Phosphate as well as preparation method and application thereof

Abstract

The invention discloses phosphate as well as a preparation method and application thereof, and belongs to the technical field of chemical processes. The preparation method comprises the following steps: (1) esterification reaction: carrying out esterification reaction on an organic alcohol compound and phosphorus pentoxide to obtain a phosphate intermediate; and (2) alcoholysis reaction: adding C1-C8 monohydric alcohol into the phosphate intermediate, and performing alcoholysis on the polyphosphate in the phosphate intermediate to obtain the phosphate. According to the phosphate prepared by the method, a phosphate product with low free phosphoric acid content can be obtained without purification, the process stability is good, and the product can be used as an additive in the battery industry and the like and has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the field of chemical process technology, and in particular to a phosphate ester and a preparation method and application thereof. Background Art

[0002] As a commonly used battery external additive, phosphate ester can improve the viscosity of electrode slurry, thereby improving battery processing performance such as electrode peel strength and flexibility, and can be used to ensure battery point density.

[0003] However, in conventional technology, phosphate ester products using phosphorus pentoxide as a phosphorus source often contain a large amount of free phosphoric acid, which may precipitate when used in battery slurry, resulting in a decrease in the electrical performance of the electrode. Summary of the invention

[0004] In view of the problem that the phosphate ester product using phosphorus pentoxide as the phosphorus source in the above conventional technology has a high free phosphoric acid content, the present invention provides a method for preparing phosphate ester. By using the method to prepare the phosphate ester product, the content of free phosphoric acid therein can be reduced, and the phosphate ester product can be directly used in subsequent processes without purification.

[0005] In one aspect, the present invention provides a method for preparing a phosphate ester, comprising the following steps:

[0006] (1) Esterification reaction: Esterification reaction of organic alcohol compounds with phosphorus pentoxide to obtain phosphate intermediates;

[0007] (2) Alcoholysis reaction: Add C 1- C8 monohydric alcohol is used to alcoholize the polyphosphate in the phosphate intermediate to obtain the phosphate.

[0008] In some embodiments, the organic alcohol compound is selected from at least one of fatty alcohols and terminal hydroxyl polymers; preferably, the terminal hydroxyl polymer.

[0009] In some embodiments, the terminal hydroxyl polymer is selected from at least one of alkoxy polyethylene glycol, alkoxy polypropylene glycol, random or block polyether of alkoxy polyethylene glycol polypropylene glycol, polyether diol, polyether polyol, and polytetrahydrofuran; the alkoxy group in the terminal hydroxyl polymer is a normal alkyl group with 1 to 18 carbon atoms or its isomers.

[0010] In some embodiments, the terminal hydroxyl polymer is selected from at least one of polyethylene glycol, polypropylene glycol, butanol-terminated polyoxyethylene-polyoxypropylene random mixed polyether, glycerol ether, and polytetrahydrofuran.

[0011] In some embodiments, the C 1-The C8 monohydric alcohol is selected from at least one of methanol, ethanol, n-propanol, isopropanol, butanol, isobutanol, tert-butanol, n-pentanol and its isomeric alcohols, n-hexanol and its isomeric alcohols, n-heptanol and its isomeric alcohols, and n-octanol and its isomeric alcohols.

[0012] In some embodiments, the C 1- The C8 monohydric alcohol is selected from at least one of n-propanol, n-butanol, isopropanol, isobutanol, methanol and ethanol.

[0013] In some embodiments, the organic alcohol compound is a hydroxyl-terminated polymer, and the weight average molecular weight of the hydroxyl-terminated polymer is 200-5000, preferably 1000-3000, for example, 1000, 1500, 2000, 3000.

[0014] In some embodiments, the water content of the organic alcohol compound is less than 2000 ppm; further, the water content of the organic alcohol compound is less than 1600 ppm, less than 1100 ppm, less than 800 ppm, less than 600 ppm, or less than 400 ppm.

[0015] In some embodiments, in the esterification reaction, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.0-3.0:1, preferably 2.2-2.7:1, for example: 2.2:1, 2.3:1, 2.5:1, 2.6:1, 2.7:1.

[0016] In some embodiments, in the alcoholysis reaction, the C 1- The addition amount of C8 monohydric alcohol is 0.5-5 wt% of the phosphate intermediate, preferably 1-2 wt%, for example: 1.5 wt%.

