Process for the production of 1,8-naphthal anhydride with co-production of manganese sulfate and 1,8-naphthal anhydride

Abstract

The application provides a 1,8-naphthalene anhydride production method for co-production of manganese sulfate, and belongs to the technical field of 1,8-naphthalene anhydride preparation. The application comprises the following steps: 1) adding water or manganese sulfate mother liquor into a sulfuric acid corrosion resistant reaction kettle, and then adjusting the concentration of sulfuric acid in the reaction kettle; 2) adding industrial acenaphthene into the reaction kettle in step 1), uniformly stirring, and then adding manganese dioxide for oxidation reaction; 3) after the reaction is completed, filtering out 1,8-naphthalene anhydride and 1,8-naphthalene anhydride crude product while hot, concentrating the filtered mother liquor to precipitate manganese sulfate, and filtering out manganese sulfate crystals and manganese sulfate mother liquor while hot; 4) mixing the 1,8-naphthalene anhydride crude product with lye, heating and stirring, filtering out insoluble substances, precipitating 1,8-naphthalene anhydride, filtering again, and drying to obtain the product 1,8-naphthalene anhydride. The application does not need special reaction equipment, and can be realized by using common fine chemical reaction equipment. Therefore, the fixed asset investment is small, and the operation is flexible.

Description

Technical Field

[0001] This invention relates to the field of 1,8-naphthalene anhydride preparation technology, and more particularly to a method for producing 1,8-naphthalene anhydride by co-producing manganese sulfate and the 1,8-naphthalene anhydride produced by this method. Background Technology

[0002] 1,8-Naphthalenedicarboxylic anhydride (abbreviated as 1,8-naphthalene anhydride) is an important chemical raw material. Based on it, a series of high-performance dyes and pigments can be synthesized (such as perylene pigments, perylene solvent dyes, perylene vat dyes, anthraquinone vat dyes, and anthraquinone pigments, etc.). It can also be used to synthesize high-performance polyimide polymer materials, fluorescent whitening agents, pesticides, and pharmaceuticals.

[0003] The earliest synthesis of this type of compound was in the early 20th century (see *Theoretical Manufacturing of Dyes Chemistry*, published in Japan in 1957). The synthesis method involved oxidizing industrial acenaphthene with acetic acid or paraffin as a solvent and sodium dichromate or potassium dichromate as an oxidant, followed by separation of 1,8-naphthalene anhydride. Currently, only three companies in China produce this product: Anshan Qicai Chemical, Shenyang Sanjiang Chemical, and Liaoyang Honggang Chemical. Their processes are essentially the same: air oxidation. Industrial acenaphthene is vaporized and mixed with an excess (approximately 20 times the theoretical amount) of air at high temperature (above 300°C) and rapidly passed through a catalyst fixed bed. The reaction products are collected by an air condenser to obtain 1,8-naphthalene anhydride, with a molar yield of 75%–80%. Approximately 20–25% of the product consists of incompletely oxidized byproducts such as acenaphthene and its polymers, as well as deeply oxidized byproducts such as oxalic acid and benzoic acid.

[0004] Manganese sulfate is an important inorganic chemical product. According to reports, my country uses approximately 60,000 tons of manganese sulfate annually as a trace element fertilizer and feed additive in agriculture and animal husbandry; while globally, approximately 220,000 tons are used annually in metallurgy and as cathode materials for new energy batteries. Currently, many factories have developed various manganese sulfate production processes tailored to local conditions. These processes often use pyrolusite as raw material, adding reducing agents such as coal powder and sulfides (e.g., sulfides used in CN101928041) to undergo a high-temperature redox reaction, converting manganese dioxide into manganese monoxide, which then reacts with sulfuric acid to produce manganese sulfate.

