SU1482916A1 - Method of producing cyanuric acid - Google Patents

Abstract

The invention relates to heterocyclic derivatives, in particular the preparation of cyanuric acid as an intermediate in the manufacture of pesticides and bleaching and disinfecting agents. The process is carried out by pyrolysis of urea on the surface of molten tin at 280 ° C. The resulting raw material, containing not less than 55% cyanuric acid, is fed to secondary pyrolysis at 290 ° C, followed by hydrolysis in an aqueous acid medium containing 15-18% HNO ₃ and 0.5-2.0% HCL, at 75-85 ° s. This method improves the working conditions and simplifies the process by reducing the corrosion rate of titanium hydrolyzers by 416 times while improving the rhythm of production. 1 tab.

Description

This invention relates to an improved method for producing cyanuric acid used in the manufacture of pesticides, bleaches and disinfectants.

The purpose of the invention is to reduce the corrosion rate, improve working conditions and simplify the process by hydrolysis of crude cyanuric acid in a mixture of 15-18% nitric acid, 0.5-2.0% hydrochloric acid and 80-84, 5% water at 75-85 C.

The invention is illustrated by the following examples.

Example 1. In the industrial primary pyrolyzer serves 967 kg / h of molten urea and on the surface of the molten tin at 280 ° C get

raw cyanuric acid with the content of the main substance not less than 55% and impurities of urea, biuret, triuret, cyamelide, tin, which is crushed and fed to the secondary pyrolyzer, where due to the pyrolysis of residual urea and intermediate products at 280 ° C crude crude cyanuric acid is formed with the content of the basic substance not less than 73% in a mixture with ameline, amelide (25-27%) and residual tin (0.8%). Next, the obtained crude cyanuric acid is subjected to hydrolysis to obtain a marketable product, for which, in advance, 851 kg / h of nitric acid, 1520 kg / h of chemically purified water are poured into the tank for preparing a mixture of acids through rotameters.

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WITH

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The properties of which are corrected by control analysis to form 15% nitric acid and 0.5% hydrochloric acid in a mixture. The resulting mixture in the amount of 2410 kg is fed to an industrial hydrolyzer mixer, where 602.5 kg / h of crude cyanuric acid is loaded. The resulting mass is fed to the hydrolizer, where at 75-85 ° C, the ratio of reacting phases and hydrolysis time is 4-4.5 h (the duration of hydrolysis in all examples remains constant) 599.5 kg / h of cyanuric acid are obtained ( the amount of crude cyanuric acid and the ratio of reactive components in all examples remain constant) in the form of a suspension, which is further cooled, filtered on a belt filter, washed with tin-water and ammonium with water and served for drying. The yield of cyanuric acid after the hydrolysis process is

ten

/ h J5

4829164

nym analysis. The resulting mixture containing 18% nitric and 0.5% hydrochloric acids is fed to an industrial hydrolyzer mixer, the crude cyanuric acid is loaded and hydrolyzed in a hydrolyzer, as in Example 1.

604.4 kg / h product is obtained in the form of a suspension, which is fed for drying, as in Example 1. The yield of cyanuric acid after the hydrolysis process is 99.6% of the stoichiometric, the content of the basic substance is 99.5%.

The resulting product in its technical characteristics is at the level of similar characteristics of the standard sample (see table).

Example 4. A tank for preparing a mixture of acids through the rotameters poured 851 kg / h of nitric acid, 78 kg / h of hydrochloric acid, 1481 kg / h of purified water and the amount of acids in the mixture was adjusted with a control

20

98.6% of stoichiometric, containing 25 analyzes. The resulting mixture with the content of the main substance of 98.5%. The resulting product in its technical characteristics is at the level of similar characteristics of the standard sample (see table).

