TPPS supported on core–shell PMMA nanoparticles: the development of continuous-flow membrane-mediated electrocoagulation as a photocatalyst processing method in aqueous media

Herein, the successful utilization of core shell poly-methyl methacrylate nanoparticles (CS-PMMA NPs) as a valuable support for organocatalyst immobilization in aqueous medium is presented along with an unprecedented direct current-based electrochemical method for processing a water colloid of the r...

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Bibliographic Details
Published in:Green chemistry : an international journal and green chemistry resource : GC 2015-03, Vol.17 (3), p.1907-1917
Main Authors: Dambruoso, Paolo, Ballestri, Marco, Ferroni, Claudia, Guerrini, Andrea, Sotgiu, Giovanna, Varchi, Greta, Massi, Alessandro
Format: Article
Language:English
Subjects:
Catalysts
Constants
Electrocoagulation
Electrolysis
Nanoparticles
Nanostructure
Polymethyl methacrylates
Separation
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Summary:Herein, the successful utilization of core shell poly-methyl methacrylate nanoparticles (CS-PMMA NPs) as a valuable support for organocatalyst immobilization in aqueous medium is presented along with an unprecedented direct current-based electrochemical method for processing a water colloid of the resulting nano-supported catalyst. The NP coagulation procedure relied on various electrocoagulation techniques and it was achieved through water electrolysis occurring in a dialysis membrane immersed in the colloid. Mass recoveries of up to 95% w/w were obtained for the NPs within 1 h of electrolysis. This was optimized at a constant current of 90 mA or a constant potential of 24 V. The disclosed NP separation procedure was effectively exploited in a continuous-flow reaction/separation/recycle sequence involving the tetraphenylporphyrin tetrasulfonate (TPPS) organo-photocatalyst immobilized on CS-PMMA NPs (NP2s). After an optimization study aimed at maximizing the chemical efficiency of the entire synthetic and purification process, the nano-supported catalyst NP2 (0.05 mol%) efficiently promoted the photoexcitation of triplet oxygen to singlet oxygen for the selective and environmentally benign sulfoxidation of a model sulfide in an aqueous medium.
ISSN:1463-9262
1463-9270
DOI:10.1039/c4gc01996b