Green Chemistry Blog

Utilization of renewable materials, such as carbon dioxide and cellulose, is a prevailing goal of green chemistry. Homogenous conditions promote the use of cellulose, but finding solvent systems that appreciably dissolve this robust polymer is a difficult task. Processing cellulose with minimal waste and economic cost are additional considerations, and existing methods warrant improvement in these regards. In another fashion, the utilization of carbon dioxide is dependent upon novel methods for capture and storage (CCS). Researchers at the Dalian National Laboratory for Clean Energy, China, have integrated the goals of CCS and cellulose dissolution in their latest research effort.

It is well known that mixtures of organic liquids, comprised of a strong base and an alcohol, form reversible ionic compounds upon the introduction of carbon dioxide. By using 1,1,3,3-tetramethyl guanidine in combination with dimethylsulfoxide (DMSO) and ethylene glycol, in particular, they observed microcrystalline cellulose dissolution of up to 10 wt% under mild conditions. The presence of the co-solvent DMSO was integral to achieve this extent of dissolution, and cellulose regeneration and recovery could be accomplished by several methods.

Learn more about their exciting results here:

Capturing CO₂ for cellulose dissolution
Haibo Xie, Xue Yu, Yunlong Yang, and Zongbao Kent Zhao
Green Chem., 2014, Advance Article, DOI: 10.1039/C3GC42395F 
 

Jenna Flogeras obtained her B.Sc. and M.Sc. in Chemistry from the University of New Brunswick (Fredericton), Canada. She is currently working towards her Ph.D. at Memorial University of Newfoundland, under the supervision of Dr. Francesca Kerton. Her research is focused on the synthesis of biodegradable polymers using main-group metal complexes as catalysts.

Here are the latest hot papers published in Green Chemistry, as recommended by the referees:

Physical properties and hydrolytic degradability of polyethylene-like polyacetals and polycarbonates
Patrick Ortmann, Ilona Heckler and Stefan Mecking  
Green Chem., 2014, Advance Article, DOI: 10.1039/C3GC42592D

Efficient chemical fixation of CO2 promoted by a bifunctional Ag2WO4/Ph3P system
Qing-Wen Song, Bing Yu, Xue-Dong Li, Ran Ma, Zhen-Feng Diao, Rong-Guan Li, Wei Li and Liang-Nian He 
Green Chem., 2014,16, 1633-1638, DOI: 10.1039/C3GC42406E

Water at elevated temperatures (WET): reactant, catalyst, and solvent in the selective hydrolysis of protecting groups
Wilmarie Medina-Ramos, Mike A. Mojica, Elizabeth D. Cope, Ryan J. Hart, Pamela Pollet, Charles A. Eckert and Charles L. Liotta  
Green Chem., 2014, Advance Article. DOI: 10.1039/C3GC42569J

All the papers listed above are free to access for the next 4 weeks!

Research by French scientists has identified 18 vanillin derived chemicals for application in the synthesis of bio-based polymers. Vanillin is interesting as a chemical intermediate because of its different functional groups, and because it is manufactured in different ways. Extraction of natural vanillin and fermentation of bio-based ferulic acid are high cost options compared to the petroleum derived synthesis from guaiacol. An alternative route to vanillin has recently been proposed starting from p-cresol, but this approach is also based on non-renewable feedstocks. Another procedure that presently has a minority share of global vanillin production is the valorisation of lignin. This process had fallen out of favour somewhat, but cleaner technologies have revitalised research into vanillin derived from Kraft lignin, benefiting from the growing interest in producing chemicals from lignin more generally.

Polymers of vanillin are known, but are not often significantly diversified from the parent molecule. This latest work lead by Sylvain Caillol has resulted in the synthesis of difunctionalised epoxides, carbonates, alkenes, alcohols, amines and carboxylic acids, all with obvious potential as monomers for bio-based polymers. Different polymer types have been targeted, including epoxy resins, polyesters and polyurethanes. Through this research a number of opportunities for new and interesting renewable polymers have been opened up, which utilise the abundant resource of lignin via the important chemical intermediate vanillin.

Vanillin, a promising biobased building-block for monomer synthesis
Maxence Fache, Emilie Darroman, Vincent Besse, Auvergne Rémi, Sylvain Caillol and Bernard Boutevin
Green Chem., 2014, Advance Article, DOI: 10.1039/C3GC42613K

Shrimp shells that would otherwise be thrown away by the seafood industry have been turned into tough fibres that can harvest valuable metals from water.

