Catalyst for preparing 1, 3-propylene glycol through glycerol hydrogenation as well as preparation method and application of catalyst
By using a catalyst composed of Pt, W, additives and carriers, the problem of the catalytic system in the prior art decreases the selectivity of 1,3-propylene glycol when increasing the glycerol conversion rate is achieved, and an efficient glycerol hydrogenolysis reaction is achieved. The formation of 1,2-propylene glycol was inhibited.
Patent Information
- Application Number
- CN202311018826.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-14
- Publication Date
- 2025-02-21
AI Technical Summary
While the existing catalytic system improves the glycerol conversion rate, it is difficult to maintain the selectivity of 1,3-propylene glycol without reducing, and inhibit the formation of 1,2-propylene glycol.
A catalyst composed of Pt, W, additives and carriers is a mixture of ZrO2, TiO2, and Al2O3, and the additive is titanate. The transfer of hydrogen atoms from Pt to W is promoted through the additives, thereby improving the catalytic activity of the catalyst. More B acid acidic sites are formed by low temperature reduction, which promotes the formation of 1,3-propylene glycol.
While increasing the glycerol conversion rate, the selectivity of 1,3-propylene glycol is maintained without reducing, and the formation of 1,2-propylene glycol is effectively inhibited, achieving efficient glycerol hydrogenolysis reaction.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of glycerol hydrogenolysis reaction, in particular to a catalyst for preparing 1,3-propylene glycol by hydrogenating glycerol, and a preparation method and application thereof. Background Art
[0002] Glycerol, also known as propylene glycol, is a byproduct of biodiesel production and is widely used in food, medicine, cosmetics, coatings, textiles and papermaking. The main application areas of glycerol in China are the production of propylene oxide, medicines and cosmetics. However, the above applications have not achieved the optimal utilization of oxygen-containing functional groups in glycerol molecules. Deep development of glycerol as a raw material, especially the production of high-value-added chemicals such as propylene glycol through hydrogenation technology, is of great significance for the high-value utilization of glycerol molecules. Among them, 1,3-propylene glycol is the product with the highest added value. It can be used as a solvent, antifreeze agent, emulsifier, plasticizer, detergent, preservative and lubricant. It has important applications in medicine, food, cosmetics and organic synthesis, and is an important chemical raw material. However, the selective generation of 1,3-propylene glycol faces great scientific challenges. Most catalytic systems have a "seesaw" problem of mutual restriction between conversion rate and selectivity. While increasing the conversion rate of glycerol, the selectivity of 1,3-propylene glycol will inevitably decrease. Therefore, the development of an efficient catalyst for hydrogenolysis of glycerol to prepare 1,3-propylene glycol is still a problem that needs to be solved urgently in the chemical industry. Summary of the invention
[0003] In order to overcome the defects of the prior art, the purpose of the present invention is to provide a catalyst and a preparation method thereof, wherein the catalyst can be used for preparing 1,3-propylene glycol by hydrogenating glycerol, and the catalyst can improve the glycerol conversion rate while maintaining the selectivity of 1,3-propylene glycol in the hydrogenation product without decreasing, while inhibiting the formation of 1,2-propylene glycol.
[0004] The present invention provides a catalyst, which comprises Pt, W, an additive and a carrier. The carrier is a mixture of ZrO2, TiO2 and Al2O3; the content of ZrO2 accounts for 70-98% of the carrier mass, the content of TiO2 accounts for 1-10% of the carrier mass, and the content of Al2O3 accounts for 1-20% of the carrier mass;
[0005] Among them, the Pt loading is 0.5-5% of the catalyst mass, the W content is 3-15% of the catalyst mass, and the auxiliary agent content is 0.5-5% of the catalyst mass; preferably, the Pt content is 1-2% of the catalyst mass, the W content is 4-10% of the catalyst mass, and the auxiliary agent content is 1-3% of the catalyst mass.
