A method for synthesizing 2,2'-dichlorodiethyl ether

Abstract

The application discloses a synthesis method of 2,2'-dichloroethyl ether, and specifically comprises the following steps: under the condition of 70-80 DEG C, hydrogen chloride gas is introduced into a reaction kettle containing diethylene glycol and a catalyst; the temperature is continuously increased to 95-98 DEG C, and reaction is carried out for 3-5 hours; after temperature reduction, excessive hydrogen chloride gas is removed through negative pressure distillation; then, vacuum rectification is carried out; and when the tower top temperature is 68-70 DEG C, the fraction is 2,2'-dichloroethyl ether. In the application, hydrogen chloride gas is used as a chlorinating agent, diethylene glycol is subjected to double substitution chlorination reaction under the action of a composite catalyst composed of an organic carboxylic acid and a Lewis acid, and 2,2'-dichloroethyl ether is synthesized; the catalyst has good catalytic performance, can effectively prevent the breakage of ether bonds, and has high product yield; the method has the advantages of easy raw material acquisition, simple synthesis process, small environmental pollution, small production cost and easy industrialization.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of organic intermediate synthesis, in particular to a preparation method of dichloroether, an intermediate for synthesizing an oxygen-containing bactericide. BACKGROUND

[0002] In the industrial circulating cooling water treatment process, a certain amount of bactericides is usually added to control the generation of microorganisms and the reproduction of algae. According to the bactericidal mechanism, bactericides can be divided into oxidizing type and non-oxidizing type. Oxidizing type bactericides include halogen-containing compounds, peroxides, etc.; non-oxidizing type bactericides are mostly organic compounds. In actual production and application, oxidizing type bactericides are more convenient and effective than non-oxidizing type bactericides, but they are prone to cause microbial resistance and have an impact on the environment due to their residues and decomposition products. For a long time, quaternary ammonium salt bactericides have been favored by the domestic and foreign water treatment industry due to their good bactericidal and algae-killing performance and mud peeling effect, but they have a large amount of use and produce a large amount of foam during use, which brings many inconveniences to the use site. At the same time, as organic small molecules, quaternary ammonium salt bactericides also have the disadvantages of easy volatilization, poor chemical stability, high toxicity and strong irritation. Studies have shown that cationic oxygen-containing polyquaternary ammonium salt bactericides with antibacterial groups can overcome the above-mentioned shortcomings and have better antibacterial performance than small molecule antibacterial agents. Therefore, the synthesis and application of organic high molecular oxygen-containing polyquaternary ammonium salt bactericides have become one of the important topics in the research and development of bactericides. In the research of "Synthesis and Performance of New Polyquaternary Ammonium Salt" by Wang Ping of Nanjing University of Technology, two types of organic cationic polyquaternary ammonium salts were synthesized, i.e. oxygen-containing ethyl quaternary ammonium salt polymer synthesized from dichloroether and tetramethyl ethylenediamine, and alkyl chain-containing polyquaternary ammonium salt synthesized from dichloro intermediate and tetramethyl ethylenediamine under certain conditions. Chinese patent CN103621502A discloses a kind of organic high molecular bactericide synthesized by using "one-step method" with tetramethyl ethylenediamine and dichloroether as main raw materials and 30% mass fraction of hydrogen peroxide as catalytic initiator, and the bactericidal rate of the bactericide to heterotrophic bacteria can reach more than 99%. Chinese patent CN108440254A introduces a new type of gemini surfactant 4-dodecyl phenol polyoxyethylene diether synthesized from 2,2'-dichloroether, 4-dodecyl phenol and cetyltrimethylammonium bromide as raw materials under alkaline conditions of sodium hydroxide solution, which breaks the pattern of using nonylphenol as raw material to synthesize long-chain gemini surfactant diether intermediate. Therefore, the synthesis of 2,2'-dichloroether, an important material for synthesizing oxygen-containing polyquaternary ammonium salt bactericides, has gradually attracted the attention of researchers.

