32 results about "Methacrylaldehyde" patented technology

A producing method of (meth)acrolein or (meth)acrylic acid where by use of a multi-tubular reactor that has a plurality of reaction tubes filled with a catalyst, catalytic gas phase oxidation of propylene, propane, isobutylene or (meth)acrolein is carried out in the presence of a composite oxide catalyst by use of molecular oxygen or a gas containing molecular oxygen, in which method (meth)acrolein or (meth)acrylic acid can be obtained stably in high yield for a long period of time without allowing the activity of the catalyst to decrease locally (disproportionately) and extremely. A temperature difference between a temperature of a heat medium at the beginning of operation and a peak temperature of the catalyst is set in a range of 20 to 80° C., and during operations a change of the peak temperature T of the catalyst in a tube axis direction is maintained in a definite range.

The invention provides a preparation method of zolpidem. The method comprises the following steps: malononitrile and 2-methacrolein which are used as raw materials undergo a 1,4-addition reaction to prepare 2-methyl-4,4-dicyano-n-butyraldehyde, the 2-methyl-4,4-dicyano-n-butyraldehyde and N,N-dimethyl-4-p-methylphenyl-4-oxo-3-amino-n-butyramide undergo a two-stage dehydration condensation reaction, and the obtained reaction product and an acid binding agent undergo an elimination agent to prepare the zolpidem. The method of the invention has the advantages of cheap and easily available raw materials, short process flow, mild reaction conditions, simplicity in operation, low cost, low amount of three wastes, greenness, environmental protection, good selectivity, high yield and high purity of the product, and facilitation of industrial production of the zolpidem.

Disclosed are a Mo—Bi—Nb—Te based composite metal oxide; and a process for producing (meth)acrylic acid from at least one reaction material selected from the group consisting of propylene, propane, isobutylene, t-butyl alcohol and methyl-t-butyl ether, wherein the Mo—Bi—Nb—Te based composite metal oxide is used as a catalyst. Also, disclosed is a process for producing (meth)acrylic acid comprising a first step of producing (meth)acrolein as a main product from at least one reaction material selected from the group consisting of propylene, propane, isobutylene, t-butyl alcohol and methyl-t-butyl ether, and a second step of producing (meth)acrylic acid from the (meth)acrolein, wherein yield of (meth)acrylic acid in the product of the first step is 20 mole % or higher.

The invention discloses a catalyst for producing methyl methacrylate by one-step oxidative esterification method and its preparation method and application. The catalyst uses materials containing electron-rich oxides as a composite carrier, metal palladium as an active The metal is the co-active component, and the surfactant is used as the co-agent. Its general chemical formula can be expressed as: X a PD b Y c / M d ‑N, where Pd is palladium, X is a surfactant, Y is one of the rare earth elements scandium, yttrium, lanthanum or cerium, M is an electron-rich oxide, and N is a carrier. The catalyst can be applied to the reaction of methyl methacrylate (MMA) produced by one-step production of methyl methacrylate (MMA) through oxidation of methacrolein and esterification with methanol. The catalyst overcomes some shortcomings of the existing oxidative esterification catalysts by forming a special electron-donating structure between the active component, the carrier and the surfactant, and is applied to the reaction of one-step oxidative esterification to produce MMA in addition to having conversion In addition to the advantages of high yield and good selectivity, it also has the characteristics of simple preparation process and mild reaction conditions.

The subject matter of the present invention is a process for direct synthesis of (meth)acrolein from a reactive mixture comprising at least one compound chosen from ethers, acetals or hemiacetals derived from linear alcohols comprising from 1 to 3 carbon atoms. Examples of compounds are dimethyl ether, diethyl ether, methyl ethyl ether, dimethoxymethane, diethoxymethane, dipropoxymethane, 1,1-dimethoxyethane or 1,1-diethoxyethane. The process of the invention comprises two successive phases: oxidation then aldol condensation, which can be carried out in the presence of a solid oxidation catalyst chosen from molybdenum-based catalysts and optionally of an aldol condensation catalyst. These two phases are carried out in a reaction system comprising a single reactor or optionally two reactors in cascade.

The invention discloses a catalyst for selectively oxidizing methacrylaldehyde to prepare methacrylic acid and preparation and application methods thereof. The catalyst for selectively oxidizing the methacrylaldehyde to prepare the methacrylic acid is composed of PaMobVcXxYyZz1HhOg1-Zz2Og2, wherein X is a combination of at least two from sodium, potassium, rubidium and cesium, Y is a mixture of one or at least two from calcium, magnesium, chromium, manganese, iron, cobalt, copper, nickel, zinc, aluminum, silicon, germanium, antimony, bismuth, lanthanum or cerium, and Z comprises titanium and / or zirconium. Compared with traditional phosphovanadomolybdate catalysts. The catalyst for selectively oxidizing the methacrylaldehyde to prepare the methacrylic acid can be higher in activity when applied to selectively oxidizing the methacrylaldehyde to prepare the methacrylic acid, and during the catalytic process, when the methacrylaldehyde converting rate is 90%, and the selectivity to the methacrylic acid can reach up to 93%, so that the catalyst for selectively oxidizing the methacrylaldehyde to prepare the methacrylic acid can meet the demands of practical industrial production.