Method for producing 1, 6-naphthalene disulfonic acid by using 1-naphthalene sulfonic acid reaction filtrate

Abstract

The invention relates to a method for producing 1, 6-naphthalene disulfonic acid by using 1-naphthalene sulfonic acid reaction filtrate, and belongs to the technical field of compound preparation. The method for producing the 1, 6-naphthalene disulfonic acid by using the 1-naphthalene sulfonic acid reaction filtrate comprises the following steps: (1) heating the 1-naphthalene sulfonic acid reaction filtrate, and concentrating under reduced pressure to obtain a concentrated solution with the acidity of 88-92%; and (2) removing vacuum, adding naphthalene and concentrated sulfuric acid into the concentrated solution obtained in the step (1), carrying out heat preservation reaction at 130-150 DEG C for 3-5 hours, cooling and crystallizing to obtain the 1, 6-naphthalene disulfonic acid. According to the preparation method, the 1-naphthalene sulfonic acid reaction filtrate is fully utilized, energy conservation and emission reduction are effectively achieved, the production cost is saved, and the prepared 1, 6-naphthalene disulfonic acid product is high in purity and meets the market requirement.

Description

Technical Field

[0001] The invention belongs to the technical field of compound preparation, and particularly relates to a method for producing 1,6-naphthalene disulfonic acid by utilizing 1-naphthalenesulfonic acid reaction filtrate. Background Art

[0002] 1,6-Naphthalenedisulfonic acid and its sodium salt are widely used in dyes, organic synthesis and other fields. Due to its special chemical properties, it is often used as a dye intermediate, especially in the synthesis of certain specific types of dyes. In addition, it can also be used as a synthetic raw material for other chemical products, such as surfactants and detergents. In the agricultural field, 1,6-naphthalenedisulfonic acid and its derivatives are also used as one of the ingredients of pesticides. The current common preparation method of 1,6-naphthalenedisulfonic acid is to synthesize 1,6-naphthalenedisulfonic acid through the sulfonation reaction of naphthalene and concentrated sulfuric acid, and then convert it into a sodium salt form to obtain sodium 1,6-naphthalenedisulfonate, but its cost is relatively high, which is not conducive to energy conservation and environmental protection.

[0003] At present, the preparation process of 1-naphthalenesulfonic acid mostly uses naphthalene as raw material and concentrated sulfuric acid as sulfonating agent, reacts under certain temperature conditions, and then obtains 1-naphthalenesulfonic acid through purification, crystallization and filtration. The filtrate obtained after the reaction contains a large amount of useful chemical substances. At present, the filtrate is generally treated as waste liquid, which is neither energy-saving nor environmentally friendly, and does not meet the concept of green chemistry.

[0004] Therefore, how to comprehensively utilize the 1-naphthalenesulfonic acid reaction filtrate is an urgent problem to be solved. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems existing in the above-mentioned prior art and provide a method for producing 1,6-naphthalene disulfonic acid by utilizing 1-naphthalenesulfonic acid reaction filtrate.

[0006] The present invention is achieved through the following technical solutions:

[0007] The present invention provides a method for producing 1,6-naphthalene disulfonic acid by utilizing 1-naphthalenesulfonic acid reaction filtrate, comprising the following steps:

[0008] (1) heating the 1-naphthalenesulfonic acid reaction filtrate, and concentrating under reduced pressure to obtain a concentrated solution with an acidity of 88%-92%;

[0009] (2) removing the vacuum, adding naphthalene and concentrated sulfuric acid to the concentrated solution obtained in step (1), keeping the temperature at 130° C.-150° C. for 3 h-5 h, cooling, and crystallizing to obtain the 1,6-naphthalenedisulfonic acid.