[0017] In some embodiments, in the esterification reaction, the phosphorus pentoxide is added when the temperature of the organic alcohol compound is controlled to be 10-80°C; preferably, the phosphorus pentoxide is added when the temperature of the organic alcohol compound is 20°C-80°C, for example, 20°C, 40°C, 50°C, 60°C, or 80°C.

[0018] In some embodiments, in the esterification reaction, the temperature of the esterification reaction is 50-110°C; preferably, the temperature of the esterification reaction is 65-95°C, for example: 65°C, 80°C, 85°C, 90°C, 95°C.

[0019] In some embodiments, in the esterification reaction, the esterification reaction time is 1-10 h; preferably, the esterification reaction time is 4-10 h, for example: 4 h, 5 h, 6 h, 8 h, 10 h.

[0020] In some embodiments, in the alcoholysis reaction, the temperature of the alcoholysis reaction is 85-115°C; preferably, the temperature of the alcoholysis reaction is 85-115°C, for example: 85°C, 95°C, 100°C, 105°C, 115°C.

[0021] In some embodiments, in the alcoholysis reaction, the alcoholysis reaction time is 0.5-10 h; preferably, the esterification reaction time is 0.5-4 h, for example: 0.5 h, 1 h, 2 h, 4 h.

[0022] In some embodiments, the organic alcohol compound is polyethylene glycol with a number average molecular weight of 800-1200, and the C 1- The C8 monohydric alcohol is propanol, the water content of the organic alcohol compound is ≤1000 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.2-3.0:1, in the esterification reaction, the feeding temperature is 10-30°C, the reaction temperature is 70-90°C, and the reaction time is 4-6 h, and in the alcoholysis reaction, the reaction temperature is 90-110°C, and the reaction time is 0.5-1.5 h.

[0023] In some embodiments, the organic alcohol compound is polyethylene glycol with a number average molecular weight of 1000, and the C 1- The C8 monohydric alcohol is n-propanol, the water content of the organic alcohol compound is ≤800 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.6:1, in the esterification reaction, the feeding temperature is 20°C, the reaction temperature is 80°C, and the reaction time is 5 h, and in the alcoholysis reaction, the reaction temperature is 100°C and the reaction time is 1 h.

[0024] In some embodiments, the organic alcohol compound is polypropylene glycol with a number average molecular weight of 1200-1800, and the C 1- The C8 monohydric alcohol is butanol, the water content of the organic alcohol compound is ≤1300 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.1-2.5:1, in the esterification reaction, the feeding temperature is 50-70°C, the reaction temperature is 80-100°C, and the reaction time is 7-9 h, and in the alcoholysis reaction, the reaction temperature is 85-105°C, and the reaction time is 1-3 h.

[0025] In some embodiments, the organic alcohol compound is polypropylene glycol with a number average molecular weight of 1500, and the C 1-The C8 monohydric alcohol is n-butanol, the water content of the organic alcohol compound is ≤1100 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.3:1, in the esterification reaction, the feeding temperature is 60°C, the reaction temperature is 90°C, and the reaction time is 8 h, and in the alcoholysis reaction, the reaction temperature is 95°C and the reaction time is 2 h.

[0026] In some embodiments, the organic alcohol compound is a butanol-terminated polyoxyethylene-polyoxypropylene random mixed polyether with a number average molecular weight of 800-1200, and the C 1- The C8 monohydric alcohol is propanol, the water content of the organic alcohol compound is ≤1000 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.5-2.9:1, the feeding temperature in the esterification reaction is 10-30°C, the reaction temperature in the esterification reaction is 55-75°C, and the reaction time is 3-5h, and the reaction temperature in the alcoholysis reaction is 105-115°C, and the reaction time is 0.5-1.5 h.

[0027] In some embodiments, the organic alcohol compound is a butanol-terminated polyoxyethylene-polyoxypropylene random mixed polyether with a number average molecular weight of 1000, and the C 1- The C8 monohydric alcohol is isopropanol, the water content of the organic alcohol compound is ≤800 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.7:1, the feeding temperature in the esterification reaction is 20°C, the reaction temperature in the esterification reaction is 65°C and the reaction time is 4 h, and the reaction temperature in the alcoholysis reaction is 115°C and the reaction time is 1 h.

