Biomass is an important feedstock for the renewable production of fuels, chemicals, and energy. As of 2005, over 3% of the total energy consumption in the United States was supplied by biomass, and it recently surpassed hydroelectric energy as the largest domestic source of renewable energy. Similarly, the European Union received 66.1% of its renewable energy from biomass, which thus surpassed the total combined contribution from hydropower, wind power, geothermal energy, and solar power. In addition to energy, the production of chemicals from biomass is also essential; indeed, the only renewable source of liquid transportation fuels is currently obtained from biomass.

The Catalytic Valorization of Lignin for the Production of Renewable Chemicals

and Fuels Changzhi Li,† Xiaochen Zhao,† Aiqin Wang,† George W. Huber,†,‡ and Tao Zhang*,† †State Key Laborotary of Catalysis, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China ‡Department of Chemical and Biological Engineering, University of WisconsinMadison, Madison, Wisconsin 53706, United States

Catalytic Transformation of Lignin for the Production of Chemicals and Fuels

The general principles of green chemistry guide the design of environmentally benign products and processes. It is known that the efficient utilization of carbon resources and carbon recycling are of great importance for the sustainable development of our society, and there are many related challenging scientific issues to be solved. Herein we attempt a holistic view on carbon resource processing, utilization, and recycling, and we call this “green carbon science”. We will discuss the definition and the four key principles of green carbon science and highlight some related fields including petroleum refining, the production of liquid fuels and chemicals from coal and methane, and transformations of CO2 and biomass into fuels and chemicals.

Green Carbon Science: Scientific Basis for Integrating Carbon Resource Processing, Utilization, and Recycling

An efficient organocatalytic method for chemoselective aerobic oxidation of secondary benzylic alcohols within lignin model compounds has been identified. Extension to selective oxidation in natural lignins has also been demonstrated. The optimal catalyst system consists of 4-acetamido-TEMPO (5 mol %; TEMPO = 2,2,6,6-tetramethylpiperidine-N-oxyl) in combination with HNO3 and HCl (10 mol % each). Preliminary studies highlight the prospect of combining this method with a subsequent oxidation step to achieve C–C bond cleavage.

http://pubs.acs.org/doi/pdf/10.1021/ja401793n

Chemoselective Metal-Free Aerobic Alcohol Oxidation in Lignin

The discovery of periodic mesoporous MCM-41 and related molecular sieves has attracted significant attention from a fundamental as well as applied perspective. They possess well-defined cylindrical/hexagonal mesopores with a simple geometry, tailored pore size, and reproducible surface properties. Hence, there is an ever-growing scientific interest in the challenges posed by their processing and characterization and by the refinement of various sorption models. Further, MCM-41-based materials are currently under intense investigation with respect to their utility as adsorbents, catalysts, supports, ion-exchangers, and molecular hosts. In this article, we provide a critical review of the developments in these areas with particular emphasis on adsorption characteristics, progress in controlling the pore sizes, and a comparison of pore size distributions using traditional and newer models. The model proposed by the authors for adsorption isotherms and criticalities in capillary condensation and hysteresis is found to explain unusual adsorption behavior in these materials while providing a convenient characterization tool.

Recent advances in processing and characterization of periodic mesoporous MCM-41 silicate molecular sieves

para-Selective t-butylation of phenol over mesoporous H-AlMCM-41

Nanosized metal oxides in the mesopores of MCM-41 and MCM-48 silicates

Trivalent-iron-substituted mesoporous molecular sieve catalysts (FeMCM-41) were synthesized hydrothermally and characterized systematically by various analytical and spectroscopic techniques. Temperature-programmed desorption studies of ammonia of the protonated catalyst (H–FeMCM-41) indicate a broad distribution of the acid sites. Vapour-phase alkylation of phenol with t-butyl alcohol (2-methyl-2-propanol) was carried out over this solid acid catalyst and p-t-butyl phenol was obtained as the major product with high selectivity.

Sushanta K. Badamali

Papers

para-Selective t-butylation of phenol over mesoporous H-AlMCM-41

Nanosized metal oxides in the mesopores of MCM-41 and MCM-48 silicates

Tertiary butylation of phenol over mesoporous H–FeMCM-41

Microwave assisted oxidation of a lignin model phenolic monomer using Co(salen)/SBA-15

The entrapment of UO22+ in mesoporous MCM-41 and MCM-48 molecular sieves