Rates of reaction of seven N,N-dialkylformamideacetals R12N–CH(OR2)2 with a series of anilinessubstituted on the phenyl ring have been measured in benzene, methanol, chloroform, and tetrahydrofuran by use of a g.l.c. method. In each case studied reaction is irreversible and obeys a second-order kinetic equation. Reactionrates correlate with Hammett σ constants for substituents on the phenyl ring