Results 81 to 90 of about 18,682 (226)

Determinação de coeficiente de difusão de esteres e reações de transesterificação catalisadas por enzimas imobilizadas em organo-gel [PDF]

, 1994
Dissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas.Neste trabalho, foi estudado o grau de impedimento imposto pelas barreiras difusionais de ésteres quando estes passam do meio reacional para o gel e
João, Jair Juarez
core  

C‐Terminal Functionalization Methods of Amino Acids, Peptides, and Proteins

Chemistry – A European Journal, EarlyView.
C‐terminal functionalization offers powerful routes to peptide and protein diversification, yet epimerization, hydrolysis, and selectivity remain key challenges. This Review surveys enzymatic, decarboxylative, and condensation strategies, highlighting advances toward chemo‐ and regioselective, protecting‐group‐free, atom‐efficient methods applicable to
Jay Hanssens, Mark Lambers, Romano V. A. Orru, Jordy M. Saya   +3 more
wiley   +1 more source

Étude comparative des procédés de la transestérification assistée par microonde des huiles végétales et usagées en milieu liquides ioniques

, 2016
65 p. : ill. ; 30 cmCe travail s’inscrit dans le domaine de la valorisation énergétique des déchets agroalimentaires dont l’huile usagée en fait partie et l’utilisation des écotechnologies (irradiation microonde en présence des liquides ioniques).
Benerab, Noureddine
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Aptitude à la transestérification de quelques lipases régiosélectives 1-3. II. Taux de conversion et glycérides partiels en fonction de l'activité de l'eau des biocatalyseurs [PDF]

, 1988
La mise au point des réactions d'interestérification biocatalysées en milieu fondu par des lipases régiosélectives 1-3, sélectionnées précédemment pour leur activité de transestérification, nécessite d'étudier l'influence de l'activité de l'eau.
Graille, Jean, Muderhwa, J.M., Pina, Michel   +2 more
core  

Polycarbonate Upcycling Into Block Copolymers via Transcarbonation: Influence of the Catalyst on the Microstructure

Chemistry – A European Journal, EarlyView.
Upcycling of polycarbonate (PC‐BPA) into PC‐BPA–polybutadiene (PBd) block copolymers was achieved by transcarbonation with hydroxytelechelic PBd (Krasol) using organic base catalysts. Catalyst choice governed conversion, molecular weight and microstructure: TBD produced multiblock copolymers, whereas DMAP yielded higher Mn materials with lower ...
N. Kanso, M. Bria, A. Favrelle‐Huret, G. Stoclet, W. Thielemans, P. Zinck   +5 more
wiley   +1 more source

Experimental methods in chemical engineering: Temperature‐programmed desorption—TPD

The Canadian Journal of Chemical Engineering, EarlyView.
Abstract Temperature‐programmed desorption (TPD) characterizes the surface active sites of functional materials, such as adsorbents (metal hydrides, porous carbons, zeolites, metal–organic frameworks, for example) and catalysts. Solids surfaces are pre‐treated to remove moisture, contaminants, and previously adsorbed species, then a probe molecule (NH3$
Daniel A. Valdivieso‐Vera, Gregory S. Patience, M. Olga Guerrero‐Pérez   +2 more
wiley   +1 more source

Environmental and economic sustainability assessment of biofuels from valorising spent coffee grounds

Cleaner Environmental Systems
This study quantifies and compares the life cycle environmental and economic sustainability of five most common and widely researched valorisation routes for spent coffee grounds (SCGs): i) fuel pelletizing; ii) combination of transesterification and ...
Piya Gosalvitr, Rosa M. Cuéllar-Franca, Robin Smith, Adisa Azapagic   +3 more
doaj   +1 more source

A lumped modelling framework for the epoxidation of vegetable oils and fatty acid methyl esters

The Canadian Journal of Chemical Engineering, EarlyView.
Abstract Epoxidized vegetable oils and fatty acid methyl esters are promising bio‐based alternatives to phthalates for plasticizer applications. Their synthesis typically involves the reaction of unsaturated double bonds with peracetic acid in a biphasic liquid–liquid system, where the simultaneous occurrence of reaction and phase partitioning makes ...
Irene Presti, Carlo Pirola, Francesco Megna, Federico Galli   +3 more
wiley   +1 more source

KINETICS OF PALM OIL TRANSESTERIFICATION IN METHANOL WITH POTASSIUM HYDROXIDE AS A CATALYST

Indonesian Journal of Chemistry, 2010
A study on palm oil transesterification to evaluate the effect of some parameters in the reaction on the reaction kinetics has been carried out. Transesterification was started by preparing potassium methoxide from potassium hydroxide and methanol and ...
Yoeswono Yoeswono, Triyono Triyono, Iqmal Tahir   +2 more
doaj   +1 more source

Schülerexperimente zur Synthese naturidentischer, geruchsaktiver Ester im Mikromaßstab durch alkalisch katalysierte Umesterung von Glyceriden

CHEMKON, EarlyView.
In diesem Beitrag wird ein einfaches Schülerexperiment vorgestellt, bei dem durch Umesterung von Triacylglyceriden mit n‐Alkanolen im Mikromaßstab geruchsaktive Alkylalkanoate hergestellt werden. Die Reaktion erfolgt alkalisch katalysiert bei Raumtemperatur in kleinen Gefäßen; es entstehen flüchtige Ester mit charakteristischen Frucht‐ und ...
Horst Klemeyer
wiley   +1 more source