SU792121A1 - Agent for extraction separation of phenols - Google Patents

Description

(54) REAGENT FOR EXTRACTION SEPARATION OF PHENOLS

one

This invention relates to reagents for the extraction separation of phenols and can be used in analytical chemistry to quantify very low concentrations of phenol.

Currently, halides or sulfates of alkali metals L1 are used to increase the efficiency of the extraction separation of phenols.

However, the use of these salts does not always allow the analysis of the aqueous solution after the separation of interfering components.

In order to achieve complete separation, a large number of successive extractions must be carried out (pain 3). After such a large number of extracts, the remaining amount of phenols in the aqueous phase often does not allow for photocolorimetric determination with sufficient accuracy without prior concentration.

The value of this invention is to increase the efficiency of extraction separation and simplify the method for determining phenols.

This goal is achieved using alkali metal perchlorates in

10 as a reagent for the separation of phenols.

Alkali metal perchlorates are used in the manufacture of safe explosives and pyrotechnic compositions (2).

The introduction of alkali metal perchlorates into the WODA-benzene system in quantities of 2-4 g-eq / l reduces the distribution coefficients (E) of phenol

20 1.4-3.5 times and increases E of phenol derivatives by 1.5-2.5 times (Table 1).

The distribution coefficients of phenol and some of its derivatives in the water-benzene system (20 ° C)

Table

The use of alkaline perchlorates of these components and the mixture of metals makes it possible to increase the effective solutions by 1.5–3 times,

separation of phenol and its pro-25a from solutions, containing n additionally as compared to the effectiveness of salts, is 3–4 times (Table 2)

Separation factors for phenol and some of its derivatives in water-benzene systems ()

Without reagents

table 2

2.84 4.71

1 1.32

- distribution coefficient

phenol in the system; - distribution coefficient

phenol derivative to tone

same system.

HjoOpeTeHHe was tested in laboratory conditions on model solutions containing phenol and its derivatives. For the preparation of solutions, purified preparations are used, identified for purity by melting temperature and refractive index.

Example 1. Extraction-photometric determination of phenol in an aqueous solution containing 4-methylphenol.

Samples of phenol (0.0471 g), 4-methylphenol (0.0541 g) and sodium perchlorate (489.76 g) were quantitatively transferred into a 1000 ml volumetric flask, dissolved, and the resulting solution was diluted with distilled water to the mark. The prepared solution is analyzed for the content of phenol by extraction-photometric method. To do this, aliquots of the solution (10 ml), acidified to pH 2-3, are shaken with equal volumes of benzene in a special installation for 5 minutes. After separation of the system, 5 ml of an aqueous solution are taken out and 1 ml of a freshly prepared 4-sulfophenyldiazonium solution is added to them. The solutions are mixed and after 5 minutes, 1 ml of 2m of MagSO solution is introduced into them. The optical density of the obtained solutions is measured 30 minutes after their secondary mixing (FEC-56, 5 cm, nm). According to the calibration graph, the concentration of phenol in the equilibrium aqueous phase after extraction. The initial concentration of phenol in the analyzed solution (.) Is calculated by the equation:

. C (E + 1),

where C is the concentration of phenol in the equilibrium aqueous phase after extraction, g / l;

E is the distribution coefficient of phenol in the water-benzene system containing 4 g-eq / l NaClO The following concentrations of phenol in the prepared model solution, g / l are obtained:

0.0435.

0.0469 0.0481 0.0474 0.0433 0.0500 0.0492 0.0471 0.0433 0.0498

Average 0.04691: 0.0019 g / l (n 10; J.0.95).

The absolute mean square-p. . the average cloning of the results obtained was 0.0026 g / l, relative 5.54%. The reproducibility of the results obtained was due to the service error in determining the distribution coefficients (3-5%).

The deviation of the results from the true is within the confidence interval of the average value found.

0 Example 2. Extraction photometric determination of phenol in a synthesized 4-methylphenol preparation.

Sample of the analyzed drug

5 (0.1000 g) and chemically pure lithium perchlorate (21.29 g) are placed in a 100 ml volumetric flask, dissolved in distilled water, acidified to pH 2-3 and diluted

Q solution to the mark with the same water. Samples of the obtained solution with a volume of 10 P1 are shaken twice with equal volumes of benzene for 5 minutes, then 5 ml of the solution of the equilibrium equilibrium aqueous phase are taken, treated with 1 ml of freshly prepared solution of 4-sulfophenyldiazonium, after 5 min 1 ml of 2M solution is added . The solutions are stirred and incubated for 30 minutes. Optical densities of the resulting solutions were measured on FEC-56 at, 5 cm and D 440 nm. According to the calibration graph, the concentration of phenol in the equilibrium aqueous phase after extraction is found. The content of phenol in the sample of the analyzed sample (in%) is calculated by the formula:

. 4- C (E + J). 10 a,% - -,

0

where C is the concentration of phenol in the solution after two extraction, mg / ml; .

E is the distribution coefficient of phenol in a water-benzene system containing 2 g.eq./1 L i C I O ;; q .- sample size of the analyzed sample, g:

„0.024 (1.3 + 1) -10 - 1, /%

The standard error of determination (rel.) Was 6.23% with the number of degrees of freedom. The reproducibility of the analysis results is due to the random error in the determination of the distribution coefficients of the partitioned components.

The reagents offered are more soluble in water, than commonly used sulfate or sodium chloride. Is

their use as additives, solutions with concentrations of phenol on the order of 10 10 mol / l can be analyzed.

Reducing the number of HeoOxcciMiJx and wrinkling extraction simplifies

method of analysis, reduces the duration of the determination and consumption of organic solvent. The limit of phenol determination is reduced by 1-2 times. For example, to almost completely separate phenol and 4-methylphenol (1: 1) in a solution containing 4 GEKv / l ZiC 10, it is enough to carry out a single extraction with benzene. The amount of phenol remaining after separation in the aqueous phase allows to reduce the minimum detectable concentration of phenol.

The use of the proposed reagents allows the use of available inexpensive organic solvents — benzene, carbon tetrachloride, and others.

Claims (2)

1. Tukalo E., Tsarik G. Methods of photometric determination of drugs. Chemical Pharmaceutical Journal, 1970, 2 p. 56. 2. Nekrasov B.V. Fundamentals of total 5 chemistry, M., Himi, 1973, vol. 1. with. 263.