[0005] The separate production of 1,8-naphthalene anhydride or manganese sulfate requires specific reaction equipment, which lacks versatility and flexibility. The separate production of 1,8-naphthalene anhydride necessitates the use of specific types of blowers, vaporizers, molten salt furnaces, oxidizers, fixed catalyst beds, thin-walled air condensers, and a matching exhaust gas collection and treatment system. The separate production of manganese dioxide requires large rotary kilns and post-treatment facilities. Summary of the Invention

[0006] In view of this, and to address the aforementioned shortcomings of the existing technology, this invention provides a method for producing 1,8-naphthalene anhydride in combination with manganese sulfate. This method involves reacting industrial acenaphthene with manganese dioxide in a sulfuric acid medium to co-produce 1,8-naphthalene anhydride and manganese sulfate. The production process does not require specialized reaction equipment; ordinary fine chemical reaction equipment is sufficient. Therefore, it requires less fixed asset investment and offers flexible operation.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A method for producing 1,8-naphthalene anhydride in conjunction with manganese sulfate includes the following steps:

[0009] 1) Add water or manganese sulfate mother liquor to the sulfuric acid-resistant reactor, and then adjust the concentration of sulfuric acid in the reactor;

[0010] 2) Add industrial acenaphthene to the reaction vessel in step 1), stir evenly, and then add manganese dioxide to carry out the oxidation reaction;

[0011] 3) After the reaction is complete, add water until there are no manganese sulfate crystals in the reactor. Filter out 1,8-naphthalene anhydride and crude 1,8-naphthalene anhydride while hot. Concentrate the mother liquor to precipitate manganese sulfate. Filter while hot to obtain manganese sulfate crystals and manganese sulfate mother liquor. The manganese sulfate mother liquor can be reused in the next batch of reaction.

[0012] 4) Mix the crude 1,8-naphthalene anhydride with alkaline solution, heat and stir, filter out the insoluble matter, then precipitate 1,8-naphthalene anhydride into the mother liquor with acid, filter again, and dry to obtain the product 1,8-naphthalene anhydride.

[0013] Preferably, in step 2), after stirring evenly, the catalyst and co-catalyst are added first, and then manganese dioxide is added to carry out the reaction.

[0014] Preferably, when using the mother liquor, only the catalyst needs to be added, and the amount of the catalyst is 3% to 5% of the original amount.

[0015] Preferably, in step 1), the concentration of sulfuric acid is 30% to 90%.

[0016] Preferably, the amount of catalyst added is 0.1-5% of the industrial acenaphthene input when the mother liquor is not used.

[0017] Preferably, in step 2), the oxidation reaction temperature is 40–130°C.

[0018] Preferably, the molar ratio of manganese dioxide to industrial acenaphthene is (5:1) to (10:1).

[0019] Preferably, in step 2), the catalyst is a vanadium-containing compound, and the co-catalyst is a quaternary ammonium salt phase transfer catalyst or a polyether phase transfer catalyst.

[0020] Preferably, in step 4), the alkaline solution is at least one of carbonate and alkali metal hydroxide.

[0021] On the other hand, the present invention also provides a 1,8-naphthalene anhydride, which is produced using the above-described production method.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention provides a method for producing 1,8-naphthalene anhydride in conjunction with manganese sulfate. This method involves reacting industrial acenaphthene with manganese dioxide in a sulfuric acid medium to co-produce 1,8-naphthalene anhydride and manganese sulfate. Compared to existing processes, this method features lower reaction temperatures, more stable reaction conditions, and lower energy consumption. Unlike previous production methods, this process does not require large-scale dedicated production equipment; instead, it utilizes equipment commonly used in fine chemical industries, resulting in lower fixed asset investment and greater operational flexibility.

[0024] The present invention utilizes a method for producing 1,8-naphthalene anhydride by co-producing manganese sulfate, resulting in high yield and high purity of 1,8-naphthalene anhydride. Detailed Implementation

[0025] This invention provides a method for producing 1,8-naphthalene anhydride in conjunction with manganese sulfate, comprising the following steps:

[0026] 1) Add water or manganese sulfate mother liquor to the sulfuric acid corrosion resistant reactor, and then adjust the concentration of sulfuric acid in the reactor. The preferred substance for adjusting the sulfuric acid concentration is one or more of concentrated sulfuric acid, fuming sulfuric acid, gaseous sulfur trioxide and solid sulfur trioxide.

[0027] 2) Add industrial acenaphthene to the reaction vessel in step 1), stir evenly, and then add manganese dioxide for oxidation reaction. The preferred source of manganese dioxide is pyrolusite powder with a manganese dioxide content of 55% to 75%, manganese dioxide concentrate, and by-products of permanganate oxidation process (which contain manganese dioxide).

