Accelerated imidization reactions using microwave radiation

Lewis, David A.; Summers, J. D.; Ward, T. C.; McGrath, James E.

doi:10.1002/pola.1992.080300817

Cited by 174 publications

(101 citation statements)

References 4 publications

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“…To our knowledge, only few papers on organic syntheses under MI at low temperature have been reported. Bose et al (1991), Sun et al (1988) and Lewis et al (1992) reported the athermal action of MI on organic synthesis at low temperature. Huang et al (1996a b) studied the kinetics theory of MI on chemistry synthesis at different temperatures.…”

Section: Introductionmentioning

confidence: 99%

Low-temperature synthesis of allyl dimethylamine by selective heating under microwave irradiation used for water treatment

Tian

Zhang

2005

Radiation Physics and Chemistry

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Low-temperature synthesis of allyl dimethylamine (ADA) by selective heating under microwave irradiation (MI) used for water treatment is investigated. The effect of MI, ultrasound irradiation (UI) and conventional heating on yield of ADA, reaction time and the flocculation efficiency of polydiallyl dimethylammunion chloride (PDADMAC) prepared form ADA were studied. The results show that by selective heating at low temperature, MI not only increases yield of ADA and reduces reaction time, but also greatly enhances the flocculation efficiency of PDADMAC. r

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Section: Introductionmentioning

confidence: 99%

Low-temperature synthesis of allyl dimethylamine by selective heating under microwave irradiation used for water treatment

Tian

Zhang

2005

Radiation Physics and Chemistry

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“…entropic effects) are related to the orientation of the reacting molecules to the electric field and consequently facilitate the reaction pathway. These latter "microwave effects" have been a topic of debate where many authors in the mid-90s argued that the presence of an electric field leads to orientation effects of dipolar molecules to influence the pre-exponential factor [69] or activation energy [70] in the rate coefficient. However, we believe that these "special effects"…”

Section: Batch Experiments Using Conventional and Microwave Heatingmentioning

confidence: 99%

Microwave-assisted Cu-catalyzed Ullmann ether synthesis in a continuous-flow milli-plant

Benaskar

Patil

Engels

et al. 2012

Chemical Engineering Journal

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The combination of milli-scale processing and microwave heating has been investigated for the Cu-catalyzed Ullmann etherification in fine-chemical synthesis, providing improved catalytic activity and selective catalyst heating. Wall-coated and fixed-bed milli-reactors were designed and applied in the Cu-catalyzed Ullmann-type C-O coupling of phenol and 4-chloropyridine. In a batch reactor the results show clearly increased yields for the microwave heated process at low microwave powers, whereas high powers and catalyst loadings reduced the benefits of microwave heating. Slightly higher yields were found in the Cu/ZnO wallcoated as compared to the Cu/TiO 2 fixed-bed flow-reactor. The benefit here is that the reaction occurs at the surface of the metal nanoparticles confined within a support film making the nano-copper equally accessible. Catalyst deactivation was mainly caused by Cu oxidation and coke formation; however, at longer process times leaching played a significant role. Catalyst 2 activity could partially be recovered by removal of deposited by-product by means of calcination. After 6 h on-stream the reactor productivities were 28.3 and 55.1 kg prod /(m R 3 •hr)for the fresh Cu/ZnO wall-coated and Cu/TiO 2 fixed-bed reactor, respectively. Comparison of single-and multimode microwaves showed a three-fold yield increase for single-mode microwaves. Control of nanoparticles size and loading allows to avoid high temperatures in a single-mode microwave field and provides a novel solution to a major problem for combining metal catalysis and microwave heating. Catalyst stability appeared to be more important and provided two-fold yield increase for the CuZn/TiO 2 catalyst as compared to the Cu/TiO 2 catalyst due to stabilized copper by preferential oxidation of the zinc. For this catalyst a threefold yield increase was observed in single-mode microwaves which, to the best of our knowledge, led to a not yet reported productivity of 172 kg prod /(m R 3 •hr) for the microwave and flow Ullmann C-O coupling.

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“…Consequently, a faster nucleation rate is expected in this case, reducing the probability of heterogeneous nucleation. In addition, it must be noticed that in the WW assisted heating mode, a dielectric heating of the positive and negative ions and polar molecules of solvent (Lewis et al 1992) takes place, which is originated from the dissipation of energy into heat as an outcome of agitation and intermolecular friction of molecules when dipoles change their mutual orientation at each alternation of the electric field at a very high frequency (Nyutu et al 2008). It has been argued (Zhu et al 2010) that as a consequence of such dielectric heating, after the nucleation stage, most of the precipitating ions are distributed around nuclei well-proportioned, which facilitate the growth of each orientation yielding well crystallized particles.…”

Section: Synthesis and Characterization Of Nanophosphorsmentioning

confidence: 99%

Synthesis and functionalization of biocompatible Tb:CePO4 nanophosphors with spindle-like shape

et al. 2013

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Abstract:Monoclinic Tb:CePO4 nanophosphors with a spindle-like morphology and tailored size have been prepared though a very simple procedure, which consists of aging, at low temperature (120ºC), ethylene glycol solutions containing only cerium and terbium acetylacetonates and phosphoric acid, not requiring the addition of surfactants or capping agents. The influence of the heating mode (conventional convection oven or microwave oven) and the Tb doping level on the luminescent, structural and morphological features of the precipitated nanoparticles have been also analyzed. This study showed that microwave-assisted heating resulted in an important beneficial effect on the luminescent properties of these nanophosphors. Finally, a procedure for the functionalization of the Tb:CePO4 nanoparticles with aspartic-dextran is also reported. The functionalized nanospindles presented negligible toxicity for Verocells and a high colloidal stability when dispersed in water (pH=6.7), which along with theirs excellent luminescent properties, make them suitable for biomedical applications. The functionalized nanospindles presented negligible toxicity for Verocells and a high colloidal stability when dispersed in water (pH=6.7), which along with theirs excellent luminescent properties, make them suitable for biomedical applications. Powered by Editorial Manager® and Preprint Manager® from Aries Systems Corporation

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Accelerated imidization reactions using microwave radiation

Cited by 174 publications

References 4 publications

Low-temperature synthesis of allyl dimethylamine by selective heating under microwave irradiation used for water treatment

Low-temperature synthesis of allyl dimethylamine by selective heating under microwave irradiation used for water treatment

Microwave-assisted Cu-catalyzed Ullmann ether synthesis in a continuous-flow milli-plant

Synthesis and functionalization of biocompatible Tb:CePO4 nanophosphors with spindle-like shape

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