A method for preparing chlorinated hydrocarbons based on alcohol chlorine products

Abstract

The invention discloses a method for preparing chlorohydrocarbons based on alcohol chlorine products. In the invention, the chlorination reaction of alcohol can be efficiently realized to generate corresponding chlorohydrocarbons. Suitable primary alcohol and secondary alcohol are selected as reactants, and suitable Lewis acid catalysts AlCls and ZnCl2 are used for the chlorination reaction of alcohol to prepare chlorohydrocarbon products; the reaction and separation process conditions for preparing chlorobutane and chlorooctane are experimentally optimized to provide a basis for guiding production, the product yield reaches more than 80%, the product purity reaches more than 98%, and the conversion rate and selectivity of the reaction can be significantly improved. During the reaction process, the stability and selectivity of the reaction can be maintained by controlling the reaction temperature and pressure, and adjusting the flow rate of hydrogen chloride gas. The unreacted alcohol and hydrogen chloride gas can be recovered by using a condensation reflux device, thereby improving the atomic economy of the reaction. Through these measures, the chlorination reaction can be carried out under relatively mild conditions, thereby improving the yield and purity of chlorohydrocarbons.

Description

Technical Field

[0001] The invention belongs to the technical field of chlorohydrocarbon preparation, and specifically relates to a method for preparing chlorohydrocarbon based on alcohol chloride products. Background Art

[0002] Chlorocarbons are a class of organic compounds whose molecules contain at least one chlorine atom replacing one or more hydrogen atoms. Chlorocarbons have a wide range of applications in chemistry, industry, and medicine. There are various methods for preparing chlorinated hydrocarbons, the most common of which is the reaction of hydrochloric acid with organic compounds. For example, methyl chloride can be prepared by the reaction of hydrochloric acid with methane. Chlorocarbons can also be prepared by the reaction of chlorine with organic compounds. Chlorocarbons have a wide range of industrial applications, the most famous of which are refrigerants, such as chlorofluorocarbons (CFCs). These compounds are highly stable and non-flammable, making them widely used in refrigeration and air conditioning systems. However, due to their depleting effects on the ozone layer, their use has been gradually phased out. In addition to being refrigerants, chlorinated hydrocarbons are also used as solvents, cleaning agents, disinfectants, pesticides, fire extinguishers, and pharmaceuticals. For example, chloroform is a common chlorinated hydrocarbon. It is a colorless, transparent liquid with excellent anesthetic properties, making it widely used in surgical anesthesia. Chlorocarbons can also be used to prepare other organic compounds. For example, chlorocarbons can react with propylene to produce chloropropanes. In addition, chlorocarbons can also react with benzene to produce chlorobenzenes.

[0003] However, the common methods for preparing chlorohydrocarbons have low product yields and insufficient product purity, which cannot improve the conversion rate and selectivity of the reaction, affecting the efficiency of the overall preparation process. Summary of the Invention

[0004] The object of the present invention is to provide a method for preparing chlorinated hydrocarbons based on alcohol chloride products in order to solve the above-mentioned problems.

[0005] The technical solution adopted by the present invention is as follows: a method for preparing chlorohydrocarbons based on alcohol chloride products, the method comprising the following steps:

[0006] S1: Selecting a suitable alcohol: First, you need to select a suitable alcohol as a reactant. Generally speaking, when selecting an alcohol, you also need to consider its reactivity and stability;

[0007] S2: Prepare hydrogen chloride gas: Hydrogen chloride gas can be produced by reacting a mixture of hydrochloric acid and sulfuric acid. Hydrochloric acid is added dropwise to concentrated sulfuric acid to produce hydrogen chloride gas. The hydrogen chloride gas needs to be purified by a gas purification device to remove impurities and water vapor.

[0008] S3: Prepare Lewis acid catalyst: Select a suitable Lewis acid catalyst, such as AlCl2 or ZnCl2. Add the catalyst to the reaction system in a certain proportion. Typically, the amount of catalyst used is 5-10 mol% of the alcohol.

[0009] S4: Perform the chlorination reaction: Add an appropriate amount of alcohol and catalyst to the reaction flask, then slowly introduce hydrogen chloride gas. Maintain a stable temperature and pressure throughout the reaction, typically between room temperature and 50°C. Use a magnetic or mechanical stirrer to enhance mixing.