[0006] In the present invention, the carrier is a mixture of ZrO2, TiO2 and Al2O3, wherein the loading amount of ZrO2 is 70% of the carrier mass, the loading amount of TiO2 is 10% of the carrier mass, and the loading amount of Al2O3 is 20% of the carrier mass. The present invention utilizes the abundant hydroxyl groups on the surface of the carrier to promote the loading of active components on the carrier, thereby improving the catalytic effect of the catalyst.
[0007] In the present invention, the auxiliary agent is one or more of zirconium titanate, sodium titanate, magnesium titanate, lithium titanate, calcium titanate, etc.; preferably, it is sodium titanate, calcium titanate or a mixture thereof.
[0008] The reactants of the glycerol hydrogenolysis reaction are hydrogen and glycerol. Pt can activate hydrogen, but cannot activate glycerol. By adopting the above technical solution, the hydrogen adsorbed on Pt is transferred to the vicinity of the W atom under the reaction conditions through the promotion of the auxiliary agent to react with the hydroxyl group of glycerol. The auxiliary agent is used to promote the transfer process of hydrogen atoms from Pt to W, thereby improving the catalytic activity of the catalyst. In addition, the addition of the auxiliary agent is conducive to the low-temperature reduction of the W surface under the reaction conditions to form more B acid sites, promote the formation of 1,3-propylene glycol, and thus improve the selectivity of 1,3-propylene glycol. This reaction follows the common carbon cation isomerization hydrogenation mechanism. The secondary hydroxyl group of the glycerol molecule reacts with WO x The B acid center is coordinated and protonated, and then the hydroxyl group on the secondary carbon is removed to form a carbon cation, which is adsorbed again on the surface of the carrier through the primary hydroxyl group and rapidly hydrogenated to generate 1,3-propylene glycol. Therefore, the catalyst prepared by the present invention undergoes a rapid hydrogen transfer process and subsequent isomerization under the action of the auxiliary agent, which is beneficial to improving the glycerol conversion rate and the selectivity of 1,3-propylene glycol.
[0009] In the present invention, the addition of the additive promotes the transfer of hydrogen species on the Pt surface to W using the additive as a bridge, thereby promoting the catalytic activity of the catalyst; on the other hand, the additive particles are beneficial to the dispersion and reconstruction of W on the carrier surface, which is beneficial to increase the surface B acid content, thereby improving the selectivity of 1,3-propylene glycol. The titanate used in the present invention does not need to be dissolved in a specific solvent, and can be directly added to the preparation system through conventional water or alcohol dispersion, and the carrier is modified through solid phase heating reaction, which significantly reduces the catalyst preparation process and the discharge of three wastes.
[0010] Furthermore, in the catalyst of the present invention, a small amount of other types of oxides such as SiO2, CeO2, V, Cr, Mn, Mo, Fe, Ni, Cu, Au, etc. can be allowed to exist without changing the performance.
[0011] The present invention also provides a method for preparing a catalyst, which specifically comprises the following steps:
[0012] Step 1: Weigh zirconium oxychloride, tetrabutyl titanate and aluminum chloride according to the ratio, dissolve them in ethanol, and stir at 60-90° C. for 30-90 minutes to obtain a carrier solution.
[0013] The mass ratio of the zirconium oxychloride, tetrabutyl titanate and aluminum chloride is 70-98%:1-10%:1-20% calculated based on the mass ratio of zirconium oxide, titanium oxide and aluminum oxide; preferably, it is 7:1:2.
[0014] Step 2: Weigh the W precursor according to the loading amount and dissolve it in ethanol, then transfer the W-containing ethanol solution to the carrier solution prepared in step 1, and stir at 60-90°C for 30-90 minutes to obtain WO x / Carrier solution.
[0015] The loading amount is calculated as WO3 and is 3-15% of the catalyst mass; preferably, 5-10%.
[0016] Step 3: weigh the titanate additive according to the loading amount and disperse it in ethanol, and then transfer the titanate ethanol dispersion to the WO prepared in step 2. x / carrier solution, continuously stirred at 60-90°C until uniformly dispersed, then dried, and calcined at 500-750°C in air atmosphere to obtain titanate-WO x / vector.
[0017] The loading amount of the auxiliary agent is 0.5-5% of the mass of the catalyst; preferably, 1-3%.
