Resource utilization method of industrial aniline waste liquid

Abstract

The invention discloses a preparation method of a catalyst and a method for preparing cyclohexylamine and dicyclohexylamine through resource utilization of industrial aniline waste liquid by using the catalyst. The catalyst carrier is diatomite and / or CaCO3, the active component is Ni, and the auxiliary agent is selected from one or more of zirconium, copper, cobalt, zinc, manganese and rhenium. The prepared catalyst is high in activity and stable in performance, industrial aniline waste liquid can be subjected to resource utilization to generate cyclohexylamine and dicyclohexylamine, reaction conditions are mild, operation is easy, and the catalyst is safe, environmentally friendly and suitable for industrial large-scale production.

Description

Technical Field

[0001] The invention relates to a method for resource utilization of chemical waste liquid, and more specifically to a method for resource utilization of industrial aniline waste liquid to prepare cyclohexylamine and dicyclohexylamine. Background Art

[0002] Aniline is the simplest primary aromatic amine, a colorless oily liquid with a strong amine smell and high toxicity. It is an important chemical intermediate and is widely used in the production of rubber additives, dyes, medicines, pesticides and other products. There are three main synthesis processes: phenol amination method, nitrobenzene iron powder reduction method and nitrobenzene catalytic hydrogenation method.

[0003] Cyclohexylamine is an important organic fine chemical intermediate, widely used in rubber additives, food additives, antiseptic, papermaking, plastic processing and textile industries. There are four main synthesis processes: aniline catalytic hydrogenation, nitrocyclohexane reduction, cyclohexanol catalytic ammonolysis and cyclohexanone catalytic ammonolysis. The industrial production method is aniline hydrogenation reduction and cyclohexanone / cyclohexanol catalytic amination.

[0004] Dicyclohexylamine is mainly used as rubber accelerator, printing and dyeing auxiliaries, corrosion inhibitor and rust preventer, and material auxiliaries. In addition, as an antioxidant additive for fuel oil, dicyclohexylamine can not only change the combustion performance of fuel oil, but also prevent fuel oil from corroding equipment. There are four main synthesis processes: diphenylamine hydrogenation method, cyclohexanone cyclohexylamine method, cyclohexylamine catalytic hydrogenation method, and aniline hydrogenation method.

[0005] In the production process of MDI, there is a condensation reaction, that is, aniline reacts with formaldehyde to form DAM. In the entire condensation process, since aniline is excessive, it needs to be recycled in the system. After a long period of circulation, cyclohexylamine, cyclohexanol and other impurities will be produced. When the content of cyclohexylamine and cyclohexanol is high, the mutual solubility of aniline and water will increase, and the interface in the phase separator will be inseparable, which will seriously affect the stable operation of the device. Therefore, the condensation process needs to regularly discharge waste liquid containing high concentrations of cyclohexylamine and cyclohexanol. Due to the large volume of MDI, the amount of this waste liquid generated each year is very large. At present, this waste liquid is sent to the torch for incineration. After incineration, nitrogen oxides will be produced, forming acid rain and polluting the environment. At present, there is no literature reporting the resource utilization method of this waste liquid.

[0006] In summary, it is necessary to develop a method for resource utilization of industrial aniline waste liquid to achieve waste utilization and reduce harm to the environment. Summary of the invention

[0007] In view of the above technical problems, the present invention provides a method for resource utilization of industrial aniline waste liquid, and the waste liquid can be used to prepare cyclohexylamine and dicyclohexylamine.

[0008] In order to achieve the above invention object, the present invention adopts the following technical solutions:

[0009] One aspect of the present invention provides a hydrogenation catalyst for resource utilization of industrial aniline waste liquid, and the technical scheme adopted is as follows:

[0010] A catalyst for resource utilization of industrial aniline waste liquid, the catalyst comprising a carrier, an active component and an auxiliary agent;

[0011] Wherein, the carrier is diatomaceous earth and / or CaCO3, the active component is Ni, and the auxiliary agent is selected from one or more of zirconium, copper, cobalt, zinc, manganese, and rhenium, preferably cobalt and / or zirconium;

[0012] In the present invention, in a specific embodiment, the content of the active component Ni is 40-65wt%, preferably 50-60wt%; the content of the auxiliary agent is 0.05-2.5wt% (for example, 0.1%, 0.2%, 0.5%, 1%, 1.5%, 2%, etc.), preferably 0.1-1wt%, based on the total mass of the catalyst.

[0013] Another aspect of the present invention provides a method for preparing the catalyst.

