Chemistry of Transition Metals. V. Further Studies on the Mechanism of Reaction of n-Alkyl Chlorides with Metals of the First Transition Period

1975 ◽  
Vol 53 (17) ◽  
pp. 2619-2623 ◽  
Author(s):  
Robert W. Egan ◽  
John F. Harrod
Keyword(s):  
Transition Metals ◽  
Pressure Range ◽  
Reaction Rate ◽  
Transition Period ◽  
Halogen Bond ◽  
Dissociative Adsorption ◽  
Rate Law ◽  
Order Rate ◽  
Mechanism Of Reaction ◽  
Rate Of Reaction

The rate of reaction of n-propyl chloride on polycrystalline evaporated titanium films has been shown to follow a strictly half-order rate law in the pressure range 0.1–0.01 Torr at 220 °C. The reaction rate was not influenced by the product propene. Experiments using a mixture of 1-bromopropane and l-chloropropane-1-d1 gave no indication of halogen interchange on either titanium or chromium, thus excluding rapid, reversible dissociative adsorption of the carbon–halogen bond as an explanation of the half-order rate law.

THE KINETICS OF THE DECOMPOSITION REACTIONS OF THE LOWER PARAFFINS: II. ISOBUTANE

1938 ◽  
Vol 16b (8) ◽  
pp. 260-272 ◽  
Author(s):  
E. W. R. Steacie ◽  
I. E. Puddington
Keyword(s):  
Rate Constants ◽  
Pressure Range ◽  
Reaction Rate ◽  
High Pressures ◽  
Initial Pressure ◽  
First Order ◽  
Decomposition Reactions ◽  
Order Rate ◽  
Reaction Proceeds ◽  
Kinetics Of

The kinetics of the thermal decomposition of isobutane has been investigated over an initial pressure range of from 5 to 60 cm., and at temperatures from 522 to 582 °C. The initial first order rate constants at high pressures are given by[Formula: see text]The results are in general agreement with those obtained by previous investigators. The reaction rate falls off with diminishing pressure, and the first order rate constants in a given run diminish strongly as the reaction proceeds. This behavior is similar to that of n-butane.Analyses of the products of the reaction were made at various stages, temperatures, and initial pressures by low-temperature distillation in a still of the Podbielniak type. The initial products were found by extrapolation to be H2, 35; CH4, 14; C2H4, 0.9; C2H6, 0.9; C3H6, 14; and C4H8, 35%. The results are compared with those of other workers.

scholarly journals PENGEMBANGAN BAHAN AJAR KIMIA RINTISAN SMA BERTARAF INTERNASIONAL KELAS XI MATERI LAJU REAKSI

2012 ◽  
Vol 13 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Inova Putri Carera ◽  
I Wayan Dasna
Keyword(s):  
High School ◽  
High School Students ◽  
Reaction Mechanism ◽  
Reaction Rate ◽  
Reaction Order ◽  
Average Score ◽  
School Students ◽  
Factors Affecting ◽  
Rate Law

