DE1243666B - Process for the preparation of aliphatic or aromatic diacyl peroxides - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

C07c

German class: 12 ο-11

Number: 1243 666

File number: M 50712IV b / 12 ο

Filing date: October 27, 1961

Opened on: July 6, 1967

Process for the production of diacyl peroxides of the general formula R - CO - OO - OC - R in the R represents an aliphatic or aromatic radical are known. These procedures are based on the reaction of acyl halides with hydrogen peroxide in the presence of an alkali hydroxide. These Implementation takes place according to the general equation

2 RCOX + H ₂ O ₂ + 2 MeOH

- * - (RCOO) ₂ + 2 H ₂ O
(X = Cl, Me = Na or K).

2MeX

(1)

The following undesirable side reactions can occur in this reaction:

Acid Chloride Hydrolysis:

RCOX + H ₂ O ■ + ■ RCOOH + HX (2)

Decomposition of the hydrogen peroxide:

2 H ₂ O ₂ - * - 2 H ₂ O + O ₂ (3)

The reaction according to (1) is generally strongly exothermic, whereas reactions (2) and (3) are are favored by an increase in temperature, especially in an alkaline medium. The temperature increase but also favors the decomposition of the known heat-sensitive peroxides. From this In fact, the conclusion is that maintaining low temperatures is the most important thing Promote procedures.

In fact, the efforts of technology are directed towards this end. The method according to US Pat. No. 2,771,492 works e.g. B. between -10 and +5 ⁰ C, the method of the German patent specification 934 592 uses temperatures from 0 to 10 ⁰ C, and according to LF Fieser in "Journal of American Chemical Society", Volume 70 (1948), p. 3174 , the maximum temperature is 10 ⁰ C.

After G rigee in Houben-Weyl, "Methods of Organic Chemistry," 4th Edition, Volume VIII (1952), page 40, aliphatic diacyl peroxides are produced at temperatures from -10 to -5 ⁰ C.

But if you work with low temperatures, the reaction rate is very low and is on average 1 hour.

It has now been found, surprisingly, that this reaction occurs at noticeably higher temperatures can be carried out without the yield falling, and thus the reaction time substantially gets shorter.

Process for the preparation of aliphatic or
aromatic diacyl peroxides

Applicant:

MONTECATINI Societä Generale per

rindustria Mineraria e Chimica, Milan

(Italy)

Representative:

Dr. Dr. J. Reitstötter and Dr.-Ing. W. Bunte,

Patent Attorneys, Munich 15, Haydnstr. 5

Named as inventor:

Robert Hill,

Pier Luigi Mondellini,

Giorgio Sugni, Milan (Italy)

Claimed priority:

Italy of October 31, 1960 (18 845)

The present process for the preparation of aliphatic or aromatic Diarylperoxyden by reaction of acyl halides with hydrogen peroxide in the presence of potassium or sodium hydroxide is characterized in that one carries out the reaction at a temperature between 50 and 6O ⁰ C and then the reaction mixture is rapidly cooled to room temperature.

At this temperature the reaction can take place in such a short time - it is only a few minutes - be ended so that the process can also be carried out continuously without great difficulty. The present invention therefore also relates to the continuous implementation of the process.

If you do not work continuously, you should preferably proceed as follows:

Aqueous hydrogen peroxide and the acyl halide to be an aqueous, added simultaneously with continuous stirring to 30 to 5O ⁰ C heated sodium or potassium hydroxide. The reaction temperature is - as already mentioned - between 50 and 6O ⁰ C. After 30 seconds to 5 minutes, the reaction mixture is cooled to room temperature.

When working continuously, the acyl halide, Alkali hydroxide and hydrogen peroxide

709 609/449

at the same time introduced into a vessel, the temperature of which is kept at 50 to 60 ° C. The secluded The end product is filtered off, washed with water and air-dried.

The good yields obtained under these operating conditions show that reaction (1) of the Diacyl peroxide formation is noticeably favored compared to the side reactions (2) and (3).

The ability to work at a higher temperature is of particular importance the fact that a degradation of the diacyl peroxides formed occurs when they reach the temperatures mentioned be suspended for some time. However, this degradation is due to rapid cooling after it has finished Reaction prevented.

It could also be found that in the manufacture of diacyl peroxides, long chain saturated Fatty acids such as B. lauric, myristic, margaric and stearic acids the present process This can be improved considerably if the warm mixture is used after the reaction has ended preferably acidified with sulfuric acid until it contains 1 to 2% free sulfuric acid.

Form long-chain saturated aliphatic fatty acids in the manufacture of diacyl peroxides This is because in the known processes which do not provide for acidification, they are very stable during the reaction Foams and emulsions that are very difficult to remove.

The present method makes it possible with only one washing and subsequent filtration to obtain technically perfect end products.

