NL8105711A - Organic peroxides prepn - Google Patents

Abstract

Organic peroxides contg. four peroxide gps. and having the formula:- R3 - OO - C(R1)(R2) - OO -2 X (I) where R1 is H, (cyclo)alkyl, aryl, oxyalkylaryl, oxycycloalkyl; R2 is H, (oxy)alkyl, oxyalkylaryl, oxycycloalkyl; is (cyclo)alkyl, aryl, oxyalkyl, oxyalkylaryl, oxycycloalkyl, acyl, aliphatic, cycloaliphatic or aromatic; X is alkylene, alkenylene, alkynylene, oxyalkylene, arylene, arylenedialkyl, arylene dialkenylene, arylenedialkenylene. Examples of (I) are:- alpha, alpha'(2-cumyl peroxy-isopropylidene 2-peroxy) 1,3- or 1,4-diisopropyl benzene. Crosslinking agents for polyolefines and elastomers. The peroxides improve mechanical strength at high temp., reduce fragility at low temp. and solubility in hydrocarbons, improved weathering and age resistance. The vulcanised products have no smell and no efflorescence. The peroxides give shorter hardening times and lower hardening temps., are unaffected by other components and are more stable and less volatile than known peroxides.

Description

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Process for the preparation of organic peroxides with four peroxy groups per molecule.

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This invention relates to a process for the preparation of compounds of the formula 1 of the formula sheet wherein X is an arylene dialkyl group and a tertiary alkyl group.

Such a method is known from the Dutch patent application 65.15413, that the preparation of di- and tetrakis-peroxides with two alkyl peroxy groups on a carbon atom or. with two such pairs, including the a, <x-bis / a- (t-butylperoxy) isopropylperoxyl-1,4-10 diisopropylbenzene, by reaction in the absence of an acid of a mineral bishydroperoxide with an organic hydroperoxide or . with a bis-hydroperoxide the peroxy groups of which are not mineralized. The absence of an acid catalyst was considered essential for the preparation of the alkylidene peroxides derived from a carbonyl compound and an aralkyl-15 hydroperoxide.

These peroxides are useful for initiating radical reactions and for vulcanizing elastomers and cross-linking synthetic resins. However, the transperoxy-20 data takes quite a long time and generally proceeds in low efficiency.

Now, for this kind of peroxides, a simpler preparation in the presence of an acidic catalyst has been found, not based on a slow exchange of a geminal bis (alkyl peroxy) alkane with a non-mineral hydro peroxide, but based on the much faster reaction of such a non-geminal bis-hydroperoxide with a ketone followed by the likewise rapid reaction of the bis (α-hydroxyperoxy) alkane of formula 2 thus obtained with a tertiary alkyl hydroperoxide.

8105711

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According to the invention, a compound of formula 1, wherein R 1 and together with the connecting carbon atom form a cycloalkylidene group, thus compounds of formula 2, wherein A represents an optionally substituted alkylene bridge by a cycloalkanone of formula 3 in the presence of a very and a dewatering agent at a temperature between -30 ° and + 80 ° C with a bis-hydroperoxide according to the general formula Η00-Χ-00Η (with a molar ratio to the cycloalkanone between 1: 1.2 and 1:10) 10, wherein X has the aforementioned meaning, and the compound of formula 4 thus formed in the presence of an acid and a dewatering agent with a tertiary alkyl hydroperoxide of the formula R 1 -OOH with a molar ratio to the compound of formula 2 between 2 : 1 and 15 to react 10: 1, wherein R ^ has the aforementioned meaning.

The formation of α-hydroxyperoxides by reaction of a hydroperoxide with a ketone is known, inter alia from US patent 2,455,569, and it is also indicated therein that these compounds are reacted with a second molecule of hydroperoxide in compounds with two alkyl peroxides. pass groups to one carbon atom. This process necessarily results in compounds having two identical alkyl peroxy groups on the carbon atom, and this US patent, unlike the present invention, also deals with the preparation of compounds having only one pair of such peroxy groups, so not with the preparation of compounds having four peroxy groups per molecule, nor is the use of araliphatic hydroperoxides explained. Moreover, the peroxides according to the invention under the same conditions give more cross-linked polymers than those according to Dutch patent application 65.15413, which swell much less with organic solvents (and in particular with aromatics such as xylene), making them useful for transport pipes and other accessories. for the transportation of such liquids.

