阅读说明：本技术 一种碱性离子液体中合成乙二醇单叔丁醚的方法 (Method for synthesizing ethylene glycol mono-tert-butyl ether in alkaline ionic liquid ) 是由 周玉文 于 2019-10-23 设计创作，主要内容包括：本发明涉及一种碱性离子液体中合成乙二醇单叔丁醚的方法,经过选用碱性离子液体作为催化剂和溶剂催化叔丁醇与环氧乙烷反应制备乙二醇单叔丁基,提供了一种适应于工业化生产的碱性离子液体中合成乙二醇单叔丁醚的方法,该制备方法收率大于93％,纯度大于99％,且工艺简单、适合工业化生产的要求。(The invention relates to a method for synthesizing ethylene glycol mono-tert-butyl ether in alkaline ionic liquid, which is used for preparing the ethylene glycol mono-tert-butyl ether by catalyzing tert-butyl alcohol to react with ethylene oxide by using the alkaline ionic liquid as a catalyst and a solvent, and provides a method for synthesizing the ethylene glycol mono-tert-butyl ether in the alkaline ionic liquid, which is suitable for industrial production, wherein the yield of the preparation method is more than 93 percent, the purity of the preparation method is more than 99 percent, and the process is simple and is suitable for the requirements of industrial production.)

1. A method for synthesizing ethylene glycol mono-tert-butyl ether in alkaline ionic liquid adopts tert-butyl alcohol and ethylene oxide as reaction raw materials, and takes the alkaline ionic liquid as a catalyst and a solvent, and the specific preparation method is as follows:

adding tert-butyl alcohol into alkaline ionic liquid, stirring uniformly, heating to 30-50 ℃, slowly dropwise adding a tetrahydrofuran solution of ethylene oxide, after dropwise adding, keeping the temperature for reaction for a period of time, after the reaction is finished, standing and layering to obtain an organic phase layer and an ionic liquid layer, and distilling the organic layer under reduced pressure to obtain high-purity ethylene glycol mono-tert-butyl ether, wherein the ionic liquid layer is directly recycled.

2. The method for synthesizing ethylene glycol mono-tert-butyl ether in the basic ionic liquid according to claim 1, characterized in that: the molar ratio of the tertiary butanol to the ethylene oxide is 2-5:1, and the reaction time is 3-8 hours under the condition of heat preservation.

3. The method for synthesizing ethylene glycol mono-tert-butyl ether in the basic ionic liquid according to claim 1, characterized in that: the reaction time is 3-8 hours.

4. The method for synthesizing ethylene glycol mono-tert-butyl ether in the basic ionic liquid according to claim 1, characterized in that: the preparation method of the alkaline ionic liquid comprises the following steps:

1) adding N-methylimidazole and 1-N-butyl bromide into a reactor according to a certain molar ratio, heating to 50-80 ℃, stirring for reacting for 3-10 hours, adding ethyl acetate after the reaction is completed, standing for layering to obtain an organic layer and an ionic liquid layer, washing the ionic liquid layer once again by using ethyl acetate, and performing rotary evaporation to obtain the ionic liquid;

2) dropwise adding the ionic liquid prepared in the step 1) into a methanol solution of sodium imidazolium under a stirring state, stirring and reacting for 5-10 hours at room temperature after dropwise adding, adding deionized water after the reaction is finished, fully stirring and mixing, standing and layering, taking the ionic liquid layer, adding ethyl acetate for washing, standing and layering, taking the ionic liquid layer, and performing rotary evaporation to obtain the alkaline ionic liquid.

5. The method for synthesizing ethylene glycol mono-tert-butyl ether in the basic ionic liquid according to claim 4, characterized in that: the molar ratio of the N-methylimidazole to the 1-N-bromo-butane is 1: 1-1.2.

6. The method for synthesizing ethylene glycol mono-tert-butyl ether in the basic ionic liquid according to claim 4, characterized in that: the molar concentration of the imidazole sodium in the methanol solution is 0.1-0.5mol/L.

