A method for preparing hydroxyl- or epoxy-containing organic phosphate from epoxy compounds

Abstract

The present invention relates to a method for preparing a hydroxyl- or epoxy-group-containing organic phosphate from an epoxy compound, comprising the following steps: mixing a P(O)-OH compound and an epoxy compound under air, stirring for reaction, cooling, and purifying to obtain a hydroxyl- or epoxy-group-containing organic phosphate as shown in Formula I, wherein the epoxy compound is one of epichlorohydrin, methylepichlorohydrin, oxetane, and cyclohexene oxide, and the epoxy compound serves as both a reaction substrate and a reaction solvent; R 1 、R 2 are selected from one or two of aryl, substituted aryl, aliphatic, ether, hydroxyl and hydrogen atoms; R 3 The present invention provides a method for preparing an organophosphate compound directly from a P(O)-OH compound and an epoxy compound under solvent-free and additive-free conditions. The raw materials are inexpensive, readily available, green and stable, with high atom economy. The reaction conditions are simple and mild, and the reaction can be carried out efficiently without any additives.

Description

Technical Field

[0001] The present invention relates to the field of organic synthesis, and in particular to a method for preparing organic phosphate containing hydroxyl or epoxy groups from epoxy compounds. Background Art

[0002] Organic acid ester compounds are widely used in flame retardants, biomedicine, battery materials and many other fields. Benin et al. disclosed several epoxy-structured organic phosphates with flame retardant properties, among which organic phosphates containing alkylated phosphate groups can more effectively reduce heat release than cyclic phosphate groups (Benin V, Cui X, Morgan AB, et al. Journal of Applied Polymer Science, 2015, 132(30), 42296.). Chinese patents CN104844789 A and CN 106188499 A respectively disclose the introduction of phosphate groups as flame retardant groups into polymer monomers to synthesize highly flame-retardant and highly stable resin materials. Lauth found that organic phosphates containing epoxy groups on the phosphate group showed irreversible inhibition of glyceraldehyde-3-phosphate dehydrogenase GAPDH (Lauth N, Alric I, Willson M, et al. Phosphorus, Sulfur, and Silicon and the Related Elements, 1993, 76 (1-4): 155-158.). Muralidharan et al. disclosed an oxirane-containing organic phosphate that can be used for solid polymer electrolyte monomers (Babu HV, Muralidharan K. Polymer, 2014, 55 (1): 83-94.). Recently, they synthesized an organic phosphate polymer with potential application prospects in the field of optical materials with tunable refractive index (Othayoth AK, Srinivas B, Murugan K, et al. Optical Materials, 2020, 104: 109841.).

[0003] Currently, organophosphates containing epoxy structures are mainly prepared by reacting a phosphorus-halogen reagent with an alcohol containing an epoxy structure. This involves dropping the alcohol into a tetrahydrofuran solution of the phosphorus-halogen reagent at 0°C, and then slowly adding a base to the reaction system at 0°C to promote the formation of a PO bond to prepare the corresponding organophosphate (Babu HV, Muralidharan K. Polymer, 2014, 55(1):83-94). Benin et al. used the Michaelis–Arbuzov reaction to react a brominated epoxy compound with a trivalent phosphite at 135°C to obtain an organic phosphate containing an epoxy structure with a yield of 35%. However, the reaction efficiency was low. They also used a P(O)H compound to synthesize an organic phosphate with a similar structure through a multi-step reaction. The P(O)H compound first reacted with allyl bromide to form an allyl phosphite, and then the alkenyl group was oxidized to an epoxy structure to achieve the synthesis of an organic phosphate containing an epoxy structure. However, the conditions were relatively harsh and the reaction efficiency was low (Benin V, Cui X, Morgan AB, et al. Journal of Applied Polymer Science, 2015, 132(30), 42296.).

[0004] The above method has the following shortcomings: ① Phosphorus halide reagents are highly toxic, sensitive to water and oxygen, and have poor functional group compatibility; ② Alcohols containing epoxy structures are relatively expensive, the economic cost of the reaction is high, and it is not conducive to industrialization; ③ Some reaction preparation steps are relatively complex, the conditions are harsh, and the yield is low.

