Pyrolysis technology has a great application prospect in the future. The essential properties of cellulose, pyrolysis mechanism, research tools, catalyst type and other important factors affecting the products distribution are discussed in detail. Particularly, the addition of a variety of catalysts and the optimum design of reaction device can significantly accelerate the cellulose pyrolysis, improve the product distribution and increase the selectivity of some high-value chemicals, thus effectively enhancing the resource and energy utilization value of pyrolysis products. Last but not the least, the future research orientation of cellulose pyrolysis technology is put forward based on some key questions to be solved.

In recent years, the conversion of biomass-derived platform compounds into a variety of high value fuel and chemical products has attracted increasing attention from researchers. 5-Hydroxymethylfurfural (HMF) and furfural (FFR) belong to a class of important biomass-derived platform chemicals. The molecular structure of HMF and FFR is consisted of aldehyde group, furan ring and other functional groups, which endow them with unique chemical properties. In this paper, the research advances on the catalytic hydrogenation of HMF and FFR using various hydrogen sources, such as hydrogen, alcohol, silanes and formic acid, have been reviewed in detail. In addition, the main influencing factors like catalyst type and reaction conditions on the hydrogenation process as well as the reaction mechanism are discussed in depth. Meanwhile, research foreground in the catalytic hydrogenation of HMF/FFR has been prospected.

With the booming of biodiesel industry, it is urgent to high-valued to recycle glycerol as the main by-product. The condensation of glycerol (GLY) with acetone to produce acetone glycidol (2, 2-dimethyl-1, 3-dioxolane-4-methanol, Solketal) is promising direction for GLY utilization, because Solketal can function as fuel additive to modify the fuel viscosity and low-temperature performance of oil significantly, and reduce the emission of carbon monoxide, small solid particles and other environmentally unfriendly substances further. However, the reaction needs to be accelerated by the catalyst with acid nature, thus the design and modification over the structure and acid properties of catalysts are dominating the process of glycerol ketonization reaction. So, this paper systematically reviews the progress of homogeneous and heterogeneous acid catalysts, and the reaction mechanism in recent years. It is classified based on the structural properties, advantages and characteristics of different catalysts, and influences of their structural properties on catalytic activity. Finally, some future directions for this research field are pointed out.

The goal of “carbon peak and carbon neutrality” provides a powerful engine for the transformation of energy structure in China. As response to the sustainable development and energy structure transformation, the development of biomass high-density fuels is necessary, which can provide renewable alternatives for traditional petroleum-based high-density fuels. Herein, the properties and applications of typical petroleum-based high-density fuels including RJ-4 and JP-10 are reviewed. We also introduce the routes for synthesizing RJ-4, JP-10 and other polycyclic fuels from terpenoids and lignocellulose platform compounds, showing the feasibility of converting biomass to high-density fuels. Finally, we emphasize the current bottlenecks and development trends in the synthesis and application of biomass high-density fuels.

In this work, the impacts of ChCl/carboxylic acids, molar ratios of hydrogen bond acceptors to donors, pretreatment temperature and time on the delignification of poplar were investigated. Characteristic methods including XRD, FT-IR, GPC, and HSQC were used to analyze the solid residue and extracted lignin for the study of the structural evolution of the three components. The results showed that under low temperature of 90 ℃, the delignification of poplar wood was 91% with ChCl/FA pretreatment. About 63% of lignin was collected and the purity of lignin was 90%. Over 98% cellulose remained intact with Iβ type crystal form, and the crystallinity was 70%. The β−O−4 bond content of extracted lignin was 84.8% (71% of the original β−O−4 bond), and Mn of the lignin was 1400, suggesting the extracted lignin to be an ideal raw material for monophenlics production.

Acetic acid, phenol, guaiacol and 4-methylguaiacol in bio-oil aqueous fraction were extracted and separated experimentally with the choice of hydrophobic ionic liquid [Bmim][NTf2] as extractant. The effects of extraction time and extractant dosage on the extraction efficiency were explored. With the help of density functional theory (DFT) calculations, the interaction mechanism between [Bmim][NTf2] and phenol was also clarified. The results showed that under the optimal extraction condition (mIL/mW = 0.4, extraction time = 5 min), the extraction efficiencies of acetic acid, phenol, guaiacol and 4-methylguaiacol in the aqueous fraction were 2.71%, 95.41%, 92.04%, and 97.98%, respectively. It was indicated that [Bmim][NTf2] had better selectivity and superior extraction efficiency for phenols in bio-oil aqueous fraction. The results of DFT calculation demonstrated that the strong hydrogen bonding interaction as well as weak vdW interaction between [Bmim][NTf2] and phenols played an important role in extraction and dephenolization of bio-oil aqueous fraction. The phenols in [Bmim][NTf2] can be effectively removed by alkali washing treatment to achieve recovery of [Bmim][NTf2] and next high efficiency extraction.