Archive for the ‘Heterogeneous catalysis’ Category

8th International Symposium on Carbon for Catalysis, CarboCat–VIII

The Carbon Group of the Portuguese Chemical Society (C@SPQ) cordially invites you to attend the 8th International Symposium on Carbon for Catalysis, CarboCat–VIII, that will take place in Porto, Portugal, on June 26 – 29, 2018.

Following the previous CarboCat meetings held in Lausanne (2004), Saint-Petersburg (2006), Berlin (2008), Dalian (2010), Brixen (2012), Trondheim (2014) and Strasbourg (2016), CarboCat-VIII will be devoted to new developments and fundamental advances on carbon materials (conventional and nanostructured carbons) for catalytic applications.

Catalysis Science & Technology together with Energy & Environmental Science, Materials Horizons and Journal of Materials Chemistry A are delighted to be supporting the event.

Register now!

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FineCat 2017: Great symposium at Royal Palace

Jointly organized by Italy’s Research Council and Palermo’s University, the 6th edition of the “FineCat – Symposium on heterogeneous catalysis for fine chemicals” was held in Sicily’s Royal Palace in Palermo on April 5th.

Gideon Grader at FineCat017 (Palermo, 5 April 2017)The scientific works (watch the video) were opened by Professor Gideon Grader, a Professor of chemical engineering at Haifa’s Technion where he leads the University’s energy program.

In an inspirational lecture Professor Grader discussed the mechanisms discovered by his group to create the unique mesoporous core-shell architecture of nanostructured materials with multifunctional, specific properties – an highly desirable finding which facilitates new possibilities and applications in all fields of catalysis due to the combination of high surface to volume ratio and low mass transfer resistance to and from the catalytic sites.

Heidelberg University’s organic chemistry Professor A. Stephen K. Hashmi, gave a fascinating lecture on new aspects of gold catalysis applied to the synthesis of a variety of functional products. Professor Hashmi described the latest findings concerning the new synthetic methods to access both gold(I) and gold(III) catalytic species, the identification of highly reactive catalysts, and the development of gold-catalyzed reactions including additions to allenes and alkenes, benzannulations, cycloisomerization, rearrangement as well as oxidation and reduction reactions.

Already used for the production of bulk chemicals, gold catalysis is poised to be introduced in the production of the basic ingredients of a wide variety of valued added products ranging from pharmaceuticals through liquid crystals and organic light emitting diodes (OLED) for computer, TV and mobile phone screens.

Raed Abu-REziq at FineCat017 (Palermo, 5 April 2017)Professor Raed Abu-Reziq, of the Hebrew University of Jerusalem, Israel, presented the results of his team concerning the development of new nanostructured materials, nano- and microreactors as platforms for heterogeneous catalysis. He showed how advanced sol-gel processing nanochemistry can be used to encapsulate, for example, ionic liquids and convert them from liquid to solid state.

Catalytic microreactors, he explained, have a potential to bridge between homogeneous and heterogeneous catalysis by the microencapsulation of catalyst dissolved or dispersed in non-volatile phase such as a ionic liquid.

Francesco Parrino, a post-doctoral researcher in the Schiavello-Grillone research group of Palermo’s University, presented the new results obtained in photocatalytic bromine synthesis. An eco-friendly and economic process capable to replace current industrial production via oxidation of bromide ions using gaseous chlorine is highly desirable, he explained opening his presentation.

Giuseppe Bagnato, a PhD student at Heriot-Watt University, United Kingdom, presented posters in the field of catalytic membrane reactor technology which he is now working to integrate in biorefinery.

His poster entitled “Hydrogenation of Bio-Oil: A Thermodynamic Study ” was awarded the best poster presentation prize – an online subscription to Catalysis Science & Technology, the RSC flagship catalysis journal with which the organisers of FineCat have partnered since the first edition of the Symposium in 2012.

Giuseppe was presented with a certificate signed by the journal’s Executive Editor, Dr Anna Simpson.

A full report of the conference proceedings can be found here.

The 7th edition of FineCat will be held in Sicily on 8th April 2018.

