Polyphosphoric acid supported ionic liquid fiber catalyst, preparation method and application of the catalyst in catalytic synthesis of tcpp flame retardant

Abstract

The application relates to a PPS solid-supported ionic liquid fiber catalyst, a preparation method and application of the PPS solid-supported ionic liquid fiber catalyst in catalytic synthesis of TCPP flame retardant, and mainly comprises the following steps: one, preparation of quaternary aminated polyphenylene sulfide fiber (PPS): quaternary ammonium PPS fiber is obtained after reaction of tertiary amine and chloromethylated PPS fiber; two, reaction of the quaternary ammonium PPS fiber and ZnCl2 to obtain a PPS solid-supported ionic liquid catalyst; three, catalytic synthesis of TCPP flame retardant: after reaction of phosphorus trichloride or phosphorus oxychloride and an epoxide compound by using the fiber catalyst, reaction TCPP flame retardant is obtained through vacuum concentration. The application not only can quickly take out the catalyst, recycle the catalyst, save the cost, avoid a complicated catalyst removal process, but also purifies the product through the vacuum concentration method, avoids complicated and environment-pollution-easy steps such as alkali washing and water washing, and has good industrial application value.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of flame retardant synthesis, and relates to a method for catalytically synthesizing a trisphosphazene sulfonate flame retardant through phase transfer PPS. BACKGROUND

[0002] Organophosphate flame retardants have a wide variety of species and have been widely used in consumer products and industrial products such as furniture, textiles, electronic products and building materials. Among them, tris(chloropropyl) phosphate (TCPP) is a commonly used low molecular weight phosphorus halogen flame retardant, mainly used for flame retardation of polyvinyl chloride, polystyrene, phenolic resin, propylene resin, rubber and paint, and has significant flame retardation and certain plasticizing effect.

[0003] CN110294773B discloses a TCPP flame retardant preparation method and a TCPP flame retardant prepared therefrom. The method comprises synthesizing TCPP crude product by reacting phosphorus oxychloride with propylene oxide under the action of a Lewis acid catalyst, adding the prepared TCPP crude product to an acidic aqueous solution for hydrolysis treatment, washing and removing the water layer, and then adding to an inorganic oxidizing agent microcapsule solution for reaction after dehydration by reduced pressure distillation. After standing and separating, the product is washed with alkali, washed with water and distilled. Compared with the prior art, the application can effectively remove the odor of the product without affecting the yield of the TCPP product, and has little effect on the quality of the TCPP product. The prepared TCPP product has good hydrolysis resistance, is suitable for industrial production, and has good application prospect.

[0004] CN102775439B discloses a preparation method of a flame retardant TCPP. A programmed temperature method is used in the reaction process of phosphorus oxychloride and propylene oxide. The product quality yield is more than 93%, and the impurity content of the crude product is less than 3.0%. In the post-treatment process, the crude product is treated with organic peroxide, and the aldehyde in the crude product is oxidized into an acidic substance by the oxidation of the peroxide. Then, the product is prepared by alkali washing, water washing, reduced pressure dehydration and the like in the subsequent treatment process. The application optimizes the process conditions and flow of the reaction, and the acidic product and the remaining peroxide obtained by oxidation have good water solubility, which can be easily removed through the subsequent process, so as to achieve the purpose of effectively removing odor and impurities. In addition, the application can reduce the amount of washing water and the discharge of waste water.

[0005] TCPP is usually prepared by esterification of phosphorus oxychloride with propylene oxide in the presence of Lewis acid catalysts such as aluminum chloride and titanium tetrachloride, followed by a series of post-treatments such as alkali washing, water washing and distillation. The traditional production process has problems such as the catalyst cannot be recycled, the product quality is unstable, and the environmental pollution is serious. Therefore, it is necessary to develop a TCPP flame retardant preparation method which can ensure high product yield, realize catalyst recycling, stable product quality and less environmental pollution. SUMMARY

[0006] In view of the problems in the prior art, the application provides a PPS solid-supported ionic liquid fiber catalyst, a preparation method and application of the catalyst in catalytic synthesis of TCPP flame retardant. The method has the advantages of simple preparation process, high catalytic activity and good cycle performance, thereby solving the problems of non-recyclable small molecule catalysts, environmental pollution and resource waste in the synthesis of TCPP flame retardant.

