A continuous production device and a continuous preparation method of diaryl chlorophosphate

Abstract

The present invention belongs to the technical field of organic synthesis, and particularly relates to a continuous production device and a continuous preparation method of diaryl chlorophosphate. The device provided by the present invention includes two reaction systems. By setting the two reaction systems, the esterification reaction for synthesizing aryl dichlorophosphate and the esterification reaction for synthesizing diaryl chlorophosphate are carried out at different temperatures, which can accurately control the reaction conditions of different steps, thereby reducing the generation of triaryl phosphate by-products and improving the purity of diaryl chlorophosphate. At the same time, the device provided by the present invention includes a multi-stage series reaction unit, which can extend the residence time of the reaction materials in the reactor and ensure the conversion rate of the materials; during the synthesis process, the generated hydrogen chloride can be removed in time through a wiped film reactor, further promoting the reaction and improving the yield and purity of diaryl chlorophosphate.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic synthesis, and particularly relates to a continuous production device and a continuous preparation method of diaryl chlorophosphate. Background Art

[0002] Diaryl chlorophosphate has low volatility and good thermal stability, and is an intermediate for synthesizing flame retardants, having the structure shown in (I), wherein R 1 and R 2 are each independently an alkyl group having 1 to 5 carbon atoms, and R 3 is an alkyl group having 1 to 5 carbon atoms.

[0003]

[0004] Aromatic diphosphate is an intermediate for synthesizing diaryl chlorophosphate, having the structure shown in (II), wherein R 1 and R 2 are each independently an alkyl group having 1 to 5 carbon atoms, R 3 and R 4 are each independently an alkyl group having 1 to 5 carbon atoms, Y is -CH2-, -C(CH3)2-, -S-, -SO2-, -O-, -CO- or -N=N-, k is 0 or 1, and m is an integer from 0 to 4.

[0005]

[0006] Currently, diaryl chlorophosphate is mainly prepared by an intermittent synthesis method. For example, in Chinese Patent CN102985430A, phosphoryl chloride is added dropwise to a mixed solution of an aromatic monohydroxy compound, a solvent and a catalyst for intermittent reaction to synthesize diaryl chlorophosphate; the specific reaction process is as follows: phosphoryl chloride first reacts with the aromatic monohydroxy compound to form aryl dichlorophosphate, and the formed aryl dichlorophosphate continues to dehalogenate to form diaryl chlorophosphate. However, in the production process, diaryl chlorophosphate and the aromatic monohydroxy compound can further form a triaryl phosphate by-product. When phosphoryl chloride is in excess, the output ratio of aryl dichlorophosphate in the system will increase; when phosphoryl chloride is too little, the output ratio of the by-product triaryl phosphate in the system will increase. To increase the content of diaryl chlorophosphate in the product, this patent adds phosphoryl chloride in a ratio of 0.5 mole relative to 1 mole of the aromatic monohydroxy compound. Although the content of diaryl chlorophosphate in the product can be increased by controlling the addition amount of the reactants, the dropwise addition method of intermittent synthesis will cause the system ratio to be out of balance for a long time, and it is not possible to well ensure the purity of diaryl chlorophosphate. At the same time, in the intermittent synthesis mode, the HCl generated by dechlorination is difficult to be discharged in time, which slows down the reaction speed, reduces the production efficiency and increases the side reaction ratio, further reducing the purity of diaryl chlorophosphate. Summary of the Invention

[0007] In view of the above, the present invention provides a continuous production device and a continuous preparation method of diaryl chlorophosphate. Using the continuous production device provided by the present invention to prepare diaryl chlorophosphate can significantly improve the yield and purity of diaryl chlorophosphate.

[0008] To solve the above technical problems, the present invention provides a continuous production device, including a first reactant container 1;

[0009] A second reactant container 3;

[0010] A first reaction system 2 with inlets respectively connected to the outlets of the first reactant container 1 and the second reactant container 3; the first reaction system 2 includes a series of first reaction units, and any one of the first reaction units includes a mixer 5, a wiped film reactor 6-1, a condenser 10-1 and a gas-liquid separator 11-1 connected in sequence;

[0011] A second reaction system 4 with inlets respectively connected to the outlets of the first reactant container 1 and the first reaction system 2; the second reaction system 4 includes a series of second reaction units, and any one of the second reaction units includes a mixer 9-1, a wiped film reactor 7-1, a condenser 12-1 and a gas-liquid separator 13-1 connected in sequence; a heater 14 with an inlet connected to the outlet of the mixer 9-1 is further included in the first-stage second reaction unit of the second reaction system 4;

[0012] A tail gas absorption unit 15 communicated with the gas outlets of the first reaction system 2 and the second reaction system 4;

[0013] And a product collection unit 16 communicated with the liquid outlet of the second reaction system 4.

[0014] Preferably, the number of stages of the first reaction unit is 2 to 15; the number of stages of the second reaction unit is 2 to 20.

[0015] Preferably, the liquid outlet of the gas-liquid separator 11-1 in the first reaction system 2 is connected to the inlet of the wiped film reactor 6-1;

[0016] The liquid outlet of the gas-liquid separator 13-1 in the second reaction system 4 is connected to the inlet of the wiped film reactor 7-1.

