Preparation method of chlorinated alkyl polyphosphate

Abstract

The invention relates to the field of chemical synthesis, in particular to a preparation method of chlorinated alkyl polyphosphate, which comprises the following steps: mixing diethylene glycol and gamma-valerolactone, slowly adding phosphorus oxychloride, and reacting at 20-50 DEG C to generate a reaction solution containing an intermediate; adding gamma-valerolactone and an IL (at) MOFs-P catalyst into the reaction solution, slowly adding epoxypropane, and reacting at 130-150 DEG C in a nitrogen atmosphere to generate a target product mixed solution; and recovering gamma-valerolactone through distillation, centrifugally separating the catalyst, regenerating and recycling, and purifying a crude product to obtain a final product. The green solvent gamma-valerolactone is adopted and recycled, the IL-coated MOFs-P catalyst is high in activity and can be recycled, side reactions are reduced by accurately controlling reaction conditions, the product yield reaches 90% or above, the purity exceeds 98%, and the method has the advantages of being green, environmentally friendly, economical and efficient.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of chemical synthesis, in particular to a preparation method of chloroalkyl polyphosphate. BACKGROUND

[0002] As an important class of phosphorus-containing flame retardants, chloroalkyl polyphosphate is widely used in the fields of plastics, rubber, coatings, etc. due to its good flame retardant efficiency, thermal stability and compatibility with high polymer materials. With the increasing environmental protection requirements, traditional halogen-containing flame retardants are gradually restricted due to the problem of releasing toxic gases during combustion, and phosphorus-containing flame retardants become the focus of substitution research. Among them, chloroalkyl polyphosphate enhances the flame retardant effect through the synergistic effect of phosphorus-chlorine in the molecular structure, and has the characteristics of low smoke and low toxicity, so the market demand continues to grow.

[0003] Currently, the preparation of chloroalkyl polyphosphate mostly adopts traditional solvent method, using benzene or halogenated hydrocarbon as reaction medium. Such solvents have the problems of strong volatility, high toxicity, serious environmental pollution, etc., and are difficult to recover, which does not meet the development concept of green chemistry.

[0004] During the reaction, the raw material phosphorus oxychloride is easily hydrolyzed by water, resulting in loss of raw materials and increase of by-products, which needs to be strictly controlled; at the same time, the ring-opening addition reaction of propylene oxide has high requirements for the activity and selectivity of the catalyst, and the traditional catalyst has the problems of uneven dispersion of active sites, easy deactivation and difficult recovery, etc., resulting in low yield and purity of the product; in addition, the problems of temperature fluctuation and insufficient mass transfer efficiency in the existing process easily cause crosslinking and chain scission side reactions, further reducing the quality of the product. SUMMARY

[0005] In order to solve the foregoing technical problems, the present application provides a preparation method of chloroalkyl polyphosphate, which solves the problems of large solvent pollution, many side reactions, low product yield and low purity in the traditional process by using a new type of solvent and catalyst, and the specific technical scheme is as follows.

[0006] The present application provides a preparation method of chloroalkyl polyphosphate, which specifically comprises the following steps: Step 1: add a mixed solution of diethylene glycol and gamma-valerolactone solvent into a glass reaction kettle with stirring and tail gas absorption device, add phosphorus oxychloride, the addition time is 5-10 min, heat to 20-50℃ for 2-3 hours, continuously stir during the reaction, and absorb and treat the generated hydrogen chloride gas to obtain a reaction liquid containing intermediates; Step 2: Add gamma-valerolactone and IL@MOFs-P catalyst to the reaction solution of step 1, add propylene oxide, the addition time is 10-12 min, heat the reactor to 130-150℃, continuously pass nitrogen, the stirring rate is 300-400 r / min, react for 4-6 hours, obtain a mixed solution containing chloroalkyl polyphosphates; Step 3: Transfer the mixed solution obtained in step 2 to a normal pressure distillation column for distillation separation, the distillation column temperature is 210-215℃, obtain gamma-valerolactone recovery solution and chloroalkyl polyphosphate mixed solution containing IL@MOFs-P catalyst; Step 4: After the recovered gamma-valerolactone is refined by activated carbon adsorption for 1-2 h, it is transported to step 1 and step 2 for recycling; Step 5: Centrifugal separation of the mixed solution in step 3 to obtain solid catalyst and chloroalkyl polyphosphate crude product; After the IL@MOFs-P catalyst is washed with gamma-valerolactone for 2-3 times, it is nitrogen purged at 120℃ for 2 hours; After the chloroalkyl polyphosphate crude product is washed with deionized water for 2 times, the water phase is removed, anhydrous sodium sulfate solid particles are added, after standing for 12 hours, the filtrate is obtained by filtration, and the final product is obtained after vacuum drying.