[0003] 2,2'-dichloroether is a colorless transparent oily liquid, its properties are stable, used as fat, resin, ethyl fiber solvent, also used in organic synthesis and coating, is an important raw material for manufacturing fine chemicals. There are two kinds of existing synthesis methods, one is from chloroethanol by catalyst intermolecular dehydration and preparation, this method due to the higher price of raw materials is rarely applied to production, in recent years, with the rapid development of China's ethylene glycol industry, diethylene glycol (diethylene glycol) as the important raw material of petroleum chemical industry, the annual output of ethylene glycol byproduct can reach about 400000 tons, its direct use market capacity is limited, therefore, to speed up the development of diethylene glycol high value added downstream products, expand the use of diethylene glycol, make full use of diethylene glycol resources, improve its economic benefit, is an important task. Another is to react with diethylene glycol and thionyl chloride to prepare, zheng Zhongchuan et al. In the article "use of chloroethanol byproduct liquid preparation of 2,2'-dichloroether" introduced by thionyl chloride and chloroethanol byproduct liquid containing chloro diethylene glycol in the presence of catalyst N,N-dimethylformamide (DMF) under the action of synthesis preparation of 2,2`-dichloroether, the yield is 85% (among them: with pyridine as catalyst is the yield of 72%, with triethylamine as catalyst is the yield of 78%), and the control of reaction temperature, the selection and amount of catalyst, the influence factors such as the feeding ratio of substances are discussed. The synthesis process of intermediate dichloroether is involved in Chinese patent CN108440254A, specifically, 1.1 mol of thionyl chloride is slowly added in a reaction vessel containing 0.5 mol of diethylene glycol under stirring conditions, 20 min of dropwise addition is completed, heating reflux reaction is carried out for 3-4 h until no gas is emitted from the system, excess thionyl chloride is distilled out at normal pressure, then transparent liquid dichloroether is collected by vacuum distillation at 70-72℃ / 5mmHg, the yield is 86% based on the mole number of diethylene glycol. The method generally requires excess thionyl chloride, and a large amount of sulfur dioxide and hydrogen chloride gas is generated during the synthesis process, and the heat released during the reaction process will cause a large loss of thionyl chloride, which not only wastes raw materials and reduces the yield, but also increases the discharge amount of waste; at the same time, thionyl chloride is a smoking liquid, and it decomposes when it comes into contact with water, in order to obtain better yield and protect the environment, the water content in the raw materials and the airtightness of the reaction system must be strictly controlled. SUMMARY

[0004] In view of the technical problems of existing 2,2'-dichloroether synthesis method, such as strict process conditions, high raw material cost, large waste discharge amount of sulfur dioxide, and low yield, the present application provides a 2,2'-dichloroether synthesis method with low cost and simple synthesis method.

[0005] A preparation method of 2,2'-dichloroether, specifically comprising the following steps:

[0006] Under the condition of 70-80℃ and stirring, hydrogen chloride gas is introduced into the reaction kettle containing diethylene glycol and catalyst within a certain time;

[0007] After the hydrogen chloride gas is passed in, continue to warm to 95-98℃ and keep the reaction for 3-5 hours;

[0008] Cooling distillation to obtain 2,2'-dichloroether;

[0009] The catalyst is a composite catalyst system composed of organic carboxylic acid and Lewis acid.

[0010] The catalyst is 1-5% of the amount of diethylene glycol.

[0011] The organic carboxylic acid in the composite catalyst system can be any one of glacial acetic acid and n-butyric acid, and the Lewis acid can be any one of aluminum chloride and zinc chloride.

[0012] The mass ratio of the organic carboxylic acid to the Lewis acid in the composite catalyst system is 1:1-3.

[0013] The hydrogen chloride gas is passed in for 2-8 hours in step (2).

[0014] The total amount of hydrogen chloride gas and the molar ratio of diethylene glycol are 2.0-2.8:1.

[0015] The distillation in step (3) is carried out at 68-70℃ and 1.1-1.5KPa to obtain 2,2'-dichloroether.

[0016] Before step (3), cool to 50±2℃, and distill under negative pressure of -0.003~-0.002MPa to remove excess hydrogen chloride gas and perform tail gas absorption.