 

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15th National Youth Catalysis Conference – China

Catalysis Science & Technology is proud to announce that it awarded poster prizes at the 15th National Youth Catalysis Conference, “Multidisciplinary and multi-scale catalytic science and technology”, in China. The conference was held on 19th July 2015, at the University of Science and Technology of China (USTC), in Hefei. Plenary lectures were given by Professor Qingbai Xu (Tsinghua University), Professor Ye Wang (Xiamen University), Professor Wenjie Shen (Dalian Insitute of Chemical Physics, CAS), Professor Jiaguo Yu (Wuhan University of Technology) and Professor Baoning Zong (SINOPEC research institute of petroleum processing). Professors Wang, Shen and Yu are pictured below (left-right), together with the prize winners, Professor Weixin Huang (USTC, the local Chair) and Catalysis Science & Technology Associate Editor, Professor Ding Ma (Peking University).

The Winners:

Di Xin (Dalian University of Technolgy)

Ding Liangbing (University of Science and Technology of China)

Song Xiaojing   (Jilin University)

Han Lupeng (East China Normal University)

Su Xiaojuan (Ningxia University)

Chen Lang (Hunan University)

Su Diefeng (Zhejing University)

Wei Mingming (Dalian Institute of Chemical Physics, CAS)

Wang Dandan   (Xiamen University)

Gu Jing (Nanjing University)

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New Associate Editor for Catalysis Science & Technology

DingMa Professor Ding Ma has become Catalysis Science & Technology‘s newest Associate Editor.

Professor Ma is currently Professor at Peking University in China. He is handling papers already so submit your best work to him now.

His research focuses on heterogeneous catalysis, particularly when applied to energy innovation, for example methane and syngas conversion. He also works on developing new reaction routes for sustainable chemistry and in situ spectroscopic methods which can be used to study reaction mechanisms.

Professor Ma hopes that his expertise will contribute to the excellence of CS&T, and make this flagship catalysis journal of the Royal Society of Chemistry the best place for scientists in the catalytic community to publish their work and researchers to read exciting results.

On behalf of Professor Ma and the rest of our Editorial Board, we would like to invite you to submit your best work to Catalysis Science & Technology.

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Poison or not poison… Another side to sulfur

Sara Coles is a guest web-writer for Catalysis Science & Technology. She currently works for Johnson Matthey in Royston, UK.


Sulfur is normally thought of as a catalyst poison – but a Perspective article in Catalysis Science and Technology, by Alan McCue and  James Anderson at the University of Aberdeen, UK, reports on a growing quantity of work suggesting that it can act as an activity promoter or selectivity modifier in heterogeneous catalysis.

Catalytic metals including rhodium, platinum and palladium are well known for being susceptible to sulfur as a poison, however the effect is perhaps not as simple as first perceived – it has been suggested that the effects of sulfur have a degree of long range character, indicating that a small quantity of adsorbed sulfur may have a disproportionate effect on catalytic properties.

Many industrial feedstockSchematic representation of how relative activity varies with approximate wt% sulfur per unit mass catalysts and even biomass derived feedstocks contain sulfur to some extent which may influence catalytic performance. With more than 100 references, this article may provide a useful source of further information on this very relevant topic.

The authors present examples from Fischer–Tropsch synthesis, catalytic reforming, regio- and chemoselective hydrogenation as well as CO oxidation, hydrocarbon oxidation and NOx reduction.

Find out more by reading the article:
Sulfur as a catalyst promoter or selectivity modifier in heterogeneous catalysis

Catal. Sci. Technol., 2014, DOI: 10.1039/C3CY00754E

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All that glitters – gold and palladium serve catalysis needs

Sara Coles is a guest web-writer for Catalysis Science & Technology. She currently works for Johnson Matthey in Royston, UK.


Gold-palladium nanoparticles are hot stuff when it comes to catalysis. Catalysis Science and Technology’s themed issue, entitled ‘Gold Catalysis’, highlights just three examples of the many studies that regularly appear in the literature.

