CN103145545B - A kind of method preparing hydroxymalonic acid for glycerol catalysis oxidation - Google Patents

Abstract

A method for preparing glycerol by catalytic oxidation of glycerol, using a noble metal-supported catalyst, under mild conditions (temperature 20-80°C, pressure 0.3-3.0MPa) to efficiently catalyze and oxidize glycerol to directly generate propanol Diacid. The conversion rate of glycerol reaches over 99%, and the catalyst selectivity reaches 95%. The method is highly efficient and environmentally friendly, and has great application prospects.

Description

A method for preparing tartronic acid by catalytic oxidation of glycerol

technical field

The invention relates to the field of chemistry and chemical engineering, in particular to a method for preparing tartronic acid by catalytic oxidation of glycerol and an application thereof.

Background technique

The energy crisis and the aggravation of environmental problems have prompted the urgent need for people to find renewable alternative fuels. As a clean, high cetane number, high heat of combustion, and free of sulfur and aromatics, biodiesel is an environmentally friendly green alternative fuel. Its production technology has been widely promoted and developed in recent years (WO2008151149-A2, US2007048848-A1, CN200710098486.7). With the gradual warming of the biodiesel industry, the development and utilization of downstream products of its 10% co-product—biomass-based glycerol (every ten tons of biodiesel will produce one ton of crude glycerin) has aroused global widespread Because these co-products cannot be used and disposed of in time, it may cause waste of resources and become a new source of pollution. Researchers around the world are committed to developing and researching new high-value-added chemicals of glycerol, and have achieved certain results. Achievements, such as the development and application of the conversion of glycerol to glycerol di-tert-butyl ether and glycerol tri-tert-butyl ether as fuel additives, the development and application of glycerol to 1,2-propanediol technology, etc. Therefore, the effective development and utilization of glycerol is an important measure to reduce the cost of biodiesel, improve resource utilization, efficiently and economically utilize biomass energy, and improve the cycle benefit of biomass energy.

Tartronic acid is a kind of green chemical with broad application prospects. It can be used as the starting material of polyglycolic acid to produce a new generation of biodegradable plastics. It can also be used in chelating agents, cleaning agents, pharmaceutical preparations, neutralization agents, etc. (JP8151345-A, WO2006058695-A1). At present, the traditional preparation method of tartronic acid is to use diethyl malonate as raw material to produce through multi-step organic synthesis reaction, and diethyl malonate comes from petroleum route. There are many steps in this synthetic production method, and the raw material cost High, complex products, difficult separation and purification and other disadvantages. Therefore, the catalytic oxidation of glycerol as a raw material to prepare tartronic acid not only has broad application prospects, but also is an efficient, high-quality, and environmentally friendly green approach.

The difficulty of selective oxidation of glycerol to prepare tartronic acid is closely related to the special structure of glycerol molecule. The key scientific problem in developing the preparation of tartronic acid from glycerol molecules is how to selectively oxidize the two terminal hydroxyl groups of glycerol while retaining its secondary hydroxyl groups. Selective oxidation is extremely challenging due to the similar chemical properties of the three hydroxyl groups of the glycerol molecule. So far, there are very few reports on the preparation of tartronic acid from glycerol. Some reports report the preparation of propanol acid from glycerol and produce tartronic acid at the same time, but the latter all exist in the form of by-products. Studies have shown that the catalysts for the preparation of tartronic acid by catalytic oxidation are mainly multi-metal supported catalysts prepared with Au as the main active component and Pd, Pt, etc. Hutchings et al. used 0.5% Au-0.5% Pd/C to catalyze oxygen glycerol, reacted at 60°C for 4 hours, the conversion rate reached 100%, and the selectivity of tartronic acid reached 40%; when using single metal support, the Au/C The selectivity reached only 29%, and the conversion was 100%. (Silvio Carrettin, Paul McMorn, Peter Johnston and G.J. Hutchings, Phys. Chem. Chem. Phys., 2009, 11, 4952 4961). Recently, Sakurai et al. used PVP-wrapped Au-Pd colloids as a quasi-homogeneous catalyst, reacted at 80°C for 24h, the conversion rate reached 100%, and the selectivity of tartronic acid reached 45% (Salprima Yudha S, Raghu Nath Dhital, Hidehiro Sakurai, Tetrahedron Lett., 2011, 52, 2633-2637). So far, studies have found that only multi-metal supported catalysts such as Au, Pt, and Pd have good catalytic effects, and single-metal catalysts are not active. Due to the weak force between the noble metal and the carbon support, the noble metal particles are easy to grow and the activity decreases as the oxidation reaction proceeds or is used repeatedly.