[0010] The present invention uses the filtrate after the reaction of preparing 1-naphthalenesulfonic acid as a raw material, concentrates under reduced pressure to obtain a concentrated solution, then adds naphthalene and concentrated sulfuric acid, and controls the reaction conditions to convert sulfonated products such as 1-naphthalenesulfonic acid in the concentrated solution into 1,6-naphthalenedisulfonic acid. The preparation method of the present invention uses the reaction filtrate as a raw material, can fully realize the recycling of chemical substances in the reaction filtrate, thereby reducing the discharge of waste, conforming to the principles of green chemistry and sustainable development, and can reduce production costs, save energy and protect the environment.

[0011] As a preferred embodiment of the method for producing 1,6-naphthalene disulfonic acid using 1-naphthalenesulfonic acid reaction filtrate of the present invention, in the step (1), the 1-naphthalenesulfonic acid reaction filtrate comprises the following components in mass percentage: 40%-50% water, 10%-14% 1-naphthalenesulfonic acid, 4%-6% 2-naphthalenesulfonic acid, 1.5%-3% 1,6-naphthalene disulfonic acid, and 30%-40% sulfuric acid; more preferably, the 1-naphthalenesulfonic acid reaction filtrate comprises the following components in mass percentage: 47% water, 12% 1-naphthalenesulfonic acid, 4.9% 2-naphthalenesulfonic acid, 2.1% 1,6-naphthalene disulfonic acid, and about 36% sulfuric acid.

[0012] The raw material used in the present invention is the filtrate after the product crystallization filtration when naphthalene reacts with concentrated sulfuric acid to prepare 1-naphthalenesulfonic acid, which contains a small amount of 1-naphthalenesulfonic acid and reaction by-products. The present invention uses the reaction filtrate as a raw material and develops a specific method to prepare high-purity 1,6-naphthalenedisulfonic acid, which can effectively save energy and reduce emissions and conform to the concept of sustainable development. In addition, the present invention finds that the reaction filtrate of the above components can prepare 1,6-naphthalenedisulfonic acid with higher purity and higher conversion rate.

[0013] As a preferred embodiment of the method for producing 1,6-naphthalene disulfonic acid using 1-naphthalenesulfonic acid reaction filtrate of the present invention, in the step (1), the heating temperature is 120°C-140°C.

[0014] As a preferred embodiment of the method for producing 1,6-naphthalene disulfonic acid using 1-naphthalenesulfonic acid reaction filtrate of the present invention, in the step (1), the pressure during the reduced pressure concentration is -0.07Mpa to -0.095Mpa.

[0015] As a preferred embodiment of the method for producing 1,6-naphthalene disulfonic acid using 1-naphthalenesulfonic acid reaction filtrate of the present invention, in the step (1), the acidity of the concentrated solution is 90%.

[0016] The present invention has found that the acidity of the concentrated solution will also affect the reaction. The concentrated solution with an acidity of 88%-92% can improve the purity and selectivity of 1,6-naphthalene disulfonic acid, and the concentrated solution with an acidity of 90% has the best effect.

[0017] As a preferred embodiment of the method for producing 1,6-naphthalene disulfonic acid using 1-naphthalenesulfonic acid reaction filtrate of the present invention, in the step (2), the mass percentage concentration of the concentrated sulfuric acid is 98%.

[0018] As a preferred embodiment of the method for producing 1,6-naphthalene disulfonic acid using 1-naphthalenesulfonic acid reaction filtrate of the present invention, in the step (2), the molar ratio of naphthalene to sulfuric acid is 1:(3-5), and the sulfuric acid includes the sulfuric acid in the concentrated solution and the concentrated sulfuric acid in the step (2). Preferably, the molar ratio of naphthalene to sulfuric acid is 1:(3.5-4.5).

[0019] The ratio of naphthalene to sulfuric acid will affect the selectivity of preparing 1,6-naphthalenedisulfonic acid. When the molar ratio of naphthalene to sulfuric acid is the above ratio, 1,6-naphthalenedisulfonic acid has a higher selectivity.

