A process for the combined production of diphenylphosphine oxide and 1,2-bis(diphenylphosphinoyl)ethane

Abstract

The application provides a combined production method of diphenylphosphine oxide and 1,2-bis(diphenylphosphineoxy)ethane, and belongs to the technical field of organic synthesis. The combined production method of diphenylphosphine oxide and 1,2-bis(diphenylphosphineoxy)ethane comprises four steps of preparing diphenylchlorophosphine crude product, hydrolysis extraction, distillation and refining of diphenylphosphine oxide, and preparation of 1,2-bis(diphenylphosphineoxy)ethane. The purity of the obtained diphenylphosphine oxide is 99.1-99.6%, the yield of the diphenylphosphine oxide is 97.2-98.3%, the purity of the 1,2-bis(diphenylphosphineoxy)ethane is 98.9-99.3%, and the yield of the 1,2-bis(diphenylphosphineoxy)ethane is 96.7-98.0%.

Description

Technical Field

[0001] This invention relates to a method for the combined production of diphenylphosphine oxide and 1,2-bis(diphenylphosphoxy)ethane, belonging to the field of organic synthesis technology. Background Technology

[0002] Diphenylphosphine oxide and 1,2-bis(diphenylphosphoxy)ethane are two organophosphorus compounds with great practical value. Diphenylphosphine oxide has the chemical formula C2. 12 H 11 OP (phosphine oxide), commonly used in flame retardants, catalysts, and organic synthesis intermediates, possesses high thermal and chemical stability due to its molecular structure, which includes one phosphorus atom bonded to two phenyl groups and one oxygen atom. Diphenylphosphine oxide is widely used in the flame retardant field, particularly in high-performance electronic materials such as copper clad laminates (CCL), flexible copper clad laminates (FCCL), and FR4, effectively reducing the dielectric constant and coefficient of thermal expansion while providing excellent flame retardant properties. 1,2-Bis(diphenylphosphoxy)ethane is a novel halogen-free, environmentally friendly flame retardant, primarily used as an additive. It can be used for flame-retardant modification of transparent polymer resins such as epoxy resins, PET, and PETG, as well as nylon spun films. It features high thermal stability, a moderate melting point, does not affect the transparency and spinnability of materials, does not migrate or precipitate, has good flame-retardant effects, low smoke emission, low mold corrosion, excellent electrical properties, and fully complies with EU RoHS and REACH regulations. Therefore, the market for 1,2-bis(diphenylphosphoxy)ethane in the flame retardant field continues to expand.

[0003] There are three main methods for synthesizing diphenylphosphine oxide. Method 1 uses POCl3 as a raw material, which undergoes Friedel-Crafts alkylation followed by reduction with lithium aluminum hydride to obtain the target compound. Method 2 uses diethyl phosphite as a raw material, which undergoes Grignard reagent reaction to generate the product. Method 3 uses PCl3 as a raw material, which undergoes Friedel-Crafts alkylation followed by appropriate hydrolysis to obtain the target compound. However, the purification of the intermediate Ph2PCl is relatively difficult, and the yield is low, generally below 40.0%. The catalysts involved in methods 1 and 2 above, lithium aluminum hydride and Grignard reagents, are expensive and highly reactive, requiring stringent storage conditions and posing significant safety risks. Therefore, method 3 is more commonly used in industrial production to prepare diphenylphosphine oxide. However, the biggest problem with method 3 is the difficulty in purifying the intermediate Ph2PCl, resulting in low yield. Therefore, there is an urgent need to develop a method that can prepare diphenylphosphine oxide in high yield using PCl3 as a raw material through Friedel-Crafts alkylation. Moreover, 1,2-bis(diphenylphosphoxy)ethane, as a high-value derivative of diphenylphosphine oxide, would undoubtedly have a very direct effect on improving the utilization rate of phosphorus and reducing the overall production cost of these two organophosphorus compounds if it could be produced in high yield during the preparation of diphenylphosphine oxide.

[0004] Chinese patent CN116987117A discloses a method for preparing diphenylphosphine oxide and its application, comprising the following steps: under an inert gas atmosphere, triphenylphosphine oxide (Ph3PO) is mixed with metallic sodium and a polyol compound in a nonpolar hydrocarbon solvent, and the mixture is subjected to a complete reaction at a temperature of 60℃~150℃ to generate a reactive intermediate (Ph2PONa), benzene, and a sodium polyol salt. After the reaction, the Ph2PONa intermediate can be further reacted with water to obtain diphenylphosphine oxide (Ph2P(O)H). The conditions for preparing diphenylphosphine oxide in this patent are quite demanding. Firstly, it requires an inert atmosphere for protection; secondly, the metallic sodium used is a highly dangerous and flammable metal. Although the yield is relatively high, it is difficult to scale up for industrial production. Moreover, using triphenylphosphine oxide, an industrial byproduct, as a raw material, the entire process cannot achieve the co-production of 1,2-bis(diphenylphosphoxy)ethane.

