Preparation method of alkyl glycol monoalkyl ether

Abstract

The invention relates to a preparation method of alkyl glycol monoalkyl ether, which comprises the following steps: (1) by taking fatty alcohol as a raw material, controlling the temperature at-20 DEG C to 20 DEG C in an alkaline environment, and directly reacting with sulfonyl chloride without adding a catalyst to prepare fatty alcohol sulfonate; and (2) reacting the product fatty alcohol sulfonate obtained in the step (1) with alkyl glycol under the condition of alkali metal alkoxide at the temperature of 80-150 DEG C to obtain the corresponding alkyl glycol monoalkyl ether. The raw materials are cheap and easy to obtain, the reaction conditions are mild, the conversion rate and selectivity are high, the product purity can reach 99%, and the method has high economic and social value in popularization.

Description

Technical Field

[0001] The invention belongs to the field of chemical synthesis and relates to a method for synthesizing alkyl glycol monoalkyl ether. Background Art

[0002] Alkyl glycol monoalkyl ether, the structural formula of which is shown in formula (I):

[0003] Formula I:

[0004] It is a very important organic compound in the chemical industry and is widely used in various fields. Because its molecular structure contains both lipophilic groups and hydrophilic groups, it is an important component of surfactants. It is commonly used as a dispersant, lubricant and cleaning agent in industries such as textiles, plastics, rubber and metal processing. At the same time, it is reported to be used as a leveling agent in silicon-containing transparent wear-resistant coatings (CN103694888A), by adjusting the surface tension of the coating, improving the wettability and leveling of the coating, and reducing the defects that appear on the surface of the coating. Some compounds have insect pheromone functions, among which 2-undecyloxy-1-ethanol is the aggregation pheromone of Monochamus alternatus. At the same time, it can be used as an important chemical raw material intermediate, and more complex compounds can be further synthesized, and it can also be used to prepare flexible polyurethane foams and synthetic resins.

[0005] Currently, the method reported to synthesize alkyl glycol monoalkyl ethers is mainly the Williamson method, but this method generally requires a catalyst and has high costs or high risks in the operation process.

[0006] The main routes are as follows:

[0007] 1. Using 1-bromodecane and ethylene glycol as raw materials, 2-undecyloxy-1-ethanol is synthesized under certain conditions. The chemical formula of the synthesis method is as follows:

[0008]

[0009] This route requires the addition of sodium hydroxide, potassium hydroxide (CN113563162A); metallic sodium [Sci.Rep.2016,6,29300; Dyes and Pigments 2013,96,16-24]; sodium hydride [J.Chem.Ecol.2010,36,570-583] to provide an alkaline environment, and then the temperature is raised to react, and finally 2-undecyloxy-1-ethanol is prepared.

[0010] The disadvantages of this route are: the use of bromoalkane as a raw material is costly, and will cause pollution and waste of bromine, which is unfavorable to the environment and cost control. At the same time, the yield of this route is not high.

[0011] 2. Take alkyl alcohol and sulfonyl chloride as raw materials, add some suitable base to prepare fatty alcohol sulfonate. Then remove the solvent by conventional method, add excess ethylene glycol and phase transfer catalyst to prepare the product 2-alkoxy-1-ethanol (CN113292401A). The chemical formula of the synthesis method is as follows:

[0012]

[0013] The disadvantages of this route are: in the reaction of synthesizing fatty alcohol sulfonate, the added organic base will produce organic salt, which cannot be recovered in the subsequent reaction treatment, resulting in increased costs and environmental pollution; at the same time, the base used in the first step will produce water in the second step, and the presence of water will hydrolyze the fatty alcohol sulfonate to produce alkyl alcohol as a by-product. The chemical formula of the side reaction is as follows:

[0014]

[0015] R'OSO2R+H2O→R'OH

[0016] The by-product alkyl alcohol produced will affect the purity and yield and increase the cost.

[0017] 3. Undecyl alcohol and 2-tert-butoxyethyl chloride are used as raw materials to react and prepare 1-(2-tert-butoxyethoxy)-undecane, which is then hydrolyzed under acidic conditions to obtain the product 2-undecyloxy-1-ethanol (CN107805187A). The chemical formula of the synthesis method is as follows:

[0018]

[0019] The disadvantages of this route are: the base used still includes metallic sodium, sodium hydrogen, etc., which are less safe; at the same time, the raw material 2-tert-butoxyethyl chloride is relatively expensive; and a special deprotection step is required, which requires a large amount of high-concentration strong acid, and there are many by-products, which is not conducive to large-scale industrial production. Summary of the invention

[0020] In view of the above technical status, the present invention provides a method for preparing alkyl glycol monoalkyl ether which is safe and reliable, generates less waste, has low cost, and has high yield and selectivity.

