Synthesis method of polymethylphosphonic acid glycol ester

Abstract

The invention discloses a synthesis method of polymethylphosphonic acid glycol ester, which belongs to the technical field of polymethylphosphonic acid glycol ester preparation, and comprises the following steps: adding a solvent and ethylene glycol into a reaction bottle, stirring and cooling to 0-5 DEG C; placing molten methyl phosphorus oxychloride in a constant-pressure dropping funnel, and adding a solvent for dissolving and diluting to obtain a mixed solution; dropwise adding the mixed solution into a reaction bottle, wherein the temperature is controlled to be not higher than 5 DEG C in the dropwise adding process; carrying out deacidification treatment to obtain an intermediate product; and stirring and heating the intermediate product to 75 DEG C, and continuously introducing ethylene oxide for 2-6 hours to obtain the product. According to the method, methyl phosphorus oxychloride reacts with ethylene glycol, halogen is replaced, the product is obtained through ethylene oxide end capping, the byproduct serving as a low-boiling-point substance can be removed, and no catalyst is used, so that the acid value of the product PEMP is low.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of poly(ethylene glycol methyl phosphonate), and in particular relates to a method for synthesizing poly(ethylene glycol methyl phosphonate). Background Art

[0002] Polyethylene methylphosphonate (PEMP) is a new type of reactive flame retardant that does not contain halogens compared to traditional additive halogenated phosphates. PEMP's Clariant flame retardant trade name is Exolit® OP 560, a yellow slightly turbid liquid, a medium viscosity reactive non-halogenated phosphorus-containing polyol with a functionality of about 2. A flame retardant that can be used in flexible polyurethane foams.

[0003] PEMP has the characteristics of high flame retardant efficiency, no release of corrosive hydrogen halide gas during combustion, no precipitation, little effect on the physical and mechanical properties of the material, stable and durable flame retardancy, etc. When the dosage is 6 parts (relative to the amount of polyether), the fogging value of the polyurethane foam flame-retarded by it is less than 1mg, while under the same conditions, the fogging value of the polyurethane foam flame-retarded by TDCPP is as high as 14mg. To achieve the same flame retardant level, the dosage of PEMP is only about one-third (1 / 3) of TCPP, which is cost-effective. Halogen-free flame retardant PEMP contains up to 12% phosphorus. Adding 4.5~8 parts of PEMP to 100 parts of polyether polyol can pass the US MVSS302 standard, and has low fogging value, low volatility / non-volatility, and low VOC.

[0004] The master's thesis "Preparation of Flame Retardant Polyethylene Methylphosphonate" uses the ester exchange method to synthesize PEMP. The raw materials are diethyl methylphosphonate (or dimethyl methylphosphonate) and ethylene glycol, and then the product is capped with ethylene oxide. The yield of this scheme is as low as 60~70%, and it contains a large amount of impurity dimethyl methylphosphonate (DMMP) due to incomplete esterification. In addition, the catalyst used in the reaction remains in the product and is difficult to remove, which affects the foaming performance of the flame retardant and causes the product PEMP to have a high acid value. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method for synthesizing poly(ethylene glycol methyl phosphonate), wherein methyl dichlorophosphine reacts with ethylene glycol to replace halogen, and then the product is capped with ethylene oxide, and the by-product can be removed as a low-boiling substance. The present invention does not use a catalyst, so that the product PEMP has a low acid value.

[0006] The objective of the present invention is achieved through the following technical solutions: A method for synthesizing poly(ethylene glycol methyl phosphonate) comprises the following steps: Step 1: Add the solvent and ethylene glycol into the reaction bottle, stir and cool to 0-5°C; Step 2: placing the melted methyl phosphorus oxychloride in a constant pressure dropping funnel, and adding a solvent to dissolve and dilute to obtain a mixed solution; Step 3: Add the mixed solution dropwise into the reaction bottle, and control the temperature during the addition process to be no higher than 5°C; Step 4: performing deacidification treatment to obtain an intermediate product; Step 5: Stir the intermediate product and heat it to 75°C, and continue to introduce ethylene oxide for 2-6 hours to obtain the product.