[0028] In some embodiments, the organic alcohol compound is a glycerol ether having a number average molecular weight of 2500-3500, and the C 1- The C8 monohydric alcohol is butanol, the water content of the organic alcohol compound is ≤1800 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.0-2.4:1, in the esterification reaction, the feeding temperature is 40-60°C, the reaction temperature is 75-95°C, and the reaction time is 9-10 h, and in the alcoholysis reaction, the reaction temperature is 95-115°C, and the reaction time is 3-5 h.

[0029] In some embodiments, the organic alcohol compound is a glycerol ether with a number average molecular weight of 3000, 1-The C8 monohydric alcohol is isobutyl alcohol, the water content of the organic alcohol compound is ≤1600 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.2:1, in the esterification reaction, the feeding temperature is 50°C, the reaction temperature is 85°C, and the reaction time is 10 h, and in the alcoholysis reaction, the reaction temperature is 105°C and the reaction time is 4 h.

[0030] In some embodiments, the organic alcohol compound is polytetrahydrofuran having a number average molecular weight of 800-1200, and the C 1- The C8 monohydric alcohol is methanol, the water content of the organic alcohol compound is ≤800 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.5-2.9:1, the feeding temperature in the esterification reaction is 70-90°C, the reaction temperature in the esterification reaction is 75-95°C and the reaction time is 4-5-7 h, and the reaction temperature in the alcoholysis reaction is 75-95°C and the reaction time is 1-3 h.

[0031] In some embodiments, the organic alcohol compound is polytetrahydrofuran with a number average molecular weight of 1000, and the C 1- The C8 monohydric alcohol is methanol, the water content of the organic alcohol compound is ≤600 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.7:1, the feeding temperature in the esterification reaction is 80°C, the reaction temperature in the esterification reaction is 85°C and the reaction time is 6 h, and the reaction temperature in the alcoholysis reaction is 85°C and the reaction time is 2 h.

[0032] In some embodiments, the organic alcohol compound is a butanol-terminated polyoxyethylene-polyoxypropylene random mixed polyether with a number average molecular weight of 1800-2200, and the C 1- The C8 monohydric alcohol is ethanol, the water content of the organic alcohol compound is ≤600 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.3-2.7:1, the feeding temperature in the esterification reaction is 30-50°C, the reaction temperature in the esterification reaction is 85-105°C, and the reaction time is 5-7 h, and the reaction temperature in the alcoholysis reaction is 85-105°C, and the reaction time is 0.5-1 h.

[0033] In some embodiments, the organic alcohol compound is a butanol-terminated polyoxyethylene-polyoxypropylene random mixed polyether with a number average molecular weight of 2000, and the C 1-The C8 monohydric alcohol is ethanol, the water content of the organic alcohol compound is ≤400ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.5:1, the feeding temperature in the esterification reaction is 40°C, the reaction temperature in the esterification reaction is 95°C and the reaction time is 6 h, and the reaction temperature in the alcoholysis reaction is 95°C and the reaction time is 0.5 h.

[0034] In some embodiments, the molar content of free phosphoric acid in the phosphate ester is less than 1.0%; preferably, the molar content of free phosphoric acid in the phosphate ester is less than 0.5%, for example: less than 0.2%, less than 0.1%, less than 0.05%, less than 0.01%.

[0035] On the other hand, the present invention also discloses the phosphate ester prepared by the above-mentioned phosphate ester preparation method.

[0036] On the other hand, the present invention also discloses the use of the above-mentioned phosphate ester as an additive in a positive electrode slurry of a lithium battery.

[0037] In some embodiments, the positive electrode slurry is selected from at least one of lithium iron phosphate slurry and lithium iron manganese phosphate slurry.

[0038] The term "hydroxyl-terminated polymer" refers to an oligomer having a hydroxyl functional group at one or both ends of the molecular chain.

[0039] The term "alkoxy polyethylene glycol" refers to polyethylene glycol terminated with various alkoxy groups.

[0040] The term "alkoxy polypropylene glycol" refers to polypropylene glycol terminated with various alkoxy groups.

[0041] The term "random or block polyethers of alkoxy polyethylene glycol and polypropylene glycol" refers to mixed polymers of polyethylene glycol and polypropylene glycol terminated with different alkoxy groups in different ratios.

[0042] The term "isomerized alcohol" refers to monohydric substituted alcohols having isomeric alkyl chains.

[0043] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0044] The reagents and raw materials used in the present invention are commercially available.

