CN107383355A - A kind of continuous preparation method of PFPE - Google Patents

Abstract

The invention discloses a kind of method for the continuous preparation that PFPE is carried out using micro passage reaction, with CF₃CF₂CF₂O(CF₂CF(CF₃)O)_n‑2CF(CF₃) COOH is raw material, with F₂Reaction obtains corresponding PFPE.Method high conversion rate provided by the invention, the reaction time is short, reaction is safely controllable and suitable industrialization amplification.

Description

A kind of continuous preparation method of perfluoropolyether

technical field

The invention relates to a continuous preparation method of perfluoropolyether, in particular to a method for stabilizing the end group of perfluoropolyether carboxylic acid in a continuous flow microreactor.

Background technique

Perfluoropolyether (abbreviated as PFPE) is a high-molecular polymer. It is a colorless, odorless and transparent oily liquid at room temperature. It has the characteristics of heat resistance, oxidation resistance, radiation resistance, corrosion resistance, and non-combustibility. of lubricants. The acid fluoride end group and carboxylic acid end group in the molecular chain of perfluoropolyether are easy to decompose under high temperature conditions to generate volatile substances, causing a decrease in molecular weight, thereby limiting its application in high-tech fields.

For the improvement of the stability of the acid fluoride end group and the carboxylic acid end group in the perfluoropolyether molecular chain, the prior art has made the following efforts:

(1) U.S. Patent No. 355,100 discloses a method in which SbF5 is used as a fluorinating reagent to replace the acyl fluoride end groups in the molecular chain of perfluoropolyether with fluorine atoms to generate trifluoromethyl stable end groups. The product yield of this process is low, the reaction time is long, a large amount of antimony-containing compounds are generated, and post-treatment is difficult;

(2) Chinese patent CN201310635164 discloses a method of fluorinating and capping perfluoropolyetheryl fluoride groups with fluorine gas to obtain trifluoromethyl groups. This method needs to be under high temperature and high pressure, and the amount of fluorine gas needs to be 6 times that of the raw material. The reaction time is long and the safety risk is great.

Therefore, it is hopeful to further improve the stabilization method of perfluoropolyether end group.

Contents of the invention

The purpose of the present invention is to provide a continuous preparation method of perfluoropolyether, which has the characteristics of high conversion rate, short reaction time, safe and controllable reaction and is suitable for industrial scale-up.

The present invention provides following technical scheme:

A kind of continuous preparation method of perfluoropolyether, described method is carried out in microchannel reactor, comprises the following steps:

(1) Let the raw material 2 enter the preheating module (3), the preheating temperature is -20～200°C, the raw material 2 is CF ₃ CF ₂ CF ₂ O(CF ₂ CF(CF ₃ )O) _n-2 CF (CF ₃ )COOH, and n is an integer greater than or equal to 4;

(2) Make raw material 2 and raw material 1 after step (1) preheating enter microchannel reaction module (4), described raw material 1 is F ₂ , raw material 2 and raw material 1 are in described microchannel reaction module (4) Mixing and reacting in the middle, the molar ratio of the raw material 1 and the raw material 2 is 0.8～6.0:1, the flow rate of the raw material 2 is 1～100g/min, the reaction temperature is -20～200°C, and the reaction pressure is 0～0.5MPa;

(3) Separate and purify the product obtained at the outlet of the microchannel reaction module (9) in step (2) to obtain the corresponding perfluoropolyether.

In the continuous preparation method of perfluoropolyether provided by the present invention, each module of the microchannel reactor is assembled before preparing the perfluoropolyether to obtain the microchannel reactor. As an example, as shown in Figure 3, a preheating module 3, six microchannel reaction modules 4-9 and a quenching module 10 can be installed in series, wherein: 1 connected to the preheating module 3 is the liquid phase The pump is used as the feed port of the raw material 2; the 2 connected to the microchannel reaction module 4 is a gas mass flow meter, which is used as the feed port of the raw material 1. After the microchannel reactor is connected, heat transfer oil can be used for heat transfer. During the preparation of perfluoropolyether, microchannel reaction modules can be increased or decreased as required.

In the continuous preparation method of perfluoropolyether provided by the present invention, as a preferred mode, the microchannel reactor has a mass transfer coefficient of 1-30Ka and a heat exchange capacity of 1700KW/m ² ·K or more.

In the continuous preparation method of perfluoropolyether provided by the present invention, as a preferred mode, the microchannel reactor is Corning G2 microreactor, microwell array microchannel reactor, finned microchannel reactor, capillary microchannel reactor reactors or multi-stream microreactors.

