Simple, quick and green isolation of cannabinoids from complex natural product extracts using sustainable mesoporous materials (Starbon®)

The current process to purify cannabidiol (CBD) from C. sativa extract is long and intensive, requiring several steps such as winterification for 48 hours at 45°C and high-temperature, high vacuum distillation. These processes are capital intensive and generate large amounts of toxic solvent waste. In contrast, the solid phase extraction (SPE) methodology proposed herein will change the way CBD is obtained, doing so in a single step that is fast and reusable. Furthermore, the new process is simple and easily implemented and does not require any intensive operator training. Starbon® A300 was successfully employed as the stationary phase in SPE taking Cannabis sativa extract in hexane to selectively physisorb the cannabinoids onto the surface, followed by ethanol to bring about desorption at up to 93 (by GC-FID). A similar one pot system was also proven, using Fedora hemp stem dust as feedstock, with extraction and adsorption in supercritical CO2 followed by desorption in ethanol. © 2022 The Royal Society of Chemistr

Towards the development of a novel “bamboo-refinery” concept : Selective bamboo fractionation by means of a microwave-assisted, acid-catalysed, organosolv process

This work addresses a novel microwave-assisted, acid-catalysed, organosolv (EtOH/H2O) system for the selective fractionation of bamboo, examining the effects of the temperature (110–190 °C), solvent system (EtOH/H2O) and catalyst amount (0–5 vol.% formic acid) on the process. The statistical analysis of the results revealed that the operating variables have a significant influence on bamboo fractionation, allowing the selective production of (i) a cellulose-rich solid fraction, (ii) a hemicellulose rich water-soluble fraction and (iii) a lignin rich solid fraction. The yields of each of these fractions varied between 51 and 94%, 2 and 23% and 2 and 32%, respectively. Increasing temperature exerted a positive effect on bamboo decomposition, increasing the overall bamboo conversion and influencing the effect that the solvent system (EtOH/H2O) has on the process. At low tem- perature (110 °C) the solvent system does not have much influence, while a synergetic interaction between EtOH and H2O took place at higher temperatures, which allowed better results to be obtained with EtOH/H2O mix- tures than with the pure solvents alone. The effect of the catalyst was relatively weak, being greatest when using a high temperature (190 °C) and high proportions of water (> 85 vol.%) in the solvent system. With respect to the properties of each fraction, the cellulose rich solid fraction was made up of un-reacted cellulose (44–83 wt. %), hemicellulose (0–21 wt.%) and lignin (12–34 wt.%); the water-soluble hemicellulose rich fraction consisted of a mixture of oligomers, sugars, carboxylic acids, ketones and furans; and the solid rich lignin fraction com- prised high purity (> 95 wt.%) organosolv lignin. The optimisation of the process revealed that by using a temperature of 190 °C, a solvent system consisting of 45 vol.% EtOH and 55 vol.% H2O with a concentration of formic acid of 5 vol.% it is possible to fractionate bamboo into a high purity (84 wt.%) cellulose solid fraction, very pure (> 95%) organosolv lignin and a rich water-soluble hemicellulose fraction consisting of a mixture of oligomers (27 wt.%), sugars (56 wt.%) and carboxylic acids (14 wt.%); thus converting this process into a very promising method for the selective fractionation of bamboo

NMR and IR study of fluorobenzene and hexafluorobenzene adsorbed on alumina

The adsorption of fluorobenzene (C6H5F) and hexafluorobenzene (C6F6) onto the surface of neutral alumina is investigated by reflectance IR spectroscopy, near-IR spectroscopy, and measurement of 19F NMR chemical shift values. Chemical shifts are dependent on surface coverage and reveal multiple peaks where different adsorption environments occur. C6H5F appears to be adsorbed through polar interactions with surface hydroxyls, whereas C6F6 shows separate resonances for the first layer of coverage and outer layers. Available surface areas are estimated, and reorientation of adsorbed hexafluorobenzene is proposed to account for chemical shift behavior and differences between calculated and measured monolayer coverage

The role of surface functionality of sustainable mesoporous materials Starbon® on the adsorption of toxic ammonia and sulphur gasses

The interest in adsorbing toxic gases nowadays is primarily due to their short- and long-term adverse health effects. It is generally accepted that the pore morphology and the surface nature play key roles in the adsorption mechanism of any molecules. The interactions between the adsorbate and adsorbent are affected by their polarity, where nonpolar surfaces would be attracted to a non-polar adsorbate, while polar surfaces have a higher affinity for polar molecules. The primary issue is access to a controllable set of materials with multiple functionalities that provide both polar and nonpolar surfaces for adsorption, which would present an advantage over single-phase adsorbents. Recently this has become available thanks to a novel class of bio-based carbonaceous materials (Starbon®). The functionality of these materials can be easily controlled by their temperature of preparation. The present work studies the nature of the surface chemistry and porosity of bio-based mesoporous materials Starbon and the role this plays in the adsorption of toxic volatile molecules such as ammonia, as a basic adsorptive and two acidic gasses (hydrogen sulphide and sulphur dioxide) using an InfraSorp optical calorimeter. Both hydrogen sulphide and sulphur dioxide adsorb better onto a hydrophobic surface, while ammonia adsorbs best onto a hydrophilic surface. The results showed that in both cases, Starbon significantly outperformed the industrially available powdered Norit® activated carbon (AC) and reacted chemically with the gasses to some extent

Ball-milled, solvent-free Sn-functionalisation of wood waste biochar for sugar conversion in food waste valorisation

A solvent-free ball milling protocol was investigated for synthesizing sustainable Sn-functionalized biochars for glucose isomerization to fructose. Raw wood biomass (W) and its derived biochars pyrolyzed at low (LB, 400 °C) and high (HB, 750 °C) temperatures were investigated as catalyst supports. This study emphasized that the interactions between Sn and the carbonaceous supports were related to the surface chemistry of the catalysts. Functional group-enriched surfaces provide more active sites for anchoring Sn, resulting in a high loading on the biochar support. Sn was primarily bound with W via surface complexation or precipitation, while it mainly interacted with LB and HB via physical adsorption. The annealing temperature was another critical factor that affected the concentrations and nature of the species of loaded Sn. Catalytic conversion experiments indicated that SnW annealed at 750 °C exhibited the best fructose yield (12.8 mol%) and selectivity (20.2 mol%) at 160 °C in 20 min. The catalytic activity was correlated to the amount and nature of active Sn sites. Reusability tests revealed a noticeable increase in product selectivity compared to pristine materials, despite a compromise in product yield. This study elucidated the roles of the carbon support and annealing temperature for synthesizing biochar-supported catalysts, highlighting a simple and green approach for designing effective solid catalysts for sustainable biorefineries