[0045] The positive and progressive effects of the present invention are:

[0046] The present invention provides a method for preparing a phosphate ester, wherein a terminal hydroxyl polymer is reacted with phosphorus pentoxide to obtain a phosphate ester intermediate including a mixture of a phosphate monoester, a phosphate diester and a polyphosphate ester, and then reacted with C 1-8The monohydric alcohol undergoes alcoholysis reaction, so that the polyphosphate ester therein is alcoholysed to obtain a phosphate ester product.

[0047] The above preparation method can obtain a phosphate ester product with a low free phosphoric acid content without purification, and has the advantage of good process stability. The obtained phosphate ester product can be used as an additive in industries such as batteries and has broad application prospects. DETAILED DESCRIPTION

[0048] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0049] In the following examples, the detection of free phosphoric acid in the phosphate ester products was carried out according to the "Phosphoric Acid Content" method under Item 6.6 of QB∕T 2949-2008 "Phosphoric Acid Esters".

[0050] The water content of the raw materials in the following examples was detected according to the following method: Determination was made according to the "direct titration method (visual or coulometric method)" under item 6.1 of GB / T 6283-2008 "Determination of water content in chemical products - Karl Fischer method (general method)".

[0051] Mn: weight average molecular weight.

[0052] Polyethylene glycol (Mn: 1000) with a water content of 800 ppm was purchased from Shanghai Titan Technology Co., Ltd.

[0053] Polypropylene glycol (Mn: 1500) with a water content of 1100 ppm was purchased from Shanghai Titan Technology Co., Ltd.

[0054] Butanol-terminated polyoxyethylene-polyoxypropylene random mixed polyether B11 / 30 (Mn: 1000) with a water content of 800 ppm was purchased from Klein Chemical.

[0055] Glycerol ether (Mn: 3000) with a water content of 1600 ppm was purchased from Hai'an Petrochemical Plant, Jiangsu Province.

[0056] Polytetrahydrofuran (Mn: 1000) with a water content of 600 ppm was purchased from Shanghai Titan Technology Co., Ltd.

[0057] Butanol-terminated polyoxyethylene-polyoxypropylene random mixed polyether B11 / 70 (Mn: 2000) with a water content of 400 ppm was purchased from: Klein Chemical.

[0058] Polypropylene glycol (Mn: 1500) with a water content of 3000 ppm was purchased from Shanghai Titan Technology Co., Ltd.

[0059] Glycerol ether (Mn: 3000) with a water content of 2200 ppm was purchased from Shanghai Titan Technology Co., Ltd.

[0060] Polyethylene glycol (Mn: 600) with a water content of 1200 ppm was purchased from Shanghai Titan Technology Co., Ltd.

[0061] Butanol-terminated polyoxyethylene-polyoxypropylene random mixed polyether B11 / 100 (Mn: 1800) with a water content of 2300 ppm was purchased from Clariant Chemicals.

[0062] Example 1

[0063] A phosphate ester is prepared by the following method.

[0064] (1) Esterification reaction: Add phosphorus pentoxide to polyethylene glycol (Mn: 1000) with a water content of 800 ppm at 20°C. The ratio of the molar number of hydroxyl groups in the raw material to the molar number of phosphorus pentoxide is 2.6:1. Continue to raise the temperature to 80°C and keep it for 5 h to obtain a phosphate intermediate.

[0065] (2) Alcoholysis reaction: Add 1.5 wt% n-propanol to the above phosphate intermediate and continue the reaction at 100 °C for 1 h. After cooling, phosphate is obtained.

[0066] Upon testing, the molar content of free phosphoric acid in the phosphate ester was 0.0%.

[0067] Example 2

[0068] A phosphate ester is prepared by the following method.

[0069] (1) Esterification reaction: Phosphorus pentoxide was added to polypropylene glycol (Mn: 1500) with a water content of 1100 ppm at 60 °C. The ratio of the molar number of hydroxyl groups in the raw material to the molar number of phosphorus pentoxide was 2.3:1. The temperature was then raised to 90 °C and kept for 8 h to obtain a phosphate intermediate.

[0070] (2) Alcoholysis reaction: 1.5 wt% n-butanol was added to the above phosphate intermediate, and the reaction was continued at 95 °C for 2 h. After cooling, the phosphate was obtained.

[0071] Upon testing, the molar content of free phosphoric acid in the phosphate ester was 0.0%.

[0072] Example 3

[0073] A phosphate ester is prepared by the following method.

