Thermochemistry of conjugation of simple cyclopropane derivatives

1982 ◽  
Vol 60 (14) ◽  
pp. 1832-1835 ◽  
Author(s):  
Richard Fuchs ◽  
John H. Hallman ◽  
Michael O. Perlman
Keyword(s):  
Liquid State ◽  
Heats Of Formation ◽  
Isodesmic Reactions ◽  
Gaseous State ◽  
Heats Of Vaporization ◽  
Cyclopropane Derivatives

Heats of vaporization of cyclopropyl cyanide and cyclopropylbenzene have been measured by vaporization calorimetry, and combined with liquid state heats of formation to give gaseous state heats of formation. When these compounds, cyclopropane, 1,1-dimethylcyclopropane, and cyclopropylamine are involved in (hypothetical) isodesmic reactions with ethane to give the isopropyl derivative and propane, the enthalpies of reaction are −116.0 ± 1.3 kJ mol−1, except for cyclopropylbenzene (−103.7 kJ mol−1). The latter is less exothermic, in part, because of slight steric destabilization of the product, isopropylbenzene, but mainly due to 8 kJ mol−1 stabilization of cyclopropylbenzene, which is the only of these cyclopropyl derivatives showing appreciable thermochemical stabilization.

Heats of vaporization of some monosubstituted cyclopropane, cyclobutane, and cyclopentane derivatives. Some observations on the enthalpies of isodesmic ring opening reactions of cyclobutane derivatives

1983 ◽  
Vol 61 (3) ◽  
pp. 503-505 ◽  
Author(s):  
Richard Fuchs ◽  
John H. Hallman
Keyword(s):  
Liquid State ◽  
Ring Opening ◽  
Methyl Ketone ◽  
Heats Of Formation ◽  
Isodesmic Reactions ◽  
Gaseous State ◽  
Ring Opening Reactions ◽  
Cyclobutane Derivatives ◽  
Heats Of Vaporization

The following heats of vaporization at 25 °C (ΔHv0) have been measured by vaporization calorimetry: cyclopropyl methyl ketone (39.41 ± 0.09 kJ mol−1). methyl cyclopropanecarboxylate (41.27 ± 0.06 kJ mol−1), cyclobutyl cyanide (44.34 ± 0.20 kJ mol−1), methyl cyclobutanecarboxylate (44.72 ± 0.09 kJ mol−1), ethylcyclobutane (31.24 ± 0.03 kJ mol−1), and cyclopentyl cyanide (48.12 ± 0.09 kJ mol−1). Values of ΔHv0 of the last four compounds have been combined with liquid state heats of formation to give new values of the gaseous state heats of formation (ΔHf(g)).When cyclobutyl cyanide, ethylcyclobutane, and cyclobutylamine are involved in hypothetical isodesmic reactions with ethane to give propane and isopropyl derivatives, the enthalpies of reaction are −102.1 ± 1.7 kJ mol−1 (−24.4 ± 0.4 kcal/mol), 8.3 kJ mol−1 (2.0 kcal/mol) less exothermic than the value for cyclobutane. Possible origins of this difference are discussed.

A Theoretical Study of Substituted Stepwise Fluorinated Cyclopropanone Keto-Enol System

2003 ◽  
Vol 58 (12) ◽  
pp. 749-755
Author(s):  
Abdullah El-Alali ◽  
Ali A. Marashdeh ◽  
Salim M. Khalil
Keyword(s):  
Theoretical Study ◽  
Dipole Moments ◽  
Heats Of Formation ◽  
Geometrical Parameters ◽  
Free Energies ◽  
Isodesmic Reactions ◽  
Orbital Energies ◽  
Substantial Concentration ◽  
Homo Lumo ◽  
Complete Optimization

MINDO-Forces calculations have been performed with complete optimization of the geometries on stepwise fluorinated cyclopropanones and their enols. Increase in the number of fluorine atoms causes destabilization of cyclopropanone. Perfluorinated enol was found to be present in substantial concentration, as was mentioned in previous work. This is supported by calculations of Gibbs free energies and isodesmic reactions. Geometrical parameters, heats of formation, electron densities, dipole moments and orbital energies (HOMO-LUMO) are reported.

MINDO-Forces Study on Substituted Nitromethane ⇋ aci-Nitromethane Tautomerism

2005 ◽  
Vol 60 (1-2) ◽  
pp. 47-53
Author(s):  
Bareehan M. Salim ◽  
Salim M. Khalil
Keyword(s):  
Theoretical Calculations ◽  
Geometry Optimization ◽  
Heats Of Formation ◽  
Geometrical Parameters ◽  
Free Energies ◽  
Electron Densities ◽  
Isodesmic Reactions ◽  
Complete Geometry Optimization

MINDO-Forces calculations with complete geometry optimization have been performed on nitromethane, aci-nitromethane and X-substituted nitromethane and aci-nitromethane (X = F, OH, NH2, CH3, CN, CF3, NO2, CHO). It is found that nitromethane is more stable than aci-nitromethane by 9.337 kcal/mol. This agrees with theoretical calculations. Thermodynamically, substituted aci-nitro tautomers are more stable than the corresponding nitromethane, except in case of the substituent F. Geometrical parameters, heats of formation, electron densities, Gibbs free energies and isodesmic reactions are reported.

