Preparation method of chlorinated diphenyl phosphate
By using pyridine catalysts and phosphorus trichloride in the preparation of diphenyl phosphate chloride to form a complex, the reaction and distillation conditions are controlled, and the problems of low yield and high cost are solved, and the preparation effect of high yield and low cost is achieved.
Patent Information
- Application Number
- CN202510594408.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-09
- Publication Date
- 2025-08-15
AI Technical Summary
In the prior art, the preparation of diphenyl phosphate chloride has problems such as low yield, high cost and low product purity, which is mainly due to the improper treatment method of the catalyst, which leads to many by-products and difficult to separate.
Pyridine, substituted pyridine or its salt is used to form a stable complex with oxychloride, and the reaction temperature and distillation conditions are controlled so that the by-product generation is reduced. The catalyst is separated and can be reused below the main product distillation temperature.
The yield of diphenyl phosphate chloride is improved, production costs are reduced, and the reuse of catalysts and energy consumption are achieved.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of chemical industry, and particularly relates to a preparation method of diphenyl chlorinated phosphate. Background Art
[0002] Diphenyl phosphate (DPCP) is an important organophosphorus intermediate used not only in the synthesis of diphenyl phosphate azide but also as an intermediate in the synthesis of flame retardants, such as the bisphosphate flame retardants neopentyl glycol diphenyl phosphate (NDP), bisphenol A bis(diphenyl phosphate) (BDP), and N,N'-bis(diphenyl phosphate)piperazine. DPCP is also used as a highly efficient condensing agent in polycondensation reactions. Therefore, DPCP is an indispensable chemical raw material intermediate.
[0003] Currently, DPCP is typically prepared by partial esterification and distillation of phenol and phosphorus oxychloride in the presence of a Lewis acid catalyst, such as aluminum chloride or calcium chloride. This reaction produces some monoesterified products, monophenyl dichloride and triphenyl phosphate, resulting in low yields and high production costs. Furthermore, the presence of the catalyst during distillation can cause DPCP to decompose, reducing product purity and yield. Existing technologies differ primarily in the catalyst treatment methods, primarily in the following aspects: (1) removing the aluminum chloride catalyst from the system through two distillations increases energy consumption and costs; (2) Gao Cunsheng et al. deactivate the aluminum chloride catalyst by adding water to the reaction system. This technique is not only ineffective, but the addition of water also causes hydrolysis of the main product; (3) sodium carbonate is added to the reaction system in the hope that it will react with the calcium chloride catalyst to form calcium carbonate and sodium chloride as a precipitate. However, this technique suffers from the disadvantage that the added sodium carbonate is insoluble in the reaction system and therefore does not react with the catalyst to form a precipitate. Summary of the Invention
[0004] In view of this, the object of the present invention is to provide a method for preparing diphenyl chlorinated phosphate, which has the characteristics of high yield, safety, cleanliness and low cost.
[0005] In order to achieve the above object, the present invention provides the following technical solutions:
[0006] The present invention provides a method for preparing chlorinated diphenyl phosphate. The method uses a catalyst and a reactant, phosphorus oxychloride, to form a stable complex at a specific temperature, so that one chlorine atom in the phosphorus oxychloride is protected, thereby suppressing the formation of a by-product, triphenyl phosphate, during the reaction process, thereby increasing the yield of chlorinated diphenyl phosphate. Furthermore, the dissociation temperature of the complex and the boiling point of the catalyst are both lower than the distillation temperature of the main product. Therefore, the catalyst can be separated first during the distillation process without affecting the main product. The specific steps are as follows:
[0007] (1) adding phenol and phosphorus oxychloride as reactants to a reactor according to a mass ratio, and then adding a catalyst, heating and stirring the system to a certain temperature, continuing to heat the system under reflux until the temperature is fixed, reacting until no hydrogen chloride gas is generated, and detecting the content of diphenyl chlorinated phosphate and triphenyl phosphate;
[0008] (2) After the reaction is completed, the reactants are transferred to a distillation tower for vacuum distillation. The distillation temperature is controlled to separate the generated complex to obtain the catalyst and the by-product phenyl dichlorophosphate. The temperature is further increased and the distillation is continued to obtain diphenyl chlorinated phosphate;
[0009] The catalyst is pyridine, substituted pyridine, or a salt formed by pyridine and / or substituted pyridine.
