The LCLD technique attracts an interest due to its possible implementation for in situ laser synthesis of nanostructured metal catalysts directly in the reaction mixture. In this work we studied the catalytic decomposition of ethylene diamine tetraacetic acid (EDTA) accompanied by gaseous hydrogen, ethylene and carbon dioxide release. Laser initiation of the reaction results in the generation of gas phase and its accumulation but shutting off the laser beam let to relaxation EDTA containing solution to the initial state. NMR studies of the reaction mixture before and after laser irradiation reveal that one of the possible reaction mechanisms is elimination of carboxylic groups and substitution of alpha protons in EDTA molecule.