52 results about "Methacrolein" patented technology

The application discloses a high-activity and high-stability catalyst for synthesizing methacrylonitrile and a preparation method and application thereof, and has the technical scheme that (1) manganese dioxide powder is added into an acid solution and placed in an oven, and the manganese dioxide powder is pickled at 120-150 DEG C for 10-24h; the pickling solution is filtered, washed, dried and calcined to obtain a pickling-treated catalyst carrier; (2) a ruthenium precursor is added into a solvent and fully dissolved to obtain a ruthenium solution; the pickling-treated catalyst carrier is added into the ruthenium solution and loaded under ultrasonic, and then the solution is filtered, washed, dried and calcined to obtain a ruthenium monatomic catalyst. The method is simple, the reaction condition is mild, the production cost is low, raw materials are easy to obtain, the conversion rate of methacrolein is high, the yield of methacrylonitrile is high, and the stability is good.

A process and a production plant for producing methacrolein from formaldehyde and propionaldehyde in the presence of a homogeneous catalyst mixture which is based at least on an acid and a base can be used. A catalyst mixture commonly used for this synthesis has an organic acid and a secondary amine. The presence of the homogeneous catalyst mixture in the reaction mixture is an essential prerequisite for achieving a high yield. The process realizes better water management, thus making it possible not only to reduce the total catalyst amount required but also to reduce undesired catalyst byproducts more efficiently than before.

The invention discloses a supported resin catalyst and a preparation method and application thereof, and relates to the technical field of resin catalysts. The invention prepares a novel supported resin catalyst, and applies the supported resin catalyst to the synthesis of methyl methacrylate by reacting methacrolein with methanol. By adopting a single active component, palladium, the conversion rate of methacrolein can be increased to over 97%, and the selectivity of methyl methacrylate can be increased to over 98%. The amount of the active component, palladium, used is about 1.5% of the mass of the methacrolein.

The invention belongs to the technical field of catalysts, and discloses a nanorod-like Keggin type heteropolyacid catalyst and a preparation method and application thereof, the nanorod-like Keggin type heteropolyacid catalyst has a double rod-like structure, and the double rod-like structure is a rod-like structure with the length of 50-150 nm and a rod-like structure with the length of 3-10 [mu] m. The heteropolyacid catalyst has the characteristics of large specific surface area, double rodlike structure and the like, and the reaction performance of the catalyst for preparing methacrylic acid by oxidizing methylacrolein can be optimized.

The invention relates to the technical field of preparation of methyl methoxyacrylate, and discloses a high-yield preparation method of methyl methoxyacrylate, which comprises the following steps: S1, production preparation: preparing methylacrolein, methanol, a catalyst, an ultrafiltration membrane, a pervaporation membrane, a nanofiltration membrane and a gas chromatograph; s2, pretreatment: activating the catalyst in a muffle furnace; s3, reaction: putting the activated catalyst, methylacrolein and methanol into a reaction kettle for reaction, and observing in real time by using a gas chromatograph; and S4, separation and purification: carrying out preliminary filtration on the reaction mixed solution through an ultrafiltration membrane, and then separating methyl methoxyacrylate through a pervaporation membrane. According to the method, separation and purification are carried out in a manner of combining an ultrafiltration membrane, a pervaporation membrane and a nanofiltration membrane, so that the problem that the product is decomposed or the purity is insufficient due to the fact that a reduced pressure distillation separation method is often adopted in a traditional methyl methoxyacrylate preparation method is solved.

A process can be used for preparing methyl methacrylate by direct oxidative esterification of methacrolein. Methyl methacrylate is used in large amounts for preparing polymers and copolymers with other polymerizable compounds. In addition, methyl methacrylate is an important synthesis unit for a variety of specialty esters based on methacrylic acid (MAA) which can be prepared by transesterification with the appropriate alcohol. There is consequently a great interest in very simple, economic and environmentally friendly processes for preparing this starting material. A corresponding optimized workup of the reactor output from the oxidative esterification of methacrolein, through which unconverted methacrolein (MAL) can be recycled very efficiently, is useful. In addition, the process can be carried out in a manner which compared to known variants is markedly more energy- and water-saving.

