Method for synthesizing hexadiene by using 3-chloropropene production waste liquid as raw material

Abstract

The invention provides a method for synthesizing hexadiene by using waste liquid for producing 3-chloropropene as a raw material, which comprises the following steps: (1) mixing the waste liquid for producing 3-chloropropene with an entrainer, rectifying in a rectifying tower, condensing gas extracted from the tower top of the rectifying tower to serve as light component waste liquid, condensing gas extracted from a side line to obtain 1, 5-hexadiene, and separating the 1, 5-hexadiene from the light component waste liquid to obtain 1, 5-hexadiene; heavy component waste liquid is extracted from the tower kettle; (2) dissolving 1, 5-hexadiene extracted from the side line of the rectifying tower in the step (1) into a solvent to obtain a reaction solution; in the presence of a catalyst, adding an oxidizing agent into the reaction liquid for reaction to obtain adipic acid; wherein the active component elements of the catalyst are selected from lanthanum element and cobalt element, the mass content of the lanthanum element in the catalyst is 0.5-1%, and the mass content of the cobalt element in the catalyst is 0.2-0.8%. The azeotropic distillation technology is adopted, 1, 5-hexadiene with the purity of 95% or above is obtained from the 3-chloropropene waste liquid through purification, low-cost recovery of 1, 5-hexadiene is achieved, and the discharge amount of three wastes is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of waste resource utilization, and in particular to a method for synthesizing hexadiene by using waste liquid from producing 3-chloropropylene as a raw material. Background Art

[0002] 3-Chloropropene is an important organic synthesis intermediate, commonly used in the production of epichlorohydrin, allyl alcohol, glycerol and other industrial chemicals, and is also a raw material for pesticides, medicines, coatings, etc. At present, the main process route for the production of 3-chloropropene in China is the high-temperature chlorination of propylene. In the separation and purification stage of this process, some waste liquid containing 3-8wt% 3-chloropropene, 1-6wt% 1-chloropropane, 45-73wt% 1,5-hexadiene, 1-8wt% 1-hexene, 1-2wt% 2,2-dichloropropane and other components will be produced.

[0003] Adipic acid, also known as fatty acid, is an important organic dibasic acid, mainly used to produce nylon 66, polyurethane foam and plasticizer. In addition, adipic acid is also widely used in the fields of medicine, spices, pesticides, coatings and dyes. The production technologies commonly used in industry at present include cyclohexane and cyclohexene methods. The cyclohexane method uses cheap benzene as raw material, prepares cyclohexane by hydrogenation, then obtains a mixture of cyclohexanone and cyclohexanol (referred to as KA oil) by air oxidation, and then synthesizes adipic acid by nitric acid oxidation, but this synthesis route will produce a large amount of three wastes, which does not meet the current environmental protection requirements. The cyclohexene method is to prepare cyclohexene by partial hydrogenation of benzene, cyclohexene is hydrated to obtain cyclohexanol, cyclohexanol is then oxidized by nitric acid to prepare adipic acid or cyclohexene is reacted with an oxidant in one step to obtain adipic acid. The process product has good quality and high yield, but it also has the disadvantages of long reaction time, low production efficiency and difficult recovery of catalysts.

[0004] So far, there has been no report on using 3-chloropropylene production waste liquid as raw material to synthesize adipic acid. This method not only reduces the discharge of waste liquid, is more environmentally friendly in terms of process, but also realizes the resource utilization of waste liquid and improves economic benefits. Summary of the invention

[0005] The object of the present invention is to provide a method for synthesizing adipic acid using 3-chloropropene production waste liquid as a raw material, and more specifically, to provide a method for synthesizing adipic acid by catalytically oxidizing 3-chloropropene production waste liquid containing 1,5-hexadiene.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for synthesizing hexadiene by using waste liquid from producing 3-chloropropylene as raw material, comprising the following steps:

[0008] (1) mixing the waste liquid produced from the production of 3-chloropropylene with an azeotropic agent and then distilling the mixture in a distillation tower, wherein the produced gas from the top of the distillation tower is condensed as a light component waste liquid, the produced gas from the side line is condensed to obtain 1,5-hexadiene, and the heavy component waste liquid is produced from the bottom of the tower;

[0009] (2) dissolving the 1,5-hexadiene extracted from the side line of the distillation tower in step (1) in a solvent to obtain a reaction solution; adding an oxidant to the reaction solution in the presence of a catalyst to react and obtain adipic acid;

[0010] The active component elements of the catalyst include lanthanum and cobalt. The mass content of lanthanum in the catalyst is 0.5-1%, and the mass content of cobalt is 0.2-0.8%.