The following table shows test results in the production of lauroyl peroxide at a reaction temperature of 55 to 6O ⁰ C and different long reaction time.

example reaction time
(Minutes) Purity of
End product (4) Yield,
based on
Lauroyl chloride
7o 6th
1
3
4th 0.6 to 1
2
5
5 90
92
78.4
75 89.5
92.6
79.5
74

If lauroyl peroxide is produced by known processes, the reaction time is approximately 1 hour, and to get a technically usable product you have to do it four times in a row wash out. In contrast, the method according to the present invention is already in a Reaction time of 2 minutes achieves optimal results, and after acidification is only one time Wash with water necessary.

It was found that the course and yield of the process according to the invention by changes is not significantly influenced in the quantitative ratio of the reactants.

On the other hand, it is of decisive importance, especially in the case of discontinuous operation, how the respondents are brought together. Namely, it was found that the acyl halide and the hydrogen peroxide at the same time introduced into the alkali solution warmed to room temperature Need to become.

According to the current state of the art, lauroyl peroxide is produced as follows:

To 100 parts of 33.5% aqueous solution, cooled to about 5 ⁰ C hydrogen peroxide solution are added 3.2 parts of a 3O ° / ^s oig aqueous potassium hydroxide solution under vigorous stirring and then 102.8 parts of the same 30 ° / ₀ aqueous potassium hydroxide solution and 123 , 3 parts of lauroyl chloride introduced. Entry takes 1 hour, the temperature being kept at -7 to -3 ° C. After filtering, the end product is washed four times with water at room temperature, stirring for 30 minutes with about 2500 ecm of water each time, suction and drying of the finished product in the air. This gives 106 parts of 93.1% strength dilauroyl peroxide. The yield, calculated on lauroyl chloride, is 87.8%

Dibenzoyl peroxide is produced in the following known manner:

To a mixture of 505 parts of a 5.23% strength aqueous hydrogen peroxide solution and 505 parts of 6.65% strength aqueous sodium hydroxide ^it, which is cooled to 0 ° C and is continuously stirred, are employed 112.4 parts of benzoyl chloride in the course of 120 minutes .

The temperature is kept between 0 and 3 ^{° C. during the addition.} The end product is filtered off, washed with water and air-dried.

This gives 94.0 parts of 97.4 ° / ₀ sodium dibenzoyl peroxide; Yield calculated on dibenzoyl chloride, 94.3%

The process according to the invention will be explained in more detail with the aid of the following examples.

example 1

600 parts of a 4.5% strength aqueous hydrogen peroxide solution and 300 parts of lauroyl chloride are added simultaneously to 300 parts of an aqueous 23.7% strength sodium hydroxide solution which is heated to 45 ° C. and stirred continuously. Then maintaining the temperature between 50 and 6O ⁰ C, are after 2 minutes, 300 parts of 13.7% aqueous sulfuric acid, the mixture is rapidly cooled to room temperature, the reaction product is nitrided off, washed thoroughly with water and dried on the Air.

275 parts of 92.0% strength dilauroyl peroxide are obtained in this way; Yield calculated on lauroyl chloride 92.6%; F. = 52 to 54 ° C.

Example 2

379.3 parts of 3.3% aqueous hydrogen peroxide and 174.4 parts of lauroyl chloride are heated at the same time 268 parts of a 21.5 ° / ₀ by weight to 5O ⁰ C and constantly stirred potassium hydroxide solution was added. The temperature is kept at 45 to 55 ^° C. for 3 minutes, then 856 parts of 6.5% strength aqueous sulfuric acid are added and the mixture is immediately cooled to room temperature. The reaction product is separated off and washed with water and air-dried. This gives 159.1 parts of 88 ° / _o sodium Dilauroylperoxyd, yield, calculated on chloride, 87.8 ⁰ J _0; F. = 50 to 53 ° C.

Example 3

600 parts of a 4.5% strength aqueous hydrogen peroxide solution are added simultaneously with 300 parts of lauroyl chloride to 300 parts of 23.6% strength ^{sodium hydroxide solution heated to 47 °} C. and kept in motion. The temperature is held for 5 minutes at 57 to 6O ⁰ C, then 300 parts of 13.7% strength are

Sulfuric acid was added and the mixture was rapidly cooled to room temperature. The end product is separated off, washed, filtered and air-dried. 227 parts of 78.4% strength dilauroyl peroxide are obtained. Yield 79.5 ° / _0; F. = 49 to 51 ⁰ C.

Example 4

600 parts of a 4.5 ° / _o aqueous hydrogen peroxide solution and 300 parts of lauroyl chloride are added to 300 parts of 23.6% ig ^it which is heated to 45 ⁰ C and stirred continuously at the same sodium hydroxide solution was added. The temperature is kept for 5 minutes on about 55 to 58 ⁰ C and then sets 300 parts to 13.7 ° / _o sulfuric acid. The mixture is rapidly cooled to room temperature, the reaction product separated off, washed with water and air-dried; 269 parts of 75.0% dilauroyl peroxide are obtained. Yield 74.0%; F. = 47 to 50 ⁰ C.

