Effect of ultrasound in the free radical polymerization of acrylonitrile under a new multi-site phase-transfer catalyst – A kinetic study

Selvaraj, Varathan; Sakthivel, P.; Rajendran, V.

doi:10.1016/j.ultsonch.2014.05.002

Cited by 14 publications

(7 citation statements)

References 39 publications

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“…Conventional PTCP suffers from the low efficiency and yield. In recent years, a series of PTCP assisted by ultrasound irradiation have been investigated by Rajendran’s and Umapathy’s groups, including GMA, EMA, NVI, AN, and MMA systems. − The increase in polymerization rate was observed with ultrasonication applied in all cases. Interestingly, a general rate equation has been derived as summaried in Table .…”

Section: Ultrasound-regulated Systemsmentioning

confidence: 99%

Role of External Field in Polymerization: Mechanism and Kinetics

et al. 2020

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The past decades have witnessed an increasing interest in developing advanced polymerization techniques subjected to external fields. Various physical modulations, such as temperature, light, electricity, magnetic field, ultrasound, and microwave irradiation, are noninvasive means, having superb but distinct abilities to regulate polymerizations in terms of process intensification and spatial and temporal controls. Gas as an emerging regulator plays a distinctive role in controlling polymerization and resembles a physical regulator in some cases. This review provides a systematic overview of seven types of external-field-regulated polymerizations, ranging from chain-growth to step-growth polymerization. A detailed account of the relevant mechanism and kinetics is provided to better understand the role of each external field in polymerization. In addition, given the crucial role of modeling and simulation in mechanisms and kinetics investigation, an overview of model construction and typical numerical methods used in this field as well as highlights of the interaction between experiment and simulation toward kinetics in the existing systems are given. At the end, limitations and future perspectives for this field are critically discussed. This state-of-the-art research progress not only provides the fundamental principles underlying external-field-regulated polymerizations but also stimulates new development of advanced polymerization methods.

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Section: Ultrasound-regulated Systemsmentioning

confidence: 99%

Role of External Field in Polymerization: Mechanism and Kinetics

et al. 2020

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“…[61] In others tudies, under low frequency ultrasound, it has often been observed that the addition of ar adical initiator is essential for polymerization, [19,[62][63][64] indicating that the chemical effects of cavitation are minimal under these conditions. However,s onochemical polymerizations of monomer-in-watere mulsions have been conducted by Biggs [65][66][67] and colleagues in the absence of an added initiator,r esulting in the formationo fu niform latex particles with conversion values dependent on the irradiating intensity.O thers have investigated the (mini)emulsion polymerization of methyl methacrylate (MMA), [68,69] n-butyla crylate (nBA), [58] n-butyl methacrylate (nBMA), [70,71] ethyl methacrylate (EMA), [72] glycidyl methacrylate( GMA), [73] 2-ethylhexyl methacrylate (EHMA), [74] and acrylonitrile (AN), [75 ] among others. [76] The emulsion polymerization of nBA in water was investigated by Xia et al,w here it was observed that in the absence of an added surfactant( e.g.,s odium dodecylsulfate (SDS)), the polymerization wase xtremely sluggish (2.4 %c onversion after 20 min vs.9 1.9 %c onversion in the presence of SDS).…”

Section: Free Radical Polymerizationmentioning

confidence: 99%

Ultrasound and Sonochemistry for Radical Polymerization: Sound Synthesis

McKenzie

Karimi

Ashokkumar

et al. 2019

Chemistry A European J

154

100

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The use of ultrasound as an external stimulus for promoting polymerization reactions has received increasing attention in recent years. In this Review article, the fundamental processes that can lead to either the homolytic cleavage of polymer chains, or the sonolysis of solvent (or other) small molecules, under the application of ultrasound are described. These reactions promote the production of reactive radicals, which can be utilized in chain‐growth radical polymerizations under the right conditions. A full historical overview of the development of ultrasound‐assisted radical polymerization is provided, with special attention given to the recently described systems that are “controlled” by methods of reversible (radical) deactivation. Perspectives are shared on what challenges still remain in polymer sonochemistry, as well as new areas that are yet to be explored.

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“…In fact, because the formation of hydroxyl radical and cavitations bubbles begin to operate in very short time, hence with increasing exposure time, the reduction efficiency will increase slightly (Selvaraj et al 2015 ), in another word the majority of these hormones are removed in early times. Also, the statistical analysis of one-way ANOVA showed there is no significant difference between E1 and E2 concentrations in reactor influent and effluent at different exposure times (P value for E1 and E2 are 0.17 and 0.21, respectively).…”

Section: Discussionmentioning

confidence: 99%

Hormones removal from municipal wastewater using ultrasound

Roudbari

Rezakazemi

2018

AMB Expr

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Estrogens are one of the micro-pollutants in the wastewater which have detrimental effects on water living organisms. The aim of this study was to evaluate the efficiency of ultrasound to reduce the estrogen (E1) and 17 beta-estradiol (E2) from municipal wastewater. Hence, a cylindrical batch reactor was designed. The effects of powers, frequency, exposure time and pH on reduction efficiency were investigated. The residual concentration of E1 and E2 hormones was measured in reactor effluent by electrochemiluminescence (ECL) method. The results showed that ultrasound removed 85–96% of both E1 and E2 hormones after 45 min while other parameters changes in the range of their operations. Also, the frequency and power of ultrasound had a significant effect on reduction efficiency of hormones while the exposure had no significant effect. Furthermore, the interaction of power and frequency reduced their efficacy to 64.3% (Pvalue = 0.005). The result also indicated that the ultrasound waves have high ability to reduce Steroid hormones from municipal wastewater. The proposed method can be considered as one of the significant strategies for reduction or destruction of hormones from wastewater due to the non-generation of dangerous by-products and the low energy consumption.

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Effect of ultrasound in the free radical polymerization of acrylonitrile under a new multi-site phase-transfer catalyst – A kinetic study

Cited by 14 publications

References 39 publications

Role of External Field in Polymerization: Mechanism and Kinetics

Role of External Field in Polymerization: Mechanism and Kinetics

Ultrasound and Sonochemistry for Radical Polymerization: Sound Synthesis

Hormones removal from municipal wastewater using ultrasound

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