THE INTERACTION OF FRIEDEL–CRAFTS CATALYSTS WITH ORGANIC MOLECULES: I. THE CH3COCl:AlCl3 SYSTEM

1959 ◽  
Vol 37 (1) ◽  
pp. 48-53 ◽  
Author(s):  
Denys Cook
Keyword(s):  
Dielectric Constant ◽  
Acetyl Chloride ◽  
Organic Molecules ◽  
Low Dielectric Constant ◽  
Pure Liquid ◽  
Infrared Study ◽  
Low Dielectric ◽  
Donor Acceptor ◽  
High Dielectric ◽  
Chlorine Bond

An infrared study of the liquid complex of aluminum chloride with acetyl chloride has been undertaken. The results indicate that the pure liquid complex is not a simple mixture, but consists of (1) the donor–acceptor complex [Formula: see text] and (2) the ions [CH3CO]+ and [AlCl4]−. A solution of the liquid complex in a solvent of high dielectric constant like nitrobenzene (ε = 36.1) contains both these species, but in a low dielectric constant solvent like chloroform (ε = 5.05) only (1) is present. The carbon–chlorine bond in (1) is modified. The mechanism of Friedel–Crafts ketone synthesis is briefly examined in the light of these results.

Adhesion and Dielectric Strength of Ultra-Low Dielectric Constant PTFE Thin Films

1997 ◽  
Vol 476 ◽  
Author(s):  
C.T. Rosenmaver ◽  
J. W. Bartz ◽  
J. Hammes
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Dielectric Strength ◽  
Low Dielectric Constant ◽  
Thermal Treatments ◽  
Test Results ◽  
Low Dielectric ◽  
Metal Insulator Metal ◽  
Thickness Standard ◽  
High Dielectric

AbstractPrevious work has demonstrated the potential of polytetrafluoroethylene (PTFE) thin films for ULSI applications. The films are deposited from PTFE nanoemulsions. They have an ultra-low dielectric constant of 1.7 to 2.0, a leakage current of less than 1.0 nA/cm2 @ 0.2 MV/cm and a dielectric strength of from 0.5 to 2.4 MV/cm. They are thermally stable (isothermal weight loss < 1.0 %/hr at 450 °C), uniform (thickness standard deviation < 2%), and have excellent gap-fill properties (viscosity of 1.55 cP and surface tension of 18 mN/m). The films are inert with respect to all known semiconductor process chemicals, yet they are easily etched in an oxygen plasma.This paper discusses the processing technology that has been developed to process PTFE films with these properties. Specifically, it addresses two recent discoveries: 1) Good adhesion of spin-coated PTFE to SiO2 surfaces; and 2) high dielectric strength of PTFE thin films spin-coat deposited onto rigid substrates. The adhesion-promoting and thermal treatments necessary to produce these properties are detailed. Stud pull test results and test results from metal-insulator-metal (MIM) capacitor structures are given.

Pulsed DC Magnetron Sputtered Rutile TiO2 films for next generation DRAM capacitors

2013 ◽  
Vol 1561 ◽  
Author(s):  
M.A Jithin ◽  
Lakshmi Ganapathi Kolla ◽  
Navakanta Bhat ◽  
S. Mohan ◽  
Yuichiro Morozumi ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
High Dielectric Constant ◽  
Low Dielectric Constant ◽  
Si Substrate ◽  
Capacitance Density ◽  
Low Dielectric ◽  
Pulsed Dc ◽  
High Dielectric ◽  
Mim Capacitors

ABSTRACTIn this study, synthesis and characterization of rutile-Titanium dioxide (TiO2) thin films using pulsed DC Magnetron Sputtering at room temperature, along with the fabrication and characterization of MIM capacitors have been discussed. XPS and RBS data show that the films are stoichiometric and have compositional uniformity. The influence of electrode materials on electrical characteristics of the fabricated MIM capacitors has been studied. The Al/TiO2/Al based capacitors show low capacitance density (9 fF/μm2) with low dielectric constant (K=25) and high EOT (3.67 nm) due to low dielectric constant TiO2 phase formation on Al/Si substrate. On the other hand, Ru/TiO2/Ru based capacitors show high capacitance density (49 fF/μm2) with high dielectric constant (K=130) and low EOT (0.7nm) values at high frequency (100 KHz) due to high dielectric constant phase (rutile) formation of TiO2, on Ru/Si substrate. Raman spectra confirm that the films deposited on Ru/Si substrate show the rutile phase.

