Preparation method of electronic-grade 1, 3-propane sultone

Abstract

The invention relates to a preparation method of electronic grade 1.3-propane sultone. The preparation method comprises the following steps: (S1) adding a hydrophobic organic solvent with a low boiling point into industrial grade propane sultone, and diluting to obtain a propane sultone solution; (S2) adding a dewatering agent, stirring, dehydrating, and carrying out reduced pressure distillation on the obtained material to remove the solvent and the acid; the water removal agent comprises an acyl chloride compound; (S3) enabling the obtained substance to enter deacidification resin for cyclic deacidification treatment to obtain a propane sultone solution of which the acidity is lower than 50ppm; and (S4) carrying out solvent removal and vacuum distillation on the obtained low-moisture and low-acidity propane sultone solution to obtain the electronic-grade 1, 3-propane sultone with low moisture, low acidity and high content. According to the method, trace water in a system is thoroughly removed through the acyl chloride acidic water removal agent, preparation of the electronic-grade 1, 3-propane sultone is achieved, the purity is larger than 99%, the water content is lower than 20 ppm, the acidity is lower than 20 ppm, and the yield is larger than 92%.

Description

Technical Field

[0001] The invention relates to a method for preparing an electronic-grade organic compound, in particular to a method for preparing electronic-grade 1,3-propane sultone. Background Art

[0002] 1,3-Propane sultone, referred to as 1,3-PS, is widely used as an organic synthesis intermediate. It is often used in the synthesis of electroplating intermediates and inks in industry. It is an important sulfopropylation reagent and is widely used in the pharmaceutical chemical industry. 1,3-Propane sultone with a water content of less than 100ppm, a content of more than 99.5%, and an acidity of less than 100ppm can be used as an additive for lithium battery electrolytes, and has broad market prospects. Many research institutions at home and abroad have developed a variety of preparation methods for electronic grade 1.3-PS, such as:

[0003] Patent CN201510355390 uses a composite deacidification and dehydration agent to remove the moisture and acidity of propane sultone, and combines it with vacuum distillation to obtain electronic grade 1,3-PS. The deacidification and dehydration agents applicable to this method are organic bases and carbodiimide substances, which increase the risk of 1,3-PS hydrolysis and have a low yield.

[0004] Patent CN201410147908 mentions the use of calcium oxide, sodium methoxide and other substances combined with vacuum distillation to remove the moisture and acidity of propane sultone. This method increases the risk of propane sultone decomposition and also increases the risk of excessive metal ions in electronic-grade propane sultone, especially sodium ions.

[0005] Patent CN201210015838 uses strong alkali water washing, extractive atmospheric distillation, and negative pressure distillation to remove free acid from propane sultone to obtain electronic grade propane sultone. This method increases the difficulty of controlling the moisture content of the product.

[0006] Patent CN2017102822451 puts industrial-grade 1,3-PS into a reactor equipped with molecular sieves and allows it to stand, then performs vacuum distillation, removes impurities with a disc-type nanofiltration membrane, and performs membrane concentration with a disc-tube reverse osmosis device, and finally continuously passes through molecular sieves to obtain electronic-grade 1,3-PS with an acid value of 0-50ppm, a water content of 0-80ppm, and a sodium ion content of 5-10ppm. However, this method is complicated and not suitable for large-scale industrial production.

[0007] CN018115021649 recrystallizes industrial-grade 1,3-propane sultone with an anhydrous organic solvent, separates crystals, and distills the crystals to separate water and impurities under full reflux to obtain electronic-grade 1,3-propane sultone. However, the product yield is low.

[0008] There are also prior art reports on methods for preparing electronic grade 1,3-PS by combining vacuum distillation with melt crystallization, which utilizes the large difference between the melting points of impurities and 1,3-PS to improve the purity of the product by melt crystallization. However, additional melt crystallization equipment is required, and the acid value cannot be effectively controlled.

