دانلود رایگان مقاله لاتین آروماتیک پلی آنیلین از سایت الزویر
عنوان فارسی مقاله:
هالوژن کاهشی هالیدهای آروماتیک پلی آنیلین / نانوالیاف کامپوزیتی آهن صفر صفحه رن: جنبش شناسی و مکانیزم
عنوان انگلیسی مقاله:
Dehalogenation of aromatic halides by polyaniline/zero-valent iron composite nanofiber: Kinetics and mechanisms
سال انتشار : 2017
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مقدمه انگلیسی مقاله:
1. Introduction
Halogenated organic compounds (HOCs) are mostly ubiquitous non-biodegradable pollutants in the environment [1–3]. A large number of HOCs are extensively used in chemical industry [1–3], and also naturally produced [4,5]. Typically, the majority of pernicious brominated compounds, due to their persistence and flame retardants in nature, are easily contaminated and often bioaccumulated in the food chain [1–3,6,7]. For the remediation of HOCs, it is very important to investigate the effective chemical pro-cess for the reclamation of hazards organic halides to less toxic hydrocarbon compounds, and to diminish the resistant waste in our eco-system. In recent years, a considerable amount of work has been reported for dehalogenation of organic halides e.g. photochemical [8,9], oxidation [10,11], and biological processes [12,13]. Metalcatalyzed reductive dehalogenation is one of the most efficient and well-known alternative method in organic synthesis with various available hydrogen sources. For examples, several methods have been performed with highly expensive, toxic metals (e.g. Ni, Pd, Rh, Ru), as well as environmentally noxious reductants (e.g. Bu3SnH, formate, N2H4, NaBH4, Et3SiH, Zn, H2 gas, etc) [14–26]. Therefore, the development of cost effective, and practical catalytic methods are needed to be explored using cheap, and readily available reductant in combination with less toxic, and less expensive metalcatalysts. Consequently, several research groups have been investigated the dehalogenation methods by employing iron as a catalyst [27–30]. However, iron-catalyzed dehalogenation is still to be a demanding task, owing to the issues of environment concern, as well as cost effectiveness of the catalyst. The use of heterogeneous catalyst has aroused a lots of attention compared to homogeneous catalyst with regard to catalyst stability, handling and recyclability [31,32]. In recent years, nanosize metal catalysts are powerful effective tools in the catalytic organic transformation reactions [33–35]. However, the catalyst incorporated with nanofiber supported matrix enhances excellent recycling efficiency [36]. In the development of sustainable catalyst [37], current research trends have fascinated ample attention to find out alternative ways by using cheap, large-abundant, and non-toxic supported metal catalyst. On that note, iron-based nanomaterials are generally recovered from the reaction mixture through simple magnetic separation [38,39]. It is noteworthy that all these properties of iron based magnetic nanoparticles offer unique advantages over their inorganic salts and complexes [40,41]. Furthermore, PANI/Fe0 or Fe3O4 nanocomposite particles, due to its high surface area, have found potential application in water treatment [42–46], corrosion resistance [47,48], fuel cell [49–51], electronic device manipulation [52,53], sensor [54,55], and fabrication [56]. Recently, Fe-PANI/SiO2 core-shell supported metal nanoparticles have shown their catalytic efficiency and recyclability in organic synthesis [57]. Bhaumik et al. reported that PANI/Fe0 nanofibers could be used for the removal of Cr(VI), As(V) and Congo red (CR) dye [44–46]. The kinetics result followed the pseudo-second-order model whereas isotherm results fitted well with Langmuir model. The following two mechanisms for the removal of As(V) were proposed: (i) the adsorption process and (ii) the substitution of surface bonded OH− ligands produced by the reaction of