Ethanol-guided synthesis of (flower-on-leaf)-like aniline oligomers with excellent adsorption properties

Abstract

A novel oligoaniline with hierarchical flower-on-leaf microstructures has been fabricated via the oxidation of aniline in EtOH/water (3 : 7, v/v) mixtures. The as-prepared oligoaniline was characterized using the UV-vis, FTIR, 1 H NMR and MALDI-TOF MS techniques for analyzing the chemical structures.A possible formation mechanism has been proposed to interpret the growth of such hierarchical microstructures, and several inter-molecular interactions were suggested to drive the supermolecular assembly. The effect of the ethanol content in the medium on the morphology of the product was discussed, and the functions of the ethanol in the synthesis were explored. Besides, the adsorption properties of the as-prepared product toward organic dyes (crystal violet etc.) in water, as well as the sorption isotherms and kinetics, have been investigated carefully. The realizable sorption capacity for crystal violet was found to be 181 mg g À1 which was higher than those of most of the sorbent.

Enzymatic oligomerization and polymerization of arylamines: state of the art and perspectives

“…Furthermore, the formation of oxygen-containing products (arylhydroxylamine, nitrosoarene, nitroarene, azoxyarene, amino-phenols, benzoquinones, and oligomers containing such structures) is also possible (Ćirić-Marjanović 2013b; Kříž et al 2011; Surwade et al 2009; Zhou et al 2015). The main product as well as the product distribution after the reaction is completed are very dependent on the reaction conditions: this includes such characteristics like the type of oxidant, the concentration of the oxidant, the concentration of the arylamine, the ratio between the oxidant and the arylamine, the solvent type, the presence of co-solvent, the ratio between the solvent and the co-solvent, and the presence and concentration of reaction-controlling templates (Ćirić-Marjanović 2013b; Rakić et al 2015; Walde and Guo 2011).…”

Efficient adsorption/reduction of aqueous hexavalent chromium using oligoaniline hollow microspheres fabricated by a template‐free method

“…2(a)) presents absorption bands at 275 and 386 nm, indicating that aniline oligomers were formed. 26,31 The absorption at 275 nm could be attributed to the -* transition in aniline, given the presence of a residual monomer in the product, while the band at 386 nm might be due to molecules with a phenazine-like structure. 26 Besides, the weak n-* shoulder at about 525 is also observed in the spectrum, which should correspond to linear oligomers.…”

“…The UV–Vis spectrum (Fig. (a)) presents absorption bands at 275 and 386 nm, indicating that aniline oligomers were formed , . The absorption at 275 nm could be attributed to the π –π* transition in aniline, given the presence of a residual monomer in the product, while the band at 386 nm might be due to molecules with a phenazine‐like structure .…”

“…Though these oligoanilines obtained in higher pH media are non‐conductive, they can be applied in different fields that do not need the conductivity of PANI. It has been reported that aniline oligomers can efficiently adsorb organic dyes and heavy metal ions and also reduce high valent metal ions to their low valence forms …”

“…It has been reported that aniline oligomers can efficiently adsorb organic dyes and heavy metal ions and also reduce high valent metal ions to their low valence forms. [30][31][32][33] Herein we report a facile method to fabricate oligoaniline hollow microspheres in alkaline solution at ambient temperature without using any additives as a template. Moreover, the morphology of oligoanilines can be controlled by adjusting the amount of alkaline solution.…”