Preparation method of malonic acid
3-hydroxypropionic acid is synthesized by biocatalytic biocatalyzing of bioglycerol and chemical catalysis using supported catalysts, which solves the problems of low efficiency and pollution in the existing malonate preparation process, and achieves low-cost and low-temperature malonate preparation , improves the safety of the process and product value.
Patent Information
- Application Number
- CN202411204839.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-29
- Publication Date
- 2024-12-10
AI Technical Summary
The existing malon acid preparation process has problems such as low efficiency, heavy pollution of the environment, complex purification steps and high raw material costs, and the industrial production of bio-based products is limited by strains and cost restrictions.
Malonic acid is prepared by biocatalyzing biocatalytic using bioglycerol, and a chemical catalyst supported by an active metal component is oxidized at 50-100°C. The method includes combining biocatalysis and chemical catalysis, and catalytic reactions are carried out using a supported catalyst such as Au/Cu/TiO2, etc.
Malon acid preparation with low raw material cost, low reaction temperature, simple reaction process and high safety is achieved, which improves the safety of the process and the added value of glycerol, and the conversion rate and selectivity reach 85% or more.
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Abstract
Description
Technical Field
[0001] The invention belongs to the field of biocatalysis and chemical catalysis, and relates to a method for preparing malonic acid, specifically to a method for preparing malonic acid from 3-hydroxypropionic acid, and particularly to a method for synthesizing 3-hydroxypropionic acid from glycerol through biocatalysis, and then synthesizing malonic acid from 3-hydroxypropionic acid through chemical catalysis. Background Art
[0002] Malonic acid, also known as carrot acid, is a very important dicarboxylic acid, which is widely used in many fields, and its esters can be used as basic organic synthetic materials for dyes and drugs. At present, malonic acid is mainly produced by chemical methods using non-renewable petroleum raw materials. Malonic acid is commonly prepared by hydrolyzing cyanoacetic acid or diethyl malonate in industry; it can also be prepared from acetic acid as a raw material, including: acetic acid reacts with chlorine to obtain chloroacetic acid, then treats with sodium carbonate to generate sodium salt, and undergoes nucleophilic substitution reaction with sodium cyanide to obtain cyanoacetic acid, which is hydrolyzed with sodium hydroxide solution, and the cyano group is converted into a carboxylate ion, and then acidified to obtain malonic acid. However, the above preparation process has the problems of low efficiency, heavy environmental pollution and complicated purification steps. Yan Jinghong et al. reported a reaction route (CN116120162A) for preparing malonic acid by catalyzing the hydrolysis of dimethyl malonate using a specific solid superacid prepared from a resin raw material, which can replace inorganic acid catalysis, avoid the problem of equipment corrosion, and is pollution-free and low cost. It can be seen that the existing chemical technology route faces huge environmental and price problems in actual industrial production, and has problems such as low efficiency, environmental pollution and complex purification steps. Therefore, the development of a green, safe and environmentally friendly new process for malonic acid is an urgent need of the industry.
[0003] In addition, the international and domestic demand and requirements for bio-based green products are increasing. Biomanufacturing of high value-added compounds has become a potential alternative to the traditional petrochemical industry. Replacing petroleum-based malonic acid with bio-based malonic acid can better meet the international and domestic requirements for green and environmentally friendly products and improve product value. For example, Deng Yu et al. reported the use of a recombinant Escherichia coli that produces malonic acid to construct a full biosynthetic pathway for malonic acid (CN113122486B), however, this synthetic pathway is limited by strains and production costs. In addition, the amount of by-product accumulation in this route is very high, resulting in a large loss of carbon sources, which is not conducive to achieving industrial production. Therefore, it is still necessary to develop an environmentally friendly, economical and efficient malonic acid production route. Summary of the invention
[0004] In view of the shortcomings of existing processes and the requirements of green and environmentally friendly bio-based products, the present invention develops a green process route for preparing bio-based malonic acid by combining bio-conversion and chemical conversion of bio-based glycerol, providing a new idea for the green production of malonic acid.
[0005] The main purpose of the present invention is to provide a method for synthesizing malonic acid from 3-hydroxypropionic acid through chemical catalysis, aiming to solve the many deficiencies and technical defects in the existing malonic acid preparation process.
