processes as perhaps the biggest advantage. The simplicity of the reaction, whether
the reaction vessel is put directly in the microwave oven or hooked up to a reflux
system, is that the reaction cell is still very simple and it is easy to assemble
the experimental set-up. In almost all his papers Komarnani has pointed out the
energy saving in conducting a microwave reaction. MWH is homogeneous: it
starts from the inside and progresses towards the glass container, while the opposite is true for conventional heating. Temperature and concentration gradients
are avoided in a MW reaction. Whether there is a specific microwave effect, namely
a reaction carried out under microwave radiation leading to a different product,
compared with the same reaction under conventional heating, or not, is not clear.
There are a few well known examples showing results different from those obtained by conventional heating [203–205]. However, more detailed kinetic studies
have established [206–208] that chemical reactions, which are carried out under
MW radiation, are controlled by the same fundamental thermodynamics and kinetics as conventional reactions. The title of [206] is ‘‘Specific activation by MWMyth or Reality’’.
In a MWH process one precursor can be heated at much higher heating rates
and reach a higher temperature than its surroundings. In this respect it is similar
to sonochemistry, where hot spots are formed in the liquid. In the polyol reactions
where the first step was the formation of metallic fine particles, we could see the
solution of ethylene glycol hot points reaching 600–700
C. The difference between
sonochemistry and MWH is that in the latter method there is no direct contact
between the energy source and the solution, while in the sonochemistry the horn
is dipped into the solution.
In MWH a reaction can be conducted at temperatures higher than the boiling
point of the solvent while employing a simple apparatus. According to Mingos
[159], it is possible to increase the temperature of a reaction in common organic
solvents up to 100
C above the conventional boiling point of the solvent.
Acknowledgements
This work could not have been performed without the help of so many good
friends from all around the world. I thank them all without trying to name all of
them. I will name however, my coworkers in my laboratory at Bar-Ilan. I would like
to thank Dr. X. Cao, Dr. Ziyi Zhong, Dr. Y. Zhao, Dr. S. Ramesh, Dr. M. Shafi, Dr.
Arul Dhas, Prof. J. J. Zhu, Dr. Liu Suwen, Dr. R. A. Salkar, Dr. P. Jeevanandam,
Prof. X. Tang, Dr. Yanqin Wang, Prof. W. Huang, Prof. Guansheng Peng, Prof.
Ynigchun Zhu, Dr. R. Vijayakumar, Dr. Rohit Kumar Rana, Dr. Hong-Liang Li, Dr.
Jinping Xiong, Dr. Qiaoling Li, Dr. D. N. Srivastava, Dr. V. Ganesh Kumar, Dr. M.
Sivakumar, Dr. Gentao Zhou, Dr. S. Nikitenko, and Dr. Qiu Longhui, my foreign
postdoctorate, for adapting rapidly to the Israeli system and enthusiastically conducting innovative research. I also thank my Israeli Ph. D. and M. Sc. students, Dr.
Gina Katabi, Dr. Shlomit Wiizel, Dr. Oleg Palchik, Mrs. Tatiana Prozorov, Mr.
Ronnen Polsky, Mr. Menachem Motiei, Mrs. Sigalit Avivi (Levi), Mr. Stanislav
Acknowledgements 163
the reaction vessel is put directly in the microwave oven or hooked up to a reflux
system, is that the reaction cell is still very simple and it is easy to assemble
the experimental set-up. In almost all his papers Komarnani has pointed out the
energy saving in conducting a microwave reaction. MWH is homogeneous: it
starts from the inside and progresses towards the glass container, while the opposite is true for conventional heating. Temperature and concentration gradients
are avoided in a MW reaction. Whether there is a specific microwave effect, namely
a reaction carried out under microwave radiation leading to a different product,
compared with the same reaction under conventional heating, or not, is not clear.
There are a few well known examples showing results different from those obtained by conventional heating [203–205]. However, more detailed kinetic studies
have established [206–208] that chemical reactions, which are carried out under
MW radiation, are controlled by the same fundamental thermodynamics and kinetics as conventional reactions. The title of [206] is ‘‘Specific activation by MWMyth or Reality’’.
In a MWH process one precursor can be heated at much higher heating rates
and reach a higher temperature than its surroundings. In this respect it is similar
to sonochemistry, where hot spots are formed in the liquid. In the polyol reactions
where the first step was the formation of metallic fine particles, we could see the
solution of ethylene glycol hot points reaching 600–700
C. The difference between
sonochemistry and MWH is that in the latter method there is no direct contact
between the energy source and the solution, while in the sonochemistry the horn
is dipped into the solution.
In MWH a reaction can be conducted at temperatures higher than the boiling
point of the solvent while employing a simple apparatus. According to Mingos
[159], it is possible to increase the temperature of a reaction in common organic
solvents up to 100
C above the conventional boiling point of the solvent.
Acknowledgements
This work could not have been performed without the help of so many good
friends from all around the world. I thank them all without trying to name all of
them. I will name however, my coworkers in my laboratory at Bar-Ilan. I would like
to thank Dr. X. Cao, Dr. Ziyi Zhong, Dr. Y. Zhao, Dr. S. Ramesh, Dr. M. Shafi, Dr.
Arul Dhas, Prof. J. J. Zhu, Dr. Liu Suwen, Dr. R. A. Salkar, Dr. P. Jeevanandam,
Prof. X. Tang, Dr. Yanqin Wang, Prof. W. Huang, Prof. Guansheng Peng, Prof.
Ynigchun Zhu, Dr. R. Vijayakumar, Dr. Rohit Kumar Rana, Dr. Hong-Liang Li, Dr.
Jinping Xiong, Dr. Qiaoling Li, Dr. D. N. Srivastava, Dr. V. Ganesh Kumar, Dr. M.
Sivakumar, Dr. Gentao Zhou, Dr. S. Nikitenko, and Dr. Qiu Longhui, my foreign
postdoctorate, for adapting rapidly to the Israeli system and enthusiastically conducting innovative research. I also thank my Israeli Ph. D. and M. Sc. students, Dr.
Gina Katabi, Dr. Shlomit Wiizel, Dr. Oleg Palchik, Mrs. Tatiana Prozorov, Mr.
Ronnen Polsky, Mr. Menachem Motiei, Mrs. Sigalit Avivi (Levi), Mr. Stanislav
Acknowledgements 163