[0021] The technical solution of the present invention is as follows:

[0022] A method for preparing an alkyl glycol monoalkyl ether, wherein the alkyl glycol monoalkyl ether has a structure shown in formula (I):

[0023] Formula I: n is 4 to 15, n' is 2 to 4;

[0024] The steps include:

[0025] (1) Using fatty alcohol as raw material, reacting with sulfonyl halide under alkaline conditions to prepare fatty alcohol sulfonate;

[0026] (2) Fatty alcohol sulfonate is mixed with alkyl glycol, and reacted in the presence of an alkali metal alcohol salt to obtain alkyl glycol monoalkyl ether.

[0027] According to the present invention, preferably, the fatty alcohol sulfonate in step (1) has a structure shown in formula (II):

[0028] Formula II The sulfonyl halide has the following structure: R-SO2X;

[0029] In the structure of fatty alcohol sulfonate and sulfonyl halide, n is 4-15, R is selected from C1-C8 alkyl, phenyl, p-methylphenyl, p-nitrophenyl, o-nitrophenyl; X is selected from F, Cl, Br, I.

[0030] The fatty alcohol has a structure shown in formula (III):

[0031] Formula III: n is 4 to 15.

[0032] According to the present invention, preferably, the reaction in step (1) is carried out in a solvent, and further preferably, the solvent is chloroform or dichloromethane;

[0033] Preferably, the alkaline condition is provided by an organic base; more preferably, the organic base is at least one of 1-methylimidazole, DBU, triethylamine, pyridine and DMAP.

[0034] According to the present invention, preferably, in step (1), the molar ratio of the fatty alcohol, the organic base and the sulfonyl halide is 1:(1.1-2.0):(1.1-1.5);

[0035] Preferably, the reaction temperature of step (1) is controlled at -20°C to 20°C, and the reaction time is 1h to 3h.

[0036] According to the present invention, preferably, the alkyl glycol described in step (2) has a structure shown in formula (IV):

[0037] Formula IV: n' is 2 to 4; further preferably, the alkyl glycol is 1,2-ethylene glycol, 1,3-propylene glycol or 1,4-butanediol;

[0038] Preferably, the alkali metal alkoxide is at least one of sodium methoxide, sodium ethoxide, potassium methoxide or potassium ethoxide.

[0039] According to the present invention, preferably, the molar ratio of fatty alcohol sulfonate to alkyl glycol in step (2) is 1:(10-20);

[0040] Preferably, the reaction temperature of step (2) is controlled at 80°C to 150°C, and the reaction time is 3h to 8h.

[0041] The beneficial effects of the present invention are as follows:

[0042] 1. The present invention eliminates the need for catalysts, simplifies the process, reduces costs, and is suitable for industrial-scale production.

[0043] 2. In step (2) of the present invention, alkali metal alkoxide is used to participate in the reaction, and theoretically no by-product fatty alcohol is produced, thereby improving the conversion rate and selectivity. The product purity can reach 99%, which has high economic and social value.

[0044] 3. In the present invention, during the post-reaction treatment in step (1), an inorganic strong base solution is added thereto to recover the organic base required for the reaction, thereby reducing pollution and improving the utilization rate of raw materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is the H NMR spectrum of ethylene glycol monoundecyl ether prepared in Example 1 of the present invention;

[0046] Figure 2 This is the H NMR spectrum of propylene glycol monoundecyl ether prepared in Example 3 of the present invention;

[0047] Figure 3 This is the H NMR spectrum of butanediol monoundecyl ether prepared in Example 5 of the present invention. DETAILED DESCRIPTION

[0048] The invention provides a method for preparing alkyl glycol monoalkyl ether which is safe and reliable, generates less waste, has low cost, and has high yield and selectivity.

[0049] A method for preparing an alkyl glycol monoalkyl ether, wherein the alkyl glycol monoalkyl ether has a structure shown in formula (I):

[0050] Formula I: n is 4 to 15, n' is 2 to 4;

[0051] The steps include:

[0052] (1) Using fatty alcohol as raw material, reacting with sulfonyl halide under alkaline conditions to prepare fatty alcohol sulfonate;

[0053] (2) Fatty alcohol sulfonate is mixed with alkyl glycol, and reacted in the presence of an alkali metal alcohol salt to obtain alkyl glycol monoalkyl ether.