8105711 Λ t

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In the first step of the process according to the invention, in a suitable solvent, a cycloalkanone of the formula III is generally reacted with a bis-hydroperoxide of the formula HOO-X-OOH, wherein X has the aforementioned meaning, in a suitable solvent and in the presence of an acid as a catalyst and a suitable dewatering agent such as calcium chloride. This is preferably done at temperatures between -10 ° and + 50 ° C. The molar ratio between bis-hydroperoxide and cycloalkanone is preferably between 1: 1.5 and 1: 5.

The compound of formula 4 thus obtained is reacted in a second phase, also in the presence of an acid and a dewatering agent, with a tertiary alkyl hydroperoxide of the formula R 10 -OH. This also takes place at temperatures between -30 ° and + 80 ° C, preferably between -10 ° and + 50 ° G, if desired in the presence of a solvent.

The molar ratio between compound of formula 4 and monohydroperoxide is preferably between 1: 3 and 1: 5.

Solvents suitable for this preparation are aliphatic cycloaliphatic and aromatic hydrocarbons, optionally substituted by halogen, as well as diethyl ether. Suitable catalysts include hydrochloric acid and sulfuric acid.

The peroxides according to the invention are suitable as vulcanizing agents for saturated elastomers and cross-linking agents for synthetic resins.

Such vulcanization is carried out by heating for 5 to 200 minutes at temperatures between 140 ° and 190 ° C, preferably between 5 and 15 minutes, at temperatures between 150 ° and 180 ° C, in particular when starting from an ethylene-propylene copolymer. Between 0.5% and 10% by weight of peroxide must be incorporated in the elastomer, preferably between 2% and 5% by weight. Vulcanization is particularly good with mixtures containing from 100 parts of ethylene-propylene copolymer 20-80 parts of carbon black, 1-10 parts of zinc oxide, 0.15-0.5 parts of sulfur and 0.005-0.02 gm peroxide.

8105711 S * Λ - 4 - $

The use of the peroxides according to the invention as cross-linkers for synthetic resins is particularly suitable for polyolefins, and in particular for polyethylene, which improves the mechanical resistance at high temperatures, the brittleness at low temperatures and the solubility in aliphatic and aromatic hydrocarbons (also chlorinated). Moreover, this application increases the resistance of the obtained cross-linked polymers to light, weathering and aging. Cross-linking according to the invention is effected by heating for 5 to 60 minutes at temperatures between 100 ° and 200 ° C under pressures of 50-200 kg / cm, preferably 10 to 30 minutes, at temperatures between 145 ° and 165 ° C.

Thereby, between 0.5% and 10% by weight of peroxide must be incorporated in the synthetic resin, preferably between 2% and 5% by weight.

In the examples, percentages are by weight percentages unless otherwise indicated.

Example I

a) 200 ml of diethyl ether, 60.6 g of 67% sodium salt of α, α'-bis-hydroperoxide-1,3-diisopropylbenzene, 51 g of 99% cyclopentanone and 20 g of anhydrous calcium chloride were ground in a stirred flask 20. cooled to temperatures between -15 ° and -10 ° C, and 60 g of 36% HCl was slowly added over 20 minutes. The mixture was stirred at -5 ° C for an additional 1 hour, and the ethereal solution was then washed with water and dried over anhydrous sodium sulfate.

The α-af-bis (1-hydroxy-cyclopentylperoxy) -1,3-diisopropylbenzene thus obtained, of which 53 g was obtained, had an purity of 98% according to iodometric titration. The decomposition temperature was 45 ° C, and there was a half-life of 30 minutes at 98 ° C; a 10% solution in toluene showed no deterioration after 80 hours at 40 ° C. Elemental Analysis: C-66.4% and H = 8.2%; calculated: C = 66.98% and H = 8.69%.

B) In a flask equipped with a stirrer, 53 g of a), α, a'-bis (1-hydroxycyclopentylperoxy) - 1,3-diisopropylbenzene in 200 ml of diethyl ether, 44 g of 80% t-butyl-8105711-5 were obtained.

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hydroperoxide and 40 g of ground anhydrous calcium chloride cooled to -10 ° C, and 20 g of 30 Z hydrochloric acid was added over 5 minutes. The temperature was allowed to come to 0 ° C, and the solution was stirred at 0 ° G for 1 hour. Then the ethereal solution was washed with water, with 5 Z NaOH solution, and again with water. Then, the solvent was expelled under vacuum at 30 ° C to yield 69 g of a product identified as α, α'-bis (1-t-butylperoxycyclopentyl-peroxy) -1,3-diisopropylbenzene.