[0005] In view of the shortcomings of the above research methods, it is necessary to provide a new method for synthesizing epoxy group-containing organophosphate compounds that is simple, efficient, economical, environmentally friendly and has potential application value. Summary of the Invention

[0006] In response to the shortcomings of the prior art, the present invention aims to provide a method for preparing hydroxyl- or epoxy-containing organic phosphates from epoxy compounds. The preparation process is simple, does not require additional solvents and additives, and can achieve an efficient reaction using only reaction substrates. The reaction conditions are mild, and the product yield is high. The enrichment of epoxy ring-opening products or dechlorination products can be achieved by simply controlling the reaction temperature and stirring speed, and the method has good industrial application value.

[0007] To achieve the above object, the technical solution of the present invention is as follows:

[0008] The present invention provides a method for preparing an organic phosphate containing a hydroxyl group or an epoxy group from an epoxy compound, comprising the following steps:

[0009] Under air, a P(O)-OH compound and an epoxy compound are mixed, stirred for reaction, cooled, and purified to obtain a hydroxyl- or epoxy-containing organic phosphate as shown in Formula I:

[0010]

[0011] The epoxy compound is one of epichlorohydrin, methyl epichlorohydrin, oxetane, and cyclohexene oxide, and the epoxy compound serves as both a reaction substrate and a reaction solvent;

[0012] The structural formula of the P(O)-OH compound is shown in Formula II below:

[0013]

[0014] The R 1 、R 2 are selected from one or two of aryl, substituted aryl, aliphatic, ether, hydroxyl and hydrogen atoms;

[0015] The R 3 It is a hydrocarbon group containing an epoxy structure or other substituents.

[0016] Preferably, the mixing molar ratio of the P(O)-OH compound to the epoxy compound is 1:5-60.

[0017] Preferably, the P(O)-OH compound is one of diphenylphosphoric acid, dialkylphosphoric acid, phosphorous acid and hypophosphorous acid.

[0018] Preferably, the stirring reaction conditions are: at room temperature to 160° C., a stirring speed of 300 to 600 r / min, and a reaction time of 2 to 24 hours.

[0019] Preferably, when the stirring reaction temperature is room temperature to 140° C., the stirring speed is 300 to 400 r / min, and the yield of the epoxy ring-opening product in the reaction product is greater than 80%.

[0020] Preferably, when the stirring reaction temperature is 120-160° C., the stirring speed is 400-600 r / min, and the yield of the dechlorination product in the reaction product is greater than 70%.

[0021] Preferably, the purification process is: concentrating the reaction solution by vacuum distillation to obtain a crude product, and separating the crude product by column chromatography to obtain a dechlorinated product; or volatilizing the reaction solution at room temperature or recrystallizing it using n-hexane or dichloromethane to obtain a ring-opening product.

[0022] The synthesis reaction formula of the organic phosphate compound synthesized from the P(O)-OH compound and the epoxy compound provided by the present invention is shown in Formula III:

[0023]

[0024] The specific steps for synthesizing an organic phosphate compound from a P(O)-OH compound and an epoxy compound are as follows:

[0025] (1) Under air, place a P(O)-OH compound and an epoxy compound in a reaction vessel and mix them;

[0026] (2) In air, at a reaction temperature of room temperature to 160°C, stir the reaction at 300 to 600 rpm for 2 to 24 hours, and cool to room temperature after the reaction is completed;

[0027] (3) The solvent is removed by distillation under reduced pressure to obtain a crude product of the organic phosphate compound.

[0028] (4) The crude product is subjected to column chromatography to obtain a dechlorinated product; a portion of the crude product is evaporated at room temperature or recrystallized using n-hexane or dichloromethane to obtain a ring-opening product.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The present invention provides a method for preparing an organophosphate compound directly using a P(O)-OH compound and an epoxy compound as raw materials. The reaction conditions are very simple and mild, and the reaction can be carried out efficiently without any additives. The yield of the product can reach as high as 90% or more. At the same time, the selectivity of the reaction can be changed by controlling the temperature, stirring speed, reaction concentration, and reaction time in the preparation method, so that a dechlorinated product or a ring-opened product can be obtained in high yields. The yield of the epoxy ring-opened product obtained by reacting at 40-140°C for 2-12 hours is 80% or more, and the yield of the dechlorinated product obtained by heating at 120-160°C for 12-24 hours is as high as 70% or more. Both the dechlorinated product and the ring-opened product can be used in the flame retardant field. The dechlorinated product is an organophosphate containing an epoxy structure, which can be used as a polymerization monomer in the battery field or directly as a bioinhibitor, etc., and has broad application prospects.