[0007] Preferably, in step 2, the preparation method of IL@MOFs-P catalyst comprises the following steps: S1: Zirconium nitrate with a mass ratio of 10-12:235-285 is mixed with N,N-dimethylformamide to form solution A, terephthalic acid with a mass ratio of 4-5:170-210 is mixed with N,N-dimethylformamide to form solution B, solution B is added dropwise into solution A, and the mixture is reacted at 120℃ for 24 hours, then centrifugal washing and vacuum drying at 60℃ are performed to obtain UiO-66 carrier; S2: N,N-dimethylacetamide, UiO-66 carrier, 4-bromobenzenesulfonic acid, triphenylphosphine, potassium carbonate, and tetrakis(triphenylphosphine)palladium are uniformly mixed in a mass ratio of 170-205:4-6:3-3.5:3.8-4.2:1-1.2:0.4-0.5, and the mixture is reacted at 110℃ under nitrogen protection for 18 hours, then washed and dried to obtain MOFs-P; S3: MOFs-P and anhydrous dichloromethane are mixed in a mass ratio of 3-4:200-240 to form solution C, AlCl3 and anhydrous dichloromethane are mixed in a mass ratio of 48-52:80-85 to form solution D, solution D is added dropwise into solution C at -5-5℃, and the mixture is stirred and reacted for 6 hours, then centrifugal separation and washing are performed, and the mixture is dried at 100℃ in a nitrogen environment for 6 hours to obtain IL@MOFs-P catalyst.

[0008] Preferably, in step 1, the molar ratio of γ-valerolactone, phosphorus oxychloride and diethylene glycol is 10:2:1.

[0009] Preferably, in step 2, the molar ratio of γ-valerolactone, propylene oxide and diethylene glycol in step 1 is 6:4:1.

[0010] Preferably, in step 2, the total mass of IL@MOFs-P catalyst added is 2% to 5% of the sum of the theoretical mass of the intermediate obtained in step 1 and the mass of propylene oxide.

[0011] Preferably, in step 5, the deionized water added each time during washing is 0.5 times the volume of the crude chloroalkyl polyphosphate product, and the mass of anhydrous sodium sulfate solid particles is 10% of the total mass of the chloroalkyl polyphosphate.

[0012] Preferably, in step 5, the vacuum drying conditions are: temperature 40-50℃, vacuum degree -0.1MPa, and drying time 2-4 hours.

[0013] Preferably, in step S2, the washing and drying process is: washing with N,N-dimethylacetamide and deionized water for 2 times respectively, and vacuum drying at 80℃ for 2 hours.

[0014] Preferably, in step S3, the washing conditions are: washing with anhydrous dichloromethane for 2 times.

[0015] After adopting the above technical solutions, the application has the following advantages: 1. The application uses γ-valerolactone as a solvent, which has polar aprotic properties that can simultaneously dissolve polar and nonpolar substances, low hygroscopicity, can effectively avoid the risk of hydrolysis of phosphorus oxychloride in water, high boiling point and high heat capacity characteristics can buffer the reaction heat release, reduce the side reactions caused by local overheating, and facilitate efficient recovery after reaction by distillation, and after refining, the solvent can be recycled, reducing production costs and environmental pollution.

[0016] 2. The application uses IL@MOFs-P catalyst, which provides high specific surface area through zirconium-based MOFs porous carrier, enhances the adsorption and mass transfer efficiency of reactants, and promotes the ring-opening and addition reactions of propylene oxide through the synergistic effect of active sites coordinated with metal ions and sulfonic acid groups, thereby improving the catalytic activity and selectivity; the catalyst can be recovered and reused after washing and drying, solving the problems of traditional catalysts such as fast deactivation and difficult recovery.

[0017] 3. In the reaction process, the reaction temperature, stirring rate and raw material adding method are precisely controlled, the hydrolysis of phosphorus oxychloride is inhibited by low temperature and slow feeding in step 1, the catalyst is activated at high temperature and nitrogen is introduced to isolate oxygen in step 2, so as to reduce the occurrence of side reactions; in the post-processing process, impurities and water are effectively removed by distillation, centrifugation, water washing and vacuum drying, and the purity of the final product can reach more than 98%, and the yield is significantly improved.

[0018] 4. The whole process realizes the recycling of solvent and catalyst, the solvent is refined by activated carbon adsorption, the catalyst is regenerated by nitrogen blowing, the "three wastes" emission is reduced, which meets the green chemistry concept; at the same time, the reaction parameters are optimized to reduce energy consumption, improve production efficiency, and have good industrial application prospect. DETAILED DESCRIPTION

[0019] The features and exemplary embodiments of various aspects of the present application will be described in detail below, in order to make the purposes, technical solutions and advantages of the present application more clear and apparent, the present application will be further described in detail below in combination with specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present application, and are not configured to limit the present application. For those skilled in the art, the present application can be implemented without some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by showing examples of the present application.

[0020] The present application provides a preparation method of chloroalkyl polyphosphate, which mainly comprises the following steps: Step 1 Diethylene glycol is added to γ-valerolactone solvent to form a mixed solution, the mixed solution is added to a glass reaction kettle with stirring and tail gas absorption device, phosphorus oxychloride is slowly added to the above-mentioned reaction kettle, the temperature is raised to 20-50℃, the reaction time lasts for 2-3 hours, the stirring is continued during the reaction, the stirring rate is controlled at 200-300r / min, the generated hydrogen chloride gas is absorbed and treated by the tail gas absorption device during the reaction, and the reaction is completed. After the reaction, an intermediate-containing reaction solution is obtained.