The supported catalyst provided by the invention enables the carrier to selectively adsorb glycerol molecules by adjusting the interaction between the carrier and the metal component, and at the same time cooperates with the oxidation of the metal component to develop a route for preparing tartronic acid from glycerol. The method provided by the invention not only has higher catalytic activity and selectivity, but also has stronger stability and stronger popularization and application value.

Contents of the invention

The object of the present invention is to develop a green route to efficiently and environmentally friendly produce tartronic acid using biomass-based glycerol as a raw material, that is, under the action of a catalyst, use pure water as a solvent to catalyze the oxidation of glycerol at low temperature and low pressure Synthesis of tartronic acid.

According to the content of the present invention, in order to improve the reaction efficiency and reduce the formation of reaction by-products, the composition and dosage of the active components of the catalyst need to be properly screened. In order to ensure the selectivity of the catalyst, the active components designed in the present invention are based on noble metals such as Au, Pt, and Pd as the main active components, and Bi, Ni, Ce, etc. ratios to prepare supported catalysts. On the other hand, in order to improve the activity of the catalyst and reduce the cost of the catalyst, the loading of the active component is controlled between 0.5%-15%, wherein the ideal loading of the main active component is 2%, and the ideal total loading is 5% %.

According to the content of the present invention, in order to improve the reaction efficiency and reduce the generation of by-products, it is necessary to select a carrier with stable chemical properties, which can form a strong interaction with the active components, has a large specific surface area and does not affect its catalytic performance. The surface of the support with acid centers can have a strong interaction with the active metal precursor, so that the active components are evenly dispersed to form a catalyst precursor. Therefore, in addition to acidic supports such as CeO ₂ , Al ₂ O ₃ , and hydrotalcite, catalysts prepared using some molecular sieves (NaY, NaX, HY, Hβ, HX, ZSM-5, mordenite, etc.) Inexpensive, with excellent performance and high stability.

According to the content of the present invention, in order to disperse the active components of the catalyst uniformly on the carrier, improve the stability of the active components on the carrier, and prevent the sintering and agglomeration of metal particles. The catalyst is prepared by impregnation method, sol-gel method, co-precipitation method and hydrothermal method, so that active components such as Au, Pd, Pt form uniformly dispersed nanoparticles on the carrier, and other metal groups such as Bi, Ni, Ce, etc. are added Particles can not only form alloys with active components, but also stabilize nano-metal particles such as Au, Pd, and Pt to avoid their sintering and agglomeration. Therefore, in the design of active components of catalysts, in addition to using active components Au, Pd, and Pt, other metals must be relied on to stabilize the presence of the active components on the support, such as Bi, Ni, Ce, etc.

According to the present invention, in order to stably disperse the active components on the surface of the carrier, the preparation of the catalyst needs to be carried out at low temperature to avoid agglomeration and growth of metal particles at high temperature. In order to achieve rapid reduction of metal salt precursors to generate nanoscale particles, the present invention uses chemical reduction technology to reduce metal components to metal or metal alloy. A typical synthesis method is as follows:

Typical synthesis method 1: Under the control of the water bath temperature of 50°C, two different metal salts HPtCl ₄ and HAuCl ₄ are prepared into a solution according to a certain ratio, and the calculated amount of carrier NaY is added to the stirred solution, and stirred at constant temperature for 2 hours. Use the constant pressure titration method to slowly add the calculated amount of reducing agent sodium citrate dropwise to the mixed solution of the stirred metal salt and the carrier. After the dropwise addition, continue to stir for 4 hours, drop to room temperature, wash and centrifuge with pure water for 3 -5 times to get the catalyst, dry the catalyst.

