MXPA98001594A - Mixtures of liquid multi-components of azodinitr - Google Patents

Abstract

An azodinitrile composition comprising a mixture of at least six different azodinitriles of the formula (I) is described, wherein R1, R2, R3 and R4 are each independently aliphatic, acyclic hydrocarbon radicals of 1-9 carbon atoms, The mixture has a freezing point of a maximum of 25 ° C and a process for its preparation

Description

MIXTURES OF LIQUID MOLECULES OF AZODINITRIL FIELD OF THE INVENTION The present invention relates to multicomponent mixtures of azodinitrile which are liquids below 25 ° C to be used as initiators of the polymerization of free radicals in various polymerization reactions.

BACKGROUND OF THE INVENTION The azodinitrile compounds represent an important class of free radical initiators which are used in a variety of industrial applications. Examples of such applications include: vmyl polymerizations, graft polymerizations, halogenacior.es and blowing agents. With respect to peroxide initiators, the behavior of decomposition consisting of the display of azodinitrii, less color formation and a greater degree of security. The azodinitrile compounds can be either symmetric or asymmetric around the azo bond. The symmetric azo primers of interest REF: 26711 commercial are generally solid and have low solubility of the medium in organic solvents. Asymmetric azo primers, in contrast, are often low melting solids with high solubilities in organic solvents. Polymer manufacturers have long sought liquid azodinitrile initiators to eliminate the problems associated with commercially available solid azodinites such as powders, ergonomic and inability to aggregate them through screw feeders. A liquid azodinitrile compound or mixture of compounds with a melting point of 0 ° C or less, preferably -15 ° C, should be ideal for commercial applications. In addition, a liquid azo mixture, which facilitates polymerizations using little or no solvent for the volatile, lower organic compound coatings is desirable. U.S. Patent 3,987,025 to Moore issued October 19, 1976, discloses liquid mixtures of symmetrical and asymmetric azodinitrile compounds with a maximum freezing point of 25 ° C. The initial aminonitriles are limited to two and for those that have unbranched hydrocarbon groups. This patent also suggests that it is possible to prepare mixtures of liquid azodinitrile when more than two starting materials of aminonitrile are used, and that the mixtures of liquid azodinitrile will be highly approved as the number of inonitriles, increases by more than two. However, not all mixtures prepared using more than two aminonitriles are liquid at 25 ° C, and Moore does not teach any such mixtures. Many synthetic routes are known during the preparation of azodinitriles by means of the reaction of a ketone with a hydrazine compound to generate a hydrazo compound, which is then oxidized to azodiniyl. A second approach reacts a cyanohydrin of a ketone with ammonia to form an aminonitrile and in an oxidative form which couples the aminonitrile to form an azodinitrile. The aliphatic azodinitics can be prepared by reacting a metal hypochlorite with an aminonitrile in water containing a surfactant. These syntheses do not specifically address how to obtain mixtures prepared from more than two aminonitriles, which are liquids at low temperatures. Such mixtures are desirable for use as free radical initiators in industrial applications.

BRIEF DESCRIPTION OF THE INVENTION The present invention comprises a composition of azodinitrile and a process for the preparation comprising a mixture of at least six different azodinitriles of the formula I R-.

R2-C-N = N-C-R4 CN CN where Ri / 2? R3 and R are each independently selected from the group consisting of aliphatic hydrocarbon radicals, acyclics of 1-9 carbon atoms, preferably 4-9 carbon atoms, the mixture has a freezing point of a maximum of 25 °. C. Preferably the compositions are liquid and have a maximum freezing point of 0 ° C to -15 ° C.

The present invention further comprises a process for the preparation of azodinitrile mixtures comprising reacting three or more different aminonitriles of the formula R2-C-NH2 CN wherein Ri and R2 are each independently selected from the group consisting of aliphatic hydrocarbon radicals, acyclics of 1-9 carbon atoms, with 5% to 15% by weight based on the reaction mixture of a metal hypochlorite , M (Ocl) x, in which M is selected from the group consisting of sodium, potassium or calcium, and x is the valence of M, in an aqueous medium in the presence of 0.25 a % by weight based on the weight of aminonitrile of an active surface compound or mixtures thereof having a hydrophilic-lipophilic moiety of 8 to 35 at a temperature of -10 ° C to 30 ° C, the metal hypochlorite and alpha-aminonitrile are present in an equivalent ratio of 1: 1 to 2: 1 of hypochlorite to aminonitrile and which recover from the reaction product a mixture of aliphatic azodinitrile compounds of the formula R2-C-N = N-C-R < CN CN wherein Ri, R2, R3 and R4 are each independently selected from the group consisting of aliphatic hydrocarbon radicals, acyclics of 1-9 carbon atoms.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 depicts a phase diagram showing the concentration ranges of aminonitrile reagents as detailed in Example 1, which produces liquid mixtures at -15 ° C for a mixture of 2,2'-azobis (2-methyl) -butanonitrile, 2, 2'-azobis (2-me-il-pentanenitrile, 2,2'-azobis (2-methyl-heptanonitrile, 2 - [(1-cyano-1-meth i 1-propyl) azo] -2-methyl -heptanonitrile, 2- [(1-cyano-l-methylbutyl) azo] -2-methyl-heptanonitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-methyl-pentanenitrile. Figure 2 depicts an in-phase diagram showing the concentration of aminonitrile reagents which produce liquid mixtures of azodinitriles at 20 ° C for the same product mixture as defined for Figure 1. Figure 3 represents an in-phase diagram that shows the concentration ranges of aminonitrile reagents as detailed in Example 2, which produces liquid mixtures at -15 ° C for a mixture of 2,2'-azobis (2-methyl-butanonitrile, 2, 2'-azobis (2-methyl-pentanenitrile, 2, 2'-azobis (2-methyl-octanenitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-methyl-octanenitrile, 2- [(1-cyano-1-met i lbutil) azo] -2-methyl-octanenitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-methyl-pentanenitrile.