[0017] The present invention also provides a method for preparing diaryl chlorophosphate using the device described in the above technical solution, including the following steps:

[0018] Mix the aromatic monohydroxy compound and the Lewis acid catalyst in the first reactant container 1 to obtain a premixed solution; the aromatic monohydroxy compound has the structure shown in Formula III:

[0019]

[0020] Wherein, R 1 , R 2 and R 3 are independently -H or an alkyl group with 1 to 5 carbon atoms;

[0021] Transport part of the premixed solution and phosphoryl chloride in the second reactant container 3 to the first reaction system 2. After mixing in the mixer 5, carry out the first esterification reaction in the wiped film reactor 6-1 to obtain aryl dichlorophosphate; the hydrogen chloride gas generated in the first esterification reaction is removed through the condenser 10-1 and the gas-liquid separator 11-1;

[0022] Transport the aryl dichlorophosphate and the remaining part of the premixed solution to the second reaction system 4. After mixing in the mixer 9-1, carry out the second esterification reaction in the wiped film reactor 7-1 to obtain diaryl chlorophosphate; the hydrogen chloride gas generated in the second esterification reaction is removed through the condenser 12-1 and the gas-liquid separator 13-1.

[0023] Preferably, the molar ratio of the aromatic monohydroxy compound to the Lewis acid catalyst is 40 to 1500:1;

[0024] The molar ratio of the aromatic monohydroxy compound to phosphoryl chloride in the part of the premixed solution is 1 to 1.5:1.

[0025] Preferably, the premixed solution is divided into multiple strands and enters the first reaction system 2 through one or more first reaction units in the first reaction system 2;

[0026] The remaining part of the premixed solution is divided into multiple strands and enters the second reaction system 4 through one or more second reaction units in the second reaction system 4.

[0027] Preferably, the temperature of the first esterification reaction is 80 to 150 °C.

[0028] Preferably, the temperature of the second esterification reaction is 100 to 200 °C.

[0029] Preferably, when mixing the aromatic monohydroxy compound and the Lewis acid catalyst in the first reactant container 1, it further includes: adding an organic solvent to the first reactant container 1;

[0030] The organic solvent includes one or more of toluene, xylene, mesitylene, chlorobenzene, and dichlorobenzene.

[0031] Preferably, the Lewis acid catalyst includes one or more of aluminum chloride, magnesium chloride, titanium tetrachloride, antimony pentachloride, zinc chloride, and tin chloride.

[0032] The present invention provides a continuous production device, which includes a first reactant container 1; a second reactant container 3; a first reaction system 2 with inlets respectively connected to the outlets of the first reactant container 1 and the second reactant container 3; the first reaction system 2 includes a series of first reaction units, and any one of the first reaction units includes a mixer 5, a wiped film reactor 6-1, a condenser 10-1, and a gas-liquid separator 11-1 connected in sequence; a second reaction system 4 with inlets respectively connected to the outlets of the first reactant container 1 and the first reaction system 2; the second reaction system 4 includes a series of second reaction units, and any one of the second reaction units includes a mixer 9-1, a wiped film reactor 7-1, a condenser 12-1, and a gas-liquid separator 13-1 connected in sequence; a heater 14 with an inlet connected to the outlet of the mixer 9-1 is further included in the first-stage second reaction unit of the second reaction system 4; a tail gas absorption unit 15 communicated with the gas outlets of the first reaction system 2 and the second reaction system 4; and a product collection unit 16 communicated with the liquid outlet of the second reaction system 4. The device provided by the present invention includes two-stage reaction systems. By setting up two-stage reaction systems and carrying out the first esterification reaction and the second esterification reaction at different temperatures, the reaction conditions of different steps can be precisely controlled, thereby reducing the generation of triaryl phosphate by-products and improving the purity of diaryl chlorophosphate. At the same time, the device provided by the present invention includes a series of multi-stage reaction units, which can extend the residence time of the reaction materials in the reactor and ensure the conversion rate of the materials; during the synthesis process, the generated hydrogen chloride can be removed through the gas-liquid separator, further promoting the reaction and improving the yield and purity of diaryl chlorophosphate. Description of the Drawings

[0033] Figure 1 It is a structural schematic diagram of the continuous production device, where 1 is the first reactant container, 1-1 is the first inlet, 1-2 is the second inlet, 1-3 is the heating system, 1-4 is the first delivery pump, 1-5 is the stirring device, 2 is the first reaction system, 5 is the mixer in the first reaction system, 6-1 is the wiped film reactor in the first reaction system, 10-1 is the condenser in the first reaction system, 11-1 is the gas-liquid separator in the first reaction system, 3 is the second reactant container, 3-1 is the feed inlet, 3-2 is the second delivery pump, 4 is the second reaction system, 9-1 is the mixer in the second reaction system, 7-1 is the wiped film reactor in the second reaction system, 12-1 is the condenser in the second reaction system, 13-1 is the gas-liquid separator in the second reaction system, 14 is the heater, 15 is the tail gas absorption unit, and 16 is the product collection unit;

