نتایج جستجو برای: selective synthesis

تعداد نتایج: 597246  

Zeolite ZSM-5 presents a great source of interest in catalysis because of its shape selective properties. The absence of a relationship between the template size and shape of the structure generated during the synthesis of zeolites is illustrated by the case of ZSM-5. In this study, we have investigated the role of ethanol, methyltriphenylphosphonium bromide (MTPBr) and cetyltrimethylammonium b...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - دانشکده علوم 1390

in this thesis, a better reaction conditions for the synthesis of spirobarbiturates catalyzed by task-specific ionic liquid (2-hydroxy-n-(2-hydroxyethyl)-n,n-dimethylethanaminium formate), calcium hypochlorite ca(ocl)2 or n-bromosuccinimide (nbs) in the presence of water at room temperature by ultrasonic technique is provided. the design and synthesis of spirocycles is a challenging task becaus...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید بهشتی 1356

چکیده ندارد.

An efficient synthesis of the 1,l'-dihydroxy-2,2'-(thiodimethy1ene)bis-9(10H)- anthrone (5) is described. Reaction of 1 -methoxy-2-(bromomethy1)-9,lOanthraquinone (1) with excess sodium sulfide in ethanol, demethylation to the corresponding hydroxy and subsequent selective reduction produced the title compound in high yield.

We have introduced a selective synthesis of tertiary amines using alkyl halide and ammonium salts as the amine sources in water. This green process has outstanding superiorities, such as being eco-friendly, possessing ammonium salts, and using water as a green solvent in the absence of organic ligands or catalysts. It is worth mentioning that the presence of t-Butyl alcohol and potassi...

Journal: :international journal of nanoscience and nanotechnology 2014
s. abbasian m. taghizadeh

h-zsm-5 nano-zeolites were synthesized by hydrothermal method using tetrapropylammonium hydroxide (tpaoh) as a template in the presence of various tpabr concentrations. the effect of different tpabr/tpaoh molar ratios was studied on the catalytic performance of dehydration of methanol to dimethyl ether (dme) in a fixed bed reactor under the same operating conditions (t=300°c, p=1 atm, and whsv=...

Journal: :Chinese Journal of Organic Chemistry 2015

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