| 查看: 281 | 回复: 0 | ||
[求助]
求翻译成汉语，要专业一些，语句通顺，不要直接谷歌翻译，3q
|
|
The use of nitroxyl radicals, alone or in combination with transition metals, as catalysts in oxidation processes is reviewed, from both a synthetic and a mechanistic viewpoint. Two extremes of reactivity can be distinguished: stable (persistent) dialkylnitroxyls, such as TEMPO, and reactive diacylnitroxyls, derived from N-hydroxy imides, such as N-hydroxyphthalimide (NHPI). NHPI catalyzes a wide variety of free radical autoxidations, improving both activities and selectivities by increasing the rate of chain propagation and/or decreasing the rate of chain termination. In the absence of metal cocatalysts improved conversions and selectivities are obtained in the autoxidation of hydrocarbons to the corresponding alkyl hydroperoxides. In combination with transition metal cocatalysts, notably cobalt, NHPI and related compounds, such as N-hydroxysaccharin (NHS), afford effective catalytic systems for the autoxidation of hydrocarbons, e.g. toluenes to carboxylic acids and cycloalkanes to the corresponding ketones. Stable dialkylnitroxyl radicals, exemplified by TEMPO, catalyze oxidations of, e.g. alcohols, with single oxygen donors such as hypochlorite via the intermediate formation of the corresponding oxoammonium cation. Alternatively, in conjunction with transition metals, notably ruthenium and copper, they catalyze aerobic oxidations of alcohols via metal-centred dehydrogenation. The role of the TEMPO is to facilitate regeneration of the catalyst (Ru and Cu). In contrast, oxoammonium cations are involved in the aerobic oxidation of alcohols catalyzed by the copper-dependent oxidase, laccase, in combination with TEMPO. This different mechanistic pathway is attributed to the much higher redox potential of the copper(II) in the enzyme. |
回复此楼» 猜你喜欢
有时候真觉得大城市人没有县城人甚至个体户幸福
已经有11人回复
-
表哥与省会女结婚，父母去帮带孩子被省会女气回家生重病了
已经有7人回复
-
同年申请2项不同项目，第1个项目里不写第2个项目的信息，可以吗
已经有8人回复
-
依托企业入选了国家启明计划青年人才。有无高校可以引进的。
已经有7人回复
-
依托企业入选了国家启明计划青年人才。有无高校可以引进的。
已经有10人回复
-
天津大学招2026.09的博士生，欢迎大家推荐交流（博导是本人）
已经有9人回复
-
有院领导为了换新车，用横向课题经费买了俩车
已经有10人回复
-
AI 太可怕了，写基金时，提出想法，直接生成的文字比自己想得深远，还有科学性
已经有6人回复