[0009] In summary, as the new energy industry has higher and higher requirements for lithium battery additives, a lot of research has been done on the methods of electronic-grade propane sultone at home and abroad, but the effect is not obvious and it is difficult to meet market demand. Therefore, it is particularly important to develop a simple and economical method for preparing electronic-grade 1,3-propane sultone. Summary of the invention

[0010] In order to solve the problems that the prior art electronic grade 1,3-propane sultone preparation method is complicated, costly, and may also have the risk of product hydrolysis or excessive metal ions. The purpose of the present invention is to develop a method for preparing electronic grade 1.3-propane sultone, by using an acidic dehydrating agent to completely remove trace water in the system, then by concentrating and deacidifying to remove the acid, and finally by desolventizing and vacuum distillation, the preparation of electronic grade 1,3-propane sultone is achieved, the purity is greater than 99%, the water content is less than 20ppm, the acidity is less than 20ppm, and the yield is greater than 92%, and the preferred embodiment can reach 97%.

[0011] The technical solution adopted by the present invention is:

[0012] A method for preparing electronic grade 1,3-propane sultone comprises the following steps:

[0013] (S1) adding a low boiling point, hydrophobic organic solvent to industrial grade propane sultone for dilution to obtain a propane sultone solution;

[0014] (S2) adding a dehydrating agent and stirring to dehydrate, and performing reduced pressure distillation to remove solvent and acid from the obtained material; the dehydrating agent includes an acyl chloride compound;

[0015] (S3) the obtained substance enters into a deacidification resin for cyclic deacidification treatment to obtain a propane sultone solution having an acidity of less than 50 ppm;

[0016] (S4) The obtained propane sultone solution with low moisture and low acidity is subjected to desolventization and vacuum distillation to obtain electronic grade 1,3-propane sultone with low moisture, low acidity and high content.

[0017] Furthermore, the low boiling point, hydrophobic organic solvent in step (S1) is selected from dichloromethane, chloroform, ether, petroleum ether, cyclohexane, and n-hexane; and the amount of the organic solvent added is 2 to 5 times the mass of propane sultone, preferably 2.5 times.

[0018] Further, in step (S2), the acyl chloride compound is at least one of thionyl chloride, acetyl chloride, chlorosulfonic acid, benzenesulfonyl chloride, and ethyl chloroformate, preferably thionyl chloride. The amount of water removal agent added is 0.8-1.2wt% of the mass of industrial-grade propane sultone. The water removal agent is added slowly, such as slowly dripped, and the addition is completed within 0.5-1h. Note that the acyl chloride substance cannot be oxalyl chloride. On the one hand, oxalyl chloride is more toxic, and on the other hand, it will affect the acid value of the product.

[0019] Furthermore, in step (S2), an oxazoline compound with a mass percentage of 0.3-0.5wt% of propane sultone is also added, and the oxazoline compound is selected from at least one of 2-methyl-2-oxazoline and 2-ethyl-2-oxazoline. The inventor unexpectedly found that the addition of the oxazoline compound can further reduce the water content in the product and improve the yield of the product 1,3-propane sultone, which may be due to the addition of the oxazoline compound allowing a small amount of 1,3-PS hydrolyzate 3-hydroxypropane sulfonic acid to be rapidly lactonized again.

[0020] Furthermore, in step (S2), the dehydration temperature is 30-60°C; the pressure of the vacuum distillation is controlled to be -0.09 to -0.1MPa, the temperature is 40-70°C, and the vacuum distillation is performed until the acidity of the system is less than 300ppm. The purpose of the vacuum distillation is to remove part of the solvent and most of the acidic light components.

[0021] Furthermore, in step (S3), the types of deacidification resins are: strongly basic anion exchange resins, weak basic anion resins, preferably weak basic anion resins; the deacidification resins need to be activated in advance, and the activation steps are solvent washing-water washing-alkali washing-water washing-solvent washing. Deacidification resin activation is well known in the art. There is no particular limitation on the cyclic deacidification temperature and time, such as 20-50°C, and the deacidification time is 1-5h. Reduce the acidity of the system to below 50ppm.