Siloxane Polymers as Low Dielectric Materials for Microelectronics

1995 ◽  
Vol 390 ◽  
Author(s):  
C. P. Wong
Keyword(s):  
Dielectric Constant ◽  
Three Dimensional ◽  
Signal Propagation ◽  
Dielectric Materials ◽  
Propagation Delay ◽  
Dimensional Structure ◽  
Low Dielectric Constant ◽  
Interlayer Dielectric ◽  
Low Dielectric ◽  
High Dielectric

ABSTRACTA modem VLSI device is a complicated three-dimensional structure that consists of multilayer metallization conductor lines which are separated with interlayer-dielectrics as insulation. This VLSI technology drives the IC device into sub-micron feature size that operates at ultra-fast speed (in excess of > 100 MHz). Passivation and interlayer dielectric materials are critical to the device performance due to the conductor signal propagation delay of the high dielectric constant of the material. Low dielectric constant materials are the preferred choice of materials for this reasons. These materials, such as Teflon® and siloxanes (silicones), are desirable because of their low dielectric constant (∈1) = 2.0, 2.7, respectively. This paper describes the use of a low dielectric constant siloxane polymer (silicone) as IC devices passivation layer material, its chemistry, material processes and reliability testing.

Influence of MgO Content on Microstructure and Dielectric Properties in (BaSr)TiO3 Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 85-88
Author(s):  
Lin Hu ◽  
He Ping Zhou ◽  
Hao Xue ◽  
Chun Lai Xu
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Low Dielectric Constant ◽  
Microwave Technology ◽  
Phased Array Antennas ◽  
Strontium Titanium Oxide ◽  
Low Dielectric ◽  
Barium Strontium ◽  
High Dielectric

Barium strontium titanium oxide (BSTO) has great advantages and potentiality for the application of microwave technology. In order to be used in phased array antennas, high dielectric tunability, relatively low dielectric constant and low dielectric loss are required. In this paper, MgO was mixed into BSTO and the microstructure and dielectric properties of MgO-mixed BSTO bulk ceramics were investigated. The mole ratio of Ba and Sr was rather fixed to 5:5 in this study. It is observed that a small amount of MgO (5 wt%) has gone beyond the solubility limits of Mg in BSTO. The dielectric constant and dielectric loss of BSTO ceramics decreased with the increase of the content of MgO mixed. However, the tunability of MgO-mixed BSTO ceramics decreased at the same time. 20wt% MgO-mixed BSTO ceramics exhibits preferable dielectric properties with acceptable tunability.

Preparation and unique dielectric properties of nanoporous materials with well-controlled closed-nanopores

2016 ◽  
Vol 18 (28) ◽  
pp. 19183-19193 ◽  
Author(s):  
Cuijiao Zhao ◽  
Xiaonan Wei ◽  
Yawen Huang ◽  
Jiajun Ma ◽  
Ke Cao ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Porous Structure ◽  
Barrier Properties ◽  
Nanoporous Materials ◽  
Low Dielectric Constant ◽  
Low Dielectric ◽  
High Dielectric Loss ◽  
High Dielectric

Although general porous materials have a low dielectric constant, their uncontrollable opened porous structure results in high dielectric loss and poor barrier properties, thus limiting their application as interconnect dielectrics.

Magnetic nonequivalence in asymmetric phosphorus compounds

1969 ◽  
Vol 47 (17) ◽  
pp. 3167-3171 ◽  
Author(s):  
L. Frankel ◽  
J. Cargioli ◽  
H. Klapper ◽  
R. Danielson
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Dielectric Constant ◽  
Magnetic Resonance ◽  
Chemical Shift ◽  
High Dielectric Constant ◽  
Phosphorus Compounds ◽  
Low Dielectric Constant ◽  
Methyl Groups ◽  
Low Dielectric ◽  
High Dielectric

The nuclear magnetic resonance (n.m.r.) spectra of seven compounds of the type (CH3)P(O)(SCH2SR)(OR′) have been examined as a function of solvent. The resonance pattern of the methylene protons, SCH2S, is strongly solvent dependent. In solvents of low dielectric constant, the methylene protons are magnetically nonequivalent and are observed as the AB part of an ABX spin system, where X is the phosphorus atom. In high dielectric constant medium (DMSO d6) only a well-resolved doublet is obtained indicating magnetic equivalence. When R′ = CH(CH3)2, nonequivalent methyl groups which show analogous solvent effects are observed.Eight compounds of the type (CH3)P(O)(OCH(CH3)2)(X) have been studied. The chemical shift between the magnetically nonequivalent isopropyl methyl groups does not correlate with any simple property of X.

scholarly journals Conformational studies of peptides corresponding to the coeliac-activating regions of wheat α-gliadin

