Device and process for multi-stage continuous production of 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene

Abstract

The invention relates to a device and a process for multi-stage continuous production of 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene, comprising a plurality of repeated reactors, decanters, circulating pumps and mixed acid cooler units; each group of unit devices consists of a reactor, a decanter, a circulating pump and a mixed acid cooler: an upper feed port of the reactor is respectively connected with an oil phase production port of a front unit decanter, and a lower feed port is connected with an outlet of a rear unit mixed acid cooler; an inlet of a rear unit mixed acid cooler is connected with an outlet of a rear circulating pump, and an inlet of the circulating pump is connected with an acid phase production port of a decanter; a discharge port of the reactor is connected with an inlet of a decanter; a raw material 2,5-dichloro-(1,1,2,3,3,3-hexafluoropropoxy)benzene and a mixed solution of concentrated sulfuric acid and nitric acid are subjected to multi-stage countercurrent, thereby avoiding a large amount of heat release process of a violent nitration reaction, the reaction temperature is stable and controllable, and the production efficiency is improved.

Description

Technical Field

[0001] The invention relates to a device and a process for multi-stage continuous production of 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene, belonging to the technical field of fine chemical synthesis. Background Art

[0002] Lufenuron is an insect chitin synthesis inhibitor announced by Novartis in 1997. It belongs to the benzoylurea insecticide. It is mainly used to control larvae of Lepidoptera such as cotton, corn, vegetables, and fruit trees; it can also be used as a hygienic drug; it can also be used to control pests of animals such as cattle. The agent kills pests by acting on insect larvae and preventing the molting process. It has excellent control effects on leaf-eating caterpillars such as fruit trees. It has a unique killing mechanism for thrips, rust mites, and whiteflies, and is suitable for controlling pests that are resistant to synthetic pyrethroids and organophosphorus pesticides. It is safe for crops and can be used for crops such as corn, vegetables, citrus, cotton, potatoes, grapes, and soybeans. It is suitable for integrated pest management. The agent will not cause piercing-sucking pests to become rampant again, and it has a mild effect on adult beneficial insects and predatory spiders.

[0003] 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene is an important intermediate in the synthesis of lufenuron and is synthesized through nitration reaction. Usually, 2,5-dichloro-(1,1,2,3,3,3-hexafluoropropoxy)benzene reacts with nitric acid under the condition of concentrated sulfuric acid as a catalyst to generate 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene and water.

[0004] The reaction equation is as follows:

[0005]

[0006] This reaction is a hazardous chemical process that is subject to key supervision. It is an exothermic process. The higher the temperature, the faster the nitration reaction is, and the more heat is released instantaneously, which can easily cause temperature runaway and explosion. The nitrating agent is highly corrosive and oxidizing, and can cause combustion or explosion when in contact with oils, fats, and organic compounds.

[0007] At present, intermittent stirred tank reactors are mostly used in industry for preparation, and the production process is as follows: concentrated sulfuric acid and concentrated nitric acid are prepared into mixed acid in proportion for standby use, the measured 2,5-dichloro-(1,1,2,3,3,3-hexafluoropropoxy)benzene is added into the reactor, the refrigerated brine is turned on to cool down, the temperature in the reactor is controlled at 20-25°C, the mixed acid is slowly added to 2,5-dichloro-(1,1,2,3,3,3-hexafluoropropoxy)benzene at a certain rate, the reaction temperature is controlled, and the addition is stopped when the temperature is too high. When the amount of the mixed acid is added to 10%, the addition is suspended, and sampling is performed to detect whether there is 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene in the oil phase to confirm whether the nitration reaction is proceeding normally, and then the addition is continued. The addition is completed in about 12-15 hours, and the mixture is kept warm and stirred for 2 hours. The above-mentioned intermittent production process has problems such as a large number of equipment sets, low degree of automation, high safety risks caused by frequent repeated start-up and shutdown processes, operations being greatly affected by human factors, unstable product quality, and large amounts of waste acid. Summary of the invention

[0008] In view of the problems existing in the intermittent production process, the present invention provides a multi-stage continuous production process and device for 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene. The multi-stage countercurrent continuous reaction is adopted to avoid the violent reaction and large amount of heat release in the initiation stage of the nitration reaction. The reaction temperature is stable and controllable, the possibility of causing accidents is reduced, and the operation is safe.