[0007] To solve the above technical problems, the application adopts the following technical scheme:

[0008] A preparation method of a PPS solid-supported ionic liquid fiber catalyst, comprising the following steps:

[0009] (1) Chloromethylation of PPS fiber: PPS fiber, paraformaldehyde, tin tetrachloride, trimethylchlorosilane and 1,2-dichloroethane are added into an autoclave, and after reaction in an oven for a period of time, the fiber is taken out and cleaned with ethanol, and then dried to obtain chloromethylated PPS fiber PPS-Cl;

[0010] (2) Quaternization of PPS: chloromethylated PPS fiber PPS-Cl and a solution of tertiary amine in acetonitrile are added into an autoclave, and after reaction in an oven for a period of time, the fiber is taken out and cleaned with ethanol, and then dried to obtain quaternized PPS fiber PPS-QA;

[0011] (3) PPS solid-supported ionic liquid: quaternized PPS fiber PPS-QA and a ZnCl2 aqueous solution are added into an autoclave, and after reaction in an oven at a certain temperature for a period of time, the fiber is taken out and cleaned with ethanol, and then dried in a vacuum drying oven to obtain PPS solid-supported ionic liquid fiber PPS-QAZn, i.e. PPS solid-supported ionic liquid fiber catalyst.

[0012] Further, in step (1), the mass ratio of PPS fiber to reaction solution is 1:20-1:80, and the reaction solution is composed of paraformaldehyde, tin tetrachloride, trimethylchlorosilane and 1,2-dichloroethane solution. The mass concentrations of paraformaldehyde, tin tetrachloride and trimethylchlorosilane in the reaction solution are 5-15%, 8-20% and 5-15%, respectively.

[0013] Further, the reaction temperature in the step (1) is 50-100℃, and the reaction time is 24-72h.

[0014] Further, in the step (2), the mass ratio of PPS-Cl fiber to the acetonitrile solution of tertiary amine is 1:10-1:50, and the concentration of the acetonitrile solution of tertiary amine is 3-10mol / L.

[0015] Further, in the step (2), the reaction temperature is 50-100℃, and the reaction time is 12-36h.

[0016] Further, in the step (2), the tertiary amine is one of triethylamine, pyridine and N-methyl imidazole.

[0017] Further, in the step (3), the mass ratio of PPS-QA fiber to the aqueous solution of zinc chloride is 1:20-1:100, and the mass ratio of ZnCl2 to PPS-QA is 1:1-1:3.

[0018] Further, in the step (3), the reaction temperature is 60-150℃, and the reaction time is 2-48h.

[0019] The application further provides a PPS solid-supported ionic liquid fiber catalyst prepared by the preparation method.

[0020] The application further provides application of the PPS solid-supported ionic liquid fiber catalyst in catalytic synthesis of TCPP flame retardant, and the steps are as follows: the fiber catalyst is added into phosphorus oxychloride or phosphorus trichloride and heated and stirred to a certain temperature, then propylene oxide is slowly added into the reaction system, and the reaction temperature is kept increasing, after the addition is completed, the temperature is kept and the reaction is kept for a certain time; after the reaction is completed, the fiber catalyst is taken out, the reaction liquid is concentrated under reduced pressure at the reaction temperature, and then TCPP flame retardant is obtained.

[0021] Further, the molar ratio of propylene oxide to phosphorus oxychloride or phosphorus trichloride is 1:1-5:1, and the dosage of the fiber catalyst is 0.001%-2.0% of the total weight of the reaction raw materials.

[0022] Further, in the step (4), the temperature of phosphorus oxychloride or phosphorus trichloride is controlled to be 30℃-100℃ before the addition of propylene oxide, the final reaction temperature is 50℃-120℃ after the addition of propylene oxide, and the reaction time is 2-12h; in the step (4), the pressure of the reduced pressure concentration is 0.01-0.1mbar at the temperature of the reduced pressure concentration.

