RU2313517C1 - Method for preparing dichloroglyoxime - Google Patents

Abstract

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to an improved method for synthesis of dichloroglyoxime. Method involves dosing concentrated hydrochloric acid and perhydrol simultaneously and proportionally at stirring to glyoxime suspension in the mole ratio glyoxime : hydrochloric acid : hydrogen peroxide = (1.0-2.0):(2.2-2.4):2.4, respectively, in the weight ratio of the total water amount and calcium chloride = (1.2-2.8):1.0 and temperature 15-25⁰C. Method provides preparing the end product with the yield 81-93%.

EFFECT: improved method of synthesis.

1 tbl, 1 ex

Description

The present invention relates to a method for producing chloroglyoximes, starting materials for the preparation of functional derivatives of glyoximes, as well as heterocyclic compounds: triazoles, tetrazoles, 1,2,5-oxadiazoles and their N-oxides [J. All Chem. islands to them. D. I. Mendeleev, 2, 65, (1974)].

A known method of producing dichloroglyoxime (DHG), by chlorination of an aqueous solution of α-glyoximecarboxylic acid [Ponzio. de Paolini, Gazz, Chim. Ital; 56.252 (1926)].

The small yield (about 50%) of DHG, according to the authors, can be explained by the hydrolysis of the initial glyoxime, which accelerates with increasing temperature.

A known method of producing DHG by the interaction of di - N - oxides of dinitrile oxalic acid with hydrogen chloride [Angew. Chim. 75, 10, 450 (1963)].

The disadvantage of this method is to obtain di-N-oxide of dinitrile and the complexity of the work due to its low survivability at ordinary temperature. Despite the good yield of DCH, this method cannot be used for the use of DCH in aggregated amounts.

It is known to obtain DHG by chlorination with chlorine of furoxanecarboxylic acid [Ponzio. de Paolini, Gazz, Chim. Ital; 56, 247-256 (1926)].

. К тому же фуроксанкарбоновая кислота не является доступным продуктом.The disadvantage of this method is the side formation of chloronitroic acid,

. In addition, furoxanecarboxylic acid is not an available product.

It is known to obtain DHG from glyoxime under the action of chlorine in 10% hydrochloric acid upon cooling [Ponzio, F. Baldrocco, Gazz. Chim. Ital, 60, 429 (1930)]. According to the data of Ungnade and Kissenger, the yield of DCH does not exceed 52% [N.E. Ungnade, W. Kissinger, Tetrahedron 19, Supple 1, 143 (1963)].

We have chosen this method as a prototype.

The disadvantages of the prototype are the unsatisfactory yield of DHG associated with the hydrolysis of glyoxime, and the complexity of the hardware design of the process, since the use of chlorine requires the use of pressurized cylinders and the disposal of exhaust gases. The presence of a reaction byproduct of hydrogen chloride is also a disadvantage of the method.

A common feature of the claimed invention with the prototype is the chlorination of glyoxime using hydrochloric acid.

The technical problem is to obtain a high yield of DCH, to simplify the hardware design of the process and to eliminate the by-product of the reaction - hydrogen chloride.

The technical result of the invention is achieved by the fact that concentrated hydrochloric acid and perhydrol are metered into a suspension of glyoxime in a concentrated aqueous solution of calcium chloride simultaneously and proportionally with stirring at a molar ratio of glyoxime, hydrogen chloride and hydrogen peroxide, respectively, 1.0: 2.0 ... 2 , 4: 2.2 ... 2.4, with a weight ratio of water and calcium chloride of 1.2 ... 2.8: 1.0 at a temperature of 15 ... 25 ° C.

To obtain a high yield, a necessary condition is compliance with the weight ratio of the total amount of water introduced into the reaction mass together with all the components and calcium chloride 1.2 ... 2.8: 1.0. An increase in this ratio over 2.8: 1.0 leads to a significant decrease in the yield, regardless of the amount of hydrochloric acid and perhydrol used, and a decrease in this ratio below 1.2: 1.0 results in a difficultly mixed reaction mass due to the precipitation of agglomerates of calcium chloride crystals , six-water, i.e. makes the process non-technological.

According to the data presented, the most acceptable is the use of a commonly available 36% hydrochloric acid and a 30% hydrogen peroxide solution (perhydrol).

The lower limit for hydrogen chloride corresponds to a stoichiometric amount, and the upper one corresponds to a stoichiometric amount with a 20% excess. A further increase in excess is undesirable, since it leads to foaming at the end of the process.