[0017] Diethylene glycol is used as a reaction raw material, and a step-by-step nucleophilic double substitution chlorination reaction is carried out between diethylene glycol and hydrogen chloride gas under the catalysis of a composite system composed of organic carboxylic acid and Lewis acid to prepare 2,2'-dichloroether.

[0018] Under traditional conditions, the conditions for breaking the ether bond are to use strong acids such as hydrogen halide acid. Under acidic conditions, the ether bond forms a salt, and the halogen group further attacks the nucleophilic group. For primary and secondary carbons, it is a Sn2 substitution reaction, and the reaction speed is related to the nucleophilic degree of the nucleophilic group. - Br - Cl - .

[0019] Therefore, the traditional method for preparing 2,2'-dichloroether uses dichloro sulfoxide as a chlorine substitution agent, and directly uses hydrogen chloride. On the one hand, the reaction speed is slow; on the other hand, both the hydroxyl group and the ether bond will form a salt. Under the same reaction conditions, both are Sn2 reactions, and the hydroxyl group undergoes a substitution reaction, and the ether bond will break.

[0020] And the present application uses Lewis acid (for example, aluminum chloride), on the one hand, forms [AlCl4] - This kind of strong nucleophilic but large group volume anion group, acid condition ether bond and hydroxyl form salt, but because [AlCl4] - The space volume is large, and the space resistance effect is obvious, and the Sn2 reaction at the ether bond is not easy to occur, and the hydroxyl carbon is primary carbon, and the space resistance effect is very small, and the normal reaction can be realized.

[0021] However, only using Lewis acid, more one-chloro substitution products are produced, and the yield of 2,2'-dichloroether is not high, and the organic carboxylic acid has enough acidity because of hydrogen chloride, so the action of the organic carboxylic acid is not only to provide acid conditions, and adding other inorganic acids still produces one-chloro substitution products, and adding macromolecular carboxylic acid does not react. This is a specific experimental phenomenon, and the specific mechanism is still unknown.

[0022] Moreover, the cost is also too high by only adding Lewis acid.

[0023] Beneficial effects:

[0024] (1) Diethylene glycol is used as a reaction raw material, nucleophilic double substitution chlorination reaction with hydrogen chloride gas occurs under the action of a catalyst, a new method for synthesizing 2,2'-dichloroether is provided, and meanwhile, the resource utilization of industrial by-product diethylene glycol can be realized;

[0025] (2) The use of organic carboxylic acid and Lewis acid composite catalyst has high catalytic selectivity, effectively inhibits the rupture of the ether bond in the system, and improves the product yield;

[0026] (3) The synthesis method has the advantages of easy raw material, low cost, simple process, easy control, small environmental pollution, and easy industrial production. DETAILED DESCRIPTION

[0027] In order to further explain the significance of the present application, the contents involved in the present application will be described below in combination with examples, but the contents are not limited.

[0028] Example 1

[0029] (1) Diethylene glycol 212 g and catalyst 6.36 g (of which: glacial acetic acid 2.12 g, zinc chloride 4.24 g) are added into a four-port glass reaction kettle with an electric stirrer, a thermometer, a gas inlet pipe and a reflux condenser, stirring is started and heating is started to heat to 75±2℃, hydrogen chloride gas is continuously introduced for 4 hours, and the molar ratio of hydrogen chloride gas to diethylene glycol is 2.2:1;

[0030] (2) After the hydrogen chloride gas is introduced, the system is continuously heated to 95-98℃ and kept for 3 hours;

[0031] (3) After the end of the heat preservation, cool down to 50±2℃, remove the excess hydrogen chloride gas under the condition of -0.003~-0.002MPa pressure and carry out tail gas absorption;

[0032] (4) Maintain the vacuum degree of the system at about 1.2KPa (about 9mmHg), carry out vacuum distillation, and collect the 68~70℃ fraction at the top of the distillation column to obtain 2,2'-dichloroether product 261.63g.

[0033] The gas chromatograph GC detection characterization: 2,2'-dichloroether gas chromatograph purity is 98.83%, the amount of product yield is 90.41% based on the input diethylene glycol.

