Archive for the ‘Hot Article’ Category

Developments in the offshore seaweed feedstock bio-refinery model

Graphical abstract green chem algae biorefineryThe land use issues associated with biomass production points to marine biomass as a promising alternative. Seaweed is a rich resource, abundant in the world’s oceans. In addition to its potential for biofuel production, it is also important to obtain a stream of renewable chemicals from any seaweed bio-refinery to create an economically viable and sustainable process.

The present development, led by an Indian research team prominent in this field, creates a valuable side stream of chemical products to supplement the production of bio-ethanol from cellulose. Lipids, pigments and agar are all obtainable from the red algae feedstock by way of sequential extraction processes that improves the quality of the agar produced and significantly reduces the amount of auxiliary chemicals required compared to previous methods.

Read the advanced article in Green Chemistry online now:

R. S. Baghel, N. Trivedi, V. Gupta, A. Neori, C. R. K. Reddy, A. Lali and B. Jha

Green Chem., 2015, Advance Article. DOI: 10.1039/C4GC02532F

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Thin film approach to biocatalysis

This lipase is one of the most largely employed enzymes in industry © Valerio Ferrario

Taking an unconventional approach to biocatalysis has allowed scientists in Italy to improve enzyme recyclability with a solvent-free reaction mixture. And by emphasising a need to design processes, biocatalysts and reactors together, instead of separately, they hope to widen the industrial applications of nature’s catalysts.

Lucia Gardossi, from the University of Trieste in Italy, has been investigating solvent-free reaction mixtures, which appeal to industry because of their comparably small production volumes and lack of organic solvents to dispose of. Although their efficiency and selectivity are attractive, biocatalysed versions of industrial reactions are rarely economically viable. The typically viscous reaction mixtures require vigorous mixing, which damages the enzymes and limits their recyclability.

For the full story from Debbie, make sure to take a look at the page on Chemistry World!

This original research article is free to access unitl 11 March 2015. Download it here:

A Pellis et al, Green Chem., 2015, DOI: 10.1039/c4gc02289k

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Mild synthesis of alkaloids using chemoenzymatic cascades

One pot enzymatic catalysis for the synthesis of chiral alkaloidsOpen access communication: One-pot triangular chemoenzymatic cascades for the synthesis of chiral alkaloids from dopamine

Researchers at UCL, UK, have developed a novel use of one-pot, multi-step enzymatic catalysis for the synthesis of chiral alkaloids. Transaminase (TAm) and norcoclaurine synthase (NCS) were employed as catalysts. In the synthesis of the tetrahydroprotoberberine product two carbon-carbon bonds are created under mild conditions with good enantiomeric purity (ee >95%), all in a short duration (3.5 hours).

The successive Pictet-Spengler cyclisation reactions provide an atom economic approach and high enantioselectivity to the formation of this valuable class of products. The authors of this work recognise the “remarkable potential of in vitro biocatalysis for the formation of complex chiral compounds“, which is increasingly important to contemporary green chemistry.

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

One-pot triangular chemoenzymatic cascades for the synthesis of chiral alkaloids from dopamine

B. R. Lichman, E. D. Lamming, T. Pesnot, J. M. Smith, H. C. Hailes and J. M. Ward

Green Chem., 2015, Advance Article. DOI: 10.1039/C4GC02325K

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Versatile chemical intermediate produced renewably using heterogeneous catalyst

Bio-based acetaldehyde graphical abstractEfficient and selective conversion of lactic acid into acetaldehyde using a mesoporous aluminum phosphate catalyst

Acetaldehyde is needed by the chemical industry for many diverse applications, such as paint and cosmetic formulations, plastics and construction materials. As such there is a need for renewable acetaldehyde within the bio-based economy and bio-ethanol can be oxidised to give acetaldehyde for this purpose. Now an alternative process using lactic acid as a feedstock has been developed.

The catalyst for this transformation is a mesoporous aluminium phosphate, facilitating full conversion of the lactic acid and yields of acetaldehyde exceeding 90%. While the use of aluminium is very favourable compared to ethylene oxidation catalysts based on silver for example, the longevity of phosphorus reserves are a concern. However the catalyst is robust and can be used for over 200 hours. Also, the process is efficient at lower temperatures than are often needed for transformations of lactic acid.