Figure 4 depicts a phase diagram showing the concentration ranges of aminonitrile reagents as detailed in Example 3, which produces liquid mixtures at 7 ° C for a mixture of 2,2'-azobis (2-methyl- butanonitrile, 2, 2'-azobis (2-methyl-heptanonitrile, 2,2'-azobis (2-methyl-octanenitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-methyl-octanenitrile, 2 - [(1-cyano-l-methylhexyl) azo] -2-methyl-octanonitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-methyl-heptanonitrile.

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises a mixture of azodinitrile compounds such that the liquid performance is obtained at temperatures at or below 25 ° C. Preferably the mixtures have a maximum freezing point of 0 ° C, and more preferably -15 ° C. The compositions contain both symmetric or asymmetric azodinitrile compounds. The compositions of the present invention are prepared from three or more aminonitriles. The mixture of the particular azodinitrile product obtained depends on the initial aminonitrile materials used. Starting with three different aminonitriles R ^ a) R2-C-NH2 (b) R4-C-NH2 (c) R6-C-NH2 CN CN CN wherein Ri, R2, R3, R4, R5 and Re are each independently selected from the group consisting of aliphatic hydrocarbon radicals, acyclics of 1-9 carbon atoms resulting in a mixture of azodinitrile comprising symmetric products such as R2-C-N = N-C-R2, R4-C-N = N-C-R4 R6-C-N = N-C-R6, CN CN CN CN CN CN and asymmetric products such as Ri R -. R- R < R2-C-N = N-C-R4, R2-C-N = N-C-R6 R4-C-N = N-C-R6, CN CN CN CN CN CN This can be easily determined that when the start with three different aminonitriles will be three different symmetrical azodynitriles, and three different asymmetric azodinitriles. When the start with four different aminotritriles will be four different symmetrical azodinitriles, and six different asymmetric azodinitriles. In the general case when the start with n different aminonitriles will be n different symmetric azodinitriles and n! / 2 (n-2)! Different asymmetric azodinitriles in the resulting product. The aliphatic, acyclic hydrocarbon radicals suitable for Ri, R 2, R 3, R 4, R 5 and R include, for example, methylbutyrole, methopentane, methyloheptane, methyloctane, ethylbutane, cyanomethylpropyl, cyanomethylbutyl and cyanodimethylbutyl. The preferred azodinitrile compositions of the present invention are liquid to and have a maximum freezing point of 25 ° C and include mixture A as follows: A. 2,2'-azobis (2-methyl-butanonitrile, 2, 2'-azobis (2-methyl-pentanenitrile, 2,2'-azobis (2-ethyl-butanonitrile, 2- [(1-cyano-1) -methylpropyl) azo] -2-methyl-pentanenitrile, 2- [(1-cyano-l-ethylpropyl) azo] -2-methyl-pentanenitrile, 2- [(1-cyano-1-methylpropyl) azo] -2- ethyl-butanonitrile The following mixture B of the present invention having a maximum freezing point of 7 ° CB 2,2'-azobis (2-methyl-butanonitrile, 2,2'-azobis (2-methyl- heptanonitrile, 2,2'-azobis (2-methyl-octanonitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-met-il-octanoni trilo, 2- [(1-cyano-l-methylhexyl) azo] -2-methyl-octanoni-ryl, 2 - [(l-cyano-l-methylpropyl) azo] -2-methyl-heptanonitrile The most preferred azodinitrile compositions of the present invention are liquid to and have a maximum freezing point of 0 ° C and include mixtures C and D as follows: C. 2,2'-azobis (2-methyl-pentanenitrile, 2,2'-azobis (2-ethyl-butanonitrile, 2,2'-azobis (2-methyl-heptanonitrile, 2- [(1-cyano- 1 -met ilbut il) azo] -2-methyl-heptanonitrile, 2- [(1-cyano-l-ethylpropyl) azo] -2-methyl-heptanonitrile, 2- [(1-cyano-l-ethylpropyl) azo] - 2-methyl-pentanenitrile, D. 2, 2'-azobis (2-methyl-butanonitri-lo, 2,2'-azobis (2-methyl-pentanenitrile, 2,2'-azobis (2,4-dimethyl) pentanonitrile, 2, 2'-azobis (2-methyl-heptanonitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-methyl-heptanonitrile, 2- [(1-cyano-l-methylbutyl) azo] -2-methyl-heptanonitrile, 2- [(1-cyano-l, 3-dimethylbutyl) azo] -2-methyl-heptanonitrile, 2 - [(l-cyano-l-methylbutyl) azo] -2, 4 -dimet il-pentanenitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-methyl-pentanenitrile, 2- [(1-cyano-l-methylpropyl) azo] -2,4-dimethyl-pentanenitrile.