[0034] Figure 2 It is a structural schematic diagram of a continuous production device where the first reaction system is a second-level first reaction unit and the second reaction system is a third-level second reaction unit. Among them, 1 is the first reactant container, 1-1 is the first inlet, 1-2 is the second inlet, 1-3 is the heating system, 1-4 is the first transfer pump, 1-5 is the stirring device, 5 is the mixer in the first-level first reaction unit, 6-1 is the wiped film reactor in the first-level first reaction unit, 10-1 is the condenser in the first-level first reaction unit, 11-1 is the gas-liquid separator in the first-level first reaction unit, 8 is the mixer in the second-level first reaction unit, 6-2 is the wiped film reactor in the second-level first reaction unit, 10-2 is the condenser in the second-level first reaction unit, 11-2 is the gas-liquid separator in the second-level first reaction unit, 3 is the second reactant container, 3-1 is the feed inlet, 3-2 is the second transfer pump, 9-1 is the mixer in the first-level second reaction unit, 7-1 is the wiped film reactor in the first-level second reaction unit, 12-1 is the condenser in the first-level second reaction unit, 13-1 is the gas-liquid separator in the first-level second reaction unit, 14 is the heater, 9-2 is the mixer in the second-level second reaction unit, 7-2 is the wiped film reactor in the second-level second reaction unit, 12-2 is the condenser in the second-level second reaction unit, 13-2 is the gas-liquid separator in the second-level second reaction unit, 9-3 is the mixer in the third-level second reaction unit, 7-3 is the wiped film reactor in the third-level second reaction unit, 12-3 is the condenser in the third-level second reaction unit, 13-3 is the gas-liquid separator in the third-level second reaction unit, 15 is the tail gas absorption unit, and 16 is the product collection unit. Detailed implementation mode

[0035] The present invention provides a continuous production device, including the first reactant container 1. In the present invention, a heating system 1-3 is preferably provided on the outer wall surface of the first reactant container 1. In the present invention, the heating system 1-3 is preferably steam heating, and the present invention preferably uses the heating system 1-3 to heat the materials in the first reactant container 1 to ensure the temperature required for the subsequent chemical reaction in the first reaction system 2.

[0036] As an embodiment of the present invention, a first inlet 1-1 and a second inlet 1-2 are provided at the top of the first reactant container 1. In the present invention, the aromatic monohydroxy compound and the Lewis acid catalyst are introduced into the first reactant container 1 through the first inlet 1-1; the organic solvent is introduced into the first reactant container 1 through the second inlet 1-2. As an embodiment of the present invention, a stirring device 1-5 is provided in the first reactant container; the stirring device 1-5 can uniformly mix the reaction materials. As an embodiment of the present invention, the outlet of the first reactant container 1 is connected to a first transfer pump 1-4.

[0037] The continuous production device provided by the present invention includes a second reactant container 3. As an embodiment of the present invention, a feed inlet 3-1 is provided at the top of the second reactant container 3, and the outlet of the second reactant container 3 is connected to a second delivery pump 3-2.

[0038] The continuous production device provided by the present invention includes a first reaction system 2 whose inlets are respectively connected to the outlets of a first reactant container 1 and a second reactant container 3; the first reaction system 2 includes a series of first reaction units, and any one of the first reaction units includes a mixer 5, a wiped film reactor 6-1, a condenser 10-1, and a gas-liquid separator 11-1 connected in sequence. As an embodiment of the present invention, the number of stages of the first reaction unit is preferably 2 to 15 stages, more preferably 2 to 8 stages, and even more preferably 2 to 5 stages. The present invention provides a series of multiple first reaction units to ensure sufficient residence time to complete the reaction and improve the yield of the product. As an embodiment of the present invention, the liquid outlet of the gas-liquid separator 11-1 in the first reaction system 2 is connected to the inlet of the wiped film reactor 6-1; the liquid separated in the gas-liquid separator is returned to the wiped film reactor 6-1 to continue the first esterification reaction.

[0039] In the present invention, the outlet of the upper-stage first reaction unit is communicated with the inlet of the lower-stage first reaction unit. As an embodiment of the present invention, the reaction materials in the first reactant container 1 are divided into multiple streams and enter different first reaction units for the first esterification reaction; the gas generated during the reaction is condensed by the condenser 10-1 to separate hydrogen chloride, and the separated hydrogen chloride is removed by the gas-liquid separator 11-1; removing hydrogen chloride during the reaction is beneficial to the forward progress of the reaction.

[0040] In the present invention, the reaction materials in the first reactant container 1 and the second reactant container 3 are mixed in the mixer 5 of each stage of the first reaction unit.

[0041] In the present invention, a chemical reaction is carried out in the wiped film reactor 6-1 of each stage of the first reaction unit, which increases the contact probability of the reaction materials and can timely remove the generated gas, facilitating the progress of the reaction. As an embodiment of the present invention, a heat preservation system is provided on the outer wall of the wiped film reactor, and the heat preservation system is a steam heat preservation system. The present invention uses the heat preservation system to ensure the required reaction temperature in the wiped film reactor.

[0042] The continuous production device provided by the present invention includes a second reaction system 4 whose inlets are respectively connected to the outlet of the first reactant container 1 and the outlet of the first reaction system 2; the second reaction system 4 includes a series-connected second reaction unit, and any one of the second reaction units includes a mixer 9-1, a wiped film reactor 7-1, a condenser 12-1, and a gas-liquid separator 13-1 connected in sequence. As an embodiment of the present invention, the first-stage second reaction unit in the second reaction system 4 further includes a heater 14 whose inlet is connected to the outlet of the mixer 9-1. The present invention heats the material entering the second reaction system 4 through the heater 14 to ensure the temperature required for the chemical reaction in the second reaction system. As an embodiment of the present invention, the liquid outlet of the gas-liquid separator 13-1 in the second reaction system 4 is connected to the inlet of the wiped film reactor 7-1; the liquid separated in the gas-liquid separator 13-1 is returned to the wiped film reactor 7-1 to continue the second esterification reaction.

