Thermal transformations of biologically active derivatives of cinnamic acid by TPD MS investigation

Pyrolysis of biologically active cinnamic acid derivatives: cinnamic, coumaric, ferulic and caffeic acids was studied by the method of thermal programmed desorption mass spectrometry. It was found that pyrolysis of coumaric and caffeic acid proceeds as a thermal decarboxylation reaction of the first order. Kinetic parameters of the reaction of decarboxylation including its order, the activation energy and pre-exponential factor were calculated. Under conditions of TPD MS experiment cinnamic acid sublimates at temperatures above 200 °C. Thermal decomposition of ferulic acid proceeds in several stages.