A minireview from Pasi Paalanen et al., Utrecht University, gives an overview of recent developments in the synthesis of supported gold-based bimetallic nanoparticles for catalytic applications. They focus on three major structural features to be characterised and, where possible, controlled: size, composition and nanostructure. They highlight selected literature examples in which gold-palladium nanoparticles were found to be active for reactions such as CO oxidation, vinyl acetate synthesis, cyclotrimerization of acetylene to benzene, selective oxidation of alcohols to aldehydes or ketones, direct synthesis of hydrogen peroxide, hydrocarbon hydrogenation, oxidation of primary C–H bonds, hydrodechlorination and hydrodesulfurization.

chloronitrobenzene hydrogenation and hydrogen peroxide synthesis over gold palladium nanoparticlesMeanwhile Elena Corbos and her colleagues at Johnson Matthey Technology Centre, in collaboration with Synchrotron Soleil, France, and University College London, present some original research on the preparation of bimetallic PdAu nanocatalysts. They tested the catalysts for the selective hydrogenation of 2-chloronitrobenzene to 2-chloroaniline and the direct formation of hydrogen peroxide. They found that a Pd-rich surface offered superior selectivity and reaction rates for 2-chloronitrobenzene hydrogenation, while for hydrogen peroxide synthesis, an optimal quantity of gold was required to ensure high productivity.

Tatsumi Ishihara et al., Kyushu University, Japan, carried out synthesis of hydrogen peroxide by direct oxidation of hydrogen in air on gold-palladium/titania. They report that the H2 conversion and H2O2 selectivity were strongly affected by the crystal phase of the titania. With increasing H2 pressure, H2O2 selectivity increased on AuPd/rutile TiO2 and the yield of became higher than on brookite or anatase TiO2 at 1.0 MPa. The effects of fluorinated hydrocarbon addition to reaction media were also studied.

Find out more about all this research in Catalysis Science and Technology.

Progress in controlling the size, composition and nanostructure of supported gold–palladium nanoparticles for catalytic applications
Pasi Paalanen, Bert M. Weckhuysen and Meenakshisundaram Sankar
Catal. Sci. Technol., 2013,3, 2869-2880, DOI: 10.1039/C3CY00341H

Tuning the properties of PdAu bimetallic nanocatalysts for selective hydrogenation reactions
Elena C. Corbos, Peter R. Ellis, James Cookson, Valérie Briois, Timothy I. Hyde, Gopinathan Sankar and Peter T. Bishop
Catal. Sci. Technol., 2013,3, 2934-2943, DOI: 10.1039/C3CY00255A

Effects of fluorinated hydrocarbon addition on H2O2 direct synthesis from H2 and air over an Au–Pd bimetallic catalyst supported on rutile-TiO2
Tatsumi Ishihara, Kohei Shigeta, Yuuki Ooishi, Maki Matsuka, Hidehisa Hagiwara and Shintaro Ida
Catal. Sci. Technol., 2013,3, 2971-2975, DOI: 10.1039/C3CY00273J

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Chemical Cross-linking of lipase in Mesoporous silica: A new addition to the enzyme immobilization kit

themed issue on Enzyme Immobilization was recently published in Chemical Society Reviews encompassing the advances made in the field of enzyme immobilization and its importance in the Industrial arena. The credit goes to a simple discovery by Nelson and Griffin, who in 1916 rediscovered that artificial carrier-bound invertase on Al(OH)3 and charcoal was still catalytically active. They put to rest the claims that substances like charcoal caused inhibition of the enzymes (due to adsorption) and established that adsorption had no role in the decreased activity of the enzymes. This discovery laid the foundation for the immobilized enzymes to find wide applications in the chemical industry.

The carriers used for immobilization include natural and synthetic polymers like cellulose, starch,  polystyrene, sephadex and inorganic carriers like clay, kaolinite, silica gel etc. Of these, Mesoporous silica materials (MPS) have been found to be an attractive alternative due to their intrinsic properties. The immobilization of the enzymes on these carriers are generally carried out by physical adsorption or covalent binding, but face the problem of enzyme leaching. In order to overcome this problem, the Cross-linked enzyme aggregates (CLEAs) method has emerged of late and has been successful to a certain extent. In the present paper, the authors have explored the CLEAs of lipase from Candida sp. 99-125 immobilized in MPS and found them to be thermally and catalytically stable with  improved enzymatic activities.

As a measure of their improved properties, the activity and stability of the Cross-linked lipases in MPS (nicknamed CLL@MPA) were compared with the simple adsorbed lipases (ADL@MPA) and the native enzymes, and were found to be highly stable (at high temperatures as well as on shaking) with improved hydrolytic, esterification and transesterification activites. Although these lipases (from candida sp. 99-125) were less active than the commercially available Novzyme 435 (from candida antarctica), their cheaper costs make them a promising alternative for industrial applications.

