SU535295A1 - Method for producing acyl-carboxyalkanoyl peroxides - Google Patents

Description

one

The invention relates to the production of aliphatic diacyl peroxides, specifically the acylcarboxyalkyl, peroxide, of the general formula

R-C (O) 00 (O) C-R-C (O) OH,

where R is an aliphatic radical containing 1-17 carbon atoms,

R is an aliphatic radical containing 2-4 carbon atoms.

Peroxides of this type are used as initiators of various chain radical reactions, including radical polymerization of unsaturated compounds, and also as a semi-product for the synthesis of new classes of peroxides.

A known method for producing acylcarboxyalkanoyl peroxides by acylation of hydrogen peroxide with cyclic dibasic acid anhydrides followed by hydrolysis or perhydrolysis of the resulting product to the peracid and acylation with monocarboxylic anhydride. The first two stages are carried out at room temperature in an aqueous medium. The last stage is carried out at 40-50 ° C in a solvent - carbon tetrachloride, at 40-50 ° C in the presence of a catalyst - sulfuric acid. Yield 40-70% 1.

The main disadvantage of this method is the multi-stage, which is determined by the presence of two additional and difficult stages to obtain polyfunctional acid. The latter, when acylated with monocarboxylic acid anhydride, gives the desired product. It should also be noted that this peracid is unstable during storage, it is easily hydrolyzed or melted, which causes additional difficulties in carrying out the synthesis — the need to obtain it immediately before carrying out the reaction. In order to simplify the process, they propose

A method for producing acylcarboxyalkioalkyl peroxides, the distinguishing feature of which is that the acylation is carried out directly with a mixture of anhydrides in equimolecular ratios at 30-40 ° C in anhydrous

a polar organic solvent in the presence of an acid catalyst, for example, l-toluenesulfonic acid. Isolation of acylcarboxyalkanoyl peroxide is performed by recrystallization of the obtained product from

hexane after preliminary removal of the solvent and the monocarboxylic acid in vacuo.

In the IR spectra of solutions of the obtained compounds IB ecu (thin layer, prisms of NaCl,

X-14, IKS-22 spectrophotometer) the following absorption bands were found: 840 cm, 3000 OHM, 1710 cm-, which are assigned respectively to the groups (-OO-), -C (O) OH ...

BUT (0) C-, -C (O) - Thin-layer chromatography of the separated peroxides is carried out on plates with a fixed silica layer of the mark Silufol.

Eluents benzene: ethanol: acetic acid 114: 6: 1. and benzene: sulfuric ether: ethanol :: g 12,5: 2,12: 1.

The spots of the substances are developed by spraying the plates with 75% aqueous H2SO4 solution and then calcining them at 200 ° C. In all cases, one spot is found, i.e. the isolated peroxides have no impurities.

The advantage of the developed method is cpa (vneniyu with the known is the ease of the reaction and the availability of all used reagents. The synthesis is based on the use of hydrogen peroxide, which eliminates the need for intermediate peroxide compounds.

The synthesis is carried out in one stage, which allows reducing the working time for obtaining the pellet product and the amount of solvent. The energy consumption for moving the solvent, its evaporation, etc., is also reduced. In addition, according to this method, it is not necessary to exempt from the dicarboxylic acid, which is obtained at the hydrolysis stage in the known method.

The yield of the target product in the one-stage process is 60-80% due to the absence of losses at each of the three stages of the known method.

Example 1. Synthesis of a. Acetyl-p- (carboxy) propionyl peroxide

СНзС (О) ОО (О) С (СН2) 2С (О) ОН.

In a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser and a funnel for loose bodies, dehydrated adonitrile (30 ml) and urea peroxide (25 g) are charged. The temperature of the reaction medium is maintained in a water bath in the range of 20–25 ° C. Extraction of hydrogen peroxide is carried out in portions of acetonitrile in 20 ml 5 times for 60-70 minutes. Urea is separated by filtration.

An equimolar mixture of acetic anhydride (10.2 g; 0.1 mol) and succinic anhydride (lOfl g; 0.1 mol) are added to the 7% solution of hydrogen peroxide (0.2 mol) in acetonitrile thus obtained. one drop of concentrated sulfuric acid. The temperature of the medium in the flask is raised to 40 ° C. Stirring is continued for 4.5 hours. Then the flask is cooled. The solution is concentrated, the acetonitrile is distilled under vacuum. The residue is dissolved in ether, washed with water, dried over anhydrous sodium sulphate, then in a vacuum oven and recrystallized from carbon tetrachloride.

