SU40351A1 - The method of producing thiourea - Google Patents

Description

The present invention relates to kiuchenin syrup methods by thiourea by; in each case, 11; cyanamide with hydrogen sulfide.

According to the invention, the sulphurous iron is processed; In the initial calcium-ipaneam, the compounds of iron and the precipitated at the beginning of the process, the hydrogen sulfide is removed, are removed by sedimentation, after which the treatment is continued; treatment of cyanamide with hydrogen sulfide in a weakly acidic medium until complete saturation;

 According to the author, without pre-exposure} 1 1. Thiourea is soon stopped, no, - a review of the continuous supply of hydrogen, due to the chemical equilibrium of a reversible chemical reaction.

Example. 1 kg of calcium cyanamide is treated with a 20% solution of sulfuric acid. The reaction follows the equation CaCN2 +,,

/ NH.,.

For 1 kg of calcium cyanamide, on average, 0.4-0.6 kg of technical sulfuric acid is required. at. 1.84 (paper indicator. Congo). The mass resulting from the above chemical reaction is aspirated and compressed. The precipitate is gypsum mixed with coal and other calcium cyanamide contaminants, and the filtrate is a solution of cyanamide and some gypsum. The resulting filtrate is loaded into SO63)

the court (not metal), equipped with a tight stopper with two glass tubes, of which one reaches almost to the bottom, and the other is lowered by 2-3 cm from the stopper.

The splitting end of the tube, reaching the bottom of the vessel, is connected to a source of hydrogen sulfide; 1a, in which three vessels are connected in series to fully utilize the sulfurous water.

The cyanamide solution is loaded with the indicated vessels (not more than two thirds of the vessel volume), equipped with a thermometer, and the hydrogen sulfide is passed until the cyanamide absorption is stopped, i.e., until the end of the reaction.

Sulfur iron precipitated at the beginning of the passage of hydrogen sulfide is removed by suction ;;, after which the go: the sensation of hydrogen sulfide goes further rather vigorously.

The reaction goes by the equation:

NH.

CNNH.-f H. 8 NH,

authority

cyanamide

The end of the reaction is determined by the drop in temperature to the level of the initial one, since as the HoS is absorbed, the temperature of the solution rises by 5-8 ° or the titre of N.

manganese solution

valv.

From the solution, the thiourea is separated off by evaporation on a water or steam bath. After evaporation of the solution to the original volume, the solution in the hot state is cleaned of gypsum, and after cooling and separating the thiourea crystals, the mother liquor is separated and subjected to this procedure 3-4 times, until the whole is extracted.

The yield of urea from one kilogram of technical product is 220-235 g. The temperature of the obtained product is 180.

The subject of the acquisition.

A method of producing thiourea by the interaction of cyanamide with hydrogen sulfide, characterized in that the sulfur compound of iron that is precipitated at the beginning of the process and contained in the initial calcium cyanamide is removed, after which the treatment of cyanamide with hydrogen sulfide is continued.