Fundamental Studies Of Pharmaceutical Intermediates-benzaldehydes By Indirect Electrooxidation Under Ultrasound

Benzaldehydes are a type of important pharmaceutical intermediates. A new technology of electrosynthesis aromatic aldehyde with non-pollution has attracted increasing attention. Ultrasound acted on chemical reaction has enhanced the reaction rate and increased yield, which has aroused much attention. In this thesis, ultrasonic technique was combined with indirect electrosynthesis to oxidate toluenes to corresponding benzaldehydes. Investigations and results are as follows:Electro-oxidate mechanism of Mn( II) as redox medium on Pb electrode was discussed, and oxidate potential and reduction peak potential were moved negatively under ultrasound. The conditions of electrolysis under ultrasound were optimized on aspects such as current efficiency, oxidate potential, concentration of MnSO₄ and H₂SO₄ Corresponding pharmaceutical intermediates: benzaldehyde, o-methyl--benzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde could be obtained by Mn(III) oxidating toluenes.The yields of three benzaldehydes were found to be increased expect p-methylbenzaldehyde when ultrasound was introduced in the reaction system. And ultrasound's effect on yields of three methylbenzaldehydes was discussed. We also found that no phase-transfer catalyst was needed in the whole process, which made the recycle of the oxidation possible.A potentiometric titration method for determinating benzaldehyde and benzoic acid in electrosynthesis product simultaneously was established, and RSD was less than 2%.As a new generate catalyst, nanoparticles put up excellent catalyze characteristic on aspects of optics and electricity. Nano-Ag and nano-Ag20 have been successfully prepared as well as their catalyze function of electrolysising on Pb electrode were discussed. The yield of Mn(III) was increased by appling their catalyze function in electrolysis process.