Ring Conserved Isodesmic Reactions:  A New Method for Estimating the Heats of Formation of Aromatics and PAHs

2005 ◽  
Vol 109 (8) ◽  
pp. 1621-1628 ◽  
Author(s):  
R. Sivaramakrishnan ◽  
Robert S. Tranter ◽  
K. Brezinsky
Keyword(s):  
New Method ◽  
Heats Of Formation ◽  
Isodesmic Reactions

scholarly journals Cloud Particles Differential Evolution Algorithm: A Novel Optimization Method for Global Numerical Optimization

2015 ◽  
Vol 2015 ◽  
pp. 1-36 ◽  
Author(s):  
Wei Li ◽  
Lei Wang ◽  
Quanzhu Yao ◽  
Qiaoyong Jiang ◽  
Lei Yu ◽  
...  
Keyword(s):  
Solid State ◽  
Differential Evolution ◽  
Liquid State ◽  
Differential Evolution Algorithm ◽  
Optimization Method ◽  
Benchmark Problems ◽  
Gaseous State ◽  
Mutation Strategy ◽  
Evolution Algorithm ◽  
Cloud Particles

We propose a new optimization algorithm inspired by the formation and change of the cloud in nature, referred to as Cloud Particles Differential Evolution (CPDE) algorithm. The cloud is assumed to have three states in the proposed algorithm. Gaseous state represents the global exploration. Liquid state represents the intermediate process from the global exploration to the local exploitation. Solid state represents the local exploitation. The best solution found so far acts as a nucleus. In gaseous state, the nucleus leads the population to explore by condensation operation. In liquid state, cloud particles carry out macrolocal exploitation by liquefaction operation. A new mutation strategy called cloud differential mutation is introduced in order to solve a problem that the misleading effect of a nucleus may cause the premature convergence. In solid state, cloud particles carry out microlocal exploitation by solidification operation. The effectiveness of the algorithm is validated upon different benchmark problems. The results have been compared with eight well-known optimization algorithms. The statistical analysis on performance evaluation of the different algorithms on 10 benchmark functions and CEC2013 problems indicates that CPDE attains good performance.

scholarly journals The Balance of Multi-phase Gathering and Transport Systems

2019 ◽  
Vol 290 ◽  
pp. 10002
Author(s):  
Cristian Nicolae Eparu ◽  
Sorin Neacsu ◽  
Renata Radulescu ◽  
Alina Petronela Prundurel
Keyword(s):  
Liquid State ◽  
Transport Systems ◽  
Gas Composition ◽  
Transport Parameters ◽  
Gaseous State ◽  
Natural Gases ◽  
Multi Phase

Natural gases are a mixture of hydrocarbons which are generally in a gaseous state. Due to the variation in transport parameters (pressure, temperature) and gas composition, there may be sectors where those appear in liquid state, the condensate. The paper presents a system for managing the quantities of fluids from a network in which the liquid state appears. Based on a simulator that includes flash computation, a physical balance of the transport or gathering network can be made.

Computational Determination of Heats of Formation of Energetic Compounds

1995 ◽  
Vol 418 ◽  
Author(s):  
Peter Politzer ◽  
Jane S. Murray ◽  
M. Edward Grice
Keyword(s):  
Gas Phase ◽  
Density Functional ◽  
Functional Group ◽  
Solid Phase ◽  
Heats Of Formation ◽  
Energetic Compounds ◽  
Phase Data ◽  
Heats Of Vaporization ◽  
Group Effects

AbstractA recently-developed density functional procedure for computing gas phase heats of formation is briefly described and results for several categories of energetic compounds are summarized and discussed. Liquid and solid phase values can be obtained by combining the gas phase data with heats of vaporization and sublimation estimated by means of other relationships. Some observed functional group effects upon heats of formation are noted.

Heats of vaporization and gaseous heats of formation of some five- and six-membered ring alkenes

1979 ◽  
Vol 57 (17) ◽  
pp. 2302-2304 ◽  
Author(s):  
Richard Fuchs ◽  
L. Alan Peacock
Keyword(s):  
Gas Chromatography ◽  
Double Bond ◽  
Heat Capacities ◽  
Membered Ring ◽  
Heats Of Formation ◽  
Group Additivity ◽  
Liquid Heat ◽  
Heats Of Vaporization

The heats of vaporization of 1-methylcyclopentene, 3-methylcyclopentene, ethylidenecyclopentane, 1-ethylcyclopentene, methylenecyclohexane, allylcyclopentane, vinylcyclohexane, ethylidenecyclohexane, allylcyclohexane, 3,3-diethylpentane, 2,2,4,4-tetramethylpentane, and trans-2,2,5,5-tetramethyl-3-hexene have been measured by the gas chromatography – calorimetry method. These values have been combined with previously reported liquid heats of formation to give gaseous values of ΔHf. The results indicate that the internal double bond is favored by about 0.5 kcal over the exo in both 5- and 6-membered rings, but the endo–exo differences are much smaller than previously believed. Several of the liquid heat capacities that were measured were not well predicted by group additivity schemes.

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