CN106893090A - The preparation method and products therefrom of a kind of perfluoro polyether oil - Google Patents

Abstract

The invention provides a method for preparing perfluoropolyether oil, which comprises the steps of: 1) using hexafluoropropylene and/or tetrafluoroethylene as a raw material of an unsaturated fluoroether polymer obtained by photocatalysis, and placing it in a gas-liquid reaction device; 2) Feed the mixed gas of fluorine gas and nitrogen gas into the gas-liquid reaction equipment, the ratio of fluorine gas and nitrogen gas is 1/4 to 1/1; 3) After 6-12 hours of reaction, stop the ventilation, and put the gas-liquid reaction equipment The inner material is released, filtered and washed with water to obtain the product. The present invention uses relatively high concentration of fluorine gas to directly fluorinate carboxyl and carbonyl groups in perfluorinated organic matter, and strictly requires control of the fluorine gas concentration in the fluorination process to avoid non-reaction due to too low fluorine gas concentration, or formation of CF due to too high fluorine gas concentration ₄ and CF ₂ O, the effect of fluorination is basically complete.

Description

A kind of preparation method of perfluoropolyether oil and obtained product

technical field

The invention belongs to the field of organic chemistry, and in particular relates to a preparation method of perfluoropolyether.

Background technique

Perfluoropolyether (abbreviated as PFPE) is a colorless, odorless, transparent liquid at room temperature, because it has saturated end groups and a large number of fluorinated groups, it has heat resistance, oxidation resistance, radiation resistance, corrosion resistance, low volatility, non-toxic Combustion and other characteristics, as well as good comprehensive properties such as compatibility with plastics, elastomers, and metal materials, thus becoming an extremely reliable lubricant in harsh environments, widely used in chemical, electronic, electrical, mechanical, magnetic media, nuclear, etc. Industry, aerospace and other fields.

As a fluorinated chemical product, perfluoropolyether oil has problems such as unavailable raw materials and harsh reaction conditions. In the patent CN94116729, the perfluorofluorination under the condition of low fluorine ratio is introduced, and the reaction needs to be carried out under the protection of an inert medium; the perfluorofluorination of poly(tetrahydrofuran) diacetate is introduced in the patent CN94116729. In fluorination, there is a large amount of -COOH in the final fluorination product detected by the instrument, which also shows that it is very difficult to completely react with unsaturated end groups.

Perfluoropolyether oil can be produced by photooxidation reaction with hexafluoropropylene or tetrafluoroethylene, under the action of telogen to generate polyfluoroether oil intermediate product, and then treat carbonyl or carboxyl end groups by different methods to obtain terminal Based saturated fluoroalkyl polyfluoroether oil. The common method is to hydrolyze the carbonyl group to become a carboxyl group, and then turn it into an ester through methanol, or react with a base to form a salt, and then heat to decarboxylate it. These methods all exist problems such as insufficient response, loaded down with trivial details in the process of using. In the field of fluorine gas fluorination, there are many direct fluorination technologies. There are various introductions for perfluorofluorination, and the direct fluorination reactor is very comprehensive, but the introduction of the terminal carboxyl and carbonyl related reactions of perfluoroorganic There are very few, and the parameters of how to control various links in the fluorination process are not detailed.

Contents of the invention

Aiming at the deficiencies in the prior art, the purpose of the present invention is to propose a preparation method of perfluoropolyether oil.

Another object of the present invention is the perfluoropolyether oil prepared by the method.

The technical scheme that realizes the above-mentioned purpose of the present invention is:

A preparation method of perfluoropolyether oil, comprising the steps of:

1) Use hexafluoropropylene and/or tetrafluoroethylene as a raw material to obtain an unsaturated fluoroether polymer through photocatalysis, and place it in a gas-liquid reaction device;

2) Feed the mixed gas of fluorine gas and nitrogen gas into the gas-liquid reaction equipment, the volume ratio (or molar ratio) of fluorine gas and nitrogen gas is 1/4～1/1;

3) After 6-12 hours of reaction, stop the ventilation, discharge the materials in the gas-liquid reaction equipment, filter and wash with water to obtain the product.

