Preparation method of trimethylolpropane phosphate

Abstract

The invention provides a preparation method of trimethylolpropane phosphate, which comprises the following steps: uniformly mixing and stirring trimethylolpropane and dichloromethane, then dropwise adding phosphorus oxychloride, and carrying out heat preservation in a normal-pressure non-closed system to obtain a reaction solution; purging the reaction liquid with nitrogen, and then concentrating the reaction liquid under a vacuum condition to obtain viscous liquid; adding the viscous liquid into an ester solvent, dissolving and stirring, and then separating the liquid to remove viscous impurities, so as to obtain a trimethylolpropane phosphate solution; and then carrying out vacuum concentration to obtain the trimethylolpropane phosphate. According to the method, high-purity trimethylolpropane phosphate is efficiently synthesized in a high-yield manner under a mild condition, and the method is suitable for industrial production and has very high practicability.

Description

Technical Field

[0001] The present application relates to the field of chemical technology, and in particular to a method for preparing trimethylolpropane phosphate. Background Art

[0002] Trimethylolpropane phosphate has a certain reducibility and can be used as an electrolyte additive to form a passivated interface film on the positive electrode surface, blocking the direct contact between the electrolyte and the positive electrode surface, inhibiting the oxidative decomposition of the electrolyte components on the positive electrode surface under charging, and helping to improve the high voltage performance of the battery. At the same time, as a phosphorus-containing compound, trimethylolpropane phosphate can reduce the flammability of the electrolyte and improve the safety of the battery. Its flame retardant mechanism is the annihilation of gas-phase free radicals and thermal barrier mechanism. When the temperature is high, the flame retardant molecules in the electrolyte are vaporized to generate phosphorus-containing free radicals, which capture the oxygen free radicals and hydroxyl free radicals generated by the solvent in the electrolyte to generate phosphoric acid, and finally form a thermal retardation layer, which covers the surface of the electrolyte, thereby preventing the combustion of the electrolyte. In the prior art, the synthesis method of trimethylolpropane phosphate requires strict control of process conditions, a long reaction time, or requires hot water treatment, which is easy to have an adverse effect on the application of trimethylolpropane phosphate in the electrolyte; or after treatment with sodium hydroxide aqueous solution and then extraction with dichloromethane, the process is complicated. Summary of the invention

[0003] The purpose of this application is to provide a method for preparing trimethylolpropane phosphate, so as to synthesize high-purity trimethylolpropane phosphate efficiently and in high yield under mild conditions. The specific technical scheme is as follows:

[0004] The present application provides a method for preparing trimethylolpropane phosphate, comprising the following steps:

[0005] (a) mixing trimethylolpropane and dichloromethane and stirring them uniformly; adding phosphorus oxychloride dropwise at a reaction temperature of 10-35° C., and keeping the temperature in a non-sealed system at normal pressure for 3-6 hours to obtain a reaction solution;

[0006] (b) purging the reaction solution with nitrogen for 0.5-6 hours, and after the purging is completed, concentrating the reaction solution to a viscous state under a vacuum condition of 30-60° C. and −0.1 MPa to 0.09 MPa to obtain a viscous liquid;

[0007] (c) adding an ester solvent to the viscous liquid to dissolve trimethylolpropane phosphate, stirring at room temperature for 1-3 hours, and then separating the liquid to remove viscous impurities to obtain a trimethylolpropane phosphate solution;

[0008] (d) concentrating the trimethylolpropane phosphate solution under vacuum to remove the solvent to obtain trimethylolpropane phosphate;

[0009] Wherein, the ester solvent is selected from at least one of dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethyl acetate, ethyl propionate, ethylene carbonate and propylene carbonate.

[0010] In the method of the present application, by mixing trimethylolpropane with a solvent of dichloromethane and then dropping phosphorus oxychloride, the reaction can be carried out under relatively mild process conditions, and the reactants are easily separated and purified. After the reaction, the reaction product is concentrated and purified with an ester solvent, and the product trimethylolpropane phosphate is easily dissolved in the ester solvent, thereby removing impurities. The obtained trimethylolpropane phosphate has high purity and will not have adverse effects on the electrolyte.

[0011] In some embodiments of the present application, the molar ratio of trimethylolpropane to phosphorus oxychloride in step (a) is 1:0.95-1:1.2. By controlling the molar ratio of trimethylolpropane to phosphorus oxychloride within this range, at least one of the reactants can be reacted completely with relatively less impurities.