[0007] Preferably, in step 1, the mass ratio of the solvent to ethylene glycol is 1:1.5-3.5.

[0008] Preferably, in step 2, the mass ratio of methyl phosphorus oxychloride to solvent is 1:0.5-2.

[0009] Preferably, the solvent is dichloromethane, dichloroethane or toluene.

[0010] Preferably, the molar ratio of methyl phosphorus oxychloride to ethylene glycol is 0.5-2:1-5.

[0011] Preferably, in the step 4, after the dropwise addition is completed, the solvent and hydrogen chloride are evaporated under reduced pressure (5-6 KPa); after the internal temperature of the reaction is warmed up to 15-25°C, the material is continuously pumped into the packing column film for deacidification under the same vacuum degree, the packing column is insulated by a water bath, and deacidification is performed at 30°C, 60°C, and 80°C, respectively, and the bottom liquid is collected and slowly heated to 130°C under a vacuum of 200-500 Pa to continue deacidification for 0.5-3h.

[0012] Preferably, in the step 4, the material is slowly dripped at a rate of 3-5 g / min; and the temperature is slowly raised to 130°C by intermittent heating, 10°C each time.

[0013] Preferably, in step five, replacement is required before heating, and the replacement specifically includes the following steps: replacing the intermediate product with nitrogen twice.

[0014] Preferably, in step five, the stirring speed is 150-300 r / min.

[0015] Preferably, the method further comprises step 6, wherein the product is subjected to a low-boiling treatment, and the temperature is slowly raised to 130° C. under reduced pressure (200-500 Pa) by an oil pump, and the temperature is raised intermittently, 10° C. each time, and the low-boiling treatment is performed for 0.5-3 hours to obtain the product.

[0016] The beneficial effects of this technical solution are as follows: 1. The present invention provides a method for synthesizing poly(ethylene glycol methyl phosphonate), wherein by-products (including hydrogen chloride and ethylene glycol produced by introducing ethylene oxide) can be removed as low-boiling substances, and no catalyst is used, so that the acid value of the product is low.

[0017] 2. The present invention provides a method for synthesizing poly(ethylene methyl phosphonate). Clariant synthesizes OP560 using an ester exchange method, in which the raw materials are diethyl methylphosphonate (or dimethyl methylphosphonate) reacting with ethylene glycol, and then end-capping with ethylene oxide to obtain the product; while the present invention uses a substitution method, in which the raw material is methyl dichlorophosphine (MPO) reacting with ethylene glycol to replace the halogen, and then end-capping with ethylene oxide to obtain the product. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0019] The hydrogen ion detection method, phosphorus content detection method, viscosity detection method, chloride ion detection method and hydroxyl value detection method in Examples 1 to 4 and Comparative Examples 1 to 5 are all prior art. The hydrogen ion detection method, phosphorus content detection method, viscosity detection method, chloride ion detection method and hydroxyl value detection method are described by citing one of the prior art.

[0020] Hydrogen ion detection method: Weigh an appropriate amount of sample into a conical flask, add an appropriate amount of distilled water, add 2 drops of methyl red indicator, and titrate with 0.1 mol / L sodium hydroxide standard solution. The solution just turns yellow and the yellow color does not disappear within 30 seconds. Then calculate the hydrogen ion concentration.

[0021] Phosphorus content detection method: Instrument brand model: Lianhua Technology Multi-parameter Water Quality Analyzer 5B-6C. Accurately weigh the sample and dissolve it in water, add potassium persulfate, and digest it under heating and pressure conditions to convert all phosphorus into phosphate. Add ammonium molybdate color developer, and the phosphate reacts with it with a characteristic color reaction. Measure the absorbance at a specified wavelength, and calculate the phosphorus content based on the reading.