Read the advanced article in Green Chemistry online now:

Efficient and selective conversion of lactic acid into acetaldehyde using a mesoporous aluminum phosphate catalyst

Congming Tang, Jiansheng Peng, Xinli Li, Zhanjie Zhai, Wei Bai, Ning Jiang, Hejun Gao and Yunwen Liao

Green Chem., 2015, Advance Article. DOI: 10.1039/C4GC01779J

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Recent HOT GC Articles

Check out the following HOT articles, these have all been made free to access for a limited time:
Chemical conversion pathways for carbohydrates
Chandrani Chatterjee, Frances Pong and Ayusman Sen
Green Chem., 2015, Advance Article
DOI: 10.1039/C4GC01062K

Catalytic conversion of carbohydrate-derived oxygenates over HZSM-5 in a tandem micro-reactor system
Kaige Wang, Jing Zhang, Brent H. Shanks and Robert C. Brown
Green Chem., 2015, Advance Article
DOI: 10.1039/C4GC01784F

Upgrading biomass-derived furans via acid-catalysis/hydrogenation: the remarkable difference between water and methanol as the solvent
Xun Hu, Roel J. M. Westerhof, Liping Wu, Dehua Dong and Chun-Zhu Li
Green Chem., 2015, Advance Article
DOI: 10.1039/C4GC01826E

Recent progress on supported polyoxometalates for biodiesel synthesis via esterification and transesterification
Nilesh Narkhede, Sukriti Singh and Anjali Patel
Green Chem., 2015, Advance Article
DOI: 10.1039/C4GC01743A

A novel D-glucosamine-derived pyridyl-triazole@palladium catalyst for solvent-free Mizoroki–Heck reactions and its application in the synthesis of Axitinib
Chao Shen, Hongyun Shen, Ming Yang,Chengcai Xia and Pengfei Zhang
Green Chem., 2015, Advance Article
DOI: 10.1039/C4GC01606H  

Aqueous ionic liquid solutions as alternatives for sulphide-free leather processing
R. Vijayaraghavan, N. Vedaraman, C. Muralidharan, A. B. Mandal and D. R. MacFarlane
Green Chem., 2015, Advance Article
DOI: 10.1039/C4GC01476F

Si-mediated fabrication of reduced graphene oxide and its hybrids for electrode materials
Barun Kumar Barman and Karuna Kar Nanda
Green Chem., 2015, Advance Article
DOI: 10.1039/C4GC01485E

Conversion of biomass derived valerolactone into high octane number gasoline with an ionic liquid
Jiayu Xin, Dongxia Yan, Olubunmi Ayodele, Zhan Zhang, Xingmei Lu and Suojiang Zhang
Green Chem., 2015, Advance Article
DOI: 10.1039/C4GC01792G

Ionic liquids: not always innocent solvents for cellulose
Matthew T. Clough, Karolin Geyer, Patricia A. Hunt, Sunghee Son, Uwe Vagt and Tom Welton
Green Chem., 2015, Advance Article
DOI: 10.1039/C4GC01955E

Electrocatalytic upgrading of model lignin monomers with earth abundant metal electrodes
Chun Ho Lam, Christy B. Lowe, Zhenglong Li, Kelsey N. Longe, Jordan T. Rayburn, Michael A. Caldwell, Carly E. Houdek, Jack B. Maguire, Christopher M. Saffron, Dennis J. Miller and James E. Jackson
Green Chem., 2015, Advance Article
DOI: 10.1039/C4GC01632G

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Lignin boosts sunscreen performance

Scientists in Canada and China have shown that the effectiveness of commercial sunscreens can be enhanced by the addition of lignin and, as an unprecedented bonus; sunlight exposure may help them work even better!

To read the full article written about this work visit Chemistry World.

The original research article is free to access until 14 November 2014.

