Process for the one-pot synthesis of ethylhexylglycerin

Abstract

This invention belongs to the field of organic synthesis technology and discloses a one-pot method for synthesizing ethylhexylglycerol, which includes the following steps: (1) mixing isooctanol, ketone solvent and strong base, heating and raising the temperature, and adding epichlorohydrin dropwise while keeping it warm. After the addition is completed, the reaction is kept warm until the epichlorohydrin reaction is completed; after the reaction is completed, the reaction solution is neutralized, the salts generated by the side reaction are removed by layering and the excess base is neutralized; the solution is washed with water, concentrated to remove water, and an acidic catalyst is added to the concentrated solution after dehydration, and the solution is heated and stirred to carry out the cyclization reaction; (4) after the reaction is completed, an aqueous formic acid solution is added to the reaction solution to carry out the hydrolysis reaction. During the reaction, ketones and formic acid are distilled out, and the aqueous layer is returned to the hydrolysis system until the hydrolysis reaction is completed; (5) after the reaction is completed, the ketone solvent and formic acid are recovered by distillation, and then ethylhexylglycerol is obtained by vacuum distillation. This invention solves the problems of multiple solvent types, complex reaction and unsmooth process in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis technology and relates to the preparation of a daily chemical additive, particularly a one-pot method for synthesizing ethylhexylglycerin. Background Technology

[0002] Ethylhexylglycerin (scientific name 3-(2-ethylhexyloxy)-1,2-propanediol) is a novel, multifunctional nonionic surfactant. It can be used as a preservative, antibacterial agent, deodorant, emollient, synergist, emulsifier, plasticizer, octane number improver, defoamer, and other additives, and possesses biological benefits. Currently, it is mainly used in the daily chemical industry and is a globally recognized, non-toxic, and harmless organic preservative.

[0003] Currently, the reported methods for synthesizing ethylhexylglycerol mainly fall into two categories: glycidyl ether method and glycidyl ester method. The glycidyl ether method is further divided into acetone carbonyl addition method, acetic anhydride esterification method, sodium acetate hydrolysis method, and bio-enzymatic hydrolysis method. Due to the relatively recent development and application of ethylhexylglycerol, existing synthesis methods suffer from long process routes, complex reactions, and high product prices, severely limiting its application. Therefore, my country currently relies heavily on imports for ethylhexylglycerol.

[0004] In order to reduce product costs, it is necessary to develop a synthesis process that is short, simple, quick, high-yield, low-cost, and environmentally friendly as soon as possible, so that ethylhexylglycerol can be produced easily, cheaply, and widely used. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a one-pot method for synthesizing ethylhexylglycerol. The present invention involves reacting in a ketone solvent to form a ketal, which is then hydrolyzed to ethylhexylglycerol. This solves the problems of existing technologies, such as the use of multiple solvents, complex reactions, and unsmooth processes.

[0006] This invention is achieved through the following technical solution:

[0007] A one-pot method for synthesizing ethylhexylglycerol includes the following steps:

[0008] (1) Mix isooctyl alcohol, ketone solvent and strong base, heat and raise the temperature, add epichlorohydrin dropwise while keeping the temperature, and continue to keep the temperature until the epichlorohydrin reaction is complete.

[0009] (2) After the reaction is complete, add water to the reaction solution and use acid to neutralize and separate the salts produced by the side reaction and remove excess alkali;

[0010] (3) The reaction solution was further washed with water to separate the layers. The resulting organic layer was concentrated to remove water. After dehydration, an acidic catalyst was added to the concentrate, and the mixture was heated and stirred to carry out a cyclization reaction to obtain 4-alkoxymethyl-1,3-dioxane.

[0011] (4) After the reaction is completed, add formic acid aqueous solution to the reaction solution to carry out hydrolysis reaction. During the reaction, ketones and formic acid are distilled out, and the aqueous layer is returned to the hydrolysis system. Ethylhexylglycerol crude product is obtained after the hydrolysis reaction is completed.

