Synthesis method of chlorinated spiro phosphate

Abstract

The invention relates to a synthetic method of chlorinated spiro phosphate. The chlorinated spirocyclic phosphate is formed by carrying out cyclization HCl removal reaction on phosphorus oxychloride and pentaerythritol in a trace amount of a solvent 1, 1, 2, 2-tetrachloroethane, the obtained chlorinated spirocyclic phosphate is high in purity, the yield can reach 74%, meanwhile, due to the fact that phosphorus oxychloride and pentaerythritol are added according to the amount of 2.1: 1, post-treatment of a reaction product is convenient, and the yield of the reaction product is high. And the problems of harm to the body of an operator and the environment caused by excessive phosphorus oxychloride and the like are reduced. The chlorinated spirocyclic phosphate can be used as an intermediate for synthesizing a halogen-free phosphorus-containing flame retardant to synthesize a batch of high-efficiency and low-toxicity phosphorus-containing flame retardants such as spirocyclic phosphate melamine salt, oligomer of spirocyclic phosphate and diamine, bromo-aryl spirocyclic phosphate and the like. Meanwhile, the molecular structure of the product contains a pentaerythritol skeleton structure, and a stable six-membered heterocyclic structure is formed by three elements of P, O, C and the like in the molecule of the chlorinated spirocyclic phosphate.

Description

Technical Field

[0001] The present application relates to a method for synthesizing a chlorinated spirocyclic phosphate, and belongs to the technical field of preparation of phosphorus-based flame retardant materials. Background Art

[0002] Traditional halogen flame retardants are one of the organic flame retardants with the largest output in the world. They are highly valued for their low addition amount, obvious flame retardant effect and moderate price. However, such flame retardants will release a large amount of corrosive gases and toxic smoke during combustion, which not only pollutes the environment but also causes harm to equipment and human body. Therefore, halogen-free flame retardant has become the main direction of flame retardant technology development in the world today. Intumescent flame retardants have attracted much attention due to their many advantages such as low smoke, low corrosion, high efficiency and environmental protection. At present, such flame retardants have been widely used as a general flame retardant in various polymers such as polyolefins and polyesters. However, intumescent flame retardants themselves also have certain disadvantages. One of them is that since the carbon source contains polyhydroxyl hydrophilic functional groups, its water resistance is poor, and long-term use will reduce the flame retardant effect. Therefore, synthesizing new carbon-forming compounds with good water resistance and high stability is an effective means to solve this problem.

[0003] On the one hand, the six-membered ring has a stable chair-type conformation, and the CC bond, CO bond and CH bond are all in a stable state without angular tension or torsional tension. The energy required to destroy the six-membered ring structure is greater than the energy required to destroy the linear structure. Therefore, cyclic phosphates have good thermal stability. On the other hand, the cyclic structure is very easy to form a cross-linked carbon layer when heated, so it has a high carbonization rate. In addition, chlorinated spirocyclic phosphates contain active reactive functional groups of acyl chloride, which can be used as flame retardant intermediates to prepare various types of flame retardants. Since 1963, Ratz et al. first synthesized the compound 3,9-dichloro-2,4,8,10-tetrachloro-3,9-diphospho-spiro-3,9-dioxo[5.5]undecane (SPDPC) and conducted corresponding research on its properties. Since then, many researchers have conducted further research on the properties and synthesis methods of this compound. U.S. Patent No. 3169863 reported a method for large-scale synthesis of chlorinated spirocyclic phosphates. Although a high purity and high yield of 3,9-dichloro-2,4,8,10-tetrachloro-3,9-diphosphospiro-3,9-dioxo[5.5]undecane (SPDPC) was obtained by reacting with a large excess of phosphorus oxychloride and pentaerythritol, the post-treatment process was complicated due to the introduction of a large excess of phosphorus oxychloride into the reaction system. At the same time, the high toxicity of phosphorus oxychloride would cause harm to operators and the environment. Yan Li et al. reported that using dichloroethane as solvent at 50-80°C and a 2:1 ratio of phosphorus oxychloride to pentaerythritol gave 3,9-dichloro-2,4,8,10-tetrachloro-3,9-diphosphaspiro-3,9-dioxo[5.5]undecane (SPDPC) with a high purity and a yield of 66%. However, under the same conditions, we found that the reaction would produce many by-products and pure 3,9-dichloro-2,4,8,10-tetrachloro-3,9-diphosphaspiro-3,9-dioxo[5.5]undecane (SPDPC) could not be obtained. The product contained the impurity 1-oxo-4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane (PEPA). A. Richard Horrocks et al. first reacted phosphorus oxychloride and pentaerythritol at a ratio of 2:1 at 90°C for 2 hours, then heated to 100°C and kept warm for 20 hours until no hydrogen chloride gas was released, and then added excess phosphorus oxychloride into the system and refluxed for 2 hours to obtain 3,9-dichloro-2,4,8,10-tetrachloro-3,9-diphospho-spiro-3,9-dioxy-[5.5]undecane (SPDPC) with high purity. Although the amount of phosphorus oxychloride used in this method is small, the reaction process is long and the reaction temperature is high, which is not conducive to large-scale production and application. The present invention relates to a novel method for synthesizing chlorinated spirocyclic phosphate [3,9-dichloro-2,4,8,10-tetrachloro-3,9-diphospho-spiro-3,9-dioxy-[5.5]undecane (SPDPC)].The method has a simple synthesis process, and the obtained chlorinated spirocyclic phosphate has high purity and a yield of up to 74%. At the same time, since phosphorus oxychloride and pentaerythritol are added in an amount of 2.1:1, the post-treatment of the reaction product is relatively convenient, and the problems of harm to the health of operators and the environment caused by excessive phosphorus oxychloride are reduced. Summary of the invention

