A catalyst for the catalytic cracking of 2-cyanopyridine distillation residues to prepare pyridine-2-carboxamide and its preparation method.

Abstract

A catalyst for the catalytic cracking of 2-cyanopyridine distillation residues to prepare pyridine-2-carboxamide and its preparation method thereof are disclosed. The catalyst involves impregnating silicates or aluminosilicates, including zeolites, silica gel, and molecular sieves, with an aqueous solution containing phosphoric acid and phosphotungstic acid. This impregnation process creates Ha on the surface and pores of the silicates or aluminosilicates. + Doping creates more acidic activation sites on the surface or in the channels of silicates or aluminosilicates; this is achieved by increasing the H content on the surface and in the channels. + The silicates or aluminosilicates doped with materials such as zeolite, silica gel, and molecular sieves are subjected to high-temperature calcination to obtain a silica-oxygen-supported acid catalyst with silicate or aluminosilicate materials such as zeolite, silica gel, and molecular sieves as the carrier and phosphoric acid / silicic acid / phosphotungstic acid / silicotungstic acid and / or phosphosilicate as the active components.

Description

Technical Field

[0001] The present invention relates to a catalyst for the catalytic cracking of 2-cyanopyridine distillation residue to prepare pyridine-2-carboxamide and its preparation method, which is a fine chemical with selective catalytic cracking function and its preparation in the field of new materials. Background Technology

[0002] 2-Cyanopyridine, abbreviated as 2-OP, also known as pyridine-2-carboxynitrile or 2-pyridinecarboxynitrile, with CAS number 100-70-9, is a pyridine derivative with a melting point of 24–27°C and a boiling point of 212–215°C / 760 mmHg. As an important intermediate in fine organic synthesis, 2-cyanopyridine is widely used in the production of various pharmaceuticals, pesticides, and dyes. For example, it is indispensable in the synthesis of the agricultural herbicide 4-amino-3,5,6-trichloropyridine-2-carboxylic acid (toxaphene) and the Xa factor inhibitor betriciban. The main preparation methods of 2-cyanopyridine are as follows: (1) 2-methylpyridine catalytic ammonia oxidation method, which is essentially to convert 2-methylpyridine directly into 2-cyanopyridine by catalytic oxidation, amination and dehydration reaction under the conditions of 300-500℃ and in the presence of a catalyst, using a mixture of ammonia and oxygen as oxidant; (2) cyano substitution method, which is essentially to convert 2-halopyridine into 2-cyanopyridine by reacting 2-halopyridine with acetone cyanohydrin, inorganic alkali metal cyanide, etc., to achieve the substitution of halogen atom by cyano group; (3) pyridine-2-carboxaldehyde oxime method, which is essentially to directly dehydrate 2-cyanopyridine in the presence of dehydrating agent using pyridine-2-carboxaldehyde oxime as raw material; (4) 2-aminopyridine method, which is essentially to convert 2-aminopyridine into pyridine diazonium salt by diazotization reaction, and then to obtain 2-cyanopyridine by Sandmeyer reaction of pyridine diazonium salt with cuprous cyanide. Among these methods, the 2-methylpyridine-catalyzed ammonia oxidation method for preparing 2-cyanopyridine is more widely used in actual production due to its advantages such as sufficient raw material sources, no involvement of highly toxic cyanides, and relatively low product preparation costs. In fact, the existing industrial production processes for 2-cyanopyridine are all based on the 2-methylpyridine-catalyzed ammonia oxidation process.