[0020] As a preferred embodiment of the method for producing 1,6-naphthalene disulfonic acid using 1-naphthalenesulfonic acid reaction filtrate of the present invention, in the step (2), the temperature of the insulation reaction is 140° C. and the time is 4 hours.

[0021] The reaction temperature and reaction time will also affect the reaction results. When the temperature of the insulation reaction is 130°C-150°C and the time is 3h-5h, 1,6-naphthalene disulfonic acid has higher selectivity and purity, and the more preferred temperature is 140°C and 4h.

[0022] As a preferred embodiment of the method for producing 1,6-naphthalene disulfonic acid using 1-naphthalenesulfonic acid reaction filtrate of the present invention, in the step (2), the temperature is cooled to 10°C-30°C.

[0023] Preferably, in the step (2), water is added to control the acidity of the liquid after the reaction to crystallize 1,6-naphthalene disulfonic acid.

[0024] The present invention also provides a method for producing sodium 1,6-naphthalene disulfonate by utilizing the 1-naphthalenesulfonic acid reaction filtrate, comprising the following steps:

[0025] (1) heating the 1-naphthalenesulfonic acid reaction filtrate, and concentrating under reduced pressure to obtain a concentrated solution with an acidity of 88%-92%;

[0026] (2) removing the vacuum, adding naphthalene and 98% sulfuric acid to the concentrated solution obtained in step (1), keeping the temperature at 130° C.-150° C. for 3 h-5 h, cooling, and crystallizing to obtain 1,6-naphthalenedisulfonic acid;

[0027] (3) The 1,6-naphthalene disulfonic acid obtained in step (2) is mixed with a sodium hydroxide solution to form a salt, thereby obtaining the sodium 1,6-naphthalene disulfonate.

[0028] That is, the present invention provides a method for producing sodium 1,6-naphthalene disulfonate using 1-naphthalenesulfonic acid reaction filtrate, comprising the steps (1) and (2), and further comprising the step (3): mixing the 1,6-naphthalene disulfonic acid obtained in step (2) with a sodium hydroxide solution to form a salt, thereby obtaining the sodium 1,6-naphthalene disulfonate.

[0029] The present invention further provides a method for producing sodium 1,6-naphthalene disulfonate by using the filtrate of the 1-naphthalenesulfonic acid reaction. The 1,6-naphthalene disulfonic acid prepared in the above step (2) is mixed with a sodium hydroxide solution to form a salt, thereby obtaining a sodium 1,6-naphthalene disulfonate product with a high purity.

[0030] Preferably, in step (3), the mass concentration of the sodium hydroxide solution is 30%.

[0031] The invention has the following beneficial effects: the invention uses the filtrate after the reaction of preparing 1-naphthalenesulfonic acid as a raw material, and through a specific preparation method, prepares 1,6-naphthalene disulfonic acid with high purity and high selectivity, and further salt formation can obtain sodium 1,6-naphthalene disulfonate. The preparation method of the invention fully utilizes the filtrate of the 1-naphthalenesulfonic acid reaction, effectively saves energy and reduces emissions, and saves production costs. The prepared 1,6-naphthalene disulfonic acid product has high purity and meets market requirements. DETAILED DESCRIPTION

[0032] To better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. It should be understood by those skilled in the art that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0033] Unless otherwise specified, the experimental methods used in the examples are all conventional methods; the materials, reagents, etc. used, unless otherwise specified, can be obtained from commercial channels.

[0034] Example 1

[0035] A method for producing 1,6-naphthalene disulfonic acid using 1-naphthalenesulfonic acid reaction filtrate comprises the following steps:

[0036] (1) The 1-naphthalenesulfonic acid reaction filtrate is pumped into a concentration kettle, heated to 130° C., and negative pressure is drawn. The pressure is controlled at -0.08 MPa and the concentrated solution is concentrated to an acidity of 90%;

[0037] (2) removing the vacuum, adding naphthalene and sulfuric acid with a mass concentration of 98% to the concentrated solution obtained in step (1), wherein the molar ratio of naphthalene to the sulfuric acid in the concentrated solution and the added sulfuric acid is 1:4, and reacting at 140° C. for 4 h. After the reaction is completed, cooling to 20° C., adding water to control the acidity to fully crystallize 1,6-naphthalenedisulfonic acid, and obtaining the 1,6-naphthalenedisulfonic acid after centrifugation.