Fe0 and H2O/O2, whereas both adsorption and reduction mechanisms associated with the removal of Cr(VI). For CR dye removal, the degradation mechanism involved through reductive cleavage of the azo linkage of dye by nano-Fe0[46]. Haspulat et al. [43] disclosed the photocatalytic degradation mechanism for the decolourization of textile dyes using Fe ions doped PANI film, whereas Yue et al. [42] explained that the oxidation degradation process involved for the removal of Rhodamine B. Bhaumik et al. [45] also investigated the adsorption behaviour using PANI nanofibers as a highly effective reusable adsorbent. The kinetic data fitted well with pseudo-second-order and adsorption mechanism involved the ionic interaction between positive charge adsorbents and negative charge dye. However, to the best of our knowledge, no scientific study has been reported on the catalytic reactivity of PANI/Fe0 composite nanofibers material for the dehalogenation of aryl halides in the literature. Hence, iron(0)- catalyzed transformations are still to be established for further applications in catalysis. This interest prompted our search to explore whether iron(0) decorated PANI nanofibers would be a potential recyclable catalyst for reductive dehalogenation of aryl halides. As part of our current efforts aimed at developing the economical metal nanomaterials [45,58], herein, we report these findings for reductive dehalogenation of aromatic halides using PANI/Fe0 composite nanofibers. In this work, PANI/Fe0 composite nanofibers, heterogeneous catalyst, were prepared via reductive deposition of nano-sized Fe0 onto the PANI nanofibers matrix for the dehalogenation of aromatic halides. The catalytic activity was tested on different Fe0 loading catalyst, substrates, time and temperature. The leaching and reusability tests were also conducted to know the feasibility of the catalyst. Finally, a plausible mechanism was established for the catalytic cycle.
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کلمات کلیدی:
Dehalogenation of aromatic halides by polyaniline ... - ResearchGate https://www.researchgate.net/.../308128472_Dehalogenation_of_aromatic_halides_by_p... Apr 10, 2017 - Dehalogenation of aryl halides was demonstrated using polyaniline/zero valent iron composite nanofiber (termed as PANI/Fe⁰⁰) as a cheap, ... [PDF]Reactivity of Aryl Halides for Reductive Dehalogenation in (Sea)water ... www.mdpi.com/1420-3049/20/6/9906/pdf by T Suzuka - 2015 - Cited by 3 - Related articles May 28, 2015 - for the hydrodehalogenation of aryl halides in pure water was Ar–Cl ... meta- and para-positions, provided aniline 3c or phenol 3d in yields of ... Dehalogenation of aromatic halides by polyaniline/zero ... - INFONA https://www.infona.pl/.../bwmeta1.element.elsevier-70d98c54-c432-3c36-a4c4-e3e852f... by S Giri - 2017 - Cited by 1 - Related articles Dehalogenation of aryl halides was demonstrated using polyaniline/zero valent iron composite nanofiber (termed as PANI/Fe 0 ) as a cheap, efficient and ... Sparrho | Dehalogenation of aromatic halides by polyaniline/zero-vale https://www.sparrho.com/.../dehalogenation-of-aromatic-halides-by-polyanilinezero... Sep 20, 2016 - Dehalogenation of aromatic halides by polyaniline/zero-valent iron composite nanofiber: Kinetics and mechanisms. Imported: 06 Oct '16 ... Dehalogenation and Hydrogenation of Aromatic ... - ACS Publications pubs.acs.org/doi/abs/10.1021/om1003072 by ML Buil - 2010 - Cited by 46 - Related articles Sep 2, 2010 - Transfer Hydro-dehalogenation of Organic Halides Catalyzed by ... Polyethylene glycol (PEG) promoted hydrodehalogenation of aryl halides. Dehalogenation and Hydrogenation of Aromatic ... - ACS Publications pubs.acs.org/doi/abs/10.1021/om1003072?src=recsys Sep 2, 2010 - Transfer Hydro-dehalogenation of Organic Halides Catalyzed by ... Dehalogenation of aromatic halides by polyaniline/zero-valent iron ...