7. The method for synthesizing ethylene glycol mono-tert-butyl ether in the basic ionic liquid according to claim 4, characterized in that: the rotary evaporation temperature in the steps 1) and 2) is 60-70 ℃, and the pressure is 20 mmHg.

Technical Field

The invention belongs to the field of organic synthesis, and particularly relates to a method for synthesizing ethylene glycol mono-tert-butyl ether in alkaline ionic liquid.

Background

Ethylene glycol mono-tertiary butyl ether (TMBE) can be mixed with most organic solvents and can dissolve amino/nitro/alkyd/acrylic acid resin. Is miscible with water at room temperature (25 ℃). The solvent is mainly used for latex water dispersion paint in the paint industry, and the HLB value of the solvent is close to 9.0, so that the function of the solvent in a dispersion system plays a role of a dispersant/an emulsifier/a rheological agent/a cosolvent. It can improve the drying speed, the flatness, the brightness and the adhesion fastness of the water dispersible paint. Due to the tertiary butyl structure, the material has higher photochemical stability and safety. The water dispersed paint prepared with the solvent has excellent storage stability, especially in winter.

The printing ink prepared by using the ethylene glycol mono-tertiary butyl ether as a solvent or used as a diluent in the printing ink can greatly improve the rheological property of the printing ink, and improve the quality, the glossiness and the adhesion fastness of high-speed printing. Due to its low toxicity and low irritation, butyl cellosolve has been replaced in the United states, Japan, and Europe for many years, and has been used in large quantities in automotive and architectural coatings, especially in water-dispersed coatings. Ethylene glycol mono-tertiary-butyl ether is generally obtained by the addition reaction of isobutylene and ethylene glycol.

Due to the limited selectivity of the catalyst in the production process, ethylene glycol di-tert-butyl ether is often associated with the generated ethylene glycol di-tert-butyl ether, and the ethylene glycol di-tert-butyl ether have azeotropic property, so that the separation and purification are difficult. There is a document of using azeotropic distillation of diethylene glycol di-t-butyl ether with water at 98-90 ℃, but the azeotropic distillation process requires a large amount of water and is very energy intensive. The literature discloses extractive distillation processes for removing impurities from dipropylene glycol tert-butyl ether using a glycol extractant such as dipropylene glycol.

Chinese patent application No. CN201110159782AX discloses a method for separating glycol alkyl ether compounds by an extraction process using hydrophilic and lipophilic extraction agents. However, the above methods all require the addition of the 3 rd component, and the process flow is very complicated.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a method for synthesizing ethylene glycol mono-tert-butyl ether in alkaline ionic liquid, which has simple process flow and is beneficial to industrial production.

A method for synthesizing ethylene glycol mono-tert-butyl ether in alkaline ionic liquid adopts tert-butyl alcohol and ethylene oxide as reaction raw materials, and takes the alkaline ionic liquid as a catalyst and a solvent, and the specific preparation method is as follows:

adding tert-butyl alcohol into alkaline ionic liquid, stirring uniformly, heating to 30-50 ℃, slowly dropwise adding a tetrahydrofuran solution of ethylene oxide, after dropwise adding, keeping the temperature for reaction for a period of time, after the reaction is finished, standing and layering to obtain an organic phase layer and an ionic liquid layer, distilling the organic layer under reduced pressure to obtain high-purity ethylene glycol mono-tert-butyl ether, and directly recycling the ionic liquid layer; the addition amount of the alkaline ionic liquid is 1-3 times of the mass of the tertiary butanol.

The molar ratio of the tertiary butanol to the ethylene oxide is 2-5:1, and the reaction time is 3-8 hours under the condition of heat preservation.

