This paper presents the evolution of alkyne metathesis since the early discoveries, essentially from the catalyst point of view. It is shown that although well defined carbynes may be useful for this reaction, further work has been made, aimed at the synthesis of new catalysts or catalytic systems, based on molybdenum precursors , associated or not with phenolic cocatalysts. The major objective...

in this paper, modeling and optimization of fischer-tropsch synthesis is considered in a fixed-bed catalytic reactor using an industrial fe-cu-k catalyst. a one dimensional pseudo-homogenous plug flow model without axial dispersion is developed for converting syngas to heavy hydrocarbons. the effects of temperature, pressure, h2 to co ratio in feed stream, and co molar flow on the mass flow rat...

An environmentally benign and clean synthesis of aryl-hydrazones by reacting variety of carbonyl compounds with thiosemicarbazide, semicarbazide, aminoguanidine, and phenyl hydrazine has been achieved using aqueous extract of Acacia concinna pods as a natural surfactant type catalyst. We found that the aqueous extract of Acacia concinna pods could be effectively used for the synthesis of aryl-h...

Polypyrrole is one of the most useful conductive polymers, but green synthesis of this polymer has been restricted until now. The objective of the present paper is green synthesis of nano polypyrrole (PPy) by oxidative polymerization using urea-hydrogen peroxide. It was found that conductivity and morphology of polypyrrole are highly dependent on the reaction conditions such as the molar ratio ...

a convenient, rapid, and one-pot method for the synthesis of azo dyes has been developed. in this protocol, diazotization reagent (arn2+ -cro3–sio2) was prepared via grinding of aromatic amines, nano2, wet sio2 and nano silica chromic acid (nano-sca) without solvent at room temperature. the obtained diazotization reagent was sufficiently stable to be kept at room temperature in the dry state fo...

cuals2  chalcopyrite  nanocrystalline  are  synthesized  with  facile method.  the  heat  arrested  solvothermal  method  for  synthesize nanocrystalline  were  investigated.  the  time  duration  of  synthesis, temperature of solution and metal salts to solvent molar ratio can be parameters  that we are  studied. the nanoparticles were  synthesized with cucl, alcl3 and  thiourea (sc(nh2)2) as ...

in this scientific research work we report a novel method to synthesis co3o4 nanoparticles via calcinations of cobalt hydroxide which can be conveniently prepared by the co(no3 )2.6h2o with different reactants. in order to study the effect of calcination temperature on structure and morphology of the nanoparticles, the calcinations take place at various temperatures (at 300°c, 500°c and 700°c)....

The energetic cost of protein synthesis is thought to account for a significant proportion of total metabolism. However, attempts to estimate the energetic cost of synthesizing proteins have resulted in surprisingly variable results, particularly for the small number of polar organisms studied, where cost estimates vary by two orders of magnitude. Much of this variability is probably the result...