RU2656332C1 - Process for preparation of quinone diimine antioxidant for solution rubbers - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to process for preparation of a quinone diimine antioxidant for solution rubbers. According to the method of invention, an alkylate, obtained in the process of alkylation of 4-aminodiphenylamine with 2-ethylhexanol in the presence of potassium hydroxide at a temperature of 190–235 °C with stripping of an azeotrope of alcohol with reaction water, containing N-2-ethylhexyl-N'-phenyl-p-phenylenediamine, a 10–19 % sodium hypochlorite solution in amount of from 0.10 to 0.20 mole per 1 mole of N-2-ethylhexyl-N'phenyl-p-phenylenediamine contained in the alkylate. Wherein temperature of about 25 °C is maintained. After completion of dosing of sodium hypochlorite, the resulting reaction mass is washed by addition of water, mixed, sedimented, the aqueous layer is separated from the organic layer, operation of washing and separating the aqueous layer from the organic layer is repeated twice, after which the desired product is isolated from the organic layer. Desired product is a liquid mixture of N-2-ethylhexyl-N'-phenyl-p-quinone diimine and starting N-2-ethylhexyl-N'-phenyl-p-phenylenediamine with a mole ratio of these compounds from 10:90 to 20:80. Invention also relates to process for preparation of a quinone diimine antioxidant in which a hydrogen peroxide solution is used instead of a sodium hypochlorite solution, as well as to the quinone diimine antioxidant for the solution rubbers obtained by said methods.

EFFECT: proposed methods allow to obtain a quinone diimine antioxidant that can be used to fill polymer solutions of solution rubbers and excludes leaching and evaporation of the antioxidant upon their isolation.

3 cl, 6 ex

Description

The invention relates to amine antioxidants, the technology for their preparation and can be used in the production of synthetic rubbers based on polydienes and copolymers of dienes with olefins.

It is known to use as the most effective antioxidants (AO) in the production of synthetic rubbers, mainly solution polymerization (isoprene, butadiene and styrene butadiene) of secondary aromatic amines and diamines, as well as mixtures thereof.

The most effective among them are derivatives of N-alkyl-N'-phenyl-p-phenylenediamines (PFDA derivatives) of the general structure:

where R is an alkyl radical of various structures.

However, in practice, the range of these compounds for use in the production of solution rubbers based on dienes and copolymers of dienes with olefins is limited by production conditions requiring:

- the complete solubility of AO in aliphatic solvents used in the manufacture of solution rubbers based on dienes and copolymers of dienes with olefins;

- the lack of evaporation and leachability of antioxidants at the stage of water degassing of crumbs of rubbers from solvents at the boiling point of water in degassers.

- prevention of mechanical entrainment and loss of AO together with water vapor in the communications of the return solvent, including the danger of the AO entering the return solvent, which leads to poisoning of the polymerization catalyst and clogging of the communications of the return solvent with deposits of AO;

- the absence of AO extraction with water from the rubbers of rubbers in worm squeezing presses and their entrainment with squeezing water into drains;

- the absence of AO losses from rubbers due to evaporation at the final stage of drying at high temperatures in expanders.

These requirements are satisfied by a relatively narrow circle of amine antioxidants, not completely devoid of the listed disadvantages.

So, among AOs for rubbers, 4-nitrosodiphenylamine (4-NDFA) is known ([1] Garmonov IV Synthetic rubber. - L .: Chemistry, 1983, US 4115636 A, publ. 09/19/1978), used for stabilization of synthetic cis-1,4-polyisoprene (PI) brand SKI-3-01. In the process of refueling and isolating this rubber, 4-NDFA is attached to the cis-1,4-polyisoprene macromolecules, as a result of which the obtained high molecular weight, fixed on macromolecules AO is not able to evaporate or wash out of rubber and rubbers obtained with its use, giving a number of rubber compounds other positive properties.