More particularly preferred are the azodinitrile compositions which are liquid and have a maximum freezing point of -15 ° C and include the following mixtures E, F and G: E. 2, 2'-azobis (2-methyl-butanonitrile, 2, 2'-azobis (2-methyl-pentanenitrile, 2,2'-azobis (2-methyl-heptanonitrile, 2- [(1-cyano-1-methyl-ylpropyl) -zo] -2-methyl-heptanonitrile, 2- [(1-cyano-l-methylbutyl) azo] -2-methyl-heptanonitrile, 2- [(1-cyano-1-methyl-ylpropyl) azo] -2-methyl-pentanoni-ryl, F. 2,2'-azobis (2-methyl-butanonitrile, 2,2'-azobis (2-methyl-pentanenitrile, 2,2'-azobis (2-methyl-octanenitrile, 2- [(1-cyano-1-methyl-ylpropyl) azo] -2 -methyl-octanonityl, 2- [(1-cyano-l-methylbityl) azo] -2-methyl-octanonitrile, 2- [(1-cyano-1-methyl-propyl) -zo] -2-methyl-pentanenitrile, G. 2,2'-azobis (2-methyl-butanonitrile, 2,2'-azobis (2-methyl-pentanenitrile, 2,2'-azobis (2-yl-butanonitrile, 2,2'-azobis (2 -methyl-heptane-nitrile, 2- [(1-cyano-1-methyl-ylpropyl) azo] -2 -methyl-heptanonitrile, 2- [(1-cyano-l-methylbutyl) azo] -2-methyl-heptanonitrile, 2- [(1-cyano-l-ethylpropyl) azo] -2-methyl-heptanonitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-methyl-pentanenitrile, 2 - [(l-cyano-l-ethylpropyl) azo] -2-methyl-pentanenitrile, 2- [(1 - cyano-1-methylapropyl) azo] -2-ethyl-butanonitrile. The ratio of initial aminonitriles can affect the physical phase of the mixture of the resulting product. The figure represents a phase diagram at -15 ° C for the particularly preferred composition E above. As detailed in Example 1, this composition is prepared from 2-amino-2-methylbutyronitrile (Component A), 2-amino-2-methylpentanenitrile (Component B) and 2-amino-2-methylheptanonit ryl ( Component C). The phase diagram of Figure 1 shows the percentages of each initial aminonitrile, which when reacted, results in a product composition which is liquid at -15 ° C. The liquid compositions correspond approximately to the line area. These correspond to 30-50% by weight of component A, 5-25% by weight of component B and 30-55% by weight of component C. Figure 2 represents a phase diagram at 20 ° C for those same components A , B and C. The liquid compositions correspond approximately to the line area, which correlate with 20-55% by weight of component A, 5-30% by weight of component B and 30-55% by weight of component C .. They also show that there are three data points (0) which exhibit the partial liquid behavior. For these compositions removed from solids, such as by means of filtration, will result in the desired liquid composition. Figure 3 represents a phase diagram at -15 ° C for the composition F defined in the above. As detailed in Example 2, this composition is prepared from 2-amino-2-met ilbut ironit ril (Component A), 2-amino-2-met ilpentanonit ril (Component B) and 2-amino-2-metiloctanonit ryl (Component D). The phase diagram of Figure 3 shows the percentages of each initial aminonitrile, which when reacted, result in a product composition which is 100% liquid, or approximately 50% liquid, or solid at -15 ° C. The circles represent 100% liquid, the circles with a line through them represent approximately 50% liquid, and the solid black circles represent 100% solid. Figure 4 represents a phase diagram at 7 ° C for composition B defined in the above, as detailed in Example 3. This composition is prepared from 2-amino-2-met ilbut ironitrile (Component A), 2-amino-2-methoheptanonitrile (Component E) and 2-amino-2-metiloctanonityl (Component D). This phase diagram shows the percentages of each initial aminonitrile, which when reacted, result in a product composition which is 100% liquid (circles), approximately 50% liquid (circles with lines through them) and solid (black circles). The liquid azodinitrile mixtures of this invention are useful in producing ethylene copolymers. High pressure copolymerizations of ethylene and vinyl acetate, methyl methacrylate, ethyl acrylate, acyclic and matacrylic acids and salts, vinyl chloride, acrylonitrile, olefins such as propylene, butene-1 and butadiene, dibutyl maleate, monoxide carbon and the like can be carried out easily and efficiently using the azodinitrile mixtures of this invention as polymerization initiators. These novel compositions are initiators for the polymerization or copolymerization of other unsaturated monomers such as alkenes, vinyl halides, vinyl esters, vinylidene halides, vinyl cyanides and aromatic alkenyl as well as curing agents for polyester resins, initiators for radicals free that initiate chemical reactions, blowing agents to produce foamed polymer and plastic and selective oxidizing agents. Illustrative polymerizable monomers other than ethylene and ethylene comonomers are vinyl chloride, vinylidene chloride, vinyl acetate, vinylpyridine, vinyl pyrrolidone, vinyl carbazole, butadiene, isoprene, acrylonitrile, acyclic acid, esters of acyclic acid, methacrylic acid, esters of methacrylic acid, styrene, chlorostyrene and methylesters. The liquid azodinitrile mixtures of this invention are concentrated fluids and are useful in full strength, where they are desirable, convenient or necessary. Any organic solvent which is liquid under the reaction conditions and inert with respect to the azodinitriles of this invention can be used as a diluent for the azodinitrile mixtures described herein. Some such suitable solvents include, for example, suitable alcohols, aliphatic hydrocarbons, esters, glycol ethers, ketones, aliphatic petroleum naphthas, aromatic hydrocarbons, chlorinated aliphatic hydrocarbons, chlorinated aromatic hydrocarbons, amides, nitriles, or mixtures thereof. The azodinitriles of the present invention are synthesized in accordance with the process of US Pat. No. 4,028,345, the teachings of which are incorporated herein by reference. At least three aminonitriles are reacted with sodium hypochlorite solution and quaternary amine salts. The excess hypochlorite is neutralized with sodium bisulfite and the resulting liquid azo mixture is separated from the aqueous phase, washed with bicarbonate and dried under vacuum.