[0009] The technical solution of the present invention is as follows:

[0010] The invention discloses a device for producing 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene in a multi-stage continuous manner, characterized in that it comprises a plurality of repeated reactor, decanter, circulation pump and mixed acid cooler units; each group of unit devices consists of a reactor, a decanter, a circulation pump and a mixed acid cooler: the upper feed port of the reactor is respectively connected to the oil phase production port of the decanter of the front unit, and the lower feed port is connected to the outlet of the mixed acid cooler of the rear unit; the inlet of the mixed acid cooler of the rear unit is connected to the outlet of the rear circulation pump, and the inlet of the circulation pump is connected to the acid phase production port of the decanter; the discharge port of the reactor is connected to the inlet of the decanter; and a multi-stage countercurrent continuous reaction device is adopted.

[0011] The upper feed port of the reactor of the first group of unit devices is connected to the outlet of the storage container of 2,5-dichloro-(1,1,2,3,3,3-hexafluoropropoxy)benzene as the raw material feed port; the acid phase extraction outlet of the decanter is connected to the inlet of related equipment for waste acid treatment as the outlet of the waste acid.

[0012] The lower feed port of the last group of unit devices is connected to the outlet of the new acid configuration storage container as the mixed acid feed port, and the decanter oil phase production outlet is the product 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene.

[0013] The reactor is any reactor, preferably a microreactor.

[0014] The process of producing 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene by a multi-stage continuous device of the present invention is as follows after the starting unit, the repeating unit and the last group of unit processes:

[0015] Starting Unit:

[0016] 2,5-dichloro-(1,1,2,3,3,3-hexafluoropropoxy)benzene and mixed acid undergo nitration reaction in a primary reactor, and then the reaction product is sent to a primary decanter to separate the oil phase from the acid phase, and the collected acid phase is extracted and sent to post-treatment as waste acid; the separated oil phase is sent to the next reactor as a primary nitration reactant to continue the nitration reaction;

[0017] Repeating Unit:

[0018] The nitration reactants of the first group of units and the acid of the second group of units undergo nitration reaction in the reactor, and then the reaction products are sent to a decanter to separate the oil phase from the acid phase. The collected acid phase enters the first group of reactors through a circulation pump and a mixed acid cooler; the separated oil phase enters the lower reactor as the second group of nitration reactants to continue the nitration reaction;

[0019] The last set of units:

[0020] The last group of nitration reactants undergo nitration reaction with the newly configured acid in the final reactor, and then the reaction products are sent to a decanter to separate the oil phase and the acid phase. The collected acid phase enters the previous group of reactors through a circulation pump and a mixed acid cooler; the separated oil phase is the product 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene.

[0021] The newly configured acid is composed of nitric acid and sulfuric acid in a mass ratio of 1:(1-4); the temperature of the nitration reaction is 10-50° C., and the total reaction time is 4-8 hours.

[0022] The method for producing 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene by a multi-stage continuous device is characterized in that the number of repeated reaction units is determined according to the processing volume and conversion rate requirements.

[0023] The raw material 2,5-dichloro-(1,1,2,3,3,3-hexafluoropropoxy)benzene and the mixed solution of concentrated sulfuric acid and nitric acid of the present invention are subjected to multi-stage countercurrent flow, thereby avoiding the large amount of heat release process of the violent nitration reaction. Compared with the existing intermittent production process, the continuous multi-stage countercurrent production process of the present invention, the raw material 2,5-dichloro-(1,1,2,3,3,3-hexafluoropropoxy)benzene and the mixed solution of concentrated sulfuric acid and nitric acid are subjected to multi-stage countercurrent flow, thereby avoiding the large amount of heat release process of the violent nitration reaction, and the reaction temperature is stable and controllable, greatly reducing the possibility of causing accidents; the reaction time is shortened from about 17 hours of intermittent production to 4 to 8 hours, greatly improving the production efficiency. A new high-efficiency, safe, and low-cost continuous production process of 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene is provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the process flow for continuous production of 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene in the embodiment (can be repeated according to the requirements of processing volume and conversion rate).

[0025] Among them, R1-primary reactor, R2-N-stage reactor, R3-final reactor, D1-primary decanter, D2-N-stage decanter, D3-final decanter, P1-final circulation pump, P2-N-stage circulation pump, E1-final mixed acid cooler, E2-N-stage mixed acid cooler, 1-2,5-dichloro-(1,1,2,3,3,3-hexafluoropropoxy)benzene, 2-configured new mixed acid, 3-1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene, 4-produced waste acid, 5-primary reaction product, 6-primary decanter oil phase, 7-N-stage reaction product, 8-N-stage decanter oil phase, 9-final reaction product, 10-final decanter acid phase, 11-N-stage decanter acid phase. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with specific embodiments, wherein the methods are conventional methods unless otherwise specified, and the raw materials can be obtained from public commercial channels unless otherwise specified. In addition, in the description of the present invention, it should be understood that the orientations or positional relationships indicated by the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0027] In the following embodiments, R1-primary reactor, R2-N-stage reactor, R3-final reactor, D1-primary decanter, D2-N-stage decanter, D3-final decanter, P1-final circulation pump, P2-N-stage circulation pump, E1-final mixed acid cooler, E2-N-stage mixed acid cooler, 1-2,5-dichloro-(1,1,2,3,3,3-hexafluoropropoxy)benzene, 2-configured new mixed acid, 3-1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene, 4-extracted waste acid, 5-primary reaction product, 6-primary decanter oil phase, 7-N-stage reaction product, 8-N-stage decanter oil phase, 9-final reaction product, 10-final decanter acid phase, 11-N-stage decanter acid phase.