[0004] The purpose of the present invention is to provide a simpler and more effective method for preparing chlorinated spirocyclic phosphate [3,9-dichloro-2,4,8,10-tetrachloro-3,9-diphosphaspiro-3,9-dioxo[5.5]undecane (SPDPC)].

[0005] The specific content is: a method for synthesizing chlorinated spirocyclic phosphate, characterized in that chlorinated spirocyclic phosphate [3,9-dichloro-2,4,8,10-tetrachloro-3,9-diphosphospiro-3,9-dioxo[5.5]undecane (SPDPC)] is obtained by using phosphorus oxychloride, pentaerythritol and a trace amount of organic solvent under the reaction conditions of 60 to 120 degrees Celsius and reacting for 12 to 24 hours by a partial heating reaction method.

[0006] The structure of the obtained chlorinated spirocyclic phosphate [3,9-dichloro-2,4,8,10-tetrachloro-3,9-diphospho-spiro-3,9-dioxo[5.5]undecane (SPDPC)] is as follows:

[0007]

[0008] The method comprises the following steps:

[0009] a) The preparation route of chlorinated spirocyclic phosphate [3,9-dichloro-2,4,8,10-tetrachloro-3,9-diphospho-spiro-3,9-dioxo[5.5]undecane (SPDPC)] is as follows:

[0010]

[0011] b) adding phosphorus oxychloride and pentaerythritol in an appropriate molar ratio into a reactor connected to a device for absorbing hydrogen chloride gas with an ice-water mixed solution, starting mechanical stirring to react at a relatively low temperature, and then continuing the reaction at a relatively high temperature for a period of time, at which time a large amount of white solid appears and stirring is relatively difficult;

[0012] c) adding an appropriate amount of organic solvent to dilute the mixture using a constant pressure dropping funnel, and reacting at this temperature for 4 to 8 hours under mechanical stirring;

[0013] d) Use a constant pressure dropping funnel to continue adding an appropriate amount for further dilution, and keep the reaction at this temperature for 4 to 8 hours under mechanical stirring until no gas is released;

[0014] e) The white solid obtained by cooling and filtration was washed three times with dichloromethane and anhydrous ether respectively, and dried under vacuum at 60° C. for 10 hours to obtain a white powdery solid.

[0015] The molar ratio of pentaerythritol to phosphorus oxychloride in step b) is 1:(2-2.1); the lower reaction temperature in step b) is 60°C-100°C for 1-4 hours; the higher reaction temperature in step a) is 80°C-110°C for 3-6 hours;

[0016] The organic solvent in step c) is 1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane, or dioxane, and the amount of the organic solvent added in step c) is 2% to 5% of the total mass of the reactants;

[0017] The organic solvent in step d) is one of 1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane and dioxane, and the amount of the organic solvent added in step d) is 3% to 6% of the total mass of the reactants.

