Nano-TiO2 on Dodecyl-Sulfated Silica: As an Efficient Heterogeneous Lewis Acid–Surfactant-Combined Catalyst (HLASC) for Reaction in Aqueous Media

New types of Lewis acids as water-stable catalysts have been developed. Metal salts such as rare earth metal triflates can be used in carbon_carbon bond-forming reactions in aqueous media. These salts can be recovered after the reactions and reused. Furthermore, Lewis acid_surfactant-combined catalysts, which can be used for reactions in water without using any organic solvents, have been also developed. Finally, Lewis acid catalysis in supercritical carbon dioxide has been successfully performed. These investigations will contribute to development of environmentally friendly Lewis acid catalysis.

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Zirconium Tetrakis(dodecyl Sulfate) [Zr(DS)4] as an Efficient Lewis Acid–Surfactant Combined Catalyst for the Synthesis of Quinoxaline Derivatives in Aqueous Media

Synthetic Communications ◽

10.1080/00397910802406737 ◽

2009 ◽

Vol 39 (4) ◽

pp. 569-579 ◽

Cited By ~ 43

Author(s):

Alireza Hasaninejad ◽

Abdolkarim Zare ◽

Mohammad Ali Zolfigol ◽

Mohsen Shekouhy

Keyword(s):

Lewis Acid ◽

Aqueous Media ◽

Quinoxaline Derivatives ◽

Dodecyl Sulfate

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Finding Nano: Challenges Involved in Monitoring the Presence and Fate of Engineered Titanium Dioxide Nanoparticles in Aquatic Environments

Water ◽

10.3390/w13050734 ◽

2021 ◽

Vol 13 (5) ◽

pp. 734

Author(s):

Simone Heilgeist ◽

Ryo Sekine ◽

Oz Sahin ◽

Rodney A. Stewart

Keyword(s):

Titanium Dioxide ◽

Tio2 Nanoparticles ◽

Inductively Coupled Plasma ◽

Titanium Dioxide Nanoparticles ◽

Aqueous Media ◽

Experimental Studies ◽

Aquatic Environments ◽

Nano Tio2 ◽

Icp Ms ◽

Modelling Studies

In recent years, titanium dioxide (TiO2) has increasingly been used as an inorganic ultraviolet (UV) filter for sun protection. However, nano-TiO2 may also pose risks to the health of humans and the environment. Thus, to adequately assess its potential adverse effects, a comprehensive understanding of the behaviour and fate of TiO2 in different environments is crucial. Advances in analytical and modelling methods continue to improve researchers’ ability to quantify and determine the state of nano-TiO2 in various environments. However, due to the complexity of environmental and nanoparticle factors and their interplay, this remains a challenging and poorly resolved feat. This paper aims to provide a focused summary of key particle and environmental characteristics that influence the behaviour and fate of sunscreen-derived TiO2 in swimming pool water and natural aquatic environments and to review the current state-of-the-art of single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) approaches to detect and characterise TiO2 nanoparticles in aqueous media. Furthermore, it critically analyses the capability of existing fate and transport models to predict environmental TiO2 levels. Four particle and environmental key factors that govern the fate and behaviour of TiO2 in aqueous environments are identified. A comparison of SP-ICP-MS studies reveals that it remains challenging to detect and characterise engineered TiO2 nanoparticles in various matrices and highlights the need for the development of new SP-ICP-MS pre-treatment and analysis approaches. This review shows that modelling studies are an essential addition to experimental studies, but they still lack in spatial and temporal resolution and mostly exclude surface transformation processes. Finally, this study identifies the use of Bayesian Network-based models as an underexplored but promising modelling tool to overcome data uncertainties and incorporates interconnected variables.

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