[0005] Chinese patent CN117229318A discloses a method for the combined production of diphenylphosphine oxide and diphenylphosphonic acid. The method involves using diphenylphosphine chloride as a raw material, reacting it with water and an alkaline substance to generate diphenylphosphine oxide, extracting and washing to obtain an organic phase containing diphenylphosphine oxide, followed by vacuum distillation and cooling crystallization to obtain a diphenylphosphine oxide product and a mother liquor. The mother liquor is mixed with water and refluxed to convert diphenylphosphine oxide into diphenylphosphonic acid. The final product is then concentrated and cooled crystallized to obtain diphenylphosphonic acid. However, this patent does not prepare diphenylphosphine oxide from the most basic raw materials, and the highest yield of diphenylphosphine oxide is only 35%.

[0006] As can be seen above, the current method for preparing diphenylphosphine oxide from phosphorus trichloride via Friedel-Crafts alkylation still suffers from the prominent problem of low yield. Therefore, developing a method for preparing diphenylphosphine oxide with high yield from phosphorus trichloride and co-producing 1,2-bis(diphenylphosphoxy)ethane is a technological development idea with great practical significance and value. Summary of the Invention

[0007] To address the shortcomings of the existing technology, this invention provides a method for the combined production of diphenylphosphine oxide and 1,2-bis(diphenylphosphoxy)ethane, achieving the following objective: to prepare diphenylphosphine oxide in high yield using phosphorus trichloride as a raw material, and to co-produce 1,2-bis(diphenylphosphoxy)ethane.

[0008] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0009] The combined production method of diphenylphosphine oxide and 1,2-bis(diphenylphosphoxy)ethane includes four steps: preparing crude diphenylphosphine chloride, hydrolysis extraction, distillation purification of diphenylphosphine oxide, and preparing 1,2-bis(diphenylphosphoxy)ethane.

[0010] The following are further improvements to the above technical solution:

[0011] Step 1: Preparation of crude diphenylphosphine chloride

[0012] Benzene, phosphorus trichloride, and anhydrous aluminum trichloride were added to a reaction vessel and stirred until the anhydrous aluminum trichloride was completely dissolved. The temperature was raised and kept constant to the reaction temperature. Under constant temperature reflux, the reaction was stirred until complete. The mixture was then cooled to room temperature, a complex decomplexing agent was added, and the mixture was stirred to decomplex. The mixture was then allowed to stand until the decomplexation was complete, and crude diphenylphosphine chloride was obtained.

[0013] The composite anti-complexing agent is composed of trimethyl phosphoroacetate and triisopropyl phosphite;

[0014] The mass ratio of trimethyl phosphoroacetate to triisopropyl phosphite is 20-60:13;

[0015] The mass ratio of benzene, phosphorus trichloride, anhydrous aluminum trichloride, and the composite anti-complexing agent is 80~200:30~95:15~50:9~20;

[0016] The reaction temperature is 75~95℃;

[0017] The stirring reaction was complete, the stirring rate was 500-900 rpm, and the stirring reaction time was 7-11 hours;

[0018] The stirring and decomplexing process is carried out at a stirring rate of 500-900 rpm for 3-6 hours.

[0019] The settling time is 8 to 13 hours.

[0020] Step 2, hydrolysis extraction

[0021] Under controlled water temperature and constant stirring, crude diphenylphosphine chloride was added dropwise to pure water. After the addition was complete, the mixture was stirred thoroughly to hydrolyze completely, and then a hydrolysate was obtained. A composite extraction solvent was then added to the hydrolysate, and after extraction and washing, an organic phase containing diphenylphosphine oxide was obtained.

[0022] The composite extraction solvent is composed of petroleum ether, cyclohexane, and 1,2-dichloroethane;

[0023] The mass ratio of petroleum ether, cyclohexane, and 1,2-dichloroethane is 10~45:20~80:60~190;

[0024] The mass ratio of crude diphenylphosphine chloride to pure water is 30~60:179;

[0025] The crude diphenylphosphine chloride is added dropwise to pure water at a rate of 30-200 g / min.

[0026] The extraction process involves using a composite extraction solvent at a mass of 30-50% of the hydrolysate mass for each extraction, and performing 3-5 extractions.

[0027] The washing process involves combining the extracted organic phases and washing them with pure water 2-3 times, with the mass of pure water used in each wash being equal to the mass of the organic phase being washed.

[0028] The temperature of the pure water is controlled between 0 and 10°C.

[0029] The continuous stirring is carried out at a speed of 400-900 rpm.

[0030] The stirring process is thorough and complete, with a stirring rate of 400-900 rpm and a stirring and hydrolysis time of 0.8-1.5 hours.

[0031] Step 3: Distillation and purification of diphenylphosphine oxide

[0032] The organic phase containing diphenylphosphine oxide is distilled under reduced pressure to obtain purified diphenylphosphine oxide. The distilled organic solvent has the same composition as the composite extraction solvent and is reused as the composite extraction solvent.

[0033] The vacuum distillation is carried out at a pressure of -90 to -75 kPa and a temperature of 70 to 85 °C.