This study was aimed to develop teaching materials about chemical reaction rate which covered materials adapted to A-Level High School students of grade XI in Pioneer International Standard High School (RSMA-BI). The developmental research was adopting the instructional development model 4D which include four stages of development, namely define, design, develop, and disseminate. Instructional materials were written in English consist of seven topics titled: Reaction Rate Concept, The Exchange's Expressions, Rate Law and Reaction Order, Experimental Determination of a Rate Law, Reaction Mechanism, Theories of Reaction Rate, Factors Affecting Reaction Rate. Results of content validation from content experts obtained the average score of 3. 56 of 14 range of scores which means valid / good / decent. Test limited to high school students of RSBI obtained an average score of 3.35 (valid / good / decent). The results of the use of teaching materials obtained a score of 77.8 which is above the minimal passing grade (75). Therefore it can be concluded that the materials were feasible to be used in the classroom.Penelitian ini bertujuan untuk mengembangkan bahan ajar laju reaksi dengan cakupan materi yang disesuaikan dengan A-Level untuk siswa kelas XI Rintisan Sekolah Menengah Atas Bertaraf Internasional (RSMA-BI. Rancangan penelitian pengembangan mengadaptasi model pengembangan bahan ajar Model 4D yang meliputi empat tahap pengembangan, yaitu define, design, develop dan disseminate. Produk pengembangan adalah bahan ajar kimia RSMA-BI kelas XI materi laju reaksi yang ditulis dalam bahasa Inggris menggunakan pendekatan kontekstual. Bahan ajar terdiri atas empat bagian utama yaitu pendahuluan, materi, evaluasi dan penutup. Materi tersusun atas tujuh sub materi yaitu Reaction Rate Concept, The Rates Expressions, Rate Law and Reaction Order, Experimental Determination of a Rate Law, Reaction Mechanism, Theories of Reaction Rate, Factors Affecting Reaction Rate. Hasil validasi isi dari ahli materi diperoleh nilai rata-rata 3,56 dari rentang skor 1-4 dengan kriteria valid/baik/layak. Hasil uji terbatas pada siswa SMA RSBI diperoleh nilai rata-rata 3,35 dari rentang skor 1-4 dengan kriteria valid/baik/layak. Hasil uji penggunaan bahan ajar diperoleh skor sebesar 77,8. Skor ini diatas SKM (Skor Kelulusan Minimal) yaitu 75 sehingga dapat disimpulkan bahwa bahan ajar telah layak dan dapat digunakan dalam pembelajaran di kelas.

scholarly journals PERIODATE OXIDATION OF PEG–600, AN ESSENTIAL PHARMACEUTICAL POLYMER

2019 ◽  
pp. 251-256
Author(s):  
K. V. S. KOTESWARA RAO ◽  
R. VENKATA NADH ◽  
K. VENKATA RATNAM
Keyword(s):  
Polyethylene Glycol ◽  
Oxygen Atom ◽  
Temperature Dependence ◽  
Reaction Rate ◽  
Periodate Oxidation ◽  
Alkali Concentration ◽  
Rate Of Reaction ◽  
Atom Loss ◽  
Kinetics Of ◽  
Peg 600

Objective: To study the kinetics of periodate oxidation of polyethylene glycol-600 (PEG-600), a familiar non-toxic polymer used in pharmaceutical and other fields of industry. Methods: Reactions were carried out in alkaline medium and measured the kinetics by iodometry. One oxygen atom loss or two electrons transfer was observed per each molecule of periodate i.e., the rate of reaction was measured periodate converts to iodate because the formed iodate species is unable to oxidize the substrate molecules. Results: Based on log (a-x) versus t plots, order w. r. t. oxidant (periodate) is unity. Reactions were found to be independent of substrate (PEG-600) concentration. A decrease in rate with an increase in alkali concentration [OH–] was found and order was inverse fractional. Temperature dependence of reaction rate was studied and then calculated the corresponding Arrhenius parameters. Conclusion: An appropriate rate law was proposed by considering the above experimental results.

Triphase Catalysis Using Silica Gel as Support

2013 ◽  
Vol 11 (1) ◽  
pp. 347-352
Author(s):  
T. Sankarshana ◽  
J. Soujanya ◽  
A. Anil Kumar
Keyword(s):  
Potassium Permanganate ◽  
Silica Gel ◽  
Reaction Rate ◽  
Phase Transfer ◽  
Supported Catalysts ◽  
Batch Reactor ◽  
Kinetic Regime ◽  
Rate Of Reaction ◽  
Potential Applications ◽  
Triphase Catalysis

Abstract The oxidation reaction of 2-ethyl-1-hexanol with potassium permanganate in the presence and absence of silica-gel-supported phase-transfer catalyst (PTC) in triphasic conditions was studied. In a batch reactor, the performance of the solid-supported catalysts was compared with unsupported catalyst and without the catalyst. The effect of speed of agitation, catalyst concentration, potassium permanganate concentration and temperature on reaction rate was studied. The reaction is found to be in the kinetic regime. The rate of reaction with the catalyst immobilised on the silica gel was less compared to the catalyst without immobilisation. Triphase catalysis with supported PTCs has potential applications in the continuous quest for greener industrial practices.

