Preparation method and system of anti-aging agent TMQ

Abstract

The invention relates to the field of rubber additives, and discloses a preparation method and system of an anti-aging agent TMQ. The method comprises the following steps: (1) in the presence of a hydrochloric acid catalyst, carrying out condensation polymerization on aniline and acetone to obtain a TMQ condensation polymerization liquid; (2) separating the obtained TMQ polycondensation liquid to respectively obtain a light component and a heavy component, and controlling the molar ratio of aniline to the hydrochloric acid catalyst in the heavy component; (3) filtering the obtained heavy component to obtain a filtrate which is a TMQ reaction liquid, and returning the obtained filter cake to the condensation polymerization in the step (1); and (4) adding the obtained TMQ reaction liquid into liquid caustic soda for neutralization, and distilling the obtained oil phase to obtain the anti-aging agent TMQ. Light components and heavy components in the TMQ polycondensation reaction liquid are separated, and the molar ratio of aniline to the hydrochloric acid catalyst in the heavy components is controlled, so that the hydrochloric acid catalyst is conveniently filtered and separated from the heavy components, and a large amount of hydrochloric acid is reused for catalytic reaction.

Description

Technical Field

[0001] The invention relates to the field of rubber additives, and in particular to a preparation method and system of an antioxidant TMQ. Background Art

[0002] Antioxidant TMQ is a mixture of di-, tri- and tetra-polymers of 2,2,4-trimethyl-1,2-dihydroquinoline, also known as antioxidant RD. It is mainly used as an antioxidant for rubber and rubber products. It is suitable for natural rubber, synthetic rubber and latex. It has a strong inhibitory effect on the catalytic oxidation of harmful metal ions such as copper and manganese. It has good compatibility with rubber, low volatility, low frosting and high extraction resistance. It is widely used by rubber processing industries at home and abroad. Whether it is ordinary tires, radial tires or other rubber products, it needs to be added to achieve better protective performance.

[0003] The general production process of the antioxidant TMQ is as follows: aniline and hydrochloric acid are dehydrated to obtain aniline hydrochloride; aniline hydrochloride and acetone are subjected to condensation reaction to obtain TMQ condensation liquid; the condensation liquid is neutralized and water is separated by adding liquid alkali; then the oil phase is distilled and granulated to obtain the TMQ finished product.

[0004] CN108003095A discloses a commonly used production method of TMQ: 1) Intermittent kettle method: the raw material aniline and the catalyst are put into the kettle at one time, and acetone is fed by continuous dripping, and the feeding reaction time is generally 2-7 hours. Under normal pressure, the reaction temperature is controlled to be 90-150°C, and the acetone is directly separated and recovered by the fractionation tower on the reactor, and then the acetone is applied to the raw material storage tank. 2) Continuous tower method: aniline and catalyst titanate are continuously fed from the top of the tower, and acetone is fed from the gas phase at the bottom of the tower after vaporization, and continuous reaction is carried out in the tower. Under normal pressure, the reaction temperature is controlled to be 90-150°C. The material stays in the tower for 3-7 hours. Acetone and water generated during the reaction are simultaneously evaporated, and then the acetone is directly separated and recovered by the fractionation tower, and the antioxidant TMQ polycondensation reaction liquid generated by the reaction continuously flows into the receiving tank at the bottom of the tower. Add liquid alkali to neutralize the TMQ polycondensation liquid in the reactor or receiving tank, let it stand for stratification, and distill the oil phase under a vacuum of -0.098MPa with the material temperature controlled at 180-260℃. After the kettle material is cooled, it is granulated to obtain the antioxidant TMQ finished product.

[0005] CN103539962A discloses a method for preparing a low-amine rubber antioxidant TMQ. Aniline and hydrochloric acid are added to a reactor, stirred and heated to 130°C, stirred for 30 minutes, and the amount of hydrochloric acid used is 6-10% of the weight of the aniline; 2,2,4-trimethyl-1,2-dihydroquinoline monomer is added to the reactor, and the added amount is 70-80% of the mass of the aniline. When the temperature is controlled at 120-125°C, acetone is continuously added dropwise, and the mass ratio of aniline to acetone is 1:1-4. The adding time and temperature are controlled. After the addition is completed, the temperature is maintained at 140°C and maintained for 4 hours; heating is stopped and sodium hydroxide aqueous solution is added, stirred for 30 minutes, and the pH value is controlled to be 11 after neutralization, and then allowed to stand for 60 minutes; the aqueous phase is separated and removed to obtain an organic phase; the monomer is distilled off under vacuum to obtain an antioxidant TMQ product.

[0006] Due to the use of environmentally friendly processes such as molecular sieves and solid acids, it is not yet mature, and there are problems such as unstable operation and high cost. At present, the production method of antioxidant TMQ at home and abroad mainly uses hydrochloric acid as a catalyst to carry out polycondensation reaction of aniline and acetone. Its main characteristics are simple synthesis method, short process and mature process. The disadvantage is that the hydrochloric acid catalyst cannot be reused and requires a large amount of liquid alkali for neutralization, thereby generating high-salt wastewater with a salt (sodium chloride) content of up to 10-18% and containing a large amount of organic matter. The high-salt wastewater cannot be directly used, and is difficult to handle or has poor economic efficiency, thus bringing environmental protection problems. Summary of the invention

[0007] The purpose of the present invention is to overcome the problems in the prior art that the hydrochloric acid catalyst cannot be reused, a large amount of liquid alkali is required for neutralization, and a large amount of high-salt wastewater with organic matter is produced, and a method and system for preparing an antioxidant TMQ are provided.

