A new model based on a combination of the polymeric multigrain and multilayer models has been developed to predict the polymerization rate, particle growth, morphology, effective parameters on broadening of the molecular weight distribution, number and weight average of the molecular weight, isotacticity index and bulk density of polymer. Mathematical correlations and the kinetics used in t...

the nano-cry zeolite synthesized and characterized by fourier transfer infrared (ft-ir), x-ray diffraction (xrd),and scanning electron microscopy (sem).the result show that nano catalyst prepared with mainly particles size about 30-80 nm .the xrd show the structure of the zeolite does not collapse. this nano-cry zeolite has been used as new, and nontoxic catalyst for catalyzes of synthesis of 2...

An ethoxy-bridged dinuclear indium catalyst was used for the ring opening polymerization of the cyclic ester β-butyrolactone to form the biodegradable polyester poly(hydroxybutyrate) (PHB). The catalyst shows remarkable activity and control during polymerization, allowing for formation of diblock polymers. Addition of high ratios of alcohols to the catalyst leads to fast chain transfer and immo...

Manganese oxide-loaded and -doped ceria as well as the corresponding barium-modified oxide catalysts were prepared for soot oxidation in the presence of NO(x), and were characterized by using X-ray diffraction, Brunauer-Emmett-Teller and NO temperature-programmed oxidation measurements. The activity of catalyst depended strongly on the NO2 production capacity, and the importance of surface nitr...

Singly occupied molecular orbital (SOMO) activation provides a pathway for asymmetric a-addition to aldehydes. The scope of SOMO activation includes the allylation, enolation, vinylation, styrenation, chlorination, polyene cyclization, and arylation of a range of aldehydes. This union of organocatalysis with single-electron oxidative coupling is an intricate process involving the complex balanc...

The mechanism of guanidine-catalyzed enantioselective isomerization of 3-alkynoates to allenoates is investigated using density functional theory methods. The calculations predict that the isomerization reaction includes two hydrogen-transfer steps and one conformational change mediated by the TBO catalyst. The first hydrogen-transfer step corresponds to the migration of hydrogen from C(4) of t...

Coordination polymers and metal-organic frameworks are appealing as synthetic hosts for mediating chemical reactions. Here we report the preparation of a mesoscopic metal-organic structure based on single-layer assembly of aluminium chains and organic alkylaryl spacers. The material markedly accelerates condensation reactions in water in the absence of acid or base catalyst, as well as organoca...

in this paper, we studied effect of different parameters including density, viscosity, interfacial tension and solute transfer concentration on phase inversion hold-up. the results showed that change in phase density ratio had no effect on phase inversion hold-up. it also disclosed that the phase viscosity ratio was the most effective parameter affecting phase inversion hold-up and each phase h...

Poly(ethylene terephthalate) (PET) powder was hydrolyzed at atmospheric pressure in 5-10 wt% aqueous NaOH at 95°C for 100 min using some phase transfer catalysts (PTC) with an intention to recover the starting monomers from the waste PET. The intent behind attempting new PTC was to carry out the reaction at milder conditions than those reported in the literature. One of the monomers, terephthal...