Treatment method for toluene purification and application thereof

Abstract

The invention discloses a toluene purification treatment method and application thereof, and the toluene purification treatment method comprises the following steps: carrying out catalytic conversion on toluene in an acidic environment at 60 DEG C or below by adopting a porous material metal catalyst, mixing the converted liquid with alkali liquor, and separating to obtain purified toluene. According to the treatment method, non-aromatic hydrocarbon and C8 / C9 aromatic hydrocarbon substances in toluene are converted into micromolecular substances or acidic substances, the micromolecular substances or acidic substances are removed in an alkaline water washing mode, when toluene is used for nitration reaction, the content of fatty acid and benzoic acid substances in the nitration reaction process is reduced, and the yield of the nitration reaction is improved. Non-aromatic hydrocarbon and C8 / C9 aromatic hydrocarbon substances are prevented from being converted into carboxylic acid emulsified impurities in the nitration reaction process, and the emulsification risk of the nitration reaction is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of toluene purification, and in particular to a toluene purification processing method and application thereof. Background Art

[0002] Toluene is the main raw material for the production of dinitrotoluene (DNT), which is widely used in explosives, polyurethane foaming raw materials and other organic synthetic intermediates; in industrial production, petroleum cracking products are one of the important sources of toluene. Toluene refining is separated by distillation tower refining, but it is extremely difficult to completely remove non-aromatic and C8 / C9 aromatic impurities with similar boiling points to toluene.

[0003] The non-aromatic hydrocarbons in toluene are mainly dimethylcyclohexane, n-octane, methylheptadiene, dimethylcyclohexene, ethylcyclohexene and ethylcyclohexane. C8 / C9 aromatic hydrocarbons are mainly ethylbenzene, xylene and trimethylbenzene. In the nitration reaction, non-aromatic hydrocarbons are easily oxidized to form fatty acids under acidic conditions. Due to the influence of multiple methyl groups in C8 / C9 aromatic hydrocarbons, they are more active than toluene and are easily oxidized to form methylbenzoic acid compounds. Fatty acids and methylbenzoic acid impurities contain hydrophilic and lipophilic groups. When toluene containing non-aromatic hydrocarbons and C8 / C9 aromatic hydrocarbons is used as a raw material, it is easy for the water-oil two phases to form an emulsion in the nitration reaction, and the phases cannot be separated to enter the next process, forcing the device to be shut down for treatment, causing huge economic losses.

[0004] Therefore, it is necessary to remove non-aromatic impurities with boiling points close to toluene and C8 / C9 aromatic impurities. In the currently disclosed prior art, the methods that can achieve the removal of non-aromatic compounds with boiling points close to toluene are usually membrane unit separation methods (see patent application document CN 114206813 A) and physical adsorption methods (see patent application document CN 1403426A). Among them, the membrane unit separation method has high requirements for the membrane unit and high separation cost; the physical adsorption method is limited to the removal of alkaline high-content non-aromatic hydrocarbons and C8 / C9 aromatic substances, and the removal effect of other substances is not ideal. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is how to efficiently remove low-content non-aromatic hydrocarbons and C8 / C9 aromatic hydrocarbons from toluene, reduce the risk of emulsification in the nitration reaction, and provide a solution to the above problem.

[0006] A method for purifying toluene, comprising:

[0007] A porous metal catalyst is used in toluene to carry out catalytic conversion in an acidic environment below 60°C, and the converted liquid is then mixed with an alkaline solution to separate and obtain purified toluene.

[0008] The porous material metal catalyst is a porous material loaded with a metal active component, wherein the mass proportion of the metal active component in the porous material is 1-30%, preferably 5-15%, for example, the mass proportion of the metal active component in the porous material is 1%, 2%, 5%, 10%, 15%, 20%, 25%, 30%, etc.;

[0009] And / or, the average particle size of the catalyst is 4 to 16 μm, preferably 8 to 16 μm, for example, the average particle size is 4 μm, 7 μm, 9 μm, 11 μm, 13 μm, 16 μm, etc.;

[0010] And / or, the specific surface area of ​​the catalyst is 500 to 800 m 2 / g, for example: the specific surface area is 500m 2 / g, 550m 2 / g, 600m 2 / g, 650m 2 / g、700m 2 / g, 750m 2 / g、800m 2 / g, etc.