The preparation method of the alkaline ionic liquid comprises the following steps:

1) adding N-methylimidazole and 1-N-butyl bromide into a reactor according to a certain molar ratio, heating to 50-80 ℃, stirring for reacting for 3-10 hours, adding ethyl acetate after the reaction is completed, standing for layering to obtain an organic layer and an ionic liquid layer, washing the ionic liquid layer once again by using ethyl acetate, and performing rotary evaporation to obtain the ionic liquid;

2) dropwise adding the ionic liquid prepared in the step 1) into a methanol solution of sodium imidazolium under a stirring state, stirring and reacting for 5-10 hours at room temperature after dropwise adding, adding deionized water after the reaction is finished, fully stirring and mixing, standing and layering, taking the ionic liquid layer, adding ethyl acetate for washing, standing and layering, taking the ionic liquid layer, and performing rotary evaporation to obtain the alkaline ionic liquid.

Preferably, the molar ratio of the N-methylimidazole to the 1-N-bromo-butane is 1: 1-1.2;

preferably, the molar concentration of the sodium imidazolium in methanol is 0.1-0.5mol/L.

Preferably, the rotary evaporation in steps 1) and 2) is carried out at a temperature of 60 to 70 ℃ and a pressure of 20 mmHg.

The reaction of tert-butyl alcohol and epoxy ethanol in the presence of an alkaline catalyst is a nucleophilic reaction process, and the alcoholic hydroxyl group in the molecular structure of tert-butyl alcohol has a large space bit group, so that the nucleophilic activity of the alcoholic hydroxyl group is low, even far lower than that of the ring-opening product of tert-butyl alcohol and epoxy ethanol, namely ethylene glycol mono-tert-butyl ether, and therefore, a satisfactory reaction result is generally difficult to obtain by using a common alkaline catalyst.

The ionic liquid adopts the basic ionic liquid, not only has basic groups, but also has methylimidazole cation groups, and is the bifunctional ionic liquid; when the ionic liquid is reacted, the active tert-butyl alcohol can be obtained, the methylimidazole cation in the ionic liquid also has certain activation capacity on ethylene oxide, and the conversion rate of raw materials and the selectivity of products of the reaction are greatly improved through the double activation effect on the tert-butyl alcohol and the ethylene oxide.

According to the invention, ethylene oxide is dropwise added into the ionic liquid solution of tert-butyl alcohol, so that the tert-butyl alcohol always keeps a large excess amount in the reaction process, and the generation of byproducts is reduced to the greatest extent.

The main by-products of the method are the polyethylene glycol tertiary butyl ether which can not generate ethylene glycol di-tertiary butyl ether, the polyethylene glycol tertiary butyl ether and the ethylene glycol mono-tertiary butyl ether can not generate azeotrope, and the separation can be realized through simple distillation.

The invention has the advantages and effects that:

the invention provides a method for synthesizing ethylene glycol mono-tert-butyl ether in alkaline ionic liquid, which is suitable for industrial production, and has the advantages of yield of more than 93 percent, purity of more than 99 percent, simple process and suitability for the requirements of industrial production.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

[ example 1 ]

S1 preparation of basic ionic liquid

1) Adding 1mol of N-methylimidazole and 1.1mol of 1-n-bromo-butane into a reactor, heating to 80 ℃, stirring for reaction for 3 hours, adding ethyl acetate after the reaction is completed, standing for layering to obtain an organic layer and an ionic liquid layer, washing the ionic liquid layer with ethyl acetate once again, and performing rotary evaporation at 70 ℃ and 20mmHg to obtain the ionic liquid;

2) dropwise adding 2L of a 0.5mol/L imidazole sodium methanol solution into the ionic liquid prepared in the step 1) under the stirring state, stirring and reacting for 6 hours at room temperature after dropwise adding, adding deionized water after reaction, fully stirring and mixing, standing and layering, adding ethyl acetate into the ionic liquid layer for washing, standing and layering to obtain an ionic liquid layer, and performing rotary evaporation at 60 ℃ and 20mmHg to obtain the alkaline ionic liquid.