[0038] The 1-naphthalenesulfonic acid reaction filtrate used in this embodiment includes the following components in percentage by mass: 47% water, 12% 1-naphthalenesulfonic acid, 4.9% 2-naphthalenesulfonic acid, 2.1% 1,6-naphthalenedisulfonic acid, and 36% sulfuric acid.

[0039] Example 2

[0040] A method for producing 1,6-naphthalene disulfonic acid using 1-naphthalenesulfonic acid reaction filtrate comprises the following steps:

[0041] (1) The 1-naphthalenesulfonic acid reaction filtrate is pumped into a concentration kettle, heated to 140° C., and negative pressure is drawn. The pressure is controlled at -0.07 MPa and the concentrated solution is concentrated to an acidity of 88%;

[0042] (2) removing the vacuum, adding naphthalene and sulfuric acid with a mass concentration of 98% to the concentrated solution obtained in step (1), wherein the molar ratio of naphthalene to the sulfuric acid in the concentrated solution and the added sulfuric acid is 1:3.5, and reacting at 130° C. for 5 h. After the reaction is completed, cooling to 10° C., adding water to control the acidity to fully crystallize 1,6-naphthalenedisulfonic acid, and obtaining the 1,6-naphthalenedisulfonic acid after centrifugation.

[0043] The components of the 1-naphthalenesulfonic acid reaction filtrate used in this example are the same as those in Example 1.

[0044] Example 3

[0045] A method for producing 1,6-naphthalene disulfonic acid using 1-naphthalenesulfonic acid reaction filtrate comprises the following steps:

[0046] (1) The 1-naphthalenesulfonic acid reaction filtrate is pumped into a concentration kettle, heated to 120° C., and negative pressure is drawn. The pressure is controlled at -0.095 MPa and the concentrated solution is concentrated to an acidity of 90%;

[0047] (2) removing the vacuum, adding naphthalene and sulfuric acid with a mass concentration of 98% to the concentrated solution obtained in step (1), wherein the molar ratio of naphthalene to the sulfuric acid in the concentrated solution and the added sulfuric acid is 1:4.5, and reacting at 150° C. for 3 h. After the reaction is completed, cooling to 30° C., adding water to control the acidity to fully crystallize 1,6-naphthalenedisulfonic acid, and obtaining the 1,6-naphthalenedisulfonic acid after centrifugation.

[0048] The components of the 1-naphthalenesulfonic acid reaction filtrate used in this example are the same as those in Example 1.

[0049] Example 4

[0050] A method for producing 1,6-naphthalene disulfonic acid using 1-naphthalenesulfonic acid reaction filtrate comprises the following steps:

[0051] (1) The 1-naphthalenesulfonic acid reaction filtrate is pumped into a concentration kettle, heated to 130° C., and negative pressure is drawn. The pressure is controlled at -0.08 MPa and the concentrated solution is concentrated to an acidity of 90%;

[0052] (2) removing the vacuum, adding naphthalene and sulfuric acid with a mass concentration of 98% to the concentrated solution obtained in step (1), wherein the molar ratio of naphthalene to the sulfuric acid in the concentrated solution and the added sulfuric acid is 1:3, and the reaction is carried out at 140° C. for 4 hours. After the reaction is completed, the reaction is cooled to 20° C., and water is added to control the acidity to fully crystallize 1,6-naphthalenedisulfonic acid. After centrifugation, the 1,6-naphthalenedisulfonic acid is obtained.

