Question

How would you convert the following?:
i) Alcohol to carboxylic acid
ii) Aldehyde to carboxylic acid

Answer 1

Answer on Question #62707 - Chemistry - Organic Chemistry

Task:

How would you convert the following?:

i) Alcohol to carboxylic acid

ii) Aldehyde to carboxylic acid

Solution:

1) Primary alcohols are oxidized with Jones reagent (solution strictly calculated amount of $\mathrm{CrO}_3$ in aqueous sulfuric acid) to carboxylic acids:

In very rare cases, nitric acid is used as a cheap oxidant. In this case both primary and secondary alcohols are oxidized to carboxylic acids:

2) The aldehydes are readily oxidized to carboxylic acids by the action of a wide variety of oxidizing agents.

Best results are obtained by Jones reagent. In this case, the oxidation is carried out at $0-20^{\circ}$ C during a very short time, and carboxylic acids yields exceed $80\%$:

$$\mathrm{CH_3(CH_2)_4C\overset{O}{\underset{H}{\rightleftarrows}}} \quad \begin{array}{c} \mathrm{CrO_3-H_2O-H_2SO_4} \\ \text{acetone; } 0^{\circ}\mathrm{C} \end{array} \quad \begin{array}{c} \mathrm{CH_3(CH_2)_4C\overset{O}{\underset{85\%}{\rightleftarrows}}} \end{array} \quad (85\%)$$

An ideal selective oxidizing agent is an aqueous-alcoholic ammonia solution of silver oxide (Tollens reagent). This reagent does not affect the carbon-carbon double or triple bond, hydroxyl group of alcohols, etc.:

\mathrm{CH_3CH_2C=C\overset{CHO}{\underset{CH_3}{\rightleftarrows}} \quad \begin{array}{c} \mathrm{Ag_2O} \\ \mathrm{H_2O; NH_3} \end{array} \quad \begin{array}{c} \mathrm{H_2C=C\overset{COOH}{\underset{CH_3}{\rightleftarrows}}} \quad (98\%) \end{array}

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