S2 preparation of ethylene glycol mono-tertiary-butyl ether

Adding 0.5mol of tert-butyl alcohol (37g) into 80g of the alkaline ionic liquid prepared in the step S1, uniformly stirring, heating to 30-50 ℃, slowly dropwise adding 1L of ethylene oxide tetrahydrofuran solution with the concentration of 1mol/L, after dropwise adding, keeping the temperature for reacting for 3-8 hours, after the reaction is finished, standing and layering to obtain an organic phase layer and an ionic liquid layer, and carrying out reduced pressure distillation on the organic phase layer to obtain 54.1g (yield is 94.2%) of high-purity ethylene glycol mono-tert-butyl ether, wherein the ionic liquid layer is directly recycled.

[ example 2 ]

S1 preparation of basic ionic liquid

1) Adding 10mol of N-methylimidazole and 12mol of 1-N-butyl bromide into a reactor, heating to 40 ℃, stirring for reaction for 4 hours, adding ethyl acetate after the reaction is completed, standing for layering to obtain an organic layer and an ionic liquid layer, washing the ionic liquid layer with ethyl acetate once again, and performing rotary evaporation at 60 ℃ and 20mmHg to obtain the ionic liquid;

2) dropwise adding the ionic liquid prepared in the step 1) into a methanol solution of imidazole sodium with the molar concentration of 0.1mol/L under the stirring state, stirring and reacting for 10 hours at room temperature after dropwise adding, adding deionized water after reaction, fully stirring and mixing, standing and layering, taking an ionic liquid layer, adding ethyl acetate for washing, standing and layering, taking an ionic liquid layer, and performing rotary evaporation at 70 ℃ and 20mmHg to obtain the alkaline ionic liquid.

S2 preparation of ethylene glycol mono-tertiary-butyl ether

Adding 3mol of tertiary butyl alcohol (222g) into 500g of alkaline ionic liquid, stirring uniformly, heating to 50 ℃, slowly dropwise adding 500mL of 1mol/L ethylene oxide tetrahydrofuran solution, keeping the temperature for 5 hours after dropwise adding, standing and layering after the reaction is finished to obtain an organic phase layer and an ionic liquid layer, and carrying out reduced pressure distillation on the organic phase layer to obtain 111.4g of high-purity ethylene glycol mono-tertiary butyl ether (yield is 94.2%), wherein the ionic liquid layer is directly recycled.

[ example 3 ]

S1 preparation of basic ionic liquid

1) Adding 1mol N-methylimidazole and 1.2mol 1-n-bromo-butane into a reactor, heating to 80 ℃, stirring for reaction for 5 hours, adding ethyl acetate after the reaction is completed, standing for layering to obtain an organic layer and an ionic liquid layer, washing the ionic liquid layer with ethyl acetate once again, and performing rotary evaporation at 70 ℃ and 20mmHg to obtain the ionic liquid;

2) dropwise adding the ionic liquid prepared in the step 1) into a methanol solution of imidazole sodium with the molar concentration of 0.5mol/L under the stirring state, stirring and reacting for 10 hours at room temperature after dropwise adding, adding deionized water after reaction, fully stirring and mixing, standing and layering, taking an ionic liquid layer, adding ethyl acetate for washing, standing and layering, taking an ionic liquid layer, and performing rotary evaporation at 70 ℃ and 20mmHg to obtain the alkaline ionic liquid.

S2 preparation of ethylene glycol mono-tertiary-butyl ether

Adding 3mol of tertiary butyl alcohol (222g) into 250g of alkaline ionic liquid with the mass times, uniformly stirring, heating to 40 ℃, slowly dropwise adding 1L of ethylene oxide tetrahydrofuran solution with the concentration of 1mol/L, after dropwise adding, keeping the temperature for reaction for 4 hours, after the reaction is finished, standing and layering to obtain an organic phase layer and an ionic liquid layer, and carrying out reduced pressure distillation on the organic phase layer to obtain 110.4g (the yield is 93.6%) of high-purity ethylene glycol mono-tertiary butyl ether, wherein the ionic liquid layer is directly recycled.

The foregoing description has disclosed fully preferred embodiments of the present invention. It should be noted that those skilled in the art can make modifications to the embodiments of the present invention without departing from the scope of the appended claims. Accordingly, the scope of the appended claims is not to be limited to the specific embodiments described above.