[0074] (1) Esterification reaction: Phosphorus pentoxide was added to butanol-terminated polyoxyethylene-polyoxypropylene random mixed polyether (Mn: 1000) with a water content of 800 ppm at 20°C. The ratio of the molar number of hydroxyl groups in the raw material to the molar number of phosphorus pentoxide was 2.7:1. The temperature was then raised to 65°C and kept for 4 h to obtain a phosphate intermediate.

[0075] (2) Alcoholysis reaction: add 1.5 wt% isopropanol to the above phosphate intermediate and control the temperature at 115 °C to continue the reaction for 1 h. After cooling, the phosphate is obtained.

[0076] Upon testing, the molar content of free phosphoric acid in the phosphate ester was 0.0%.

[0077] Example 4

[0078] A phosphate ester is prepared by the following method.

[0079] (1) Esterification reaction: Glycerol ether (Mn: 3000) with a water content of 1600 ppm was added with phosphorus pentoxide at 50 °C. The ratio of the molar number of hydroxyl groups in the raw material to the molar number of phosphorus pentoxide was 2.2:1. The temperature was then raised to 85 °C and kept for 10 h to obtain a phosphate ester intermediate.

[0080] (2) Alcoholysis reaction: 1.5 wt% isobutanol was added to the above phosphate intermediate, and the reaction was continued at 105 °C for 4 h. After cooling, the phosphate was obtained.

[0081] Upon testing, the molar content of free phosphoric acid in the phosphate ester was 0.0%.

[0082] Example 5

[0083] A phosphate ester is prepared by the following method.

[0084] (1) Esterification reaction: Phosphorus pentoxide is added to polytetrahydrofuran (Mn: 1000) with a water content of 600 ppm at 80°C. The ratio of the molar number of hydroxyl groups in the raw material to the molar number of phosphorus pentoxide is 2.7:1. The temperature is then raised to 85°C and kept for 6 h to obtain a phosphate intermediate.

[0085] (2) Alcoholysis reaction: 1.5 wt% methanol was added to the above phosphate intermediate, and the reaction was continued at 85 °C for 2 h. After cooling, the phosphate was obtained.

[0086] Upon testing, the molar content of free phosphoric acid in the phosphate ester was 0.0%.

[0087] Example 6

[0088] A phosphate ester is prepared by the following method.

[0089] (1) Esterification reaction: Phosphorus pentoxide was added to butanol-terminated polyoxyethylene-polyoxypropylene random mixed polyether (Mn: 2000) with a water content of 400 ppm at 40°C. The ratio of the molar number of hydroxyl groups in the raw material to the molar number of phosphorus pentoxide was 2.5:1. The temperature was then raised to 95°C and kept for 6 h to obtain a phosphate intermediate.

[0090] (2) Alcoholysis reaction: Add 1.5 wt% ethanol to the above phosphate intermediate and continue the reaction at 95 °C for 0.5 h. After cooling, phosphate is obtained.

[0091] Upon testing, the molar content of free phosphoric acid in the phosphate ester was 0.0%.

[0092] Example 7

[0093] A phosphate ester is synthesized by the following method: adding phosphorus pentoxide to polypropylene glycol (Mn: 1500) with a water content of 3000 ppm at a temperature of 70°C, wherein the ratio of the molar number of hydroxyl groups in the raw material to the molar number of phosphorus pentoxide is 1.8:1, and the temperature is continuously raised to 90°C and kept for 10 hours to obtain a phosphate ester intermediate.

[0094] 1.5 wt% n-butanol was added to the above phosphate intermediate and the reaction was continued at 110 °C for 2 h. After cooling, phosphate was obtained.

[0095] The free phosphoric acid content in the phosphate ester was found to be 6.1% by molar amount.

[0096] Example 8

[0097] A phosphate ester is synthesized by the following method: adding phosphorus pentoxide to butanol-terminated polyoxyethylene-polyoxypropylene random mixed polyether (Mn: 1800) with a water content of 2300 ppm at a temperature of 50°C, wherein the ratio of the molar number of hydroxyl groups in the raw material to the molar number of phosphorus pentoxide is 2.7:1, and the temperature is continuously raised to 80°C and kept for 6 hours to obtain a phosphate ester intermediate.

[0098] 1.5 wt% n-butanol was added to the above phosphate intermediate and the reaction was continued at 105 °C for 2 h. After cooling, phosphate was obtained.

