KINETICS OF THE AMINOLYSIS AND HYDROLYSIS OF ALKYL NITRITES - EVIDENCE FOR AN ORBITAL CONTROLLED MECHANISM

The kinetics of the nitrosation of piperidine by propyl, iso-propyl, b utyl, iso-butyl, sec-butyl, and tert-butyl nitrites in 0.1 M NaOH and of the hydrolysis of the nitrite esters were studied spectrophotometri cally by monitoring the absorbance of the nitrites at 381 nm. The obse rved correlation between log k(2) and sigma (rho* = 4.5) shows the re action to proceed via electrophilic attack by the nitrites; the existe nce of an isokinetic relationship suggests a single mechanism for the whole series. Comparison of the relative reactivities of the alkyl nit rites (primary > secondary > tertiary) with characteristic parameters of their R groups (vertical ionization potentials and heats of formati on of R(+)) suggests that these reactions are orbital controlled. All hydrolysis reactions were slower than the corresponding aminolysis rea ctions. This is attributed to a retardation of the former reaction by unfavourable interactions between the lone pairs of the nucleophile an d the nitroso nitrogen atom.