[0011] The metal active component includes one or more of tantalum, chromium, aluminum, zirconium and molybdenum; typical but non-limiting combinations of the metal active components include a combination of tantalum, chromium and aluminum, a combination of tantalum, zirconium and molybdenum, a combination of zirconium, aluminum and molybdenum, and a combination of tantalum, chromium, aluminum, zirconium and molybdenum.

[0012] Preferably, among the metal elements of the catalyst, the tantalum content is 0.5-10%, preferably 3-5%, for example, the tantalum content is 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc.; the chromium content is 0-5%, preferably 0.5-2%, for example, the chromium content is 0.5%, 1%, 1.5%, 2%, etc.; the aluminum content is 0-5%, preferably 1-2%, for example, the aluminum content is 0. 5%, 1%, 2%, 3%, 4%, 5%, etc.; zirconium content 0.5-10%, preferably 1-2.5%, for example: zirconium content 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc.; molybdenum content 0.5-10%, preferably 4-6.5%, for example: molybdenum content 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc. When calculating the percentage composition, the percentage of active ingredients refers to the mass of the metal element represented by the active component in the compound containing the active component. For example, if tantalum element exists in the form of tantalum silicate, the percentage of tantalum is only calculated based on the mass of "tantalum element" therein.

[0013] More preferably, the tantalum element is selected from any one or a combination of more than one of sodium tantalate, ammonium tantalate, tantalum oxalate, tantalum fluoride or tantalum iodide; the chromium element is selected from any one or a combination of more than one of chromium nitrate, chromium sulfate, chromium chloride, potassium chromate, sodium chromate or ammonium chromate; the aluminum element is selected from any one or a combination of more than one of aluminum chloride, aluminum sulfate or aluminum nitrate; the zirconium element is selected from any one or a combination of more than one of zirconium nitrate, zirconium sulfate, ammonium zirconium basic carbonate or zirconium oxychloride; the molybdenum element is selected from any one or a combination of more than one of molybdenum nitrate, potassium molybdate, sodium molybdate or ammonium molybdate.

[0014] And / or, the porous material includes one or more of diatomaceous earth, zeolite, porous alumina and porous silica.

[0015] Preferably, the average particle size of the porous material is 3 to 16 μm; and / or the specific surface area of ​​the porous material is 500 to 800 m 2 / g.

[0016] The preparation process of the porous material metal catalyst is as follows: using porous materials to perform surface modification of polymers and metal ions to obtain a catalyst precursor, and sintering and activating the catalyst precursor to obtain the porous material metal catalyst.

[0017] The surface modification process is as follows: a polymer raw material, a metal ion raw material, and a porous material are mixed to obtain a mixed solution, ammonia water is added dropwise to the mixed solution to adjust the pH to 8 to 11, agitating the mixture for polymerization, separating the solid and the liquid, washing with deionized water until neutral, and drying to obtain a catalyst precursor;

[0018] And / or, the sintering activation process is: treating at 350-450° C. for 2-3 hours in an inert gas environment;

[0019] and / or, the mass ratio of the effective substance in the raw material of the polymer to the porous material is 1:(1-50);

[0020] And / or, the more raw materials of metal ions, the more metal ions theoretically loaded in the porous material, the better its performance, but based on the comprehensive consideration of cost and performance, the mass ratio of the raw materials of metal ions to the porous material in the present invention is preferably 1: (0.5-7); for example, 1: 0.5, 1: 1, 1: 2, 1: 3, 1: 4, 1: 5, 1: 6, 1: 7, etc.;

[0021] And / or, the raw material of the polymer includes at least one of methylcyclohexanol, methylcyclohexylamine, methylaniline, diaminotoluene, and dopamine hydrochloride; the raw material of the polymer is preferably TDA hydrogenated wastewater and dopamine hydrochloride; the TDA hydrogenated wastewater in the present invention generally includes any one or more combinations of methylcyclohexanol, methylcyclohexylamine, methylaniline, and diaminotoluene with a total content of less than 5%.