[0003] Pyridine-2-carboxamide, also known as 2-pyridineamide or 2-amidopyridine, CAS number 1452-77-3, is an aromatic heteroamide with a melting point of 110℃ and a boiling point of 143℃ / 20mmHg. It is a white crystalline solid at room temperature. As an intermediate, pyridine-2-carboxamide can be used to synthesize 2-aminopyridine, L-piperidine-2-carboxylic acid, pyridine-2-carboxysulfonate, and 2-piperidinecarboxamide. As a polydentate ligand containing an amide group, pyridine-2-carboxamide forms complexes with metal ions that interact strongly with nucleic acids and exhibit certain anticancer activity. The bispyridinediamide generated by the coupling reaction of pyridine-2-carboxamide has excellent extraction performance for uranium and thorium, and can be used for the separation and recovery of radioactive elements such as uranium and thorium. The bispyridine diamide generated by the coupling reaction of pyridine-2-carboxamide forms metal complexes with Fe(III), Ni(II), and Mn(III), which have a structure similar to metalloporphyrins and can be used as catalysts for the synthesis of various fine chemicals. The preparation of pyridine-2-carboxamide mainly includes the following methods: (1) pyridine-2-carboxaldehyde method, which is essentially the direct reaction of pyridine-2-carboxaldehyde with hydroxylamine hydrochloride in the presence of a catalyst to obtain pyridine-2-carboxaldehyde oxime, and then the pyridine-2-carboxaldehyde oxime is rearranged to generate pyridine-2-carboxamide; (2) pyridine-2-carboxynitrile method, which is essentially the incomplete hydrolysis of pyridine-2-carboxynitrile in the presence of a catalyst to generate pyridine-2-carboxamide; (3) 2-methylpyridine method, which is essentially the first oxidation of 2-methylpyridine to generate pyridine-2-carboxylic acid, and then acylation and amination to obtain pyridine-2-carboxamide. These methods for preparing pyridine-2-carboxamide often suffer from drawbacks such as high raw material costs or complex processes.

[0004] In the process of preparing 2-cyanopyridine from 2-methylpyridine via catalytic ammoxidation, the following reaction mechanisms may exist: First, 2-methylpyridine is oxidized to pyridine-2-carboxaldehyde under catalysis, then pyridine-2-carboxaldehyde reacts with ammonia to form pyridine-2-methylimine, which is then oxidized and dehydrogenated to 2-cyanopyridine. Second, 2-methylpyridine is oxidized to pyridine-2-carboxaldehyde under catalysis, then further oxidized to pyridine-2-carboxylic acid, which then reacts with ammonia at high temperature to form pyridine-2-carboxamide, which is then dehydrated at high temperature to 2-cyanopyridine. Both pyridine-2-carboxaldehyde and pyridine-2-carboxamide may undergo oxidative coupling during the high-temperature catalytic ammoxidation process, resulting in bimolecular, tripolecular, or multimolecular polymerization, thus producing substances with boiling points much higher than 2-cyanopyridine.

[0005] In practice, the process of producing 2-cyanopyridine from 2-methylpyridine via catalytic ammonia oxidation involves distilling the resulting oxidized liquid to obtain high-quality 2-cyanopyridine. This distillation process generates a large amount of residue, approximately 10% to 15% of the 2-cyanopyridine yield. Current methods for treating this residue as hazardous solid waste involve high-temperature incineration followed by landfill or mineralization. This approach not only consumes significant amounts of energy but also often fails to truly render the distillation residue harmless. Meanwhile, based on the analysis of the process of preparing 2-cyanopyridine by catalytic ammoxidation of 2-methylpyridine, organic compounds such as pyridine-2-carboxamide, pyridine-2-carboxaldehyde, and pyridine-2-carboxylic acid, or their high-temperature polymers, may be present in its distillation residue. Whether it is pyridine-2-carboxyl, pyridine-2-carboxaldehyde, or pyridine-2-carboxylic acid, they are all important intermediates in fine organic synthesis. Therefore, treating this distillation residue by direct high-temperature incineration is also a waste of resources.

[0006] This invention relates to a catalyst and its preparation method for the catalytic cracking of 2-cyanopyridine distillation residues to prepare pyridine-2-carboxamide. The aim is to develop a catalyst that uses silicate or aluminosilicate materials as a support, and phosphoric acid / silicic acid / phosphotungstic acid / silicotungstic acid and / or phosphosilicate as active components. This catalyst can selectively convert substances present in the 2-cyanopyridine distillation process residues into pyridine-2-carboxamide at a certain temperature, thereby achieving high-value resource utilization of the 2-cyanopyridine distillation process residues. The catalyst preparation method belongs to the field of new materials and is a preparation technology for materials with directional catalytic function.