In the process of the present invention, three molecules of an amino compound are selected from the group consisting of R-. « a) R2-C-NH2 (b) R4-C-NH2 (c) R6-C-NH2 CN CN CN wherein Ri, R2, R3, R4, R5 and Rs are each independently an aliphatic, acyclic hydrocarbon radical of 1-9 carbon atoms, are reacted to form the azodinitrile of the present invention. The reaction is achieved in an aqueous medium with a metal hypochlorite represented by the formula M (0C1) X / in which M is selected from sodium; potassium and calcium and x is the valence of the M ion, and an active surface compound selected from the group consisting of anionic, cationic, nonionic, amphoteric ion and surfactant surface active agents or mixture. The equivalent ratio of hypochlorite to aminonitrile is not critical. However, the equivalent ratios below 1: 1 of hypochlorite to aminonitrile yield is less desirable. At equivalent ratios above 2: 1 are not advantageous. Generally, the equivalent ratio of 1: 1 to 2: 1 will give high yields through the ratio of 1.2: 1 to 1.8: 1, it is preferably due to the especially high yields that result. The equivalent ratio referred to herein is defined as the metal hypochlorite equivalent per mole of aminonitrile. An equivalent of metal hypochlorite is one mole of hypochlorite divided by the valence of the metal. An equivalent of aminonitrile is the same as the molar amount of aminonitrile. The amino compounds used as starting materials can be selected from the given formulas represented in the above (a) (b) and (c) or combinations thereof. Amino compounds can be prepared by methods known in the art, for example, by the method described by Anderson in U.S. Patent 2,711,405. A process that can be used to obtain amino compounds that involve loading an appropriate ketone into a pressure vessel in line with platinum and cooling it to acetone temperature with dry ice and then adding 5-10 grams of ammonia. The hydrogen cyanide is then introduced in portions in an amount equimolar to that of the ketone. The reaction vessel is heated to room temperature and pressurized to 34.5 x 104 Pa (50 psig) with ammonia, heated to 40 ° C and stopped at 40 ° C and 34.5 x 104 Pa (50 psig) for 8 hours and finally it is cooled and the product is discharged from the container. The hydrochloride used in the present invention is a metal hydrochlorite represented by the formula M (0C1) X, where M is selected from sodium, potassium and calcium and x is the valence of M. For reasons of convenience and economy, sodium hypochlorite It is the preferred hypochlorite. Sodium hypochlorite can be prepared by passing chlorine gas into a sodium hydroxide solution at approximately 9 ° C or it can be commercially purchased. Other hypocloptos can be analogously prepared. The surface active compounds used in the present invention are defined as any compound or mixture of compounds that affect the surface tension when mixed with water and do not adversely affect their properties if reacted with the hypochlorite, aminonitrile, intermediate of chloramine 'or the final product of the present invention. The inclusion of a surfactant in the process of aminonitriles that are reacted to give an azodinitrile with hypochlorite allowing the reaction to be processed in the strictly aqueous medium. The surfactants during the preparation of emulsions are described by Paul Becher in "Emulsions, Theory and Practice" ACS Monograph No. 162, 1965. On pages 232-255. Becher describes the importance of the Hydrophilic-Lipophilic Balance of a surfactant (HLB) on its ability to serve as an emulsifying or emulsifying agent in a particular application. The HLB numbers which have been assigned to indicate the balance of many surfactants in their affinity for water (hydrophilic) or non-polar organic liquids (lipophilic). A high HLB number indicates high water solubility and low organic solubility, a low number indicates a high organic solubility and low water solubility. The azodinitriles of the present invention can generally be produced with surfactants or mixtures thereof within the range of about 8.0 to about 35.0 HLB in the range. The surfactants or surface active agents useful in the present invention may be a mixture of surfactants or surface active agents. Thus, in mixtures of surfactant, a component of the mixture may have a HLB number outside the range described herein as long as the HLB of the mixture is within the range. The system of atmospheric pressure is totally aqueous, not requiring organic solvent to be present as a promoter or co-solvent with water. The surfactant is mixed with water such as sodium hypochlorite or other metal hypochlorite and the aminonitrile is added with sufficient cooling to handle the heat load. During the reaction period, it is necessary to add an agent to destroy the residual sodium hypochlorite, chloramines and other oxidation impurities and thus giving a clean product. Sodium bisulfite serves for this purpose, as well as gaseous or liquid S02. Acid such as hydrochloric or sulfuric is introduced during the elaboration of the product to increase the activity of sodium bisulfite converting it in part or all to sulfur dioxide, a potent reducing agent. Other inorganic salts can be used.