[0022] The dopamine hydrochloride undergoes a self-polymerization reaction under weak alkaline conditions. During the reaction, the surface of the porous material is modified by the polymer, and metal ions are loaded in the porous material.

[0023] The inert gas includes any one or more of nitrogen, helium, argon or carbon dioxide;

[0024] And / or, the temperature of the stirring polymerization is 20 to 35° C., and the time of the stirring polymerization is 4 to 12 hours.

[0025] The catalytic conversion process is as follows: toluene, a porous material metal catalyst and a dilute acid are mixed to obtain a mixed system, stirred for reaction, and separated into layers to obtain primary toluene;

[0026] And / or, the mixed separation process is: mixing the primary toluene with the alkali solution, stirring and washing, and standing and separating the layers to obtain the purified toluene.

[0027] In the mixed system, the amount of catalyst added is 0.5-5% of the mass of toluene, preferably 2.5-5%, for example: the amount of catalyst added is 0.5%, 1%, 2%, 3%, 4%, 5% etc. of the mass of toluene; and / or, the mass concentration of the dilute acid is 0.5-10wt%, and the mass of acid in the dilute acid is 1%-15% of the mass of toluene;

[0028] And / or, the dilute acid is any one or more of dilute nitric acid, dilute sulfuric acid, and dilute nitrous acid;

[0029] and / or, the stirring reaction temperature is 30 to 60° C., preferably 40 to 50° C.;

[0030] And / or, the stirring reaction time is 3 to 15 minutes, preferably 5 to 10 minutes.

[0031] The alkali solution is one or more of ammonia water, sodium hydroxide solution, and potassium hydroxide solution;

[0032] And / or, the pH value during the stirring washing is 7.5 to 11, preferably 8 to 9;

[0033] And / or, the temperature during the stirring washing is 30 to 60° C., preferably 40 to 50° C.;

[0034] And / or, the stirring washing time is 3 to 15 minutes, preferably 5 to 10 minutes.

[0035] The purified toluene obtained by the above treatment method is used as a raw material in a nitration reaction.

[0036] The technical solution of the present invention has the following advantages:

[0037] 1. The method provided by the present invention adopts a porous material to prepare a catalyst, mixes toluene and the obtained catalyst in an acidic environment to obtain a mixed system, filters solid particles from the mixed system to obtain primary toluene; and washes the primary toluene with alkali to obtain purified toluene. The treatment method of the present invention converts non-aromatic hydrocarbons and C8 / C9 aromatic hydrocarbons in toluene into small molecules such as carbon dioxide and water or acidic substances such as fatty acids and benzoic acid, and removes them by washing with alkaline water to obtain purified toluene; when the purified toluene is used for nitration reaction, the content of fatty acids and benzoic acid substances in the nitration reaction is reduced, and the conversion of non-aromatic hydrocarbons and C8 / C9 aromatic hydrocarbons into carboxylic acid emulsified impurities during the nitration reaction is avoided, thereby reducing the emulsification risk of the nitration reaction.

[0038] 2. The present invention realizes the purification of raw material toluene and ensures that the raw material toluene is almost not lost during the processing process through temperature control. DETAILED DESCRIPTION

[0039] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0040] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0041] In the following examples, toluene comes from the raw material of the DNT section of the TDI production device of Wanhua Chemical Group Co., Ltd., and the total amount of non-aromatic hydrocarbons and C8 / C9 aromatic hydrocarbon compounds in toluene is 302 ppm.

[0042] TDA hydrogenation wastewater comes from the TDA section of the TDI production unit of Wanhua Chemical Group Co., Ltd., including 0.02% methylcyclohexanol, 0.01% methylcyclohexylamine, 0.01% methylaniline, and 0.01% diaminotoluene.