This material had a decomposition temperature of 114 ° C, and a half-life of 30 minutes at 123 ° C.

According to iodometric titration, there was a purity of 99 Z; 25 d ^ * 0.945; n ^ = 1.447. Elemental analysis: C 66.5% and H = 9.4 Z; calculated: C - 66.88% and H = 9.36%.

Example II

of a) Flask provided in a stirrer, 300 ml diethyl ether, 41.8 g 97.3 Z α, α'-bis-hydroperoxydo-1,4-diisopropylbenzene, 37.8 g 98 Z 4-t-butylcyelohexanone and 18 g ground anhydrous calcium chloride cooled to 0 ° C, and 24 g of 36% HCL was added over 20 minutes. The temperature was kept at 0 ° C for 1 hour with stirring. Then the ethereal solution was washed with water and concentrated in vacuo avoiding complete evaporation of the ether. There was thus obtained 66 g of a, a'-bis (1-hydro2Cy-4-t-butylcyclohexylperoxy) -1,4-25 diisopropylbenzene as a solution ready for the next preparation step. A sample of this, according to iodometric titration, had a purity of 98.5 Z, a decomposition temperature of 62 ° C and a half-life of 30 minutes at 112 ° C. Elemental Analysis: C = 70.4% and H = 10.1%; 30 calculated: C = 71.87 Z and H * 10.18 Z.

b) 150 g of an ethereal solution of the 66 g of α, αT-bis (1-hydroxy-4-t-butylcyclohexylperoxy) -1,4-diisopropylbenzene, 44 g of 80 Z in a flask equipped with a stirrer t-butyl hydroperoxide and 42 g of ground water-free calcium chloride cooled to -5 ° C and 30 g of 36 Z HCl was added over 5 minutes. The solution was stirred for another hour, 810571! - 6 - ensuring that the temperature did not rise above 0 ° C. Then the ether phase was washed with water, with 5% NaOH, and again with water. Then, the solvent was removed under vacuum at 30 ° C, yielding 76 g of residue, identified as a, a'-bis (1-butylperoxy-4-t-butylcyclohexylperoxy) -1,4-diisopropylbenzene, melting point 32- 34oC. According to iodometric titration, this was 99.8% pure. It had a decomposition temperature of 109 ° C, and a half-life of 30 minutes at 121 ° C. Elemental-10 analysis: C = 69.6% and H * 10.5%; calculated C = 70.75% and H * 10.40%.

Example III

a) 200 ml of benzene, 81 g of 67% sodium salt of α, α'-bis-hydroperoxydo-1,3-diisopropylbenzene, 33.5 g of 99% cyclohexanone and 25 g of ground anhydrous calcium chloride were placed in a stirred flask cooled to -10 ° C and 80 g of 36% HCl was added over 30 minutes. The mixture was stirred at -5 ° C for an additional 1 hour, then washed with water, and dried over anhydrous sodium sulfate.

Thus, a solution was obtained containing 71 g of α, αT-bis (1-hydroxycyclohexylperoxy) -1,3-diisopropylbenzene. According to iodometric titration, a sample evaporated to dryness thereof had a purity of 98%, a decomposition temperature of 55 ° C, and a half-life of 30 minutes, at 115 ° C. Elemental Analysis: C = 68.0%, H = 9.0%; calculated: C = 68.22% and H = 9.07%.

b) In a flask equipped with a stirrer, the 71 g of α, αT-bis (1-hydroxycyclohexy1-peroxy) -1,3-diisopropylbenzene in 200 ml of benzene obtained in Example 2 were obtained, 58 g of 80% t -butyl hydroperoxide and 45 g of ground anhydrous calcium chloride cooled to -10 ° C and 27 g of 36% hydrochloric acid was added over 5 minutes. The solution was stirred for an additional hour at temperatures between -5 ° and 0 ° C. Then the organic phase was washed with water, with 5% NaOH, and again with water. The benzene solution was then filtered over a mixture of anhydrous sodium sulfate and "Celite", and the dissolved 8105711% -7 agent was removed under vacuum at 30 ° C. This gave 91 g of product, which was identified as α, α'-bis- (1-t-butylperoxycyclohexylperoxy) -1,3-diisopropylbenzene, with d = 0.940 and = 1.452. Iodometric titration showed a purity of 98.5%. The decomposition temperature was 113 ° C, and there was a half-life of 31 minutes at 135 ° C. Elemental analysis: G67.5 and H = 9.6%; calculated: C = 67.81% and H = 9.6%.