Among them, the unsaturated fluoroether polymer obtained by photocatalysis of hexafluoropropylene and/or tetrafluoroethylene, the general formula of the product is CF ₃ CF ₂ CF ₂ O[CF ₂ C(CF ₃ )FO] _m (CF ₂ O) _n COF and/or CF ₃ CF ₂ CF ₂ O[CF ₂ C(CF ₃ )FO] _m (CF ₂ O) _n COOH; in the general formula, unsaturated fluoroether polymers with m>5 and n>5 are residual Liquid, is the raw material of step 1).

Among them, the photocatalytic reaction formula of hexafluoropropylene is as formula (1)

The preparation method of perfluoropolyether oil provided by the invention is fluorinated with get directly

When n>5 and m>the products obtained by photocatalysis of hexafluoropropylene and/or tetrafluoroethylene are defined as raffinate, they cannot be used as fluorine-containing surfactants. The present invention utilizes this part of residual liquid to obtain high value-added perfluoropolyether oil, which brings better economic benefits to enterprises.

In practice, it is found that in step 2), the proportion of fluorine gas is less than 1/4 and hardly reacts, and when the proportion is higher than 1/1, the organic matter is easy to break the chain, so controlling the proportion of fluorine gas is very important for the product of the fluorination reaction . The fluorine gas is fed in at a constant speed, and is passed into the reactor in the form of bubbling. If the speed is too fast or too slow, the reaction will be insufficient.

Preferably, the gas-liquid reaction equipment described in step 2) is a bubbling gas-liquid reaction equipment, and the gas enters from the lower part of the liquid and exits from the upper part of the liquid.

More preferably, in the step 2), the volume ratio of the mixed gas of fluorine gas and nitrogen gas to the raw material is 2000L: 2.5-3.5kg.

Wherein, the reaction temperature in the step 2) is 30-200°C, preferably 70-100°C.

In step 2), the temperature of the reactor is optimally 70°C to 100°C. When the proportion of fluorine gas is high, the reaction can also be carried out at room temperature or low temperature, but a large amount of HF will remain in the reaction, which increases the subsequent Therefore, step C is carried out at 70°C to 100°C. No acid removal equipment is needed in the system, and HF can be volatilized out of the reactor during the reaction, which greatly reduces the complexity of the fluorination system.

Wherein, the fluorine gas can be prepared by electrolysis, and the nitrogen gas is refined nitrogen with a purity above 99.99%.

Wherein, the mixed gas of fluorine gas and nitrogen is passed into the gas-liquid reaction equipment through the pipeline, and the rotameter of Harmony alloy is arranged on the said pipeline; The inner wall is made of special alloy material; the gas-liquid reaction equipment is provided with a jacket, and hot water is passed into the jacket.

The perfluoropolyether oil prepared by the preparation method of the invention.

The beneficial effects of the present invention are:

The present invention uses relatively high concentration of fluorine gas to directly fluorinate carboxyl and carbonyl groups in perfluorinated organic matter, and strictly requires control of the fluorine gas concentration in the fluorination process to avoid non-reaction due to too low fluorine gas concentration, or formation of CF due to too high fluorine gas concentration ₄ and CF ₂ O, the effect of fluorination is basically complete.

The invention utilizes photocatalysis to produce the raffinate of the perfluorooctanoic acid substitute emulsion, obtains the perfluoropolyether oil with high added value, and brings better economic benefits to enterprises.

The preparation method of polyfluoroether oil provided by the invention is suitable for converting perfluoropolyether carbonyl and carboxyl groups into saturated fluoroalkyl groups, and has the characteristics of simple steps and complete reaction.

detailed description

The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

In the examples, unless otherwise specified, the means used are conventional means in the art.

Example 1:

The raw material is the raffinate of perfluorooctanoic acid substitute obtained by photocatalysis of hexafluoropropylene and tetrafluoroethylene, and a large amount of organic matter in the raffinate has the general formula CF ₃ CF ₂ CF ₂ O[CF ₂ C(CF ₃ )FO]m(CF ₂ O) _n COF and CF ₃ CF ₂ CF ₂ O[CF ₂ C(CF ₃ )FO] _m (CF ₂ O) _n COOH, m>5, n>5.

