Characterization of Char from Pyrolysis of Chlorogenic Acid

Abstract

Pyrolysis of chlorogenic acid was studied under varying conditions of temperature and reaction environment. The objective was to study the effect of pyrolysis conditions on the composition of the solid residue, i.e., char. Runs were made at atmospheric pressure under oxidative and non-oxidative (inert) atmospheres and at temperatures ranging from 250 to 750 °C. The characterization of char was done in terms of its elemental composition and surface area, and by Fourier transform infrared (FTIR) and solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. The surface morphology of char was studied by scanning electron microscopy (SEM). The char yield in non-oxidative runs decreased from 80% at 250 °C to 20% above 550 °C. In oxidative runs, the char was completely oxidized at 550 °C. The surface area of char increased with temperature to a maximum of 196 m2/g at 650 °C. SEM analysis indicated that the pyrolysis of chlorogenic acid first formed a melt followed by formation of varying structures that decomposed rapidly at high temperatures. The H/C and O/C ratios of the char decreased as the temperature increased. NMR analysis showed that the resonance bands corresponding to carbonyl groups mostly disappeared above 350 °C and the phenolic groups became almost totally absent in 650 °C char. The aromatic character of char was enhanced with increasing temperature. FTIR studies indicated a gradual decrease in the intensities of OH and CO stretches at high temperatures. At 750 °C, most bands disappeared, resulting in a char that was mainly an aromatic polymer of carbon atoms. The oxidative pyrolysis enhanced mainly the surface area at the expense of char yield. The results are consistent with the analysis of the evolved gases.

Study on the Digestive Behavior of Chlorogenic Acid in Biomimetic Dietary Fiber and the Antioxidative Synergistic Effect of Polysaccharides and Chlorogenic Acid

“…Moreover, the small peak at 171–175 ppm was attributed to C6 (COOH/COOCH 3 ) of pectin, confirming the binding of pectin to BC in the BCP. The CA peaks were consistent with previous findings . The BCP/CA spectrum included the characteristic peaks of BCP, such as the characteristic peaks of C1 and C4 of BCP and C6 of BC; meanwhile, the BCP/CA spectrum also included the characteristic peaks of CA, such as the peak at 39 and 113–146 ppm.…”

“…The CA peaks were consistent with previous findings. 43 The BCP/CA spectrum included the characteristic peaks of BCP, such as the characteristic peaks of C1 and C4 of BCP and C6 of BC; meanwhile, the BCP/CA spectrum also included the characteristic peaks of CA, such as the peak at 39 and 113−146 ppm. This demonstrates the binding of BCP and CA.…”

Promising antioxidant and anticancer (human breast cancer) oxidovanadium(IV) complex of chlorogenic acid. Synthesis, characterization and spectroscopic examination on the transport mechanism with bovine serum albumin

“…1) is an ester formed from caffeic and quinic acids. It contains both aliphatic and aromatic groups and it is one of the major polyphenolic components present in coffee seeds and tobacco leaves [3,4]. Like other polyphenols present in the diet, chlorogenic acid showed antioxidant properties [5], such as antioxidative effects during autoxidation of triacylglycerols of sunflower oil [5], protective effect on blood granulocytes from oxidative stress [6], scavenging ability of N 2 O 3 , organic free radicals, HOCl, O 2 − , • OH, ONOO − and peroxy radical/s [7].…”