[0022] Furthermore, in step (S4), the desolventizing operation temperature is 50-80°C, and the pressure is -0.09 to -0.1MPa; the vacuum distillation operation temperature is 120-180°C, and the pressure is 5-50Pa.

[0023] Compared with other preparation technologies, the preparation method of electronic grade 1.3-propane sultone of the present invention has the following beneficial effects:

[0024] 1. The present invention adopts an acidic water removing agent, which fundamentally avoids the decomposition of propane sultone to produce sulfur dioxide or sulfur trioxide during high-temperature distillation, thereby ensuring product quality.

[0025] 2. In the preferred technical solution of the present invention, in addition to adding an acidic water removal agent, a small amount of oxazoline compounds is also added to further improve the water removal rate and the product yield.

[0026] 3. The anion exchange resin used in the present invention as a deacidification resin can not only remove the acidic substances produced after water removal, but also remove the acidic substances in the original system (such as unesterified trihydroxypropane sulfonic acid, etc.), thereby ensuring the quality of low-acidity electronic grade 1.3-propane sultone. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The GC chromatogram of electronic grade 1,3-propane sultone obtained as the product in Example 1 is shown in FIG. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described below in conjunction with embodiments, but the present invention is by no means limited to the examples of the present invention.

[0029] The industrial-grade propane sultone used in the present invention has a content of 99.25%, an acidity of 208 ppm, and a moisture content of 907 ppm.

[0030] Example 1

[0031] (S1) In a glove box, 256.4 g of industrial-grade propane sultone was added to a 1000 ml three-necked flask equipped with a magnet and a thermometer, and then added to 638.5 g of dichloromethane having a water content of 28 ppm and stirred and diluted to obtain a propane sultone solution;

[0032] (S2) 2.05 g of thionyl chloride was slowly added dropwise to the propane sultone solution at 30° C. for 0.5 h, and the solution was stirred for 3 h for dehydration. The water content was 26.8 ppm and the acidity was 1930.6 ppm. The solution was transferred to a 1500 ml single-necked flask and transferred to a rotary evaporator under nitrogen positive pressure. The solvent and acid were removed to 432.6 g at 30° C. and -0.095 MPa. The water content and acidity were 19.6 ppm and 225.1 ppm, respectively.

[0033] (S3) The material was transferred to a glove box, and a peristaltic pump was used to pump the material into a container containing Sunlite A220 deacidification resin, and the deacidification was circulated at a material flow rate of 2000 g / h. After 3 hours of circulation, the water content and acidity of the sample were measured to be 18.7 ppm and 15.3 ppm respectively;

[0034] (S4) The deacidified material is transferred to a rotary evaporator under a nitrogen atmosphere, and the remaining solvent is removed at 80° C. and −0.098 MPa. The methylene chloride content in the gas phase is detected to be 0.05%. Then, vacuum distillation is started, the system pressure is controlled to be 30 Pa, the kettle temperature is 150° C., and the fractions at 118 to 125° C. are collected. The distillation is completed after 4 hours to obtain 241.93 g of electronic grade 1,3-propane sultone product with a purity of 99.73%, a moisture content of 18.2 ppm, and an acidity of 16.2 ppm, with a yield of 94.81%.

[0035] Figure 1 This is the GC chromatogram of the electronic grade 1,3-propane sultone obtained in Example 1. The peak with a retention time RT (min) of about 2.4 min is the peak of the methanol solvent, and the GC purity of the product 1,3-PS (retention time = 8.168 min) reaches 99.7%.

[0036] Example 2

[0037] Other conditions and operations were the same as those in Example 1, except that in step (S2), 2.05 g of thionyl chloride was replaced by 3.01 g of chlorosulfonic acid. Finally, 236.2 g of electronic grade 1,3-propane sultone product with a purity of 99.68%, a moisture content of 17.4 ppm, and an acidity of 15.7 ppm was obtained, with a yield of 92.52%.

[0038] Example 3

[0039] Other conditions and operations were the same as those in Example 1, except that 0.77 g of 2-methyl-2-oxazoline was added in step (S2). Finally, 248.4 g of electronic grade 1,3-propane sultone product with a purity of 99.71%, a moisture content of 13.7 ppm, and an acidity of 14.1 ppm was obtained, with a yield of 97.33%.