[0053] The 1-naphthalenesulfonic acid reaction filtrate used in this example is the same as that in Example 1.

[0054] Example 5

[0055] A method for producing 1,6-naphthalene disulfonic acid using 1-naphthalenesulfonic acid reaction filtrate comprises the following steps:

[0056] (1) The 1-naphthalenesulfonic acid reaction filtrate is pumped into a concentration kettle, heated to 130° C., and negative pressure is drawn. The pressure is controlled at -0.08 MPa and the concentrated solution is concentrated to an acidity of 90%;

[0057] (2) removing the vacuum, adding naphthalene and sulfuric acid with a mass concentration of 98% to the concentrated solution obtained in step (1), wherein the molar ratio of naphthalene to the sulfuric acid in the concentrated solution and the added sulfuric acid is 1:5, and reacting at 140° C. for 4 h. After the reaction is completed, cooling to 20° C., adding water to control the acidity to fully crystallize 1,6-naphthalenedisulfonic acid, and obtaining the 1,6-naphthalenedisulfonic acid after centrifugation.

[0058] The 1-naphthalenesulfonic acid reaction filtrate used in this example is the same as that in Example 1.

[0059] Example 6

[0060] A method for producing sodium 1,6-naphthalene disulfonate using 1-naphthalenesulfonic acid reaction filtrate comprises the following steps:

[0061] Step (1) and step (2) are the same as in Example 1 to obtain 1,6-naphthalene disulfonic acid;

[0062] (3) The 1,6-naphthalene disulfonic acid obtained in step (2) is mixed with a sodium hydroxide solution having a mass concentration of 30% to form a salt, centrifuged, and dried to obtain the sodium 1,6-naphthalene disulfonate.

[0063] Comparative Example 1

[0064] A method for producing 1,6-naphthalene disulfonic acid using 1-naphthalenesulfonic acid reaction filtrate comprises the following steps:

[0065] (1) The 1-naphthalenesulfonic acid reaction filtrate is pumped into a concentration kettle, heated to 130° C., and negative pressure is drawn. The pressure is controlled at -0.08 MPa and the concentrated solution is concentrated to an acidity of 90%;

[0066] (2) removing the vacuum, adding naphthalene and sulfuric acid with a mass concentration of 98% to the concentrated solution obtained in step (1), wherein the molar ratio of naphthalene to the sulfuric acid in the concentrated solution and the added sulfuric acid is 1:4, and reacting at 120° C. for 4 h. After the reaction is completed, cooling to 20° C., adding water to control the acidity to fully crystallize 1,6-naphthalenedisulfonic acid, and obtaining the 1,6-naphthalenedisulfonic acid after centrifugation.

[0067] The 1-naphthalenesulfonic acid reaction filtrate used in this comparative example is the same as that in Example 1.

[0068] Comparative Example 2

[0069] A method for producing 1,6-naphthalene disulfonic acid using 1-naphthalenesulfonic acid reaction filtrate comprises the following steps:

[0070] (1) The 1-naphthalenesulfonic acid reaction filtrate is pumped into a concentration kettle, heated to 130° C., and negative pressure is drawn. The pressure is controlled at -0.08 MPa and the concentrated solution is concentrated to an acidity of 90%;

[0071] (2) removing the vacuum, adding naphthalene and sulfuric acid with a mass concentration of 98% to the concentrated solution obtained in step (1), wherein the molar ratio of naphthalene to the sulfuric acid in the concentrated solution and the added sulfuric acid is 1:4, and reacting at 160° C. for 4 h. After the reaction is completed, cooling to 20° C., adding water to control the acidity to fully crystallize 1,6-naphthalenedisulfonic acid, and obtaining the 1,6-naphthalenedisulfonic acid after centrifugation.

[0072] The 1-naphthalenesulfonic acid reaction filtrate used in this comparative example is the same as that in Example 1.

