JP7744588B2 - Methods for producing alkenes - Google Patents

Description

This disclosure relates to a method for producing alkenes.

Patent Document 1 discloses that in the presence of a catalyst made of palladium or platinum supported on activated carbon,
A process for preparing trifluoroethylene is disclosed which comprises contacting chlorotrifluoroethylene with hydrogen.

Special publication 2013-534529

The objective of this disclosure is to produce hydrogenated alkenes through hydrogen substitution.

This disclosure includes the following configurations:

Item 1.
General formula (1):

(In the formula, R ¹ , R ² , and R ³ are the same or different and represent fluorine or a perfluoroalkyl group.)
A method for producing an alkene represented by the formula:
General formula (2):

(In the formula, X is a halogen atom, and R ¹ , R ² , and R ³ are the same or different and represent fluorine or a perfluoroalkyl group. In the formula, when X is a chlorine atom, at least one of R ¹ , R ² , and R ³ represents a perfluoroalkyl group.)
in the presence of an activated carbon catalyst supporting a noble metal or a rare metal.

Item 2.
2. The method according to Item 1, wherein the hydrogenation reaction is carried out in a gas phase.

Item 3.
3. The production method according to Item 1 or 2, wherein the noble metal or rare metal is at least one noble metal or rare metal selected from the group consisting of palladium (Pd), platinum (Pt), rhodium (Rh), ruthenium (Ru), and manganese (Mn).

Item 4.
_CF3 -CF=CH- _CF3 ;
_CF3 -CFH-CFH- _CF3 ; and
A composition comprising: _CF3 -CFH-CFH- _CF2H ;

Item 5.
Item 5. The composition according to item 4, which is used as an etching gas, a refrigerant, a heat transfer medium, a deposit gas, a building block for organic synthesis, or a cleaning gas.

According to the present disclosure, hydrogenated alkenes can be produced efficiently through hydrogen substitution.

In this specification, the term "containing" encompasses the concepts of "comprise," "consist essentially of," and "consist only of." Furthermore, in this specification, when a numerical range is expressed as "A to B," it means A or more and B or less.

As a result of extensive research, the inventors have discovered that by carrying out the hydrogenation reaction of the raw material alkene in the presence of a palladium-supported activated carbon catalyst, the hydrogenation reaction can be carried out efficiently, and hydrogenated alkenes can be produced with high conversion (yield) and high selectivity.

This disclosure was completed as a result of further research based on this knowledge.

This disclosure includes the following embodiments:

General formula (1) of the present disclosure:

(In the formula, R ¹ , R ² , and R ³ are the same or different and represent fluorine or a perfluoroalkyl group.)
The method for producing an alkene represented by the formula:
General formula (2):

(In the formula, X is a halogen atom, and R ¹ , R ² , and R ³ are the same or different and represent fluorine or a perfluoroalkyl group. In the formula, when X is a chlorine atom, at least one of R ¹ , R ² , and R ³ represents a perfluoroalkyl group.)
in the presence of an activated carbon catalyst supporting a noble metal or a rare metal.

In the manufacturing method of the present disclosure, the hydrogenation reaction step is preferably carried out in the gas phase.

In the manufacturing method of the present disclosure, preferably, the noble metal or rare metal is at least one noble metal or rare metal selected from the group consisting of palladium (Pd), platinum (Pt), rhodium (Rh), ruthenium (Ru), and manganese (Mn).

The composition of the present disclosure comprises:
_CF3 -CF=CH- _CF3 ;
_CF3 -CFH-CFH- _CF3 ; and
Contains _CF3 -CFH-CFH- _CF2H ;

The compositions of the present disclosure are preferably used as etching gases, refrigerants, heat transfer media, deposition gases, building blocks for organic synthesis, or cleaning gases.

By satisfying the above requirements, the present disclosure enables the hydrogenation reaction to proceed efficiently, producing hydrogenated alkenes with high conversion (yield) and high selectivity.

In this disclosure, "conversion rate" means the ratio (mol%) of the total molar amount of compounds other than the raw material compound (such as hydrogenated alkenes) contained in the gas effluent from the reactor outlet to the molar amount of the raw material compound (alkenes containing halogen atoms) supplied to the reactor.

