4991-22-4Relevant academic research and scientific papers
A supramolecular nematic phase in sulfonated polyaramides
Viale, Sebastien,Best, Adam S.,Mendes, Eduardo,Jager, Wolter F.,Picken, Stephen J.
, p. 1596 - 1597 (2004)
A water-soluble polyaramide sulfo-invert-PPTA surprisingly, already at a molecular weight of 10,000 g mol-1, exhibits a nematic liquid crystalline phase in water at very low polymer concentrations, around 1-2wt%, indicating that supramo lecular assemblies of molecules are the building blocks of the nematic phase.
A sulfonated polyaramide: Stir-induced chirality in its aqueous solution
Okano, Kunihiko,Machida, Kanami,Yamashita, Takashi
, p. 750 - 752 (2012)
We demonstrated that aqueous solutions containing a sulfonated polyaramide exhibited stir-induced chirality detected by circular dichroism (CD) spectroscopy. This phenomenon can be visualized as dynamics of supramolecular structure comprising hydrogen-bonded polyaramides. We further show that the sign of the CD response can be tuned using vortex direction, stirring-rate, and concentration.
Synthesis and formation of a supramolecular nematic liquid crystal in poly(p-phenylene-sulfoterephthalamide)-H2O
Viale, Sebastien,Li, Nan,Schotman, Anton H. M.,Best, Adam S.,Picken, Stephen J.
, p. 3647 - 3652 (2005)
The formation of lyotropic solutions in water has yet to be reported for polyaramides. In this work, we investigate the synthesis and properties of a water-soluble polyaramid via the inclusion of a sulfonated monomer in the backbone of the polymer chain. Using sulfonated terephthalic acid (sTA) together with a diamine and a diisocyanate enables us to produce a lyotropic water-soluble polyaramid poly(p-phenylene-sulfoterephthalamide). Two different synthetic routes are presented: (1) the reaction between sTA and p-phenylene diisocyanate (PPDI) and (2) the reaction of activated sTA using triphenyl phosphite and p-phenylenediamine (PPD). Polymers with various molar masses up to 15 000 g mol-1 using both methods have been obtained. We have examined the optimal reaction conditions for the synthesis of these polymers, in particular the effect of reaction temperature, concentration of monomers and reactants, type of counterions, and solvents. The polymers obtained are mostly soluble in water, up to high concentration (10 wt % without an alkali counterion on the sulfonic acid group), and surprisingly lyotropic nematic behavior has been observed independent of the molar mass of the polymer. The phase diagram of these materials in water has been investigated, and the lyotropic phase has been characterized using optical polarized microscopy.
PROCESS FOR PREPARING 1.1.3-TRIOXO-1.2-BENZOTHIAZOLE-6-CARBOXAMIDE
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Page/Page column 20; 21, (2017/07/14)
A process for preparing, 1,1,3-Trioxo-l,2-benzothiazole-6-carboxamide of formula (I) comprising: reacting 2-chlorosulfonyl-terephthalic acid dialkyl ester of formula (II) with ammonia (N H3) or ammonium containing-salt; wherein R represents a b
Towards acid MOFs-catalytic performance of sulfonic acid functionalized architectures
Juan-Alcaniz, Jana,Gielisse, Robin,Lago, Ana B.,Ramos-Fernandez, Enrique V.,Serra-Crespo, Pablo,Devic, Thomas,Guillou, Nathalie,Serre, Christian,Kapteijn, Freek,Gascon, Jorge
, p. 2311 - 2318 (2013/09/02)
In this work, the inclusion of free sulfonic acid groups in highly stable MOFs is explored. The synthesized catalysts have been applied in a model esterification reaction. Two metal organic frameworks bearing sulfonic acid moieties are investigated: HSO3-MIL-101(Cr) synthesized following different approaches and a new structure based on HSO3-bdc and Zr. The acidic properties, catalytic performance, deactivation and stability of the different structures are critically evaluated. In the case of MIL-101(Cr), deactivation of the sulfonic groups via formation of butanol sulfonic esters has been observed. Due to the strong interaction between -SO3 - and the Cr open metal site where usually fluorine (F-) is located in the structure, the HSO3-MIL-101(Cr) catalysts are not stable under acidic regeneration conditions. When using Zr as a metal node, a new and stable sulfonic acid containing porous structure was synthesized. This structure showed high activity and full re-usability in the esterification of n-butanol with acetic acid. In this case, deactivation of the catalyst due to sulfonic ester formation could be reversed by reactivation under acidic conditions. The Royal Society of Chemistry 2013.