[0008] In order to achieve the above object, the first aspect of the present invention provides a method for preparing an antioxidant TMQ, wherein the method comprises:

[0009] (1) in the presence of hydrochloric acid catalyst, aniline and acetone are subjected to polycondensation reaction to obtain TMQ polycondensation liquid;

[0010] (2) separating the obtained TMQ polycondensation liquid to obtain a light component and a heavy component, respectively, while controlling the molar ratio of aniline to the hydrochloric acid catalyst in the heavy component;

[0011] (3) filtering the obtained heavy components, the obtained filtrate is the TMQ reaction liquid, and the obtained filter cake is returned to the polycondensation reaction in step (1);

[0012] (4) adding liquid alkali to neutralize the obtained TMQ reaction solution, and distilling the obtained oil phase to obtain the antioxidant TMQ.

[0013] The second aspect of the present invention provides a preparation system for the antioxidant TMQ, wherein the system comprises: a condensation polymerization reaction device and a separation device connected in sequence; a filtering device and a recovery device connected to the separation device, a neutralization device connected to the filtering device, and a distillation device connected to the neutralization device; wherein the filtering device and the recovery device are also each connected to the condensation polymerization reaction device.

[0014] Through the above technical scheme, the present invention separates the light components and heavy components in the TMQ polycondensation reaction liquid, controls the molar amount of aniline in the heavy components during the separation process, and facilitates the filtration and separation of the hydrochloric acid catalyst from the heavy components, thereby recycling a large amount of hydrochloric acid for the catalytic reaction, and does not require a large amount of liquid alkali neutralization, reducing the amount of high-salt wastewater by more than 97%. The content of di-, tri-, and tetramers of the effective component 2,2,4-trimethyl-1,2-dihydroquinoline in the TMQ finished product is greater than 50%, the harmful component IBA (isopropyl diphenylamine) is less than 0.5%, and the softening point is 86-97°C. Therefore, in the subsequent continuous production process, the amount of high-salt wastewater generated by acid-base neutralization is reduced by more than 97%, which is a green and environmentally friendly synthesis process. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The invention provides a system for preparing an antioxidant TMQ.

[0016] Description of Reference Numerals

[0017] 1. Polycondensation reaction device; 2. Separation device; 3. Recovery device; 4. Filtration device; 5. Neutralization device; 6. Distillation device DETAILED DESCRIPTION

[0018] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0019] The first aspect of the present invention provides a method for preparing an antioxidant TMQ, wherein the method comprises:

[0020] (1) in the presence of hydrochloric acid catalyst, aniline and acetone are subjected to polycondensation reaction to obtain TMQ polycondensation liquid;

[0021] (2) separating the obtained TMQ polycondensation liquid to obtain a light component and a heavy component, respectively, while controlling the molar ratio of aniline to the hydrochloric acid catalyst in the heavy component;

[0022] (3) filtering the obtained heavy components, the obtained filtrate is the TMQ reaction liquid, and the obtained filter cake is returned to the polycondensation reaction in step (1);

[0023] (4) adding liquid alkali to neutralize the obtained TMQ reaction solution, and distilling the obtained oil phase to obtain the antioxidant TMQ.

[0024] In the present invention, the light component and the heavy component in the TMQ polycondensation reaction liquid are separated. During the separation process, the molar ratio of aniline to the hydrochloric acid catalyst in the heavy component is controlled to be 0.3-2:1, so that a large amount of organic hydrochloride enters the heavy component and precipitates. Then, filtering is performed and the filtering conditions are controlled. The obtained filter cake contains a large amount of organic hydrochloride, which can be directly reused in the polycondensation reaction in step (1), thereby reusing a large amount of hydrochloric acid for the catalytic reaction, without the need to use a large amount of liquid alkali for neutralization, and reducing the amount of high-salt wastewater by more than 97%.

[0025] In some specific embodiments of the present invention, in step (1), the molar ratio of aniline, acetone and hydrochloric acid catalyst is 1:1.5-10:0.05-0.5.

[0026] In some specific embodiments of the present invention, in step (1), the time of the polycondensation reaction is 0.001-10 h, and the temperature of the polycondensation reaction is 90-200°C.

[0027] In some specific embodiments of the present invention, in step (2), the separation is selected from distillation, rectification or fractional distillation.

[0028] In some specific embodiments of the present invention, in step (2), the light component contains 10-40wt% acetone, 10-40wt% water, 5-20wt% aniline and 0-30wt% other impurities. By controlling the separation and refining conditions of the light component, the aniline and acetone are separated to the greatest extent, so that the aniline and acetone are returned to the polycondensation reaction, thereby realizing the recycling of raw materials.

[0029] In some specific embodiments of the present invention, the light component is separated and refined and then returned to the polycondensation reaction in step (1) as a recycled raw material.