[0043] As an embodiment of the present invention, the number of stages of the second reaction unit is preferably 2 to 20 stages, more preferably 2 to 15 stages, and even more preferably 2 to 8 stages. The present invention provides a multi-stage series-connected second reaction unit to ensure sufficient residence time to complete the reaction and improve the product yield.

[0044] In the present invention, the outlet of the upper-stage second reaction unit is communicated with the inlet of the lower-stage second reaction unit. As an embodiment of the present invention, the reaction materials in the first reactant container 1 are divided into multiple streams and enter different second reaction units for the second esterification reaction; the gas generated during the reaction is condensed by the condenser to separate hydrogen chloride, and the separated hydrogen chloride is removed by the gas-liquid separator; removing hydrogen chloride during the reaction is beneficial to the forward progress of the reaction.

[0045] The continuous production device provided by the present invention includes a tail gas absorption unit 15 communicated with the gas outlet of the first reaction system 2 and the gas outlet of the second reaction system 4. In the present invention, the function of the tail gas absorption unit 15 is to absorb the hydrogen chloride separated by the gas-liquid separator.

[0046] The continuous production device provided by the present invention includes a product collection unit 16 communicated with the liquid outlet of the second reaction system 4. The present invention preferably collects and stores the product prepared by using the continuous production device by the product collection unit 16.

[0047] The present invention also provides a method for preparing diaryl chlorophosphate by using the device described in the above technical solution, including the following steps:

[0048] Mix an aromatic monohydroxy compound and a Lewis acid catalyst in the first reactant container 1 to obtain a premixed solution; the aromatic monohydroxy compound has the structure shown in Formula III:

[0049]

[0050] Among them, R 1 、R 2 and R 3 are independently -H or an alkyl group with 1 to 5 carbon atoms;

[0051] Part of the premixed liquid and phosphoryl chloride in the second reactant container 3 are transported to the first reaction system 2, mixed by the mixer 5, and then undergo the first esterification reaction in the wiped film reactor 6-1 to obtain aryl dichlorophosphate; the hydrogen chloride gas generated in the first esterification reaction is removed by the condenser 10-1 and the gas-liquid separator 11-1;

[0052] The aryl dichlorophosphate and the remaining premixed liquid are transported to the second reaction system 4, mixed by the mixer 9-1, and then undergo the second esterification reaction in the wiped film reactor 7-1 to obtain diaryl chlorophosphate; the hydrogen chloride gas generated in the second esterification reaction is removed by the condenser 12-1 and the gas-liquid separator 13-1.

[0053] In the present invention, the aromatic monohydroxy compound and the Lewis acid catalyst are mixed in the first reactant container 1 to obtain a premixed liquid. In the present invention, the aromatic monohydroxy compound has the structure shown in Formula III:

[0054]

[0055] Among them, R 1 、R 2 and R 3 are independently -H or an alkyl group with 1 to 5 carbon atoms, preferably independently an alkyl group with 2 to 4 carbon atoms; in the present invention, the alkyl group preferably includes methyl, ethyl, propyl, butyl or pentyl, more preferably methyl or ethyl. In the present invention, the aromatic monohydroxy compound is preferably 2,6-dimethylphenol.

[0056] In the present invention, the Lewis acid catalyst preferably includes one or more of aluminum chloride, magnesium chloride, titanium tetrachloride, antimony pentachloride, zinc chloride and tin chloride, more preferably aluminum chloride or magnesium chloride. In the present invention, when the Lewis acid catalyst includes two or more of the above specific substances, the present invention has no special requirements for the ratio of the specific substances, and any ratio can be adopted.

[0057] In the present invention, the molar ratio of the aromatic monohydroxy compound to the Lewis acid catalyst is preferably 40 to 1500:1, more preferably 50 to 300:1.

[0058] In the present invention, the aromatic monohydroxy compound and the Lewis acid catalyst are preferably introduced into the first reactant container through the first inlet 1-1.

[0059] In the present invention, when the aromatic monohydroxy compound and the Lewis acid catalyst are mixed in the first reactant container 1, the aromatic monohydroxy compound is preferably a molten liquid. When the aromatic monohydroxy compound is in such a state, the present invention preferably adds an organic solvent to the first reactant container 1. In the present invention, the organic solvent preferably includes one or more of toluene, xylene, mesitylene, chlorobenzene and dichlorobenzene, and more preferably toluene or dichlorobenzene. In the present invention, when there are two or more of the above specific substances as the organic solvent, there is no special requirement for the ratio of the specific substances, and any ratio can be adopted.

[0060] In the present invention, the mass ratio of the aromatic monohydroxy compound to the organic solvent is preferably 1 to 20:1, and more preferably 5 to 15:1.

[0061] The present invention preferably feeds the organic solvent into the first reactant container through the second inlet 1-2.

[0062] The present invention preferably uses the stirring device 1-5 to uniformly mix the aromatic monohydroxy compound, the Lewis acid catalyst and the organic solvent; the present invention preferably uses the heating system 1-3 to heat the premixed liquid.

[0063] After obtaining the premixed liquid, the present invention transports a part of the premixed liquid and phosphoryl chloride in the second reactant container 3 to the first reaction system 2. After mixing through the mixer 5, the first esterification reaction is carried out in the wiped film reactor 6-1 to obtain aryl dichlorophosphate; the hydrogen chloride gas generated by the first esterification reaction is removed through the condenser 10-1 and the gas-liquid separator 11-1. The present invention preferably uses the first transfer pump 1-4 to transport a part of the premixed liquid and the second transfer pump 3-2 to transport phosphoryl chloride. In the present invention, the molar ratio of the aromatic monohydroxy compound to phosphoryl chloride in the part of the premixed liquid is preferably 1 to 1.5:1, and more preferably 1 to 1.2:1.