In the fluorination system, a 3L jacketed reactor is used, the inner wall of the reactor is lined with fluorine-containing plastic, the reactor has a jacket, and hot water is passed into the jacket.

Add 2.7kg of the residual solution of PFOA substitute into the reactor, and the jacket of the reactor is fed with controllable constant temperature hot water to maintain the temperature of the reactor at 70°C. The fluorine gas is prepared by a fluorine-making electrolytic cell with an electrolysis current of 1000A, replacing a 1.1m ³ fluorine gas storage tank, closing the inlet and outlet valves after collecting for 3 hours; feeding refined nitrogen (purity 99.99%, volume content) into the fluorine gas storage tank The gauge pressure is 0.15MPa. As the operation proceeds, the ratio of fluorine gas and nitrogen gas in the storage tank is within a range, which is related to the replacement rate during fluorine production and the purity of fluorine gas produced. The average can be considered to be 0.85:2.5.

The mixed gas in the fluorine gas storage tank is fed into the reactor at a constant flow rate of 200L/h through the pipeline, and a Harmony alloy rotameter is installed on the pipeline. After entering for 10 hours, stop the ventilation, replace and purge with nitrogen, release the liquid phase, filter with a suction filter bottle and filter paper to obtain 2.34 kg of material, and obtain 1.53 kg of transparent liquid after filtration.

Mass spectrometry and nuclear magnetic analysis, the liquid phase does not contain carboxyl and carbonyl groups, it is a saturated organic compound, the structural formula is CF ₃ CF ₂ CF ₂ O[CF ₂ C(CF ₃ )FO] _m (CF ₂ O) _n CF ₃ , and the molecular weight of the product is 12000. The infrared spectrum of the raw material before fluorination shows broad peaks at 3448.71cm-1, 236, 177cm-1, and at 1771.28cm-1, 1730.30cm-1, 983.67cm-1, 800.74cm-1, 744.01cm-1, 700.24 cm-1, 630.30cm-1 appears a sharp peak or a shoulder peak, indicating that the raw material is a compound with carboxyl and carbonyl groups; in the infrared spectrum of the product after fluorination, a broad peak appears at 1236.98cm-1, and at 893.16cm-1,868.76cm-1 1, 809.37cm-1, 746.32cm-1, 713.38cm-1, 529.47cm-1, 467.38cm-1 appear sharp peaks or shoulders, indicating that there are no carboxyl and carbonyl groups in the product.

The boiling point of the product is 300°C, and the appearance is a transparent liquid.

Example 2

Add 2.7kg of the residual solution of PFOA substitute into the reactor, and inject controllable constant-temperature hot water into the jacket of the reactor to maintain the temperature of the reactor at 80°C. The fluorine gas is prepared by electrolysis of calcium fluoride, the electrolysis current is 1000A, the 1.1m ³ fluorine gas storage tank is replaced, the inlet and outlet valves are closed after 3 hours of collection; the refined nitrogen (purity 99.99%, volume content) is pressed into the fluorine gas storage tank The gauge pressure is 0.20MPa. At this time, the volume ratio of fluorine gas and nitrogen gas in the storage tank is 1:2.

The mixed gas in the fluorine gas storage tank is fed into the reactor at a constant flow rate of 200L/h through the pipeline, and a Harmony alloy rotameter is installed on the pipeline. After entering for 10 hours, stop the ventilation, replace and purge with nitrogen, release the liquid phase, filter with a suction filter bottle and filter paper to obtain 2.56 kg of material, and obtain 1.55 kg of transparent liquid after filtration.

Other operations are the same as in Example 1.

According to mass spectrometry and NMR analysis, the structural formula is CF ₃ CF ₂ CF ₂ O[CF ₂ C(CF ₃ )FO] _m (CF ₂ O) _n CF ₃ , and the molecular weight of the product is 15,000.

