RU2042664C1 - Di-n-oxides of dialkylbenzene dinitriles as low-temperature rubber hardeners with small unsaturation and a method of synthesis of di-n-oxides of dialkylbenzene dinitriles - Google Patents

Abstract

FIELD: organic chemistry. SUBSTANCE: new di-N-oxides of dialkylbenzene dinitriles. Reagent 1: corresponding dialkylbenzene. Reagent 2: formaldehyde, hydrochloric acid, sulfuric acid, acetic acid. Reaction conditions: reagent 1 is treated with reagent 2 in acid medium at 70-85 C for 5-6 h followed by treatment of prepared product with 10-80% aqueous solution of hexamethylenetetramine at the definite conditions. Then extraction, neutralization and oxidation of prepared product were performed. EFFECT: improved method of synthesis. 4 cl, 6 tbl

Description

где R_1,2=C₂H₅; R₃=C ≡

_→

R_1,2=CH₃; R₃=C ≡

_→

R_1,3=C₂H₅; R₂=C ≡

_→

R_1,3=CH₃; R₂=C ≡

_→

низкотемпературным отвердителям каучуков с малой непредельностью.The invention relates to the chemistry of macromolecular compounds, in particular to derivatives of aromatic nitriles di-N-oxides of dinitriles of dialkylbenzenes of the formula

where R _1,2 = C ₂ H ₅ ; R ₃ = C ≡

_ →

R _1,2 = CH ₃ ; R ₃ = C ≡

_ →

R _1.3 = C ₂ H ₅ ; R ₂ = C ≡

_ →

R _1.3 = CH ₃ ; R ₂ = C ≡

_ →

low temperature rubber hardeners with low unsaturation.

 The invention also relates to a method for producing said substances.

 The invention can be used in the production of elastic rubbers with a wide range of operational characteristics.

 One of the important indicators of the physicochemical properties and chemical composition of known types of natural and synthetic rubbers, along with density, glass transition temperature, medium viscosity mass, impurity content and others, is an indicator of the percentage of unsaturated bonds. According to this parameter, rubbers can be conditionally divided into three groups: group 1 rubbers having a high (up to 48 wt.> C = C <bonds) percent unsaturation, for example, natural rubbers (Smoked Sheets), isoprene (SKI-3) butadiene (SKB), etc.

 The 2nd group of rubbers with low unsaturation (0.2-1.0 wt.> C = C <bonds), for example, butyl rubbers (BK-0845TD, BK-2045N), etc.

3rd group of rubbers with a fully saturated main chain, which can include polyisobutylene (P-155), epichlorohydrin rubbers (SKEHG-200), fluororubber (SKF-260), etc. [1]
Only on the basis of rubbers of the last two groups, elastic polymers were obtained that meet modern requirements with respect to oxidizing agents (ozone, oxygen), the action of heat, with high gas impermeability and resistance to swelling in various oils.

 To obtain elastomers, both with the above and other special properties, various chemical additives (ingredients) are used in the process of vulcanization of rubbers. Among them are vulcanizing agents, accelerators, activators, vulcanization inhibitors, antioxidants, fillers, etc. A special role in this series is played by vulcanizing agents, or polymer hardeners, since they mainly determine the technological parameters of polymer structuring, including temperature conditions.

This leads to substantial energy consumption in the processing of rubbers with low unsaturation have been volumes of their production is a disadvantage of the known hardeners rubbers, for example, sulfur, organic peroxides is the need to use during the curing elevated temperatures usually exceeding 100 ^{° C} [2] tens of thousands of tons per year.

Most old but shirokoprimenyaemy still vulcanizer of sulfur for curing the rubber requires costs a large amount of energy, as only at high temperature (above 150 ° ^C) occurs radical decomposition eight- sulfur cycle t. E. Its activation, followed by a very slow chemical structuring rubber. The complexity of this process increases with the preparation of rubber-based vulcanizates with low unsaturation, since it has been experimentally established that even a slight decrease in unsaturation from 2% to 0.8% (in the case of unsaturation of natural rubbers) reduces the crosslinking rate by almost four times [3] elevated temperatures (in accordance with the Arrhenius dependence) does not always give positive results due to the increased contribution of side reactions of oxidation and pyrolysis.