[0012] (5) After the reaction is complete, the layers are separated, neutralized, washed with water, and distilled under reduced pressure to obtain ethylhexylglycerol.

[0013] The reaction equation is as follows:

[0014]

[0015]

[0016]

[0017] A further improvement to the present invention is as follows:

[0018] The ketone solvent mentioned in step (1) is a hydrophobic ketone with 4-7 carbon atoms.

[0019] Furthermore, the ketone solvent is preferably one or a mixture of two or more selected from butanone, 3-pentanone, 2-pentanone, cyclohexanone, MIBK, methyl isopropanone, methyl amyl ketone, cyclohexanone, cyclopentanone, and 2-hexanone. The mass ratio of the ketone solvent to epichlorohydrin is 4-6:1.

[0020] Furthermore, the strong base mentioned in step (1) is sodium hydroxide or potassium hydroxide, or a mixture of both. The molar ratio of isooctanol, the strong base, and epichlorohydrin is 1.05–1.15:1.02–1.05:1.0

[0021] Furthermore, the temperature for heating and holding in step (1) is 30–60°C;

[0022] Furthermore, a phase transfer catalyst can be added in step (1) to accelerate the reaction rate. The phase transfer catalyst is a quaternary ammonium salt, such as tetrabutylammonium bromide, dodecyltrimethylammonium chloride, etc., and the weight of the phase transfer catalyst and epichlorohydrin is 0.1-1.5%. Furthermore, the acid in step (2) can be one or more of hydrochloric acid, sulfuric acid, or acetic acid, preferably hydrochloric acid. The pH after neutralization is 5-8. Generally, the weight of the water is 3-5 times the mass of the hydrochloric acid salt produced by the side reaction to ensure the full dissolution of the byproduct sodium chloride, while also preventing the wastewater volume from becoming too large.

[0023] Furthermore, the acidic catalyst in step (3) is one or more of boron trifluoride, phosphotungstic acid, or sulfonic acid-type acidic resin, and the mass ratio of the catalyst to epichlorohydrin is 1-5%. During the dehydration process, the water content in the solution after dehydration does not exceed 0.1%, so that the cyclization reaction can proceed well. The temperature of the cyclization reaction in step (3) is 35-80℃, and the reaction time is 2-8 hours.

[0024] The acid-water solution in step (4) is a formic acid-water solution. In this invention, the ketone solvent is separated from the reaction system through the azeotropic reaction of water and the added ketone solvent. Since the formic acid carried over during distillation is dissolved in water, it can be returned to the hydrolysis system through a simple layering operation, which is beneficial for the further progress of the reaction. In addition, the water in the system participates in the reaction to hydrolyze 4-alkoxymethyl-1,3-dioxane to obtain the product. The concentration of formic acid in the formic acid-water solution in the system is 45-50%.

[0025] The aqueous layer in step (5) is a formic acid solution, which can be used in the hydrolysis reaction. The organic layer is neutralized with alkali to a pH of 6-8. The vacuum distillation temperature is 135-145 °C and the vacuum degree is 80-120 Pa.

[0026] The advantages of this invention are:

[0027] The ketone solvent used in this invention has lower toxicity than toluene in the prior art, and the solvent is easy to recover and reuse after distillation, making it safer and more environmentally friendly than the prior art.

[0028] This invention involves multiple steps of reaction in the same reaction solvent, with fewer post-treatment solvent purification and recovery steps, making it easy to operate.

[0029] The acid used in the hydrolysis reaction of this invention can be simply separated into layers before it can be reused, making it easy to recycle. Detailed Implementation

[0030] The present invention will now be described in detail with reference to specific embodiments.

[0031] Example 1:

[0032] (1) Solid sodium hydroxide (90.78 g, 1.05 eq.), 3-pentanone (800 g), 2-ethylhexanol (309.65 g, 1.1 eq.), and tetrabutylammonium bromide (2.0 g, 1% w / w) were added sequentially to a three-necked flask and stirred to dissolve. Epichlorohydrin (200 g, 1.0 eq.) was added dropwise at 30-35 °C, and the reaction was maintained at this temperature for 4 h. The reaction temperature was then lowered to 20-30 °C.

