Disubstituted phosphite ester and 2-(oxazolidine-3-yl) ethanol derivative as well as preparation method and application thereof

Abstract

The invention discloses a disubstituted phosphite ester and 2-(oxazolidine-3-yl) ethanol derivative as well as a preparation method and application of the disubstituted phosphite ester and 2-(oxazolidine-3-yl) ethanol derivative. The method comprises the following core steps: mixing a catalyst with 2-(oxazolidine-3-yl) ethanol, gradually dropwise adding a phosphite ester compound within a reaction temperature range of 65-70 DEG C, reacting the system at 65-70 DEG C for 1-10 hours after dropwise adding, and adding a proper amount of epoxypropane to neutralize the acid generated in the reaction until the acid value is reduced to below 5mgKOH / g, thereby obtaining the 2-(oxazolidine-3-yl) ethanol. The chemical stability of the product is ensured; and carrying out reduced pressure distillation on the reaction mixture to remove unreacted raw materials and low-boiling-point impurities, and carrying out fine filtration for further purification to obtain the high-quality disubstituted phosphite ester and 2-(oxazolidine-3-yl) ethanol derivative flame retardant. The preparation method disclosed by the invention is simple and clear in process design, simple, convenient and rapid in operation process, mild in reaction condition and capable of being efficiently completed without extreme conditions, and the used catalyst can be repeatedly used.

Description

Technical Field

[0001] The invention belongs to the technical field of flame retardant preparation, and specifically relates to a disubstituted phosphite 2-(oxazolidin-3-yl)ethanol derivative and a preparation method and application thereof. Background Art

[0002] Oxazolidine is a five-membered nitrogen oxide heterocyclic compound, a key organic skeleton in the field of material modification. Among them, 2- (oxazolidine-3-yl) ethanol, as a class of crucial organic precursors, exhibits many excellent properties in chemical reactions with other organic substances, which are reflected in aspects such as promoting the synthesis of cardanol Mannich polyols, and promoting the innovative research and development of cashew Mannich polyols and polyurethane rigid foams. In addition, organophosphates are indispensable basic compounds in the field of materials, especially phosphites, which are often used as flame retardants by virtue of their outstanding environmentally friendly properties. However, in the past, when preparing flame retardants, 2- (oxazolidine-3-yl) ethanol was used to react with phosphites, and this process often required the use of a strong base to reduce the by-product acid produced by the reaction, such as sodium hydroxide used in Chinese patent CN 102276645A, in which sodium ions are not easily disposed of, and residual sodium ions are not conducive to polyurethane foaming, and Chinese patent CN 111004364A uses calcium hydroxide, and these strong bases not only have an impact on the environment, but also increase post-processing costs. In view of these shortcomings, it is particularly urgent to develop a new strategy. In addition, after preliminary research, it was noted that the reaction structure of 2-(oxazolidin-3-yl)ethanol and some phosphites has not been reported. Summary of the invention

[0003] In view of the above problems, the object of the present invention is to provide a disubstituted phosphite 2-(oxazolidin-3-yl)ethanol derivative and a preparation method and application thereof.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A disubstituted phosphite 2-(oxazolidin-3-yl)ethanol derivative, the structural formula of which is shown in formula (1):

[0006]

[0007] In the formula, the substituent R is -CH(CH3)CH2Cl or -CH(CH2Cl)CH2Cl.

[0008] A method for preparing a disubstituted phosphite 2-(oxazolidin-3-yl)ethanol derivative comprises the following steps:

[0009] Step 1: at 40-110° C. and in the presence of a catalyst, dropwise add a phosphite compound represented by formula (2) and an excess of 2-(oxazolidin-3-yl)ethanol represented by formula (3) to react, and keep the reaction warm for 1-10 hours to obtain a disubstituted phosphite and 2-(oxazolidin-3-yl)ethanol derivative and a small amount of acidic byproducts;

[0010] Step 2: After the reaction is completed, an appropriate amount of propylene oxide is used to adjust the acid value to below 5 mgKOH / g to obtain a crude disubstituted phosphite and 2-(oxazolidin-3-yl)ethanol derivative;

[0011] Step 3: The crude product obtained in step 2 is subjected to vacuum propylene oxide removal and reduced pressure filtration of the catalyst to obtain the target product, a disubstituted phosphite and 2-(oxazolidin-3-yl)ethanol derivative, wherein the acid value of the finished product is less than 5 mgKOH / g and the viscosity is 100-14000 mPa·S / 25°C;

[0012] The reaction formula is as follows:

[0013]

[0014] In the formula, the substituent R is -CH(CH3)CH2Cl or -CH(CH2Cl)CH2Cl.