[0030] In some specific embodiments of the present invention, the separation and refining of the light component includes: first controlling the separation conditions to normal pressure, the gas phase temperature to 0-120°C, separating and recovering acetone and a small amount of impurities (amine, water, mesityl oxide); then controlling the separation conditions to normal pressure or reduced pressure, under normal pressure conditions, the gas phase temperature is 121-220°C, and when the reduced pressure conditions are 1-200Pa, the gas phase temperature is 0-90°C, separating and recovering aniline and a small amount of impurities (acetone, water, 2,2,4-trimethyl-1,2-dihydroquinoline and dimers and polymers, isopropyl diphenylamine, etc.), and the obtained acetone and aniline are returned to the polycondensation reaction as raw materials. The separation and refining conditions of the light component of the present invention can separate the acetone and aniline remaining in the polycondensation reaction and return them to the polycondensation reaction, thereby realizing the recycling of raw materials and reducing the waste of raw materials.

[0031] In some specific embodiments of the present invention, the separation and purification of the heavy component includes: the separation condition is normal pressure or reduced pressure, under normal pressure conditions, the gas phase temperature is 0-220°C, and the heavy component is separated; when the reduced pressure condition is 1-500Pa, the gas phase temperature is 0-90°C, and the heavy component is separated.

[0032] In some specific embodiments of the present invention, in step (2), by controlling the process conditions of separation, the separation conditions are atmospheric pressure or reduced pressure, under atmospheric pressure, the gas phase temperature is 0-220°C, and the heavy component is separated; when the reduced pressure condition is 1-500 Pa, the gas phase temperature is 0-90°C, and the heavy component is separated, and the aniline content in the heavy component is detected at the same time, and the molar ratio of aniline to the hydrochloric acid catalyst in the heavy component is controlled to be 0.3-2:1, for example, 0.5:1, 0.6:1, 0.8:1, 1:1, 1.2:1, 1.4:1, 1.8:1, and any value in the range of any two values, preferably 0.9-1.1:1. By controlling the molar ratio of aniline to the hydrochloric acid catalyst in the heavy component, aniline and other organic substances form salts with hydrochloric acid within this range, the solubility of hydrochloric acid in the system is minimal, and it is easiest to filter and separate from the heavy component, so that more salt is returned to the polycondensation reaction in the filter cake through filtration, and the obtained TMQ reaction liquid contains less salts, and the amount of liquid alkali required for neutralization is greatly reduced, thereby greatly reducing the amount of salt-containing wastewater.

[0033] In some specific embodiments of the present invention, the heavy component contains 5-20wt% of 2,2,4-trimethyl-1,2-dihydroquinoline, 20-60wt% of TMQ, 0.5-10wt% of aniline, 0.5-2wt% of isopropyl diphenylamine, 1-10wt% of aniline hydrochloride, 0.5-2wt% of isopropyl diphenylamine hydrochloride, 0.5-5wt% of 2,2,4-trimethyl-1,2-dihydroquinoline pentamer, 0.1-2wt% of hexamer, and 0-30wt% of other impurities. The other impurities may be one or more of the following structural formulas: When the content of the heavy component is controlled within the above range, the amount of organic hydrochloride formed is the largest, and the hydrochloric acid is most easily separated from the heavy component by filtration, so that more salt is filtered and stored in the filter cake and returned to the polycondensation reaction.

[0034] In some specific embodiments of the present invention, in step (3), the filtration temperature is 80-150° C. By controlling the filtration temperature, the solubility of the crystals is reduced and the TMQ reaction solution can be prevented from solidifying and clogging the system. The size of the crystals can be controlled by filtering through a filter with a pore size of 1-5 microns.

[0035] In some specific embodiments of the present invention, in step (3), the filter cake contains aniline hydrochloride, 2,2,4-trimethyl-1,2-dihydroquinoline hydrochloride, TMQ hydrochloride and propyl diphenylamine hydrochloride. By controlling the molar ratio of aniline in the heavy component to the hydrochloric acid catalyst, within this range, organic substances such as aniline and hydrochloric acid form salts, and the solubility of hydrochloric acid in the system is minimal, and it is easiest to filter and separate from the heavy component, so that more salt is filtered and stored in the filter cake and returned to the polycondensation reaction.

[0036] In some specific embodiments of the present invention, in step (3), preferably, the filter cake is added with hydrochloric acid and then returned to the polycondensation reaction, and the amount of hydrochloric acid added satisfies the molar ratio of aniline, acetone and hydrochloric acid catalyst in step (1) of 1:1.5-10:0.05-0.5. Alternatively, the filter cake may be returned to the polycondensation reaction without adding hydrochloric acid.

[0037] In some specific embodiments of the present invention, in step (3), the TMQ reaction solution contains: 5-25wt% of 2,2,4-trimethyl-1,2-dihydroquinoline, 20-65wt% of TMQ, 0.01-15wt% of aniline, 0.01-2.5wt% of isopropyl diphenylamine, 0.01-2wt% of aniline hydrochloride, 0-0.5wt% of isopropyl diphenylamine hydrochloride, 0.5-8wt% of 2,2,4-trimethyl-1,2-dihydroquinoline pentamer, 0.1-4wt% of hexamer, and 0-30wt% of other impurities. It can be seen from the above components that the amount of organic hydrochloride in the TMQ reaction solution obtained by filtration is small, and by controlling the molar ratio of aniline in the heavy component to the hydrochloric acid catalyst, most of the salt has been filtered and stored in the filter cake and returned to the polycondensation reaction, thereby realizing the recycling of hydrochloric acid.

