CS232248B1 - A method for producing an antioxidant based on hexamethylentetramine and substituted phenols - Google Patents

Abstract

The invention relates to a method for producing antioxidants based on hexamethylenetetramine and substituted phenols in a mineral oil environment at temperatures higher than 120 °C.

Description

(54) Method for producing an antioxidant based on hexamethylenetetramine and substituted phenols

The invention relates to a method for producing antioxidants based on hexamethylenetetramine and substituted phenols in a mineral oil environment at temperatures higher than 120 °C.

- 1232 248

The invention relates to a method for producing antioxidants based on hexamethylenetetramine and substituted phenols.

In rubbers containing unsaturated polymers, the presence of antioxidants is required. Phenyl-$~naphthylamine (PBN) is most often used for this purpose. Since technical PBN contains carcinogenic additives, there is an effort to replace it with chemicals that are less harmful to health. Therefore, rubber stabilization is used using substituted phenolamine antioxidants (V.V. Mojsejev et al., patent ČSSE 185 871). The advantage of these antioxidants, suitable mainly for butadiene-styrene oil-modified rubbers, is the fact that they are highly effective at low concentrations compared to commonly used antioxidants. Their preparation is carried out by heating a mixture of substituted phenols and hexamethylenetetramine (HMT) to temperatures higher than 120 °C, while part of the phenol can be replaced with hydroxybenzoic acids (V.V. Mojsejev et al., patent ČSSE 184 981).

The disadvantage of this method of preparing antioxidants is that the reacted mixture is discharged from the reactors and, after cooling, is crushed and ground into a fine powder, which can be dissolved in extender oils and added in this form to the latex during coagulation. Another disadvantage of this method is the high viscosity of the reaction mixture in the last stage of polycondensation and the associated high energy demand of the antioxidant preparation process.

The above-mentioned disadvantages are eliminated by the invention, which consists in the fact that antioxidants based on hexamethylenetetramine and substituted phenols are prepared at temperatures above 120 °C, by carrying out the polycondensation reaction.

232 248

-characteristics: 6 ·» 50 mm ² /s 0.8 «ť 1 5 «£ 40 56 180 eí 260 °C in the presence of 20«é2000 mass«edMi<J| parts by weight of mineral oil with an aromatic carbon content of 5<£40#, preferably 100 and2 230 mass»w$t»wlf parts by weight of mineral oil with an aromatic carbon content of 30t£38$, per 100 massWessirtieíi parts of reaction components, wherein the mineral oil is added either at once before the start of the polycondensation^ or is added during the course of the polycondensation reaction.

The term mineral oil refers to medium and heavy fractions from the distillation of crude oil with the following kinematic viscosity at 100 °C V Η K (viscosity-density constant) aromatic carbon content flash point

The term highly aromatic oil refers to heavy fractions of mineral oils used for the adjustment of butadiene-styrene rubbers. Their aromatic carbon content is around 36%. These oils are very good solvents for phenol-based resins with aralkyl substituents. Refined oils can also be used as solvents, in which the aromatic carbon content is usually about two times lower, and are therefore particularly suitable for phenol-based resins with long aliphatic substituents. In addition, they are characterized by low viscosity.

The method according to the invention enables easier heat transfer at high degrees of polycondensation and easier escape of ammonia from the reaction mixture. The main advantage, however, is that several subsequent production operations can be omitted during production, i.e. discharging the solidifying product, its crushing, grinding and dissolving. The low viscosity of the resulting product also enables perfect emptying of the reactor. This production process does not require the use of reactors of special designs.

-5Example 1 232 248

A mixture consisting of 258.6 g of nonylphenol and 45.7 g of hexamethylenetetramine (HMT) was placed in a 1.5 liter stainless steel reactor equipped with a stirrer (120 rpm), which was heated for 200 minutes at a temperature of 140 °C. After cooling, a brittle resin was obtained, which was crushed into a fine powder suitable for dissolution in mineral oils.

Example 2

To 304.3 g of a mixture (100 hmefr.d·) of the same composition as given in Example 1 (258.6 g nonylphenol, 45.7 g HMT), 565.1 g (185.7 hmefc.d.) of refined mineral oil with the trade name R-933* was added. The oil used had the following characteristics:

kinematic viscosity at 100 °C 7.2 mm ² /s specific gravity at 20 °C 910 kg/m^

V Η K 0.857 flash point 201 °C carbon content corresponding to aromatic hydrocarbons 18 % paraffinic hydrocarbons 55 % naphthenic hydrocarbons 23 %

The mixture was heated to 180 °C and maintained at this temperature for 1 hour. After the reaction, a very well-flowing solution of the antioxidant in mineral oil was obtained. The solution was suitable for dosing into butadiene-styrene latexes during coagulation. Due to its relatively low viscosity at low temperatures, the solution is also fully suitable for transportation.