[0018] Beneficial Effects

[0019] It can be seen from the above technical scheme and implementation method that the present invention synthesizes the chlorinated spirocyclic phosphate [3,9-dichloro-2,4,8,10-tetrachloro-3,9-diphosphospiro-3,9-dioxo[5.5]undecane (SPDPC)] by a one-step method at a relatively low temperature in the case of a trace amount of 1,1,2,2-tetrachloroethane as a solvent and a reaction amount of phosphorus oxychloride and pentaerythritol of 2.1:1. The method has the advantages of simple synthesis process, low reaction temperature, less phosphorus oxychloride used, less harm to operators and the environment caused by excessive phosphorus oxychloride, and is suitable for large-scale production. In addition, the synthesis process is a one-step method and is carried out continuously without the need to process intermediate products, thereby saving energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The chlorinated spirocyclic phosphate [3,9-dichloro-2,4,8,10-tetrachloro-3,9-diphospho-spiro-3,9-dioxo[5.5]undecane (SPDPC)] of the present invention 1 HNMR

[0021] Figure 2 The chlorinated spirocyclic phosphate [3,9-dichloro-2,4,8,10-tetrachloro-3,9-diphospho-spiro-3,9-dioxo[5.5]undecane (SPDPC)] of the present invention 31 PNMR

[0022] Figure 3The FT-IR of the chlorinated spirocyclic phosphate [3,9-dichloro-2,4,8,10-tetrachloro-3,9-diphospho-spiro-3,9-dioxo[5.5]undecane (SPDPC)] of the present invention is DETAILED DESCRIPTION

[0023] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0024] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0025] The chlorinated spirocyclic phosphate [3,9-dichloro-2,4,8,10-tetrachloro-3,9-diphosphospiro-3,9-dioxo[5.5]undecane (SPDPC)] of the present invention is prepared by reacting phosphorus oxychloride and pentaerythritol, and the preparation process is as follows: phosphorus oxychloride and pentaerythritol are added in a molar ratio of 2.1:1 into a reactor connected with an ice-water mixed solution absorbing hydrogen chloride gas device, mechanical stirring is turned on to react at 60°C to 100°C for 1 to 4 hours, then react at 80°C to 110°C for 3 to 6 hours, and then 1,1,2,2-tetrachloroethane (1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane, dioxane, etc.) in an amount of 2% to 5% of the total mass of the reactants is added through a constant pressure dropping funnel, and the mixture is kept warm at 80°C to 110°C for reaction for 4 to 8 hours. Then, 3% to 6% of the total mass of the reactants in 1,1,2,2-tetrachloroethane (1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane, dioxane, etc.) is added through a constant pressure dropping funnel, and the mixture is kept at 80°C to 110°C for 4 to 8 hours until no gas is released. The white solid obtained by cooling and filtration is washed three times with dichloromethane and anhydrous ether, and dried at 60°C in vacuum for 10 hours to obtain a white solid powder, which is the desired chlorinated spirocyclic phosphate [3,9-dichloro-2,4,8,10-tetrachloro-3,9-diphosphaspiro-3,9-dioxo[5.5]undecane (SPDPC)].

[0026] Example 1

[0027] 1.2mol phosphorus oxychloride, actual weight 183.99g, 0.57mol pentaerythritol, actual weight 77.61g, added to a 500ml three-necked flask, installed with a condenser tail gas collection device, etc., mechanically stirred, heated to 60℃ for 2 hours, slowly heated to 80℃, kept at this temperature for 3 hours, at this time there is a large amount of white solid, stirring is difficult, add 15ml1,1,2,2-tetrachloroethane with a constant pressure dropping funnel, keep at this temperature for 4 hours, at this time a large amount of white solid appears, basically stirring can not move, then add 25ml1,1,2,2-tetrachloroethane, at this time the solid part dissolves, keep at this temperature for 4 hours, until no gas is released. The white solid obtained by cooling and filtering is filtered, washed with dichloromethane and anhydrous ether, and dried at 60℃ in vacuum for 1 hour to obtain 99.8g white solid, yield: 59.2%.