[0010] S5: Stop the reaction: When the reaction reaches the desired conversion rate, stop adding hydrogen chloride gas. Detect the concentration of chlorinated hydrocarbons in the reaction solution by gas chromatography or other analytical methods. If the conversion rate does not reach the expected level, continue adding hydrogen chloride gas until a satisfactory conversion rate is achieved.

[0011] S6: Separation and purification of chlorinated hydrocarbons: The reaction liquid is separated and purified. First, vacuum distillation is performed to separate the chlorinated hydrocarbons. Then, extraction or crystallization are used to further purify the chlorinated hydrocarbons. Finally, the purified chlorinated hydrocarbons are dried and packaged.

[0012] S7: Wastewater Treatment: Properly dispose of wastewater generated during the reaction. This wastewater may contain hazardous substances such as unreacted alcohol, hydrogen chloride, catalyst, and byproducts. Biodegradation, chemical oxidation, or physical adsorption can be used to treat the wastewater to minimize environmental impact, thus completing the entire chlorinated hydrocarbon production process from the alcohol-chlorinated product.

[0013] In a preferred embodiment, in step S1, a primary alcohol and a secondary alcohol are selected to undergo chlorination reaction, and the primary alcohol and the secondary alcohol include one of methanol, ethanol, n-propanol and isopropanol.

[0014] In a preferred embodiment, in step S2, first, concentrated sulfuric acid is slowly added dropwise to concentrated hydrochloric acid to avoid a violent reaction in a well-ventilated environment. The hydrogen chloride gas needs to be purified by a gas purification device to remove impurities and water vapor therein. A desiccant (such as silica gel) can be used to absorb moisture in the gas to ensure the purity of the hydrogen chloride gas.

[0015] In a preferred embodiment, in step S3, before adding the catalyst, the catalyst needs to be dried to remove moisture. The catalyst can be dried using a desiccant such as anhydrous sodium sulfate. The amount of catalyst added needs to be optimized based on experimental results to obtain the best catalytic effect.

[0016] In a preferred embodiment, in the step S4, in the chlorination process, it is necessary to control the reaction temperature and pressure to keep the stability and selectivity of the reaction. The reaction rate can be controlled by regulating the flow of hydrogen chloride gas. In the reaction process, a condensing reflux device can be used to reclaim unreacted alcohol and hydrogen chloride gas to improve the atom economy of the reaction. Simultaneously, the concentration of chlorohydrocarbons in the monitoring reaction solution can be monitored by sampling and analysis, and reaction conditions can be adjusted according to the result.

[0017] In a preferred embodiment, in step S5, the product is structurally identified by gas chromatography-mass spectrometry to ensure the purity and quality of the chlorinated hydrocarbon.

[0018] In a preferred embodiment, in the step S6, at first, most alcohol and other low-boiling impurities are removed by underpressure distillation. Then, the remaining liquid is mixed with an amount of water to form a two-phase system. Because n-butyl chloride is non-polar, a non-polar solvent such as normal hexane can be added to the mixed system, and n-butyl chloride can be preferentially distributed in the normal hexane phase. By separating the two phases with a separating funnel, the normal hexane phase containing n-butyl chloride can be obtained.

[0019] In a preferred embodiment, in the step S6, the concentration of n-butyl chloride in the solution is increased by evaporating the normal hexane, and then slowly cooled to room temperature or lower temperature to promote the crystallization of n-butyl chloride. By filtering, pure n-butyl chloride crystals can be obtained. Finally, the residual solvent in the crystal can be removed by vacuum drying to obtain highly purified n-butyl chloride.

[0020] In a preferred embodiment, in step S7, the chemical oxidation method converts the harmful substances into inorganic substances through an oxidant, which is suitable for treating waste liquid containing refractory organic matter.

[0021] In a preferred embodiment, in step S7, the physical adsorption method utilizes an adsorbent to absorb harmful substances and is suitable for removing harmful substances from wastewater. Based on the characteristics and composition of the wastewater, an appropriate treatment method is selected to reduce the impact on the environment. The biodegradation method utilizes microorganisms to convert harmful substances into harmless substances and is suitable for treating wastewater containing organic matter.