This invention relates to a selective gold-based oxidation catalyst, its preparation method, and its application; the catalyst comprises components represented by general formula (1): Au-Sc a / Si b Ce c X d O e In formula (1), a is the molar ratio of Sc to Au, with a value of 0.1 to 1.0; b is the molar ratio of Si to Au, with a value of 100 to 500; c is the molar ratio of Ce to Au, with a value of 1.0 to 30.0; d is the molar ratio of X to Au, with a value of 0.1 to 2.0; e is the number of oxygen atoms required to satisfy the oxidation states of each element in the active component; X is selected from at least one of Li, Na, K, Rb, and Cs. The catalyst of the present invention is used for selective oxidation, with high yield of target product and high conversion rate of raw materials. For example, it has the characteristics of high conversion rate of methacrolein and high yield of methyl methacrylate in the synthesis of alkyl acrylates.

The invention belongs to the technical field of catalytic materials, and particularly discloses an ionic liquid catalyst for preparing methylacrolein and a preparation method of the ionic liquid catalyst. According to the preparation method, ionic liquid (protonated morpholine hydrochloride or 1-butyl-3-methylimidazole chloride salt) and metal chloride are subjected to a reaction, metal chelating ionic liquid is obtained, and the ionic liquid catalyst is obtained. The ionic liquid catalyst disclosed by the invention is simple in synthesis operation and mild in reaction condition, and has good industrial amplification potential; compared with the traditional supported or single metal salt catalyst, the catalyst provided by the invention has the advantages that the metal ion loss or agglomeration phenomenon is not easy to occur in the use process, the service life of the catalyst is effectively prolonged, and the problem that the existing catalyst is easy to inactivate is solved; the catalyst is adjustable in active center, high in selectivity and excellent in catalytic performance.

The catalyst for the oxidative esterification of methacrolein to methyl methacrylate comprises a support having an average diameter of at least 0.8 mm. The support is selected from oxides of silicon, carbides of silicon, metal oxides, and metal carbides. The catalyst further comprises nickel oxide and gold particles disposed on the support. The gold particles have an average diameter of less than 12 nm and a standard deviation of + / - 4 nm. A process for preparing methyl methacrylate from methacrolein and methanol using the catalyst is also disclosed.

The present application provides a method for preparing (meth) acrylonitrile, the method comprising: a catalytic reaction step of reacting (meth) acrolein with ammonia in a reactor containing a catalyst to produce a crude product comprising (meth) acrylonitrile, unreacted ammonia, unreacted (meth) acrolein, and one or more by-products; and a purification step: separating (methyl) acrylonitrile from the crude product. According to the method, synthesis of (methyl) acrylonitrile can be realized by using a low-cost catalyst through safe, environment-friendly and mild process steps, and effective recycling of materials and heat is realized while generation of toxic impurities is avoided.

A catalyst comprising noble metal particles and titanium-containing particles. The noble metal particles and titanium-containing particles are disposed on an outer surface of a support. At least 20% by weight of the total weight of noble metal particles are adjacent to at least one titanium-containing particle. The noble metal particles have an average diameter of less than 15 nm, and the catalyst has an average diameter of at least 200 microns. A method for preparing methyl methacrylate from methacrolein and methanol using the catalyst is also disclosed.