[0064] Because at the reaction temperature of the first esterification reaction, only aryl dichlorophosphate can be generated, feeding more aromatic monohydroxy compounds is of little significance and will increase the amount of aromatic monohydroxy compounds carried out by HCl gas; the present invention limits the molar ratio of the aromatic monohydroxy compound to phosphoryl chloride in the part of the premixed liquid within the above range.

[0065] In the present invention, the premixed liquid is divided into multiple strands and enters the first reaction system 2 through one or more first reaction units in the first reaction system 2. The present invention preferably divides a part of the premixed liquid into multiple strands and transports them to the first reaction system 2 for the first esterification reaction in different first reaction units; the number of the multiple strands is less than or equal to the number of stages of the first reaction unit.

[0066] In the present invention, the temperature of the first esterification reaction is preferably 80 to 150 °C, more preferably 100 to 130 °C. The present invention preferably heats the premixed solution to ensure the reaction temperature of the first esterification reaction. In the present invention, the pressure of the first esterification reaction is preferably -30 to +20 kPaG, more preferably -30 to 0 kPaG.

[0067] After obtaining the aryl dichlorophosphate, the present invention transports the aryl dichlorophosphate and the remaining premixed solution to the second reaction system 4. After mixing in the mixer 9-1, the second esterification reaction is carried out in the wiped film reactor 7-1 to obtain diaryl chlorophosphate; the hydrogen chloride gas generated in the second esterification reaction is removed by the condenser 12-1 and the gas-liquid separator 13-1.

[0068] The present invention preferably divides the remaining part of the premixed solution into multiple streams and enters the second reaction system 4 through one or more stages of second reaction units in the second reaction system 4. The present invention preferably divides the remaining part of the premixed solution into multiple streams and transports them to the second reaction system 4 for the second esterification reaction in different second reaction units; the number of the multiple streams is less than or equal to the number of stages of the second reaction units. The present invention divides the remaining part of the premixed solution into multiple streams for transportation in order to gradually promote the conversion of phosphoryl chloride and aryl dichlorophosphate into diaryl chlorophosphate, and keep the amounts of phosphoryl chloride and aryl dichlorophosphate in the system dominant compared with the aromatic monohydroxy compound, so as to avoid the formation of the impurity triaryl phosphate.

[0069] In the present invention, the temperature of the second esterification reaction is preferably 100 to 200 °C, more preferably 130 to 180 °C. The present invention preferably uses the heater 14 to heat the mixed solution of the aryl dichlorophosphate and the remaining part of the premixed solution to ensure the reaction temperature of the second esterification reaction.

[0070] In the present invention, the pressure of the second esterification reaction is preferably -30 to +20 kPaG, more preferably -30 to 0 kPaG.

[0071] In the present invention, the total amount of phosphoryl chloride and aryl dichlorophosphate in the last-stage second reaction unit entering the second reaction system 4 is in excess compared with the remaining aromatic monohydroxy compound; the excess molar amount is preferably 0.5 to 10%, more preferably 1 to 6%. In the present invention, the aryl dichlorophosphate has the structure shown in Formula IV:

[0072]

[0073] Wherein, R 1 , R 2 and R 3Independently, it is -H or an alkyl group with 1 to 5 carbon atoms, preferably an alkyl group with 2 to 4 carbon atoms; in the present invention, the alkyl group preferably includes methyl, ethyl, propyl, butyl or pentyl, more preferably methyl or ethyl.

[0074] In the present invention, the triaryl phosphate has the structure shown in Formula V:

[0075]

[0076] Wherein, R 1 , R 2 and R 3 Independently, it is -H or an alkyl group with 1 to 5 carbon atoms, preferably an alkyl group with 2 to 4 carbon atoms; in the present invention, the alkyl group preferably includes methyl, ethyl, propyl, butyl or pentyl, more preferably methyl or ethyl.

[0077] In the present invention, both phosphoryl chloride and aryl dichlorophosphate can react with aromatic monohydroxy compounds to synthesize the main product diaryl chlorophosphate, while triaryl phosphate cannot be converted into the main product diaryl chlorophosphate. The last-stage reactor needs to adjust the proportion of the supplementary feed of aromatic monohydroxy compounds according to the excess of phosphoryl chloride and aryl dichlorophosphate relative to aromatic monohydroxy compounds in the discharge from the previous stage, so as to convert the residual phosphoryl chloride and aryl dichlorophosphate into the main product diaryl chlorophosphate as much as possible, while avoiding the formation of the impurity triaryl phosphate.

[0078] The present invention precisely controls the temperature of the second esterification reaction and adjusts the ratio of the supplementary feed of aromatic monohydroxy compounds to the residual phosphoryl chloride and aryl dichlorophosphate in the system according to the conversion situation, promoting the reaction of phosphoryl chloride and diaryl chlorophosphate with aromatic monohydroxy compounds to generate diaryl chlorophosphate to the greatest extent, and inhibiting the formation of the impurity triaryl phosphate, thereby improving the yield and purity of diaryl chlorophosphate.

[0079] In the present invention, the first reaction system 2 and the second reaction system 4 are composed of a multi-stage series of wiped-film reactors. The hydrogen chloride gas generated by the reaction is discharged from the upper part of each wiped-film reactor, and the synthesis liquid flows out from the bottom of each wiped-film reactor and enters the next series reactor until it flows out from the last-stage wiped-film reactor of the second reaction system 4 to obtain diaryl chlorophosphate.

