Graham Hutchings featured in Chemistry World

Catalysis Science & Technology Advisory Board member Graham Hutchings, from Cardiff University, has had his recent research highlighted in Chemistry World. His paper, published in Nature Chemistry, looks at improving the catalytic activity of gold nanoparticles, by removing the ligands used in the initial synthesis.

Read the Chemistry World article to find out more…

Interested in catalysis with gold? Upcoming Faraday Discussion 152 is focused on the precise nature of the catalysed reactions of gold, register now!!

Faraday Discussion 152: Gold – Last chance to register!

4 – 6 July 2011, Cardiff, UK

www.rsc.org/fd152

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Partially hydrolysed beta-glucan from yeast cells

In this recently published Catalysis Science & Technology article, Tatiana Felix Ferreira and colleagues from the Federal University of Rio de Janeiro extract beta-glucan from yeast cell walls.

Glucans are an important part of a good diet as they help keep the immune system healthy and are important in glycemia control. Glucans are a type of polysaccharide, and include substances like cellulose.

Ferreira’s team wanted to obtain partially hydrolysed beta-glucan as this is more easily absorbed by the digestive system. Read the full article to find out how they did this…

A new method to obtain β-glucan from Saccharomyces cerevisiae cells
Tatiana Felix Ferreira, Leonardo Rodrigues de Andrade, Maria Alice Zarur Coelho and Maria Helena Miguez da Rocha-Leão
Catal. Sci. Technol., 2011, DOI: 10.1039/C0CY00057D

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North American Catalysis Society meeting, Detroit

Dr Jamie Humphrey, Catalysis Science & Technology‘s Managing Editor, will be attending the North American Catalysis Society meeting next week in Detroit.

If you’d like to meet up with Jamie while he is there, please contact us.

To see which other conferences the team will be attending visit our earlier blog post…

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Hot Review Article: Photocatalysis with titania and niobium compounds

This Catalysis Science & Technology Hot article, reviews how photo-assisted selective NO reduction with ammonia over titania and the photooxidation of alcohols over Nb2O5 works.

Tetsuya Shishido and co-workers from Kyoto University summarise recent progress in investigating the reaction mechanism to explain this important photocatalytic effect.

Read the full review article for FREE to find out more…

A unique photo-activation mechanism by “in situ doping” for photo-assisted selective NO reduction with ammonia over TiO2 and photooxidation of alcohols over Nb2O5
Tetsuya Shishido, Kentaro Teramura and Tsunehiro Tanaka
Catal. Sci. Technol., 2011, DOI: 10.1039/C1CY00104C

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Photodegradation of phenols with ash-supported catalysts

Pollutants enter the ecosystem through several pathways. Dangerous substances are released into the atmosphere in many ways, for instance by car exhausts, from industrial fumes and drainage effluents and through degradation of pesticides to name but a few.

A contaminant that appears to be ubiquitous and released through all these pathways is phenol. Phenols are highly toxic by inhalation, causing lung edema, through ingestion, damaging kindneys, brain and liver, and it is also an extreme irritant to the skin, causing severe burns. Some phenols are reported carcinogens.

Degrading and removing phenols from contaminated water is essential before allowing it to enter the ecosystem. Many techniques have been developed and applied in order to do this, such as the use of polymeric resins, microbial or enzymatic  degradation, adsorption and other catalytic chemical transformations.

A recently published work by Yao, Shi and Sui focused on the latter.

The group focused on the use of supported titania for the photocatalytic degradation of phenols under UV light in aqueous solutions. The catalyst was prepared by anchoring TiO2 onto fly ash deriving from municipal waste combustion: a less usual support compared to the more widespread silica, alumina and zeolites.

The fly ash was treated with acid, washed  and dried before the titanium oxide coating was applied as a sol-gel and the material calcinated. Several calcination temperatures were tested, finding that 500 °C provided the ideal condition to obtain high degree of crystallinity in the catalyst.

The catalytic loading was also explored in the range 10-30 g/L to determine the highest concentration achievable without preventing light from reaching the bulk of the solution; the catalyst also proved robust and reusable, retaining 90% of its photocatalytic activity even after 4 cycles. Several tests were peformed to ensure that the activity of the system was due to the photocatalyst, including test runs with untreated  fly ash, only titania and UV irradiation alone.

To better understand the characteristics of the system, a kinetic study of the degradation reaction was also performed, revealing a first order-like behaviour; also, a three-step mechanism for the fly ash-supported catalyst was proposed.

Using the optimal conditions found during the study, the group achieved  94 % of phenol degradation with a catalyst loading of 20 g/L over 4 hours of irradiation, which, with its reusability, could make the catalyst potentially employable for continuous use in water treatment.

Read more about this catalyst here.

Application of fly ash supported titanium dioxide for phenol photodegradation in aqueous solution

Zhongliang Shi, Shuhua Yao and Chengcheng Sui
Catal. Sci. Technol., 2011, Advance Article
DOI: 10.1039/C1CY00019E

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HOT Article: Understanding enzymes that encourage probiotics

In this Catalysis Science & Technology Hot article, Francisco Maugeri Filho and co-workers from the State University of Campinas, Brazil examine the enzyme kinetics of fructosyltransferase.

Fructosyltransferase is extracted from Rhoduoturula, a strain of yeast found in flowers in the rainforests of Southern Brazil. It is used to catalyse the transformation of sucrose into fructooligosaccharides, which promote the growth of certain probiotics in the human digestive system.

In this paper the authors aim to describe a kinetic mathematical model for how the enzyme works, to help in the design of a fructooligosaccharide production bioreactor.