The invention provides a preparation method of 4-methylpyrazole, and belongs to the field of fine chemical engineering. Sulfuric acid and iodide are used as catalysts to promote ring closing of the generated hydrazone intermediate, so that the conversion process of preparing 4-methylpyrazole from 2-methylacrolein and hydrazine hydrate is catalyzed. The sulfuric acid is a sulfuric acid aqueous solution with the mass fraction of 30-80%, and the iodide is a reagent capable of generating an iodine elementary substance or the iodine elementary substance. Compared with a traditional preparation method, a room-temperature dropwise adding strategy is adopted, the condition in a reaction kettle can be effectively observed, meanwhile, the reaction is milder, the operation risk is reduced, the yield and purity of the product are improved, and the color number of the product is reduced. The preparation process is high in operability and suitable for industrial production.

The invention provides a methacrylic acid catalyst, the chemical general formula of which is PxMoyVzOw [-COOH] n, P, Mo and V are active components, and the molar ratio of x: y: z: w: n is (0.8-2.0): (10.0-12.0): (0.5-2.5): (30.0-50.0): (1.0-6.0). When the methacrylic acid catalyst is used for selectively oxidizing methylacrolein, the methylacrolein conversion rate and the methacrylic acid selectivity are high, and the stability is excellent. And the preparation method of the methacrylic acid catalyst is simple, convenient and low in cost.

The application relates to a method for co-producing methacrylate and methallyl alcohol, comprising the following steps: mixing methacrolein, a first catalyst and an aprotic nonpolar solvent to carry out a Chichibabin reaction to obtain a first reaction solution; the first catalyst comprises an aluminum alcoholate catalyst; mixing a fatty alcohol, a second catalyst and the first reaction solution to carry out an ester exchange reaction to prepare methacrylate and methallyl alcohol; the second catalyst comprises at least one of a titanate and an organotin. The method can co-produce methacrylate and methallyl alcohol in one pot, the yield is relatively high, by-products are relatively few, and the purity of the methacrylate and the methallyl alcohol is relatively high.

The present invention provides a supported catalyst for synthesizing methyl methacrylate. The catalyst includes a carrier and an active component arranged on the carrier. The carrier is a Ce-M-N composite oxide treated with glow discharge plasma. The active component is Au, M is selected from one or more of Al, Ni, Cu, and Zr, and N is selected from one or more of K, Ca, Ba, and Mg. The Au loading is 0.5-3.0 wt%. The supported catalyst for synthesizing methyl methacrylate and a preparation method thereof are provided. The Ce-M-N oxide composite is used as a carrier and is composited with M to reduce its oxygen vacancy formation energy, making it easier to form oxygen vacancies. The electrons and negatively charged high-energy particles in the glow discharge plasma are utilized to generate oxygen vacancies in CeO2. The oxygen vacancies are easily activated by oxygen adsorption, thereby facilitating the oxidative esterification reaction of methanol and methacrolein, thereby improving the activity of the catalyst.

The application provides a method for preparing lilial. The method is that lilial is synthesized from t-butylbenzene and alpha-methylacrolein under the catalysis of a Ti-K(Na) / F-Meso-SiO2 heterogeneous catalyst. The catalyst used in the application is modified by F element on the carrier, further enhancing the B acid acidity of the catalyst, and the doping of K and / or Na on the Ti metal effectively improves the catalytic activity of the Ti metal. The catalyst used in the application has both B acid and L acid sites, and the two acid active centers synergistically catalyze, so that the process conditions are mild, the reaction time is short, the catalyst is easy to recycle, and the problem of a large amount of waste acid and solid waste generated after the use of traditional catalysts is solved.

1. A process for the simultaneous production of methacrylic acid and methyl methacrylate, comprising: a) producing methacrolein from propionaldehyde and formaldehyde; b) dividing the methacrolein into a first methacrolein stream and a second methacrolein stream; c) producing methacrylic acid from water and the first methacrolein stream in an oxidation reaction; and d) producing methyl methacrylate from methanol and the second methacrolein stream in an oxidative esterification reaction.

A process for the simultaneous production of methacrylic acid and methyl methacrylate, the process comprising: a) producing methacrolein from propionaldehyde and formaldehyde; b) splitting the methacrolein into a first methacrolein stream and a second methacrolein stream; c) producing methacrylic acid from water and the first methacrolein stream in an oxidation reaction; and d) producing methyl methacrylate from methanol and the second methacrolein stream in an oxidative esterification reaction.

