Pretreated hemp shives: Possibilities of conversion into levoglucosan and levoglucosenone

[Display omitted] •Hemp shives lignocellulose was used as a raw material.•Al2(SO4)3·18H2O was used as a catalyst for pretreatment and pyrolysis.•Pretreatment promotes the formation of anhydrosugars and excludes competitive reactions.•Washed lignocellulose can be used for production of levoglucosan by fast pyrolysis at 400–500 °C.•Unwashed lignocellulose can be used for production of levoglucosenone by fast pyrolysis at 350 °C. This study aims to evaluate the possibilities of the production of anhydrosugar rich bio-oil by fast pyrolysis. Industrial hemp (Cannabis sativa L.) shives were used as the raw material for the study. Hemicelluloses were converted to furfural by catalytic hydrothermal pretreatment, while the left-over lignocellulose (LC) was subjected to analytical pyrolysis. The impact of the pretreatment time and temperature on the relative contents of LC pyrolysis products – levoglucosan (LG) and levoglucosenone (LGO) – at 350, 400 and 500 °C was investigated. The cellulose structural composition of the left-over LC fraction was analyzed. Results demonstrate that the H2O washed and unwashed LC residue after pretreatment using Al2(SO4)3·18H2O as a catalyst can be used as a feedstock for the production of LG or LGO (up to 38 area% and 24.3 area% content from the detected volatile products by fast pyrolysis, respectively).