Example 3

The raw material is the perfluorooctanoic acid substitute raffinate obtained by photocatalysis of tetrafluoroethylene, and 2.6 kg of perfluorooctanoic acid substitute raffinate is added to the reactor, and the reactor jacket is fed with controllable constant temperature hot water to maintain the reactor temperature at 90 °C. The fluorine gas is prepared by electrolysis of calcium fluoride, the electrolysis current is 1000A, and the fluorine gas storage tank of 1.1m3 is replaced, and the inlet and outlet valves are closed after collecting for ³ hours; The gauge pressure is 0.20MPa. At this time, the volume ratio of fluorine gas and nitrogen gas in the storage tank is 1:3.

The mixed gas in the fluorine gas storage tank is fed into the reactor at a constant flow rate of 200L/h through the pipeline, and a Harmony alloy rotameter is installed on the pipeline. Stop ventilation after 9 hours, replace and purge with nitrogen, release the liquid phase, filter with a suction filter bottle and filter paper to obtain 2.66 kg of material, and obtain 1.80 kg of transparent liquid after filtration.

Other operations are the same as in Example 1.

According to mass spectrometry and NMR analysis, the structural formula is CF ₃ CF ₂ CF ₂ O[CF ₂ C(CF ₃ )FO] _m (CF ₂ O) _n CF ₃ , and the molecular weight of the product is 11,000.

The above embodiments are only descriptions of preferred implementations of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, ordinary engineers and technicians in the field may make various modifications to the technical solutions of the present invention. and improvements, all should fall within the scope of protection determined by the claims of the present invention.

Claims (9)

1. a kind of preparation method of perfluoro polyether oil, it is characterised in that including step：

1) gas liquid reaction, as raw material, is placed in through unsaturated fluorine ether polymer obtained by photocatalysis with hexafluoropropene and/or tetrafluoroethene In equipment；

2) to the gaseous mixture that fluorine gas and nitrogen are passed through in gas-liquid reaction equipment, the volume ratio of fluorine gas and nitrogen is 1/4~1/1；

3) reacted by 6~12 hours, stop ventilation, material in gas-liquid reaction equipment is released, filtering, washing obtain product.

2. preparation method according to claim 1, it is characterised in that hexafluoropropene and/or tetrafluoroethene are obtained through photocatalysis The unsaturated fluorine ether polymer for arriving, its formula is CF₃CF₂CF₂O[CF₂C(CF₃)FO]_m(CF₂O)_nCOF and/or CF₃CF₂CF₂O [CF₂C(CF₃)FO]_m(CF₂O)_nCOOH；In formula the unsaturated fluorine ether polymer of m ＞ 5 and n ＞ 5 be raffinate, be step 1) original Material.

3. preparation method according to claim 1, it is characterised in that step 2) described in gas-liquid reaction equipment be bubble type Gas-liquid reaction equipment, gas from liquid bottom enters, is discharged from liquid top.

4. according to any described preparation method of claims 1 to 3, it is characterised in that the step 2) in, the fluorine gas that is passed through and The gaseous mixture volume of nitrogen is 2000L with the mass ratio of raw material：2.5~3.5kg.

5. according to any described preparation method of claims 1 to 3, it is characterised in that the step 2) in reaction temperature be 30 ~200 DEG C.

6. preparation method according to claim 5, it is characterised in that the reaction temperature is 70~80 DEG C.

7. according to any described preparation method of claims 1 to 3, it is characterised in that the fluorine gas is obtained for electrolytic preparation, institute Nitrogen is stated for smart nitrogen of the purity more than 99.99%.

8. according to any described preparation method of claims 1 to 3, it is characterised in that the gaseous mixture of fluorine gas and nitrogen is through pipeline Gas-liquid reaction equipment is passed through, the spinner flowmeter for breathing out magnetic alloy is set on the pipeline；The gas-liquid reaction equipment sets in inwall It is equipped with fluoro-containing plastic lining or is made inwall with Hastelloy material；The gas-liquid reaction equipment is provided with chuck, in chuck It is passed through hot water.

9. the perfluoro polyether oil that any described preparation method of claim 1~8 is prepared.