Baseβinduced disproportionation of nonβenolizable aldehydes (no Ξ±βhydrogen) by concentrated alkali:
$$2\mathrm{HCHO} + \mathrm{NaOH} \rightarrow \mathrm{CH_3OH} + \mathrm{HCOONa}$$$$2\mathrm{ArCHO} + \mathrm{NaOH} \rightarrow \mathrm{ArCH_2OH} + \mathrm{ArCOONa}$$