Low-Temperature Deoxidization of Lignin and Its Impact on Liquid Products from Pyrolysis

Abstract

In this study, low temperature deoxidization of lignin at temperature range of 200~390°C as a pretreatment method had been exploited to gain high quality pyrolysis products. A two-dimensional infrared correlation spectroscopy (2D-PCIS) was used to analyze the evolution of the functional groups of lignin in the process of low temperature deoxidization, and the deoxidized samples were pyrolysed in the pyrolysis gas chromatography mass spectrometry (Py-GC/MS). The results of 2D-PCIS showed that the decomposition of the lignin was accelerated from 320 °C and which was dominated by the elimination reaction. Notably, aromatization reaction was intensified at 350 °C, whereas the structure of lilac aromatic ring was more stable than the guaiac aromatic. It was also found that the alcohol hydroxyl group was significantly removed, and due to this removal other functional groups also underwent changes during the deoxidization. The results from Py-GC/MS experiments showed that deoxidization treatment at lower than 230 °C had insignificant effect on the pyrolysis products. However, when the deoxidization temperature was at 230°C and above, the oxygen-containing compounds in the pyrolysis liquid products (mainly phenols) decreased significantly, and when the deoxidization temperature was above 290 °C, hydrocarbons were the main compounds in the pyrolysis liquid product.

Two-Dimensional Perturbation Correlation Infrared Spectroscopy for Probing Pyrolysis of Biomass: Fundamentals, Applications, and Mechanistic Understanding

“…Mei et al investigated lignin pyrolysis in the temperature range of 200–400 °C. They found that the lignin decomposition reaction accelerated at temperatures greater than 320 °C and that the aromatization reaction intensified at 350 °C.…”

“…As the pyrolysis temperature increases, a larger number of hydrogen bonds are converted to free −OH groups. 100 Mei et al 122 investigated lignin pyrolysis in the temperature range of 200−400 °C. They found that the lignin decomposition reaction accelerated at temperatures greater than 320 °C and that the aromatization reaction intensified at 350 °C.…”

Poly(divinylbenzene-maleic acid) Hollow Nanospheres Coordinated with Zirconium: An Effective Catalyst for the Catalytic Transfer Hydrogenation of Furfural to Furfuryl Alcohol

“…The peaks at 1223 and 1076 cm –1 are the stretching vibration absorption peaks of the C–O and C–O–C bonds of the anhydride ring . The peaks at 1496 and 1600 cm –1 were assigned to the vibration absorption peaks of the benzene ring skeleton . In the FTIR spectrum of PDBMA, the typical characteristic peaks (1850 and 1778 cm –1 ) of anhydride disappeared.…”

“…27 The peaks at 1496 and 1600 cm −1 were assigned to the vibration absorption peaks of the benzene ring skeleton. 28 In the FTIR spectrum of PDBMA, the typical characteristic peaks (1850 and 1778 cm −1 ) of anhydride disappeared. The peak at 1715 cm −1 is due to the C�O stretching vibration.…”

Highly effective and chemoselective hydrodeoxygenation of aromatic alcohols

“…To date, researchers have developed many methods for chemoselective HDO of oxygen-containing molecules, such as alcohols, aldehydes, ketones, amides and nitrogencontaining compounds. [21][22][23] Among them, alcohols are widely used as versatile precursors for the production of other organic molecules in the chemical industry. The selective HDO of alcohols is one of the most fundamental transformations in organic chemistry and plays a crucial role in the total synthesis of complex natural products bearing multifunctional groups.…”