- Preparation method of alkaline parafuchsin
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The invention belongs to the field of preparation of chemical products, and relates to a preparation method of alkaline parafuchsin obtained by carrying out catalytic oxidation of diaminodiphenylmethane and aniline by a catalyst in air, wherein the preparation method comprises the following steps: mixing diaminodiphenylmethane and aniline, then stirring to be dissolved in HCl with the concentration of 30%, adding the catalyst, introducing air while heating, and then carrying out azeotropic distillation to obtain a crude product; grinding the crude product, and stirring to be dissolved with a dilute hydrochloric acid solution; 6-8 hours later, adding diatomite, filtering, taking the filtrate, removing filter residues, neutralizing to the pH of 5 with a NaOH solution, filtering, then taking the filter cake and removing the filtrate, putting the filter cake into boiling water with the pH of 4, dissolving, 10-20 hours later, cooling to room temperature, and crystallizing; and finally, filtering, to obtain a solid product, namely an alkaline parafuchsin crystal. The method is a green production process having the advantages of simple process and high yield, and can be widely used in preparation and production of the alkaline parafuchsin.
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Paragraph 0323 - 0333
(2017/09/23)
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- A series of BiO: XIy/GO photocatalysts: Synthesis, characterization, activity, and mechanism
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A series of bismuth oxyiodide (BiOxIy)-grafted graphene oxide (GO) sheets with different GO contents were synthesized through a simple hydrothermal method. This is the first report where four composites of BiOI/GO, Bi4O5I2/GO, Bi7O9I3/GO, and Bi5O7I/GO have been characterized using X-ray diffraction, transmission electron microscopy, scanning electron microscopy energy-dispersive spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and diffuse reflectance spectroscopy. The assembled BiOxIy/GO composites exhibited excellent photocatalytic activities in the degradation of crystal violet (CV) under visible light irradiation. The order of rate constants was as follows: Bi7O9I3/GO > Bi4O5I2/GO > Bi4O5I2 > Bi7O9I3 > Bi5O7I/GO > BiOI/GO > BiOI > Bi5O7I > GO. The photocatalytic activity of the Bi7O9I3/GO (or Bi4O5I2/GO) composite reached a maximum rate constant of 0.351 (or 0.322) h-1, which was 1.8 (or 1.7) times higher than that of Bi7O9I3 (or Bi4O5I2), 6-7 times higher than that of BiOI/GO, and 119-130 times higher than that of BiOI. The quenching effects of different scavengers and electron paramagnetic resonance demonstrated that the superoxide radical (O2-) played a major role and holes (h+) and hydroxyl radicals (OH) played a minor role as active species in the degradation of crystal violet (CV) and salicylic acid (SA). Possible photodegradation mechanisms are proposed and discussed in this research.
- Chou, Shang-Yi,Chung, Wen-Hsin,Chen, Li-Wen,Dai, Yong-Ming,Lin, Wan-Yu,Lin, Jia-Hao,Chen, Chiing-Chang
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p. 82743 - 82758
(2016/11/01)
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- Equilibrium and Kinetic Studies on the Formation of Triphenylmethanols from Triphenylmethane Dyes
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For five kinds of triphenylmethane dyes, the rate constants of hydration and dehydration reactions, and equilibrium constants in an aqueous solution were measured by a stopped-flow method.An increase in the number of dialkylamino groups caused a decrease in the rates and the equilibrium constants of the hydration, and the more the electron-donating effect of the dialkylamino groups, the slower the hydration rate became.The more protonated quinonoids were easily converted to the corresponding alcohols.On the basis of the equilibrium constants, Malachite Green was ascertained to be the best reagent of the five dyes for ion association with heteropolyacids in an aqueous medium.
- Hagiwara, Takuyuki,Motomizu, Shoji
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p. 390 - 397
(2007/10/02)
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- The structure of Schiff reagent aldehyde adducts and the mechanism of the Schiff reaction as determined by nuclear magnetic resonance spectroscopy
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An nmr study of compounds isolated from the Schiff aldehyde reaction between pararosaniline hydrochloride , sulfur dioxide, and acetaldehyde has demonstrated that these adducts are α-anilinoalkylsulfonic acids.The evidence is incompatible with the other structures most often accepted in the literature, N-phenyl alkylsulfonamides.In combination with nmr spectra obtained from solutions of the Schiff reagent and the Schiff reaction and with literature spectrophotometric data, this result leads to a reasonable proposal for the mechanism of the colour development.The effects of the concentrations of the dye, acetaldehyde, and in particular, sulfur dioxide are explained and suggest that the dominant coloured species is a 2:1 acetaldehyde-dye adduct.The nmr results also reveal a kinetic/thermodynamic competition for acetaldehyde between the aniline of the dye and the aldehyde carbonyl leading to bisulfite addition.The relation of the Schiff test with acetaldehyde and the Feulgen test for aldehydes in biological samples is also discussed.
- Robins, J.H.,Abrams, G.D.,Pincock, J.A.
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p. 339 - 347
(2007/10/02)
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