[0015] Furthermore, the catalyst in step 1 is a resin-type catalyst, and the dosage is 0.05%-1.1% of the mass of -(oxazolidin-3-yl)ethanol, preferably 0.7-1.1%.

[0016] Furthermore, in step 1, the molar ratio of the phosphite compound represented by formula (2) to 2-(oxazolidin-3-yl)ethanol is 1:1-5, preferably 1:1.01-1.3.

[0017] Preferably, the reaction temperature in step 1 is 65-70°C.

[0018] Preferably, the holding time after the dropwise addition of the phosphite compound is 2-6 hours.

[0019] Furthermore, in step 2, the amount of propylene oxide used is 1%-10% of the total mass of the phosphite compound.

[0020] Furthermore, in step 3, the heating temperature is lowered so that the temperature in the system is between 25° C. and 35° C., and the crude product is subjected to vacuum conditions to remove excess propylene oxide.

[0021] The invention discloses an application of a disubstituted phosphite 2-(oxazolidin-3-yl)ethanol derivative in the preparation of a combustion improver.

[0022] By adopting the defined technology, compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1) This method not only has a concise and clear process design and a simple and fast operation process, but also has mild reaction conditions and can be completed efficiently without extreme conditions, and the catalyst used can be reused.

[0024] 2) The preparation scheme has mild reaction conditions and can be completed efficiently without extreme conditions. It is also compatible with existing chemical production equipment, providing a solid foundation for large-scale industrial production. The present invention not only provides a new structural type for the preparation of phosphorus-containing combustion aids, but also provides a more efficient and green preparation method. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the nuclear magnetic resonance phosphorus spectrum after the reaction of Example 1 of the present invention;

[0026] Figure 2 is the hydrogen spectrum of the product of Example 1 of the present invention;

[0027] Figure 3 This is the nuclear magnetic resonance phosphorus spectrum after the reaction of Example 2 of the present invention;

[0028] Figure 4 This is the hydrogen spectrum of the product of Example 2 of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with specific embodiments and the accompanying drawings, but the protection scope of the present invention is not limited thereto.

[0030] Testing instrument: NMR;

[0031] Embodiment 1:

[0032] 1) In a 2L four-necked flask, add 678.23g of 95% pure 2-(oxazolidin-3-yl)ethanol and 6.78g of a resin-type catalyst, stir and heat to 65°C, then start to dropwise add 1361.76g of 92.56% pure bis-(2-chloroisopropyl)-2-chloroisopropyl phosphate, after the addition is complete, keep warm at 65°C for 4h, take samples and detect the content of phosphite compounds to be less than 5%.

[0033] 2) Take samples to test the acid value, calculate the amount of propylene oxide added, and add propylene oxide (1% by weight of the total feed) dropwise at 65° C. and stir for 1 hour. The acid value of the test system is less than 5 mgKOH / g.

[0034] 3) After the reaction is completed, the heating temperature is lowered to make the temperature in the system below 25°C, and the crude product is subjected to vacuum conditions (vacuum degree is 0.099MPa) to remove excess propylene oxide. Since propylene oxide has a low boiling point, vacuum can be applied at 25°C for 3 hours. The resin-type catalyst is then removed by reduced pressure filtration to obtain bis-(2-chloroisopropyl)-2-chloroisopropyl and 2-(oxazolidin-3-yl)ethyl phosphate (acid value 3mgKOH / g; viscosity 361.1mPa·S / 25°C).

