Hydrothermal conversion of glucose in a batch reactor. A detailed study of an experimental key-parameter: The heating time

[Display omitted] ► In this study we study the hydrothermal conversion of glucose at 370 °C and 25 MPa with different heating time in an original batch reactor. ► We have characterized product chemical structures and molecular weights with a multitechnique analytical approach. ► We find that the glucose reaction pathway involves competitive fragmentation and condensation reactions and that the condensation reactions are limited mainly by both short heating and reaction time. In this study, conversions of an aqueous solution of glucose (2 wt%) were performed at 370 °C and 25 MPa in subcritical water during different heating times. The original batch reactor used for this study allowed the introduction of the glucose solution directly in the hot and compressed aqueous medium. In this work, an original analytical approach combining chromatographic (SEC, GC, HPLC) and mass spectrometric techniques (FT-ICR/MS) has been also developed in order to provide more information about the chemical and molecular weights polydispersity of the products. From our experiments, it has been shown that the glucose conversion occurs via a complex reaction pathway implying competitive fragmentation and condensation reactions. Yields of product resulting from condensation reactions can be limited mainly by both short heating time and reaction time.