[0014] A method for preparing the catalyst, comprising the following steps:

[0015] S1: impregnating the support with an aqueous solution of a metal salt corresponding to the nickel salt and the additive, drying and calcining to obtain a catalyst precursor;

[0016] S2: shaping the catalyst precursor to obtain a catalyst with a regular shape.

[0017] In the present invention, the nickel salt or metal salt in S1 is selected from corresponding soluble salts, preferably nitrates;

[0018] The drying temperature is 80-120° C., preferably 100-110° C.; the drying time is 4-12 hours, preferably 6-8 hours; the roasting temperature is 300-600° C., preferably 400-500° C., and the time is 6-12 hours, preferably 8-10 hours.

[0019] In the present invention, the shaping described in S2 can be cylindrical, clover-shaped, spherical, honeycomb-shaped, or strip-shaped, preferably cylindrical.

[0020] Another object of the present invention is to provide a method for preparing cyclohexylamine and dicyclohexylamine by resource utilization of industrial aniline waste liquid, and the technical scheme adopted is as follows:

[0021] A method for resource utilization of industrial aniline waste liquid, comprising:

[0022] SS1: dehydrating industrial aniline waste liquid A to obtain industrial aniline waste liquid B;

[0023] SS2: Industrial aniline waste liquid B is mixed with aniline, and a certain amount of alcohol auxiliary agent is added, and a hydrogenation reaction is carried out under the action of hydrogen and a catalyst to obtain cyclohexylamine and dicyclohexylamine.

[0024] In the present invention, the industrial aniline waste liquid A described in SS1 refers to the waste liquid generated in the MDI condensation reaction process, and a typical composition thereof is: aniline (10-40wt%), cyclohexylamine (20-40wt%), cyclohexanol (5-15wt%), water (20-40wt%), chlorobenzene (0.05-1wt%), biphenyl (0.05-1wt%), diphenylamine (0.05-1wt%), cyclohexylaniline (0.05-1wt%), N-paraphenylaminoaniline (0.05-1wt%), etc.

[0025] In the present invention, the dehydration described in SS1 can be carried out by extraction, distillation and the like, as long as the water content in the waste liquid A is removed to ≤ 0.5 wt % to avoid affecting the reaction.

[0026] In the present invention, the industrial aniline waste liquid B described in SS2 is blended with aniline, wherein the mass fraction of the industrial aniline waste liquid B is 1-10wt%, preferably 2-5wt%, of the total mass of the industrial aniline waste liquid B plus the blended aniline.

[0027] In the present invention, the alcohol auxiliary agent described in SS2 is methanol and / or ethanol, preferably methanol, and the amount of the alcohol auxiliary agent is 0.5-5wt% of the total mass of industrial aniline waste liquid B plus formulated aniline, preferably 2-3wt%.

[0028] In the present invention, the catalyst needs to be activated before the hydrogenation reaction of SS2, and conventional activation methods in the art can be used.

[0029] In the present invention, the reaction temperature of the hydrogenation reaction of SS2 is 150-210°C, preferably 160-190°C; the reaction pressure is 50-400KPaG, preferably 100-300KPaG; the molar ratio of hydrogen to amine (all amines) is 8-20:1, preferably 10-15:1; the mass space velocity of the raw material (excluding hydrogen) is 0.05-0.4g / g(cat) / h, preferably 0.1-0.3g / g(cat) / h.

[0030] In the present invention, the reaction between the raw materials and impurities is as follows:

[0031]

[0032]

[0033] The beneficial effects of the present invention are:

[0034] (1) The catalyst used in the present invention can effectively decompose chlorobenzene in a hydrogen environment by introducing an auxiliary agent, thereby preventing chlorobenzene from deactivating the catalyst. Ammonia generated by the reaction system can react with hydrogen chloride to generate ammonium chloride, which is dissolved in water generated by the reaction system and carried out of the reactor; in addition, the synergy between the active component Ni and the auxiliary agent can decompose the heavy components in the waste liquid to generate cyclohexylamine, benzene, cyclohexane and other substances, thereby avoiding poisoning the catalyst and extending the life of the catalyst.

[0035] (2) The present invention adds a small amount of alcohol substances to the raw materials, which can be hydrogenolyzed to generate alkanes and water under the catalyst system of the present invention. Huge heat is generated during the hydrogenolysis process, which can stimulate the rapid hydrogenolysis of chlorobenzene and other amine heavy components. In addition, the water generated by the reaction can wash ammonium chloride and the tar of the reaction itself, thereby realizing the online regeneration of the catalyst.

