Method for synthesizing chlorinated n-butane

Abstract

The invention relates to a method for synthesizing chlorinated n-butane, which comprises the following steps of: adding n-butyl alcohol and hydrochloric acid into a synthesis kettle according to a mass ratio of 1: 1.6-1: 1.7, and carrying out constant-temperature reaction at 90-100 DEG C under normal pressure; after the reaction is finished, feeding a synthetic reaction material into a distillation tower, feeding a distilled crude chlorobutane product and water into a water segregator for phase separation, overflowing the crude chlorobutane product from an upper opening of the water segregator, feeding the crude chlorobutane product into a crude product tank, and enabling water to flow into a wastewater recovery tank from a lower opening of the water segregator; feeding the crude chlorobutane product into a rectifying tower for rectification and purification, enabling the rectified chlorobutane to flow into a reflux tank, enabling the rectified chlorobutane to flow into a storage tank after being sampled and analyzed to be qualified, and continuously feeding the unqualified chlorobutane into the rectifying tower for repeated rectification until the unqualified chlorobutane is qualified; and carrying out acid washing, alkali washing and water washing on the qualified chlorobutane after rectification to obtain a chlorinated n-butane product. According to the method disclosed by the invention, the chlorinated n-butane can be continuously produced without adding any chemical agent, the operation method is simple, the cost is low, the product yield is high, the purity of the obtained chlorinated n-butane product is greater than 99.5%, and the impurity content of n-butyl alcohol and dibutyl ether is low.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of organotin series chemicals, and in particular relates to a method for synthesizing n-butyl chloride. Background Art

[0002] Chlorobutylene is also known as 1-chlorobutane. Its chemical formula is C4H9Cl. It is a colorless liquid with volatility. Its vapor will form an explosive mixture when it meets air. It will cause combustion and explosion when it meets open flames and high heat. It is almost insoluble in water (the solubility in water at 12°C is 0.066%), but soluble in ethanol and ether. Melting point -123°C, boiling point 77-78°C (101.325kPa), flash point -12°F, relative density 0.886g / ml (25°C), refractive index n 20 D 1.402 is an important monohalogenated alkane and organic chemical raw material. It is usually obtained by the reaction of n-butanol and hydrogen chloride. It can be used as a solvent, can also be used in organic synthesis, and can also be used to make butyl cellulose, insect repellents, etc. In addition, it is also used in oils, rubbers, natural resin solvents, pharmaceutical intermediates and co-catalysts. In the pharmaceutical field, it can be used to prepare phenylbutazone, and in the pesticide field, it can be used to prepare insecticides such as myclobutanil. The traditional method of synthesizing n-chlorobutane has various problems, such as: complex equipment, high production cost, high heavy metal ion content in wastewater caused by the introduction of catalysts, long reaction time and low yield. Therefore, the development of a method for synthesizing n-chlorobutane with simple process, reasonable cost, safety and environmental protection is a major demand for the current production of organic chemicals. Summary of the invention

[0003] The object of the present invention is to provide a method for synthesizing n-butyl chloride which is simple to operate, low in cost, capable of continuous production and has high product yield.

[0004] The technical solution adopted by the present invention is as follows: A method for synthesizing n-butyl chloride, characterized in that it comprises the following steps: (1) adding n-butanol and hydrochloric acid into a synthesis reactor at a mass ratio of 1:1.6-1:1.7, and carrying out a constant temperature reaction at 90-100°C under normal pressure; (2) After the reaction is completed, the synthetic reaction materials are sent to a distillation tower for distillation, and the distilled crude n-butyl chloride and water are sent to a water separator for phase separation. The crude n-butyl chloride overflows from the upper opening of the water separator and is sent to a crude product tank, and the water flows from the lower opening of the water separator into a wastewater recovery tank; (3) The crude chlorobutane is sent to a distillation tower for distillation and purification. The distillation boiling range is 77-79°C. The chlorobutane after distillation flows into a reflux tank. After sampling and analysis, it flows into a storage tank. The unqualified chlorobutane continues to be sent to the distillation tower for repeated distillation until it is qualified. (4) The qualified chlorobutane is subjected to acid washing, alkali washing and water washing to obtain the chlorobutylene product.

[0005] Furthermore, the mass concentration of the hydrochloric acid in step (1) is 35%.

[0006] Furthermore, the distillation tower described in step (2) is a constant boiling distillation tower, the bottom temperature of the tower is 80-100°C, and the top temperature of the tower is 70-72°C.

[0007] Furthermore, in step (2), the water flowing into the wastewater recovery tank from the lower outlet of the water separator is sent to a distillation tower to recover n-butanol, and the recovered n-butanol is returned to the synthesis reactor of step (1) to continue to participate in the reaction.