[0035] Figure 1 It is the characterization result of the product of step 1 in Example 1 of the present invention. In the synthesis reaction stage, the position of the raw material bis-(2-chloroisopropyl)-2-chloroisopropylphosphonate in nuclear magnetic resonance is determined to be 10-4ppm, and the position of bis-(2-chloroisopropyl)-2-chloroisopropyl and 2-(oxazolidin-3-yl) ethylene glycol phosphate is 28-24ppm. Figure 1 The results showed that the esterification stage had been completed and the diester content was low. Figure 2 is the finished product NMR hydrogen spectrum, where 1 H NMR(400MHz,Chloroform-d)δ4.67(ddd,J=25.2,9.9,5.9Hz,2H),4.03(dtd,J=28.7,17.0,14.0,8.3Hz,4H ), 3.54(dd,J=10.1,4.3Hz,6H), 3.02(dtd,J=19.7,9.6,4.1Hz,2H), 2.78-2.63(m,4H), 1.43-1.32(m,6H).

[0036] Embodiment 2:

[0037] 1) In a 2L four-necked flask, add 569.71g of 95% pure 2-(oxazolidin-3-yl)ethanol and 5.69g of a resin-type catalyst, stir and heat to 70°C, then start to dropwise add 1623.67g of 95% pure bis[2-chloro-1-(chloromethyl)ethyl]-2,3-dichloropropyl phosphate, after the dropwise addition is complete, keep warm at 70°C for 4h, take samples and detect the phosphite compound content to be less than 5%.

[0038] 2) Take samples to test the acid value, calculate the amount of propylene oxide added, and add propylene oxide (1% by weight of the total feed) dropwise at 70° C. and stir for 1 hour. The acid value of the test system is less than 5 mgKOH / g.

[0039] 3) After the reaction is completed, the heating temperature is lowered so that the temperature in the system is below 25°C, and the crude product is subjected to vacuum conditions (vacuum degree is 0.099 MPa) to remove excess propylene oxide. Since propylene oxide has a low boiling point, vacuuming is performed for 4 hours at 25°C. The resin-type catalyst is then removed by reduced pressure filtration to obtain bis[2-chloro-1-(chloromethyl)ethyl]-2,3-dichloropropyl-2-(oxazolidin-3-yl)ethylene glycol phosphate (acid value 4.2 mgKOH / g; viscosity 7000 mPa·S / 25°C).

[0040] Figure 3 It is the characterization result of the product of step 1 in Example 2 of the present invention. In the synthesis reaction stage, the position of the raw material bis[2-chloro-1-(chloromethyl)ethyl]-2,3-dichloropropyl phosphate in nuclear magnetic resonance is determined to be 10-4ppm, and the position of bis[2-chloro-1-(chloromethyl)ethyl]-2,3-dichloropropyl and 2-(oxazolidin-3-yl)ethylene glycol phosphate is 28ppm and 18ppm. Figure 3 The results showed that the esterification stage had been completed and the diester content was low. Figure 4 This is the finished product NMR hydrogen spectrum. 1 H-NMR(400MHz,Chloroform-d)δ4.82(dp,J=13.6,5.1Hz,2H),4.36-4.23(m,2H),4.05-3 .98(m,2H),3.78(dd,J=7.1,3.8Hz,4H),3.63(dd,J=14.5,5.1Hz,8H),2.80-2.70(m,4H).

[0041] Application Examples

[0042] The product obtained in Example 1 is recorded as flame retardant A, and the product obtained in Example 2 is recorded as flame retardant B. No flame retardant is added as a control group. According to the foaming formula shown in Table 1, according to the weight formula, 20 grams of the products in Examples 1 and 2 are added as flame retardants, and mixed and stirred evenly. The speed is adjusted to 2100 rpm, and the timing is 1 minute. After the end, the disposable paper cup is first soaked with MDI (diphenylmethane diisocyanate), then placed in an analytical balance, peeled, 159 grams of material is weighed, and placed next to the agitator. Hold it with the right hand and put it under the agitator, control the speed with the left hand, increase it to 1800 rpm, about 15 seconds, reduce the speed to 700 rpm, quickly pour the TDI in the paper cup into a plastic bucket, increase the speed to 2800 rpm, about 8 seconds, and then directly turn off the agitator power. Pour the stirred liquid in the plastic bucket into the prepared square mold (side: about 200mm*height: about 200mm), wait for molding, take the molded foam out of the mold, tear off the newspaper on the side, and write the number. According to the standard GB / T2406.2-2009, prepare the sample and measure its flame retardant properties such as limiting oxygen index and vertical burning test, and measure the limiting oxygen index.

