Molecular products from the pyrolysis and oxidative pyrolysis of tyrosine

The thermal degradation of tyrosine at a residence time of 0.2 s was conducted in a tubular flow reactor in flowing N2 and 4% O2 in N2 for a total pyrolysis time of 3 min. The fractional pyrolysis technique, in which the same sample was heated continuously at each pyrolysis temperature, was applied. Thermal decomposition of tyrosine between 350 and 550 °C yielded predominantly phenolic compounds (phenol, p-cresol, and p-tyramine), while decomposition between 550 and 800 °C yielded hydrocarbons such as benzene, toluene, and ethyl benzene as the major reaction products. For the first time, the identification of p-tyramine, a precursor for the on of formation of p-tyramine and its degradation to phenol and p-cresol, and toxicological discussion of some of the harmful reaction products is also presented.

► Thermal degradation of tyrosine in N2 and 4% O2 in N2 using the System for Thermal Diagnostic Studies (STDS). ► Product distribution of major reaction products with degradation temperature. ► A detailed mechanistic description of formation of p-tyramine and its degradation to phenol and p-cresol. ► Biological compounds of interest including dibenzo-p-dioxin, dibenzofuran, hydroquinone and p-benzoquinone. ► The environmental and biological impacts of toxic compounds from the thermal degradation of tyrosine.