[0043] Example 1

[0044] Weigh 5.3g sodium tantalate, 2.1g chromium nitrate, and 4.5g aluminum nitrate and dissolve them in 100g deionized water and stir to fully dissolve the metal salts, add 30g porous silicon oxide, and then add 5g dopamine hydrochloride and 100g TDA hydrogenated wastewater, slowly drip 15wt% ammonia water into the mixture to adjust the pH to 9, and stir and polymerize at 25°C for 6h. Separate the solid and liquid, wash with deionized water to neutrality, and obtain a catalyst precursor after drying. The catalyst precursor was calcined at 400°C and nitrogen atmosphere for 2.5h, and catalyst A was obtained after cooling to room temperature. The catalyst parameters were measured by laser particle size distribution analyzer Bettersize2600, specific surface pore size analyzer Minix, and X-ray fluorescence analyzer ARL-OPTIMX, where the X-ray tube power of X-ray fluorescence analysis was 400w and the test environment was helium atmosphere; after testing, the average particle size of the catalyst was 10μm and the specific surface area was 760m 2 / g, tantalum content is 9.2%, chromium content is 0.89%, and aluminum content is 1.1%.

[0045] In a 1L fully mixed kettle reactor, add 200g toluene, 200g 5% nitric acid solution and 8g catalyst A prepared according to the above steps, and control the stirring speed to 1100rpm at 40°C. After reacting for 10min, stand in a stratifier for 5min to obtain primary toluene. Return the primary toluene to the reactor, add 100mL ammonia water for washing, control the pH to 9, the temperature to 40°C, and the stirring washing time to 7min. Stand to obtain the purified toluene a.

[0046] After sampling and testing, the total content of non-aromatic hydrocarbons and C8 / C9 aromatic hydrocarbons in toluene a was 35ppm.

[0047] Example 2

[0048] Weigh 5.3g sodium tantalate, 1.5g zirconium nitrate, and 1.2g molybdenum nitrate and dissolve them in 100g deionized water and stir to fully dissolve the metal salts, add 30g zeolite, and then add 6g dopamine hydrochloride and 100g TDA hydrogenated wastewater, slowly add 15wt% ammonia water to the mixture to adjust the pH to 8.5, and stir and polymerize at 25°C for 6h. Separate the solid and liquid, wash with deionized water to neutrality, and obtain a catalyst precursor after drying. Calcine the catalyst precursor at 350°C and argon atmosphere for 3h, and obtain catalyst B after cooling to room temperature. After testing, the average particle size of the catalyst is 12μm and the specific surface area is 630m 2 / g, the tantalum content is 8.4%, the zirconium content is 0.88%, and the molybdenum content is 1.4%.

[0049] In a 1L fully mixed tank reactor, add 200g toluene, 200g of a mixed solution of 1.0% nitric acid and 0.5% nitrous acid, and 10g of the catalyst B prepared according to the above steps, and control the stirring speed to 1100rpm at 45°C. After reacting for 10 minutes, stand in a stratifier for 5 minutes to obtain primary toluene. Return the primary toluene to the reactor, add 100mL of ammonia water for washing, control the pH to 9, the temperature to 45°C, and the stirring washing time to 7 minutes. Stand to obtain the purified toluene b.

[0050] After sampling and testing, the total content of non-aromatic hydrocarbons and C8 / C9 aromatic hydrocarbons in toluene b was 22ppm.

[0051] Example 3

[0052] Weigh 5.3g of sodium tantalate, 4.2g of aluminum nitrate, and 3.2g of molybdenum nitrate and dissolve them in 100g of deionized water and stir to fully dissolve the metal salts. Add 30g of porous silicon oxide, and then add 7g of dopamine hydrochloride and 100g of TDA hydrogenated wastewater. Slowly add 15wt% ammonia water to the mixture to adjust the pH to 9, and stir and polymerize at 25°C for 12h. Separate the solid and liquid, wash with deionized water until neutral, and obtain a catalyst precursor after drying. Calcine the catalyst precursor at 450°C in a nitrogen and carbon dioxide atmosphere for 2h, and obtain catalyst C after cooling to room temperature. After testing, the average particle size of the catalyst is 16μm and the specific surface area is 510m 2 / g, the tantalum content is 8.9%, the aluminum content is 1.1%, and the molybdenum content is 5.7%.

[0053] In a 1L fully mixed tank reactor, add 200g toluene, 200g 5% sulfuric acid solution and 8g catalyst C prepared according to the above steps, and control the stirring speed to 1100rpm at 50°C. After reacting for 8 minutes, stand in a stratifier for 5 minutes to obtain primary toluene. Return the primary toluene to the reactor, add 100mL ammonia water for washing, control the pH to 8.5, the temperature to 50°C, and the stirring washing time to 7 minutes. Stand to obtain the purified toluene c.

