Rate and equilibrium constants have been determined for both the aldol addition and the elimination steps in the intramolecular condensation reactions of 2,5-hexanedione, 2,6-heptanedione, 1-phenyl-1,5-hexanedione, and 5-oxohexanal. The overall thermodynamics are similar for cyclization of 2,5-hexanedione and 2,6-heptanedione; conversion of 2,5-hexanedione to the corresponding enone is actually more favorable, but the cyclization of 2,5-hexanedione is 2400 times slower than that of 2,6-heptanedione. As expected on the basis of intermolecular analogs, the addition step is less favorable and slower for 1-phenyl-1,5-hexanedione, and the addition step for 5-oxohexanal is more favorable though similar in rate to that for heptanedione. Detailed analysis of the kinetics and equilibrium for all of these compounds, as well as 2-(2-oxopropyl)benzaldehyde, in terms of Marcus theory, leads to the same intrinsic barriers for the intramolecular reactions as were seen previously for the intermolecular reactions. This means that rate constants for intramolecular aldol reactions should be predictable from the energetics of the reactions and that the effective molarity can be calculated. Methods for estimating thermodynamic quantities for reactants and products of these reactions have been examined.
Transacetalization equilibrium constants can be measured in methanol solution. This allows a ladder of equilibrium constants to be constructed from acetophenone, for which the equilibrium constant for acetal formation has been measured in methanol, to methyl formate, for which it has not. This is the first direct measurement of an equilibrium constant for formation of an acetal of an acyclic ester. We have also determined equilibrium constants for acetal formation from benzophenone and pinacolone. The value for benzophenone is inconsistent with the value reported for the diethyl acetal by Pfeiffer and Adkins (G.J. Pfeiffer and H. Adkins. J. Am Chem. Soc. 53, 1043 (1931)). We must conclude that their analytical method was subject to systematic errors.
Accurate conditions monitoring and early wrong action warnings of relay protection in the Smart Substation is the basic guarantee to realize the normal operation of primary and secondary system of the power grid. At present, the traditional operation and maintenance monitoring methods of relay protections have poor timeliness, while some automatic monitoring methods have insufficient early warning performance, and lack the online action deduction function independent of the actual device. In this paper, a design method of integrated action deduction system including protection logic reasoning and software and hardware operation condition is proposed. The system can receive real-time operation information of protection online, simulate different types of faults, and output the recording information of sub modules belongs to the action deduction system. It can realize the online monitoring of device faults such as deducing the correctness of setting values at a certain time in the future, giving the wrong action warnings and predicting the probability of them as well, which effectively improves the operation and maintenance efficiency of the secondary system in the intelligent substation.
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