 Since vulcanization of rubber by elemental sulfur only is a very long high-temperature process, vulcanization accelerators, including various types of carbamates (MN, EN, MC, BC, EFC, DMC, PMP, EEA), thiuram (MM, D, E) are used to intensify it , MT), captax, zincapt, altax, sulfenamides (C, 2C, M, TM, DTM, BT, F) and a number of others, and for polymers with low unsaturation, super accelerators [4] The overwhelming number of the accelerators listed above is reduced mainly , to reduce the time of the vulcanization process and does not change its temperature parameters.

So, the ultra-accelerator for vulcanization of rubber mixtures of piperidinium pentamethylene dithiocarbamate, for example, Carbamat PMP (USSR), Naugatex 144 (US), Pip-Pip (GB), Vulkacit (Ger), allows vulcanization at a temperature not lower than 100-140 ^о С.

Organic peroxides are widely used for vulcanization of rubbers of various nature: di-tert-butyl peroxide (Perbut), dicumyl peroxide (Perkum), benzoyl peroxide (Perbenil). So, for the vulcanization of rubbers with a small unsaturation, for example, organosilicon: (SKTV) di-tert-butyl peroxide is quite effective. The resulting vulcanizates have high hardness and tensile strength. However, in all cases, the vulcanization temperature is in the range 120-170 ^{° C,} wherein the process is conducted for a long time under pressure since its boiling temperature (110 ° ^C) below the temperature to begin its decay structuring [1]
It is also known that for the vulcanization of unsaturated rubbers, and especially rubbers with low unsaturation (butyl rubber, SKEPT), phenol-formaldehyde resins are also used, for example, n-tert-butylphenolformaldehyde resin (Fenofor B), n-tert-Octylphenol formaldehyde resin, ( bromomethylated n-tert-butylphenol formaldehyde resin (Fenofor BB). However, in this embodiment, the curing process of the necessary condition is the temperature of 140-180 ^C. Moreover, according to [1] difficult to obtain good characteristics of the original unsaturation vulcanizates when the rubber below 1.8%, including due to the low crosslinking rate and duration process.

 Known low-temperature curing system of rubbers based on sulfur chloride. However, during the processing of rubbers in the presence of sulfur chloride already in the first 1-2 minutes, “scorching” of the mixture is observed, which makes them unsuitable for further use for the purpose of molding, pressing and does not allow to obtain uniformly crosslinked elastomers. In addition, according to [5], low-temperature curing is permissible only in relation to natural ones, i.e. having a maximum percentage of unsaturation of rubbers, and a significant drawback of this curing system is that hydrochloric acid is released in the process. The specificity of sulfur cure is also that only thin-walled products can be obtained on its basis due to the action in vapors or in a gasoline solution.

Vulcanizing agents include quinone derivatives, for example, n-quinondioxyme (PCDO), which is converted under the action of oxidizing agents, such as lead oxides (IU), into n-dinitrosobenzene, which provides cross-linking at 80-100 ^о С [5] It is known that these agents are explosive components and increase the susceptibility of mixtures to vulcanization, and are now being replaced by phenol-formaldehyde resins. It should be noted the high toxicity of both lead and n-dinitrosobenzene [6]
It is possible to use the products of the interaction of n-benzoquinone dioxime with 2,4,6-very difficult phenols when curing rubbers with low unsaturation of quinol esters. It was with the use of such vulcanizing agents that a significant improvement was achieved in both the technological and operational properties of rubbers based on low-unsaturated butyl rubber [7] Despite the satisfactory results on the properties of the final elastomers and in this curing variant, it is necessary to use elevated temperatures for the structuring process in the range of 100-143 ^about C [8]
Low temperature rubber hardeners with low unsaturation (up to 1.0 wt.) Are unknown.

 No data were found on the di-N-oxides of 1,5-dinitrile-2,4-diethylbenzene, 1,5-dinitrile-2,4-dimethylbenzene, 1,4-dinitrile-2,5-diethylbenzene, 1,4-dinitrile -2,5-dimethylbenzene and their specific properties.

