Formation of A-type anthocyanin-epicatechin dimers by model reactions of anthocyanin extracts and epicatechin

LWT ◽  
2021 ◽  
Vol 146 ◽  
pp. 111475
Author(s):  
Wei Li ◽  
Jiahao Yu ◽  
Jian Zhang ◽  
Lianfu Zhang
Keyword(s):  
Model Reactions

Model reactions for the study of hydrogenation and acidic activity of palladium catalysts

1987 ◽  
Vol 52 (8) ◽  
pp. 2019-2027 ◽  
Author(s):  
Libor Červený ◽  
Nguyen Thi Du ◽  
Ivo Paseka
Keyword(s):  
Palladium Catalysts ◽  
Styrene Oxide ◽  
Side Reactions ◽  
Pd Catalysts ◽  
Variable Parameters ◽  
Acid Properties ◽  
Liquid Phase Hydrogenation ◽  
Acid Catalysed Reactions ◽  
Different Content ◽  
Model Reactions

Palladium catalysts have been used to study the hydrogenation of 1-phenyl-2-butene-1-ol which is accompanied by several side reactions considered to be acid-catalysed. Another model reaction studied was dehydration and subsequent hydrogenation or hydrogenolysis of 1-phenyl-1,3-propanediol to 3-phenyl-1-propanol, accompanied by formation of propylbenzene. The dehydration and propylbenzene formation can be again classified as acid-catalysed reactions. Another one is methanolysis of styrene oxide taking place under conditions of liquid phase hydrogenation due to the acid properties of Pd-H systems. Hydrogenation activity of Pd catalysts was tested by hydrogenation of cyclohexene. Sixteen Pd catalysts on different supports and with different content of active component were used, their activity and selectivity was determined and the effect of variable parameters in the synthesis of these catalysts on the activity and selectivity is discussed.

Pore-expanded SBA-15 for the immobilization of a recombinant Candida antarctica lipase B: Application in esterification and hydrolysis as model reactions

2018 ◽  
Vol 129 ◽  
pp. 12-24 ◽  
Author(s):  
Nathalia Saraiva Rios ◽  
Maisa Pessoa Pinheiro ◽  
Magno Luís Bezerra Lima ◽  
Denise Maria Guimarães Freire ◽  
Ivanildo José da Silva ◽  
...  
Keyword(s):  
Candida Antarctica ◽  
Candida Antarctica Lipase B ◽  
Candida Antarctica Lipase ◽  
Lipase B ◽  
Model Reactions

Dissecting transmetalation reactions at the molecular level: C–B versus F–B bond activation in phenyltrifluoroborate silver complexes

2021 ◽  
Vol 50 (4) ◽  
pp. 1496-1506
Author(s):  
Fiona Bathie ◽  
Adam W. E. Stewart ◽  
Allan J. Canty ◽  
Richard A. J. O'Hair
Keyword(s):  
Gas Phase ◽  
Bond Activation ◽  
Molecular Level ◽  
Silver Complexes ◽  
Fundamental Model ◽  
Model Reactions

Gas-phase experiments and computation provide fundamental model reactions for aryl and fluoride transfer between silver and boron centres.

Capping of Living Polystyryl Cations with Ditolylethylene:  Model Reactions with Dimeric Cations

1999 ◽  
Vol 32 (9) ◽  
pp. 2883-2888 ◽  
Author(s):  
Philip L. Canale ◽  
Rudolf Faust
Keyword(s):  
Model Reactions

Improved lifetime and stability of copper species in hierarchical, copper-incorporated CuSAPO-34 verified by catalytic model reactions

2021 ◽  
Author(s):  
Guro Sørli ◽  
Muhammad Mohsin Azim ◽  
Magnus Ronning ◽  
Karina Mathisen
Keyword(s):  
Absorption Spectroscopy ◽  
Mesoporous Structure ◽  
Single Site ◽  
Pluronic F127 ◽  
Structure Directing Agent ◽  
Copper Species ◽  
X Ray ◽  
X Ray Absorption ◽  
Model Reactions

The first successful synthesis of hierarchical CuSAPO-34 (3.9 wt.% Cu) is reported using the polymer Pluronic F127 as mesoporous structure directing agent (SDA). X-ray absorption spectroscopy (XAS) proved single site...

Pentacarbonylmanganese enolate and dienolate complexes. Preparative and mechanistic considerations

1990 ◽  
Vol 68 (3) ◽  
pp. 492-501 ◽  
Author(s):  
Andrew P. Masters ◽  
Ted S. Sorensen
Keyword(s):  
Nmr Spectroscopy ◽  
Nucleophilic Substitution ◽  
Reaction Products ◽  
Organic Products ◽  
Mechanism Of The Reaction ◽  
Model Reactions ◽  
Inorganic And Organic

Reactions of pentacarbonyl manganate anion with 4-halocrotonate esters or 2-halocarboxylate esters result in a complex set of inorganic and organic products, usually including the expected dienolate (or enolate) complexes. The reaction variables include the counterion, solvent, and halo group. The mechanism of the reaction has been investigated by conducting a thorough characterization of the reaction products under various conditions and also by carrying out model reactions. One can rationalize most of the non-organometallic products using either a radical or carbanion mechanism, but the latter seems to fit the available data better. Experimental procedures for optimizing the yield of the organometallic dienolate or enolate complexes have been worked out. Keywords: pentacarbonyl manganate, metalate nucleophilicity, enolate complex, nucleophilic substitution, 55Mn NMR spectroscopy.

Deacylation of Fluorine-substituted trans-Cinnamoyl-α-chymotrypsins

1975 ◽  
Vol 53 (4) ◽  
pp. 513-518 ◽  
Author(s):  
J. T. Gerig ◽  
R. S. McLeod
Keyword(s):  
Rate Constants ◽  
Rate Effect ◽  
Ionization State ◽  
Hydrolysis Rates ◽  
Order Of Magnitude ◽  
Model Reactions

Deacylation of unsubstituted and of o-F-, m-F, p-F, α-F, pentafluoro-, p-methyl-, and p-trifluoromethyl-substituted trans-cinnamoyl- α-chymotrypsins has been studied from pH 4 to 8. The deacylation rate constants were found to depend upon the ionization state of a group on the enzyme with an apparent pK in the range 6.3–7.3. The hydrolysis rates of the correspondingly substituted p-nitrophenylcinnamate esters were determined at pH 10.6. Correlation of the data for these model reactions with the corresponding rates of enzyme deacylation suggests that the p-methyl-substituted acylenzyme is about an order of magnitude more reactive than expected while p-trifluoromethyl substitution results in deacylation at a rate 10 times slower than expected. The remaining substituents exert about the anticipated rate effect on deacylation.

Biochemical Model Reactions for Cataract Research

1985 ◽  
Vol 17 (5) ◽  
pp. 302-307 ◽  
Author(s):  
Erich F. Elstner ◽  
R. Adamczyk ◽  
A. Furch ◽  
R. Kröner
Keyword(s):  
Biochemical Model ◽  
Model Reactions
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