[0011] The waste liquid of 3-chloropropene involved in the present invention includes but is not limited to the bottom of the product refining tower in the process of producing 3-chloropropene by propylene high-temperature chlorination method. In some specific embodiments, the waste liquid of producing 3-chloropropene is composed of: 3-chloropropene content of 3-8wt%, 1-chloropropane content of 1-6wt%, 1,5-hexadiene content of 45-73wt%, 1-hexene content of 1-8wt%, 2,2-dichloropropane content of 1-2wt% and other components.

[0012] In some specific embodiments, the azeotropic agent in step (1) is selected from methanol, ethanol or water; preferably, the feed amount of the azeotropic agent is 8-15wt% of the feed amount of 3-chloropropylene in the waste liquid for producing 3-chloropropylene, for example, 10wt%, 12wt%.

[0013] In the specific implementation method of the present invention, the operating pressure of the distillation tower is atmospheric pressure, the number of plates is 30 to 46, the top reflux ratio is 1:1 to 5:1, and the temperature of the side line produced liquid is controlled at 56 to 58°C.

[0014] In some specific embodiments, in step (2), the catalyst is prepared by the following method:

[0015] Titanium silicon molecular sieve TS-1, inorganic salt containing lanthanum element and inorganic salt containing cobalt element are added to water for impregnation, and then the pH value of the system is adjusted to 2-3, and then aged, filtered, dried and calcined to obtain the catalyst.

[0016] The titanium silicate molecular sieve TS-1 mentioned in the present invention belongs to the Pentasil type heteroatom molecular sieve, an orthorhombic crystal system, and has a three-dimensional pore structure represented by ZSM-5, which is composed of a Z-shaped channel and an elliptical straight channel intersecting therewith.

[0017] In some specific embodiments, the amount of the titanium silicon molecular sieve TS-1 is 5 to 20 wt % of the water mass, preferably 10 to 15;

[0018] Calculated by the amount of lanthanum element, the amount of the inorganic salt containing lanthanum element is 1 to 3 wt% of the titanium silicon molecular sieve TS-1;

[0019] Calculated by the amount of cobalt element, the amount of the inorganic salt containing cobalt element is 0.5-2wt% of the titanium silicon molecular sieve TS-1.

[0020] In some preferred embodiments, the inorganic salt containing the lanthanum element is selected from one or more of lanthanum nitrate hexahydrate, anhydrous lanthanum chloride or hydrated lanthanum acetate; the inorganic salt containing the cobalt element is selected from one or more of cobalt nitrate hexahydrate, cobalt chloride hexahydrate or cobalt acetate tetrahydrate; more preferably, a phosphoric acid aqueous solution, a phosphorous acid aqueous solution or a hypophosphorous acid aqueous solution is used to adjust the pH of the system.

[0021] In some specific preparation processes, the impregnation is carried out at a temperature of 40-65° C. for 1-5 h; the drying is carried out at a temperature of 80-120° C. for 8-20 h; and the calcination is carried out at a temperature of 400-550° C. for 5-10 h.

[0022] In step (2) of the method of the present invention, the specific amount of catalyst used is 2 to 15 wt% of the mass of 1,5-hexadiene, for example, 5 wt%, 8 wt%, 10 wt%, 12 wt%; in some preferred embodiments, the amount of oxidant used is 1 to 2 times the mass of 1,5-hexadiene, for example, 1.2 times, 1.5 times.

[0023] In some specific embodiments, the oxidant is selected from one or more of hydrogen peroxide, nitric acid and peracetic acid; in some preferred embodiments, the oxidant is a mixed aqueous solution of hydrogen peroxide and nitric acid, preferably, the concentration of hydrogen peroxide in the oxidant is 15-30wt%, and the mass of nitric acid is 10-25wt% of the mass of hydrogen peroxide.