[0034] Step 4: Preparation of 1,2-bis(diphenylphosphoxy)ethane

[0035] Sodium hydroxide aqueous solution, main catalyst, and co-catalyst were added to an organic phase containing diphenylphosphine oxide. The temperature was raised and kept constant to the reaction temperature. After the reaction was completed by stirring, the mixture was cooled to room temperature and filtered. The filtrate was washed and dried to obtain 1,2-bis(diphenylphosphoxy)ethane.

[0036] The main catalyst is tetrabutylammonium bromide;

[0037] The cocatalyst is 1-butyl-3-methylimidazolium dibutyl phosphate salt;

[0038] The sodium hydroxide aqueous solution has a sodium hydroxide concentration of 25-35 wt%.

[0039] The mass ratio of the organic phase containing diphenylphosphine oxide, the sodium hydroxide aqueous solution, the main catalyst, and the co-catalyst is 100~230:70~150:10~40:1~5;

[0040] The reaction temperature is 70~90℃;

[0041] The stirring reaction was complete, the stirring rate was 400~1000 rpm, and the reaction time was 7~13 hours;

[0042] The washing process involves washing with 1,2-dichloroethane 2 to 3 times, with the mass of 1,2-dichloroethane used in each wash being equal to the mass of the solid being washed.

[0043] The drying process involves a drying temperature of 80-100℃ and a drying time of 10-15 hours.

[0044] Compared with the prior art, the present invention achieves the following beneficial effects:

[0045] 1. This invention uses benzene and phosphorus trichloride as raw materials to prepare the intermediate of diphenylphosphine oxide, namely diphenylphosphine chloride, under the catalysis of anhydrous aluminum trichloride. However, diphenylphosphine chloride readily forms a complex with anhydrous aluminum trichloride, which makes it difficult for diphenylphosphine chloride to be completely hydrolyzed in the hydrolysis extraction step, ultimately severely affecting the yield and purity of diphenylphosphine oxide. Therefore, in order to effectively prevent the formation of a complex between diphenylphosphine chloride and anhydrous aluminum trichloride, this invention introduces a composite decomposition agent composed of trimethyl phosphoroacetate and triisopropyl phosphite. The phosphoryl functional group in trimethyl phosphoroacetate and the phosphite functional group in triisopropyl phosphite have strong electronegativity and can form a stable complex with anhydrous aluminum trichloride, which is a Lewis acid with very strong electrophilicity, by relying on the charge effect. Therefore, the intermediate product diphenylphosphine chloride can undergo hydrolysis to the maximum extent, ultimately greatly improving the purity and yield of diphenylphosphine oxide.

[0046] 2. To improve the extraction yield and purity of diphenylphosphine oxide, this invention specifically designs a composite extraction solvent composed of petroleum ether, cyclohexane, and 1,2-dichloroethane. Diphenylphosphine oxide has relatively weak polarity. To achieve the best effect in co-production with 1,2-bis(diphenylphosphoxy)ethane, the optimal approach is to use only 1,2-dichloroethane as the extractant. This way, 1,2-dichloroethane serves both as the extraction solvent and as a single, high-concentration raw material in the preparation reaction of 1,2-bis(diphenylphosphoxy)ethane. However, diphenylphosphine oxide... Phosphorus is not very soluble in 1,2-dichloroethane, and it is difficult to improve the yield of diphenylphosphine oxide by using only 1,2-dichloroethane. Therefore, this invention uses petroleum ether and cyclohexane, two solvents with relatively weak polarity, to improve the extraction efficiency of diphenylphosphine oxide. This can improve the yield of diphenylphosphine oxide without affecting the subsequent reaction of 1,2-dichloroethane and diphenylphosphine oxide to produce 1,2-bis(diphenylphosphoxy)ethane under alkaline conditions, because petroleum ether and cyclohexane are relatively inert organic solvents.

[0047] 3. In order to accelerate the reaction rate of diphenylphosphine oxide and 1,2-dichloroethane and increase the yield of 1,2-bis(diphenylphosphoxy)ethane, this invention adds a co-catalyst of 1-butyl-3-methylimidazolium phosphate salt to the phase transfer catalyst tetrabutylammonium bromide. This phosphate salt ionic liquid containing an imidazolium ring has a very strong ion solvation effect and can form a phase interface transition layer with a very large area at the oil-water interface. Therefore, it can work with tetrabutylammonium bromide to accelerate the ion transfer rate between the oil and water phases, thereby maximizing the rate of chloride ion migration into the aqueous phase, promoting the degree and rate of the reaction equilibrium shifting in the positive direction, and ultimately significantly improving the yield and purity of 1,2-bis(diphenylphosphoxy)ethane.