[0033] (2) After adding water (630 g) and stirring evenly, the reaction product was neutralized to pH 6-8 by adding hydrochloric acid aqueous solution (concentration: 10%, 39.5 g); the layers were separated, and the aqueous layer was sodium chloride solution;

[0034] (3) Wash the organic layer with water (200 g), separate the layers, and remove the water layer for wastewater treatment. Heat the organic layer (110-120℃) and distill at atmospheric pressure to further remove water (the water content of the system is 0.06%); cool down to 40-80℃ and add boron trifluoride ether (2.0 g, 1.0% w / w); heat at 35-45℃ and stir for 6-7 hours to carry out the cyclization reaction to obtain 4-alkoxymethyl-1,3-dioxane;

[0035] (4) After the reaction is complete, add formic acid solution (concentration: 50%, 400 g, 2.0 eq.) to the reaction solution and carry out hydrolysis at 80-95℃. At the same time, the solvent 3-pentanone (azeotropic point: 82-83℃) is recovered by azeotropic reaction. The aqueous layer of the obtained azeotropic solution is returned to the reaction system. The obtained 3-pentanone (about 720 g) is washed with water and separated into layers and then used in step (1).

[0036] (5) After the hydrolysis reaction is completed, the temperature is lowered to 20-30℃, and the layers are separated. The aqueous layer (450 g, containing a small amount of organic material) is reused. The organic layer is neutralized to pH 6-8 with sodium hydroxide aqueous solution. After washing with water, it is distilled under reduced pressure (80 Pa, 135-145℃) to obtain 287 g of ethylhexylglycerol, with a yield of 65% and a purity of 99.1%.

[0037] Example 2:

[0038] (1) Solid sodium hydroxide (90.78 g, 1.05 eq.), MIBK (800 g), 2-ethylhexanol (309.65 g, 1.1 eq.), and tetrabutylammonium bromide (3.0 g, 1.5% w / w) were added sequentially to a three-necked flask, stirred and dissolved, and epichlorohydrin (200 g, 1.0 eq.) was added dropwise at 35-40 ℃. The reaction was maintained at this temperature for 4 h, and then the reaction temperature was lowered to 20-30 ℃.

[0039] (2) After adding water (380 g) and stirring evenly, the reaction product is neutralized to pH 6-8 by adding hydrochloric acid aqueous solution (concentration: 15%, 52.5 g); the layers are separated, and the aqueous layer is sodium chloride solution for wastewater treatment;

[0040] (3) Wash the organic layer with water (200 g), separate the layers, and remove the water layer for wastewater treatment. Heat the organic layer (125-135℃) and distill at atmospheric pressure to further remove water (the system contains 0.03% water); cool down to 40-80℃ and add boron trifluoride ether (6.0 g, 3% w / w); heat at 40-50℃ and stir for 4-5 hours to carry out a cyclization reaction to obtain 4-alkoxymethyl-1,3-dioxane;

[0041] (4) After the reaction is complete, add formic acid solution (concentration: 85%, 234 g, 2.0 eq.) and 200 g of water to the reaction solution, and heat to 80-95℃ to carry out hydrolysis reaction. At the same time, the solvent MIBK (azeotropic point: 87-88℃) is recovered by azeotropic reaction. The aqueous layer of the obtained azeotropic solution is returned to the reaction system. The obtained MIBK (about 800 g) is washed with water and separated into layers and then used in step (1).

[0042] (5) After the hydrolysis reaction is completed, the temperature is lowered to 20-30℃, and the layers are separated. The aqueous layer (450 g, containing a small amount of organic material) is reused. The organic layer is neutralized to pH 6-8 with sodium hydroxide aqueous solution (concentration 5%). After washing with water, it is distilled under reduced pressure (80 Pa, 135-145℃) to obtain 300 g of ethylhexylglycerol, with a yield of 68% and a purity of 99.6%.