[0099] The free phosphoric acid content in the phosphate ester was found to be 9.6% by molar amount.

[0100] Example 9

[0101] A phosphate ester is synthesized by the following method: adding phosphorus pentoxide to butanol-terminated polyoxyethylene-polyoxypropylene random mixed polyether (Mn: 1000) with a water content of 800 ppm at a temperature of 50°C, wherein the ratio of the molar number of hydroxyl groups in the raw material to the molar number of phosphorus pentoxide is 3.5:1, and the temperature is continuously raised to 90°C and kept for 6 hours to obtain a phosphate ester intermediate.

[0102] 1.5 wt% n-propanol was added to the above phosphate intermediate and the temperature was controlled at 105 °C to continue the reaction for 2 h. After cooling, the phosphate was obtained.

[0103] The free phosphoric acid content in the phosphate ester was found to be 2.3% by molar ratio.

[0104] Comparative Example 1

[0105] A phosphate ester is synthesized by the following method: adding phosphorus pentoxide to polyethylene glycol (Mn: 600) with a water content of 1200 ppm at a temperature of 50°C, wherein the ratio of the molar number of hydroxyl groups in the raw material to the molar number of phosphorus pentoxide is 2.5:1, and the temperature is continuously raised to 80°C and kept for 6 hours to obtain a phosphate ester intermediate.

[0106] 1.5 wt% deionized water was added to the phosphate intermediate and the reaction was continued at 105 °C for 2 h. After cooling, the phosphate was obtained.

[0107] The free phosphoric acid content in the phosphate ester was found to be 5.3% by molar amount.

[0108] Comparative Example 2

[0109] A phosphate ester is synthesized by the following method: adding phosphorus pentoxide to butanol-terminated polyoxyethylene-polyoxypropylene random mixed polyether (Mn: 1000) with a water content of 1200 ppm at 60°C, wherein the ratio of the molar number of hydroxyl groups in the raw material to the molar number of phosphorus pentoxide is 2.6:1, and the temperature is continuously raised to 85°C and kept for 6 hours to obtain a phosphate ester intermediate.

[0110] 1.5 wt % deionized water was added to the above phosphate intermediate and the temperature was controlled at 105 ° C to continue the reaction for 2 h. After cooling, the phosphate was obtained.

[0111] The free phosphoric acid content in the phosphate ester was found to be 1.9% by molar amount.

Claims

1. A method for preparing a phosphate ester, characterized in that: The following steps are involved: (1) Esterification reaction: Esterification reaction of organic alcohol compounds with phosphorus pentoxide to obtain phosphate intermediates; (2) Alcoholysis reaction: Add C 1- C8 monohydric alcohol is used to alcoholize the polyphosphate in the phosphate intermediate to obtain the phosphate.

2. The method for preparing a phosphoric acid ester according to claim 1, characterized in that: Meet one or more of the following conditions: (1) The organic alcohol compound is selected from at least one of fatty alcohol and terminal hydroxyl polymer; preferably a terminal hydroxyl polymer; Furthermore, the terminal hydroxyl polymer is selected from at least one of alkoxy polyethylene glycol, alkoxy polypropylene glycol, random or block polyether of alkoxy polyethylene glycol polypropylene glycol, polyether diol, polyether polyol, and polytetrahydrofuran; the alkoxy group in the terminal hydroxyl polymer is a normal alkyl group having 1 to 18 carbon atoms or its isomers; Furthermore, the terminal hydroxyl polymer is selected from at least one of polyethylene glycol, polypropylene glycol, butanol-terminated polyoxyethylene-polyoxypropylene random mixed polyether, glycerol ether, and polytetrahydrofuran; (2) C 1- The C8 monohydric alcohol is selected from at least one of methanol, ethanol, n-propanol, isopropanol, butanol, isobutanol, tert-butanol, n-pentanol and its isomeric alcohols, n-hexanol and its isomeric alcohols, n-heptanol and its isomeric alcohols, and n-octanol and its isomeric alcohols; Preferably, the C 1- The C8 monohydric alcohol is selected from at least one of n-propanol, n-butanol, isopropanol, isobutanol, methanol and ethanol.

3. The method for preparing a phosphoric acid ester according to claim 1, characterized in that: The organic alcohol compound is a hydroxyl-terminated polymer, and the weight average molecular weight of the hydroxyl-terminated polymer is 200-5000, preferably 1000-3000, for example, 1000, 1500, 2000, 3000.