[0024] In some specific embodiments, acetone, 2-butanone, and tetrahydrofuran are used as solvents to dissolve 1,5-hexadiene.

[0025] In some specific embodiments, an oxidant is added dropwise to the reaction solution and the reaction temperature is controlled to be 10-35° C. After the addition is completed, the reaction is continued for 1-3 hours. In some preferred embodiments, the time for adding the oxidant is controlled to be completed within 2-5 hours.

[0026] In some specific embodiments, the reaction liquid obtained by the above reaction is filtered to remove the catalyst, the catalyst filter cake can be washed with acetone, and the above reaction liquid and the washing liquid are combined to analyze the yield of adipic acid.

[0027] The above technical solution has the following technical effects:

[0028] The method of the invention adopts azeotropic distillation technology to purify 1,5-hexadiene with a purity of more than 95% from 3-chloropropylene waste liquid, thereby realizing low-cost recovery of 1,5-hexadiene and significantly reducing the discharge of three wastes.

[0029] The method of the present invention adopts a molecular sieve catalyst including lanthanum and cobalt elements, realizes efficient conversion of 1,5-hexadiene in waste liquid into adipic acid, and has the advantages of high reaction yield, mild reaction conditions and easy catalyst recovery. DETAILED DESCRIPTION

[0030] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0031] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0032] Source of raw materials:

[0033] Methanol, molecular sieve TS-1, lanthanum nitrate hexahydrate, cobalt nitrate hexahydrate, phosphoric acid, phosphorous acid, hypophosphorous acid, acetone, hydrogen peroxide solution, nitric acid: all of analytical grade purity, were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0034] The following detection methods are used in the following examples:

[0035] (1) The composition of the waste liquid produced by the production of 3-chloropropene was analyzed by GC-7890 chromatograph. The chromatographic conditions were as follows: initial temperature of 80°C, maintained for 2 min, programmed temperature increase to 150°C at a rate of 10°C / min, maintained for 5 min; vaporization chamber temperature of 200°C, detection chamber temperature of 200°C; FID detection; injection volume of 0.2 μL.

[0036] (2) Adipic acid content: HPLC analysis under the following conditions: chromatographic column: Agilent ZORBAX SB-C18 chromatographic column, 250×4.6 mm; mobile phase: acetic acid buffer solution containing methanol and copper sulfate, wherein the methanol content is 3% by volume, the pH value of the acetic acid buffer solution is 4.5, and the concentration of copper sulfate is 2×10 -4 mol / L; flow rate: 0.5mL / min; detection wavelength: 254nm; temperature: 30℃; injection volume: 50μL.

[0037] Example 1

[0038] The catalyst was prepared as follows:

[0039] 5 g of titanium silicon molecular sieve TS-1 was added to 100 g of water, and then 0.16 g of lanthanum nitrate hexahydrate (calculated as La, 1 wt% of the mass of TS-1) and 0.13 g of cobalt nitrate hexahydrate (calculated as Co, 0.5 wt% of the mass of TS-1) were added, and the mixture was stirred and impregnated at 40 ° C for 5 h, and then 85% phosphoric acid aqueous solution was slowly added to the system until the pH of the system was between 2 and 3, and aged for 2 h; the solid was filtered, dried at 80 ° C for 20 h, and calcined in air atmosphere at a calcination temperature of 400 ° C for 10 h to obtain La 2 O 3 -P-Co 2 O 3 / TS-1(A) molecular sieve catalyst.

[0040] Catalyst La 2 O 3 -P-Co 2 O 3 The mass percentage of the active component lanthanum element in / TS-1(A) is 0.5%, and the mass percentage of the active component cobalt element is 0.2%.

