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CN-122006760-A - Nano rod-shaped Keggin type heteropolyacid catalyst and preparation method and application thereof

CN122006760ACN 122006760 ACN122006760 ACN 122006760ACN-122006760-A

Abstract

The invention belongs to the technical field of catalysts, and discloses a nano rod-shaped Keggin type heteropolyacid catalyst, a preparation method and application thereof, wherein the nano rod-shaped Keggin type heteropolyacid catalyst has a double rod-shaped structure, and the double rod-shaped structure is a rod-shaped structure with the lengths of 50-150nm and 3-10 mu m respectively. The heteropoly acid catalyst has the characteristics of large specific surface area, double rod-shaped structure and the like, and can optimize the reaction performance of the catalyst for preparing methacrylic acid by oxidizing methacrolein.

Inventors

  • ZHANG LINA
  • LIU XIAOLING
  • WU SANMIN
  • LIU DONGBING
  • LI WEI

Assignees

  • 中国石油化工股份有限公司
  • 中石化(北京)化工研究院有限公司

Dates

Publication Date
20260512
Application Date
20241112

Claims (10)

  1. 1. The nano rod-shaped Keggin type heteropolyacid catalyst is characterized by having a double rod-shaped structure, wherein the double rod-shaped structure is a rod-shaped structure with the length of 50-150nm and the length of 3-10 mu m respectively.
  2. 2. The nano rod-shaped Keggin type heteropolyacid catalyst according to claim 1, wherein the double rod-shaped structure is a rod-shaped structure with the length of 50-100nm and 4-9 ρm respectively, and the specific surface area of the heteropolyacid catalyst is 15-30m 2 /g, preferably 20-30m 2 /g.
  3. 3. The nanorod-shaped Keggin-type heteropolyacid catalyst according to claim 1, wherein the composition of the heteropolyacid catalyst is a a B b AsP x V y Mo 12 O z , wherein As, P, V, mo, O represents arsenic element, phosphorus element, vanadium element, molybdenum element and oxygen element, respectively, a is at least one of iron element, cobalt element, nickel element, zinc element, chromium element, copper element, manganese element, germanium element, bismuth element, zirconium element, silver element, gallium element, tungsten element and lanthanoid element other than promethium element, B is alkali metal element and/or NH 4 + , a, B, x, y and z are atomic ratios of the respective elements, wherein a is 0 to 3, preferably 0.5 to 3, B is 0 to 3, preferably 0.5 to 3, x is 0.5 to 3, preferably 1, y is 0 to 3, preferably 1, z is an atomic ratio of oxygen element required to satisfy the valence of the respective components.
  4. 4. The nanorod-shaped Keggin-type heteropoly acid catalyst according to claim 3, wherein A is copper element and zinc element, wherein the atomic ratio of copper element to As is 0.2-1.4:1, and the atomic ratio of zinc element to Zn/As is 0.3-1.6:1.
  5. 5. The nanorod-shaped Keggin-type heteropoly acid catalyst according to claim 3, wherein the alkali metal element is selected from at least one of sodium element, potassium element, rubidium element and cesium element.
  6. 6. The method for preparing the nano rod-shaped Keggin type heteropolyacid catalyst according to any one of claims 1 to 5, which is characterized by comprising the following steps: 1) Dissolving a phosphorus source, a molybdenum source and a vanadium source in deionized water, and reacting at 80-100 ℃ to form a solution; 2) Adding an alkali metal source and/or an ammonium source, an arsenic source and a transition metal source into the solution obtained in the step 1), and reacting at 0-80 ℃ to obtain a heteropolyacid solution; 3) Drying and roasting the heteropoly acid solution to obtain the nano rod-shaped Keggin type heteropoly acid catalyst; preferably, in the step 2), a solution formed by dissolving an alkali metal source and/or an ammonium source in deionized water is added into the solution obtained in the step 1) for reaction, and then a solution formed by dissolving an arsenic source and a transition metal source in deionized water is added for reaction to obtain a heteropolyacid solution.
  7. 7. The preparation method of the nanorod-shaped Keggin-type heteropoly acid catalyst according to claim 6, wherein in the step 1), the reaction temperature is 90-100 ℃, and the reaction time is 3-10h; in the step 2), the reaction temperature is 30-70 ℃ and the reaction time is 4-48h; the reflux stirring reaction is adopted in the step 1) and the step 2), and the stirring speed is 300-800r/min, preferably 400-600r/min, and more preferably 500r/min.
  8. 8. The preparation method of the nanorod-shaped Keggin-type heteropolyacid catalyst according to claim 6, wherein in the step 3), the drying mode is at least one of spray drying, spin drying and freeze drying, preferably spray drying and or spin drying, the spray drying temperature is 100-220 ℃, preferably 150-200 ℃, the spin drying temperature is 30-80 ℃, preferably 40-60 ℃, and the vacuum degree is 50-150mbar, preferably 80-110mbar; the calcination temperature is 350-400 ℃, preferably 380 ℃, for 3-5 hours, preferably 4 hours.
  9. 9. The preparation method of the nanorod-shaped Keggin-type heteropoly acid catalyst according to claim 6, wherein the molar ratio of the phosphorus source to the molybdenum source to the vanadium source is 0.5-3:12:0-3, preferably 1:12:1, calculated by phosphorus element, molybdenum element and vanadium element; The alkali metal source is at least one of a sodium source, a potassium source, a rubidium source and a cesium source, the arsenic source is arsenic acid, the transition metal source is at least one of an iron source, a cobalt source, a nickel source, a zinc source, a chromium source, a copper source, a manganese source, a germanium source, a bismuth source, a zirconium source, a silver source, a gallium source, a tungsten source and a lanthanide metal source except promethium, and the molar ratio of the alkali metal source and/or the ammonium source to the arsenic source to the transition metal source is 0-3:1:0-3, preferably 0.5-3:1:0.5-3; the mole ratio of the molybdenum source to the arsenic source is 12:1 based on molybdenum element and arsenic element.
  10. 10. The use of the nanorod-shaped Keggin-type heteropoly acid catalyst according to any one of claims 1-5 in the preparation of alkenoic acid by enal oxidation; Preferably, the enal is methacrolein; Preferably, the conditions of the oxidation reaction include a temperature of 280-320 ℃ and a weight space velocity of the enal of 600-1600h -1 .