The disadvantage of 4-NDFA fixed on macromolecules is the partial leachability of its excess at the stage of degradation of rubber crumb, while the excess is taken in technology to provide the highest possible degree of grafting, taking into account the partial leachability of salts formed with 4-NDFA alkaline solutions of crumb anti-agglomerator, calcium stearate . As a result, part of the introduced 4-NDFA is discharged into wastewater, which with this admixture is not biodegradable and / or bio-treated.

For solution rubbers based on dienes and their copolymers with olefins, liquid mixtures of N-1,3-dimethylbutyl- and 1,4-dimethylpentyl-p-phenylenediamines are used as AO (at ratios from 45:55 to 55: 45%, mass .) under the trade names Santoflex 134, Flexzone 11L. a mixture of N-1,3-dimethylbutyl-p-phenylenediamine with N- (1,3-dimethylbutyl) -N'-4-cumylphenyl) p-phenylenediamine in a ratio of 45:55 under the trade name Dusantox L et al. ([2 ] Nasyrov I.Sh., Rakhmangulova E.E., Petrunina A.V., Bazhenov Yu.P., Kavun S. M. Comparative evaluation of the effectiveness of cis-1,4-polyisoprene antioxidants. Rubber and Rubber, 2009, No. 1 p. 11-14).

All of the above AO, derivatives of p-phenylenediamine (PFDA), are obtained from 4-nitrosodiphenylamine, previously reduced to 4-aminodiphenylamine (4-ADPA), followed by reductive alkylation with ketones such as acetone, 1,3-dimethylisobutylketone, 1,3- dimethyl isopentyl ketone. This method is carried out in high pressure reactors from 40 to 60 bar in a hydrogen medium, using expensive catalysts based on noble metals (platinum, palladium on coal, etc.) at temperatures above 100 ° C (Gorbunov B.N. Chemistry and technology of stabilizers of polymeric materials. - M.: Chemistry, 1981 [3]).

The methods listed above and the AO obtained with their help do not allow, however, to obtain an AO that gives the rubbers refueling them based on polydienes and copolymers of dienes with olefins a number of useful properties that approximate the properties of rubber compounds and rubber obtained from them to the properties of mixtures and rubbers from natural rubber (NK).

In addition, the use of well-known AOs for refilling solution rubbers is associated with losses of these AOs due to leaching of crumbs at the stage of water-steam degassing due to insufficiently high molecular weights (MM), entrainment with a return solvent, which leads to pollution of its communications and evaporation to drying stages in expanders, where temperatures reach 200-220 ° С on the “head”

There is also known a method for producing quinondiimine AO for rubbers, N-alkyl-N'-phenyl-p-quinondiimines, general structure

, где R-алкильный радикал различного строения и заключающийся в реакции окисления исходных АО для каучуков и резин на основе производных N-алкил-N'-фенил-п-фенилендиамина, в условиях селективного их превращения в целевые продукты реакцией растворов или расплавов исходных АО с подаваемыми дозируемыми порциями водными растворами окислителя - гипохлорита натрия либо других щелочных или щелочноземельных металлов, взятых в эквимолярном соотношении с исходным АО., Реакция осуществляется с использованием растворителей, их смесей, включая воду, независимо от растворимости АО в воде, либо без растворителя.

where the R-alkyl radical of various structures and consisting in the oxidation reaction of the starting AO for rubbers and rubbers based on derivatives of N-alkyl-N'-phenyl-p-phenylenediamine, under conditions of their selective conversion into target products by reaction of solutions or melts of the starting AO with aqueous dosing portions of aqueous solutions of an oxidizing agent - sodium hypochlorite or other alkaline or alkaline earth metals taken in equimolar ratio with the starting AO., The reaction is carried out using solvents, mixtures thereof, including water, regardless of the solubility of AO in water, or without solvent.

Alternatively, the treatment of the starting AOs to obtain the target quinondiimine AO (CDAO) is carried out with aqueous alkali solutions into which chlorine gas is blown to produce alkali metal hypochlorites and then the reaction mixture is mixed with the added solvent, then the organic phase is separated with the solution of the target product and the aqueous layer with metal chloride solutions and isolate the target product after distillation of the solvent.