[0043] Table 1 Summary of the results of flame retardant application tests

[0044]

[0045]

[0046] According to the data in the table, the example products were compared with the control group, and the results showed that the limiting oxygen index was significantly higher than that of the blank group, which indicated that the two newly synthesized flame retardants had significant flame retardant effects.

Claims

1. A disubstituted phosphite 2-(oxazolidin-3-yl)ethanol derivative, characterized in that: Its structural formula is shown in formula (1): In the formula, the substituent R is -CH(CH3)CH2Cl or -CH(CH2Cl)CH2Cl.

2. A method for preparing a disubstituted phosphite 2-(oxazolidin-3-yl)ethanol derivative as claimed in claim 1, characterized in that: The steps include: Step 1: at 40-110° C. and in the presence of a catalyst, dropwise add a phosphite compound represented by formula (2) and an excess of 2-(oxazolidin-3-yl)ethanol represented by formula (3) to react, and keep the reaction warm for 1-10 hours to obtain a disubstituted phosphite and 2-(oxazolidin-3-yl)ethanol derivative and a small amount of acidic byproducts; Step 2: After the reaction is completed, an appropriate amount of propylene oxide is used to adjust the acid value to below 5 mgKOH / g to obtain a crude disubstituted phosphite and 2-(oxazolidin-3-yl)ethanol derivative; Step 3: The crude product obtained in step 2 is subjected to vacuum propylene oxide removal and reduced pressure filtration of the catalyst to obtain the target product, a disubstituted phosphite and 2-(oxazolidin-3-yl)ethanol derivative, wherein the acid value of the finished product is less than 5 mgKOH / g and the viscosity is 100-14000 mPa·S / 25°C; The reaction formula is as follows: In the formula, the substituent R is -CH(CH3)CH2Cl or -CH(CH2Cl)CH2Cl.

3. The method for preparing a disubstituted phosphite 2-(oxazolidin-3-yl)ethanol derivative according to claim 2, characterized in that: The catalyst in step 1 is a resin-type catalyst, and the feed amount is 0.05%-1.1% of the mass of -(oxazolidin-3-yl)ethanol, preferably 0.7-1.1%.

4. The method for preparing a disubstituted phosphite 2-(oxazolidin-3-yl)ethanol derivative according to claim 2, characterized in that: The molar ratio of the phosphite compound represented by formula (2) to 2-(oxazolidin-3-yl)ethanol in step 1 is 1:1-5, preferably 1:1.01-1.

3.

5. The method for preparing a disubstituted phosphite 2-(oxazolidin-3-yl)ethanol derivative according to claim 2, characterized in that: The reaction temperature in step 1 is 65-70°C.

6. The method for preparing a disubstituted phosphite 2-(oxazolidin-3-yl)ethanol derivative according to claim 2, characterized in that: The heat preservation time after the addition of the phosphite compound is 2-6 hours.

7. The method for preparing a disubstituted phosphite 2-(oxazolidin-3-yl)ethanol derivative according to claim 2, characterized in that: In step 2, the amount of propylene oxide used is 1%-10% of the total mass of the phosphite compound.

8. The method for preparing a disubstituted phosphite 2-(oxazolidin-3-yl)ethanol derivative according to claim 2, characterized in that: In step 3, the heating temperature is lowered so that the temperature in the system is between 25° C. and 35° C., and the crude product is subjected to vacuum conditions to remove excess propylene oxide.

9. Use of the disubstituted phosphite 2-(oxazolidin-3-yl)ethanol derivative as claimed in claim 1 in the preparation of a combustion improver.

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