Quaternary Alkyl Ammonium Cations Research Articles

2001. A Clay Odyssey, Proceedings of the 12th International Clay Conference, Bahia Blanca, Argentina, July 2001 edited by Eduardo A. Domínguez, Graciela R. Mas and Fernanda Cravero. Elsevier, Amsterdam, The Netherlands, 2003; xiii + 659 pages. [ISBN: 0-444-50945-3]. Price: $200

The 12th International Clay Conference of the Association Internationale pour l’Etude des Argiles (AIPEA) was held at Universidad Nacional del Sur, Bahia Blanca from July 22–28, 2001. During this conference 235 oral and poster papers were presented and this publication contains 85 of those papers. The proceedings are organized under seven themes, namely, Special Lectures and Keynotes, Clay in Geology, Soil Mineralogy, Applied Clay Science, Mineral Structure and Investigation Methods, Teaching Soil Mineralogy and International Symposium on Activated Clays. Most of the papers are eight pages long including figures, tables and references. Section 1 (Special Lectures and Keynotes) consists of four papers presented by the invited speakers at the conference. Haydn Murray provides an overview of the industrial application of kaolins, smectites, palygorskite, sepiolite and some other clays. The paper highlights the importance of the fundamental knowledge of the structure and composition of clay minerals for their industrial applications. R. R. Andreis describes sedimentary deposits and their clay mineralogy over crystalline rocks in the Tandilla System in Buenos Aires Province of Argentina. M. Dondi covers the recent advances in technology of tile making and compositional requirements of clay minerals for making tiles. He observes that there is an increase in demand for low-Fe and low-Ti ball clays in porcelain stoneware and stresses the need for new treatments to lower the Fe and Ti contents of ball clays. G.J. Churchman and C. Volzone show the importance of clays in the environmental context using the examples of two activated clays to adsorb organic compounds and gases. They also discuss some other applications including the effects of exchangeable Na on the protein adsorption capacity of smectites and the use of activated clays with long-chain quaternary alkylammonium cations to adsorb non-ionic organic compounds. Section II (Clays in Geology) has 19 papers mostly from …

Polyolefin nanocomposites formed by melt compounding and transition metal catalyzed ethene homo- and copolymerization in the presence of layered silicates

Nanocomposites of high density polyethylene (HDPE), linear low density polyethylene (LLDPE) and highly branched polyethylene rubbers were prepared both by means of melt compounding and ethene homo- and copolymerization in the presence of layered silicates which were rendered organophilic via ion exchange with various quaternary alkyl ammonium cations. In comparison to melt compounding, in-situ ethene homo- and copolymerization, catalyzed with MAO-activated zirconocene (MBI), nickel (DMN) and palladium (DMPN) catalysts, proved more effective in nanocomposite formation, as evidenced by larger interlayer spacings and formation of exfoliated anisotropic nanosilicates with high aspect ratio.

A Robust Platinum Carbonyl Cluster Anion [Pt3(CO)6]52-Encapsulated in an Ordered Mesoporous Channel of FSM-16: FTIR/EXAFS/TEM Characterization and Catalytic Performance in the Hydrogenation of Ethene and 1,3-Butadiene

A robust trigonal prismatic cluster anion [Pt3(CO)6]52- (νCO = 2078, 1878 cm-1; λmax = 405 and 702 nm; R1(Pt−Pt) = 2.68 A (CN = 2.0); R2(Pt−Pt) = 3.08 A (CN = 1.5)) is selectively synthesized in the ordered hexagonal channel of FSM-16 by the reductive carbonylation of H2PtCl6/NR4+/FSM-16 under a CO + H2O atmosphere at 323 K. The Pt cluster anion extracted in THF solution by cation metathesis was identified as [Pt3(CO)6]52- by FTIR and UV−vis spectroscopic data. TEM observation showed that [Pt3(CO)6]52- was uniformly dispersed and aligned in the mesoporous channels of FSM-16. The Pt15 cluster anions formed in FSM-16 were relatively stabilized by the coimpregnated quaternary alkylammonium cations as NR4+ in the following order for the alkyl groups: butyl > ethyl > methyl, methyl viologen (MV) > hexyl ≫ no countercations. The EXAFS and FTIR studies demonstrated that [Pt3(CO)6]52- in FSM-16 was transformed by the controlled removal of CO at 300−343 K into the partially decarbonylated Pt15 cluster (R1(Pt−Pt) ...

New organo-montmorillonite complexes with hydrophobic and hydrophilic functions

Quaternary alkylammonium cations (R4N+) with different molecular structures were intercalated into layered aluminosilicate, Na+-montmorillonite (M), by ion exchange reaction. Four kinds of R4N+ molecular ions, [(CH3(CH2)17)xN(CH3)4 − x]+ with x = 1 (ODTM) and x = 2 (DMDS) and [(CH3(CH2)15COO(CH2)2)xN(CH3)(CH2CH2OH)3 − x]+ with x = 1 (DHMC) and x = 2 (DCEM), were used as intercalants. The relative dispersibility of intercalated R4N+M samples in polar and nonpolar solvents were evaluated on the basis of viscosity. Even in an aqueous solution, the DHMC-M and DCEM-M complexes, exhibited good dispersibility due to the hydrophilic functional groups in the organic cations. On the other hand, the DMDS-M and ODTM-M complexes containing only aliphatic long chain showed enhanced dispersibility in nonpolar solvents like n-hexane.