The quinondiimine-type antioxidant (XDAO) obtained from p-phenylenediamine AOs, for example, N-1,3-Dimethylbutyl-N-phenyl-p-quinondiimine, introduced into rubbers based on polydienes or copolymers of dienes with olefins at the stage of manufacturing rubber compounds containing carbon black, at temperatures not lower than 140 ° C, it is able to join rubber macromolecules with the formation of AO fixed on polymer chains. This ensures the growth of quality indicators of rubber compounds, such as reduced viscosity, better dispersibility of fillers, for example, carbon black, silicic acid fillers, increased stress relaxation rate, which leads to a decrease in shrinkage of semi-finished products after profiling, increased resistance to premature vulcanization and increased quality indicators obtained from of these rubber mixtures - increased thermo-oxidative stability, especially after solvent extraction of rubbers, reduced losses to results ([4], US 6,184,276, publ. 02/06/2001).

The disadvantage of this method of producing quinondiimine AO (XDAO) is the need to use solvents, preferably polar or mixtures of non-polar solvents with polar solvents, to accelerate the process, and the need for their subsequent regeneration.

There is also known a method of producing CDAO for rubbers by oxidizing the corresponding starting materials for the synthesis of p-phenylenediamine AO (PFDA) with hydrogen peroxide (PV), comprising a metered supply of PV with a strength of 37-80% by weight. in PFDA solutions containing a solid catalyst from a group of noble metals (Pd / on carbon, Pt / on coal), or water-soluble metal salts of variable valence (e.g. copper, tungsten), or solid metal oxides (e.g. copper), or activated carbon, where the solvent can be either a single-phase non-polar water-insoluble hydrocarbon, or a water-soluble polar (acetonitrile, dimethylformamide), or two-phase, including both, and in particular water ([5], US 6,271,420, publ. August 7, 2001).

The disadvantage of this method is the need for filtering and washing expensive solid catalysts based on noble metals for their reuse, or other solid catalysts with their subsequent disposal, or separation and disposal of water-soluble salts such as sodium tungstate. This is associated with the possibility of environmental pollution, the need for regeneration of solvents, as well as the inconvenience of using the AO obtained by this method in the production of rubber compounds due to their low melting point and the inability to release in a loose final form.

The objective of the present invention is to provide a method for producing such a quinondiimine antioxidant (XDAO), which can be used to charge polymers of solution rubbers and to eliminate leachability and evaporation of known quinondiimine AO during the isolation of solution rubbers.

To solve this problem, a method for producing a quinondiimine antioxidant for solution rubbers is proposed, in which the reaction mixture contains an alkylate obtained by alkylation of 4-aminodiphenylamine with 2-ethylhexanol in the presence of potassium hydroxide at a temperature of 190-235 ° C with distillation of the azeotrope of alcohol with reaction water, containing N-2-ethylhexyl-N'-phenyl-p-phenylenediamine, a 10-19% sodium hypochlorite solution is added uniformly in portions in a ratio of 0.10 to 0.20 mol per 1 mol of N-2-ethylhexyl-N'-phenyl -p-phenylenediamine, while supporting the temperature is about 25 ° C, and after the completion of the dosing of sodium hypochlorite, the resulting reaction mass is washed with water, stirred, sedimented, the aqueous layer is separated from the organic one, the washing and separation of the aqueous layer from the organic layer is repeated twice, after which the target product is isolated from the organic layer, which is a liquid mixture of N-2-ethylhexyl-N'-phenyl-p-quinondiimine and the starting N-2-ethylhexyl-N'-phenyl-p-phenylenediamine with a molar ratio of these compounds in the target product from 10:90 to 20:80 .

