CS237123B1 - The preparation of 1,1‘-azobisformamide - Google Patents

Abstract

The invention provides a method for the production of 1,1'-azobisformamide by oxidizing hydrazodicarboxanide with hydrogen peroxide in the presence of a strong acid and bromine compounds. Oxidation is carried out in the presence of ammonium molybdate, molybdenum oxide or a complex of molybdenum or tungsten salts with triethanolamine, while the content of catalytic components of molybdenum or tungsten for hydrazodicarbonamide is 0.1 to 10 percent by mass. Oxidation takes place at a temperature of 25 to 65 °C in hydrochloric or sulfuric acid and in the presence of hydrobromic acid or its salts.

Description

237123

The present invention provides a process for the preparation of 1,1'-azobis-formamide (synonymous with azodicarbonamide, azodicarboxylic acid diamide, azodiocarboxamide, azoplastone, which is used as an additive to plastics. Most commonly, it is a functional application for use in plastics and rubbers. -Azobisformamide releases nitrogen when heated, and its decomposition products are not toxic.

The most common industrial production of azoplastone is 1,1-hydrazobieformamide (hydrazocarbonamide, hydrazocarboxamide). This process is oxidized by sodium dichromate or chlorine.

This processing of the azoplastone production overrides and creates additional problems in the non-complete sludge recycling, since these also contain Cr + 6 compounds and organic matter admixtures. As is generally known, the work of dichromans is very demanding, inakolkotieto; the compounds often cause the formation of eczema and allergy may occur upon contact with chromates and chromosomes. Occupational diseases are becoming increasingly prevalent in the relevant workplaces.

The oxidation of Ι, β-hydrazobisformamide chlorine is also a relatively demanding operation and complications arise if a chlorine source is not available in the respective production plant.

Preferred 1,1‘-hydrazo-bisformamide oxidants include 30 to 60 wt. hydrogen peroxide solution in water. The oxidation itself can be carried out in an aqueous suspension in the presence of bromine or yoga compounds, inorganic acids, optionally solicon elements. In the literature, the influence of salt metal is reported to reduce the decomposition temperature of the azoplaston (e.g., NSR Pat. No. 2,341,928). Hydrogen peroxide oxidation is carried out in the presence of inorganic salts of chromium, manganese, cobalt, nickel, tungsten, aluminum and tin. A hydrogen peroxide oxidation catalyst (30 percent by weight H 2 O 2) is used for the hydrogen peroxide oxidation; also in combination with bromine or iodine compounds (German Patent No. 2 548 592), also known as selenium dioxide (Japan Kokai 73 32 830).

According to the invention, the process for producing 1'-azobisformamide by hydrogenation of hydrazodicarboxamide with hydrogen peroxide in the presence of a strong acid and a bromine compound is such that the oxidation takes place in the presence of ammonium molybdate, oxidum-molybdenum or a salt of imolybdenum or tungsten salts with triethanolamine, wherein the content of the molybdenum or tungsten catalytic constituents to the hydrazodicarboxamide is 0.1 to 10% by weight. and the reaction was run at 25-65 ° C. 1,1'-Azobisformamide is prepared in high yield by oxidation of 1,1'-hydrazobisimidamide (hydrazodicarboxamide) in aqueous suspension with an aqueous solution of hydrogen peroxide and in the presence of bromine compounds in the environment of inorganic acid and catalyzed by molybdenum salts and its complexes as well as tungsten complexes with organic alkanolamines such as mono-, di-, tri-ethanolamine, isopropanolamines, general compounds obtained by addition and / or polyaddition of alkylene oxides to primary and / or secondary secondary amines. Mixtures of alkanolamines are also used for the preparation of the complex, and the complex can be formed directly in the reaction medium after the addition of the metal and the alkanol amine.

The concentration of the metal compound is between 0.1 and 10% by weight. to the oxidized hydrazo derivative, preferably 0.1 to 5% by weight of the reaction mixture, are added to the bromine compound soluble in the oxidation reaction system. Of these compounds, sodium, lithium, potassium, ammonium, and other water-soluble bromides may be used, respectively. quaternary ammonium salts of Br. These salts are applied in amounts of 0.1 to 5% by weight. to hydrazo-carboxamide.

The oxidizing agent, hydrogen peroxide, is used to terminate 30 to 60 wt. and in a molar ratio to hydrazocarboxamide of from 1.05 to 1.5: 1. The advantage of using this oxidation system is the fact that by-products do not produce undesirable by-products that need to be recovered or removed. One peroxide is used from the peroxide hydrogen to oxidize and water is formed to dilute the aqueous solution (in suspension) in which the oxidation takes place. After crystallization of the respective aqueous solution, it can be used several times for oxidation. In this process, the difficulty of expensive and time-consuming processing of chromium waste liquors is avoided.

