(1) $ CH_3CHO+ \large\frac{1}{2}O_2\: \: \underrightarrow{Mn(OAc)/air}\: \: CH_3COOH$
(2) $CH_3CH_2OH+O_2\: \: \underrightarrow {Micoderma\: aceti}\: \: CH_3COOH+H_2)$
(3) $ CH_3MgBr\: \: \overset{\overset{(1)CO_2}{\longrightarrow}}{(2)H_3O^{\oplus}}\: \: CH_3COOH+ Mg(OH)Br$
(4) $CH_3OH+CO \:\: \underrightarrow{Ca/\Delta, pressure}\: \: CH_3COOH$