[0022] Viscosity test method: Instrument brand model: Bangsi Technology Instrument Shanghai Co., Ltd., NDJ-8S digital display viscometer. Adjust the instrument level, select a suitable rotor, immerse the rotor completely in the sample, set the instrument parameters, adjust the speed, make the percentage reading close to 50%, and then read the viscosity value.

[0023] The potentiometric titration used in the chloride ion detection method is as follows: accurately weigh an appropriate amount of sample, and if the chloride ion content is low, weigh about 2g, then ultrasonically dissolve it with an appropriate amount of deionized water, and adjust the pH to weak acidity with dilute nitric acid. Use an automatic potentiometric titrator equipped with a silver electrode for titration, set the jump to 80mV / mL, drop in a standard silver nitrate solution, and when the potentiometric titrator prompts the end point, calculate the chloride ion content based on the volume and concentration of the silver nitrate dropped.

[0024] Hydroxyl value detection method: In a DMF solution at 45°C, acetic anhydride is catalyzed by N-methylimidazole to cause a quantitative acylation reaction between the hydroxyl groups in the polyester polyol. The mechanism is related to the formation of an N-acetyl-N-methylimidazole ion intermediate. After adding water to hydrolyze the excess acetic anhydride, thymolphthalein solution is used as an indicator, and NaOH standard solution is used to neutralize the by-product acetic acid produced in the acylation process and the acetic acid generated by hydrolysis. The hydroxyl value is calculated based on the volume difference of the NaOH solution consumed by the titration blank and the sample solution.

[0025] Example 1 Add 128g (2.0mol) of ethylene glycol to a 1000ml three-necked flask, then add 65g of ethylene dichloride to dilute, and stir to cool to 0℃ in an ice-salt bath; take another 136.34g (1mol) of melted methyl dichlorophosphorus oxychloride in a 250ml constant pressure dropping funnel, add 134g of ethylene dichloride to dissolve and dilute, and slowly drop it into the reaction bottle. The temperature during the dropping process is controlled not to be higher than 5℃. After the dropping is completed, reduce the pressure (5~6Kpa) and evaporate The solvent and hydrogen chloride were removed; after the internal temperature of the reaction returned to 20°C, the material was continuously pumped into the packing column for thin film deacidification under the same vacuum degree, with a feeding rate of 3-5 g / min. The packing column was kept warm in a water bath and deacidified at 30°C, 60°C and 80°C for 3 times, respectively. After the bottom liquid was collected, it was slowly heated to 130°C under a vacuum of 200-500 Pa and continued to deacidify for 1 hour; finally, 80 g of thick transparent liquid A (i.e., intermediate product A) was obtained, and sampling and detection were performed: Cl - :0.016%, H + :0.13%.

[0026] The thick transparent liquid A (i.e., intermediate product A) was replaced with nitrogen twice, heated to 75°C with stirring (speed 150r / min), and ethylene oxide was continuously introduced for 4h to obtain product A. Product A was further heated to 130°C under a vacuum of 200-500Pa to remove the low boiling point for 1h to obtain product A. Product A was sampled and tested for H + : 0.0032%, after removing the low boiling point: H + : 0.00049%, equivalent to 0.27 mg KOH / g (direct conversion 0.00049*560=0.27); P: 14.33%, viscosity: 292 mPa·s; chloride ion: 0.015%; hydroxyl value: 255 mg•KOH / g.