[0054] In one or more preferred embodiments, the fatty alcohol sulfonate in step (1) has a structure shown in formula (II):

[0055] Formula II: The sulfonyl halide has the following structure: R-SO2X;

[0056] In the structure of fatty alcohol sulfonate and sulfonyl halide, n is 4-15, R is selected from C1-C8 alkyl, phenyl, p-methylphenyl, p-nitrophenyl, o-nitrophenyl; X is selected from F, Cl, Br, I.

[0057] The fatty alcohol has a structure shown in formula (III):

[0058] Formula III: n is 4 to 15.

[0059] In one or more preferred embodiments, the reaction in step (1) is carried out in a solvent, and further preferably, the solvent is chloroform or dichloromethane;

[0060] Preferably, the alkaline condition is provided by an organic base; more preferably, the organic base is at least one of 1-methylimidazole, DBU, triethylamine, pyridine and DMAP.

[0061] In one or more preferred embodiments, the molar ratio of fatty alcohol, organic base and sulfonyl halide in step (1) is 1: (1.1-2.0): (1.1-1.5);

[0062] Preferably, the reaction temperature of step (1) is controlled at -20°C to 20°C, and the reaction time is 1h to 3h.

[0063] According to the present invention, in one or more preferred embodiments, in step (1), a fatty alcohol, a solvent and an organic base are mixed, and then a mixture of sulfonyl chloride and a solvent is added dropwise, and a certain temperature is controlled and maintained for a period of time to obtain a reaction solution; water is added dropwise to the above reaction solution, and then separation, extraction, washing, and the organic phase is dried and concentrated to obtain a fatty alcohol sulfonate of formula (II);

[0064] An inorganic strong alkali aqueous solution is added to the aqueous phase after the above extraction to adjust the pH of the system to be alkaline, and then extraction and washing are performed, and the organic phase is dried and concentrated to obtain an organic base. The organic base can be recycled through a simple recovery process, which can further reduce the cost of the process.

[0065] According to the present invention, taking sulfonyl chloride as an example, the synthetic route of step (1) is as follows:

[0066]

[0067] Base·HCl+NaOH→Base+NaCl+H2O

[0068] According to the present invention, in one or more preferred embodiments, the alkyl glycol in step (2) has a structure shown in formula (IV):

[0069] Formula IV: n' is 2 to 4; further preferably, the alkyl glycol is 1,2-ethylene glycol, 1,3-propylene glycol or 1,4-butanediol;

[0070] Preferably, the alkali metal alkoxide is at least one of sodium methoxide, sodium ethoxide, potassium methoxide or potassium ethoxide.

[0071] In one or more preferred embodiments, the molar ratio of fatty alcohol sulfonate to alkyl glycol in step (2) is 1:(10-20);

[0072] Preferably, the reaction temperature of step (2) is controlled at 80°C to 150°C, and the reaction time is 3h to 8h.

[0073] According to the present invention, in one or more preferred embodiments, in step (2), the alkyl glycol (IV) is mixed with an alkali metal alkoxide, stirred and heated, and then distilled under reduced pressure at a certain temperature for a certain time. Then, the fatty alcohol sulfonate (II) is added, and the temperature is controlled to be maintained for a period of time to obtain a reaction solution;

[0074] Water is added dropwise to the above reaction solution, followed by separation, extraction and washing. The organic phase is dried and concentrated to obtain alkyl glycol monoalkyl ether of formula (I).

[0075] According to the present invention, the synthetic route of step (2) is as follows:

[0076]

[0077] In step (2) of the present invention, alkali metal alkoxide is used to participate in the reaction, and theoretically no by-product fatty alcohol is produced, thereby improving the conversion rate and selectivity.

[0078] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with specific implementation methods.

