Bhasarkar Jaykumar B, Chakma Sankar, Moholkar Vijayanand S
Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
Ultrason Sonochem. 2015 May;24:98-106. doi: 10.1016/j.ultsonch.2014.11.008. Epub 2014 Nov 13.
This paper attempts to discern the physical mechanism of the oxidative desulfurization process simultaneously assisted by ultrasound and phase transfer agent (PTA). With different experimental protocols, an attempt is made to deduce individual beneficial effects of PTA and ultrasound on the oxidative desulfurization system, and also the synergy between the effects of PTA and ultrasound. Effect of PTA is more marked for mechanically stirred system due to mass transfer limitations, while intense emulsification due to ultrasound helps overcome the mass transfer limitations and reduces the extent of enhancement of oxidation by PTA. Despite application of PTA and ultrasound, the intrinsic factors and properties of the reactants such as polarity (and hence partition coefficient) and diffusivity have a crucial effect on the extent of oxidation. The intrinsic reactivity of the oxidant also plays a vital role, as seen from the extent of oxidation achieved with performic acid and peracetic acid. The interfacial transport of oxidant in the form of oxidant-PTA complex reduces the undesired consumption of oxidant by the reducing species formed during transient cavitation in organic medium, which helps effective utilization of oxidant towards desulfurization.
本文旨在探究超声和相转移剂（PTA）协同辅助氧化脱硫过程的物理机制。通过不同的实验方案，试图推断PTA和超声对氧化脱硫体系各自的有益作用，以及PTA和超声作用之间的协同效应。由于传质限制，PTA对机械搅拌体系的影响更为显著，而超声引起的强烈乳化有助于克服传质限制，并降低PTA对氧化增强的程度。尽管使用了PTA和超声，但反应物的固有因素和性质，如极性（以及由此产生的分配系数）和扩散系数，对氧化程度有至关重要的影响。从过甲酸和过氧乙酸实现的氧化程度可以看出，氧化剂的固有反应活性也起着至关重要的作用。氧化剂 - PTA络合物形式的氧化剂界面传输减少了有机介质中瞬态空化过程中形成的还原物种对氧化剂的不必要消耗，这有助于氧化剂有效地用于脱硫。
