Method for high-purity catalytic synthesis of benzodioxole

Abstract

The invention provides a method for high-purity catalytic synthesis of benzodioxole, and belongs to the technical field of chemical engineering. According to the technical scheme, catechol and dichloromethane serve as main raw materials, firstly, catechol and alkali liquor are prepared into mixed liquor, and the mixed liquor reacts under the action of a phase transfer catalyst; after the temperature and pressure maintaining reaction is finished, an azeotrope of crude oil and water is obtained through distillation, and then the product benzodioxole is obtained through layering, washing and reduced pressure distillation. Material reaction is carried out under medium pressure, generation of a large amount of waste gas can be completely eradicated, and pollution of the waste gas to the environment is avoided; meanwhile, benefited from the optimization of the process and the improvement of reaction parameters and separation conditions, the output of the wastewater is greatly reduced, and the generated wastewater can be recycled after being treated, so that the pollution is reduced, the production cost is reduced, and the economic benefit is improved. The method fully solves a series of problems of long production period, low conversion rate and yield, serious environmental pollution, high production cost and the like in the production of the benzodioxole.

Description

Technical Field

[0001] This invention belongs to the field of chemical technology, specifically a method for high-purity catalytic synthesis of piperine rings. Background Technology

[0002] Piperidine, a pale yellow, transparent liquid, is also known as 1,3-benzodioxane; methylenedioxybenzene; methylbenzene dioxybenzene; catechol methyl ether; 1,2-methylenedioxybenzene; and catechol methylene ether. Piperidine is an important organic synthesis intermediate, used in the production of fragrances, pharmaceuticals, and pesticides. For example, in the pharmaceutical industry, it can be used to synthesize miloxacin and oxolinic acid.

[0003] The common production process for piperonyl rings uses catechol and thionyl chloride as raw materials. This process is cumbersome and inefficient, with a long production cycle, poor quality, and significant air pollution from the large amount of waste gas produced. The product yield is only about 46%, which is low, and the product content is only around 60%, which is also low. The reaction equipment in the traditional process is relatively outdated and the material reaction is carried out at atmospheric pressure, generating a large amount of waste gas and causing environmental pollution. Moreover, the traditional process generates a large amount of wastewater during production due to inadequate material selection, separation conditions, and post-treatment facilities. Summary of the Invention

[0004] This invention aims to address the technical deficiencies of existing technologies by providing a method for high-purity catalytic synthesis of piperonyl, thereby solving the technical problem that current common piperonyl production processes generate large amounts of waste gas and wastewater, causing environmental pollution.

[0005] Another technical problem that this invention aims to solve is: how to improve the content and yield of the product through improvements in the synthesis method.

[0006] Another technical problem that this invention aims to solve is: how to simplify the process, improve process efficiency, and shorten the production cycle through improvements in the synthesis method.

[0007] Another technical problem that this invention aims to solve is: how to reduce production costs and improve economic efficiency through improvements in synthesis methods.

[0008] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0009] A method for high-purity catalytic synthesis of piperine rings includes: mixing liquid alkali and catechol, heating and stirring until completely dissolved to obtain a feed solution; adding a phase transfer catalyst and dichloromethane to a reaction vessel, heating to 90-110°C, feeding the feed solution into the reaction vessel, maintaining the temperature for reaction after feeding, then cooling to room temperature, performing atmospheric distillation on the reaction solution to recover dichloromethane, then heating to distill off the azeotrope of crude oil and water, allowing it to stand and separate into layers to obtain crude oil, performing vacuum distillation on the crude oil at a distillation vessel temperature of 100-105°C, and collecting the product in the gas phase at 80-85°C.

[0010] Preferably, the phase transfer catalyst is tetrabutylammonium bromide.

[0011] Preferably, the liquid alkali is a sodium hydroxide solution.

[0012] Preferably, the reactor is a high-pressure reactor.

[0013] Preferably, the feed liquid is pumped into the reactor by a metering pump.

[0014] Preferably, the mass ratio of liquid alkali to catechol is 2:1.

[0015] Preferably, the duration of the heat preservation reaction is 3 hours.

[0016] Preferably, the cooling is achieved through circulating water cooling.

[0017] Preferably, the reactor is a stainless steel reactor.

[0018] As a preferred option, the wastewater generated is pretreated and then recycled after triple-effect distillation.

[0019] This invention provides a method for the high-purity catalytic synthesis of piperine rings. The technical solution uses catechol and dichloromethane as the main raw materials. First, catechol and alkaline solution are mixed and reacted under the action of a phase transfer catalyst. After the reaction is carried out under heat and pressure, an azeotrope of crude oil and water is obtained by distillation. This azeotrope is then separated, washed, and distilled under reduced pressure to obtain the product, piperine rings. This invention uses a stainless steel reactor and a metering pump to feed the materials into the reactor, making the feeding ratio more accurate. Furthermore, the process uses medium pressure for the material reaction, which eliminates the generation of large amounts of waste gas and avoids environmental pollution. Simultaneously, thanks to process optimization and improvements in reaction parameters and separation conditions, the amount of wastewater generated is significantly reduced. The generated wastewater can be recycled after pretreatment and triple-effect distillation, thus reducing pollution, lowering production costs, and improving economic efficiency. This invention effectively solves a series of problems existing in the production of piperine rings, such as long production cycles, low conversion and yield rates, serious environmental pollution, and high production costs. Detailed Implementation

[0020] The specific embodiments of the present invention will be described in detail below. To avoid excessive and unnecessary detail, well-known structures or functions will not be described in detail in the following embodiments. The approximate language used in the following embodiments is for quantitative purposes, indicating that a certain degree of variation in quantity is permissible without changing the basic function. Unless otherwise defined, the technical and scientific terms used in the following embodiments have the same meaning as commonly understood by those skilled in the art to which this invention pertains.

