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Int. J. Mol. Sci. 2011, 12(10), 6703-6721; doi:10.3390/ijms12106703

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

1
Laboratorio de Fisicoquıímica Macromolecular, Facultad de Química, Universidad Nacional Autónoma de México, Edificio “D” 108, Ciudad Universitaria, México 04510, D.F., C.P., Mexico
2
Laboratorio 204 de Química Orgánica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, México 04510, D.F., C.P., Mexico
3
Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México 04510, D.F., Mexico
*
Author to whom correspondence should be addressed.
Received: 11 July 2011 / Revised: 22 September 2011 / Accepted: 30 September 2011 / Published: 11 October 2011
(This article belongs to the Section Green Chemistry)
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Abstract

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. View Full-Text
Keywords: kinetic; non thermal microwave effects; activation energy; poly(amic acid) kinetic; non thermal microwave effects; activation energy; poly(amic acid)
This is an open access article distributed under the Creative Commons Attribution License (CC BY 3.0).

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MDPI and ACS Style

Tellez, H.M.; Alquisira, J.P.; Alonso, C.R.; Cortés, J.G.L.; Toledano, C.A. 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. Int. J. Mol. Sci. 2011, 12, 6703-6721.

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