CS232350B1 - Processing of 2,2-azobisizobutyrnitrile - Google Patents

Abstract

The invention provides a process for the preparation of 2,2-azobisobutyronitrile from hydrazine and / or its addition compounds via 2,2-hydrazobisisobutyronitrile as an intermediate to which is added with hydrogen peroxide in an aqueous medium the mineral acid is added and / or and in the presence of compounds brroda so that the hydrogen peroxide is added the 2,2-hydroxy-isobutyronitrile is catalysed at least one element and / or at least one compound of molybdenum, vanadium, tungsten 9 uranium at 0 to 50 ° C with a molar ratio of 2,2-hydrazobisisobutyronitrile to the catalytic component is 1: 0.00.0 1 to 0.1 and 2,2-azobisobutyronitrile formed is isolated.

Description

MACHO VENDELÍN prof. ing. DrSe., NEWS, BALÁK JIŘÍ ing. CSc., SOUP MILAN ing. CSc., PRIEVIDZA, LETZ ŠTEFAN ing., ŽILINA (54) Production method of 2,2'-azobisisobutyronite

SUMMARY OF THE INVENTION The present invention provides a process for the preparation of 2,2-azobisisobutyronitrile from hydrazine and / or its addition compounds via 2,2-hydrazobisisobutyronitrile as an intermediate to which it is treated with hydrogen peroxide in an aqueous medium with a mineral acid and / or organic acid. The presence of bromine compounds such that the addition of hydrogen peroxide to 2,2-hydroxybisisobutyronitrile by catalysis is at least one element and / or at least one compound of the elements molybdenum, vanadium, tungsten 9 uranium at a temperature of 0 to 50 ° C, the molar ratio 2 The 2-hydrazobisisobutyronitrile to the catalyst component is 1: 0.00.0 1 to 0.1 and the 2,2-azoblsisobutyronitrile formed is isolated.

23235C

- 2 232350

The present invention relates to a process for the preparation of 2,2-azobisisobutyronitrile (AZDN) which is a suitable initiator of polymerization reactions.

The present invention provides a process for producing AZDN via 2,2-hydrazobisisobutyronitrile (HAZDN) by oxidizing it in an aqueous suspension in the presence of a strong acid and a bromine-containing compound with hydrogen peroxide in the presence of molybdenum, tungsten, vanadium, cobalt, uranium alone or mixtures thereof.

The production of AZDN by oxidation of HAZDN with chlorine gas is described, but has some disadvantages. The oxidation of Cr salts with chromium is also environmentally demanding, mainly because of their toxic / toxic properties. skin eczema.

The known oxidant is hydrogen peroxide. Oxidation of HAZDN is carried out in its aqueous suspension and in the presence of bromine, iodine, strong acid and catalytic impregnation of selenium or tellurium / Otsuka Chem.

What. Ltd.: Jap. Kokai 77,144,622].

According to the present invention, there is provided a process for producing 2,2-azobisisobutyronitrile from hydrazine and / or its addition compounds via 2,2-hydrazobisisobutyronitrile as an intermediate to which it is treated with hydrogen peroxide in an aqueous medium in the presence of a mineral acid and / or organic acid and compounds. of bromine is carried out by catalyzing the hydrogen peroxide to 2,2-hydrazobisisobutyronitrile with at least one element and / or at least one compound of the elements molybdenum, vanadium, tungsten, uranium at a temperature of 0 to 50 ° C, preferably 20 to 35 ° C wherein the molar ratio of 2,2-hydrazobisisobutyronitrile to catalyst component is 1: 0.0001 to 0.1 and the 2,2-azobisisobutyronitrile formed is isolated.

The oxidation system consists of suspended 2,2-hydrazobisisobutyronitrile in water and contains bromine, hydrobromic acid, bromine compounds such as NaBr, KBr, LiBr, NH 4 Br or other water-soluble bromine compounds, respectively. quaternary ammonium bromides in an amount of 0.1 to 10% by weight, preferably 0.1 to 5% by weight; to the hydrazo derivative. Catalyst components in an oxidized system are compounds of some elements which have the ability to accelerate the transfer of oxygen from the peroxide and mediate the smooth conversion of the hydrazo derivative to the azo derivative. In the absence of metal catalysts, the reaction proceeds slowly, resulting in lower product yields, increased energy consumption and oxidation time. The molar ratio of the oxidized 2,2-hydrazobisisobutyronitrile intermediate to the catalyst component is 1: 0.0001 to 0.1. In the case of a metal catalyst which carries oxygen, the molar ratio mentioned should be understood as atomic. The catalytically active ingredients can be applied as oxides, salts (ammonium, alkaline) and complexes where amino reagent ligands are used. Their solubility / reaction medium is preferred. The respective complex can be prepared and applied as a pure substance separately, especially if it is produced, or the complex prepared in situ in the reaction medium by adding aminoligands to the reaction medium to the corresponding salt of the catalyst used (Mo, W, V and mixtures thereof). Molybdenum and vanadium heteropolyphosphates are also effective. Of the aminoligands used, aminoalcohols, aliphatic amines, pyridine bases as well as aromatic amines are preferred. The actual oxygen donor in the oxidation is hydrogen peroxide, which can be used at a concentration of 20 to 60% by weight. and in order to achieve optimum product yields, it is advantageous to dispense it with 1.05 to 1.5 molar excesses relative to 2,2-hydrazobisisobutyronitrile. environmentally friendly. Due to the stability of the product formed, the oxidation can be carried out at a temperature of 0 to 50 ° C, but in view of the practical application of the manufacturing process, it is preferable to operate at a temperature of 20 to 35 ° C.