Anion Distributions in Sodium Silicate Solutions. Characterization by29SI NMR and Infrared Spectroscopies, and Vapor Phase Osmometry

Soluble silicates are complex mixtures of silicate anions. The larger anions are two- or three-dimensional condensation products of silicate monomer, SiO4-4. In more siliceous silicate solutions, i.e., SiO2:Na2O ratio >2.0, some of the silicate condenses to polymeric (colloidal) silica. Negative charges on the anions are balanced by protons or by cations, typically alkali metal or quaternary alkylammonium cations. The distribution of these anions varies with the concentration of dissolved silicate solids, the relative molar concentrations of cations and silica, and to a lesser extent, trace impurities. 29Silicon NMR spectroscopy of silicate solutions has been a powerful method for studying the connectivity of silicon and oxygen atoms in silicate solutions. In this paper we will show how variations in silicate band shape and peak location in the mid-infrared spectrum from 700 to 1300 cm-1 depend on concentration and silica:alkali ratio. We will interpret the infrared data in consonance with NMR results. We will also relate these variations in anion distribution to the average molecular weight of silicate solutions.

Hydrothermal synthesis of ordered ultra—-large pore molecular sieves

Semiconductor nanoparticles assembled within a zeolite is an example to create quantum confined system. The present studies are focused on the hydrothermal synthesis of ultra-large pore (ULP) molecular sieves. Molecular sieves can be prepared under hydrothermal condition from Catapal alumna, aluminosilicate, silicate and ethylsilicate gels respectively, under carefully chosen conditions of pH, temperature and crystallization time. It is very important to note that co-added alkali metal cations, quaternary alkylammonium cation and surfactant species function as charge balancing agent, spacing-filling and structure-directing to obtain a ULP molecular sieve. TEM and electron diffraction pattern conform the periodicity of the structure. X-ray diffraction pattern of the powder sample shows that there are two peaks in the low-angle 2Θ, the larger d value is 47.4Å. The formation of these materials takes place by means of a liquid-crystal templating mechanism is also discussed.

Syntheses of Aromatic Bridged Cryptophanes and their Complexing Abilities with Alkyl Ammonium Cations

Abstract Several aromatic bridged cryptophanes were successfully synthesized. p-Xylene bridged cryptophane Anti-3 was prepared by the direct trimerization of α,α'-bis[4-hydroxymethyl-2-methoxyphenoxy]-p-xylene. The synthesis of o-xylene bridged cryptophane Anti-8 was carried out by the direct trimerization and/or the stepwise method from vanillyl alcohol. The o-[4,5-bis-(methoxycarbonyl)]xylene bridged cryptophanes Anti-15a and Syn-15b were also prepared by the stepwise method from vanillyl alcohol. Anti-3 was capable of complexing with almost all the quaternary alkylammonium cations among the primary, secondary, tertiary and quaternary ammonium cations, and selectively prefered to complex with the NEt3Me+ cation as a guest. From the complexation of the o-xylene bridged cryptophanes Anti-8, and the analogs Anti-15a and Syn-15b with the NMe4 + cation, the cryptophanes Anti-8 and Syn-15b were confirmed to complex with the guest cation, however, Anti-15a was not confirmed to be included.

Extraction chromatography of common anions in liquid-liquid anion exchange systems. Part. III. Monobasic aliphatic organic acids and their sodium salts as eluants

The chromatographic behaviour of anions on paper strips treated with tri-n-octylamine (TOA) salts or Aliquat 336 and developed with aqueous solutions of acetic, formic, monochloroacetic or trifluoroacetic acids and their sodium salts was investigated. Liquid-liquid extraction of organic acids by 0.1 M solution of TOA in benzene as well as the anion exchange between benzene solutions of TOA salts or Aliquat 336 (in acetate form) in benzene and aqueous solutions of sodium halides was also studied. It was found that extraction increases in the following order of the acids: CH3COOOH<HCOOH<CH2CICOOH<CF3COOH; the relative affinity of organic anions to the quaternary alkyl-ammonium cation also increase in a similar order. The extraction of acid in excess over the amount necessary to neutralize the amine was observed for all four acids. The RF values of anions investigated depend markedly on the type of organic acids or their salts and their concentration in the mobile phase. Halide ions are more strongly retained on paper treated with Aliquat 336 as compared with TOA salts. The chromatographic systems investigated offer many possibilities to separate various anion mixtures.

Permeability of the Abdominal Nerve Cord of the American Cockroach, Periplaneta Americana L. to Quaternary Ammonium Salts

ABSTRACT The influx and efflux of two series of quaternary alkylammonium cations in the abdominal nerve cord of the American cockroach have been studied. The data are interpreted as showing that increasing liposolubility tends to increase penetration, and increasing size (with respect to the smallest cross-sectional area) decreases it. The influx rates of the quaternary alkylammonium cations into the cockroach central nervous system (C.N.S.) is 2-7 times lower than Na+ when equimolar concentrations are compared. Acetylcholine penetrates into the C.N.S. rapidly due to its metabolism, since in the presence of eserine its influx rate becomes similar to that of the analogous alkylammonium cation which is unmetabolized. The alkylammonium cations that penetrate into the C.N.S. appear to be distributed into fast and slow pools, as judged by their relative rates of efflux. These may represent the distribution of cations between extracellular and intracellular spaces or possibly free and bound cations in the extracellular spaces. Although the alkylammonium cations penetrate the C.N.S., they apparently encounter a regulatory system that discriminates against large size, positive charge and polarity. This research project was financed in part by NIH Grant GM 07804-06.