[0012] In some embodiments of the present application, the mass ratio of trimethylolpropane to dichloromethane in step (a) is 1: 1-1: 7. By controlling the content of the solvent dichloromethane within this range, the reaction rate and the viscosity of the product can be controlled, so that the reaction is carried out under mild conditions and the product is easier to separate.

[0013] In some embodiments of the present application, the pressure of the nitrogen purge in step (b) is maintained at 0.005-0.1 bar.

[0014] In some embodiments of the present application, the concentration time in step (b) is 1-6 hours.

[0015] In some embodiments of the present application, the amount of the ester solvent added in step (c) is 5-10 times, preferably 6-8 times, the mass of the viscous liquid in step (b). By controlling the ratio of the amount of the ester solvent added to the viscous liquid within this range, the product trimethylolpropane phosphate can be more fully dissolved, thereby improving the yield and purity.

[0016] In some embodiments of the present application, the vacuum concentration in step (d) is performed at a temperature of 80-110°C.

[0017] Beneficial effects of this application:

[0018] The present application provides a method for preparing trimethylolpropane phosphate, wherein trimethylolpropane and phosphorus oxychloride are used as raw materials to prepare trimethylolpropane phosphate under mild conditions, and high-purity trimethylolpropane phosphate is obtained through nitrogen purging, deacidification, concentration, liquid separation and other processes. The reaction conditions are mild, the process is simple, the reaction time is short, and the product yield is high.

[0019] Of course, implementing any product or method of the present application does not necessarily require achieving all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application, and a person skilled in the art can also obtain other embodiments based on these drawings.

[0021] Figure 1 is the standard spectrum of trimethylolpropane phosphate in the mass spectrum library;

[0022] Figure 2 is the mass spectrum of trimethylolpropane phosphate obtained in Example 1 of the present application;

[0023] Figure 3 This is a comparison chart of the mass spectrum of trimethylolpropane phosphate obtained in Example 1 of the present application and the standard spectrum of trimethylolpropane phosphate;

[0024] Figure 4 is the mass spectrum of trimethylolpropane phosphate obtained in Example 2 of the present application;

[0025] Figure 5 This is a comparison chart of the mass spectrum of trimethylolpropane phosphate obtained in Example 2 of the present application and the standard spectrum of trimethylolpropane phosphate;

[0026] Figure 6 is the mass spectrum of trimethylolpropane phosphate obtained in Example 3 of the present application;

[0027] Figure 7 This is a comparison chart of the mass spectrum of trimethylolpropane phosphate obtained in Example 3 of the present application and the standard spectrum of trimethylolpropane phosphate;

[0028] Figure 8 is the mass spectrum of trimethylolpropane phosphate obtained in Example 4 of the present application;

[0029] Fig. 9 This is a comparison chart of the mass spectrum of trimethylolpropane phosphate obtained in Example 4 of the present application and the standard spectrum of trimethylolpropane phosphate;

[0030] Fig.10 is the mass spectrum of trimethylolpropane phosphate obtained in Example 5 of the present application;

[0031] Fig.11 This is a comparison chart of the mass spectrum of trimethylolpropane phosphate obtained in Example 5 of the present application and the standard spectrum of trimethylolpropane phosphate;

[0032] Fig.12 is the mass spectrum of trimethylolpropane phosphate obtained in Example 6 of the present application;

[0033] Fig.13 is a comparison chart of the mass spectrum of trimethylolpropane phosphate obtained in Example 6 of the present application and the standard spectrum of trimethylolpropane phosphate;

[0034] Fig.14 is the mass spectrum of trimethylolpropane phosphate obtained in Example 7 of the present application;

[0035] Fig.15 is the mass spectrum of trimethylolpropane phosphate obtained in Example 8 of the present application;

[0036] Fig.16 is a comparison chart of the mass spectrum of trimethylolpropane phosphate obtained in Example 8 of the present application and the standard spectrum of trimethylolpropane phosphate;

[0037] Fig.17 is the mass spectrum of trimethylolpropane phosphate obtained in Example 9 of the present application;

[0038] Fig.18 is a mass spectrum of trimethylolpropane phosphate obtained in Example 10 of the present application;