[0054] After sampling and testing, the total content of non-aromatic hydrocarbons and C8 / C9 aromatic hydrocarbons in toluene c was 46ppm.

[0055] Example 4

[0056] Weigh 4.5g sodium tantalate and 3.1g molybdenum nitrate and dissolve them in 100g deionized water and stir to fully dissolve the metal salt, add 30g diatomaceous earth, then add 6g dopamine hydrochloride and 100g TDA hydrogenated wastewater, slowly drip 15wt% ammonia water into the mixture to adjust the pH to 8.5, and stir and polymerize at 25°C for 6h. Separate the solid and liquid, wash with deionized water to neutrality, and dry to obtain a catalyst precursor. The catalyst precursor was calcined at 400°C in a helium atmosphere for 2.5h, and then cooled to room temperature to obtain catalyst D. After testing, the average particle size of the catalyst was 14μm, the specific surface area was 630m2 / g, the tantalum content was 7.6%, and the molybdenum element was 5.7%.

[0057] In a 1L fully mixed tank reactor, add 200g toluene, 200g 7% nitric acid solution and 6g catalyst D prepared according to the above steps, and control the stirring speed to 1100rpm at 35°C. After reacting for 10min, stand in a stratifier for 5min to obtain primary toluene. Return the primary toluene to the reactor, add 100mL sodium hydroxide solution for washing, control the pH to 9, the temperature to 40°C, and the stirring washing time to 7min. Stand to obtain the purified toluene d.

[0058] After sampling and testing, the total content of non-aromatic hydrocarbons and C8 / C9 aromatic hydrocarbons in toluene d was 38ppm.

[0059] Example 5

[0060] Weigh 0.4g sodium tantalate and 4.2g chromium nitrate and dissolve them in 100g deionized water and stir to fully dissolve the metal salt, add 30g porous alumina, then add 6g dopamine hydrochloride and 100g TDA hydrogenated wastewater, slowly add 15wt% ammonia water to the mixture to adjust the pH to 10, and stir and polymerize at 35°C for 4h. Separate the solid and liquid, wash with deionized water to neutrality, and obtain a catalyst precursor after drying. Calcine the catalyst precursor at 400°C and nitrogen atmosphere for 2.5h, and obtain catalyst E after cooling to room temperature. After testing, the average particle size of the catalyst is 4μm and the specific surface area is 560m 2 / g, tantalum content is 0.5% and chromium content is 2%.

[0061] In a 1L fully mixed tank reactor, add 200g toluene, 200g 15% nitric acid solution and 5g catalyst E prepared according to the above steps, and control the stirring speed to 1100rpm at 60°C. After reacting for 3min, stand in a stratifier for 5min to obtain primary toluene. Return the primary toluene to the reactor, add 100mL ammonia water for washing, control the pH to 11, the temperature to 60°C, and the stirring washing time to 15min. Stand to obtain the purified toluene e.

[0062] After sampling and testing, the total content of non-aromatic hydrocarbons and C8 / C9 aromatic hydrocarbons in toluene e was 77ppm.

[0063] Example 6

[0064] Weigh 3.2g of sodium tantalate, 10g of chromium nitrate, 18g of aluminum nitrate, 7.5g of zirconium nitrate, and 5g of molybdenum nitrate and dissolve them in 200g of deionized water and stir to fully dissolve the metal salts. Add 30g of porous silicon oxide, and then add 12g of dopamine hydrochloride and 100g of TDA hydrogenated wastewater. Slowly add 15wt% ammonia water to the mixture to adjust the pH to 11, and stir and polymerize at 20°C for 6h. Separate the solid and liquid, wash with deionized water until neutral, and obtain a catalyst precursor after drying. Calcine the catalyst precursor at 400°C and nitrogen atmosphere for 2.5h, and obtain catalyst F after cooling to room temperature. After testing, the average particle size of the catalyst is 8μm and the specific surface area is 640m 2 / g, tantalum content is 5%, chromium content is 5%, aluminum content is 5%, zirconium content is 5%, and molybdenum content is 10%.

