SU387964A1 - METHOD OF OBTAINING CHLORAL - Google Patents

Description

one

This invention relates to the IK region of the ray and chloral.

A known method for producing chloral ethyl alcohol with subsequent rectifying by chloral powder and returning the selected high boiling components to chlorination.

The yield of the target product is 90%, containing hydrogen chloride 2-3%.

Insufficiently high yield, as well as the need for additional purification of the obtained product is accompanied by this method.

To eliminate such drawbacks, a method has been proposed whereby raw chloral is subjected to azeotropic drying, preferably in the presence of chloroform, before rectification.

At the same time, the product yield is increased to 98.4-99%, and the content of hydrogen chloride is reduced to 0.23-0.5%. The obtained product, without any further purification, is used to obtain a chloral hydrate that meets the requirements of Gos. Pharmacopoeia X.

Example. Synthetic ethyl alcohol is mixed with the high boiling fraction of the reactivation of dehydrated chloral in the ratio of 7: 1 and fed into the alcohol chlorination system, consisting of two apparatuses — the chlorinator and the forchlororator.

Chlorinator temperature 89-92 ° Temperature of the farchlorator 59-62 ° C. Technical chloral is taken from the gas phase of the chlorinator. The product yield is 4.8% higher than in the chlorination of ethyl alcohol without the addition of a high boiling fraction.

Technical chloral is mixed with chlorophar. The temperature in the cube is maintained within the range of 70-75 ° C, the temperature in pairs - 60-65 ° C.

The azeotrope of water with chloroform is condensed in a refrigerator, enters a settling tank, from where the light aqueous phase is removed for neutralization, and the heavy phase is returned to a cube. A dehydrated mixture of chloral and chloroform is taken from the cube.

The compositions of the initial mixture, distilled aqueous phase, and dehydrated mixture are given in tab. one.

The distillation of the dehydrated mixture was carried out on a laboratory column with an efficiency of 10 mt. The diameter of the column is 20 mm, the height of the nozzle is 54 cm. The head of the column is adapted to trap water distilled from chloroform.

The composition of the initial mixture, distilled water and dehydrated mixture

387Y64

Table 1

 The rest is chloroform. The rest is water.

A mixture of x; 1ral with chloroform continuously falls into the middle of the column at a rate of 150-250 ml1 hour. With a reflux number of 5-7 and temperatures: cube 99-101 °, top 60-64 °;

The composition of chloral t-raw and chloroform after rectification

The rest of the chloral content is chloroform.

The isolation of pure anhydrous chloral is carried out on a conventional laboratory column with an efficiency of 10 tons, 18 mm in diameter, filled with a nozzle to a height of 56 cm.

Chloral is continuously served at 7 tons. at a speed of 200-250 ml1h.

chloroform is taken from above, chloral-1blower is removed from the cube. The quality of chloral powder and distilled xoroform are given in table. 2

table 2

Column operation mode: cube temperature 117-120 °, temperature above 95-97 °, reflux number 3-5. Chlorine and bottom and bottom residues are taken continuously. Selection of chloral from the filed was 87-90%.

Kachetbo chloral and the composition of the cubic residue are given in table. 3

Table 3