311 results about "Methacrolein" patented technology

The invention relates to a method for hydrogenation preparing isobutyl acohol from methacrolein, which comprises selecting a supported metal catalyst, and hydrogenating methacrolein obtained by oxidating isobutene under gentle conditions. The invention proposes a novel isobutyl acohol synthesis process, i.e., a process of hydrogenation preparing isobutyl acohol from methacrolein which is obtained by air-oxidating low-utilization C4 material isobutene. The methacrolein conversion rate is larger than 97.8%, the total selectivity of isobutyl acohol is larger than 95.9%, the performance of the catalyst is stable even the reaction lasts more than 1200 hours. The invention has the advantages of high activity and high selectivity of catalyst, good stability of catalyst, cheap material isobutene, low productin cost of isobutene, environment-protecting process, and suitability of industrialisation production.

The invention relates to a method for hydrogenation preparing isobutyraldehyde and isobutyl acohol from methacrolein. The method comprises using a supported metal catalyst, and hydrogenating methacrolein obtained by oxidating isobutene under gentle conditions. The invention provides a novel synthesis process for hydrogenation preparing isobutyraldehyde and isobutyl acohol from methacrolein which is obtained by air-oxidating low-utilization C4 material isobutene or tert-butanol. The methacrolein conversion rate is larger than 98%, the total selectivity of isobutyraldehyde and isobutyl acohol is larger than 95%, the performance of the catalyst is stable even the reaction lasts more than 1000 hours. The invention has the advantages of high activity and high selectivity of catalyst, good stability of catalyst, cheap material isobutene, low productin cost of isobutene, environment-protecting process, and suitability of industrialisation production. The process is flexible, can change the proportion of isobutyraldehyde and isobutyl acohol through adjusting the reaction process condition, thereby cogenerating isobutyraldehyde and isobutyl acohol, or only generating isobutyl acohol by cycling and hydrogenating isobutyraldehyde.

A heteropolyacid catalyst for oxidation of isobutyraldehyde, methacrolein or mixtures or combinations thereof to methacrylic acid is disclosed where the heteropolyacid catalyst includes at least molybdenum (Mo), phosphorus (P), vanadium (V), and a first component including bismuth (Bi) and/or boron (B). The heteropolyacid catalyst can also optionally include a second component including potassium (K), rubidium (Rb), cesium (Cs), and/or thallium (Tl) and optionally a third component including antimony (Sb), cerium (Ce), niobium (Nb), indium (In), iron (Fe), chromium (Cr), cobalt (Co), nickel (Ni), manganese (Mn), arsenic (As), silver (Ag), zinc (Zn), germanium (Ge), gallium (Ga), zirconium (Zr), magnesium (Mg), barium (Ba), lead (Pb), tin (Sn), titanium (Ti), aluminum (Al), silicon (Si), tantalum (Ta), tungsten (W), and/or lanthanum (La). The heteropolyacid catalyst can also include an ammonium-containing compound designed to increase a value of medium pores in the final heteropolyacid catalyst. A method for oxidizing isobutanal to methacrylic acid using the heteropolyacid catalyst is also disclosed.

A catalyst for producing methacrylic acid from methacrolein through vapor-phase catalytic oxidation which comprises as essential active ingredients molybdenum, vanadium, phosphorus, and copper, characterized by being one obtained using copper acetate as all or part of the copper material necessary for the catalyst preparation. By using the catalyst, methacrolein can be reacted at a high conversion and methacrylic acid can be produced with high selectivity. The catalyst is usable also in reactions under high-load conditions.

The object of the present invention is to provide a method for preparing a catalyst for producing methacrylic acid by subjecting methacrolein, isobutyl aldehyde or isobutyric acid to gas phase catalytic oxidation with high yield and high selectivity.

A method for preparing a catalyst for producing methacrylic acid by subjecting methacrolein, isobutyl aldehyde or isobutyric acid to gas phase catalytic oxidation, the method comprising: (a) a step of blending compounds each containing any one of Mo, V, P, Cu, Cs or NH₄ with water to prepare an aqueous solution or dispersion of the compounds (hereinafter referred to, both included, as a slurry); (b) a step of drying the slurry obtained in the step (a) to obtain a dried slurry; (c) a step of calcining the dried slurry obtained in..the step (b) to obtain a calcined body; (d) a step of filtering a mixture obtained by blending the calcined body obtained in the step (c) with water to separate an aqueous solution and water-insoluble matter; and (e) a step of drying the water-insoluble matter obtained in the step (d) to obtain a dried water-insoluble body.