[0021] In the above step, the molar ratio of γ-valerolactone, phosphorus oxychloride and diethylene glycol added is 10:2:1.

[0022] In the above step, the addition time of phosphorus oxychloride is 5-10 min.

[0023] In the above step, the reaction raw materials for generating intermediates by reaction of diethylene glycol and phosphorus oxychloride are as follows:

[0024] In the above reaction process, the hydroxyl oxygen atom in diethylene glycol attacks the chlorine atom connected to the phosphorus atom in phosphorus oxychloride, a nucleophilic substitution occurs, the chlorine atom is replaced by an alkoxy group, and hydrogen chloride is released, forming an intermediate containing a phosphorus-oxygen-carbon bond, which builds the initial phosphorus-oxygen skeleton.

[0025] In the above reaction process, γ-valerolactone is used as the solvent. The reason is that γ-valerolactone is a polar aprotic solvent that has good solubility for both polar and nonpolar substances. It has low hygroscopicity, which can ensure that the reaction is carried out in a low water environment, avoiding the risk of violent hydrolysis of phosphorus oxychloride when it comes into contact with water.

[0026] In addition, the boiling point of γ-valerolactone is about 207℃, which is quite different from the boiling points of the reactants phosphorus oxychloride and diethylene glycol. Therefore, it is convenient to recycle γ-valerolactone after the reaction is completed. In addition, the above reaction process releases a large amount of heat, and the high heat capacity and high boiling point of γ-valerolactone can effectively buffer the heat release, avoiding side reactions caused by local overheating.

[0027] In the above step, the temperature is controlled at 20-50℃, and phosphorus oxychloride is added slowly, which can control the reaction rate and the temperature balance of the system, avoiding local overheating that leads to hydrolysis of phosphorus oxychloride or intensification of side reactions. In addition, the above temperature range can ensure a faster reaction rate, improving the efficiency of the reaction.

[0028] Step 2 To the reaction solution obtained in step 1, γ-valerolactone and IL@MOFs-P catalyst are added, then propylene oxide is slowly added, the addition time is 10-12 min, after the addition is completed, the reaction kettle is heated to 130-150℃, nitrogen is continuously introduced into the reaction kettle, the stirring rate is maintained at 300-400 r / min during the reaction, the reaction time is controlled at 4-6 hours, after the reaction is completed, a mixed solution containing the final target product chloroalkyl polyphosphate is obtained.

[0029] In the above step, the molar ratio of γ-valerolactone, propylene oxide and diethylene glycol in step 1 is 6:4:1.

[0030] In the above step, the total mass of IL@MOFs-P catalyst added is 2%-5% of the sum of the theoretical mass of the intermediate obtained in step 1 and the mass of propylene oxide.

[0031] In the above reaction process, the temperature in the reaction kettle needs to be kept stable, and the temperature fluctuation should not exceed 1℃ / min.

[0032] In the above step, the intermediate obtained in step 1 reacts with propylene oxide under the action of IL@MOFs-P catalyst to produce ring-opening addition reaction, and the reaction principle is as follows:

[0033] The three-membered ring structure of propylene oxide has high strain. The epoxy bond of propylene oxide is affected by the induction and polarization of the epoxy bond by the phosphorus-containing structure in the intermediate. Under the action of the active site of the catalyst, ring opening occurs. The chlorine atom connected to the phosphorus in the intermediate is replaced by the alkoxy group after the ring opening of propylene oxide, forming the main chain structure of chloroalkyl polyphosphate.

[0034] In the above steps, adding additional γ-valerol can further adjust the polarity of the system, ensuring that the reaction proceeds efficiently and rapidly.

[0035] During the above reaction process, the temperature fluctuation does not exceed 1℃ / min. The ring-opening reaction of propylene oxide is sensitive to temperature. A stable temperature can ensure the selectivity of the reaction and reduce side reactions such as cross-linking and chain scission.

[0036] During the above reaction process, the temperature of the system is controlled at 130-150℃. Within this temperature range, the active sites of the catalyst can be effectively activated, promoting the ring-opening reaction of propylene oxide. Maintaining a stirring rate of 300-400 r / min during the reaction can enhance the three-phase mass transfer of gas, liquid, and solid. Sufficient contact between the liquid reactants and the solid catalyst can promote the increase of the reaction rate. Nitrogen can effectively isolate oxygen, preventing catalyst oxidation and deactivation, and product oxidation and degradation.

[0037] The preparation method of the IL@MOFs-P catalyst in the above steps is as follows: S1, Synthetic zirconium-based MOFs support Zirconium nitrate was dissolved in N,N-dimethylformamide and stirred until clear to prepare solution A for later use; terephthalic acid was dissolved in N,N-dimethylformamide and stirred until a suspension was formed to prepare solution B for later use.

[0038] Solution B was slowly added dropwise to solution A, stirred for 30 min, transferred to a polytetrafluoroethylene reactor, and reacted at 120 °C for 24 hours. After that, the mixture was naturally cooled to room temperature. The mixture was then centrifuged and washed twice each with N,N-dimethylformamide and methanol. After drying under vacuum at 60 °C for 2 hours, UiO-66 powder was obtained for later use.