Example 5

1090 parts of lauroyl chloride A, 1090 parts of 24.3% strength sodium hydroxide solution B and 2180 parts of 4.5% strength aqueous hydrogen peroxide C are continuously introduced into reaction vessel 1 of the drawing, which is provided with a stirrer, through a common inlet. The capacity of the reaction vessel 1 and the container 2 is such that they allow a residence time of the reaction mixture of 5 minutes. Both vessels are kept at a constant temperature of 55 to 60 ⁰ C. The mixture is then passed into the vessel 3, the temperature of which is maintained also between 55 and 60 ⁰ C, after which there per hour 1090 parts of 15 _o ^e ig aqueous sulfuric acid D are introduced into the system ° /. In the container 4, the mixture is rapidly cooled ^{to 15 to 20 ° C. with constant stirring and the addition of ground ice.} The crude peroxide, which is obtained in the form of colorless grains, the size of which depends on the stirring speed in the container 4, is separated from the mother liquor in the centrifuge 5, carefully washed with water F and then dried at room temperature by means of a stream of air; the still moist, raw peroxide is deducted from G and the mother's arbor from H. 986 parts of 86% dilauroyl peroxide are thus obtained per hour, which corresponds to a yield of 85.4%, calculated on the halide used. F. = 50 to 53 ⁰ C.

Example 6

The procedure is as in Example 5, with the exception that the reaction vessels have a capacity which allows a residence time of 0.5 to 1 minute. Every hour, giving 987 parts of 90 ° / ₀ owned Dilauroylperoxyd. Yield, calculated on the halide, 89.5%. F. = 51 to 53 ⁰ C.

Example 7

198.2 parts of a 5.1 ° / _o aqueous hydrogen peroxide be a 9.8 ° / _o by weight, 65 parts of caproyl chloride while 166.4 parts heated and to 47 to 48 ⁰ C, where constantly stirred sodium hydroxide solution. The temperature of the mixture is ^{kept at 50 °} C. for a further 2 minutes, then cooled to room temperature. 55.9 parts of 96% strength dicaproyl peroxide are obtained. The yield is accordingly 93.6%, calculated on the halide. F. = 18 to 2O ⁰ C.

Example 8

120 parts 5, l% aqueous hydrogen peroxide and 36.1 parts Isovalerychlorid simultaneously 125.1 parts of a 9.8% strength at 45 ⁰ C and held in heated vigorous agitation sodium hydroxide solution added. The temperature is between 50 and 54 ⁰ C

ίο held. After 2 minutes, the mixture is rapidly cooled to 20 ⁰ C and the crude product was separated in a separatory funnel, first with 10% aqueous sodium carbonate solution and then thoroughly washed with water. 18 parts of 87% diisovaleryl peroxide which is liquid at room temperature are obtained. Yield calculated on the halide, 51.7%

Example 9

289 parts of 14.4% hydrogen peroxide and 224.8 parts of benzoyl chloride are simultaneously ig ^e, added to 660 parts of a 10% n sodium hydroxide solution, maintained at 5O ⁰ C and in constant motion. ¹ The temperature is maintained for 2 minutes at 5O ⁰ C and then quickly cools to room temperature. The end product is filtered off, washed with water and air-dried. 182.7 parts of 98.8% strength dibenzoyl peroxide are obtained. Yield, calculated on chloride, 93.1%, m.p. = 104 to 105 ° C.

In Examples 7, 8 and 9 no sulfuric acid is added. Acidification is only in the process of making of diacyl peroxides of long-chain saturated fatty acids, such as dilauroyl peroxide, is necessary because this Product has tensioactive properties in an alkaline medium. According to the invention Processes obtained peroxides can be used as reaction initiators or crosslinking agents. Dilauroyl peroxide can also be used as a bleaching agent.

Claims (4)

Patent claims: 1. A process for the preparation of aliphatic or aromatic diacyl peroxides by reacting acyl halides with hydrogen peroxide in the presence of potassium or sodium hydroxide, characterized in that the reaction is carried out at a temperature between 50 and 6O ⁰ C and then the reaction mixture is rapidly cooled to room temperature. 2. The method according to claim 1, characterized in that one enters the acyl halide and the hydrogen peroxide solution in the same to 5O ⁰ C, heated to 30 alkali metal hydroxide solution and heat the reaction mixture briefly to the reaction temperature. 3. The method according to claim 1, characterized in that the reaction between acyl halide, Hydrogen peroxide and alkali hydroxide within a period of 30 seconds to 5 minutes. 4. The method according to claim 1 and 2, characterized in that in the case of production of diacyl peroxides of long-chain saturated fatty acids, the warm reaction mixture after the end Reaction acidified with sulfuric acid. 1 sheet of drawings