Is there a way to oxidize salicyl alcohol to salicylic acid without using chromium trioxide? [closed]








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I'm doing a project for school and I need to convert salicyl alcohol to salicylic acid, but I'm not allowed to use $\ce{CrO3}$ because of its toxicity. I know it is also possible to oxidize a primary alcohol to a carboxylic acid with potassium permanganate, but I read it might be a too strong oxidizer. Is there any good alternative?




@Waylander: A general Procedure given in [*J. Org. Chem.* **1999**, *64(7)*, 2564–2566](https://pubs.acs.org/doi/10.1021/jo982143y) as follows:



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> **Typical Procedure.** A mixture of alcohol **1** ($\pu{40 mmol}$), **TEMPO** ($\pu{436 mg}$, $\pu{2.8 mmol}$), $\ce{MeCN}$ ($\pu{200 mL}$), and sodium phosphate buffer ($\pu{150 mL}$, $\pu{0.67 M}$, $\pu{pH = 6.7}$) is heated to $\pu{35 °C}$. Then mixtures of $\pu{9.14 g}$ of 80% sodium chlorite ($\ce{NaClO2}$, $\pu{80.0 mmol}$) in $\pu{40 mL}$ of water and 2.0 mol% dilute bleach ($\pu{1.06 mL}$ of 5.25% $\ce{NaOCl}$ diluted into $\pu{20 mL}$ with water) are added simultaneously over $\pu{2 h}$ (Caution! Do not mix bleach and $\ce{NaClO2}$ before being added to the reaction mixture). The mixture is stirred at $\pu{35 °C}$ until the reaction is complete (<2% starting material, $\pu{2−5 h}$ reaction time), then cooled to room temperature. Water ($\pu{300 mL}$) is added, and the $\mathrm{pH}$ is adjusted to $8.0$ with $\pu{2.0 N}$ $\ce{NaOH}$ (about $\pu{48 mL}$). The reaction is quenched by pouring into cold ($\pu{0 °C}$) $\ce{Na2SO3}$ solution ($\pu{12.2 g}$ in $\pu{200 mL}$ of water) maintained at $\pu{<20 °C}$. The $\mathrm{pH}$ of the aqueous layer should be $8.5$−$9.0$. After stirring for $\pu{0.5 h}$ at room temperature, methyl *tert*-butyl ether (**MTBE**, $\pu{200 mL}$) is added. The organic layer is separated and discarded. More **MTBE** ($\pu{300 mL}$) is added, and the aqueous layer is acidified with $\pu{2.0 N}$ $\ce{HCl}$ (~$\pu{100 mL}$) to $\pu{pH = 3−4}$. The organic layer is separated, washed with water ($2 \times \pu{100 mL}$) and brine ($\pu{150 mL}$), and then concentrated to give the crude carboxylic acid **2** in 85−100% yield. The products may be purified by silica gel column chromatography or crystallization.
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Converting alcohol to carboxylic acid requires strong oxidizing agent and those reagents are not commonly in school laboratory. In that case, mild oxidizing agent should be used to first convert salicyl alcohol to salicylaldehyde and then convert to salicylic acid.


You should try [$\ce{MnO2}$ or (Conc. $\ce{HCl}$, ethyl acetate, sodium Hypo (8 - 12%))](https://www.google.co.in/amp/s/www.researchgate.net/post/Which_reagent_will_work_to_oxidize_salicyl_alcohol_to_salicylaldehyde/amp) and then [use $\ce{KMnO4}$ to convert it to salicylic acid.](https://chemistry.stackexchange.com/questions/5006/can-salicylic-acid-be-synthesized-from-salicylaldehyde)


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