有许多方法可以将醛酮还原成醇。如用硼烷、甲醛等都能将醛或酮还原成醇。 用醛还原醛可以蒋醛酮还原成醇， 另一方面甲醛则被氧化为甲酸。

    The apparatus consists of a 3-l. three-necked flask fitted with a mercury-sealed mechanical stirrer, a reflux condenser, a dropping funnel, and a thermometer which reaches almost to the bottom of the flask. Five hundred grams of potassium hydroxide pellets (85 per cent potassium hydroxide) (7.6 moles) and 750 cc. of commercial absolute methyl alcohol (free from acetone) are placed in the flask, and stirring is begun. The bulk of the alkali dissolves in a few minutes, with the evolution of heat. The flask is now surrounded by an ample cold-water bath, and, when the internal temperature drops to 60°, addition of a mixture of 360 g. (353 cc., 3 moles) of p-tolualdehyde, 300 cc. of formalin (3.9 moles), and 300 cc. of absolute methyl alcohol is begun at such a rate that the internal temperature remains at 60–70 ℃. This addition requires about fifteen minutes. The internal temperature is then maintained  at 60–70℃ for three hours, after which the reflux condenser is replaced by a downward condenser and the methyl alcohol distilled with the aid of a brine bath until the internal temperature reaches 101℃. Nine hundred cubic centimeters of cold water is then added to the warm residue, and the mixture is cooled. The resulting two layers are separated at once, and the aqueous layer is extracted with three 200-cc. portions of benzene. The combined oil and extracts are washed with five or six 50-cc. portions of water, and the combined washings extracted with 50 cc. of benzene, the benzene layer being added to the washed extract. The benzene solution is cleared by shaking it with a few grams of anhydrous sodium sulfate and is then distilled under diminished pressure. After removal of the benzene, 331 g. (90 per cent of the theoretical amount) of p-tolyl carbinol (b.p. 116–118℃/20 mm.) is obtained; the product solidifies in the receiver to a mass of oil-drenched crystals melting at 54–55℃. Recrystallization from an equal weight of commercial heptane (b.p. 90–100℃) gives an 80 per cent recovery of long needles which melt at 61℃. A further 8 per cent is recoverable by concentration of the mother liquor.