[0048] 4. The purity of the diphenylphosphine oxide obtained by this invention is 99.1-99.6%, and the yield of diphenylphosphine oxide is 97.2-98.3%. The purity of 1,2-bis(diphenylphosphoxy)ethane is 98.9-99.3%, and the yield of 1,2-bis(diphenylphosphoxy)ethane is 96.7-98.0%. Attached Figure Description

[0049] Figure 1 This is a flowchart of the synthesis process of the present invention. Detailed Implementation

[0050] The preferred embodiments of the present invention are described below. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0051] Example 1: A method for the combined production of diphenylphosphine oxide and 1,2-bis(diphenylphosphoxy)ethane

[0052] Step 1: Preparation of crude diphenylphosphine chloride

[0053] Benzene, phosphorus trichloride, and anhydrous aluminum trichloride were added to a reaction vessel and stirred until the anhydrous aluminum trichloride was completely dissolved. The temperature was raised and kept constant to the reaction temperature. Under constant temperature reflux, the reaction was stirred until complete. The mixture was then cooled to room temperature, a complex decomplexing agent was added, and the mixture was stirred to decomplex. The mixture was then allowed to stand until the decomplexation was complete, and crude diphenylphosphine chloride was obtained.

[0054] The composite anti-complexing agent is composed of trimethyl phosphoroacetate and triisopropyl phosphite;

[0055] The mass ratio of trimethyl phosphoroacetate to triisopropyl phosphite is 45:13;

[0056] The mass ratio of benzene, phosphorus trichloride, anhydrous aluminum trichloride, and the composite anti-complexing agent is 140:65:40:17.

[0057] The reaction temperature is 87°C;

[0058] The stirring reaction was complete, the stirring rate was 700 rpm, and the stirring reaction time was 9 hours;

[0059] The stirring and decomplexing process was carried out at a stirring rate of 600 rpm for 5 hours.

[0060] The settling period is 11 hours.

[0061] Step 2, hydrolysis extraction

[0062] Under controlled water temperature and constant stirring, crude diphenylphosphine chloride was added dropwise to pure water. After the addition was complete, the mixture was stirred thoroughly to hydrolyze completely, and then a hydrolysate was obtained. A composite extraction solvent was then added to the hydrolysate, and after extraction and washing, an organic phase containing diphenylphosphine oxide was obtained.

[0063] The composite extraction solvent is composed of petroleum ether, cyclohexane, and 1,2-dichloroethane;

[0064] The mass ratio of petroleum ether, cyclohexane, and 1,2-dichloroethane is 30:50:110.

[0065] The mass ratio of crude diphenylphosphine chloride to pure water is 45:179.

[0066] The crude diphenylphosphine chloride was added dropwise to pure water at a rate of 110 g / min.

[0067] The extraction process involves using a composite extraction solvent at a mass of 40% of the hydrolysate mass for each extraction, and the extraction is performed four times.

[0068] The washing process involves combining the extracted organic phases and washing them twice with pure water, with the mass of pure water used in each wash being equal to the mass of the organic phase being washed.

[0069] The temperature of the pure water is controlled at 3°C.

[0070] The continuous stirring is carried out at a stirring rate of 600 revolutions per minute.

[0071] The stirring was thorough and the hydrolysis was complete. The stirring speed was 600 rpm and the stirring and hydrolysis time was 1 hour.

[0072] Step 3: Distillation and purification of diphenylphosphine oxide

[0073] The organic phase containing diphenylphosphine oxide is distilled under reduced pressure to obtain purified diphenylphosphine oxide. The distilled organic solvent has the same composition as the composite extraction solvent and is reused as the composite extraction solvent.

[0074] The vacuum distillation is carried out at a pressure of -85 kPa and a temperature of 75°C.

[0075] Step 4: Preparation of 1,2-bis(diphenylphosphoxy)ethane

[0076] Sodium hydroxide aqueous solution, main catalyst, and co-catalyst were added to an organic phase containing diphenylphosphine oxide. The temperature was raised and kept constant to the reaction temperature. After the reaction was completed by stirring, the mixture was cooled to room temperature and filtered. The filtrate was washed and dried to obtain 1,2-bis(diphenylphosphoxy)ethane.

[0077] The main catalyst is tetrabutylammonium bromide;

[0078] The cocatalyst is 1-butyl-3-methylimidazolium dibutyl phosphate salt;

[0079] The sodium hydroxide aqueous solution has a sodium hydroxide concentration of 29 wt%.

[0080] The mass ratio of the organic phase containing diphenylphosphine oxide, the aqueous sodium hydroxide solution, the main catalyst, and the co-catalyst is 200:120:20:4.

[0081] The reaction temperature is 85°C;

[0082] The stirring reaction was complete at a stirring rate of 700 rpm for 11 hours.

[0083] The washing process involves washing twice with 1,2-dichloroethane, with the mass of 1,2-dichloroethane used in each wash being equal to the mass of the solid being washed.

[0084] The drying process involves a drying temperature of 95°C and a drying time of 12 hours.

[0085] Example 2: A method for the combined production of diphenylphosphine oxide and 1,2-bis(diphenylphosphoxy)ethane

[0086] Step 1: Preparation of crude diphenylphosphine chloride

[0087] Benzene, phosphorus trichloride, and anhydrous aluminum trichloride were added to a reaction vessel and stirred until the anhydrous aluminum trichloride was completely dissolved. The temperature was raised and kept constant to the reaction temperature. Under constant temperature reflux, the reaction was stirred until complete. The mixture was then cooled to room temperature, a complex decomplexing agent was added, and the mixture was stirred to decomplex. The mixture was then allowed to stand until the decomplexation was complete, and crude diphenylphosphine chloride was obtained.

