Chien-hua Niu

Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)




The ultraviolet irradiation of ammonia-saturated liquid cyclohexane produces two products, cyclohexylamine in a photostationary state and cyclohexylcyclohexane. It is assumed that ammonia is responsible for the initial light absorption which leads to the observed reaction products.

The products and rates of product formation have been determined for the ultraviolet irradiation of cyclohexylamine, cyclopentylamine, and n-hexylamine in saturated hydrocarbon solvents. The results demonstrate that (1) imines are produced during the irradiation, (2) ammonia is isolated and identified, (3) both carbon-nitrogen and nitrogen-hydrogen bonds cleave to varying degrees during the irradiation, and (4) the cleavage pattern is dependent on the stability of the alkyl radicals produced.

Direct ultraviolet irradiation of the secondary amines, _i..e., di-n- hexylamine, dicyclohexylamine, and n-hexylcyclohexylamine in cyclohexane liquid solution, produces the corresponding imine in preparative yields (89-91%).

The primary process of the photooxidation of cyclohexylamine is determined as charge-transfer excitation by the light absorption dependence of the reaction. The primary products are cyclohexanone oxime, N- cyclohexylidenecyclohexylamine, ammonia, and water. Synthesis and studies of 1-hydroperoxycyclohexylamine show that it is probably the precursor for N-cyclohexylidenecyclohexylamine . Cyclohexanone oxime is presumably generated from the thermal or photodecomposition of N- hydroperoxycyclohexylamine. Hydrogen peroxide is probably present in the photomixture of cyclohexylamine. When ionization potentials of aliphatic amines are plotted versus the frequency of charge-transfer bands, a linear relationship is obtained .

The relative rates of oxygen uptake during the photooxidation of cyclic hydrocarbons show that the carbon-hydrogen rather than carbon- carbon bond is the donor in the contact charge-transfer process between oxygen and the hydrocarbon.