A known method of producing derivatives of aromatic nitriles of polyfunctional N-oxides (terephthalic-bis-nitrile-N-oxide, oxy-bis-4-benzoylcarbonitrile-N-oxide, adipobiscarbonitrile-N-oxide) [9] Thus, in a suspension of 19.8 g oxime terephthalaldehyde in 357 g ester is passed NOCl at ⁰ ° C until disappearance of the green color. After removal of the ether and recrystallization, 5.9 g of terephthalo-bis-oximoyl chloride are obtained with a melting point of 177,5-179 ^C. To a solution of 5 g of the latter in 66 g of methanol was added at ⁰ ° C for 1 hour, a solution of 4.2 g of triethylamine in 1.2 g of methanol. The solid was washed twice with methyl alcohol to give 3.17 g of terephthalo-bis-nitrile-N-oxide. The yield of the target product, calculated on the starting oxime, is about 19.0 wt. (from theor.). It should be noted that the starting oxime requires a separate synthesis, which, of course, means a further decrease in the yield of the final compound. The low yield of N-oxides and the absolute production conditions are an obstacle to the use of the known method for the synthesis of derivatives of aromatic nitriles in practice.

C=C

связей). Действие отвердителей не распространяется на каучуки с малой непредельностью. Кроме того, область потенциального использования этих отвердителей ограничена тем, что процесс отверждения протекает в присутствии растворителя (бензола) и поэтому проведение структурирования в "массе" невозможно.Obtained in known manner polyfunctional N-oxides have been tested as a low-temperature (25 ° ^C) hardeners cis-1,4-polybutadiene, high Unsaturated rubber (48 wt.

C = c

connections). Hardeners do not apply to rubbers with low unsaturation. In addition, the area of potential use of these hardeners is limited by the fact that the curing process proceeds in the presence of a solvent (benzene) and therefore the structuring in the mass is impossible.

There is also a method for producing derivatives of aromatic nitriles-polyfunctional N-oxides from aromatic aldehydes of derivatives of mesitylene, durene and 1,3,5-triethylbenzene [10]
The synthesis of N-oxides includes the steps of oximedialdehydes and subsequent oxidation of dioximes in the target product.

H₅

H₅

H

C

H

К раствору 0,1 моля диальдегида в 300-400 мл этилового спирта прибавляли последовательно при 50^оС растворы 0,4 моля NaOH в 20 мл H₂О и 0,4 моля NH₂OHxHCl в 50 мл Н₂О. Реакционную массу кипятили 4 ч. растворитель отгоняли, остаток обрабатывали 50-100 мл СHCl₃ в 100 мл Н₂О, отделяли органический слой и промывали его водой (3х200 мл). После отгонки СНСl₃ остаток перекристаллизовывали из гексана. Т.пл. 122-123,5^оС. Выход 74% (от теор.).So, 2,4,6-triethylisophthalodinitrile oxide was obtained according to the following scheme:
H

H ₅

H ₅

H

C

H

To a solution of 0.1 mole of the dialdehyde in 300-400 ml of ethanol were added successively ^at 50 ° C solution of 0.4 mole of NaOH in 20 ml H ₂ O and 0.4 mol NH ₂ OHxHCl in 50 ml H ₂ O. The reaction mixture was heated For 4 hours, the solvent was distilled off, the residue was treated with 50-100 ml of CHCl ₃ in 100 ml of H ₂ O, the organic layer was separated and washed with water (3 × 200 ml). After distillation of CHCl _{3, the} residue was recrystallized from hexane. Mp 122-123.5 ^about C. Yield 74% (of theory).

To a vigorously stirred and cooled to 5-7 ^{° C} an aqueous solution of 0.5 mol of 10-15% sodium hypochlorite containing 8-10% NaOH, 5-10 minutes, added a solution of 0.1 mole in 150-250 ml dioxime _CH2 Cl ₃ . The mixture was vigorously stirred for 1 hour while gradually raising the temperature ^to 15 ° C, the organic layer was separated and the aqueous extracted with CH ₂ Cl ₃ (2x50 mL). The combined organic layer was washed with water (4 x 100 ml) and, after distilling off the solvent in vacuo, the residue was recrystallized from hexane. Mp 93-96 ^about C. The yield of dioxide 75% (from theory.). (Based on oxime or about 38% based on intermediate (dichloromethyl) -formyl triethylbenzene [10, 11]).

The starting compounds for this synthesis were obtained by dialdehydes by formylation under absolute conditions of the corresponding alkylbenzenes with (dichloromethyl) methyl ether in the presence of AlCl ₃ or TiCl ₄ [11]
As a result of the implementation of the known method, N-oxides capable of reacting a 1,3-dipolar cycloaddition with substances containing multiple bonds, i.e. potentially capable of acting as rubber hardeners. However, in the analyzed source [10] there is no specific information about hardeners based on the obtained N-oxides.

