نتایج جستجو برای: alkali catalyst

تعداد نتایج: 60055  

2010
A. A. Refaat

Biodiesel production is worthy of continued study and optimization of production procedures due to its environmentally beneficial attributes and its renewable nature. Heterogeneous transesterification is considered to be a green process. The process requires neither catalyst recovery nor aqueous treatment steps and very high yields of methyl esters can be obtained, close to the theoretical valu...

Journal: :Bioresource technology 2011
Saeid Baroutian Mohamed K Aroua Abdul Aziz A Raman Nik M N Sulaiman

In this study, a novel continuous reactor has been developed to produce high quality methyl esters (biodiesel) from palm oil. A microporous TiO2/Al2O3 membrane was packed with potassium hydroxide catalyst supported on palm shell activated carbon. The central composite design (CCD) of response surface methodology (RSM) was employed to investigate the effects of reaction temperature, catalyst amo...

Journal: :Bioresource technology 2012
Muhammad Ayoub M S Khayoon Ahmad Zuhairi Abdullah

The synthesis of oxygenated fuel additives via solvent freebase-catalyzed etherification of glycerol is reported. The products of glycerol etherification arediglycerol (DG) and triglycerol (TG) with DG being the favorable one. The catalytic activity of different homogeneous alkali catalysts (LiOH, NaOH, KOH and Na(2)CO(3)) was investigated during the glycerol etherification process. LiOH exhibi...

2017
Ke-Chang Hung Chen-Ning Yang Teng-Chun Yang Tung-Lin Wu Yong-Long Chen Jyh-Horng Wu

This study was compared and characterized two different alkali (potassium carbonate (PC) and potassium acetate (PA))-catalyzed acetylations of slicewood with vinyl acetate (VA) by a vapor phase reaction. The results revealed that the esterification reaction between VA and the hydroxyl groups of slicewood could be improved by using PC or PA as a catalyst. Additionally, a significant weight perce...

2007

INTRODUCTION Enantioselective Catalysis Beginning with the first homogeneous asymmetric metal-catalyzed reaction performed by Noyori—a cyclopropanation—the area of enantioselective catalysis in organic chemistry has become a major topic of discussion and research. Homogeneous, asymmetry-inducing catalysts have been developed for a wide range of reactions, especially notable are those developed ...

2001
Randell L. Mills Takeyoshi Onuma Ying Lu

We report the generation of a plasma of hydrogen and certain alkali ions as recorded via EUV spectroscopy and the hydrogen Balmer and alkali line emissions in the visible range. Typically a hydrogen plasma is generated and the emission of extreme ultraviolet light from hydrogen gas is achieved via a discharge at high voltage, a high power inductively coupled plasma, or a plasma created and heat...

Ahmad Shaabani, Ayoob Bazgir Masoumeh Sharifi Kiasaraie Sakineh Arab Ameri Sima Samadi

Alkali and alkaline earth metals hydrogen sulfate catalyzed the one-pot three component condensation reactions of aldehydes, 1,3-dicarbonyl compounds and urea or thiourea under solvent-free conditions leading to 3,4-dihydropyrimidin-2(1H)-ones in high yields at 80 °C. Our results showed that Biginelli reaction not only is pH dependent, but the cation of catalyst plays an importan...

2013
Masahisa Kakiuchi

The D/H ratios of hydrogen gas in equilibrium with aqueous alkali halide solutions were determined at 25 °C, using a hydrophobic platinum catalyst. The hydrogen isotope effect between the solution and pure water changes linearly with the molality of the solution at low concentrations, but deviates from this linearity at higher concentration for all alkali halide solutions. The magnitude of the ...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2007
ahmad tavasoli kambiz sadaghiani abbas ali khodadadi yadollah mortazavi

in a novel dual bed reactor fischer-tropsch synthesis was studied by using two diffrent cobalt catalysts. an alkali-promoted cobalt catalyst was used in the first bed of a fixed-bed reactor followed by a rutenuim promoted cobalt catalyst in the second bed. the activity, product selectivity and accelerated deactivation of the system were assessed and compared with a conventional single bed react...

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