CS245074B1 - Organic peroxides and/or their mixtures production method - Google Patents

Description

The invention relates to a process for the production of organic peroxides and / or mixtures thereof, suitable as initiators for the polymerization of vinyl monomers, whereby a high yield of the desired product is achieved and the difficulties usually associated with their production are eliminated. In particular, the invention relates to the production of such peroxides, mixed peroxides and mixtures of several types of peroxides, which produce undesired foaming of the reaction mixture or increase the volume of the reaction mixture due to foaming, or formation of organic peroxide emulsions which are difficult to process.

In the following description, the term organic peroxide will often appear. By this is meant not only an individual organic peroxide, but also the end product of the synthesis, which may be a mixture of several peroxides of different types.

Although the production of the above mentioned organic peroxides has long been an industrial technology, it is accompanied by various difficulties. These usually consist of foaming the reacting mixture. Foaming is associated with the hydrolysis of acyl chloride and the subsequent formation of alkali salts of higher fatty acids, which are known to be effective emulsifiers of the reaction components. Since the synthesis of organic peroxides takes place in a phase heterogeneous reaction medium, the necessary intensive mixing, together with the emulsifier formed, ultimately results in a strong undesired foaming of the reaction mixture. The foaming of the reaction mixture during the synthesis can be stopped by the addition of a mineral acid, but the peroxidation reaction itself also stops and in such cases is achieved! substantially lower organic peroxide extracts. In the case of less foam formation, the final reaction mixture is obtained in the form of a stable emulsion. It breaks down only very slowly. It can be accelerated by some chemical process, e.g. acidifying the reaction mixture. However, such a procedure complicates the technology, increases costs, enforces additional equipment and additionally, increases salinity and chemical aggressiveness of the wastewater. A major problem is also the separation process itself, whether it is the separation of the liquid organic phase or the isolation of the solid product.

For the industrial production of the present organic peroxides, discontinuous and continuous processes are used, employing a variety of solutions to problems related to the high foaming of the reaction mixture during synthesis and the distribution of the emulsions formed after the synthesis.

Disclosed is the continuous production (NSR Pat. 1192 181) of diacyl peroxides (dilauroyl peroxide, dibenzoyl peroxide) by a solvent process together with solvent recovery (heptane). The reaction temperature is high (40 to 65 ° C) to achieve a high concentration of organic peroxide in solution. The phases separated only after the reaction mixture was subsequently cooled to -5 to 0 ° C. The yields obtained are in the range of 88-92%.

Lauroyl chloride or decanoyl chloride is reacted with sodium hydroxide and hydrogen peroxide in a continuous manner at a high reaction temperature up to 20 ° C above the melting point of the respective peroxide (German Pat. No. 1,643,599). The phase separation requires handling of the molten diacyl peroxide and subsequent solidification thereof on the cooled drum of the flaking machine.

A similar process for the continuous production of dilauroyl peroxide (German Pat. No. 2,928,020), but without a solvent process, utilizes a lower reaction temperature (0-20 ° C), with a residence time proportionately longer (20-25 min). The amount of incoming NaOH and H 2 O 2 is regulated by its concentration in the leaving reaction mixture. A 30 to 60% excess of NaOH and H 2 O 2 is used in the reaction, which also allows crude lauroyl chloride containing 101 to 110% of saponifiable chlorine. A small amount of heavy metal salt such as e.g. FeSOd to suppress eventual foaming in the separator. At the end of the reaction, hot water is added to the treated mixture to melt the dilauroyl peroxide and to break up the resulting emulsion. After phase separation, the dilauroyl peroxide is flaked on a cooled roller of the flaking machine. Approximately 95% yields are obtained.

