Bifunctional Heterogeneous Catalysis of Silica-Alumina-Supported Tertiary Amines with Controlled Acid-Base Interactions for Efficient 1,4-Addition Reactions

2009 ◽  
Vol 15 (41) ◽  
pp. 10871-10879 ◽  
Author(s):  
Ken Motokura ◽  
Satoka Tanaka ◽  
Mizuki Tada ◽  
Yasuhiro Iwasawa
Keyword(s):  
Heterogeneous Catalysis ◽  
Addition Reactions ◽  
Tertiary Amines ◽  
Acid Base ◽  
Silica Alumina

Ionic dimerisation of trifluoropropenenitrile and its addition reactions with methyl trifluoropropenoate

1980 ◽  
Vol 45 (2) ◽  
pp. 406-414 ◽  
Author(s):  
Jiří Svoboda ◽  
Oldřich Paleta ◽  
Václav Dědek
Keyword(s):  
Reaction Mechanism ◽  
Proton Transfer ◽  
Substituent Effect ◽  
Solvent Molecule ◽  
Addition Product ◽  
Potassium Fluoride ◽  
Relative Reactivity ◽  
Addition Reactions ◽  
Tertiary Amines ◽  
Optimum Conditions

Dimerisation of trifluoropropenenitrile (I) in the presence of potassium fluoride and tertiary amines afforded a mixture of stereoisomeric perfluoro-4-methyl-pentenedinitriles (II), higher-boiling compounds, and 2,3,3,3-tetrafluoropropanenitrile (III) which arises by proton transfer from the solvent molecule. Under optimum conditions, product II was obtained in about 50% yield. Reaction of the nitrile I with methyl trifluoropropenoate (IV) gave, besides the dimers II and V, the product of addition of the nitrile I to the propenoate, IV, i.e. methyl 4-cyanoperfluoro-2-pentenoate (VI), and the addition product of the propenoate IV to the nitrile I, i.e. methyl 4-cyanoperfluoro-2-methyl-3-butenoate (VII). The relative reactivity if I and IV is discussed. The ratio of stereoisomers in II, V, VI and VII indicates that the magnitude of the steric substituent effect, operating in the reaction mechanism, decreases in the order -CFCF3.(COOCH3) > -CFCF3(CN) > -COOCH3 > -CN.

scholarly journals Atomic-level organization of vicinal acid–base pairs through the chemisorption of aniline and derivatives onto mesoporous SBA15

2016 ◽  
Vol 7 (9) ◽  
pp. 6099-6105 ◽  
Author(s):  
Bilel Hamzaoui ◽  
Anissa Bendjeriou-Sedjerari ◽  
Eva Pump ◽  
Edy Abou-Hamad ◽  
Rachid Sougrat ◽  
...  
Keyword(s):  
Heterogeneous Catalysis ◽  
Heterogeneous Catalysts ◽  
Atomic Level ◽  
Acid Base ◽  
Base Pairs ◽  
High Interest

The design of novel heterogeneous catalysts with multiple adjacent functionalities is of high interest to heterogeneous catalysis.

scholarly journals Neutral, cationic and anionic organonickel and -palladium complexes supported by iminophosphine/phosphinoenaminato ligands

2020 ◽  
Vol 49 (2) ◽  
pp. 322-335 ◽  
Author(s):  
Tomás G. Santiago ◽  
Carmen Urbaneja ◽  
Eleuterio Álvarez ◽  
Elena Ávila ◽  
Pilar Palma ◽  
...  
Keyword(s):  
Ligand Exchange ◽  
Oxidative Addition ◽  
Palladium Complexes ◽  
Addition Reactions ◽  
Acid Base

Ligand exchange and oxidative addition reactions allow the synthesis of Ni(ii) and Pd(ii) complexes with deprotonable iminophosphine ligands. The acid–base behavior of iminophosphine ligands coordinated to organometallic Ni(ii) fragments is analyzed.