Read the full article for FREE to find out more about these enzymes…

Kinetic studies and modelling of the production of fructooligosaccharides by fructosyltransferase from Rhodotorula sp
Mónica B. Alvarado-Huallanco and Francisco Maugeri Filho
Catal. Sci. Technol., 2011, DOI: 10.1039/C0CY00059K

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Flattening catalysts

Hans Niemantsverdriet, Eindhoven University of Technology

In their recent Catalysis Science & Technology Perspective article, Hans Niemantsverdriet and colleagues look at how nanoparticle model systems on planar supports can be used to study changes under realistic reaction conditions. 

This work has allowed the group to gain insight into many aspects of catalysis – for example it provides a window into the mechanisms of catalyst regeneration. Read this Hot Article now to find out more about recent advances in studying catalyis using planar supports – FREE to read!

Studying Fischer–Tropsch catalysts using transmission electron microscopy and model systems of nanoparticles on planar supports
P. C. Thüne, C. J. Weststrate, P. Moodley, A. M. Saib, J. van de Loosdrecht, J. T. Miller and J. W. Niemantsverdriet
Catal. Sci. Technol., 2011, DOI: 10.1039/C1CY00056J

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Hot Article: Catalytic hexagonal nanoplates

In this Catalysis Science & Technology Hot Article, Miguel José-Yacamán at the University of Texas, San Antonio and colleagues from Portugal and Mexico investigated the synthesis and catalytic activity of molybdenum disulfide nanoplates.

The authors found that the optimum synthesis and annealing temperatures for producing the most hexagonal nanoplates with no impurities were 700 and 1000 °C respectively and the optimum reaction time was 2.5 hours.

The catalytic activity of the nanoparticles in the hydrodesulfurization of dibenzothiophene was tested and the activity was found to be comparable to, or higher than, other molybdenum disulfide-based catalysts. The nanoplates, however, showed greater selectivity for the biphenyl (desulfurization) product rather than the direct hydrogenation products preferred by the other catalysts.

Theoretical studies revealed that the rotated state of the catalyst, with a tendency to more metallic behavior, is favored, which could explain the improved catalytic activity of the nanoplates.

Read more for FREE until 15th June 2011:
Structure and catalytic properties of hexagonal molybdenum disulfide nanoplates
Carlos Fernando Castro-Guerrero, Francis Leonard Deepak, Arturo Ponce, Juan Cruz-Reyes, Mario Del Valle-Granados, Sergio Fuentes-Moyado, D. H. Galván and Miguel José-Yacamán
Catal. Sci. Technol., 2011, Advance Article
DOI: 10.1039/C1CY00055A, Paper

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Power from Fat

It is a fact that the world’s reservoirs of conventional oil are diminishing at a fast pace, forcing mankind to look for alternatives – possibly cleaner, sustainable and more environmentally friendly than fossil fuels.

While the technologies to exploit renewable sources of energy, like wind, tidal or solar power, mature to the point of replacing old-fashioned sources of energy, the use of sustainable fuels may bridge the gap between us and a greener future.

Biodiesel, a mixture of methyl esters of fatty acids, is an alternative to normal diesel that burns producing consistently less greenhouse gases and sulphurated compounds. Biodiesel can be produced via trans-esterification of vegetable or animal oils with methanol generally under acidic conditions; however, the process is as yet not cost-competitive with conventional diesel fuel.

A way to reduce costs is to use cheaper oils, containing free, unesterified fatty acids in the production process introducing an extra esterification step in the process.

Lingaiah et al., in a recently published paper, presented their work on a solid-phase catalyst for the acidic conversion of fatty acids into their correspondent methyl esters that simultaneously catalyses trans-esterification, avoiding the need for a separate reaction.

To provide the necessary acidity, the group employed 12-tungstophosphoric acid (TPA), a heteropolyacid, supported on tin oxide to increase its thermal stability and to reduce catalyst leakage in the reaction media. A full study of the effect of parameters like TPA loading, reaction temperature, stirring speed and catalyst concentration resulted in and optimised TPA loading of 15 wt%  to provide ideal surface area and acidity.

The activity test were performed using palmitic acid as the model substrate at 65 °C with a total catalyst loading of 25%, in the presence of an excess of methanol (1:14) to improve conversion (since the esterification is a reversible reaction). After 4 hours, the palmitic acid conversion reached exceeded 70%, and tests showed the catalyst could be washed and reused 5 times without significant loss of activity.

To prove its industrial viability, simultaneous esterification/trans-esterfication in the presence of mixtures of triglycerides and free fatty acids was successfully performed.

Read the full paper here.

Efficient solid acid catalysts for esterification of free fatty acids with methanol for the production of biodiesel
K. Srilatha, Ch. Ramesh Kumar, B. L. A. Prabhavathi Devi, R. B. N. Prasad, P. S. Sai Prasad and N. Lingaiah
Catal. Sci. Technol., 2011, Advance Article
DOI: 10.1039/C1CY00085C, Paper

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HOT Article: C-S cross-coupling using copper oxide nanopowder in ionic liquid

In this Catalysis Science & Technology Hot article, a recyclable copper nanopowder catalyst in ionic liquid is used to form a carbon-sulphur bond.

The formation of such bonds is important in organic chemistry, and various transition metal catalysed cross-coupling reactions have been investigated before, however this new method achieves excellent yields, is easily recyclable and easy to use.

This work is part of the authors research into organochalcogen derivatives for biological and asymmetric transformations.

Read the full article for FREE to find out more about C-S cross-coupling…

C–S cross-coupling of thiols with aryl iodides under ligand-free conditions using nano copper oxide as a recyclable catalyst in ionic liquid
Ricardo S. Schwab, Devender Singh, Eduardo E. Alberto, Paulo Piquini, Oscar E. D. Rodrigues and Antonio L. Braga
Catal. Sci. Technol., 2011, DOI: 10.1039/C1CY00091H

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