 The disadvantages of this method are the multi-stage preparation of the target product, which reduces its yield based on the starting mesitylene, durene, 1,3,5-triethylbenzene and, ultimately, makes it unpromising from a practical point of view. In addition, synthesis reagents are difficult to access and impractical from an environmental point of view. Products obtained at each stage require thorough cleaning.

 The purpose of the invention is to reduce the temperature of the vulcanization process and, therefore, to reduce the level of energy consumption in the production of rubbers with low unsaturation.

где R_1,2=C₂H₅; R₃=C ≡

_→

R_1,3=CH₃; R₂=C ≡

_→

R_1,3=C₂H₅; R₂=C

N

O
R_1,3= CH₃; R₂=C ≡

_→

в качестве низкотемпературных отвердителей каучуков с малой непредельностью и специально разработанный способ их получения, который реализуется следующей совокупностью существенных признаков:
на первой стадии синтеза проводят реакцию селективного бис-хлорметилирования исходного диалкилбензола в кислой среде, содержащей формальдегид, соляную кислоту, серную кислоту, уксусную кислоту, взятых в мольных соотношениях диалкилбензол: формальдегид соляная кислота серная кислота уксусная кислота 1,0 (2,5-3,2) (2,2-3,2) (6,0-14,0) (2,0-4,5) при 70-85^оС в течение 2-5 ч;
в качестве диалкилбензола используют 2,4-диэтилбензол, 2,4-диметилбензол, 2,5-диэтилбензол, 2.5-диметилбензол;
на второй стадии последовательно обрабатывают полученный бис(хлорметил)-диалкилбензол 10-80% -ным водным раствором гексаметилентетрамина, взятого в мольном соотношении бис(хлорметил)-диалкилбензол гексаметилентетрамин 1: (2-4) в течение 1-2 ч при температуре кипения и 10-80%-ной водной уксусной кислотой в течение 2-5 ч при нагревании до кипения, с последующей экстракцией продуктов реакции органическим растворителем из ряда хлоралканов и обработкой полученного экстракта гидроксиламином, взятом в мольном соотношении бис(хлорметил)-диалкилбензол гидроксиламин 1:(2-3) при рН 6-8 в течение 0,5-1 ч при 25-50^оС, добавлением водной натриевой щелочи для получения рН 12-14, отделением органического растворителя с последующей нейтрализацией водного раствора 6-7 и выделением соответствующего диоксима диальдегида диалкилбензола;
на третьей стадии проводят окислительное хлорирование диоксима 5-15%-ным водным раствором гипохлорита натрия в течение 0,5-1 ч при рН 6-10 и температуре (-10)-(+10)^оС с получением целевого соединения.The essence of the invention lies in the fact that proposed new substances di-N-oxides of dinitriles of dialkylbenzenes of the formula

where R _1,2 = C ₂ H ₅ ; R ₃ = C ≡

_ →

R _1.3 = CH ₃ ; R ₂ = C ≡

_ →

R _1.3 = C ₂ H ₅ ; R ₂ = C

N

O
R _1.3 = CH ₃ ; R ₂ = C ≡

_ →

as low-temperature hardeners of rubbers with low unsaturation and a specially developed method for their preparation, which is implemented by the following set of essential features:
at the first stage of the synthesis, a selective bis-chloromethylation reaction of the starting dialkylbenzene is carried out in an acidic medium containing formaldehyde, hydrochloric acid, sulfuric acid, acetic acid, taken in molar ratios of dialkylbenzene: formaldehyde hydrochloric acid sulfuric acid, acetic acid 1.0 (2.5-3 , 2) (2,2-3,2) (6,0-14,0) (2,0-4,5) at 70-85 ^{° C} for 2-5 hours;
2,4-diethylbenzene, 2,4-dimethylbenzene, 2,5-diethylbenzene, 2.5-dimethylbenzene are used as dialkylbenzene;
in the second stage, the obtained bis (chloromethyl) -dialkylbenzene is successively treated with a 10-80% aqueous solution of hexamethylene tetramine taken in a molar ratio of bis (chloromethyl) dialkylbenzene hexamethylenetetramine 1: (2-4) for 1-2 hours at the boiling point and 10-80% aqueous acetic acid for 2-5 hours when heated to boiling, followed by extraction of the reaction products with an organic solvent from a number of chloralkanes and treatment of the obtained extract with hydroxylamine, taken in a molar ratio of bis (chloromethyl) dialkylbenzene idroksilamin 1: (2-3) at pH 6-8 for 0.5-1 hours at 25-50 ^{° C,} by addition of aqueous sodium hydroxide to obtain a pH of 12-14, separating the organic solvent followed by neutralization with an aqueous solution 6-7 and the selection of the corresponding dialkyl dialdehyde dioxide dioxylbenzene;
in the third stage, oxidative chlorination of dioxime is carried out with a 5-15% aqueous solution of sodium hypochlorite for 0.5-1 hours at a pH of 6-10 and a temperature of (-10) - (+ 10) ^о С to obtain the target compound.

