Process for synthesizing naphthol through indirect sulfonation reaction of sulfur trioxide

Abstract

The invention discloses a process for synthesizing naphthol through indirect sulfonation reaction of sulfur trioxide, which comprises the following steps: dropwise adding excessive sulfuric acid into refined naphthalene, generating naphthalene sulfonic acid through sulfonation reaction, and completely reacting naphthalene; carrying out melt crystallization on the sulfonation reaction product to obtain refined naphthalene sulfonic acid and crystallized sulfuric acid mother liquor; introducing sulfur trioxide gas into the crystallized sulfuric acid mother liquor, reacting sulfur trioxide with water to generate sulfuric acid, using the sulfuric acid for a sulfonation reaction, and realizing indirect sulfonation reaction with sulfur trioxide as the raw material; adding molten refined naphthalene sulfonic acid into a sodium sulfite mother solution, neutralizing to obtain sodium naphthalene sulfonate and sulfur dioxide, acidifying by using sulfur dioxide, carrying out alkali fusion, acidifying and rectifying to obtain 1-naphthol and 2-naphthol, and finally recovering sodium sulfite. The content of sulfuric acid in refined naphthalene sulfonic acid obtained through melt crystallization is extremely low, and the influence of sodium sulfate impurities on the alkali fusion process and the quality of byproduct sodium sulfite is avoided. In the process, the utilization rate of the raw materials naphthalene and sulfur trioxide is high, high-salt-content organic wastewater is not generated, and clean production is realized.

Description

technical field

[0001] The invention relates to the technical field of organic synthesis, in particular to a process for synthesizing naphthol through indirect sulfonation reaction of sulfur trioxide. Background technique

[0002] 1-Naphthol is commonly known as methylnaphthol, also known as α-naphthol, and it is currently mainly used as an intermediate of the pesticide carbaryl, and it can also be used as an intermediate of some drugs and fine chemical products. The main production processes of 1-naphthol are sulfonation and nitration. The sulfonation method is low-temperature sulfonation of naphthalene and sulfuric acid, and then neutralization, alkali dissolution, acidification, and rectification to obtain 1-naphthol. Since the isomers produced by sulfonation need to be removed, the product yield is low, about 40%. , The discharge of three wastes is large. The nitration method is a naphthalene nitration, reduction, and hydrolysis process. Due to the nitration reaction, ...

Examples

Embodiment 1

[0067] Synthesis of naphthol by indirect sulfonation reaction, the steps are as follows:

[0068] 1. Sulfonation: Add 258.6kg of naphthalene (99%, 2kmol) in a 2000L enamel reaction kettle, heat up to 100°C, slowly add 240L (4.4kmol) of concentrated sulfuric acid with a content of 98% into the reaction kettle dropwise, Adding time is 120 minutes, the temperature of the reaction material will rise during the dropping process, the reaction temperature is controlled at 120°C, and the temperature is raised to 130°C after the dropwise addition, and kept for 2 hours to generate naphthalenesulfonic acid. The sulfonation reaction product was sampled and analyzed, and the content of naphthalene was detected to be 0.13%.

[0069] 2. Melt crystallization: Put the sulfonation reaction product into the falling film crystallizer, and the crystallization start temperature is 120°C. Start the circulating pump to start the circulation, start cooling and crystallization, set the crystallization...

Embodiment 2

[0077] Synthesis of naphthol by indirect sulfonation reaction, the steps are as follows:

[0078] 1, sulfonation: add 258.6kg of naphthalene (99%, 2kmol) in the enamel reaction kettle of 2000L, be warming up to 100 ℃, be the sulfur trioxide absorption solution 240L (4.4kmol) of 98.51% sulfuric acid content among the embodiment 1 Slowly add it dropwise into the reaction kettle for 120 minutes, the temperature of the reaction material will rise during the dropping process, control the reaction temperature at 130°C, raise the temperature to 140°C after the dropwise addition, keep it warm for 2 hours, and generate naphthalenesulfonic acid. The sulfonation reaction product was sampled and analyzed, and the content of naphthalene was detected to be 0.08%.

[0079]2. Melting crystallization: put the sulfonation reaction product and the sweating liquid in Example 1 into the falling film crystallizer, and the crystallization start temperature is 125°C. Start the circulating pump to st...

