SU810075A3 - Method of preparing chlorocyan - Google Patents

Abstract

Cyanogen chloride is made by reacting HCN with hydrogen chloride or hydrochloric acid and H2O2 in aq. medium in the presence of cupric and ferric ions under pressure, and recovering cyanogen chloride on the one hand and O2 and N2 on the other, separately. The cupric ions are pref. present at 0.077 mole/l and the ferric ions at 0.0125-0.025-0.025 moles/l.

Description

(54) METHOD FOR OBTAINING CHLORTSIAN

This invention relates to inorganic chemistry, and specifically to methods for producing cyanogen. The closest to the invention is a method for producing chlorocyan by reacting cyanic water of the genus with hydrogen chloride in the presence of hydrogen peroxide and an aqueous solution of a catalyst containing copper and iron ions at 40-60 ° C in a yield of 90-92% calculated on hydrogen cyanide one. . The disadvantages of the method are the low degree of decomposition of hydrogen peroxide and the oxidative saponification of hydrogen cyanide, which is the reason for the presence of oxygen and carbon dioxide in gaseous chlorine gas up to 5 times the weight of each. The purpose of the invention is to increase the purity and yield of cyan chloride. This goal is achieved by the method of producing chloro cyan by reacting hydrogen cyanide with hydrogen chloride in an aqueous medium at 4O-6 in the presence of hydrogen peroxide and a circulating catalyst solution containing copper and iron ions under a pressure of 1.5-16 bar, preferably 2-4 bar, with the regeneration of the catalyst and the simultaneous removal of the water introduced and formed as a result of the reaction of water, which, together with the catalyst solution, is removed from circulation through the weakly acidic cation exchanger, and the release of chloro cyan is carried out Decompressing the liquid fraction under pressure with a circulating catalyst solution. It turned out that the use of a pressure of 1.5–16 bar, preferably 2–4 bar, does not only slow down the reaction, but facilitates the formation of chlorine cyane, despite the fact that, according to the total formula HCN + HCl + HnOo, ClCN + 2H, 0 -53.5 mol. The opposite phenomenon should be expected, since chlorocyan at a pressure of 1 bar, volatilizes from the reaction solution and thus can affect equilibrium. . When using another solution, chlorine cyan completely dissolves in the reaction solution and therefore is significant. The degree of conversion of hydrogen cyanide increases and, consequently, the yield is increased.

Chlorine cyanide can be directly separated from oxygen, nitrogen, and most carbon dioxide. Due to the large difference in solubility under pressure between chlorocyan and oxygen, due to the slight decomposition of hydrogen peroxide, it is possible in the reaction mixture to select gases that are insoluble in the reaction mixture: oxygen, nitrogen and carbon dioxide, they are freed from pressure under pressure chlorine cyanide and removed.

Thus, by means of decompression, gaseous chloro cyan is obtained, which is almost free from gas impurities, by the reaction solution.

The catalyst solution used, containing copper ions of 0.077 mol / l and iron of 0.0125-0.025 mol / l, is separated and recycled. The water introduced with the components and formed during the reaction is removed from the circulation together with the catalyst solution through the ion exchanger. At the same time, copper and iron ions bind to the ion exchanger, which is exposed to the action of the waste solution. Thanks to this method of water separation, copper and iron ions are regenerated, but ammonium chloride formed in the catalyst solution as a result of the oxidative saponification of hydrogen cyanide accumulates in the circulating solution only to a certain extent as it does not bind to the ionone,

exchanger and discharged with water. As a cation exchanger, a macroporous polystyrene-based ion exchanger, containing weakly acid exchangeable groups, is predominantly used.

After saturation with the catalyst solution, the ion exchanger is washed with a dilute mineral acid, preferably 1-10% HCl, and the catalyst solution then in concentrated form is returned to the circulation.

In the case of the presence of phosphoric acid in the withdrawn solution of the catalyst, the cation exchanger is treated with mineral acid only after pre-treatment with a substance having an alkaline reaction. This is important for the case when phosphoric acid-stabilized liquid hydrogen cyanide is used as the reaction component. When carrying out the process, it is desirable to maintain a pH of 0.1-0.5, preferably 0.25-0.35, at 40 ° C. ° C.

Hydrogen cyanide is used in gaseous or liquid form, hydrogen chloride. In a gaseous or in the form of an aqueous solution 0.5-36 wt.%, Preferably 8-20 wt. ;. Hydrogen peroxide is used preferably in the form of a 30-50% solution. The reaction components should be used in approximately stoichiometric amounts.

Example 1. 1.6 kg / h of hydrogen cyanide are fed to 40 l of the reaction solution containing 13.0 g / l of CuCl ,, - and 3.35 g / l of FeCl. , 34 (301 kg / h) of a 50% hydrogen peroxide solution (10% excess) and 21.6 kg / h of a 10% hydrochloric acid solution are introduced. The pH is maintained between 0.25 and 0.35. A pressure of 4 bar is created, t 50 ° C. The average yield of cyan chloride is 96.2%.

Chlorine cyan contains 0.1–0.3 wt.% Of cyanogen, 0.5 wt.% Of hydrogen cyanide and less than 0.5% of carbon dioxide and nitrogen together. Oxygen is not detected

The waste water and the catalyst solution formed after the distillation are fed into the ion exchanger of the apparatus, where copper and iron ions are retained and washed out with a 10 wt.% Solution of hydrochloric acid.

Example 2. In a 40 liter of a solution containing 13 g / l of CuCl22H20 and b, 7g / l of FeClg-, 1.6 kg / h of liquid hydrogen cyanide stabilized with 0.1% by weight of phosphoric acid, 4.3 kg / h are introduced. 50% aqueous hydrogen peroxide solution and .27 kg of 8% hydrochloric acid. pH 0.25-0.35, t. The amount of outgoing waste water is 30 l. The phosphoric acid bound in the ion exchanger is washed out with 0.5% sodium hydroxide solution, and then copper and iron ions are eluted. The yield of the product is 96%, purity, as in example 1.

Claims (3)

1. A method for producing cyanogen by reacting hydrogen cyanide with hydrogen chloride in an aqueous medium at 40-60 ° C in the presence of hydrogen peroxide and a circulating catalyst solution containing copper (II) and iron (III) ions while regenerating the latter while removing as a result of the water reaction, characterized in that, in order to increase the purity and yield of cyan chloride, the interaction is carried out under pressure followed by release of cyan chloride by decompression of the liquid fraction and washing; ION circulating catalyst solution. 2; A method according to claim 1, characterized in that the process is carried out under a pressure of 1.5-16 bar, preferably 2-4 bar. 3. The method according to Claim 1, characterized in that the water introduced and resulting from the reaction, together with the catalyst solution, is withdrawn from circulation through a weakly oxidized lot cation exchanger. Sources of information taken into account in the examination 1. German patent 1 2131383, 1КЛ. 12 K 3/00, 1973.