[0043] Example 3:

[0044] (1) Add solid sodium hydroxide (90.78 g, 1.05 eq.), 2-pentanone (1000 g), 2-ethylhexanol (309.65 g, 1.10 eq.), and tetrabutylammonium bromide (1.0 g, 0.5% w / w) sequentially to a three-necked flask, stir to dissolve, and add epichlorohydrin (200 g, 1.0 eq.) dropwise at 55-60 ℃. Maintain the reaction temperature for 4 h, then lower the reaction temperature to 20-30 ℃.

[0045] (2) After adding water (440 g) and stirring evenly, the reaction product is neutralized to pH 6-8 by adding hydrochloric acid aqueous solution (concentration: 15%, 26.3 g); the layers are separated, and the aqueous layer is sodium chloride solution for wastewater treatment;

[0046] (3) The organic layer was washed with water (200 g), and the layers were separated. The water layer was treated with wastewater. The organic layer was heated (110-120℃) and dehydrated by atmospheric distillation (the water content of the system was 0.02%). Then the temperature was lowered to 35℃, and boron trifluoride ether (10 g, 5.0% w / w) was added dropwise. The mixture was heated to 40-50℃ and stirred for 5-6 hours to carry out a cyclization reaction to obtain 4-alkoxymethyl-1,3-dioxane.

[0047] (4) After the reaction is complete, add formic acid solution (concentration: 85%, 234 g, 2.0 eq.) and 200 g of water to the reaction solution, and raise the temperature to 80-95℃ to carry out hydrolysis reaction. At the same time, the solvent 2-pentanone (azeotropic point: 83-85℃) is recovered by azeotropic reaction. The aqueous layer of the obtained azeotropic solution is returned to the reaction system. The obtained 2-pentanone (about 1000 g) is washed with water and separated into layers and then reused in step (1).

[0048] (5) After the hydrolysis reaction is completed, the temperature is lowered to 20-30℃, and the layers are separated. The aqueous layer (450 g, containing a small amount of organic material) is reused. The organic layer is neutralized to pH 6-8 with sodium carbonate (10% concentration) aqueous solution. After washing with water, it is distilled under reduced pressure (80-100 Pa, 135-145℃) to obtain 309 g of ethylhexylglycerol, with a yield of 70% and a purity of 99.4%.

[0049] Example 4:

[0050] (1) Solid sodium hydroxide (88.19 g, 1.02 eq.), methyl isopropanone (1000 g), 2-ethylhexanol (295.58 g, 1.05 eq.), and dodecyltrimethylammonium chloride (1.0 g, 0.5% w / w) were added sequentially to a three-necked flask, stirred to dissolve, and epichlorohydrin (200 g, 1.0 eq.) was added dropwise at 40-45 ℃. The reaction was maintained at this temperature for 4 h, and then the reaction temperature was lowered to 20-30 ℃.

[0051] (2) After adding water (450 g) and stirring evenly, the reaction product is neutralized to pH 6-8 by adding hydrochloric acid aqueous solution (concentration: 15%, 10.5 g); the layers are separated, and the aqueous layer is sodium chloride solution for wastewater treatment;

[0052] (3) Wash the organic layer with water (200 g), separate the layers, and remove the water layer for wastewater treatment. Heat the organic layer (110-120℃) and dehydrate it by atmospheric distillation (system water content 0.03%). Then cool it to 35℃ and add phosphotungstic acid (10.0 g, 5.0% w / w); heat it at 55-65℃ for 2-3 hours and stir to carry out the cyclization reaction to obtain 4-alkoxymethyl-1,3-dioxane;

[0053] (4) After the reaction is complete, add formic acid solution (concentration: 45%, 433 g, 2.0 eq.) to the reaction solution, raise the temperature to 80-95℃ to carry out hydrolysis reaction, and simultaneously recover the solvent methyl isopropanone (azeotropic point: 78-80℃) through azeotropic reaction; return the aqueous layer of the obtained azeotropic solution to the reaction system; the recovered ketone (about 1000 g) is washed with water and separated into layers and then reused in step (1);

[0054] (5) After the hydrolysis reaction is completed, the temperature is lowered to 20-30℃, and the layers are separated. The aqueous layer (450 g, containing a small amount of organic material) is reused. The organic layer is neutralized to pH 6-8 with sodium bicarbonate aqueous solution (concentration 6%). After washing with water, it is distilled under reduced pressure (80-100 Pa, 135-145℃) to obtain 318 g of ethylhexylglycerol, with a yield of 72% and a purity of 99.5%.

