Naslov
Polymerization and depolymerization of 1, 4- dinitrosobenzene

Autori
Bibulić, Petar ; Rončević, Igor ; Varga, Katarina ; Mihalić, Zlatko, Vančik, Hrvoj

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
24. hrvatski skup kemičara i kemijskih inženjera : Knjiga sažetaka / Ukić, Šime ; Bolanča, Tomislav - Zagreb : Hrvatsko društvo kemijskih inženjera i tehnologa (HDKI), 2015, 159-159

ISBN
978-953-6894-54-3

Skup
24. hrvatski skup kemičara i kemijskih inženjera

Mjesto i datum
Zagreb, Hrvatska, 21.04.2015. - 24.04.2015

Vrsta sudjelovanja
Poster

Vrsta recenzije
Domaća recenzija

Ključne riječi
polymerization ; nitroso ; FMO ; DFT ; kinetics ; solid-state ; phase transformation

Sažetak
Polymerization 1, 4-dinitrosobenzene was examined to gain a deeper understanding of solid-state reactions. The experimental part included the study of depolymerization and low temperature polymerization of 1, 4-dinitrosobenzene in the solid state by IR spectroscopy. The dissociation of azodioxide bonds was induced either by 254 nm UV irradiation at cryogenic temperatures or by sublimation. Monomers started to form azodioxy bonds at around 150 K. While E-polymers were obtained from monomers prepared by UV photodissociation, Z-forms were detected in samples prepared by sublimation and subsequent deposition on a CsI surface. Because Z-forms isomerized to more stable E polymers above 150 K, these isomers are probably kinetically stabilized by interactions with alkali halide surface. Since polymerization is accompanied by phase transition, a non-linear Avrami-Erofeev kinetic analysis was utilized to determine kinetic parameters. The results suggested a one-dimensional phase growth, as was expected for a linear polymer. The structure of oligomers was also studied computationally. DFT methods were used for shorter polymers, while longer ones were calculated by Fragment Molecular Orbitals method. Both methods suggest helical E-conformations to be the most stable, with a full helix turn after 38 Å. Lower stability of Z-isomers is explained by electrostatic repulsions between oxygen atoms which are spaced much more closely than in E- isomers. Since FMO method showed good correlation with the DFT results and was much faster, we find it suitable for theoretical study of similar polymers and further investigation.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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