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33 results on '"Kadota, Joji"'

5. Linear polymers with sulfur in the main chain. IV. synthesis of thermotropic liquid-crystalline polythioesters based on 4,4'-biphenyldithiol with excellent adhesive properties

Author

Hirano, Hiroshi, Kadota, Joji, Agari, Yasuyuki, Harada, Toshihiko, Tanaka, Mitsuaki, and Hasegawa, Kiichi

Subjects
Polymers -- Research -- Properties -- Production processes, Engineering and manufacturing industries, Science and technology, Production processes, Research, Properties
Abstract

A series of sulfur-containing linear polythioesters were synthesized from 4,4'-biphenyldithiol (BPT) and bifunctionally aliphatic acyl dichlorides (ACs) by means of polycondensation. Polycondensations of BPT with azelaoyl chloride or sebacoyl chloride chosen as a model reaction system were investigated in several solvents by solution polycondensation, to find an optimal solvent to achieve high molecular weight and quantitative yield. Thus, all the polythioesters from BPT and AC (methylene number of 3-10) were synthesized in chloroform and their structures were confirmed by [1.sup.H]-NMR and Fourier transform infrared spectrophotometer. They were also evaluated by thermogravimetry and differential scanning calorimeter (DSC). Almost all of the BPT, polythioesters exhibited two distinct exothermic and endothermic peaks on first cooling and second heating in their DSC curves, respectively. Polarized microscope (PLM) observation clarified that the higher transition temperatures were isotropic temperatures ([T.sub.i]s). The odd-even effect between [T.sub.i] and the methylene number was observed in these BPT polythioesters. Furthermore, almost all of the polythioesters showed thermotropic liquid-crystalline behavior, as evidenced by a PLM observation. To know the effect of introduction of sulfur on adhesive properties of the polythioester/copper junction, a single lap shear test was carried out in comparison with corresponding 4,4'-biphenyldiol (BPH) polyesters derived from BPH and ACs. It was clarified that the BPT polythioesters have greatly higher adhesive strengths in comparison with the BPH polyesters. POLYM. ENG. SCI., 47:262-269, 2007. © 2007 Society of Plastics Engineers, INTRODUCTION The use of sulfur for organic compounds has mainly been applied to the vulcanization of rubber. In recent years, sulfur came to be used as an important component of [...]

Published
2007

7. A new platinum complex catalyzed reaction involving nucleophilic substitution at the central carbon atom of the pi-allyl ligand

Author

Kadota, Joji, Komori, Shinji, Fukumoto, Yoshiya, and Murai, Shinji

Subjects
Platinum catalysts -- Research, Substitution reactions -- Research, Biological sciences, Chemistry
Abstract

The platinum-catalyzed reaction of 2-chloro-allyl acetate with carbon nucleophiles results in a nucleophilic attack on the central carbon atom. Normally, the nucleophile attacks the terminal carbon. The pK(sub)a of the nucleophile determines which carbon it will attack.

Published
1999

9. Ring-opening polymerization of L-lattice efficiently triggered by an amido-indole. X-ray structure of a complex between L-lactide and the hydrogen-bonding organocatalyst

Author

Koeller, Sylvain, Kadota, Joji, Deffieux, Alain, Peruch, Frederic, Massip, Stephane, Leger, Jean-Michel, Desvergne, Jean-Pierre, and Bibal, Brigitte

Subjects
Amides -- Structure, Amides -- Chemical properties, Hydrogen bonding -- Analysis, Indole -- Chemical properties, Nuclear magnetic resonance spectroscopy -- Usage, Polymerization -- Analysis, Chemistry
Abstract

N-(3,5-Bis(trifluoromethyl)phenyl)-1H-indole-2-carboxamide is an efficient hydrogen-bonding organocatalyst for the ring-opening polymerization of L-lactide and also for controlling the dispersity and molecular weight of the poly(L-lactides). The X-ray structure of the complex between H-bonding organocatalyst and L-lactide has shown a tight H-bonded network between the dimer and L-lactide.

Published
2009

16. (Thio)Amidoindoles and (Thio)Amidobenzimidazoles: An Investigation of Their Hydrogen‐Bonding and Organocatalytic Properties in the Ring‐Opening Polymerization of Lactide

Author

Koeller, Sylvain, primary, Kadota, Joji, additional, Peruch, Frédéric, additional, Deffieux, Alain, additional, Pinaud, Noël, additional, Pianet, Isabelle, additional, Massip, Stéphane, additional, Léger, Jean‐Michel, additional, Desvergne, Jean‐Pierre, additional, and Bibal, Brigitte, additional

Published
2010
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33. (Thio)Amidoindoles and (thio)amidobenzimidazoles: an investigation of their hydrogen-bonding and organocatalytic properties in the ring-opening polymerization of lactide.

Author

Koeller S, Kadota J, Peruch F, Deffieux A, Pinaud N, Pianet I, Massip S, Léger JM, Desvergne JP, and Bibal B

Abstract

The mechanism of the ring-opening polymerization (ROP) of lactide catalyzed by two partner hydrogen-bonding organocatalysts was explored. New amidoindoles 4 a,c, thioamidoindoles 4 b,d, amidobenzimidazoles 5 a,c, and thioamidobenzimidazoles 5 b,c were synthesized and used as activators of the monomer. In the solid state and in solution, compounds 4 and 5 showed a propensity for self-association, which was evaluated. (Thio)Amides 4 and 5 do catalyze the ROP of lactide in the presence of a cocatalyst, tertiary amine 3 a or 3 b, which activates the growing polymer chain through hydrogen-bonding. Reactions were conducted in 2-24 h at 20 degrees C; conversion yields ranged between 22 and 100 %. A detailed study of the intermolecular interactions undertaken between the participating species showed that, as expected, simultaneous weak hydrogen bonds do exist to activate the reagents. Moreover, interactions have been revealed between the partner catalysts 4/5+3. ROP catalyzed by these partner activators is thus governed by multiple dynamic equilibria. The latter should be judiciously adjusted to fine-tune the catalytic properties of (thio)amides and organocatalysts, more generally.

Published
2010
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