Concerning the Problem of the Isokinetic Relationship. III. The Temperature-Dependance of the hammett Equation

1985 ◽  
Vol 38 (5) ◽  
pp. 677 ◽  
Author(s):  
W Linert ◽  
R Schmid ◽  
AB Kudrjawtsev
Keyword(s):  
Benzoic Acid ◽  
Hammett Equation ◽  
Reaction Series ◽  
Temperature Dependent ◽  
Isokinetic Relationship ◽  
A Value ◽  
The Common ◽  
Point Of Intersection ◽  
Temperature Dependance ◽  
The Relationship

It is shown that the temperature-dependence of the Hammett equation is, in contrast to tradition, both physically and experimentally better described by means of temperature-dependent σ and temperature- independent ρ (termed ρo). The relationship between ρo and the customary (temperature dependent) ρ is ρT = ρo(1/T-1/Tbiso)/(1/T-1/Tbiso) where Tbiso , is the isoequilibrium temperature of the benzoic acid ionization, for which the present analysis suggests a value of -255 K, and T is 298 K. In these terms, the temperature variation of the Hammett equation can be evaluated by supplying merely E(u)a (the activation energy for the reaction of the unsubstituted reactant) and ρo, in that the σ value for the isokinetic substituent , i.e., the abscissa of the common point of intersection in the Hammett plot, is σiso = (1/T-1/Tbiso)E(u)a/(2.303Rρo) = E(u)a/(2630po) Further, ρo I related to energies ρo = E(u)a/(ΔH°u-ΔH°s(iso))where ΔH°u and ΔH°s(iso) are the ionization enthalpies of the parent benzoic acid and that bearing the isokinetic substituent , respectively. Analogous equations apply to thermodynamic reaction series when substituting E(u)a for ΔH°u(series). Along these lines the interpretation of the customary Hammett plot is advanced.

Concerning the Problem of the Isokinetic Relationship. IV. The Evaluation of the Isosubstituent Hammett Parameter by Means of Isokinetic and Isoequilibrium Temperatures

1986 ◽  
Vol 39 (2) ◽  
pp. 199 ◽  
Author(s):  
W Linert
Keyword(s):  
Temperature Dependence ◽  
Activation Parameters ◽  
Common Point ◽  
Isokinetic Temperature ◽  
Benzoic Acids ◽  
Reaction Series ◽  
Isokinetic Relationship ◽  
The Common ◽  
Point Of Intersection ◽  
Hammett Parameter

The interrelation between the isosubstituent and the isokinetic relationship is developed and tested for several Hammett reaction series. Two methods of approach to relate the temperature dependence of Arrhenius and Hammett plots are given, one utilizing the isoequilibrium temperature of the ionization of benzoic acids and the other the isokinetic temperature of the respective Hammett reaction series. The efficiency of the approaches for the evaluation of the coordinates of the common point of intersection in the Hammett plot, i.e. the characteristics of the isosubstituent relationship, are compared with each other and with experimental results. With the former approach, by using the activation parameters of only one (commonly the unsubstituted ) member of the series, the temperature dependence of a Hammett line can be predicted provided that the isokinetic temperature of the Hammett series does not approach the experimental temperature range. Otherwise the latter approach must be used which, however, needs the temperature dependence of at least two (or better more) members of the reaction series.

Field and Resonance Components of Substituent Effects in Relation to the Hammett Equation

1972 ◽  
Vol 50 (7) ◽  
pp. 1030-1035 ◽  
Author(s):  
L. D. Hansen ◽  
L. G. Hepler
Keyword(s):  
Substituent Effects ◽  
Similar Reaction ◽  
Hammett Equation ◽  
Reaction Series ◽  
Field Interaction ◽  
Isokinetic Relationship ◽  
Resonance Effects ◽  
Transmission Coefficients ◽  
Substituent Constants ◽  
Specific Reactions

Following Swain and Lupton's analysis of substituent effects, we have taken ΔG0 = aete + artr for a typical substituent effect reaction. In this equation ae and ar are substituent constants for electrostatic field and resonance effects while te and tr are corresponding transmission coefficients. Both substituent constants and tr are taken to be independent of solvent and temperature, while te is taken to depend on both solvent and temperature. General conclusions based on analysis of this model are the following. (i) A Hammett ρσ equation with constant σ values that are valid over a range of temperatures for a variety of reactions in several solvents can be obtained only when either the field or the resonance interaction is negligible compared with the other. (ii) A Hammett ρσ equation can be expected to hold for "similar" reaction series in a given solvent at one temperature even when both the field and resonance interactions are important, (iii) An isoequilibrium or isokinetic relationship can be expected only when the field interaction is dominant.The general equations leading to these and other conclusions are presented so that one can later insert appropriate mathematical descriptions of detailed models and thereby obtain information about specific reactions.