[0073] Comparative Example 3

[0074] A method for producing 1,6-naphthalene disulfonic acid using 1-naphthalenesulfonic acid reaction filtrate comprises the following steps:

[0075] (1) The 1-naphthalenesulfonic acid reaction filtrate is pumped into a concentration kettle, heated to 130° C., and negative pressure is drawn. The pressure is controlled at -0.08 MPa and the concentrated solution is concentrated to an acidity of 75%;

[0076] (2) removing the vacuum, adding naphthalene and sulfuric acid with a mass concentration of 98% to the concentrated solution obtained in step (1), wherein the molar ratio of naphthalene to the sulfuric acid in the concentrated solution and the added sulfuric acid is 1:4, and reacting at 140° C. for 4 h. After the reaction is completed, cooling to 20° C., adding water to control the acidity to fully crystallize 1,6-naphthalenedisulfonic acid, and obtaining the 1,6-naphthalenedisulfonic acid after centrifugation.

[0077] The 1-naphthalenesulfonic acid reaction filtrate used in this comparative example is the same as that in Example 1.

[0078] Comparative Example 4

[0079] A method for producing 1,6-naphthalene disulfonic acid using 1-naphthalenesulfonic acid reaction filtrate comprises the following steps:

[0080] (1) The 1-naphthalenesulfonic acid reaction filtrate is pumped into a concentration kettle, heated to 130° C., and negative pressure is drawn. The pressure is controlled at -0.08 MPa and the concentrated solution is concentrated to an acidity of 95%;

[0081] (2) removing the vacuum, adding naphthalene and sulfuric acid with a mass concentration of 98% to the concentrated solution obtained in step (1), wherein the molar ratio of naphthalene to the sulfuric acid in the concentrated solution and the added sulfuric acid is 1:4, and reacting at 140° C. for 4 h. After the reaction is completed, cooling to 20° C., adding water to control the acidity to fully crystallize 1,6-naphthalenedisulfonic acid, and obtaining the 1,6-naphthalenedisulfonic acid after centrifugation.

[0082] The 1-naphthalenesulfonic acid reaction filtrate used in this comparative example is the same as that in Example 1.

[0083] Effect test:

[0084] The 1,6-naphthalenedisulfonic acid obtained in Example 1-5 and Comparative Example 1-4 was qualitatively and quantitatively tested by liquid chromatography. The test conditions of the liquid chromatography were as follows: the chromatographic column was 4.6×150 mm Extend-C18; the detection wavelength was set at 230 nm; the column temperature was set at 30° C.; the mobile phase was methanol and a mixed solution in a volume ratio of 40:60 (the mixed solution consisted of 1.0 g L -1 of ammonium acetate and 5.8 g L -1 The flow rate was set to 0.8 mL min -1 ; The detector is a UV detector; The injection volume is 10 μL. The purity and selectivity of the sample were tested by the liquid chromatography area normalization method. The test results are shown in Table 1.

[0085] Table 1 Purity and selectivity of 1,6-naphthalene disulfonic acid obtained by the methods of the examples and comparative examples

[0086] Group purity / % Selectivity / % Example 1 98.52 30.86 Example 2 97.93 43.11 Example 3 98.12 39.45 Example 4 60.74 37.58 Example 5 No crystallization 42.17 Comparative Example 1 Can't separate 28.97 Comparative Example 2 Can't separate 5.13 Comparative Example 3 No crystallization 9.64 Comparative Example 4 Black material 0

