نتایج جستجو برای: reaction yield
تعداد نتایج: 593730 فیلتر نتایج به سال:
abstract in aggregate, active forms of reactive silica with mineral names are sometimes associated with sand and gravel in concrete mixture. alkali hydroxides originated from alkalis in the cement or other resources form an alkaline silica gel with this reactive silica which becomes swallowed and expanded during time causing damage to concrete. there have been growing researches on alkaline r...
The ultrasound-assisted (UA) soybean oil methanolysis using KOH as a catalyst was studied at different reaction conditions in a microreactor. Box–Behnken experimental design, with three variables, was performed and the effects of three reaction variables i.e. reaction temperature, catalyst concentration and the methanol-to-oil molar ratio on fatty acid methyl ester (FAME) yield were evaluated b...
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...
In the present work, we have synthesizedgadolinium(III) bromide, GdBr3 from the gadolinium oxide, Gd2O3 by sintering brominating with ammonium bromide, NH4Br. The influence of three main synthesis parameters (contact time, stoichiometry, and temperature) on the reaction yield was studied and optimized. This study showed that the optimum conditions...
The cycloalkylation of diethyl malonate and ethyl cyanoacetate with alkyl dihalide was investigated by using comminuted potassium carbonate as a base and toluene as a solvent in the presence of hexadecyltrimethylammonium bromide (HTMAB) as a phase-transfer catalyst, which provided a conventional procedure with the advantage of short reaction period and high product yield. The factors influencin...
the cycloalkylation of diethyl malonate and ethyl cyanoacetate with alkyl dihalide was investigated by using comminuted potassium carbonate as a base and toluene as a solvent in the presence of hexadecyltrimethylammonium bromide (htmab) as a phase-transfer catalyst, which provided a conventional procedure with the advantage of short reaction period and high product yield. the factors influencin...
ZrP2O7 nanoparticles have been used as an efficient catalyst for the preparation of 2-aryl-5-methyl-2,3-dihydro-1H-3-pyrazolones by a simple one-pot four-component reaction of phenyl hydrazines, ethyl acetoacetate ,β-naphthol and benzaldehydes under microwave irradiation in good to excellent yields. When the reaction was carried out using ZrOCl2.8H2O, ZrO2 and ZrP2O7 NPs as the catalyst, the pr...
A one-step synthesis of monoterpene alcohols such as lavandulol, linalool and geraniol/nerol from hemiterpene alcohols proceeds efficiently in supercritical water (scH2O) without any catalyst. Our device of a microreaction (μ-reaction) system achieves the production of lavandulol in 82% selectivity and 59% yield, respectively, even at a short reaction time of 7.7 s at 30 MPa and 375 in the near...
ZrP2O7 nanoparticles have been used as an efficient catalyst for the preparation of 2-aryl-5-methyl-2,3-dihydro-1H-3-pyrazolones by a simple one-pot four-component reaction of phenyl hydrazines, ethyl acetoacetate ,β-naphthol and benzaldehydes under microwave irradiation in good to excellent yields. When the reaction was carried out using ZrOCl2.8H2O, ZrO2 and ZrP2O7 NPs as the catalyst, the pr...
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