Any concentration of sodium hypochlorite less than about 16% may be used, but 5-15% is preferred. With less than 5%, product yields tend to fall. However, calcium hypochlorite, which is available as a 100% active material, is diluted to reach the preferred 5-15% range. Potassium hypochlorite solutions of the above concentration may also be preferred. The time required to complete the reaction depends on the temperature. A typical temperature for the reaction is -10 ° C to 30 ° C. In the preferred temperature range of 5 ° -15 ° C, the reaction takes from about 10 minutes to 30 minutes. At a temperature of -5 ° C, the reaction will be taken for 1 hour. At 30 ° C, the reaction can be complete in 5 minutes. The time required for the reaction for a specific product at a specific temperature and the batch size can be easily determined. The azodinitrile compositions which exist in solid and liquid phases simultaneously at a particular temperature can be filtered to remove the solids. The resulting filtrate should be suitable for use as a polymerization initiator in the same manner as the compositions of the present invention. The present invention is further illustrated by the following examples.

EXAMPLES For all examples, the percent solids are determined as follows. The samples will be. Place them in glass ampoules and store at recorded temperatures for at least 72 hours. The solids were visually estimated relative to the total amount of the sample present in the vial (ie, and the solid layer occupying a tenth of the vial is designated 10% solids).

EXAMPLE 1 To a 1.0-liter beaker equipped with a motor-driven Teflon-coated stirrer, thermocouple, 100-ml addition funnel, and placed in a dry ice-acetone cooling bath, 286.7 g (0.5665 moles) of sodium hypochlorite were added. at 14.71% over long with 1.54 g of dioctyl dimethyl ammonium chloride. The temperature is reduced to 7 ° C and a mixture of aminonitriles consisting of 20 g (0.20389 moles) of 2-amino-2-methylbutanonitrile (MEK), 10 g (0.0891 moles) of amino-2-methylpentanenitrile (MPK) and 20 g (0.1429 moles) of 2-amino-2-methylheptanonitrile (MAK) which have been sprayed in excess ammonia for one hour at 35 ° C, were added over a period of 50 minutes. After the addition, the temperature was held at 7 ° C for 30 minutes followed by neutralization of excess hypochlorite with 20 g of sodium bisulfite while the pH is maintained above 9 with the addition of 3.1 g of ION sodium hydroxide. The liquid organic layer is then separated from the more dense aqueous phase and subsequently washed with 5% sodium bicarbonate. After 2 additional washes and separations with deionized water, the unpurified product is dried under vacuum (10 mm Hg, 13.3 x 102 Pa) for 2 hours. The final purity by means of gas evolution and gas chromatography, 98%. Final performance of 91%. Liquid at -15 ° C. The product mixture contains: 2, 2'-azobis (2-methyl-butanonitrile, 2,2'-azobis (2-methyl-pentanenitrile, 2,2'-azobis (2-methyl-heptanonitrile, 2- [(1) -cyano-l-methylpropyl) azo] -2-methyl-heptanonitrile, 2- [(1-cyano-l-methylbutyl) azo] -2-methyl-heptanonitrile, 2- [(1-cyano-l-methylpropyl) azo] ] -2-methyl-pentanenitrile. % of MEK reagents 70 65 55 54 50 45 40 40 37 35 33 25 25 15 MPK 15 10 20 12 12.5 10 40 20 13 5 33 25 20 20 MAK 15 25 25 34 37.5 45 20 40 50 60 33 50 55 65 % Yield 82 76 82 90 39 91 87 91 93 91 90 87 88 93% Purity 94 97 97 98 93 95 96 96 91 90 96 95 94 88 Form S S S S L S L 3 S S S S This data is represented in Figure 1. S indicates solid, L indicates liquid, and 50% L indicates 50% liquid. The following examples are completed following the procedure given in Example 1, using the aminonitriles indicated in a percentage by weight of the base. The form is indicated using the abbreviations defined in the above.

