tailieunhanh - Mechanism and rate constant of proline-catalysed asymmetric aldol reaction of acetone and p-nitrobenzaldehyde in solution medium: Density-functional theory computation

In search of new ways to improve catalyst design, the current research focused on using quantum mechanical descriptors to investigate the effect of proline as a catalyst for mechanism and rate of asymmetric aldol reaction. A plausible mechanism of reaction between acetone and 4-nitrobenzaldehyde in acetone medium was developed using highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies calculated via density functional theory (DFT) at the 6-31G⁄/ B3LYP level of theory. New mechanistic steps were proposed and found to follow, with expansion, the previously reported iminium-enamine route of typical class 1 aldolase enzymes. From the elementary steps, the first step which involves a bimolecular collision of acetone and proline was considered as the rate-determining step, having the highest activation energy of kJ mol 1 . The mechanism was used to develop the rate law from which the overall rate constant was calculated and found to be 4:04 10 8 d m3 mol 1 s 1. The new mechanistic insights and the explicit computation of the rate constant further improve the kinetic knowledge of the reaction. | Mechanism and rate constant of proline-catalysed asymmetric aldol reaction of acetone and p-nitrobenzaldehyde in solution medium: Density-functional theory computation

• Hoá học
• Mechanism and rate constant
• Proline catalysed asymmetric aldol reaction
• P nitrobenzaldehyde in solution medium
• Density functional
• Theory computation
• Theory of Computation
• Lecture Theory of Computation
• Post correspondence problem
• Computable functions
• Turing machines
• Model of computation
• Discrete mathematics
• Modeling computation
• Number theory
• Advanced counting techniques
• Finite state machines
• Complexity theory
• Godel’s incompleteness theorem
• Argue mathematically
• Automata theory
• Turing machine
• Transition function
• Special blank symbol
• State diagram
• The yields relation
• Rejection configurations
• Designing TMs
• Transition diagram of the Turing Machine
• Multi tape Turing machine
• Variants of Turing machines
• k tape TMs
• Study enumerators
• Equivalent single tape TM
• Definition of algorithm
• The Church Turing thesis
• Hilbert’s 10th problem
• Matijasevic’s theorem
• Decidable languages
• Regular languages
• Context free languages
• The Halting problem
• Universal Turing machine
• Galilean paradox
• Cantor diagonalization
• Halting problem
• Co Turing recognizability
• Universal Turning machine
• Turing un recognizable language
• Linear bounded automata
• Acceptance problem for LBAs
• Emptiness problem for LBAs
• Russell’s paradox
• Acceptance problem for TMs
• Reducibility and un Turing recognizability
• Reducibility diagram
• Undecidable language
• un Turing recognizability
• Programs that print themselves
• Recursion theorem
• Programming languages version
• Logical theories
• Scrambles programs
• Decidability of logical theories
• Presburger arithmetic
• Decidability of presburger arithmetic
• Undecidability of logical theories
• Peano arithmetic
• Undecidability of peano arithmetic
• Gödel’s incompleteness theorem
• Oracle turing machines
• Turing reducibility
• Berry paradox
• Minimal length descriptions
• Descriptive complexity
• Kolmogorov complexity
• Kolmogorov Chaitin complexity
• Incompressible strings
• Big O notation
• Big Oh notation
• Little o notation
• Time complexity classes
• Non deterministic TMs
• Non deterministic time
• Deterministic single tape machines
• Polynomial time algorithm
• Polynomial time verifiers
• Non deterministic TM
• Non deterministic polynomial time algorithm
• Verification algorithms
• Cook Levin theorem
• Polynomial time reducibility
• NP completeness