[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:
[0007] The present invention provides a method for preparing malonic acid, the preparation method comprising:
[0008] 3-Hydroxypropionic acid undergoes oxidation reaction at 50-100°C in an oxygen-containing atmosphere and a chemical catalyst to obtain malonic acid;
[0009] The reaction route is:
[0010]
[0011] Wherein, the chemical catalyst is a supported catalyst with an active metal component supported on an oxide support;
[0012] The oxide support is selected from TiO 2 、CeO 2 、ZrO 2 , Fe 2 O 3 、SiO 2 The active metal component is one or more selected from Pd, Pt, Cu, and Au.
[0013] According to the present invention, the supported catalyst is one or more (for example, two) active metal components selected from Pd, Pt, Cu, and Au supported on a substrate selected from TiO 2 、CeO 2 、ZrO 2 、Fe2O 3 、SiO 2 A metal-supported catalyst prepared on one or more (for example, two) oxide supports.
[0014] In some embodiments, the oxygen content in the oxygen-containing atmosphere is 5-80%, such as air.
[0015] In some embodiments, in the chemical catalyst, the active metal component supported by the oxide carrier is preferably selected from one or more of Pd, Cu, and Au, more preferably Au and Cu.
[0016] In some embodiments, in the chemical catalyst, the loading amount of the active metal component is 0.2-5wt% of the oxide support, preferably 0.5-3wt%, such as 0.5wt%, 1wt%, 2wt%.
[0017] More specifically, the chemical catalyst may be selected from one or more of the following catalysts: Au / TiO with Au loading of 0.5 wt%, 1 wt%, 2 wt% or 2.5 wt% respectively. 2 、Au / CeO 2 、Au / Fe 2 O 3 Catalyst: Pd / CeO with Pd loading of 0.5wt%, 1wt% or 2wt% 2 、Pd / ZrO 2 Catalyst: Pt / TiO with Pt loading of 0.5wt% or 1wt% 2 、Pt / SiO 2 Catalyst: Cu / TiO with Cu loading of 0.2wt%, 0.3wt%, 0.5wt% or 2.5wt% 2 、Cu / CeO 2 、Cu / Fe 2 O 3 Catalyst: PdCu / TiO with 1wt% Pd loading and 1wt% Cu loading 2 Catalyst: PtCu / TiO with 1wt% Pt loading and 1wt% Cu loading 2 Catalyst: AuCu / TiO with 2wt% Au loading and 0.5wt% Cu loading 2 catalyst;
[0018] In particular, the chemical catalyst is AuCu / TiO with an Au loading of 2 wt% and a Cu loading of 0.5 wt%. 2 Catalyst; the above percentages are the mass percentages of the corresponding metals in the catalyst based on the carrier.
[0019] In some embodiments, the chemical catalyst can be prepared by an impregnation method, for example:
[0020] Method 1: A method for preparing a catalyst in which an oxide carrier alone carries Cu, comprising the following steps: impregnating the oxide carrier in an aqueous solution of copper nitrate, and then drying to obtain a catalyst precursor; calcining the catalyst precursor at 350-500° C. in an oxidizing atmosphere to obtain the chemical catalyst.
[0021] Method 2: A method for preparing a catalyst of Pd, Pt or Au loaded on an oxide carrier, comprising the following steps: impregnating the oxide carrier in an aqueous solution of a soluble acid or salt of the active metal, and then drying to obtain a catalyst precursor; reducing the catalyst precursor in a reducing atmosphere at 200-380°C to obtain the chemical catalyst.
[0022] Method 3: Preparation of a co-supported catalyst (an oxide support supports a plurality of Pd, Pt, Au or Cu): the oxide support is immersed in an aqueous solution of a soluble acid or salt of the active metal, and then dried to obtain a catalyst precursor; the catalyst precursor is heated in N 2 The chemical catalyst is obtained by calcining at 300-500° C. in a reducing atmosphere and then reducing at 250-350° C. in a reducing atmosphere.