[0039] Fig.19 is a comparison chart of the mass spectrum of trimethylolpropane phosphate obtained in Example 10 of the present application and the standard spectrum of trimethylolpropane phosphate;

[0040] Fig. 20 is the mass spectrum of trimethylolpropane phosphate obtained in Example 11 of the present application;

[0041] Fig.21 is a comparison chart of the mass spectrum of trimethylolpropane phosphate obtained in Example 11 of the present application and the standard spectrum of trimethylolpropane phosphate;

[0042] Fig. 22 is the mass spectrum of trimethylolpropane phosphate obtained in Example 12 of the present application;

[0043] Fig.23 is a comparison chart of the mass spectrum of trimethylolpropane phosphate obtained in Example 12 of the present application and the standard spectrum of trimethylolpropane phosphate;

[0044] Fig.24 is the mass spectrum of trimethylolpropane phosphate obtained in Example 13 of the present application;

[0045] Fig.25is a comparison chart of the mass spectrum of trimethylolpropane phosphate obtained in Example 13 of the present application and the standard spectrum of trimethylolpropane phosphate;

[0046] Fig.26 is a mass spectrum of trimethylolpropane phosphate obtained in Example 14 of the present application;

[0047] Fig. 27 This is a comparison chart of the mass spectrum of trimethylolpropane phosphate obtained in Example 14 of the present application and the standard spectrum of trimethylolpropane phosphate. DETAILED DESCRIPTION

[0048] The following will be combined with the embodiments of the present application to clearly and completely describe the technical solutions in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those skilled in the art based on the present application belong to the scope of protection of the present application.

[0049] The present application provides a method for preparing trimethylolpropane phosphate, comprising the following steps:

[0050] (a) mixing trimethylolpropane and dichloromethane and stirring them uniformly; adding phosphorus oxychloride dropwise at a reaction temperature of 10-35° C., and keeping the temperature in a non-sealed system at normal pressure for 3-6 hours to obtain a reaction solution;

[0051] (b) purging the reaction solution with nitrogen for 0.5-6 hours, and after the purging is completed, concentrating the reaction solution to a viscous state under a vacuum condition of 30-60° C. and −0.1 MPa to 0.09 MPa to obtain a viscous liquid;

[0052] (c) adding an ester solvent to the viscous liquid to dissolve trimethylolpropane phosphate, stirring at room temperature for 1-3 hours, and then separating the liquid to remove viscous impurities to obtain a trimethylolpropane phosphate solution;

[0053] (d) concentrating the trimethylolpropane phosphate solution under vacuum to remove the solvent to obtain trimethylolpropane phosphate;

[0054] Wherein, the ester solvent is selected from at least one of dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethyl acetate, ethyl propionate, ethylene carbonate and propylene carbonate.

[0055] Mixing trimethylolpropane with the reaction solvent dichloromethane can control the reaction speed so that the reaction is carried out under mild conditions. After the reaction, the trimethylolpropane phosphate is dissolved with an ester solvent after concentration, and then the ester solvent is removed to obtain high-purity trimethylolpropane phosphate. The inventor found in the study that the oligomer impurities in the viscous liquid are not ester substances, and the product trimethylolpropane phosphate is an ester. By the principle of similar dissolving, ester compounds are selected to dissolve trimethylolpropane phosphate. The oligomer impurities can be separated from trimethylolpropane phosphate by liquid separation. Further, the trimethylolpropane phosphate solution is vacuum concentrated to remove the solvent to obtain high-purity trimethylolpropane phosphate. Compared with the traditional preparation method, the reaction of the present application is carried out under mild conditions, and the reaction time can be shortened, which not only reduces energy consumption, but also reduces production costs.

[0056] In some embodiments of the present application, the molar ratio of trimethylolpropane to phosphorus oxychloride in step (a) is 1:0.95-1:1.2. The inventors have found in their research that the molar ratio of trimethylolpropane to phosphorus oxychloride is limited to the above range, which can increase the yield of trimethylolpropane phosphate.

[0057] In some embodiments of the present application, the mass ratio of trimethylolpropane to dichloromethane in step (a) is 1:1-1:7. The inventors found in their research that the mass percentage of trimethylolpropane to dichloromethane is limited to the above range, the reaction rate is moderate, and the reaction conditions are mild. If there is no solvent reaction, the reaction is very violent, and the reaction solution is very viscous and cannot be sampled for detection; adding a suitable amount of solvent will increase the yield of the reaction, and further increasing the amount of solvent will not increase the reaction yield, but will cause waste.

