Solvolysis of Sulphonyl Halides. II. The Alcoholysis of Aromatic Sulphonyl Chlorides in Ethanol-Acetone and Methanol-Acetone

1961 ◽  
Vol 14 (2) ◽  
pp. 205 ◽  
Author(s):  
FE Jenkins ◽  
AN Hambly
Keyword(s):  
Experimental Temperature ◽  
Isokinetic Temperature ◽  
Reaction Conditions ◽  
Temperature Range ◽  
Experimental Temperature Range

The solvolysis of aromatic sulphonyl chlorides in methanol-acetone and ethanol-acetone shows only small, irregular effects due to para-substituents because the experimental temperature range is close to the isokinetic temperature. The modification of reaction conditions in SN2 substitutions, so that the isokinetic condition is brought into the experimental temperature range, is discussed. Rates for methanolysis are lower than those for hydrolysis and are about four times the rates for the corresponding ethanolysis reactions.

An isokinetic relationship in the oxidation of acetals by ozone. Evidence for rotation before the oxidation of acyclic acetals

1979 ◽  
Vol 57 (23) ◽  
pp. 3041-3046 ◽  
Author(s):  
Roland J. Taillefer ◽  
Shirley E. Thomas ◽  
Yves Nadeau ◽  
Helmut Beierbeck
Keyword(s):  
Conformational Change ◽  
Rate Constants ◽  
Second Order ◽  
Experimental Temperature ◽  
Isokinetic Temperature ◽  
Isokinetic Relationship ◽  
Cyclic Acetals ◽  
Temperature Range ◽  
Order Rate ◽  
Experimental Temperature Range

Second order rate constants for the oxidation by ozone of several acyclic acetals of heptaldehyde were determined at several temperatures. An isokinetic relationship is shown to exist for this series of reactions and the isokinetic temperature was found to be below the experimental temperature range, a domain of temperatures where reactivity is dominated by entropy factors. These results are contrasted with those obtained for cyclic acetals of heptaldehyde, where the isokinetic temperature falls above the working temperatures, a domain of temperatures where reactivity depends mainly on enthalpy factors. These results are interpreted in terms of a conformational change before oxidation in the acyclic acetals.

scholarly journals A Preliminary Experiment of Non-Catalytic Transesterification: Thermal Analysis of Palm Oil and Biodiesel at Different Ratio

2018 ◽  
Vol 7 (4.35) ◽  
pp. 190
Author(s):  
Mei Yin Ong ◽  
Bello Salman ◽  
Nor-Insyirah SAL ◽  
Refal Hussein ◽  
Saifuddin Nomanbhay
Keyword(s):  
Thermal Degradation ◽  
Palm Oil ◽  
High Energy ◽  
Microwave Energy ◽  
Biodiesel Production ◽  
Experimental Temperature ◽  
External Energy ◽  
Temperature Range ◽  
Experimental Temperature Range ◽  
Subcritical Condition

Currently, the biodiesel production technology is moving toward the trend of non-catalytic reaction under subcritical condition as the conventional non-catalytic transesterification requires high energy input and high production cost. Hence, non-catalytic biodiesel production under subcritical condition using microwave energy is proposed. Before that, thermogravimetric analysis (TGA) was conducted to characterize the biodiesel feedstock and determine the suitable experimental temperature range for the proposed method. Besides, the thermal behavior of the palm oil and biodiesel at different stages of reaction was also investigated. The results showed that the palm oil and biodiesel were started to degrade from 335ºC and 160ºC respectively. However, the degradation point of palm oil was higher than the supercritical temperature of DMC. So, external energy is needed to bring down the operating condition, such as microwave energy as it has potential to reduce the activation energy. To further eliminate the problem of biodiesel thermal degradation during the transesterification process, the suggested experimental temperature range is within 80ºC to 180ºC, which is from the temperature lower than the boiling point of DMC (<90ºC) to the temperature slightly higher than the biodiesel thermal degradation point. Furthermore, DSC result indicated that palm oil requires 518.35kJ/mol to decompose.