Example 3

To 304.3 g of a mixture (100 wt.d·) of the same composition as given in Example 1 (258.6 g of nonylphenol and 45.7 g of HMT), 565.1 g (185.7 wt.d·) of highly aromatic

232 248

oils with the trade name Triumf with the following characteristics tick: Kinematic viscosity at 100 °C 20 mm^/s specific gravity at 20 °C 990 kg/ ^m3 In the 0.948 flash point 240°C carbon content corresponding to aromatic hydrocarbons 36 * paraffinic hydrocarbons 26 # naphthenic hydrocarbons 38% The mixture was heated to a temperature of 180 °C and at this temperature maintain-

stirred for 1 hour. Once the ammonia evolution had ceased, the reaction mixture was cooled to 80 °C and prepared for dosing into the butadiene-styrene latex during coagulation*

Since the viscosity of the antioxidant oil solution prepared in this way is quite high at laboratory temperature, the solution is not very suitable for transportation.

This example illustrates the possibility of preparing antioxidant solutions directly at the butadiene-styrene rubber manufacturer.

Example 4,,

To 100 cups of a mixture with a high molar ratio of reactants, i.e. 332.2 g of nonylphenol (1.47 mol) and 45.7 g of HMT (0.326 mol), 184.5 g (50 wt<t.d.) of refined oil R-933 was added and the mixture was heated at 160 °C for 30 minutes. An oil solution of the antioxidant with a very viscous consistency was formed.

Example 5

A mixture of 282 g (81.7 h4d.) nonylphenol, 54 g (15.7 h4d.) HMT, 9 g (2.6 hmid.) salicylic acid, 1035 g (300 hrad.) Purex 433 high aromatic oil was heated at 140 °C for 30 minutes. The used

- 5 232 248 oil me}, the following characteristics:

kinematic viscosity at 100 °C 13.4 mm ² /s specific gravity at 20 °C 1018 kg/m^

V Η K 0.990 flash point 212 °C carbon content corresponding to aromatic hydrocarbons 40 % paraffinic hydrocarbons 12 % naphthenic hydrocarbons 48 %

Then the temperature of the reaction mixture was increased to 180°C for another 30 minutes. After completion of the polycondensation, an oil solution of antioxidant with a concentration of 25% was obtained, which was suitable for stabilizing butadiene-styrene rubbers in the latex stage.

Example 6,

A mixture of 242.1 g of octylphenol (84.1 wt. d.), 45>7 g (15.9 wt. d.) of HMT and 863.4 g (300 wt. d.) of Triumf highly aromatic oil was gradually heated to a temperature of 180 °C and left at this temperature for 1 hour. After the evolution of ammonia was complete, an antioxidant solution was obtained, which was suitable for stabilizing butadiene-styrene rubbers in the latex stage.

Example 7.

A mixture of 232.7 g (83.6 wt.) of styrenated phenol (Antioxidant 3, product CHZJD Bratislava) and 835.2 g (300 wt.) of highly aromatic oil Triuliý was heated at 150 °C for 30 minutes and another 30 minutes at 180 °C. After cooling to 60 °C, the resulting oil solution was suitable for dosing into butadiene-styrene latexes.

- 6 Example 8

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A mixture of 300 g (&3.3 hmid*) cumylphenol (isolated from wastes arising from the production of phenols via cumene hydroperoxide), 60 g (16.7 hmi.d.) HMT and 1080 g (300 hmi.d.) Purex 433 highly aromatic oil was heated for 35 minutes at 180 °C. After cooling to room temperature, a 25 fr-vd resin solution was obtained, which at temperatures above 40 °C was suitable for dosing into butadiene-styrene latexes*

Claims (1)

SUBJECT OF THE INVENTION 232 248 A process for the production of hexamethylene-based antioxidants of tramin and substituted phenols by polycondensation at temperatures above 120 ° C, characterized in that the polycondensation reaction is carried out in the presence of 20 to 2000 parts by weight of a mineral oil having an aromatic-bonded carbon of 5 to 40 $. 100 to 250 parts by weight of a highly aromatic oil with an aromatic-bonded carbon content of 50 to 58%, per 100 parts by weight of the reaction components, wherein the mineral oil is added either at the same time before the polycondensation starts or during the polycondensation reaction