[0041] The waste liquid used in the production of 3-chloropropylene in this embodiment comes from the bottom of the refining tower of the propylene high-temperature chlorination process to produce 3-chloropropylene, and the specific composition is 5wt% of 3-chloropropylene, 6wt% of 1-chloropropane, 73wt% of 1,5-hexadiene, 8wt% of 1-hexene, 1wt% of 2,2-dichloropropane and 7wt% of other components; the following method is used to synthesize hexadiene:

[0042] (1) The above 3-chloropropene waste liquid (feed rate of 10 g / min) and methanol (feed rate of 0.075 g / min, 15 wt% of the feed mass flow rate of 3-chloropropene) were mixed and continuously fed into an azeotropic distillation tower, the distillation tower had 46 theoretical plates, the feed position was the 20th plate (from top to bottom), and the top reflux ratio was 5:1;

[0043] The gas from the top of the tower is produced at a rate of 1.28 g / min, and after condensation, it is used as a light component waste liquid (containing 39.4 wt% of 3-chloropropylene, 46.9 wt% of 1-chloropropane, 7.8 wt% of 1,5-hexadiene, and 5.8 wt% of methanol); the temperature of the gas extracted from the side line is 58°C, and the flow rate is 7.35 g / min. After condensation, refined 1,5-hexadiene (with a purity of 98 wt% and containing 1.9 wt% of 1-hexene) is obtained; a small amount of heavy component waste liquid containing 1,5-hexadiene (45.8 wt% of 1-hexene, 7.0 wt% of 2,2-dichloropropane, and 47.2 wt% of other components) is produced from the bottom of the tower at a flow rate of 1.44 g / min;

[0044] (2) 5 g of 1,5-hexadiene extracted from the side line of the distillation tower in step (1) above was dissolved in 100 g of acetone solvent and 0.75 g of the catalyst La prepared above. 2 O 3 -P-Co 2 O 3 / TS-1(A) were mixed and added into a 250mL reactor, stirring was started, and a 15% hydrogen peroxide / 1.5% nitric acid mixed aqueous solution was slowly added dropwise. The reaction system temperature was controlled to be 10°C using a cooling medium. The addition time was 2h, and the total amount of the mixed aqueous solution added was 34g. After the addition was completed, the reaction was continued for 1h to obtain a reaction solution containing adipic acid.

[0045] The reaction solution was filtered to remove the catalyst, and the catalyst filter cake was washed with 100 g of acetone. After the reaction solution and the washing solution were combined, analysis showed that the mass of the generated adipic acid was 7.9 g, and the yield was 90.5% based on hexadiene.

[0046] Example 2

[0047] The catalyst was prepared as follows:

[0048] 5 g of titanium silicon molecular sieve TS-1 was added to 100 g of water, and then 0.48 g of lanthanum nitrate hexahydrate (3 wt % of the mass of TS-1, in terms of La) and 0.49 g of cobalt nitrate hexahydrate (2 wt % of the mass of TS-1, in terms of Co) were added, and the mixture was stirred and impregnated at 65 ° C for 5 h, and then 85% phosphoric acid aqueous solution was slowly added to the system until the pH of the system was between 2 and 3. After aging for 2 h, the solid was filtered, dried at 120 ° C for 8 h, and calcined in air atmosphere at a calcination temperature of 550 ° C for 5 h to obtain La 2 O 3 -P-Co 2 O 3 / TS-1(B) molecular sieve catalyst.

[0049] Catalyst La 2 O 3 -P-Co 2 O 3 The mass percentage of the active component lanthanum element in / TS-1(B) is 1%, and the mass percentage of the active component cobalt element is 0.8%.

[0050] The composition of the waste liquid for producing 3-chloropropylene and the steps (1) and (2) for synthesizing adipic acid used in this embodiment are the same as those used in the method of Example 1, except that the catalyst used in step (2) of the method of this embodiment is La 2 O 3 -P-Co 2 O 3 / TS-1(B). The reaction solution was filtered to remove the catalyst, and washed with acetone. The reaction solution and the washing solution were combined and analyzed to obtain a yield of 7.6 g of adipic acid based on hexadiene, which was 87.3%.

[0051] Example 3

[0052] The catalyst was prepared as follows:

[0053] 20 g of titanium silicon molecular sieve TS-1 was added to 100 g of water, and then 1.28 g of lanthanum nitrate hexahydrate (2 wt% of the mass of TS-1, in terms of La) and 1.47 g of cobalt nitrate hexahydrate (1.5 wt% of the mass of TS-1, in terms of Co) were added, and stirred and impregnated at 65 ° C for 5 h, and then 85% phosphoric acid aqueous solution was slowly added to the system until the pH of the system was between 2 and 3. After aging for 2 h, the solid was filtered, dried at 100 ° C for 15 h, and placed in an air atmosphere for calcination at a temperature of 450 ° C for 8 h to obtain La 2 O 3 -P-Co 2 O 3 / TS-1(C) molecular sieve catalyst.

