Investigation of functional group changes in biomass during slow pyrolysis using synchrotron based infra-red microspectroscopy and thermogravimetry-infra-red spectroscopy

- Temperature range for platform chemical production from biomass is identified.
- Synchrotron IR and TGIR are used to study functional group changes in biomass.
- Most of the functional groups on the biomass surface disappear by 400 °C.
- Majority of the volatile organic compounds evolve between 200 and 400 °C.
- Possible reactions for functional group changes are outlined.

This study investigates the functional group changes that occur in biomass during slow pyrolysis to identify a temperature range suitable for conversion of biomass to platform chemicals. The synchrotron based infra-red (IR) micro-spectroscopy and thermogravimetry-infra-red spectroscopy (TGIR) coupled analysis have been used in this study to examine the functional group changes in three different types of biomass samples. Synchrotron IR results show that the onset of chemical changes on biomass occurs at 200 °C and most of the surface functional groups disappear by 400 °C. The TGIR analysis shows majority of the volatile species are liberated between 200 and 400 °C and major mass loss happens between 195 and 432 °C for all the biomass samples. The functional groups on biomass surface that liberate volatile species like aromatics, alcohols and alkanes and the possible reaction mechanism have also been identified. The results of this study suggest that the ideal temperature range to study the thermochemical conversion of biomass to platform chemicals is 200-400 °C.