[0028] 3) After the reaction is complete, add water until there are no manganese sulfate crystals in the reactor. Filter out 1,8-naphthalene anhydride and crude 1,8-naphthalene anhydride while hot. Concentrate the mother liquor to precipitate manganese sulfate. Filter while hot to obtain manganese sulfate crystals and manganese sulfate mother liquor. The manganese sulfate mother liquor can be reused in the next batch of reaction.

[0029] 4) Mix the crude 1,8-naphthalene anhydride with alkaline solution, heat and stir, filter out the insoluble matter, then precipitate 1,8-naphthalene anhydride into the mother liquor with acid, filter again, and dry to obtain the product 1,8-naphthalene anhydride.

[0030] In this invention, in step 2), after stirring evenly, the catalyst and co-catalyst are added first, and then manganese dioxide is added to carry out the reaction.

[0031] In this invention, when using the mother liquor, only the catalyst needs to be added, and the amount of the catalyst is 3% to 5% of the original amount.

[0032] In this invention, in step 1), the concentration of sulfuric acid is 30% to 90%, preferably 65% ​​to 75%.

[0033] In this invention, the amount of catalyst added without using mother liquor is 0.1% to 5% of the industrial acenaphthene input, preferably 0.5% to 1%.

[0034] In this invention, in step 2), the temperature of the oxidation reaction is 40–130°C, preferably 55–75°C.

[0035] In this invention, the molar ratio of manganese dioxide to industrial acenaphthene is (5:1) to (10:1), preferably (5.75:1) to (6.58:1).

[0036] In this invention, in step 2), the catalyst is a vanadium-containing compound, and the co-catalyst is a quaternary ammonium salt phase transfer catalyst or a polyether phase transfer catalyst.

[0037] Among them, the vanadium-containing compound is preferably one or a mixture of more than one such compound, such as metavanadate, vanadium pentoxide, vanadium sulfate and vanadium hydrochloride, and the metavanadate is preferably ammonium metavanadate, potassium metavanadate and sodium metavanadate.

[0038] Quaternary ammonium salt phase transfer catalysts are preferably triethylbenzylammonium chloride, triethylbenzylammonium bromide, tetrabutylammonium bromide, etc., and polyether phase transfer catalysts are preferably polyethylene glycol dialkyl ethers, crown ethers, and cyclodextrin, etc., and one or more of them can be used in combination.

[0039] In this invention, in step 4), the alkaline solution is at least one of carbonate and alkali metal hydroxide, wherein the carbonate is preferably at least one of potassium carbonate, sodium carbonate and lithium carbonate, and the metal hydroxide is preferably any one or a mixture of sodium hydroxide and potassium hydroxide.

[0040] In this invention, the reaction vessel is preferably a reaction vessel resistant to sulfuric acid corrosion.

[0041] On the other hand, the present invention also provides a 1,8-naphthalene anhydride, which is produced by the above-described production method. The 1,8-naphthalene anhydride produced by this production method has a molar yield of more than 90% and a purity of more than 98.5%.

[0042] The technical solution of the present invention will be clearly and thoroughly explained below with reference to specific embodiments.

[0043] Example 1

[0044] 1) Add 4000 parts of water to a sulfuric acid-resistant reactor, and while stirring, slowly add 10000 parts of sulfuric acid until the concentration of sulfuric acid in the reactor is 70%;

[0045] 2) Add 1620 parts of industrial acenaphthene. After the materials are thoroughly mixed, add 15 parts of vanadium pentoxide and 65 parts of triethylbenzylammonium chloride. Cool the temperature to 65°C using circulating water.

[0046] 5300 parts of 95% recovered manganese dioxide (this manganese dioxide is a byproduct of alkyl oxidation under alkaline conditions with potassium permanganate) are slowly added to the reactor using an electric auger. A large amount of heat is released during the reaction, requiring cooling with circulating water.

[0047] 3) After the manganese dioxide was added, the reaction continued for 2 hours. A sample was taken for monitoring; after confirming the industrial acenaphthene content was less than 0.5%, 8700 parts of water were added to the reactor. The mixture was stirred until all the manganese sulfate crystals dissolved, and then filtered while hot. The filter cake was washed with water until the pH reached 4, yielding a 1,8-naphthalenedicarboxylic anhydride filter cake. The filtrate was collected, concentrated, and distilled to remove approximately half the volume of water. Then, the solution was cooled, centrifuged, filtered, and the crystals were washed with water and dried to obtain 5758 parts of manganese sulfate containing one part water of crystallization. Content: Manganese% = 31.8%. The centrifuged mother liquor and washings were collected to obtain 10320 parts of a mixed solution containing sulfuric acid, catalyst, co-catalyst, and manganese sulfate.