[0054] Catalyst La 2 O 3 -P-Co 2 O 3 The mass percentage of the active component lanthanum element in / TS-1(C) is 0.8%, and the mass percentage of the active component cobalt element is 0.4%.

[0055] The composition of the waste liquid for producing 3-chloropropylene and the steps (1) and (2) for synthesizing adipic acid used in this embodiment are the same as those used in the method of Example 1, except that the catalyst used in step (2) of the method of this embodiment is La 2 O 3 -P-Co 2 O 3 / TS-1(C). The reaction solution was filtered to remove the catalyst, and washed with acetone. The reaction solution and the washing solution were combined and analyzed to obtain a yield of 8.1 g of adipic acid based on hexadiene, which was 93.1%.

[0056] Example 4

[0057] The catalyst preparation method used in this example is the same as that in Example 1. The catalyst is La 2 O 3 -P-Co 2 O 3 / TS-1(A).

[0058] The composition of the waste liquid used in the production of 3-chloropropylene in this example is the same as that in Example 1. Hexadiene is synthesized by the following method:

[0059] (1) The above 3-chloropropene waste liquid (feed flow rate of 10 g / min) and methanol (feed flow rate of 0.04 g / min, 8 wt% of the feed mass flow rate of 3-chloropropene) were mixed and continuously fed into an azeotropic distillation tower, the distillation tower had 46 theoretical plates, the feed position was the 20th plate (from top to bottom), and the top reflux ratio was 5:1;

[0060] The gas from the top of the tower is produced at a rate of 1.18 g / min, and after condensation, it is used as a light component waste liquid (containing 41.5 wt% of 3-chloropropylene, 49.1 wt% of 1-chloropropane, 6.0 wt% of 1,5-hexadiene, and 3.3 wt% of methanol); the temperature of the side-line gas is 57.6°C, and the flow rate is 7.46 g / min. After condensation, refined 1,5-hexadiene (with a purity of 96.9 wt%, containing 2.7 wt% of 1-hexene, 0.1% of chloropropylene, and 0.2% of chloropropane) is obtained; a small amount of heavy component waste liquid containing 1,5-hexadiene (42.8 wt% of 1-hexene, 7.2 wt% of 2,2-dichloropropane, and 50 wt% of other components) is produced from the bottom of the tower at a flow rate of 1.40 g / min;

[0061] (2) 5 g of 1,5-hexadiene extracted from the side line of the distillation tower in step (1) above was dissolved in 100 g of acetone solvent and 0.75 g of the catalyst La prepared above. 2 O 3 -P-Co 2 O 3 / TS-1(A) were mixed and added into a 250mL reactor, stirring was started, and a 15% hydrogen peroxide / 1.5% nitric acid mixed aqueous solution was slowly added dropwise. The reaction system temperature was controlled to be 10°C using a cooling medium. The addition time was 2h, and the total amount of the mixed aqueous solution added was 34g. After the addition was completed, the reaction was continued for 1h to obtain a reaction solution containing adipic acid.

[0062] The reaction solution was filtered to remove the catalyst, and the catalyst filter cake was washed with 100 g of acetone. After the reaction solution and the washing solution were combined, analysis showed that the mass of the generated adipic acid was 7.6 g, and the yield was 88.3% based on hexadiene.

[0063] Example 5

[0064] The catalyst preparation method used in this example is consistent with that in Example 1. The catalyst is La 2 O 3 -P-Co 2 O 3 / TS-1(A).

