SU1054345A1 - Process for preparing stylbaso - Google Patents

Abstract

THE METHOD OF OBTAINING STILBAZO by tetrazotizing diaminostilbendisulfonic acid with sodium nitrite in a hydrochloric acid medium, followed by a combination of tetrazonium salt. with pyrocatechin in ethanol upon cooling and isolation of the target product by treating with ammonium chloride P1ei 90-95 ° C, characterized in that, in order to increase the yield of the target product, the tetrazotization process is carried out in a glass reactor, as well. the combination of tetrazonium salt with pyrocatechin in - when. (-5) - (- 10) p. (Ls

Description

ABOUT

ate

4 with 42 sd The invention relates to an improved method for producing stilbao (stilb 4,4-bis-1-azo-3 ammonium salt, 4-dioxibeneol) -2,2-disulfonic acid), which is used as a reagent for the colorimetric determination of aluminum and, in particular, in the presence of beryllium. A known method for the production of stilbazo by tetraetherization of diaminoyl bendisulfonic acid with sodium nitrite in hydrochloric acid at 3–5 ° C followed by intermediate combination of a tetrazonium salt with pyrocatechin in ethanol at 0–3 ° C and isolation of the desired product after treatment with ammonium chlorite at 90–95 ° G. The yield of the final product is 35-40%. The process is carried out in steel enameled reactors 1. The disadvantage of this method is the low yield of the target product. The purpose of the invention is to increase the yield of the target product. This goal is achieved by the fact that according to the method of producing stilbazo by tetrazotization of diamino stilbendisulfonic acid with nitrite on a hydrochloric acid medium with subsequent combination of tetrazonium salt with pyrocatechin in ethanol under cooling and separation of the target product by treatment with ammonium chloride at 90-95 ° C, the process of tetrazonium is conducted in a glass reactor, and the combination of tetra-zon salt with pyrocatechin in ethanol (-5-I-IO C. Target product yield is 84-85%; Example. Step 1. Preparation of a solution of diaminostilbandi sulf Acids and sodium nitrite. In a 20-liter glass reactor equipped with a vapor filter, a water coil, mechanical stirrer, thermometer and bottom runner, 13.5 liters of water are placed, heated before, and with stirring, 1.5 kg (4 mol) of a diaminostilbyl sulfonic acid is added. , then soda ash until silk reacts to a brilliant yellow piece of paper (about 0.6 kg). The resulting dark red solution is cooled to 20 ° C and 0.6 kg of sodium nitrite is added. After complete dissolution of the latter, the solution is filtered, the filtrate is poured into a separating funnel. Stage 2. Tetrasis diamonds nostytilbendy sulfonic. In a 50-liter glass reactor stabilized by a cooling coil, a mechanical stirrer, a separating dropping funnel, a thermometer and a lower descent / place 2.1 l of concentrated hydrochloric acid and .1.4 l of water, the contents are cooled The funnels were added over a period of 1 hour the resulting solution of diaminostilbendisulfonic acid and sodium nitrite. After adding the entire solution, the mixture is left for 15-20 minutes, the precipitated precipitate is filtered on a suction filter; washed with water and then with ethyl alcohol. Stage 3. Combination of tetrazonium salt with pyrocatechin. 25.2 l of ethanol and 1.4 kg of pyrocatechin are placed in a glass 50-sheet reactor. The mixture is stirred until the latter is completely dissolved, cooled to a temperature of (-5) - (-7) s, the resulting tetrazostilbendisulfonic acid is added, held for 10 minutes and 0.51 kg of sodium bicarbonate powder are added in small portions at the same temperature, left mix at this temperature for 30 minutes and then at room temperature for 12-14 hours. Step 4. Preparation of stilbazo. In a 100-liter glass reactor with a steam coil, a mechanical stirrer, a reflux condenser, a thermometer, and a lower descent, 13.4 liters of distilled water are placed, heated to 90-95 ° C, and the resulting reaction mass is introduced there. After dissolving the mixture, a thin stream of 53.6 liters of a 15% aqueous (bottom of a tipped) ammonium chloride solution prepared in a separate glass reactor with a steam coil, reflux condenser, thermometer and lower descent and heated to 90-95 ° C is added. ; After adding the entire ammonium chloride solution, concentrated hydrochloric acid is added to the reaction mixture until the acidic reaction JHa Congo U-1.2 L). The solution is allowed to cool slowly and then, after settling for 12-16 hours, the precipitate is filtered off on a suction filter, drained, discharged into porcelain bowls and dried at 80-90 ° C to constant weight. Obtain 2.21 kg (85%) of stilbazo seropacin powder. The table shows the technical indicators of stilbazo, obtained by known and proposed methods. .

Stilbaeo no TU

Appearance: dark brown or blackish black powder

Aluminum Sensitivity: Dyeing Colorimetric Scale Solutions in Orange

The residue after calcination. (In the form of sulfates): not more than 1%

Solubility in water: the solution should be clear, slight turbidity or opalescence is allowed.

Heavy metal content: not more than 0.01%

Test with hydrochloric acid: the solution should turn blue and precipitate on standing

Test with copper: the solution should turn blue, when standing, a precipitate falls As can be seen from the Data table, the quality of the product obtained by the proposed method fully complies with

Stilba30 obtained by the proposed method

Grayish black powder (equivalent);

Orange color solutions (complies)

0.8-1.0 (equivalent)

Clear solution (complies)

0,009-0,01 (corresponds)

Blue solution (complies)

Blue solution (compliant) i. technical requirements, which allows the use of the product as a reagent in analytical chemistry.

Claims (1)

METHOD FOR PRODUCING STILBASE by tetrazotating diaminostilbendisulfonic acid with sodium nitrite in a hydrochloric acid medium at 3-5 ° C 'followed by a combination of the tetrazonium salt. with pyrocatechol in ethanol during cooling and isolation of the target product by treatment with ammonium chloride at 9'0-95 ° C, characterized in that, in order to increase the yield of the target product, the tetrazotization process is carried out in a glass reactor, a. combination of tetrazonium’s salt with pyrocatechol in ethanol - at. (-5) - (- 10) ° C. Joint venture Sae SI>