In the process according to German Patent 1,518,741, diacylperoxides C8 to Cle are produced in a solvent manner in the form of a concentrated solution in the gasoline fraction (b. V. 35-85 ° C). Addition of PCl 3 and an acid anhydride derived from reacting acyl chloride is used to prevent foaming. At a reaction temperature of 5 to 30 ° C and a time of 2 to 20 min, the product is in the form of an emulsion which can only be broken up by adding a considerable amount of warm water. Nevertheless, an increase of about 5% in volume is observed by foaming the reaction mixture.

A more recent continuous process for the production of dilauroyl peroxide (German Pat. No. 1,668,355) utilizes in its solvent process the addition of lauric anhydride and PCI3 as suds suppressors. A constant concentration of NaOH (0.2 to 0.8 NJ and H 2 O 2 (0.2 to 1.2 wt% J) is maintained in the reaction mixture. The reaction is carried out at temperatures of 5 to 35 ° C and with a residence time of 5 to 25 minutes. The reaction mixture leaves the system in the form of an emulsion, and up to four times the amount of warm water is added thereto so that the resulting temperature of the mixture leaving for separation is 36-42 ° C. Subsequent separation of the reaction mixture and purification of the product is complicated and time consuming. the yield (96%) hardly outweighs the laboriousness and potential gambling of the cleaning operation.

The safety of handling diacyl peroxides will be increased if these substances are phlegmatized. According to the procedure (USSR auto-certificate 528 741) mixtures of diacyl peroxides are produced from a mixture of chlorides of the fatty acid fraction. In the production of peroxides, a 10% excess of acylchlorides is used. Higher acyl chlorides remain after hydrolysis as phlegmatizers in the peroxide product. The reaction is carried out at a temperature of 6 to 14 ° C in the presence of a solvent, respectively. The separation of the reaction mixture into phases is slow, as evidenced by the long separation time (45 min.). The yield according to the exemplary embodiments is about 75%.

The desensitization of diacyl peroxides can also be achieved by the addition of an oily substance, such as e.g. phthalic acid esters, phosphate esters or silicone oils (NSR Pat. 1768 199) in an amount such that the content of e.g. dilauroyl peroxide was 50%.

The above procedures have a number of drawbacks, some of which occur in several of the above-mentioned procedures, others affect! specific procedure.

Many procedures use! suitable solvents for the production of organic peroxides, such as e.g. petrol (NSR Pat. 1 518 741; NSR Pat.

668,355J, heptane (German Pat. No. 1,192,181) and methyl ethyl ketone (USSR auto-certificate 528,741), respectively. However, the use of solvents entails either the need for their regeneration or their laborious removal from the end product associated with the problems of waste water or air pollution.

A disadvantage of several patented processes is or high reaction temperature (NSR Pat. 1192 181; NSR Pat. 1 643 599), high phase separation temperature (NSR Pat. 1 518 741; NSR Pat. 1 668 355), respectively. work with peroxide melts (German Pat. No. 1,643,599; German Pat.

928 020 J, which represents a significant risk of the occurrence of emergency conditions.

According to German Pat. No. 1,668,355 and German Pat. No. 2,928,020 it is necessary to regulate the amounts of NaOH and H2O2 introduced according to their concentration in the outgoing reaction mixture, which is associated with the provision of complicated measurement and control technology and increased demands on the operation of the device.

The use of PCl 3 in conjunction with an acidic anhydride derived from reactive acyl chloride (NSR Pat. 1,518,741; NSR Pat. 1,668,355), which partially helps the foaming of foams in synthesis, is disadvantageous, in particular from the point of view of handling harmful substances.

A disadvantage of virtually all of the processes cited is the complex and time-consuming separation, purification and possibly drying of the resulting product, which requires the installation of additional equipment in the process.

Many of the patents are also relatively energy intensive, especially if the reaction mixture is first heated (mostly hot water) and then cooled rapidly (NSR Pat. 1192 181; NSR Pat. 1 668 355; NSR Pat. No. 2 928 020).