Another way to solve this problem is to obtain a quinondiimine antioxidant for solution rubbers, in which the reaction mass is an alkylate obtained by alkylation of 4-aminodiphenylamine with 2-ethylhexanol in the presence of potassium hydroxide at a temperature of 190-235 ° C with distillation of the azeotrope of alcohol with reaction water containing N-2-ethylhexyl-N'-phenyl-p-phenylenediamine, a solution of hydrogen peroxide with a concentration of 10-60% in a ratio of 0.10 to 0.20 mol per 1 mol of N-2-ethylhexyl is introduced in uniform portions of time -N'-phenyl- p-phenylenediamine, while maintaining a temperature of about 20 ° C, after completion of dosing of hydrogen peroxide, the resulting reaction mass is washed with water, stirred, settled, the aqueous layer is separated from the organic, the washing and separation of the aqueous layer from the organic are repeated twice, and then the target is isolated the product from the organic layer, which is a liquid mixture of N-2-ethylhexyl-N'-phenyl-p-quinondiimine and the starting N-2-ethylhexyl-N'-phenyl-p-phenylenediamine with a molar ratio of these compounds to the target m product from 10:90 to 20:80.

The proposed method for the production of quinondiimine antioxidant for rubbers is illustrated by the following examples.

Example 1

In a 500-ml four-necked flask equipped with a stirrer, a water bath, a thermometer and a separatory funnel, 150 g of an uncleaned liquid reaction mass (alkylate) obtained in the first stage of the synthesis of the antioxidant N-2-ethylhexyl-N'-phenyl-p-phenylenediamine-product alkaline condensation of 2-ethylhexanol and 4-aminodiphenylamine, with the content of the main substance (N-2-ethylhexyl-N'-phenyl-p-phenylenediamine) ~ 60% (0.30 mol). Then, while stirring from a dividing funnel of constant pressure, 18.02 ml of aqueous sodium hypochlorite with a concentration of 19.0% (0.06 mol) are dosed dropwise, preventing the temperature rise in the mass above 25 ° C. After completion of the dosing of hypochlorite, water is added to the reaction mass, and salts are washed with stirring. Next, the mixer is stopped and the resulting mass is transferred to a separatory funnel, maintained for separation, the lower aqueous layer is removed, the organic layer is separated, water is added to it and washing is carried out again with stirring. Then repeat the sediment and stratification. The desired product is isolated from the organic layer, which is analyzed by high performance liquid chromatography. Get the content of CDAO in the mass of 17.64 g (0.06 mol), the original AO, N-2-ethylhexyl-N'-phenyl-p-phenylenediamine 71.0 g (0.24 mol).

Example 2

The process is carried out as in Example 1, but into the unwashed liquid alkylate according to Example 1, with the content of the main substance, N-2-ethylhexyl-N'-phenyl-p-phenylenediamine ~ 60% in an amount of 100 g (0.20 mol) at 21.56 ml of aqueous sodium hypochlorite with a concentration of 10.0% (0.034 mol) are dosed dropwise with vigorous stirring from a constant-pressure separatory funnel, preventing the temperature rise in the mass above 25 ° C. After dosing of hypochlorite is completed, water is added to the mixture and the salts are washed with stirring. Then the stirrer is stopped and the resulting mass is transferred to a separatory funnel, kept for delamination, the lower aqueous layer is removed, water is added to the upper organic layer and washing is carried out again with stirring. Then repeat the sediment and stratification. The desired product is isolated from the organic layer, which is analyzed by high performance liquid chromatography. The content of the obtained HDAO in the mass is 10 g (0.034 mol), the starting AO, N-2-ethylhexyl-N'-phenyl-p-phenylenediamine, 49.3 g (0.166 mol).

Example 3

The process is carried out as in Example 1, but into the unwashed liquid alkylate according to Example 1, with the content of the main substance, N-2-ethylhexyl-N'-phenyl-p-phenylenediamine ~ 60% in an amount of 200 g or 0.405 mol with vigorous stirring from 18.9 ml of aqueous sodium hypochlorite with a concentration of 13.5% (0.042 mol) are dosed dropwise into a separatory funnel of constant pressure, preventing the temperature rise in the mass above 25 ° C. After dosing is complete, water is added to the mixture and the salts are washed with stirring. Then the stirrer is stopped and the resulting mass is transferred to a separatory funnel, maintained for separation, the lower aqueous layer is removed, water is added to the upper organic layer / and washing is carried out again with stirring. Then repeat the sediment and stratification. The desired product is isolated from the organic layer, which is analyzed by high performance liquid chromatography. The content of the obtained HDAO in the mass is 11.9 g (0.04 mol) of the starting N-2-ethylhexyl-N'-phenyl-p-phenylenediamine - 107.9 g (0.36 mol).