[0007] In the research and development of a catalyst and its preparation method for the catalytic cracking of 2-cyanopyridine distillation residue to prepare pyridine-2-carboxamide, I came across a lot of technical information on the preparation of pyridine-2-carboxynitrile and pyridine-2-carboxamide, as well as catalytic cracking reactions and their directional and selective catalyst preparation. Among them, the main reference materials with certain reference value include: "Catalytic pyrolysis and liquefaction behavior of microalgae for bio-oil production" (Bioresource technology, 2020, 300) and "Production of acetonitrile via catalytic fast pyrolysis of biomass derived polylactic acid under ammoniaatmosphere" (Journal of Analytical and Applied Chemicals). Pyrolysis, 2019, 140), Selective oxidative cleavage of carbon-carbon double bonds and selective oxidation of sp-3 C-H bonds in olefins under co-catalysis of iron and sulfur radicals with oxygen participation (Chongqing University, 2018), Preparation of N-vinylformamide by catalytic cleavage of ethylenedicarboxamide (Journal of Qingdao University of Science and Technology (Natural Science Edition), 2017, 38(02): 34-37), A comparative study on the catalytic effect of H-ZSM5 on upgrading of pyrolysis vapors derived from lignocellulosic and proteinaceous biomass (Fuel, 2016, 166), Study on a new process for the synthesis of N,N-dimethylacrylamide by catalytic cleavage (Journal of Zhejiang University of Technology, 2008(03): 265-267), Transition metal-free synthesis of primary amides from aldehydes and hydroxylamine "Hydrochloride" (Tetrahedron Letters, 2014, Vol.55, No.20), "Synthesis of 4-(4-aminophenoxy)-N-methyl-2-pyridinecarboxamide" (Journal of Hebei Normal University / Natural Science Edition, 2017, Vol.41, No.3), "Study on a New Synthetic Method of 5-Bromo-2-cyanopyridine" (Fine Chemical Intermediates, 2016, Vol.46, No.).2) Synthesis of N-alkyl-4-chloro-2-pyridinecarboxamide (Chemical World, 2011, Vol.52, No.1), Study on Gas-Solid Phase Catalysis of Ammonia Oxidation to Synthesize 2-Cyanopyridine using V-Ti-O-Mo Catalyst (Journal of Chemical Engineering of Chinese Universities, 2016, Vol.30, No.4), Synthesis of Aminopyridine (Journal of Zhejiang University (Engineering Science), 2006, Vol.40, No.7), Synthesis of Pyridineamide and Performance Study on Extraction of U(VI) (Nuclear Chemistry and Radiochemistry, 2004, Vol.26, No.3), Spectroscopic Study on the Interaction of Pyridineamide with DNA (Spectroscopy and Spectral Analysis, 2008, Vol.28, No.6), Hydrolysis Kinetics of 2-Pyridinecarboxamide, 3-Pyridinecarboxamide and 4-Pyridinecarboxamide in High-Temperature Water (Chinese Journal of Chemical Industry). Published in journals including: Engineering, 2014, Vol.22, No.9; "Application Prospects of Cyanopyridine in Pesticide Chemicals" (New Century of Agrochemicals, 2008, No.5); "Gas Chromatographic Analysis of 2-Cyanopyrazine in Aqueous Solutions" (Fine Chemical Intermediates, 2004, Vol.34, No.4); "Schematic Diagram of the Synthetic Route of Pabuciclovir" (China Pharmaceutical Industry Journal, 2017, Vol.48, No.5); "Ammonia Oxidation Catalytic Synthesis of 2-Cyanopyrazine" (Journal of Chemistry and Chemical Engineering, 2005, Vol.19, No.6); and "Ammoxidation of 2-picoline catalyzed by modified V2O5 / TiO2" (Monatshefie fürchemie-chemical monthly, 2014, Vol.145, No.8). Summary of the Invention

[0008] This invention discloses a catalyst and its preparation method for the catalytic cracking of 2-cyanopyridine distillation residues to prepare pyridine-2-carboxamide. The main purpose is to address the need for a catalyst capable of selectively and efficiently cracking distillation residues in the catalytic ammoxidation process for producing pyridine-2-carboxynitrile, thereby reducing its volume and yielding pyridine-2-carboxamide in high quantities. Furthermore, this invention aims to improve the atom economy of feedstocks in the catalytic ammoxidation process of 2-methylpyridine to pyridine-2-carboxynitrile, thus supporting the efficient utilization of resources.