This study thus paves the way for cheaper and effective enzyme immobilization options, which can be further extended to other enzymes and lead to potential advances in various enzyme-based industrial processes.

Lipase Candida sp. 99-125 CLEAs in MPS

Lipase CLEAs in mesoporous silica- a robust biocatalyst with increased stability and recyclability

Read more at:

Formation of lipase Candida sp. 99-125 CLEAs in mesoporous silica: characterization and catalytic properties
Jing Gao
,   Lianlian Shi,   Yanjun Jiang,   Liya Zhou and   Ying He
Catal. Sci. Technol.
, 2013, Accepted Manuscript
DOI:
10.1039/C3CY00412K


Shreesha Bhat, Web Writer Shreesha Bhat is a M.S.(Pharm.) in Medicinal Chemistry from National Institute  of  Pharmaceutical  Education and Research,  India. His area of interests  include  chemical  synthesis of biologically important  molecules  and developing  newer    methods for organic  synthesis using novel catalysts.

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Art in action: Novel Sulfated Zirconia as bifunctional catalysts

With context to the ever increasing problem of dwindling energy resources, sugars like 5-Hydroxymethylfurfural (5-HMF) and furfural are considered to be the key for next-generation energy demands. These sugars have been recently identified to have potential applications in the petrochemicals and plastic industry. While efforts are ongoing to find a cheaper and greener way for the production of 5-HMF, it has eluded most of the researchers till now.

In their quest for a total green 5-HMF synthesis, the authors moved towards sulfated zirconia as a bifunctional catalyst for the one-pot conversion of glucose to 5-HMF in aqueous phase. It has been observed that isomerisation of glucose to fructose is possible with zirconia, and the subsequent dehydration of fructose to 5-HMF with sulfated zirconia (SZ). The authors tried to capitalize on their previous experience of employing SZ in aqueous media and went on to create the first ever bifunctional catalyst for 5-HMF production in water. The key towards the holy grail was tuning the acid strength in SO2/ZrO2 to achieve both the isomerisation and dehydration through a single bi-functional catalyst.

Sulfated Zirconia as bifunctional catalysts

The amphoteric nature of  zirconia was explored and tuned by adjusting the sulfate loading onto the metal, as the surface sulfate density directly relates to the acidity of the catalyst. The extensive investigations by the researchers showed that zirconia exists in a monoclinic state with large lewis base sites, which converts to a more stable tetragonal structure on sulfate addition with abundance of bronsted acid sites. The lewis base sites catalysed the glucose –> fructose isomerisation and the bronsted acid sites accelerated the fructose –> 5-HMF dehydration. This knowledge helped them in optimising the sulfate loading to 0.3 ml which gives a perfect platform for Glucose –> Fructose –> 5-HMF conversion.

To read more about the art of synthesizing such novel bifunctional catalysts, follow the link below:

Bifunctional SO4/ZrO2 catalysts for 5-hydroxymethylfurfural (5-HMF) production from glucose

Catal. Sci. Technol., 2013, Accepted Manuscript
Shreesha Bhat, Web Writer Shreesha Bhat is a M.S.(Pharm.) in Medicinal Chemistry from National Institute  of Pharmaceutical        Education and Research, India. His area of interests  include chemical synthesis of biologically important  molecules and developing  newer methods for organic synthesis using novel catalysts.
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Pd Nanocubes: A new customizable weapon for enantioselective hydrogenation

Ever heard of a customizable catalyst? A catalyst with a unique shape? A catalyst which with a change in size can provide different activity? If not, then here is a catalyst- an easy to prepare Pd nanocube which you can customize as per the activity desired: racemic or enantioselective hydrogenation of α,β-unsaturated carboxylic acids.

The enantioselective hydrogenation of aliphatic α,β-unsaturated carboxylic acids faces the obstacle of lower enantioselectivities as the aliphatic substituent is not armed to curb the inevitable isomerization of the double bonds in the structure. High enantioselectivities have been observed in cases of aryl substituted α,β-unsaturated carboxylic acids owing to the stabilizing effect of the aryl substituent at the β-position. With no effective solutions up-to-date, the researchers at Chinese Academy of Sciences tried to find the answer to this problem in the world of micromeretics and morphology.