[0080] In the present invention, the gas discharged from the upper part of each wiped-film reactor is condensed by a condenser to recover the phosphoryl chloride and aromatic monohydroxy compounds carried out by the gas, and is returned to the inlet end of the corresponding wiped-film reactor to re-enter the reaction system.

[0081] The present invention preferably adds an organic solvent to the condenser during the condensation process to wash the gas and the condenser, and the washing liquid returns to the inlet end of the corresponding wiped film reactor together with the washed and condensed phosphoryl chloride and aromatic monohydroxy compound and re-enters the reaction system.

[0082] The continuous preparation of diaryl chlorophosphate by using the device provided by the present invention has the following beneficial effects:

[0083] 1) By continuously synthesizing diaryl chlorophosphate, the production efficiency is greatly improved. The synthesis process, which used to take more than 20 hours in a batch reactor, is shortened to within a few minutes, greatly improving the production efficiency of the device and saving a large amount of investment.

[0084] 2) In each stage of the two-stage series reactor of the present invention, a wiped film reactor is used, and the reaction liquid flows from top to bottom by gravity, which can very well control backmixing and make the reaction complete as soon as possible; the reaction liquid is in a film state, and under the combined action of a relatively high reaction temperature, a slightly negative pressure and the reactor scraper, the generated hydrogen chloride can quickly escape from the reaction liquid, and the flow direction of the liquid film layer is opposite to the discharge direction of the hydrogen chloride gas. The closer the material is to the end point, the lower the concentration of hydrogen chloride in the gas-liquid two-phase, which maximally avoids the influence of hydrogen chloride on the reaction progress, is beneficial to promoting the forward reaction and shortening the production time.

[0085] 3) According to the reaction mechanism, the reaction of aryl dichlorophosphate is easier to proceed than that of diaryl chlorophosphate. The continuous reactor adopts a two-stage series gradient heating form in combination with the reaction mechanism. By first generating aryl dichlorophosphate at a lower temperature in the first-stage reactor, and then adding aromatic monohydroxy compounds step by step or selectively adding appropriate stages in the second-stage reactor, the aromatic monohydroxy compound reacts with aryl dichlorophosphate at a higher temperature to generate diaryl chlorophosphate, avoiding problems such as easy material flushing due to rapid heating and increased side reactions due to slow heating in a batch reaction.

[0086] 4) The present invention does not require a large vacuum system, nor does it need to introduce dry air or nitrogen to assist in the discharge of HCl gas, reducing the waste gas emissions. The reaction can be well completed under slightly negative pressure, normal pressure or slightly positive pressure, achieving good energy-saving and environmental protection effects.

[0087] 5) In the continuous production of the present invention, the process parameters are very easy to achieve stable control. By controlling the excess of phosphoryl chloride in the early stage of the reaction, it is very convenient to flexibly adjust the addition amount of aromatic monohydroxy compounds at the end stage of the second stage according to the actual situation, realizing the precise synthesis of diaryl chlorophosphate with a high yield and maximally inhibiting the presence of by-products aryl dichlorophosphate and triaryl phosphate in the product liquid.

[0088] 6) The production process of the present invention is continuous, with high equipment utilization rate, large production capacity, easy to achieve automated operation, stable process parameters, low difficulty in reactor scaling-up, large operation flexibility, and good guarantee of product yield and quality.

[0089] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0090] Example 1

[0091] 2,6-Dimethylphenol and magnesium chloride are introduced into the first reactant container 1 through the first inlet 1-1 according to a molar ratio of 150:1, and xylene is introduced into the second reactant container 3 through the second inlet 1-2. The mass ratio of xylene to 2,6-dimethylphenol is 1:15; the mixture is stirred evenly by the stirring device 1-5, and the mixed solution is heated to 90 °C by the steam heating system 1-3 to obtain a premixed solution.

[0092] The first reaction system 2 is a first reaction unit in series of three stages. Phosphoryl chloride is transported to the first-stage first reaction unit in the first reaction system 2 by the second delivery pump 3-2, and the premixed solution is respectively transported to the three-stage first reaction unit in the first reaction system 2 by the first delivery pump 1-4; the molar ratio of phosphoryl chloride to 2,6-dimethylphenol is 1:1.2; after the premixed solution and phosphoryl chloride are mixed by the mixer 5, they enter the scraping film reactor of the first-stage first reaction unit and carry out the first esterification reaction under the conditions of a pressure of -3 kPaG and a temperature of 115 °C; the generated gas is condensed by the condenser 10-1 and the hydrogen chloride is removed by the gas-liquid separator 11-1; the liquid generated in the first-stage first reaction unit and the premixed solution enter the subsequent two-stage first reaction units to obtain aryl dichlorophosphate; the flow rate ratio of the premixed solution in the first-stage first reaction unit, the premixed solution in the second-stage first reaction unit, and the premixed solution in the third-stage first reaction unit is 0.5:0.4:0.1.