[0065] In a 1L fully mixed tank reactor, add 200g toluene, 200g 5% nitric acid solution and 5g catalyst F prepared according to the above steps, and control the stirring speed to 1100rpm at 30°C. After reacting for 15min, stand in a stratifier for 5min to obtain primary toluene. Return the primary toluene to the reactor, add 100mL ammonia water for washing, control the pH to 7.5, the temperature to 30°C, and the stirring washing time to 3min. Stand to obtain the purified toluene f.

[0066] After sampling and testing, the total content of non-aromatic hydrocarbons and C8 / C9 aromatic hydrocarbons in toluene f was 20ppm.

[0067] Example 7

[0068] The difference between this embodiment and embodiment 1 is that the raw material of the polymer used in the catalyst precursor is only dopamine hydrochloride, that is, TDA hydrogenation wastewater is replaced by water, and the rest is the same as embodiment 1. After testing, the average particle size of the catalyst is 10 μm, and the specific surface area is 730 m 2 / g, the tantalum content is 9.0%, the chromium content is 0.82%, and the aluminum content is 0.99%.

[0069] After purification, toluene g was sampled and tested, and the total content of non-aromatic hydrocarbons and C8 / C9 aromatic hydrocarbons was 39ppm.

[0070] Example 8

[0071] The difference between this embodiment and embodiment 2 is that the amount of dopamine hydrochloride added as the raw material of the polymer used in the catalyst precursor is 0.6 g, and the rest is the same as embodiment 2. After testing, the average particle size of the catalyst is 10 μm, and the specific surface area is 520 m 2 / g, the tantalum content is 4.4%, the zirconium content is 0.48%, and the molybdenum content is 0.81%.

[0072] After purification, toluene was sampled and tested, and the total content of non-aromatic hydrocarbons and C8 / C9 aromatic hydrocarbons was 66ppm.

[0073] Example 9

[0074] The difference between this embodiment and embodiment 4 is that the amount of catalyst D added to the 1L fully mixed tank reactor is 1g, and the rest is the same as embodiment 4.

[0075] After purification, toluene i was sampled and tested, and the total content of non-aromatic hydrocarbons and C8 / C9 aromatic hydrocarbons was 57ppm.

[0076] Comparative Example 1

[0077] The difference from Example 1 is that 200 g toluene and 200 g 5% nitric acid solution were added to a 1 L fully mixed tank reactor, but the prepared catalyst A was not added, and the stirring speed was controlled at 1100 rpm at 40° C. The purified toluene j was allowed to stand.

[0078] After sampling and testing, the total content of non-aromatic hydrocarbons and C8 / C9 aromatic hydrocarbons in toluene j was 289 ppm.

[0079] Comparative Example 2

[0080] The difference from Example 1 is that no supported metal salt is added during the preparation of the catalyst, thereby obtaining catalyst H. The purified toluene k is allowed to stand.

[0081] The preparation process of catalyst H is as follows: add 30g of the same porous silicon oxide as in Example 1 to 100g of deionized water, then add 5g of dopamine hydrochloride and 100g of TDA hydrogenated wastewater, slowly drip 15wt% ammonia water into the mixture to adjust the pH to 9, and stir and polymerize at 25°C for 6h. Separate the solid and liquid, wash with deionized water to neutrality, and dry to obtain a catalyst precursor. The catalyst precursor was calcined at 400°C in a nitrogen atmosphere for 2.5h, and then cooled to room temperature to obtain catalyst H. After testing, the average particle size of catalyst H is 11μm and the specific surface area is 780m 2 / g.

[0082] After sampling and testing, the total content of non-aromatic hydrocarbons and C8 / C9 aromatic hydrocarbons in toluene k was 284 ppm.

[0083] Test example:

[0084] 15 g of concentrated nitric acid, 5 g of water and 60 g of concentrated sulfuric acid were weighed and mixed to form a nitration mixed acid. 14 g of toluene purified in the embodiment and the comparative example was mixed with 36 g of the nitration mixed acid. After stirring and reacting at 55° C. for 10 min, the mixture was allowed to stand and separate. The separation time is shown in Table 1 below.