Hydrogen Recombiner: Theoretical Parametric Study

2002 ◽  
Author(s):  
Gilles Avakian
Keyword(s):  
Hydrogen Concentration ◽  
Total Pressure ◽  
Reaction Rate ◽  
Published Data ◽  
Geometrical Parameters ◽  
Surface Kinetics ◽  
Total Rate ◽  
Diffusion Controlled ◽  
Rate Of Reaction ◽  
Linear Behaviour

There is not yet published data concerning a complete overview of the behaviour of a SIEMENS recombiner versus the thermal hydrualic conditions and the geometry of the catalytic plates. This paper reports on a numerical behaviour of the recombiner depending on several gas parameters as the total pressure, and the hydrogen concentration, as well as geometrical parameters of the catalytic elements as the height and the spacing. We use a theoretical model validated by using the KALI experiments. In this model (Avakian, 1999), the reaction rate is diffusion-controlled, i.e. the contribution of surface kinetics to the total rate of reaction is neglected. We demonstrate a quasi-linear behaviour of the recombination rate vs. the total pressure and the hydrogen concentration. We display the benefit in using smaller catalytic plates instead of taller plates and we give an idea of the influence of the spacing between the catalytic plates.

THE ROLE OF ADSORPTION IN CONTROLLING THE RATE OF REACTION OF CHLORAMBUCIL WITH PROTEIN

1963 ◽  
Vol 41 (4) ◽  
pp. 931-939 ◽  
Author(s):  
J. H. Linford
Keyword(s):  
Molecular Weight ◽  
Carboxylic Acid ◽  
Bovine Serum Albumin ◽  
Inverse Relationship ◽  
Reaction Rate ◽  
The Other ◽  
Alkylation Reaction ◽  
Rate Of Reaction

Two proteins, haemoglobin and bovine serum albumin, have been studied with respect to their rates of alkylation by chlorambucil in vitro at 37 °C and pH 8.4. The proteins are of nearly the same molecular weight and free carboxylic acid content, but the alkylation reaction is 30 times faster with haemoglobin. On the other hand, the adsorption of chlorambucil by albumin is 20 times greater than that exhibited by haemoglobin. This inverse relationship between extent of adsorption and reaction rate suggests that adsorption protects the chlorambucil from activation in the solvent.

scholarly journals Kinetics of the reaction of streptokinase-plasmin complex with purified human and mouse α2-macroglobulin. Implications for mechanism

1989 ◽  
Vol 264 (3) ◽  
pp. 745-752 ◽  
Author(s):  
P K Anonick ◽  
W H Vetter ◽  
S L Gonias
Keyword(s):  
Order Rate Constant ◽  
Direct Reaction ◽  
Major Mechanism ◽  
Order Rate ◽  
Α2 Macroglobulin ◽  
Rate Of Reaction ◽  
Fibrinogenolytic Activity ◽  
Kinetics Of ◽  
Human And Mouse