[0018] Step 4: Weigh the titanate-WO prepared in step 3 x / The carrier is spread flat on a surface dish, and then a chloroplatinic acid aqueous solution is added dropwise to the surface dish according to the loading amount to immerse the titanate-WO x / carrier, stand at room temperature for 5 to 10 hours, then dry, and calcine at 400 to 600 ° C in air atmosphere to obtain Pt-titanate-WO x / carrier composite catalyst.
[0019] The Pt loading is 0.5-5% of the catalyst mass; preferably, 1-2%.
[0020] By adopting the above technical scheme, the obtained new Pt-based catalyst exhibits efficient hydrogen dissociation ability and multi-site overflow transfer ability of adsorbed hydrogen, improves the low-valent W species and its B acid sites under low-temperature reaction conditions, is beneficial to the formation of 1,3-propylene glycol, and thus can improve the selectivity of 1,3-propylene glycol.
[0021] The present invention adopts an impregnation method to prepare the catalyst, and the preparation process is simple and easy to control.
[0022] In the present invention, in step 2, the precursor of W is one or more of phosphotungstic acid, sodium tungstate, sodium phosphotungstate, silicotungstic acid, ammonium phosphotungstate, etc.; preferably, it is phosphotungstic acid.
[0023] By adopting the above technical solution, phosphotungstic acid is dissolved in ethanol, and a W-containing catalyst is prepared by a co-mixing method, which is conducive to uniform dispersion of W.
[0024] The present invention also provides a catalyst prepared by the method.
[0025] The present invention also provides the use of the catalyst in the reaction of preparing 1,3-propylene glycol by hydrogenation of glycerol. The specific reaction conditions are: reaction pressure of 3-5 MPa, reaction temperature of 130-160° C., and reaction raw material of 10-70 wt% glycerol aqueous solution. The reaction is carried out in a fixed bed reactor. In the application, the catalyst can improve the glycerol conversion rate while maintaining the selectivity of 1,3-propylene glycol in the hydrogenation product without decreasing, and inhibiting the formation of 1,2-propylene glycol.
[0026] The present invention achieves the coordination of adsorption and diffusion of glycerol on the catalyst surface and in the pores at medium concentration by adopting the above technical scheme, promotes the adsorption of glycerol molecules, and accelerates the desorption of 1,3-propylene glycol products.
[0027] The beneficial technical effects of the present invention include: the glycerol hydrogenolysis reaction is a tandem process, Pt can activate hydrogen to obtain hydrogen atoms adsorbed on the Pt surface to achieve adsorption equilibrium; the latter is usually transferred to the oxide of W to form protons through "hydrogen overflow", and the protons react with the hydroxyl groups of glycerol to undergo a dehydration reaction. The titanate additive provided by the present invention can significantly improve the efficiency of "hydrogen overflow", pull the equilibrium of Pt activated hydrogen to the right, thereby improving the catalytic activity of the catalyst; in addition, the titanate species enhances the strength and quantity of the proton acid combined with W, and improves the selectivity of 1,3-propylene glycol. The titanate used in the present invention is a commercial chemical, and the raw materials are abundant and easy to obtain. During the preparation process, it is simply blended with other components, and there is no need to add other complex inorganic acids and bases or organic reagents to undergo complex chemical reactions to dissolve them, which is convenient for mass production and preparation of the target catalyst, and the preparation process is simple and easy to control; it has the advantage of industrial scale-up. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 The X-ray diffraction patterns of the catalysts obtained in Examples 1 to 7 of the present invention and Comparative Examples 1 to 2 are shown.
[0029] Figure 2 This is a graph showing the pyridine adsorption results of the catalyst obtained in Example 2 of the present invention.
[0030] Figure 3This is a transmission electron microscope image of the catalyst obtained in Example 3 of the present invention. DETAILED DESCRIPTION
[0031] The present invention is further described in detail below in conjunction with the examples. The process, conditions, experimental methods, etc. for implementing the present invention, except for the contents specifically mentioned below, are all common knowledge and common common sense in the art, and the present invention has no particular limitations.