[0085] Table 1

[0086] Layering time Example 1 41s Example 2 34s Example 3 48s Example 4 43s Example 5 79s Example 6 33s Example 7 46s Example 8 78s Example 9 65s Comparative Example 1 ＞180s Comparative Example 2 ＞180s

[0087] Obviously, the above embodiments are only examples for clear explanation, and are not intended to limit the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from them are still within the protection scope of the invention.

Claims

1. A method for purifying toluene, characterized in that: include: A porous metal catalyst is used in toluene to carry out catalytic conversion in an acidic environment below 60°C, and the converted liquid is then mixed with an alkaline solution to separate and obtain purified toluene.

2. The processing method according to claim 1, characterized in that: The porous material metal catalyst is a porous material loaded with metal active components, and the mass proportion of the metal active components in the porous material is 1 to 30%, preferably 5 to 15%; and / or, the average particle size of the catalyst is 4 to 16 μm, preferably 8 to 16 μm; And / or, the specific surface area of ​​the catalyst is 500 to 800 m 2 / g.

3. The processing method according to claim 2, characterized in that: The metal active component includes one or more of tantalum, chromium, aluminum, zirconium and molybdenum; And / or, the porous material includes one or more of diatomaceous earth, zeolite, porous alumina and porous silica.

4. The processing method according to any one of claims 1 to 3, characterized in that: The preparation process of the porous material metal catalyst is as follows: using porous material to perform surface modification of polymer and metal ions to obtain a catalyst precursor, and sintering and activating the catalyst precursor to obtain the porous material metal catalyst.

5. The processing method according to claim 4, characterized in that: The surface modification process is as follows: a polymer raw material, a metal ion raw material, and a porous material are mixed to obtain a mixed solution, ammonia water is added dropwise to the mixed solution to adjust the pH to 8 to 11, agitating the mixture for polymerization, separating the solid and the liquid, washing with deionized water until neutral, and drying to obtain a catalyst precursor; And / or, the sintering activation process is: treating at 350-450° C. for 2-3 hours in an inert gas environment; and / or, the mass ratio of the effective substance in the raw material of the polymer to the porous material is 1:(1-50); and / or, the mass ratio of the raw material of the metal ions to the porous material is 1:(0.5-7); And / or, the raw material of the polymer includes at least one of methylcyclohexanol, methylcyclohexylamine, methylaniline, diaminotoluene and dopamine hydrochloride.

6. The processing method according to claim 5, characterized in that: The inert gas includes any one or more of nitrogen, helium, argon or carbon dioxide; And / or, the temperature of the stirring polymerization is 20 to 35° C., and the time of the stirring polymerization is 4 to 12 hours.

7. The processing method according to any one of claims 1 to 6, characterized in that: The catalytic conversion process is as follows: toluene, a porous material metal catalyst and a dilute acid are mixed to obtain a mixed system, stirred for reaction, and separated into layers to obtain primary toluene; And / or, the mixed separation process is: mixing the primary toluene with the alkali solution, stirring and washing, and standing and separating the layers to obtain the purified toluene.

8. The processing method according to claim 7, characterized in that: In the mixed system, the amount of catalyst added is 0.5-5% of the mass of toluene, preferably 2.5-5%; And / or, the mass concentration of the dilute acid is 0.5-10wt%, and the mass of the acid in the dilute acid is 1%-15% of the mass of toluene; And / or, the dilute acid is any one or more of dilute nitric acid, dilute sulfuric acid, and dilute nitrous acid; and / or, the stirring reaction temperature is 30 to 60° C., preferably 40 to 50° C.; And / or, the stirring reaction time is 3 to 15 minutes, preferably 5 to 10 minutes.

9. The processing method according to claim 7, characterized in that: The alkali solution is one or more of ammonia water, sodium hydroxide solution, and potassium hydroxide solution; And / or, the pH value during the stirring washing is 7.5 to 11, preferably 8 to 9; And / or, the temperature during the stirring washing is 30 to 60° C., preferably 40 to 50° C.; And / or, the stirring washing time is 3 to 15 minutes, preferably 5 to 10 minutes.

10. Use of the purified toluene obtained by the treatment method according to any one of claims 1 to 9 as a raw material in a nitration reaction.