PRI me R 1. To 33.7 g (30.9 ml; 392 mmol) of 35% aqueous formalin at room temperature with stirring 40.9 g (34.9 ml; 392 mmol) 36 are added sequentially, 36 5% hydrochloric acid and 16.5 g (15.7 ml; 275 mmol) of concentrated acetic acid. Next, 17.6 g (20.4 ml; 131 mmol) of 2,4-diethylbenzene are added to the obtained acid mixture at the indicated temperature and 90.2 g (50 ml; 920 mmol) of 94.5% are metered in over 25-30 minutes sulfuric acid (the ratio of the reagents are given in table 2). The reaction mixture was heated to ⁷⁰ ° C and kept under stirring for 3 hours. After aging the reaction products are cooled to 15-25 ^{° C,} the precipitated crystals were 1,5-bis (chloromethyl) -2,4-diethylbenzene is filtered, washed on the filter water (2x100 ml), 3% sodium bicarbonate solution (2x50 ml) to a pH of washings of 6-7, water (2x100 ml) and dried to constant weight. Obtain 29.7 g (98% of theory.) Bis-chloromethyl derivative of 2,4-diethylbenzene, which is used without further processing for subsequent synthesis. In order to characterize the obtained compound by crystallization from alcohol, a sample was obtained with mp 63-66 ^about S.

 Calculated, C 62.33; H 6.93; Cl 30.74.

Found, C, 62.54; 62.26; H 7.02; 7.12; Cl 30.46; 30.93;
Mol.m. (mass spectrometric): 231.

The IR spectrum contains absorption bands characteristic of the chloromethyl group, cm ^-1 : C-Cl 1250; 650.

PMR spectrum (chloroform -d ₃ );
Triplet 1.07; 1.14; 1.22 (6H, CH ₃ );
Quartet 2.48; 2.56; 2.62; 2.70 (4H, CH ₂ );
Singlets 4.38 (4H, CH ₂ Cl);
6.88; 7.08 (2H, aromatic).

To a solution of 25.2 g (180 mmol) of hexamethylenetetramine in 20 ml of water was added 13.9 g (60 mmol) of 1,5-bis (chloromethyl) -2,4-diethylbenzene (reagent ratios are given in table 3). The reaction mass is heated up to 95-100 ^C and kept for 1 hour, then added 45 ml of concentrated acetic acid and kept at 95-100 ^{° C} for 3 hours. From the reaction mixture the organic products extracted with carbon tetrachloride (2h35 ml) the extract is washed with 100 ml of water. 30 ml of water are added to the washed extract. With stirring, 10.5 g (80 mmol) of hydroxylamine hydrochloride are added. The mixture was neutralized with a solution of 4 g (100 mol) NaOH in 10 ml water to pH 7-9 and kept at 25-35 ^{° C} for 30 min. Next, a solution of 14 g (350 mmol) NaOH in 40 ml water (pH> 12) and make the shutter 30 min at 25-35 ^C. The organic layer was separated. The aqueous layer was cooled to 20 ° ^C and neutralized with hydrochloric acid to pH 7. The separated precipitate dioxime 1,5-dialdehyde-2,4-diethylbenzene was filtered off, washed on filter with water (2x50 mL) and dried in air until constant weight. Obtain 7.5 g (57%) of dioxime 1,5-dialdehyde-2,4-diethylbenzene with so pl. 156-160 ^about C. Without additional purification, dioxime can be used to obtain N-oxide.

 Calculated, C 65.45; H 7.27; N, 12.73.

 Found, C, 65.32; 65.21; H 7.53; 7.70; N, 12.38; 12.65.