[0048] 4) Add the filter cake to 12,000 parts of water, stir well, then add 210 parts of 99% sodium hydroxide and 315 parts of 90% potassium hydroxide. Heat to 75°C, stir for 2 hours, and filter while hot. Rinse the filter cake with a small amount of water, combine the mother liquor and washings, and adjust the pH to 3 with sulfuric acid. After maintaining the pH at 75°C for 0.5 hours without change, filter. Dry the filter cake to obtain 1,873 parts of 1,8-naphthalenedicarboxylic anhydride, purity: 98.76%, molar yield: 94.5%.

[0049] When the mother liquor of 1,8-naphthalenedicarboxylic anhydride is reused in the refining process of the next batch of crude 1,8-naphthalenedicarboxylic anhydride filter cake, the total salt content in the mother liquor increases to more than 5.7% due to the "common ion effect," which reduces the solubility of the mother liquor in the product, and fresh water needs to be replaced.

[0050] Example 2

[0051] 10,320 parts of a mixture containing sulfuric acid, catalyst, co-catalyst, and manganese sulfate obtained in Example 1 were added to an acid-resistant reactor. While stirring, 6,500 parts of sulfuric acid and 1,620 parts of industrial acenaphthene were slowly added dropwise. After the materials were stirred evenly, 0.5 parts of vanadium pentoxide (3.33% of the amount used in Example 1) and 2.6 parts of triethylbenzylammonium chloride (4% of the amount used in Example 1) were added. All other operations were the same as in Example 1, yielding 8,455 parts of manganese sulfate monohydrate with a content of Mn% = 31.7%; 10,960 parts of the mixture containing sulfuric acid, catalyst, co-catalyst, and manganese sulfate; and 1,867 parts of 1,8-naphthalenedicarboxylic anhydride with a purity of 98.89% and a molar yield of 94.2%.

[0052] Example 3

[0053] The 10,960 parts of the mixture containing sulfuric acid, catalyst, co-catalyst, and manganese sulfate obtained in Example 2 were added to an acid-resistant reactor. While stirring, 6,500 parts of sulfuric acid and 1,620 parts of industrial acenaphthene were slowly added dropwise. After the materials were thoroughly mixed, 0.5 parts of vanadium pentoxide and 2.6 parts of triethylbenzylammonium chloride were added. All other operations were the same as in Example 1, yielding 8,560 parts of manganese sulfate monohydrate with a content of Mn% = 31.6%; 10,020 parts of the mixture containing sulfuric acid, catalyst, co-catalyst, and manganese sulfate; and 1,839 parts of 1,8-naphthalenedicarboxylic anhydride with a purity of 98.68% and a molar yield of 92.7%.

[0054] Example 4

[0055] Add 4000 parts of water to an acid-resistant reactor. While stirring, slowly add 10000 parts of sulfuric acid and 1620 parts of industrial acenaphthene. After the materials are thoroughly mixed, add 16 parts of the main catalyst ammonium metavanadate and 60 parts of the co-catalyst 18-crown 6-cyclic crown ether. Cool the temperature to 65°C using circulating water. Slowly add 8500 parts of pyrolusite powder containing 60% manganese dioxide to the reactor using an electric auger. All other operations are the same as in Example 1.

[0056] 5855 parts of manganese sulfate containing one molecule of water of crystallization were obtained. Content: Manganese % = 31.3%. The mother liquor and washings were collected by centrifugation to obtain 9860 parts of a mixture containing sulfuric acid, catalyst, co-catalyst, and manganese sulfate. 1786 parts of 1,8-naphthalenedicarboxylic anhydride were obtained, with a purity of 98.63% and a molar yield of 90.0%.