The disadvantage of the USSR 528 741 process is, in particular, the work of an excess of relatively expensive acyl chloride, with much of it being unproductively degraded. A disadvantage is also the low reaction temperature and the associated longer reaction time as well as very slow separation of the reaction mixture.

In the case of the procedure under NSR Pat. number 1 768 199 is disadvantageous high consumption of relatively expensive phlegmatizers.

The disadvantages of the above procedures are eliminated! The process according to the invention, wherein the process for producing organic peroxides and / or a mixture of peroxides with increased thermal stability of the general formula

O O! <-C -U ..... O t; R 'in which

R 1 is alkyl or a straight or branched chain alkoxy having a carbon number of 8 to 18, cyclohexyl, alkylcyclohexyl having a carbon number of 7 to 12, benzyl, phenyl, halogenated phenyl,

R 'is phenyl, halogenated phenyl, benzyl, alkylbenzyl, cyclohexyl. alkylcyclohexyl having 7 to 12 carbon atoms, straight or branched chain alkyl or alkoxy having 4 to 18 carbon atoms, wherein R R-R “or is different, by reacting at least one halogenated anhydride of the formula RCOX, respectively; R 'COX, where X is a chlorine or bromine atom, with hydrogen peroxide in an alkaline environment at temperatures of -5 ° C to 60 ° C with efficient mixing and co-initiation of auxiliaries suitable as initiators (co-polymerization of vinyl monomers) presence of metal compounds of groups IIa, IIb of the Periodic Table of the Elements, which are added at the beginning and / or during the reaction in one portion or in portions or continuously in an amount of 1 to 150 mol%, preferably 3 to 50 mol%, calculated to the halide deployed.

The main advantage achieved in this way is that the undesirable increase in the volume of the reaction mixture or its foaming is avoided completely and the formation of hardly processable emulsions of organic peroxide is avoided.

The organic peroxide produced according to the invention is in the form of a wet, free-flowing granular, spherical or fine-flocculated substrate having a size of 0.1 to 10 mm, but most often 0.5 to 3 mm.

The product contains 25 to 70 seconds, depending on reaction conditions and separation efficiency

percent of active substance (organic peroxide). The rest is occluded water and water-insoluble alkaline earth metal salts of fatty acids. Such a form of organic peroxide is particularly advantageous for undemanding, safe and sufficiently long storage. The high moisture content and the alkaline earth metal fatty acid salt effectively phlegmatizes the organic peroxide and makes it insensitive to spontaneous disintegration as well as to friction or friction disintegration. strike. Such a product can be safely stored at temperatures of ¹ to 45 ° C. It goes without saying that freezing temperatures will in no way affect product quality or storage safety.

A further significant advantage of the peroxide production according to the invention is that the reaction is carried out in a simple, technically undemanding production plant, consisting of a reactor and a filtration device. In all, the operations of diluting the outgoing reaction mixture, breaking the emulsion and treating the concentrated organic peroxide solution in the solvent or purifying and treating the organic peroxide melt are eliminated.

The synthesis reaction is feasible over a wide temperature range of -5 to + 60 ° C, preferably 20 to 40 ° C, and can be carried out batchwise, semi-continuously as well as continuously with high yields (80-90% of the desired organic peroxide). Synthesis conditions virtually eliminate the risk of emergencies.

The product produced is readily separable from the mother liquor by simple filtration. The resulting wet bulk substrate after optional washing with water can either be used immediately in polymerization or stored.

The organic peroxide produced by this process is particularly suitable for use under conditions where moisture is not present in the defect. A typical use will be in the suspension or emulsion polymerization or copolymerization of vinyl monomers.

The presence of alkaline earth metal salts of fatty acids, which act as phlegmatizers in the final peroxidic product, causes the polymer to have improved thermal stability, since the alkaline earth metal fatty acid salts are effective thermal stabilizers of tartaric (copolymers). The alkaline earth metals thus perform a dual role: first as phlegmatizers in organic peroxide, and after and after polymerization as thermal stabilizers (cosopolymers).