[0023] In some embodiments, the soluble acid or salt of the active metal is selected from H 2 PdCl 6 , H 2 PtCl 6 、Cu(NO 3 ) 2 and HAuCl 4 , and one or more of their hydrates. The concentration of the active metal in the aqueous solution of the soluble acid or salt of the active metal is 20-50wt%, preferably 25-40wt%.
[0024] In some embodiments, the impregnation may be performed under stirring, and the impregnation time is 5-15 hours, preferably 7-10 hours.
[0025] In some embodiments, the drying step may be: first evaporating the solvent, and then drying at 90-120° C. (eg, 100° C.) for 5-15 hours.
[0026] In some embodiments, the reducing atmosphere is an H2 / N2 atmosphere, particularly an atmosphere in which the hydrogen content is 10-30%, preferably an atmosphere in which the hydrogen content is 20%.
[0027] In some embodiments, the reduction is preferably carried out at 250-350°C (eg, 250°C, 270°C, 280°C, 300°C, 310°C, 330°C, 350°C); the reduction time is 1-6h, more preferably 2-4h.
[0028] In some embodiments, the mass ratio of the active metal component of the chemical catalyst to 3-hydroxypropionic acid is 0.00001-0.001:1, preferably 0.00005-0.0005:1.
[0029] In some embodiments, the temperature of the chemical catalytic reaction can be 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, preferably 60-90°C; the reaction time can be 1-6 hours, specifically 1 hour, 2 hours, 3 hours, 4 hours, 5 hours or 6 hours.
[0030] In some embodiments, the chemical catalytic reaction can be carried out in the presence of a base, and the base can be selected from NaOH, KOH, Ca(OH) 2 One or more of, preferably Ca(OH) 2 ; In the reaction system, the concentration of the base can be 0.003 to 0.015 mol / L, specifically 0.003 mol / L, 0.007 mol / L, 0.012 mol / L, 0.015 mol / L, preferably 0.007 to 0.008 mol / L.
[0031] In the chemical catalytic reaction of the present invention, the conversion rate of 3-hydroxypropionic acid can reach up to about 85%, the selectivity of malonic acid can reach up to about 70%, and the yield can reach up to more than 58%.
[0032] In some embodiments, the 3-hydroxypropionic acid can be prepared by a biocatalytic method, the biocatalytic method comprising:
[0033] In a polar solvent, glycerol undergoes a continuous dehydration-oxidation reaction under the action of air atmosphere and enzyme catalyst to obtain 3-hydroxypropionic acid;
[0034] The reaction route is as follows:
[0035]
[0036] Wherein, the enzyme catalyst includes dehydratase, coenzyme NAD + and aldehyde dehydrogenase;
[0037] The dehydratase is selected from glycerol dehydratase, arabinose dehydratase, gluconate dehydratase and a mixed enzyme of two or more of the above enzymes, and is preferably glycerol dehydratase.
[0038] In some embodiments, the polar solvent may be water, methanol, ethanol or a combination thereof, preferably water.
[0039] In the biocatalytic preparation method of 3-hydroxypropionic acid, first, glycerol is catalyzed by dehydratase to generate 3-hydroxypropanal, and then aldehyde dehydrogenase and coenzyme NAD + Further catalysis produces 3-hydroxypropionic acid and one molecule of NADH.
[0040] In some embodiments, the dehydratase, coenzyme NAD + The aldehyde dehydrogenase and aldehyde dehydrogenase can be added simultaneously or in batches, that is, the dehydratase is first added to the reaction system, and then the aldehyde dehydrogenase and coenzyme NAD are added. + .
[0041] In some embodiments, the glycerol may be bio-based glycerol, which refers to a natural glycerol produced by utilizing biomass resources (such as animal and plant oils), the main source of which is a by-product of the biodiesel industry, and is an important biomass-based platform compound.
[0042] In some embodiments, in the continuous dehydration-oxidation reaction, the glycerol concentration may be 100-200 g / L, preferably 150 g / L.
[0043] In some embodiments, the mass ratio of glycerol to dehydratase is 5:(1-10), preferably 5:(1-8), such as 5:4.
[0044] In some embodiments, the mass ratio of glycerol to aldehyde dehydrogenase and coenzyme NAD+ is 5:(1-10):(1-5), preferably 5:(1-6):(1-4), for example 5:3:2.