[0088] The composite anti-complexing agent is composed of trimethyl phosphoroacetate and triisopropyl phosphite;

[0089] The mass ratio of trimethyl phosphoroacetate to triisopropyl phosphite is 20:13;

[0090] The mass ratio of benzene, phosphorus trichloride, anhydrous aluminum trichloride, and the composite anti-complexing agent is 80:30:15:9;

[0091] The reaction temperature is 75°C;

[0092] The stirring reaction was complete, the stirring rate was 500 rpm, and the stirring reaction time was 7 hours;

[0093] The stirring and decomplexing process was carried out at a stirring rate of 500 rpm for 3 hours.

[0094] The settling time is 8 hours.

[0095] Step 2, hydrolysis extraction

[0096] Under controlled water temperature and constant stirring, crude diphenylphosphine chloride was added dropwise to pure water. After the addition was complete, the mixture was stirred thoroughly to hydrolyze completely, and then a hydrolysate was obtained. A composite extraction solvent was then added to the hydrolysate, and after extraction and washing, an organic phase containing diphenylphosphine oxide was obtained.

[0097] The composite extraction solvent is composed of petroleum ether, cyclohexane, and 1,2-dichloroethane;

[0098] The mass ratio of petroleum ether, cyclohexane, and 1,2-dichloroethane is 10:20:60.

[0099] The mass ratio of crude diphenylphosphine chloride to pure water is 30:179.

[0100] The crude diphenylphosphine chloride was added dropwise to pure water at a rate of 30 g / min.

[0101] The extraction process involves using a composite extraction solvent at a mass of 30% of the hydrolysate mass for each extraction, and performing three extractions in total.

[0102] The washing process involves combining the extracted organic phases and washing them twice with pure water, with the mass of pure water used in each wash being equal to the mass of the organic phase being washed.

[0103] The temperature of the pure water is controlled at 0℃.

[0104] The continuous stirring is carried out at a stirring rate of 400 revolutions per minute.

[0105] The stirring was thorough and the hydrolysis was complete. The stirring speed was 400 rpm and the hydrolysis time was 0.8 hours.

[0106] Step 3: Distillation and purification of diphenylphosphine oxide

[0107] The organic phase containing diphenylphosphine oxide is distilled under reduced pressure to obtain purified diphenylphosphine oxide. The distilled organic solvent has the same composition as the composite extraction solvent and is reused as the composite extraction solvent.

[0108] The vacuum distillation is carried out at a pressure of -90 kPa and a temperature of 70 °C.

[0109] Step 4: Preparation of 1,2-bis(diphenylphosphoxy)ethane

[0110] Sodium hydroxide aqueous solution, main catalyst, and co-catalyst were added to an organic phase containing diphenylphosphine oxide. The temperature was raised and kept constant to the reaction temperature. After the reaction was completed by stirring, the mixture was cooled to room temperature and filtered. The filtrate was washed and dried to obtain 1,2-bis(diphenylphosphoxy)ethane.

[0111] The main catalyst is tetrabutylammonium bromide;

[0112] The cocatalyst is 1-butyl-3-methylimidazolium dibutyl phosphate salt;

[0113] The sodium hydroxide aqueous solution has a sodium hydroxide concentration of 25 wt%.

[0114] The mass ratio of the organic phase containing diphenylphosphine oxide, the aqueous sodium hydroxide solution, the main catalyst, and the co-catalyst is 100:70:10:1;

[0115] The reaction temperature is 70°C;

[0116] The stirring reaction was complete at a stirring rate of 400 rpm for 7 hours.

[0117] The washing process involves washing twice with 1,2-dichloroethane, with the mass of 1,2-dichloroethane used in each wash being equal to the mass of the solid being washed.

[0118] The drying process involves a drying temperature of 80°C and a drying time of 10 hours.

[0119] Example 3: A method for the combined production of diphenylphosphine oxide and 1,2-bis(diphenylphosphoxy)ethane

[0120] Step 1: Preparation of crude diphenylphosphine chloride

[0121] Benzene, phosphorus trichloride, and anhydrous aluminum trichloride were added to a reaction vessel and stirred until the anhydrous aluminum trichloride was completely dissolved. The temperature was raised and kept constant to the reaction temperature. Under constant temperature reflux, the reaction was stirred until complete. The mixture was then cooled to room temperature, a complex decomplexing agent was added, and the mixture was stirred to decomplex. The mixture was then allowed to stand until the decomplexation was complete, and crude diphenylphosphine chloride was obtained.

[0122] The composite anti-complexing agent is composed of trimethyl phosphoroacetate and triisopropyl phosphite;

[0123] The mass ratio of trimethyl phosphoroacetate to triisopropyl phosphite is 60:13;

[0124] The mass ratio of benzene, phosphorus trichloride, anhydrous aluminum trichloride, and the complex anti-complexing agent is 200:95:50:20.