Concerning the problem of the isokinetic relationship. II. The physical significance of the degrees of freedom in the statistical-mechanical model

1984 ◽  
Vol 37 (6) ◽  
pp. 1139 ◽  
Author(s):  
W Linert ◽  
AB Kudrjawtsev
Keyword(s):  
Degrees Of Freedom ◽  
Potential Barrier Height ◽  
Physical Significance ◽  
Reaction Series ◽  
Isokinetic Relationship ◽  
Fitting Procedure ◽  
Statistical Mechanical Model ◽  
Complete Form ◽  
Statistical Mechanical ◽  
The Relationship

The statistical model presented recently for the isokinetic relationship is developed. The physical meaning of the degrees of freedom (s) is explained in terms of ∆Cp‡, i.e. the change in the specific heat between ground and activated states: ∆Cp‡ =-(s-1)R In the case where (s-1)/(E/kBT) cannot be neglected the relationship is ∆Cp‡=-(s-1)(1-kBT/E)R where E denotes the potential barrier height. The results from a digital fitting procedure for the complete form of the model are compared with those obtained from the simplified equations for 'energy-barrier-controlled' reaction series.

Concerning the problem of the isokinetic relationship. I. A statistical mechanical model

1983 ◽  
Vol 36 (10) ◽  
pp. 1903 ◽  
Author(s):  
W Linert ◽  
AB Kudrjawtsev ◽  
R Schmid
Keyword(s):  
Frequency Factor ◽  
Isokinetic Temperature ◽  
Reaction Series ◽  
Empirical Coefficient ◽  
Isokinetic Relationship ◽  
Exponential Factor ◽  
Statistical Mechanical Model ◽  
Statistical Mechanical ◽  
The Common

The equation for the rate constant derived from the statistical theory of kinetics is compared with the common Arrhenius equation. Thereby the pre-exponential factor and the activation energy can be expressed by means of the theoretical quantities, frequency factor (Z0), oscillator number (s), and potential barrier height (E). In these terms the isokinetic relationship can be represented by the equation (c- c) = b(E-E) where c is s- 1 and the bars denote the means in the reaction series under consideration. The empirical coefficient b, in connection with the numerical value of the isokinetic temperature, is proposed to be used as a criterion for the classification of reaction series. The model is exemplified by means of an organic SN2 reaction.

Thermodynamic Analysis of the Hammett Equation, the Temperature Dependence of ρ, and the Isoequilibrium (Isokinetic) Relationship

1971 ◽  
Vol 49 (17) ◽  
pp. 2803-2807 ◽  
Author(s):  
Loren G. Hepler
Keyword(s):  
Differential Equations ◽  
Temperature Dependence ◽  
Thermodynamic Analysis ◽  
Activation Parameters ◽  
Isokinetic Temperature ◽  
Hammett Equation ◽  
Isokinetic Relationship ◽  
Solvent Interactions ◽  
Independent Constant ◽  
The Relationship

Exact thermodynamic analysis of the Hammett equation has led to four differential equations relating δΔH0, δΔS0, δΔCp0, dρ/dT, and d2ρ/dT2. Similar equations can be obtained in terms of activation parameters ΔH≠, etc. For temperature independent δΔH0 and δΔS0 and therefore δΔCp0 = 0, two of these differential equations lead to ρ = ρ∞ [1–(β1/T)] and the familiar isoequilibrium (isokinetic) equation δΔH0 = β1δΔS0. The "isoequilibrium (isokinetic) temperature" represented here by β1 is a temperature independent constant of integration. For constant non-zero δΔCp0 we similarly obtain more complicated expressions for ρ and the "isoequilibrium (isokinetic) temperature." These findings are considered in relation to a model in which environmental contributions (due to solute–solvent interactions) to δΔH0 and δΔS0 are related by a parameter βc. The relationship between β1, and βc is established, and it is shown that in general β1 ≠ βc.

Conceptualising animal exploitation in capitalism: Getting terminology straight

2019 ◽  
Vol 44 (3) ◽  
pp. 401-421
Author(s):  
Christian Stache
Keyword(s):  
Private Property ◽  
Human Case ◽  
Value Theory ◽  
Surplus Value ◽  
Historical Materialist ◽  
A Value ◽  
The Common ◽  
The Relationship ◽  
Mode Of Production ◽  
Means Of Production

In the last three decades, the interchange between Marxism and critical human–animalism has gratifyingly picked up. Scholars use Marxist categories to analyse and criticise the exploitation and oppression of animals in capitalism. But the application of Marx’s original concepts often rests on fragile analogies and judgements. To conceptualise the exploitation of animals accurately and substantiate the common class struggle for humans and animals theoretically, the present article serves to get the terminology straight with respect to four interrelated topics. First, the common charge against Marx’s theory to build on a human–animal dualism is refuted by showing that he understands the relationship between humans and animals as a historical materialist, socio-practical and dialectical differentiation. Second, based on a relational understanding of the capitalist mode of production, I argue that animals are not wage labourers, slaves or super-exploited commodities. Rather, as nature in general, they are super-exploited and despotically oppressed by the capitalist class. This capital–animal relation turns animals into private property and means of production at the hands of capital. It also has significant consequences for a value theory of animal labour. Animals, third, do not create value or surplus value and they do not produce commodities. They produce products and these as well as their labour are appropriated by capital for free. Finally, fourth, I defend the transfer of the concept of alienation to animals in general. But animal alienation has to be derived from the form of social labour as in the human case and it has to include the estrangement from body and life as well due to the special form of animal exploitation in capitalism.