Example IV

A) 300 ml of benzene, 65.4 g of 95% c ^ a'-bis-hydroperoxydo-1,4-diisopropylbenzene, 50 g of cyclododecanone and 50 g of ground anhydrous calcium chloride were added to -10 ° C in a flask equipped with a stirrer. cooled, and 60 g of 36% hydrochloric acid was added over 25 minutes. Stirring was continued for 1 hour at 15 + 5 ° C, and the benzene solution was then washed with water and dried over anhydrous sodium sulfate.

There was thus obtained 80 ga, a'-bis (1-hydroxycyclo-dodecylperoxy) -1,4-diisopropylbenzene, by iodometric titration for 98% pure, with a decomposition temperature of 59 ° C, with a half-life of 30 minutes at I14 ° C. Elemental analysis: G = 73.3% and Ii = 10.3%; calculated: C 73.17% and H = 10.58%.

b) In a flask equipped with a stirrer, the 80 g of α, αT-bis (1-hydroxycyclo-25 dodecylperoxy) -1,4-diisopropylbenzene in 300 ml of benzene, 66.7 g of 66.7% t were obtained in a). -butyl hydroperoxide and 40 g of ground anhydrous calcium chloride cooled to 0 ° C, and 5 g of 36% hydrochloric acid was added over 10 minutes. The temperature was allowed to rise to + 5 ° C, and the mixture was stirred at this temperature for 1 hour. Then the benzene phase was washed with water, with 5%

NaOH, and again with water.

The solvent was removed in vacuo at 40 ° C to give 48 g of a pale yellow residue, identified as α, ar-bis (1-butylperoxycyclododecyl-1-peroxy) -1,4-diisopropylbenzene, with n ^ = 1, 4580, a decomposition temperature of 109 ° C and a half-life of 30 minutes. 8105711-8 ° C at 120 ° C. According to iodometric titration, it was 99% pure. Elemental Analysis: C = 70.2% and H * 10.9%; calculated: C = 71.89% and H = 10.7%.

Example V

5a) In a stirred flask, 50 ml of benzene, 50 ml of diethyl ether, 21.4 g of 67% sodium salt of α, α'-bishydroperoxydo-1,3-diisopropylbenzene, 19.3 g of 4-t-butylcyclohexanone and 10 g of ground anhydrous calcium chloride was cooled, and 20 g of 36% 10 hydrochloric acid was added dropwise over 20 minutes. Then the mixture was stirred at -5 ° C for 1 more hour. The organic solution was washed with water and dried over sodium sulfate.

There was thus obtained 32 g of product, which was kept in solution, identified as otja-O-hydroxy-4-t-butylcyclohexylperoxy) -1,3-diisopropylbenzene.

According to iodometric titration, a sample evaporated to dryness had a purity of 95%, a decomposition temperature of 78 ° C and a half-life of 30 minutes at 110 ° C. Elemental Analysis: C = 71.3% and H * 10.0%; calculated: 20 C = 71.87% and H - 10.18%.

b) In a flask equipped with a stirrer, the 32 g of α, α'-bis (1-hydroxy-t-butylcyclohexylperoxy) -1,3-diisopropylbenzene in 50 ml of benzene and 50 ml of ether, 15 g of ether, obtained in a) were obtained. g of anhydrous calcium chloride and 43.9 g of 83.4% cumene-25 hydroperoxide cooled to -15 ° C, and 10 g of 36% hydrochloric acid was added over 10 minutes. Due to the heat development, the temperature rose to -5 ° C, and the mixture was stirred at -5 ° -0 ° C for 1 more hour. The organic phase was washed with water, with 5% NaOH, and again with water until neutral.

The solvent was removed under vacuum at 50 ° C, leaving a somewhat oily residue, identified as α, α1 -b is (1-cumylperoxy-4-t-buty1-20 cyclohexylperoxy) -1,3-diisopropylbenzene, with n ^ = 1.4985, a decomposition temperature of 114 ° C and a half-life of 35 minutes at 125 ° C. Iodometric titration shows that the purity was 90%. Elemental analysis: C = 75.1% and H - 8.5%; 8105711-9 calculated: C 74.4% and H 8.52%.