4. The method for preparing a phosphoric acid ester according to any one of claims 1 to 3, characterized in that: Meet one or more of the following conditions: (1) The water content of the organic alcohol compound is less than 2000 ppm; further, the water content of the organic alcohol compound is less than 1600 ppm, less than 1100 ppm, less than 800 ppm, less than 600 ppm, less than 400 ppm; (2) In the esterification reaction, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.0-3.0:1, preferably 2.2-2.7:1, for example: 2.2:1, 2.3:1, 2.5:1, 2.6:1, 2.7:1; (3) In the alcoholysis reaction, the C 1- The amount of C8 monohydric alcohol added is 0.5-5 wt % of the phosphate intermediate, preferably 1-2 wt %, for example, 1.5 wt %.

5. The method for preparing a phosphoric acid ester according to any one of claims 1 to 3, characterized in that: Meet one or more of the following conditions: (1) In the esterification reaction, the phosphorus pentoxide is added when the temperature of the organic alcohol compound is controlled to be 10-80°C; preferably, the phosphorus pentoxide is added when the temperature of the organic alcohol compound is 20°C-80°C, for example, 20°C, 40°C, 50°C, 60°C, or 80°C; (2) In the esterification reaction, the temperature of the esterification reaction is 50-110°C; preferably, the temperature of the esterification reaction is 65-95°C, for example: 65°C, 80°C, 85°C, 90°C, 95°C; (3) In the esterification reaction, the esterification reaction time is 1-10 hours; preferably, the esterification reaction time is 4-10 hours, for example: 4 hours, 5 hours, 6 hours, 8 hours, 10 hours; (4) In the alcoholysis reaction, the temperature of the alcoholysis reaction is 85-115°C; preferably, the temperature of the alcoholysis reaction is 85-115°C, for example, 85°C, 95°C, 100°C, 105°C, 115°C; (5) In the alcoholysis reaction, the alcoholysis reaction time is 0.5-10 h; preferably, the esterification reaction time is 0.5-4 h, for example: 0.5 h, 1 h, 2 h, 4 h.