PERSOALAN KEHIDUPAN KONTEMPORER: MENGGAGAS KAJIAN SACHEDINA TENTANG THEOLOGI PLURALISME

EMPIRISMA ◽  
2017 ◽  
Vol 26 (1) ◽  
Author(s):  
Limas Dodi
Keyword(s):  
Religious Pluralism ◽  
Main Argument ◽  
Religious Groups ◽  
Common View ◽  
The Public ◽  
The People ◽  
Muslim Majority ◽  
The Common ◽  
The Relationship ◽  
Religious Differences

According to Abdulaziz Sachedina, the main argument of religious pluralism in the Qur’an based on the relationship between private belief (personal) and public projection of Islam in society. By regarding to private faith, the Qur’an being noninterventionist (for example, all forms of human authority should not be disturb the inner beliefs of individuals). While the public projection of faith, the Qur’an attitude based on the principle of coexistence. There is the willingness of the dominant race provide the freedom for people of other faiths with their own rules. Rules could shape how to run their affairs and to live side by side with the Muslims. Thus, based on the principle that the people of Indonesia are Muslim majority, it should be a mirror of a societie’s recognizion, respects and execution of religious pluralism. Abdul Aziz Sachedina called for Muslims to rediscover the moral concerns of public Islam in peace. The call for peace seemed to indicate that the existence of increasingly weakened in the religious sense of the Muslims and hence need to be reaffi rmed. Sachedina also like to emphasize that the position of peace in Islam is parallel with a variety of other doctrines, such as: prayer, fasting, pilgrimage and so on. Sachedina also tried to show the argument that the common view among religious groups is only one religion and traditions of other false and worthless. “Antipluralist” argument comes amid the reality of human religious differences. Keywords: Theology, Pluralism, Abdulaziz Sachedina

Migraine: Genetic Variants and Clinical Phenotypes

2019 ◽  
Vol 26 (34) ◽  
pp. 6207-6221 ◽  
Author(s):  
Innocenzo Rainero ◽  
Alessandro Vacca ◽  
Flora Govone ◽  
Annalisa Gai ◽  
Lorenzo Pinessi ◽  
...  
Keyword(s):  
Genetic Variants ◽  
Association Studies ◽  
Mthfr Gene ◽  
Genome Wide Association Studies ◽  
Clinical Phenotypes ◽  
Network Analyses ◽  
Genome Wide ◽  
Genomic Studies ◽  
The Common ◽  
The Relationship

Migraine is a common, chronic neurovascular disorder caused by a complex interaction between genetic and environmental risk factors. In the last two decades, molecular genetics of migraine have been intensively investigated. In a few cases, migraine is transmitted as a monogenic disorder, and the disease phenotype cosegregates with mutations in different genes like CACNA1A, ATP1A2, SCN1A, KCNK18, and NOTCH3. In the common forms of migraine, candidate genes as well as genome-wide association studies have shown that a large number of genetic variants may increase the risk of developing migraine. At present, few studies investigated the genotype-phenotype correlation in patients with migraine. The purpose of this review was to discuss recent studies investigating the relationship between different genetic variants and the clinical characteristics of migraine. Analysis of genotype-phenotype correlations in migraineurs is complicated by several confounding factors and, to date, only polymorphisms of the MTHFR gene have been shown to have an effect on migraine phenotype. Additional genomic studies and network analyses are needed to clarify the complex pathways underlying migraine and its clinical phenotypes.

Relation Between Metacognitive Ability with Science Process Skills on Grade 8th Students in MTs Negeri 3 Parigi

2020 ◽  
Vol 3 (1) ◽  
pp. 8-13
Author(s):  
Moch. Munir ◽  
Amiruddin Kade ◽  
Muslimin Muslimin
Keyword(s):  
Research Result ◽  
Reverse Direction ◽  
Process Skills ◽  
Science Process Skills ◽  
A Value ◽  
Regression Test ◽  
Feasibility Test ◽  
Relationship Of ◽  
The Relationship ◽  
Academic Year

This study aims to determine the relations between metacognitive to science process skills on grade VIII students MTs Negeri 3 Parigi. This research is descriptive, the approach used is a quantitative approach, manifested in the form of numbers analyzed by statistics and the results are described. The population is students of MTs Negeri 3 Parigi Academic Year 2017-2018 with a population of three classes, with a sample of 30 students. The instrument used is a metacognitive questionnaire consisting of 50 questions and an essay about science process skills 6 questions test. The result of the prerequisite test of the research result is all metacognitive indicators of normal and linear distributed and based on the regression feasibility test show that all data is feasible for regression test. The result of the regression test and test of determination to obtain a value which is not significant. Based on the results of the research analysis it can be concluded that the relationship of each metacognitive indicator to science process skills was not significant even there were metacognitive indicators that reverse direction significantly. The magnitude of the relationship of each metacognitive indicator with science process skills maximum 15.3%.  

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