Download it here: Y Qian, X Qiu and S Zhu, Green Chem., 2014, DOI: 10.1039/c4gc01333f

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Dissolving lignin

The separation of lignocellulosic biomass into its three component polymers; cellulose, hemicellulose, and lignin, is an important field of research relevant to biorefineries and the production of bio-based products. The chemical valorisation of polysaccaharides (to bio-ethanol for example) and the paper industries leave the lignin behind as waste.

Rich in aromatic functionality, it is unfortunate that because of the poor solubility of lignin up to 40% of lignocellulosic biomass feedstock is consigned to low value applications.Graphical abstract ammonia lignin

The use of ammonia as a solvent for lignin has now been revisited by a team of Dutch scientists in order to resolve this solubilisation bottleneck. Ammonia was shown to readily dissolve most varieties of lignin at room temperature and 7-11 bar, and can be removed simply by releasing the pressure.

The mild conditions make ammonia an attractive solvent for biorefineries looking to maximise lignocellulosic biomass utilisation. Furthermore the necessary apparatus is already incorporated into biorefineries for the ammonia fibre explosion (AFEX) process.

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

Lignin solubilisation and gentle fractionation in liquid ammonia

Zea Strassberger, Pepijn Prinsen, Frits van der Klis, Daan S. van Es, Stefania Tanasea and Gadi Rothenberg

Green Chem., 2014, Advance Article. DOI: 10.1039/C4GC01143K

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Alane without aluminum byproduct

pXRD alane synthesis under hydrogenResearchers from Iowa State University have recently developed a route to non-solvated aluminum trihydride (alane), free of metallic aluminum. The reaction occurs at room temperature by the mechanical milling of lithium aluminum hydride and aluminum chloride and a nearly complete conversion can be achieved in 30–60 mins. The formation of aluminum can be entirely avoided above a certain critical pressure, which depends on the nature of the gas and the milling parameters. An intermediate was identified in the process, which reacts to produce alane and lithium chloride.

Due to the impractical conditions required for the direct hydrogenation of aluminum, alternative routes that allow for the large-scale preparation of alane are essential, for example the one described in this paper. The authors have also recently introduced a mechanochemical synthesis of alane using lithium hydride as a starting material, which directly leads to adduct-free alane.

Check out the original article online now:

Solvent-free mechanochemical synthesis of alane, AlH3: effect of pressure on the reaction pathway
S. Gupta, T. Kobayashi, I. Z. Hlova, J. F. Goldston, M. Pruski, and V. K. Pecharsky
Green Chem. 2014, 16, 4378.
DOI: 10.1039/C4GC00998C

Jenna Flogeras obtained her B.Sc. and M.Sc. in Chemistry from the University of New Brunswick (Fredericton), Canada. She is currently a Ph.D. student at Memorial University in Newfoundland, where she studies aluminum-based catalysts under the supervision of Dr. Francesca Kerton.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

A graphene photocatalysed synthesis of chiral alcohols

The asymmetric, enzymatic reduction of ketones has been enhanced with a graphene derived light harvesting photocatalyst. Typically the use of reducing enzymes for specialty chemical synthesis is restricted by the cost of the redox cofactor. In this example the enzyme cofactor is recycled via a rhodium complex. The energy needed to do this is delivered by the chlorophyll mimicking graphene. Enantioselectivity to the resulting alcohols is high, and applicable to both aliphatic and aromatic ketones.

Graphene photocatalysis bio-catalysis chiral alcohols

The scientists from KRICT responsible for this research believe that artificial photosynthesis using functionalised graphene shows promise for energy generation and sustainable chemical production in the near future, with applications including carbon dioxide sequestering reactions already proven as viable.

Check out the full article – online now!

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Plant plastics reach for the stars – Green Chemistry article in Chemistry World

Aminoethoxy ethanol substituted phosphazene

Virginia Nykänen and colleagues at Aalto University, Finland have transformed rice starch into a temporally stable, optically transparent, biodegradable plastic with a high degree of mechanical strength and good thermal resistance.

This important step towards bioplastics made from simple and sustainable resources has potential applications in food packaging and biomedical materials.

Read the full article here in Chemistry World.

This paper is free to access until 8 September, so download it now:

V P S Nykänen et al, Green Chemistry, 2014, DOI: 10.1039/c4gc00794h

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)