615-67-8Relevant articles and documents
Photochemistry of Semiconductor Particles. Part 4. - Effects of Surface Condition on the Photodegradation of 2,4-Dichlorophenol catalysed by TiO2 Suspensions
Zang, Ling,Liu, Chun-Yan,Ren, Xin-Min
, p. 917 - 924 (1995)
The photocatalysed degradation of 2,4-dichlorophenol (DCP) has been investigated in aqueous suspensions of TiO2.A possible reaction scheme has been proposed for the degradation, in which chlorobenzoquinone (CBQ) was detected as a predominant intermediate present in the reaction solution.Kinetic details for the degradation steps have been analysed based on the experimental results.The essential role of oxygen was considered to be the capturing of the photogenerated electron to form the oxidizing species, such as H2O2, HO2(.) and OH(.).In anaerobic conditions, the photodegradation rate was quite low even with the adsorbed Cu(2+) ion on the TiO2 powder as an alternative electron scavenger.This is due to the rapid indirect recombination of the photogenerated electron and hole, which is mediated by the short-circuiting reaction of Cu(2+).However, in aerobic conditions, oxygen takes up the photogenerated electron trapped at the adsorbed Cu(2+) ion to prevent it from recombining with the photogenerated hole.As a result, the hole has sufficient opportunity to participate in the oxidizing reactions.The degradation rate was dependent to some extent on the surface charge of the TiO2 particles.Positive charge always promotes the photodegradation, whereas negative change is detrimental.This was attributed to the effects of surface charge on the migration of electrons from the interior of the TiO2 particles to the surface.
Photochemical transformations of 2, 6-dichlorophenol and 2-chlorophenol with superoxide ions in the atmospheric aqueous phase
Dong, Linchang,Hu, Shuheng,Lu, Jun,Peng, Shuchuan,Zhu, Chengzhu,Zhu, Mengyu
, (2022/04/03)
The possible photochemical transformation pathways of chlorophenols (2, 6-dichlorophenol and 2-chlorophenol) with superoxide anion radical (O2·?) were studied by steady-state irradiation and 355 nm laser flash photolysis technique. O
Iron-catalyzed arene C-H hydroxylation
Cheng, Lu,Wang, Huihui,Cai, Hengrui,Zhang, Jie,Gong, Xu,Han, Wei
, p. 77 - 81 (2021/10/05)
The sustainable, undirected, and selective catalytic hydroxylation of arenes remains an ongoing research challenge because of the relative inertness of aryl carbon-hydrogen bonds, the higher reactivity of the phenolic products leading to over-oxidized by-products, and the frequently insufficient regioselectivity. We report that iron coordinated by a bioinspired L-cystine-derived ligand can catalyze undirected arene carbon-hydrogen hydroxylation with hydrogen peroxide as the terminal oxidant. The reaction is distinguished by its broad substrate scope, excellent selectivity, and good yields, and it showcases compatibility with oxidation-sensitive functional groups, such as alcohols, polyphenols, aldehydes, and even a boronic acid. This method is well suited for the synthesis of polyphenols through multiple carbon-hydrogen hydroxylations, as well as the late-stage functionalization of natural products and drug molecules.
Preparation method of 2,5-dimethoxychlorobenzene
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Paragraph 0029-0031; 0034-0037, (2020/12/15)
The invention relates to a preparation method of 2,5-dimethoxychlorobenzene, which comprises the following steps: 1) one-pot oxidatiion and chlorination: dissolving phenol in a solvent, putting a formed solution into a high-pressure reaction kettle, adding a copper salt catalyst, conducting stirring to conduct reaction at a temperature range of room temperature to 50 DEG C under the oxygen pressure of 0.5-3 MPa, introducing 0.1-2 MPa dry HCl gas into the solution after the reaction is completed, and conducting stirring to conduct reaction at room temperature, and after the reaction is completed, conducting decompressing and rectifying to obtain a 2-chlorohydroquinone intermediate; and 2) methylation: adding 2-chlorohydroquinone into a high-pressure reaction kettle, conducting dissolving, introducing 0.1-2MPa of chloromethane gas under an alkaline condition, maintaining the pressure, conducting reacting at 50-120 DEG C until the raw materials are completely consumed, conducting filtering and desolventizing, and carrying out reduced pressure distillation to obtain the product 2,5-dimethoxychlorobenzene. Compared with a traditional preparation method, the method has the advantages ofless emission of three wastes, low cost, environmental friendliness and the like.