[0045] In some embodiments, the pressure of the continuous dehydration-oxidation reaction may be 15-35 atm, preferably 20 atm.
[0046] In some embodiments, the temperature of the continuous dehydration-oxidation reaction may be 20-40°C, preferably 30-37°C, and more preferably 35°C.
[0047] In some embodiments, the continuous dehydration-oxidation reaction time may be 5-25 hours, preferably 8-16 hours.
[0048] In some embodiments, the biocatalytic method of 3-hydroxypropionic acid further includes separation and purification, specifically, using ion exchange resin as an adsorbent to enrich and separate 3-hydroxypropionic acid in the reaction solution to obtain a 3-hydroxypropionic acid enriched solution; the ion exchange resin is a weakly basic anion exchange resin, and its eluent is a 0.03 mol / L NaOH aqueous solution. Further, 4-10 wt%, w / v, for example 6%, w / v activated carbon powder is added to the 3-hydroxypropionic acid enriched solution for decolorization.
[0049] In some embodiments, the 3-hydroxypropionic acid can be prepared by the following process: adding glycerol, glycerol dehydratase and coenzyme NAD into an aqueous solution. + The reaction is carried out in an air atmosphere, and then aldehyde dehydrogenase is added, and the reaction is continued to obtain a reaction solution containing 3-hydroxypropionic acid, which is separated and purified.
[0050] In the biocatalytic preparation method of 3-hydroxypropionic acid, the conversion rate of glycerol can reach up to about 85%, the selectivity of 3-hydroxypropionic acid can reach up to about 80%, and the yield of 3-hydroxypropionic acid can reach up to about 65%.
[0051] Compared with the prior art, the method of the present invention has the following beneficial effects:
[0052] 1) Compared with the existing chemical preparation route of malonic acid, this route has the advantages of low raw material cost, low reaction temperature, simple reaction process and high safety;
[0053] 2) The patent of this invention uses glycerol as raw material, which is non-toxic and harmless to the human body, safe for the environment, and stable in nature, which greatly improves the safety of the process and increases the added value of glycerol; BRIEF DESCRIPTION OF THE DRAWINGS
[0054] Figure 1 The 2% Au0.5% Cu / TiO obtained in Example 2 of the present invention 2 Scanning electron microscopy image of the catalyst. DETAILED DESCRIPTION
[0055] As mentioned above, in view of the many defects of the prior art, the inventor of this case has proposed the technical solution of the present invention after long-term in-depth research and extensive practice, which is described in detail below.
[0056] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods; the reagents, materials, etc. used in the following examples, unless otherwise specified, can be obtained from commercial channels.
[0057] Glycerol: crude glycerol produced as a byproduct of biodiesel, purchased from Longyan Excellent Bio-based Materials Co., Ltd., and used after purification. The purification method refers to patent CN114014746B;
[0058] Ion exchange resin: weak base type, purchased from Anhui Sanxing Resin Co., Ltd.;
[0059] Glycerol dehydratase: purchased from Sigma-Aldrich, product number: C7025;
[0060] Coenzyme NAD + : Purchased from Sigma-Aldrich, product number: N7132;
[0061] Aldehyde dehydrogenase: purchased from Sigma-Aldrich, product number: 1.15640;
[0062] H 2 PdCl 6 Aqueous solution: purchased from Shaanxi Kaida Chemical Co., Ltd., with a Pd content of 27 wt%;
[0063] H 2 PtCl 6 6H 2 O aqueous solution: purchased from Shaanxi Kaida Chemical Co., Ltd., Pt content ≥ 38wt%;
[0064] Cu(NO 3 )2: purchased from Bailingwei Technology Co., Ltd., Cu content ≈ 34wt%;
[0065] HAuCl 4 Aqueous solution: purchased from Shaanxi Kaida Chemical Co., Ltd., Au content ≥ 50wt%;
[0066] TiO 2 、CeO 2 、ZrO 2 , Fe 2 O 3 、SiO 2 The products in the following examples were detected by filtering the reaction solution and the catalyst, and then analyzing and quantifying them by high performance liquid chromatography (Shimadazu LC-20A HPLC; separation column: Inertsil ODS-SPC 18 Column; analysis conditions: mobile phase is water, phosphoric acid and methanol with a volume ratio of 950.0:0.5:50.0, column temperature: 30°C, detector: UV 210nm, flow rate: 0.8mL / min, injection volume: 20μL). Under this condition, the retention time of glycerol is 4.0min, the retention time of glyceraldehyde is 4.3min, the retention time of glyceric acid is 4.6min, the retention time of 3-hydroxypropionic acid is 5.0min, the retention time of 3-hydroxypropanal is 4.8min, and the retention time of malonic acid is 6.3min.
