The Synthesis Of Fluorinated Asymmetric Double Azo Chromotropic Acid Color Reagent And Its Metal Bi (iii) Color Reaction

Asymmetry chromotropic acid arsenazo reagent is one of the good sensitivity and high selectivity organic chromogenic agents in determination of metal ion such as Bi3+, Ce3+, Y3+, Th4+ and so on. The general structure of asymmetry chromotropicacid arsenazo reagent is as follows:Based on the lots of literatures and experiences of predecessor, 13 kind of new asymmetry chromotropic acid arsenazo reagent were designed and synthesized. 2,4-bifluoro nitrobenzene was the raw material of synthesis of asymmetry chromotropic acid bisazo fluoroarsen reagent, By way of ammonia substitution, arsonation, reduction and coupled reactions, bisazo fluoroarsen was synthesized. Bisazo fluoroarsen reacted with different substitutional, anilines to synthesize the target products. Infrared spectrum, elemental analysis, mass spectrum and 'H-nuclear magnetic resonance spectrum were empired to indicate the products and middle products, the results were coincidental with the design. The products were purified with solvent extraction and column chromatography. The color of the reagent solvent was so deep that separating interface was hard to distinguish, the rate of production was low with solvent extraction. Column chromatography can purified the reagent effectively, its rate of production was 50-70%, but adsorption of reagent was serious. The mechanism of reaction was discussed.Six out of thirteen reagents can react obviously with bismuth through the studies of the color reaction between reagent and bismuth. The absorption curves, acid medium and acidity conditions, temperature, reaction time, amount of reagent and the allowable of common interfering ion were defined. The result indicated that the reagents were fine to determined bismuth ion. The molar absoptivity of the color reactions were 0.8-0.9 X 105L. mol.cm-1, the accepted limit of some common ions such as Cd2+, Al3+, Ca2+, Zn2+, Mg2+, NHA Na+, Cr3+, Co2+, Mn2+and so on, reachmg level. But the interference of rare earth metal ions was seriously, that indicated the reagent could also be used to determinated rare earth metal ions. This method has been successfully used to determine trace bismuth in some stomach drugs.DBN-FAsA was a better reagent in determination of bismuth. After purified by column chromatography, the active principle of reagent was 96%. It is a organic hexahydric weak acid. In different acidity, the dissociation degree and the color of reagent solvent were different also. Determined and draw the absorption curve of reagent in varies acidity, and figured out the dissociation constant by Perisic-Janjic method; the complex ratio of the reagent and bismuth was determinated by mole ratio method and continuous variation method; The apparent stability constant of the complex was calculated, the mechanism of dissociation and coordination were discussed.