The invention relates to an unsaturated aldehyde catalyst prepared by oxidizing olefin and a preparation method thereof, and mainly solves the problems of low reaction yield and selectivity of target products unsaturated aldehyde and unsaturated acid in the prior art. The catalyst takes at least one of SiO2 and Al2O3 as a carrier, and contains active ingredients shown as a formula Mo12BiaFebNicXdYeZfQqOx, wherein X is at least one of Mg, Co, Ca, Be, Cu, Zn, Pb and Mn; Y is at least one of Zr, Nb and Ti; Z is at least one of K, Rb, Na, Li, Cr, Tl and Cs; and Q is at least one of La, Ce, Sm andTh. Through the technical scheme, the catalyst and the preparation method thereof well solve the problems and can be used for the industrial production of acrolein or methacrolein prepared by oxidizing propylene or isobutylene.

The invention discloses a catalyst for preparing methylacrolein, a preparation method thereof as well as a method for preparing methylacrolein by catalyzing tert butyl alcohol or isobutene with the catalyst. The catalyst comprises a composite metal oxide which is expressed by the following general formula: (Mo12BiaFebCocCudCseVfNbiWjPbk): n carriers. The catalyst disclosed by the invention has the characteristics of high activity, high methylacrolein selectivity, high yield and the like. Finally, the conversion rate of the tert butyl alcohol or isobutene can be bigger than 95%, the methylacrolein selectivity can be bigger than 90%, and the single period yield of the methylacrolein can exceed 90%. The catalyst has the advantages of simple preparation technology and low production cost and is suitable for large-scale industrial application.

The invention discloses a heteropolyacid and oxide compound catalyst for preparing methacrylic acid through oxidation of methylacrolein. The preparation method of the catalyst comprises the following steps: mixing phosphomolybdic acid and metallic oxide (such as vanadium pentoxide, ferric oxide, cupric oxide, nickel oxide, manganese dioxide, cobaltous oxide, titanium dioxide and zinc oxide) in a liquid phase step by step so as to form relatively large amount of active sites on the surface of heteropolyanion; adding caesium to obtain the catalyst. The catalyst has high catalytic activity for preparing methacrylic acid through oxidation of methylacrolein and has a long catalyst service life.

The present invention relates to a catalytic continuous process for producing methyl methacrylate, said process comprising the step of reacting methacrolein with oxygen and methanol in the presence of a heterogeneous noble-metal-containing catalyst in an oxidative esterification reaction to give methyl methacrylate, characterized in that the stationary concentration of the starting material methacrolein is equal to or less than 12% by weight based on the total weight of the reaction mixture in the reactor, and the ratio F between the total liquid volume within the reactor expressed in litres divided by the total weight of catalyst in the reactor expressed in kilograms is equal to or less than 4.

Disclosed is an asymmetric total-synthesis method for chiral huperzine a. The method takes 1,4-dihydro-spiro (4,5) -8 -decanone as starting material to get benzoate through hydroxymethylation and the treatment of benzoyl chloride and K2CO3; the benzoate is reacted with hydrogen sulfate O-methyl iso urea to get quinazoline; after the ketal is eliminated, Mander reagent is used for methyl esterification reaction so as to obtain beta-keto ester. Chiral ammonia, such as cinchona alkaloid, is used to promote the tandem asymmetric Michael addition/aldol condensation reaction of beta-keto esters and methyl acrolein. The compound carboxylate of diastereoisomer is reacted with MsCl, triethylamine and DMAP to get transformed. Through TMSI and MeOH processing, the protective group is removed so as to obtain optically pure-chiral huperzine a.

The present invention relates to a process for preparing methyl methacrylate by a direct oxidative esterification of methacrolein with oxygen and methanol, which is conducted in the liquid phase at a pressure of 2 to 100 bar with a gold catalyst. According to the invention, the liquid phase is withdrawn continuously from the reactor and optionally enriched with oxygenous gas, the pH, after the withdrawal, is adjusted to a pH between 5 and 9 by means of addition of a basic solution and this liquid phase is conducted back into the reactor again to an extent of at least 50%.

A catalyst for oxidation of unsaturated and/or saturated aldehydes to unsaturated acids is disclosed where the catalyst includes at least molybdenum (Mo), phosphorus (P), vanadium (V), bismuth (Bi), and a first component selected from the group consisting of potassium (K), rubidium (Rb), cesium (Cs), thallium (Tl), or mixtures or combinations thereof, where the bismuth component was dissolved in an organic acid solution prior to adding the bismuth containing solution to a solution of the other components. Methods for making and using the catalysts are also disclosed.

