Comparative Kinetic Study and Microwaves Non-Thermal Effects on the Formation of Poly(amic acid) 4,4′-(Hexafluoroisopropylidene)diphthalic Anhydride (6FDA) and 4,4′-(Hexafluoroisopropylidene)bis(p-phenyleneoxy)dianiline (BAPHF). Reaction Activated by Microwave, Ultrasound and Conventional Heating
| Autor: | José Cortés, Joaquín Palacios Alquisira, Cecilio Alvarez Toledano, Carlos Rius Alonso, Hugo Mendoza Tellez |
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| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
Green chemistry
Condensation polymer Polymers kinetic Activation energy Diamines Catalysis Article Anhydrides Inorganic Chemistry Dioxanes lcsh:Chemistry symbols.namesake chemistry.chemical_compound Sonication Reaction rate constant non thermal microwave effects Diamine Polymer chemistry Spectroscopy Fourier Transform Infrared Benzene Derivatives Physical and Theoretical Chemistry Microwaves Molecular Biology lcsh:QH301-705.5 Spectroscopy Arrhenius equation Chemistry Organic Chemistry Temperature General Medicine poly(amic acid) Computer Science Applications Kinetics Chemical engineering activation energy lcsh:Biology (General) lcsh:QD1-999 symbols Microwave |
| Zdroj: | International Journal of Molecular Sciences, Vol 12, Iss 10, Pp 6703-6721 (2011) International Journal of Molecular Sciences; Volume 12; Issue 10; Pages: 6703-6721 International Journal of Molecular Sciences |
| ISSN: | 1422-0067 |
| Popis: | Green chemistry is the design of chemical processes that reduce or eliminate negative environmental impacts. The use and production of chemicals involve the reduction of waste products, non-toxic components, and improved efficiency. Green chemistry applies innovative scientific solutions in the use of new reagents, catalysts and non-classical modes of activation such as ultrasounds or microwaves. Kinetic behavior and non-thermal effect of poly(amic acid) synthesized from (6FDA) dianhydride and (BAPHF) diamine in a low microwave absorbing p-dioxane solvent at low temperature of 30, 50, 70 °C were studied, under conventional heating (CH), microwave (MW) and ultrasound irradiation (US). Results show that the polycondensation rate decreases (MW > US > CH) and that the increased rates observed with US and MW are due to decreased activation energies of the Arrhenius equation. Rate constant for a chemical process activated by conventional heating declines proportionally as the induction time increases, however, this behavior is not observed under microwave and ultrasound activation. We can say that in addition to the thermal microwave effect, a non-thermal microwave effect is present in the system. |
| Databáze: | OpenAIRE |
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