[0036] (3) The catalyst prepared by the present invention can recycle industrial aniline waste liquid into cyclohexylamine and dicyclohexylamine. The reaction conditions are mild, the operation is simple, and the catalyst is safe and environmentally friendly, which is suitable for large-scale industrial production. DETAILED DESCRIPTION

[0037] The present invention is further described by the following embodiments, but the present invention is not limited to the listed embodiments.

[0038] The conditions for gas chromatography analysis in the following examples are: Agilent DB-5 chromatographic column, injection port temperature 280°C, FID detector temperature 300°C, column flow rate 1.5 ml / min, hydrogen flow rate 40 ml / min, air flow rate 400 ml / min, and programmed temperature rise mode of 60°C for 5 min, heating to 280°C at 15°C / min, and holding for 5 min.

[0039] Unless otherwise specified, the raw materials used in the following examples or comparative examples are all Aladdin reagent grade raw materials. Some of the raw materials are described as follows:

[0040] Aniline waste liquid: industrial grade, Wanhua Chemical

[0041] Aniline: Industrial grade, Wanhua Chemical

[0042] The main equipment information is as follows:

[0043] Fixed bed reactor: The manufacturer is Beijing Tuochuan;

[0044] Horizontal flow pump: The manufacturer is Beijing Satellite.

[0045] Example 1

[0046] 1# Catalyst precursor preparation:

[0047] Use 300 ml of deionized water to prepare an impregnation solution containing 50 g of nickel, 1 g of zirconium, and 0.2 g of cobalt nitrate, and add 48.8 g of diatomaceous earth by impregnation. After impregnation for 24 hours, dry at 110°C for 6 hours, calcine at 500°C for 8 hours, and then press into tablets to obtain a cylindrical 1# catalyst precursor.

[0048] Pretreatment of industrial aniline waste liquid A:

[0049] Take 200g of industrial aniline waste liquid A (composed of 25wt% aniline + 35wt% cyclohexylamine + 5wt% cyclohexanol + 32wt% water + 0.5wt% chlorobenzene + 0.3wt% biphenyl + 0.7wt% diphenylamine + 0.5wt% cyclohexylaniline + 0.5wt% N-paraphenylaminoaniline + 0.5wt% other unknown substances), extract with 400g benzene in two equal batches, combine the extracts after extraction and perform vacuum distillation to remove benzene to obtain waste liquid B with a water content of 0.2wt%.

[0050] Hydrogenation reaction:

[0051] 50 g of 1# catalyst precursor was loaded in the middle of a fixed bed reactor and activated under pure hydrogen conditions at 400° C. for 48 h. After activation, the temperature was cooled to room temperature to obtain 1# catalyst.

[0052] Industrial aniline waste liquid B and aniline are mixed to obtain a 2wt% industrial aniline waste liquid B solution (i.e., the mass fraction of industrial aniline waste liquid B is 2wt% of the total mass of industrial aniline waste liquid B plus mixed aniline), and then methanol accounting for 2wt% of the total mass of industrial aniline waste liquid B plus mixed aniline is added. The reaction temperature is 180°C, the reaction pressure is 200KPaG, the molar ratio of hydrogen to amine is 12:1, the mass space velocity of the raw materials is 0.2g / g(cat) / h, and after 24h of reaction, sampling is performed for analysis, and the conversion rate of aniline is 100%, the content of cyclohexylamine in the mother liquor is 28.6%, the content of dicyclohexylamine is 70.9%, the content of cyclohexanol is 0.05%, and the rest is other impurities. After 500h of operation, sampling is performed for analysis, and the conversion rate of aniline is 100%, and the catalyst activity is stable.

[0053] Example 2

[0054] Preparation of 2# catalyst precursor:

[0055] Use 300 ml of deionized water to prepare an impregnation solution containing 40 g of nickel, 2 g of cobalt, and 0.05 g of zinc nitrate, and add 57.95 g of diatomaceous earth by impregnation. After impregnation for 24 hours, dry at 120°C for 4 hours, and calcine at 600°C for 6 hours to form a clover-shaped 2# catalyst precursor.

[0056] Pretreatment of industrial aniline waste liquid A:

[0057] Take 200g of industrial aniline waste liquid A (composed of 10wt% aniline + 40wt% cyclohexylamine + 8wt% cyclohexanol + 39wt% water + 0.05wt% chlorobenzene + 0.8wt% biphenyl + 0.05wt% diphenylamine + 0.8wt% cyclohexylaniline + 1.0wt% N-paraaniline aniline + 0.3wt% other unknown substances), use atmospheric distillation to remove water therein, and obtain waste liquid B with a water content of 0.40%.