Streptokinase-human plasmin complex (Sk-hPm) reacted rapidly with purified mouse alpha 2-macroglobulin (m alpha 2M) in vitro at 37 degrees C. Approx. 98% of the plasmin in Sk-hPm bound covalently to at least one m alpha 2M subunit. Most of the streptokinase dissociated (95%). The rate of Sk-hPm inactivation clearly depended on the m alpha 2M concentration. With 1.2 microM-m alpha 2M, 50% of the Sk-hPm (0.02 microM) reacted in less than 50 s. A double-reciprocal plot comparing pseudo-first-order rate constants (kapp.) and m alpha 2M concentration yielded a second-order rate constant of 2.3 x 10(4) M-1.s-1 (r = 0.97). This value is an approximation, since Sk-hPm preparations are heterogeneous. Sk-hPm reacted with human alpha 2M (h alpha 2M), forming alpha 2M-plasmin complex (98% covalent). More than 99% of the streptokinase dissociated. The rate of reaction of Sk-hPm with h alpha 2M did not clearly depend on inhibitor concentration. The kapp. values determined with 0.6-1.2 microM-h alpha 2M were decreased 10-20-fold compared with m alpha 2M. In order to study the effect of Sk-hPm heterogeneity on the reaction with alpha 2M, the proteinase was incubated for various amounts of time at 37 degrees C before addition of inhibitor. The enzyme amidase activity was maximal within 5 min; however, reaction of Sk-hPm with m alpha 2M or h alpha 2M was most extensive after 20 min and 2 h respectively. After incubation for more than 1 h, Sk-hPm acquired fibrinogenolytic activity, suggesting plasmin dissociation. Therefore the enhanced reaction of h alpha 2M with ‘older’ Sk-hPm preparations may have resulted in part from dissociated plasmin or ‘plasmin-like’ species. By contrast, the reaction of Sk-hPm with m alpha 2M was most rapid when the proteinase preparation was free of plasmin, indicating direct reaction of Sk-hPm with m alpha 2M as the only major mechanism. Finally, streptokinase-cat plasminogen complex reacted more extensively with m alpha 2M than with h alpha 2M, suggesting that m alpha 2M may be a superior inhibitor with this class of plasminogen activators in general.

AN EMPIRICAL STUDY ON THE HYDROGEN PEROXIDE REACTION WITH IODIDE IN ACID CONDITION

2015 ◽  
Vol 11 (1) ◽  
pp. 72
Author(s):  
Ayuni Dita Rosalia ◽  
Patiha Patiha ◽  
Eddy Heraldy
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction Order ◽  
Ph Value ◽  
Order Reaction ◽  
Isolation Method ◽  
Acid Condition ◽  
Rate Law ◽  
Mechanism Of Reaction ◽  
Oxygen Gas

<p>This research aimed to find out I<sup>-</sup> reaction order in the mechanism of  hydrogen peroxide reaction with iodide in acid condition, to find out the form of rate law, and to show the role of H<sup>+</sup> in reaction. The experiment for determining reaction order was carried out with isolation method using UV-Vis spectrophotometry. The order reaction was obtained from the <em>r</em> value approaching one, the results of its linear regression. The form of rate law was viewed from the presence or absence of oxygen gas. Meanwhile the role of H<sup>+</sup> in reaction was determined by observing the pH value in 60 minutes.</p><p>The result of experiment shows that the mechanism of reaction has rate law in the form of fraction, in which I<sup>-</sup> could be in zero and first orders. In addition, the rate law in this experimental condition is not an addition in the absence of O<sub>2</sub> and relatively equal <em>k</em><sub>obs</sub> value in the same order. The role of H<sup>+ </sup>is observed not as catalyst, but reactant.</p>

Nachbargruppeneffekte bei der Aminolyse von Estern, II Die Aminolyse von 2-(2-Hydroxybenzyl)phenylacetaten / Neighboring Group Effects in the Aminolysis of Esters, II The Aminolysis of 2-(2-Hydroxybenzyl)phenylacetates

1978 ◽  
Vol 33 (4) ◽  
pp. 439-449 ◽  
Author(s):  
Volker Böhmer ◽  
Klaus Wörsdörfer
Keyword(s):  
Second Order ◽  
Phenyl Acetate ◽  
Third Order ◽  
Neighboring Group ◽  
Rate Law ◽  
Order Rate ◽  
Methyl Phenyl ◽  
Group Effects

Abstract The aminolysis of 2-(2-hydroxybenzyl)phenyl acetates with n-butylamine in dioxane is much faster than for the corresponding 2-(2-methoxybenzyl)phenyl acetates or 2-methyl-phenyl acetates. The kinetic results can be explained by two equivalent mechanisms. Both of them include the formation of a 1:1-complex between 2-(2-hydroxybenzyl)phenyl acetate and n-butylamine which is formed in an equilibrium. The reaction of this complex according to a second order rate law seems to be more probable than the reaction of the free ester according to a third order rate law.

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