Example 4

In a 500-ml four-necked flask equipped with a stirrer, a water bath, a thermometer and a separatory funnel, 150 g (~ 150 ml) of unwashed liquid reaction mass (alkylate) according to Example 1, containing the main substance, N-2-ethylhexyl-N'- phenyl-p-phenylenediamine, ~ 60% or 0.30 mol and with vigorous stirring from a separatory funnel, constant pressure, 19.2 g of a 10% aqueous solution of hydrogen peroxide (0.06 mol) are added dropwise, preventing the rise in temperature in the mass above 20 ° C. Then, water is added to the resulting mass and intensively mixed to wash salts. Next, the stirrer is stopped and the resulting mass is transferred to a separatory funnel, maintained for separation, the lower aqueous layer is removed, the organic layer is separated, water is added to it and mixed again. Then repeat the sediment and stratification. The target product is isolated from the organic layer, the analysis of which using high performance liquid chromatography gives a content of the obtained CDAO in the mass of 17.64 g (0.06 mol), of the starting AO, N-ethylhexyl-N'-phenyl-p-phenylenediamine 71.0 g (0.24 mol).

Example 5

The process is carried out as in Example 4, loading an alkylate with a content of the main substance (N-2-ethylhexyl-N'-phenyl-p-phenylenediamine) ~ 60% in an amount of 200 g or 0.405 mol, and with vigorous stirring from a constant pressure dividing funnel 19.8 g of a 12% aqueous solution of hydrogen peroxide (0.07 mol) are added dropwise, preventing the temperature rise in the mass above 20 ° C. Then water is added to the mixture and intensively mixed to wash the salts. Next, the stirrer is stopped and the resulting mass is transferred to a separatory funnel, kept for separation, the lower aqueous layer is removed, the organic layer is separated, water is added to it, mixed, and then the “sediment and separation” is repeated. The target product is isolated from the organic layer, the analysis of which using high performance liquid chromatography gives the content of the obtained CDAO in a mass of 20 g (0.068 mol), the original AO, N-2-ethylhexyl-N'-phenyl-p-phenylenediamine, 98.6 g (0.33 mol).

Example 6

The process is carried out as in Example 4, loading an alkylate containing a basic substance (N-2-ethylhexyl-N'-phenyl-p-phenylenediamine) ~ 60% in an amount of 310.8 g or 0.63 mol and with vigorous stirring from the dividing funnels of constant pressure dropwise dose 16.13 g of a 13.7% aqueous solution of hydrogen peroxide (0.065 mol), preventing the temperature rise in the mass above 20 ° C. Then, water is added to the resulting mass and intensively mixed to wash salts. Next, the mixer is stopped and the resulting mass is transferred to a separatory funnel, maintained for separation, the lower aqueous layer is removed, the organic layer is separated, water is added to it and washing is carried out again with stirring. Then repeat the sediment and stratification. The target product is isolated from the organic layer, the analysis of which using high-performance liquid chromatography will give the content of the obtained CDAO in the mass of 18.5 g (0.063 mol) of the starting N-2-ethylhexyl-N'-phenyl-p-phenylenediamine - 167.9 g (0.567 praying).

In the proposed method for producing CDAO for rubbers using the starting material of the alkylate obtained in the first stage of industrial synthesis of AO rubbers of N-2-ethylhexyl-N'-phenyl-p-phenylenediamine, oxidizing agents from the group consisting of alkali metal percarbonates, organic peroxides and hydroperoxides.

