Disubstituted phosphite and 2-(oxazolidin-3-yl)ethanol derivatives, processes for their preparation and uses thereof

Abstract

The application discloses a kind of di-substituted phosphite and 2-(oxazolidine-3-yl)ethanol derivatives, and preparation method and application thereof.The core step of the method involves mixing catalyst with 2-(oxazolidine-3-yl)ethanol, then gradually adding phosphite compound within the reaction temperature range of 65-70℃, after dropwise addition is completed, the system is reacted at 65-70℃ for 1-10 hours, by adding appropriate amount of propylene oxide to neutralize the acid produced in the reaction until the acid value is reduced to below 5mgKOH / g, so as to ensure the chemical stability of the product;The reaction mixture is distilled under reduced pressure to remove unreacted raw materials and low-boiling impurities, and further purified by fine filtration to obtain high-quality di-substituted phosphite and 2-(oxazolidine-3-yl)ethanol derivative flame retardant.The preparation method of the application not only has simple and clear process design, simple and fast operation process, but also has mild reaction condition, can be efficiently completed without extreme condition, and the catalyst used can be repeatedly used.

Description

Technical Field

[0001] This invention belongs to the field of flame retardant preparation technology, specifically relating to a disubstituted phosphite 2-(oxazolidine-3-yl)ethanol derivative, its preparation method, and its application. Background Technology

[0002] Oxazolidine is a five-membered nitrogen oxide heterocyclic compound and a key organic framework in the field of materials modification. Among its components, 2-(oxazolidine-3-yl)ethanol, as a crucial organic precursor, exhibits numerous superior properties in chemical reactions with other organic substances. These properties are reflected in its ability to promote the synthesis of cashew nut shell Mannich polyols and to drive innovative research and development in cashew nut shell Mannich polyols and rigid polyurethane foams. Furthermore, organophosphates are indispensable basic compounds in the materials field, especially phosphites, which are often used as flame retardants due to their excellent environmental friendliness. However, in the past, the preparation of flame retardants involved reacting 2-(oxazolidine-3-yl)ethanol with phosphites. This process often required the use of strong bases to reduce the by-product acids produced in the reaction. For example, Chinese patent CN 102276645A uses sodium hydroxide, where sodium ions are difficult to remove, and residual sodium ions are detrimental to polyurethane foaming. Chinese patent CN 111004364A uses calcium hydroxide. These strong bases not only impact the environment but also increase post-processing costs. Given these shortcomings, developing a novel strategy is particularly urgent. Furthermore, preliminary research indicates that the reaction structures of 2-(oxazolidine-3-yl)ethanol with certain phosphites have not yet been reported. Summary of the Invention

[0003] To address the above-mentioned problems, the present invention aims to provide a disubstituted phosphite 2-(oxazolidine-3-yl)ethanol derivative, its preparation method, and its application.

[0004] The technical solution adopted in this invention is as follows:

[0005] A disubstituted phosphite-2-(oxazolidine-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-(oxazolidine-3-yl)ethanol derivative includes the following steps:

[0009] Step 1: At 40-110℃ and with the action of a catalyst, add dropwise a phosphite compound as shown in formula (2) and an excess of 2-(oxazolidine-3-yl)ethanol as shown in formula (3). Keep the reaction at this temperature for 1-10 h to obtain a disubstituted phosphite 2-(oxazolidine-3-yl)ethanol derivative and a small amount of acidic byproducts.

[0010] Step 2: After the reaction is complete, adjust the acid value to below 5 mg KOH / g with an appropriate amount of propylene oxide to obtain the crude product of the disubstituted phosphite-2-(oxazolidine-3-yl)ethanol derivative;

[0011] Step 3: The crude product obtained in Step 2 is sequentially subjected to vacuum de-epoxypropylene and reduced pressure filtration catalyst to obtain the target product, disubstituted phosphite-2-(oxazolidine-3-yl)ethanol derivative. The finished product has an acid value of <5 mgKOH / g and a viscosity of 100-14000 mPa·S / 25℃.

[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 feed amount is 0.05%-1.1% of the mass of (oxazolidine-3-yl)ethanol, preferably 0.7%-1.1%.

[0016] Further, in step 1, the molar ratio of the phosphite compound as shown in formula (2) to 2-(oxazolidine-3-yl)ethanol is 1:1-5, preferably 1:1.01-1.3.