The melting temperature of the product is 28.9 ° C, which corresponds to literature data. The content of the main substance in the product according to iodometric analysis for peracils is 98%. The molecular weight is titrimetrically 176.2 (theoretical 176.0). Found %: C 38.75; And 4.30. SatN

Calculated,%: C 38.80; H 4.30. Yield 70%. The IR spectrum of the substance and thin layer chromatography (TLC) data, together with the data obtained above, give reason to believe that the isolated compound is acetyl- | 3- (carbox) -propionyl peroxide. Example 2. Synthesis of capronyl- | 3- (carboxy) propionyl peroxide

CH3 (CH2) 4C (O) 00 (0) with (CH2) 2C (O) OH

In a four-necked flask equipped with a thermometer, a stirrer and a reflux condenser, a 10% solution (170 g) of hydrogen peroxide (0.5 mol) in acetonitrile is prepared, prepared by diluting 98% hydrogen peroxide with acetonitrile, or by extracting hydrogen peroxide from urea peroxide according to the procedure described in example 1 (in the latter case, hydrogen peroxide solutions are concentrated to the desired concentration by evaporation of acetonitrile in a vacuum), and an equimolar mixture of capron anhydride (23.0 g; 0.1 mol) and succinic anhydride (10.0 g; 0.1 mo or) The catalyst for the process is KU-2 ion exchange resin in the H form (1.5 g). Medium temperature 40 ° С.

The reaction time is 5 hours. At the end of the reaction, the contents of the flask are cooled, the ion-exchange resin is separated by filtration, most of the acetonitrile is removed in vacuum, the mixture is diluted with ether, and washed

water over sodium anhydrous sulphate. Then most of the ether is removed, hexane is added until the solution becomes very cloudy and the solution is cooled to -50 ° C for 3 hours. The peroxide crystals are 96% pure (according to iodometric analysis). Melting point 24.6 ° C. Yield 60%. The molecular weight is titrimetric 222.0 (theoretical 220.0). Found,%: C 49.10; H 7.25.

CgHieOe.

Calculated,%: C 49.20; H 7.27. All these data, along with the IR spectrum and TLC, confirm that the isolated compound is capronyl-p- (carboxy) -propionyl peroxide.

Example 3. Synthesis of acetyl-4- (carboxy) -butyryl peroxide

СНзС (О) ОО (О) С (СН2) оС (О) ОН. 113 g (0.5 mol) of a 15% solution of hydrogen peroxide in acetonitrile and an equimolar mixture of acetic anhydride (10.2 g; 0.1 mol) and glutaric anhydride

Claims (1)

(11.41 g; 0.1 mol). Catalyst para-toluenesulfonic acid (0.172 g; 0.001 mol). Further, all operations are carried out according to Example 2, but the medium temperature is 10 ° C. Exit 87%. The recrystallized product is 95% pure (iodimetry). Melting point 27.2 ° C. Found,%: C 44.18; H 5.29. CyHjoOie. Calculated,% C 44.20; H 5.26. Molecules are of a small weight titrimetric 191 (theoretical 190). Thus, the data obtained, along with the IR spectrum and TLC, give reason to believe that the isolated compound is acetyl-4- (carboxy) -butyryl peroxiso. Example 4. Synthesis of acetyl-4- (1carboxy) butyryl peroxide CH3C (O) OO (O) C (CHg) 3C (O) OH. The test conditions are similar to those of example 3, however, chloroform was used as the solvent. The reaction temperature is 30 ° C. Yield 80%. Example 5. Synthesis of stearyl-p - ("arboxy) propionyl peroxide (CH3) (CH2) 1bC (0) OOS (0) (CH2) 2C (0) OH. The synthesis is carried out similarly to the conditions of example 1. The peroxide is isolated by column chromatography on silica gel with a fraction of 2.5-7.5 microns. The height of the silica gel layer is 10 cm, the column diameter is 2 ohms, eluent hexane:: chloroform is from 10: 1 to 1: 10. The yield of the target product is 60%. Melting point 107 ° C. The method of obtaining acylcarboxiadcanoyl peroxides by acylation of hydrogen peroxide using cyclic aliphatic dicarboxylic acid anhydride and an aliphatic monocarboxylic anhydride, which is used by the use of a mer- dyceric acid, which is used by the use of a heart, or by the use of a heart, it can be used by the use of a volume of acylcarbonic acid; -40 ° C in an anhydrous polar organic solvent in the presence of an acid catalyst, for example p-toluenesulfonic acid. The source of information taken into account in the examination. . R. Lombard, G. Schroeder, Bull. Soc. Chem, France, 1964, 542 (prototype).