A process for preparing a catalyst for the oxidative esterification of methacrolein to methyl methacrylate includes providing a support selected from an oxide of silicon, a carbide of silicon, a metal oxide, and a metal carbide. Particles of at least one oxide of a metal are provided on the support. The support is contacted with a gold salt and heated at a temperature ranging from 50°C to 600°C for a time ranging from at least 0.1 hours to 48 hours to convert the gold salt into gold nanoparticles having an average diameter of less than 12 nm and a standard deviation of + / - 4 nm, with at least 75% by number of the gold nanoparticles located within 20 nm of the metal oxide particle.

A catalyst for the oxidative esterification of methacrolein to methyl methacrylate, the catalyst comprising a support having an average diameter of at least 0.8 mm. The support is selected from the group consisting of oxides of silicon, carbides of silicon, metal oxides, and metal carbides. The catalyst also includes nickel oxide and gold particles disposed on the support. The gold particles have an average diameter of less than 12 nm and a standard deviation of + / -4 nm. Also disclosed is a method for preparing methyl methacrylate from methylacrolein and methanol using the catalyst.

The application discloses a preparation method of a supported Ag metal catalyst and application thereof, and the preparation method comprises the following steps: after a molecular sieve is impregnated with an alkali solution and a silver source solution, the molecular sieve is dried and calcined to obtain the supported Ag metal catalyst. The application is matched with a continuous reactor-fixed bed, and the production efficiency of 2-methylpropenol is greatly improved. Under the condition that hydrogen is used as a reducing agent and without a solvent, the conversion rate of methacrolein on the Ag metal catalyst reaches 90%, the selectivity of 2-methylpropenol is 89%, and the catalyst can be stably operated for a relatively long time.

The application discloses a kind of for methanol and methyl methacrolein oxidation esterification catalyst and its preparation method and application, belong to catalytic synthesis technical field.The application first prepares silicon-titanium molecular sieve TS-1 carrier, then loads gold nanoparticles, and gold-based catalyst is prepared, TS-1 carrier can not only stabilize gold salt, Ti-O-Au bond can be formed between titanium species in TS-1 carrier and gold nanoparticles, improve the interaction between gold metal and carrier, more effectively limit the size of gold particle, form smaller size nano gold particle and good dispersity, improve the specific surface area of catalyst, to improve catalyst activity and stability.Mass concentration is 45-80% methanol and methyl methacrolein mixed solution and the obtained catalyst are mixed sufficiently, oxygen is input, and oxidation esterification reaction occurs under 70-160 DEG C, 0.5-2MPa, to prepare methyl methacrylate.The gold-based catalyst prepared by the application significantly improves the conversion rate of methyl methacrolein and the selectivity of methyl methacrylate.

The application discloses a catalyst for oxidative esterification and a preparation method and application thereof, and belongs to the technical field of catalytic synthesis. The application uses a composite oxide as a carrier, and gold particles are loaded on the oxide composite carrier by combining plasma reduction technology and an organic matter induction mode. The method improves the dispersity and uniformity of the gold nanoparticles, realizes trace coating of the carrier on the nanoparticles, constructs a new metal oxide interface structure, further promotes the adsorption and activation of oxygen, and thus the performance of the oxidative esterification reaction is improved. The catalyst shows excellent activity in methyl propyl aldehyde, ethylene glycol and 5-hydroxymethyl furfural oxidative esterification reactions.

A process for concurrently producing methacrylic acid and methyl methacrylate comprising: a) producing methacrolein from propionaldehyde and formaldehyde; b) splitting the methacrolein into a first methacrolein stream and a second methacrolein stream; c) producing methacrylic acid in an oxidative reaction from water and the first methacrolein stream; and d) producing methyl methacrylate in an oxidative esterification reaction from methanol and the second methacrolein stream.