Typical synthesis method 2: Controlling the temperature of the water bath at 60°C, prepare a solution containing HPtCl ₄ , HAuCl ₄ and Ce(NO ₃ ) ₃ , and add the reducing agent sodium citrate dropwise to the stirred metal salt solution by constant pressure titration, After the dropwise addition, continue to stir for 2 hours. When the solution appears transparent purple red, add the calculated amount of carrier ZSM-5, and stir at constant temperature for 2 hours. Cool down to room temperature, wash and centrifuge with pure water for 3-5 times to obtain a catalyst, and dry the catalyst in a hydrogen atmosphere at 100°C.

Typical synthesis method 3: Controlling the temperature of the water bath at 50°C, prepare a solution containing HAuCl ₄ and Bi(NO ₃ ) ₃ , add the calculated amount of carrier CeO ₂ to the stirred metal salt solution, and stir at constant temperature for 2 hours. Use the constant pressure titration method to drop the calculated amount of reducing agent sodium borohydride into the mixed solution of the stirred metal salt and the carrier. After the dropwise addition, continue to stir for 4 hours, drop to room temperature, wash and centrifuge with pure water for 3- 5 times, and finally dried to obtain the catalyst.

Typical synthesis method 4: Control the temperature of the water bath at 60°C, mix the carrier HY and the metal salt solution HAuCl ₄ under stirring, stir at constant temperature for 6 hours, add sodium citrate reducing agent, continue stirring for 2 hours, cool down to room temperature, and use deionized water After washing 3-5 times and centrifuging, the catalyst was dried at 100°C under a hydrogen atmosphere.

According to the content of the present invention, in order to improve the reaction efficiency and reduce the reaction cost, this reaction realizes the method of generating tartronic acid through efficient catalytic oxidation under low temperature and low pressure conditions, and avoids the disadvantages of high cost of multi-step synthesis and difficult product separation. The catalyst for this reaction is carried out for 4-10 hours under mild conditions of 20-80° C. and 0.3-3.0 MPa, which can efficiently catalyze the oxidation of glycerol into tartronic acid, and realize green and energy-saving catalysis.

According to the present invention, in order to speed up the reaction rate and stabilize the product with strong acidity, an appropriate amount of alkali needs to be added in the reaction to activate the reaction substrate and stabilize the acidic product generated, so as to promote the reaction to proceed further to the right. In the present invention, a small amount of alkali is added into the reaction solution, and the object is realized by adjusting the molar ratio of the substrate to the added alkali to be 1-20. The type of alkali added can be LiOH, KOH, NaOH, Ca(OH) ₂ , CH ₃ ONa, CH ₃ OK and the like.

The conversion rate of glycerol in the invention reaches more than 99 percent, and the selectivity of the catalyst reaches 95 percent. The method is highly efficient and environmentally friendly, and has great application prospects.

Description of drawings

Figure 1 is the standard sample liquid chromatogram triol standard spectrum

Fig. 2 is the standard sample liquid phase chromatogram of propanol dioic acid standard chromatogram

Figure 3 is the qualitative analysis spectrum of the reaction product control method

detailed description

The following examples will help to understand the present invention, but the content of the present invention is not limited thereto.

Example 1:

The reaction vessel is a high-pressure reactor with 10ml polytetrafluoroethylene lining inside, and 0.23 grams of Glycerol (glycerol), 1.5 grams of NaOH, and 6.92 milliliters of water are added to the reactor, and 0.31 grams of AuBi/CeO ₂ (Au0.5wt% , Bi1.5wt%) as the catalyst, after the temperature program was raised to 30°C, 1.5MPa oxygen was added, and the reaction was carried out for 7 hours. After the reaction product was centrifuged, the supernatant was removed and analyzed by HPLC. The reaction results are shown in Table 1.

