نتایج جستجو برای: (trans)esterification

تعداد نتایج: 2388  

Journal: :Ultrasonics sonochemistry 2015
Preeti B Subhedar Claudia Botelho Artur Ribeiro Rita Castro Maria Alcina Pereira Parag R Gogate Artur Cavaco-Paulo

The synthesis of biodiesel from sunflower oil and methanol based on transesterification using the immobilized lipase from Thermomyces lanuginosus (Lipozyme TL-IM) has been investigated under silent conditions and under an ultrasound field. Ultrasound assisted process led to reduced processing time and requirement of lower enzyme dosage. We found for the first time that oil to methanol ratio of ...

2014
Ga Vin Kim WoonYong Choi DoHyung Kang ShinYoung Lee HyeonYong Lee

The aim of this study was to increase the yield of biodiesel produced by Scenedesmus sp. through in situ transesterification by optimizing various process parameters. Based on the orthogonal matrix analysis for the acidic catalyst, the effects of the factors decreased in the order of reaction temperature (47.5%) > solvent quantity (26.7%) > reaction time (17.5%) > catalyst amount (8.3%). Based ...

Journal: :journal of chemical and petroleum engineering 2015
kambiz tahvildari tahereh hajy heidar

due to the high price of virgin vegetable oils and the drawbacks of the homogeneous catalytic transesterification, in this work an economically profitable alternative process was proposed for biodiesel synthesis in which transesterification of the low-cost waste cooking oil (wco) with methanol in a heterogeneous system was done. alumina impregnated with sodium hydroxide was utilized as a solid ...

Journal: :journal of physical & theoretical chemistry 2011
a.r. abbaspour p. moaveni

transesterification, one of the most effective methods for ester synthesis, is usually conducted under acid or basicconditions. although quite a few methods have been reported for transesterification, they are not general as far asp-ketoesters are concerned. some of these methods used toxic, expensive reagents and in relatives large amount. inthis research, transesterification reaction six type...

2012
Pandiyan Sivakumar Pathmanban Sivakumar

Introduction The possibility of using vegetable oils as fuel has been documented in the beginning of diesel engines. Biodiesel produced from waste oil by trans-esterification process can be used as a substitute for diesel in internal combustion engines [1]. Biodiesel can be produced by the transesterifcation of vegetable oils [2] such as soyabean oil, rapeseed oil, sunflower oil etc. [3]. Trans...

2014
Monna Lisa Queiroz Bruna Onorevoli Gabriela Fontes Laiza Krause Heiddy Alvarez Cláudio Dariva Elina Caramão Alini Fricks

Introduction The fatty acid esters synthesis by transesterification of oils to produce biodiesel commonly involves methanol or ethanol as acyl acceptor. The transesterification of vegetable oils catalyzed by lipases is an alternative process for obtaining biodiesel. These biocatalysts working under mild conditions of temperature, allow for easy recovery of glycerol, synthesis of specific alkyl ...

A.R. Abbaspour P. Moaveni

Transesterification, one of the most effective methods for ester synthesis, is usually conducted under acid or basicconditions. Although quite a few methods have been reported for transesterification, they are not general as far asp-ketoesters are concerned. Some of these methods used toxic, expensive reagents and in relatives large amount. Inthis research, transesterification reaction six type...

Kambiz Tahvildari, Tahereh Hajy Heidar

Due to the high price of virgin vegetable oils and the drawbacks of the homogeneous catalytic transesterification, in this work an economically profitable alternative process was proposed for biodiesel synthesis in which transesterification of the low-cost waste cooking oil (WCO) with methanol in a heterogeneous system was done. Alumina impregnated with sodium hydroxide was utilized as a solid ...

2008
Mohamed M. Changalov Dimiter D. Petkov

The synthesis of four new peptidyl nucleosides is reported. The kinetic data obtained for the transesterification of 2'/3'-O-benzyloxycarbonyl-L-p-nitrophenylalanyl 5'-O-trityl ribonucleosides which contain different substituents at C position of the purine residue indicates for different mechanisms of the transesterification reaction. The peptidyl nucleosides with an amino group at C position ...

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...

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