The hydrogen abstraction reactions from CH3CHO by OH and OD radicals were studied in a fast-flow reactor by observation of the infrared chemiluminescence from H2O and HOD. The fraction of available energy released as the vibrational energy of water was [f(v)] = 0.52 with similar to 30% released as bending excitation and similar to 65% released as stretching excitation of the newly formed OH bond. The pattern of energy disposal closely resembles that for OH + H2CO or (CH3)(2)S reactions, but differs from abstraction from secondary C-H bonds of hydrocarbons. Secondary reactions of CH3CO radical with NO2, OH, and H also were observed by infrared emission of products formed from the unimolecular decomposition of CH3F(O)ONO, CH3C(O)OH, and CH3C(O)H intermediate adducts. The CO2 vibrational distributions from the decomposition of CH3C(O)OH, CH3C(O)ONO, and HC(O)ONO are compared.