Example 2 In a tank for preparing a mixture of acids, 924 kg / h of nitric acid, 39 kg / h of hydrochloric acid, 1447 kg / h of purified water are poured through rotameters, and the amount of acids in the mixture is corrected by control analysis. The resulting mixture with a content of 16.3% nitric acid and 0.5% hydrochloric acid is fed into the industrial mixture;

tel hydrolyzer, load nechische- 49 level of similar characteristics

standard sample (see tables

which cyanuric acid is hydrolyzed in the hydrolyser, as in Example 1. 602.5 kg / h of product are obtained in the form of a suspension, which is fed to

standard sample (see table).

Example 5. In the tank for the preparation of a mixture of acids through the rotameters pour 851 kg / h of nitric acid

drying as in example 1. The yield of cyan is $ 155 kg / h of hydrochloric acid, 1404 kg / h

50

After hydrolysis, it is 99.3% of stoichiometric, the content of the basic substance is 99.0%.

The resulting product in its technical characteristics is at the level of similar characteristics of the standard sample (see table).

Example Z. In a tank for preparing a mixture of acids through rotameters, pour 1021 kg / h of nitric acid, 39 kg / h of hydrochloric acid, 1350 kg / h of chemically purified water and adjust the amount of acids in the mixture control

chemically purified water and adjust the amount of acids in the mixture by control analysis. The resulting mixture containing 15% nitric acid and 2.0% hydrochloric acid is fed into an industrial hydrolyzer mixer, the crude cyanuric acid is loaded and hydrolyzed in a hydrolyzer as in Example 1. 603.2 kg / h of product are obtained in suspension and fed to drying as in example 1. The yield of cyanuric acid after the hydrolysis process is 99.4% of the stoichiometric, the content of the main substance

0

five

Using 15% nitric acid and 1.0% hydrochloric acid, is fed to an industrial hydrolyzer mixer, the crude cyanuric acid is loaded and hydrolyzed in a hydrolyzer, as in Example 1.

600.8 kg / h of the product is obtained in the form of a suspension and is fed for drying as in Example 1. The yield of cyanuric acid after the hydrolysis process is 99.0% of stoichiometric, the content of the basic substance is 98.7%. The resulting product in its specifications is on.

level of similar characteristics

standard sample (see table).

Example 5. In the tank for the preparation of a mixture of acids through the rotameters pour 851 kg / h of nitric acid,

155 kg / h of hydrochloric acid, 1404 kg / h

0

chemically purified water and adjust the amount of acid in the mixture control analysis. The resulting mixture containing 15% nitric acid and 2.0% hydrochloric acid is fed into an industrial hydrolyzer mixer, the crude cyanuric acid is loaded and hydrolyzed in a hydrolyzer as in Example 1. 603.2 kg / h of product are obtained in suspension and fed to drying as in example 1. The yield of cyanuric acid after the hydrolysis process is 99.4% of the stoichiometric, the content of the main substance

5148

99.2% of the population. The resulting product in its technical characteristics is at the level of similar characteristics of the standard sample (see table).

Example 6. In the tank for the preparation of a mixture of acids through the rotameters pour 851-1021 kg / h of nitric acid, 23 kg / h of hydrochloric acid, 1366-1536 kg / h of chemically purified water and adjust the amount of acids in the mixture using a control analysis. The resulting mixture with a content of 15–18% nitric and 0.3% hydrochloric acids is fed into an immersed mixer of the hydrolyser, the crude cyanuric acid is loaded and subjected to hydrolysis in a hydrolyzer, as in Example 1.

602.0 kg / h of the product is obtained in the form of a suspension and is fed for drying as in Example 1. The yield of cyanuric acid after the hydrolysis process is 99.2% of stoichiometric, the content of the basic substance is 99.0%. According to its technical characteristics, the resulting product does not correspond to the specification for the finished product, as in the conditions of the example, the solubility rate of tin slows down, the residual amount of which gets into the finished product and contaminates it (see table).