EXAMPLE 2 % Reactive 2-Amino-2-methylbutyronitrile 33 40 20 40 50 25 25 2-Amino-2-methylpentanenitrile 33 20 40 40 25 50 25 2-Amino-2-methyloctanenitriio 33 40 40 20 25 25 50 % Yield 94.5 87.5 86.9 87.8 73 86.8 87 % Purity 96.3 96.0 99.6 92.0 97.3 96.9 99.2 Form S 50% L L S 50% S S This data is represented in Figure 3.

Product mixture: 2, 2'-azobis (2-methyl-butanonitrile, 2, 2'-azobis (2-methyl-pentanenitrile, 2, 2'-azobis (2-methyl-octanenitrile, 2- [(1-cyano - 1-methylpropyl) azo] -2-methyl-octanenitrile, 2- [(1-cyano-1-methylbutyl) azo] -2-methyl-octanenitrile, 2- [(1-cyano-1-methylapropyl) azo] -2-methyl-pentanenitrile.

EXAMPLE 3 % of Reagents 2-Amino-2-methylbutyronitrile 33 20 40 40 50 25 25 2-Amino-2-methylheptanonitrile 33 40 20 40 25 50 25 2-Amino-2-methyloctanenitrile 33 40 40 20 25 25 50 % of Performance 79 62.3 37.3 89.7 32.5 54.0 90.9 % Purity 94.8 98.13 39.4 99.9 99.9 98.1 98.3 Form 50% L 50% L S S This data is represented in Figure 4.

Product Mix: 2, 2'-azobis (2-methyl-butanonitrile, 2, 2'-azobis (2-methyl-heptanonitrile, 2, 2'-azobis (2-methyl-octanenitrile, 2- [(1-cyano) -l-methylpropyl) azo] -2-methyl-octanenitrile, 2- [(L-cyano-l-ethylhexyl) azo] -2-methyl-octanonitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-methyl-heptanonitrile.

EXAMPLE 4 Reagents 2-Amino-2-met ilbutironit ilo 333 2-Amino-2-methylpentanonit rile 33% 2-Amino-2-ethylbutyronitile rile 33% Yield = 88.3% Purity = 93.1% 33% solid at 25 ° C 100% solid at 0 ° C Product mixture: 2, 2'-azobis (2-methyl-butanonitrile, 2, 2'-azobis (2-methyl-pentanenitrile, 2,2'-azobis (2-eti-1-butanonitrile, 2- [(1- cyano-l-methylpropyl) azo] -2-methyl-pentanenitrile, 2- [(1-cyano-l-ethylpropyl) azo] -2-methyl-pentanenitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-ethyl-butanonitrile EXAMPLE 5 Reagents: 2-Amino-2-me ilbut ironitrile 21% 2-Amino-2,4-dimethylpentanoni rile 26% 2-Amino-2-methylpentanonitrile 24% 2-Amino-2-methylheptanonitrile 29% Performance = 95% Purity = 93% Liquid at 0 ° C 100% solids at -15 ° C Product Mix: 2, 2'-azobis (2-methyl-butanonitrile, 2,2'-azobis (2-methyl-pentanenitrile, 2,2'-azobis (2,4-dimethyl-pentanenitrile, 2, 2 ' -azobis (2-methyl-heptanonitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-methyl-heptanonitrile, 2- [(1-cyano-l-methylbutyl) azo] -2-methyl-heptanonitrile , 2- [(1-cyano-l, 3-dimethylbutyl) azo] -2-methyl-heptanonitrile, 2- [(1-cyano-l-methylbutyl) azo] -2,4-dimethyl-pentanenitrile, 2- [( 1-cyano-l-methylpropyl) azo] -2-methyl-pentanenitrile, 2- [(1-cyano-l-methylpropyl) azo] -2,4-dimethyl-pentanonityl.

