Aniline solid-phase extraction

Patsias, J. and E. Papadopoulou-Mourkidou. 2000. Development of an automated on-line solid-phase extraction-high-performance liquid chromatographic method for the analysis of aniline, phenol, caffeine and various selected substituted aniline and phenol compounds in aqueous matrices. J. Chromatogr. A 904 171-188. 

Fluorous thiourea conveniently prepared by isothiocyanate perfluorooctyl aniline was also employed in chemoselective oxidation of the sulfide in the presence of 30% HjOj (Scheme 7.30) [46]. The catalyst could significantly shorten the reaction time and improve the product yield. As expected, the catalyst could be easily recovered by fluorous solid-phase extraction and reused for up to five times without significant loss of catalytic activity. 

Diethyl ether (80 mL) solution of [TipSiCl2]20 (2.95 g, 4.76 mmol) was added to a vigorously stirred emulsion of aniline (1.87 g, 20.1 mmol) and water (10.0 g, 556 mmol) in ether (50 mL) at 0°C within 60 min. The mixture was stirred at 0°C for additional 12 h, then warmed to room temperature and stirred for 1 day. The mixture was washed with saturated aqueous ammonium chloride (50 mL) solution, and then the aqueous phase was extracted three times with ether (50 mL each). The combined organic phase was dried over anhydrous magnesium sulfate, filtered, and evaporated to give a colorless solid. The residue was recrystallized from hexane and dried under reduced pressure to afford [TipSi(OH)2]20 (1.65 g, 64%). 

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