 Mol.m. (mass spectrometric): 220.

The IR spectrum contains absorption bands characteristic of the oxime group, cm ^-1 : 3300 (OH); 1610 (C = N); 950, 970 (N-OH).

PMR spectrum (chloroform -d ₃ ):
Triplet 1.07; 1.14; 1.22 (6H, CH ₃ );
Quartet 2.58; 2.66; 2.73; 2.81 (4H, CH ₂ );
Singlets 6.93 (2H, CHN);
7.86; 8.16 (2H, aromatic).

Concentrated hydrochloric acid is added to 60 ml of a 100% aqueous sodium hypochlorite solution (81 mmol) with stirring to pH 7-9, and then 7.9 g (39 mmol) of finely divided 1,5-dialdehyde-2,4-diethylbenzene dioxime at (-10) -0 ^{° C} for 40 min. The reaction mass is maintained at this temperature for 35 minutes. The precipitated crystalline product is filtered off, washed on a funnel with water (3x50 ml) and dried in air to constant weight. 7 g (90% yield) of 1,5-dinitrile-2,4-diethylbenzene di-N-oxide are obtained. T.n. 85-89 ^about With (according to derivatography).

 Calculated, C 66.67; H 5.56; N, 12.96.

 Found, C, 66.78; 66.85; H 5.42; 5.39; N 13.05; 13.10.

 Mol.m. (mass spectrometric): 216.

The IR spectrum contains bands characteristic of the nitrile oxide group, cm ^-1 : 2310, 1340.

PMR spectrum (chloroform -d ₃ ):
Triplet 1.07; 1.14; 1.22 (6H, CH ₃ );
Quartet 2.66; 2.72; 2.87; 2.90 (4H, CH ₂ );
Singlets 7.96; 8.86 (2H, aromatic).

 Di-N-oxides of 1,5-dinitrile-2,4-dimethylbenzene, 1,4-dinitrile-2,5-diethylbenzene, 1,4-dinitrile-2,5-dimethylbenzene were obtained analogously to the example.

 The properties of these dinitrile oxides are summarized in table. 1, which characterizes the physicochemical properties of the intermediate and final synthesis products.

 Table 2 illustrates the effect of individual synthesis parameters on the yield of intermediate bis (chloromethyl) dialkylbenzenes.

As can be seen from the data of Table 2, a deviation from the optimal parameters of selective bis-chloromethylation indicated in the claims leads to a decrease in the yield of intermediate bis (chloromethyl) dialkylbenzenes, which is confirmed, for example, by the results obtained both with a decrease and an increase in the molar ratio DAB: formalin: HCl: H ₂ SO ₄ : CH ₃ COOH (see options 2.3; 4.5; 6.7; 8.9).

 Table 3 illustrates the effect of individual synthesis parameters on the output of intermediate dialdehyde dialkylbenzenes.

 As can be seen from the data in Table 3, a deviation from the optimal parameters of the second stage of the process leads to a decrease in the yield of intermediate dioxides of dialdehyde dialkylbenzenes.

Tab. 4 illustrates the results of comparative tests of the curing action of 1,5-dinitrile-2,4-diethylbenzene di-N-oxide and conventional curing systems with respect to various types of rubbers with low unsaturation
Tab. 5 illustrates the results of comparative tests of the curing action of 1,4-dinitrile-2,5-diethylbenzene di-N-oxide and conventional curing systems with respect to various types of rubbers with low unsaturation.

 Table 6 illustrates the results of comparative tests of the curing effect of di-N-oxides of 1,5-dinitrile-2,4-dimethylbenzene and 1,4-dinitrile-2,5-dimethylbenzene, and traditional curing systems with respect to various types of rubbers with low unsaturation.

 As can be seen from tables 4, 5 and 6, the invention allows to solve the problem of reducing the temperature of the vulcanization process and, consequently, reducing energy consumption in the production of rubbers through the use of new low-temperature hardeners of di-N-oxides of dialkylbenzenes dinitriles obtained by a method suitable for implementation in industry . The rubbers obtained using the new low-temperature hardeners are not inferior in terms of physical and mechanical properties, and the rubbers obtained using traditional multicomponent high-temperature hardeners are superior in elasticity.

 The proposed method for the production of di-N-oxides of dinitriles of dialkylethylbenzenes meets the requirements of the chemical industry for new technologies.

