Search results for "Esterification"
showing 10 items of 71 documents
Über die polykondensation von diäthylphosphit mit aliphastischen diolen
1973
Die Umesterungsreaktion von Diathylphosphit mit linearen Diolen HO–(CH2)x–OH (x = 2–6 und 8) wurde untersucht. Ihre Bilanz zeigte, das neben der angestrebten Umesterungsreaktion in teilweise sehr erheblichem Umfang auch Atherstrukturen gebildet werden. Diese bis jetzt in diesem Zusammenhang noch nicht beschriebene Reaktion verlauft sehr wahrscheinlich im Sinn einer direkten Alkylierung der alkoholischen OH-Gruppen durch die Phosphitestergruppen, denn sie erfordert keinen Katalysator. Die Estergruppen gehen dabei in saure P-OH-Gruppen uber, die unter den angewendeten Bedingungen nicht mehr ohne weiteres zur Kondensation mit den Diolen befahigt sind. Das Verhaltnis von unerwunschter Atherbild…
Recovery of aliphatic low-molecular-mass carboxylic acids from hardwood kraft black liquor
2015
Abstract During alkaline pulping of wood, substantial amounts of carbohydrates-derived aliphatic carboxylic acids (formic and acetic acids together with various hydroxy acids) are formed and dissolved into the cooking liquor (“black liquor”). These acids with low heating values are considered to be potential feedstocks for the chemical industry but, due to many factors, their straightforward recovery as free acids from black liquor (pH 13–14) is difficult. In this paper, we outlined the partial recovery of volatile formic and acetic acids from the acidified birch ( Betula pendula ) kraft black liquor (pH approximately 2.5) by distillation, and the partial recovery of significant low-molecul…
Microwave-Assisted Esterification of Tall Oil Fatty Acids with Methanol Using Lignin-Based Solid Catalyst
2016
During alkaline pulping significant amounts of lignin, carbohydrates (mostly hemicelluloses), and extractives (tall oil soap and turpentine) are removed from wood feedstock. In this study, the catalytic esterification of fatty acids in tall oil with methanol to produce fatty acid methyl esters under microwave irradiation was performed at 100 °C for 10–60 min. A novel heterogeneous acid catalyst tested for this purpose was synthesized from the hardwood alkali lignin that was precipitated by acidification from the black liquor from soda-AQ pulping. The comparative reaction data were obtained by using other solid catalysts, Amberlyst 15, and p-toluenesulfonic acid. The results showed the highe…
CCDC 1523875: Experimental Crystal Structure Determination
2017
UDARID : ethyl N-benzoylalaninate Space Group: P212121, Cell: a 5.2938(2)Å b 12.1920(8)Å c 17.7130(4)Å, α 90° β 90° γ 90° Work published 2017 via Cambridge Crystallographic Data Centre.
Effect of lithium ions on the catalytic efficiency of calcium oxide as a nanocatalyst for the transesterification of lard oil
2019
The present work encompasses the effect of Li+ ions on CaO nanoparticles for the transesterification of lard oil. The modification of CaO nanoparticles was achieved by the impregnation of different molar ratios of lithium hydroxide. Later, each catalyst was screened for the catalytic conversion of lard oil to a fatty acid methyl ester (FAME). The nanocatalyst CaO–0.5LiOH (1 : 0.5 molar ratio) showed the best conversion rate for FAME. The synthesized nanocatalyst was characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) analysis, and Hammett indicato…
Biodiesel via in situ wet microalgae biotransformation: Zwitter-type ionic liquid supported extraction and transesterification
2017
The production of biodiesel derived from microalgae is among the most forthcoming technologies that provide an ecologic alternative to fossil fuels. Herein, a method was developed that enables the direct extraction and conversion of algal oil to biodiesel without prior isolation. The reaction occurs in aqueous media catalyzed by immobilized Candida antarctica lipase B (Novozyme 435). Zwitter-type ionic liquids were used as cocatalyst to improve the selectivity and reactivity of the enzyme. In a model reaction with sunflower oil, 64% biodiesel was obtained. Applying this method to a slurry of whole-cell Chlorella zof ingiensis in water resulted in 74.8% of lipid extraction, with 27.7% biotra…
Application of Potassium Ion Impregnated Titanium Dioxide as Nanocatalyst for Transesterification of Linseed Oil
2018
The current work comprises the investigation of biodiesel production from linseed oil using TiO2 and a potassium L-tartrate monobasic (C4H5KO6)-modified TiO2 nanocatalyst. Different amounts of C4H5KO6 were considered for TiO2 modification. The nanocatalyst TiO2–0.5C4H5KO6 (1:0.5 molar ratio) showed the best conversion rate for biodiesel production. The nanocatalyst was characterized by FTIR, XRD, TEM, BET, and XPS, and the Hammett indicator–benzenecarboxylic acid titration method was used for basicity measurement. The biodiesel was characterized by GC-MS and 1H and 13C NMR. Furthermore, the optimum reaction parameters for transesterification reaction were analyzed, and the yield was determi…
Imidazolium-2-carboxylate as an afficient, expeditious and eco-friendly organocatalyst for glycerol carbonate synthesis
2009
An improved and greener approach towards the synthesis of glycerol carbonate, via transesterification, using 1-n-butyl-3-methylimidazolium-2-carboxylate as catalyst is described. The catalyst loading as low as 1% was sufficient to yield quantitative conversions. A plausible mechanism is proposed for the catalytic cycle leading to product formation.
Enhanced Heterogeneous Catalytic Conversion of Furfuryl Alcohol into Butyl Levulinate
2014
We study the catalytic condensation of furfuryl alcohol with 1-butanol to butyl levulinate. A screening of several commercial and as-synthesized solid acid catalysts shows that propylsulfonic acid-functionalized mesoporous silica outperforms the state-of-the-art phosphotungstate acid catalysts. The catalyst is prepared via template-assisted sol-gel polycondensation of TEOS and MPTMS. It gives 96 % yield (and 100 % selectivity) of butyl levulinate in 4h at 110 °C. Reaction profiles before and after a hot filtration test confirm that the active catalytic species do not leach into the solution. The catalyst synthesis, characterization, and mode of operation are presented and discussed. Sour ca…
Catalytic Activity of Char Obtained from Fast Pyrolysis in Esterification Reactions
2021
In this study different pathways for obtaining activated carbon with catalytical activity were analysed. Industrially fast pyrolysis is an efficient way of lignocellulosic biomass processing, since in this process various important high value chemicals are obtained. Biochar is obtained as the by-product in fast pyrolysis process from which activated carbon can be acquired with further chemical activation. Different methods for chemical activation of biochar were tested with the obtained activated charcoals being used as a catalyst in esterification reactions to evaluate their potential use as a heterogenic catalyst. Highest catalytical activity was observed when biochar was pre-treated with…