DR ANTHONY MELVIN CRASTO,WorldDrugTracker, helping millions, A 90 % paralysed man in action for you, I am suffering from transverse mylitis and bound to a wheel chair, With death on the horizon, nothing will not stop me except God
DR ANTHONY MELVIN CRASTO Ph.D ( ICT, Mumbai) , INDIA 30 Yrs Exp. in the feld of Organic Chemistry. Serving chemists around the world. Helping them with websites on Chemistry.Millions of hits on google, world acclamation from industry, academia, drug authorities for websites, blogs and educational contribution
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Showing posts with label PROCESS. Show all posts
Showing posts with label PROCESS. Show all posts

Wednesday 21 August 2013

Direct synthesis of hydrogen peroxide in water in a continuous trickle bed reactor optimized to maximize productivity



Hydrogen peroxide direct synthesis was studied in continuous mode over a 5% wt Pd/C commercial catalyst in a Trickle Bed Reactor. The target of the study was to maximize the hydrogen peroxide production. The catalyst was uniformly diluted in quartz sand at different concentrations to investigate their effects on the direct synthesis.
The amount of catalyst and the distribution of the catalyst along the bed were optimized to obtain the highest possible yield. The distribution of the catalyst along the bed gave the possibility to significantly improve the selectivity and production of hydrogen peroxide (up to 0.5% under selected conditions). Higher production rate and selectivity were found when the catalyst concentration was decreased along the bed from the top to the bottom as compared to the uniformly dispersed catalyst.
The H2/Pd ratio was found to be an important parameter that has to be investigated in the hydrogen peroxide direct synthesis. The effect of a pretreatment of the catalyst with a solution of sodium bromide and phosphoric acid was studied; the results showed how a catalyst pretreatment can lead to a real green hydrogen peroxide synthesis in water. Some optimization guidelines are also provided.
Green Chem., 2013, 15,2502-2513
DOI: 10.1039/C3GC40811F, Paper


*
Corresponding authors
a
Department of Chemical Engineering, Åbo Akademi University, Turku/Åbo, Finland
E-mail: bpierdom@abo.fi ;
Fax: +358 2 215 4479 ;
Tel: +358 2 215 4555
b
Department of Chemical Engineering and Environmental Technology, University of Valladolid, Valladolid, Spain
E-mail: jgserna@iq.uva.es
Hydrogen peroxide direct synthesis was studied in continuous mode over a 5% wt Pd/C commercial catalyst in a Trickle Bed Reactor.

Iodine-mediated arylation of benzoxazoles with aldehydes



A simple and efficient methodology for the arylation of benzoxazoles with aldehydes using iodine as the mediator has been developed. The reaction proceeded smoothly with a range of substrates to give the corresponding arylated products in moderate to good yields
Green Chem., 2013, 15,2365-2368
DOI: 10.1039/C3GC41027G, Communication


*
Corresponding authors
a
Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, Singapore 138669, Singapore
E-mail: ygzhang@ibn.a-star.edu.sg ;
Fax: (+65) 6478-9020
A simple and efficient methodology for the arylation of benzoxazoles with aldehydes using iodine as the mediator has been developed

Friday 26 July 2013

One-Pot Approach to α,β-Unsaturated Carboxylic Acids

thumbnail image: One-Pot Approach to α,β-Unsaturated Carboxylic Acids

 

One-Pot Approach to α,β-Unsaturated Carboxylic Acids

Carboxylation of alkynes with carbon dioxide in a one-pot approach could become a practical route to unsaturated carboxylic acids
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Concise Total Synthesis of a Newly Discovered Alkaloid

 








A concise synthesis of a novel alkaloid natural product with the pyrroloindoloquinazoline skeleton has been devised
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Tuesday 23 July 2013