In contrast to the above processes, the production of organic peroxides according to the invention is substantially less energy-intensive, in particular due to the fact that the complicated separation and subsequent treatment of the peroxide product (melting by adding hot water, after cooling, vigorous cooling, solvent recovery, etc.).

By selecting suitable chlorohydrides, their ratio to each other, and the choice of reaction conditions in the synthesis, it is possible to efficiently alter the chemical composition of the peroxide compounds in the final product. In this way, it is possible to produce organic peroxides suitable as initiators for intradecimal polymerization, which by their composition are adapted to the polymerization of a particular (co) polymer system.

The process according to the invention thus makes it possible to produce a suitable (co) polymerization initiator in a single reaction step, which is an advantage over the previously used initiation systems, which are prepared by mixing several individual organic peroxides up to just before the (co) polymerization process. The process according to the invention is therefore reversible, reduces the labor and handling of organic peroxides and increases the technological safety of the process.

Example 1

The organic peroxides are prepared in a 2 L glass reactor equipped with a duplicator for heating, a glass cooling coil, a glass paddle stirrer at 200 to 700 rpm, a thermometer, a contact thermometer for cooling control, a reagent inlet, and a handling port. The reactor is charged with 1000 g of distilled water, 10 g of an aqueous solution of 10% by weight MgSCl, 0.96 mol of NaOH in the form of 81.0 g of an aqueous solution of 47.4% by weight, 0.48 mol of H2O2 in the form of 45.7 g of an aqueous solution having a concentration of 35.7 wt. and 0.24 moles of CaCl 2.

After the peroxidation aqueous phase was heated to 30 ° C, a mixture of lauroyl chloride (0.72 mole, 157.5 g) and 2-ethylhexyl chloroformate (0.08 mole, 15.4 g) was added. After 15 min after the addition of the organic chlorohydrides, the reaction is complete, the product is collected by filtration, washed with water and analyzed. 307 g of granules of about 1 mm in size are obtained. Analysis yielded 68.5 wt. with an organic peroxide content of 35.6 wt. in simplified conversion to dilauroyl peroxide (DLP).

Example 2

The procedure is as in example no. 1, but instead of CaCl2, 0.24 mol of BaCl2, which is 58.6 g of crystalline dihydrate, is used. After 15 min after the addition of the organic chlorohydrides, the reaction is complete, the product is collected by filtration, washed with water and analyzed. 339 g of fine granules of about 0.5 mm in size are obtained. Analysis showed 92.6% yield.

and the product contains 43.6 wt. organic peroxide (calculated as DLP).

Example 3

The procedure is as in example no. 1, but instead of CaCl2, MgCl2 is used in an amount of 0.24 mol, which is 48.8 g of crystalline dihydrate. After a reaction time of 20 minutes, a granular product of 274 g is isolated. The yield was 67.7 wt%, the organic peroxide content was 39.4 wt%. (calculated as DLP). Example 4

The procedure is as in example no. 1, but instead of CaCl2, 0.24 mol of MgSO4 is used, which is 59.2 g of crystalline heptahydrate. After a reaction time of 20 minutes, the reaction mixture is filtered. 346 g of a product with an organic peroxide content of 34.6% by weight are obtained. (calculated as DLP) with a yield of 75.1 percent.

Example 5

The procedure is as in example no. 1, but instead of CaCl2, ZnCl2 is used in an amount of 0.24 mol, or 32.7 g. After a reaction time of 10 min, 323 g of free-flowing granules having a content of 32.4% by weight are obtained by filtration of the reaction mixture. of the active substance (calculated as DLP). The yield of organic peroxides is 67.9%.

Example 6

The procedure is as in example no. 1, but cadmium sulphate g is used instead of CaCl2

3CdSO4.8H2O, respectively. CdSCh. - H2O in an amount of 0.24 mol, which is 61.5 g. After 10 minutes of reaction, the reaction mixture is filtered to give 360 g of product as white balls of 2-3 mm in size. The peroxide yield was 75.4%, the active substance content was 33.4% by weight. (calculated as DLP).