[0038] In some specific embodiments of the present invention, in step (4), the base is selected from at least one of sodium hydroxide, potassium hydroxide and sodium bicarbonate.

[0039] In some specific embodiments of the present invention, in step (4), the pH of the product obtained by neutralization is 8-12.

[0040] In some specific embodiments of the present invention, in step (4), the weight ratio of the liquid alkali to the TMQ reaction solution is 0.0001-0.001:1, ensuring that the molar ratio of the added liquid alkali to the residual hydrochloric acid in the TMQ reaction solution is 1.05-1.2:1, and the pH of the solution is adjusted to be alkaline.

[0041] In some specific embodiments of the present invention, based on the total amount of the antioxidant TMQ, the content of the antioxidant TMQ in the antioxidant TMQ is 45-65wt%, wherein the content of the dimer of 2,2,4-trimethyl-1,2-dihydroquinoline is 25-40wt%, and the content of isopropyldiphenylamine is 0-0.5wt%. According to the requirements of the TMQ national standard GB / T8826-2019, the content of the antioxidant TMQ is required to be greater than 40wt%. The antioxidant TMQ obtained by the present invention meets the requirements, and at the same time realizes the recycling of aniline, acetone and hydrochloric acid, and greatly reduces the amount of liquid alkali required for neutralization, thereby realizing a green and environmentally friendly synthesis process.

[0042] In some specific embodiments of the present invention, the softening point of the antioxidant TMQ is 86-97°C.

[0043] The second aspect of the present invention provides a system for preparing an antioxidant TMQ, such as Figure 1As shown, the system includes: a polycondensation reaction device 1 and a separation device 2 connected in sequence; a filtering device 4 and a recovery device 3 connected to the separation device 2, a neutralization device 5 connected to the filtering device 4, and a distillation device 6 connected to the neutralization device 5; wherein the filtering device 4 and the recovery device 3 are also respectively connected to the polycondensation reaction device 1.

[0044] According to the present invention, the polycondensation reaction device 1 is used for polycondensation reaction of aniline and acetone to obtain TMQ polycondensation liquid, and the TMQ polycondensation liquid enters the separation device 2, and the separation device 2 performs component separation to obtain light components and heavy components respectively, wherein the heavy components enter the filtering device 4, and the obtained heavy components are filtered, and the obtained filtrate is the TMQ reaction liquid, which enters the neutralization device 5, is neutralized with liquid alkali to obtain an oil phase, enters the distillation device 6, and is distilled to obtain the antioxidant TMQ, wherein the filter cake obtained by the filtering device 4 is returned to the polycondensation reaction device 1, wherein the light components obtained by the separation device 2 enter the recovery device 3 to recover acetone and aniline, and the recovered acetone and aniline are returned to the polycondensation reaction device 1.

[0045] The present invention will be described in detail below through examples.

[0046] In the following examples and comparative examples, if no specific conditions are specified, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used, if no manufacturer is specified, are all conventional products that can be obtained through commercial channels.

[0047] Example 1

[0048] (1) In a 2000 mL reactor equipped with a thermometer and a condenser, 620 g of aniline and 48.8 g of 30 wt% hydrochloric acid were added, and the mixture was stirred at 110° C. for 3 hours to remove water from the hydrochloric acid. Then, 848 g of acetone was added dropwise at 110° C. for 5 hours to remove water generated by the reaction while reacting. The mixture was maintained for 0.5 h to obtain a TMQ polycondensation reaction liquid.

[0049] (2) The obtained TMQ polycondensation reaction liquid is distilled to obtain light components (acetone 35.4%, water 26.5%, aniline 18.4%, other impurities 19.7%) and heavy components (aniline content is 5.2wt%, and the molar ratio of aniline to the hydrochloric acid catalyst in the heavy components is controlled to be 1.06:1), and the light components are separated and recovered to obtain recovered acetone (normal pressure, collecting the fraction with a gas phase temperature of 0-120° C.) and recovered aniline (100Pa, collecting the fraction with a gas phase temperature of 0-90° C.). Among them, the heavy component contains: 16.4wt% of 2,2,4-trimethyl-1,2-dihydroquinoline and 44.5wt% of TMQ, 5.2wt% of aniline, 0.7wt% of isopropyldiphenylamine, 6.83wt% of aniline hydrochloride, 0.5wt% of isopropyldiphenylamine hydrochloride, 2.5wt% of 2,2,4-trimethyl-1,2-dihydroquinoline pentamer, 1.1wt% of hexamer, and 22.17wt% of other impurities.

[0050] (3) The obtained heavy components were filtered at 120° C. through a filter with a pore size of 1 μm, and the filtrate obtained a TMQ reaction solution (the TMQ reaction solution contained: 17.9 wt% of 2,2,4-trimethyl-1,2-dihydroquinoline, 49.2 wt% of TMQ, 0.1 wt% of aniline, 0.1 wt% of isopropyl diphenylamine, 0.03% of aniline hydrochloride, 0.01 wt% of isopropyl diphenylamine hydrochloride, 2.7 wt% of 2,2,4-trimethyl-1,2-dihydroquinoline pentamer, 1.2 wt% of hexamer, and 28.76 wt% of other impurities). The filter cake obtained a catalyst containing hydrochloric acid of 59.3 g (of which the equivalent hydrogen chloride content was 14.35 g, the molar ratio of aniline to hydrogen chloride was 1.05:1, and the rest was TMQ components), and the obtained filter cake was returned to the polycondensation reaction in step (1).