[0022] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0023] 1. The present invention efficiently chlorinates alcohols to produce the corresponding chlorohydrocarbons. By selecting appropriate primary and secondary alcohols as reactants and using a suitable Lewis acid catalyst for the alcohol chlorination reaction, the chlorohydrocarbon products are produced. Experimental optimization of the reaction and separation process conditions for preparing chlorobutane and chlorooctane provides a basis for guiding production. The product yield reaches over 80% and the product purity reaches over 98%, significantly improving the reaction conversion rate and selectivity. During the reaction, reaction temperature and pressure are controlled, as well as the flow rate of hydrogen chloride gas, to maintain reaction stability and selectivity. Furthermore, a condensing reflux system is used to recover unreacted alcohol and hydrogen chloride gas, improving the atom economy of the reaction. These measures enable the chlorination reaction to be carried out under relatively mild conditions, increasing the yield and purity of the chlorohydrocarbons.

[0024] 2. In the present invention, in the process of waste liquid treatment, various methods such as chemical oxidation, physical adsorption and biodegradation can be adopted, and the appropriate treatment method can be selected according to the characteristics and composition of the waste liquid. The chemical oxidation method converts harmful substances into harmless substances through oxidants, and is suitable for the treatment of waste liquid containing difficult-to-degrade organic matter. The physical adsorption method uses adsorbents to adsorb harmful substances, and is suitable for removing harmful substances from waste liquid. The biodegradation method uses microorganisms to convert harmful substances into harmless substances, and is suitable for the treatment of waste liquid containing organic matter. These methods can effectively reduce the impact on the environment and protect the environment from pollution by harmful substances. By properly treating waste liquid, sustainable development of the environment can be achieved, and the consumption of resources and damage to the environment can be reduced. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0026] Example:

[0027] A method for preparing chlorinated hydrocarbons based on alcohol chloride products, the method comprising the following steps:

[0028] S1: Selecting a suitable alcohol: First, you need to select a suitable alcohol as a reactant. Generally speaking, when selecting an alcohol, you also need to consider its reactivity and stability;

[0029] S2: Prepare hydrogen chloride gas: Hydrogen chloride gas can be produced by reacting a mixture of hydrochloric acid and sulfuric acid. Hydrochloric acid is added dropwise to concentrated sulfuric acid to produce hydrogen chloride gas. The hydrogen chloride gas needs to be purified by a gas purification device to remove impurities and water vapor.

[0030] S3: Prepare Lewis acid catalyst: Select a suitable Lewis acid catalyst, such as AlCl2 or ZnCl2. Add the catalyst to the reaction system in a certain proportion. Typically, the amount of catalyst used is 5-10 mol% of the alcohol.

[0031] S4: Perform the chlorination reaction: Add an appropriate amount of alcohol and catalyst to the reaction flask, then slowly introduce hydrogen chloride gas. Maintain a stable temperature and pressure throughout the reaction, typically between room temperature and 50°C. Use a magnetic or mechanical stirrer to enhance mixing.

[0032] S5: Stop the reaction: When the reaction reaches the desired conversion rate, stop adding hydrogen chloride gas. Detect the concentration of chlorinated hydrocarbons in the reaction solution by gas chromatography or other analytical methods. If the conversion rate does not reach the expected level, continue adding hydrogen chloride gas until a satisfactory conversion rate is achieved.

[0033] S6: Separation and purification of chlorinated hydrocarbons: The reaction liquid is separated and purified. First, vacuum distillation is performed to separate the chlorinated hydrocarbons. Then, extraction or crystallization are used to further purify the chlorinated hydrocarbons. Finally, the purified chlorinated hydrocarbons are dried and packaged.

[0034] S7: Wastewater Treatment: Properly dispose of wastewater generated during the reaction. This wastewater may contain hazardous substances such as unreacted alcohol, hydrogen chloride, catalyst, and byproducts. Biodegradation, chemical oxidation, or physical adsorption can be used to treat the wastewater to minimize environmental impact, thus completing the entire chlorinated hydrocarbon production process from the alcohol-chlorinated product.

[0035] In step S1, a primary alcohol and a secondary alcohol are selected to undergo a chlorination reaction, and the primary alcohol and the secondary alcohol include one of methanol, ethanol, n-propanol and isopropanol.