Example 7

The procedure is as in example no. However, calcium formate (HCOO) 2 Ca in an amount of 0.24 mol (31.2 g) is used instead of CaCl 2. After a reaction time of 10 min, 341 g of product are isolated in the form of about 1 mm granules in a yield of 61.9% and an active compound content of 28.9% by weight. (calculated as DLP). Example 8

The procedure is as in example no. 1, but calcium lactate (CH 3, CHOH, COO) 2 Ca is used instead of CaCl 2. 5H2O at 0.24 mol (74.0 g). After a reaction time of 20 minutes, the reaction mixture is separated by filtration. 328 g of product are obtained in the form of about 1 mm of granule 245074 drug. The organic peroxide yield was 70.0 percent and the product contained 34.0 wt. peroxides (calculated as DLP).

Example 9

The procedure is as in example no. 1, but instead of CaCl2, barium citrate is used in an amount of 50 g. After a reaction time of 20 minutes, the reaction mixture is separated by filtration. 323 g of product are obtained in the form of about 1 mm granules. The analysis showed a peroxide content of 35.5 percent by weight. (calculated as DLP), giving a total conversion of 72.0%.

Example 10

The procedure is as in example no. 1, but instead of calcium chloride alone, a combination of BaCl 3 is used. 2H 2 O (0.06 mol;

14.7 g] and anhydrous CaCl 2 (0.06 mol; 6.7 g). After a reaction time of 20 minutes, the reaction mixture is filtered. 313 g of fine granules with 40.7 wt. organic peroxides (calculated as DLP) with a total conversion of 79.9%.

Example 11

The procedure is as in example no. 1, but Ba (OH) 2 is used instead of NaOH and CaCl 2.

. After 20 min reaction time, the resulting organic peroxides are filtered off to give 380 g of a voluminous powder containing 30.1% by weight of organic peroxides (calculated as DLP), with their total yield is 17.8%.

Example 12

The procedure is as in example no. 1, but Ca (OH) 2 is added instead of CaCl2 and part of NaOH. NaOH (0.80 mol; 67.5 g of a 47.4 wt% solution) and Ca (OH) 2 (0.24 mol;

17.8 (g) together with other reactants. After 20 minutes of reaction, the reaction mixture is filtered to give 400 g of a fine powder which contains 30.0 wt. organic peroxides (calculated as DLP) with a total yield of 75.2%. Example 13

The procedure is as in example no. 2, but the excess NaOH calculated on organic chlorohydrides is 50% relative. With such a large excess of sodium hydroxide, no reaction of the reaction mixture is observed,

Working up of the reaction mixture yielded 338 grams of product in the form of small granules with an organic peroxide content of 37.9 percent by weight. (calculated as DLP) with an overall yield of 80.4%.

Example 14

The procedure is as in example no. 2, but the theoretically required amount of NaOH, i.e. a 0% excess, is taken into the reaction batch.

After a reaction time of 20 minutes, the product was collected by filtration. 293 g of granules having a size of 1 to 2 mm, containing 48.4% by weight, are obtained. organic peroxides (calculated as DLP) with a total conversion of 89.0%. Example 15

The procedure is as in example no. 1, but the reaction temperature was lowered to 20 ° C. After a reaction time of 30 minutes, the product is separated from the reaction mixture by filtration. 262 g of free flowing granules are obtained with a content of 40.0% by weight. organic peroxides (calculated as DLP) with a total conversion of 65.8%. Example 16

The procedure is as in example no. 1, but the reaction temperature is raised to 40 ° C. After a reaction time of 10 minutes, the product is separated from the reaction mixture by filtration. 277 g of free-flowing granules are obtained, containing 35.0 wt. organic peroxides (calculated as DLP) with a conversion of 60.9%. Example 17 (comparative)

Progressing. as in example no. 1, but CaCl2 is omitted from the batch and no other compound is added. After 5 min after the addition of the organic components, the reaction mixture starts to foam strongly and the reaction must be interrupted by emergency. The reaction mixture is perfectly emulsified and the product must first be broken with a strong acid emulsion. The separated product is a sticky and poorly filterable material. 261 g of product are obtained with a content of 53.2% of active substance (calculated as DLP), which represents 87.4% conversion.