[0032] Example 1
[0033] A catalyst for preparing 1,3-propylene glycol by hydrogenating glycerol, the catalyst comprising Pt, W, an auxiliary agent and a carrier, wherein the loading amount of Pt is 2% of the catalyst mass, the loading amount of W is 10% of the carrier mass, the loading amount of the auxiliary agent is 1% of the carrier mass, the auxiliary agent is Na2TiO3, and the carrier is a mixture of ZrO2, TiO2 and Al2O3, wherein the W ZrO2 :w TiO2 :w Al2O3 =7:1:2.
[0034] The preparation method of the catalyst specifically comprises the following steps:
[0035] Step 1: Weigh zirconium oxychloride, tetrabutyl titanate and aluminum chloride according to the ratio, dissolve them in ethanol, and stir at 60° C. for 90 minutes to obtain a carrier solution.
[0036] Step 2: Weigh the W precursor according to the loading amount and dissolve it in ethanol. Then transfer the W-containing ethanol solution to the carrier solution prepared in step 1 and stir at 60°C for 90 min to obtain WO x / Carrier solution.
[0037] Step 3: Weigh the sodium titanate additive according to the loading amount and disperse it in ethanol, then transfer the sodium titanate ethanol dispersion to the WO prepared in step 2. x / carrier solution, stirred continuously at 90°C until uniformly dispersed, then dried, and calcined at 600°C in air atmosphere to obtain 1Na2TiO3-WO x / vector.
[0038] Step 4: weigh the Na2TiO3-WO prepared in step 3 x / The carrier is spread flat on the surface dish, and then the chloroplatinic acid aqueous solution is measured according to the loading amount and dropped into the surface dish to immerse the Na2TiO3-WO x / carrier, and then dried at room temperature for 10 h, and calcined at 400 °C in air atmosphere to obtain Pt-1Na2TiO3-WO x / support. Catalyst XRD characterization see attached Figure 1 .
[0039] Example 2
[0040] A catalyst for preparing 1,3-propylene glycol by hydrogenating glycerol, the catalyst comprising Pt, W, an auxiliary agent and a carrier, wherein the loading amount of Pt is 2% of the catalyst mass, the loading amount of W is 10% of the carrier mass, the loading amount of the auxiliary agent is 2% of the carrier mass, the auxiliary agent is Na2TiO3, and the carrier is a mixture of ZrO2, TiO2 and Al2O3, wherein the W ZrO2 :w TiO2 :w Al2O3 =7:1:2.
[0041] The preparation method of the catalyst specifically comprises the following steps:
[0042] Step 1: Weigh zirconium oxychloride, tetrabutyl titanate and aluminum chloride according to the ratio, dissolve them in ethanol, and stir at 60° C. for 90 minutes to obtain a carrier solution.
[0043] Step 2: Weigh the W precursor according to the loading amount and dissolve it in ethanol. Then transfer the W-containing ethanol solution to the carrier solution prepared in step 1 and stir at 60°C for 90 min to obtain WO x / Carrier solution.
[0044] Step 3: Weigh the sodium titanate additive according to the loading amount and disperse it in ethanol, then transfer the sodium titanate ethanol dispersion to the WO prepared in step 2. x / carrier solution, stirred continuously at 90°C until uniformly dispersed, then dried, and calcined at 600°C in air atmosphere to obtain 2Na2TiO3-WO x / vector.
[0045] Step 4: weigh the Na2TiO3-WO prepared in step 3 x / The carrier is spread flat on the surface dish, and then the chloroplatinic acid aqueous solution is measured according to the loading amount and dropped into the surface dish to immerse the Na2TiO3-WO x / carrier, and then dried at room temperature for 10 h, and calcined at 400 °C in air atmosphere to obtain Pt-2Na2TiO3-WO x / Support. Catalyst XRD characterization see attached Figure 1 The acidity characterization results of the catalyst are shown in the attached Figure 2 From the figure, it can be seen that the catalyst surface is easy to produce Lewis acid and Bronsted acid under hydrogen treatment, which improves the catalytic activity.