[0055] Example 5:

[0056] (1) Solid sodium hydroxide (88.19 g, 1.02 eq.), methyl pentyl ketone (600 g), 2-ethylhexanol (295.58 g, 1.05 eq.), and tetrabutylammonium bromide (1.0 g, 0.5% w / w) were added sequentially to a three-necked flask, stirred to dissolve, and epichlorohydrin (200 g, 1.0 eq.) was added dropwise at 40-45 ℃. The reaction was maintained at this temperature for 4 h, and then the reaction temperature was lowered to 20-30 ℃.

[0057] (2) After adding water (568 g) and stirring evenly, the reaction product is neutralized to pH 6-8 by adding sulfuric acid aqueous solution (concentration: 15%, 14.2 g); the layers are separated, and the aqueous layer is sodium chloride solution for wastewater treatment;

[0058] (3) Wash the organic layer with water (200 g), separate the layers, and remove the water layer for wastewater treatment. Heat the organic layer (80-90℃) and dehydrate it by vacuum distillation (system water content 0.08%). Then cool it to 35℃ and add phosphotungstic acid (8 g, 4.0% w / w); heat it and keep it at 65-75℃ for 3-4 hours to carry out the cyclization reaction to obtain 4-alkoxymethyl-1,3-dioxane;

[0059] (4) After the reaction is complete, add formic acid solution (concentration: 45%, 433 g, 2.0 eq.) to the reaction solution, raise the temperature to 80-95℃ to carry out hydrolysis reaction, and simultaneously recover the solvent methyl pentyl ketone (azeotropic point: 95-96℃) through azeotropic reaction; return the aqueous layer of the obtained azeotropic solution to the reaction system; the recovered ketone (about 600 g) is washed with water and separated into layers and then reused in step (1);

[0060] (5) After the hydrolysis reaction is completed, the temperature is lowered to 20-30℃, and the layers are separated. The aqueous layer (450 g, containing a small amount of organic material) is reused. The organic layer is neutralized to pH 6-8 with sodium bicarbonate solution (5% concentration). After washing with water, it is distilled under reduced pressure (80-100 Pa, 135-145℃) to obtain 274 g of ethylhexylglycerol, with a yield of 63% and a purity of 99.2%.

[0061] Example 6:

[0062] (1) Solid sodium hydroxide (88.19 g, 1.02 eq.), cyclohexanone (900 g), 2-ethylhexanol (295.58 g, 1.05 eq.), and tetrabutylammonium bromide (1.0 g, 0.5% w / w) were added sequentially to a three-necked flask, stirred to dissolve, and epichlorohydrin (200 g, 1.0 eq.) was added dropwise at 45-55 ℃. The reaction was maintained at this temperature for 4 h, and then the reaction temperature was lowered to 20-30 ℃.

[0063] (2) After adding water (380 g) and stirring evenly, the reaction product is neutralized to pH 6-8 by adding acetic acid (2.6 g); the layers are separated, and the aqueous layer is a sodium chloride solution for wastewater treatment.

[0064] (3) Wash the organic layer with water (200 g), separate the layers, and remove the water layer for wastewater treatment. Heat the organic layer (80-90℃) and dehydrate it by vacuum distillation (system water content 0.01%). Then cool it to 35℃ and add phosphotungstic acid (2.0 g 1.0% w / w); heat it at 70-80℃ and stir for 5-6 hours to carry out a cyclization reaction to obtain 4-alkoxymethyl-1,3-dioxane;

