25188-98-1Relevant academic research and scientific papers
Gold-based catalyst for oxidative esterification of aldehydes to carboxylic acid esters
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Page/Page column 15, (2021/02/03)
The present invention relates to novel catalysts for oxidative esterification, by means of which, for example, (meth)acrolein can be converted to methyl (meth)acrylate. The catalysts of the invention are especially notable for high mechanical and chemical stability even over very long periods. This especially relates to an improvement in the catalyst service life, activity and selectivity over prior art catalysts which lose activity and/or selectivity relatively quickly in continuous operation in media having even a small water content.
The effect of the bimetallic Pd-Pb structures on direct oxidative esterification of methacrolein with methanol
Diao, Yanyan,Qi, Miao,Song, Yuting,Wang, Ling,Wu, Xiangying
, (2021/06/28)
Supported palladium and palladium alloy were proved to be active catalysts for the oxidative esterification reaction of methacrolein with methonal to methyl methacrylate. Here we synthesized two types of structurally supported palladium alloy catalysts with ordered or disordered Pd3Pb intermetallic crystals by impregnation-reduction method as well as high temperature heat treatment. Importantly, the catalyst with disordered Pd3Pb crystals had 89% conversion for methylacrolein and 79% selectivity for methyl methacrylate, showing obvious higher activity than the catalyst with ordered Pd3Pb crystals. The morphology, metal arrangement and electron effect of the catalyst were analyzed by XRD, TEM and XPS. It was confirmed that more active sites and strong electron transfer between metals were the reasons for the excellent performance of the disordered catalyst. This study provides theoretical guidance for the further study of Pd-based catalysts for the oxidative esterification of methacrolein to methyl methacrylate.
Esterification or Thioesterification of Carboxylic Acids with Alcohols or Thiols Using Amphipathic Monolith-SO3H Resin
Ichihara, Shuta,Ishida, Moeka,Ito, Ryo,Kato, Ayumu,Monguchi, Yasunari,Nakamura, Shinji,Park, Kwihwan,Sajiki, Hironao,Takada, Hitoshi,Wakayama, Fumika,Yamada, Tsuyoshi,Yamada, Yutaro
, p. 2702 - 2710 (2022/01/19)
We have developed a method for the esterification of carboxylic acids with alcohols using amphipathic, monolithic-resin bearing sulfonic acid moieties as cation exchange functions (monolith-SO3H). Monolith-SO3H efficiently catalyzed the esterification of aromatic and aliphatic carboxylic acids with various primary and secondary alcohols (1.55.0 equiv) in toluene at 6080 °C without the need to remove water generated during the reaction. The amphipathic property of monolith-SO3H facilitates dehydration due to its capacity for water absorption. This reaction was also applicable to thioesterification, wherein the corresponding thioesters were obtained in excellent yield using only 2.0 equiv of thiol in toluene, although heating at 120 °C was required. Moreover, monolith-SO3H was separable from the reaction mixtures by simple filtration and reused for at least five runs without decreasing the catalytic activity.
A CATALYST AND A PROCESS FOR THE PRODUCTION OF ETHYLENICALLY UNSATURATED CARBOXYLIC ACIDS OR ESTERS
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Page/Page column 40, (2021/02/05)
The invention discloses a catalyst comprising a silica support, a modifier metal and a catalytic alkali metal. The silica support has a multimodal pore size distribution comprising a mesoporous pore size distribution having an average pore size in the range 2 to 50 nm and a pore volume of said mesopores of at least 0.1 cm3/g, and a macroporous pore size distribution having an average pore size of more than 50 nm and a pore volume of said macropores of at least 0.1 cm3/g. The level of catalytic alkali metal on the silica support is at least 2 mol%. The modifier metal is selected from Mg, B, Al, Ti, Zr and Hf. The invention also discloses a method of producing the catalyst, a method of producing an ethylenically unsaturated carboxylic acid or ester in the presence of the catalyst, and a process for preparing an ethylenically unsaturated acid or ester in the presence of the catalyst.
Multicatalytic Transformation of (Meth)acrylic Acids: a One-Pot Approach to Biobased Poly(meth)acrylates
Fouilloux, Hugo,Placet, Vincent,Qiang, Wei,Robert, Carine,Thomas, Christophe M.
supporting information, p. 19374 - 19382 (2021/07/21)
Shifting from petrochemical feedstocks to renewable resources can address some of the environmental issues associated with petrochemical extraction and make plastics production sustainable. Therefore, there is a growing interest in selective methods for transforming abundant renewable feedstocks into monomers suitable for polymer production. Reported herein are one-pot catalytic systems, that are active, productive, and selective under mild conditions for the synthesis of copolymers from renewable materials. Each system allows for anhydride formation, alcohol acylation and/or acid esterification, as well as polymerization of the formed (meth)acrylates, providing direct access to a new library of unique poly(meth)acrylates.
