2234-16-4Relevant articles and documents
Oxidative Cleavage of Alkenes by O2with a Non-Heme Manganese Catalyst
Bennett, Elliot L.,Brookfield, Adam,Guan, Renpeng,Huang, Zhiliang,Mcinnes, Eric J. L.,Robertson, Craig M.,Shanmugam, Muralidharan,Xiao, Jianliang
supporting information, p. 10005 - 10013 (2021/07/19)
The oxidative cleavage of C═C double bonds with molecular oxygen to produce carbonyl compounds is an important transformation in chemical and pharmaceutical synthesis. In nature, enzymes containing the first-row transition metals, particularly heme and non-heme iron-dependent enzymes, readily activate O2 and oxidatively cleave C═C bonds with exquisite precision under ambient conditions. The reaction remains challenging for synthetic chemists, however. There are only a small number of known synthetic metal catalysts that allow for the oxidative cleavage of alkenes at an atmospheric pressure of O2, with very few known to catalyze the cleavage of nonactivated alkenes. In this work, we describe a light-driven, Mn-catalyzed protocol for the selective oxidation of alkenes to carbonyls under 1 atm of O2. For the first time, aromatic as well as various nonactivated aliphatic alkenes could be oxidized to afford ketones and aldehydes under clean, mild conditions with a first row, biorelevant metal catalyst. Moreover, the protocol shows a very good functional group tolerance. Mechanistic investigation suggests that Mn-oxo species, including an asymmetric, mixed-valent bis(μ-oxo)-Mn(III,IV) complex, are involved in the oxidation, and the solvent methanol participates in O2 activation that leads to the formation of the oxo species.
Promoting charge separation in donor-acceptor conjugated microporous polymers: Via cyanation for the photocatalytic reductive dehalogenation of chlorides
Deng, Jiyong,Fang, Zhengjun,Lan, Donghui,Liao, Yunfeng,Liu, Qingquan,Zhang, Weijie,Zhou, Xiang
, p. 7151 - 7159 (2021/11/17)
Conjugated microporous polymers (CMPs) have emerged as promising heterogeneous photocatalysts for organic transformations owing to their structural designability and functional versatility. However, limited by the insufficient separation of the photo-generated excitons, their photocatalytic efficiency falls far short of expectations. Herein, we demonstrate a cyanation strategy to promote charge carrier separation in CMPs by selectively incorporating carbazole and cyano groups as electron-donating and electron-withdrawing units, respectively. The resulting CMPs feature π-extended donor (D)-acceptor (A) conjugation structures endowing them with distinct semiconducting properties, in which the efficient charge separation and transfer and wide visible-light absorption are facilitated. Compared to the cyano-free counterpart, the cyano-functionalized CMPs showed superior photocatalytic efficiency as exemplified by photocatalytic reductive dehalogenation of chlorides. More prominently, full recyclability of the designed CMPs as well as catalytic activity for at least ten runs without the loss of catalytic performance in photocatalytic reductive dehalogenation of chlorides demonstrated their robustness and sustainability. This journal is
The dehydrogenative oxidation of aryl methanols using an oxygen bridged [Cu-O-Se] bimetallic catalyst
Choudhury, Prabhupada,Behera, Pradyota Kumar,Bisoyi, Tanmayee,Sahu, Santosh Kumar,Sahu, Rashmi Ranjan,Prusty, Smruti Ranjita,Stitgen, Abigail,Scanlon, Joseph,Kar, Manoranjan,Rout, Laxmidhar
supporting information, p. 5775 - 5779 (2021/04/12)
Herein, we report a new protocol for the dehydrogenative oxidation of aryl methanols using the cheap and commercially available catalyst CuSeO3·2H2O. Oxygen-bridged [Cu-O-Se] bimetallic catalysts are not only less expensive than other catalysts used for the dehydrogenative oxidation of aryl alcohols, but they are also effective under mild conditions and at low concentrations. The title reaction proceeds with a variety of aromatic and heteroaromatic methanol examples, obtaining the corresponding carbonyls in high yields. This is the first example using an oxygen-bridged copper-based bimetallic catalyst [Cu-O-Se] for dehydrogenative benzylic oxidation. Computational DFT studies reveal simultaneous H-transfer and Cu-O bond breaking, with a transition-state barrier height of 29.3 kcal mol?1
Clean production method for improving reaction yield of 2, 4-dichloroacetophenone
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Paragraph 0011-0022, (2020/04/06)
The invention relates to a clean production method for improving the reaction yield of 2, 4-dichloroacetophenone, which comprises the following steps: S1, separating and extracting m-dichlorobenzene by using chlorinated aromatic hydrocarbon waste; S2, preparing crude 2, 4-dichloroacetophenone; and S3, separating and purifying the crude 2, 4-dichloroacetophenone to obtain a dichloroacetophenone product. The method has the advantages that the optimal reaction conditions are found through the influence of the feeding ratio, the reaction temperature, the reaction time, different Lewis acids and the AlCl3 dosage on the product yield, the purity and the yield of the product are guaranteed, the purity of the product can reach 99.5% or above, and the yield of the product can reach 65% or above.
