scholarly journals Effects of Temperature and of Mixing on Dielectric Constants of Several Organic Solvents

1969 ◽  
Vol 42 (12) ◽  
pp. 3578-3580 ◽  
Author(s):  
Etsuo Niki ◽  
Yoshio Kamiya ◽  
Nobuto Ohta
Keyword(s):  
Organic Solvents ◽  
Dielectric Constants ◽  
Effects Of Temperature

Organo-Soluble, Segmented Rigid-Rod Polyimides: Synthesis and Properties

1991 ◽  
Vol 227 ◽  
Author(s):  
F. W. Harris ◽  
S. L. C. Hsu ◽  
C. J. Lee ◽  
B. S. Lee ◽  
F. Arnold ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Expansion ◽  
Glass Transition ◽  
Oxidative Stability ◽  
Organic Solvents ◽  
Dielectric Constants ◽  
Glass Transition Temperatures ◽  
Thermal Expansion Coefficients ◽  
Rigid Rod ◽  
Expansion Coefficients

ABSTRACTSeveral segmented, rigid-rod polyimides have been prepared that are soluble in organic solvents in their fully imidized form. The polymers were prepared from commercial dianhydrides and 2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl (TFMB). Their intrinsic viscosities ranged from 1.0 to 4.9 dL/g. Tough, colorless films could be cast from m-cresol solutions at 100°C. The polymers had glass transition temperatures (Tgs) above 275°C and displayed outstanding thermal and thermo-oxidative stability. Fibers were prepared from the 3,3′,4,4′-tetracarboxybiphenyl dianhydride (BPDA) based polymers that had moduli of 130 GPa and tensile strengths of 3.2 GPa. The thermal expansion coefficients and dielectric constants of thin films (20–25 μm) of the polymers were as low as −2.40×10−6 and 2.5, respectively.

Dissociation of C6F5SO3Li in two organic solvents with different dielectric constants: a Raman spectroscopic study

2007 ◽  
Vol 38 (12) ◽  
pp. 1570-1576 ◽  
Author(s):  
G. Hirankumar ◽  
C. Iojoiu ◽  
F. Alloin ◽  
J. Y. Sanchez ◽  
T. Pagnier
Keyword(s):  
Spectroscopic Study ◽  
Organic Solvents ◽  
Dielectric Constants ◽  
Raman Spectroscopic ◽  
Raman Spectroscopic Study

Solvent dependent intramolecular excimer emission of di(1-pyrenyl)silane and di(1-pyrenyl)methane derivatives

RSC Advances ◽  
2015 ◽  
Vol 5 (8) ◽  
pp. 5846-5849 ◽  
Author(s):  
Shin-ichi Kondo ◽  
Yuka Taguchi ◽  
Yi Bie
Keyword(s):  
Organic Solvents ◽  
Dielectric Constants ◽  
Excimer Emission ◽  
Polar Organic Solvents ◽  
Intramolecular Excimer

Di(1-pyrenyl)silane and methane derivatives showed unprecedented intramolecular excimer emission in polar organic solvents such as DMSO and the ratio of excimer/monomer emissions strongly depends on the dielectric constants of the solvents.

scholarly journals Effects of Organic Solvents on the Organosolv Pretreatment of Degraded Empty Fruit Bunch for Fractionation and Lignin Removal

2021 ◽  
Vol 13 (12) ◽  
pp. 6757
Author(s):  
Danny Wei Kit Chin ◽  
Steven Lim ◽  
Yean Ling Pang ◽  
Chun Hsion Lim ◽  
Siew Hoong Shuit ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Organic Solvents ◽  
Value Added ◽  
Poor Performance ◽  
Empty Fruit Bunch ◽  
Organosolv Pretreatment ◽  
Alkaline Catalyst ◽  
Different Types ◽  
Effects Of Temperature ◽  
Mild Temperature

Empty fruit bunch (EFB), which is one of the primary agricultural wastes generated from the palm oil plantation, is generally discharged into the open environment or ends up in landfills. The utilization of this EFB waste for other value-added applications such as activated carbon and biofuels remain low, despite extensive research efforts. One of the reasons is that the EFB is highly vulnerable to microbial and fungi degradation under natural environment owning to its inherent characteristic of high organic matter and moisture content. This can rapidly deteriorate its quality and results in poor performance when processed into other products. However, the lignocellulosic components in degraded EFB (DEFB) still largely remain intact. Consequently, it could become a promising feedstock for production of bio-products after suitable pretreatment with organic solvents. In this study, DEFB was subjected to five different types of organic solvents for the pretreatment, including ethanol, ethylene glycol, 2-propanol, acetic acid and acetone. The effects of temperature and residence time were also investigated during the pretreatment. Organosolv pretreatment in ethylene glycol (50 v/v%) with the addition of NaOH (3 v/v%) as an alkaline catalyst successfully detached 81.5 wt.% hemicellulose and 75.1 wt.% lignin. As high as 90.4 wt.% cellulose was also successfully retrieved at mild temperature (80 °C) and short duration (45 min), while the purity of cellulose in treated DEFB was recorded at 84.3%. High-purity lignin was successfully recovered from the pretreatment liquor by using sulfuric acid for precipitation. The amount of recovered lignin from alkaline ethylene glycol liquor was 74.6% at pH 2.0. The high recovery of cellulose and lignin in DEFB by using organosolv pretreatment rendered it as one of the suitable feedstocks to be applied in downstream biorefinery processes. This can be further investigated in more detailed studies in the future.

