57 research outputs found
Hydrogen production via dehydrogenation of alcohols using ruthenium hexamethylenetetramine complex
No full textBeing a zero-carbon source, the hydrogen economy is considered to be better than the fuel economy as it produces only water vapor even after complete combustion. Still, it suffers from two major drawbacks, namely (1) the production of green hydrogen from sustainable resources and (2) the storage and transportation of hydrogen. The use of liquid organic hydrogen carriers (LOHCs) such as alcohols, amines, etc. has been found to be a better and more secure way to store and transport hydrogen. Catalytic hydrogenation and dehydrogenation of LOHCs using transition metal complexes are known as the best methods to load and unload hydrogen for storage and transportation. Here, in this article, we show the amount of hydrogen produced during the catalytic dehydrogenation of LOHCs like alcohols using a very simple and cheap gas burette method. The dehydrogenative oxidation of alcohols was done using a well-defined [Ru(p-cym)HMTA]Cl2 complex with a catalyst loading of 0.5 mol%. Hydrogen estimation was done for different alcohol substrates. A comparison was made between theoretical and experimental yields of the released hydrogen
Synthesis of a Water-Soluble Ruthenium Complex and Its Catalytic Activity for Acceptorless Alcohol Dehydrogenation in Aqueous Medium
No full textThe synthesis of a ruthenium complex bearing a PN-chelating ligand is described. The complex, in the presence of KOH, enabled the synthesis of ketones from secondary alcohols in the absence of a hydrogen acceptor in aqueous medium. This synthetic protocol, which uses water as the medium, is green and has a high atom economy as it avoids the use of an acceptor and produces hydrogen as the sole byproduct. Mechanistic investigations revealed that the catalytic cycle involves a phosphine dissociative pathway.</jats:p
Well-Defined Ruthenium Complex for Acceptorless Alcohol Dehydrogenation in Aqueous Medium
No full textAcceptorless and base-free dehydrogenation of alcohols and amines using ruthenium-hydride complexes
No full textAn efficient, operatively simple, acceptorless, and base-free dehydrogenation of secondary alcohols and nitrogen-containing heterocyclic compounds was achieved by using readily available ruthenium hydride complexes as precatalysts. The complex RuH2(CO)(PPh3)3 (1) and Shvo’s complex (2) showed excellent activities for the dehydrogenation of secondary alcohols and nitrogen containing heterocycles. In addition to complexes 1 and 2, the complex RuH2(PPh3)4 (3) also showed moderate to excellent activity for the acceptorless dehydrogenation of nitrogen-containing heterocyclic compounds. Kinetic studies on the oxidation reaction of 1-phenylethanol using complex 1 were carried out in the presence and the absence of external triphenylphosphine (PPh3). External addition of PPh3 had a negative influence on the rate of the reaction, which suggested that dissociation of PPh3 occurred during the course of the reaction. Hydrogen was evolved from the oxidation reaction of 1-phenylethanol by using 1 mol% of 1 (88%) and 2 (92%), which demonstrated the possible usage of the catalytic systems in hydrogen generation
ChemInform Abstract: Acceptorless and Base‐Free Dehydrogenation of Alcohols and Amines Using Ruthenium‐Hydride Complexes.
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ChemInform Abstract: Tandem Synthesis of Amides and Secondary Amines from Esters with Primary Amines under Solvent‐Free Conditions.
No full textEntomopathogenic Fungi for the Management of Calopepla leayana on Gmelina arborea
No full textEntomopathogenic fungi, Beauveria bassiana and Metarhizium anisopliae were isolated and identified as natural pathogens of Calopepla leayana. Both the species of fungi were effective against the larval and adult stages of C. leayana causing white and green muscardine diseases respectively. It was also found that B. bassiana was more pathogenic to the pest as compared to M. anisopliae. The susceptibility of larvae and adults was negatively associated with the age and positively associated with the fungal spore concentration. In all the stages from I instar to adult, the highest mortality was observed in 10% of 1x109 spores/ml concentration of B. bassiana among 1, 2.5, 5 & 10% of 1x109 spores/ml concentration. It was also reflected in probit analysis that the concentration of spores required to kill fifty percent of the population was ranges from 0.09% to 5.98% of 1x109 spores/ml concentration of B. bassiana and 1.02% to 9.72% of 1x109 spores/ml concentration of M. anisopliae. The larvae of I instar have shown highest mortality, which gradually decreased with the increase in age or decrease in the concentration of fungal spores. Mass production of B. bassiana using different substrates was attempted to harvest ample amount of spores. This study revealed that spore production was directly proportional to the mycelial weight and incubation period. From the seven substrates tested, wheat flour was identified as one of the suitable substrates for the mass production of B. bassiana. A field trial was conducted to test their efficacy under field conditions. 72-93% mortality was observed in field conditions.-----------------------------------------------------------------------------------------------------Division of Bioprospecting, Institute of Forest Genetics and Tree Breeding, Coimbatore-641002, Tamilnadu, India*Corresponding author, Email: [email protected] This Article As: N. Senthilkumar and S. Murugesan. 2010. Entomopathogenic Fungi for the Management of Calopepla leayana on Gmelina arborea. J. Ecobiotechnol. 2(3): 01-0
Tandem Synthesis of Amides and Secondary Amines from Esters with Primary Amines under Solvent‐Free Conditions
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