[0067] The technical solution of the present invention is further described below in conjunction with several embodiments.
[0068] For enzyme-catalyzed reactions:
[0069] Glycerol conversion rate = [converted glycerol mass ÷ fed glycerol mass] x 100%
[0070] Among them, the mass of converted glycerol = the mass of glycerol input - the mass of glycerol remaining
[0071] 3-Hydroxypropionic acid selectivity (selectivity is defined as the ratio of the molar amount of product to the molar amount of converted raw material expressed in the same unit) = [(mass of 3-hydroxypropionic acid ÷ 90.08) ÷ (mass of glycerol ÷ 92.09)] x 100%
[0072] 3-Hydroxypropionic acid yield = glycerol conversion x 3-Hydroxypropionic acid selectivity = [(mass of 3-hydroxypropionic acid ÷ 90.08) ÷ (mass of converted glycerol ÷ 92.09)] x 100%
[0073] For chemical catalysis reactions:
[0074] 3-Hydroxypropionic acid conversion rate = [mass of converted 3-hydroxypropionic acid / mass of 3-hydroxypropionic acid fed] x 100%
[0075] Malonic acid selectivity = [(mass of malonic acid ÷ 104.06) ÷ (mass of 3-hydroxypropionic acid ÷ 90.08)] x 100%
[0076] Malonic acid yield = 3-hydroxypropionic acid conversion rate x malonic acid selectivity = [(mass of malonic acid ÷ 104.06) ÷ (mass of converted 3-hydroxypropionic acid ÷ 90.08)] x 100%
[0077] Example 1: Process for preparing 3-hydroxypropionic acid by enzyme-catalyzed dehydration and oxidation of glycerol
[0078]
[0079] 120 g / L of glycerol dehydratase was added to a 150 g / L glycerol aqueous solution. The reaction was carried out in an air atmosphere of 20 atm at a temperature of 35°C. After 4 hours of reaction, 90 g / L of aldehyde dehydrogenase and 60 g / L of coenzyme NAD were added. + The reaction was continued for 4 hours to obtain a reaction solution containing 3-hydroxypropionic acid, which was separated and purified by ion exchange resin at 0.05 mol / L -1 The product was eluted with an aqueous sodium hydroxide solution, and the eluate was adjusted to neutral with formic acid or acetic acid, and then 5% (w / v) activated carbon powder was added for decolorization. The concentration of the obtained 3-hydroxypropionic acid was detected by high performance liquid chromatography. The glycerol conversion rate was calculated to be 80.3% and the 3-hydroxypropionic acid selectivity was 73.4% according to the above method.
[0080] In addition, based on the above reaction method, different conditions were used to carry out enzyme-catalyzed glycerol dehydration oxidation to prepare 3-hydroxypropionic acid. The settings of different reaction conditions and the results of glycerol conversion and 3-hydroxypropionic acid selectivity are shown in Table 1.
[0081] Table 1. Enzymatic production of 3-hydroxypropionic acid from glycerol under different conditions
[0082]
[0083]
[0084] Example 2: Preparation of chemical catalyst
[0085] The oxide carrier involved in this embodiment includes TiO 2 (Anatase crystal form, specific surface area 164m 2 ·g -1 )、CeO2 、ZrO 2 , Fe 2 O 3 The carrier used was first calcined at 300°C for 3h and then placed in a desiccator for later use.
