Study on Thermal Analysis Kinetics and Pyrolysis Products of Chlorogenic Acid at Different Heating Rates

To have an in-depth understanding of the pyrolysis process and the pyrolysis product release law of chlorogenic acid in tobacco, the effects of heating rates on the pyrolysis behavior, thermal analysis kinetics, and pyrolysis products of chlorogenic acid were investigated by TG-FTIR-GC/MS, coupling with the thermal analysis kinetics methods of Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), and Coats-Redfern. The activation energy E_a and exponential factor A in three pyrolysis stages of chlorogenic acid at different heating rates were calculated by the method of FWO, KAS and Coats-Redfern. It was inferred from the calculation results that the pyrolysis mechanisms of chlorogenic acid in three pyrolysis stages were three-dimensional diffusion control Mample single line rule, the three-dimensional diffusion spherical symmetric Jander equation, and the three-dimensional diffusion G-B equation, respectively. FTIR spectroscopy showed that pyrolysis products of chlorogenic acid in a nitrogen atmosphere mainly included CO₂, a small amount of CO, and typically absorbed -OH functional groups from H₂O, phenol, and carboxylic acids. GC/MS results indicated that the heating rate has a little effect on the chemical categories of pyrolysis products, but has a certain impact on the content of pyrolysis products. The main categories of chlorogenic acid pyrolysis product of at 360 ℃ included phenols benzene derivatives, furans, ketones, aldehydes, heterocycles, etc. This research can provide relevant pyrolysis parameters for the numerical simulation of cigarette products, which could guide the design of “heated not burn” tobacco products and traditional cigarette products.