[0079] Example 1

[0080] The preparation method of ethylene glycol monoundecyl ether comprises the following steps:

[0081] (1) Add 172g (1mol, 1eq) of undecanol and 800ml of dichloromethane to a 2L reaction bottle, start stirring, then add 162g (1.6mol, 1.6eq) of triethylamine, and cool to 0°C in an ice-water bath. Then slowly add a mixture of 149g (1.3mol, 1.3eq) of methanesulfonyl chloride and 100ml of dichloromethane, and control the system temperature to 0°C for 2h. Then add 300g of water to the reaction system to quench the reaction, and extract and separate the phases. The organic phase is dried with anhydrous sodium sulfate and concentrated under reduced pressure; 300ml of dichloromethane and an inorganic strong base sodium hydroxide aqueous solution are added to the aqueous phase, and the phases are extracted and separated. The organic phase is dried and distilled under reduced pressure to recover 144g of triethylamine (89% recovery rate).

[0082] (2) Add 620g (10mol, 10eq) of 1,2-ethylene glycol to a 2L reaction bottle and stir, then add 64.8g (1.2mol, 1.2eq) of sodium methoxide, heat to 40°C, and evacuate for 30min. Then add the organic phase in step (1), heat to 100°C, and continue to maintain for 5h before the reaction is completed. After cooling, add 400g of water dropwise to the system, add an appropriate amount of hydrochloric acid to the mixture to adjust the pH to 7, and separate the organic phase. Extract the aqueous phase twice with 300ml of EA, combine the organic phases, dry with sodium sulfate, and concentrate to obtain the crude product. Reduced pressure distillation gave 198g of the product ethylene glycol monoundecyl ether, with a yield of 92% and a purity of 99.4%.

[0083] The H NMR spectrum of ethylene glycol monoundecyl ether prepared in this example is as follows: Figure 1 shown.

[0084] Example 2

[0085] The preparation method of ethylene glycol monohexyl ether comprises the following steps:

[0086] (1) Add 102g (1mol, 1eq) of n-hexanol and 700ml of dichloromethane to a 2L reaction bottle, start stirring, then add 141g (1.4mol, 1.4eq) of triethylamine, and cool to 0°C in an ice-water bath. Then slowly add a mixture of 126g (1.1mol, 1.1eq) of methanesulfonyl chloride and 100ml of dichloromethane, and control the system temperature to 0°C for 1h. Then add 300g of water to the reaction system to quench the reaction, and extract and separate the phases. The organic phase is dried with anhydrous sodium sulfate and concentrated under reduced pressure; 300ml of dichloromethane and an inorganic strong base sodium hydroxide aqueous solution are added to the aqueous phase, and the phases are extracted and separated. The organic phase is dried and distilled under reduced pressure to recover 130g of triethylamine (92% recovery rate).

[0087] (2) Add 620g (10mol, 10eq) of 1,2-ethylene glycol to a 2L reaction bottle and stir, then add 64.8g (1.2mol, 1.2eq) of sodium methoxide, heat to 40°C, and evacuate for 30min. Then add the organic phase in step (1), heat to 90°C, and continue to maintain for 5h before the reaction is completed. After cooling, add 400g of water dropwise to the system, add an appropriate amount of hydrochloric acid to the mixture to adjust the pH to 7, and separate the organic phase. Extract the aqueous phase twice with 300ml of EA, combine the organic phases, dry, and concentrate under reduced pressure to obtain the crude product. Distill under reduced pressure to obtain 136g of the product ethylene glycol monohexyl ether, with a yield of 93% and a purity of 99.5%.

[0088] Example 3

[0089] The preparation method of propylene glycol monoundecyl ether comprises the following steps:

[0090] (1) Add 172g (1mol, 1eq) of undecanol and 800ml of dichloromethane to a 2L reaction bottle, start stirring, then add 162g (1.6mol, 1.6eq) of triethylamine, and cool to 0°C in an ice-water bath. Then slowly add a mixture of 149g (1.3mol, 1.3eq) of methanesulfonyl chloride and 100ml of dichloromethane, and control the system temperature to 0°C for 2h. Then add 300g of water to the reaction system to quench the reaction, and extract and separate the phases. The organic phase is dried with anhydrous sodium sulfate and concentrated under reduced pressure; 300ml of dichloromethane and an inorganic strong base sodium hydroxide aqueous solution are added to the aqueous phase, and the phases are extracted and separated. The organic phase is dried and distilled under reduced pressure to recover 144g of triethylamine (89% recovery rate).