[0125] The reaction temperature is 95°C;

[0126] The stirring reaction was complete, the stirring rate was 900 rpm, and the stirring reaction time was 11 hours;

[0127] The stirring and decomplexing process was carried out at a stirring rate of 900 rpm for 6 hours.

[0128] The settling time is 13 hours.

[0129] Step 2, hydrolysis extraction

[0130] Under controlled water temperature and constant stirring, crude diphenylphosphine chloride was added dropwise to pure water. After the addition was complete, the mixture was stirred thoroughly to hydrolyze completely, and then a hydrolysate was obtained. A composite extraction solvent was then added to the hydrolysate, and after extraction and washing, an organic phase containing diphenylphosphine oxide was obtained.

[0131] The composite extraction solvent is composed of petroleum ether and cyclohexane;

[0132] The mass ratio of petroleum ether, cyclohexane, and 1,2-dichloroethane is 45:80:190;

[0133] The mass ratio of crude diphenylphosphine chloride to pure water is 60:179;

[0134] The crude diphenylphosphine chloride was added dropwise to pure water at a rate of 200 g / min.

[0135] The extraction process involves using a composite extraction solvent at a mass of 50% of the hydrolysate mass for each extraction, and performing five extractions in total.

[0136] The washing process involves combining the extracted organic phases and washing them three times with pure water, with the mass of pure water used in each wash being equal to the mass of the organic phase being washed.

[0137] The temperature of the pure water is controlled at 10℃.

[0138] The continuous stirring is carried out at a stirring rate of 900 revolutions per minute.

[0139] The stirring was thorough and the hydrolysis was complete. The stirring speed was 900 rpm and the hydrolysis time was 1.5 hours.

[0140] Step 3: Distillation and purification of diphenylphosphine oxide

[0141] The organic phase containing diphenylphosphine oxide is distilled under reduced pressure to obtain purified diphenylphosphine oxide. The distilled organic solvent has the same composition as the composite extraction solvent and is reused as the composite extraction solvent.

[0142] The vacuum distillation is carried out at a pressure of -75 kPa and a temperature of 85°C.

[0143] Step 4: Preparation of 1,2-bis(diphenylphosphoxy)ethane

[0144] Sodium hydroxide aqueous solution, main catalyst, and co-catalyst were added to an organic phase containing diphenylphosphine oxide. The temperature was raised and kept constant to the reaction temperature. After the reaction was completed by stirring, the mixture was cooled to room temperature and filtered. The filtrate was washed and dried to obtain 1,2-bis(diphenylphosphoxy)ethane.

[0145] The main catalyst is tetrabutylammonium bromide;

[0146] The cocatalyst is 1-butyl-3-methylimidazolium dibutyl phosphate salt;

[0147] The sodium hydroxide aqueous solution has a sodium hydroxide concentration of 35 wt%.

[0148] The mass ratio of the organic phase containing diphenylphosphine oxide, the aqueous sodium hydroxide solution, the main catalyst, and the co-catalyst is 230:150:40:5.

[0149] The reaction temperature is 90°C;

[0150] The stirring reaction was complete at a stirring rate of 1000 rpm for 13 hours.

[0151] The washing process involves washing three times with 1,2-dichloroethane, with the mass of 1,2-dichloroethane used in each wash being equal to the mass of the solid being washed.

[0152] The drying process is carried out at a temperature of 100°C for 15 hours.

[0153] Comparative Example 1: Based on Example 1, in step 1, the preparation of crude diphenylphosphine chloride, no complexing agent was added. The specific operation is as follows:

[0154] Step 1: Preparation of crude diphenylphosphine chloride

[0155] Benzene, phosphorus trichloride, and anhydrous aluminum trichloride were added to a reaction vessel and stirred until the anhydrous aluminum trichloride was completely dissolved. The temperature was then raised and kept constant to the reaction temperature. Under constant temperature reflux, the reaction was stirred until complete and then cooled to room temperature to obtain crude diphenylphosphine chloride. Other operations were the same as in Example 1.

[0156] Steps 2, 3, and 4 are the same as in Example 1.

[0157] Comparative Example 2: Based on Example 1, in step 1, the preparation of crude diphenylphosphine chloride, triisopropyl phosphite was not added to the composite complexing agent; the complexing agent was only trimethyl phosphoroacetate. 17 parts of the composite complexing agent were replaced with 17 parts of trimethyl phosphoroacetate in equal amounts. The specific operation is as follows:

[0158] Step 1: Preparation of crude diphenylphosphine chloride

[0159] The compound anti-complexing agent does not contain triisopropyl phosphite. Instead, 17 parts of the compound anti-complexing agent are replaced with 17 parts of trimethyl phosphoroacetate. Other operations are the same as in Example 1.

[0160] Steps 2, 3, and 4 are the same as in Example 1.

[0161] Comparative Example 3: Based on Example 1, in step 1, the preparation of crude diphenylphosphine chloride, trimethyl phosphoroacetate was not added to the composite complexing agent, and the complexing agent was only triisopropyl phosphite. 17 parts of the composite complexing agent were replaced with 17 parts of triisopropyl phosphite in equal amounts. The specific operation is as follows:

[0162] Step 1: Preparation of crude diphenylphosphine chloride

[0163] The compound complex unblocking agent does not contain trimethyl phosphoroacetate. Instead, 17 parts of the compound complex unblocking agent are replaced with 17 parts of trimethyl phosphoroacetate. Other operations are the same as in Example 1.