The oxidation of the hydrazocarboxamide is carried out in the presence of acids such as hydrochloric acid, hydrobromic acid, nitric acid, sulfuric acid, phosphoric acid, organic formic acid, acetic acid, propionic acid, n-butyric acid, isobutyric acid. The concentration of said acids ranges from 5 to 15% by weight (MCI, HBr, HsPO4, HNO3), 10 to 40% by weight (H2SO4) and 5 to 20% by weight in organic acids. In the case of the use of hydrobromic acid, the use of bromo-oxidizing compounds is not necessary. For oxidation, a hydrazodicarboxamide concentration of 15 to 30% by weight is suitable in the system. The reaction temperature is 25 to 65 ° C. The oxidation reaction time is temperature dependent and is 0.3 to 4 hours. Example 1

250 ml of 8% HCl, 2.5 2 71 71 3 with 6 grams of 97% HBr, 1 g are placed in an oxidation apparatus consisting of a three-neck flask equipped with a stirrer, a thermometer, a low temperature cooler and a separating funnel. MoO 3 and 118 g (1 mol) of hydrazodicarbonamide were added. Thereafter, 125 g (1.1 mol) of a 30% strength hydrogen peroxide solution was metered in at room temperature with a separating liquid. The reaction mixture is heated to 50 ° C and stirred for 1 h. The heater is then heated to 80 ° C for 0.5 h. It is filtered off with suction and washed with 2 x 200 ml of cold water. Drying yields 110 g of 1,1'-azobisformamide, representing a 94.8% yield of the base. The purity is greater than 99.8% by weight, the decomposition temperature is 195 to 205 ° C, the amount of gas released is 220 ml / g. Example 2

Into the oxidation apparatus according to Example 1, the basic raw materials according to Example 1 were used as a metal catalyst using 1 g ammonium molybdate [(NH 3 / M 2 O 4 · 4H 2 O]). -azobis-formamide (94% yield), m.p. 190 DEG-205 DEG C., 215 ml / g. The purity of the product was 99.8%.

The waste water from the oxidation of Example 1 is removed off before the washing is started and concentrated by distillation of 110 g of water.

The concentrated wastewater is charged to the oxidation apparatus of Example 1. 118 g (1 mol) of hydrazodicarbonamide are added and 125 g (1.1 mol) of 30% H 2 O 2 are added from the separating funnel. The reaction mixture is heated to 50 ° C and stirred for 1 h, further heated to 80 ° C and stirred for 0.5 h. The suspension® is filtered off, the effluents are discarded for further use and the crude product is washed with 2 X 200 miles of water . 109 g (94.0% yield theory) are obtained. The purity of the product is greater than 99.8% by weight, the decomposition temperature is 190 to 205 degrees C, the amount of gas released is 215 ml / g. Example 4

600 ml of 2% HBr and 1 ammonium gmolybdate and (NH4) eMo7O24.4H2O are charged into the oxidation apparatus described in Example 1.

118 g (1 mol) of hydrazodicarbonamide are suspended in this solution and 125 g (1.1 mol) of 30% H2O2 are metered in from the separating funnel. The mixture was then stirred for 1 h at 30 ° C and for a further 1 h at 50 ° C. The product is filtered off and the wastewater is discarded for further use.

After drying, 113 g of 1,1‘-azobisformamide are obtained (97.4% of theory). The purity of the product is at least 99.9% by weight, the thermal decomposition temperature is 195 to 205 CC, the amount of gas released is 220 ml / g.

Into the oxidation apparatus, the raw materials according to Example 4, except for molybdenum ammonium, are replaced by 1 g of MoCl 2, admixed with the working procedure of Example 4. 115 g of l'-azobisphosphamide (with a purity of at least 99.8% by weight) are obtained. The amount of gas released is 220 ml / g. Example 6

The waste water from the oxidation of Example 5 is concentrated by evaporation of about 110 grams of water. The concentrated solution of sanasadium into the oxidation apparatus and mixed with 118 g (1 mol) of hydrazodicarbonamide. Then 125 g (1.1 mol) of 30% H 2 O 2 are added slowly and the reaction mixture is stirred for 1 h at 30 ° C, then at 1 ° C. h is heated to 50 ° C. After filtration and washing of the product, 112 g (96.6% by weight of the theoretical) of 1,1-isobisformamide with a purity of 99.8% are obtained. The decomposition temperature is 195 to 205 degrees C, the amount of gas released is 220 ml / g. Example 7

280 ml water, 17.7 g conc. H2SO4, 14.3 g 47% HBr and 1 g MoOs. 118 g (1 mol) of hydrazodicirone monimide are suspended in this solution and then 125 g of 30% H 2 O 2 are metered in at 30 ° C for 1 h. The reaction mixture is then stirred for an additional 1 h. dries. The filtered solution is concentrated by evaporation of 110 g of water and further oxidation is used. 108 g (93.1% of theory) of Ι, β-azobisformamide with a decomposition temperature of 200 to 205 ° C are obtained, the amount of gas released is 225 ml / g. Purity is at least 99.8 percent by weight. Example 8