[0040] Example 4

[0041] Other conditions and operations were the same as those in Example 1, except that 1.28 g of 2-ethyl-2-oxazoline was added in step (S2). Finally, 247.9 g of electronic grade 1,3-propane sultone product with a purity of 99.62%, a moisture content of 13.5 ppm, and an acidity of 14.2 ppm was obtained, with a yield of 97.04%.

[0042] Comparative Example 1

[0043] Other conditions and operations were the same as those in Example 1, except that in step (S2), 2.05 g of thionyl chloride was replaced by 3.30 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, i.e., an equimolar amount of EDC hydrochloride. Finally, 230.6 g of electronic grade 1,3-propane sultone product with a purity of 99.51%, a moisture content of 18.2 ppm, and an acidity of 26.5 ppm was obtained, with a yield of 90.17%.

[0044] Comparative Example 2

[0045] Other conditions and operations were the same as those in Example 1, except that in step (S2), 2.05 g of thionyl chloride was replaced by 20 g of molecular sieve 4A. Finally, 237.9 g of electronic grade 1,3-propane sultone product with a purity of 98.42%, a moisture content of 46.1 ppm, and an acidity of 14.6 ppm was obtained, with a yield of 92.01%.

Claims

1. A method for preparing electronic grade 1,3-propane sultone, characterized in that: The following steps are involved: (S1) adding a low boiling point, hydrophobic organic solvent to industrial grade propane sultone for dilution to obtain a propane sultone solution; (S2) adding a dehydrating agent and stirring to dehydrate, and performing reduced pressure distillation to remove solvent and acid from the obtained material; the dehydrating agent includes an acyl chloride compound; (S3) the obtained substance enters into a deacidification resin for cyclic deacidification treatment to obtain a propane sultone solution having an acidity of less than 50 ppm; (S4) The obtained propane sultone solution with low moisture and low acidity is subjected to desolventization and vacuum distillation to obtain electronic grade 1,3-propane sultone with low moisture, low acidity and high content.

2. The preparation method according to claim 1, characterized in that: The low boiling point, hydrophobic organic solvent in step (S1) is selected from dichloromethane, chloroform, ether, petroleum ether, cyclohexane, and n-hexane.

3. The preparation method according to claim 1, characterized in that: The amount of organic solvent added is 2 to 5 times the mass of propane sultone.

4. The preparation method according to claim 1, characterized in that: In step (S2), the acyl chloride compound is at least one of thionyl chloride, acetyl chloride, chlorosulfonic acid, benzenesulfonyl chloride, and ethyl chloroformate, preferably thionyl chloride.

5. The preparation method according to claim 1, characterized in that: In step (S2), the amount of water removal agent added is 0.8-1.2 wt % of the mass of industrial-grade propane sultone.

6. The preparation method according to claim 1, characterized in that: In step (S2), the dehydrating agent is added slowly and the addition is completed within 0.5-1 hour.

7. The preparation method according to claim 1, characterized in that: In step (S2), an oxazoline compound in an amount of 0.3-0.5 wt % of the mass of propane sultone is further added, wherein the oxazoline compound is selected from at least one of 2-methyl-2-oxazoline and 2-ethyl-2-oxazoline.

8. The preparation method according to claim 1, characterized in that: In step (S2), the dehydration temperature is 30-60°C; the pressure of the vacuum distillation is controlled to be -0.09 to -0.1 MPa, the temperature is 40-70°C, and the vacuum distillation is carried out until the acidity of the system is less than 300 ppm.

9. The preparation method according to claim 1, characterized in that: The types of deacidification resins are: strongly basic anion exchange resins and weakly basic anion resins, with weakly basic anion resins being preferred.

10. The preparation method according to claim 1, characterized in that: In step (S4), the desolventizing operation temperature is 50-80°C and the pressure is -0.09 to -0.1MPa; the vacuum distillation operation temperature is 120-180°C and the pressure is 5-50Pa.

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