An Efficient Conversion of Alcohols to Alkyl Bromides Using Pyridinium Based Ionic Liquids: A Green Alternative to Appel Reaction

Abstract

Pyridinium based ionic liquids namely 4-alkylpyridinium bromides were prepared and used for the conversion of alcohols to alkyl bromides in the presence of p-toluenesulphonic acid in the absence of volatile organic compounds. This solvent free procedure promises to be a much improved and environmentally benign alternative to the Appel reaction.

Computer-Assisted Design of Environmentally Friendly and Light-Stable Fluorescent Dyes for Textile Applications

“…As shown in Figure 5, the hemciayanine dyes could be prepared by 2 steps; the chemical structures of raw materials, intermediates, and dyes are shown in Figure S1, while the geometry structures of the designed dyes are shown in Figure S2. Z1 (DYE-BD) could be easily synthesized in two steps following the references [15,16,17,18], and the route of the synthesis can serve as an example to illustrate the designed routes. The nitrogen center of pyridine features a basic lone pair of electrons; consequently, pyridine is a strong nucleophile.…”

“…Although the Z1 in Figure 5 has been reported and investigated by researchers [15,16,17,18], the properties of other chemicals could be changed by different substituent groups, and the reactivity of intermediates would be changed as well. Thus, analysis and design of proper synthesis routes are important and necessary.…”

“…However, these dyes may not have good light stability, especially when applying them in textile materials. Taking compound Z1 (Figure 1a,b) as an example, it possesses perfect chemical structural features and great fluorescence properties (Figure 1c), emitting yellow–red fluorescence [15,16,17,18], but the light reflectivity of polyacrylonitrile (PAN) fabric dyed by the compound Z1 decreased greatly when it was exposed to the light for 5 h (see Figure 1d). Thus, it was hardly used in dyeing fabrics.…”

Highly efficient and green approach for the synthesis of spirooxindole derivatives in the presence of novel Brønsted acidic ionic liquids incorporated in UiO‐66 nanocages

“…ILs, as a new class of catalysts or solvents, have recently attracted increasing research attention because of their unique properties such as non‐flammability, non‐volatility, reusability, negligible vapour pressure, high thermal stability and wide liquid range . ILs have found applications in Diels–Alder reactions, alkylation, Michael addition, nitration, esterification, etc .…”

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“…Physical properties of the RTILs are adaptable by judicious selection of the cation and anion [1]. In view of the excellent physicochemical characteristics of the ionic liquids, they have been used in lithium batteries [2], electrode position [3], solar cells [4], and electric double layer capacitors [5], and as solvent, reagent and catalyst in organic synthesis [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Among the ionic liquids, protic acidic ones act as catalysts for a variety of organic transformations [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23].…”