[0031] 2. In the preparation method provided by the present invention, the epoxy compound can serve as both a reaction substrate and a solvent in the reaction system, which overcomes the limitation of requiring additional solvents in conventional reactions. At the same time, the epoxy compound also has the function of promoting the forward progress of the synthesis reaction. Therefore, the preparation method can be carried out efficiently without the need for additives. In the reaction, the phosphoric acid compound first undergoes a ring-opening reaction with the epoxy structure to obtain a ring-opening product, and the hydroxyl group and the chlorine atom of the ring-opening product undergo an intramolecular cyclization reaction to obtain a dechlorinated product. The reaction conditions are simple; no solvents or additives are required, the reaction solution components are simple, and the post-processing and purification steps of the reaction can be simplified to the greatest extent. The crude product can be obtained by simply concentrating the reaction solution or volatilizing and crystallizing at room temperature. The crude product is then subjected to chromatographic separation and purification to obtain the organophosphate compound product.

[0032] 3. The P(O)-OH compound used in this preparation method is cheap, readily available, green and stable, and has higher atom economy compared to the traditional method using P(O)Cl as a raw material. Epoxide compounds are cheap and stable, commonly used in industry to prepare polymers, and are readily available. At the same time, this reaction also has the advantages of broad functional group compatibility and efficient reaction with a variety of epoxy compounds, which is conducive to industrial promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 This is the H NMR spectrum of 2-oxiranylmethyldiphenylphosphinate obtained in Example 1;

[0035] Figure 2 This is the H NMR spectrum of 1-chloro-3-hydroxypropane-2-diphenylphosphinate obtained in Example 2;

[0036] Figure 3 This is the H NMR spectrum of (2-methyloxiranyl)methyldiphenylphosphinate obtained in Example 3;

[0037] Figure 4 This is the H NMR spectrum of 1-chloro-3-hydroxy-2-methylpropane-2-yl diphenylphosphinate obtained in Example 4;

[0038] Figure 5 This is the H NMR spectrum of [3-chloro-2-(chloromethyl)-2-(hydroxymethyl)propyl]diphenylphosphinate obtained in Example 5.

[0039] Figure 6 This is the H NMR spectrum of 2-oxiranylmethylbis(2,4,4-trimethylpentyl)phosphinate obtained in Example 6;

[0040] Figure 7 This is the H NMR spectrum of 1-chloro-3-hydroxypropane-2-bis(2,4,4-trimethylpentyl)phosphinate obtained in Example 7;

[0041] Figure 8 This is the H NMR spectrum of 2-hydroxycyclohexyldiphenylphosphinate obtained in Example 8. DETAILED DESCRIPTION

[0042] The present invention will be further described below with reference to specific examples. These examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0043] Example 1

[0044] This embodiment provides a method for preparing 2-oxiranylmethyl diphenylphosphinate, which is as follows:

[0045] Under air, 0.5 mmol of diphenylphosphoric acid and 2.0 mL of epichlorohydrin were added to the reactor. After sealing the tube, the mixture was heated to 120°C and stirred at 600 r / min for 24 h. The reaction was stopped and cooled to room temperature. The solvent was removed by distillation under reduced pressure. The crude product was separated by column chromatography to obtain a colorless oily liquid, which was the dechlorination product, with an isolation yield of 95%. 1 H NMR (400MHz, CDCl3): δ7.88–7.81(m,4H),7.52–7.48(m,2H),7.45–7.41(m,4H),4.33–4.27(m, 1H), 3.94–3.88 (m, 1H), 3.28–3.24 (m, 1H), 2.77 (t, J = 4.4Hz, 1H), 2.61 (dd, J = 4.9, 2.6Hz, 1H).

[0046] Example 2

[0047] This embodiment provides a method for preparing 1-chloro-3-hydroxypropane-2-diphenylphosphinate, which is as follows:

[0048] Under air, add 0.5 mmol of diphenylphosphoric acid and 2 mL of epichlorohydrin to the reactor, seal the tube, heat to 40°C, and continue stirring at 300 r / min for 10 hours. Stop the reaction, cool to room temperature, evaporate the solvent at room temperature or recrystallize using n-hexane to obtain a white solid as the epoxy ring-opening product with an isolation yield of 95%. 1 H NMR (400MHz, CDCl3): δ7.84–7.79(m,4H),7.56–7.47(m,6H),4.88(d,J=6.3Hz,1H),4.28–4.15(m,2H),4.09–4.03(m,1H),3.64(d,J=6.0Hz,2H).