There is provided a process for preparing an alkyl methacrylate, the process comprising reacting methacrolein with an alkyl alcohol in an oxidative esterification reaction (OER) system in the presence of at least one inhibitor, an oxygen-containing gas, and a noble metal-containing catalyst to produce an OER product stream, the OER product stream comprises alkyl methacrylate, alkyl isobutyrate in an amount in the range of 0.1 ppm to 5000 ppm based on the total weight of the OER product stream, and at least one Michael addition product in an amount in the range of 0.01 wt% to 5 wt% based on the total weight of the OER product stream. The OER product stream is fed to an alcohol recovery distillation column to provide an overhead stream comprising alkyl alcohol and methacrolein and a bottoms stream comprising alkyl methacrylate, alkyl isobutyrate, acetal and / or hemiacetal of methacrolein. The bottoms stream of the alcohol recovery distillation column is fed to an acetal hydrolysis reactor and a phase separator.

A catalyst for oxidative esterification of methacrolein to methyl methacrylate comprises a support having an average diameter of at least 0.8 mm. The support is selected from an oxide of silicon, a carbide of silicon, a metal oxide, and a metal carbide. The catalyst further comprises nickel oxide and gold particles disposed on the support. The gold particles and have an average diameter of less than 12 nm and a standard deviation of + / −4 nm. A method for preparing methyl methacrylate from methacrolein and methanol using the catalyst is also disclosed.

To provide a catalyst which is produced by a production method of the invention and can suppress variation of activity during use of the catalyst in a gas phase contact oxidation method, wherein, especially in a reaction for producing methacrylic acid from methacrolein as a raw material, the effect is remarkable and safe plant operation is enabled.SOLUTION: There is provided a catalyst which has, as catalyst active ingredients, molybdenum, copper, and vanadium, and in which water is used as a solvent, the catalyst having a maximum absorption wavelength in a wavelength range of 670 nm to 800 nm as measured by ultraviolet-visible spectroscopy (transmission system).SELECTED DRAWING: None

The invention relates to the technical field of preparation of methyl methacrylate, in particular to a hydrotalcite-based catalyst, preparation of the hydrotalcite-based catalyst and application of the hydrotalcite-based catalyst in production of methyl methacrylate. In the invention, the hydrotalcite-based catalyst comprises a carrier and an active center loaded on the carrier, the carrier is lanthanide series metal modified hydrotalcite (MgO-Al2O3-La2O3), and the catalyst is a catalyst. The active center is gold; wherein the loading capacity of the gold is 0.5-1 wt%. According to the preparation method, the gold particle catalyst with uniform particles and high activity can be obtained, the preparation process is simple, operation is convenient, the loading amount of active components is low, meanwhile, the catalyst has excellent activity and good stability, the preparation cost of the catalyst is low, the conversion rate of methylacrolein and the selectivity of MMA are high, and the catalyst is suitable for industrial production.

This invention provides a method for preparing a catalyst for the oxidation of isobutylene to methacrolein and its application. The preparation method includes the following steps: Step 1: Mixing a molybdenum-containing precursor solution I, a bismuth-containing precursor solution II, and a cobalt- and iron-containing precursor solution III to obtain solution V; Step 2: Adding a hydroxylated polycarboxylic acid to solution V and performing a crystallization reaction to obtain a catalyst precursor; Step 3: Calcining the catalyst precursor to obtain a catalyst for the oxidation of isobutylene to methacrolein; wherein the hydroxylated polycarboxylic acid is selected from one or more combinations of glycolic acid, lactic acid, citric acid, malic acid, and tartaric acid. This invention, through pretreatment with hydroxylated polycarboxylic acids, can block dispersed oxide lattice clusters, inhibit the formation of large particle structures, and fully expose the active defect sites of the catalyst, thereby improving catalytic activity.