[0009] First, silicates or aluminosilicates, including zeolites, silica gel, and molecular sieves, are impregnated with an aqueous solution containing phosphoric acid and phosphotungstic acid. This process replaces the metal ions on the surface of these silicates or aluminosilicates with hydrogen ions, and introduces phosphoric acid or phosphotungstic acid components, ultimately achieving surface doping or pore doping of these silicates or aluminosilicates, thereby forming more acidic activation sites on their surface or in their pores. Then, through high-temperature calcination, a solid catalyst is obtained with silicate or aluminosilicate materials as the support and phosphoric acid / silicic acid / phosphotungstic acid / silicotungstic acid and / or phosphosilicate as the active components.

[0010] When the catalyst obtained by the method of the invention is used to treat the distillation residue formed in the catalytic ammonia oxidation process of 2-methylpyridine under appropriate conditions, the residue can be selectively decomposed into a material with pyridine-2-carboxamide as the main component. By combining in-situ distillation and crystallization / recrystallization techniques with the obtained catalytically decomposed material, a pyridine-2-carboxamide product with a mass percentage content ≥97% can be obtained in a yield of more than 80% relative to the distillation residue. Attached Figure Description

[0011] Figure 1 This is a structural diagram of pyridine-2-carboxamide involved in the invention.

[0012] Figure 2 FTIR spectrum of pyridine-2-carboxamide

[0013] Figure 3 The image shows the 1H NMR spectrum of pyridine-2-carboxamide.

[0014] Figure 4 The XRD patterns are shown for the siloxy-supported acid catalysts obtained by calcination at different temperatures. Specific implementation methods

[0015] The invention relates to a catalyst and its preparation method for the catalytic cracking of 2-cyanopyridine distillation residues to prepare pyridine-2-carboxamide. The catalyst is characterized by using silicates or aluminosilicates, including zeolites, silica gel, and molecular sieves, as supports. The supports are impregnated with an aqueous solution containing phosphoric acid and / or phosphotungstic acid to achieve H+ doping on the surface and pores of the silicates or aluminosilicates, thereby forming more acidic activation sites on the surface or pores. The surface- and pore-doped silicates or aluminosilicates, including zeolites, silica gel, and molecular sieves, are then subjected to high-temperature calcination to obtain a siloxy-based supported acid catalyst with silicate or aluminosilicate materials, including zeolites, silica gel, and molecular sieves, as supports, and phosphoric acid / silicic acid / phosphotungstic acid / phosphotungstic acid and / or phosphosilicate as active components. The relevant process parameters are as follows:

[0016] Zeolites including 4A zeolite, mordenite, and / or HZSM-5 zeolite, silica gel including primary silica gel, color-changing silica gel, silica gel H and / or silica gel G, or molecular sieves including 3A (potassium A type), 4A (sodium A type), 5A (calcium A type), 10Z (calcium Z type), 13Z (sodium Z type) and / or Y (sodium Y type) are impregnated in an aqueous solution containing phosphoric acid and phosphotungstic acid. The mass percentage concentration of phosphoric acid in the aqueous solution is 10% to 80%, the mass percentage concentration of phosphotungstic acid is 0.0001% to 1.0%, the mass ratio of zeolite, silica gel or molecular sieve to the aqueous solution containing phosphoric acid and phosphotungstic acid is 1.0:1.0 to 100, and the impregnation time is 2 to 48 hours. The impregnated material is filtered, the impregnation liquid is recovered, and the resulting solid is placed in a muffle furnace at 300℃~800℃ and calcined for 2~12 hours. The calcined solid is then pulverized to obtain the siloxy-supported acid catalyst. After determining the phosphoric acid and phosphotungstic acid content in the recovered impregnation liquid, appropriate amounts of phosphoric acid and phosphotungstic acid are added according to the catalyst preparation process requirements to meet the requirements for recycling.