[0039] In solution A, the mass ratio of zirconium nitrate to N,N-dimethylformamide is 10–12:235–285; in solution B, the mass ratio of terephthalic acid to N,N-dimethylformamide is 4–5:170–210.

[0040] This step involves reacting zirconium nitrate with terephthalic acid via a solvothermal reaction to form UiO-66 crystal powder with a porous structure. Its high specific surface area and regular channels provide sufficient active sites for subsequent modification, adsorbing and enriching the reactants, thereby promoting the reaction.

[0041] In addition, multiple washing of the UiO-66 crystal powder can effectively remove unreacted raw materials and impurities, and finally vacuum drying at 60°C can help maintain the crystal structure and avoid collapse of the crystal structure.

[0042] S2, graft modification The UiO-66 powder is dispersed in N,N-dimethylacetamide, 4-bromobenzenesulfonic acid, triphenylphosphine, potassium carbonate, and tetrakis(triphenylphosphine)palladium are added, and stirring is carried out under a nitrogen protective atmosphere at 110°C for 18 hours. Then, N,N-dimethylacetamide and deionized water are used for washing respectively for 2 times, and vacuum drying is carried out at 80°C for 2 hours to obtain the UiO-66-PPh2-C6H4-SO3H intermediate, which is denoted as MOFs-P.

[0043] In the above process, the mass ratio of N,N-dimethylacetamide, UiO-66 powder, 4-bromobenzenesulfonic acid, triphenylphosphine, potassium carbonate, and tetrakis(triphenylphosphine)palladium is 170-205:4-6:3-3.5:3.8-4.2:1-1.2:0.4-0.5.

[0044] This process grafts functional groups such as 4-bromobenzenesulfonic acid onto the surface of the UiO-66 crystal through a coupling reaction, introduces sulfonic acid groups (-SO3H) and phosphine ligands (-PPh2) on the surface layer of the UiO-66 crystal, thereby endowing the carrier with acidic sites and coordination ability, and significantly enhancing its ability to load ions.

[0045] In addition, nitrogen protection is used throughout the above process to prevent the catalyst from being oxidized and losing activity.

[0046] S3, loading anchoring MOFs-P is dispersed in anhydrous dichloromethane, denoted as solution C for standby; and AlCl3 is dispersed in anhydrous dichloromethane, denoted as solution D for standby.

[0047] A small amount of solution D is slowly added to solution C at -5-5°C, and after the addition is completed, the temperature is restored to room temperature, stirring is carried out for 6 hours, centrifugal separation is carried out and washing is carried out with anhydrous dichloromethane for 2 times, and then it is transferred to a nitrogen environment at 100°C for static drying for 6 hours to obtain the IL@MOFs-P catalyst.

[0048] In the above process, the mass ratio of MOFs-P and anhydrous dichloromethane in solution C is 3-4:200-240; and the mass ratio of AlCl3 and anhydrous dichloromethane in solution D is 48-52:80-85.

[0049] In the above process, the mass ratio of solution D and solution C is 10-15:205-245.

[0050] In the process, AlCl3 coordinates with the functional groups on the surface of MOFs-P to form an ionic liquid active center and anchor on the MOFs carrier.

[0051] AlCl3 can interact with other components in the system to further adjust the electron cloud density and spatial structure of the active site; after coordination with the functional groups on the surface of MOFs-P, it can enhance the adsorption capacity and activation effect of the active site on the reactants, optimize the transition state structure of the reaction, reduce the activation energy of the reaction, thereby improving the activity and selectivity of the catalyst, and promoting the generation of chloroalkyl polyphosphates.

[0052] The above reaction process is carried out in a low temperature environment of-5-5℃, which can effectively reduce the hydrolysis reaction of AlCl3, and the catalyst site can be effectively activated by standing in a nitrogen environment, thereby synergistically improving the reaction selectivity and efficiency of the porous structure and active center of the catalyst.

[0053] In summary, the zirconium-based MOFs carrier has a porous structure, which provides a large specific surface area for the reaction; on the one hand, a large number of active sites can be loaded on the surface of the carrier's pores, increasing the number of active sites; on the other hand, the porous structure is beneficial to the diffusion of reactants and products.

[0054] During the reaction process, intermediates and propylene oxide can quickly diffuse into the pores and fully contact with the active sites to react; the chloroalkyl polyphosphates generated by the reaction can also diffuse out of the pores in time, avoiding the accumulation of products on the active sites, thereby reducing the inhibitory effect of the products on the reaction and ensuring the efficient progress of the catalytic reaction.

[0055] In addition, the metal ions and organic ligands in the IL@MOFs-P catalyst together constitute a rich active site, and the metal ions such as zirconium on the active site of the catalyst can coordinate with the oxygen atoms in the propylene oxide molecules, causing the electron cloud distribution of the propylene oxide molecules to change, further increasing the ring tension; and the acidic sites such as sulfonic acid groups can provide protons to electrophilically attack the three-membered ring of propylene oxide, promoting the ring-opening of propylene oxide.