[0086] The catalyst of Cu supported on oxide carrier is prepared by impregnation method, and the specific steps are as follows:
[0087] A certain amount of oxide support (TiO 2 、CeO 2 or Fe 2 O 3 ) was added to a copper nitrate aqueous solution (the amount of copper added in the reaction system was controlled to be 0.5wt% or 1wt% of the oxide support), stirred for 8h, and then the solvent was evaporated on a rotary evaporator and dried in an oven at 120°C overnight to obtain a catalyst precursor. 2 Atmosphere (flow rate 45 mL min -1 ) and calcined at 450℃ for 3h. The corresponding 1%Cu / TiO 2 、0.5%Cu / Fe 2 O 3 、0.5%Cu / CeO 2 Catalyst (the percentage is the mass percentage of the corresponding metal in the catalyst to the carrier).
[0088] The catalyst loaded with Pd, Pt or Au on an oxide support is prepared by an impregnation method, the specific steps are as follows:
[0089] A certain amount of single oxide support (TiO 2 、CeO 2 、ZrO 2 , Fe 2 O 3 or SiO 2 ) added to H 2 PdCl 6 , H 2 PtCl 6 6H 2 O or HAuCl 4 The catalyst precursor was prepared by stirring the catalyst precursor in 20% H 2 / N 2 Atmosphere (flow rate 35mL·min -1 ) and reduced at 300℃ for 3h. The corresponding 1% Pd / CeO 2、0.5%Pd / ZrO 2 、1%Pd / ZrO 2 、2%Pd / CeO 2 、1%Pt / SiO 2 , 0.5%Au / TiO 2 、1%Au / CeO 2 、0.5%Au / Fe 2 O 3 Catalyst (the percentage is the mass percentage of the corresponding metal in the catalyst to the carrier).
[0090] The catalyst of Cu and precious metal (Au, Pd) co-loaded on the oxide carrier is prepared by impregnation method, and the specific steps are as follows:
[0091] A certain amount of oxide support (TiO 2 ) was added to a certain amount of Cu(NO 3 ) 2 and HAuCl 4 , H 2 PdCl 6 or H 2 PtCl 6 6H 2 O aqueous solution (the amount of each metal added in the reaction system is controlled to be 0.5wt%, 1wt% or 2wt% of the oxide support), stirred for 8h, then the solvent was evaporated on a rotary evaporator, and dried in an oven at 120°C for 8h to obtain a catalyst precursor. The catalyst precursor was 2 (Flow rate: 35 mL min -1 ) was calcined at 400 °C for 3 h and then heated in 20% H 2 / N 2 Air flow (flow rate 35mL·min -1 ) and reduced at 300℃ for 2h. The corresponding 2%Au0.5%Cu / TiO 2 、1%Pd1%Cu / TiO 2 Catalyst (the percentage is the mass percentage of the corresponding metal in the catalyst to the carrier). Among them, 2% Au 0.5% Cu / TiO 2 The scanning electron microscopy image of the catalyst is shown in Figure 1 shown.
[0092] Example 3: Process for preparing malonic acid from 3-hydroxypropionic acid by chemical catalysis
[0093]
[0094] 50 mmol of 3-hydroxypropionic acid obtained in Example 1 was placed in a 100 mL reaction kettle filled with sufficient water (30 mL), and 0.2 g of 2% Au 0.5% Cu / TiO prepared in Example 2 was added. 2 catalyst, add 2mL of 0.2mol / L NaOH solution, and fill with N 2 The pressure in the reactor was set to 20 atm, heated to 70°C, and reacted for 3 hours. The conversion rate of 3-hydroxypropionic acid was calculated to be 81.5%, and the selectivity of malonic acid was 63.3%.
[0095] In addition, based on the above reaction method, different conditions shown in Table 2 were used to chemically catalyze 3-hydroxypropionic acid to prepare malonic acid. The reaction condition settings and the results of 3-hydroxypropionic acid conversion rate and malonic acid selectivity are shown in Table 2.
