Surfactant-Assisted Ozonolysis of Alkenes in Water: Mitigation of Frothing Using Coolade as a Low-Foaming Surfactant

Abstract

Aqueous-phase ozonolysis in the atmosphere is an important process during cloud and fog formation. Water in the atmosphere acts as both a reaction medium and a reductant during the ozonolysis. Inspired by the atmospheric aqueous-phase ozonolysis, we herein report the ozonolysis of alkenes in water assisted by surfactants. Several types of surfactants, including anionic, cationic, and nonionic surfactants, were investigated. Although most surfactants enhanced the solubility of alkenes in water, they also generated excessive foaming during the ozone bubbling, which led to the loss of products. Mitigation of the frothing was accomplished by using Coolade as a nonionic and low-foaming surfactant. Coolade-assisted ozonolysis of alkenes in water provided the desired carbonyl products in good yields and comparable to those achieved in organic solvents. During the ozonolysis reaction, water molecules trapped within the polyethylene glycol region of Coolade were proposed to intercept the Criegee intermediate to provide a hydroxy hydroperoxide intermediate. Decomposition of the hydroxy hydroperoxide led to formation of the carbonyl product without the need for a reductant typically required for the conventional ozonolysis using organic solvents. This study presents Coolade as an effective surfactant to improve the solubility of alkenes while mitigating frothing during the ozonolysis in water.

Visible-Light Photocatalytic Aerobic C═C Bond Cleavage of Alkenes to Carbonyls by CsPbBr3 Nanocrystals

“…1 H NMR (400 MHz, CDCl 3 ) δ 7.91−7.76 (m, 4H), 7.57 (dt, J = 43.2, 7.4 Hz, 3H), 7.19 (t, J = 8.6 Hz, 2H); 13 C NMR{ 1 H} (101 MHz, CDCl 3 ) δ 195. 3,166.7,164.2,137.5,132.7,132.6,132.5,129.9,128.4,115.68,. 7b White solid, 39.9 mg (0.2 mmol scale), 92% yield, purified by silica gel flash chromatography (EtOAc/ PE = 1/20).…”

“…Ozonolysis reaction of alkenes, first reported in 1840, is one of the most classic strategies for synthesizing carbonyl products via the cleavage of CC double bonds, which still remains a popular synthetic method due to its advantages of operational simplicity and favorable compatibility to substrate scope . Recently, Padungros and co-workers reported a method that can conduct the ozonolysis of alkenes in water assisted by surfactants, affording the desired carbonyl products in good yields . On the other hand, to develop more alternatives to achieve the oxidation of alkenes, lots of catalytic oxidation strategies based on high-valence metal oxide had been documented in the past few decades .…”

“…2 Recently, Padungros and co-workers reported a method that can conduct the ozonolysis of alkenes in water assisted by surfactants, affording the desired carbonyl products in good yields. 3 On the other hand, to develop more alternatives to achieve the oxidation of alkenes, lots of catalytic oxidation strategies based on highvalence metal oxide had been documented in the past few decades. 4 However, these reactions usually proceed in homogeneous systems that suffer from some shortcomings such as difficulty in recycling the metal oxides, environmental pollution, etc.…”

Simultaneous Harvesting of Multiple Hot Holes via Visible‐Light Excitation of Plasmonic Gold Nanospheres for Selective Oxidative Bond Scission of Olefins to Carbonyls

“…To date, the selectivity in oxidation is typically achieved through the ozonolysis process to oxidatively cleave the C=C bonds [29, 30] . However, the use of ozone is wrought with hazardous handling conditions prone to explosive accidents, requiring the use of specialized equipment such as ozonizer and IceCube TM [31–34] .…”

“…[27,28] To date, the selectivity in oxidation is typically achieved through the ozonolysis process to oxidatively cleave the C=C bonds. [29,30] However, the use of ozone is wrought with hazardous handling conditions prone to explosive accidents, requiring the use of specialized equipment such as ozonizer and IceCube TM . [31][32][33][34] Note that the alternatives to ozone (mCPBA, PhIO/HBF 4 , CrO 2 Cl 2 , RuO 4 , and OsO 4 ) are expensive and/or generate stoichiometric amounts of waste, and thus, are not preferred.…”