[0065] (4) After the reaction is complete, add formic acid solution (concentration: 45%, 433 g, 2.0 eq.) to the reaction solution, raise the temperature to 80-95℃ to carry out hydrolysis reaction, and simultaneously recover the solvent cyclohexanone (azeotropic point: 95-96℃) through azeotropic reaction; return the aqueous layer of the obtained azeotropic solution to the reaction system; the recovered cyclohexanone (about 900 g) is washed with water and separated into layers and then reused in step (1);

[0066] (5) After the hydrolysis reaction is completed, the temperature is lowered to 20-30℃, and the layers are separated. The aqueous layer (450 g, containing a small amount of organic material) is reused. The organic layer is neutralized to pH 6-8 with sodium bicarbonate aqueous solution (concentration 3%). After washing with water, it is distilled under reduced pressure (80-100 Pa, 135-145℃) to obtain 274 g of ethylhexylglycerol, with a yield of 63% and a purity of 99.2%.

[0067] Example 7:

[0068] (1) Solid sodium hydroxide (88.19 g, 1.02 eq.), cyclopentanone (900 g), 2-ethylhexanol (298.39 g, 1.06 eq.), and tetrabutylammonium bromide (0.2 g, 0.1% w / w) were added sequentially to a three-necked flask, stirred to dissolve, and epichlorohydrin (200 g, 1.0 eq.) was added dropwise at 45-50 ℃. The reaction was maintained at this temperature for 4 h, and then the reaction temperature was lowered to 20-30 ℃.

[0069] (2) After adding water (420 g) and stirring evenly, the reaction product is neutralized to pH 6-8 by adding hydrochloric acid aqueous solution (concentration: 15%, 10.5 g); the layers are separated, and the aqueous layer is sodium chloride solution for wastewater treatment.

[0070] (3) Wash the organic layer with water (200 g), separate the layers, and remove the water layer for wastewater treatment. Heat the organic layer (80-90℃) and dehydrate it by vacuum distillation (system water content 0.1%). Then cool it to 20℃ and add phosphotungstic acid (6.0 g, 3.0% w / w); heat and keep it at 60-70℃ and stir for 2-3 hours to carry out the cyclization reaction to obtain 4-alkoxymethyl-1,3-dioxane;

[0071] (4) After the reaction is complete, add formic acid solution (concentration: 45%, 476 g, 2.2 eq.) to the reaction solution, raise the temperature to 80-95℃ to carry out hydrolysis reaction, and simultaneously recover the solvent cyclopentanone (azeotropic point: 90-92℃) through azeotropic reaction; return the aqueous layer of the obtained azeotropic solution to the reaction system; the recovered cyclopentanone (about 900 g) is washed with water and separated into layers and then reused in step (1);

[0072] (5) After the hydrolysis reaction is completed, the temperature is lowered to 20-30℃, and the layers are separated. The aqueous layer (480 g, containing a small amount of organic material) is reused. The organic layer is neutralized to pH 6-8 with potassium carbonate aqueous solution (concentration 5%). After washing with water, it is distilled under reduced pressure (80-100 Pa, 135-145℃) to obtain 300 g of ethylhexylglycerol, with a yield of 68% and a purity of 99.4%.

[0073] Example 8:

[0074] (1) Solid sodium hydroxide (89.92 g, 1.04 eq.), 3-pentanone (1200 g), 2-ethylhexanol (323.73 g, 1.15 eq.), and dodecyltrimethylammonium chloride (0.4 g, 0.2% w / w) were added sequentially to a three-necked flask, stirred to dissolve, and epichlorohydrin (200 g, 1.0 eq.) was added dropwise at 55-60 ℃. The reaction was maintained at this temperature for 4 h, and then the reaction temperature was lowered to 20-30 ℃.