Gas Pressure Forming of Amorphous Fe78Si9B13 Alloy

2007 ◽  
Vol 551-552 ◽  
pp. 575-580
Author(s):  
Xi Feng Li ◽  
Kai Feng Zhang ◽  
Wen Bo Han ◽  
Guo Feng Wang
Keyword(s):  
Crystallization Temperature ◽  
Deformation Behavior ◽  
Amorphous Ribbon ◽  
Superplastic Forming ◽  
Gas Pressure ◽  
Experimental Temperature ◽  
Dome Height ◽  
Ribbon Thickness ◽  
Temperature Range ◽  
Experimental Temperature Range

The deformation behavior of gas pressure forming of amorphous Fe78Si9B13 alloy was investigated under equibiaxial tension. The gas pressure forming was carried out in the temperature range of 430°C~530°C below the crystallization temperature Tx and die apertures of 5mm~10mm. The dome height and amorphous ribbon thickness of deformed specimens at the pole was measured. It was found that amorphous Fe78Si9B13 alloy had exhibited good plasticity in the experimental temperature range. The near-semisphere specimens of the radius 5mm and the height 4.5mm were obtained from the gas-pressure forming at 450°C and 530°C for 30min, which is similar to the superplastic forming.

A comparison of two empirical pKa(T) equations from 298 to 448 K for 2,9-Dimethyl-1,10-phenanthroline

1978 ◽  
Vol 31 (5) ◽  
pp. 1145 ◽  
Author(s):  
RD Alexander
Keyword(s):  
Experimental Temperature ◽  
Temperature Range ◽  
Experimental Temperature Range

The two most commonly used three-term equation1,2 describing the variation of pKa with temperature are compared over the range 298-448 K for 2,9-dimethyl-1,10-phenanthroline. Both equations represent the data equally well over the experimental temperature range. First-difference calculations and the Σ-plot method are used to fit the data.

Transformation of 1-Butene over Synthetic Zeolites

1992 ◽  
Vol 57 (4) ◽  
pp. 869-881 ◽  
Author(s):  
Italo Ferino ◽  
Roberto Monaci ◽  
Vincenzo Solinas ◽  
Lucio Forni ◽  
Antonio Rivoldini ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Continuous Flow ◽  
Liquid Mixture ◽  
Isomerization Reaction ◽  
Reaction Conditions ◽  
Title Reaction ◽  
Y Zeolites ◽  
Temperature Range ◽  
Flow Microreactor ◽  
Synthetic Zeolites

The behaviour of several zeolites as catalysts for the title reaction has been investigated by means of a continuous flow microreactor. Runs performed at atmospheric pressure indicated that at 423 K the completely protonic forms of the zeolites catalyze just the isomerization reaction. In the case of Y zeolites, oligomerization occurs only over the partially decationated samples, in the temperature range between 373 and 423 K and W/F between 0.2 and 22 gcath/g1-but, to an extent which depends on the reaction conditions. Most of the catalysts were tested also under pressure (4.05 MPa) at 423 K. The protonic forms of Y and ZSM-5 zeolites seem promising catalysts in terms of both conversion and selectivity to oligomers. The 1-olefins account for 30% of the entire olefinic mixture. The octenes, which account for 70% of the liquid mixture, are mostly formed of dimethylhexenes. Trimers are also formed during the reaction and, in the very particular case of H[B]ZSM-5, tetramers are produced.

Induced Fundamental Infrared Band of Nitrogen Dissolved in Solid Argon

1971 ◽  
Vol 49 (24) ◽  
pp. 3201-3207 ◽  
Author(s):  
J. De Remigis ◽  
H. L. Welsh ◽  
R. Bruno ◽  
D. W. Taylor
Keyword(s):  
Path Length ◽  
Harmonic Approximation ◽  
Host Lattice ◽  
Mode Frequency ◽  
Local Mode ◽  
Infrared Band ◽  
Temperature Range ◽  
Solid Argon ◽  
Experimental Temperature Range ◽  
Good Agreement

The induced fundamental infrared band of nitrogen dissolved in solid argon was studied over the temperature range 55–81 K with a path length of 40 cm and molar N2 concentrations of 1−2%. The spectrum consists of combination tones of lattice transitions with the N2 1 ← 0 vibrational transition. Lattice transition frequencies of 70 and 39 cm−1 at 55 K are identified with a local mode and vibrations of the host-lattice atoms respectively. We have computed the local-mode frequency over the experimental temperature range using one-defect theory in a harmonic approximation employing temperature-corrected experimental phonon frequencies and obtain good agreement with the observed values. The 39 cm−1 peak can be identified with features of the transverse region of the Ar phonon density of states.