While maintaining the procedure, all the components as in Example 7 are added to the oxidizer, except for water, which is replaced with 280 millimeters of aqueous ethanol (1: 1 weight ratio) and hydrobromic acid sanahr 8.5 g NaBr. 112 g (96.6% of theory) of 1,1-azobisformamide with a decomposition temperature of 195 to 200 ° C are obtained, the amount of gas released is 225 ml / g. The purity is at least 99.8% by weight

The oxidation is carried out according to Example 7, with

Claims (2)

1 g of MoO 3 is replaced with 1 g of ammonium molybdate [composition (NH 4 O 2 O 4 H 2 O]) to give 111 g (95.7% of theory) of 1,1'-azobisformamide with a decomposition temperature of 200 to 205 Example 10 To the apparatus described in Example 1, 230 ml of water, 186.2 g of urea (3.1 mol) and 134 g of hydrazine sulphate (1.02 mol) were added. with stirring, heat the reflux temperature for 6 h. Then cool to 30 ° C, add 18 g of ko, NH 2 SO 4.8.5 g of NaBr and 1 g of MoO 2. The mixture is stirred for a further 1 h. The product is filtered off with suction, washed with hot water for 3 x 200 ml, 2 x 200 ml of cold water and dried. 110 g (93.2% of theory) are obtained. Ι, Γ-azo-bisformamide and a decomposition temperature of 195 to 205 degrees C, an amount of gas released of 220 milliliters / g. The purity of the product is at least 99.8% by weight. 250 ml of 8% HCl, 2.5 g of 47% HBr, 1 g of uranyl acetate [U2O2CH2COO2O2H2O] are added. 118 g (1 mol) of hydrazodicarbonaroide are suspended in this mixture. During 1 h at 30 ° C, 125 g (1.1 mol) of 30% H 2 O 2 are added. The reaction mixture is stirred for an additional 1 h at 50 ° C. After the product was filtered off, the waste water was concentrated by evaporation of 110 g of water and used for further oxidation. The crude product is washed with 2 X 200 ml of cold water and, after drying, 112.5 g (97% of theory) of .beta.-azobisformamide with a decomposition temperature of 200 DEG to 205 DEG C. are obtained, the amount of gas released is 220 ml / g. EXAMPLE 12 250 ml of 8% HCl, 2.5 g of 47% HBr, 1.05 g of a tungsten complex formed in the reaction mixture of 0.5 g of WO3 are charged to the oxidation apparatus. Thereafter, 118 g (1 mol) of hydrazodicarbonamide are stirred in the reaction mixture and 125 g (1.1 mol) of 30% IT2O2 are added at 30 DEG C. The reaction mixture is then stirred. 1 h at 50 [deg.] C. The product is filtered, washed with 2 * 200 ml of water and concentrated to give 113 g (97.4% of theory) of 1,1 ' -azobisformamide with a decomposition temperature of 195-205 [deg.] C., The purity of the product is greater than 99.8% by weight. Example 13 The oxidation is carried out according to Example 12, the lenoxidation catalyst is prepared separately. 0.5 g of WO3 + 0.55 gtriethanolamine 0.5 g of water is mixed into the tube and heated to 100 DEG C. for 3 h. The resulting dark oily liquid is added to the oxidation mixture and the Example 12 is used. 112.5 g (97% of theory) of 1,1'-azobisformamide with a decomposition temperature of 195 to 205 ° C are obtained, the amount of gas released is 120 ml / g. Product purity is at least 98.8% by weight. EXAMPLE 14 An example of Example 12 was charged to the oxidation apparatus of Example 12. 10 g of an aqueous solution of heteropolyphosphoric molybdenum acid and vanadium were used as the oxidation catalyst (8.3 wt% Mo and 5.03 wt% aqueous solution). % by weight bound to polyphosphoric acid). The work-up of Example 12 yields 113 g (97.4% w / w) of Ι, β-azobisformamide with a melting point of 195 to 200 ° C, the release rate is 220 ml / g and 99% purity. . OBJECT CLAIMS 1. A process for producing Ι, β-azobisformamide by oxidizing a hydrogen peroxide hydrazodicarboxamide in the presence of a strong acid and a bromine compound, characterized in that the oxidation is carried out in the presence of 0.1 to 10 percent by weight. the ammonium molybdate catalyst, the lybdene oxide or the molybdenum or tungsten salt complex with triethanolamine, calculated as starting hydrazodicarbonamide. 2. A process for producing Ι-azobisformamide according to claim 1, wherein the oxidation takes place at a temperature of 25 to 65 ° C. Severogi-alia, n. P., Race 7, Ceoa Bridge 2.40 Kcs