Green Chemistry Blog

Japanese scientists have discovered a method to convert tree hemicellulose (xylan) in a tunable fashion to either one of three chemical product streams, depending on the combination of catalysts and solvent phases employed. Hemicellulose is 20-30% of the structural lignocellulose component of biomass, with cellulose (40-50%) and lignin (20-30%) accounting for the remainder. As part of a biorefinery, it is important to be able to advantageously develop all of the feedstock into products in order to reduce waste and value the economic and material investment made during biomass production.

First, rhenium was introduced into an iridium impregnated silica. The resulting catalyst was capable of producing xylitol from xylan (79% yield) if used in combination with sulphuric acid in an aqueous reaction. Some success in achieving a partial reduction to pentanol was then observed when an organic solvent was introduced to the reaction. Finally, full hydrogenolysis to give pentane (in 70% yield) was accomplished by adding a HZSM-5 zeolite to the biphasic reaction.

The heterogeneous catalyst is recoverable and can be reactivated to continue providing a good yield of pentane. Thus a new flexibility to woody biomass processing has been demonstrated, complementing the more prevalent studies on cellulose and lignin.

This work is included in a online collection showcasing work presented at the 3rd International Symposium on Green Chemistry held in La Rochelle, France on 3rd-7th May 2015. Access the full collection of articles here.

Selective transformation of hemicellulose (xylan) into n-pentane, pentanols or xylitol over a rhenium-modified iridium catalyst combined with acids
Sibao Liu, Yasuyo Okuyama, Masazumi Tamura, Yoshinao Nakagawa, Akio Imai and Keiichi Tomishige
Green Chem., 2016, Advance Article. DOI: 10.1039/C5GC02183A

The following HOT articles have been highlighted by the reviewers of the articles as being particularly interesting or significant pieces of research. These are all free to access until 30/11/2015. The order they appear in the list has no meaning or ranking.

Zinc(II)-catalyzed reactions of carbon dioxide and propargylic alcohols to carbonates at room temperature
Jiayin Hu, Jun Ma, Qinggong Zhu, Qingli Qian, Hongling Han, Qingqing Mei and Buxing Han
Green Chem., 2015, Advance Article
DOI: 10.1039/C5GC01870F, Communication

Synthesis of a polyisobutylene-tagged fac-Ir(ppy)3 complex and its application as recyclable visible-light photocatalyst in a continuous flow process
Daniel Rackl, Peter Kreitmeier and Oliver Reiser
Journal Article
Green Chem., 2015, Advance Article
DOI: 10.1039/C5GC01792K, Paper

Precise oxygen scission of lignin derived aryl ethers to quantitatively produce aromatic hydrocarbons in water
Zhicheng Luo, Yimeng Wang, Mingyuan He and Chen Zhao
Journal Article
Green Chem., 2015, Advance Article
DOI: 10.1039/C5GC01790D, Paper

Selective hydrogenation of levulinic acid to 1,4-pentanediol in water using a hydroxyapatite-supported Pt–Mo bimetallic catalyst
T. Mizugaki, Y. Nagatsu, K. Togo, Z. Maeno, T. Mitsudome, K. Jitsukawa and K. Kaneda
Journal Article
Green Chem., 2015, Advance Article
DOI: 10.1039/C5GC01878A, Communication

Oxidative desulfurization of DBT with H2O2 catalysed by TiO2/porous glass
C. Shen, Y. J. Wang, J. H. Xu and G. S. Luo
Journal Article
Green Chem., 2015, Advance Article
DOI: 10.1039/C5GC01653C, Paper

Cooperative catalysis of Pt/C and acid resin for the production of 2,5-dimethyltetrahydrofuran from biomass derived 2,5-hexanedione under mild conditions
Huacong Zhou, Jinliang Song, Qinglei Meng, Zhenhong He, Zhiwei Jiang, Baowen Zhou, Huizhen Liu and Buxing Han
Journal Article
Green Chem., 2015, Advance Article
DOI: 10.1039/C5GC01741F, Paper

Supported nano-gold-catalyzed N-formylation of amines with paraformaldehyde in water under ambient conditions
Zhengang Ke, Yan Zhang, Xinjiang Cui and Feng Shi
Journal Article
Green Chem., 2015, Advance Article
DOI: 10.1039/C5GC01992C, Paper

Efficient pyrido[1,2-a]benzimidazole formation from 2-aminopyridines and cyclohexanones under metal-free conditions
Yanjun Xie, Jun Wu, Xingzong Che, Ya Chen, Huawen Huang and Guo-Jun Deng
Journal Article
Green Chem., 2015, Advance Article
DOI: 10.1039/C5GC01978H, Communication

Antimony recovery from the halophosphate fraction in lamp phosphor waste: a zero-waste approach
David Dupont and Koen Binnemans
Journal Article
Green Chem., 2015, Advance Article
DOI: 10.1039/C5GC01746G, Paper

An efficient and recyclable tetraoxo-coordinated zinc catalyst for the cycloaddition of epoxides with carbon dioxide at atmospheric pressure
Ran Ma, Liang-Nian He and Yue-Biao Zhou
Journal Article
Green Chem., 2015, Advance Article
DOI: 10.1039/C5GC01826A, Paper

Production of solubilized carbohydrate from cellulose using non-catalytic, supercritical depolymerization in polar aprotic solvents
Arpa Ghosh, Robert C. Brown and Xianglan Bai
Journal Article
Green Chem., 2015, Advance Article
DOI: 10.1039/C5GC02071A, Paper

Attractive aerobic access to the α,β-unsaturated acyl azolium intermediate: oxidative NHC catalysis via multistep electron transfer
L. Ta, A. Axelsson and H. Sundén
Journal Article
Green Chem., 2015, Advance Article
DOI: 10.1039/C5GC01965F, Communication

