SU592905A1 - Method of producing reaction paper - Google Patents

Description

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This invention relates to the field of reactive papers for the express semi-quantitative determination of trace amounts of metals.

A known method for producing reactive papers for determining metals by impregnating filter paper with a composition solution consists of a chromogenic reactant complexing agent, a masking agent, a buffering agent, a wetting agent and a fixer 1.

The disadvantage of this method of producing reactive paper is that as a result adsorption fixation of reagents on paper occurs, which does not ensure their firm retention in various modes of contact of reactive paper with the analyzed solution and does not allow to achieve the necessary sensitivity of express determination of metal ions in waste, conditionally clean and natural waters.

In order to impart reactive paper of metal-display, ion-selective and cation-exchange properties, monoaldehyde cellulose-based paper is used as filter paper, and the treatment is carried out sequentially with a 0.1-5% solution of heterylhydrazine or arylhydrazine for 0.1-2 hours and then 0 , 1-5% solution of diazotized arylamine or, respectively, of heterylamine in water and pyridine for 0.1-2 hours.

The resulting reactive paper has metal-displaying, ion-selective and cation-exchange properties with respect to copper ions and makes it possible to quantify copper in wastewater in the concentration range from 0.1 mg / L to 1 mg / L and from 2 mg / L to 500 mg / l

The invention is illustrated by the following examples.

Example 1. Obtaining reactive paper RIB FBTF-6-P based on 1- (5) -phenyl (benzthiazolyl-2) - formazan - (6) - cellulose.

25 g of mono-aldehyde cellulose filter paper are poured with a solution of 0.7 g of 2-benzthiazolyl hydrazine in a mixture of 230 ml of 5% acetic acid and 70 ml of phosphate

the buffer solution with pH 7, is left for an hour, filtered off, filled with water for 5 minutes, filtered, washing with water is repeated twice. Then pour cooled to -1 ° solution obtained with

displacing the diazo compound solution and 3 g of aniline in 100 ml of water and 50 ml of pyridine. After 0.1 hours, filtered, washed twice with water, acetone. The resulting paper is brownish yellow and exhibits

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acid-base properties characteristic of heterylformazans: brightens in a strongly acidic environment, changes to a red-violet color in a strongly alkaline one.

The paper gives a qualitative reaction to formazan: it becomes discolored with bromosuccinimide and restores its original color under the action of an alkaline solution of ascorbic acid. At pH 2.5-5, the paper has a brownish yellow color and forms a colored complex with copper ions of a hypoxic color, with mercury ions of a dark purple color, with silver ions of a purple color. Paper has ion-selective properties. For example, at pH 5, the development of the color of paper by the diodes does not interfere with the action of copper ions 10-fold amounts of lithium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, zinc, cadmium, aluminum, scandium, lanthanum, rare-earth, gallium, indium, tin, titanium, bismuth, chromium, molybdenum, tungsten, uranyl, iron, palladium, lead, rhodium, antimony, cobalt, nickel, niobium, vanadium, platinum, as well as chloride, iodide, sulfate, nitrate, cyan-ion, hypochlorite ion. When the pH is above 7, the paper also forms colored compounds with nickel and zinc ions. Colored paper compounds with metal ions are stable in solutions for at least a month. When washing the paper with 0.25% hydrochloric acid and water, and then drying, the paper is regenerated, restores its original color and can be reused.

Example 2. Getting reactive paper RIB FBTF-6-C. Reactive paper was prepared as in Example 1 with the difference that a 0.1% solution of 2-benzthiazolyl hydrazip was used, 0.7 g per 700 ml; and 0.1% solution of diazo compound, 1 g per liter; and in these solutions stand the paper up to 2 hours

Example 3. Getting reactive paper RIB FBTF-6-C.

Reactive paper was prepared as in Example 1 with the difference that a 5% solution of 2-benzthiazolyl hydrazine, 10 g in 100 ml was used; and 5% solution of diazo compound, 5 g in 100 ml; and the reaction time is reduced to 0.1 hours

Example 4. Reactive paper RIO NBTF-6-C based on 1 (5) - nitrophenyl (benzthiazolyl - 2) - formazan - (6) - cellulose.

Reactive paper was prepared as in Example 1 with the difference that diazotized 4-nitroaniline was used as the diazo compound. The paper has a light brownish-purple color, in a strongly acidic medium at pH 1, light yellow color, in a strongly alkaline medium black color; reacts with copper ions at pH 3-5 with a change in dark green color, with silver and mercury ions - in a dark blue color.

Example 5. Obtaining reactive paper RIB FBBIF-6-C based on 1 (5) - phenyl (benzyl benzimidazolyl) - formazan - (6) cellulose.

The reactive paper is obtained as in Example 1 with the difference that benzyl benzimidozolyl-2-hydrazine is used as the heterylhydrazine. The paper has a brownish-pink color and at pH 5-6 reacts with copper ions with a change to a bright blue color, with ions of nickel, zinc, cobalt, cadmium - to blue, silver and mercury - to lilac. In a strongly acidic environment, the paper acquires a pale greenish color, in a strongly alkaline one - crimson.

Claims (1)

Invention Formula A method of producing reactive paper by treating filter paper with chemical reagents, characterized in that 5, in order to impart metal-indexing, selective and cation-exchange properties, monoaldehyde cellulose-based paper is used as filter paper, and processing is carried out sequentially in 0.1-5% - with a solution of heterylhydrazine or arylhydrazine for 0.1–2 h, and then with a 0.1–5% solution of diazotized arylamine or, respectively, heterylamine in water and pyridine for 0.1–2 h. Sources of information taken into account in the examination 1. US patent number 3843325, cl. 23-230,1974.