Considering the previous instances where the sizes and shape of the catalysts did play a role in the enantioselectivity, the researchers tried to capitalize on this and were indeed rewarded with fruitful results. They decided to study the effects of shape and size, by preparing both cubic and spherical Pd nanoparticles as catalysts for the enantioselective hydrogenation of unsaturated carboxylic acids. The studies conducted by the Shen group clearly indicate that the Pd nanocubes have a upperhand, as they provide good enantioselectivities as compared to the spherical nanoparticles. They also found that the Pd nanocubes of larger size provided with excellent enantioselecctivities as compared to the smaller nanocubes. The dynamics of this can be explained by the fact that larger nanocubes, which have more flat sites, can easily accommodate the chiral modifier (like cinchonidine) on its surface along with the substrate, thus resulting in higher enantioselectivities. Meanwhile, the smaller nanocubes provided higher yields, as they are equipped with more edge sites, which accelerates the process of hydrogenation. The present study provides with a customizable formula with both small and large nanocubes put to different use.

Activity desired Pd Nanocubes customized to
Racemic Hydrogenation at High yields Small  size
Enantioselective Hydrogenation at Lower yields Large size

Thus, the present paper brings forward the fresh concept of customized Pd nanocubes, which can be an effective weapon in the armory of catalysts for enantioselective hydrogenation of α,β-unsaturated carboxylic acids.

Palladium nanocubes as customizable weapons for enantioselective hydrogenation

Customizable Palladium Nanocubes for Racemic/Enantioselective hydrogenation

To read more, follow the link below:

Enantioselective hydrogenation of α,β-unsaturated carboxylic acids on Pd nanocubes
Chunhui Chen, Ensheng Zhan, Na Ta, Yong Li and  Wenjie Shen

Catal. Sci. Technol., 2013, Advance Article
DOI:
10.1039/C3CY00314K

Shreesha Bhat, Web Writer Shreesha Bhat is a M.S.(Pharm.) in Medicinal Chemistry from National Institute of Pharmaceutical        Education and Research, India. His area of interests include chemical synthesis of biologically important  molecules and developing newer methods for organic synthesis using novel catalysts.

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Turn up the heat – Thermal treatment key to magnetically recoverable AuPd nanoparticles

Aldehydes are valuable synthetic intermediates with many methods for their preparation. But the majority of these approaches employ stoichiometric oxidants that produce toxic waste. Aerobic oxidation with molecular oxygen and a transition metal catalyst offers an environmentally benign alternative. In this advance article, Rossi and colleagues reported the first magnetically recoverable AuPd nanoparticle catalyst applied to the oxidation of primary alcohols to aldehydes.

The removal of metal catalysts supported on magnetic surfaces with an external magnetic field is an innovative and efficient method for separation.  The researchers achieved linkage by dually functionalizing the support with strongly coordinating ligands and impregnating the nanoparticles with weak coordinating groups in the coordination capture method. They found that catalysts with amino-functionalized silica supports exhibited higher activity and stability to catalyst recycling than the analogous thiol supports. The authors achieved a 92% conversion of benzyl alcohol with high selectivity for benzaldehyde using 1 wt% AuPd catalyst (Fe3O4@SiO2-NH2-AuPd) under 6 bar of O2 at 100 °C. However, catalyst separation was impeded by the amino group, which had reacted with the product benzaldehyde to form an aldimine.

This issue was circumvented through the calcination of the Fe3O4@SiO2-NH2-AuPd catalyst at 500 °C for 2 hours, effectively removing the amino groups and promoting highly efficient catalyst recovery. Good yield and selectivity for the oxidation reaction was maintained and the catalyst was used in five successive reactions without loss of selectivity.

To read more, follow the link below:

Magnetically recoverable AuPd nanoparticles prepared by a coordination capture method as a reusable catalyst for green oxidation of benzyl alcohol

Tiago A. G. Silva, Richard Landers and Liane M. Rossi

Catal. Sci. Technol., 2013, Advance Article, DOI: 10.1039/c3cy00261f

Tien Nguyen is a web contributor working towards her PhD in David Nicewicz’s research  group at the University of North Carolina at Chapel Hill, USA. Her current area of research  focuses on anti-Markovnikov hydroamination of alkenes using photoredox catalysis

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