In the continuous preparation method of perfluoropolyether provided by the present invention, the microchannel structure in the reaction module of the microchannel reactor includes a direct flow channel structure and an enhanced mixing channel structure. Preferably, the direct-flow channel structure is a tubular structure, and the enhanced mixing channel structure is a T-shaped structure, a spherical structure, a spherical structure with baffles, a drop-shaped structure or a heart-shaped structure, and the channel diameter is 0.5 mm to 10mm.

In the continuous preparation method of perfluoropolyether provided by the present invention, since F ₂ needs to be used, it is preferable that the material of the microchannel reaction module is selected from silicon carbide, HaC alloy or manganese alloy.

In the continuous preparation method of perfluoropolyether provided by the present invention, the raw material 2 used is CF ₃ CF ₂ CF ₂ O(CF ₂ CF(CF ₃ )O) _n-2 CF(CF ₃ )COOH, and n is greater than An integer equal to 4. As a preferred manner, the material 2 is CF ₃ CF ₂ CF ₂ O(CF ₂ CF(CF ₃ )O) _n-2 CF(CF ₃ )COOH, and n is an integer selected from 15-100. As a further preferred manner, the raw material 2 is CF ₃ CF ₂ CF ₂ O(CF ₂ CF(CF ₃ )O) _n-2 CF(CF ₃ )COOH, and n is an integer selected from 30-80.

In the continuous preparation method of perfluoropolyether provided by the present invention, before the raw material 2 enters the preheating module 3, it needs to be preheated, and the preheating temperature is -20-200°C. Preferably, the preheating temperature is 30-140°C.

In the continuous preparation method of perfluoropolyether provided by the present invention, the raw material 1 used is F ₂ . As a preferred manner, the raw material ₁ is a mixed gas of F2 and at least one selected from nitrogen, helium and hydrogen fluoride. When the raw material ₁ is a mixed gas of F2 and at least one selected from nitrogen, helium and hydrogen fluoride gas, preferably, the molar concentration of fluorine in the mixed gas is 5-95%, more preferably , the molar concentration of fluorine in the mixed gas is 10-40%, and more preferably, the molar concentration of fluorine in the mixed gas is 20-30%.

In the continuous preparation method of perfluoropolyether provided by the present invention, the molar ratio of raw material 1 and raw material 2 is sufficient to make the reaction proceed smoothly. As a preferred manner, the molar ratio of the raw material 1 to the raw material 2 is 2.0-3.0:1.

In the continuous preparation method of perfluoropolyether provided by the present invention, the flow rate of raw material 2 is sufficient to make the reaction proceed smoothly. As a preferred manner, the flow rate of the raw material 2 is 10-50 g/min.

In the continuous preparation method of perfluoropolyether provided by the present invention, the reaction temperature in step (2) is -20-200°C. As a preferred manner, the reaction temperature is -5-50°C.

In the continuous preparation method of perfluoropolyether provided by the present invention, the reaction pressure in step (2) is 0-0.5 MPa. As a preferred manner, the reaction pressure is 0-0.3 MPa.

Description of drawings

Fig. 1 is a typical structural unit figure of the microchannel reactor module used by the present invention;

Fig. 2 is that the used of the present invention takes Corning microchannel reactor as an example block diagram;

Fig. 3 is that the used of the present invention takes Corning microchannel module as example microchannel reactor system device diagram, and in Fig. 3: 1 is liquid-phase pump (raw material 2 feed ports), 2 is gas mass flow meter (raw material 1 feed port), 3 is the preheating module, 4-9 is the microchannel reaction module, and 10 is the quenching module.

detailed description

The present invention will be further described below in conjunction with specific examples, but the present invention is not limited to these specific implementations. Those skilled in the art will realize that the present invention covers all alternatives, modifications and equivalents as may be included within the scope of the claims.

Example 1

Select 1 corning straight channel module (as a premixing preheating module), 6 corning "heart-shaped" microchannel reaction modules, 1 corning straight channel module (as a quenching module) and 8 heat transfer modules in Figure 2 , form the continuous flow microchannel reaction system according to the reaction process shown in accompanying drawing 3. Heat transfer oil is used as the reaction heat exchange medium. According to the forced heat transfer principle of the microchannel reactor, only two temperature measuring points are set at the reactor inlet and outlet. Before the reaction, the microchannel reaction system and connecting pipelines were dewatered and degreased respectively, and the system and connecting pipelines were passivated with fluorine gas using 5mol% fluorine-nitrogen mixed gas, and the air tightness inspection was carried out at 1.0MPa. Through the 1 liquid-phase pump (such as diaphragm metering pump) in accompanying drawing 3, feed material continuously and stably to microchannel reaction system. The fluorine-nitrogen mixed gas is continuously and quantitatively added to the microchannel reaction system through the 2 gas mass flowmeters in Fig. 3 .