Example 7. In the tank for the preparation of a mixture of acids, through the rotameters, pour 851–1021 kg / h of nitric acid, 194 kg / h of hydrochloric acid, 1365–1195 kg / h of purified water, and adjust the amount of acids in the mixture by control analysis. The resulting mixture with a content of 15-18% nitric and 2.5% hydrochloric acids is fed to an industrial hydrolyzer mixer, the crude cyanuric acid is loaded and hydrolyzed in a hydrolyzer, as in Example 1.

605.0 kg / h of product in suspension are obtained and fed to drying as in example 1. The yield of cyanuric acid after the hydrolysis process is 99.7% of stoichiometric, the content of the basic substance is 99.6%.

According to its technical characteristics, the resulting product is at the level of similar characteristics of a standard sample, however, the corrosion rate of a hydrolyzer made of titanium sharply increases (see table).

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Example 8. 851-1021 kg / h of nitric acid, 39-155 kg / h of hydrochloric acid, 1520-1234 kg / h of purified water are poured into the tank for the preparation of a mixture of acids through rotameters, and the amounts of acids in the mixture are corrected by control analysis . The resulting mixture containing 15–18% nitric acid, 0.5–2.0% hydrochloric acid is fed to an industrial hydrolyzer mixer, the crude cyanuric acid is loaded and hydrolyzed in a hydrolyzer at 70 ° C, as in Example 1.

595.9 kg / h of the product is obtained in the form of a suspension and is fed for drying as in Example 1. The yield of cyanuric acid after the hydrolysis process is 98.2% of stoichiometric, the content of the basic substance is 98.0%.

The resulting product does not correspond to Specification 6-03-384-75 for the finished product, as this reduces the rate of hydrolysis of intermediate products, amelin and amelide, the residual amount of which enters the finished product and contaminates it (see table).

Example 9. In the tank for the preparation of a mixture of acids through the rotameters pour 851-1021 kg / h of nitric acid, 39-155 kg / h of hydrochloric acid, 1520-1234 kg / h of purified water and adjust the amount of acids in the mixture by control analysis. The resulting mixture with a content of 15-18% nitric acid and 0.5-2.0% hydrochloric acid is fed to an industrial hydrolyzer mixer, the crude cyanuric acid is loaded and hydrolyzed at 90 ° C, as in Example 1.

606.2 kg / h of product are obtained in the form of a suspension and are fed for drying as in Example 1. The yield of cyanuric acid after the hydrolysis process is 99.9% of stoichiometric, the content of the basic substance is 99.8%. According to its technical characteristics, the resulting product is at the level of the analogous characteristics of a standard sample, however, the corrosion rate of equipment sharply increases (see table).

This method allows to reduce the corrosion rate of titanium hydrolyzers by 416 times, as well as to increase the service life of enameled hydrolyzers, to improve working conditions and the rhythm of production.

Claims (1)

Invention Formula The method of obtaining cyanuric acid by cyrolysis of urea on the surface of molten tin, followed by the subsequent continuation of the pyrolysis of urea and intermediate products in the second apparatus and the hydrolysis of the resulting crude cyanuric acid in an aqueous acid medium with an increase of 10 one 2 3 four five b 7 eight 9 azoic 98.5 99.0 99.5 98.7 99.2 99.0 99.6 98.0 99.8 99.0 1.2 0.7 0.4 1.0 0.6 0.8 0.3 1.8 0.1 0.7 0.052 0.015 ABOUT 0.045 ABOUT 0.14 ABOUT 0.12 0.05 0.05 Note. The table shows the average data from 5 experiments characterized by the fact that, in order to reduce the corrosion rate, improve working conditions and simplify the process, a mixture of 15–18% nitric acid, 0.5–2.0% hydrochloric acid is used as the aqueous acid medium. acids and 80-84.5% of water, and the hydrolysis is carried out at 75-85 ° C. 75-85 75-85 75-85 75-85 75-85 75-85 75-85 70 90 02-105 0.05 0.05 0.05 0.06 0.07 0.04 0.12 0.05 0.09 25.0