[0087] As can be seen from the results in Table 1, the preparation method of the embodiment of the present invention has higher purity and selectivity than the comparative example. The 1,6-naphthalene disulfonic acid obtained in comparative examples 1 and 2 is too little and cannot be crystallized. In comparative example 3, the acidity of the concentrated solution is too low, resulting in reduced product selectivity, many impurities, and inability to crystallize. In comparative example 4, the acidity of the concentrated solution is too high, resulting in black product material, and the target product cannot be obtained. The present invention can fully and reasonably utilize the waste liquid filtered out after the sulfonation reaction of 1-naphthalenesulfonic acid, effectively save energy and reduce emissions, and save production costs.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for producing 1,6-naphthalene disulfonic acid using 1-naphthalenesulfonic acid reaction filtrate, characterized in that: The following steps are involved: (1) heating the 1-naphthalenesulfonic acid reaction filtrate, and concentrating under reduced pressure to obtain a concentrated solution with an acidity of 88%-92%; (2) removing the vacuum, adding naphthalene and concentrated sulfuric acid to the concentrated solution obtained in step (1), keeping the temperature at 130° C.-150° C. for 3 h-5 h, cooling, and crystallizing to obtain the 1,6-naphthalenedisulfonic acid.

2. The method for producing 1,6-naphthalene disulfonic acid by utilizing 1-naphthalenesulfonic acid reaction filtrate according to claim 1, characterized in that: In the step (1), the 1-naphthalenesulfonic acid reaction filtrate comprises the following components in percentage by mass: 40%-50% of water, 10%-14% of 1-naphthalenesulfonic acid, 4%-6% of 2-naphthalenesulfonic acid, 1.5%-3% of 1,6-naphthalenedisulfonic acid, and 30%-40% of sulfuric acid.

3. The method for producing 1,6-naphthalene disulfonic acid by utilizing 1-naphthalenesulfonic acid reaction filtrate according to claim 1, characterized in that: In the step (1), the pressure during the reduced pressure concentration is -0.07Mpa to -0.095Mpa.

4. The method for producing 1,6-naphthalene disulfonic acid by utilizing 1-naphthalenesulfonic acid reaction filtrate according to claim 1, characterized in that: In the step (1), the acidity of the concentrated solution is 90%.

5. The method for producing 1,6-naphthalene disulfonic acid by utilizing 1-naphthalenesulfonic acid reaction filtrate according to claim 1, characterized in that: In the step (1), the heating temperature is 120°C-140°C.

6. The method for producing 1,6-naphthalene disulfonic acid by utilizing 1-naphthalenesulfonic acid reaction filtrate according to claim 1, characterized in that: In the step (2), the mass percentage concentration of the concentrated sulfuric acid is 98%.

7. The method for producing 1,6-naphthalene disulfonic acid by utilizing 1-naphthalenesulfonic acid reaction filtrate according to claim 1, characterized in that: In the step (2), the molar ratio of naphthalene to sulfuric acid is 1:(3-5), and the sulfuric acid includes the sulfuric acid in the concentrated solution and the concentrated sulfuric acid in the step (2).

8. The method for producing 1,6-naphthalene disulfonic acid by utilizing 1-naphthalenesulfonic acid reaction filtrate according to claim 1, characterized in that: In the step (2), the temperature of the insulation reaction is 140° C. and the time is 4 hours.

9. The method for producing 1,6-naphthalene disulfonic acid by utilizing 1-naphthalenesulfonic acid reaction filtrate according to claim 1, characterized in that: In the step (2), the temperature is cooled to 10°C-30°C.

10. A method for producing sodium 1,6-naphthalene disulfonate using 1-naphthalenesulfonic acid reaction filtrate, characterized in that: The following steps are involved: (1) heating the 1-naphthalenesulfonic acid reaction filtrate, and concentrating under reduced pressure to obtain a concentrated solution with an acidity of 88%-92%; (2) removing the vacuum, adding naphthalene and 98% sulfuric acid to the concentrated solution obtained in step (1), keeping the temperature at 130° C.-150° C. for reaction for 3 h-5 h, cooling, and crystallizing to obtain 1,6-naphthalenedisulfonic acid; (3) The 1,6-naphthalene disulfonic acid obtained in step (2) is mixed with a sodium hydroxide solution to form a salt, thereby obtaining the sodium 1,6-naphthalene disulfonate.