[0058] In some embodiments of the present application, the pressure of the nitrogen purge in step (b) is maintained at 0.005-0.1 bar. Controlling the nitrogen purge pressure within the above range can remove the reaction product, hydrogen chloride, and ensure the smooth progress of the reaction.

[0059] In some embodiments of the present application, the concentration time in step (b) is 1-6 hours. For example, the concentration time can be 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours or a range consisting of any two of the values. The inventors found in the study that as the concentration time increases, the chloride ion content and acidity of the viscous liquid decrease, with a significant decrease in the first 4 hours, and a slower decrease after 4 hours, until 6 hours, the chloride ion content and acidity of the viscous liquid tend to be stable.

[0060] In some embodiments of the present application, the amount of the ester solvent added in step (c) is 5-10 times, preferably 6-8 times, the mass of the viscous liquid in step (b). The inventors found in their research that the purity of trimethylolpropane phosphate can be effectively improved when the amount of ester solvent added is within the above range. If the amount of ester solvent added is too small, part of the product will remain in the oligomer, resulting in a low yield; if too much ester solvent is added, a small amount of impurities may dissolve in the ester solvent and mix with the product to affect the purity of the product.

[0061] In some embodiments of the present application, the vacuum concentration in step (d) is performed at a temperature of 80-110° C. The inventors have found in their research that limiting the vacuum concentration temperature within the above range can improve the concentration efficiency, and if the concentration temperature is too low, the ester solvent cannot be removed and the concentration time is prolonged, and if the concentration temperature is too high, the structure of trimethylolpropane phosphate will be affected.

[0062] Unless otherwise specified, the reagents, materials and instruments used in this application are commercially available.

[0063] Example

[0064] The following examples are given to more specifically describe the embodiments of the present application. Various tests and evaluations were performed according to the following methods. In addition, unless otherwise specified, "parts" are based on mass.

[0065] Test methods and equipment:

[0066] <Trimethylolpropane phosphate yield>

[0067] The content of the trimethylolpropane phosphate sample was tested using a gas chromatograph (model: Agilent 8890-7000D) using a single-point external standard method; the mass of the trimethylolpropane phosphate product obtained in the test step (d) was recorded as W1; the theoretical mass of the trimethylolpropane phosphate produced could be calculated based on the amount of phosphorus oxychloride added, recorded as W0.

[0068] Yield = (sample content × W1) / W0 × 100%.

[0069] GC sample treatment: Take 0.50 g (accurate to 0.0002 g) of sample and dissolve it in an appropriate amount of acetonitrile, transfer it to a 50 mL volumetric flask and dilute to the scale, sonicate, shake well, filter with a 0.45 μm organic filter head, and prepare for GC testing.

[0070] GC test conditions: Chromatographic column: J&W HP-5ms, 60m×0.25mm×0.25μm; injection volume is 1.0μL; injection port temperature is 300℃; detector temperature is 320℃; chromatographic column heating program: 100℃ for 3min, heating rate is 15℃ / min, chromatographic column final temperature is 300℃, hold for 5min; split ratio is (50:1); column flow rate is 1.0ml / min.

[0071] <Trimethylolpropane phosphate purity>

[0072] The purity of the product was detected by the area normalization method, and the arithmetic mean of all the integrals of all GC peaks was taken as the determination result.

[0073] <Trimethylolpropane phosphate determination>

[0074] The determination was made by comparing the mass spectrum of the sample with the standard spectrum of MS Curry trimethylolpropane phosphate.

[0075] GC-MS sample treatment: Take 0.50 g (accurate to 0.0002 g) of sample and dissolve it in an appropriate amount of acetonitrile, transfer it to a 50 mL volumetric flask and dilute to the scale, sonicate, shake well, filter with a 0.45 μm organic filter head, and prepare for GC-MS testing.

[0076] GC-MS test conditions: chromatographic column: J&W HP-5ms, 60m×0.25mm×0.25μm; injection volume, 0.5μL; injection port temperature, 300℃; detector temperature, 320℃; chromatographic column heating program: 100℃ for 3min, heating rate, 15℃ / min, chromatographic column final temperature, 300℃, for 5min; split ratio, (100:1); column flow rate, 1.0mL / min.

