The ever increasing industrial production of commodity and specialty chemicals inexorably depletes the finite primary fossil resources available on Earth. The forecast of population growth over the next 3 decades is a very strong incentive for the identification of alternative primary resources other than petro-based ones. In contrast with fossil resources, renewable biomass is a virtually inexhaustible reservoir of chemical building blocks. Shifting the current industrial paradigm from almost exclusively petro-based resources to alternative bio-based raw materials requires more than vibrant political messages; it requires a profound revision of the concepts and technologies on which industrial chemical processes rely. Only a small fraction of molecules extracted from biomass bears significant chemical and commercial potentials to be considered as ubiquitous chemical platforms upon which a new, bio-based industry can thrive. Owing to its inherent assets in terms of unique process experience, scalability, and reduced environmental footprint, flow chemistry arguably has a major role to play in this context. This review covers a selection of C2 to C6 bio-based chemical platforms with existing commercial markets including polyols (ethylene glycol, 1,2-propanediol, 1,3-propanediol, glycerol, 1,4-butanediol, xylitol, and sorbitol), furanoids (furfural and 5-hydroxymethylfurfural) and carboxylic acids (lactic acid, succinic acid, fumaric acid, malic acid, itaconic acid, and levulinic acid). The aim of this review is to illustrate the various aspects of upgrading bio-based platform molecules toward commodity or specialty chemicals using new process concepts that fall under the umbrella of continuous flow technology and that could change the future perspectives of biorefineries.

Continuous Flow Upgrading of Selected C2-C6 Platform Chemicals Derived from Biomass.

Supported metal nanoparticles, M-NPs, are of great scientific and economic interest as they encompass application in chemical manufacturing, oil refining and environmental catalysis. Oxidation and hydrogenation reactions are among the major reactions catalyzed by supported M-NPs. Although supported M-NPs are preferable due to their easy recovery and reuse, there are still some practical issues regarding their catalytic activity and deactivation. This review highlights the general features of supported M-NPs as catalysts with particular attention to copper, gold, platinum, palladium, ruthenium, silver, cobalt and nickel and their catalytic evaluation in various reactions. The catalytic performance of noble M-NPs has been explored extensively in various selective oxidation and hydrogenation reactions. In general, noble metals are expensive and sensitive to poisons. Despite their significant merits and potential (easily available, comparatively inexpensive and less sensitive to poisons), catalysis by base M-NPs is relatively less explored. Therefore, activity of base M-NPs can be improved, and still, there is potential for such catalysts.

Review of supported metal nanoparticles: synthesis methodologies, advantages and application as catalysts

With the pursuit of high-efficiency microwave absorbing materials (MAMs), biomass derived porous carbon (BPC)-based materials have attracted a great deal of attentions due to their plentiful resources, low density and highly environment-friendly. The microwave absorption of BPC composites is closely correlated to their composition, surface chemical activity, microstructures, and pore size, which are in turn decisively determined by the biomass precursors and subsequent carbonization or activation. In this article, we provide a timely and comprehensive review on recent achievements for the microwave absorption properties of various BPC-based MAMs. Firstly, the general synthesizing approaches for carbon materials from various biomass sources, especially in relation to the carbonization and activation are summarized. Then, based on the basic microwave absorption theory, the performances of pure BPC served as microwave absorber are presented. After that, the strategies to improve the microwave absorption properties of BPC including heteroatom doping and the formation of composites with magnetic metals, metal oxides, polymers, and so on, are discussed as well. Finally, we provide discussions and prospects for the development of BPC as lightweight and efficient MAMs in the further. It is believed that the current progress in experimental investigations combined with theoretical predictions will greatly promote the design and development of lightweight and efficient MAMs. Moreover, as an important type of MAMs, views on the challenges and prospects of BPC-based MAMs are proposed as well.

Biomass derived porous carbon (BPC) and their composites as lightweight and efficient microwave absorption materials

Valorization of levulinic acid over non-noble metal catalysts: challenges and opportunities

Currently, the development of alternative and green energy sources has been being strongly pushed aiming to recoup the lack of fossil energy, to meet the ever-increasing demand of energy use in modern society, and to palliate concerns regarding environmental pollution and global climate change. Therefore, producing energy from biomass sources has recently been of great interest because biomass is considered as a reliable and ubiquitous source. Indeed, the conversion of biomass into furan derivatives through the catalytic production process is emerging as a fascinating and promising method. Being one of the furan-based compounds, 2-Methylfuran (MF) is known as a critical platform substance and an ideal green solution on the pathway of finding alternative fuels because the MF properties are similar to those of fossil fuels and MF could be generated from renewable biomass source. In this review paper, the process of MF synthesis from biomass through catalyst reactions was thoroughly analyzed. More importantly, the pyrolysis and oxidation progress of MF was also critically presented aiming to clarify the applicability of MF to internal combustion engines. Finally, the performance, the characteristics of combustion, and pollutant formation of internal combustion engines fueled with MF were discussed in detail. In general, MF could become a promising alternative fuel for internal combustion engines although studies on the engine durability, compatibility to materials, tribology behaviors should be further carried out in the future.

2-Methylfuran (MF) as a potential biofuel: A thorough review on the production pathway from biomass, combustion progress, and application in engines

Facile assembly of Cu-Cu2O/N-reduced graphene oxide nanocomposites for efficient synthesis of 2-methylfuran

Continuous synthesis of ethyl levulinate over Cerium exchanged phosphotungstic acid anchored on commercially silica gel pellets catalyst

p-Toluenesulfonic acid doped polyaniline was developed as a catalyst for the production of biodiesel from waste cooking oil The physical and chemical properties of the obtained catalyst were characterized in detail It was found that the yield of fatty acid methylesters reached 971%, and the physical properties of the obtained biodiesel sample satisfied the requirement of ASTM D6751 standards In addition, the catalyst exhibited excellent stability for 10 runs Therefore, this heterogeneous catalyst has potential for biodiesel production from waste cooking oil, so further pilot tests deserve to be carried out and may be used in large-scale industries

Efficient biodiesel production from waste cooking oil using p-toluenesulfonic acid doped polyaniline as a catalyst

Cu-Zn/ZrO2 catalyst with an alumina binder was built for catalytic hydrogenation of ethyl levulinate to γ-valerolactone. N2 adsorption–desorption, X-ray powder diffraction, Fourier transform infrared spectroscopy, NH3 temperature-programmed desorption, H2 temperature-programmed reduction, and N2O decomposition were used to characterize the catalysts. The obtained results exhibited that porosity and acidity of the catalysts were strongly influenced by the binder; the most outstanding catalytic performance (96.4% ethyl levulinate conversion and 94.0% selectivity for γ-valerolactone) was observed on the catalyst with 20 wt % alumina binder for 30 h of time on stream. The good activity of this catalyst was due to its relatively good Cu species dispersion and proper acidity.

Xiangjin Kong

Papers

Facile assembly of Cu-Cu2O/N-reduced graphene oxide nanocomposites for efficient synthesis of 2-methylfuran

Continuous synthesis of ethyl levulinate over Cerium exchanged phosphotungstic acid anchored on commercially silica gel pellets catalyst

Efficient biodiesel production from waste cooking oil using p-toluenesulfonic acid doped polyaniline as a catalyst

Continuous Hydrogenation of Ethyl Levulinate to γ-Valerolactone over Cu-Zn/ZrO2 Catalyst with Alumina Binder

First principle calculations of electronic, band structural, and optical properties of BixSr1-xTiO3 perovskite