[0028] like Figure 1 As shown:

[0029] The reactor is used for nitration reaction; preferably, a microreactor is selected, the inner diameter of the channel is 15 mm, the shell side is a heat transfer oil heat medium, and a refrigerant countercurrent heat is used to ensure that the reaction temperature is stable within the range of 10 to 50° C. The refrigerant can be frozen brine; the microreactor 1 is provided with a feed port, a discharge port, a refrigerant inlet and a refrigerant outlet;

[0030] The decanter is used to separate the oil phase and the acid phase in the reaction product; the decanter is provided with an inlet, an oil phase extraction port and an acid phase extraction port;

[0031] The circulating pump is used to provide power for acid phase production;

[0032] The mixed acid cooler is used to cool the acid solution; the mixed acid cooler uses a refrigerant countercurrent to extract heat to ensure that the temperature of the mixed acid solution does not exceed 20°C, and the refrigerant can be refrigerated brine; the mixed acid cooler is provided with an inlet, an outlet, a refrigerant inlet and a refrigerant outlet.

[0033] 2,5-Dichloro-(1,1,2,3,3,3-hexafluoropropoxy)benzene (1) and mixed acid (11) are subjected to nitration reaction in a primary reactor (R1), and then the reaction product (5) is sent to a primary decanter (D1) for separation of oil phase and acid phase, and the collected acid phase (4) is taken out as waste acid for post-treatment. The separated oil phase (6) is sent to the next group of reactors (R2) as a primary nitration reactant to continue the nitration reaction.

[0034] The primary nitration reactant (5) and the acid (10) of the latter unit undergo nitration reaction in the reactor (R2), and then the reaction product (7) is sent to the decanter (D2) for separation of the oil phase and the acid phase, and the collected acid phase (11) enters the primary reactor (R1) through the circulation pump (P2) and the mixed acid cooler (E2).

[0035] The nitration reactant (8) and the newly prepared acid (2) undergo nitration reaction in the final reactor (R3), and then the reaction product (9) is sent to the final decanter (D3) for separation of the oil phase and the acid phase, and the collected acid phase (10) enters the N-stage reactor (R2) through the circulation pump (P1) and the mixed acid cooler (E1). The separated oil phase is the product 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene.

[0036] The fresh acid solution is composed of nitric acid and sulfuric acid in a mass ratio of 1: (1-4). The temperature of the nitration reaction is 10-50°C, and the reaction time is 4-8h.

[0037] N levels of repetition can be performed according to the processing volume and conversion rate requirements.

[0038] Example 1

[0039] Taking the production capacity of 80t / a 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene (3), annual operation time 7000h, N=3 as an example, the specific process flow is as follows:

[0040] 2,5-Dichloro-(1,1,2,3,3,3-hexafluoropropoxy)benzene enters the primary reactor (R1) with the primary acid at a flow rate of 10 kg / h for nitration reaction, and the reaction temperature is controlled at 25°C; then the reaction product is sent to the primary decanter (D1) for separation of the oil phase and the acid phase, and the collected acid phase is extracted at a flow rate of 6.75 kg / h and enters the post-treatment as waste acid.

[0041] The separated oil phase enters the secondary reactor (R2) as the primary nitration reactant and the final acid to continue the nitration reaction, and the reaction temperature is controlled at 25°C; then the reaction product is sent to the secondary decanter (D2) to separate the oil phase and the acid phase, and the separated acid phase enters the primary reactor (R1) through a circulation pump and a mixed acid cooler; the separated oil phase enters the final reactor (R3) as the secondary nitration reactant and the configured new mixed acid (2) enters the final reactor (R3) at a flow rate of 8.27 kg / h for nitration reaction, and the reaction temperature is controlled at 25°C.

[0042] The reaction product from the final reactor (R3) enters the final decanter (D3) for oleic acid stratification, and the separated acid phase enters the secondary reactor (R2) through a circulation pump and a mixed acid cooler, and the oil phase 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene (3) is extracted and stored as a product at a flow rate of 11.52 kg / h.

[0043] The reaction time in this embodiment is 4 hours, the purity of the product obtained is greater than 98.0%, and the yield is 97.5%.