[0077] Example 1

[0078] 26.83 g of trimethylolpropane (TMP) and 80.49 g of dichloromethane were added to a three-necked flask equipped with a thermometer and an electric stirrer, and the mixture was stirred uniformly; 33.73 g of phosphorus oxychloride (PO) was added dropwise at a reaction temperature of 20° C., and the mixture was kept warm for 4.5 h in a non-sealed system at normal pressure to obtain a light yellow reaction liquid; the reaction liquid was purged with nitrogen for 0.5 h, and the pressure was maintained at 0.05 bar. After the purging was completed, the reaction liquid was concentrated under vacuum conditions of 45° C. and -0.1 MPa for 1 h to obtain a viscous liquid; further, 7 times the mass of dimethyl carbonate was added to the viscous liquid, and the mixture was stirred at room temperature for 2 h, and then the viscous impurities were separated to obtain a trimethylolpropane phosphate solution; the trimethylolpropane phosphate solution was placed in a vacuum drying oven at a temperature of 95° C. until it stopped losing weight, and the obtained sample was determined to be trimethylolpropane phosphate by GC-MS analysis method, with a purity of 100% and a yield of about 50%. GC-MS characterization see Figure 2 and Figure 3 .

[0079] Example 2-14

[0080] Except for adjusting the dosage of TMP and PO according to Table 1; adjusting the type and dosage of the ester solvent; adjusting the reaction time and the stirring time of the ester solvent, the rest is the same as Example 1. The purity and yield of the obtained trimethylolpropane phosphate are shown in Table 1. GC-MS characterization is shown in Figures 4 to 27 .

[0081] Table 1

[0082]

[0083] As can be seen from the above examples, the preparation method of the present application can be completed at room temperature and pressure by selecting a reasonable raw material ratio and a suitable solvent dosage, and a high-yield trimethylolpropane phosphate reaction liquid is obtained, which not only simplifies the process flow, but also reduces production costs; at the same time, an ester compound is selected to dissolve trimethylolpropane phosphate, and oligomer impurities are separated from trimethylolpropane phosphate by liquid separation. Further, the trimethylolpropane phosphate solution is vacuum concentrated, and the solvent is removed to obtain high-purity trimethylolpropane phosphate, which greatly improves production efficiency. In addition, the preparation method of the present application is simple to operate, has a short reaction time, reduces energy consumption, and further reduces production costs.

[0084] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A method for preparing trimethylolpropane phosphate, comprising the following steps: (a) mixing trimethylolpropane and dichloromethane and stirring them uniformly; adding phosphorus oxychloride dropwise at a reaction temperature of 10-35° C., and keeping the temperature in a non-sealed system at normal pressure for 3-6 hours to obtain a reaction solution; (b) purging the reaction solution with nitrogen for 0.5-6 hours, and after the purging is completed, concentrating the reaction solution to a viscous state under a vacuum condition of 30-60° C. and −0.1 MPa to 0.09 MPa to obtain a viscous liquid; (c) adding an ester solvent to the viscous liquid to dissolve trimethylolpropane phosphate, stirring at room temperature for 1-3 hours, and then separating the liquid to remove viscous impurities to obtain a trimethylolpropane phosphate solution; (d) concentrating the trimethylolpropane phosphate solution under vacuum to remove the solvent to obtain trimethylolpropane phosphate; Wherein, the ester solvent is at least one selected from dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethyl acetate, ethyl propionate, ethylene carbonate and propylene carbonate.

2. The preparation method according to claim 1, wherein In step (a), the molar ratio of trimethylolpropane to phosphorus oxychloride is 1:0.95-1:1.

2.

3. The preparation method according to claim 1, wherein In step (a), the mass ratio of trimethylolpropane to dichloromethane is 1:1-1:

7.

4. The preparation method according to claim 1, wherein The pressure of the nitrogen purge in step (b) is maintained at 0.005-0.1 bar.

5. The preparation method according to claim 1, wherein The concentration time in step (b) is 1-6 hours.

6. The preparation method according to claim 1, wherein In step (c), the amount of the ester solvent added is 5-10 times the mass of the viscous liquid.

7. The preparation method according to claim 1, wherein In step (c), the amount of the ester solvent added is 6-8 times the mass of the viscous liquid.

8. The preparation method according to claim 1, wherein The vacuum concentration in step (d) is carried out at a temperature of 80-110°C.

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