[0027] Example 2 Add 3.5 mol of ethylene glycol to a 2000 ml three-necked flask, then add 1 mol of dichloromethane to dilute, stir and cool to 5 ° C in an ice-salt bath, take another 1.75 mol of melted methyl dichlorophosphorus oxychloride in a constant pressure dropping funnel, add 3.5 mol of dichloromethane to dissolve and dilute, slowly add it dropwise to the reaction bottle, and control the temperature not higher than 5 ° C during the dropping process. After the dropping is completed, reduce the pressure (5~6Kpa) to evaporate the solvent and hydrogen chloride; when the temperature returns to 25 ° C, continue to pump the material into the packing column film deacidification under the same vacuum degree, the feeding rate is 3~5g / min, the packing column is insulated by a water bath, and deacidification is performed 3 times at 30 ° C, 60 ° C, and 80 ° C respectively. After the bottom liquid is collected, it is slowly heated to 130 ° C under a vacuum of 200~500Pa and continues to deacidify for 3h; finally, 140g of thick transparent liquid B (i.e., intermediate product B) is obtained, and sampling and detection: Cl - :0.016%, H + :0.21%.

[0028] The thick transparent liquid B (i.e., intermediate product B) was replaced with nitrogen twice, heated to 75°C with stirring (speed 150r / min), and ethylene oxide was continuously introduced for 6h to obtain product B. Product B was slowly heated to 130°C under reduced pressure of an oil pump (200-500Pa) and de-boiled for 3h to obtain product B. Product B was sampled and tested for H + : 0.0045%, after removing the low boiling point: H + : 0.00082%, equivalent to 0.46 mg KOH / g (direct conversion 0.00082*560=0.46); P: 11.88%, viscosity: 381 mPa·s; chloride ion: 0.016%; hydroxyl value: 202 mg•KOH / g.

[0029] Example 3 Add 1.5 mol of ethylene glycol to a 1000 ml three-necked flask, then add 1 mol of toluene to dilute, stir and cool to 3 ° C in an ice-salt bath, take another 0.3 mol of melted methyl dichlorophosphorus in a constant pressure dropping funnel, add 0.6 mol of toluene to dissolve and dilute, slowly drop it into the reaction bottle, and control the temperature not higher than 5 ° C during the dropping process. After the dropping is completed, reduce the pressure (5~6Kpa) to evaporate the solvent and hydrogen chloride; when the temperature returns to 15 ° C, continue to pump the material into the packing column film deacidification under the same vacuum degree, the feeding rate is 3~5g / min, the packing column is insulated by a water bath, and deacidification is performed 3 times at 30 ° C, 60 ° C, and 80 ° C respectively. After the bottom liquid is collected, it is slowly heated to 130 ° C under a vacuum of 200~500Pa and continued to deacidify for 0.5h; 24g of thick transparent liquid C (i.e., intermediate product C) is obtained, and sampling and detection: Cl - :0.015%,H + :0.35%.

[0030] The thick transparent liquid C (i.e., intermediate product C) was replaced with nitrogen twice, heated to 75°C with stirring (speed 220r / min), and ethylene oxide was continuously introduced for 2h to obtain product C. Product C was slowly heated to 130°C under reduced pressure of an oil pump (200-500Pa) and de-boiled for 0.5h to obtain product C. Product C was sampled and tested for H + : 0.0079%, after removing the low boiling point: H + : 0.00351%, equivalent to 1.97 mg KOH / g (direct conversion 0.00351*560=1.97); P: 9.54%, viscosity: 476 mPa·s; chloride ion: 0.016%; hydroxyl value: 169 mg•KOH / g.

[0031] Example 4 The difference between this embodiment and embodiment 3 is that 2.5 mol of ethylene glycol is added to a 1000 ml three-necked flask, and then 1 mol of toluene is added for dilution, and the mixture is stirred and cooled to 3° C. in an ice-salt bath, and 1 mol of melted methyl dichlorophosphorus is taken into a constant pressure dropping funnel, and 1.5 mol of toluene is added for dissolution and dilution to obtain a thick transparent liquid D (i.e., intermediate product D) and a product D. Thick transparent liquid D (i.e., intermediate product D) is sampled for detection: Cl - :0.029%, H + :0.23 %. Product D sampling test H + :0.0063 %, after removing low boiling point: H + : 0.00211 %, equivalent to 1.18 mgKOH / g (direct conversion 0.00211 *560= 1.18); P: 15.36%, viscosity: 151mPa·s; chloride ion: 0.028 %; hydroxyl value: 182 mg•KOH / g.