Example 2:

The reaction vessel is a high-pressure reactor with 10ml polytetrafluoroethylene lining inside, and 0.23 grams of Glycerol, 1.5 grams of NaOH, and 6.92 milliliters of water are added to the reactor, and 0.33 grams of AuPdBi/Al ₂ O ₃ (Au1wt%, Pd1wt%, Bi1 .5wt%) as the catalyst, after temperature program was raised to 30°C, 1.5MPa oxygen was added, and the reaction was carried out for 7 hours. After the reaction product was centrifuged, the supernatant was removed and analyzed by HPLC. The reaction results are shown in Table 1.

Implement your 3:

The reaction vessel is a high-pressure reactor with a 10ml polytetrafluoroethylene lining inside, and 0.46 grams of Glycerol, 1.6 grams of NaOH, and 14.4 milliliters of water are added to the reactor, and 0.31 grams of AuCe/hydrotalcite (Au2wt%, Ce1wt%) is used as a catalyst, After the temperature was raised to 80° C., 0.3 MPa oxygen was added, and the reaction was carried out for 9 hours. During the reaction, oxygen was continuously supplied to ensure that the reaction was carried out at constant temperature and pressure. After the reaction product was centrifuged, the supernatant was removed and analyzed by HPLC. The reaction results are shown in Table 1.

Example 4:

The reaction vessel is a high-pressure reaction kettle with 10ml polytetrafluoroethylene lining inside. Take 0.46 grams of Glycerol, 0.8 grams of NaOH, and 16 milliliters of water into the reaction kettle. 0.35 grams of Au/HY (Au 2wt%) is used as a catalyst, and the temperature is raised to After 60°C, add 0.3MPa oxygen, and react for 7 hours. During the reaction, oxygen is continuously replenished to ensure that the reaction proceeds at constant temperature and pressure. After the reaction product was centrifuged, the supernatant was removed and analyzed by HPLC. The reaction results are shown in Table 1.

Example 5:

The reaction vessel is a high-pressure reactor with 10ml polytetrafluoroethylene lining inside, and 2.3 grams of Glycerol, 4 grams of NaOH, and 80 milliliters of water are added to the reactor, and 0.35 grams of AuPtCe/NaY (Au1%, Pd1wt%, Ce1wt%) is After the catalyst and the temperature were raised to 50° C., 0.6 MPa oxygen was added, and the reaction was carried out for 9 hours. During the reaction, oxygen was continuously supplied to ensure that the reaction was carried out at constant temperature and pressure. After the reaction product was centrifuged, the supernatant was removed and analyzed by HPLC. The reaction results are shown in Table 1.

Embodiment 6:

The reaction vessel is a high-pressure reaction kettle with 10ml polytetrafluoroethylene lining inside, and 0.69 grams of Glycerol, 0.8 grams of NaOH, and 16 milliliters of water are added to the reaction kettle, and 0.35 grams of PdCe/ZSM-5 (Pd2wt%, Ce1wt%) is used as a catalyst 1. After the temperature was raised to 30° C., 1.0 MPa oxygen was added, and the reaction was carried out for 6 hours. During the reaction, oxygen was continuously supplied to ensure that the reaction was carried out under constant temperature and pressure. After the reaction product was centrifuged, the supernatant was removed and analyzed by HPLC. The reaction results are shown in Table 1.

Embodiment 7:

The reaction vessel is a high-pressure reactor with 10ml polytetrafluoroethylene lining inside, and 0.69 gram of Glycerol, 0.8 gram of NaOH, and 16 milliliters of water are added to the reactor, and 0.35 gram of PtPdBi/ZSM-5 (Pt2wt%, Pd2wt%, Bi1wt% ) as a catalyst, after the temperature was raised to 30°C, 2.5MPa oxygen was added, and the reaction was carried out for 6 hours. After the reaction product was centrifuged, the supernatant was removed and analyzed by HPLC. The reaction results are shown in Table 1.

