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Understanding the influence of Lewis acids in the regioselectivity of the Diels-Alder reactions of 2-methoxy-5-methyl-1,4-benzoquinone: A DFT study
(2009)
The mechanisms of the Diels-Alder (DA) reactions of 2-methoxy-5-methyl-1,4-benzoquinone 1 with 2-methyl-1,3-butadiene 2, in the absence and in the presence of LA catalysts, have been studied using the DFT method at the ...
Bronsted Acid Catalyzed Morita-Baylis-Hillman Reaction: A New Mechanistic View for Thioureas Revealed by ESI-MS(/MS) Monitoring and DFT Calculations
(Wiley-v C H Verlag Gmbh, 2009-01-01)
A Morita-Baylis-Hillman (MBH) reaction catalyzed by thiourea was monitored by ESI-MS(/MS) and key intermediates were intercepted and characterized. These intermediates Suggest that thiourea acts as an organocatalyst in all ...
Bronsted Acid Catalyzed Morita-Baylis-Hillman Reaction: A New Mechanistic View for Thioureas Revealed by ESI-MS(/MS) Monitoring and DFT Calculations
(Wiley-v C H Verlag Gmbh, 2009-01-01)
A Morita-Baylis-Hillman (MBH) reaction catalyzed by thiourea was monitored by ESI-MS(/MS) and key intermediates were intercepted and characterized. These intermediates Suggest that thiourea acts as an organocatalyst in all ...
Relationship between basicity and nucleophilicity
(2007)
The empirical concepts of basicity and nucleophilicity are related but not strictly proportional. Hence, the aim of this study is to help in elucidating the range where both concepts are directly proportional. To do this, ...
Relationships between the third-order reactivity indicators in chemical density-functional theory
(AMER INST PHYSICS, 2009)
Relationships between third-order reactivity indicators in the closed system [N, v(r)], open system [mu, v(r)], and density [rho(r)] pictures are derived. Our method of derivation unifies and extends known results. Among ...
Acid-base properties and active site requirements for elimination reactions on alkali-promoted MgO catalysts
(Elsevier Science, 2000-12)
Base-catalyzed elimination reactions were studied on MgO and alkali-modified MgO catalysts using 2-propanol as a probe reactant. The effect of the acid–base properties on the catalyst activity and selectivity was investigated ...
Reações ácido-base: conceito, representação e generalização a partir das energias envolvidas nas transformaçõesAcid-base reactions: concept, representation and generalization from the energy involved in transformations
(Sociedade Brasileira de Química, 2012)
Undergraduate students on the first year of Chemistry Courses are unfamiliar with the representation of acid-base reactions using the ionic equation H+ + OH- → H2O. A chemistry class was proposed about acid-base ...
Insights on the catalytic behaviour of sulfonic acid-functionalized ionic liquids (ILs) in transesterification reactions - voltammetric characterization of sulfonic task-specific ILs with bisulfate anions
(Royal Society of Chemistry, 2021-01)
This work shows for the first time the link between the amount of free sulfuric acid (as detected by cyclic voltammetry) and the activity of sulfonic-acid-functionalized ionic liquids (ILs) as acid catalysts for a ...
Kinetic of liquid-phase reactions catalyzed by acidic resins: The formation of peracetic acid for vegetable oil epoxidation
(Elsevier Science, 2000-05)
A heterogeneous kinetic model which takes into account the complete physicochemical interaction of reactive species in a polar liquid phase with an ion-exchange resin acting both as selective sorbent and heterogeneous ...