[0057] Example 5

[0058] The 9860 parts of the mixture containing sulfuric acid, catalyst, co-catalyst, and manganese sulfate obtained in Example 4 were added to an acid-resistant reactor. While stirring, 6500 parts of sulfuric acid and 1620 parts of industrial acenaphthene were slowly added dropwise. After the materials were stirred evenly, 0.6 parts of ammonium metavanadate and 3 parts of the co-catalyst 18-crown 6-cyclic crown ether were added. All other operations were the same as in Example 4, yielding 8505 parts of manganese sulfate monohydrate with a content of Mn% = 31.4%; 9953 parts of the mixture containing sulfuric acid, catalyst, co-catalyst, and manganese sulfate; and 1795 parts of 1,8-naphthalenedicarboxylic anhydride with a purity of 98.89% and a molar yield of 90.5%.

[0059] Example 6

[0060] The 9953 parts of the mixture containing sulfuric acid, catalyst, co-catalyst, and manganese sulfate obtained in Example 5 were added to an acid-resistant reactor. While stirring, 6500 parts of sulfuric acid and 1620 parts of industrial acenaphthene were slowly added dropwise. After the materials were thoroughly mixed, 0.6 parts of ammonium metavanadate and 3 parts of the co-catalyst 18-crown 6-cyclic crown ether were added. All other operations were the same as in Example 4, yielding 8673 parts of manganese sulfate monohydrate with a content of Mn% = 31.5%; 10730 parts of the mixture containing sulfuric acid, catalyst, co-catalyst, and manganese sulfate; and 1789 parts of 1,8-naphthalenedicarboxylic anhydride with a purity of 98.72% and a molar yield of 90.2%.

[0061] The above are merely preferred embodiments of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concept, should be covered within the scope of protection of the present invention.

Claims

1. A method for producing 1,8-naphthalene anhydride in conjunction with manganese sulfate, characterized in that, Includes the following steps: 1) Add water or manganese sulfate mother liquor to the sulfuric acid-resistant reactor, and then adjust the concentration of sulfuric acid in the reactor; 2) Add industrial acenaphthene to the reaction vessel in step 1), stir evenly, add the catalyst and co-catalyst first, and then add manganese dioxide to react; wherein, the catalyst is one or a mixture of more than one of metavanadate, vanadium pentoxide, vanadium sulfate and vanadium hydrochloride, and the co-catalyst is triethylbenzylammonium chloride, triethylbenzylammonium bromide, tetrabutylammonium bromide, polyethylene glycol dialkyl ether, crown ether and cyclodextrin, and one or more of them can be selected and mixed. 3) After the reaction is complete, add water until there are no manganese sulfate crystals in the reactor. Filter out 1,8-naphthalene anhydride and crude 1,8-naphthalene anhydride while hot. Concentrate the mother liquor to precipitate manganese sulfate. Filter while hot to obtain manganese sulfate crystals and manganese sulfate mother liquor. The manganese sulfate mother liquor can be reused in the next batch of reaction. 4) Mix the crude 1,8-naphthalene anhydride with alkaline solution, heat and stir, filter out the insoluble matter, then precipitate 1,8-naphthalene anhydride into the mother liquor with acid, filter again, and dry to obtain the product 1,8-naphthalene anhydride.

2. The method for producing 1,8-naphthalene anhydride in conjunction with manganese sulfate according to claim 1, characterized in that, When using the mother liquor, only the catalyst needs to be added, and the amount of the catalyst is 3% to 5% of the original amount.

3. The method for producing 1,8-naphthalene anhydride in conjunction with manganese sulfate according to claim 1, characterized in that, In step 1), the concentration of sulfuric acid is 30% to 90%.

4. The method for producing 1,8-naphthalene anhydride in conjunction with manganese sulfate according to claim 1, characterized in that, Without using the mother liquor, the amount of catalyst added is 0.1-5% of the industrial acenaphthene input.

5. The method for producing 1,8-naphthalene anhydride in conjunction with manganese sulfate according to claim 1, characterized in that, In step 2), the oxidation reaction temperature is 40–130°C.

6. The method for producing 1,8-naphthalene anhydride in conjunction with manganese sulfate according to claim 1, characterized in that, The molar ratio of manganese dioxide to industrial acenaphthene is (5:1) to (10:1).

7. A method for producing 1,8-naphthalene anhydride in conjunction with manganese sulfate according to any one of claims 1-6, characterized in that, In step 4), the alkaline solution is at least one of carbonate and alkali metal hydroxide.