[0032] Comparative Example 1 The difference between this comparative example and Example 1 is that 128 g (2.0 mol) of ethylene glycol was added to a 1000 ml three-necked flask, and then 65 g of ethylene dichloride was added for dilution, and stirred and cooled to 6°C in an ice-salt bath to obtain a thick transparent liquid E (i.e., intermediate product E) and product E. Thick transparent liquid E (i.e., intermediate product E) was sampled and tested: Cl - :0.015%,H + :0.15 %. Product E sampling test H + :0.0058 %, after removing low boiling point: H + : 0.00082%, equivalent to 0.46 mgKOH / g (direct conversion 0.00082 *560=0.46); P: 16.51%, viscosity: 398 mPa·s; chloride ion: 0.0057%; hydroxyl value: 203 mg•KOH / g.

[0033] Comparative Example 2 The difference between this comparative example and Example 1 is that: 3.5 mol of ethylene glycol is added to a 2000 ml three-necked flask, and then 1 mol of dichloromethane is added to dilute it, and it is stirred and cooled to 5°C in an ice-salt bath; 1.75 mol of melted methyl dichlorophosphorus oxychloride is taken in a constant pressure dropping funnel, 3.5 mol of dichloromethane is added to dissolve and dilute it, and it is slowly dripped into the reaction bottle, and the temperature during the dripping process is controlled not to be higher than 10°C, to obtain a thick transparent liquid F (i.e., intermediate product F) and a product F. Thick transparent liquid F (i.e., intermediate product F), sampling and detection: Cl - :0.016%, H + :0.33 %. Product E sampling test H + :0.0097 %, after removing low boiling point: H + : 0.00388%, equivalent to 2.17 mgKOH / g (direct conversion 0.00388 *560= 2.17); P: 16.64%, viscosity: 506 mPa·s; chloride ion: 0.0068%; hydroxyl value: 169 mg•KOH / g.

[0034] Comparative Example 3 The difference between this comparative example and Example 2 is that no low boiling point removal treatment is performed; a thick transparent liquid G (i.e., intermediate product G) and a product G are obtained. The thick transparent liquid G (i.e., intermediate product G) is sampled and tested: Cl - :0.016%, H + :0.53%. Product G sampling test H + : 0.0051%, after removing the low boiling point: H + : 0.00097%, equivalent to 0.54 mgKOH / g (direct conversion 0.00097 *560=0.54); P: 10.95%, viscosity: 423 mPa·s; chloride ion: 0.016%; hydroxyl value: 236 mg•KOH / g.

[0035] Comparative Example 4 The difference between this comparative example and Example 2 is that: deacidification is performed once at 60°C to obtain a thick transparent liquid H (i.e., intermediate product H) and a product H. Thick transparent liquid H (i.e., intermediate product H) was sampled and tested: Cl - :0.015%,H + :0.72%. Product H sampling test H + : 0.025%, after removing the low boiling point: H +: 0.0056%, equivalent to 3.14 mgKOH / g (direct conversion 0.0056 *560=3.14); P: 9.83%, viscosity: 591 mPa·s; chloride ion: 0.0077%; hydroxyl value: 133 mg•KOH / g.

[0036] Comparative Example 5 The difference between this comparative example and Example 3 is that the intermediate product is not replaced before heating, and a thick transparent liquid I (i.e., intermediate product I) and product I are obtained. Thick transparent liquid I (i.e., intermediate product I), sampling and detection: Cl - :0.016%, H + :0.33%. Product I sampling test H + : 0.0077%, after removing the low boiling point: H + : 0.00355%, equivalent to 1.99 mg KOH / g (direct conversion 0.00355*560=1.99); P: 9.58%, viscosity: 475 mPa·s; chloride ion: 0.016%; hydroxyl value: 168 mg•KOH / g.