[0051] (4) The obtained TMQ reaction solution was neutralized with 2 g of 16 wt % sodium hydroxide solution at 90° C. to a pH of 12, and the water was separated and the oil phase was distilled to obtain the antioxidant TMQ.

[0052] According to the national standard method, the content of antioxidant TMQ is 58.34wt%, of which the content of dimer of 2,2,4-trimethyl-1,2-dihydroquinoline is 29.40wt%, the content of isopropyl diphenylamine is 0.2wt%, and the softening point is 89°C, which meets the requirements of TMQ national standard GB / T8826-2019.

[0053] Example 2

[0054] (1) Add 620 g of aniline and 48.8 g of 30 wt% hydrochloric acid to a 2000 mL reactor equipped with a thermometer and a condenser, stir at 110° C. for 3 hours to remove water from the hydrochloric acid, then add 780 g of acetone dropwise over 6 hours at 110° C. while removing water generated by the reaction. After the addition is completed, maintain for 0.5 h to obtain a TMQ polycondensation reaction liquid.

[0055] (2) The obtained TMQ polycondensation reaction liquid was distilled to obtain light components ((acetone 39.5%, water 22.1%, aniline 15.2%, other impurities 23.2%)) and heavy components (aniline content was 5wt%, and the molar ratio of aniline to the hydrochloric acid catalyst in the heavy components was 0.95:1), and the light components were separated and recovered to obtain recovered acetone (normal pressure, collecting the fraction with a gas phase temperature of 0-120°C), recovered aniline (100Pa, collecting the fraction with a gas phase temperature of 0- The heavy component contained: 17.7 wt% of 2,2,4-trimethyl-1,2-dihydroquinoline, 46.3 wt% of TMQ, 5 wt% of aniline, 1.7 wt% of isopropyldiphenylamine, 7.0 wt% of aniline hydrochloride, 1.9 wt% of isopropyldiphenylamine hydrochloride, 3.4 wt% of pentamer of 2,2,4-trimethyl-1,2-dihydroquinoline, 1.6 wt% of hexamer, and 15.4 wt% of other impurities.

[0056] (3) The obtained heavy components were filtered at 120° C. through a filter with a pore size of 1 μm, and the filtrate obtained a TMQ reaction solution (the TMQ reaction solution contained: 19.3 wt% of 2,2,4-trimethyl-1,2-dihydroquinoline, 50.7 wt% of TMQ, 0.02 wt% of aniline, 1.3 wt% of isopropyl diphenylamine, 0.05 wt% of aniline hydrochloride, 0.1 wt% of isopropyl diphenylamine hydrochloride, 3.5 wt% of 2,2,4-trimethyl-1,2-dihydroquinoline pentamer, 1.6 wt% of hexamer, and 23.43 other impurities). The filter cake obtained a catalyst containing hydrochloric acid of 59.5 g (of which the equivalent hydrogen chloride content was 14.25 g, the molar ratio of aniline to hydrogen chloride was 0.95:1, and the rest was TMQ components), and the obtained filter cake was returned to the polycondensation reaction in step (1).

[0057] (4) The obtained TMQ reaction solution was neutralized with 3 g of 16 wt % sodium hydroxide solution at 90° C. to a pH of 12, and water was separated and the oil phase was distilled to obtain the antioxidant TMQ.

[0058] According to the national standard method, the content of antioxidant TMQ is 64.25wt%, of which the content of dimer of 2,2,4-trimethyl-1,2-dihydroquinoline is 31.82wt%, the content of isopropyl diphenylamine is 0.2wt%, and the softening point is 86°C, which meets the requirements of TMQ national standard GB / T8826-2019.

[0059] Example 3

[0060] (1) Add 620 g of aniline and 48.8 g of 30 wt% hydrochloric acid to a 2000 mL reactor equipped with a thermometer and a condenser, stir at 110° C. for 3 hours to remove water from the hydrochloric acid, then add 1000 g of acetone dropwise over 7 hours at 110° C. while removing water generated by the reaction. After the addition is completed, maintain for 0.5 h to obtain a TMQ polycondensation reaction liquid.

[0061] (2) The obtained TMQ polycondensation reaction liquid was distilled to obtain light components ((acetone 54.5%, water 18.2%, aniline 12.1%, other impurities 15.2%)) and heavy components (aniline content was 6.3wt%, and the molar ratio of aniline to the hydrochloric acid catalyst in the heavy components was 1.1:1), and the light components were separated and recovered to obtain recovered acetone (normal pressure, collecting the fraction with a gas phase temperature of 0-100°C), recovered aniline (200Pa, collecting the fraction with a gas phase temperature of 0-8 8°C fraction). Among them, the heavy component contains: 16.6wt% of 2,2,4-trimethyl-1,2-dihydroquinoline, 44.2wt% of TMQ, 6.3wt% of aniline, 1.5wt% of isopropyldiphenylamine, 8.0wt% of aniline hydrochloride, 0.6wt% of isopropyldiphenylamine hydrochloride, 4.1wt% of 2,2,4-trimethyl-1,2-dihydroquinoline pentamer, 1.9wt% of hexamer, and 16.8wt% of other impurities.