[0017] Example 1

[0018] A catalyst for the catalytic cracking of 2-cyanopyridine distillation residue to prepare pyridine-2-carboxamide and its preparation method thereof, comprising the following steps:

[0019] Step 1: Dissolve the measured amounts of phosphoric acid and phosphotungstic acid in deionized water to obtain an aqueous solution containing phosphoric acid and phosphotungstic acid with a mass percentage concentration of 30% and a mass percentage concentration of 0.0010%.

[0020] Step 2: 4A zeolite, mordenite, and / or HZSM-5 zeolite are impregnated in an aqueous solution containing phosphoric acid and phosphotungstic acid at a mass ratio of 1.0:10. After 12.0 hours, the liquid phase is removed by filtration. The resulting solid is then calcined in a muffle furnace at 500°C for 6.0 hours. The calcined solid is then pulverized to a particle size of 50-300 mesh to obtain the zeolite-supported acid catalyst.

[0021] Example 2

[0022] Step 1: Dissolve the measured amounts of phosphoric acid and phosphotungstic acid in deionized water to obtain an aqueous solution containing phosphoric acid and phosphotungstic acid with a mass percentage concentration of 40% and a mass percentage concentration of 0.010%.

[0023] Step 2: The original silica gel, color-changing silica gel, silica gel H and / or silica gel G are impregnated in the aqueous solution containing phosphoric acid and phosphotungstic acid at a mass ratio of silica gel to an aqueous solution containing phosphoric acid and phosphotungstic acid of 1.0:20. After 15.0 hours, the liquid phase is removed by filtration, and the resulting solid is placed in a muffle furnace at 600°C and calcined for 12.0 hours. The solid material after high-temperature calcination is then pulverized to a particle size of 50-300 mesh to obtain the silica gel supported acid catalyst.

[0024] Example 3

[0025] Step 1: Dissolve the measured amounts of phosphoric acid and phosphotungstic acid in deionized water to obtain an aqueous solution containing phosphoric acid and phosphotungstic acid with a mass percentage concentration of 50% and a mass percentage concentration of 0.010%.

[0026] Step 2: Molecular sieves 3A (potassium A type), 4A (sodium A type), 5A (calcium A type), 10Z (calcium Z type), 13Z (sodium Z type) and / or Y (sodium Y type) are impregnated in an aqueous solution containing phosphoric acid and phosphotungstic acid at a mass ratio of 1.0:30. After 18.0 hours, the liquid phase is removed by filtration, and the resulting solid is placed in a muffle furnace at 450°C and calcined for 24.0 hours. The calcined solid is then pulverized to a particle size of 50-300 mesh to obtain the molecular sieve-supported acid catalyst.

[0027] Example 4

[0028] A catalyst for the catalytic cracking of 2-cyanopyridine distillation residue to prepare pyridine-2-carboxamide and its preparation method thereof, comprising the following steps:

[0029] Step 1: Dissolve the measured amounts of phosphoric acid and phosphotungstic acid in deionized water to obtain an aqueous solution containing phosphoric acid and phosphotungstic acid with a mass percentage concentration of 60% and a mass percentage concentration of 0.00010%.

[0030] Step 2: Immerse 4A zeolite, mordenite, and / or HZSM-5 zeolite in an aqueous solution containing phosphoric acid and phosphotungstic acid at a mass ratio of 1.0:50. After 8.0 hours, filter to remove the liquid phase, and place the resulting solid in a muffle furnace at 700℃ for 10.0 hours. Then, pulverize the solid material after high-temperature calcination to a particle size of 50-300 mesh to obtain the zeolite-supported acid catalyst.

[0031] Example 5

[0032] Step 1: Dissolve the measured amounts of phosphoric acid and phosphotungstic acid in deionized water to obtain an aqueous solution containing phosphoric acid and phosphotungstic acid with a phosphoric acid mass percentage concentration of 20% and a phosphotungstic acid mass percentage concentration of 0.10%.