[0056] The active groups in the intermediates also interact with the active sites of the catalyst, allowing the intermediates and propylene oxide to effectively adsorb and enrich on the surface of the catalyst, increasing the collision probability between them and thereby accelerating the reaction.

[0057] Therefore, the IL@MOFs-P catalyst increases the active sites through the porous structure, promotes the full contact of the reactants, reduces the activation energy of the reaction through the coupling of specific metal ions and groups, promotes the ring-opening reaction and addition reaction of propylene oxide, and thereby effectively improves the production efficiency of the target product chloroalkyl polyphosphates.

[0058] Step 3 The mixture containing the final target product chloroalkyl polyphosphate obtained in step 2 is transferred to a normal pressure distillation column, and the distillation column temperature is set to 210-215°C to perform distillation separation of γ-valerolactone. The γ-valerolactone is recovered at the top, and the mixture of IL@MOFs-P catalyst and the target product chloroalkyl polyphosphate remains in the distillation column.

[0059] In the above step, the solvent and the reaction system are separated by normal pressure distillation under the condition of 210-215°C, taking advantage of the boiling point difference between γ-valerolactone and the product. This step can efficiently recover the solvent, reduce production costs, and lay the foundation for subsequent product purification.

[0060] Step 4 The γ-valerolactone recovered at the top is adsorbed by activated carbon for 1-2h to obtain refined γ-valerolactone, which is then transported to steps 1 and 2 for recycling.

[0061] In this step, the γ-valerolactone recovered by distillation may contain trace amounts of impurities. Activated carbon adsorption can remove organic impurities and pigments, improving the purity of the solvent.

[0062] In addition, the solvent after refining is recycled for steps 1 and 2, achieving resource recycling and reducing production costs while reducing the discharge of "three wastes" and better meeting the concept of green chemistry.

[0063] Step 5 The mixture of IL@MOFs-P catalyst and the target product chloroalkyl polyphosphate remaining in the distillation column is centrifuged to obtain a solid catalyst and a chloroalkyl polyphosphate crude product.

[0064] The separated IL@MOFs-P catalyst is washed with γ-valerolactone for 2-3 times and then purged with nitrogen for 2 hours at 120°C.

[0065] The separated chloroalkyl polyphosphate crude product is washed with deionized water for 2 times. After water washing, the aqueous phase is removed, anhydrous sodium sulfate solid particles are added to the remaining liquid, and after standing for 12 hours, the anhydrous sodium sulfate solid particles are removed by filtration. Then, the remaining chloroalkyl polyphosphate is transferred to an environment with a temperature of 40-50°C and a vacuum degree of -0.1 MPa for drying for 2-4 hours to obtain the final product chloroalkyl polyphosphate.

[0066] Wherein, the deionized water added each time is 0.5 times the volume of the chloroalkyl polyphosphate crude product.

[0067] Wherein, the mass of the added anhydrous sodium sulfate solid particles is 10% of the total mass of the chloroalkyl polyphosphate.

[0068] In the above process, the physical separation of the solid catalyst and the liquid product is achieved by centrifugal separation, and then the soluble impurities and water in the product are removed by water washing and drying, so as to obtain the target product with high purity.

[0069] In the treatment process of the catalyst, the residual product and impurities on the surface of the catalyst are removed by washing the catalyst with γ-valerolactone for 2-3 times, and the surface active sites are recovered by blowing nitrogen at 120℃ for 2 hours, so as to create conditions for recycling.

[0070] In the purification process of the final product chloroalkyl polyphosphate, the water-soluble impurities in the system are removed by washing with deionized water for 2 times, and the excess deionized water is avoided to increase the drying energy consumption in the subsequent process by using 0.5 times the volume of deionized water; the residual water can be fully adsorbed by using sufficient anhydrous sodium sulfate desiccant, so as to ensure the drying effect; finally, vacuum drying is carried out at 40-50℃, so as to avoid the decomposition of the product and efficiently remove the residual water, and ensure the purity and stability of the product.

[0071] In order to facilitate further understanding of the present application, several embodiments and comparative examples of the present application are given below.

[0072] Example 1 The present embodiment provides a preparation method of chloroalkyl polyphosphate, which specifically comprises the following steps: I. Preparation of catalyst S1, synthesis of zirconium-based MOFs carrier 20g of zirconium nitrate was dissolved in 500g of N,N-dimethylformamide, and stirred until clear to form solution A for standby; 10g of terephthalic acid was dissolved in 380g of N,N-dimethylformamide, and stirred to form a suspension liquid to form solution B for standby.

[0073] Solution B was slowly added to solution A, stirred for 30min, and then transferred to a polytetrafluoroethylene reaction kettle. After reaction at 120℃ for 24 hours, it was naturally cooled to room temperature; centrifugal separation was carried out, and then washed with N,N-dimethylformamide and methanol for 2 times respectively, and vacuum dried at 60℃ for 2 hours to obtain UiO-66 powder for standby.