Development of a gas chromatograph-mass spectrometer with ‘on-line’ computer for studies in catalysis. Reactions of ethylene and deuterium on oxides

1974 ◽  
Vol 338 (1614) ◽  
pp. 299-310 ◽  
Keyword(s):  
Zinc Oxide ◽  
Heterogeneous Catalysis ◽  
Magnesium Oxide ◽  
Chromium Oxide ◽  
Rate Constants ◽  
High Selectivity ◽  
Addition Reactions ◽  
Gas Chromatograph ◽  
On Line ◽  
Catalytic Behaviour

The development of an ‘on-line’ computer for use with a combined gas chromatographymass spectroscopy (g.c.-m.s.) technique in the study of heterogeneous catalysis is described and discussed with reference to the reactions of ethylene and deuterium on oxides. Emphasis has been placed on the selectivities shown by a number of catalysts for the exchange and addition reactions. Magnesium oxide effects the exchange of ethylene without production of ethane even at 671 K; y-alumina also exhibits a high selectivity for exchange. In contrast, on chromium oxide (Cr20 3) at 197 K and zinc oxide at 273 K, ethylene undergoes rapid deuteration with no observable exchange of the olefin. For the range of catalysts studied the ratio of rate constants for the exchange and addition reactions decreases in the order: MgO > Al 2 O 3 > TiO 2 ~ Fe 2 O 3 > Co 3 O 4 > ZrO 2 > ZnO ~ Cr 2 O 3 . An explanation for the marked differences in catalytic behaviour within this group of oxides is provided.

scholarly journals Lewis acid–base 1,2-addition reactions: synthesis of pyrylium borates from en-ynoate precursors

2016 ◽  
Vol 45 (14) ◽  
pp. 5929-5932 ◽  
Author(s):  
Lewis C. Wilkins ◽  
Hugh B. Hamilton ◽  
Benson M. Kariuki ◽  
A. Stephen K. Hashmi ◽  
Max M. Hansmann ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Addition Reactions ◽  
Acid Base ◽  
Strong Lewis Acid

Treatment of methyl (Z)-2-alken-4-ynoates with the strong Lewis acid tris(pentafluorophenyl) borane, B(C6F5)3, yield 2,5,6-substituted zwitterionic pyrylium borate species via an intramolecular 6-endo-dig cyclisation reaction.

Coordination Chemistry of N,N′-Bis(diphenylphosphanylmethyl)- 2,3-dihydro-1H-perimidine – Lewis Acid-Base Complexes with the d10-Metals Nickel(0) and Gold(I)

2014 ◽  
Vol 69 (11-12) ◽  
pp. 1299-1305 ◽  
Author(s):  
Sven Krieck ◽  
Daniel Schulze ◽  
Helmar Görls ◽  
Matthias Westerhausen
Keyword(s):  
Coordination Chemistry ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Lewis Acid ◽  
Nickel Complexes ◽  
Nickel Atom ◽  
Addition Reactions ◽  
Acid Base ◽  
Tetrahedral Environment

Abstract The addition reactions of N,N′-bis(diphenylphosphanylmethyl)-2,3-dihydro-1H-perimidine (1) with [(cod)2Ni] and [(Ph3P)AuCl] yield yellow [(1)Ni(η4-cod)] (2) and colorless [(1)(Ph3P)AuCl]·3MeOH (3), respectively. In these transition metal complexes of nickel(0) and gold(I) 1 acts as a bidentate chelating ligand. Crystal structures of [(1)Ni(η4-cod)]·3THF (2a) and of cosolvent-free [(1)Ni(η4-cod)] (2) reveal a distorted tetrahedral environment of the nickel atom. The gold(I) atom in 3 exhibits a very long Au-Cl bond of 296.2(1) pm. In contrast to the nickel complexes, compound 3 shows strong agostic interactions between gold(I) and a methylene fragment.

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