[0010] Furthermore, in the step (1), the mass ratio of the reactants phenol to phosphorus oxychloride is 1:1 to 3:1, and the mass ratio of the catalyst to phosphorus oxychloride is 0.001:1 to 2.5:1.
[0011] Furthermore, the catalyst in step (1) is a substituted pyridine having the structural formula:
[0012]
[0013] Furthermore, the substitution position of the R group in the formula is not limited; the number of the R group substitutions is one or two;
[0014] The R group is:
[0015]
[0016] Furthermore, in the step (1), after the reactants are added, the system temperature is 50-100° C., the reaction temperature is 90-150° C., and the reaction time is 3-30 h.
[0017] Furthermore, in the step (2), the separation temperature of the phosphorus oxychloride complex is 140-170° C., and the temperature of distilling to obtain diphenyl chlorophosphate is 180-220° C.
[0018] Contains at least the following beneficial technical effects:
[0019] (1) The preferred catalyst of the present invention can form an effective complex with one of the chlorine atoms in the reactant phosphorus oxychloride, inhibiting the formation of triphenyl phosphate during the reaction, thereby increasing the yield of diphenyl chlorophosphate.
[0020] (2) The dissociation temperature of the complex is lower than the distillation temperature of triphenyl chlorophosphate, so the catalyst is collected in advance during distillation and can be reused, reducing energy consumption and costs. DETAILED DESCRIPTION
[0021] The present invention will be further described in detail below with reference to the examples. The following examples are merely illustrative and non-restrictive, and should not be used to limit the scope of protection of the present invention.
[0022] Unless otherwise specified, the reagents used in the present invention are all commercially available conventional reagents; the methods used in the present invention are all conventional methods used in the art unless otherwise specified.
[0023] Example 1:
[0024] Phenol and phosphorus oxychloride were added to a reactor in a mass ratio of 1:1, and a catalyst was added, with the catalyst amount accounting for 0.85% of the mass of phosphorus oxychloride. The system temperature was heated and stirred until it reached 90°C. The temperature was slowly raised to 140°C under reflux, and the temperature was maintained constant for 20 hours. The catalyst used was pyridine.
[0025] After the reaction was completed, the purity of diphenyl chlorophosphate was 77% and that of triphenyl phosphate was 3%. The reactants were transferred to a distillation tower and the vacuum was controlled to maintain a distillation temperature of 160°C. The resulting fractions were pyridine hydrochloride and phenyl dichlorophosphate. The temperature was raised to 180°C to obtain diphenyl chlorophosphate.
[0026] Example 2:
[0027] Phenol and phosphorus oxychloride were added to the reactor in a mass ratio of 1:1, and a catalyst was added. The amount of the catalyst was 0.85% of the mass of the phosphorus oxychloride. The system was heated and stirred until the temperature reached 90°C. The temperature was slowly raised to 150°C under reflux and the temperature was kept constant for 20 hours. The catalyst used was The R group is
[0028] After the reaction was completed, the purity of diphenyl chlorophosphate was 83% and that of triphenyl phosphate was 0.1%. The reactants were transferred to a distillation column and the vacuum was controlled to maintain a distillation temperature of 170°C. The resulting fractions were a fore-fraction containing dimethylaminopyridine hydrochloride and phenyl dichlorophosphate. The temperature was raised to 180°C to obtain diphenyl chlorophosphate.
