SU1288593A1 - Method of determining high-molecular alkyl-benzol sulphonates and sodium toluene-sulphonates in mixture thereof - Google Patents

Abstract

The invention relates to analytical chemistry, in particular, the quantitative determination of water-soluble high molecular weight alkyl benzene sulphonato B (BS) and toluenesulphonate. sodium (TCH) in sulfonol, detergents and intermediate products, and can be used in chemical and biochemical laboratories x. Improving the selectivity and accuracy of BS and TCH is achieved by analyzing a parallel sample in the presence of another indicator. The determination is carried out by titrating two parallel samples of a substance with a solution of cetylpyridinium chloride in an aqueous chloroform medium in the presence in one case of a mixed indicator — methylene blue and zosin until a pink color of the chloroform layer appears, in the other dimidi bromide and acid blue disulfine until a gray-blue color appears chloroform layer. The contents of BS and TSN are determined by calculation formulas. Analysis time 20 min. The method allows to determine both the sum of the BS and the TSN separately. The relative error is 3%. 1 tab. s (L s: y 00 00 L

Description

1128

This invention relates to analytics. Chemical methods, in particular, methods for the quantitative determination of water-soluble high-molecular-p-1-l alkylbenzenesulfonates (SARS) and sodium toluene sulphonate (TCH) in sulphonol, synthetic detergents (CMC) and intermediate products.

The purpose of the invention is to increase the selectivity and accuracy of the method.

Example 1. A sample of the analyzed product weighing 0.5-0.8 g, taken with an accuracy of not more than 0.0002 g, is placed in a beaker, dissolved in water and transferred to a 250-cm volumetric flask. up to the mark. 10 cm of the test solution is taken into a cylinder with a ground stopper, 0.5 cm of the mixed indicator methylene blue - eosin, 15 cm of chloroform are poured in and the solution is brought to 50 cm of water.

Titrate with a solution of cetylpyridinium chloride (CPH) until the pink color of the chloroform layer (V,) appears.

In another cylinder with a ground-in stopper, 10 cm of the test solution is taken, 5 ml of mixed solution is poured

the indicator of dimidium bromide is disulphine blue, 15 cm of chloroform and the volume of the solution is brought up to 50 cm with water. Titrated with a CPH solution until a blue-gray color of the chloroform layer (V) appears.

The content of high molecular weight alkyl benzene sulphonates X ,,%, is determined by the formula

YI 2,5-M-Mol. M. X, - - - - - -,

where m is the mass of the sample, g;

 the volume of CPC spent for titration with the indicator dimidium bromide - disulfine blue, cm; M is the molarity of the CPH solution,

mol / dm;

Mol. M is the average molecular weight of sodium alkyl benzene sulphonates.

The content of sodium toluensulfonate X,%, is determined by the formula

X

 ,, (V, - Vz) -2 5 “M M, k -,

where m is the mass of the sample, g;

O

59

five

40

45

50

five

32

V. is the volume of CPC spent for titration with methylene blue indicator - eosi-. Mr., cm; M is the molarity of the CPH solution,

mol / dm; , 194 - molecular weight TCH;

K is a proportionality coefficient for TCH, equal to 10. To determine the accuracy of the proposed method, a predetermined amount of TCHO is determined in the analyzed mixture. The results of the experiments are given in the table.

EXAMPLE 2. A weighed sample of an analyzed model mixture containing 20% TCH weighing 1.0214 g is placed in a beaker, dissolved in water and transferred to a 250-cm volumetric flask. Bring the volume of the solution to the mark with water. They are taken into the cylinder with a ground-in stem 10 cm of the test solution, 0.5 cm of the mixed indicator of methylene blue - eosin is poured in,

l

15 cm of chloroform and bring the volume of solution in the cylinder to 50 cm with water.

Titrate with a solution of CPH until the pink color of the chloroform layer appears. Notice the volume of titrant (V, 14.86 cm).

10 cm of the test solution are taken into another cylinder with a ground stopper, 5 cm of the mixed indicator of dimidiumbromide - blue disulfine, 15 cm of chloroform are poured in and the solution is brought to 50 cm with water.

Titrate with a solution of CPC until the appearance of a gray-blue color of the chloroform layer (V 13.84 cm).

The percentage of sodium toluene sulfonate is calculated by the formula

K. (VT- V) -M M, - 250COO „- To: t ToOO -20.10,

where v | - the volume of CPH spent on titration with the indicator methylene blue - eosin, cm;

V is the volume of CPC consumed for titration with the indicator dimidium bromide, disulfin blue, m is the molarity of the solution of CPC,

mol / dm;

M, is the molecular weight of TCH (194); 250 is the volume of the flask taken to dilute the sample, 10 is the volume of solution selected for titration, cm;

1000 - conversion of dm to cm; - coefficient of proportionality;

m is the mass of the sample, g. The coefficient of proportionality is obtained on the basis of the stoichiometry of the mutual action of TCH with the titrating agent in the presence of a Meters blue indicator — eosin.

An example of the calculation of the proportionality coefficient.

By titration of sodium toluene sulfonate containing 97% of the basic substance in the presence of methylene blue eosin indicator, the TCH content is 9.75%, 9.66% and 9.72% (average value 9.71%). Coefficient of proportionality

K 9,99-10.

In the presence of a mixed indicator of dimidium bromide - disulfin, blue TCH is not titrated.

The analysis time does not exceed 20 minutes, the method allows to determine

Dodecylbenzene sulphonate + sodium toluene sulphonate

vniipi

Order 7801/42 Edition 799

Production polygr, pr-tie, Uzhgorod, st. Project, 4

Both the sum of the alkyl benzene sulfonates and the sodium toluene sulfonate separately. The total error is ± 3%.

Claims (1)

Invention Formula The method for determining high molecular weight alkyl benzene sulfonates and sodium luolsulfonate in their mixture by titrating the sample to be analyzed with cetylpyridinium chloride in an aqueous, chloroform medium in the presence of a mixed indicator, dimidiumboremide and acidic disulfine blue, characterized in that, in order to improve the selectivity and accuracy of the method, another sample of the analyte should be used. water-chloroform medium in the presence of a mixed indicator - methylene blue and eosin, followed by determining the components by calculation. 10.00 9.78 Subscription