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.

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.

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.

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.

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.

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.

Defects in ion implanted silicon

1978 ◽  
Vol 36 (1) ◽  
pp. 386-387
Author(s):  
J.A. Lambert ◽  
P.S. Dobson
Keyword(s):  
Defect Structure ◽  
Dislocation Loops ◽  
Frank Loop ◽  
Burgers Vector ◽  
Temperature Range ◽  
Perfect Dislocation ◽  
Contrast Analysis ◽  
Image Position ◽  
Ion Implanted

The defect structure of ion-implanted silicon, which has been annealed in the temperature range 800°C-1100°C, consists of extrinsic Frank faulted loops and perfect dislocation loops, together with‘rod like’ defects elongated along <110> directions. Various structures have been suggested for the elongated defects and it was argued that an extrinsically faulted Frank loop could undergo partial shear to yield an intrinsically faulted defect having a Burgers vector of 1/6 <411>.This defect has been observed in boron implanted silicon (1015 B+ cm-2 40KeV) and a detailed contrast analysis has confirmed the proposed structure.

Domain coarsening by grain boundary migration in ordered Ni4Mo

1986 ◽  
Vol 44 ◽  
pp. 560-561
Author(s):  
K. Vasudevan ◽  
H. P. Kao ◽  
C. R. Brooks ◽  
E. E. Stansbury
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Short Range ◽  
Boundary Migration ◽  
Grain Boundary Migration ◽  
Rapid Cooling ◽  
Temperature Range ◽  
Fee Structure ◽  
Domain Coarsening ◽  
Boundary Reaction

The Ni4Mo alloy has a short-range ordered fee structure (α) above 868°C, but transforms below this temperature to an ordered bet structure (β) by rearrangement of atoms on the fee lattice. The disordered α, retained by rapid cooling, can be ordered by appropriate aging below 868°C. Initially, very fine β domains in six different but crystallographically related variants form and grow in size on further aging. However, in the temperature range 600-775°C, a coarsening reaction begins at the former α grain boundaries and the alloy also coarsens by this mechanism. The purpose of this paper is to report on TEM observations showing the characteristics of this grain boundary reaction.

The reaction of amorphous Ni-Nb films with Si in the presence of a native SiO2 layer

1990 ◽  
Vol 48 (4) ◽  
pp. 664-665
Author(s):  
N. Rozhanski ◽  
A. Barg
Keyword(s):  
High Temperature ◽  
Crystallization Temperature ◽  
Diffusion Barriers ◽  
Sio2 Layer ◽  
Si Substrate ◽  
Cross Sectional ◽  
Plan View ◽  
Temperature Range ◽  
Sputter Deposited

Amorphous Ni-Nb alloys are of potential interest as diffusion barriers for high temperature metallization for VLSI. In the present work amorphous Ni-Nb films were sputter deposited on Si(100) and their interaction with a substrate was studied in the temperature range (200-700)°C. The crystallization of films was observed on the plan-view specimens heated in-situ in Philips-400ST microscope. Cross-sectional objects were prepared to study the structure of interfaces.The crystallization temperature of Ni5 0 Ni5 0 and Ni8 0 Nb2 0 films was found to be equal to 675°C and 525°C correspondingly. The crystallization of Ni5 0 Ni5 0 films is followed by the formation of Ni6Nb7 and Ni3Nb nucleus. Ni8 0Nb2 0 films crystallise with the formation of Ni and Ni3Nb crystals. No interaction of both films with Si substrate was observed on plan-view specimens up to 700°C, that is due to the barrier action of the native SiO2 layer.

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