[0036] In step S2, first, concentrated sulfuric acid is slowly added dropwise to concentrated hydrochloric acid to avoid a violent reaction in a well-ventilated environment. The hydrogen chloride gas needs to be purified by a gas purification device to remove impurities and water vapor therein. A desiccant (such as silica gel) can be used to absorb moisture in the gas to ensure the purity of the hydrogen chloride gas.

[0037] In step S3, before adding the catalyst, the catalyst needs to be dried to remove moisture. The catalyst can be dried using a desiccant such as anhydrous sodium sulfate. The amount of catalyst added needs to be optimized based on experimental results to obtain the best catalytic effect.

[0038] In step S4, in the chlorination process, need to control reaction temperature and pressure, to keep stability and selectivity of reaction.Can control reaction rate by regulating the flow of hydrogen chloride gas.In the reaction process, can use condensing reflux device to reclaim unreacted alcohol and hydrogen chloride gas, improve the atom economy of reaction.Simultaneously, can monitor the concentration of chlorohydrocarbon in the reaction solution by sampling analysis, according to result adjustment reaction conditions.

[0039] In step S5, the product is structurally identified by gas chromatography-mass spectrometry to ensure the purity and quality of the chlorinated hydrocarbon.

[0040] In step S6, at first, most alcohol and other low-boiling impurities are removed by underpressure distillation. Then, remaining liquid is mixed with an amount of water to form a two-phase system. Because n-butyl chloride is non-polar, a non-polar solvent such as normal hexane can be added into the mixed system, and n-butyl chloride can be preferentially distributed in the normal hexane phase. Separate two phases through a separating funnel to obtain the normal hexane phase containing n-butyl chloride.

[0041] In step S6, improve the concentration of n-butyl chloride in the solution by evaporating part normal hexane, then slowly cool to room temperature or lower temperature, promote the crystallization of n-butyl chloride.By filtration, pure n-butyl chloride crystal can be obtained.Finally, the residual solvent in the crystal can be removed by vacuum drying to obtain highly purified n-butyl chloride.

[0042] In step S7, the chemical oxidation method converts harmful substances into harmless substances through an oxidant, which is suitable for treating waste liquid containing difficult-to-degrade organic matter.

[0043] In step S7, physical adsorption uses an adsorbent to absorb harmful substances and is suitable for removing harmful substances from wastewater. Depending on the characteristics and composition of the wastewater, appropriate treatment methods are selected to minimize environmental impact. Biodegradation uses microorganisms to convert harmful substances into harmless substances and is suitable for treating wastewater containing organic matter.

[0044] The present invention can efficiently carry out the chlorination reaction of alcohols to produce the corresponding chlorohydrocarbons. Suitable primary and secondary alcohols are selected as reactants, and suitable Lewis acid catalysts, such as AlCl2 and ZnCl2, are used for the chlorination reaction of the alcohols to produce the chlorohydrocarbon products. Experimental optimization of the reaction and separation process conditions for preparing chlorobutane and chlorooctane provides a basis for guiding production. The product yield reaches over 80% and the product purity reaches over 98%, significantly improving the reaction conversion rate and selectivity. During the reaction, the reaction temperature and pressure are controlled, as well as the flow rate of hydrogen chloride gas is adjusted, to maintain reaction stability and selectivity. Furthermore, a condensing reflux device is used to recover unreacted alcohol and hydrogen chloride gas, improving the atom economy of the reaction. These measures enable the chlorination reaction to be carried out under relatively mild conditions, increasing the yield and purity of the chlorohydrocarbons.

[0045] In the present invention, in the process of treating waste liquid, a variety of methods such as chemical oxidation, physical adsorption and biodegradation can be adopted, and the appropriate treatment method can be selected according to the characteristics and composition of the waste liquid. The chemical oxidation method converts harmful substances into harmless substances through an oxidant, and is suitable for treating waste liquid containing difficult-to-degrade organic matter. The physical adsorption method uses an adsorbent to adsorb harmful substances, and is suitable for removing harmful substances from waste liquid. The biodegradation method uses microorganisms to convert harmful substances into harmless substances, and is suitable for treating waste liquid containing organic matter. These methods can effectively reduce the impact on the environment and protect the environment from pollution by harmful substances. By properly treating waste liquid, sustainable development of the environment can be achieved, and the consumption of resources and damage to the environment can be reduced.