Example 18

The procedure is as in example no. 2, but instead of 2-ethylhexyl chloroformate, cetyl chloroformate in an amount of 0.08 mol (24.4 g) and an unchanged amount of lauroyl chloride are used. The reaction is without problems. After 10 min, the organic peroxide formed is isolated by filtration. 335 g of product are obtained in the form of small spheres of about 0.5 mm, the filterability being excellent. The active substance content is 43.8% by weight. (calculated as DLP), total yield 92.1%.

Example 19 (comparative)

The procedure is as in example no. 18, but the reactants of the shaft is omitted, water-soluble divalent metal salt of ¹ (BACH). During the reaction already from 8 min considerable foaming of the reaction mixture occurs. After 20 min, the reaction was stopped. Separation of the formed organic peroxide by filtration is extremely difficult. 484 g of a viscous and difficult to handle product with an active compound content of 25.8% by weight are obtained. (calculated as DLP) with a total peroxide yield of 78.2%.

Example. 20

The procedure is as in example no. 2, but instead of 2-ethylhexyl chloroformate, cetyl chloroformate was used in an amount of 0.08 mol (24.4 gj) and an equivalent amount of stearyl chloride (0.72 mol; 216.8 gj) instead of lauroyl chloride. The filtration is rapid and easy to give 475 g of product in the form of tiny spheres with an active ingredient content of 29.2% by weight (calculated as distearoyl peroxide), the total yield of organic peroxides being 01.6%. .

Example 21 (comparative)

The procedure is as in example no. 20, but the water-soluble divalent metal salt (BaCl2) is omitted from the reactant feed. During the reaction, the volume of the reaction mixture gradually increases due to foaming. After 30 minutes, the reaction was stopped. Separation of the formed solid organic peroxide by filtration is only possible with difficulty. 587 g of product are obtained in the form of a viscous sludge with an active substance content of 14.4% by weight. (calculated as distearoyl peroxide), the total yield of organic peroxides being 37.7 θ / o.

Example 22

The procedure is as in example no. 2, but instead of the chlorohydride mixture, only lauroyl chloride alone is used in an amount of 0.80 mol, which is 175.0 g. After 10 minutes after the end of the lauroyl chloride addition, the reaction is complete and the product is collected by filtration. 386 g of product are obtained in the form of granules of about 2 mm in size. Analysis showed that the yield of dilauroyl peroxide was 84.5%, and its concentration in the product was 41.3%.

Example 23 (comparative)

The procedure is as in example no. 1, but instead of a mixture of 2-ethylhexyl chloroformate with lauroylchloridoin, only lauroyl chloride alone is used in an amount of 0.80 moles (175 gj and omitted CaCl2.) After 4 minutes after the addition of lauroyl chloride, the reaction mixture begins to increase The whole reaction mixture is in the form of a foamed emulsion and to isolate the product it is necessary to first break the emulsion with a strong acid.The separated product is a soft, waxy to butter-like consistency and very difficult to filter to give 255 g of product with 52.3% content of active substance, which represents 83.7% conversion.

Example 24

A 100 L pear-shaped glass reactor equipped with a propeller stirrer and a stainless steel cooling coil, a glass thermometer, reagent dispensing openings and bottom outlet was charged with NaOH (48 mol), in the form of 4,000 g of 48 aqueous solution, 0% by weight, H2O2 (24 moles), in the form of 2 287 g of an aqueous solution of 35.7% by weight, MgSOt in an amount of 200 g of an aqueous solution of 10% by weight, CaCl2 (12 moles) in the form of 1 332 g of anhydrous powder and 60 kg of demineralised water.

