Effect of Reaction Conditions on Catalytic and Noncatalytic Lignin Solvolysis in Water Media Investigated for a 5 L Reactor

Abstract

The high content of oxygen in the lignin polymer and the prevalence of phenolic functional groups make the conversion of lignin to fuels and value-added products with well-defined chemical properties challenging. The lignin-to-liquid process using a water/formic acid reaction medium has been shown to convert the lignin polymer to monomers with a molecular weight range of 300–600 Da. The bio-oil comprises a complex mixture of monomeric phenols, aromatics, and aliphatic hydrocarbons with a high H/C and low O/C ratio. This study investigates the effect of the stirring rate, level of loading, and catalyst at 305 and 350 °C in a 5 L pilot scale reactor. The oil yields are found to be highest for experiments conducted using the maximum stirring rate, maximum level of loading, and Ru/Al2O3 catalyst with yields of more than 69 wt % on lignin intake. Goethite as a catalyst does not show good conversion efficiency at either reaction temperatures. The carbon recovery is highest for products produced at 305 °C. Furthermore, results from solid phase extraction on a DSC-CN solid phase show that 65–92 wt % the bio-oils can be recovered as fractions separated based on polarity.

An effective strategy to produce highly amenable cellulose and enhance lignin upgrading to aromatic and olefinic hydrocarbons

“…These results show that deoxygenation is mainly carried out through solvolysis, while the transition metal catalysts are primarily Please do not adjust margins Please do not adjust margins involved in the hydrogenation of the produced fragments. 40 These observations are consistent with recent studies that found that the catalyst was merely responsible for the hydrogenation of the unsaturated sidechains in the solubilized lignin intermediates, while the solvent was primarily involved in the fragmentation of lignin. [41][42][43] Pd/C had a superior ability to hydrogenate the intermediates compared to other tested catalysts.…”

Synergistic effect of Fenton pretreatment and hydrothermal carbonization of lignin on the physicochemical properties of the resulting hydrochar

“…In addition, the recycling of lignocellulosic biomass is of great significance for improving the environment and alleviating the energy crisis. 11,12 Unfortunately, although lignin is considered to be the second most abundant terrestrial macromolecule in the world, its full potential has not been fully realized and further research is needed. 13,14 Lignocellulosic biomass is mainly a natural aromatic polymer composed of two basic structural units, guaiacyl [G] and syringyl [S] (the majority of natural herbal lignin structures also contain p-hydroxyphenyl units [H]), 15,16 which are connected by different ether bonds (4-O-5, α-O-4, β-O-4 and α-O-β) and C-C bonds (β-1, β-β and 5′-5).…”

Research and Mechanism of Two-step Preparation of Acetamide from Microalgae under Hydrothermal Conditions

“…Ionic product (Kw) of HTW, about 1000 times higher than that of ambient liquid water [16], and the low dielectric constant, are both favourable to promote reactions without catalysts and have a good selectivity on the products [12,14]. HTW also haves the good transport property to mix small organic compounds completely and break down hydrocarbons and carbohydrates [17][18][19]. Most importantly, compared to other ways, the hydrothermal treatment of microalgae does not require dehydration, which could save a great deal of energy in the period of pretreatment [1,19].…”