[0023] Compared with the prior art, the technical scheme of the application has the beneficial effects that:

[0024] The application is first to prepare a PPS solid-supported ionic liquid and use it in catalytic synthesis of TCPP flame retardant. The catalyst has simple preparation process, excellent catalytic effect, easy separation and good recycling performance. The problems of non-recyclable, environmental pollution and high cost of existing small molecule catalysts are effectively solved. Since the application adopts a solid catalyst, the steps of alkali washing and water washing after reaction in the traditional process can be avoided, the process flow is simplified and the product quality stability is improved. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 PPS fiber solid-supported ionic liquid route schematic diagram.

[0026] Figure 2 Catalytic synthesis of TCPP salt flame retardant example. DETAILED DESCRIPTION

[0027] The application will be further described below in combination with specific examples. It should be understood that the following examples are only used to illustrate the application and not to limit the scope of the application, and those skilled in the art can make some non-essential improvements and adjustments according to the content of the above application. If the specific experimental steps or conditions are not specified in the examples, the operation or conditions can be carried out according to the conventional experimental steps described in the literature in the art. If the reagents or instruments used are not specified by the manufacturer, they are all conventional reagent products that can be obtained by market purchase.

[0028] Example 1

[0029] The method of PPS solid-supported ionic liquid catalytic synthesis of TCPP flame retardant in this example is as follows:

[0030] Step 1: chloromethylation of PPS fiber: 1g of PPS fiber, 3.6g of paraformaldehyde, 5.2g of tin tetrachloride, 4.4g of trimethylchlorosilane and 40mL of 1,2-dichloroethane were added into an autoclave, and the reaction was carried out in a 60℃ oven for 40h. The fiber was taken out and cleaned with ethanol, and then dried to obtain chloromethylated PPS fiber PPS-Cl;

[0031] Step 2: quaternization of PPS: 1g of PPS-Cl fiber, 0.1mol of triethylamine and 20mL of acetonitrile were added into an autoclave, and the reaction was carried out in an 80℃ oven for 24h. The fiber was taken out and cleaned with ethanol, and then dried to obtain quaternized PPS fiber PPS-TQA;

[0032] Step 3: PPS solid-supported ionic liquid: 1g of PPS-TQA fiber, 1g of ZnCl2 and 20mL of n-heptane were added into an autoclave, and the reaction was carried out in an 80℃ oven for 4h. The fiber was taken out and cleaned with n-heptane, and then dried in a 60℃ vacuum drying oven for 12h to obtain PPS solid-supported triethylamine ionic liquid fiber PPS-TQAZn;

[0033] Step 4: Catalytic synthesis of TCPP flame retardant: 30 mg of fiber catalyst PPS-TQAZn was added into 10 mmol (1.37 g) of phosphorus oxychloride, and heated and stirred until the temperature rose to 60 °C. Then 40 mmol (3.7 g) of propylene oxide was slowly added to the reaction system, and the reaction temperature was gradually increased to 80 °C. After the addition was completed, the reaction was continued at 80 °C for 5 h. After the reaction was completed, the fiber catalyst was removed, and the reaction liquid was concentrated at 80 °C and 0.1 mbar until no bubbles were generated, to obtain the TCPP flame retardant. The yield was 95%, and the acid value was less than 0.1 mg KOH / g.

[0034] Example 2

[0035] The method for synthesizing TCPP flame retardant by PPS-supported ionic liquid catalysis in this example is as follows:

[0036] Step 1: The same as in Example 1;

[0037] Step 2: PPS quaternization: 1 g of PPS-Cl fiber, 0.15 mol of pyridine, and 20 mL of acetonitrile were added into an autoclave, and after reaction in a 100 °C oven for 24 h, the fiber was removed and cleaned with ethanol, and after drying, quaternary ammonium PPS fiber PPS-PQA was obtained;

