JP2024054626A - Carbonyl fluoride manufacturing method and manufacturing apparatus - Google Patents

Abstract

[Problem] The present invention provides a method and apparatus for continuously producing carbonyl fluoride using a highly safe and simple process. [Solution] A method for producing carbonyl fluoride, which comprises reacting gaseous hexafluoropropene with oxygen gas in a tubular reactor at a temperature of 230°C to 300°C without using a solvent, to continuously synthesize carbonyl fluoride. [Selected Figure] Figure 1

Description

The present invention relates to a method and apparatus for producing carbonyl fluoride.

Carbonyl fluoride is a useful compound as a raw material for various higher fluorine compounds, a fluorinating agent, and a cleaning gas for semiconductor manufacturing. In particular, it is a very useful compound as a raw material for producing perfluoromethyl vinyl ether by reacting with hexafluoropropene oxide.

As a method for producing carbonyl fluoride, Patent Document 1 discloses a method in which carbon monoxide and fluorine gas are reacted directly in the gas phase in the presence of an inert gas. Patent Document 2 discloses a method in which carbon monoxide and fluorine gas are reacted in an inert solvent. However, both methods use highly reactive fluorine gas as a raw material, so safety and handling measures are essential, and since the reaction generates intense heat, measures to remove the heat are also necessary. Furthermore, although these methods recommend carrying out the reaction in an inert gas or inert solvent to suppress heat generation, a step of separating them is required, which can complicate the process.

Patent Document 3 discloses a method of obtaining carbonyl fluoride by reacting tetrafluoroethylene gas with oxygen. However, this method is carried out at high temperatures, which increases the possibility of a disproportionation reaction of tetrafluoroethylene. In addition, although a high-temperature reaction microreactor is used as the reactor, tetrafluoroethylene easily self-polymerizes, and the reaction tube may become clogged with precipitates, which increases the frequency of maintenance and makes this method difficult to say is industrially advantageous.

Patent Document 4 discloses a method of obtaining carbonyl fluoride by supplying carbon monoxide to a metal fluoride in a plasma reactor and reacting it. However, this technology requires the supply of an excess amount of the raw material carbon monoxide to drive the reaction, and the outlet gas contains a large amount of unreacted carbon monoxide. This requires a step of separating and recovering the unreacted raw material, which can complicate the process. In addition, the metal fluoride in the plasma reactor needs to be replaced periodically, making the use of a plasma reactor extremely disadvantageous for industrial production.

JP 2003-267712 A International Publication No. WO 2006/64917 JP 2013-14500 A International Publication No. WO 96/19409

In light of this background, the present invention provides a method and apparatus that can continuously produce carbonyl fluoride using a highly safe and simple process.

In the method for producing carbonyl fluoride according to this embodiment, gaseous hexafluoropropene and oxygen gas are reacted in a tubular reactor at a temperature of 230°C to 330°C without using a solvent, to continuously synthesize carbonyl fluoride.

The carbonyl fluoride manufacturing apparatus according to this embodiment includes a first tank filled with gaseous hexafluoropropene, a second tank filled with oxygen gas, and a tubular reactor that reacts the hexafluoropropene continuously supplied from the first tank with the oxygen gas continuously supplied from the second tank at a temperature of 230°C or higher and 330°C or lower, and the tubular reactor does not contain a solvent.

The present invention provides a method and apparatus that can continuously produce carbonyl fluoride using a highly safe and simple process.

1 is a schematic diagram showing an embodiment of an apparatus for producing carbonyl fluoride according to the present invention.

<Production of Carbonyl Fluoride>
In this embodiment, gaseous hexafluoropropene (hereinafter also referred to as "HFP") and oxygen gas are used as raw materials, and carbonyl fluoride (COF ₂ ) is continuously synthesized in a tubular reactor without using a solvent. That is, carbonyl fluoride is synthesized by a gas-phase reaction between gaseous HFP and oxygen gas. Although the reaction of producing carbonyl fluoride generates a large amount of heat, the target substance can be obtained safely and continuously by using a tubular reactor that can have a large heat transfer area per unit volume. When synthesizing carbonyl fluoride using a solvent, a process of dissolving the raw material HFP in the solvent is required, and a process of separating the solvent is required because there is a possibility that a certain amount of the solvent may be entrained as a gas or mist in the synthesis gas containing carbonyl fluoride. In this embodiment, since carbonyl fluoride is synthesized without using a solvent, these processes are not necessary. As a result, the target substance carbonyl fluoride can be obtained continuously by a very simple process. In addition, mass production is possible by arranging tubular reactors in parallel (numbering up), and it is possible to increase the production volume without implementing scale-up, which is technically difficult. Furthermore, improvement of the basic unit can be expected, and since there is no need to treat the solvent as waste, the burden on the environment can be reduced. In addition, HFP and oxygen used as raw materials are stable and low-toxic substances, so they are highly safe and easy to handle.