EXAMPLE 6 Reagents: 2-Amino-2-methylpentanonitrile 21% 2-Am? No-2-me ilheptanonitrile 26% 2-Amino-2-metiloctanoni trilo 24% Performance = 99% Purity = 93% Liquid at 25 ° C 100% Solid at 0 ° C Product Mix: 2, 2'-azobis (2-methyl-pentanenitrile, 2,2'-azobis (2-methyl-heptanonitrile, 2, 2'-azobis (2-methyl-octanenitrile, 2- [(1-cyano) -l-methylbutyl) azo] -2-methyl-octanonitrile, 2- [(1-cyano-l-methylhexyl) azo] -2-methyl-octanonitrile, 2- [(1-cyano-1-methyl-ylbutyl) azo] ] -2-methyl-heptanonitrile EXAMPLE 7 2-Amino-2-methylbutyronitrile 25% 2-Amino-2-ethylbutanonitrile 25% 2-Amino-2-methylpentanonitrile 25% 2-Amino-2-methylheptanonit rile 25% Performance = 85% Purity = 97% Liquid at 25 ° C Liquid at -15 ° C Product Mix: 2, 2'-azobis (2-methyl-butanonitrile, 2,2'-azobis (2-methyl-pentanenitrile, 2,2'-azobis (2-ethyl-butanonitrile, 2, 2'-azobis ( 2-methyl-heptanonitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-methyl-heptanonitrile, 2- [(1-cyano-l-methylbutyl) azo] -2-methyl-heptanonitrile, 2- [(1-cyano-l-ethylpropyl) azo] -2-methyl-heptanonitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-methyl-pentanenitrile, 2- [(1-cyano-l-ethylpropyl) azo] -2-methyl-pentanenitrile, 2- [(1-cyano- l-methylpropyl) azo] -2-ethyl-butanonitrile.

COMPARATIVE EXAMPLE A Reactives: 2 -Amino- 2-me t i lbut i roni t r i lo 25% 2-Amino-2-methylpropanonitrile 25% 2 -Amino- 2-methylpentanonityl 25% 2-Amino-2-methylheptanonitrile 25% Yield = 56% Purity = 96%, 10% solids at 25 ° C 75% solids at 0 ° C 100% solids at -15 ° C Product Mix: 2, 2'-azobis (2-methyl-propanenitrile, 2,2'-azobis (2-methyl-butanonitrile, 2,2'-azobis (2-methyl-pentanenitrile, 2,2'-azobis ( 2-methyl-heptanonitrile, 2- [(1-cyano-l-methylethyl) azo] -2-methyl-heptanonitrile, 2- [(1-cyano-1-methyl-ylpropyl) azo] -2-methyl-heptanonitrile, 2- [(1-cyano-l-methylbutyl) azo] -2-methyl-heptanonitrile, 2- [(1-cyano-1-methyl-lethyl) azo] -2-methyl-pentanenitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-methyl-pentanenitrile, 2- [(1-cyano) -l-methylethyl) azo] -2-methyl-butanonitrile.

COMPARATIVE EXAMPLE B Reagents: 2 -Amino-2-met ilbut ironitrile 33% 1-aminocyclohexanecarbonitrile 33% 2-Am? No-2-methylheptanonitrile 33% Performance = 80% Purity = 96%, 20% solids at 25 ° C 60% solids at -15 ° C Product Mix: 2, 2'-azobis (2-methyl-butanonitrile, 1,1'-azobis-cyclohexanecarbonitrile, 2,2'-azobis (2-methyl-heptanonitrile, 2- [(cyanocyclohexane) azo] -2- methyl-heptanonitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-methyl-heptanonitrile, 2- [(1-cyano-l-methylpropyl) azo] -cyclohexane-carbonitrile.

COMPARATIVE EXAMPLE C Reagents: 2-Amino-2-met ilbutironit rilo 33% 1-aminocyclohexanecarbonitrile 33% 2-Am? No-2-methylpentanon? Trilo 33% Yield = 70% Purity = 94%, 30% solids at 25 ° C 100% solids at -15 ° C Product Mix: 2, 2'-azobis (2-methyl-butanonitrile, 1,1''-azobis-cyclohexanecarbonitrile, 2,2''-azobis (2-methyl-pentanenitrile, 2- [(1-cyano-l-methylpropyl ) azo] -cyclohexane-carbonitrile, 2- [(1-cyano-l-methylbutyl) azo] -cyclohexane-carbonitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-methyl-pentanenitrile. state that in relation to this date, the best method known by the applicant to carry out the aforementioned invention is that which is clear from the present description of the invention. Having described the invention as above, the content is claimed as property in the following:

Claims (8)

1. An azodinitrile composition characterized in that it comprises a mixture of at least six azodinitriles of different formula I R2-C-N = N-C-R¿ CN CN wherein Ri, R2 3 and 4 are each independently selected from the group consisting of aliphatic hydrocarbon radicals, acyclics of 1-9 carbon atoms, cyanomethylpropyl, cyanomethylbutyl and cyanodimetylbutyl, the mixture has a freezing point of a maximum of 25 ° C.

2. The composition according to claim 1, characterized in that it has a freezing point of a maximum of 0 ° C.

3. The composition according to claim 1, characterized in that it has a freezing point of a maximum of -15 ° C.

4. The composition according to claim 1, characterized in that RL, R2, R3 and R4 are each independently selected from the group consisting of methylbutyl, methylpentyl, methylheptyl, methyloctyl, ethylbutyl, cyanomethylpropyl, cyanomethylbutyl and cyanodimethylbutyl.