[0046] Example 3
[0047] A catalyst for preparing 1,3-propylene glycol by hydrogenating glycerol, the catalyst comprising Pt, W, an auxiliary agent and a carrier, wherein the loading amount of Pt is 2% of the catalyst mass, the loading amount of W is 10% of the carrier mass, the loading amount of the auxiliary agent is 3% of the carrier mass, the auxiliary agent is Na2TiO3, and the carrier is a mixture of ZrO2, TiO2 and Al2O3, wherein the W ZrO2 :w TiO2 :w Al2O3 =7:1:2.
[0048] The preparation method of the catalyst specifically comprises the following steps:
[0049] Step 1: Weigh zirconium oxychloride, tetrabutyl titanate and aluminum chloride according to the ratio, dissolve them in ethanol, and stir at 60° C. for 90 minutes to obtain a carrier solution.
[0050] Step 2: Weigh the W precursor according to the loading amount and dissolve it in ethanol. Then transfer the W-containing ethanol solution to the carrier solution prepared in step 1 and stir at 60°C for 90 min to obtain WO x / Carrier solution.
[0051] Step 3: Weigh the sodium titanate additive according to the loading amount and disperse it in ethanol, then transfer the sodium titanate ethanol dispersion to the WO prepared in step 2. x / carrier solution, stirred continuously at 90 °C until uniformly dispersed, then dried, and calcined at 600 °C in air atmosphere to obtain 3Na2TiO3-WO x / vector.
[0052] Step 4: weigh the Na2TiO3-WO prepared in step 3 x / The carrier is spread flat on the surface dish, and then the chloroplatinic acid aqueous solution is measured according to the loading amount and dropped into the surface dish to immerse the Na2TiO3-WO x / carrier, and then dried at room temperature for 10 h, and calcined at 400 °C in air atmosphere to obtain Pt-3Na2TiO3-WO x / support. Catalyst XRD characterization see attached Figure 1 The high-resolution electron microscopy results of the catalyst are shown in Figure 3 ,As can be seen from the figure, the addition of solid titanate is conducive to obtaining ,highly dispersed or even single atom distribution of Pt nano-species.
[0053] Example 4
[0054] A catalyst for preparing 1,3-propylene glycol by hydrogenating glycerol, the catalyst comprising Pt, W, an auxiliary agent and a carrier, wherein the loading amount of Pt is 2% of the catalyst mass, the loading amount of W is 10% of the carrier mass, the loading amount of the auxiliary agent is 2% of the carrier mass, the auxiliary agent is magnesium titanate, and the carrier is a mixture of ZrO2, TiO2 and Al2O3, wherein the WZrO2 :w TiO2 :w Al2O3 =7:1:2.
[0055] The preparation method of the catalyst specifically comprises the following steps:
[0056] Step 1: Weigh zirconium oxychloride, tetrabutyl titanate and aluminum chloride according to the ratio, dissolve them in ethanol, and stir at 60° C. for 90 minutes to obtain a carrier solution.
[0057] Step 2: Weigh the W precursor according to the loading amount and dissolve it in ethanol. Then transfer the W-containing ethanol solution to the carrier solution prepared in step 1 and stir at 60°C for 90 min to obtain WO x / Carrier solution.
[0058] Step 3: weigh the auxiliary agent magnesium titanate according to the loading amount and disperse it in ethanol, and then transfer the magnesium titanate ethanol dispersion to the WO prepared in step 2. x / carrier solution, stirred continuously at 90°C until uniformly dispersed, then dried, and calcined at 600°C in air atmosphere to obtain MgTiO3-WO x / vector.
[0059] Step 4: Weigh the MgTiO3-WO prepared in step 3 x / The carrier is spread flat on the surface dish, and then the chloroplatinic acid aqueous solution is measured according to the loading amount and dropped into the surface dish to immerse the MgTiO3-WO x / carrier, and then dried at room temperature for 10 h, and calcined at 400 °C in air atmosphere to obtain Pt-MgTiO3-WO x / support. Catalyst XRD characterization see attached Figure 1 .