Embodiment 8:

The reaction vessel is a high-pressure reactor with a 10ml polytetrafluoroethylene liner inside, and 0.23 grams of Glycerol, 0.8 grams of NaOH, and 7.62 mg of water are added to the reactor, 0.35 grams of Pt/Hβ (Pt2wt%) is used as a catalyst, and the temperature is programmed to rise to 80 After ℃, add 0.3MPa oxygen, and react for 9 hours. During the reaction, oxygen is constantly added to ensure that the reaction is carried out under constant temperature and pressure. After the reaction product was centrifuged, the supernatant was removed and analyzed by HPLC. The reaction results are shown in Table 1.

Embodiment 9:

The reaction vessel is a high-pressure reactor with a 10ml polytetrafluoroethylene liner inside, and 1.15 grams of Glycerol, 4.0 grams of NaOH, and 38.1 mg of water are added to the reactor, and 0.40 grams of PdNi/HY (Pd2wt%, Ni 2wt%) is used as a catalyst. After the temperature was raised to 60° C., 0.6 MPa oxygen was added, and the reaction was carried out for 3 hours. During the reaction, oxygen was continuously supplied to ensure that the reaction was carried out at constant temperature and pressure. After the reaction product was centrifuged, the supernatant was removed and analyzed by HPLC. The reaction results are shown in Table 1.

Example 10:

The reaction vessel is a high-pressure reaction kettle with 10ml polytetrafluoroethylene lining inside, and 0.69 grams of Glycerol, 1.6 grams of NaOH, and 6.82 mg of water are added to the reaction kettle, and 0.33 grams of Pt Ni/HY (Pt2wt%, Ni 1wt%) is used as a catalyst 1. After the temperature was raised to 60° C., 0.6 MPa oxygen was added, and the reaction was carried out for 3 hours. During the reaction, oxygen was continuously supplied to ensure that the reaction was carried out under constant temperature and pressure. After the reaction product was centrifuged, the supernatant was removed and analyzed by HPLC. The reaction results are shown in Table 1.

Example 11:

The reaction vessel is a high-pressure reaction kettle with 10ml polytetrafluoroethylene lining inside, and 0.69 grams of Glycerol, 0.8 grams of NaOH, and 7.6 milliliters of water are added to the reaction kettle, and 0.42 grams of AuPt Ni/hydrotalcite (Au 1wt%, Pt 1wt%, Ni 1wt%) was used as the catalyst. After the temperature was programmed to 60° C., 0.3 MPa oxygen was added to react for 6 hours. During the reaction, oxygen was continuously supplemented to ensure that the reaction was carried out at constant temperature and pressure. After the reaction product was centrifuged, the supernatant was removed and analyzed by HPLC. The reaction results are shown in Table 1.

Example 12:

The reaction vessel is a high-pressure reactor with 10ml polytetrafluoroethylene lining inside, and 0.46 grams of Glycerol, 0.8 grams of NaOH, and 16 milliliters of water are added to the reactor, and 0.37 grams of PtCeNi/ZSM-5 (Pt 2wt%, Ce1wt%, Ni1wt% %) as the catalyst, after the temperature was raised to 80° C., 0.3 MPa oxygen was added, and the reaction was carried out for 9 hours. During the reaction, oxygen was continuously supplemented to ensure that the reaction was carried out at constant temperature and pressure. After the reaction product was centrifuged, the supernatant was removed and analyzed by HPLC. The reaction results are shown in Table 1.

Example 13:

The reaction vessel is a high-pressure reactor with a 10ml polytetrafluoroethylene lining inside, and 0.92 grams of Glycerol, 4 grams of NaOH, and 29.7 milliliters of water are added to the reactor, and 0.56 grams of AuBiNi/Al ₂ O ₃ (Au 2wt%, Bi1wt%, Ni1wt%) was used as the catalyst, and after the temperature was programmed to 70°C, 0.6MPa oxygen was added to react for 6 hours. During the reaction, oxygen was constantly supplemented to ensure that the reaction was carried out at constant temperature and pressure. After the reaction product was centrifuged, the supernatant was removed and analyzed by HPLC. The reaction results are shown in Table 1.