Set the heat exchanger temperature to 70°C, that is, the reaction temperature, and set the reaction pressure to 0.1MPa. Raw material CF ₃ CF ₂ CF ₂ O(CF ₂ CF(CF ₃ )O) ₂ CF(CF ₃ )COOH (average weight-average molecular weight about 662), feed rate is 20g/min, 20mol% fluorine-nitrogen mixed gas feed The speed is 8.4g/min, and the molar ratio of fluorine gas to raw material is 1.5:1. The reaction raw materials enter the "heart-shaped" micro-channel reaction module 4 after passing through the micro-channel premixing and preheating module 3, and the mixed gas of fluorine and nitrogen directly enters the "heart-shaped" micro-channel reaction module 4 through the gas mass flow meter, In the channel reaction module 4-9, the mixed gas of fluorine and nitrogen reacts with the raw materials. After passing through the quenching module 10, the reaction crude product is separated by a gas-liquid separator to obtain a liquid phase product, and a perfluoropolyether de-end grouped product is obtained.

The obtained perfluoropolyether de-end group product was tested by infrared spectrum, showing that the characteristic peak of the carbonyl group of the carboxylic acid completely disappeared, indicating that the perfluoropolyether carboxylic acid was completely converted into the product CF ₃ CF ₂ CF ₂ O(CF ₂ CF(CF ₃ )O) ₂ CFCF ₃ .

Example 2

Use the same Corning microchannel reactor as in Example 1, and follow the same connection and control methods. In this example, the reaction conditions were changed.

Set the heat exchanger temperature to 70°C, that is, the reaction temperature, and set the reaction pressure to 0 MPa. Raw material CF ₃ CF ₂ CF ₂ O(CF ₂ CF(CF ₃ )O) ₅₂ CF(CF ₃ )COOH (average weight-average molecular weight about 8692), feed rate is 16g/min, 20mol% fluorine-nitrogen mixed gas feed The speed is 2.7g/min, and the molar ratio of fluorine gas to raw material is 8:1. The reaction raw materials enter the "heart-shaped" micro-channel reaction module 4 after passing through the micro-channel premixing and preheating module 3, and the mixed gas of fluorine and nitrogen directly enters the "heart-shaped" micro-channel reaction module 4 through the gas mass flow meter, In the channel reaction module 4-9, the mixed gas of fluorine and nitrogen reacts with the raw materials. After passing through the quenching module 10, the reaction crude product is separated by a gas-liquid separator to obtain a liquid phase product, and a perfluoropolyether product is obtained. The infrared spectrum shows that the characteristic peak of the carbonyl group of the carboxylic acid completely disappears, indicating that the perfluoropolyether carboxylic acid is completely converted into the product CF ₃ CF ₂ CF ₂ O(CF ₂ CF(CF ₃ )O) ₅₂ CFCF ₃ .

Example 3

Use the same Corning microchannel reactor as in Example 1, and follow the same connection and control methods. In this example, the reaction conditions were changed.

Set the heat exchanger temperature to 120°C, that is, the reaction temperature, and set the reaction pressure to 0 MPa. Raw material CF ₃ CF ₂ CF ₂ O(CF ₂ CF(CF ₃ )O) ₂₂ CF(CF ₃ )COOH (average weight-average molecular weight about 3982), feed rate is 17g/min, 20mol% fluorine-nitrogen mixed gas feed The speed is 1.7g/min, and the molar ratio of fluorine gas to raw material is 2.1:1. The reaction raw materials enter the "heart-shaped" micro-channel reaction module 4 after passing through the micro-channel premixing and preheating module 3, and the mixed gas of fluorine and nitrogen directly enters the "heart-shaped" micro-channel reaction module 4 through the gas mass flow meter, In the channel reaction module 4-9, the mixed gas of fluorine and nitrogen reacts with the raw materials. After passing through the quenching module 10, the reaction crude product is separated by a gas-liquid separator to obtain a liquid phase product, and a perfluoropolyether product is obtained. The infrared spectrum shows that the characteristic peak of the carbonyl group of the carboxylic acid completely disappears, indicating that the perfluoropolyether carboxylic acid is completely converted into the product CF ₃ CF ₂ CF ₂ O(CF ₂ CF(CF ₃ )O) ₂₂ CFCF ₃ .

Example 4

Use the same Corning microchannel reactor as in Example 1, and follow the same connection and control methods. In this example, the reaction conditions were changed.