[0044] Example 2

[0045] Based on Example 1, taking N=4 as an example, the specific process flow is as follows:

[0046] 2,5-Dichloro-(1,1,2,3,3,3-hexafluoropropoxy)benzene enters the primary reactor (R1) at a flow rate of 10 kg / h and the secondary acid for nitration reaction, and the reaction temperature is controlled at 25°C.

[0047] The reaction product was sent to a primary decanter (D1) to separate the oil phase from the acid phase. The collected acid phase was taken out at a flow rate of 6.75 kg / h and entered post-treatment as waste acid. The separated oil phase entered the secondary reactor as the primary nitration reactant and the primary acid to continue the nitration reaction. The reaction temperature was controlled at 25°C.

[0048] The reaction product is sent to a secondary decanter to separate the oil phase from the acid phase, and the separated acid phase enters the primary reactor (R1) through a circulation pump and a mixed acid cooler;

[0049] The separated oil phase enters the third-stage reactor as the secondary nitration reactant and the final acid enters the third-stage reactor for nitration reaction, and the reaction temperature is controlled at 25°C;

[0050] The reaction product is sent to a three-stage decanter to separate the oil phase from the acid phase, and the separated acid phase enters the secondary reactor through a circulation pump and a mixed acid cooler;

[0051] The separated oil phase enters the final reactor (R3) as the tertiary nitration reactant and the configured new mixed acid (2) at a flow rate of 8.27 kg / h to carry out nitration reaction, and the reaction temperature is controlled at 25°C.

[0052] The reaction product from the final reactor (R3) enters the decanter (D3) for oleic acid stratification, and the separated acid phase enters the tertiary reactor through a circulation pump and a mixed acid cooler, and the oil phase 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene (3) is extracted and stored as a product at a flow rate of 11.52 kg / h.

[0053] The reaction time in this embodiment is 6 hours, the purity of the product obtained is greater than 99%, and the yield is 98.7%.

Claims

1. A multi-stage continuous production process of 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene, characterized in that: The device comprises a plurality of repeated reactor, decanter, circulation pump and mixed acid cooler units; each unit device consists of a reactor, a decanter, a circulation pump and a mixed acid cooler: the upper feed port of the reactor is respectively connected to the oil phase extraction port of the decanter of the previous unit, and the lower feed port is connected to the outlet of the mixed acid cooler of the next unit; the inlet of the mixed acid cooler of the next unit is connected to the outlet of the subsequent circulation pump, and the inlet of the circulation pump is connected to the acid phase extraction port of the decanter; the discharge port of the reactor is connected to the inlet of the decanter; a multi-stage countercurrent continuous reaction device is adopted; The upper feed port of the reactor of the first group of unit devices is connected to the outlet of the storage container of 2,5-dichloro-(1,1,2,3,3,3-hexafluoropropoxy)benzene as the raw material feed port; the acid phase extraction outlet of the decanter is connected to the inlet of the relevant equipment for waste acid treatment as the outlet of the waste acid; The lower feed port of the last group of unit devices is connected to the outlet of the new acid configuration storage container as the mixed acid feed port, and the oil phase production outlet of the decanter is the product 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene; The newly configured acid is composed of nitric acid and sulfuric acid in a mass ratio of 1: (1-4); the temperature of the nitration reaction is 10-50°C, the total reaction time is 4-8 h, and the number of repetitions of the repeated reaction unit is determined according to the processing volume and conversion rate requirements; The process for producing 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene is as follows: Starting Unit: 2,5-dichloro-(1,1,2,3,3,3-hexafluoropropoxy)benzene and mixed acid undergo nitration reaction in a primary reactor, and then the reaction product is sent to a primary decanter to separate the oil phase from the acid phase, and the collected acid phase is extracted and sent to post-treatment as waste acid; the separated oil phase is sent to the next reactor as a primary nitration reactant to continue the nitration reaction; Repeating Unit: The nitration reactants of the first group of units and the acid of the second group of units undergo nitration reaction in the reactor, and then the reaction products are sent to a decanter to separate the oil phase from the acid phase. The collected acid phase enters the first group of reactors through a circulation pump and a mixed acid cooler; the separated oil phase enters the lower reactor as the second group of nitration reactants to continue the nitration reaction; The last set of units: The last group of nitration reactants undergo nitration reaction with the newly configured acid in the final reactor, and then the reaction products are sent to a decanter to separate the oil phase and the acid phase. The collected acid phase enters the previous group of reactors through a circulation pump and a mixed acid cooler; the separated oil phase is the product 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene.

2. The multi-stage continuous production process of 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene as claimed in claim 1, characterized in that: The reactor is a microreactor.

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