Synthesis and identification of nicotinium sulfate (3-(1-methylpyrrolidin-2-yl)pyridine:H2SO4) from tobacco-extracted nicotine: A protic ionic liquid and biocompatible catalyst for selective acetylation of amines

Abstract

The object of this effort is conversion of a toxic alkaloid into a proper acidic ionic liquid catalyst, so nicotinium sulfate (3-(1-methylpyrrolidin-2-yl) pyridine·H2SO4 or NHS) was prepared as a new protic ionic liquid by treatment of sulfuric acid with ethereal phase of nicotine extracted from tobacco waste or leaves. 1H NMR, 13C NMR, FT-IR, and CHN analysis confirm the structure of NHS by proton transfer to both of N-methyl pyrrolidine and pyridine of nicotine as [nicotine-2H]2+SO42− (NHS). While a low loading of NHS catalyzes room temperature acetylation of phenols, alcohols, and amines, acetylation of aminophenol occurs selectively on amine group in the presence of NHS. Despite the facile preparation of NHS from bio-renewable materials, this protic ionic liquid is recyclable and reusable without obvious loss of catalytic activity and structure. The superiority of NHS is due to its acid/base structure during the proton transfer.