Spectroscopic studies of an ambient-pressure process for the selective hydrogenation of polybutadienes

Edwards, Howell G. M.; Farwell, Dennis W.; Johnson, A. F.; Lewis, Ian R.; Webb, N.; Ward, N. J.

doi:10.1021/ma00028a005

Cited by 26 publications

(14 citation statements)

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“…This product can undergo an ionic or radical addition to yield sulfones and sulfides or, still, it can react with the double bond of pendant vinyl groups or unsaturated bonds along the polymer structure 5, 10, 18, 19. Their presence can be monitored by FTIR and 1 H‐NMR analysis 10, 18, 20, 21. Typical bands in FTIR analysis are visualized at 1318 cm −1 and 1145 cm −1 , corresponding to the asymmetric and symmetric stretching of the SO 2 group, at 811 cm −1 associated with CH rocking vibration, and at 1020 cm −1 , attributed to the p ‐tolyl aromatic ring.…”

Section: Resultsmentioning

confidence: 99%

Influence of 1,2 units content on the hydrogenation of polydienes by TSH

Santin

Jacobi

Schuster

2010

J of Applied Polymer Sci

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The influence of 1,2 vinyl content on hydrogenation of SBR and BR rubbers with high molecular weight by a noncatalytic method using p-toluenesulfonylhydrazide (TSH) as reagent was investigated. Results show an increase of hydrogenation percentage with molar ratio of the reagents, temperature, and reaction time. The degree of hydrogenation depends strongly on the microstructure of the rubber mainly on the amount of 1,2 content. Infrared spectroscopy (FTIR) was used to confirm the microstructural characteristics of the hydrogenated rubbers. The degree of hydrogenation was determined by iodometry method and 1 H-NMR analysis. The change in the thermal behavior of hydrogenated rubbers was followed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), which showed a difference in flexibility chain and thermal stability. The kinetic studies demonstrate that the diimide reduction follows a firstorder reaction with respect to olefin substrate.

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Section: Resultsmentioning

confidence: 99%

Influence of 1,2 units content on the hydrogenation of polydienes by TSH

Santin

Jacobi

Schuster

2010

J of Applied Polymer Sci

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“…The unsaturated double bonds in UPEEs were reduced using TSH to yield PBHBs as shown in Scheme 2. TSH has been used for the reduction of unsaturated double bonds in polybutadienes and other polymers carrying unsaturated bonds before [7][8][9][10][11][12][13][14][15][16].…”

Section: Synthesis Of Pbhbsmentioning

confidence: 99%

A new addition to the family of polyesters—Synthesis and characterization of novel (alternating) poly(ether ester)s, poly(butylene 3-/4-hydoxy benzoate)s

Parthiban

Choo

2012

J Polym Res

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Novel, predominantly alternating poly(ether ester)s, poly(butylene-3/4-hydroxy benzoate)s (PBHB)s were synthesized by the hydrogenation of the corresponding unsaturated polymers obtained by forming ether and ester linkages under one pot conditions. The ether substitution caused a reduction in glass transition temperature, T g . The melting transition was also lowered by more than 100°C compared to poly(butylene terephthalate) as studied by the differential scanning calorimetry (DSC). Crystallization was observed during heating as well as cooling in the DSC studies. Wide angle X-ray diffraction (WAXRD) analysis also indicated that PB-4-HB was semicrystalline in nature. The thermal stability of hydrogenated polymer was better than that of the unsaturated polymer.

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“…Device fabrication is a demanding test for polymer materials, and this experience gave me a greater familiarity than I necessarily desired with cross-linking issues. The limitations of then-current, forcing, diimide and heterogeneous reduction methods were becoming evident (23,24), while the potential opportunities of homogeneous hydrogenation methods (25) were familiar to me from my Ph.D. background with Brian James. The structural resemblance between the new Grubbs catalyst and known Ru hydrogenation catalysts (five-coordinate, square pyramidal complexes with an apical, high-trans-influence active site) led me to wonder about the possibility of transforming the metathesis-active ruthenium alkylidenes into hydrogenation-active ruthenium hydrides (Scheme 1).…”

Section: Tandem Catalysismentioning

confidence: 99%

Inside the black box — Perspectives on transformations in catalysis

Fogg¹

2008

Can. J. Chem.

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Tandem catalysis and olefin metathesis are powerful tools in the development of sustainable synthetic practices. This Award Lecture describes our advances in designing new tandem metathesis-hydrogenation methodologies for the synthesis of "designer materials" and Ru-pseudohalide metathesis catalysts that amplify opportunities for tuning catalyst activity, selectivity, and lifetime. Also discussed is the operation of a previously unrecognized oligomerizationbackbiting pathway in ring-closing metathesis of conformationally flexible α,ω-dienes, which has important implications for the sustainable synthesis of medium and large rings.Résumé : La catalyse en tandem et la métathèse d'oléfines sont de puissants outils dans le développement de pratiques synthétiques renouvelables. Dans cette présentation on décrit les développements réalisés dans nos laboratoires dans la conception de nouvelles méthodologies de tandems catalyse/métathèse qui permettent d'obtenir des produits ciblés ainsi que des catalyseurs de métathèse à base de ruthénium et d'un pseudohalogène qui amplifient les opportunités d'ajustement de l'activité, de la sélectivité et du temps de vie du catalyseur. On discute aussi de l'opération d'une voie réactionnelle antérieurement inconnue d'oligomérisation "par transfert de chaîne interne" dans la métathèse de la fermeture de cycle de α,ω-diènes conformationnellement flexibles qui présente d'importantes implications pour la synthèse renouvelable de cycles de tailles moyennes ou grandes.Mots-clés : catalyse en tandem, chimie verte, métathèse d'oléfine, métathèse de fermeture de cycle, mécanisme.[Traduit par la Rédaction] Fogg 941

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Spectroscopic studies of an ambient-pressure process for the selective hydrogenation of polybutadienes

Cited by 26 publications

References 1 publication

Influence of 1,2 units content on the hydrogenation of polydienes by TSH

Influence of 1,2 units content on the hydrogenation of polydienes by TSH

A new addition to the family of polyesters—Synthesis and characterization of novel (alternating) poly(ether ester)s, poly(butylene 3-/4-hydoxy benzoate)s

Inside the black box — Perspectives on transformations in catalysis

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