There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

This critical review provides a processing-structure-property perspective on recent advances in cellulose nanoparticles and composites produced from them. It summarizes cellulose nanoparticles in terms of particle morphology, crystal structure, and properties. Also described are the self-assembly and rheological properties of cellulose nanoparticle suspensions. The methodology of composite processing and resulting properties are fully covered, with an emphasis on neat and high fraction cellulose composites. Additionally, advances in predictive modeling from molecular dynamic simulations of crystalline cellulose to the continuum modeling of composites made with such particles are reviewed (392 references).

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Cellulose nanomaterials review: structure, properties and nanocomposites

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

Cellulases and related enzymes in biotechnology

We report the discovery of the hydrotropic properties of a recyclable aromatic acid, p-toluenesulfonic acid (p-TsOH), for potentially low-cost and efficient fractionation of wood through rapid and near-complete dissolution of lignin. Approximately 90% of poplar wood (NE222) lignin can be dissolved at 80°C in 20 min. Equivalent delignification using known hydrotropes, such as aromatic salts, can be achieved only at 150°C or higher for more than 10 hours or at 150°C for 2 hours with alkaline pulping. p-TsOH fractionated wood into two fractions: (i) a primarily cellulose-rich water-insoluble solid fraction that can be used for the production of high-value building blocks, such as dissolving pulp fibers, lignocellulosic nanomaterials, and/or sugars through subsequent enzymatic hydrolysis; and (ii) a spent acid liquor stream containing mainly dissolved lignin that can be easily precipitated as lignin nanoparticles by diluting the spent acid liquor to below the minimal hydrotrope concentration. Our nuclear magnetic resonance analyses of the dissolved lignin revealed that p-TsOH can depolymerize lignin via ether bond cleavage and can separate carbohydrate-free lignin from the wood. p-TsOH has a relatively low water solubility, which can facilitate efficient recovery using commercially proven crystallization technology by cooling the concentrated spent acid solution to ambient temperatures to achieve environmental sustainability through recycling of p-TsOH.

/pdf/rapid-and-near-complete-dissolution-of-wood-lignin-at-80-c-rf6fmgthlb.pdf

Rapid and near-complete dissolution of wood lignin at ≤80°C by a recyclable acid hydrotrope

Scots pine planks were heat‐treated under steam in a temperature range of 100–240°C at every 20°C. Changes in chemical structure of the wood samples were examined with UV resonance Raman (UVRR) and Fourier transform infrared (FT‐IR) spectroscopies. Prior to the FT‐IR and UVRR analysis, the heartwood part of wood samples were ground and extracted with acetone. Both the extracts and the extracted samples were analyzed. In addition, Klason lignin contents of the samples were determined. The FT‐IR and UVRR spectroscopy were powerful techniques to monitor chemical changes in the heat‐treated wood samples. Results confirmed most of what determined previously by other research groups using different techniques. The UVRR and FT‐IR spectra of acetone extracts showed that lignin became partly acetone soluble after a heat treatment of 180°C or greater. Increased levels of free phenolic hydroxyl groups were detected in lignin, probably due to cleavages of β‐O‐aryl ether interunit linkages. The amount of extr...

Thermal Modifications in Softwood Studied by FT‐IR and UV Resonance Raman Spectroscopies

Lors de la cuisson kraft, une grande partie des groupes acides 4-O-methylglycuroniques des xylanes du bois indigene est convertie en groupes d'acides 4-desoxyhex-4-enuroniques (HexA). Nous presentons ici une methode permettant l'extraction selective du HexA a l'aide d'une hydrolyse douce a l'acide des pâtes kraft. La quantite de HexA extraite etait en correlation lineaire avec une diminution de l'indice Kappa. Selon le type de pâte, l'indice Kappa a ete reduit de 2 a 7 unites. L'extraction du HexA a permis de reduire de facon significative la consommation de produits chimiques lors des sequences de blanchiment sans chlore elementaire et sans aucun chlore. La teneur en metal de transition dans les pâtes etait, apres traitement, aussi faible qu'apres un autre traitement avec des agents de complexion. L'hydrolyse selective n'a eu aucun effet marque sur les proprietes du papier des pâtes hautement blanchies, mais elle a ameliore de facon importante la stabilite de la blancheur des pâtes blanchies a l'oxygene et au peroxyde.

Selective hydrolysis of hexenuronic acid groups and its application in ECF and TCF bleaching of kraft pulps

Effect of cooking and bleaching on the structure of xylan in conventional pine kraft pulp

Characterisation of 4-deoxy-β-l-threo-hex-4-enopyranosyluronic acid attached to xylan in pine kraft pulp and pulping liquor by 1H and 13C NMR spectroscopy

Tapani Vuorinen

Papers

Rapid and near-complete dissolution of wood lignin at ≤80°C by a recyclable acid hydrotrope

Thermal Modifications in Softwood Studied by FT‐IR and UV Resonance Raman Spectroscopies

Selective hydrolysis of hexenuronic acid groups and its application in ECF and TCF bleaching of kraft pulps

Effect of cooking and bleaching on the structure of xylan in conventional pine kraft pulp

Characterisation of 4-deoxy-β-l-threo-hex-4-enopyranosyluronic acid attached to xylan in pine kraft pulp and pulping liquor by 1H and 13C NMR spectroscopy