Figure 1 shows an example of a carbonyl fluoride manufacturing apparatus according to this embodiment. As shown in Figure 1, the carbonyl fluoride manufacturing apparatus 10 includes a first tank (cylinder) 1 filled with gaseous HFP as a raw material and a second tank (cylinder) 2 filled with oxygen gas. The flow rates of HFP and oxygen are adjusted by mass flow controllers 3 in the downstream direction. A tubular reactor 5 is immersed in an oil bath 4, and the reaction temperature in the tubular reactor 5 is adjusted by the oil bath 4, and the reaction pressure is adjusted by a back pressure valve 6. HFP and oxygen are continuously supplied from the first tank 1 and the second tank 2, respectively, and the gases supplied react in the heating section of the tubular reactor, synthesizing carbonyl fluoride as the reaction product 7. In addition to the target substance carbonyl fluoride, the reaction product 7 may also contain by-products such as hexafluoropropene oxide, carbon dioxide, trifluoroacetyl fluoride, unreacted HFP, and oxygen. Hexafluoropropene oxide, which is produced as a by-product, has a higher boiling point and is less toxic than carbonyl fluoride, so carbonyl fluoride can be easily and safely separated from hexafluoropropene oxide.

The amount of HFP supplied is not particularly limited, and can be set arbitrarily so that the reaction time (residence time) falls within the desired range depending on the volume (reaction tube length, reaction tube diameter) of the tubular reactor used.

The amount of oxygen supplied is not particularly limited, but is preferably 0.1 to 5 times the amount of HFP supplied by molar ratio, more preferably 0.5 to 1.5 times the amount of HFP supplied by molar ratio from the viewpoint of economic efficiency and safety, and even more preferably 0.9 to 1.2 times the amount of HFP supplied by molar ratio.

The tubular reactor used in the synthesis of carbonyl fluoride is preferably a copper tubular reactor. By using a copper tubular reactor, it is believed that copper functions as a catalyst for the production of carbonyl fluoride, and the synthesis of carbonyl fluoride can be promoted. It is preferable that such a tubular reactor has a coiled reaction tube structure so that as long as possible of the reaction tube can be immersed in the oil bath.

Since the production of carbonyl fluoride is a reaction that generates a large amount of heat, the heat transfer area per unit volume can be increased by using a tubular reactor with a small inner diameter. Therefore, the inner diameter (tube diameter) of the tubular reactor is preferably 10 mm or less, more preferably 5 mm or less, and even more preferably 3 mm or less. By making the inner diameter of the tubular reactor 10 mm or less, it is possible to quickly release heat, making it possible to produce carbonyl fluoride more safely. In addition, there is no particular limit to the length of the tubular reactor, but it is preferably 0.5 m or more and 100 m or less, and more preferably 1 m or more and 50 m or less.

The reaction temperature (oil bath temperature) between HFP and oxygen is 230°C or higher and 300°C or lower, and preferably 230°C or higher and 260°C or lower. A reaction temperature of 230°C or higher can suppress the production of the by-product hexafluoropropene oxide and increase the selectivity of carbonyl fluoride. A reaction temperature of 300°C or lower can increase safety in the synthesis of carbonyl fluoride.

The reaction pressure between HFP and oxygen is not particularly limited as long as it is equal to or less than the vapor pressure of HFP (40°C, 1.02 MPaG), and can be set arbitrarily, preferably from 0 MPaG to 1.0 MPaG, and more preferably from 0.2 MPaG to 0.8 MPaG.

HFP and oxygen react by being heated in the heating section of a tubular reactor immersed in an oil bath. The reaction time (residence time) of HFP and oxygen in the heating section is preferably 10 seconds or more and 1000 seconds or less, and from the viewpoint of the yield of the obtained carbonyl fluoride, it is more preferably 100 seconds or more and 500 seconds or less, further preferably 200 seconds or more and 400 seconds or less, and particularly preferably 210 seconds or more and 320 seconds or less. In particular, by making the reaction time of HFP and oxygen in the heating section 210 seconds or more and 320 seconds or less, the conversion rate of HFP can be significantly improved and the selectivity of carbonyl fluoride can be increased.

Based on the above embodiment, the present invention relates to the following [1] to [5].
[1] A method for producing carbonyl fluoride, comprising reacting gaseous hexafluoropropene with oxygen gas in a tubular reactor at a temperature of 230° C. or higher and 300° C. or lower without using a solvent, to continuously synthesize carbonyl fluoride.
[2] The method for producing carbonyl fluoride according to the above [1], wherein the tubular reactor is a copper tubular reactor.
[3] The method for producing carbonyl fluoride according to the above [1] or [2], wherein the inner diameter of the tubular reactor is 10 mm or less.
[4] The method for producing carbonyl fluoride according to any one of [1] to [3] above, wherein the reaction time of the hexafluoropropene and the oxygen gas in the heating section of the tubular reactor is 10 seconds or more and 1000 seconds or less.
[5] a first tank filled with gaseous hexafluoropropene;
a second tank filled with oxygen gas;
a tubular reactor for reacting hexafluoropropene continuously supplied from the first tank with oxygen gas continuously supplied from the second tank at a temperature of 230° C. or higher and 300° C. or lower;
1. The apparatus for producing carbonyl fluoride, wherein the tubular reactor does not contain a solvent.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and includes all aspects included in the concept of the present invention and the scope of the claims, and can be modified in various ways within the scope of the present invention.