[0038] Step 3: PPS-supported ionic liquid: 0.5 g of PPS-PQA fiber, 1.5 g of ZnCl2, and 20 mL of n-heptane were added into an autoclave, and after reaction in a 60 °C oven for 8 h, the fiber was removed and cleaned with n-heptane, and after drying in a 60 °C vacuum drying oven for 12 h, PPS-supported triethylamine ionic liquid fiber PPS-PQAZn was obtained;

[0039] Step 4: Catalytic synthesis of TCPP flame retardant: 30 mg of fiber catalyst PPS-TQAZn was added into 10 mmol (1.37 g) of phosphorus oxychloride, and heated and stirred until the temperature rose to 60 °C. Then 40 mmol (3.7 g) of propylene oxide was slowly added to the reaction system, and the reaction temperature was gradually increased to 80 °C. After the addition was completed, the reaction was continued at 80 °C for 5 h. After the reaction was completed, the fiber catalyst was removed, and the reaction liquid was concentrated at 80 °C and 0.1 mbar until no bubbles were generated, to obtain the TCPP flame retardant. The yield was 95%, and the acid value was less than 0.1 mg KOH / g.

[0040] Example 3

[0041] The method for synthesizing TCPP flame retardant by PPS-supported ionic liquid catalysis in this example is as follows:

[0042] Step 1: The same as in Example 1;

[0043] Step 2: PPS quaternization: In an autoclave, 1 g PPS-Cl fiber, 0.2 mol of N-methyl imidazole and 20 mL of acetonitrile were added, and after 24 h of reaction in a 90 °C oven, the fiber was removed and washed with ethanol, and after drying, quaternary ammonium PPS fiber PPS-PQA was obtained;

[0044] Step 3: PPS immobilized ionic liquid: In an autoclave, 0.5 g PPS-PQA fiber, 2 g ZnCl2 and 20 mL of n-heptane were added, and after 12 h of reaction in a 100 °C oven, the fiber was removed and washed with n-heptane, and after drying in a 60 °C vacuum drying oven for 12 h, PPS immobilized triethylamine ionic liquid fiber PPS-MQAZn was obtained;

[0045] Step 4: Catalytic synthesis of TCPP flame retardant: In 10 mmol (1.37 g) of phosphorus trichloride, 16 mg of fiber catalyst PPS-TQAZn was added, and heated and stirred until the temperature rose to 30 °C. Then 50 mmol (4.63 g) of propylene oxide was slowly added dropwise to the reaction system, and the reaction temperature was gradually increased to 60 °C. After the addition was completed, the reaction was continued at 60 °C for 5 h. After the reaction was completed, the fiber catalyst was removed, and the reaction liquid was concentrated at 60 °C and 0.1 mbar until no bubbles were generated, to obtain TCPP flame retardant. The yield was 92%, and the acid value was less than 0.1 mg KOH / g.

[0046] Comparative Example 1

[0047] This comparative example uses small molecule ZnCl2 instead of the catalyst of the present application to prepare TCPP, and the TCPP purification process uses traditional processes such as alkali washing and water washing, and the others are the same as Example 1. The yield of TCPP prepared is 87%, and the acid value is less than 0.1 mg KOH / g.

[0048] The products of the examples and comparative examples were subjected to stability tests at 60 °C, and the stability test method was as follows: 500 g of sample was taken in a sample bottle and placed in a constant temperature 60 °C oven, and after 7 days, it was taken out for detection. The results of the above examples and comparative examples are shown in Table 1.

[0049] Taking PPS-PQZn as an example, the results of the recycling performance of the PPS immobilized ionic liquid catalyst are shown in Table 2.

[0050] Table 1 Results of PPS immobilized ionic liquid catalytic synthesis of TCPP flame retardant

[0051]

[0052] Table 2 Results of PPS-PQZn catalyst recycling

[0053] Cycles 1 2 3 4 5 6 7 8 Yield (%) 95 95 93 94 93 93 92 92

[0054] According to the results of the above Table 1 and Table 2, it can be known that the present application can realize the simplification of the preparation process of TCPP flame retardant, avoid the phenomena of reverse acid and reverse turbidity in the storage process, and also realize the recycling of the catalyst, reduce the pollution and the use cost, and be more in line with the requirements of green chemistry.

