A Comparative Study of Pyrolysis Liquids by Slow Pyrolysis of Industrial Hemp Leaves, Hurds and Roots

Abstract

This study assessed the pyrolysis liquids obtained by slow pyrolysis of industrial hemp leaves, hurds, and roots. The liquids recovered between a pyrolysis temperature of 275–350 °C, at two condensation temperatures 130 °C and 70 °C, were analyzed. Aqueous and bio-oil pyrolysis liquids were produced and analyzed by proton nuclear magnetic resonance (NMR), gas chromatography–mass spectrometry (GC-MS), and atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry (APPI FT-ICR MS). NMR revealed quantitative concentrations of the most abundant compounds in the aqueous fractions and compound groups in the oily fractions. In the aqueous fractions, the concentration range of acetic acid was 50–241 gL−1, methanol 2–30 gL−1, propanoic acid 5–20 gL−1, and 1-hydroxybutan-2-one 2 gL−1. GC-MS was used to compare the compositions of the volatile compounds and APPI FT-ICR MS was utilized to determine the most abundant higher molecular weight compounds. The different obtained pyrolysis liquids (aqueous and oily) had various volatile and nonvolatile compounds such as acetic acid, 2,6-dimethoxyphenol, 2-methoxyphenol, and cannabidiol. This study provides a detailed understanding of the chemical composition of pyrolysis liquids from different parts of the industrial hemp plant and assesses their possible economic potential.

Phytochemical Contents of Essential Oils from Cymbopogon Species: A Tropical Medicinal Plant

“…This is determined by measuring the chemical shift arising from variations in the strength of the applied magnetic field, the chemical environment, and changes in the magnetic characteristics of the various nuclei [54,89]. The quantitative concentrations of the most abundant compounds in the oily fractions of hemp leaves, hurds, and roots were revealed by the NMR method [92][93][94].…”

A paradigm shift towards production of sustainable bioenergy and advanced products from Cannabis/hemp biomass in Canada

“…Drop-in oils do not contain any polyaromatic hydrocarbon and sulfur components and consequently emit no CO and particulate matter (PM) on burning; hence, it can be utilized as a straight substitute for petroleum-based fuels such as gasoline, diesel, and jet fuel [ 146 ]. It was recently detected that hemp seed oil directly contains drop-in oils, mainly, alkanes and alkenes [ 147 ]. The short or medium-chain fatty acids are well-known precursors of alkanes and alkenes [ 148 , 149 ].…”

Characterization of the Compounds Released in the Gaseous Waste Stream during the Slow Pyrolysis of Hemp (Cannabis sativa L.)

“…Additionally, components from the waste streams presented interesting properties such as antioxidant activity, antimicrobial, antiviral, or anti-allergenic effect, food additives and fragrances [15][16][17][18]. Salami et al [19] investigated the potential of using slow pyrolysis of hemp shives, roots and leaves, and characterized the liquids retrieved when temperatures were between 275-350 • C. Their research found that the pyrolysis processing of hemp materials resulted in recovered acetic acid, 2,6-dimethoxyphenol, 2methoxyphenol, and cannabidiol liquids. In a similar study, the resulting distillates of three types of hemp shives heated using slow pyrolysis up to 350 • C were identified to produce baseline data for potential hemp valorization [20].…”