[0037] Comparative Example 1 Compared with Example 1, H + and chloride ions increased significantly; Comparative Example 2 compared with Example 1, P, H + , chloride ions and viscosity increased significantly, and the hydroxyl value decreased; Comparative Example 3 compared with Example 2, P, H + , chloride ions and viscosity increased significantly, and the hydroxyl value decreased; Comparative Example 4 compared with Example 2, P, H + , chloride ions and viscosity are significantly increased, and the hydroxyl value is reduced; compared with Example 3, the parameters of the product in Comparative Example 5 are basically the same, but there are safety risks.

[0038] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for synthesizing poly(ethylene glycol methyl phosphonate), characterized in that: The following steps are involved: Step 1: Add the solvent and ethylene glycol into the reaction bottle, stir and cool to 0-5°C; Step 2: placing the melted methyl phosphorus oxychloride in a constant pressure dropping funnel, and adding a solvent to dissolve and dilute to obtain a mixed solution; Step 3: Add the mixed solution dropwise into the reaction bottle, and control the temperature during the addition process to be no higher than 5°C; Step 4: performing deacidification treatment to obtain an intermediate product; Step 5: Stir the intermediate product and heat it to 75°C, and continue to introduce ethylene oxide for 2-6 hours to obtain the product.

2. The method for synthesizing poly(ethylene glycol methyl phosphonate) according to claim 1, characterized in that: In the step 1, the mass ratio of the solvent to ethylene glycol is 1:1.5-3.

5.

3. The method for synthesizing poly(ethylene glycol methyl phosphonate) according to claim 1, characterized in that: In the step 2, the mass ratio of the methyl phosphorus oxychloride to the solvent is 1:0.5-2.

4. The method for synthesizing poly(ethylene glycol methyl phosphonate) according to claim 1, characterized in that: The solvent is dichloromethane, dichloroethane, toluene.

5. The method for synthesizing poly(ethylene glycol methyl phosphonate) according to claim 1, characterized in that: The molar ratio of the methyl phosphorus oxychloride to ethylene glycol is 0.5-2:1-5.

6. The method for synthesizing poly(ethylene glycol methyl phosphonate) according to claim 1, characterized in that: In the step 4, after the dropwise addition is completed, the solvent and hydrogen chloride are evaporated under reduced pressure (5-6Kpa); after the internal temperature of the reaction is warmed up to 15-25°C, the material is continuously pumped into the packing column film for deacidification under the same vacuum degree, and the packing column is insulated by a water bath and deacidified at 30°C, 60°C, and 80°C, respectively. After the bottom liquid is collected, the temperature is slowly raised to 130°C under a vacuum of 200-500Pa to continue deacidification for 0.5-3h.

7. The method for synthesizing poly(ethylene glycol methyl phosphonate) according to claim 6, characterized in that: In the step 4, the material is slowly dripped at a rate of 3-5 g / min; and the temperature is slowly raised to 130°C by intermittent heating, 10°C each time.

8. The method for synthesizing poly(ethylene glycol methyl phosphonate) according to claim 1, characterized in that: In the step 5, replacement is required before heating, and the replacement specifically includes the following steps: the intermediate product is replaced by nitrogen twice.

9. The method for synthesizing poly(ethylene glycol methyl phosphonate) according to claim 1, characterized in that: In the step 5, the stirring speed is 150-300 r / min.

10. The method for synthesizing poly(ethylene glycol methyl phosphonate) according to claim 1, characterized in that: The step also includes step six, wherein the product is subjected to a low-boiling treatment, the temperature is slowly raised to 130° C. under reduced pressure with an oil pump, and the temperature is raised intermittently, 10° C. each time, and the low-boiling treatment is performed for 0.5-3 hours; and the product is obtained.