定义Definition
琼斯氧化是用琼斯试剂（CrO₃ 溶于稀硫酸）在丙酮中把仲醇氧化为酮、伯醇氧化为羧酸的反应；铬由橙红色的 Cr(VI) 变为绿色的 Cr(III)。
The Jones oxidation uses Jones reagent — CrO₃ in dilute sulfuric acid — in acetone to oxidise secondary alcohols to ketones and primary alcohols to carboxylic acids; chromium changes from orange Cr(VI) to green Cr(III).
机理Mechanism
醇与铬酸生成铬酸酯；碱（水）夺取醇碳上的 H，同时 Cr–O 键断裂、Cr(VI) 被还原为 Cr(IV)，生成羰基。伯醇先生成醛，醛在水中形成水合物后被进一步氧化为羧酸。
The alcohol forms a chromate ester; water removes the carbinol H as Cr(VI) is reduced to Cr(IV), giving the carbonyl. Primary alcohols give aldehydes whose hydrates are oxidised further to acids.
由来Origin
英国化学家埃瓦特·琼斯（E. R. H. Jones）等于 1946 年报道。
Reported in 1946 by Ewart R. H. Jones and co-workers.
比较与环保Comparisons and environment
反应快、便宜、颜色变化便于监测，也是呼气酒精检测仪（重铬酸钾变色）的化学原理。PCC、PDC（无水条件）可把伯醇停在醛阶段。Cr(VI) 有致癌性，现代实验室多改用斯文、德斯–马丁或 TEMPO 氧化。
Fast, cheap and self-indicating — the same chemistry as dichromate breathalysers. PCC and PDC (anhydrous) stop primary alcohols at the aldehyde. Because Cr(VI) is carcinogenic, labs increasingly use Swern, Dess–Martin or TEMPO oxidations.
反应Reactions
丙酮中 0 °C 滴加琼斯试剂至橙色不褪；异丙醇淬灭过量试剂
Add Jones reagent to the alcohol in acetone at 0 °C until the orange colour persists; quench excess with isopropanol
生成铬酸酯。
Chromate ester formation.
C–H 断裂与 Cr(VI) 还原协同发生，生成羰基。
C–H cleavage with Cr(VI) reduction gives the carbonyl.
伯醇的醛水合物继续被氧化为酸。
Aldehyde hydrates of primary alcohols are oxidised to acids.
经典仲醇氧化。
Classic secondary alcohol oxidation.
年表Timeline
- 1946
琼斯等报道该方法
Jones and co-workers report the method
- 1975
科里报道 PCC
Corey reports PCC