[0046] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprises" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article or device. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device that includes the element.

[0047] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing chlorinated hydrocarbons based on alcohol chloride products, characterized in that: The method comprises the following steps: S1: First, primary alcohol and secondary alcohol are selected to undergo chlorination reaction; S2: preparing hydrogen chloride gas: generating hydrogen chloride gas by reacting a mixture of hydrochloric acid and sulfuric acid; dropping hydrochloric acid into concentrated sulfuric acid to react and generate hydrogen chloride gas; purifying the hydrogen chloride gas by a gas purification device to remove impurities and water vapor therein; S3: preparing a Lewis acid catalyst: selecting a Lewis acid catalyst AlCls or ZnCl2; adding the catalyst to the reaction system in an amount of 5-10 mole percent of the alcohol; S4: Perform chlorination reaction: add alcohol and catalyst into the reaction bottle, and then introduce hydrogen chloride gas; the reaction is carried out at room temperature to 50°C; use a magnetic stirrer or a mechanical stirrer to enhance mixing; S5: When the reaction reaches the required conversion rate, stop introducing hydrogen chloride gas; and detect the concentration of chlorinated hydrocarbons in the reaction solution by gas chromatography; S6: Separation and purification of chlorinated hydrocarbons: Separation and purification of the reaction solution; first, vacuum distillation is performed to separate the chlorinated hydrocarbons; then extraction or crystallization methods are used to further purify the chlorinated hydrocarbons; finally, the purified chlorinated hydrocarbons are dried and packaged; S7: Treat the waste liquid: Use biodegradation, chemical oxidation or physical adsorption to treat the waste liquid, and then the entire process of preparing chlorinated hydrocarbons based on alcohol chlorine products can be completed.

2. A method for preparing chlorinated hydrocarbons based on alcohol chloride products as claimed in claim 1, characterized in that: In step S1, the primary alcohol and the secondary alcohol include one of methanol, ethanol, n-propanol and isopropanol.

3. A method for preparing chlorinated hydrocarbons based on alcohol chloride products as claimed in claim 1, characterized in that: In step S2, concentrated sulfuric acid is first slowly added dropwise to concentrated hydrochloric acid in a well-ventilated environment, and a silica gel desiccant is used to absorb moisture in the gas to ensure the purity of the hydrogen chloride gas.

4. A method for preparing chlorinated hydrocarbons based on alcohol chloride products as claimed in claim 1, characterized in that: In the step S3, before adding the catalyst, the catalyst needs to be dried to remove the moisture therein; anhydrous sodium sulfate desiccant is used to dry the catalyst.

5. A method for preparing chlorinated hydrocarbons based on alcohol chloride products as claimed in claim 1, characterized in that: In step S4, during the chlorination reaction, a condensation reflux device is used to recover unreacted alcohol and hydrogen chloride gas, and the concentration of chlorinated hydrocarbons in the reaction solution is monitored by sampling and analysis.

6. A method for preparing chlorinated hydrocarbons based on alcohol chloride products as claimed in claim 1, characterized in that: In step S5, if the conversion rate does not reach the expected level, the hydrogen chloride gas is continuously introduced until the expected conversion rate is reached.

7. A method for preparing chlorinated hydrocarbons based on alcohol chloride products as claimed in claim 1, characterized in that: In step S6, low-boiling impurities are first removed by reduced pressure distillation; then the remaining liquid is mixed with an appropriate amount of water to form a two-phase system; a non-polar solvent such as n-hexane is added to the mixed system, and then the two phases are separated by a separatory funnel to obtain a n-hexane phase containing n-butyl chloride.

8. A method for preparing chlorinated hydrocarbons based on alcohol chloride products as claimed in claim 1, characterized in that: In the step S6, the concentration of n-butyl chloride in the solution is increased by evaporating n-hexane, and then slowly cooled to room temperature to promote the crystallization of n-butyl chloride; to obtain pure n-butyl chloride crystals; finally, the residual solvent in the crystals is removed by vacuum drying. Obtain high-purity n-butyl chloride.