[0093] The second reaction system is a 6-stage series-connected second reaction unit. After the aryl dichlorophosphate and the premixed solution are mixed by mixer 9-1, they are heated to 140°C by heater 14 and enter the scraping film reactor of the first-stage second reaction unit. The second esterification reaction is carried out under the conditions of a pressure of -3 kPaG and a temperature of 165°C; the generated gas is condensed by condenser 12-1 and then hydrogen chloride is removed by gas-liquid separator 13-1; the liquid generated in the first-stage second reaction unit and the premixed solution enter the second-stage second reaction unit, and the above steps are repeated to carry out the second esterification reaction in the 6-stage second reaction unit respectively, and the diaryl chlorophosphate is obtained and collected and stored in product collection unit 16; the flow rate ratio of the premixed solution in the first-stage second reaction unit, the premixed solution in the second-stage second reaction unit, the premixed solution in the third-stage second reaction unit, the premixed solution in the fourth-stage second reaction unit, the premixed solution in the fifth-stage second reaction unit and the premixed solution in the sixth-stage second reaction unit is 0.3:0.2:0.2:0.2:0.07:0.03;

[0094] The HCl gas discharged from the gas-phase outlet at the upper part of each reactor enters the tail gas absorption unit 15; the outlet temperature of the condenser is controlled at 55°C, and the liquid trapped by the gas-liquid separator returns to the corresponding scraping film reactor inlet and returns to the reaction system.

[0095] Example 2

[0096] 2,6-Dimethylphenol and magnesium chloride are introduced into the first reactant container 1 from the first inlet 1-1 according to a molar ratio of 100:1, and xylene is introduced into the second reactant container 3 from the second inlet 1-2. The mass ratio of xylene to 2,6-dimethylphenol is 1:15; the mixture is stirred evenly by stirring device 1-5, and the mixed solution is heated to 100°C by steam heating system 1-3 to obtain a premixed solution;

[0097] The first reaction system 2 is a first reaction unit with 4 - stage series connection. The phosphoryl chloride is transported to the first - stage first reaction unit in the first reaction system 2 by the second transfer pump 3 - 2, and the premixed solution is respectively transported to the 4 - stage first reaction units in the first reaction system 2 by the first transfer pump 1 - 4; the molar ratio of phosphoryl chloride to 2,6 - dimethylphenol is 1:1.3; the premixed solution and phosphoryl chloride enter the scraper - film reactor of the first - stage first reaction unit after being mixed by the mixer 5 and carry out the first esterification reaction under the conditions of a pressure of - 2 kPaG and a temperature of 120 °C; the generated gas is condensed by the condenser 10 - 1 and then the hydrogen chloride is removed by the gas - liquid separator 11 - 1; the liquid generated in the first - stage first reaction unit and the premixed solution enter the second - stage second reaction unit, and the above steps are repeated to carry out reactions in the 4 - stage first reaction units respectively to obtain aryl dichlorophosphate; the flow rate ratio of the premixed solution in the first - stage first reaction unit, the premixed solution in the second - stage first reaction unit, the premixed solution in the third - stage first reaction unit, and the premixed solution in the fourth - stage first reaction unit is 0.4:0.3:0.2:0.1.

[0098] The second reaction system is a second reaction unit with 7 - stage series connection. The aryl dichlorophosphate and the premixed solution are mixed by the mixer 9 - 1 and then heated to 150 °C by the heater 14 and enter the scraper - film reactor of the first - stage second reaction unit to carry out the second esterification reaction under the conditions of a pressure of - 2 kPaG and a temperature of 175 °C; the generated gas is condensed by the condenser 12 - 1 and then the hydrogen chloride is removed by the gas - liquid separator 13 - 1; the liquid generated in the first - stage second reaction unit and the premixed solution enter the second - stage second reaction unit, and the above steps are repeated to carry out the second esterification reaction in the 7 - stage second reaction units respectively to obtain diaryl chlorophosphate which is collected and stored in the product collection unit 16; the flow rate ratio of the premixed solution in the first - stage second reaction unit, the premixed solution in the second - stage second reaction unit, the premixed solution in the third - stage second reaction unit, the premixed solution in the fourth - stage second reaction unit, the premixed solution in the fifth - stage second reaction unit, the premixed solution in the sixth - stage second reaction unit, and the premixed solution in the seventh - stage second reaction unit is 0.25:0.2:0.15:0.15:0.13:0.1:0.02;

[0099] The HCl gas discharged from the gas - phase outlet at the upper part of each reactor enters the tail - gas absorption unit 15; the temperature at the outlet of the condenser is controlled at 55 °C, and the liquid captured by the gas - liquid separator returns to the inlet of the corresponding scraper - film reactor and back to the reaction system.

[0100] Example 3

[0101] 2,6-dimethylphenol and magnesium chloride are introduced into the first reactant container 1 through the first inlet 1-1 at a molar ratio of 300:1, and xylene is introduced into the second reactant container 3 through the second inlet 1-2. The mass ratio of xylene to 2,6-dimethylphenol is 1:12; they are stirred evenly by the stirring device 1-5 and heated to 120 °C by the steam heating system 1-3 to obtain a premixed solution.

[0102] The first reaction system 2 is a 4-stage series-connected first reaction unit. Phosphoryl chloride is transported to the first-stage first reaction unit in the first reaction system 2 by the second delivery pump 3-2, and the premixed solution is transported to the 4-stage first reaction units in the first reaction system 2 by the first delivery pump 1-4 respectively; the molar ratio of phosphoryl chloride to 2,6-dimethylphenol is 1:1.2; after being mixed by the mixer 5, the premixed solution and phosphoryl chloride enter the scraping film reactor of the first-stage first reaction unit and carry out the first esterification reaction under the conditions of a pressure of -9 kPaG and a temperature of 125 °C; the generated gas is condensed by the condenser 10-1 and then hydrogen chloride is removed by the gas-liquid separator 11-1; the liquid generated in the first-stage first reaction unit and the premixed solution enter the second-stage second reaction unit, and the above steps are repeated to carry out the first esterification reaction in the 4-stage first reaction units respectively to obtain aryl dichlorophosphate; the flow rate ratio of the premixed solution in the first-stage first reaction unit, the premixed solution in the second-stage first reaction unit, the premixed solution in the third-stage first reaction unit, and the premixed solution in the fourth-stage first reaction unit is 0.4:0.3:0.2:0.1.