Nano-Technoloogy Makes Medicine Greener


The ultra small nanoreactors have walls made of lipids. During their fusion events volumes of one billionth of a billionth of a liter were transferred between nanoreactors allowing their cargos to mix and react chemically. We typically carried out a million of individual chemical reactions per cm2 in not more than a few minutes. (Credit: Image courtesy of University of Copenhagen)http://www.sciencedaily.com/releases/2011/11/111103132357.htm
 Researchers at the University of Copenhagen are behind the development of a new method that will make it possible to develop drugs faster and greener. Their work promises cheaper medicine for consumers.
Over the last 5 years the Bionano Group at the Nano-Science Center and the Department of Neuroscience and Pharmacology at the University of Copenhagen has been working hard to characterise and test how molecules react, combine together and form larger molecules, which can be used in the development of new medicine.http://www.sciencedaily.com/releases/2011/11/111103132357.htm



Tuesday 16 July 2013

A new labdane diterpene from Rauvolfia tetraphylla Linn. (Apocynaceae)

A new labdane diterpene from Rauvolfia tetraphylla Linn. (Apocynaceae)
A new labdane diterpene from Rauvolfia tetraphylla Linn. (Apocynaceae)

Rauvolfia tetraphylla Linn. (syn. R. canescens L., family: Apocynaceae) holds an important position in the Indian traditional system of medicine, and has other immense applications. This particular plant is regarded as a rich source of a wide variety of important alkaloid constituents such as reserpine, reserpiline, raujemidine, isoreserpiline, deserpidine, aricine, ajmaline, ajmalicine, yohimbines, serpentine, sarpagine, vellosimine and tetrphylline. However, there is no report on the terpenoid constituent from this plant, and we report the isolation from the air-dried stems and branches of R. tetraphylla and structural elucidation of a new labdane diterpene, 3-hydroxy-labda-8(17),13(14)-dien-12(15)-olide (1; Fig. 1) bearing  an unusual -lactone moiety.
Structure of labdane diterpene
Fig. 1 Structure of labdane diterpene
Goutam Brahmachari*, Lalan Ch. Mandal, Dilip Gorai, Avijit Mondal, Sajal Sarkar and Sasadhar Majhi
Doi: 10.3184/174751911X13220462651507

read all at

Novel uses of nanoparticle catalytic systems

Novel uses of nanoparticle catalytic systems
Novel uses of nanoparticle catalytic systems

Easily prepared and recoverable nanoparticles with a diameter of 10–40 nm, with a high surface area and stability may provide a catalytic system or the support for a catalyst.

Thursday 4 July 2013

Catalyst duo exerts powerful stereocontrol

diastereomer
The dual catalyst enables selective access to the required stereoisomer © Science/AAAS

Chemists from the Swiss Federal Institute of Technology, ETH Zurich, have teamed chiral catalysts in pairs to selectively drive a reaction towards desired stereoisomeric products with high selectivity. Each catalyst activates one reagent and controls its substituent arrangement as it bonds to the other to form two neighbouring chiral centres. ‘We have shown that it is possible to develop fully stereodivergent reaction processes,’ says Erick Carreira, who led the work. ‘We expect that additional reactions displaying full stereodivergency will be identified.’

read all at
http://www.rsc.org/chemistryworld/2013/05/catalyst-duo-powerful-stereocontrol-diastereomer

References

S Krautwald et alScience, 2013, DOI: 10.1126/science.1237068

Thursday 27 June 2013

A molecular database for developing organic solar cells


molecular_space_logo




Harvard researchers have released a massive database of more than 2 million molecules that might be useful in the construction of solar cells that rely on organic compounds for construction of organic solar cells for the production of renewable energy. Developed as part of the Materials Genome Initiative launched by the White House’s Office of … more…

http://www.kurzweilai.net/a-molecular-database-for-developing-organic-solar-cells?utm_source=KurzweilAI+Daily+Newsletter&utm_campaign=4fc1bf53a4-UA-946742-1&utm_medium=email&utm_term=0_6de721fb33-4fc1bf53a4-282116853





Monday 10 June 2013

ORGANIC CHEMISTRY REACTIONS, website by DR ANTHONY CRASTO

 

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https://sites.google.com/site/anthonycrastoreactions/home

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