[0033] Step 2: The original silica gel, color-changing silica gel, silica gel H and / or silica gel G are impregnated in the aqueous solution containing phosphoric acid and phosphotungstic acid at a mass ratio of silica gel to an aqueous solution containing phosphoric acid and phosphotungstic acid of 1.0:80. After 24.0 hours, the liquid phase is removed by filtration, and the resulting solid is placed in a muffle furnace at 800°C and calcined for 5.0 hours. The calcined solid is then pulverized to a particle size of 50-300 mesh to obtain the silica gel supported acid catalyst.

[0034] Example 6

[0035] Step 1: Dissolve the measured amounts of phosphoric acid and phosphotungstic acid in deionized water to obtain an aqueous solution containing phosphoric acid and phosphotungstic acid with a mass percentage concentration of 10% and a mass percentage concentration of 0.10%.

[0036] Step 2: Molecular sieves 3A (potassium A type), 4A (sodium A type), 5A (calcium A type), 10Z (calcium Z type), 13Z (sodium Z type) and / or Y (sodium Y type) are impregnated in an aqueous solution containing phosphoric acid and phosphotungstic acid at a mass ratio of 1.0:80. After 24.0 hours, the liquid phase is removed by filtration, and the resulting solid is placed in a muffle furnace at 800℃ and calcined for 12.0 hours. The calcined solid is then pulverized to a particle size of 50-300 mesh to obtain the molecular sieve-supported acid catalyst.

Claims

1. A method for preparing pyridine-2-carboxamide by catalytic cracking of 2-cyanopyridine distillation residue, characterized in that: By impregnating silicates or aluminosilicates, including zeolites and molecular sieves, with an aqueous solution containing phosphoric acid and phosphotungstic acid, H2O is achieved on the surface and in the channels of silicates or aluminosilicates. + Doping, thereby forming more acidic activation sites on the surface or channels of silicates or aluminosilicates; by increasing the H on the surface or channels + The silicates or aluminosilicates doped with zeolites or molecular sieves are calcined at high temperature to obtain a siloxy-supported acid catalyst with zeolite or molecular sieve silicate or aluminosilicate material as the support and phosphoric acid / silicic acid / phosphotungstic acid / silicotungstic acid and / or phosphosilicate as the active components. In the aqueous solution containing phosphoric acid and phosphotungstic acid, the mass percentage concentration of phosphoric acid is 10% to 80% and the mass percentage concentration of phosphotungstic acid is 0.0001% to 1.0%. When the silicates or aluminosilicates containing zeolites or molecular sieves are impregnated with the aqueous solution containing phosphoric acid and phosphotungstic acid, the mass ratio of zeolite or molecular sieve to the aqueous solution containing phosphoric acid and phosphotungstic acid is 1.0:1.0 to 100, the impregnation time is 2 to 48 hours, and the solid obtained after impregnation is calcined in a muffle furnace at 300℃ to 800℃ for 2 to 12 hours.

2. The method for preparing pyridine-2-carboxamide by catalytic cracking of 2-cyanopyridine distillation residue according to claim 1, characterized in that: The particle size of the catalyst is 50–300 mesh.

3. The method for preparing pyridine-2-carboxamide by catalytic cracking of 2-cyanopyridine distillation residue according to claim 1, characterized in that: Zeolites include 4A zeolite, mordenite, and / or HZSM-5 zeolite.

4. The method for preparing pyridine-2-carboxamide by catalytic cracking of 2-cyanopyridine distillation residue according to claim 1: the molecular sieve includes 3A potassium type, 4A sodium type, 5A calcium type, 10Z calcium type, 13Z sodium type and / or Y sodium type molecular sieve.

5. The method for preparing pyridine-2-carboxamide by catalytic cracking of 2-cyanopyridine distillation residue according to claim 1, characterized in that: After the content of phosphoric acid and phosphotungstic acid in the recovered impregnation solution is determined, an appropriate amount of phosphoric acid and phosphotungstic acid is added according to the requirements of the catalyst preparation process to meet the requirements for recycling.

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