Set the heat exchanger temperature to 130°C, that is, the reaction temperature, and set the reaction pressure to 0 MPa. Raw material CF ₃ CF ₂ CF ₂ O(CF ₂ CF(CF ₃ )O) ₄₆ CF(CF ₃ )COOH (average weight-average molecular weight about 7966), feed rate is 9.6g/min, 30mol% fluorine-nitrogen mixed gas The material speed is 0.43g/min, and the molar ratio of fluorine gas to raw material is 3.0:1. The reaction raw materials enter the "heart-shaped" micro-channel reaction module 4 after passing through the micro-channel premixing and preheating module 3, and the mixed gas of fluorine and nitrogen directly enters the "heart-shaped" micro-channel reaction module 4 through the gas mass flow meter, In the channel reaction module 4-9, the mixed gas of fluorine and nitrogen reacts with the raw materials. The reaction crude product is separated by a gas-liquid separator after being passed through the quenching module 10 to obtain a liquid phase product, and a perfluoropolyether product is obtained. The infrared spectrum shows that the characteristic peak of the carbonyl group of the carboxylic acid completely disappears, indicating that the perfluoropolyether carboxylic acid is completely converted into the product CF ₃ CF ₂ CF ₂ O(CF ₂ CF(CF ₃ )O) ₄₆ CFCF ₃ .

Example 5

Use the same Corning microchannel reactor as in Example 1, and follow the same connection and control methods. In this example, the reaction conditions were changed.

Set the heat exchanger temperature to 30°C, that is, the reaction temperature, and set the reaction pressure to 0.1 MPa. The raw material is CF ₃ CF ₂ CF ₂ O(CF ₂ CF(CF ₃ )O) ₅₈ CF(CF ₃ )COOH (average weight-average molecular weight about 9958), the feed rate is 13.2g/min, 20mol% fluorine-nitrogen mixed gas The material speed is 1.1g/min, and the molar ratio of fluorine gas to raw material is 4.3:1. The reaction raw materials enter the "heart-shaped" micro-channel reaction module 4 after passing through the micro-channel premixing and preheating module 3, and the mixed gas of fluorine and nitrogen directly enters the "heart-shaped" micro-channel reaction module 4 through the gas mass flow meter, In the channel reaction module 4-9, the mixed gas of fluorine and nitrogen reacts with the raw materials. After passing through the quenching module 10, the reaction crude product is separated by a gas-liquid separator to obtain a liquid phase product, and a perfluoropolyether product is obtained. The infrared spectrum shows that the characteristic peak of the carbonyl group of the carboxylic acid completely disappears, indicating that the carboxylic acid of the perfluoropolyether is completely converted into the product CF ₃ CF ₂ CF ₂ O(CF ₂ CF(CF ₃ )O) ₅₈ CFCF ₃ .

Example 6

Use the same Corning microchannel reactor as in Example 1, and follow the same connection and control methods. In this example, the reaction conditions were changed.

Set the heat exchanger temperature to 100°C, that is, the reaction temperature, and set the reaction pressure to 0.1 MPa. Raw material CF ₃ CF ₂ CF ₂ O(CF ₂ CF(CF ₃ )O) ₄₀ CF(CF ₃ )COOH (average weight-average molecular weight about 6970), feed rate is 9.16g/min, 30mol% fluorine nitrogen mixed gas The material speed is 0.66g/min, and the molar ratio of fluorine gas to raw material is 3.9:1. The reaction raw materials enter the "heart-shaped" micro-channel reaction module 4 after passing through the micro-channel premixing and preheating module 3, and the mixed gas of fluorine and nitrogen directly enters the "heart-shaped" micro-channel reaction module 4 through the gas mass flow meter, In the channel reaction module 4-9, the mixed gas of fluorine and nitrogen reacts with the raw materials. After passing through the quenching module 10, the reaction crude product is separated by a gas-liquid separator to obtain a liquid phase product, and a perfluoropolyether product is obtained. The infrared spectrum shows that the characteristic peak of the carbonyl group of the carboxylic acid completely disappears, indicating that the perfluoropolyether carboxylic acid is completely converted into the product CF ₃ CF ₂ CF ₂ O(CF ₂ CF(CF ₃ )O) ₄₀ CFCF ₃ .

Example 7

Use the same Corning microchannel reactor as in Example 1, and follow the same connection and control methods. In this example, the reaction conditions were changed.