[0062] (3) The obtained heavy components were filtered at 120° C. through a filter with a pore size of 3 μm, and the filtrate obtained a TMQ reaction solution (the TMQ reaction solution contained: 18.4 wt% of 2,2,4-trimethyl-1,2-dihydroquinoline and 49.5 wt% of TMQ, 0.5 wt% of aniline, 1.7 wt% of isopropyl diphenylamine, 0.02 wt% of aniline hydrochloride, 0.1 wt% of isopropyl diphenylamine hydrochloride, 2.3 wt% of 2,2,4-trimethyl-1,2-dihydroquinoline pentamer, 1.0 wt% of hexamer, and 26.48 wt% of other impurities). The filter cake obtained 62.2 g of a catalyst containing hydrochloric acid (of which the equivalent hydrogen chloride content was 14.45 g, the molar ratio of aniline to hydrogen chloride was 1.1:1, and the rest was TMQ components), and the obtained filter cake was returned to the polycondensation reaction in step (1).

[0063] (4) The obtained TMQ reaction solution was neutralized with 2 g of 16 wt % sodium hydroxide solution at 90° C. to a pH of 12, and the water was separated and the oil phase was distilled to obtain the antioxidant TMQ.

[0064] According to the national standard method, the content of antioxidant TMQ is 60.73wt%, of which the content of dimer of 2,2,4-trimethyl-1,2-dihydroquinoline is 31.42wt%, the content of isopropyl diphenylamine is 0.1wt%, and the softening point is 97°C, which meets the requirements of TMQ national standard GB / T8826-2019.

[0065] Example 4

[0066] (1) In a 2000 mL reactor equipped with a thermometer and a condenser, 620 g of aniline and 48.8 g of 30 wt% hydrochloric acid were added, and the mixture was stirred at 110° C. for 3 hours to remove water from the hydrochloric acid. Then, 848 g of acetone was added dropwise at 110° C. for 5 hours to remove water generated by the reaction while reacting. The mixture was maintained for 0.5 h to obtain a TMQ polycondensation reaction liquid.

[0067] (2) The obtained TMQ polycondensation reaction liquid is distilled to obtain light components (acetone 45.1%, water 24.5%, aniline 15.4%, other impurities 15%) and heavy components (aniline content is 7.2wt%, and the molar ratio of aniline to the hydrochloric acid catalyst in the heavy components is 2.2:1), and the light components are separated and recovered to obtain recovered acetone (normal pressure, collecting the fraction with a gas phase temperature of 0-80°C) and recovered aniline (200Pa, collecting the fraction with a gas phase temperature of 0-70°C). Among them, the heavy component contains: 16.1wt% of 2,2,4-trimethyl-1,2-dihydroquinoline and 43.7wt% of TMQ, 7.2wt% of aniline, 1.4wt% of isopropyldiphenylamine, 4.6wt% of aniline hydrochloride, 0.5wt% of isopropyldiphenylamine hydrochloride, 3.1wt% of 2,2,4-trimethyl-1,2-dihydroquinoline pentamer, 1.7wt% of hexamer, and 21.7wt% of other impurities.

[0068] (3) The obtained heavy components were filtered at 120° C. through a filter with a pore size of 5 μm, and the filtrate obtained a TMQ reaction solution (the TMQ reaction solution contained: 17.2 wt% of 2,2,4-trimethyl-1,2-dihydroquinoline, 46.6 wt% of TMQ, 3.6 wt% of aniline, 1.1 wt% of isopropyl diphenylamine, 0.5 wt% of aniline hydrochloride, 0.2 wt% of isopropyl diphenylamine hydrochloride, 3.3 wt% of 2,2,4-trimethyl-1,2-dihydroquinoline pentamer, 1.8 wt% of hexamer, and 63.8 wt% of other impurities). The filter cake obtained a catalyst containing hydrochloric acid of 52 g (wherein the equivalent hydrogen chloride content was 12.1 g, the molar ratio of aniline to hydrogen chloride was 1.2:1, and the rest was TMQ components). The obtained filter cake was returned to the polycondensation reaction in step (1), and 2.0 g of hydrochloric acid was added.

[0069] (4) The obtained TMQ reaction solution was neutralized with 4 g of 16 wt % sodium hydroxide solution at 90° C. to a pH of 13, and water was separated and the oil phase was distilled to obtain the antioxidant TMQ.

[0070] According to the national standard method, the content of antioxidant TMQ is 56.63wt%, of which the content of dimer of 2,2,4-trimethyl-1,2-dihydroquinoline is 30.21wt%, the content of isopropyl diphenylamine is 0.1wt%, and the softening point is 92°C, which meets the requirements of TMQ national standard GB / T8826-2019.

[0071] Example 5

[0072] (1) Add 620 g of aniline and 52.5 g of 30 wt% hydrochloric acid to a 2000 ml reactor equipped with a thermometer and a condenser, and stir at 110° C. for 3 hours to remove water from the hydrochloric acid. Then, add 848 g of acetone dropwise over 5 hours at 110° C. while removing water generated by the reaction. The reaction is maintained for 0.5 h to obtain a TMQ polycondensation reaction liquid.