5. The composition according to claim 1, characterized in that it is selected from the group consisting of mixtures A and B: A. 2, 2'-azobis (2-methyl-1-butanonitrile, 2,2'-azobis (2-methyl) -pentanonitrile, 2, 2'-azobis (2-ethyl-butanonitrile, 2- [(1-cyano-l-methyl-ylpropyl) azo] -2-methyl-pentanenitrile, 2 - [(l-cyano-l-ethylpropyl)] azo] -2-methyl-pentanenitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-ethyl-butanonitrile, B. 2,2'-azobis (2-methyl-butanonitrile, 2,2'- azobis (2-methyl-heptanonitrile, 2, 2'-azobis (2-methyl-octanitrile, 2- [(l-cyano-l-methylpropyl) azo] -2-methyl-octanitrile, 2- [(1-cyano- l-methylhexyl) azo] -2-methyl-octanonitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-methyl-heptanonitrile.

6. The composition according to claim 2, characterized in that it is selected from the group consisting of mixtures C and D: C. 2,2'-azobis (2-methyl-pentanenitrile, 2,2'-azobis (2-ethyl-butanonitrile , 2, 2'-azobis (2-methyl-heptane-nitrile, 2 - [(l-cyano-l-methylbutyl) azo] -2-methyl-heptanonitrile, 2- [(l-cyano-l-ethylpropyl) azo] - 2-methyl-heptanonitrile, 2- [(1-cyano-l-ylpropyl) azo] -2-methyl-pentanonitrile, D. 2,2'-azobis (2-methyl-butanonitrile, 2, 2 '- azobis (2-methyl-pentanenitrile, 2, 2'-azobis (2,4-dimethyl-pentanenitrile, 2,2'-azobis (2-methyl-heptanonitrile, 2 - [(l-cyano-l-methylpropyl) azo] -2-methyl-heptane'nitrile, 2- [(l-cyano-l-methylbutyl) azo] -2-methyl-heptanonitrile, 2 - [(l-cyano-1,3-dimethylbutyl) azo] -2-methyl -heptanonitrile, 2- [(1-cyano-1-methyl-yl-yl) azo] -2,4-dimethyl-pentanenitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-methyl-pentanenitrile, 2- [(1-cyano-l-methylpropyl) azo] -2,4-dimethyl-pentanenitrile.

7. The composition according to claim 3, characterized in that it is selected from the group consisting of mixtures E, F and G: E. 2,2'-azobis (2-methyl-butanonitrile, 2,2'-azobis (2-methyl) -pentanonitrile, 2, 2'-azobis (2-methyl-heptanonitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-met il-heptanonitrile, 2- [(1-cyano-l-methylbutyl) azo] -2-methyl-heptanonitrile, 2- [(l-cyano-l-methylpropyl) azo] -2-methyl-pentanenitrile, F. 2,2'-azobis (2-methyl-butanonitrile, 2, 2 '- azobis (2-methyl-pentanenitrile, 2, 2 '-azobis (2-methyl-octanitrile, 2- [(1-cyano-l-methylpropyl) azo] -methyl-octanenitrile, 2- [(1-cyano-1) -methylbityl) azo] -2-methyl-octanitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-methyl-pentanenitrile, G. 2, 2'-azobis (2-methyl-butanonitrile, 2 , 2'-azobis (2-methyl-pentanenitrile, 2, 2'-azobis (2-ethyl-butanonitrile, 2, 2'-azobis (2-methyl-heptanonitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-methyl-heptanonitrile, 2- [(1-cyano-l-methylbutyl) azo] -2-methyl-hept anonitrile, 2- [(1-cyano-l-ethylpropyl) azo] -2-methyl-heptanonitrile, 2- [(1-c-ano-l-methylpropyl) azo] -2-methyl-pentanenitrile, 2- [( 1-cyano-l-ethylpropyl) azo] -2-methyl-pentanenitrile, 2- [(1-cyano-l-methylpropyl) azo] -2-ethyl-butanonityl.

8. A process for the preparation of azodinitrile mixtures characterized in that it comprises reacting an effective ratio of three or more different aminonitriles of the formula R2-C-NH2 CN wherein Ri and R2 are each independently selected from the group consisting of aliphatic hydrocarbon radicals, acyclics of 1-9 carbon atoms, with 5% to 15% by weight based on the reaction mixture of a metal hypochlorite , M (OCl) x, wherein M is selected from the group consisting of sodium, potassium or calcium, and x is the valence of M, in an aqueous medium in the presence of 0.25 a 10% by weight based on the weight of aminonitrile of an active surface compound or mixtures thereof having a hydrophilic-lipophilic moiety of 8 to 35 at a temperature of -10 ° C to 30 ° C, the metal hypochlorite and alpha-aminonitrile are present in an equivalent ratio of 1: 1 to 2: 1 from hypochlorite to aminonitrile and recovering from the reaction product a mixture of aliphatic azodinitrile compounds of the formula R2-C-N = N-C-R4 CN CN wherein Ri, R2, R3 and R are each independently selected from the group consisting of aliphatic hydrocarbon radicals, acyclics of 1-9 carbon atoms.