties of the supported copper-based catalyst can be changed by controlling the proportion of active metals and the roasting temperature, so that the catalyst has 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 by this catalyst can achieve a lower hydrogenation pressure (1-20 MPa), a lower hydrogenation temperature (100-220°C), and a lower hydrogen ester ratio (hydrogen ester ratio 80-200:1), while the conversion of oligomeric polyester is ≧99.5%, and the selectivity of 1,4-butanediol is ≧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 feed conversion is ≧99.5%, and the selectivity of 1,4-butanediol is ≧98.0%. [Brief description of the drawings]

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

[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 the raw materials used are commercially available products in this field. In the present invention, succinic acid derived from a bio-based material is mixed with an alcohol-based compound 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: JPEG2025024699000002.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, and the present invention provides the succinic acid obtained after the fermentation, preferably by purification, using methods well known to those skilled in the art, and 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 great economic benefits.

[0029] In the present invention, the alcohol-based compound preferably includes 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-based 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 and catalyst separation. In addition, 1,4-butanediol has a high boiling point, which is significantly different from the boiling point of water, and can be separated together with water by distillation. Therefore, the water generated by the esterification reaction can be separated from the reaction system, and the esterification reaction can proceed smoothly. At the same time, since no other types of alcohol are introduced during the esterification process, the intermediate product does not need to be distilled and 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., further 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 process of the esterification reaction, the acid value is preferably controlled to be less than 10 mg KOH / g.

[0033] In the present invention, in the process of the esterification reaction, a sample is preferably taken to detect and analyze the acid value, and the content of carboxylic acid is detected. 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 completed.

[0034] In the present invention, the method for analyzing the acid value preferably includes the following steps. 1 Reagents and 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) into an Erlenmeyer flask, add 50 mL of neutral ethanol, add 2-3 drops of phenolphthalein indicator, and drip the potassium hydroxide standard solution until the color turns pale red. The test is complete when the color does not disappear within 10 seconds. The acid value X1 (mgKOH / g) of BE01 is calculated by formula (1). JPEG2025024699000003.jpg39164Where: C: Concentration of the potassium hydroxide-ethanol standard titration solution, in mol / L. V: Volume of potassium hydroxide-ethanol standard titration solution consumed by the titration sample, unit is mL. 56.1 is a constant. m: mass of the sample, in g.

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

[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: JPEG2025024699000004.jpg52170The side reaction is shown in the following equation. JPEG2025024699000005.jpg60170

[0039] In the present invention, the ratio of hydrogen used in the hydrogenation reduction to the hydrogen ester of the oligomer polyester is preferably 80 to 200:1, and the hydrogen ester ratio refers to the molar ratio of hydrogen to the oligomer 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 oligomer polyester is 1:500-1000.

[0042] In the present invention, the catalyst is preferably a supported copper-based 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+ ], wherein M represents a metal element; and (3) adding the metal ion salt solution and the alkaline precipitant to a reactor at 60°C respectively to carry out a precipitation reaction, obtain a precipitation product, and maintain the pH of the reaction system at 8-10; (4) aging the precipitation product at 70° C. for 24 hours to obtain a ternary hydrotalcite; and (5) sequentially roasting and activating the ternary hydrotalcite to obtain the supported copper-based 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, and 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 prepares a hydrotalcite-like precursor by co-precipitation method with a certain pH value, and then decomposes it by roasting to obtain a final active Cu-based catalyst. Since it is prepared by co-precipitation method, the metal loading amount can be greatly increased compared with the traditional 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, so that the catalyst has high specific surface area, metal dispersion, suitable surface acidity and alkalinity and Cu. + / Cu 0 Due to the above ratio, the catalytic hydrogenation of oligomeric polyester by the catalyst can achieve lower hydrogenation pressure, lower hydrogenation temperature, and lower hydrogen ester ratio, while improving the conversion rate of oligomeric polyester and the selectivity of 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, the pressure of the rectification is preferably 8 to 25 mmHg, and the temperature of the rectification is preferably 140 to 190°C.

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

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

[0053] In order 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 reference to examples, which are not intended to limit the scope of the present invention.

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

[0055] The supported copper catalysts of Examples 1 to 7 of the present invention are (1) mixing 2.4 mol of aluminum nitrate nonahydrate, 1 mol of aluminum nitrate nonahydrate, 0.6 mol of zinc nitrate hexahydrate, and 27.5 mol 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+ ], wherein M represents a metal element; and (3) adding the metal ion salt solution and the alkaline precipitant to a reactor at 60°C respectively to carry out a precipitation reaction, obtain a precipitation product, and maintain the pH of the reaction system at 8-10; (4) aging the precipitated product at 70° C. for 24 hours to obtain a ternary hydrotalcite; The ternary hydrotalcite was sequentially roasted (500°C, 3 h) and activated (5 vol% H 2 / 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 esterification reaction was carried out. The temperature of the esterification reaction was shown in Table 1. The obtained oligomeric polyester was introduced into a hydrogenation reactor and directly carried out hydrogenation reduction reaction. 1 ton of catalyst feed reacted with 500 tons of oligomeric polyester. The parameters of the hydrogenation reduction reaction were shown in Table 1. Crude 1,4-butanediol was obtained, and then rectification purification was carried out at a pressure of 8-20 mmHg and a temperature of 140-190 °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 rate is ≧99.5%, and the selectivity of 1,4-butanediol is ≧98.0%.

[0059] Table 1. Reaction conditions, product purity, and batch yield of products in Examples 1 to 7 JPEG2025024699000006.jpg97170

[0060] Example 8 Similar to Example 1, the only difference is that the roasting temperature in preparing the catalyst is 600°C.

[0061] Table 2. Reaction conditions, product purity, and product batch yields for Examples 8 to 14. JPEG2025024699000007.jpg96170

[0062] As can be seen from Table 2, 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 obtained bio-based 1,4-butanediol has 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 similar to Example 1, but the difference is 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 JPEG2025024699000008.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 is ≧99.1%, the raw material conversion rate is ≧99.5%, and the selectivity of 1,4-butanediol is ≧97.8%.

[0066] And 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, and 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, so that the catalyst has a high specific surface area, metal dispersion, suitable surface acidity and alkalinity, and Cu + / Cu 0Due to the above ratio, the catalytic hydrogenation of oligomeric polyester can achieve lower hydrogenation pressure, lower hydrogenation temperature, and lower hydrogen ester ratio, and further improve the conversion rate of oligomeric polyester and the selectivity of 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 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 an oligomeric polyester; hydrogenating the oligomeric polyester under catalytic conditions 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 the hydrogen ester of the 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; (2) mixing sodium hydroxide, sodium carbonate, and water to obtain an alkaline precipitant; (3) adding the metal ion salt solution and the alkaline precipitant to a reactor at 60° C. respectively to carry out a precipitation reaction, obtain a precipitation product, and maintain the pH of the reaction system at 8-10; (4) aging the precipitation product at 70° C. for 24 hours to obtain a ternary hydrotalcite; (5) sequentially roasting and activating the ternary hydrotalcite to obtain the supported copper-based catalyst; 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 alcohol-based compound is selected from the group consisting of butanol, pentanol, hexanol, ethylene glycol, and 1,4-butanediol.

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

4.

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

5. 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 a time of 2 to 6 hours.

6. 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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