Set the heat exchanger temperature to 120°C, that is, the reaction temperature, and set the reaction pressure to 0.1 MPa. Raw material CF ₃ CF ₂ CF ₂ O(CF ₂ CF(CF ₃ )O) ₂₈ CF(CF ₃ )COOH (average weight-average molecular weight about 4978), feed rate is 4.8g/min, 20mol% fluorine-nitrogen mixed gas The material speed is 0.55g/min, and the molar ratio of fluorine gas to raw material is 3.0:1. The reaction raw materials enter the "heart-shaped" micro-channel reaction module 4 after passing through the micro-channel premixing and preheating module 3, and the mixed gas of fluorine and nitrogen directly enters the "heart-shaped" micro-channel reaction module 4 through the gas mass flow meter, In the channel reaction module 4-9, the mixed gas of fluorine and nitrogen reacts with the raw materials. After passing through the quenching module 10, the reaction crude product is separated by a gas-liquid separator to obtain a liquid phase product, and a perfluoropolyether product is obtained. The infrared spectrum shows that the characteristic peak of the carbonyl group of the carboxylic acid completely disappears, indicating that the perfluoropolyether carboxylic acid is completely converted into the product CF ₃ CF ₂ CF ₂ O(CF ₂ CF(CF ₃ )O) ₂₈ CFCF ₃ .

Claims (10)

1. the continuous preparation method of a kind of PFPE, it is characterised in that methods described is carried out in micro passage reaction, including following step Suddenly：

(1) raw material 2 is made to enter warm-up block (3), preheating temperature is -20~200 DEG C, and the raw material 2 is CF₃CF₂CF₂O(CF₂CF(CF₃)O)_n-2CF(CF₃) COOH, and n is the integer more than or equal to 4；

(2) raw material 2 after step (1) preheats and raw material 1 is made to enter microchannel reaction module (4), the raw material 1 is F₂, raw material 2 and raw material 1 mix and react in the microchannel reaction module (4), mole of the raw material 1 and raw material 2 Match as 0.8~6.0:1, the flow of raw material 2 is 1~100g/min, and reaction temperature is -20~200 DEG C, reaction pressure is 0~ 0.5MPa；

(3) corresponding perfluor is obtained after the product separating-purifying for obtaining step (2) microchannel reaction module (9) exit to gather Ether.

2. according to the continuous preparation method of the PFPE described in claim 1, it is characterised in that in the step (1)：Raw material 2 is CF₃CF₂CF₂O(CF₂CF(CF₃)O)_n-2CF(CF₃) COOH, and n is selected from 15~100 integer；Preheating temperature is 30~140 DEG C.

3. according to the continuous preparation method of the PFPE described in claim 2, it is characterised in that the step (1)：Raw material 2 is CF₃CF₂CF₂O(CF₂CF(CF₃)O)_n-2CF(CF₃) COOH, and n is selected from 30~80 integer.

4. according to the continuous preparation method of the PFPE described in claim 1, it is characterised in that in the step (2)：The original The mol ratio of material 1 and raw material 2 is 2.0~3.0:1, the flow of raw material 2 is 10~50g/min, and reaction temperature is -5~50 DEG C, Reaction pressure is 0~0.3MPa.

5. according to the continuous preparation method of the PFPE described in claim 1, it is characterised in that in the step (2)：The raw material 1 is F₂With the gaseous mixture selected from least one of nitrogen, helium and hydrogen fluoride gas, the molar concentration of fluorine gas in the gaseous mixture For 5~95%.

6. according to the continuous preparation method of the PFPE described in claim 5, it is characterised in that fluorine gas is mole dense in the gaseous mixture Spend for 10~40%.

7. according to the continuous preparation method of the PFPE described in claim 6, it is characterised in that fluorine gas is mole dense in the gaseous mixture Spend for 20~30%.

8. according to the continuous preparation method of the PFPE described in claim 1, it is characterised in that：Microchannel plate described in step (2) Module is answered, its material is selected from carborundum, breathes out C alloy or manganese Nai Er alloys, the mass tranfer coefficient of the micro passage reaction is 1~30Ka, Exchange capability of heat is 1700KW/m²More than K.

9. according to the continuous preparation method of the PFPE described in claim 1, it is characterised in that：The reaction mould of the micro passage reaction MCA in block includes once-through type channel design and enhancing mixed type channel design, and the once-through type channel design is tubulose Structure, the enhancing mixed type channel design is T-type structure, spherical structure, spherical band baffle arrangement, drops structure or the heart Type structure, and channel diameter is 0.5mm~10mm.

10. according to the continuous preparation method of the PFPE described in claim 1, it is characterised in that：The micro passage reaction is healthy and free from worry G2 microreactors, microwell array decline channel reactor, finned micro passage reaction, capillary microchannels reactor or multiply Parallel type microreactor.