[0058] Hydrogenation reaction:

[0059] 50 g of 2# catalyst precursor was loaded in the middle of the fixed bed reactor and activated under pure hydrogen conditions at 350° C. for 48 h. After the activation, the temperature was cooled to room temperature to obtain 2# catalyst.

[0060] Industrial aniline waste liquid B and aniline are mixed to obtain a 1wt% industrial aniline waste liquid B solution, and then 3wt% of ethanol is added, which accounts for the total mass of the industrial aniline waste liquid B and the mixed aniline. The reaction temperature is 160°C, the reaction pressure is 300KPaG, the molar ratio of hydrogen to amine is 8:1, the mass space velocity of the raw materials is 0.3g / g(cat) / h, and after 24h of reaction, sampling is performed for analysis, and the conversion rate of aniline is 100%, the content of cyclohexylamine in the mother liquor is 33.85%, the content of dicyclohexylamine is 65.74%, the content of cyclohexanol is 0.08%, and the rest is other impurities. After 500h of operation, sampling is performed for analysis, and the conversion rate of aniline is 100%, and the catalyst activity is stable.

[0061] Example 3

[0062] 3# Catalyst precursor preparation:

[0063] Use 300 ml of deionized water to prepare an impregnation solution containing 60 g of nickel, 0.5 g of zirconium, and 0.1 g of manganese nitrate. Add 39.4 g of diatomaceous earth by impregnation. After impregnation for 24 hours, dry at 100°C for 8 hours, calcine at 400°C for 10 hours, and shape to obtain a strip-shaped 3# catalyst precursor.

[0064] Pretreatment of industrial aniline waste liquid A:

[0065] Take 200g of industrial aniline waste liquid A (composed of 28wt% aniline + 30wt% cyclohexylamine + 10wt% cyclohexanol + 28wt% water + 1wt% chlorobenzene + 0.5wt% biphenyl + 0.5wt% diphenylamine + 1wt% cyclohexylaniline + 0.2wt% N-para-anilinoaniline + 0.8wt% other unknown substances), extract it with 400g cyclohexane in two equal batches, combine the extracts after extraction and perform vacuum distillation to remove cyclohexane to obtain waste liquid B with a water content of 0.30%.

[0066] Hydrogenation reaction:

[0067] 50 g of 3# catalyst precursor was loaded in the middle of the fixed bed reactor and activated under pure hydrogen conditions at 400° C. for 48 h. After the activation, the temperature was cooled to room temperature to obtain 3# catalyst.

[0068] Industrial aniline waste liquid B is mixed with aniline to obtain a 5wt% industrial aniline waste liquid B solution, and then 5wt% of methanol is added, which accounts for the total mass of the industrial aniline waste liquid B plus the mixed aniline. The reaction temperature is 190°C, the reaction pressure is 400KPaG, the molar ratio of hydrogen to amine is 15:1, the mass space velocity of the raw materials is 0.1g / g(cat) / h, and after 24h of reaction, sampling is performed for analysis, and the conversion rate of aniline is 100%, the content of cyclohexylamine in the mother liquor is 27.05%, the content of dicyclohexylamine is 72.50%, the content of cyclohexanol is 0.13%, and the rest is other impurities. After 500h of operation, sampling is performed for analysis, and the conversion rate of aniline is 100%, and the catalyst activity is stable.

[0069] Comparative Example 1 (Industrial aniline waste liquid A is not dehydrated, compared with Example 1)

[0070] Hydrogenation reaction:

[0071] 50 g of the 1# catalyst precursor in Example 1 was loaded in the middle of a fixed bed reactor and activated under pure hydrogen conditions at 400° C. for 48 h. After the activation, the temperature was cooled to room temperature to obtain 1# catalyst.

[0072] The same industrial aniline waste liquid A as in Example 1 was directly mixed with aniline to obtain a 2wt% industrial aniline waste liquid A solution, and then 2wt% of methanol was added, accounting for the total mass of the industrial aniline waste liquid A plus the mixed aniline. The reaction temperature was 180°C, the reaction pressure was 200KPaG, the molar ratio of hydrogen to amine was 12:1, the mass space velocity of the raw materials was 0.2g / g(cat) / h, and the sample was taken for analysis after 24h of reaction. The conversion rate of aniline was 100%, the content of cyclohexylamine in the mother liquor was 30.4%, the content of dicyclohexylamine was 68.3%, the content of cyclohexanol was 0.12%, and the rest was other impurities. After running for 200h, the sample was taken for analysis. The conversion rate of aniline was 98.5%, and the catalyst activity decreased.