[0008] Furthermore, the pickling in step (3) is performed twice using hydrochloric acid with a mass concentration of 30%, with each washing lasting 60 minutes and then standing for 30 minutes.

[0009] Furthermore, the alkaline washing in step (3) is performed once using a sodium hydroxide solution with a mass concentration of 40%, washing for 60 minutes, and standing for 60 minutes.

[0010] Furthermore, the water washing in step (3) is performed once, for 60 minutes, and then left to stand for 30 minutes.

[0011] The present invention has at least the following advantages: (1) The method of the present invention can continuously produce n-butyl chloride without adding any chemical agent, has a simple operation method, low cost, and high product yield. At the same time, it can effectively reduce the generation of by-products, improve production safety, reduce recovery pressure, and avoid new pollution factors.

[0012] (2) The method of the present invention uses a constant temperature distillation tower, a water separator and a distillation tower for continuous operation. After the material distilled out in the constant temperature distillation tower is separated into layers in the water separator, the mixture in the lower layer enters the distillation tower, and the azeotrope formed by n-butanol and a small amount of water is distilled out and then returned to the reactor to further participate in the reaction as a reactant, thereby promoting the reaction to proceed in the forward direction, which can effectively reduce the amount of wastewater, the acid content of the product and the amount of by-product dibutyl ether produced. The purity of the n-butyl chloride product synthesized by the reaction is greater than 99.5%, the impurity contents of n-butanol and dibutyl ether are low, and the n-butanol content is less than 0.1%. DETAILED DESCRIPTION

[0013] The present invention is further described in detail below in conjunction with specific embodiments. It should be understood by those skilled in the art that the embodiments are only a description of the present invention, rather than a limitation on the protection scope of the present invention. Example 1

[0014] A method for synthesizing n-butyl chloride is provided, wherein 805 kg of n-butyl alcohol and 1360 kg of hydrochloric acid with a mass concentration of 35% are put into a reactor, steam is passed to heat the mixture, and the temperature in the reactor reaches 90-100° C. After the synthesis reaction is completed, the material is transferred to a distillation tower, and the synthesis reaction material is distilled at normal pressure, a reactor temperature of 80-100° C., and a tower top temperature of 70-72° C. At this time, the generated n-butyl chloride, water, part of the unreacted n-butyl alcohol, and a small amount of hydrochloric acid are evaporated together and separated into layers in a water separator. The lower layer of wastewater after separation in the water separator is sent to the plant wastewater treatment system, and the crude n-butyl chloride separated from the upper layer is sent to a distillation tower for distillation and purification, and the distillation boiling range is 77-79° C. The distilled butyl chloride flows into a reflux tank, and flows into a storage tank after sampling and analysis. The unqualified butyl chloride is continuously sent to the distillation tower for repeated distillation until it is qualified. Then, the qualified chlorobutylene was transferred to the washing kettle, washed twice with the same volume of 30% hydrochloric acid, each washing for 60 minutes, and left to stand for 30 minutes. Then, it was washed with the same volume of 40% sodium hydroxide solution for 60 minutes, left to stand for 60 minutes, then washed with industrial water for 60 minutes, left to stand for 30 minutes, and then separated. The lower layer of water was discharged from the bottom to the factory wastewater treatment system, and the upper layer of qualified products was sent to the chlorobutylene product tank. The final product was tested by gas chromatography and contained 99.67% chlorobutylene, 0.118% 2-chlorobutylene, 0.038% n-butanol, and 0.003% dibutyl ether. Example 2

[0015] A method for synthesizing n-butyl chloride comprises the following steps: putting 430 kg of n-butyl alcohol and 670 kg of hydrochloric acid with a concentration of 35% into a reaction kettle, passing steam to heat the mixture so that the temperature in the kettle reaches 90-100° C. After the synthesis reaction is completed, the materials are transferred to a distillation tower, and the synthesis reaction materials are distilled at normal pressure, a kettle temperature of 80-100° C., and a tower top temperature of 70-72° C. At this time, the generated n-butyl chloride, water, part of the unreacted n-butyl alcohol and a small amount of hydrochloric acid are distilled out together and separated into layers in a water separator. The lower layer of wastewater is sent to the plant wastewater treatment system, and the crude n-butyl chloride separated from the upper layer is transported to the distillation tower for distillation and purification. The distillation boiling range is 77~79℃. The distilled butyl chloride flows into the reflux tank, and flows into the storage tank after sampling and analysis. The unqualified butyl chloride continues to be sent to the distillation tower for repeated distillation until it is qualified; then the qualified n-butyl chloride is transferred to the water washing kettle, washed twice with the same volume of 30% hydrochloric acid, each washing for 60 minutes, and left to stand for 30 minutes. Then use the same volume of 40% sodium hydroxide solution for alkali washing for 60 minutes, stand for 60 minutes, then wash with industrial water for 60 minutes, stand for 30 minutes, and then separate the layers. The lower layer of water is discharged from the bottom to the plant wastewater treatment system, and the upper layer of qualified products is sent to the n-butyl chloride product tank. The final product was detected by gas chromatography and contained 99.73% of n-butyl chloride, 0.115% of 2-chlorobutane, 0.042% of n-butanol and 0.004% of dibutyl ether. Example 3