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

[0018] Preferably, the heat preservation time after adding 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 compounds.

[0020] Furthermore, in step 3, the heating temperature is lowered so that the temperature inside the system is between 25-35°C, and the crude product is removed from excess propylene oxide under vacuum conditions.

[0021] Application of a disubstituted phosphite-2-(oxazolidine-3-yl)ethanol derivative in the preparation of combustion improvers.

[0022] By employing the defined techniques, the beneficial effects of the present invention compared to existing technologies are as follows:

[0023] 1) This method not only has a simple and clear process design and a simple and quick operation process, but also has mild reaction conditions, 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. This 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. Attached Figure Description

[0025] Figure 1 This is the phosphorus NMR spectrum after the reaction in Example 1 of the present invention;

[0026] Figure 2 The hydrogen spectrum of the product of Example 1 of this invention;

[0027] Figure 3 This is the phosphorus NMR spectrum after the reaction in Example 2 of the present invention;

[0028] Figure 4 This is the hydrogen spectrum of the product from Example 2 of the present invention. Detailed Implementation

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

[0030] Testing instrument: Nuclear magnetic resonance (NMR);

[0031] Example 1:

[0032] 1) In a 2L four-necked flask, add 678.23g of 95% pure 2-(oxazolidine-3-yl)ethanol and 6.78g of resin catalyst. When the mixture is stirred and heated to 65℃, start adding 1361.76g of 92.56% pure bis-(2-chloroisopropyl)-2-chloroisopropyl phosphate. After the addition is complete, keep the mixture at 65℃ for 4 hours. Take a sample and test the content of phosphite compounds, which is less than 5%.

[0033] 2) Take samples to test the acid value, calculate the amount of propylene oxide to be added. After adding 1% of the total feed mass of propylene oxide at 65℃ and stirring for 1 hour, the acid value of the system should be less than 5 mg KOH / g.

[0034] 3) After the reaction is complete, reduce the heating temperature to 25°C. Remove excess propylene oxide from the crude product under vacuum (0.099 MPa). Since propylene oxide has a low boiling point, vacuuming for 3 hours at 25°C is sufficient. Then, remove the resin catalyst by vacuum filtration to obtain bis-(2-chloroisopropyl)-2-chloroisopropyl-2-(oxazolidine-3-yl)ethyl phosphate (acid value 3 mg KOH / g; viscosity 361.1 mPa·S / 25°C).

[0035] Figure 1 This is the characterization result of the product in step 1 of Example 1 of the present invention. During the synthesis reaction stage, characterization and localization determined that the position of the raw material bis-(2-chloroisopropyl)-2-chloroisopropylphosphonate in NMR was 10-4 ppm, and the position of bis-(2-chloroisopropyl)-2-chloroisopropyl-2-(oxazolidine-3-yl)ethylene glycol phosphate was 28-24 ppm. Figure 1 The results showed that the esterification stage was complete, with a low diester content. Figure 2 The image shows the hydrogen NMR spectrum of the finished product, in which... 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] Example 2:

[0037] 1) In a 2L four-necked flask, add 569.71g of 95% pure 2-(oxazolidine-3-yl)ethanol and 5.69g of resin-type catalyst. When the mixture is stirred and heated to 70℃, start adding 1623.67g of 95% pure bis[2-chloro-1-(chloromethyl)ethyl]-2,3-dichloropropyl phosphate. After the addition is complete, keep the mixture at 70℃ for 4 hours. Take a sample and test the content of phosphite compounds, which is less than 5%.

[0038] 2) Take samples to test the acid value, calculate the amount of propylene oxide to be added. After adding 1% of the total feed mass of propylene oxide at 70℃ and stirring for 1 hour, the acid value of the system should be less than 5 mg KOH / g.

[0039] 3) After the reaction is complete, reduce the heating temperature to 25°C. Remove excess propylene oxide from the crude product under vacuum (0.099 MPa). Since propylene oxide has a low boiling point, vacuuming for 4 hours at 25°C is sufficient. Then, remove the resin catalyst by vacuum filtration to obtain bis[2-chloro-1-(chloromethyl)ethyl]-2,3-dichloropropyl-2-(oxazolidine-3-yl)ethylene glycol phosphate (acid value 4.2 mg KOH / g; viscosity 7000 mPa·S / 25°C).

