Novel thermally stable organo-montmorillonites from phosphonium and imidazolium surfactants

Abdallah, Wissam
Yılmazer, Ülkü
To circumvent the deleterious early decomposition effects of thermally unstable alkyl ammonium-treated montmorillonites when processed with high-melting-point polymers, high thermally stable salts are used as intercalant agents for sodium montmorillonite rich bentonites of Turkish origin, by an ion exchange reaction to produce organo-montmorillonites with enhanced thermal stability. The bentonite clay was purified by sedimentation, resulting in higher cation exchange capacity and thermal stability in comparison to unpurified clay, and then used in the synthesis of six thermally stable organo-montmorillonites by replacing the interlayer inorganic sodium cations with two (alkyl, aryl) phosphonium and four di-(alkyl, aryl) imidazolium surfactant cations. The interlayer spacing of the phosphonium organo-montmorillonites ranged from 1.78 nm to 2.52 nm, while the interlayer spacing of imidazolium organo-montmorillonites ranged between 1.35 nm and 1.45 nm. The effects of chemical structure (chain type), counter ion and alkyl chain length on the thermal stability of the imidazolium salts were investigated.


Enhanced solubility of siloxy-modified polyhedral oligomeric silsesquioxanes in supercritical carbon dioxide
Demirtas, Cansu; Dilek Hacıhabiboğlu, Çerağ (Elsevier BV, 2019-01-01)
Alkyl siloxy functionalization increases the solubility of polyhedral oligomeric silsesquioxanes (POSS) in supercritical carbon dioxide over an order of magnitude compared to its counterpart with fluoroalkyl groups. The studied component, octatrimethylsiloxy POSS also exhibits higher solubility than other previously studied POSS types with various alkyl and methacryl groups. The octatrimethylsiloxy POSS-CO2 solid-vapor equilibrium curves have been constructed at temperatures between 308 and 328 K by measuri...
Theoretical investigation of hydroxytyrosol and its radicals
Erkoc, F; Keskin, N; Erkoç, Şakir (Elsevier BV, 2003-05-05)
The structural and electronic properties of hydroxytyrosol, its three radical isomers, and its three analogues hydroxytyrosol-dihydroxyl isomers have been investigated theoretically by performing semi-empirical self-consistent field molecular orbital theory calculations. The geometry of the systems have been optimized and the electronic properties have been calculated at the level of AMI method.
A theoretical study on the reaction products of quinoline and dimethyl acetylenedicarboxylate
Türker, Burhan Lemi; Yildirir, Y (Elsevier BV, 2004-05-14)
In the literature various structures have been proposed for the products of quinoline and dimethyl acetylenedicarboxylate reaction. In the present study, within the framework of AM1 (RHF) formulism, some light was shed on the mechanism of formation of some of these products.
AM1 treatment of phenylboronic acid esters of glycerol
Türker, Burhan Lemi (Elsevier BV, 2004-05-14)
Phenylboronic acid esters of glycerol, which involve 1,2- and 1,3-sites of glycerol for esterification followed by complex formation with the remaining -OH group of glycerol have been considered for AM1(RHF) type semiempirical quantum chemical calculations, in vacuum as well as in aqueous medium. All the species were found to be stable and exothermic. The stability order among the various species considered was established. 1,2-type ester in vacuum or aqueous medium was found to be more stable than the resp...
Complex-radical cyclocopolymerization of allyl a-(N-maleimido)acetate with styrene and maleic anhydride
Rzaev, ZMO; Salamova, UU; Altindal, S (Wiley, 1997-08-01)
Radical copolymerizations of allyl alpha-(N-maleimido)acetate (AMI) with styrene (D, electron-donor) or maleic anhydride (A, electron-acceptor) were carried out in benzene and/or methyl ethyl ketone (MEK) at 50-70 degrees C in the presence of 2,2'-azoisobutyronitrile (AIBN) as initiator. The structure and properties of copolymers synthesized were derived from IR, chemical, DTA and TGA analyses. Side-chain unsaturation of macromolecules was also proved by the crosslinking effect observed. Kinetic parameters ...
Citation Formats
W. Abdallah and Ü. Yılmazer, “Novel thermally stable organo-montmorillonites from phosphonium and imidazolium surfactants,” THERMOCHIMICA ACTA, pp. 129–140, 2011, Accessed: 00, 2020. [Online]. Available: