Preparation method of methyl perfluoroisobutyl ether

Abstract

The invention discloses a preparation method of methyl perfluoroisobutyl ether, which comprises the following steps: (1) gasifying octafluoroisobutylene methanol absorption liquid in a closed gas cabinet, then introducing the gasified octafluoroisobutylene methanol absorption liquid and chlorine into a chlorination coil reactor, and carrying out chlorination reaction to obtain heptafluorodichloroisobutyl methyl ether; and (2) introducing the heptafluorodichloroisobutyl methyl ether obtained in the step (1) and anhydrous hydrogen fluoride into a fluorination coil reactor loaded with a fluorination catalyst, and carrying out fluorination reaction to obtain the methyl perfluoroisobutyl ether. The methyl perfluoroisobutyl ether is prepared from the methanol absorption liquid of octafluoroisobutene, environmental pollution in the production process is reduced, resource utilization of waste is achieved, raw materials are easy to obtain, the preparation process is simple, the requirement for equipment is low, reaction conditions are mild, and the method is suitable for large-scale production and has a wide application prospect. The method is a green, environment-friendly, zero-emission and sustainable synthesis method capable of turning waste into wealth.

Description

TECHNICAL FIELD

[0001] The present application relates to the fluorinated chemical technology field, and in particular to a preparation method of methyl perfluoroisobutyl ether. BACKGROUND

[0002] Methyl perfluoroisobutyl ether is a colorless, odorless, non-toxic, non-corrosive, non-flammable liquid. It has good lubricity and solubility, and is considered to be very suitable for being used as a solvent for oily formulations. As a precision cleaning agent, methyl perfluoroisobutyl ether is applied to cleaning of printed circuit boards, metal and its parts, liquid crystal displays, precision electronic devices, optical components, aerospace equipment devices, medical device parts, plastic parts, etc., and can effectively remove grease, wax, rosin flux, fingerprints, sweat stains, particles, etc. Since the ODP value of methyl perfluoroisobutyl ether is zero and the GWP value is 320, it is an ideal alternative to ozone-depleting substances solvents such as CFC-113, trichloroethane, carbon tetrachloride, etc. Therefore, the market demand for methyl perfluoroisobutyl ether is great, and it has broad development prospects.

[0003] Octafluoroisobutylene is a toxic by-product obtained in the production of tetrafluoroethylene and hexafluoropropylene. In order to overcome the toxicity of octafluoroisobutylene, octafluoroisobutylene is usually treated by absorption with methanol to generate slightly less toxic heptafluoroisobutene methyl ether, and then incinerated in a incinerator, which not only increases the environmental pressure, but also wastes fluorine resources. Currently, there is a method for preparing methyl ether from heptafluoroisobutene to prepare hexafluoroacetone, but this method has the disadvantages of high equipment investment, high operation requirement, and low yield, and has not been applied on a large scale in industry.

[0004] Currently, the synthetic route for preparing methyl perfluoroisobutyl ether includes the following steps: carbon tetrachloride and pentachloropropene are reacted in the presence of a catalyst to generate nonachlorobutane; nonachlorobutane is dehydrochlorinated in the presence of a catalyst to generate perchlorobutene; perchlorobutene is catalytically fluorinated with anhydrous hydrogen fluoride to generate hexafluorodichlorobutene; hexafluorodichlorobutene is reacted with methanol to generate hexafluoro-monochloro-isopropenyl methyl ether; and hexafluoro-monochloro-isopropenyl methyl ether is catalytically synthesized into methyl perfluoroisobutyl ether in the presence of a catalyst. In addition, there are methods such as addition of halogenated alkenes, fluorochloroalkanes, fluorination of halogenated hydrocarbons, substitution of fluorinated acid esters and fluorinated ketones, bioelectrolysis of fluorohydrocarbons, and catalytic dehydrogenation of fluorohydrocarbons. However, these methods are limited in large-scale production due to the difficulty in obtaining raw materials, complex process, and high technical difficulty, and low yield. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a method for preparing methyl perfluoroisobutyl ether from methanol absorption liquid of octafluoroisobutylene. The raw materials of the present application are easy to obtain, the preparation process is simple, and the present application is suitable for large-scale production.

[0006] To solve the above technical problems, the application discloses a preparation method of methyl perfluoroisobutyl ether, which comprises the following steps:

[0007] (1) vaporizing octafluoroisobutene methanol absorbing solution in a closed gas cabinet, and then introducing the solution into a chlorination coil reactor together with chlorine to perform a chlorination reaction, so as to obtain heptafluorodichloroisobutyl methyl ether;

[0008] (2) introducing the heptafluorodichloroisobutyl methyl ether obtained in the step (1) into a fluorination coil reactor loaded with a fluorination catalyst together with anhydrous hydrogen fluoride to perform a fluorination reaction, so as to obtain methyl perfluoroisobutyl ether.

[0009] Further, the diameter of the coil of the chlorination coil reactor in the step (1) is 3 cm, and the length is 64 m.

[0010] Further, the temperature of the chlorination reaction in the step (1) is 300-350 DEG C.

[0011] Further, the molar feeding ratio of the octafluoroisobutene to the chlorine is 1:1-2.

[0012] Further, the diameter of the coil of the fluorination coil reactor in the step (2) is 1.5 cm, and the length is 36 m, so that the diameter is reduced, and the residence time of the reactants in the coil reactor can be increased in a limited space.

[0013] Further, the temperature of the fluorination reaction in the step (2) is 300-350 DEG C.

[0014] Further, the molar feeding ratio of the octafluoroisobutene to the hydrogen fluoride is 1:1-3.

[0015] Further, the fluorination catalyst in the step (2) is made of antimony chloride and a metal sulfate promoter.

[0016] Further, the mass ratio of the antimony chloride to the promoter is 1:2-5.

[0017] Further, the preparation method of the fluorination catalyst is as follows:

[0018] putting the metal sulfate and the antimony chloride into a coil reactor, introducing excess hydrogen fluoride into the reactor at a temperature of 100-150 DEG C to prepare the fluorination catalyst; the metal sulfate is one or more of NaAl (SO4) 2, KAl (SO4) 2, NaCr (SO4) 2, KCr (SO4) 2, NaFe (SO4) 2, KFe (SO4) 2, NaCr (SO4) 2 and KCr (SO4) 2.

[0019] The application has the following beneficial effects:

[0020] (1) The application utilizes the methanol absorption liquid of octafluoroisobutene to prepare methyl perfluoroisobutyl ether, avoids environmental pollution in the production process, realizes the resource utilization of waste, and is a synthesis method of turning waste into treasure, green environmental protection, zero emission and sustainable development.

[0021] (2) The application has the advantages of easy raw materials, simple preparation process, low equipment requirement, mild reaction condition, safe and easy operation, low production cost, and can be applied to the production of fluorine chemical products. DETAILED DESCRIPTION

[0022] The application will be further explained in combination with examples. The following examples are only used to illustrate the application, but not to limit the scope of the application.

[0023] I. Preparation of fluorination catalyst

[0024] Example 1

[0025] 1 kg of antimony chloride and 2 kg of metal sulfate KAl(SO4)2 were put into a coil reactor, hydrogen fluoride was passed into the reactor at a flow rate of 1 mol / h at 150℃, and the fluorination catalyst 1 was prepared by continuously passing for 5 hours.

[0026] Example 2

[0027] 1 kg of antimony chloride and 3 kg of metal sulfate NaCr(SO4)2 were put into a coil reactor, hydrogen fluoride was passed into the reactor at a flow rate of 2 mol / h at 150℃, and the fluorination catalyst 2 was prepared by continuously passing for 3 hours.

[0028] Example 3

[0029] 1 kg of antimony chloride, 2 kg of metal sulfate KAl(SO4)2, 1 kg of NaCr(SO4)2 and 1 kg of KCr (SO4)2 were put into a coil reactor, hydrogen fluoride was passed into the reactor at a flow rate of 3 mol / h at 100℃, and the fluorination catalyst 3 was prepared by continuously passing for 2 hours.

[0030] Example 4

[0031] 1 kg of antimony chloride, 2 kg of metal sulfate KAl(SO4)2, 1 kg of NaCr(SO4)2 and 2 kg of KCr (SO4)2 were put into a coil reactor, hydrogen fluoride was passed into the reactor at a flow rate of 3 mol / h at 120℃, and the fluorination catalyst 4 was prepared by continuously passing for 2 hours.

[0032] Example 5

[0033] Put 1 kg of antimony chloride and 2 kg of metal sulfate NaFe(SO4)2 into a coil reactor, pass hydrogen fluoride into the reactor at a flow rate of 2 mol / h at 150°C for 3 hours to obtain fluorination catalyst 5.

[0034] II. Preparation of methyl perfluoroisobutyl ether

[0035] The octafluoroisobutene methanol absorption liquid used in the example is prepared by spraying excess methanol to absorb octafluoroisobutene gas.

[0036] Example 6

[0037] Vaporize 200 kg (1 kmol) of octafluoroisobutene methanol absorption liquid (feed rate 1 kmol / h based on octafluoroisobutene) in a closed gas cabinet, then pass it together with 71 kg (1 kmol) of chlorine (feed rate 1 kmol / h) into a chlorination coil reactor to carry out chlorination reaction at a reaction temperature of 300°C to obtain heptafluorodichloroisobutyl methyl ether.

[0038] Pass the heptafluorodichloroisobutyl methyl ether obtained above together with 40 kg (2 kmol) of anhydrous hydrogen fluoride (feed rate 2 kmol / h) into a fluorination coil reactor loaded with fluorination catalyst 1 to carry out fluorination reaction at a reaction temperature of 300°C to obtain methyl perfluoroisobutyl ether.

[0039] After the reaction is completed, cool the methyl perfluoroisobutyl ether obtained above, carry out rectification treatment, and analyze the product by gas chromatography, which has a content of ≥99%.

[0040] Example 7

[0041] Vaporize 200 kg (1 kmol) of octafluoroisobutene methanol absorption liquid (feed rate 1 kmol / h based on octafluoroisobutene) in a closed gas cabinet, then pass it together with 142 kg (2 kmol) of chlorine (feed rate 2 kmol / h) into a chlorination coil reactor to carry out chlorination reaction at a reaction temperature of 350°C to obtain heptafluorodichloroisobutyl methyl ether.

[0042] Pass the heptafluorodichloroisobutyl methyl ether obtained above together with 50 kg (2.5 kmol) of anhydrous hydrogen fluoride (feed rate 2.5 kmol / h) into a fluorination coil reactor loaded with fluorination catalyst 2 to carry out fluorination reaction at a reaction temperature of 350°C to obtain methyl perfluoroisobutyl ether.

[0043] After the reaction is completed, cool the methyl perfluoroisobutyl ether obtained above, carry out rectification treatment, and analyze the product by gas chromatography, which has a content of ≥99%.

[0044] Example 8

[0045] The methanol absorption solution of 200 kg (1 kmol) of octafluoroisobutene was vaporized (feed rate 1 kmol / h based on octafluoroisobutene) in a closed gas holder, and then passed into a chlorination coil reactor together with 106.5 kg (1.5 kmol) of chlorine (feed rate 1.5 kmol / h) to perform a chlorination reaction at a reaction temperature of 320°C, to obtain heptafluorodichloroisobutyl methyl ether.

[0046] The above-obtained heptafluorodichloroisobutyl methyl ether was passed into a fluorination coil reactor loaded with fluorination catalyst 3 together with 40 kg (2 kmol) of anhydrous hydrogen fluoride (feed rate 2 kmol / h) to perform a fluorination reaction at a reaction temperature of 320°C, to obtain methyl perfluoroisobutyl ether.

[0047] After the reaction was completed, the above-obtained methyl perfluoroisobutyl ether was subjected to cooling and rectification treatment, and the product content was analyzed by gas chromatography to be ≥ 99%.

[0048] Example 9

[0049] The methanol absorption solution of 200 kg (1 kmol) of octafluoroisobutene was vaporized (feed rate 1 kmol / h based on octafluoroisobutene) in a closed gas holder, and then passed into a chlorination coil reactor together with 71 kg (1 kmol) of chlorine (feed rate 1 kmol / h) to perform a chlorination reaction at a reaction temperature of 300°C, to obtain heptafluorodichloroisobutyl methyl ether.

