111-46-6Relevant articles and documents
Synthesis of CNTs@POP-Salen Core-Shell Nanostructures for Catalytic Epoxides Hydration
Li, He,Zhong, Mingmei,Li, Chunzhi,Ren, Yiqi,Chen, Jian,Yang, Qihua
, p. 3952 - 3958 (2019)
Microporous polymers have been considered as promising heterogeneous catalysts for versatile chemical transformations. However, the mass diffusion barriers through the microporous network still remains a big hindrance. Herein, an efficient and versatile strategy for shortening the mass diffusion pathway through microporous polymer was reported by constructing a CNTs@POP-salen core-shell nanostructure. CNTs@POP-Co(salen) could efficiently catalyze the epoxide hydration reaction at H2O/epoxides ratio as low as 2, demonstrating the efficient cooperation of Co(salen) integrated in the polymer network. CNTs@POP-Co(salen) showed much higher activity than bulk polymer in propylene oxide (PO) hydration reaction (TOF: 3150 versus 1470 h?1) due to the shortened diffusion pathway, which was further confirmed by adsorption experiment using phenol as probe molecule. Our primary results demonstrated the advantages of core-shell nanostructures to improve the catalytic activity of microporous polymers by enhancing the mass diffusion during the catalytic process.
CO2atmosphere enables efficient catalytic hydration of ethylene oxide by ionic liquids/organic bases at low water/epoxide ratios
Ding, Tong,Gao, Guohua,Xia, Fei,Yuan, Huixia,Zha, Jinyin,Zhang, Dawei,Zhang, Jingshun
supporting information, p. 3386 - 3391 (2021/05/25)
The development of an efficient and low-cost strategy for the production of monoethylene glycol (MEG) through hydration of ethylene oxide (EO) at low H2O/EO molar ratios is an important industrial challenge. We have established that by using CO2as the reaction atmosphere, hydration of EO can be achieved at a low H2O/EO ratio of 1.5?:?1 along with high yields (88-94%) and selectivities (91-97%) of MEG catalyzed by binary catalysts of ionic liquids and organic bases. The results are significantly better than those of experiments conducted under an atmosphere of N2. Isotope labeling experiments revealed that CO2had altered the reaction pathway and participated in the reaction, in which cycloaddition of EO with CO2occurred first followed by the hydrolysis of ethylene carbonate (EC) to generate MEG and recover CO2. The ionic liquids and organic bases synergistically catalyzed the one-pot two-step reaction. DFT calculations confirmed that this route is more kinetically favorable compared to the pathway of direct epoxide hydration.
Nanotitania catalyzes the chemoselective hydration and alkoxylation of epoxides
Ballesteros–Soberanas, Jordi,Leyva–Pérez, Antonio,Martínez–Castelló, Aarón,Oliver–Meseguer, Judit,Tejeda–Serrano, María
, (2021/10/12)
Glycols and ethoxy– and propoxy–alcohols are fundamental chemicals in industry, with annual productions of millions of tons, still manufactured in many cases with corrosive and unrecoverable catalysts such as KOH, amines and BF3?OEt2. Here we show that commercially available, inexpensive, non–toxic, solid and recyclable nanotitania catalyzes the hydration and alkoxylation of epoxides, with water and primary and secondary alcohols but not with phenols, carboxylic acids and tertiary alcohols. In this way, the chemoselective synthesis of different glycols and 1,4–dioxanones, and the implementation of nanotitania for the production in–flow of glycols and alkoxylated alcohols, has been achieved. Mechanistic studies support the key role of vacancies in the nano–oxide catalyst.
Catalysis, kinetic and mechanistical studies for the transformation of ethylene glycol by alumina and silica gel under autogenous pressure and solvent-free conditions
Rohand, Taoufik,Tanemura, Kiyoshi
, p. 387 - 394 (2021/06/25)
A kinetic and mechanistical studies of the new pathway for competitive transformation of ethylene glycol by alumina and silica gel have been described. Commercial alumina (Al com), synthetic alumina (Al syn), commercial silica gel (Si com) and synthetic silica gel (Si syn) were used for the transformation of ethylene glycol to a mixture of diethylene glycol, 1,4-dioxane and 2-methyl-1,3-dioxolane via acetaldehyde by heating at 150 °C under autogenous pressure without solvent. The results show that the yield of these three products strongly depends on the nature of the used catalyst and the reaction time.
Chromium-Catalyzed Production of Diols From Olefins
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Paragraph 0111, (2021/03/19)
Processes for converting an olefin reactant into a diol compound are disclosed, and these processes include the steps of contacting the olefin reactant and a supported chromium catalyst comprising chromium in a hexavalent oxidation state to reduce at least a portion of the supported chromium catalyst to form a reduced chromium catalyst, and hydrolyzing the reduced chromium catalyst to form a reaction product comprising the diol compound. While being contacted, the olefin reactant and the supported chromium catalyst can be irradiated with a light beam at a wavelength in the UV-visible spectrum. Optionally, these processes can further comprise a step of calcining at least a portion of the reduced chromium catalyst to regenerate the supported chromium catalyst.