[0073] (2) The obtained TMQ polycondensation reaction liquid is distilled to obtain light components (acetone 51.2%, water 20.3%, aniline 11.3%, other impurities 17.2%) and heavy components (aniline content is 3.4wt%, and the molar ratio of aniline to the hydrochloric acid catalyst in the heavy components is 0.7:1), and the light components are separated and recovered to obtain recovered acetone (normal pressure, collecting the fraction with a gas phase temperature of 0-100°C) and recovered aniline (80Pa, collecting the fraction with a gas phase temperature of 0-80°C). Among them, the heavy component contains: 17.9wt% of 2,2,4-trimethyl-1,2-dihydroquinoline, 42.2wt% of TMQ, 3.4wt% of aniline, 1.6wt% of isopropyldiphenylamine, 4.7wt% of aniline hydrochloride, 1.9wt% of isopropyldiphenylamine hydrochloride, 2.4wt% of 2,2,4-trimethyl-1,2-dihydroquinoline pentamer, 1.1wt% of hexamer, and 24.8wt% of other impurities.

[0074] (3) The obtained heavy components are filtered through a filter with a pore size of 2 μm at 120° C., and the filtrate is used to obtain a TMQ reaction solution (the TMQ reaction solution contains: 19.7 wt% of 2,2,4-trimethyl-1,2-dihydroquinoline, 46.5 wt% of TMQ, 0.1 wt% of aniline, 1.1 wt% of isopropyldiphenylamine, 0.1 wt% of aniline hydrochloride, 0.2 wt% of isopropyldiphenylamine hydrochloride, 2.6 wt% of 2,2,4-trimethyl-1,2-dihydroquinoline pentamer, 1.2 wt% of hexamer, and 28.5 wt% of other impurities). The filter cake obtained was 53.3 g of a catalyst containing hydrochloric acid (of which the equivalent hydrogen chloride content was 13.55 g, the molar ratio of aniline to hydrogen chloride was 0.9:1, and the rest was TMQ components). The obtained filter cake was returned to the polycondensation reaction in step (1), and 2.0 g of hydrochloric acid was added.

[0075] (4) The obtained TMQ reaction solution was neutralized with 8 g of 16 wt % potassium hydroxide solution at 90° C. to a pH of 13, and water was separated and the oil phase was distilled to obtain the antioxidant TMQ.

[0076] According to the national standard method, the content of antioxidant TMQ is 57.31wt%, of which the content of dimer of 2,2,4-trimethyl-1,2-dihydroquinoline is 28.70wt%, the content of isopropyl diphenylamine is 0.1wt%, and the softening point is 91°C, which meets the requirements of TMQ national standard GB / T8826-2019.

[0077] Comparative Example 1

[0078] Add 620g of aniline and 48.8g of 30wt% hydrochloric acid to a 2000mL reactor with a thermometer and a condenser, stir for 3 hours at 120°C to remove water from the hydrochloric acid, then add 848g of acetone dropwise within 5 hours under stirring at 110°C, remove the water generated by the reaction while reacting, and maintain for 0.5h to obtain a TMQ polycondensation reaction liquid. Use 120g of 16wt% sodium hydroxide solution for neutralization at 90°C, the pH value is 11, separate water, and distill the oil phase to obtain TMQ. According to the national standard method, the content of dimer of 2,2,4-trimethyl-1,2-dihydroquinoline is 29.45wt%, the content of TMQ is 57.89wt%, the content of isopropyl diphenylamine is 0.2wt%, and the softening point is 89°C, which meets the requirements of TMQ national standard GB / T8826-2019.

[0079] Through the preparation method of the antioxidant TMQ of the above-mentioned embodiment and comparative example, in embodiments 1-3, the method of the present invention separates the polycondensation liquid and controls the separation conditions of the polycondensation liquid, retains the hydrochloric acid catalyst in the polycondensation system and precipitates it, separates it by filtration, and recovers it, thereby realizing the recycling of the hydrochloric acid catalyst. Compared with the traditional direct neutralization process, the use of alkali in the neutralization process is greatly reduced, and only 2-3g of 16wt% sodium hydroxide is used for neutralization, the liquid alkali required for neutralization is reduced, and the corresponding salt-containing wastewater generated is also greatly reduced. Compared with comparative example 1 (using 8g of 16wt% potassium hydroxide solution for neutralization), 97% can be reduced. % or more of saline wastewater is generated; the molar ratios of aniline and hydrochloric acid in the heavy components after separation of the polycondensation liquid in Examples 4 and 5 are controlled at 2.2:1 and 0.7:1, respectively, and the hydrochloric acid catalyst separation effect is poorer than that in Examples 1-3, and the amount of neutralizing alkali solution is increased, and 4-8g of 16wt% sodium hydroxide is used for neutralization; without separating the light and heavy components of the polycondensation liquid and without controlling the molar ratio of aniline to the hydrochloric acid catalyst in the heavy components (Comparative Example 1), a large amount of alkali is needed to neutralize the hydrochloric acid in the polycondensation reaction process, and 120g of 16wt% sodium hydroxide is used for neutralization, and a large amount of saline wastewater is generated.