[0050] The above-obtained heptafluorodichloroisobutyl methyl ether was passed into a fluorination coil reactor loaded with fluorination catalyst 4 together with 40 kg (2 kmol) of anhydrous hydrogen fluoride (feed rate 2 kmol / h) to perform a fluorination reaction at a reaction temperature of 300°C, to obtain methyl perfluoroisobutyl ether.

[0051] After the reaction was completed, the above-obtained methyl perfluoroisobutyl ether was subjected to cooling and rectification treatment, and the product content was analyzed by gas chromatography to be ≥ 99%.

[0052] Example 10

[0053] The methanol absorption solution of 200 kg (1 kmol) of octafluoroisobutene was vaporized (feed rate 1 kmol / h based on octafluoroisobutene) in a closed gas holder, and then passed into a chlorination coil reactor together with 71 kg (1 kmol) of chlorine (feed rate 1 kmol / h) to perform a chlorination reaction at a reaction temperature of 300°C, to obtain heptafluorodichloroisobutyl methyl ether.

[0054] The above obtained heptafluorodichloroisobutyl methyl ether was introduced into a fluorination coil reactor loaded with a fluorination catalyst 5 together with 60 kg (3 kmol) of anhydrous hydrogen fluoride (feed rate 3 kmol / h) to perform a fluorination reaction at a reaction temperature of 300°C to obtain methyl perfluoroisobutyl ether.

[0055] After the reaction was completed, the above obtained methyl perfluoroisobutyl ether was subjected to cooling and rectification treatment, and was analyzed by gas chromatography to find that the product content was ≥ 99%.

[0056] The coil diameter of the chlorination coil reactor used in Examples 6-10 was 3 cm and the length was 64 m, and the coil diameter of the fluorination coil reactor was 1.5 cm and the length was 36 m.

[0057] Of course, the present application can have other various embodiments, and those skilled in the art can make various corresponding changes and modifications according to the present application without departing from the spirit and essence of the present application, and these corresponding changes and modifications shall all belong to the protection scope of the claims of the present application.

Claims

1. A method for preparing a methyl perfluoroisobutyl ether, characterized in that, Includes the following steps: (1) In a closed gas holder, the octafluoroisobutylene methanol absorbent liquid is vaporized and then introduced into a chlorination coil reactor together with chlorine gas to carry out a chlorination reaction to obtain heptafluorodichloroisobutyl methyl ether. (2) The heptafluorodichloroisobutyl methyl ether obtained in step (1) is fed together with anhydrous hydrogen fluoride into a fluorination coil reactor loaded with a fluorination catalyst to carry out a fluorination reaction and obtain methyl perfluoroisobutyl ether.

2. The preparation method according to claim 1, characterized in that, The diameter of the chlorination coil reactor described in step (1) is 3 cm and the length is 64 m.

3. The preparation method according to claim 1 or 2, characterized in that, The chlorination reaction in step (1) is carried out at a temperature of 300–350 °C.

4. The preparation method according to claim 1, characterized in that, The molar ratio of octafluoroisobutylene to chlorine is 1:1 to 2.

5. The preparation method according to claim 1, characterized in that, The diameter of the fluorinated coil reactor in step (2) is 1.5 cm and the length is 36 m.

6. The preparation method according to claim 1 or 5, characterized in that, The temperature of the fluorination reaction in step (2) is 300-350℃.

7. The preparation method according to claim 1, characterized in that, The molar ratio of octafluoroisobutylene to hydrogen fluoride is 1:1 to 3.

8. The preparation method according to claim 1, characterized in that, The fluorination catalyst described in step (2) is made from antimony chloride and a metal sulfate co-catalyst.

9. The preparation method according to claim 8, characterized in that, The mass ratio of antimony chloride to co-catalyst is 1:2 to 5.

10. The preparation method according to claim 8 or 9, characterized in that, The preparation method of the fluorination catalyst is as follows: A fluorination catalyst is prepared by placing a metal sulfate and antimony chloride together in a coil reactor and introducing excess hydrogen fluoride into the reactor at a temperature of 100–150°C. The metal sulfate is one or more of NaAl(SO4)2, KAl(SO4)2, NaCr(SO4)2, KCr(SO4)2, NaFe(SO4)2, KFe(SO4)2, NaCr(SO4)2, and KCr(SO4)2.