[0040] Figure 3 This is the characterization result of the product in step 1 of Example 2 of the present invention. During the synthesis reaction stage, the NMR spectroscopy determined that the position of the starting material bis[2-chloro-1-(chloromethyl)ethyl]-2,3-dichloropropyl phosphate was 10-4 ppm, and the positions of bis[2-chloro-1-(chloromethyl)ethyl]-2,3-dichloropropyl-2-(oxazolidine-3-yl)ethylene glycol phosphate were 28 ppm and 18 ppm, respectively. Figure 3 The results showed that the esterification stage was complete, with a low diester content. Figure 4 This is the hydrogen NMR spectrum of the finished product. 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 was designated as flame retardant A, and the product obtained in Example 2 was designated as flame retardant B. A control group was used without added flame retardants. Following the foaming formulation shown in Table 1, 20 grams of the products from Examples 1 and 2 were added as flame retardants and mixed thoroughly. The stirring speed was adjusted to 2100 rpm and timed for 1 minute. After the time was complete, a disposable paper cup was first soaked in MDI (diphenylmethane diisocyanate), then placed in an analytical balance, tare, and weighed to obtain 159 grams of material. This material was placed next to the stirrer. The cup was held in the right hand and placed under the stirrer, while the stirring speed was controlled with the left hand. The speed was increased to 1800 rpm for approximately 15 seconds, then reduced to 700 rpm. The MDI from the paper cup was quickly poured into a plastic bucket, and the stirring speed was increased to 2800 rpm for approximately 8 seconds. The stirrer power was then immediately turned off. Pour the stirred liquid from the plastic bucket into a pre-prepared square mold (side: approximately 200mm * height: approximately 200mm), and wait for it to set. Remove the set foam from the mold, tear off the newspaper on the side, and write a number on it. Prepare samples according to standard GB / T2406.2-2009 and determine their flame retardant properties, such as limiting oxygen index and vertical burning test. The limiting oxygen index should be determined.

[0043] Table 1 summarizes the results of application tests on flame retardants.

[0044]

[0045]

[0046] According to the data in the table, comparing the product of the comparative example with the control group, the results showed that its limiting oxygen index was significantly higher than that of the blank group, indicating that the two newly synthesized flame retardants have significant flame retardant effects.

Claims

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

2. A process for the preparation of a disubstituted phosphite and 2-(oxazolidin-3-yl)ethanol derivative according to claim 1, characterized in that, The method comprises the following steps: Step 1: drop the phosphite compound shown as formula (2) and excessive 2-(oxazolidin-3-yl)ethanol shown as formula (3) at 40-110 DEG C and under the action of a catalyst, and keep the reaction for 1-10 hours to obtain a disubstituted phosphite and 2-(oxazolidin-3-yl)ethanol derivative and a small amount of acidic by-product; Step 2: after the reaction, adjust the acid value to less than 5 mgKOH / g by using proper propylene oxide to obtain the crude product of the 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 in sequence to obtain the target product of the disubstituted phosphite and 2-(oxazolidin-3-yl)ethanol derivative, and the finished product has an acid value of less than 5 mgKOH / g and a viscosity of 100-14000 mPa s / 25 DEG C; The reaction formula is as follows: ， In the formula, the substituent group R is -CH(CH3)CH2Cl or -CH(CH2Cl)CH2Cl; The catalyst in step 1 is a resin catalyst, and the feeding amount is 0.05%-1.1% of the mass of 2-(oxazolidin-3-yl)ethanol.

3. A process for the preparation of a disubstituted phosphite and 2-(oxazolidin-3-yl)ethanol derivative according to claim 2, characterized in that, The feeding amount of the catalyst in step 1 is 0.7-1.1% of the mass of 2-(oxazolidin-3-yl)ethanol.

4. The process for preparing a disubstituted phosphite and 2-(oxazolidin-3-yl)ethanol derivative according to claim 2, characterized in that, The feeding molar ratio of the phosphite compound shown as formula (2) to 2-(oxazolidin-3-yl)ethanol in step 1 is 1:1-5.

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

3.

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

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

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

9. A process for the preparation of a disubstituted phosphite and 2-(oxazolidin-3-yl)ethanol derivative according to claim 2, characterized by, In step 3, the heating temperature is reduced so that the temperature in the system is 25-35 DEG C, and the excess propylene oxide is removed from the crude product under vacuum.

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

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