[0096] Table 2. Changes in malonic acid yield under different reaction conditions
[0097]
[0098] It can be seen from the data in Table 2 that 3-hydroxypropionic acid can be converted into malonic acid under the catalysis of the above catalyst at a low temperature of 50 to 100°C. The catalytic effects of different catalysts are also different. When the active components of the catalyst are one or more of Pd, Cu, and Au, the 3-hydroxypropionic acid conversion rate and malonic acid selectivity are high. In particular, the catalyst with Au and Cu co-loaded on the oxide carrier has a better catalytic effect. In addition, the inventors found that compared with the catalyst with Au or Cu loaded on the oxide carrier alone (2.5% Cu / TiO 2 and 2.5% Au / TiO 2 ), 2%Au0.5%Cu / TiO with equal weight of Au and Cu 2 The catalytic effect of the catalyst is better, and it is obvious that there is a synergistic effect between the co-loaded Au and Cu metals (comparison groups 6, 7, and 10).
[0099] Generally speaking, catalytic reactions require higher temperatures to be effective. The present invention can achieve catalytic oxidation of 3-hydroxypropionic acid to malonic acid at a lower temperature of 50 to 100°C. Within this range, a lower temperature (50°C) will reduce the conversion rate of 3-hydroxypropionic acid and the selectivity of malonic acid, while a higher reaction temperature (100°C) will not increase the conversion rate of 3-hydroxypropionic acid and the selectivity of malonic acid (comparison groups 10, 15, and 16).
[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for preparing malonic acid, the preparation method comprising: 3-Hydroxypropionic acid undergoes oxidation reaction at 50-100°C in an oxygen-containing atmosphere and a chemical catalyst to obtain malonic acid; The reaction route is: Wherein, the chemical catalyst is a supported catalyst with an active metal component supported on an oxide support; The oxide carrier is one or more selected from TiO2, CeO2, ZrO2, Fe2O3, SiO2, and the active metal component is one or more selected from Pd, Pt, Cu, and Au.
2. The preparation method according to claim 1, characterized in that: The oxygen content in the oxygen-containing atmosphere is 5-80%, preferably, the oxygen-containing atmosphere is air; and / or In the chemical catalyst, the active metal component supported by the oxide carrier is one or more selected from Pd, Cu, Au, preferably Au and Cu; and / or In the chemical catalyst, the loading amount of the active metal component is 0.2-5wt%, preferably 0.5-3wt%, of the oxide carrier.
3. The preparation method according to claim 1 or 2, characterized in that: The chemical catalyst is one or more selected from the following catalysts: Au / TiO2, Au / CeO2, Au / Fe2O3 catalysts with Au loading of 0.5wt%, 1wt%, 2wt% or 2.5wt% respectively; Pd / CeO2, Pd / ZrO2 catalysts with Pd loading of 0.5wt%, 1wt% or 2wt% respectively; Pt / TiO2, Pt / SiO2 catalysts with Pt loading of 0.5wt% or 1wt% respectively; Cu Cu / TiO2, Cu / CeO2, Cu / Fe2O3 catalysts with loading amounts of 0.2wt%, 0.3wt%, 0.5wt% or 2.5wt% respectively; PdCu / TiO2 catalyst with a Pd loading amount of 1wt% and a Cu loading amount of 1wt%; PtCu / TiO2 catalyst with a Pt loading amount of 1wt% and a Cu loading amount of 1wt%; AuCu / TiO2 catalyst with a Au loading amount of 2wt% and a Cu loading amount of 0.5wt%; In particular, the chemical catalyst is an AuCu / TiO2 catalyst with an Au loading of 2 wt% and a Cu loading of 0.5 wt%; The above percentages are the mass percentages of the corresponding metals in the catalyst to the carrier.
4. The preparation method according to any one of claims 1 to 3, characterized in that The chemical catalyst is prepared by an impregnation method, and the preparation method is selected from one of the following methods: Method 1: A method for preparing a catalyst in which an oxide carrier alone supports Cu, comprising the following steps: impregnating the oxide carrier in an aqueous solution of copper nitrate, and then drying to obtain a catalyst precursor; calcining the catalyst precursor at 350-500° C. in an oxidizing atmosphere to obtain the chemical catalyst; Method 2: A method for preparing a catalyst of Pd, Pt or Au supported on an oxide carrier, comprising the following steps: impregnating the oxide carrier in an aqueous solution of a soluble acid or salt of the active metal, and then drying to obtain a catalyst precursor; reducing the catalyst precursor at 200-380° C. in a reducing atmosphere to obtain the chemical catalyst; Method 3: A method for preparing a catalyst containing multiple catalysts such as Pd, Pt, Au or Cu loaded on an oxide carrier: the oxide carrier is impregnated in an aqueous solution of a soluble acid or salt of the active metal, and then dried to obtain a catalyst precursor; the catalyst precursor is calcined in N2 at 300-500°C, and then reduced in a reducing atmosphere at 250-350°C to obtain the chemical catalyst.
