An Energy Efficient Sonochemical Selective Oxidation of Benzyl Alcohols to Benzaldehydes by Using Bio-TSIL Choline Peroxydisulfate

Selective Aerobic Oxidation of Alcohols in Low Melting Mixtures and Water and Use for Telescoped One-Pot Hybrid Reactions

An efficient, selective and sustainable protocol was developed for the CuCl₂/TEMPO/TMEDA‐catalyzed aerobic oxidation of activated alcohols to the corresponding carbonyl compounds using water or the environmentally friendly low melting mixture (LMM) d‐fructose‐urea as the reaction medium. Such oxidation reactions proceed under mild (room temperature or 40 °C) and aerobic conditions, with the carbonyl derivatives isolated in up to 98 % yield and within 4 h reaction time when using the above‐mentioned LMM. The potential application of this methodology is demonstrated by setting up useful telescoped, one‐pot two‐step hybrid transformations for the direct conversion of primary alcohols either into secondary alcohols or into valuable nitroalkenes, by combining oxidation processes with nucleophilic additions promoted by highly polarized organometallic compounds (Grignard and organolithium reagents) or with nitroaldol (Henry) reactions, respectively.

Ionic Liquids: Environment-Friendly Greener Solvents for Organic Synthesis

Constituted by ions, ionic liquids (ILs) are evolving as greener solvents for many organic syntheses. Due to their high solvent power and low volatility, ionic liquids are serving as an environment-friendly substitute to conventional volatile organic solvents. The present review introduces ionic liquids as an insight into the diverse recent applications of ILs in organic synthesis.

Ultrasound-mediated radical cascade reactions: Fast synthesis of functionalized indolines from 2-(((N-aryl)amino)methyl)acrylates

Novel functionalized indolines were synthesized from 2-(((N-aryl)amino)methyl)acrylates and formamides under ultrasonic irradiation for the first time. Aiming to develop a straightforward and easy-to-implement methodology for the synthesis of indolines, an instrumentation setup was designed, including ultrasound (US) equipment (Ultrasonic Horn; tip diameter of 12.7 mm, 20 kHz, maximum power of 400 W), an open reaction flask, and an inexpensive and green catalyst (1 mol%; FeSO4·7H2O; CAS: 7782-63-0) without the need for anhydrous conditions. The use of the sono-Fenton process in the presence of formamides and 2-(((N-aryl)amino)methyl)acrylates afforded a broad range of functionalized indolines within 60 s in high yields. Several experimental parameters of the ultrasound-assisted reaction were evaluated, such as amplitude (40-80%), sonication time (15-60 s), and pulsed ultrasonic irradiation. A 60 s silent reaction did not produce the desired indoline. The optimized conditions for US-mediated reactions allowed the production of functionalized indolines in high isolated yields (up to 99%, 60 s reaction, pulse ration 1 s:1 s, US amplitude 60 %).

Deep eutectic solvents: alternative reaction media for organic oxidation reactions

Deep eutectic solvents (DESs) are a valid alternative to common organic solvents and ionic liquids (ILs) as solvent media for organic oxidation reactions.

Molecular Design and Structure-Property Investigation of n-Dodecylbenzyloxy Ethoxylates

Nonylphenol ethoxylates (NPEO_n) exhibit outstanding application performances, especially in stabilizing silicone oil emulsions, but have been globally banned or use-restricted for serious ecological toxicity. A homologous series of nonionic surfactants, n-dodecylbenzyloxy ethoxylates (DBEO_n), are molecularly designed and synthesized as alternatives to NPEO_n, where the phenolic group of NPEO_n was replaced by a benzyloxy group to counteract the harmful characteristics of NPEO_n, while retaining the benefits. Based on computational studies, we propose a hypothesis that has a conjugation reduction effect (CRE) of DBEO_n relative to NPEO_n on the surfactant structure and properties that solves the biodegradation problem while maintaining the outstanding emulsifying capacity of NPEO_n. A 7-day activated sludge assessment shows that DBEO₈, a representative member of DBEO_n, is almost 100% biodegradable and that the poor biodegradability of NPEO_n may be improved by maintaining the vital benzene ring in DBEO_n molecules, because the oxygen atom of the benzyloxy group is separated from the smaller conjugation system of DBEO_n. Compared to NPEO₁₀, DBEO₈ has a similar cloud point but exhibits higher benzene solubilization and considerably higher emulsion stabilities for mineral oil, biomass oil, and especially silicone oil; this outcome is ascribed to a probable random coil configuration of PEO caused by the CRE of DBEO_n. Therefore, molecular design produces DBEO_n with both excellent biodegradability and outstanding application performances, especially in terms of excellent emulsion stabilities of various oils, as predicted by the CRE hypothesis, thereby serving as an effective alternative to NPEO_n.