[0103] The second reaction system is a 5-stage series-connected second reaction unit. After the aryl dichlorophosphate and the premixed solution are mixed by the mixer 9-1 and heated to 140 °C by the heater 14, they enter the scraping film reactor of the first-stage second reaction unit and carry out the second esterification reaction under the conditions of a pressure of -9 kPaG and a temperature of 150 °C; the generated gas is condensed by the condenser 12-1 and then hydrogen chloride is removed by the gas-liquid separator 13-1; the liquid generated in the first-stage second reaction unit and the premixed solution enter the second-stage second reaction unit, and the above steps are repeated to carry out the second esterification reaction in the 5-stage second reaction units respectively to obtain diaryl chlorophosphate which is collected and stored in the product collection unit 16; the flow rate ratio of the premixed solution in the first-stage second reaction unit, the premixed solution in the second-stage second reaction unit, the premixed solution in the third-stage second reaction unit, the premixed solution in the fourth-stage second reaction unit, and the premixed solution in the fifth-stage second reaction unit is 0.3:0.2:0.2:0.2:0.08:0.02;

[0104] The HCl gas discharged from the gas phase outlets at the upper parts of each reactor enters the tail gas absorption unit 15; the temperature at the outlet of the condenser is controlled at 55 °C, and the liquid captured by the gas-liquid separator returns to the inlet of the corresponding scraping film reactor and returns to the reaction system.

[0105] The obtained product was analyzed by nuclear magnetic resonance and liquid chromatography, and the conversion rate of 2,6-dimethylphenol, the yield of diaryl chlorophosphate, and the formation ratios of diaryl chlorophosphate to aryl dichlorophosphate and triaryl phosphate were calculated. The results are listed in Table 1.

[0106] Table 1 Conversion rate of 2,6-dimethylphenol and yield of diaryl chlorophosphate in Examples 1-3

[0107]

[0108]

[0109] As can be seen from Table 1, the diaryl chlorophosphate continuously prepared by using the device provided by the present invention has a high yield and purity.

[0110] Although the above embodiments have described the present invention in detail, they are only a part of the embodiments of the present invention, rather than all embodiments. People can also obtain other embodiments based on these embodiments without creative efforts, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A continuous preparation method of diaryl chlorophosphate, characterized in that, It includes the following steps: Mix an aromatic monohydroxy compound and a Lewis acid catalyst in a first reactant container (1) to obtain a premixed solution; the aromatic monohydroxy compound has the structure shown in Formula III: Wherein, R 1 , R 2 and R 3 are independently -H or an alkyl group having 1 to 5 carbon atoms; Transfer a part of the premixed solution and phosphoryl chloride in a second reactant container (3) to a first reaction system (2), mix them through a mixer (5), and then carry out a first esterification reaction in a wiped film reactor (6-1) to obtain an aryl dichlorophosphate; the hydrogen chloride gas generated in the first esterification reaction is removed through a condenser (10-1) and a gas-liquid separator (11-1); Transfer the aryl dichlorophosphate and the remaining part of the premixed solution to a second reaction system (4), mix them through a mixer (9-1), and then carry out a second esterification reaction in a wiped film reactor (7-1) to obtain a diaryl chlorophosphate; the hydrogen chloride gas generated in the second esterification reaction is removed through a condenser (12-1) and a gas-liquid separator (13-1).

2. The continuous preparation method of the diaryl chlorophosphate according to claim 1, characterized in that, The molar ratio of the aromatic monohydroxy compound to the Lewis acid catalyst is 40 to 1500:1; The molar ratio of the aromatic monohydroxy compound to phosphoryl chloride in the part of the premixed solution is 1 to 1.5:

1.

3. The continuous preparation method of diaryl chlorophosphate according to claim 1, characterized in that, The premixed solution is divided into multiple strands and enters the first reaction system (2) through one or more first reaction units in the first reaction system (2); The remaining part of the premixed solution is divided into multiple strands and enters the second reaction system (4) through one or more second reaction units in the second reaction system (4).

4. The continuous preparation method of diaryl chlorophosphate according to any one of claims 1 to 3, characterized in that, The temperature of the first esterification reaction is 80 to 150 °C.

5. The continuous preparation method of diaryl chlorophosphate according to any one of claims 1 to 3, characterized in that, The temperature of the second esterification reaction is 100 to 200 °C.

6. The continuous preparation method of the diaryl chlorophosphate according to claim 1, characterized in that, When mixing the aromatic monohydroxy compound and the Lewis acid catalyst in the first reactant container (1), it also includes: adding an organic solvent to the first reactant container (1); The organic solvent includes one or more of toluene, xylene, mesitylene, chlorobenzene, and dichlorobenzene.

7. The continuous preparation method of the diaryl chlorophosphate according to claim 1, characterized in that, The Lewis acid catalyst includes one or more of aluminum chloride, magnesium chloride, titanium tetrachloride, antimony pentachloride, zinc chloride, and tin chloride.

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