[0074] S2, graft modification Take 15 g of UiO-66 powder dispersed in 540 g of N, N-dimethylacetamide, add 10 g of 4-bromobenzenesulfonic acid, 12 g of triphenylphosphine, 3.5 g of potassium carbonate, 1.5 g of tetrakis(triphenylphosphine)palladium, stir the reaction at 110°C under nitrogen atmosphere for 18 hours, wash with N, N-dimethylacetamide and deionized water respectively for 2 times, and vacuum dry at 80°C for 2 hours to obtain the UiO-66-PPh2-C6H4-SO3H intermediate, denoted as MOFs-P.

[0075] S3, load anchor Take 20 g of MOFs-P dispersed in 1000 g of anhydrous dichloromethane, denoted as solution C for standby; take 50 g of AlCl3 dispersed in 85 g of anhydrous dichloromethane, denoted as solution D for standby.

[0076] According to the mass ratio of 1:14 of solution D and solution C, slowly add solution D to solution C at -5-5°C, restore to room temperature after the addition is completed, stir for 6 hours, centrifugal separation and wash with anhydrous dichloromethane for 2 times, and transfer to a nitrogen environment at 100°C for 6 hours of drying to obtain the IL@MOFs-P catalyst.

[0077] II. Preparation of chloroalkyl polyphosphates Step 1 Add 1 mol of diethylene glycol to 10 mol of γ-valerolactone solvent and mix uniformly to form a mixed solution, add the mixed solution to a glass reaction kettle with stirring and tail gas absorption device, slowly add 2 mol of phosphorus oxychloride to the above reaction kettle, the addition time is 6 min, the temperature is raised to 40°C, and the reaction time is 2.5 hours, the stirring rate is controlled at 250 r / min during the reaction, and the generated hydrogen chloride gas is absorbed and treated by the tail gas absorption device during the reaction. After the reaction is completed, an intermediate-containing reaction solution is obtained.

[0078] Step 2 Add 6 mol of γ-valerolactone and 20 g of IL@MOFs-P catalyst to the reaction solution obtained in step 1, then slowly add 4 mol of propylene oxide, the addition time is 10 min, after the addition is completed, the reaction kettle is heated to 140°C, nitrogen is continuously introduced into the reaction kettle, the stirring rate is maintained at 350 r / min during the reaction, and the reaction time is controlled at 5 hours. After the reaction is completed, a mixed solution containing the final target product chloroalkyl polyphosphates is obtained.

[0079] Step 3 The mixture containing the final target product chloroalkyl polyphosphates obtained in step 2 is transferred to an atmospheric distillation column, and the distillation column temperature is set to 212°C to distill and separate γ-valerolactone, and the IL@MOFs-P catalyst and the target product chloroalkyl polyphosphates are recovered from the top of the distillation column.

[0080] Step 4 The γ-valerolactone recovered from the top of the column is adsorbed by activated carbon for 2 hours to obtain refined γ-valerolactone, which is recycled and used in steps 1 and 2.

[0081] Step 5 The mixture of IL@MOFs-P catalyst and target product chloroalkyl polyphosphates remaining in the distillation column is centrifuged to obtain a solid catalyst and a crude chloroalkyl polyphosphate.

[0082] The separated IL@MOFs-P catalyst is washed with γ-valerolactone for 3 times, and then nitrogen is blown for 2 hours at 120°C.

[0083] The separated crude chloroalkyl polyphosphate is washed with deionized water for 2 times, and then the water phase is removed. Anhydrous sodium sulfate solid particles are added to the remaining liquid at 10% of the total mass of chloroalkyl polyphosphate, and then filtered after standing for 12 hours. The remaining chloroalkyl polyphosphate is then dried in a 40°C, vacuum degree of -0.1 MPa environment for 3 hours to obtain the final product chloroalkyl polyphosphate.

[0084] Example 2 This example is based on example 1, and step 2 of the preparation of chloroalkyl polyphosphate is adjusted to reduce the amount of IL@MOFs-P catalyst, specifically: Step 2 6 mol of γ-valerolactone and 15 g of IL@MOFs-P catalyst are added to the reaction solution obtained in step 1, and then 4 mol of propylene oxide is slowly added for 10 min. After the addition is completed, the reaction kettle is heated to 140°C, and nitrogen is continuously introduced into the reaction kettle. The stirring rate is maintained at 350 r / min during the reaction, and the reaction time is controlled at 5 hours. After the reaction is completed, a mixture containing the final target product chloroalkyl polyphosphate is obtained.

[0085] The remaining steps are the same as example 1.

[0086] Example 3 This example is based on example 1, and the S2 step of the preparation of the catalyst is adjusted to adjust the addition amount of each component, specifically: S2, graft modification Take 15 g of UiO-66 powder dispersed in 540 g of N, N-dimethylacetamide, add 9 g of 4-bromobenzenesulfonic acid, 11.5 g of triphenylphosphine, 3 g of potassium carbonate, 1.2 g of tetrakis(triphenylphosphine)palladium, stir the reaction at 110°C under nitrogen atmosphere for 18 hours, wash with N, N-dimethylacetamide and deionized water respectively for 2 times, and vacuum dry at 80°C for 2 hours to obtain the UiO-66-PPh2-C6H4-SO3H intermediate, denoted as MOFs-P.