[0021] A method for high-purity catalytic synthesis of piperine rings:

[0022] Liquid alkali and catechol were added to a flask, and the mixture was heated and stirred until completely dissolved. Tetrabutylammonium bromide catalyst and dichloromethane were added to a high-pressure reactor, ensuring no leaks. The temperature was raised to 100°C, and the metering pump was turned on to start feeding. After feeding, the feed line was flushed with water, and the reaction was maintained at this temperature for 3 hours. After the reaction was completed, the mixture was cooled to room temperature. The reaction solution from the high-pressure reactor was added to the flask, and the temperature was raised to recover the dichloromethane. After the dichloromethane was recovered, the temperature was gradually increased to distill off the azeotrope of crude oil and water. Once no stratification was observed in the distillate, the distillation was complete, and the crude oil was separated by settling. The washed crude oil was then subjected to vacuum distillation at a distillation vessel temperature of 100-105°C and an ambient temperature of 80-85°C. The product was collected.

[0023] Example 1

[0024] Add 800g of liquid alkali and 400g of catechol to a flask, heat and stir until the materials are completely dissolved. Add tetrabutylammonium bromide and dichloromethane to a high-pressure reactor, heat to 90℃, and start feeding with a metering pump. After feeding is complete, maintain the reaction temperature for 3 hours, and allow the circulating water to cool to room temperature. Pour the reaction solution into a flask and recover the dichloromethane by atmospheric distillation. After the dichloromethane is recovered, gradually increase the temperature to distill off the azeotrope of crude oil and water. Allow the mixture to stand and separate into layers to obtain the crude oil. Perform vacuum distillation on the crude oil at a distillation vessel temperature of 105℃ and a vapor phase temperature of approximately 85℃. Collect the product. Purity: 99.99%, Yield: 82%.

[0025] Example 2

[0026] Add 800g of liquid alkali and 400g of catechol to a flask, heat and stir until the materials are completely dissolved. Add tetrabutylammonium bromide and dichloromethane to a high-pressure reactor, heat to 100℃, start feeding with a metering pump, and maintain the reaction temperature for 3 hours after feeding is complete, while the circulating water is cooled to room temperature. Pour the reaction solution into a flask and recover the dichloromethane by atmospheric distillation. After the dichloromethane is recovered, gradually increase the temperature to distill off the azeotrope of crude oil and water, and allow it to stand to separate the layers, separating the crude oil. Perform vacuum distillation on the crude oil at a distillation vessel temperature of 105℃ and a vapor phase temperature of approximately 85℃, collecting the product. Purity: 99.99%, Yield: 90%.

[0027] Example 3

[0028] Add 800g of liquid alkali and 400g of catechol to a flask, heat and stir until the materials are completely dissolved. Add tetrabutylammonium bromide and dichloromethane to a high-pressure reactor, heat to 110℃, and start feeding with a metering pump. After feeding is complete, maintain the reaction temperature for 3 hours, and allow the circulating water to cool to room temperature. Pour the reaction solution into a flask and recover the dichloromethane by atmospheric distillation. After the dichloromethane is recovered, gradually increase the temperature to distill off the azeotrope of crude oil and water. Allow the mixture to stand and separate into layers to obtain the crude oil. Perform vacuum distillation on the crude oil at a distillation vessel temperature of 105℃ and a vapor phase temperature of approximately 85℃. Collect the product. Purity: 99.95%, Yield: 86%.

[0029] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the scope of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for high-purity catalytic synthesis of piperine rings, characterized in that, include: Liquid alkali and catechol are mixed and heated until completely dissolved to obtain a feed solution. A phase transfer catalyst and dichloromethane are added to a reaction vessel, and the temperature is raised to 90-110°C. The feed solution is then fed into the reaction vessel. After feeding is complete, the reaction is maintained at this temperature, and then cooled to room temperature. The reaction solution is then distilled at atmospheric pressure to recover dichloromethane. The azeotrope of crude oil and water is then distilled off, and the mixture is allowed to stand and separate into layers to obtain crude oil. The crude oil is then subjected to vacuum distillation at a distillation vessel temperature of 100-105°C, and the product is collected in the gas phase at 80-85°C.

2. The method for high-purity catalytic synthesis of piperine rings according to claim 1, characterized in that, The phase transfer catalyst is tetrabutylammonium bromide.

3. The method for high-purity catalytic synthesis of piperine rings according to claim 1, characterized in that, The liquid alkali is a sodium hydroxide solution.

4. The method for high-purity catalytic synthesis of piperine rings according to claim 1, characterized in that, The reactor is a high-pressure reactor.

5. The method for high-purity catalytic synthesis of piperine rings according to claim 1, characterized in that, The feed liquid is pumped into the reactor by a metering pump.

6. The method for high-purity catalytic synthesis of piperine rings according to claim 1, characterized in that, The mass ratio of liquid alkali to catechol is 2:

1.

7. The method for high-purity catalytic synthesis of piperine rings according to claim 1, characterized in that, The duration of the heat preservation reaction is 3 hours.

8. The method for high-purity catalytic synthesis of piperine rings according to claim 1, characterized in that, The cooling is achieved through circulating water cooling.

9. The method for high-purity catalytic synthesis of piperine rings according to claim 1, characterized in that, The reactor is a stainless steel reactor.

10. The method for high-purity catalytic synthesis of piperine rings according to claim 1, characterized in that, Also includes: The wastewater generated is pretreated and then recycled after triple-effect distillation.