[0080] At the same time, the method of the present invention retains the hydrochloric acid catalyst in the polycondensation system and precipitates it through separation of the polycondensation liquid and control of the separation conditions of the polycondensation liquid, and then separates it by filtration and recovers it, thereby realizing the recycling of the hydrochloric acid catalyst. Among them, in Examples 1-3, the hydrogen chloride content in the filter cake reaches 14.25-14.45g, and the content of hydrogen chloride added by adding 48.8g of 30wt% hydrochloric acid is 14.64g, which basically realizes the recycling of 97.3-98.7% of the hydrochloric acid, and Examples 4-5 realize the recycling of 82.7-86% of the hydrochloric acid, while the comparative example does not realize the recycling of the hydrochloric acid. The present invention realizes a green and environmentally friendly synthesis process.

[0081] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing an antioxidant TMQ, characterized in that: The method includes: (1) in the presence of hydrochloric acid catalyst, aniline and acetone are subjected to polycondensation reaction to obtain TMQ polycondensation liquid; (2) separating the obtained TMQ polycondensation liquid to obtain a light component and a heavy component, respectively, while controlling the molar ratio of aniline to the hydrochloric acid catalyst in the heavy component; (3) filtering the obtained heavy components, the obtained filtrate is the TMQ reaction liquid, and the obtained filter cake is returned to the polycondensation reaction in step (1); (4) adding liquid alkali to neutralize the obtained TMQ reaction solution, and distilling the obtained oil phase to obtain the antioxidant TMQ.

2. The preparation method according to claim 1, characterized in that: In step (1), the molar ratio of aniline, acetone and hydrochloric acid catalyst is 1:1.5-10:0.05-0.

5.

3. The preparation method according to claim 1 or 2, characterized in that: In step (1), the polycondensation reaction time is 0.001-10h, and the polycondensation reaction temperature is 90-200°C.

4. The preparation method according to any one of claims 1 to 3, characterized in that: In step (2), the separation is selected from distillation, rectification or fractional distillation.

5. The preparation method according to any one of claims 1 to 4, characterized in that: In step (2), the light component contains 10-40wt% acetone, 10-40wt% water, 5-20wt% aniline and 0-30wt% other impurities; Preferably, the separation and purification of the light component comprises: firstly controlling the separation conditions to be normal pressure and the gas phase temperature to be 0-120°C to separate and recover acetone; then controlling the separation conditions to be normal pressure or reduced pressure to separate and recover aniline, wherein under normal pressure conditions, the gas phase temperature is 121-220°C, and under reduced pressure conditions of 1-200Pa, the gas phase temperature is 0-90°C; Preferably, the light component is separated and refined and then returned to the polycondensation reaction in step (1) as a recycled raw material.

6. The preparation method according to any one of claims 1 to 5, characterized in that: In step (2), the molar ratio of aniline in the heavy component to the hydrochloric acid catalyst is 0.3-2:1, preferably 0.9-1.1:1; Preferably, the heavy component contains 5-20wt% of 2,2,4-trimethyl-1,2-dihydroquinoline, 20-60wt% of TMQ, 0.5-10wt% of aniline, 0.5-2wt% of isopropyldiphenylamine, 1-10wt% of aniline hydrochloride, 0.5-2wt% of isopropyldiphenylamine hydrochloride, 0.5-5wt% of pentamer of 2,2,4-trimethyl-1,2-dihydroquinoline, 0.1-2wt% of hexamer, and 0-30wt% of other impurities; Preferably, the separation and purification of the heavy component includes: the separation condition is normal pressure or reduced pressure; wherein, under normal pressure, the gas phase temperature is 0-220°C, and the heavy component is separated; when the reduced pressure condition is 1-500Pa, the gas phase temperature is 0-90°C, and the heavy component is separated.

7. The preparation method according to any one of claims 1 to 6, characterized in that: In step (3), the filtration temperature is 80-150°C; Preferably, in step (3), the TMQ reaction solution contains: 5-25wt% of 2,2,4-trimethyl-1,2-dihydroquinoline, 20-65wt% of TMQ, 0.01-15wt% of aniline, 0.01-2.5wt% of isopropyldiphenylamine, 0.01-2wt% of aniline hydrochloride, 0-0.5wt% of isopropyldiphenylamine hydrochloride, 0.5-8wt% of 2,2,4-trimethyl-1,2-dihydroquinoline pentamer, 0.1-4wt% of hexamer, and 0-30wt% of other impurities.

8. The preparation method according to any one of claims 1 to 7, characterized in that: In step (4), the liquid alkali is selected from at least one of sodium hydroxide, potassium hydroxide and sodium bicarbonate; Preferably, in step (4), the pH of the product obtained by neutralization is 8-12; Preferably, in step (4), the weight ratio of the liquid alkali to the TMQ reaction solution is 0.0001-0.001:

1.

9. The preparation method according to any one of claims 1 to 8, characterized in that: Based on the total amount of the antioxidant TMQ, the content of TMQ in the antioxidant TMQ is 45-65wt%, wherein the content of the dimer of 2,2,4-trimethyl-1,2-dihydroquinoline is 25-40wt%, and the content of isopropyl diphenylamine is 0-0.5wt%; Preferably, the softening point of the antioxidant TMQ is 86-97°C.

10. A system for preparing an antioxidant TMQ, characterized in that: The system includes: a polycondensation reaction device and a separation device connected in sequence; a filtering device and a recovery device connected to the separation device, a neutralization device connected to the filtering device, and a distillation device connected to the neutralization device; wherein the filtering device and the recovery device are also each connected to the polycondensation reaction device.

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