[0029] Example 3:
[0030] Phenol and phosphorus oxychloride were added to the reactor in a mass ratio of 1:1, and a catalyst was added. The amount of the catalyst was 1.2% of the mass of the phosphorus oxychloride. The system temperature was heated and stirred until it reached 90°C. The temperature was slowly raised to 150°C under reflux and the temperature was kept constant for 20 hours. The catalyst used was The R group is - F .
[0031] After the reaction was completed, the purity of diphenyl chlorophosphate was 81% and that of triphenyl phosphate was 1.8%. The reactants were transferred to a distillation column and the vacuum was controlled to maintain a distillation temperature of 170°C. The resulting fractions were a fore-fraction of fluoropyridine hydrochloride and phenyl dichlorophosphate. The temperature was raised to 180°C to obtain diphenyl chlorophosphate.
[0032] Example 4:
[0033] Phenol and phosphorus oxychloride were added to the reactor in a mass ratio of 2:1, and a catalyst was added. The amount of the catalyst was 1.2% of the mass of the phosphorus oxychloride. The system temperature was heated and stirred until it reached 90°C. The temperature was slowly raised to 150°C under reflux and the temperature was kept constant for 20 hours. The catalyst used was The R group is - Cl .
[0034] After the reaction was completed, the purity of diphenyl chlorophosphate was 80% and that of triphenyl phosphate was 2%. The reactants were transferred to a distillation column and the vacuum was controlled to maintain a distillation temperature of 170°C. The resulting fractions were a fore-fraction of chloropyridine hydrochloride and phenyl dichlorophosphate. The temperature was raised to 180°C to obtain diphenyl chlorophosphate.
[0035] Although the present invention has been described in detail above, it is not limited thereto. Those skilled in the art can make modifications based on the principles of the present invention. Therefore, all modifications made according to the principles of the present invention should be understood to fall within the scope of protection of the present invention.
Claims
1. A method for preparing diphenyl chlorinated phosphate, characterized in that: The catalyst forms a stable complex with the reactant phosphorus oxychloride at a specific temperature, protecting one chlorine atom in the phosphorus oxychloride. This inhibits the formation of triphenyl phosphate, a by-product, during the reaction, thereby increasing the yield of diphenyl chlorinated phosphate. The dissociation temperature of the complex and the boiling point of the catalyst are both lower than the distillation temperature of the main product. During the distillation process, the catalyst can be separated without affecting the main product. The specific steps are as follows: (1) adding phenol and phosphorus oxychloride as reactants to a reactor according to a mass ratio, and then adding a catalyst, heating and stirring the system to a certain temperature, continuing to heat the system under reflux until the temperature is fixed, reacting until no hydrogen chloride gas is generated, and detecting the content of diphenyl chlorinated phosphate and triphenyl phosphate; (2) After the reaction is completed, the reactants are transferred to a distillation tower for vacuum distillation. The distillation temperature is controlled to separate the generated complex to obtain the catalyst and the by-product phenyl dichlorophosphate. The temperature is further increased and the distillation is continued to obtain diphenyl chlorinated phosphate; The catalyst is pyridine, substituted pyridine, or a salt formed by pyridine and / or substituted pyridine.
2. The preparation method according to claim 1, characterized in that In the step (1), the mass ratio of the reactants phenol to phosphorus oxychloride is 1:1 to 3:1, and the mass ratio of the catalyst to phosphorus oxychloride is 0.001:1 to 2.5:
1.
3. The preparation method according to claim 1, characterized in that The catalyst in step (1) is a substituted pyridine having the structural formula:
4. The preparation method according to claim 3, characterized in that The substitution position of the R group in the formula is not limited; the number of the R group substitutions is one or two; The R group is:
5. The preparation method according to claim 1, characterized in that After the reactants are added in step (1), the system temperature is 50-100° C., the reaction temperature is 90-150° C., and the reaction time is 3-30 hours.
6. The preparation method according to claim 1, characterized in that The separation temperature of the phosphorus oxychloride complex in the step (2) is 140-170° C., and the temperature of distilling to obtain diphenyl chlorophosphate is 180-220° C.