Rehybridization as a general mechanism for maximizing chemical and supramolecular bonding and a driving force for chemical reactions

2006 ◽  
Vol 28 (1) ◽  
pp. 373-390 ◽  
Author(s):  
Igor V. Alabugin ◽  
Mariappan Manoharan
Keyword(s):  
Chemical Reactions ◽  
Driving Force ◽  
General Mechanism

GALVANIC CELLS AND THE DRIVING FORCE OF CHEMICAL REACTIONS

1968 ◽  
pp. 282-308
Author(s):  
AMOS TURK ◽  
HERBERT MEISLICH ◽  
FRANK BRESCIA ◽  
JOHN ARENTS
Keyword(s):  
Chemical Reactions ◽  
Driving Force ◽  
Galvanic Cells

Syneresis in Silica Gel

1988 ◽  
Vol 121 ◽  
Author(s):  
George W. Scherer
Keyword(s):  
Fluid Flow ◽  
Sample Size ◽  
Silica Gel ◽  
Chemical Reactions ◽  
Driving Force ◽  
Viscoelastic Behavior ◽  
Accurate Representation ◽  
Flow Through ◽  
Kinetics Of ◽  
Gel Network

ABSTRACTThe driving force for syneresis is generally attributed to the same chemical reactions that produce gelation, but it has also been proposed that shrinkage could be driven by interracial energy. The latter possibility is explored and discounted. The kinetics of syneresis depend on the driving force, the mobility of the gel network, and the rate of fluid flow through the contracting gel. A model that allows for viscoelastic behavior of the gel and fluid flow according to Darcy's law is shown to provide a quantitatively accurate representation of the shape of the shrinkage curves and the dependence of the shrinkage rate on sample size.

scholarly journals Sonochemistry: Non-Classical Way of Synthesis

2019 ◽  
Vol 9 (6-s) ◽  
pp. 229-232
Author(s):  
Pintu Prajapati ◽  
Avani Sheth ◽  
Dhaval M Patel ◽  
Advaita Patel ◽  
Priti Mehta
Keyword(s):  
Chemical Synthesis ◽  
Chemical Reactions ◽  
Chemical Reaction ◽  
Driving Force ◽  
Current Knowledge ◽  
Theoretical Background ◽  
Green Approach ◽  
Ultrasound Assisted ◽  
Viable Approach ◽  
Detailed Picture

This review presents the detailed picture of current knowledge on ultrasound assisted chemical reactions and its green approach in chemical synthesis. This article illustrates the theoretical background and details about ultrasound, its mechanism (cavitation, the driving force) in chemical synthesis, types of reactions with different systems and its utility. All the reported applications have shown that Sonochemistry, ultrasound assisted chemical reaction is a green and economical viable approach for drug, impurity or chemical intermediate synthesis. Keywords: Cavitation, Sonocatalysis, Sonochemistry Ultrasound

scholarly journals The Second Law Of Thermodynamics as a Force Law

2018 ◽  
Author(s):  
Jürgen Schlitter
Keyword(s):  
Phase Space ◽  
Statistical Mechanics ◽  
Chemical Reactions ◽  
Driving Force ◽  
Second Law Of Thermodynamics ◽  
Second Law ◽  
Constant Energy ◽  
Wide Range

The second law of thermodynamics states the increase of entropy, ΔS > 0, for real processes from state A to state B at constant energy from chemistry over biological life and engines to cosmic events. The connection of entropy to information, phase-space and heat is helpful, but does not immediately convince observers of the validity and basis of the second law. This gave grounds for finding a rigorous, but more easily acceptable reformulation. Here we show using statistical mechanics that this principle is equivalent to a force law ⟨⟨f⟩⟩> 0 in systems where mass centres and forces can be identified. The sign of this net force - the average mean force along a path from A to B - determines the direction of the process. The force law applies to a wide range of processes from machines to chemical reactions. The explanation of irreversibility by a driving force appears more plausible than the traditional formulation as it emphasizes the cause instead of the effect of motions.

Topological analysis of energy hypersurface

1980 ◽  
Vol 45 (9) ◽  
pp. 2463-2473 ◽  
Author(s):  
Jiří Pancíř
Keyword(s):  
Total Energy ◽  
Chemical Reactions ◽  
Reaction Mechanisms ◽  
Driving Force ◽  
Topological Analysis ◽  
Matrix Elements ◽  
Qualitative Information ◽  
Linear Change ◽  
Hartree Fock ◽  
Energy Hypersurface

Topological approximations discussed in the preceeding paper are used for construction of topological energy hypersurfaces of chemical reactions on two levels of a sophistication. A method of a linear change of off diagonal matrix elements reproduces adequately Woodward-Hoffmann rules but it provides only qualitative information about energetical relations. A physically more rigorous hypothesis where the reaction driving force is a function of hybridization changes at reaction sites provides energy hypersurfaces which are correct from a quantitative viewpoint. The method suggested treats the total energy as a function of abstract reaction angles which reflect topological changes accompanying the reaction course. A reaction mechanisms analysis leads then to the analysis of topological energy hypersurfaces which can be treated similarly to that of conventional geometrical hypersurfaces. Formulas for atomic integrals necessary in the construction of Hartree-Fock and CI matrices are derived in the basis of reaction angles mentioned and approximations leading to the semiempirical type of a calculation are discussed.

scholarly journals A new type of power energy for accelerating chemical reactions: the nature of a microwave-driving force for accelerating chemical reactions

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Jicheng Zhou ◽  
Wentao Xu ◽  
Zhimin You ◽  
Zhe Wang ◽  
Yushang Luo ◽  
...  
Keyword(s):  
Chemical Reactions ◽  
Driving Force ◽  
New Type

Galvanic cells and the driving force of chemical reactions

1966 ◽  
pp. 397-436
Author(s):  
FRANK BRESCIA ◽  
JOHN ARENTS ◽  
HERBERT MEISLICH ◽  
AMOS TURK
Keyword(s):  
Chemical Reactions ◽  
Driving Force ◽  
Galvanic Cells

Observations on a spatial-resonance phenomenon

1972 ◽  
Vol 53 (2) ◽  
pp. 209-216 ◽  
Author(s):  
Ian Huntley
Keyword(s):  
Water Wave ◽  
Driving Force ◽  
Low Frequency ◽  
Resonance Phenomenon ◽  
General Mechanism ◽  
Driving Frequency ◽  
Model Situation ◽  
Dissipative Effects ◽  
Low Frequency Oscillations ◽  
Spatial Resonance

The phenomenon was observed during experiments in which a beaker containing water was vibrated in one of its bell modes (the inextensional flexural vibrations of the wall). For certain combinations of driving force and frequency, a standing water wave of large amplitude was generated whose peripheral wavenumber might be either zero (i.e. the wave was radially symmetric) or twice that of the bell mode. This relationship between the wavenumbers of the bell mode and water wave, and the fact that the driving frequency was many times that of the water wave, indicated that this was an instance of a general mechanism that has been studied theoretically by Mahony & Smith (1972). For a model situation, allowing for dissipative effects and nonlinear coupling between nearly resonant oscillations at greatly differing frequencies, they derived a relation-ship between the driving force and frequency representing conditions of neutrals tability (i.e. such that the rate of energy transfer from the high frequency to the low frequency oscillations is zero). The aim of the experimental observations reported here was to check this relationship and other predictions of their theory.

Sign in / Sign up

Export Citation Format

Share Document