[0065] The composition of the waste liquid used in the production of 3-chloropropylene in this embodiment is the same as that in Example 1; hexadiene is synthesized by the following method:

[0066] (1) The above 3-chloropropene waste liquid (feed rate of 10 g / min) and methanol (feed rate of 0.075 g / min, 15 wt% of the feed mass flow rate of 3-chloropropene) were mixed and continuously fed into an azeotropic distillation tower, the distillation tower had 46 theoretical plates, the feed position was the 20th plate (from top to bottom), and the top reflux ratio was 5:1;

[0067] The gas from the top of the tower is produced at a rate of 1.28 g / min, and after condensation, it is used as a light component waste liquid (containing 39.4 wt% of 3-chloropropylene, 46.9 wt% of 1-chloropropane, 7.8 wt% of 1,5-hexadiene, and 5.8 wt% of methanol); the temperature of the gas extracted from the side line is 58°C, and the flow rate is 7.35 g / min. After condensation, refined 1,5-hexadiene (with a purity of 98 wt% and containing 1.9 wt% of 1-hexene) is obtained; a small amount of heavy component waste liquid containing 1,5-hexadiene (45.8 wt% of 1-hexene, 7.0 wt% of 2,2-dichloropropane, and 47.2 wt% of other components) is produced from the bottom of the tower at a flow rate of 1.44 g / min;

[0068] (2) Take 5 g of the purified 1,5-hexadiene in step (1) and dissolve it in 100 g of acetone solvent and 0.10 g of the catalyst La prepared above. 2 O 3 -P-Co 2 O 3 / TS-1(A) were mixed and added into a 250mL reactor, stirring was started, and a 15% hydrogen peroxide / 1.5% nitric acid mixed aqueous solution was slowly added dropwise. The reaction system temperature was controlled to be 20°C using a cooling medium. The addition time was 5h, and the total amount of the mixed aqueous solution added was 60g. After the addition was completed, the reaction was continued for 3h to obtain a reaction solution containing adipic acid.

[0069] The reaction liquid was filtered to remove the catalyst, and the catalyst filter cake was washed with 100 g of acetone. After the reaction liquid and the washing liquid were combined, analysis showed that the mass of the generated adipic acid was 7.8 g, and the yield was 89.7% based on hexadiene.

[0070] Comparative Example 1

[0071] The catalyst preparation method is the same as that in Example 1, except that cobalt nitrate hexahydrate is not added, and other conditions remain unchanged. The catalyst is denoted as La 2 O 3 / TS-1.

[0072] The waste liquid composition of the production of 3-chloropropylene and the steps (1) and (2) of synthesizing adipic acid used in this embodiment differ from the synthesis conditions of Example 1 only in that the catalyst used in step (2) is the above-mentioned La 2 O 3 / TS-1.

[0073] After the reaction solution was washed with acetone, analysis showed that the mass of the generated adipic acid was 6.2 g, and the yield was 71.3% based on hexadiene.

[0074] Comparative Example 2

[0075] The catalyst preparation method is the same as that in Example 1, and the catalyst is La 2 O 3 -P-Co 2 O 3 / TS-1(A).

[0076] The composition of the waste liquid for producing 3-chloropropylene and the conditions of step (1) for synthesizing adipic acid used in this example are the same as those of step (1) in example 1, and the only difference between step (2) and step (2) in example 1 is that the oxide added is a 15% aqueous hydrogen peroxide solution without nitric acid.

[0077] After the reaction solution was washed with acetone, analysis showed that the mass of the generated adipic acid was 6.9 g, and the yield was 79.3% based on hexadiene.

[0078] Comparative Example 3

[0079] The catalyst preparation method is the same as that in Example 1, except that 1.3 g of cobalt nitrate hexahydrate (in terms of Co, 5 wt% of the mass of TS-1) is added, and other conditions remain unchanged. The catalyst is recorded as La 2 O 3 -P-Co 2 O 3 / TS-1(D).

[0080] Catalyst La 2 O 3 -P-Co 2 O 3 The mass percentage of the active component lanthanum element in / TS-1(D) is 0.5%, and the mass percentage of the active component cobalt element is 1.5%.

[0081] The composition of the waste liquid for producing 3-chloropropylene and the steps (1) and (2) for synthesizing adipic acid used in this example are the same as those in the synthesis method of Example 1, except that the catalyst used in step (2) is the above-mentioned La 2 O 3 -P-Co 2 O 3 / TS-1(D).

[0082] After the reaction solution was washed with acetone, analysis showed that the mass of the generated adipic acid was 6.5 g, and the yield was 74.6% based on hexadiene.

