- Modified azobenzene compound and preparation method and application thereof
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The invention discloses a modified azobenzene compound and a preparation method and application thereof. The modified azobenzene compound is prepared by carrying out esterification reaction on polyhydroxy azobenzene and fatty acid subjected to acylating chlorination treatment. The grafting density of the modified azobenzene compound is high and the energy storage density is higher, the fatty acidester group is located at the symmetric position of azobenzene, the intermolecular force is strong, the quantum yield of light conversion, the half-life period of a high-energy isomer and the height of a converted energy barrier can be improved so that the energy storage performance is easier to regulate and control, and the modified azobenzene compound can be used for long-acting storage of solarenergy and other heat energy.
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Paragraph 0054-0057
(2020/10/20)
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- Conversion of anilines into azobenzenes in acetic acid with perborate and Mo(VI): correlation of reactivities
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Azobenzenes are extensively used to dye textiles and leather and by tuning the substituent in the ring, vivid colours are obtained. Here, we report preparation of a large number of azobenzenes in good yield from commercially available anilines using sodium perborate (SPB) and catalytic amount of Na2MoO4 under mild conditions. Glacial acetic acid is the solvent of choice and the aniline to azobenzene conversion is zero, first and first orders with respect to SPB, Na2MoO4 and aniline, respectively. Based on the kinetic orders, UV–visible spectra and cyclic voltammograms, the conversion mechanism has been suggested. The reaction rates of about 50 anilines at 20–50?°C and their energy and entropy of activation conform to the isokinetic or Exner relationship and compensation effect, respectively. However, the reaction rates, deduced by the so far adopted method, fail to comply with the Hammett correlation. The specific reaction rates of molecular anilines, obtained through a modified calculation, conform to the Hammett relationship. Thus, this work presents a convenient inexpensive non-hazardous method of preparation of a larger number of azobenzenes, and shows the requirement of modification in obtaining the true reaction rates of anilines in acetic acid and the validity of Hammett relationship in the conversion process, indicating operation of a common mechanism.
- Karunakaran,Venkataramanan
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p. 375 - 385
(2019/02/14)
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- Photoinduced isocompounds and devices containing photoinduced isocompounds
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The embodiment of the invention discloses a series of photoinduced isocompounds, a preparation method thereof and devices containing the photoinduced isocompounds. The photoinduced isocompounds are connected with gaps of two-dimensional monolayer graphene
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Paragraph 0222; 0223
(2017/09/01)
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- Photocatalytic reduction of nitroarenes to azo compounds over N-doped TiO2: Relationship between catalysts and chemical reactivity
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This work deals with selective reduction of aromatic nitro compounds to corresponding symmetrical substituted azo compounds using nitrogen-doped TiO2 nanoparticles as photocatalyst in the presence of a catalytic amount of formic acid. Various azo compounds containing additional reducible substituents including halogens, and carboxyl and phenol functions have been synthesized in a single step by use of this catalyst. The conversion was reasonably fast, clean, and high yielding at room temperature. A mechanism of formation for the azo compounds is proposed. The behavior of the N/TiO2 catalyst is of particular interest because this is the first time, as far as we know, that formation of azo compounds has been catalyzed by an N-doped TiO2 photocatalyst. Nitrogen-doped TiO2 was prepared by a simple modified sol-gel process with urea as nitrogen source. The catalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy, and transmission electron microscopy. The chemical nature of N was identified by XPS as N-Ti-O in the anatase TiO2 lattice.
- Wang, Huqun,Yang, Xiaofeng,Xiong, Weifeng,Zhang, Zhimin
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p. 3981 - 3997
(2015/06/08)
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- Size-controllable palladium nanoparticles immobilized on carbon nanospheres for nitroaromatic hydrogenation
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In this paper, monodisperse Pd nanocrystals were immobilized on previously reported carbon nanospheres via in situ adsorption and reduction. In this protocol, no excess reductant and capping reagents were necessary, which made the surface of the as-prepared nanocatalysts very clean. Using sodium tetrachloropalladate(ii) as the metal precursor yielded palladium nanocrystals with a size around 5 nm regardless of the metal loading, while the use of palladium chloride resulted in a size increase to 18.1 nm. Moreover, the additives used during preparation have been proven to be of great importance in controlling the average particle size. It was suggested that the pattern of the adsorbed palladium ions or the surface environment of support was greatly influenced. Strong adsorption of the palladium ions on the carbon spheres led to a decrease in size. The nanocrystals exhibited excellent catalytic activity for transfer hydrogenation under ambient conditions. The conversion was 83.1% to 100% for several nitroaromatics with moderate to excellent selectivity. More importantly, these nanocatalysts are promising for renewable catalysis owing to their sustainable support, green catalyst fabrication and ease of handling.
- Lu, Yong-Ming,Zhu, Hai-Zhou,Li, Wei-Gu,Hu, Bo,Yu, Shu-Hong
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p. 3783 - 3788
(2013/07/19)
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- Mechanism and reactivity in perborate oxidation of anilines in acetic acid
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Perborate but not percarbonate in acetic acid generates peracetic acid on standing and the peracetic acid oxidation of anilines is fast. The oxidation with a fresh solution of perborate in acetic acid is smooth and second order but the specific oxidation rate increases with increasing [perborate]0 or [boric acid]. Perborate on dissolution affords hydrogen peroxide and a borate; the latter assists the former in the oxidation. The oxidation rates of anilines under identical conditions do not conform to any of the linear free energy relationships but the reaction rates of molecular anilines do. Perborate oxidation proceeds via two reaction paths but the overall oxidation rates of molecular anilines conform to structure reactivity relationships; the transition states do not differ significantly. Analysis of the oxidation rates of perborate and percarbonate reveals that while perborate oxidation is faster than percarbonate it is at least as selective as the latter.
- Karunakaran, Chockalingam,Kamalam, Ramasamy
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p. 2011 - 2018
(2007/10/03)
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- Structure-reactivity correlation of anilines in acetic acid
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The oxidation of aniline in glacial acetic acid with percarbonate, a dry carrier of hydrogen peroxide, is a second-order reaction conforming to the isokinetic relationship. The hitherto followed method of correlation of the reaction rates in terms of the structure-reactivity relationships is unsatisfactory and erroneous. But the reaction rates of molecular anilines, obtained for the first time, conform to the structure-reactivity relationships.
- Karunakaran, Chockalingam,Kamalam, Ramasamy
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p. 1118 - 1124
(2007/10/03)
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