The novelty of the proposed method for producing an antioxidant of the quinondiimine type is determined by its difference from the known methods for producing antioxidants of this type

- using, as a starting material, an intermediate of the alkylation process of 4-aminodiphenylamine with 2-ethylhexanol in the presence of potassium hydroxide,

- lack of use of toxic solvents, as well as additional catalysts.

The conditions for the implementation of the method of obtaining the antioxidant quinondiimine type of the present invention is

- the quantitative ratio of the starting compounds,

- temperature regime of the process,

- the allocation of the target product

- the resulting composition in the target product of N-2-ethylhexyl-N'-phenyl-p-quinondiimine and the starting N-alkyl-N'-phenyl-p-phenylenediamine in a molar ratio of 10:90 to 20:80 respectively eliminates leachability and the evaporation of known quinondiimine AO during the isolation of solution rubbers due to a significantly larger MM (294) obtained by the invention of the CDAO against 266 from a close analogue of N-1,3-dimethylbutyl-N'-phenyl-p-quinondiimine, transfer the process of introducing the quinondiimine AO from the preparation stage rubber compound, where its use is inconvenient due to under tats of the final form (low melting point and the impossibility of obtaining bulk products), at the stage of its introduction into the polymerizate of solution rubbers, introduce into the solution rubbers at the stage of polymerization in the solvents used in the production of solution rubbers, to give the final forms of solution rubbers - briquettes a more uniform color in volume, while providing the opportunity to realize the advantages of rubber compounds with KhDAO and rubber from them, which confirms the solution of the problem and the inventive step of the present invention eniya.

Claims (3)

1. A method of producing a quinondiimine antioxidant for solution rubbers, in which the reaction mass contains an alkylate obtained by alkylation of 4-aminodiphenylamine with 2-ethylhexanol in the presence of potassium hydroxide at a temperature of 190-235 ° C with distillation of an azeotrope of alcohol with reaction water containing N- 2-ethylhexyl-N'-phenyl-p-phenylenediamine, a 10-19% solution of sodium hypochlorite in an amount of from 0.10 to 0.20 mol per 1 mol of N-2-ethylhexyl-N 'contained in the alkylate is uniformly introduced in portions -phenyl-p-phenylenediamine, while maintaining the temperature about at 25 ° C, and after the completion of the dosing of sodium hypochlorite, the resulting reaction mass is washed with water, stirred, sedimented, the aqueous layer is separated from the organic, the washing and separation of the aqueous layer from the organic is repeated twice, after which the target product is isolated from the organic layer, which is a liquid mixture of N-2-ethylhexyl-N'-phenyl-p-quinondiimine and the starting N-2-ethylhexyl-N'-phenyl-p-phenylenediamine with a molar ratio of these compounds in the target product from 10:90 to 20:80. 2. A method of producing a quinondiimine antioxidant for solution rubbers, in which the reaction mixture contains an alkylate obtained by alkylation of 4-aminodiphenylamine with 2-ethylhexanol in the presence of potassium hydroxide at a temperature of 190-235 ° C with distillation of an azeotrope of alcohol with reaction water containing N- 2-ethylhexyl-N'-phenyl-p-phenylenediamine, injected in uniform portions of time a solution of hydrogen peroxide with a concentration of 10-13.7% in an amount of from 0.10 to 0.20 mol per 1 mol contained in alkylate N-2- ethylhexyl-N'-phenyl-p-phenylenediamine, wherein the temperature is maintained at about 20 ° C, after completion of the dosing of hydrogen peroxide, the resulting reaction mass is washed with water, stirred, sedimented, the aqueous layer is separated from the organic, the washing and separation of the aqueous layer from the organic are repeated twice, and then the target product is isolated from the organic layer, which represents a liquid mixture of N-2-ethylhexyl-N'-phenyl-p-quinondiimine and the starting N-2-ethylhexyl-N'-phenyl-p-phenylenediamine with a molar ratio of these compounds in the target product from 10:90 to 20:80. 3. Quinondiimine antioxidant for solution rubbers obtained by the method according to claim 1 or 2.