scholarly journals Characteristics of nearly dry enzymes in organic solvents: implications for biocatalysis in the absence of water

2004 ◽  
Vol 359 (1448) ◽  
pp. 1299-1307 ◽  
Author(s):  
Douglas S. Clark
Keyword(s):  
Organic Solvents ◽  
Protein Interactions ◽  
Active Site ◽  
Enzymatic Reaction ◽  
Solvent Polarity ◽  
Kinetic Studies ◽  
Immobilized Enzymes ◽  
Dielectric Constants ◽  
Electrostatic Model ◽  
Wide Range

We have examined enzymes in nearly anhydrous organic solvents spanning a wide range of dielectric constants using a combination of electron paramagnetic resonance (EPR) spectroscopy, molecular dynamics simulations, high–pressure kinetic studies and the electrostatic model of Kirkwood. This approach enabled us to investigate the relationship between catalytic activity, protein flexibility and solvent polarity for an enzymatic reaction proceeding through a highly polar transition state in the near absence of water. Further insights into water–protein interactions and the involvement of water in enzyme structure and function have been obtained by EPR and multinuclear nuclear magnetic resonance studies of enzymes suspended and immobilized in organic solvents with and without added water. In these systems, correlations were observed between the water content and enzyme activity, flexibility, and active–site polarity, although the structural properties of suspended and immobilized enzymes differed markedly. These results have helped to elucidate the role of water in molecular events at the enzymic active site leading to improved biocatalysis in low–water environments.

Effects of organic additives and temperature on the structures and morphologies of calcium carbonate crystals in the presence of cetyltrimethylammonium bromide

2008 ◽  
Vol 23 (3) ◽  
pp. 200-203
Author(s):  
Yinxiao Du ◽  
Haixing Hou ◽  
Fanguang Zeng
Keyword(s):  
Calcium Carbonate ◽  
Organic Solvents ◽  
Cetyltrimethylammonium Bromide ◽  
Precipitation Reaction ◽  
Organic Additives ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Structure And Morphology ◽  
Effects Of Temperature ◽  
Diffraction Patterns

Calcium carbonate crystals were prepared via a simple precipitation reaction of sodium carbonate with calcium chloride from mixed solutions of various amphiphilic organic solvents and water in the presence of cetyltrimethylammonium bromide at 25 and 60 °C. Our analysis shows that amphiphilic organic solvents and temperature have large influences on the structure and morphology of CaCO3. X-ray diffraction patterns show that single-phase hexahedral calcite was formed at 25 °C, and orthorhombic aragonite was obtained at 60 °C. Mixtures of major amounts of long aragonite crystals and minor amounts of calcite particles were also obtained at 60 °C in the methanol and the acetone solutions. Scanning electron microscopy images show that CaCO3 particles and aggregates with various morphologies, such as large solid and hollow hexahedral crystals and small round granules of calcite as well as glass-like and wheat-like aggregates of aragonite, were obtained depending on the experimental conditions. Based on the experimental results, a conclusion on the effects of temperature and amphiphilic organic solvents on the crystal structure and morphology are made.

Electron microscopy studies of PZT ferroelectric film capacitor structures

1992 ◽  
Vol 50 (2) ◽  
pp. 1364-1365
Author(s):  
V. Kaushik ◽  
P. Maniar ◽  
J. Olowolafe ◽  
R. Jones ◽  
A. Campbell ◽  
...  
Keyword(s):  
Electric Fields ◽  
Sol Gel ◽  
Ferroelectric Material ◽  
Dielectric Constants ◽  
Dielectric Films ◽  
Lead Zirconium Titanate ◽  
Si Substrate ◽  
Film Capacitor ◽  
Pzt Films ◽  
High Dielectric

Lead zirconium titanate films (Pb (Zr,Ti) O3 or PZT) are being considered for potential application as dielectric films in memory technology due to their high dielectric constants. PZT is a ferroelectric material which shows spontaneous polarizability, reversible under applied electric fields. We report herein some results of TEM studies on thin film capacitor structures containing PZT films with platinum-titanium electrodes.The wafers had a stacked structure consisting of PZT/Pt/Ti/SiO2/Si substrate as shown in Figure 1. Platinum acts as electrode material and titanium is used to overcome the problem of platinum adhesion to the oxide layer. The PZT (0/20/80) films were deposited using a sol-gel method and the structure was annealed at 650°C and 800°C for 30 min in an oxygen ambient. XTEM imaging was done at 200KV with the electron beam parallel to <110> zone axis of silicon.Figure 2 shows the PZT and Pt layers only, since the structure had a tendency to peel off at the Ti-Pt interface during TEM sample preparation.

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