Separation of methylacrolein in methyl methacrylate production is carried out by reacting to obtain mixed gas containing MAL, cooling and absorbing for MAL by 0~60 degrees C water, azeotropic rectifying with methanol as azeotropic agent, and separating MAL from mixed gas to obtain azeotropic mixture of MAL and methanol with water content lower 500pp. It is simple.

The invention relates to a selective hydrogenation catalyst, a preparation method and a catalyzing evaluation method for isobutyraldehyde by the selective hydrogenation catalyst. The selective hydrogenation catalyst comprises a carrier and active components, wherein the active components include a noble metal material and a non-noble metal material; the carrier is selected from one of fumed silica, precipitated silicon dioxide, aluminum oxide, carbon nitride and titanium dioxide; the noble metal material is noble metal, namely Ir (iridium); the non-noble metal material is selected from one of non-noble metals, namely Mo (molybdenum), W (tungsten), Ni (nickel), Co (cobalt), Sm (samarium), Ce (cerium) and Re (rhenium); the atom ratio of non-noble metal material to noble metal material is 0.8 to 5. The selective hydrogenation catalyst has the advantage that the methylacrolein can be selectively hydrogenated to generate the isobutyraldehyde in environment-friendly green solvent water under the milder reaction condition.

The present invention relates to an optimized process for the preparation of methacrolein. Methacrolein is used in chemical synthesis particularly as an intermediate for the preparation of methacrylic acid, methyl methacrylate or even active ingredients, fragrances or flavourings. In particular the present invention relates to the optimization of the process parameters by which, inter alia, a reduction of the content of harmful dimeric methacrolein in the end product may be achieved.

The invention relates to a catalyst for oxidizing isobutene of tert-butyl alcohol to prepare methy acraldehyde and a preparation method thereof, mainly solving the problems of low yield and low selectivity of the catalyst in the prior art. The catalyst comprises at least one selected from SiO2 or Al2O3 as a carrier and an active ingredient represented as Mo12BiaFebCocSbdEreXfYgZhOx, wherein, X isat least one selected from W, V, Ni, Cr, Mn, Nb or Re, Y is at least one selected from Sn, Sr, Zn, Ti or Zr, and Z is at least one selected from K, Rb, Na, Li, Tl or Cs. The invention can be applied in the industrial production of methy acraldehyde.

A process for the conversion of aldehydes to esters, specifically acrolein or methacrolein to methyl acrylate or methyl methacrylate, respectively. Essentially in the absence of water, an aldehyde is contacted with an oxidizing agent to form an intermediate and then the intermediate is contacted with a diol or an alcohol to form an ester or diester. Preferably, the oxidizing agent is also a chlorinating agent. Specifically, acrolein or methacrolein is contacted with an oxidizing/chlorinating agent, such as t-butyl hypochlorite, and the chlorinated compound is contacted with an alcohol, such as methanol, to form methyl acrylate or methyl methacrylate, respectively. Generally, the order of addition is for the oxidizing agent to be added to the aldehyde, specifically for t-butyl hypochlorite to be added to acrolein or methacrolein, and for the diol or alcohol to be added to the intermediate, specifically for the methanol to be added to the reaction product of acrolein or methacrolein and t-butyl hypochlorite. The process of the present invention can be carried out in the absence or in the presence of solvent. Generally, better methyl acrylate or methyl methacrylate yields are obtained at lower reaction temperatures.

The invention provides a preparation method of a catalyst used in reaction of preparing methylacrolein by selective oxidation of isobutene/tertiary butanol, wherein the catalyst is a composite oxide containing Mo, Bi, Fe, Co, K and Si. The preparation method comprises the steps of: stirring and mixing one or two of precursor compound silicon micro powder of Si and white carbon black with precursor compounds of other active components except for the Si to obtain mixed slurry, and then drying, forming and roasting the mixed slurry to obtain the catalyst. The catalyst has high activity and lower required reaction temperature when used in the reaction of preparing unsaturated aldehyde through selective oxidation of isobutene/tertiary butanol; better methylacrolein can be obtained, and the selectivity is high; and the reaction hot point is lower and the stability of the catalyst is good.

The present invention is preparation process of catalyst for oxidizing isoutene into methyl acraldehyde, and features that the catalyst prepared in new process and with new composition has isoutene converting rate up to 98.5 %, methyl acraldehyde selectivity up to 91.2 %, and methyl acraldehyde yield of 89.83 % in preparing methyl acraldehyde through oxidizing isoutene at 380 deg.c.