After the solution of the peroxidation aqueous phase in the reactor was brought to 20 ° C, a mixture of 7.876 g of lauroyl chloride (36 mol) and 771 g of 2-ethylhexyl chloroformate (4 mol) was started with vigorous stirring and cooling. The addition time was 1 minute and cooling maintained the reaction temperature of 33 ° C for an additional 20 minutes. The contents of the reactor are then discharged, the product is separated by filtration and the filter is washed thoroughly with water. 15.8 kg of loose free-flowing granules of about 1 mm in size, containing 43.9 wt. organic peroxides (calculated as DLP).

The mixture of organic peroxides thus prepared is used as a polymerization initiator for suspension copolymerization of vinyl chloride / vinyl acetate. 8.5 m ^{3 of} an aqueous solution of hydroxypropylmethylcellulose at a concentration of 0.47 kg / m ³ are pumped into a 15 m ³ autoclave, 35 kg of trichlorylene and 12.2 kg (11 moles of organic peroxide) polymerization initiator described above are added. The autoclave vapor is inerted with nitrogen and 549 kg of vinyl acetate and 2800 kg of vinyl chloride are then pumped into the autoclave. After pumping is complete, the autoclave is heated to 63 DEG C. with stirring through a duplicator. After 8.5 hours after heating, the pressure in the autoclave 11a drops to 0.4 MPa and the unreacted monomers are degassed and, after isolation of the copolymer powder, this is analyzed. At the same time, a product from conventional production prepared with the initiators dilauryl peroxide (DLP) and dicetyl peroxide dicarbonate (P-24) (manufactured by AKZO) is analyzed. The results are shown in the following table:

table

property

Example podium initiator

Commercial Initiator (DLP - | - P - 24]

Sieve Analysis (Wet) - Site Balance (%)

0.250 mm 1

0.200 mm 1

0.160 mm 4

0.100 mm 47

0,63 mm 32 overflow 15

Bulk density (kg / m ³ ) 643

Total whiteness * (%) 69.0

Color stability in calendering (color grade) ** after 15 min calendering 2 after 30 min calendering 3

635

66.3 * Proportion of reflected light from powder surface after 100 min exposure! for 130 ° C ** According to color standards

Claims (2)

Process for producing organic peroxides and / or mixtures of peroxides with increased thermal stability of the general formula O O II II R ‘- C-O-O-C-R 'in which R‘ is straight or branched chain alkyl or alkoxy having 8 to 18 carbon atoms, cyclohexyl, alkylcyclohexyl having 7 to 12 carbon atoms, benzyl, phenyl, halogenated phenyl, R 'is phenyl, halogenated phenyl, benzyl, alkylbenzyl, cyclohexyl, alkylcyclohexyl having 7 to 12 carbon atoms, straight or branched chain alkyl or alkoxy having 4 to 18 carbon atoms, by reaction of at least one halogenated anhydride OF THE INVENTION of the general formula R‘COX, resp. R 'COX, where X is a chlorine or bromine atom, with hydrogen peroxide in an alkaline environment at temperatures of -5 ° C to 60 ° C with efficient mixing and co-initiation of auxiliaries suitable as initiators (co-polymerization of vinyl monomers, characterized in that the reaction takes place) in the presence of Group IIa, IIb metal compounds of the Periodic Table of the Elements, which are added initially and / or during the reaction in one portion or in portions or continuously in an amount of 1 to 150 mol%, preferably 3 to 50 mol%, calculated on mounted halide. 2. The process of claim 1 wherein the reaction is carried out in the presence of at least one magnesium, calcium, strontium, barium, zinc, cadmium selected from oxides, hydroxides, salts of organic and inorganic acids.