[0049] Example 3

[0050] This embodiment provides a method for preparing (2-methyloxirane)methyldiphenylphosphinate, which is as follows:

[0051] Under air, 0.5 mmol of diphenylphosphoric acid and 2.5 mL of methyl epichlorohydrin were added to the reactor. After sealing the tube, the mixture was heated to 140°C and stirred at 540 r / min for 12 h. The reaction was stopped and cooled to room temperature. The solvent was removed by distillation under reduced pressure. The crude product was separated by column chromatography to obtain a colorless oily liquid as the dechlorination product with an isolation yield of 74%. 1 H NMR (400MHz, CDCl3): δ7.86–7.79(m,4H),7.54–7.46(m,6H),4.12–3.91(m,2H),2.79–2.66(m,2H),1.44(s,3H).

[0052] Example 4

[0053] This embodiment provides a method for preparing 1-chloro-3-hydroxy-2-methylpropane-2-yl diphenylphosphinate, which is as follows:

[0054] Under air, 0.5 mmol of diphenylphosphoric acid and 2.5 mL of methyl epichlorohydrin were added to the reactor. After sealing the tube, the mixture was heated to 140°C and stirred continuously at 400 r / min for 4 h. The reaction was stopped and cooled to room temperature. The solvent was evaporated at room temperature to obtain a white solid, which was the epoxy ring-opening product, with an isolated yield of 85%. 1 H NMR (400MHz, CDCl3): δ7.85–7.80(m,4H),7.56–7.46(m,6H),4.53(br,1H), 4.12(t,J=11.6Hz,1H),3.99–3.94(m,1H),3.69–3.50(m,2H),1.30(s,3H).

[0055] Example 5

[0056] This embodiment provides a method for preparing [3-chloro-2-(chloromethyl)-2-(hydroxymethyl)propyl]diphenylphosphinate, which is as follows:

[0057] Under air, 0.1 mmol of diphenylphosphoric acid and 0.5 mL of 3,3-bis(chloromethyl)oxetane were added to the reactor. After sealing the tube, the mixture was heated to 120°C and stirred continuously at 300 r / min for 12 h. The reaction was stopped and the mixture was cooled to room temperature. The solvent was evaporated at room temperature to obtain a white solid, which was the four-membered ring-opening product, with an isolated yield of 81%. 1 H NMR (400MHz, CDCl3): δ7.84–7.78(m,4H), 7.59–7.55(m,6H), 4.64(t,J=6.8Hz,1H), 4.03(d,J=9.6Hz,1H), 3.68–3.60(m,6H).

[0058] Example 6

[0059] This embodiment provides a method for preparing 2-oxiranylmethylbis(2,4,4-trimethylpentyl)phosphinate, which is as follows:

[0060] Under air, 0.5 mL of Cyanex272 and 2.0 mL of epichlorohydrin were added to the reactor. After sealing the tube, the mixture was heated to 145° C. and stirred at 540 r / min for 18 h. The reaction was stopped, cooled to room temperature, and the solvent was removed by distillation under reduced pressure. The crude product was separated by column chromatography to obtain an oily liquid, which was the dechlorinated product 2-oxiranylmethylbis(2,4,4-trimethylpentyl)phosphinate, with an isolation yield of 70%. 1 H NMR (400MHz, CDCl3): δ4.31–4.24(m,1H),3.92–3.81(m,1H),3.22–3.20(m,1H),2.84(t,J=4.4Hz,1H),2.67–2.64(m,1H),2.06–1. 99(m,2H),1.85–1.72(m,2H),1.67–1.56(m,2H),1.41–1.34(m,2H),1.22–1.17(m,2H),1.13–1.11(m,6H),1.63(d,J=2.0Hz,18H).

[0061] Example 7

[0062] This embodiment provides a method for preparing 1-chloro-3-hydroxypropane-2-bis(2,4,4-trimethylpentyl)phosphinate, which is as follows:

[0063] Under air, 0.5 mL of Cyanex272 and 0.5 mL of epichlorohydrin were added to the reactor. After sealing the tube, the mixture was heated to 120°C and stirred at 400 r / min for 2 h. The reaction was stopped and cooled to room temperature. The solvent was evaporated at room temperature to obtain an oily crude product. The ring-opening product 1-chloro-3-hydroxypropane-2-bis(2,4,4-trimethylpentyl)phosphinate was obtained by simple separation with an isolation yield of 86%. 1 H NMR (400MHz, CDCl3): δ5.01–4.98(m,1H),4.23–4.14(m,2H),3.97(s,1H),3.61–3.58(m,2H) ,2.07–1.98(m,2H),1.88–1.59(m,4H),1.38–1.33(m,2H),1.26–1.18(m,2H),0.93(s,18H).