The starting material for the synthesis of acetone cyanohydrin is prepared by a known method from acetone and hydrogen cyanide. The subject of the present invention is the catalytic oxidation of 2,2'-hydrazobio-i-

Claims (4)

sobutyronitrile, which is also prepared by a known process from hydrazine and acetone cyanohydrin. Example 1 to 8 Oxidation apparatus aa consists of a flask of 2,5 dm ³ , equipped with a stirrer, a thermometer, a separating funnel and a reflux condenser. 400 cm @ ^{3 of} hydrochloric acid having a concentration of 8% by weight, 2.5 g of hydrobromic acid having a concentration of 47% by weight, are poured into the apparatus. and a metal catalyst (see Table 1). 166.2 g (1 mol) of 2,2'-hydrazobisisobutyronitrile (HAZDN), which is in the form of suapenzy, are metered into this solution. 125 g (1.1 mol) of hydrogen peroxide at a concentration of 30 wt. at 29-1 ° C. This temperature is maintained for 5.5 hours, then at 30 ° C for 30 minutes. The product is worked up by filtration, washing three times with 200 cm ^{3 of} water at a temperature of 15 ° C to 30 ° C under reduced pressure drying at 35-2 ° C. 2,2'-Azobisisobutyronitrile (AZDN) is obtained, in extracts and in purity, as shown in Tab. First Example 9 The evaporated water obtained as described in Example 1 was evaporated (100 cm ³ ). Then 166.2 (1 mol) HAZDM and hydrogen peroxide 125 g (1.1 mol) are added. After the hydrogen peroxide was metered in, the temperature was maintained at 30 ° C for 5 h and for a further 1 h at 50 ° C. 156 g (95% yield) of AZDN were isolated after work up. After evaporation of the wastes three times, 1 g of 47 wt% hydrobromic acid and 0.5 g of oxidation catalyst should be added. 3 to 5 oxidations can be carried out with this batch. Examples 10 to 13 400 cm @ ³ of hydrobromic acid at a concentration of 2% by weight are metered into the oxidation apparatus specified in Example 1. and catalyst (Table 1). 166.2 g (1 mol) of HAZDN and hydrogen peroxide, 125 g (1.1 mol) are then added at a temperature of up to 30 ° C. The oxidation is carried out for 5.5 hours at 30 ° C and 0.5 hours at 50 ° C. After working up (see Examples 1 to 8), AZDN is obtained in yield and purity as specified in Tab. First Example 14 It describes recycled after evaporation of 100 cm ^{3 of} waste water from the experiment described in Example 10. 166.2 g (1 mol) of HAZDN and 30% by weight hydrogen peroxide are added. in an amount of 125 g (1.1 mol). The temperature is maintained at 30 ° C for 5.5 h and 0.5 h at 50 ° C. The reaction mixture is further worked up as outlined in Examples 1-8. The yield of the product is 95.3%, the purity is 99.5%. Examples 15 to 21 Weigh 500 g of water, 25 g of conc. sulfuric acid, 12 g of sodium bromide and catalyst (specification in Table 2). 166.2 g (1 mol) of HAZDN and 30% by weight hydrogen peroxide are added with stirring. (125 g, 1.1 mol). The reaction mixture was further stirred for 3 h at 20-30 ° C (as shown in Table 2) and 0.5 h at 50 ° C. Treatment of the product yields the final AZDN product in yield and purity as specified in Table 2. Second Example 22 It describes recycling after evaporation of 100 cm ^{3 of} waste water and the experiment described in Example 15. Oxidation of HAZDN is carried out with hydrogen peroxide (125 g) for 3 hours at 30 ° C and 0.5 h at 50 ° C. After four oxidations according to this procedure, the addition is carried out 0.25 g of vanadium pentoxide (or other catalysts), 3 g of sodium bromide and 5 g of concentrated sulfuric acid treat the waste water. These waters are used for further oxidation. Working up of the product gave AZDN in 96.2% yield and 99% yield. Example 23 - Reference Example The oxidation is carried out according to the procedure of Example 15 to 21 except that a metal oxidation catalyst is not used. Work-up of the product gave the desired product in 16.8% yield. Example Oxidative Ayatene Catalyst Teplete Product 8% HCl H ₂ SO. ⁺ kind ° C Yield Purity bt tn tn tn tn tn tn tn tn tn tn tn tn tn tn tn tn ιη tn tn tn <n <* V m <n <n m <*> m n <n what he ΓΠ m m m m M · 0 0 0 0 0 0 0 0 0 0 0 0 0 about 0 0 0 0 ABOUT 0 0 * " ** * " * " ** · " *** T * " tn tn tn tn tn tn tn tn tn 1 tn CM CM CM m CM CM <M CM CM CM CM CM CM CM CM CM <n CM m ro m ABOUT ABOUT ABOUT 0 ABOUT ABOUT ABOUT ABOUT 0 ABOUT 0 ABOUT 0 0 0 0 0 0 0 0 0 tn tn Ό within tn tn tn tn tn tn tn 00 tn <& ch σν <h σν ch σ> <h ch σν σν ch σν ch σν σν σν σν ch ch σν σν VO σν σν ch σν σν σν <h ch ch σ \ ch <h σν σν s σν σν <h σν σν σν · - 01 (0 01 o - ir \ m