[0016] A method for synthesizing n-butyl chloride comprises the following steps: adding 632 kg of n-butyl alcohol and 1074 kg of hydrochloric acid with a concentration of 35% into a reaction kettle, passing steam to heat the mixture so that the temperature in the kettle reaches 90-100° C. After the synthesis reaction is completed, the materials are transferred into a distillation tower, and the synthesis reaction materials are distilled at normal pressure, a kettle temperature of 80-100° C., and a tower top temperature of 70-72° C. At this time, the generated n-butyl chloride, water, part of the unreacted n-butyl alcohol and a small amount of hydrochloric acid are distilled out together and separated into layers in a water separator. The lower layer of wastewater is sent to the plant wastewater treatment system, and the crude n-butyl chloride separated from the upper layer is transported to the distillation tower for distillation and purification. The distillation boiling range is 77~79℃. The distilled butyl chloride flows into the reflux tank, and flows into the storage tank after sampling and analysis. The unqualified butyl chloride continues to be sent to the distillation tower for repeated distillation until it is qualified; then the qualified n-butyl chloride is transferred to the water washing kettle, washed twice with the same volume of 30% hydrochloric acid, each washing for 60 minutes, and left to stand for 30 minutes. Then use the same volume of 40% sodium hydroxide solution for alkali washing for 60 minutes, stand for 60 minutes, then wash with industrial water for 60 minutes, stand for 30 minutes, and then separate the layers. The lower layer of water is discharged from the bottom to the plant wastewater treatment system, and the upper layer of qualified products is sent to the n-butyl chloride product tank. The product was tested by gas chromatography and found to contain 99.78% n-butyl chloride, 0.113% 2-chlorobutane, 0.036% n-butanol and 0.002% dibutyl ether.

[0017] The equipment used in the method of the present invention, such as the reaction kettle, distillation tower, rectification tower, etc., are all prior art equipment.

[0018] Unless otherwise specified, all percentages described in the present invention are by mass percentages.

Claims

1. A method for synthesizing n-butyl chloride, characterized in that: The following steps are involved: (1) adding n-butanol and hydrochloric acid into a synthesis reactor at a mass ratio of 1:1.6-1:1.7, and carrying out a constant temperature reaction at 90-100°C under normal pressure; (2) After the reaction is completed, the synthetic reaction materials are sent to a distillation tower for distillation, and the distilled crude n-butyl chloride and water are sent to a water separator for phase separation. The crude n-butyl chloride overflows from the upper opening of the water separator and is sent to a crude product tank, and the water flows from the lower opening of the water separator into a wastewater recovery tank; (3) The crude chlorobutane is sent to a distillation tower for distillation and purification. The distillation boiling range is 77-79°C. The chlorobutane after distillation flows into a reflux tank. After sampling and analysis, it flows into a storage tank. The unqualified chlorobutane continues to be sent to the distillation tower for repeated distillation until it is qualified. (4) The qualified chlorobutane is subjected to acid washing, alkali washing and water washing to obtain the chlorobutylene product.

2. A method for synthesizing n-butyl chloride as claimed in claim 1, characterized in that: The mass concentration of hydrochloric acid in step (1) is 35%.

3. The method of a method for synthesizing n-butyl chloride as claimed in claim 1, characterized in that: The distillation tower described in step (2) is a constant boiling distillation tower, the bottom temperature of the tower is 80-100°C, and the top temperature of the tower is 70-72°C.

4. The method of a method for synthesizing n-butyl chloride as claimed in claim 1, characterized in that: In step (2), the water flowing into the wastewater recovery tank from the lower outlet of the water separator is sent to the distillation tower to recover n-butanol, and the recovered n-butanol is returned to the synthesis reactor of step (1) to continue to participate in the reaction.

5. A method for synthesizing n-butyl chloride as claimed in claim 1, characterized in that: The pickling in step (3) is performed twice using hydrochloric acid with a mass concentration of 30%, with each washing lasting 60 minutes and then standing for 30 minutes.

6. A method for synthesizing n-butyl chloride as claimed in claim 1, characterized in that: The alkaline washing in step (3) is performed by using a sodium hydroxide solution with a mass concentration of 40%, washing for 60 minutes, and standing for 60 minutes.

7. A method for synthesizing n-butyl chloride as claimed in claim 1, characterized in that: The water washing in step (3) is performed once, for 60 minutes, and then left to stand for 30 minutes.