Description

Nano rod-shaped Keggin type heteropolyacid catalyst and preparation method and application thereof Technical Field The invention belongs to the technical field of catalysts, and particularly relates to a nanorod-shaped Keggin-type heteropoly acid catalyst, a preparation method of the nanorod-shaped Keggin-type heteropoly acid catalyst and application of the nanorod-shaped Keggin-type heteropoly acid catalyst. Background Methyl Methacrylate (MMA) is an important chemical monomer, and is mainly used for preparing polymethyl methacrylate (PMMA) of organic glass, so that the market demand is large. The traditional preparation method of MMA is an acetone cyanohydrin method, and in recent years, the route is limited by environmental protection due to the fact that the method involves extremely toxic hydrocyanic acid and generates a large amount of waste sulfuric acid, and compared with the acetone cyanohydrin method, the C4 method which takes isobutene as a raw material has the characteristics of small environmental pollution, low cost and good economic benefit, so that the method becomes a research hot spot in recent years. The C4 method is divided into three steps, wherein the first step is that isobutene is oxidized to prepare methacrolein, the second step is that the methacrolein is oxidized to prepare methacrylic acid, and the third step is that the methacrylic acid and methanol are esterified to prepare MMA. The research and development core of the process is a catalyst of the second step, and the current research shows that the catalyst of the second step is a Keggin type heteropolyacid catalyst, the specific surface area of the catalyst has great influence on the performance of the catalyst, and the catalyst has large specific surface area, more active components which can be exposed and better reaction activity. Therefore, the preparation of the heteropolyacid catalyst with large specific surface area is significant. Nanomaterial generally refers to a material having at least one dimension in three dimensions in a nano-size (1-100 nm) or being composed of them as a basic unit, and a nanocatalyst has a larger specific surface area than other catalysts. Disclosure of Invention Based on the above situation, in order to overcome the problem of low specific surface area of the Keggin type heteropoly acid catalyst in the prior art, the invention aims to provide a nano rod-shaped Keggin type heteropoly acid catalyst, a preparation method and application thereof, and the heteropoly acid catalyst has the characteristics of large specific surface area, double rod-shaped structure and the like, can optimize the reaction performance of the catalyst for preparing methacrylic acid by oxidizing methacrolein, and shows good methacrolein conversion rate and methacrylic acid selectivity. The first aspect of the present invention provides a nanorod-shaped Keggin-type heteropolyacid catalyst having a double-rod-shaped structure, wherein the double-rod-shaped structure is a rod-shaped structure with the length of 50 omega 150nm and the length of 3-10 μm respectively. The second aspect of the invention provides a preparation method of the nanorod-shaped Keggin-type heteropoly acid catalyst, which comprises the following steps: 1) Dissolving a phosphorus source, a molybdenum source and a vanadium source in deionized water, and reacting at 80-100 ℃ to form a solution; 2) Adding an alkali metal source and/or an ammonium source, an arsenic source and a transition metal source into the solution obtained in the step 1), and reacting at 0-80 ℃ to obtain a heteropolyacid solution; 3) And drying and roasting the heteropoly acid solution to obtain the nano rod-shaped Keggin type heteropoly acid catalyst. The third aspect of the invention provides an application of the nanorod-shaped Keggin-type heteropoly acid catalyst in preparation of olefine acid by olefine aldehyde oxidation. Compared with the prior art, the technical scheme of the invention has the following steps: (1) The catalyst provided by the invention has higher olefine aldehyde conversion rate and olefine acid selectivity in the process of preparing olefine acid by oxidizing olefine aldehyde, and particularly has higher methacrolein conversion rate and methacrylic acid selectivity in the process of preparing methacrylic acid by oxidizing methacrolein. (2) By adopting the method disclosed by the invention, the morphology and specific surface area of the heteropoly acid catalyst can be effectively regulated and controlled through low-temperature synthesis. The method provided by the invention is simple to operate, good in repeatability and good in economy, and is beneficial to realizing industrial application. Additional features and advantages of the invention will be set forth in the detailed description which follows. Drawings FIG. 1 is an SEM image of a sample obtained in example 1. Fig. 2 is an SEM image of the sample obtained in example 1. FIG. 3 is a nitrogen adsorptio