[0034] Example 2

[0035] (1) In the four-port glass reaction kettle with electric stirrer, thermometer, gas inlet pipe and reflux condenser, add diethylene glycol 212g and catalyst 6.36g (of which: n-butyric acid 2.12g, zinc chloride 4.24g), start stirring and heat to 75±2℃, according to the continuous hydrogen chloride gas for 5 hours, the molar ratio of hydrogen chloride gas to diethylene glycol is 2.4:1;

[0036] (2) After the end of hydrogen chloride gas, continue to heat the system to 95~98℃ for 4 hours;

[0037] (3) After the end of the heat preservation, cool down to 50±2℃, remove the excess hydrogen chloride gas under the condition of -0.003~-0.002MPa pressure and carry out tail gas absorption;

[0038] (4) Maintain the vacuum degree of the system at about 1.4KPa (about 11mmHg), carry out vacuum distillation, and collect the 68~70℃ fraction at the top of the distillation column to obtain 2,2'-dichloroether product 261.95g.

[0039] The gas chromatograph GC detection characterization: 2,2'-dichloroether gas chromatograph purity is 98.34%, the amount of product yield is 90.07% based on the input diethylene glycol.

[0040] Example 3

[0041] (1) In the four-port glass reaction kettle with electric stirrer, thermometer, gas inlet pipe and reflux condenser, add diethylene glycol 212g and catalyst 8.48g (of which: glacial acetic acid 2.83g, 5.65 aluminum chloride g), start stirring and heat to 75±2℃, according to the continuous hydrogen chloride gas for 5 hours, the molar ratio of hydrogen chloride gas to diethylene glycol is 2.4:1;

[0042] (2) After the hydrogen chloride gas is finished, the system continues to be heated to 95-98°C and is kept for 5 hours;

[0043] (3) After the keeping, the temperature is decreased to 50±2°C, and the excess hydrogen chloride gas is removed by distillation under the conditions of -0.003 to -0.002 MPa pressure and tail gas absorption is performed;

[0044] (4) The vacuum degree of the system is maintained at about 1.4 KPa (about 11 mmHg), and vacuum distillation is performed, and 2,2'-dichloroether product 258.63 g is collected at 68-70°C at the top of the distillation column.

[0045] The 2,2'-dichloroether gas chromatography purity is 98.34% by gas chromatograph GC detection characterization, and the product yield is 88.93% based on the amount of diethylene glycol input.

[0046] Example 4

[0047] (1) In a four-port glass reaction kettle with an electric stirrer, a thermometer, a gas inlet pipe and a reflux condenser, diethylene glycol 212 g and catalyst 8.48 g (of which: n-butyric acid 2.83 g, 5.65 aluminum chloride g) are added, the stirring is started and heated to 75±2°C, and then hydrogen chloride gas is continuously introduced for 4 hours, and the molar ratio of hydrogen chloride gas to diethylene glycol is 2.3:1;

[0048] (2) After the hydrogen chloride gas is finished, the system continues to be heated to 95-98°C and is kept for 5 hours;

[0049] (3) After the keeping, the temperature is decreased to 50±2°C, and the excess hydrogen chloride gas is removed by distillation under the conditions of -0.003 to -0.002 MPa pressure and tail gas absorption is performed;

[0050] (4) The vacuum degree of the system is maintained at about 1.1 KPa (about 11 mmHg), and vacuum distillation is performed, and 2,2'-dichloroether product 252.59 g is collected at 68-70°C at the top of the distillation column.

[0051] The 2,2'-dichloroether gas chromatography purity is 98.27% by gas chromatograph GC detection characterization, and the product yield is 86.79% based on the amount of diethylene glycol input.