[0091] (2) Add 990g (13mol, 13eq) 1,3-propylene glycol to a 2L reaction bottle and stir, then add 64.8g (1.2mol, 1.2eq) sodium methoxide, heat to 45°C, and evacuate for 30min. Then add the organic phase in step (1), heat to 110°C, and continue to maintain for 5h before the reaction is completed. After cooling, add 400g water dropwise to the system, add an appropriate amount of hydrochloric acid to the mixture to adjust the pH to 7, and separate the organic phase. Extract the aqueous phase twice with 300ml of EA, combine the organic phases, dry with sodium sulfate, and concentrate to obtain the crude product. Reduced pressure distillation gives 207g of the product propylene glycol monoundecyl ether, with a yield of 90% and a purity of 99.1%.

[0092] The H NMR spectrum of propylene glycol monoundecyl ether prepared in this example is as follows: Figure 2 shown.

[0093] Example 4

[0094] The preparation method of propylene glycol monohexyl ether comprises the following steps:

[0095] (1) Add 102g (1mol, 1eq) of n-hexanol and 700ml of dichloromethane to a 2L reaction bottle, start stirring, then add 141g (1.4mol, 1.4eq) of triethylamine, and cool to 0°C in an ice-water bath. Then slowly add a mixture of 126g (1.1mol, 1.1eq) of methanesulfonyl chloride and 100ml of dichloromethane, and control the system temperature to 0°C for 1h. Then add 300g of water to the reaction system to quench the reaction, and extract and separate the phases. The organic phase is dried with anhydrous sodium sulfate and concentrated under reduced pressure; 300ml of dichloromethane and an inorganic strong base sodium hydroxide aqueous solution are added to the aqueous phase, and the phases are extracted and separated. The organic phase is dried and distilled under reduced pressure to recover 130g of triethylamine (92% recovery rate).

[0096] (2) Add 836g (11mol, 11eq) of 1,3-propylene glycol to a 2L reaction bottle and stir, then add 64.8g (1.2mol, 1.2eq) of sodium methoxide, heat to 45°C, and evacuate for 30min. Then add the organic phase in step (1), heat to 100°C, and continue to maintain for 5h before the reaction is completed. After cooling, add 400g of water dropwise to the system, add an appropriate amount of hydrochloric acid to the mixture to adjust the pH to 7, and separate the organic phase. Extract the aqueous phase twice with 300ml of EA, combine the organic phases, dry with sodium sulfate, and concentrate to obtain the crude product. Distill under reduced pressure to obtain 146g of the product propylene glycol monohexyl ether, with a yield of 91% and a purity of 99.2%.

[0097] Example 5

[0098] The preparation method of butanediol monoundecyl ether comprises the following steps:

[0099] (1) Add 172g (1mol, 1eq) of undecanol and 800ml of dichloromethane to a 2L reaction bottle, start stirring, then add 162g (1.6mol, 1.6eq) of triethylamine, and cool to 0°C in an ice-water bath. Then slowly add a mixture of 153g (1.3mol, 1.3eq) of methanesulfonyl chloride and 100ml of dichloromethane, and control the system temperature to 0°C for 2h. Then add 300g of water to the reaction system to quench the reaction, and extract and separate the phases. The organic phase is dried with anhydrous sodium sulfate and concentrated under reduced pressure; 300ml of dichloromethane and an inorganic strong base sodium hydroxide aqueous solution are added to the aqueous phase, and the phases are extracted and separated. The organic phase is dried and distilled under reduced pressure to recover 144g of triethylamine (89% recovery rate).

[0100] (2) Add 1350g (15mol, 15eq) 1,4-butanediol to a 2L reaction bottle and stir, then add 64.8g (1.2mol, 1.2eq) sodium methoxide, heat to 50°C, and evacuate for 30min. Then add the organic phase in step (1), heat to 115°C, and continue to maintain for 5h before the reaction is completed. After cooling, add 400g water dropwise to the system, add an appropriate amount of hydrochloric acid to the mixture to adjust the pH to 7, and separate the organic phase. Extract the aqueous phase twice with 300ml of EA, combine the organic phases, dry with sodium sulfate, and concentrate to obtain the crude product. Distill under reduced pressure to obtain 212g of the product butanediol monoundecyl ether, with a yield of 87% and a purity of 99.3%.

[0101] The NMR hydrogen spectrum of butanediol monoundecyl ether prepared in this example is as follows: Figure 3 shown.