Example VI

Four comparative vulcanization tests were carried out with an ethylene-propylene copolymer, with 5 as vulcanizing agents, respectively α, a'-bis (1-t-butyl-peroxycyclopentylperoxy) -!, 3-diisopropylbenzene (A), a, a * -bis- (1-t-butylperoxy-4-t-butylcyclohexy Iperoxy) -1,4-diisopropylbenzene (B), a, ar-bis (It-butylperoxycyclohexylperoxy) -1,3-diisopropylbenzene (C), and for comparison also the α, α-bis-10 / α- (t-butylperoxy) isopropylperoxy-1,4-diisopropylbenzene (D).

These vulcanizations were performed at 177 ° C, with different durations, and were then determined using a Monsanto TM-10 rheometer. The vulcanized samples consisted of 100 parts of ethylene-propylene-co-15 polymer, 50 parts of carbon black, 3 parts of zinc oxide, 0.32 parts of sulfur and 0.01 mole of peroxide.

Thus, per 100 g of ethylene-propylene copolymer were used: 5.38 g of A, 6.79 g of B, 5.66 g of C and 2.70 g of D; the vulcanization times required with this were 5 minutes, 4 minutes, 5 minutes, 6 minutes and 14 minutes, respectively.

Moreover, with said peroxides, five vulcanization tests were each conducted at 150 ° C, with vulcanization times between 5 minutes and 60 minutes, and in comparison also vulcanization with dicumyl peroxide for 25 minutes at 165 ° C (which are the optimal conditions for the latter). The compositions of these vulcanized blends, as well as the amounts of peroxides used, were also 0.01 gmoles per 100 g of ethylene-propylene copolymer.

Table A lists the mechanical properties of the vulcanized products thus obtained. From this table it appears that, when using peroxides according to the invention, vulcanization is possible already at low temperatures, and yet at high speeds, whereby products are obtained with better mechanical properties than when using dicumyl peroxide for vulcanization.

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Example VII

Four comparative crosslinking tests were performed with low density polyethylene. Either no peroxide or α, α'-bis (1-t-butylperoxycyclopentyl-5-peroxy) -!, 3-diisopropylbenzene (A), a, a'-bis (1-butylperoxy-4-t-butylcyclohexylperoxy) - 1,4-diisopropylbenzene (B) and α, α-bis- / a- (t-butylperoxy) -1 sopropyl peroxy / -1,4-diisopropylbenzene (D) are used. To this end, heating was carried out at 145 ° C for 20 minutes, either without or with 0.01 g mol peroxide per 100 g polyethylene.

Table B shows some mechanical properties of the crosslinked synthetic resins thus obtained. The peroxides according to the invention advantageously differ from the known peroxide.

Table B also shows the degree of swelling of the resulting cross-linked synthetic resins. By "swelling degree", the volume of solvent absorbed by one volume unit of cross-linked polyethylene is determined by immersing a sample of 0.2 g of cross-linked polyethylene in 100 ml of xylene in a small basket for 21 hours. at 80 ° C, stabilized with 0.1 g of 4,4-thiobis (3-methyl-6-t-butylphenol). The degree of swelling is calculated using the following formula: 1.07. - + 1 * c 25 where a is the weight of the sample after 21 hours in xylene at 80 ° C, where b is the weight of the sample before the test, and where c is the weight of the sample after drying at the end of the test, 1.07 being the quotient of the density of polyethylene at 80 ° C and the density of xylene at 80 ° C.

8105711% X.

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Table Β

Cross-linking tests (20 min. At 145 ° C)

Peroxide Mechanical properties of the cross-linked synthetic resins

Yield strength Tensile strength Elongation at break Degree of kg / cm2 kg / cm% swelling

None 57.8 73 150 A 55 150 570 16.5 B 52.7 137 260 20.2 D 57.0 145 450 59.4 8105711

Claims (1)

s -13- Process for the preparation of var. bonds of formula 1, wherein X is an arylendialkyl-5 group and R 1 is a tertiary alkyl group, characterized in that compounds of formula 1, wherein R 1 and R 1 together with the connecting carbon atom form a cycloalkylidene group, are prepared by a cycloalkanone according to formula 3 in the presence of an acid and a dewatering agent at a temperature between -30 ° and + 80 ° C with a bis-hydroperoxide according to the general formula Η00-Χ-00Η (with a molar ratio to the cycloalkanone between 1: 1,2 and 1:10), wherein X has the aforementioned meaning, and the compound of formula 4 thus formed in the presence of an acid and a dewatering agent with a tertiary alkyl hydroperoxide of the formula R 1 -OH ( reacting with a molar ratio to the compound of formula 2 between 2: 1 and 10: 1), wherein Rg has the aforementioned meaning. 20 8105711