Example 14:

The reaction vessel is an autoclaved autoclave with 10ml polytetrafluoroethylene lining inside, and 1.15 grams of Glycerol, 2 grams of NaOH, and 36.1 milliliters of water are added to the reactor, and 0.40 grams of AuPdPt/NaY (Au1wt%, Pd1wt%, Pt1wt%) is After the catalyst and the temperature were raised to 50° C., 0.3 MPa oxygen was added, and the reaction was carried out for 6 hours. During the reaction, oxygen was continuously replenished to ensure that the reaction was carried out at constant temperature and pressure. After the reaction product was centrifuged, the supernatant was removed and analyzed by HPLC. The reaction results are shown in Table 1.

Table 1. Catalytic oxidation of glycerol to produce tartronic acid reaction results

Analytical method for glycerol oxidation mixed products

1. Decomposition instruments and analysis conditions

1 Analytical instrument

Waters e2695 high performance liquid chromatography

Waters 2414 Differential Refractive Index Detector

2 Analytical reagents and medicines

Glycerol: analytically pure (98%), Tianjin Kemiou Chemical Reagent Company;

Diglyceric acid: analytically pure (98%);

Adipic acid internal standard (analytical pure): Tianjin Kemiou Chemical Reagent Development Center;

2. Qualitative analysis of oxidation products

1. Qualitative analysis of known standard samples

Take 0.002 g of the known standard sample diglyceride, place it in three 10ml volumetric flasks, add the internal standard adipic acid, dilute to the mark with deionized water, and mix well. Samples were injected under the above-mentioned chromatographic analysis conditions to obtain 3 corresponding chromatograms. Under given chromatographic conditions, the retention time of each substance obtained is as follows:

Diglyceric acid (product): 8.06min.;

Glycerol (reactant): 12.51min.;

Internal standard: 14.33min..

Standard sample liquid chromatogram

The standard spectrum of glycerol is shown in Figure 1

species keep time Peak area Peak height 1 Glycerol 12.514 914919 45535 2 Adipic acid 14.307 1041316 40945

The standard spectrum of tartronic acid is shown in Figure 2

species keep time Peak area Peak height 1 Protonate 8.068 415660 25764 2 Adipic acid 14.326 1052677 40970

2. Qualitative analysis of reaction products by contrast method as shown in Figure 3

species keep time Peak area Peak height 1 Protonate 8.082 987547 64130 2 Adipic acid 14.297 476584 20236

Claims (7)

1. glycerol is catalyzed the method that hydroxymalonic acid is prepared in oxidation by one kind, it is characterised in that: with pure water as solvent, use your gold Belong to loaded catalyst direct one-step method and glycerol efficiently catalyzing and oxidizing is synthesized hydroxymalonic acid；

Described catalyst main active component is Au or Pt, and the total load amount of catalyst activity component is 5%, and uses Y molecule Sieve.

The most in accordance with the method for claim 1, it is characterised in that: catalyst uses infusion process, colloid method, coprecipitation or water Full-boiled process is prepared from, and active component needs to use chemical reduction method to make it be supported on carrier, and what chemical reduction procedure used goes back Former dose includes trisodium citrate, ascorbic acid, sodium borohydride or hydrogen.

The most in accordance with the method for claim 2, it is characterised in that: catalyst uses colloid method or infusion process to prepare, and uses lemon The catalyst of lemon acid sodium reduction.

The most in accordance with the method for claim 1, it is characterised in that:

Catalytic reaction certain pressure and at a temperature of carry out, pressure is 0.3～3.0MPa, and temperature is 20～80 DEG C, and oxygen source is oxygen Gas, air or hydrogen peroxide.

5. according to the method described in claim 1 or 4, it is characterised in that: course of reaction needs add a certain amount of alkali and promotes The carrying out of reaction, the amount of the alkali of addition and reaction substrate glycerol mol ratio are 1～20, the kind of alkali have LiOH, KOH, NaOH, Ca(OH)₂、CH₃ONa or CH₃OK。

6. according to the method described in claim 1 or 4, it is characterised in that: catalyst is 0.3Mpa in reaction pressure, and temperature is 60 DEG C, and with oxygen as oxygen source.

The most in accordance with the method for claim 1, it is characterised in that: concentration 20-100mg/g of glycerol.