25120-30-3Relevant academic research and scientific papers
Catalytic synthesis of methacrolein: Via the condensation of formaldehyde and propionaldehyde with l-proline
Yu, Jiayuan,Jensen, Anker Degn,Wang, Lei,Li, Chunshan,Zhang, Suojiang
, p. 4222 - 4230 (2020)
Methacrolein (MAL) is an important chemical for the manufacture of methyl methacrylate and a key monomer in many polymerization reactions. In this study, l-proline was investigated as the catalyst for the aldol condensation of formaldehyde and propionaldehyde to produce MAL. The catalytic activity of the reaction system was closely related to the competition between the main reaction synthesizing MAL and the side reaction producing 2-methyl-2-pentenal, which could be modified by adjusting the operating parameters. The influences of several operating conditions, including temperature, reaction time and water content, on the catalytic performance of the system were systematically studied via a series of single-factor experiments, and the optimized reaction conditions were obtained. The mechanistic investigation via ESI-MS indicated that the reaction pathway followed the Mannich route. Experimental and theoretical kinetic analyses of the l-proline-catalyzed aldol condensation reaction were performed, and the reaction orders of the reactants were obtained by regression. The results showed that l-proline was an efficient catalyst for the production of MAL via aldol condensation under mild conditions.
Performance and characterization of novel Re-Sb-O catalysts active for the selective oxidation of isobutylene to methacrolein
Liu, Haichao,Gaigneaux, Eric M.,Imoto, Hideo,Shido, Takafumi,Iwasawa, Yasuhiro
, p. 2033 - 2043 (2000)
The effects of the pretreatment conditions for Re-Sb-O compounds (SbOReO4·2H2O, Sb4Re2O13, and SbRe2O6) in the reaction atmosphere on these performance of the compounds as catalysts were investigated in the selective oxidation of isobutylene to methacrolein at 673 K. Each Re-Sb-O compound was characterized before and after the pretreatments and the catalytic reactions using XRD, XPS, SEM, and in situ Raman microscopy. SbRe2O6 exhibited the highest performance as a new promising catalyst. The compound underwent a progressive decomposition to Sb4Re2O13 and Re2O7 when pretreated or reacted at 673 K in the presence of oxygen. The decomposition was favored under more oxidative conditions and a close parallelism between the catalytic performance and the quantity of Re2O7 stabilized at the surface of the catalyst was observed. Conversely, the activities of pure Re2O7 and a new Sb4Re2O13 compound were very low when each of them was used as a catalyst independently. The results indicated that the reactivity of SbRe2O6 is likely due to the presence of Re2O7 at the surface, benefiting from a cooperation with Sb4Re2O13. The model also accounted for the performance of SbOReO4·2H2O. Regardless of the reaction atmosphere, SbOReO4·2H2O than Sb4Re2O13 and Re2O7, explaining a higher activity of SbOReO4·2H2O decomposed to Sb4Re2O13. However, the amount of Re2O7 stabilized at the surface was smaller than that for the case of SbRe2O6, which leads to lower performances of SbOReO4·2H2O than those of SbRe2O6.
Catalytic performances and stability of three Sb-Mo-O phases in the selective oxidation of isobutene to methacrolein
Gaigneaux,Dieterle,Ruiz,Mestl,Delmon
, p. 10542 - 10555 (1998)
We investigated the possible role of binary oxides associating Sb and Mo in the synergetic effects between physically mixed MoO3 and α-Sb2O4 in the selective oxidation of isobutene to methacrolein. The catalytic behavior of three Sb-Mo-O phases-Sb2MoO6 on one hand, a mixture of Sb2Mo10O31 and Sb4MO10O31 on the other hand - was investigated. The samples were characterized using X-ray diffraction (XRD), confocal laser Raman microscopy, specific area measurements, and scanning electron microscopy. Additional in situ high-temperature XRD was also performed. At similar conversions of isobutene, the selectivities to methacrolein for the Sb-Mo-O phases were always lower than those of mixtures of MoO3 with α-Sb2O4 with the same atomic compositions. A second result was that the three Sb-Mo-O phases were unstable in the conditions of reaction and tended to decompose to simple molybdenum and antimony oxides. An improvement of the catalytic performances of the Sb-Mo-O catalysts occurred in parallel to their decomposition. Some apparent cooperation effects were observed for mechanical mixtures of the Sb-Mo-O phases with MoO3 α-Sb2O4. These effects are actually related to the decomposition of the Sb-Mo-O phases and are due to the cooperation between MoO3. and α-Sb2O4 formed at their surface. The spontaneous decomposition of the Sb-Mo-O phases shows that these phases cannot form in operandi (during the catalytic reaction) starting from the simple oxides. Consequently, this shows that they cannot be the real most performant phases in the mixtures of MoO3 with α-Sb2O4 and hence that they cannot be at the origin of the synergism between the simple oxides.
Electronic activity relationship for methacrolein formation over 4th period transition metal phosphomolybdates
Kendell, Shane M.,Nguyen, Ngoc Ha,Brown, Trevor C.