Catalyst-free dehydrative SN1-type reaction of indolyl alcohols with diverse nucleophiles “on water”
Jian Xiao, Hao Wen, Liang Wang, Lubin Xu, Zhihui Hao, Chang-Lun Shao and Chang-Yun Wang
Journal Article
Green Chem., 2015, Advance Article
DOI: 10.1039/C5GC01838B, Paper

Towards sustainable fuels and chemicals through the electrochemical reduction of CO2: lessons from water electrolysis
Antonio J. Martín, Gastón O. Larrazábal and Javier Pérez-Ramírez
Journal Article
Green Chem., 2015, Advance Article
DOI: 10.1039/C5GC01893E, Perspective

Light driven styrene epoxidation and hydrogen generation using H2O as an oxygen source in a photoelectrosynthesis cell
P. Farràs, C. Di Giovanni, J. N. Clifford, P. Garrido-Barros, E. Palomares and A. Llobet
Journal Article
Green Chem., 2015, Advance Article
DOI: 10.1039/C5GC01589H, Paper

Synthesis of Ni-based co-catalyst functionalized W:BiVO4 nanofibers for solar water oxidation
Ki Ro Yoon, Jong Wan Ko, Doo-Young Youn, Chan Beum Park and Il-Doo Kim
Journal Article
Green Chem., 2015, Advance Article
DOI: 10.1039/C5GC01588J, Communication

Biomass-derived binderless fibrous carbon electrodes for ultrafast energy storage
R. Berenguer, F. J. García-Mateos, R. Ruiz-Rosas, D. Cazorla-Amorós, E. Morallón, J. Rodríguez-Mirasol and T. Cordero
Journal Article
Green Chem., 2015, Advance Article
DOI: 10.1039/C5GC02409A, Paper

Membrane technology is a major contributor to present day desalination and other water purification processes. Ironically, the benefits to water quality that membranes provide are counteracted by the actual membrane fabrication procedure, which collectively emits billions of litres of wastewater, contaminated with reprotoxic organic solvents, every year. Only 31% of membrane manufacturing companies surveyed treat the waste water, either themselves or using a waste management company. The rest dispose of this contaminated water down the sink.

This study, carried out by researchers at the University of Manchester, UK, sought to identify reusable absorbents for the purpose of purifying the aqueous wastestreams from membrane production. Several absorbents were found to be suitable for extracting DMF and NMP from wastewater. These include imprinted polymers, zeolites, and graphene based materials, all of which can be regenerated and reused. The purified waste water could also be reused in the membrane fabrication process, vastly reducing water use.

This article is open access and available to everyone to read for free:

Sustainable wastewater treatment and recycling in membrane manufacturing

Razali et al., Green Chem., 2015, advanced article. DOI: 10.1039/c5gc01937k

A new study comparing life cycle assessments has shown that changing from a fossil derived feedstock to biomass is not necessarily beneficial to the environment. A reliance on food crops and inefficient conversion into chemical products will cause impact the environmental and result in an expensive product, also limiting its commercial opportunities.

Taking the example of hexamethylenediamine, the precursor to nylon-66, scientists based at Solvay in China have shown that the benefit of adopting a renewable feedstock (starch, in this instance) is counteracted by eutrophication concerns and greenhouse gas emissions. The issue largely stems from the cultivation of the biomass and the energy required to process the starch into chemical intermediates. The renewable route requires several high energy transformations to remove the original functionality of the biomass and obtain the conventional nylon monomer.

One lesson to be taken from this study is to give greater consideration to novel bio-based polymers that can be produced advantageously from bio-based feedstocks. Ideally, these would include wastes and agricultural by-products, thus making use of the reactive chemical groups inherent to the biomass rather than removing them.

Hexamethylenediamine (HMDA) from Fossil vs. Bio-based Routes: An Economic and Life Cycle Assessment Comparative Study

A. B. Dros et al., Green Chem., 2015, advanced article. DOI: 10.1039/C5GC01549A

The following HOT articles have been highlighted by the reviewers of the articles as being particularly interesting or significant pieces of research. These are all free to access until 30/09/2015. The order they appear in the list has no meaning or ranking.

Tandem Lewis/Brønsted homogeneous acid catalysis: conversion of glucose to 5-hydoxymethylfurfural in an aqueous chromium(III) chloride and hydrochloric acid solution
T. Dallas Swift, Hannah Nguyen, Andrzej Anderko, Vladimiros Nikolakis and Dionisios G. Vlachos
Journal Article
DOI: 10.1039/C5GC01257K, Paper

Expanding the scope of biogenic substrates for the selective production of formic acid from water-insoluble and wet waste biomass
Jakob Albert and Peter Wasserscheid
Journal Article
DOI: 10.1039/C5GC01474C, Paper

Hybrid bipolar membrane electrodialysis/ultrafiltration technology assisted by a pulsed electric field for casein production
Sergey Mikhaylin, Victor Nikonenko, Gérald Pourcelly and Laurent Bazinet
Journal Article
DOI: 10.1039/C5GC00970G, Paper

Solvent free depolymerization of Kraft lignin to alkyl-phenolics using supported NiMo and CoMo catalysts
Chowdari Ramesh Kumar, Narani Anand, Arjan Kloekhorst, Catia Cannilla, Giuseppe Bonura, Francesco Frusteri, Katalin Barta and Hero Jan Heeres
Journal Article
DOI: 10.1039/C5GC01641J, Paper
From themed collection Lignin chemistry and valorisation

An interchangeable homogeneous ⇔ heterogeneous catalyst system for furfural upgrading
Lu Wang and Eugene Y.-X. Chen
Journal Article
DOI: 10.1039/C5GC01648G, Communication