Robin Rogers, and his team at the University of Alabama in the US, had long been interested in using ionic liquids to process cellulose but the Deepwater Horizon oil spill in 2010 encouraged them to try something similar with chitin, the structural biopolymer that makes up the shells of various crustaceans. ‘We started working with the Gulf Coast Agricultural and Seafood Co-Op in Bayou La Batre, looking at uses for their shrimp shell waste, about the same time as the moratoriums on shrimping. It was quite clear that new products and profits were needed.’

Read the full article in Chemistry World»

Read the original journal article in Green Chemistry – it’s free to access until 9th April:
Surface modification of ionic liquid-spun chitin fibers for the extraction of uranium from seawater: seeking the strength of chitin and the chemical functionality of chitosan
Patrick S. Barber, Steven P. Kelley, Chris S. Griggs, Sergei Wallace and Robin D. Rogers  
Green Chem., 2014, Advance Article, DOI: 10.1039/C4GC00092G, Paper

Here are the latest hot papers in Green Chemistry, as recommended by the referees:

A continuous process for glyoxal valorisation using tailored Lewis-acid zeolite catalysts
Pierre Y. Dapsens, Cecilia Mondelli, Bright T. Kusema, René Verel and Javier Pérez-Ramírez  
Green Chem., 2014, Advance Article, DOI: 10.1039/C3GC42353K, Paper

Solvents for sustainable chemical processes
Pamela Pollet, Evan A. Davey, Esteban E. Ureña-Benavides, Charles A. Eckert and Charles L. Liotta  
Green Chem., 2014, Advance Article, DOI: 10.1039/C3GC42302F, Critical Review

Branched polyethylene mimicry by metathesis copolymerization of fatty acid-based α,ω-dienes
Thomas Lebarbé, Mehdi Neqal, Etienne Grau, Carine Alfos and Henri Cramail  
Green Chem., 2014, Advance Article, DOI: 10.1039/C3GC42280A, Communication

All the papers listed above are free to access for the next 4 weeks!

A biotechnological process to transform lignin into an adhesive opens the door on an eco-friendly strategy for recycling carpets, new research shows.

Traditional carpets consist of yarns stuck to a backing fabric by an adhesive – usually synthetic latex. As part of the production process, the latex is cured at high temperatures, but this creates a non-recyclable material as the latex is almost impossible to remove at the end of a carpet’s life. As a result, almost all carpets are disposed of by burning in an incinerator.

With a view to finding a more environmentally friendly solution to carpet disposal, Tzanko Tzanov and his team at the Polytechnic University of Catalonia in Barcelona, Spain, decided to replace the synthetic latex with an organic lignin-based adhesive to produce a renewable woollen floor covering.

Lignin is an aromatic polymer that reinforces cellulose fibres in plants and is readily available as a waste product of paper and biofuel production. 

It can be easily converted into an adhesive using laccase, an enzyme found in plants and fungi. ‘Lignin is transformed by an oxidative enzymatic process that activates the phenolic structures, which can then react chemically with the wool fibres and bind them to the backing,’ explains Tzanov. The process is carried out at much lower temperatures than in latex production – around 50°C rather than 150°C – making it much more environmentally friendly.

The carpets can degrade and be recycled as a soil fertiliser

The laccase enzymes that convert lignin into an adhesive are also involved in its biodegradation, meaning that the carpets can be recycled at the end of their usable life. Instead of being incinerated, the carpets are shredded and returned to nature, where they degrade and can be used as a soil fertiliser.

Diego Moldes Moreira, an expert in natural products and bioprocesses at the University of Vigo in Spain is impressed by the innovative and sustainable solution. ‘We could expect to find the proposed biotech carpets in stores in the short–medium term,’ he says. In fact, Tzanov’s team are already working with Dutch companies, James and Best Wool Carpets, on an industrial scale-up.

You can also read this article in Chemistry World»

Read the original journal article in Green Chemistry – it’s free to access until 27th March:
An enzymatic approach to develop a lignin-based adhesive for wool floor coverings
Elisabetta Aracri, Carlos Díaz Blanco and Tzanko Tzanov  
Green Chem., 2014, Accepted Manuscript, DOI: 10.1039/C4GC00063C, Paper