Embodiment 3

[0087] Synthesis of naphthol by indirect sulfonation reaction, the steps are as follows:

[0088] 1, sulfonation: add the naphthalene (99%, 2kmol) of 258.6kg in the enamel reactor of 2000L, be warming up to 100 ℃, be the sulfur trioxide absorption solution 240L (4.5kmol) of the content of sulfuric acid among the embodiment 2 ) was slowly added dropwise into the reaction kettle, and the dropping time was 120 minutes. The temperature of the reaction material would rise during the dropping process, and the reaction temperature was controlled at 140°C. The sulfonation reaction product was sampled and analyzed, and the content of naphthalene was detected to be 0.05%.

[0089] 2. Melting crystallization: put the sulfonation reaction product and the sweating liquid in Example 2 into the falling film crystallizer, and the crystallization start temperature is 130°C. Start the circulation pump to start the circulation, start cooling and crystallization, set the crystallization cooling ...

technical field

[0001] The invention relates to the technical field of organic synthesis, in particular to a process for synthesizing naphthol through indirect sulfonation reaction of sulfur trioxide. Background technique

[0002] 1-Naphthol is commonly known as methylnaphthol, also known as α-naphthol, and it is currently mainly used as an intermediate of the pesticide carbaryl, and it can also be used as an intermediate of some drugs and fine chemical products. The main production processes of 1-naphthol are sulfonation and nitration. The sulfonation method is low-temperature sulfonation of naphthalene and sulfuric acid, and then neutralization, alkali dissolution, acidification, and rectification to obtain 1-naphthol. Since the isomers produced by sulfonation need to be removed, the product yield is low, about 40%. , The discharge of three wastes is large. The nitration method is a naphthalene nitration, reduction, and hydrolysis process. Due to the nitration reaction, ...

Examples

Embodiment 1

[0067] Synthesis of naphthol by indirect sulfonation reaction, the steps are as follows:

[0068] 1. Sulfonation: Add 258.6kg of naphthalene (99%, 2kmol) in a 2000L enamel reaction kettle, heat up to 100°C, slowly add 240L (4.4kmol) of concentrated sulfuric acid with a content of 98% into the reaction kettle dropwise, Adding time is 120 minutes, the temperature of the reaction material will rise during the dropping process, the reaction temperature is controlled at 120°C, and the temperature is raised to 130°C after the dropwise addition, and kept for 2 hours to generate naphthalenesulfonic acid. The sulfonation reaction product was sampled and analyzed, and the content of naphthalene was detected to be 0.13%.

[0069] 2. Melt crystallization: Put the sulfonation reaction product into the falling film crystallizer, and the crystallization start temperature is 120°C. Start the circulating pump to start the circulation, start cooling and crystallization, set the crystallization...

Embodiment 2

[0077] Synthesis of naphthol by indirect sulfonation reaction, the steps are as follows:

[0078] 1, sulfonation: add 258.6kg of naphthalene (99%, 2kmol) in the enamel reaction kettle of 2000L, be warming up to 100 ℃, be the sulfur trioxide absorption solution 240L (4.4kmol) of 98.51% sulfuric acid content among the embodiment 1 Slowly add it dropwise into the reaction kettle for 120 minutes, the temperature of the reaction material will rise during the dropping process, control the reaction temperature at 130°C, raise the temperature to 140°C after the dropwise addition, keep it warm for 2 hours, and generate naphthalenesulfonic acid. The sulfonation reaction product was sampled and analyzed, and the content of naphthalene was detected to be 0.08%.

[0079]2. Melting crystallization: put the sulfonation reaction product and the sweating liquid in Example 1 into the falling film crystallizer, and the crystallization start temperature is 125°C. Start the circulating pump to st...

Embodiment 3

[0087] Synthesis of naphthol by indirect sulfonation reaction, the steps are as follows:

[0088] 1, sulfonation: add the naphthalene (99%, 2kmol) of 258.6kg in the enamel reactor of 2000L, be warming up to 100 ℃, be the sulfur trioxide absorption solution 240L (4.5kmol) of the content of sulfuric acid among the embodiment 2 ) was slowly added dropwise into the reaction kettle, and the dropping time was 120 minutes. The temperature of the reaction material would rise during the dropping process, and the reaction temperature was controlled at 140°C. The sulfonation reaction product was sampled and analyzed, and the content of naphthalene was detected to be 0.05%.

[0089] 2. Melting crystallization: put the sulfonation reaction product and the sweating liquid in Example 2 into the falling film crystallizer, and the crystallization start temperature is 130°C. Start the circulation pump to start the circulation, start cooling and crystallization, set the crystallization cooling ...

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