AEROBIC ELECTROCATALYTIC OXIDATION OF HYDROCARBONS
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Paragraph 0074, (2022/01/04)
This invention is directed to a method of oxygenating hydrocarbons with molecular oxygen, O2, as oxidant under electrochemical reducing conditions, using polyoxometalate compounds containing copper such as Q10 [Gu4(H2O)2(B-α-PW9O)2] or Q12{ [Cu(H2O)]3[(A-α- PW9O34)2(NO3)-] } or solvates thereof as catalysts, wherein Q are each independently selected from alkali metal cations, alkaline earth metal cations, transition metal cations, NH4+,H+ or any combination thereof.
CATALYTIC CONVERSION OF CARBON DIOXIDE TO METHANOL
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Page/Page column 23; 24, (2019/10/29)
The present disclosure relates to a new catalytic process for the production of methanol from carbon dioxide, comprising: (1) the conversion of carbon dioxide and hydrogen to formic acid or formate salts; (2) converting the formic acid or formate salts to diformate esters of diols; (3) hydrogenating the diformate esters to methanol and diols. The diols produced from the hydrogenation reaction can be recovered and re-used to prepare the diformate esters.
Synthesis of dioxolanes and oxazolidines by silica gel catalysis
Rohand, Taoufik,Savary, Jér?me,Markó, István E.
, p. 1429 - 1436 (2018/06/25)
Abstract: Ethylene glycol condensed with carbonyl compounds in the presence of silica gel or alumina, without solvent and under pressure, affords 1,3-dioxolanes. 2-Amino-2-methylpropanol also condensed with carbonyl compounds in the presence of silica gel or an acid-activated clay, without solvent and under pressure, produces oxazolidines. To explain these results, we propose that the glycol and the aminopropanol react with Br?nsted (H+) and Lewis acid sites (Si and Al) located on the surface of the catalysts, leading to the products via various ionic intermediates.
Self-assembled orthoester cryptands: Orthoester scope, post-functionalization, kinetic locking and tunable degradation kinetics
L?w, Henrik,Mena-Osteritz, Elena,Von Delius, Max
, p. 4785 - 4793 (2018/06/07)
Dynamic adaptability and biodegradability are key features of functional, 21st century host-guest systems. We have recently discovered a class of tripodal supramolecular hosts, in which two orthoesters act as constitutionally dynamic bridgeheads. Having previously demonstrated the adaptive nature of these hosts, we now report the synthesis and characterization-including eight solid state structures-of a diverse set of orthoester cages, which provides evidence for the broad scope of this new host class. With the same set of compounds, we demonstrated that the rates of orthoester exchange and hydrolysis can be tuned over a remarkably wide range, from rapid hydrolysis at pH 8 to nearly inert at pH 1, and that the Taft parameter of the orthoester substituent allows an adequate prediction of the reaction kinetics. Moreover, the synthesis of an alkyne-capped cryptand enabled the post-functionalization of orthoester cryptands by Sonogashira and CuAAC "click" reactions. The methylation of the resulting triazole furnished a cryptate that was kinetically inert towards orthoester exchange and hydrolysis at pH > 1, which is equivalent to the "turnoff" of constitutionally dynamic imines by means of reduction. These findings indicate that orthoester cages may be more broadly useful than anticipated, e.g. as drug delivery agents with precisely tunable biodegradability or, thanks to the kinetic locking strategy, as ion sensors.
Ketalization of ketones to 1,3-dioxolanes and concurring self-aldolization catalyzed by an amorphous, hydrophilic SiO2-SO3H catalyst under microwave irradiation
Barbosa, Sandro L.,Ottone, Myrlene,De Almeida, Mainara T.,Lage, Guilherme L.C.,Almeida, Melina A.R.,Nelson, David Lee,Dos Santos, Wallans T.P.,Clososki, Giuliano C.,Lopes, Norberto P.,Klein, Stanlei I.,Zanatta, Lucas D.
, p. 1663 - 1671 (2018/06/29)
The amorphous, mesoporous SiO2-SO3H catalyst with a surface area of 115 m2 g-1 and 1.32 mmol H+ per g was very efficient for the protonation of ketones on a 10percent (m/m) basis, and the catalyst-bound intermediates can be trapped by polyalcohols to produce ketals in high yields or suffer aldol condensations within minutes under low-power microwave irradiation. The same catalyst can easily reverse the ketalization reaction. Printed in Brazil-