5. The preparation method according to claim 4, characterized in that: In method 2 or 3, the soluble acid or salt of the active metal is one or more selected from H2PdCl6, H2PtCl6, Cu(NO3)2 and HAuCl4, and hydrates thereof; the concentration of the active metal in the aqueous solution of the soluble acid or salt of the active metal is 20-50wt%, preferably 25-40wt%; and / or In methods 1 to 3, the impregnation is carried out under stirring for 5-15 hours, preferably 7-10 hours; and / or In methods 1 to 3, the drying step is: first evaporate the solvent, then dry at 90-120°C for 5-15h: and / or In method 2, the reducing atmosphere is an H2 / N2 atmosphere, in particular an atmosphere in which the hydrogen content is 10-30%, preferably an atmosphere in which the hydrogen content is 20%; and / or In method 2, the reduction is carried out at 250-350° C.; the reduction time is 1-6 h, more preferably 2-4 h.
6. The preparation method according to claim 1, characterized in that: The mass ratio of the active metal component of the chemical catalyst to 3-hydroxypropionic acid is 0.00001-0.001:1, preferably 0.00005-0.0005:1; and / or The temperature of the chemical catalytic reaction is 60-90°C; the reaction time is 1-6 hours; and / or The chemical catalytic reaction is carried out in the presence of a base, which is one or more selected from NaOH, KOH, and Ca(OH)2, preferably Ca(OH)2; in the reaction system, the concentration of the base is 0.003 to 0.015 mol / L, preferably 0.007 to 0.008 mol / L.
7. The preparation method according to claim 1, characterized in that: The 3-hydroxypropionic acid is prepared by a biocatalytic method, which comprises: In a polar solvent, glycerol undergoes a continuous dehydration-oxidation reaction under the action of air atmosphere and enzyme catalyst to obtain 3-hydroxypropionic acid; The reaction route is as follows: Wherein, the enzyme catalyst includes dehydratase, coenzyme NAD + and aldehyde dehydrogenase.
8. The preparation method according to claim 7, characterized in that: The dehydratase is selected from glycerol dehydratase, arabinose dehydratase, gluconate dehydratase and a mixed enzyme of two or more of the above enzymes, preferably glycerol dehydratase; and / or The polar solvent is water, methanol, ethanol or a combination thereof, preferably water.
9. The preparation method according to claim 7, characterized in that: In the continuous dehydration-oxidation reaction, the glycerol concentration is 100-200 g / L, preferably 150 g / L; and / or The mass ratio of glycerol to dehydratase is 5:(1-10), preferably 5:(1-8); and / or Glycerol and aldehyde dehydrogenase, coenzyme NAD + The mass ratio is 5:(1-10):(1-5), preferably 5:(1-6):(1-4); and / or The pressure of the continuous dehydration-oxidation reaction is 15-35 atm; and / or The temperature of the continuous dehydration-oxidation reaction is 20-40°C, preferably 30-37°C; and / or In some embodiments, the continuous dehydration-oxidation reaction time is 5-25 hours, preferably 8-16 hours.
10. The preparation method according to claim 7, characterized in that: The biocatalytic method of 3-hydroxypropionic acid further comprises separation and purification, wherein the separation and purification step comprises: using ion exchange resin as an adsorbent to enrich and separate 3-hydroxypropionic acid in the reaction solution to obtain a 3-hydroxypropionic acid enriched solution; The ion exchange resin is a weakly basic anion exchange resin, and its eluent is a 0.03 mol / L NaOH aqueous solution; Furthermore, 4-10 wt%, w / v activated carbon powder is added to the 3-hydroxypropionic acid enriched solution for decolorization.