[0164] Steps 2, 3, and 4 are the same as in Example 1.

[0165] Comparative Example 4: Based on Example 1, in step 2, hydrolysis extraction, petroleum ether was not added to the composite extraction solvent. Instead, 30 parts of petroleum ether were replaced with 30 parts of cyclohexane. The specific operation is as follows:

[0166] Step 1 is the same as in Example 1;

[0167] Step 2, hydrolysis extraction

[0168] Replace 30 parts of petroleum ether with 30 parts of cyclohexane, and perform the other operations as in Example 1;

[0169] Steps 3 and 4 are the same as in Example 1.

[0170] Comparative Example 5: Based on Example 1, in step 2, hydrolysis extraction, cyclohexane was not added to the composite extraction solvent; instead, 50 parts of cyclohexane were replaced with 50 parts of petroleum ether. The specific operation is as follows:

[0171] Step 1 is the same as in Example 1;

[0172] Step 2, hydrolysis extraction

[0173] Replace 50 parts of cyclohexane with 50 parts of petroleum ether, and perform the other operations as in Example 1;

[0174] Steps 3 and 4 are the same as in Example 1.

[0175] Comparative Example 6: Based on Example 1, in step 4, the preparation of 1,2-bis(diphenylphosphino)ethane, no co-catalyst was added, and 4 parts of co-catalyst were replaced with 4 parts of main catalyst in equal amounts. The specific operation is as follows:

[0176] Steps 1, 2, and 3 are the same as in Example 1;

[0177] Step 4: Preparation of 1,2-bis(diphenylphosphoxy)ethane

[0178] Replace 4 parts of the co-catalyst with 4 parts of the main catalyst in equal amounts, and perform the other operations as in Example 1.

[0179] Yield and purity:

[0180] In Examples 1-3 and Comparative Examples 1-6, the yield of diphenylphosphine oxide was calculated based on the amount of benzene and phosphorus trichloride added, and the yield of 1,2-bis(diphenylphosphoxy)ethane was calculated based on the amount of benzene, phosphorus trichloride, and 1,2-dichloroethane added. The purity of diphenylphosphine oxide and 1,2-bis(diphenylphosphoxy)ethane was determined by liquid chromatography.

[0181] The results are shown in Table 1:

[0182] Table 1

[0183] Diphenylphosphine oxide purity (%) Diphenylphosphine oxide yield (%) Purity (%) of 1,2-bis(diphenylphosphino)ethane Yield (%) of 1,2-bis(diphenylphosphino)ethane Example 1 99.5 97.2 99.3 97.4 Example 2 99.1 98.3 98.9 96.7 Example 3 99.6 98.0 99.2 98.0 Comparative Example 1 89.8 64.1 85.3 58.2 Comparative Example 2 93.5 70.6 89.4 64.3 Comparative Example 3 94.2 74.7 91.6 69.5 Comparative Example 4 99.2 81.5 98.3 76.7 Comparative Example 5 99.5 79.6 98.8 74.0 Comparative Example 6 99.3 98.2 95.7 80.5

[0184] As can be seen from the data in the table, in Examples 1-3, the purity of diphenylphosphine oxide was above 99%, and the yield was above 97%, while the purity of 1,2-bis(diphenylphosphoxy)ethane was above 98%, and the yield was above 96%. This indicates that the present invention prepared high-purity diphenylphosphine oxide with a very high yield, and the 1,2-bis(diphenylphosphoxy)ethane prepared in the co-production also had the characteristics of high yield and high purity. In Comparative Example 1, without the addition of the composite complex-uncoating agent in step 1 and the preparation of crude diphenylphosphine chloride, the purity and yield of the diphenylphosphine oxide and 1,2-bis(diphenylphosphoxy)ethane obtained in Comparative Example 1 decreased sharply. This indicates that the composite complex-uncoating agent... The composite solvent effectively de-complexes diphenylphosphine chloride with aluminum trichloride, allowing for complete hydrolysis of the de-complexed diphenylphosphine chloride during the hydrolysis extraction step. This de-complexed diphenylphosphine chloride is then extracted into the organic phase by the composite solvent, significantly improving the purity and yield of diphenylphosphine oxide and 1,2-bis(diphenylphosphoxy)ethane. In Comparative Examples 2 and 3, where the composite de-complexing agent did not contain triisopropyl phosphite or trimethyl phosphoroacetate, the purity and yield of diphenylphosphine oxide and 1,2-bis(diphenylphosphoxy)ethane were significantly lower than in Example 1, but better than in Comparative Example 1. This indicates that the triisopropyl phosphite and trimethyl phosphoroacetate... The two substances, trimethyl ester and cyclohexane, have a very good synergistic effect in breaking the complexation between diphenylphosphine chloride and aluminum trichloride. Adding only one of these substances is insufficient to fully break the complexation. In Comparative Examples 4 and 5, in step 2 and the hydrolysis extraction, the composite extraction solvent did not contain petroleum ether or cyclohexane, respectively. In these two comparative examples, the purity of diphenylphosphine oxide and 1,2-bis(diphenylphosphoxy)ethane was not significantly different from that in Example 1, but the yields of diphenylphosphine oxide and 1,2-bis(diphenylphosphoxy)ethane were significantly reduced. This indicates that in the composite extraction solvent composed of petroleum ether, cyclohexane, and 1,2-dichloroethane, the synergistic effect of petroleum ether and cyclohexane is not sufficient. Both oil ether and cyclohexane are indispensable, as these two substances play a crucial synergistic role in improving the extraction efficiency of diphenylphosphine oxide. In Comparative Example 6, without the addition of a co-catalyst in step 4, the preparation of 1,2-bis(diphenylphosphoxy)ethane, the purity of 1,2-bis(diphenylphosphoxy)ethane in Comparative Example 6 decreased significantly, and the yield dropped drastically to 80.5%. This indicates that the co-catalyst 1-butyl-3-methylimidazolium phosphate dibutyl ester has a very good synergistic effect on the main catalyst tetrabutylammonium bromide, promoting the reaction degree between diphenylphosphine oxide and 1,2-dichloroethane, thereby significantly increasing the yield of 1,2-bis(diphenylphosphoxy)ethane.