[0064] Example 8

[0065] This embodiment provides a method for preparing 2-hydroxycyclohexyl diphenyl phosphinate, which is as follows:

[0066] Under air, 2 mmol of diphenylphosphoric acid and 2.5 mL of cyclohexene oxide were added to the reactor. After sealing the tube, the mixture was heated to 30°C and stirred at 400 r / min for 2 h. The reaction was stopped and cooled to room temperature. The solvent was evaporated at room temperature to obtain a white solid, which was the ring-opening product 2-hydroxycyclohexyl diphenyl phosphinate, with an isolated yield of 99% (phosphoric acid and cyclohexene oxide can only undergo ring-opening reaction, which can achieve nearly 100% conversion). 1 H NMR (400MHz, CDCl3): δ7.86–7.80(m,4H),7.54–7.44(m,6H),5.01(s,1H),3.94–3.87 (m,1H),3.66–3.60(m,1H),2.09–2.00(m,2H),1.70–1.55(m,3H),1.34–1.07(m,3H).

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a hydroxyl- or epoxy-containing organic phosphate from an epoxy compound, characterized in that: The following steps are involved: Under air, a P(O)-OH compound and an epoxy compound are mixed, stirred for reaction, cooled, and purified to obtain a hydroxyl- or epoxy-containing organic phosphate as shown in Formula I: ， Said R1 and R2 are both phenyl or 2,4,4-trimethylpentyl; The epoxy compound is epichlorohydrin, and the epoxy compound serves as both a reaction substrate and a reaction solvent; R3 is oxiran-2-ylmethyl or 1-chloro-3-hydroxypropane-2-yl; The P(O)-OH compound is one of diphenylphosphoric acid and bis(2,4,4-trimethylpentyl)phosphonic acid.

2. A method for preparing a hydroxyl- or epoxy-containing organic phosphate from an epoxy compound, characterized in that: The following steps are involved: Under air, a P(O)-OH compound and an epoxy compound are mixed, stirred for reaction, cooled, and purified to obtain a hydroxyl- or epoxy-containing organic phosphate as shown in Formula I: ， Said R1 and R2 are both phenyl; The epoxy compound is methyl epichlorohydrin, and the epoxy compound serves as both a reaction substrate and a reaction solvent; R3 is (2-methyloxirane-2-yl)methyl or 1-chloro-3-hydroxy-2-methylpropane-2-yl; The P(O)-OH compound is diphenylphosphoric acid.

3. The method for preparing an organic phosphate containing a hydroxyl group or an epoxy group from an epoxy compound according to any one of claims 1 or 2, characterized in that: The mixing molar ratio of the P(O)-OH compound to the epoxy compound is 1:5-60.

4. The method for preparing an organic phosphate containing a hydroxyl group or an epoxy group from an epoxy compound according to any one of claims 1 or 2, characterized in that: The stirring reaction conditions are: at room temperature to 160° C., a stirring speed of 300-600 r / min, and a reaction time of 2-24 h.

5. The method for preparing an organic phosphate containing a hydroxyl group or an epoxy group from an epoxy compound according to claim 4, wherein: When the stirring speed is 300-400 r / min, the reaction temperature is 40-140° C., and the reaction time is 2-12 h, the yield of the epoxy ring-opening product in the reaction product is greater than 80%.

6. The method for preparing an organic phosphate containing a hydroxyl group or an epoxy group from an epoxy compound according to claim 4, wherein: When the stirring speed is 400-600 r / min, the reaction temperature is 120-160° C., and the reaction time is 12-24 h, the yield of the dechlorination product in the reaction product is greater than 70%.

7. The method for preparing an organic phosphate containing a hydroxyl group or an epoxy group from an epoxy compound according to any one of claims 1 or 2, characterized in that: The purification process is as follows: the reaction solution is concentrated by vacuum distillation to obtain a crude product, and the crude product is separated by column chromatography to obtain a dechlorinated product; or the reaction solution is volatilized at room temperature or recrystallized using n-hexane or dichloromethane to obtain a ring-opened product.

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