MnO2as a terminal oxidant in Wacker oxidation of homoallyl alcohols and terminal olefins
Fernandes, Rodney A.,Ramakrishna, Gujjula V.,Bethi, Venkati
, p. 6115 - 6125 (2020/10/27)
Efficient and mild reaction conditions for Wacker-type oxidation of terminal olefins of less explored homoallyl alcohols to β-hydroxy-methyl ketones have been developed by using a Pd(ii) catalyst and MnO2 as a co-oxidant. The method involves mild reaction conditions and shows good functional group compatibility along with high regio- and chemoselectivity. While our earlier system of PdCl2/CrO3/HCl produced α,β-unsaturated ketones from homoallyl alcohols, the present method provided orthogonally the β-hydroxy-methyl ketones. No overoxidation or elimination of benzylic and/or β-hydroxy groups was observed. The method could be extended to the oxidation of simple terminal olefins as well, to methyl ketones, displaying its versatility. An application to the regioselective synthesis of gingerol is demonstrated.
Synthesis method of 2, 4-dichloroacetophenone
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Paragraph 0011-0014, (2020/05/30)
The invention discloses a synthesis method of 2, 4-dichloroacetophenone. The method comprises the following steps: carrying out electrophilic substitution reaction on m-dichlorobenzene and acetyl chloride in an ionic liquid (Bmin)Cl-FeCl3 medium to synthesize the 2, 4-dichloroacetophenone; adding m-dichlorobenzene and acetyl chloride into the (Bmin)Cl-FeCl3 ionic liquid according to a molar ratioof 1:(1.1-1.2), carrying out a stirring reaction for 4h at a temperature of 40-60 DEG C, extracting 2, 4-dichloroacetophenone with cyclohexane, and carrying out reduced pressure distillation to removethe solvent so as to obtain 2, 4-dichloroacetophenone. The weight ratio of the feeding amount of the ionic liquid (Bmim)Cl-FeCl3 to the total feeding amount of m-dichlorobenzene and acetyl chloride is 1:(1-0.8). The method has the advantages that the use of anhydrous aluminum chloride is avoided, the conversion rate of raw materials is improved, byproducts are reduced, and green and environment-friendly production is realized.
Method for synthesizing pesticide intermediate 2,4-dichloroacetophenone by recycling epoxypropane coproduct
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, (2019/01/21)
The invention belongs to the technical field of organic chemical industry, relates to a preparation method of a halogen-containing aromatic ketone organic compound 2,4-dichloroacetophenone, and concretely relates to a method for synthesizing an important pesticide intermediate 2,4-dichloroacetophenone, for an efficient bactericide propiconazole, a pesticide chlorfenvinphos and a herbicide difenzoquat, from alpha-methylbenzyl alcohol, co-produced through an ethylbenzene co-oxidation technology (PO/SM technology), by halogenation, chlorination, alkaline hydrolysis and oxidation reactions. The total yield is 85% or above, and the purity of the product is 99.7% or above. The method has the advantages of clean process, low raw material cost, high product purity, and easiness in industrialization realization.
Synthetic method of 2,4-dichloroacetophenone
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Paragraph 0032; 0033; 0034-0037, (2019/02/04)
The invention discloses a synthetic method of 2,4-dichloroacetophenone, and the 2,4-dichloroacetophenone is prepared by carrying out electrophilic substitution reaction on m-dichlorobenzene and aceticanhydride as raw materials. According to the method, the electrophilic substitution reaction is carried out by adopting a reaction rectification mode, and the vacuum degree of a reaction rectifying tower is adjusted, and the temperature of the reaction rectifying tower is controlled at optimal temperature for reaction rectification. The single consumption of a catalyst is reduced, the single consumption of the acetic anhydride is reduced, and the production process is simplified.
Synthetic method for 2,4-dichloroacetophenone
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Paragraph 0033-0038, (2019/05/16)
The invention discloses a synthetic method for 2,4-dichloroacetophenone. The method comprises the step of performing an electrophilic substitution reaction by using m-dichlorobenzene and acetic anhydride as raw materials to synthesize the 2,4-dichloroacetophenone. According to the method provided by the invention, the electrophilic substitution reaction is performed by adopting a reactive rectification manner, a vacuum degree of a reaction rectification column is adjusted, temperature of the reaction rectification column is controlled, reactive rectification is performed under the optimal temperature condition, so that the catalyst unit consumption and the acetic anhydride unit consumption are reduced, and the production process is simplified.
Efficient Palladium(0) supported on reduced graphene oxide for selective oxidation of olefins using graphene oxide as a ‘solid weak acid’
Gao, Xi,Zhou, Jianhao,Peng, Xinhua
, p. 73 - 78 (2019/02/06)
Selective oxidation of olefin derivatives to ketones has made innovative development over palladium(0) supported on reduced graphene oxide. Compared to traditional Wacker oxidation, the novel method offers an economical and environment-friendly option by using graphene oxide (GO) as a ‘solid weak acid’ instead of classical homogeneous catalysts like H2SO4 and CF3COOH. X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope and transmission electron microscopy images of Pd0/RGO showed that the nanoscaled Pd particles generated at the flake structure of reduced graphene oxide. Under optimized condition, up to 44 kinds of ketones with different structures can be prepared with excellent yields.