[0060] Example 5
[0061] A catalyst for preparing 1,3-propylene glycol by hydrogenating glycerol, the catalyst comprising Pt, W, an auxiliary agent and a carrier, wherein the loading amount of Pt is 2% of the catalyst mass, the loading amount of W is 10% of the carrier mass, the loading amount of the auxiliary agent is 2% of the carrier mass, the auxiliary agent is lithium titanate, and the carrier is a mixture of ZrO2, TiO2 and Al2O3, wherein the W ZrO2 :w TiO2 :w Al2O3 =7:1:2.
[0062] The preparation method of the catalyst specifically comprises the following steps:
[0063] Step 1: Weigh zirconium oxychloride, tetrabutyl titanate and aluminum chloride according to the ratio, dissolve them in ethanol, and stir at 60° C. for 90 minutes to obtain a carrier solution.
[0064] Step 2: Weigh the W precursor according to the loading amount and dissolve it in ethanol. Then transfer the W-containing ethanol solution to the carrier solution prepared in step 1 and stir at 60°C for 90 min to obtain WO x / Carrier solution.
[0065] Step 3: weigh the auxiliary agent lithium titanate according to the loading amount and disperse it in ethanol, and then transfer the lithium titanate ethanol dispersion to the WO prepared in step 2. x / carrier solution, stirred continuously at 90°C until uniformly dispersed, then dried, and calcined at 600°C in air atmosphere to obtain MgTiO3-WO x / vector.
[0066] Step 4: Weigh the MgTiO3-WO prepared in step 3 x / The carrier is spread flat on the surface dish, and then the chloroplatinic acid aqueous solution is measured according to the loading amount and dropped into the surface dish to immerse the lithium titanate-WO x / carrier, and then dried at room temperature for 10 h, and calcined at 400 °C in air atmosphere to obtain Pt-lithium titanate-WO x / support. Catalyst XRD characterization see attached Figure 1 .
[0067] Example 6
[0068] A catalyst for preparing 1,3-propylene glycol by hydrogenating glycerol, the catalyst comprising Pt, W, an auxiliary agent and a carrier, wherein the loading amount of Pt is 1% of the catalyst mass, the loading amount of W is 10% of the carrier mass, the loading amount of the auxiliary agent is 2% of the carrier mass, the auxiliary agent is sodium titanate, and the carrier is a mixture of ZrO2, TiO2 and Al2O3, wherein the W ZrO2 :w TiO2 :w Al2O3 =7:1:2.
[0069] The preparation method of the catalyst specifically comprises the following steps:
[0070] Step 1: Weigh zirconium oxychloride, tetrabutyl titanate and aluminum chloride according to the ratio, dissolve them in ethanol, and stir at 60° C. for 90 minutes to obtain a carrier solution.
[0071] Step 2: Weigh the W precursor according to the loading amount and dissolve it in ethanol. Then transfer the W-containing ethanol solution to the carrier solution prepared in step 1 and stir at 60°C for 90 min to obtain WO x / Carrier solution.
[0072] Step 3: Weigh the sodium titanate additive according to the loading amount and disperse it in ethanol, then transfer the sodium titanate ethanol dispersion to the WO prepared in step 2. x / carrier solution, stirred continuously at 90°C until uniformly dispersed, then dried, and calcined at 600°C in air atmosphere to obtain sodium titanate-WO x / vector.
[0073] Step 4: Weigh the sodium titanate-WO prepared in step 3 x / The carrier is spread flat on a surface dish, and then a chloroplatinic acid aqueous solution is added dropwise to the surface dish according to the loading amount to immerse the sodium titanate-WO x / carrier, and then dried at room temperature for 10 h, and calcined at 400 °C in air atmosphere to obtain 1Pt-sodium titanate-WO x / support. Catalyst XRD characterization see attached Figure 1 .
[0074] Example 7
[0075] A catalyst for preparing 1,3-propylene glycol by hydrogenating glycerol, the catalyst comprising Pt, W, an auxiliary agent and a carrier, wherein the loading amount of Pt is 3% of the catalyst mass, the loading amount of W is 10% of the carrier mass, the loading amount of the auxiliary agent is 2% of the carrier mass, the auxiliary agent is Na2TiO3, and the carrier is a mixture of ZrO2, TiO2 and Al2O3, wherein the W ZrO2 :w TiO2 :w Al2O3 =7:1:2.
