CS257236B1 - Process for preparing tertiary butyl hypochlorite - Google Patents

Abstract

The solution concerns the utilization of waste from diaphragm chlorine production, namely the method of preparing tertiary butyl hypochlorite from chlorine and tertiary butyl alcohol in an alkaline environment using aqueous solutions of a mixture of sodium hydroxide and chloride and/or potassium hydroxide and chloride, which are waste from electrolytic diaphragm chlorine production. During the reaction, the alkali metal hydroxide is converted into the corresponding chloride, the aqueous solution of which can be used again for chlorine production.

Description

The invention relates to a process for preparing a tertiary butyl hypochlorite of the formula

CH,

I 3

CH - C - O - Cl (I)

I ch ₃

The tertiary butyl hypochlorite of formula I is used in organic synthesis as a source of hypochlorous acid as a chlorinating agent under radical and electrophilic chlorination conditions and as an oxidizing agent / Anbar M., Ginsburg D .: Org. Reactions 54, 925 (1954).

It is usually prepared by chlorination of a solution of tertiary butyl alcohol in aqueous sodium hydroxide / Org solution. Synth., Coll., Vol. IV, 125) or by electrolysis of an aqueous solution of sodium chloride and tertiary butyl alcohol (Dotson, R.L., Lnych, R.W .: J. Eleotrochpm. Soc. 128,

798 (1981) //. In the first process, relatively expensive sodium hydroxide is used. This drawback removes the process for preparing the tertiary butyl hypochlorite of formula I by chlorination of tertiary butyl alcohol in an aqueous alkaline medium.

It is based on the fact that aqueous solutions of mixtures of alkali metal hydroxides and chlorides, preferably sodium hydroxide and / or sodium chloride and / or potassium chloride and / or potassium chloride, used in the electrolytic difragm production of chlorine, are used as the alkaline medium.

The reaction is carried out by adding chlorine to a solution of the tertiary butyl alcohol in an aqueous solution of a mixture of sodium hydroxide and sodium chloride and / or hydroxide and potassium chloride while cooling the reaction mixture. The tertiary butyl hypochlorite of formula I is precipitated as an oil-yellow layer which, after separation, is washed with aqueous solutions of alkali carbonates or aqueous solutions of a mixture of alkali hydroxides and chlorides of the same composition as those used for tertiary butyl hypochlorite, water and dried with inorganic drying agents such as alkali hydroxides, chloride calcium and the like.

The effect of the process according to the invention is that the alkali metal hydroxide contained together with the corresponding chloride in the waste catholyte from the diaphragm chlorine production is utilized in the preparation of tertiary butyl hypochlorite and is converted into the corresponding chloride in this reaction.

An advantage of the process according to the invention is the possibility of direct use of cathode electrolytes from diaphragm chlorine production for the preparation of tertiary butyl hypochlorite. Conversion of the alkali metal hydroxide to the corresponding chloride that occurs in the reaction yields an aqueous solution of sodium and / or potassium choride which can be reused for the electrolytic production of chlorine. '

The process according to the invention is further described in several exemplary embodiments.

He did

Tertiary butyl alcohol / 76.0 g; 1.025 mol) was dissolved in a solution of 720 containing sodium hydroxide (93.6 g); 2.34 mol), sodium chloride (122 g) and water. Chlorine (72 g) was added to the resulting solution with stirring over a period of hours. The temperature of the reaction mixture was maintained between 12 and 15 ° C by external cooling with ice water. The separated oily layer was separated, washed with aqueous sodium carbonate solution and water, and dried with calcium chloride. 96.0 g (86.2%) of tertiary butyl hypochlorite of formula I were obtained.

Example 2

Tertiary butyl alcohol / 148.24 g; 2.0 mol) was dissolved in a 1200 ml solution containing potassium hydroxide (134.6 g); 2.40 mol), potassium chloride (152.0 g); 1.20 mol / a water. Dp of the resulting solution was charged with chlorine / 150.0 g with stirring; 2.1 mol / hr for 3.5 hours. The temperature of the reaction mixture was maintained between 3 and 11 ° C by external cooling with ice water.

The separated oil-yellow layer was separated, washed with an aqueous solution of a mixture of hydroxide and potassium chloride of the same composition as used for the preparation of tertiary butyl hypochlorite. then water. After drying with calcium chloride, 167.2 g (77%) of tertiary butyl hypochlorite were obtained.

Claims (1)

OBJECT OF THE INVENTION A process for preparing a tertiary butyl hypochlorite of formula CH., I ³ ? ' ^CH 3 C1 by chlorination of a tertiary butyl alcohol in an aqueous-alkaline medium characterized in that aqueous solutions of a mixture of alkali metal hydroxides and chlorides which fall off in the diaphragm electrolytic process for producing chlorine, preferably a mixture of hydroxide and sodium chloride, and / or a mixture of hydroxide and chloride potassium.