The effect of viscosity on the coupling and hydrogen-abstraction reaction between transient and persistent radicals
Li, Xiaopei,Kato, Tatsuhisa,Nakamura, Yasuyuki,Yamago, Shigeru
, p. 966 - 972 (2021/04/29)
The effect of viscosity on the radical termination reaction between a transient radical and a persistent radical undergoing a coupling reaction (Coup) or hydrogen abstraction (Abst) was examined. In a non-viscous solvent, such as benzene (bulk viscosity bulk 99% Coup/Abst selectivity, but Coup/Abst decreased as the viscosity increased (89/11 in PEG400 at 25 °C [bulk = 84 mPa s]). While bulk viscosity is a good parameter to predict the Coup/Abst selectivity in each solvent, microviscosity is the more general parameter. Poly(methyl methacrylate) (PMMA)-end radicals had a more significant viscosity effect than polystyrene (PSt)-end radicals, and the Coup/Abst ratio of the former dropped to 50/50 in highly viscous media (bulk = 3980 mPa s), while the latter maintained high Coup/ Abst selectivity (84/16). These results, together with the low thermal stability of dormant PMMA-TEMPO species compared with that of PSt-TEMPO species, are attributed to the limitation of the nitroxide-mediated radical polymerization of MMA. While both organotellurium and bromine compounds were used as precursors of radicals, the former was superior to the latter for the clean generation of radical species.
HETEROGENEOUS CATALYST
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Page/Page column 5-7, (2020/01/24)
A heterogeneous catalyst comprising a support and gold, wherein: (i) said support comprises alumina, (ii) said catalyst comprises from 0.1 to 5 wt% of gold, (iii) at least 90 wt% of the gold is in the outer 60% of catalyst volume, and (iv) particles of the catalyst have an average diameter from 200 microns to 30 mm; wherein weight percentages are based on weight of the catalyst. The catalyst of this invention is used in a process for producing methyl methacrylate (MMA) which comprises treating methacrolein with methanol in an oxidative esterification reactor.
Method for carrying out a heterogeneously catalysed reaction
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Page/Page column 8-10, (2020/04/09)
A process for performing a heterogeneously catalysed reaction in a three-phase reactor, where there is at least one liquid phase, at least one gaseous phase and at least one solid phase in the reactor and the reactor has at least two zones, with the reaction mixture being conveyed downward in zone 1, the reaction mixture being conveyed upward in zone 2, zones 1 and 2 being separated from one another by a dividing wall, and in that the ratio between the average catalyst concentrations in zone 2 and in zone 1 is greater than 2.
Second-Generation meta-Phenolsulfonic Acid-Formaldehyde Resin as a Catalyst for Continuous-Flow Esterification
Hu, Hao,Ota, Hajime,Baek, Heeyoel,Shinohara, Kenta,Mase, Toshiaki,Uozumi, Yasuhiro,Yamada, Yoichi M. A.
supporting information, p. 160 - 163 (2020/01/02)
A second-generation m-phenolsulfonic acid-formaldehyde resin (PAFR II) catalyst was prepared by condensation polymerization of sodium m-phenolsulfonate and paraformaldehyde in an aqueous H2SO4 solution. This reusable, robust acid resin catalyst was improved in both catalytic activity and stability, maintaining the characteristics of the previous generation catalyst (p-phenolsulfonic acid-formaldehyde resin). PAFR II was applied in the batchwise and continuous-flow direct esterification without water removal and provided higher product yields in continuous-flow esterification than any other commercial ion-exchanged acid catalyst tested.
Synthesis method for acrylate with low polymerization inhibitor content
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Paragraph 0014-0021, (2020/05/01)
The invention discloses a synthesis method for acrylate with a low polymerization inhibitor content. The method comprises the following steps: in the presence of at least one polymerization inhibitor,directly esterifying acrylic acid or methacrylic acid and corresponding alcohol serving as raw materials under the action of an acidic catalyst to synthesize corresponding acrylate or methacrylate, and introducing air into a reactor in the reaction process to take water generated by the reaction out of the reactor; after reacting for a period of time, filtering an esterification reaction solutionto remove the catalyst, and carrying out alkali washing and water washing to obtain a product acrylate or methacrylate, wherein the polymerization inhibitor is a compound polymerization inhibitor, and the compound polymerization inhibitor comprises a cobaloxime boron fluoride complex and a phenolic compound. By adopting the compound polymerization inhibitor, the usage amount of the polymerizationinhibitor can be reduced to 5-20 ppm, the oxygen content in the reactor is not required, the method is suitable for industrial production and application, the requirements of customers on acrylate products with low polymerization inhibitor content can be met, and a subsequent step of removing the polymerization inhibitor is omitted.