6. The method for preparing a phosphoric acid ester according to claim 1, characterized in that: Choose one of the following options: Option 1: The organic alcohol compound is polyethylene glycol with a number average molecular weight of 800-1200, and the C 1- The C8 monohydric alcohol is propanol, the water content of the organic alcohol compound is ≤1000 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.2-3.0:1, in the esterification reaction, the feeding temperature is 10-30°C, the reaction temperature is 70-90°C, and the reaction time is 4-6 h, and in the alcoholysis reaction, the reaction temperature is 90-110°C, and the reaction time is 0.5-1.5 h; Preferably, the organic alcohol compound is polyethylene glycol with a number average molecular weight of 1000, and the C 1- The C8 monohydric alcohol is n-propanol, the water content of the organic alcohol compound is ≤800 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.6:1, in the esterification reaction, the feeding temperature is 20°C, the reaction temperature is 80°C, and the reaction time is 5 h, and in the alcoholysis reaction, the reaction temperature is 100°C and the reaction time is 1 h; Option 2: The organic alcohol compound is polypropylene glycol with a number average molecular weight of 1200-1800, and the C 1- The C8 monohydric alcohol is butanol, the water content of the organic alcohol compound is ≤1300 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.1-2.5:1, in the esterification reaction, the feeding temperature is 50-70°C, the reaction temperature is 80-100°C, and the reaction time is 7-9 h, and in the alcoholysis reaction, the reaction temperature is 85-105°C, and the reaction time is 1-3 h; Preferably, the organic alcohol compound is polypropylene glycol with a number average molecular weight of 1500, 1- The C8 monohydric alcohol is n-butanol, the water content of the organic alcohol compound is ≤1100 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.3:1, in the esterification reaction, the feeding temperature is 60°C, the reaction temperature is 90°C, and the reaction time is 8 h, and in the alcoholysis reaction, the reaction temperature is 95°C and the reaction time is 2 h; Option 3: The organic alcohol compound is a butanol-terminated polyoxyethylene-polyoxypropylene random mixed polyether with a number average molecular weight of 800-1200, and the C 1- The C8 monohydric alcohol is propanol, the water content of the organic alcohol compound is ≤1000 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.5-2.9:1, the feeding temperature in the esterification reaction is 10-30°C, the reaction temperature in the esterification reaction is 55-75°C, and the reaction time is 3-5 h, and the reaction temperature in the alcoholysis reaction is 105-115°C, and the reaction time is 0.5-1.5 h; Preferably, the organic alcohol compound is a butanol-terminated polyoxyethylene-polyoxypropylene random mixed polyether with a number average molecular weight of 1000, and the C 1- The C8 monohydric alcohol is isopropanol, the water content of the organic alcohol compound is ≤800 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.7:1, the feeding temperature in the esterification reaction is 20°C, the reaction temperature in the esterification reaction is 65°C and the reaction time is 4 h, and the reaction temperature in the alcoholysis reaction is 115°C and the reaction time is 1 h; Option 4: The organic alcohol compound is a glycerol ether with a number average molecular weight of 2500-3500, 1- The C8 monohydric alcohol is butanol, the water content of the organic alcohol compound is ≤1800 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.0-2.4:1, in the esterification reaction, the feeding temperature is 40-60°C, the reaction temperature is 75-95°C, and the reaction time is 9-10 h, and in the alcoholysis reaction, the reaction temperature is 95-115°C, and the reaction time is 3-5 h; Preferably, the organic alcohol compound is a glycerol ether with a number average molecular weight of 3000, 1- The C8 monohydric alcohol is isobutyl alcohol, the water content of the organic alcohol compound is ≤1600 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.2:1, in the esterification reaction, the feeding temperature is 50°C, the reaction temperature is 85°C, and the reaction time is 10 h, and in the alcoholysis reaction, the reaction temperature is 105°C and the reaction time is 4 h; Option 5: The organic alcohol compound is polytetrahydrofuran with a number average molecular weight of 800-1200, and the C 1- The C8 monohydric alcohol is methanol, the water content of the organic alcohol compound is ≤800 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.5-2.9:1, the feeding temperature in the esterification reaction is 70-90°C, the reaction temperature in the esterification reaction is 75-95°C, and the reaction time is 4-5-7 h, and the reaction temperature in the alcoholysis reaction is 75-95°C, and the reaction time is 1-3 h; Preferably, the organic alcohol compound is polytetrahydrofuran with a number average molecular weight of 1000, and the C 1- The C8 monohydric alcohol is methanol, the water content of the organic alcohol compound is ≤600 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.7:1, the feeding temperature in the esterification reaction is 80°C, the reaction temperature in the esterification reaction is 85°C and the reaction time is 6 h, and the reaction temperature in the alcoholysis reaction is 85°C and the reaction time is 2 h; Option 6: The organic alcohol compound is a butanol-terminated polyoxyethylene-polyoxypropylene random mixed polyether with a number average molecular weight of 1800-2200. 1- The C8 monohydric alcohol is ethanol, the water content of the organic alcohol compound is ≤600 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.3-2.7:1, the feeding temperature in the esterification reaction is 30-50°C, the reaction temperature in the esterification reaction is 85-105°C, and the reaction time is 5-7 h, and the reaction temperature in the alcoholysis reaction is 85-105°C, and the reaction time is 0.5-1 h; Preferably, the organic alcohol compound is a butanol-terminated polyoxyethylene-polyoxypropylene random mixed polyether with a number average molecular weight of 2000, and the C 1- The C8 monohydric alcohol is ethanol, the water content of the organic alcohol compound is ≤400 ppm, the molar ratio of the hydroxyl group in the organic alcohol compound to the phosphorus pentoxide is 2.5:1, the feeding temperature in the esterification reaction is 40°C, the reaction temperature in the esterification reaction is 95°C and the reaction time is 6 h, and the reaction temperature in the alcoholysis reaction is 95°C and the reaction time is 0.5 h.

7. The method for preparing a phosphoric acid ester according to claim 1, characterized in that: The molar content of free phosphoric acid in the phosphate ester is less than 1.0%; preferably, the molar content of free phosphoric acid in the phosphate ester is less than 0.5%, for example, less than 0.2%, less than 0.1%, less than 0.05%, less than 0.01%.

8. The phosphate ester prepared by the method for preparing the phosphate ester according to any one of claims 1 to 7.

9. Use of the phosphate ester according to claim 8 as an additive in a positive electrode slurry of a lithium battery.

10. The use according to claim 9, characterized in that The positive electrode slurry is selected from at least one of lithium iron phosphate slurry and lithium iron manganese phosphate slurry.