[0073] Comparative Example 2 (without adding alcohol additives, compared with Example 1)

[0074] Hydrogenation reaction:

[0075] The catalyst precursor was prepared according to the method of Example 1. 50g of the catalyst precursor was loaded in the middle of the fixed bed reactor, activated under 400℃ pure hydrogen conditions for 48h, and cooled to room temperature after the activation to obtain a catalyst. The same industrial waste aniline B as in Example 1 was used to mix industrial aniline waste liquid B with aniline to obtain a 2wt% industrial aniline waste liquid B solution. The reaction temperature was 180℃, the reaction pressure was 200KPaG, the molar ratio of hydrogen to amine was 12:1, the mass space velocity of the raw material was 0.2g / g(cat) / h, and the sample was taken for analysis after 24h of reaction. The conversion rate of aniline was 99.5%, the content of cyclohexylamine in the mother liquor was 30.3%, the content of dicyclohexylamine was 67.3%, the content of cyclohexanol was 0.08%, and the rest was other impurities. After running for 100h, the sample was taken for analysis. The conversion rate of aniline was 97.3%, and the catalyst activity decreased.

Claims

1. A hydrogenation catalyst, comprising a carrier, an active component and an additive; in, The carrier is diatomaceous earth and / or CaCO3, the active component is Ni, and the auxiliary agent is selected from one or more of zirconium, copper, cobalt, zinc, manganese, and rhenium, preferably cobalt and / or zirconium; Preferably, the content of the active component Ni is 40-65wt%, preferably 50-60wt%; the content of the auxiliary agent is 0.05-2.5wt%, preferably 0.1-1wt%, based on the total mass of the catalyst.

2. A method for preparing the catalyst according to claim 1, comprising the following steps: S1: impregnating the support with an aqueous solution of a metal salt corresponding to the nickel salt and the additive, drying and calcining to obtain a catalyst precursor; S2: shaping the catalyst precursor to obtain the catalyst.

3. The method according to claim 2, wherein: In S1, the drying temperature is 80-120°C, the drying time is 4-12h, and the roasting temperature is 300-600°C, and the time is 6-12h.

4. A method for resource utilization of industrial aniline waste liquid, comprising: SS1: dehydrating industrial aniline waste liquid A to obtain industrial aniline waste liquid B; SS2: Industrial aniline waste liquid B is mixed with aniline, and a certain amount of alcohol auxiliary agent is added, and a hydrogenation reaction is carried out under the action of hydrogen and the catalyst described in claim 1 to obtain cyclohexylamine and dicyclohexylamine.

5. The method according to claim 4, wherein: The industrial aniline waste liquid A comprises: 10-40wt% of aniline, 20-40wt% of cyclohexylamine, 5-15wt% of cyclohexanol, 20-40wt% of water, 0.05-1wt% of chlorobenzene, 0.05-1wt% of biphenyl, 0.05-1wt% of diphenylamine, 0.05-1wt% of cyclohexylaniline and 0.05-1wt% of N-paraphenylaminoaniline.

6. The method according to claim 4 or 5, wherein: The dehydration described in SS1 removes the water in the waste liquid A to a content of ≤0.5wt%.

7. The method according to any one of claims 4 to 6, wherein: The industrial aniline waste liquid B described in SS2 is mixed with aniline, wherein the mass fraction of the industrial aniline waste liquid B is 1-10wt%, preferably 2-5wt%, of the total mass of the industrial aniline waste liquid B plus the mixed aniline.

8. The method according to any one of claims 4 to 7, wherein: The alcohol auxiliary agent described in SS2 is methanol and / or ethanol, preferably methanol.

9. The method according to claim 8, wherein: The amount of the alcohol auxiliary agent used is 0.5-5wt% of the total mass of the industrial aniline waste liquid B plus the prepared aniline, preferably 2-3wt%.

10. The method according to any one of claims 4 to 9, wherein: The reaction temperature of the hydrogenation reaction of SS2 is 150-210°C, the reaction pressure is 50-400KPaG, the molar ratio of hydrogen to amine is 8-20:1, and the mass space velocity of the raw material is 0.05-0.4g / g(cat) / h.

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