Metal complexes of 1,10-Phenanthroline derivatives. VII. Complexes of 1,10-Phenanthroline-2-carbaldehyde hydrazones

1974 ◽  
Vol 27 (5) ◽  
pp. 965 ◽  
Author(s):  
HA Goodwin ◽  
DW Mather
Keyword(s):  
Field Strength ◽  
Metal Complexes ◽  
High Spin ◽  
Spin State ◽  
Spin Transition ◽  
Pronounced Change ◽  
Temperature Range ◽  
Spin Pairing ◽  
Bivalent Iron ◽  
Experimental Temperature Range

A series of substituted hydrazones derived from 1,l0-phenanthroline-2-carbaldehyde and their bis-ligand complexes with bivalent iron and nickel are described. The hydrazones show a gradation in field strength and this is reflected in the spin-state of the iron complexes. The methylhydrazone complex is essentially low-spin over the temperature range 83-363 K but the presence of some spin-free species at high temperatures is evident. Within the same range the dimethylhydrazone complex is essentially high-spin but undergoes significant spin-pairing and the phenylhydrazone complex displays a complete 5T2 → 1A1 spin transition. This transition is very sharp, resulting in a pronounced change in the magnetism, and colour, of the complex within a few degrees. Complexes of the 2-pyridylhydrazone, the methylphenylhydrazone and the diphenylhydrazone are high-spin over the entire experimental temperature range.

Standard and reversible anodic potentials of the electrosynthesis of peroxodisulfates at 0–50 °C

2011 ◽  
Vol 76 (4) ◽  
pp. 343-350
Author(s):  
Jan Balej
Keyword(s):  
Activity Coefficients ◽  
Conversion Degree ◽  
Electrochemical Reactions ◽  
Reaction Conditions ◽  
Temperature Range ◽  
Ammonium Peroxodisulfate ◽  
Saturated Solutions

Standard potentials of the couples S2O82–/SO42– and S2O82–/HSO4– in the temperature range 0–50 °C and reversible anodic potentials of the electrosynthesis of peroxodisulfates at various initial concentrations of M2SO4 and H2SO4, various conversion degree of sulfate to peroxodisulfate in the same temperature range under neglecting the effect of activity coefficients of reaction components have been derived. Reversible anodic potentials of the electrosynthesis of almost saturated solutions of ammonium peroxodisulfate in the temperature range 10–40 °C under various reaction conditions have been calculated on taking into account the corresponding activity coefficients. It has been shown that the reversible anodic potentials under respecting activity coefficients of reaction components are by about 20–30 mV higher. The results of this contribution can be applied to all chemical or electrochemical reactions of peroxodisulfates.

The energetics of the oxidative addition of trisubstituted silanes to photochemically generated (η5-C5R5)Mn(CO)2

1996 ◽  
Vol 74 (11) ◽  
pp. 1959-1967 ◽  
Author(s):  
Bentley J. Palmer ◽  
Ross H. Hill
Keyword(s):  
Key Words ◽  
Kinetic Data ◽  
Addition Reaction ◽  
Solvent Molecule ◽  
Oxidative Addition ◽  
Isokinetic Temperature ◽  
Arrhenius Law ◽  
Isokinetic Relationship ◽  
Temperature Range ◽  
Oxidative Addition Reaction

The rates for the oxidative addition reaction of trisubstituted silanes (Et3SiH, Et2MeSiH, EtMe2SiH, Et2SiH2) to photochemically generated (η5-C5R5)Mn(CO)2 (R5 = H5, Me5, H4Me) species have been measured for the temperature range 70–125 K. The reactions were carried out in either neat silane or a 50/50, by volume, mixture of methylcyclohexane and silane. The activation energies, determined using Arrhenius law, varied from 2 to 35 kj/mol. The kinetic data fit an isokinetic relationship with an isokinetic temperature of 102 ± 6 K. The results are interpreted in terms of a variation in the loss of solvation prior to the oxidative addition. When the solvating molecule is methylcyclohexane, then loss of the solvent molecule precedes oxidative addition. In cases where solvation is by the silane, the incomplete loss of this silane precedes the oxidative addition. Key words: mechanism, oxidative addition, solvation.

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