[0075] (2) After adding water (400 g) and stirring evenly, the reaction product is neutralized to pH 6-8 by adding hydrochloric acid aqueous solution (concentration: 15%, 21.03 g); the layers are separated, and the aqueous layer is sodium chloride solution for wastewater treatment;

[0076] (3) Wash the organic layer with water (200 g), separate the layers, and remove the water layer for wastewater treatment. Heat the organic layer (80-90℃) and dehydrate it by vacuum distillation (system water content 0.04%). Then cool it to 35℃ and add sulfonic acid resin (10.0 g 5.0% w / w); heat and keep it at 55-65℃ and stir for 6-8 hours to carry out the cyclization reaction to obtain 4-alkoxymethyl-1,3-dioxane;

[0077] (4) After the reaction is complete, filter and recover the resin; add formic acid solution (concentration: 45%, 455 g, 2.1 eq.) to the reaction solution, heat to 80-95℃ to carry out hydrolysis reaction, and simultaneously recover the solvent 3-pentanone (azeotropic point: 82-83℃) through azeotropic reaction; return the aqueous layer of the obtained azeotropic solution to the reaction system; the recovered 3-pentanone (about 1200 g) is washed with water and separated into layers and then reused in step (1);

[0078] (5) After the hydrolysis reaction is completed, the temperature is lowered to 20-30℃, and the layers are separated. The aqueous layer (470 g, containing a small amount of organic material) is reused. The organic layer is neutralized to pH 6-8 with sodium bicarbonate aqueous solution (concentration 3%). After washing with water, it is distilled under reduced pressure (80-100 Pa, 135-145℃) to obtain 287 g of ethylhexylglycerol, with a yield of 65% and a purity of 99.6%.

[0079] Example 9:

[0080] (1) Add solid sodium hydroxide (90.78 g, 1.05 eq.), 2-hexanone (1200 g), 2-ethylhexanol (304.02 g, 1.08 eq.), and tetrabutylammonium bromide (0.4 g, 0.2% w / w) sequentially to a three-necked flask, stir to dissolve, and add epichlorohydrin (200 g, 1.0 eq.) dropwise at 45-50 ℃. Maintain the reaction temperature for 4 h, then lower the reaction temperature to 20-30 ℃.

[0081] (2) After adding water (500 g) and stirring evenly, the reaction product is neutralized to pH 6-8 by adding hydrochloric acid aqueous solution (concentration: 15%, 26.30 g); the layers are separated, and the aqueous layer is sodium chloride solution for wastewater treatment;

[0082] (3) Wash the organic layer with water (200 g), separate the layers, and remove the water layer for wastewater treatment. Heat the organic layer (65-75℃) and dehydrate it by vacuum distillation (system water content 0.04%). Then cool it to 35℃ and add sulfonic acid resin (8.0 g, 4.0% w / w); heat and keep at 45-55℃ and stir for 8-10 hours to carry out the cyclization reaction to obtain 4-alkoxymethyl-1,3-dioxane;

[0083] (4) After the reaction is complete, filter and recover the resin; add formic acid solution (concentration: 45%, 433 g, 2.0 eq.) to the reaction solution, heat to 80-95℃ to carry out hydrolysis reaction, and simultaneously recover the solvent 2-hexanone (azeotropic point: 90-92℃) through azeotropic reaction; return the aqueous layer of the obtained azeotropic solution to the reaction system; the recovered 2-hexanone (about 1200 g) is washed with water and separated into layers and then reused in step (1);

[0084] (5) After the hydrolysis reaction is completed, the temperature is lowered to 20-30℃, and the layers are separated. The aqueous layer (460 g, containing a small amount of organic material) is reused. The organic layer is neutralized to pH 6-8 with sodium bicarbonate aqueous solution (concentration 5%). After washing with water, it is distilled under reduced pressure (80-100 Pa, 135-145℃) to obtain 287 g of ethylhexylglycerol, with a yield of 63% and a purity of 99.5%.

[0085] Example 10:

[0086] (1) Solid potassium hydroxide (127.11 g, 1.05 eq.), 2-butanone (900 g), 2-ethylhexanol (309.65 g, 1.10 eq.), and tetrabutylammonium bromide (0.8 g, 0.4% w / w) were added sequentially to a three-necked flask, stirred to dissolve, and epichlorohydrin (200 g, 1.0 eq.) was added dropwise at 45-50 ℃. The reaction was maintained at this temperature for 4 h, and then the reaction temperature was lowered to 20-30 ℃.