1990 ◽  
Vol 270 (2) ◽  
pp. 313-318 ◽  
Author(s):  
A S Tatham ◽  
M N Marsh ◽  
H Wieser ◽  
P R Shewry
Keyword(s):  
Dielectric Constant ◽  
Structure Prediction ◽  
High Dielectric Constant ◽  
Protein A ◽  
Active Regions ◽  
Low Dielectric Constant ◽  
Type I ◽  
Terminal Part ◽  
Low Dielectric ◽  
High Dielectric

The structures of four peptides corresponding to parts of the coeliac-activating protein A-gliadin were studied by structure prediction and c.d. spectroscopy. Three of the peptides corresponded to parts of the coeliac-activating N-terminal region (residues 3-55, 3-19 and 39-45) and contained two tetrapeptide motifs common to all coeliac-active regions (Pro-Ser-Gln-Gln and Gln-Gln-Gln-Pro). The Pro-Ser-Gln-Gln sequence was also present in the fourth peptide, on the basis of the C-terminal part of the molecule (211-217). These studies showed that beta-reverse turns were the predominant structural feature in all peptides and were predominantly of type I/III in two of the N-terminal peptides and type II in the C-terminal peptide. These turns form when the peptide is dissolved in solvents of low dielectric constant (trifluoroethanol) and high dielectric constant (water and iso-osmotic saline), although their presence in the N-terminal peptides may be masked in the latter solvents due to equilibrium with a poly-L-proline II structure favoured at lower temperatures.

scholarly journals High and Low Dielectric Constant Materials

1999 ◽  
Vol 8 (2) ◽  
pp. 26-30
Author(s):  
Rajenda Singh ◽  
Richard K. Ulrich
Keyword(s):  
Dielectric Constant ◽  
Integrated Circuits ◽  
High Dielectric Constant ◽  
Low Dielectric Constant ◽  
Low Dielectric ◽  
A Value ◽  
Silicon Integrated Circuits ◽  
Low Dielectric Constant Materials ◽  
High Dielectric ◽  
Silicon Based

Silicon-based dielectrics (SiO2, Si3N4, SiOxNy etc.) have been widely used as the key dielectrics in the manufacturing of silicon integrated circuits (ICs) and virtually all other semiconductor devices. Dielectrics having a value of dielectric constant k × 8.854 F/cm more than that of silicon nitride (k > 7) are classified as high dielectric constant materials, while those with a value of k less than the dielectric constant of silicon dioxide (k < 3.9) are classified as the low dielectric constant materials. The minimum value of (k) is one for air. The highest value of k has been reported for relaxor ferroelectric (k = 24,700 at 1 kHz).

Dielectric phase transition of an A2BX4-type perovskite with a pentahedral to octahedral transformation

2020 ◽  
Vol 49 (7) ◽  
pp. 2218-2224 ◽  
Author(s):  
Siqian Chai ◽  
Jianbo Xiong ◽  
Yongshen Zheng ◽  
Rongchao Shi ◽  
Jialiang Xu
Keyword(s):  
Phase Transition ◽  
Dielectric Constant ◽  
Room Temperature ◽  
High Dielectric Constant ◽  
Low Dielectric Constant ◽  
Dielectric Phase ◽  
Low Dielectric ◽  
High Dielectric

The as-synthesized 2D perovskite [C5H12N]2PbCl4 undergoes an above-room-temperature dielectric phase transition with a reversible pentahedral to octahedron transformation and a high dielectric constant being over twice of the low dielectric constant.

scholarly journals SOLVENT EFFECT ON IODIDE EXCHANGE

1951 ◽  
Vol 29 (9) ◽  
pp. 790-803 ◽  
Author(s):  
R. D. Heyding ◽  
C. A. Winkler
Keyword(s):  
Dielectric Constant ◽  
Dissociation Constants ◽  
Hydrogen Iodide ◽  
Low Dielectric Constant ◽  
Specific Rate ◽  
Iodide Ions ◽  
Low Dielectric ◽  
The Individual ◽  
High Dielectric ◽  
Triple Ion

The exchange of iodine between hydrogen iodide and n-butyl iodide has been studied in several organic solvents. In solvents of high dielectric constant (methanol, ethanol, n-butanol), exchange occurred by reaction of iodide ions with butyl iodide. In solvents of low dielectric constant (n-hexanol, n-dodecanol, acetic acid), it appeared that exchange also occurred between butyl iodide and the associated IHI− triple ion. Orders of magnitude of the individual specific rate constants have been calculated, using approximate values for the dissociation constants of hydrogen iodide. The rate constant – dielectric constant relation developed by Laidler and Eyring for ion – neutral molecule reactions appears to hold for exchange in homologous solvents, but does not seem to represent the effect of nonhomologous solvents. This discrepancy and the small differences observed in activation energies for the various exchanges may be due to solvation effects.

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