Rapid transmethylation of microgram amounts of phosphatidylcholine on potassium methoxide/celite columns1,2,3

William N. Marmer

doi:10.1007/bf02533836

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

Indonesian Journal of Chemistry ◽

10.22146/ijc.21625 ◽

2010 ◽

Vol 8 (2) ◽

pp. 219-225

Author(s):

Yoeswono Yoeswono ◽

Triyono Triyono ◽

Iqmal Tahir

Keyword(s):

Activation Energy ◽

Palm Oil ◽

Rate Constants ◽

Potassium Hydroxide ◽

Catalyst Concentration ◽

Time Interval ◽

Pseudo First Order Reaction ◽

Exponential Factor ◽

Potassium Methoxide ◽

First Order

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 then mixed it with the palm oil. An aliquot was taken at certain time interval during transesterification and poured into test tube filled with distilled water to stop the reaction immediately. The oil phase that separated from the glycerol phase by centrifugation was analyzed by 1H-NMR spectrometer to determine the percentage of methyl ester conversion. Temperature and catalyst concentration were varied in order to determine the reaction rate constants, activation energies, pre-exponential factors, and effective collisions. The results showed that palm oil transesterification in methanol with 0.5 and 1 % w/w KOH/palm oil catalyst concentration appeared to follow pseudo-first order reaction. The rate constants increase with temperature. After 13 min of reaction, More methyl esters were formed using KOH 1 % than using 0.5 % w/w KOH/palm oil catalyst concentration. The activation energy (Ea) and pre-exponential factor (A) for reaction using 1 % w/w KOH was lower than those using 0.5 % w/w KOH. Keywords: palm oil, transesterification, catalyst, first order kinetics, activation energy, pre-exponential factor

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Structure of the potassium methoxide adduct of s-trinitrobenzene, a Meisenheimer complex

Acta Crystallographica Section B ◽

10.1107/s0567740879004593 ◽

1979 ◽

Vol 35 (3) ◽

pp. 733-736 ◽

Cited By ~ 25

Author(s):

R. Destro ◽

T. Pilati ◽

M. Simonetta

Keyword(s):

Potassium Methoxide

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Electrophilic substitution at saturated carbon. XXXVI. Correlations between rates of potassium methoxide catalyzed hydrogen-deuterium exchange reactions of carbon acids and H

Journal of the American Chemical Society ◽

10.1021/ja01009a019 ◽

1968 ◽

Vol 90 (7) ◽

pp. 1784-1791 ◽

Cited By ~ 8

Author(s):

Willy D. Kollmeyer ◽

Donald J. Cram

Keyword(s):

Electrophilic Substitution ◽

Deuterium Exchange ◽

Hydrogen Deuterium Exchange ◽

Exchange Reactions ◽

Potassium Methoxide ◽

Hydrogen Deuterium ◽

Carbon Acids

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Alkoxide-catalyzed addition of alkyl carbonates across alkynes – stereoselective synthesis of (E)-β-alkoxyacrylates

Green Chemistry ◽

10.1039/c6gc03168d ◽

2017 ◽

Vol 19 (3) ◽

pp. 643-646

Author(s):

Timo Wendling ◽

Eugen Risto ◽

Benjamin Erb ◽

Lukas J. Gooßen

Keyword(s):

Stereoselective Synthesis ◽

Terminal Alkynes ◽

Potassium Methoxide ◽

Stereoselective Addition

Terminal alkynes were converted to (E)-β-alkoxyacrylates via regio- and stereoselective addition of dialky carbonates catalyzed by potassium methoxide.

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2,4-Diazapentadienes. II. A Carbanion Cyclization

Canadian Journal of Chemistry ◽

10.1139/v72-105 ◽

1972 ◽

Vol 50 (5) ◽

pp. 678-689 ◽

Cited By ~ 20

Author(s):

D. H. Hunter ◽

S. K. Sim

Keyword(s):

Isotope Effect ◽

Solvent Effects ◽

Isotope Effects ◽

Substituent Effects ◽

Deuterium Exchange ◽

Hydrogen Deuterium Exchange ◽

Deuterium Isotope Effect ◽

Potassium Methoxide ◽

Proton Shift ◽

Hydrogen Deuterium

The mechanism of the cyclization and 1,3-proton shift of 1,3,5-triaryl-2,4-diaza-1,3-pentadienes (1) catalyzed by phenyllithium and by potassium methoxide–methanol has been studied. On the basis of substituent effects, hydrogen–deuterium exchange, isotope effects, and solvent effects, it was deduced that both the cyclization and prototropy involve a common W-shaped carbanion which rapidly cyclizes. A kinetic deuterium isotope effect of 2 was calculated for protonation of this intermediate carbanion in methanol.

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