[0076] The preparation method of the catalyst specifically comprises the following steps:
[0077] Step 1: Weigh zirconium oxychloride, tetrabutyl titanate and aluminum chloride according to the ratio, dissolve them in ethanol, and stir at 60° C. for 90 minutes to obtain a carrier solution.
[0078] Step 2: Weigh the W precursor according to the loading amount and dissolve it in ethanol. Then transfer the W-containing ethanol solution to the carrier solution prepared in step 1 and stir at 60°C for 90 min to obtain WO x / Carrier solution.
[0079] Step 3: Weigh the sodium titanate additive according to the loading amount and dissolve it in ethanol, then transfer the sodium titanate ethanol solution to the WO prepared in step 2. x / carrier solution, stirred continuously at 90°C until uniformly dispersed, then dried, and calcined at 600°C in air atmosphere to obtain 2Na2TiO3-WO x / vector.
[0080] Step 4: weigh the Na2TiO3-WO prepared in step 3 x / The carrier is spread flat on the surface dish, and then the chloroplatinic acid aqueous solution is measured according to the loading amount and dropped into the surface dish to immerse the Na2TiO3-WO x / carrier, and then dried at room temperature for 10 h, and calcined at 400 °C in air atmosphere to obtain 3Pt-2Na2TiO3-WO x / support. Catalyst XRD characterization see attached Figure 1 .
[0081] Comparative Example 1
[0082] A catalyst for preparing 1,3-propylene glycol by hydrogenating glycerol, which differs from Example 1 of the present invention in that no auxiliary agent is added, and the rest is the same as Example 1 of the present invention. The XRD characterization of the prepared catalyst is shown in the attached Figure 1 .
[0083] Comparative Example 2
[0084] In order to illustrate that the chemical properties of titanate itself play a core role in the role of the auxiliary agent, and that the role of the auxiliary agent cannot be inferred by simple conjecture, this comparative example prepared a catalytic system composed of potassium titanate. The preparation method is the same as that of Example 1 of the present invention, except that the added component is potassium titanate, and the loading amount is 4% of the carrier mass. The XRD characterization of the prepared catalyst is shown in the attached Figure 1 .
[0085] The catalysts prepared in Examples 1 to 7 and Comparative Examples 1 to 2 of the present invention are used in the reaction of preparing 1,3-propylene glycol by hydrogenation of glycerol. The specific reaction conditions are as follows: the catalyst is placed in a constant temperature zone of a fixed bed reaction tube, activated for 1 hour at 250°C and 5MPa hydrogen atmosphere, then cooled to 145°C, and after the temperature is constant, the raw material is introduced under the conditions of a hydrogen pressure of 5MPa and a flow rate of 60mL / min. The raw material is a 30wt% glycerol aqueous solution, and the catalyst mass is 3.6g. After the reaction is completed, the liquid phase product is collected and analyzed by liquid chromatography. The reaction results are shown in Table 1.
[0086] Glycerol conversion rate = (initial moles of glycerol - remaining moles of glycerol) / initial moles of glycerol × 100%
[0087] Product selectivity = moles of carbon in a certain product / moles of carbon in glycerol conversion × 100%.
[0088] Note: EtOH: ethanol; n-PO: n-propanol; i-PO: isopropanol; 1,3-PDO: 1,3-propylene glycol; 1,2-PDO: 1,2-propylene glycol.
[0089] Table 1 Glycerol conversion and product selectivity in 100-hour reaction evaluation
[0090]
[0091] The above experimental results show that the Pt-titanate-WO xThe catalyst with carrier realizes high efficiency catalysis of 10-50wt% glycerol aqueous solution under the conditions of reaction pressure of 3-5MPa and reaction temperature of 130-160°C. Moreover, the catalyst of the present invention directly introduces titanate solid particles in the preparation process, which is different from the conventional Pt-W catalyst used for selective preparation of 1,3-propylene glycol by hydrogenation of glycerol reported in the prior art, and has the advantages of high catalytic activity, high raw material conversion rate, high selectivity of target product, stable life, etc.