[0087] The remaining steps are exactly the same as Example 1.

[0088] Comparative Example 1 This comparative example is based on Example 1, and the S3 step of preparing the catalyst is adjusted. After centrifugal separation and washing, the IL@MOFs-P catalyst is directly obtained, specifically: S3, loading anchor Take 20 g of MOFs-P and disperse it in 1000 g of anhydrous dichloromethane, denoted as solution C for standby; take 50 g of AlCl3 and disperse it in 85 g of anhydrous dichloromethane, denoted as solution D for standby.

[0089] Solution D and solution C are mixed in a mass ratio of 1:14. Solution D is slowly added to solution C at -5-5°C. After the addition is completed, it is restored to room temperature and stirred for 6 hours. After centrifugal separation and washing with anhydrous dichloromethane for 2 times, the IL@MOFs-P catalyst is obtained.

[0090] The remaining steps are exactly the same as Example 1.

[0091] Comparative Example 2 This comparative example is based on Example 1, and the step 2 of preparing the chloroalkyl polyphosphate is adjusted. No additional γ-valerolactone is added to the reaction solution, specifically: Step 2 20 g of IL@MOFs-P catalyst is added to the reaction solution obtained in step 1, and then 4 mol of propylene oxide is slowly added. The addition time is 10 min. After the addition is completed, the reaction kettle is heated to 140°C, and nitrogen is continuously introduced into the reaction kettle. The stirring rate is maintained at 350 r / min during the reaction. The reaction time is controlled for 5 hours. After the reaction is completed, a mixed solution containing the final target product chloroalkyl polyphosphate is obtained.

[0092] The remaining steps are exactly the same as Example 1.

[0093] Comparative Example 3 The comparative example is based on Example 1, adjusting Step 5 of the process of preparing chloroalkyl polyphosphates, shortening the vacuum drying process of the final product chloroalkyl polyphosphate, specifically: Step 5 Centrifugal separation of the remaining IL@MOFs-P catalyst and the target product chloroalkyl polyphosphate mixture in the distillation column to obtain solid catalyst and chloroalkyl polyphosphate crude product.

[0094] The separated IL@MOFs-P catalyst is washed with γ-valerolactone for 3 times, then nitrogen blowing is carried out at 120°C for 2 hours.

[0095] The separated chloroalkyl polyphosphate crude product is washed with deionized water for 2 times, after water washing, the water phase is removed, 10% of the total mass of chloroalkyl polyphosphate anhydrous sodium sulfate solid particles are added to the remaining liquid, and after standing for 12 hours, the anhydrous sodium sulfate solid particles are removed by filtration to obtain the final product chloroalkyl polyphosphate.

[0096] The remaining steps are exactly the same as Example 1.

[0097] According to the above steps of the examples and comparative examples, chloroalkyl polyphosphate is prepared, after preparation, the yield and purity of chloroalkyl polyphosphate are detected and calculated, the purity and recovery rate of the solvent γ-valerolactone are detected and calculated, and the activity of the recovered catalyst is detected, and the data are recorded and counted as follows:

[0098] Based on the above data, the following conclusions can be drawn: According to the data comparison of Example 1 and Example 3, Comparative Example 1, the influence of the catalyst can be known.

[0099] In Example 3, the amount of grafting modification raw materials is reduced by about 10% of 4-bromobenzenesulfonic acid and 4.2% of triphenylphosphine, which will result in insufficient functional group density on the surface of the carrier, reducing the number of active sites, thus weakening the adsorption and enrichment effect of the reactants, and reducing the final yield of the product by 2.4%.

[0100] In Comparative Example 1, the high-temperature standing drying process in a nitrogen environment is omitted, which makes AlCl3 not completely form stable ionic liquid sites with the sulfonic acid groups of MOFs-P, reduces the activation ability of propylene oxide in the reaction process, and leads to a decrease in catalyst activity. The unactivated catalyst surface will also be blocked by solvent molecules, further affecting the reaction.

[0101] According to the data comparison of Example 1 and Example 2 and Comparative Example 2, the influence of the process conditions can be known.

[0102] The amount of catalyst used in Example 2 was changed from 20 g to 15 g, a 25% reduction in usage, resulting in a 4.2% reduction in final yield of product, indicating that reducing the amount of catalyst used has some impact on the final completion of the reaction, but since there is a minimum effective load of catalyst, the reaction rate improves limitedly when the amount of catalyst is excessive, so the impact on the final yield is limited.

[0103] In Comparative Example 2, no additional γ-valerolactone was added, resulting in insufficient polarity of the system, which reduced the mass transfer efficiency of the intermediate and propylene oxide, and insufficient mixing of the gas-liquid-solid three-phase mixture, which increased the side reactions and reduced the final product yield by 8.8%.

[0104] According to the data comparison of Example 1 and Comparative Example 3, the influence of post-processing can be known.

[0105] In Comparative Example 3, the vacuum drying step was omitted, resulting in a sharp increase in the moisture content of the product and a significant decrease in the purity, indicating that vacuum drying is the core of moisture control, and using anhydrous sodium sulfate only adsorbs free water, while the vacuum environment can remove bound water to avoid product hydrolysis and deterioration.