The following describes examples of the present invention, but the present invention is not limited to these examples as long as they do not exceed the spirit of the invention.

Example 1
A copper tubular reactor with an inner diameter of 1.58 mm and a length of 10 m was used as the reaction tube. The raw materials, gaseous HFP and oxygen gas, were continuously supplied to the reaction tube at a stoichiometric ratio of 1:1 so that the reaction time (residence time) in the reaction tube was 216 seconds. The reaction tube was immersed in an oil bath whose temperature was adjusted to 230° C., and the pressure in the reaction tube was adjusted to 0.5 MPaG by a back pressure valve. Thereafter, the outlet gas was sampled, and the composition of the synthesized gas was confirmed by gas chromatography (GC). The results are shown in Table 1. As shown in Table 1, the conversion rate of HFP was 84.2%, the selectivity of carbonyl fluoride was 73.6%, and the selectivity of hexafluoropropene oxide (HFPO) was 4.5%.

Example 2
The same operation as in Example 1 was carried out, except that the gaseous HFP and oxygen gas were retained in the reaction tube for 224 seconds. The results are shown in Table 1. As shown in Table 1, the conversion of HFP was 89.8%, the selectivity of carbonyl fluoride was 82.0%, and the selectivity of hexafluoropropene oxide was 3.4%.

Example 3
The same operation as in Example 1 was carried out except that the gaseous HFP and oxygen gas were retained in the reaction tube for 320 seconds. The results are shown in Table 1. As shown in Table 1, the conversion of HFP was 89.7%, the selectivity of carbonyl fluoride was 90.4%, and the selectivity of hexafluoropropene oxide was 3.9%.

<Comparative Example 1>
The same operation as in Example 1 was carried out except that the reaction temperature was set to 220° C. and the gaseous HFP and oxygen gas were retained in the reaction tube for 379 seconds. The results are shown in Table 1. As shown in Table 1, the conversion of HFP was 98.6%, the selectivity of carbonyl fluoride was 59.6%, and the selectivity of hexafluoropropene oxide was 28.4%.

<Comparative Example 2>
The same operation as in Example 1 was carried out except that the reaction temperature was set to 220° C. and the gaseous HFP and oxygen gas were retained in the reaction tube for 292 seconds. The results are shown in Table 1. As shown in Table 1, the conversion of HFP was 91.5%, the selectivity of carbonyl fluoride was 41.1%, and the selectivity of hexafluoropropene oxide was 21.7%.

In Examples 1 to 3 and Comparative Examples 1 and 2, synthetic gas is analyzed by GC, and inerts are detected as gases with short retention times. Generally, air (nitrogen, oxygen, carbon dioxide, etc.) corresponds to inerts, and although air may be mixed in when sampling gas or introducing it into an analytical device, it is also possible that carbon dioxide is generated by the reaction between HFP and oxygen and this is detected. However, since the GC column and conditions used in this study cannot separate and detect nitrogen, oxygen, and carbon dioxide, inerts are also considered to include carbon dioxide that may be generated as a by-product.

In Examples 1 to 3 and Comparative Examples 1 and 2, if the selectivity of carbonyl fluoride was 70% or more, it was evaluated that carbonyl fluoride was continuously synthesized. As shown in Table 1, in Examples 1 to 3, it was confirmed that carbonyl fluoride was continuously synthesized by the gas-phase reaction of gaseous HFP and oxygen gas. Furthermore, since Examples 1 to 3 did not require a process for separating the solvent, the target substance, carbonyl fluoride, was continuously obtained safely in a very simple process. On the other hand, in Comparative Examples 1 and 2, where the reaction temperature was 220°C, the desired selectivity of carbonyl fluoride could not be achieved.

1 First tank, 2 Second tank, 3 Mass flow controller, 4 Oil bath, 5 Tubular reactor, 6 Back pressure valve, 7 Reaction product, 10 Carbonyl fluoride production apparatus

Claims (5)

A method for producing carbonyl fluoride, characterized by reacting gaseous hexafluoropropene with oxygen gas in a tubular reactor at a temperature of 230°C to 300°C without using a solvent, to continuously synthesize carbonyl fluoride. The method for producing carbonyl fluoride according to claim 1, wherein the tubular reactor is a copper tubular reactor. The method for producing carbonyl fluoride according to claim 1 or 2, wherein the inner diameter of the tubular reactor is 10 mm or less. The method for producing carbonyl fluoride according to claim 1 or 2, wherein the reaction time of the hexafluoropropene and the oxygen gas in the heating section of the tubular reactor is 10 seconds or more and 1000 seconds or less. a first tank filled with gaseous hexafluoropropene;
a second tank filled with oxygen gas;
a tubular reactor for reacting hexafluoropropene continuously supplied from the first tank with oxygen gas continuously supplied from the second tank at a temperature of 230° C. or higher and 300° C. or lower;
The hexafluoropropylene oxide production apparatus is characterized in that the tubular reactor does not contain a solvent.

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