[0028] Example 2

[0029] 1.2mol phosphorus oxychloride, actual weight 183.99g, 0.57mol pentaerythritol, actual weight 77.61g, added to a 500ml three-necked flask, installed with a condenser tail gas collection device, etc., mechanically stirred, heated to 80℃ for 3 hours, slowly heated to 100℃, kept at this temperature for 5 hours, at this time there is a large amount of white solid, stirring is difficult, add 25ml1,1,2,2-tetrachloroethane with a constant pressure dropping funnel, keep at this temperature for 6 hours, at this time a large amount of white solid appears, basically stirring can not move, then add 30ml1,1,2,2-tetrachloroethane, at this time the solid part dissolves, keep at this temperature for 6 hours, until no gas is released. The white solid obtained by cooling and filtering is filtered, washed with dichloromethane and anhydrous ether, and dried at 60℃ in vacuum for 1 hour to obtain 124.75g white solid, yield: 74%.

[0030] Example 3

[0031] 1.2mol phosphorus oxychloride, actual weight 183.99g, 0.57mol pentaerythritol, actual weight 77.61g, added to a 500ml three-necked flask, installed with a condenser tail gas collection device, etc., mechanically stirred, heated to 100℃ for 4 hours, slowly heated to 110℃, kept at this temperature for 6 hours, at this time there is a large amount of white solid, stirring is difficult, add 35ml1,1,2,2-tetrachloroethane with a constant pressure dropping funnel, keep at this temperature for 8 hours, at this time a large amount of white solid appears, basically stirring can not move, then add 45ml1,1,2,2-tetrachloroethane, at this time the solid part dissolves, keep at this temperature for 8 hours, until no gas is released. The white solid obtained by cooling and filtering is filtered, washed with dichloromethane and anhydrous ether, and dried at 60℃ in vacuum for 1 hour to obtain 106.34g white solid, yield: 62.9%.

[0032] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for synthesizing a chlorinated spirocyclic phosphate, characterized in that: Chlorinated spirocyclic phosphate [3,9-dichloro-2,4,8,10-tetrachloro-3,9-diphosphospiro-3,9-dioxo[5.5]undecane (SPDPC)] is obtained by using phosphorus oxychloride, pentaerythritol and a trace amount of organic solvent under the reaction conditions of 60 to 120 degrees Celsius and a partial heating reaction method for 12 to 24 hours.

2. The method for synthesizing a chlorinated spirocyclic phosphate according to claim 1, characterized in that: The structure of the chlorinated spirocyclic phosphate [3,9-dichloro-2,4,8,10-tetrachloro-3,9-diphospho-3,9-dioxo[5.5]undecane (SPDPC)] obtained by the preparation method according to claim 1 is as follows:

3. A method for synthesizing a chlorinated spirocyclic phosphate as claimed in claim 1, characterized in that The method comprises the following steps: a) The preparation route of chlorinated spirocyclic phosphate [3,9-dichloro-2,4,8,10-tetrachloro-3,9-diphospho-spiro-3,9-dioxo[5.5]undecane (SPDPC)] is as follows: b) adding phosphorus oxychloride and pentaerythritol in an appropriate molar ratio into a reactor connected to a device for absorbing hydrogen chloride gas with an ice-water mixed solution, starting mechanical stirring to react at a relatively low temperature, and then continuing the reaction at a relatively high temperature for a period of time, at which time a large amount of white solid appears and stirring is relatively difficult; c) adding an appropriate amount of organic solvent to dilute the mixture using a constant pressure dropping funnel, and reacting at this temperature for 4 to 8 hours under mechanical stirring; d) Use a constant pressure dropping funnel to continue adding an appropriate amount for further dilution, and keep the reaction at this temperature for 4 to 8 hours under mechanical stirring until no gas is released; e) The white solid obtained by cooling and filtration was washed three times with dichloromethane and anhydrous ether respectively, and dried under vacuum at 60° C. for 10 hours to obtain a white powdery solid.

4. The method for synthesizing a chlorinated spirocyclic phosphate according to claim 3, characterized in that: The molar ratio of pentaerythritol to phosphorus oxychloride in step b) is 1:(2-2.1); the lower reaction temperature in step b) is 60°C-100°C for reaction for 1-4 hours; the higher reaction temperature in step a) is 80°C-110°C for reaction for 3-6 hours.

5. The method for synthesizing a chlorinated spirocyclic phosphate according to claim 3, characterized in that: The organic solvent in step c) is one of 1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane and dioxane, and the amount of the organic solvent added in step c) is 2% to 5% of the total mass of the reactants.

6. The method for synthesizing a chlorinated spirocyclic phosphate according to claim 3, characterized in that: The organic solvent in step d) is one of 1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane and dioxane, and the amount of the organic solvent added in step d) is 3% to 6% of the total mass of the reactants.

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