Overview[1][2]
Tolidinebesi, also known as o-toluidine and diaminodimethylbiphenyl, is a white to reddish leaf-shaped crystal, soluble in alcohol, ether, and dilute acid, slightly soluble in water, and has an aniline-like odor. Mainly used as dye intermediates. It is also used to produce naphthol AS-G, direct dark green 2B-NB, direct dark brown B-NM, direct yellow-brown ND3G, direct black NBN and various organic pigments. It is obtained by reducing o-nitrotoluene to 2,2′-dimethyl symmetric diphenylhydrazine with zinc powder (or ferrosilicon powder) in sodium hydroxide medium, and then rearranging it.
Apply[2-4]
1. Methods to eliminate the influence of chlorite when testing chlorate in drinking water using the Tolitab method. The detection steps are:
(1) Prepare 1.00g/L chlorate standard solution, weigh 1.276g sodium chlorate and dissolve it in pure water, transfer it to a 1000mL volumetric flask, and adjust the volume to 1000mL with pure water;
(2) Prepare detection reagents. Reagent 1: Weigh 1.35g of tolibexine dihydrochloride, dissolve it in 500mL of pure water, and then add a mixture of 100mL of concentrated hydrochloric acid and mL of pure water; Reagent 2: Take Dissolve 300mL concentrated hydrochloric acid in 700mL distilled water; Reagent 3: Dissolve 650mL concentrated hydrochloric acid in 350mL distilled water;
(3). Draw a standard curve. Take 2 mL of the sodium chlorate standard solution in step (1) and dilute it to 500 mL with pure water. Then take 0 mL, 1 mL, 2 mL, 3 mL, 4 mL, 5 mL, and 6 mL of this solution respectively. , 7mL, 8mL, 9mL, and 10mL were diluted to the mark with pure water in a 50mL colorimetric tube. Take another 11 colorimetric tubes and add 5mL of the above diluted sodium chlorate standard solution into each, and add 0.5mL to prepare in step (2). Shake well the detection reagent 1 and 15mL of reagent 3, use distilled water as a reference, place it at room temperature for 3 minutes and then measure the absorbance at a wavelength of 442nm; and draw a standard curve;;
(4) For the first colorimetric measurement of water samples, take 5 mL of the water sample to be tested, add 0.5 mL of detection reagent 1 and 15 mL of reagent 2 prepared in step (2), shake well, and use distilled water as a reference. After leaving it at room temperature for 3 minutes, measure the absorbance A1 at a wavelength of 442 nm. For the second colorimetric measurement of the water sample, take another 5 mL of the water sample to be tested, add 0.5 mL of detection reagent 1 and 15 mL of reagent 3 prepared in step (2), and shake well. , use distilled water as a reference, place it at room temperature for 3 minutes and then measure the absorbance A2 at a wavelength of 442nm;
(5). According to the two absorbances detected in step (4), the corresponding concentration value is obtained from the standard curve in step (3). After subtraction, the concentration of chlorate in the water sample to be tested is obtained. value.
2. CN201010563355.3 discloses an effective chlorine content measurement test paper, which belongs to the technical field of chemical indicators and is used to detect the concentration of chemical disinfectants, which is beneficial to the concentration monitoring of disinfectant use processes in hospitals and related industries. The analysis filter paper is prepared by soaking in the indicator and then drying. The weight percentage of the indicator ingredients is: 1~3% of tolibex hydrochloride, 35~50% of citric acid, 1~1% of sodium dodecyl sulfonate. 3%, sodium hydroxyethylcellulose 1~2% and the balance water. Among them, the indicator is to add citric acid to water to prepare a citric acid aqueous solution, then add o-toluidine hydrochloride, sodium dodecyl sulfonate and hydroxyethyl cellulose sodium into the citric acid aqueous solution, and stir to completely dissolve it. have to. Easy to use, the results are intuitive and accurate.
3. CN201811475924 discloses a method for determining the sodium chlorate content in sodium hydroxide solution, which belongs to the field of chemical analysis. What the present invention aims to solve is that existing measurement methods cannot draw qualified standard curves and have low accuracy of measurement results. The technical solution is to provide a method for measuring sodium chlorate content in sodium hydroxide solution, which includes the following steps: a. Take a sample of the sodium hydroxide solution and add the chromogenic agent tolibex; b. Add hydrochloric acid dropwise at 0 to 10°C to pH = 6 to 8, then quickly add hydrochloric acid until the hydrogen ion concentration in the solution is ≥ 6 mol/l, quickly Keep the temperature below 20°C during the addition, shake well, let it stand for color development, and measure the absorbance; c. Calculate the sodium chlorate content in the sodium hydroxide solution sample based on the absorbance measurement results. The measurement method provided by the invention can better draw the standard curve, and the measurement results are stable and accurate.
Main reference materials
[1] Concise Dictionary of Fine Chemicals
[2][Invented in China] CN201210138428.3 A method for rapid determination of chlorate in drinking water
[3]CN201010563355.3 Effective chlorine content measurement test paper
[4]CN201811475924.1 Determination method of sodium chlorate content in sodium hydroxide solution