[0055] The above shows and describes the basic principles and main features of the present application and the advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a PPS-supported ionic liquid fiber catalyst, characterized in that: The following steps are involved: (1) Chloromethylation of PPS fiber: PPS fiber, paraformaldehyde, tin tetrachloride, trimethylsilyl chloride and 1,2-dichloroethane were added to a hydrothermal reactor. After reacting in an oven for a period of time, the fiber was taken out and cleaned with ethanol. After drying, the chloromethylated PPS fiber PPS-Cl was obtained. (2) PPS quaternization: Chloromethylated PPS fiber PPS-Cl and tertiary amine acetonitrile solution were added to a hydrothermal reactor. After reacting in an oven for a period of time, the fiber was taken out and cleaned with ethanol. After drying, the quaternized PPS fiber PPS-QA was obtained. (3) PPS-supported ionic liquid: Add quaternized PPS fiber PPS-QA and ZnCl2 aqueous solution into a hydrothermal reactor, react in an oven at a certain temperature for a period of time, take out the fiber and clean it with ethanol, and dry it in a vacuum drying oven to obtain PPS-supported ionic liquid fiber PPS-QAZn, i.e., PPS-supported ionic liquid fiber catalyst; In the step (1), the mass ratio of the PPS fiber to the reaction solution is 1:20-1:80, the reaction solution is composed of paraformaldehyde, tin tetrachloride, trimethylchlorosilane and 1,2-dichloroethane solution, and the mass concentrations of paraformaldehyde, tin tetrachloride and trimethylchlorosilane in the reaction solution are 5-15%, 8-20% and 5-15%, respectively; the reaction temperature in the step (1) is 50-100°C, and the reaction time is 24-72 h; In the step (2), the mass ratio of the PPS-Cl fiber to the acetonitrile solution of the tertiary amine is 1:10-1:50, and the concentration of the acetonitrile solution of the tertiary amine is 3-10 mol / L; in the step (2), the reaction temperature is 50-100° C., and the reaction time is 12-36 h.

2. The method for preparing the PPS-supported ionic liquid fiber catalyst according to claim 1, wherein: The tertiary amine in step (2) is triethylamine.

3. The method for preparing the PPS-supported ionic liquid fiber catalyst according to claim 1, wherein: In the step (3), the mass ratio of the PPS-QA fiber to the ZnCl2 aqueous solution is 1:20-1:100, and the mass ratio of ZnCl2 to PPS-QA is 1:1-1:

3.

4. The method for preparing the PPS-supported ionic liquid fiber catalyst according to claim 1, wherein: In the step (3), the reaction temperature is 60-150° C., and the reaction time is 2-48 h.

5. The PPS-supported ionic liquid fiber catalyst prepared according to the preparation method according to any one of claims 1 to 4.

6. Use of the PPS-supported ionic liquid fiber catalyst in the catalytic synthesis of TCPP flame retardant according to claim 5, characterized in that: The PPS immobilized ionic liquid fiber catalyst is added to phosphorus oxychloride or phosphorus trichloride, heated and stirred to a certain temperature, and then propylene oxide is slowly added dropwise to the reaction system, and the reaction temperature is kept gradually increasing. After the dropwise addition is completed, the temperature is continued to be maintained and the reaction is carried out for a certain time. After the reaction is completed, the PPS immobilized ionic liquid fiber catalyst is taken out, and the reaction liquid is concentrated under reduced pressure at the reaction temperature to obtain the TCPP flame retardant.

7. The use according to claim 6, characterized in that: The molar ratio of propylene oxide to phosphorus oxychloride or phosphorus trichloride is 1:1-5:1, and the amount of PPS immobilized ionic liquid fiber catalyst is 0.001%-2.0% of the total weight of the reaction raw materials.

8. The use according to claim 6, characterized in that: Before adding propylene oxide, the temperature of phosphorus oxychloride or phosphorus trichloride is controlled at 30°C-100°C. After adding propylene oxide, the final reaction temperature is 50°C-120°C, and the reaction time is 2-12 hours. The reduced pressure concentration pressure is 0.01-0.1 mbar.

Images