[0052] Example 5

[0053] (1) In the four-port glass reactor with electric stirrer, thermometer, gas inlet tube and reflux condenser, add diethylene glycol 318 g and catalyst 3.18 g (of which: glacial acetic acid 1.59 g, zinc chloride 1.59 g), start stirring and heat to 78±2℃, then continuously pass hydrogen chloride gas for 3 hours (molar ratio of hydrogen chloride gas to diethylene glycol is 2.0:1);

[0054] (2) Continue to heat the reaction to 98℃ and keep for 5 hours;

[0055] (3) After the incubation, cool to 50±2℃, distill excess hydrogen chloride gas under negative pressure of -0.005 MPa and perform tail gas absorption;

[0056] (4) Maintain the vacuum degree of the system at about 1.1 KPa (about 9 mmHg) and perform vacuum distillation. Collect the 68~70℃ fraction at the top of the distillation column to obtain 2,2'-dichloroether product 247.63 g.

[0057] The gas chromatograph GC detection characterization shows that the gas chromatograph purity of 2,2'-dichloroether is 98.99%, and the product yield is 85.71% based on the amount of diethylene glycol input.

[0058] Comparative Example 1

[0059] In the four-port glass reactor with electric stirrer, thermometer, gas inlet tube and reflux condenser, add diethylene glycol 106 g and anhydrous aluminum chloride 10.6 g, and other operations and process conditions are the same as in Example 3. After vacuum distillation separation, 2,2'-dichloroether product 98.80 g is obtained.

[0060] The gas chromatograph GC detection characterization shows that the gas chromatograph purity of 2,2'-dichloroether is 97.38%, and the product yield is 67.28% based on the amount of diethylene glycol input.

[0061] Comparative Example (Reference: Zheng Zhongchuan et al. Preparation of 2,2'-dichloroether from by-product liquid of chloroethanol production)

[0062] In a four-necked flask with electric stirring, add catalyst N, N-dimethylformamide and 720 mL of chloroethanol by-product liquid, start stirring, then slowly drop 600 mL of thionyl chloride at room temperature. After the drop is completed, slowly heat in water bath, control the gas discharge speed, the water bath heating temperature finally reaches about 95℃, until no gas is discharged, the reaction time is about 3.5 hours. After the synthesis reaction is completed, neutralize with dilute alkali, wash with water until neutral, then perform vacuum distillation, maintain the vacuum degree at about 10 mmHg during vacuum distillation, the column bottom temperature reaches about 100℃, the column top temperature reaches about 65℃, take samples, analyze the purity by gas chromatograph, when the purity reaches more than 98%, collect the finished product 2,2'-dichloroether, when the column bottom temperature rises to about 160℃, stop collecting, the distillation is completed, the product yield is calculated to be 85%.

Claims

1. A method for preparing 2,2'-dichloroethyl ether, characterized in that: The specific steps include: (1) At 70-80°C and under stirring conditions, hydrogen chloride gas is introduced into a reactor containing diethylene glycol and a catalyst for a certain period of time; (2) After the hydrogen chloride gas is introduced, the temperature is continued to rise to 95-98°C and kept warm for 3-5 hours; (3) Distillation at reduced temperature to obtain 2,2'-dichloroethyl ether; The catalyst is a composite catalytic system composed of organic carboxylic acid and Lewis acid; The organic carboxylic acid in the composite catalyst system is any one of glacial acetic acid and n-butyric acid, the Lewis acid is any one of aluminum chloride and zinc chloride, and the mass ratio of the organic carboxylic acid to the Lewis acid is 1:1 to 3; The molar ratio of the total amount of hydrogen chloride gas to diethylene glycol is 2.0 to 2.8:

1.

2. The preparation method according to claim 1, characterized in that The amount of catalyst used is 1~5% of the amount of diethylene glycol used.

3. The preparation method according to claim 1, characterized in that The time for introducing hydrogen chloride gas in step (2) is 2 to 8 hours.

4. The preparation method according to claim 1, characterized in that The step (3) is carried out at 68 ~ 70℃, 1.1 ~ At 1.5KPa, 2,2'-dichloroethyl ether was obtained by distillation.

5. The preparation method according to claim 1, characterized in that Before step (3), the temperature is lowered to 50±2°C, and excess hydrogen chloride gas is distilled off under a negative pressure of -0.003~-0.002MPa and tail gas absorption is performed.