scholarly journals Kinetics, Mechanism and Simulation of Hydrogen Transfer Reaction of α, β-Unsaturated Aldehydes to Allylic Alcohols

2021 ◽  
Author(s):  
Hui Guo ◽  
Yuchao Li ◽  
Cuncun Zuo ◽  
Yanxia Zheng ◽  
Xinpeng Guo ◽  
...  
Keyword(s):  
Density Functional ◽  
Hydrogen Transfer ◽  
Transfer Reaction ◽  
Catalytic Mechanism ◽  
Batch Reactor ◽  
Tubular Reactor ◽  
Transfer Reactions ◽  
Reflux Ratio ◽  
Hydrogen Transfer Reaction ◽  
Hydrogen Transfer Reactions

Homogeneous hydrogen transfer reactions of methacrolein (MAL) and isopropanol (IPA) to methallyl alcohol (MAA) were investigated in batch reactor (Conv.89%, Select 93.1%) and tubular reactor (Conv.88.1%, Select 95%) using aluminum isopropoxide (Al(OPri)3) as catalyst. Kinetic experiments on hydrogen transfer reactions and reaction order were investigated in batch reactor and tubular reactor. Response surface methodology (RAM) was applied to optimize the optimum reaction conditions of hydrogen transfer reaction. Purification process of MAA from product mixture after hydrogen transfer reaction was simulated with Aspen Plus software, theoretical stages, reflux ratio and feed stage of distillation tower were optimized. Density Functional Theory (DFT) was used to investigate viable reaction pathway and to probe the catalytic mechanism between reactants and catalyst, including dehydrogenation, coupling and hydrogenation reaction. Microscopic mechanisms of hydrogen transfer reaction from MAA to MAL were acquired in detail and could be easily extended to other series of hydrogen transfer reaction.

DENSITY FUNCTIONAL COMPUTATIONS OF Rh(I)-CATALYZED HYDROACYLATION OF ETHENE OR ETHYNE

2008 ◽  
Vol 07 (05) ◽  
pp. 1041-1053 ◽  
Author(s):  
JIGANG GAO ◽  
FEN WANG ◽  
QINGXI MENG ◽  
MING LI
Keyword(s):  
Density Functional ◽  
Hydrogen Transfer ◽  
Transfer Reaction ◽  
Functional Theory ◽  
Bond Forming ◽  
Hydrogen Transfer Reaction ◽  
Effect Of Solvent ◽  
Calculation Results ◽  
Released Energy ◽  
Density Functional Computations

Density functional theory has been used to study Rh(I) -catalyzed hydroacylation of ethene or ethyne. All the intermediates and the transition states were optimized completely at the B3LYP/6-311++G(d,p) level (LANL2DZ(d) for Rh , P). Calculation results confirm that Rh(I) -catalyzed hydroacylation of ethene is exothermic and the total released energy is -54 kJ/mol, and that Rh(I) -catalyzed hydroacylation of ethyne is also exothermic and the total released energy is -122 kJ/mol. In Rh(I) -catalyzed hydroacylation, ethene and ethyne have similar reactivity. Rh(I) -catalyzed oxidative addition of aldehyde is the rate-determinating step for the Rh(I) -catalyzed hydroacylation of ethene or ethyne. Hydrogen transfer reaction is prior to the C – C bond-forming reaction for Rh(I) -catalyzed hydroacylation of ethene. Thus hydrogen transfer reaction and the C – C bond-forming reaction may be co-existed for Rh(I) -catalyzed hydroacylation of ethyne. The effect of solvent in the hydroacylation of ethyne is greater than that in the hydroacylation of ethene.

scholarly journals Hydrogen Transfer Reactions of Carbonyls, Alkynes, and Alkenes with Noble Metals in the Presence of Alcohols/Ethers and Amines as Hydrogen Donors

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 671 ◽  
Author(s):  
Eszter Baráth
Keyword(s):  
Condensed Phase ◽  
Crucial Role ◽  
Noble Metals ◽  
Hydrogen Transfer ◽  
Transfer Reactions ◽  
Hydrogen Donors ◽  
Stereoselective Reactions ◽  
Present Summary ◽  
Industrial Relevance ◽  
Hydrogen Transfer Reactions

Hydrogen transfer reactions have exceptional importance, due to their applicability in numerous synthetic pathways, with academic as well as industrial relevance. The most important transformations are, e.g., reduction, ring-closing, stereoselective reactions, and the synthesis of heterocycles. The present review provides insights into the hydrogen transfer reactions in the condensed phase in the presence of noble metals (Rh, Ru, Pd) as catalysts. Since the H-donor molecules (such as alcohols/ethers and amines (1°, 2°, 3°)) and the acceptor molecules (alkenes (C=C), alkynes (C≡C), and carbonyl (C=O) compounds) play a crucial role from mechanistic viewpoints, the present summary points out the key mechanistic differences with the interpretation of current contributions and the corresponding historical achievements as well.

Sign in / Sign up

Export Citation Format

Share Document