it well known the phthalazin-1(2H)one is more stable when is prepared by thermal technique especially in polar solvent but when was allowed to prepare via ultrasonic technique, the authors can isolate pure phthalazin-1-ol why, please answer
Not sure if I understand the question. Since the time of Lavoisier, chemists believe that the composition and properties of a specific compound do not depend of the method of preparation, provided that the material is pure.
Surely you may have different crystalline forms, and the method of isolation and purification might have effect on this. However, the method of synthesis will not make any difference in the chemical composition of a substance.
Thank a lot prof. Khlebnikov to response me. it is well known the ultrasound waves have E =hv that help to afford change in the chemical structure via photochemically allowed irreversible reaction i.e not thermodynamic controlled in the products. microwave and ultrasonic products have differ from conventional thermal methods, have different rule with pericyclic reaction. if i have a mistake in thinking Please verify me
Sameh,
First, we need to clarify few things. Ultrasound waves, microwaves and UV light are very much different kind of waves. While microwaves and UV/Visible light (the latter is used in photochemistry) have the similar nature, the ultrasound is completely different matter. I am sure you can find many sources of information to figure out what is what.
Speaking of microwaves - the commonly accepted point of view nowadays is that the microwave irradiation, which is generated in either a household microwave oven sold in Walmart, or in a lab microwave reactor, only provides heating (both operate at 2,450 MHz frequency); surely, this heating is very quick and efficient, but it is essentially the same thermal energy, just delivered differently. Because of that, some reactions are cleaner compared to the conventional heating.
Sometimes, however, you can hear arguments that the microwave effect is not purely thermal. In these situations people talk about "specific microwave effects" or "non-thermal microwave effects". Feel free to read scientific publications in this area and make your own judgement on this matter.
Photochemistry is a different story - in this case indeed, some reactions proceed differently comparing to thermal activation. Again, it is impossible to give good explanation of photochemical reactions here.
In any case, like I have already said earlier, the final product should be the same regardless of the synthetic method chosen to prepare it.
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