Claims

1. A method for synthesizing hexadiene using waste liquid from the production of 3-chloropropylene as raw material, characterized in that: The following steps are involved: (1) mixing the waste liquid produced from the production of 3-chloropropylene with an azeotropic agent and then distilling the mixture in a distillation tower, wherein the produced gas from the top of the distillation tower is condensed as a light component waste liquid, the produced gas from the side line is condensed to obtain 1,5-hexadiene, and the heavy component waste liquid is produced from the bottom of the tower; (2) dissolving the 1,5-hexadiene extracted from the side line of the distillation tower in step (1) in a solvent to obtain a reaction solution; adding an oxidant to the reaction solution in the presence of a catalyst to react and obtain adipic acid; The active component elements of the catalyst include lanthanum and cobalt. The mass content of lanthanum in the catalyst is 0.5-1%, and the mass content of cobalt is 0.2-0.8%.

2. The method according to claim 1, characterized in that In step (1), the waste liquid produced by producing 3-chloropropene comprises: 3-chloropropene 3-8wt%, 1-chloropropane 1-6wt%, 1,5-hexadiene 45-73wt%, 1-hexene 1-8wt%, 2,2-dichloropropane 1-2wt% and other components.

3. The method according to claim 1 or 2, characterized in that: The azeotropic agent in step (1) is selected from methanol, ethanol or water; Preferably, the feed amount of the azeotropic agent is 8-15 wt% of the feed amount of 3-chloropropene in the waste liquid for producing 3-chloropropene.

4. The method according to any one of claims 1 to 3, characterized in that The operating pressure of the distillation tower is atmospheric pressure, the number of plates is 30 to 46, the top reflux ratio is 1:1 to 5:1, and the temperature of the side line produced liquid is controlled at 56 to 58°C.

5. The method according to any one of claims 1 to 4, characterized in that: The catalyst in step (2) is prepared by the following method: Titanium silicon molecular sieve TS-1, inorganic salt containing lanthanum element and inorganic salt containing cobalt element are added to water for impregnation, and then the pH value of the system is adjusted to 2-3, and then aged, filtered, dried and calcined to obtain the catalyst.

6. The method according to claim 5, characterized in that The amount of the titanium silicon molecular sieve TS-1 is 5 to 20 wt% of the mass of water; Calculated by the amount of lanthanum element, the amount of the inorganic salt containing lanthanum element is 1 to 3 wt% of the titanium silicon molecular sieve TS-1; Calculated by the amount of cobalt element, the amount of the inorganic salt containing cobalt element is 0.5-2wt% of the titanium silicon molecular sieve TS-1; Preferably, the inorganic salt containing lanthanum is selected from one or more of lanthanum nitrate hexahydrate, anhydrous lanthanum chloride or hydrated lanthanum acetate; the inorganic salt containing cobalt is selected from one or more of cobalt nitrate hexahydrate, cobalt chloride hexahydrate or cobalt acetate tetrahydrate; More preferably, the pH of the system is adjusted using an aqueous phosphoric acid solution, an aqueous phosphorous acid solution, or an aqueous hypophosphorous acid solution.

7. The method according to claim 6, characterized in that The immersion is carried out at a temperature of 40 to 65° C. for 1 to 5 hours; The drying is carried out at a temperature of 80 to 120° C. for 8 to 20 hours; The calcination is carried out at a temperature of 400 to 550° C. for 5 to 10 hours.

8. The method according to any one of claims 1 to 7, characterized in that: In step (2), the amount of the catalyst used is 2 to 15 wt% of the mass of 1,5-hexadiene; Preferably, the amount of the oxidant used is 1 to 2 times the mass of 1,5-hexadiene.

9. The method according to claim 8, characterized in that The oxidant is selected from one or more of hydrogen peroxide, nitric acid and peracetic acid; Preferably, the oxidant is a mixed aqueous solution of hydrogen peroxide and nitric acid; Preferably, the concentration of hydrogen peroxide in the oxidant is 15-30wt%, and the mass of nitric acid is 10-25wt% of the mass of hydrogen peroxide; Preferably, the solvent is selected from one or more of acetone, 2-butanone and tetrahydrofuran.

10. The method according to any one of claims 1 to 9, characterized in that: Add an oxidant dropwise to the reaction solution and control the reaction temperature to be 10 to 35° C., and continue the reaction for 1 to 3 hours after the addition is completed; Preferably, the time for adding the oxidant dropwise is controlled to be completed within 2 to 5 hours.