It should be noted that when dosing hydrochloric acid into a suspension of glyoxime in a concentrated solution of calcium chloride and hydrogen peroxide, foaming is observed due to the partial decomposition of hydrogen peroxide, catalyzed by impurities of metals introduced into the solution with calcium chloride. The yield of dichloroglyoxime is reduced.

When mixing reagents, the optimum temperature is in the range from 15 to 25 ° C. At temperatures below 15 ° C, the reaction mass becomes non-technological, and above 25 ° C the yield of DCH is reduced.

The amount of calcium chloride solution used to suspend glyoxime in it can be increased by 1.5 times without a significant change in the yield of DCH (experiment 8). A further increase in the amount of this solution is not economically feasible. The decrease makes the reaction mass viscous and therefore not technologically advanced. In contrast to the prototype, the developed method is described by the following equation:

According to the scheme, all hydrogen chloride completely reacts, which is the advantage of the proposed method.

EXAMPLE

To the suspension 88 parts by weight glyoxime in solution 188 parts by weight calcium chloride in 226 parts by weight water with stirring at the same time and proportionally, maintaining the temperature within 15 ... 25 ° C add a solution of 119 parts by weight calcium chloride in 223 parts by weight 36% hydrochloric acid and a solution of 145 parts by weight calcium chloride in 250 parts by weight 30% hydrogen peroxide. The reaction mass is kept at a temperature of 18 ... 20 ° C for 30 minutes, filtered, the resulting crystals are washed with water until the calcium cation Ca ⁺⁺ (2 × 500 parts by weight) disappears and dried. The yield was 153.9 g (98% of theory). The isolated crystals have a melting point of 206 ° C (with sublimation). The IR spectrum of the substance is identical to that of dichloroglyoxime.

The remaining examples are presented for clarity in the table, which shows the specific weight parameters of the manufacturing process of dichloroglyoxime, carried out in the framework of the claimed invention.

A positive effect of the invention consists in obtaining a high yield of DCH, in the absence of a reaction by-product of hydrogen chloride and in simplifying the hardware design of the process, since the need to work with gas cylinders is eliminated.

The advantage of the method is the fact that the obtained dichloroglyoxime does not require purification.

Examples of the implementation of the claimed image on DHG. Hydrochloric acid - 36% Perhydrol - 30% Glyoxime - 88 parts by weight (1.0 mol) Reagent mixing temperature - 15 ... 25 ° С Exposure temperature - 18 ... 20 ° С Exposure time - 30 minutes p / p Name and amount of component in solutions, in parts by weight Total weight, parts by weight The weight ratio of H ₂ About: CaCl ₂ The molar ratio of glyoxime, hydrogen chloride and hydrogen peroxide Exit, DHG Stock solution Hydrochloric acid Perhydrol CaCl ₂ H ₂ O Weight % CaCl ₂ H ₂ O CaCl ₂ Hcl H ₂ O CaCl ₂ H ₂ O ₂ H ₂ O one. 2. 3. four. 5. 6. 7. 8. 9. 10. eleven. 12. 13. fourteen. fifteen. one. 188 226 - 73 130 - 75 175 188 531 2.8: 1.0 1.0: 2.0: 2.2 127.2 81 2. 188 226 - 73 130 145 75 175 333 531 1.6: 1.0 1.0: 2.0: 2.2 133.4 85 3. 188 226 110 80 143 - 75 175 336 544 1.2: 1.0 1.0: 2.0: 2.2 133.4 85 four. 188 226 119 80 143 145 75 175 452 530 1.2: 1.0 1.0: 2.0: 2.2 153.9 98 5. 188 245 108 73 130 159 82 191 455 566 1.2: 1.0 1.0: 2.0: 2.4 146.0 93 6. 188 226 128 88 156 145 75 175 455 565 1.2: 1.0 1.0: 2.4: 2.2 144.4 92 7 ^* . 188 226 119 80 143 145 75 175 452 530 1.2: 1.0 1.0: 2.2: 2.2 130.3 83 8. 282 339 - 73 130 - 75 175 282 644 2.3: 1.0 1.0: 2.0: 2.2 128.7 82 ^* - the experiment was carried out at a temperature of 25 ± 1 ° C

Claims (1)

A method of producing dichloroglyoxime from glyoxime and hydrochloric acid, characterized in that concentrated hydrochloric acid and perhydrol are metered into a suspension of glyoxime in a concentrated aqueous solution of calcium chloride simultaneously and proportionally with stirring at a molar ratio of glyoxime, hydrogen chloride and hydrogen peroxide, respectively 1.0: 2, 0 - 2.4: 2.2 ... 2.4, with a weight ratio of the total amount of water and calcium chloride 1.2 - 2.8: 1.0 at a temperature of 15 - 25 ° C.