[0102] Example 6

[0103] The preparation method of butanediol monohexyl ether comprises the following steps:

[0104] (1) Add 102g (1mol, 1eq) of n-hexanol and 700ml of dichloromethane to a 2L reaction bottle, start stirring, then add 141g (1.4mol, 1.4eq) of triethylamine, and cool to 0°C in an ice-water bath. Then slowly add a mixture of 126g (1.1mol, 1.1eq) of methanesulfonyl chloride and 100ml of dichloromethane, and control the system temperature to 0°C for 1h. Then add 300g of water to the reaction system to quench the reaction, and extract and separate the phases. The organic phase is dried with anhydrous sodium sulfate and concentrated under reduced pressure; 300ml of dichloromethane and an inorganic strong base sodium hydroxide aqueous solution are added to the aqueous phase, and the phases are extracted and separated. The organic phase is dried and distilled under reduced pressure to recover 130g of triethylamine (92% recovery rate).

[0105] (2) Add 1260g (14mol, 14eq) 1,4-butanediol to a 2L reaction bottle and stir, then add 64.8g (1.2mol, 1.2eq) sodium methoxide, heat to 50°C, and evacuate for 30min. Then add the organic phase in step (1), heat to 105°C, and continue to maintain for 5h before the reaction is completed. After cooling, add 400g water dropwise to the system, add an appropriate amount of hydrochloric acid to the mixture to adjust the pH to 7, and separate the organic phase. Extract the aqueous phase twice with 300ml of EA, combine the organic phases, dry with sodium sulfate, and concentrate to obtain the crude product. Distill under reduced pressure to obtain 157g of the product butanediol monohexyl ether, with a yield of 90% and a purity of 99.4%.

[0106] The above description is only the preferred embodiment of the present invention, and does not limit the patent scope of the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention and directly or indirectly applied to other related technical fields shall be included in the protection scope of the present invention.

Claims

1. A method for preparing an alkyl glycol monoalkyl ether, wherein the alkyl glycol monoalkyl ether has a structure shown in formula (I): Formula I: n is 4 to 15, n' is 2 to 4; The steps include: (1) Using fatty alcohol as raw material, reacting with sulfonyl halide under alkaline conditions to prepare fatty alcohol sulfonate; (2) Fatty alcohol sulfonate is mixed with alkyl glycol, and reacted in the presence of an alkali metal alcohol salt to obtain alkyl glycol monoalkyl ether.

2. The method for preparing alkyl glycol monoalkyl ether according to claim 1, characterized in that: The fatty alcohol sulfonate described in step (1) has a structure shown in formula (II): Formula II: The structure of the sulfonyl halide is R-SO2X, and the fatty alcohol has a structure shown in formula (III): Formula III: In the structure of fatty alcohol sulfonate, sulfonyl halide and fatty alcohol, n is 4-15, R is selected from C1-C8 alkyl, phenyl, p-methylphenyl, p-nitrophenyl and o-nitrophenyl; X is selected from Cl, Br and I.

3. The method for preparing alkyl glycol monoalkyl ether according to claim 1, characterized in that: The reaction in step (1) is carried out in a solvent; preferably, the solvent is chloroform or dichloromethane.

4. The method for preparing alkyl glycol monoalkyl ether according to claim 1, characterized in that: In step (1), an organic base is used to provide alkaline conditions; preferably, the organic base is at least one of 1-methylimidazole, DBU, triethylamine, pyridine, and DMAP.

5. The method for preparing alkyl glycol monoalkyl ether according to claim 4, characterized in that: In step (1), the molar ratio of fatty alcohol, organic base and sulfonyl halide is 1:(1.1-2.0):(1.1-1.5).

6. The method for preparing alkyl glycol monoalkyl ether according to claim 1, characterized in that: The reaction temperature of step (1) is controlled at -20°C to 20°C.

7. The method for preparing alkyl glycol monoalkyl ether according to claim 1, characterized in that: The alkyl glycol described in step (2) has a structure shown in formula (IV): Formula IV: n' is 2 to 4; Preferably, the alkyl diol is 1,2-ethylene glycol, 1,3-propylene glycol or 1,4-butanediol.

8. The method for preparing alkyl glycol monoalkyl ether according to claim 1, characterized in that: The alkali metal alkoxide described in step (2) is at least one of sodium methoxide, sodium ethoxide, potassium methoxide or potassium ethoxide.

9. The method for preparing alkyl glycol monoalkyl ether according to claim 1, characterized in that: In step (2), the molar ratio of fatty alcohol sulfonate to alkyl glycol is 1:(10-20).

10. The method for preparing alkyl glycol monoalkyl ether according to claim 1, characterized in that: The reaction temperature of step (2) is controlled at 80°C to 150°C.

Images