 Unlike the analogue and prototype, the substances used in the synthesis of the starting dialkylbenzenes, aqueous formalin, acids, urotropine, carbon tetrachloride are technical products widely produced by the chemical industry.

 The proposed synthesis method is superior to the analogue and prototype in the yield of the final product.

The yield of N-oxide is as follows: an analog of less than 19 wt. (based on the starting oxime, taking into account its synthesis, the yield of the final product will significantly decrease);
prototype about 38 wt. (based on intermediate (dichloromethyl) formyltriethylbenzene [4, 5]
based on alkylbenzene will further reduce the yield of the corresponding N-oxide);
the invention of 50 wt. (based on the starting alkylbenzene).

 Considering the fact that ecology and recycling of industrial waste are currently of priority importance, the proposed synthesis method allows for the complete recycling of acetic acid and organic solvent used in the process using traditional chemical technology (simple distillation or distillation). This creates the prerequisites for creating a completely closed technological process, provided that the issue of regeneration of the spent acid mixture at the stage of selective bis-chloromethylation is solved, which can be achieved by saturating it with available sulfuric anhydride. Excess reagents are close to theoretical, which determines the efficiency of the synthesis method.

The intervals of temperature variation (-10) - (+ 105) ^о С and the process time in separate stages (3 h, 10 h, 1 h) and in general (14 h) are usual and do not require special technological design.

 From the point of view of a chemical technologist, it is important that the proposed synthesis method not only allows to achieve high quality semi- and target products, but also maximally relates the technological parameters of individual stages (during the synthesis, there is no need for irrational intermediate drying or additional impractical recrystallization) .

Claims (3)

1. Di-N-oxides of dinitriles of dialkylbenzenes of the General formula

1. R ₁ , R ₂ = C ₂ H ₅ ; R ₃ = C ≡ N _ → O;
2. R ₁ , R ₂ = CH ₃ ; R ₃ = C ≡ N _ → O;
3. R ₁ , R ₂ = C ₂ H ₅ ; R ₂ = C ≡ N _ → O;
4. R ₁ , R ₃ = CH ₃ ; R ₂ = C ≡ N _ → O,
as low temperature rubber hardeners with low unsaturation. 2. The method of obtaining di-N-oxides of dinitriles of dialkylbenzenes of the General formula

where 1. R ₁ , R ₂ = C ₂ H ₅ ; R ₃ = C ≡ N _ → O;
2. R ₁ , R ₂ = CH ₃ ; R ₃ = C ≡ N _ → O;
3. R ₁ , R ₃ =; R ₂ = C ≡ N _ → O;
4. R ₁ , R ₃ = CH ₃ ; R ₂ = C ≡ N _ → 0,
characterized in that the corresponding dialkylbenzene is subjected to selective bis-chloromethylation in an acidic medium containing formaldehyde, hydrochloric acid, sulfuric acid, acetic acid with a molar ratio of dialkylbenzene: formaldehyde: hydrochloric acid: sulfuric acid: acetic acid, equal to 1.0 2.5 + 3.2 2.2 + 3.2 6.0 14.0 2.0 4.5, at 70 + 85 ^o C for 2 5 hours, the corresponding bis (chloromethyl) dialkylbenzene obtained is treated with 10 80% aqueous solution of hexamethylenetetramine in a molar ratio of bis (chloromethyl) dialkylbenzene, hexame ilentetramine 1.0 2 4 for 1 2 hours at boiling point and 20 80% aqueous acetic acid for 2 5 hours while boiling, the product obtained is extracted with an organic solvent selected from a number of chloralkanes, the extract is treated with hydroxylamine in a molar ratio bis- (chloromethyl) dialkylbenzene: hydroxylamine, respectively, equal to 1 2 3, at pH 6 8 for 0.5 1 h at 25 + 50 ^o С, add an aqueous solution of sodium hydroxide to obtain a pH of 12 14, separate the organic solvent, neutralize the aqueous acid solution to pH 6 8 to obtain the corresponding dioxime, which is subjected to oxidation with sodium hypochlorite in an alkaline medium at a temperature of 10 10 ^o C.  3. The method according to claim 2, characterized in that 2,4-diethylbenzene, 2,4-dimethylbenzene, 2,5-diethylbenzene, 2,5-dimethylbenzene are used as dialkylbenzene.

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