[0185] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for the combined production of diphenylphosphine oxide and 1,2-bis(diphenylphosphoxy)ethane, characterized in that: The combined production method of diphenylphosphine oxide and 1,2-bis(diphenylphosphoxy)ethane includes four steps: preparing crude diphenylphosphine chloride, hydrolysis extraction, distillation purification of diphenylphosphine oxide, and preparing 1,2-bis(diphenylphosphoxy)ethane. To prepare crude diphenylphosphine chloride, benzene, phosphorus trichloride, and anhydrous aluminum trichloride are added to a reaction vessel and stirred until the anhydrous aluminum trichloride is completely dissolved. The temperature is then raised and kept constant to the reaction temperature. Under constant temperature reflux, the reaction is stirred until complete. The mixture is then cooled to room temperature, a composite decomplexing agent is added, and the mixture is stirred to decomplex. The mixture is then allowed to stand until the decomplex is complete, at which point crude diphenylphosphine chloride is obtained. The composite anti-complexing agent is composed of trimethyl phosphoroacetate and triisopropyl phosphite; The mass ratio of trimethyl phosphoroacetate to triisopropyl phosphite is 20-60:13; The hydrolysis extraction process involves controlling the temperature of pure water and adding crude diphenylphosphine chloride dropwise to pure water under continuous stirring. After the addition is complete, the mixture is stirred thoroughly to achieve complete hydrolysis, resulting in a hydrolysate. A composite extraction solvent is then added to the hydrolysate, and after extraction and washing, an organic phase containing diphenylphosphine oxide is obtained. The composite extraction solvent is composed of petroleum ether, cyclohexane, and 1,2-dichloroethane; The mass ratio of petroleum ether, cyclohexane, and 1,2-dichloroethane is 10~45:20~80:60~190; To prepare 1,2-bis(diphenylphosphoxy)ethane, sodium hydroxide aqueous solution, main catalyst, and co-catalyst are added to an organic phase containing diphenylphosphine oxide. The temperature is raised and kept constant to the reaction temperature. After the reaction is complete, the temperature is lowered to room temperature and filtered. The filtrate is washed and dried to obtain 1,2-bis(diphenylphosphoxy)ethane. The main catalyst is tetrabutylammonium bromide; The cocatalyst is 1-butyl-3-methylimidazolium dibutyl phosphate salt; The mass ratio of the organic phase containing diphenylphosphine oxide, the aqueous sodium hydroxide solution, the main catalyst, and the co-catalyst is 100~230:70~150:10~40:1~5.

2. The method for the combined production of diphenylphosphine oxide and 1,2-bis(diphenylphosphoxy)ethane according to claim 1, characterized in that: The distillation and purification of diphenylphosphine oxide involves distilling the organic phase containing diphenylphosphine oxide under reduced pressure to obtain purified diphenylphosphine oxide. The distilled organic solvent has the same composition as the composite extraction solvent and is reused as the composite extraction solvent.

3. The method for the combined production of diphenylphosphine oxide and 1,2-bis(diphenylphosphoxy)ethane according to claim 1, characterized in that: The mass ratio of benzene, phosphorus trichloride, anhydrous aluminum trichloride, and the composite anti-complexing agent is 80~200:30~95:15~50:9~20.

4. The method for the combined production of diphenylphosphine oxide and 1,2-bis(diphenylphosphoxy)ethane according to claim 1, characterized in that: The mass ratio of crude diphenylphosphine chloride to pure water is 30~60:

179.

5. The method for the combined production of diphenylphosphine oxide and 1,2-bis(diphenylphosphoxy)ethane according to claim 1, characterized in that: The sodium hydroxide aqueous solution has a sodium hydroxide concentration of 25-35 wt%.

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