, p. 61 - 70 (2013)
Phosphomolybdate compounds have been investigated for their structural characteristics and oxidation activity toward isobutane. The phosphomolybdates were synthesized from phosphomolybdic acid and the fourth period transition metal cations Cr3+, Mn2+, Fe3+, Fe 2+, Co2+, Ni2+ Cu2+, Cu+ and Zn2+. Two compounds were synthesized per transition metal: where (i) all the protons had been replaced by the particular transition metal, and (ii) only partial proton replacement leaving a single proton per phosphomolybdate. X-ray diffraction analysis has shown that a primitive cubic phase is apparent with some of the transition metal phosphomolybdates. Each solid was exposed to isobutane using the anaerobic low-pressure steady-state technique. Category 1 exponential-like distributions of methacrolein were observed with all the transition metal phosphomolybdates, except the lower oxidation state iron and copper salts, Fe1.5[PMo12O 40] and Cu3[PMo12O40] respectively. Activation energies ranged from 51.31 ± 0.27 kJ mol-1 (Cr[PMo12O40]) to over 200 kJ mol-1 (Zn 1.5[PMo12O40]). Phosphomolybdates with counter cations which are one or two electrons deficient from either a 3d 5 or 3d 10 configuration (in this case 3d 3, 3d 8 or 3d 9) had the lowest activation barriers for methacrolein formation. A computational investigation into HOMO-LUMO band gap energies agrees with the association. The presence of protons also enhances Category 1 product formation and may be attributed to migration of H+ through the bulk of the solid. Graphical Abstract: [Figure not available: see fulltext.]
IMPROVED SAFE METHOD FOR TANDEM C-4 OXIDATION TO METHACRYLIC ACID
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Page/Page column 14-17, (2021/10/11)
The present invention relates to an improved process for the production of methacrylates, in particular methacrylic acid and/or methyl methacrylate (MMA). Furthermore, the present invention relates to a process and specific embodiments of this process for the safe and efficient production of these products from C-4-based raw materials, in particular those based on isobutylene or tert-butanol as raw materials. With this novel process, it is possible to operate such processes for a longer period of time without any safety or cleaning related shutdowns. This makes it possible to carry out such processes as simple, economic and environmentally friendly as possible.
SYSTEMS AND METHODS FOR REGIOSELECTIVE CARBONYLATION OF 2,2-DISUBSTITUTED EPOXIDES FOR THE PRODUCTION OF ALPHA,ALPHA-DISUBSTITUTED BETA-LACTONES
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Paragraph 0082, (2021/01/29)
Provided are methods of producing carbonyl compounds (e.g., carbonyl containing compounds) and catalysts for producing carbonyl compounds. Also provided are methods of making polymers from carbonyl compounds and polymers formed from carbonyl compounds. A method may produce carbonyl compounds, such as, for example α,α-disubstituted carbonyl compounds (e.g., α,α-disubstituted β-lactones). The polymers may be produced from α,α-disubstituted β-lactones, which may be produced by a method described herein.
Supported Rb- or Cs-containing HPA catalysts for the selective oxidation of isobutane
Dumeignil, Franck,Katryniok, Benjamin,Paul, Sébastien,Zhang, Li
, (2021/10/29)
Silica-supported catalysts based on Keggin-type heteropolyacids (HPAs) containing rubidium or cesium as counter cations have been prepared by the impregnation method and evaluated in the selective oxidation of isobutane to methacrolein and methacrylic acid. The catalysts were characterized by various techniques such as XRD, N2 physisorption, TGA, Raman spectroscopy, H2-TPR, and NH3-TPD in order to study their thermal stability, structural, and textural properties, acidity and reducibility. It was evidenced that the reducibility of the Keggin type HPAs was improved by supporting the active phase on SiO2. A loading of 40 wt% was the optimum for the selective oxidation of isobutane (IBAN) to methacrylic acid (MAA). The selectivities to MAA and methacrolein (MAC) at given conversion were increased when Cs+ was used as counter cation compared to Rb+. The same trend was observed for mono- and di-vanado-substituted phosphomolybdic acid, whereby the performance followed the order: CsV1/SiO2 > RbV1/SiO2 > CsV2/SiO2 > RbV2/SiO2. The density of acid sites was correlated to the catalytic activity, which underlines the importance of the acid sites for alkane activation.
MMA preparation method with isobutene including saturated hydrocarbon
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Paragraph 0033-0035; 0048, (2020/08/26)
The present invention relates to a method for preparing methyl methacrylate, including the steps of: (1) separating isobutene containing saturated hydrocarbons(n-butane and iso-butane) from flow of C4 cuts including butadiene, n-butene and isobutene through a catalytic distillation process; (2) producing methacrolein from the thus separated isobutene through primary oxidation reaction; (3) producing methacrylic acid from the thus produced methacrolein through secondary oxidation reaction; and (4) carrying out esterification of the thus produced methacrylic acid with methanol. It is possible to minimize introduction of nitrogen by virtue of high heat capacity and to reduce the size of a reactor and generation of gas in the rear end, thereby saving investment and cost and providing high cost-efficiency.(AA) Naptha steam cracker C4 mixture(BB) Butadiene(CC) Extractive distillation(DD) 2-butene(EE) Reactive distillation(FF) Isobutene, nandamp;iso-butane(GG) Produce methyl methacrylate(HH) Methyl methacrylateCOPYRIGHT KIPO 2020
PROCESS FOR PRODUCING METHYL METHACRYLATE
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Paragraph 0181-0222, (2020/10/03)
The present invention relates to a method for producing methyl methacrylate. According to the present invention, provided is a method for producing methyl methacrylate, which is capable of securing the safety of a process, while improving the catalyst life and increasing the production amount of methyl methacrylate.
PROCESS FOR PRODUCING METHACRYLIC ACID OR METHACRYLIC ACID ESTERS
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Page/Page column 16-17, (2020/03/02)
The present invention relates to a process for producing methacrylic acid or methacrylic acid esters. The present invention is directed to a new process for the production of methacrylic acid or alkyl methacrylate starting from Acrolein, which is available from glycerol or propane.