[0092] The above embodiments are merely explanations of the present invention, not limitations of the present invention. After reading this specification, those skilled in the art may make modifications to the embodiments without any creative contribution as needed. However, such modifications are protected by the patent law as long as they are within the scope of the claims of the present invention.
Claims
1. A catalyst, characterized in that The catalyst comprises Pt, W, an additive and a carrier, and the carrier is a mixture of ZrO2, TiO2 and Al2O3.
2. The catalyst according to claim 1, characterized in that The ZrO2 content accounts for 70-98% of the carrier mass, the TiO2 content accounts for 1-10% of the carrier mass, and the Al2O3 content accounts for 1-20% of the carrier mass.
3. The catalyst according to claim 1, characterized in that The auxiliary agent is one or more of zirconium titanate, sodium titanate, magnesium titanate, lithium titanate and calcium titanate.
4. The catalyst according to claim 1, characterized in that The Pt content accounts for 0.5-5% of the mass of the catalyst, the W content accounts for 3-15% of the mass of the catalyst, and the additive content accounts for 0.5-5% of the mass of the catalyst.
5. A method for preparing the catalyst as claimed in claim 1, characterized in that: It includes the following steps: Step 1, weigh zirconium oxychloride, tetrabutyl titanate, and aluminum chloride according to the ratio, dissolve them in ethanol, and stir at 60-90° C. for 30-90 minutes to obtain a carrier solution; Step 2: Weigh the W precursor according to the loading amount and dissolve it in ethanol, then transfer the W-containing ethanol solution to the carrier solution prepared in step 1, and stir at 60-90°C for 30-90 minutes to obtain WO x / carrier solution; Step 3: weigh the titanate additive according to the loading amount and disperse it in ethanol, and then transfer the titanate ethanol dispersion to the WO prepared in step 2. x / carrier solution, and then continuously stirred at a certain temperature until uniformly dispersed, and then dried, and calcined in a high-temperature air atmosphere to obtain titanate-WO x / carrier; Step 4: Weigh the titanate-WO prepared in step 3 x / The carrier is spread flat on a surface dish, and then a chloroplatinic acid aqueous solution is added dropwise to the surface dish according to the loading amount to immerse the titanate-WO x / carrier, standing at room temperature for 5 to 10 hours and then drying, and calcining at 400 to 600° C. in air atmosphere by solid phase reaction to obtain the catalyst as claimed in claim 1, namely Pt-titanate-WO x / carrier composite catalyst.
6. The preparation method according to claim 5, characterized in that: In the step 1, the mass ratio of zirconium oxychloride, tetrabutyl titanate and aluminum chloride is 70-98%: 1-10%: 1-20% calculated according to the mass ratio of zirconium oxide, titanium oxide and aluminum oxide; and / or, In step 2, the precursor of W is one or more of phosphotungstic acid, sodium tungstate, silicotungstic acid, ammonium phosphotungstate, and sodium phosphotungstate; the loading amount is 3-15% of the catalyst mass calculated as WO3; and / or, In step 3, the stirring temperature is 60-120° C., and the calcination temperature is between 500 and 800° C.; and / or, In the step 4, the loading amount of Pt is 0.5-5% of the mass of the catalyst.
7. A catalyst prepared according to any one of claims 5-6, characterized in that: It is Pt-titanate-WO x / carrier composite catalyst.
8. Use of the catalyst according to any one of claims 1 and 7 in the reaction of preparing 1,3-propylene glycol by hydrogenation of glycerol, characterized in that: The reaction conditions are as follows: reaction pressure of 3-5 MPa, reaction temperature of 130-160° C., and reaction raw material of 10-70 wt % glycerol aqueous solution.
9. The use according to claim 8, characterized in that The reaction is carried out in a fixed bed reactor.
10. The use according to claim 8, characterized in that The catalyst can improve the glycerol conversion rate while maintaining the selectivity of 1,3-propylene glycol in the hydrogenation product without reducing, and inhibits the generation of 1,2-propylene glycol.