[0106] In accordance with the above embodiments of the present application, these embodiments do not exhaustively describe all the details and are not limited to only the specific embodiments. Obviously, according to the above description, many modifications and changes can be made. The present description selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can well utilize the present application and make modifications and uses on the basis of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A process for the preparation of chloroalkyl polyphosphates, characterized in that, The method comprises the following steps: Step 1: A mixture of diethylene glycol and gamma-valerolactone solvent is added to a glass reaction kettle with stirring and tail gas absorption device, phosphorus oxychloride is added, the addition time is 5-10 min, the temperature is raised to 20-50 DEG C, and the reaction is carried out for 2-3 hours, the stirring is continued during the reaction, and the generated hydrogen chloride gas is absorbed and treated to obtain a reaction liquid containing an intermediate; Step 2: To the reaction liquid of step 1, gamma-valerolactone and IL@MOFs-P catalyst are added, propylene oxide is added, the addition time is 10-12 min, the reaction kettle is heated to 130-150 DEG C, nitrogen is continuously introduced, the stirring rate is 300-400 r / min, and the reaction is carried out for 4-6 hours to obtain a mixed liquid containing chloroalkyl polyphosphate; Step 3: The mixed liquid obtained in step 2 is transferred to an atmospheric distillation column for distillation separation, the distillation column temperature is 210-215 DEG C, and gamma-valerolactone recovery liquid and chloroalkyl polyphosphate mixed liquid containing IL@MOFs-P catalyst are obtained; Step 4: The recovered gamma-valerolactone is refined by activated carbon adsorption for 1-2 h and then transported to steps 1 and 2 for recycling; Step 5: The mixed liquid in step 3 is centrifuged to obtain a solid catalyst and a chloroalkyl polyphosphate crude product; The IL@MOFs-P catalyst is washed with gamma-valerolactone for 2-3 times, and then nitrogen is blown at 120 DEG C for 2 hours; The chloroalkyl polyphosphate crude product is washed with deionized water for 2 times, the water phase is removed, anhydrous sodium sulfate solid particles are added, the mixture is left to stand for 12 hours, the filtrate is obtained by filtration, and the final product is obtained by vacuum drying.

2. The method according to claim 1, wherein the preparation method of the IL@MOFs-P catalyst in step 2 comprises the following steps: S1: Zirconium nitrate with a mass ratio of 10-12:235-285 is mixed with N,N-dimethylformamide to prepare solution A, terephthalic acid with a mass ratio of 4-5:170-210 is mixed with N,N-dimethylformamide to prepare solution B, solution B is added dropwise into solution A, and the mixture is reacted at 120 DEG C for 24 hours, then centrifuged, washed and dried at 60 DEG C under vacuum to obtain a UiO-66 carrier; S2: N,N-dimethylacetamide, the UiO-66 carrier, 4-bromobenzenesulfonic acid, triphenylphosphine, potassium carbonate and tetrakis(triphenylphosphine)palladium are uniformly mixed at a mass ratio of 170-205:4-6:3-3.5:3.8-4.2:1-1.2:0.4-0.5, and the mixture is reacted at 110 DEG C under nitrogen protection for 18 hours to obtain MOFs-P after washing and drying. ​ S3: MOFs-P and anhydrous dichloromethane were prepared into a solution C with a mass ratio of 3-4:200-240, AlCl3 and anhydrous dichloromethane were prepared into a solution D with a mass ratio of 48-52:80-85, according to the ratio of solution D:solution C=10-15:205-245, solution D was added dropwise into solution C at-5-5℃, stirring reaction for 6 hours, centrifugal separation and washing, and then drying at 100℃ in a nitrogen environment for 6 hours to obtain the IL@MOFs-P catalyst.

3. The method according to claim 1, wherein, In step 1, the molar ratio of γ-valerolactone, phosphorus oxychloride and diethylene glycol is 10:2:

1.

4. The method according to claim 1, wherein, In step 2, the molar ratio of γ-valerolactone, propylene oxide and diethylene glycol in step 1 is 6:4:

1.

5. The method according to claim 1, wherein, In step 2, the total mass of IL@MOFs-P catalyst added is 2%-5% of the total mass of the intermediate obtained in step 1 and propylene oxide.

6. The method according to claim 1, wherein, In step 5, the deionized water added each time is 0.5 times the volume of the crude chloroalkyl polyphosphates, and the mass of anhydrous sodium sulfate solid particles is 10% of the total mass of chloroalkyl polyphosphates.

7. The method according to claim 1, wherein, In step 5, the vacuum drying conditions are: temperature 40-50℃, vacuum degree-0.1MPa, and drying time 2-4 hours.

8. The method according to claim 2, wherein, In step S2, the washing and drying process is: washing with N,N-dimethylacetamide and deionized water for 2 times respectively, and vacuum drying at 80℃ for 2 hours.

9. The method according to claim 2, wherein, In step S3, the washing conditions are: washing with anhydrous dichloromethane for 2 times.

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