[0087] (2) After adding water (450 g) and stirring evenly, the reaction product is neutralized to pH 6-8 by adding hydrochloric acid aqueous solution (concentration: 15%, 26.30 g); the layers are separated, and the aqueous layer is potassium chloride solution for wastewater treatment;

[0088] (3) Wash the organic layer with water (200 g), separate the layers, and remove the water layer for wastewater treatment. Heat the organic layer (65-75℃) and dehydrate it by vacuum distillation (system water content 0.05%). Then cool it to 25℃ and add p-toluenesulfonic acid (5.0 g, 2.5% w / w); heat and keep it at 35-45℃ and stir for 10-12 hours to carry out the cyclization reaction to obtain 4-alkoxymethyl-1,3-dioxane;

[0089] (4) After the reaction is complete, add formic acid solution (concentration: 45%, 433 g, 2.0 eq.) to the reaction solution, raise the temperature to 80-95℃ to carry out hydrolysis reaction, and simultaneously recover the solvent 2-hexanone (azeotropic point: 90-92℃) through azeotropic reaction; return the aqueous layer of the obtained azeotropic solution to the reaction system; the recovered 2-hexanone (about 900 g) is washed with water and separated into layers and then reused in step (1);

[0090] (5) After the hydrolysis reaction is completed, the temperature is lowered to 20-30℃, and the layers are separated. The aqueous layer (460 g, containing a small amount of organic material) is reused. The organic layer is neutralized to pH 6-8 with sodium bicarbonate aqueous solution (concentration 2%). After washing with water, it is distilled under reduced pressure (80-100 Pa, 135-145℃) to obtain 265 g of ethylhexylglycerol, with a yield of 60% and a purity of 99.2%.

[0091] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A process for the synthesis of ethylhexylglycerol in one pot, characterized in that, The method comprises the following steps: (1) mixing isooctanol, methyl isopropyl ketone, dodecyl trimethyl ammonium chloride and strong base, heating and warming, adding dropwise epichlorohydrin under insulation, continuing to react after the dropwise addition is completed until the reaction of epichlorohydrin is completed; (2) after the reaction is completed, adding water to the reaction solution, neutralizing with acid, removing the salt and excess base generated in the side reaction by layering; (3) continuing to wash the reaction solution with water and separating the layers, concentrating and removing water from the obtained organic layer, adding phosphotungstic acid to the concentrated solution after dehydration, and heating and stirring to perform cyclization reaction; (4) after the reaction is completed, adding aqueous formic acid to the reaction solution to perform hydrolysis reaction, distilling ketones and formic acid during the reaction process, returning the water layer to the hydrolysis system until the hydrolysis reaction is completed; (5) after the reaction is completed, recovering ketone solvents and formic acid by distillation, and obtaining ethylhexyl glycerol by vacuum distillation.

2. The process for one pot synthesis of ethylhexyl glycerin as claimed in claim 1 wherein: The strong base in step (1) is sodium hydroxide or potassium hydroxide or a mixture of the two.

3. The process for one pot synthesis of ethylhexylglycerol as claimed in claim 1 wherein: The acid in step (2) is one or a mixture of more than two of hydrochloric acid, sulfuric acid or acetic acid.

4. The process for one pot synthesis of ethylhexylglycerol as claimed in claim 1 wherein: The temperature for dropwise addition and insulation reaction in step (1) is 30-60°C.

5. The process for one pot synthesis of ethylhexylglycerol as claimed in claim 1 wherein: In step (2), the neutralization is to pH 6-8, and the weight of water is 3-5 times the mass of the hydrochloride salt generated in the side reaction.

6. The process for one pot synthesis of ethylhexylglycerol as claimed in claim 1 wherein: The temperature for cyclization reaction in step (3) is 35-80°C, and the water content in the solution after dehydration is not more than 0.1%.

7. The process for one pot synthesis of ethylhexylglycerol as claimed in claim 1, wherein: The molar ratio of isooctanol, strong base and epichlorohydrin in step (1) is 1.05-1.15:1.02-1.05:1.0.

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