In this disclosure, "selectivity" means the ratio (mol%) of the total molar amount of the target compound (hydrogenated alkene) contained in the effluent gas from the reactor outlet to the total molar amount of compounds other than the feed compound (such as hydrogenated alkenes) in the effluent gas.

The alkene production method disclosed herein can efficiently hydrogenate the halogen-containing alkene, which is the raw material compound, and produce hydrogenated alkenes with high conversion (yield) and high selectivity.

(1) Raw Material Compound The raw material compound of the present disclosure is represented by the general formula (2):

(In the formula, X is a halogen atom, and R ¹ , R ² , and R ³ are the same or different and represent fluorine or a perfluoroalkyl group. In the formula, when X is a chlorine atom, at least one of R ¹ , R ² , and R ³ represents a perfluoroalkyl group.)
It is an alkene represented by the formula:

In the alkene formula (2), X is a halogen atom, and R ¹ , R ² and R ³ are the same or different and represent fluorine or a perfluoroalkyl group.

In the alkene formula (2), when X is a chlorine atom, at least one of R ¹ , R ² and R ³ represents a perfluoroalkyl group.

Halogen atoms are preferably fluorine atoms, bromine atoms, iodine atoms, and chlorine atoms.

A perfluoroalkyl group is an alkyl group in which all hydrogen atoms have been substituted with fluorine atoms. The perfluoroalkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, even more preferably 1 to 6 carbon atoms, particularly preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms.

The perfluoroalkyl group is preferably a straight-chain or branched-chain perfluoroalkyl group. The perfluoroalkyl group is preferably a trifluoromethyl group (CF ₃ —) or a pentafluoroethyl group (C ₂ F ₅ —).

The alkene represented by general formula (2), which is the raw material compound, preferably has 2 to 8 carbon atoms, more preferably 2 to 4 carbon atoms, and even more preferably 4 carbon atoms, in that the hydrogenation reaction proceeds efficiently in the presence of an activated carbon catalyst supporting a noble metal or a rare metal, and the hydrogenated alkene can be produced with a high conversion rate, yield, and/or high selectivity.

In the alkene represented by the general formula (2) which is the raw material compound, R ¹ , R ² and R ³ are the same or different and represent fluorine or a perfluoroalkyl group.

The alkene represented by the general formula (2) of the raw material compound is preferably perfluoro-2-butene (F ₃ C-CF=CF-CF ₃ ), perfluoro-1-butene (CF ₃ -CF ₂ -CF=CF ₂ ), or the like.

The starting compound, an alkene represented by general formula (2), can be used alone or in combination of two or more types. Commercially available alkenes can also be used.

(2) Hydrogenation Reaction In the hydrogenation reaction step of the present disclosure, the alkene represented by general formula (2) is hydrogenated using palladium-supported activated carbon as a catalyst.

In the hydrogenation reaction step, the alkene represented by general formula (2), which is a raw material compound, preferably has 2 to 8 carbon atoms, more preferably 2 to 4 carbon atoms, and even more preferably 4 carbon atoms, in that hydrogenated alkene can be produced with a high conversion rate, yield, and/or high selectivity.

In the hydrogenation reaction step, the alkene represented by general formula (2) as the raw material compound is efficiently hydrogenated in the presence of a palladium-supported activated carbon catalyst, and the hydrogenated alkene can be produced with a high conversion, yield, and/or high selectivity. Therefore, preferably, R ¹ , R ² , and R ³ are the same or different and represent fluorine or a perfluoroalkyl group.

The alkene represented by general formula (2), which is the raw material compound, is preferably perfluoro-2-butene ( _CF3 -CF=CF- _CF3 ), and the alkene represented by general formula (1), which is the target compound to be hydrogenated, is preferably 1,1,1,2,4,4,4-heptafluoro-2-butene ( _CF3 -CF=CH- _CF3 ) ((Z/E)-1327myz)).

Activated carbon catalyst supporting precious or rare metals
(Precious or rare metal catalyst supported on activated carbon)
The hydrogenation reaction step of the present disclosure involves hydrogenating an alkene represented by general formula (2), which is a raw material compound, using an activated carbon catalyst supporting a noble metal or a rare metal as a catalyst,
The target compound, an alkene represented by general formula (1), preferably 1,1,1,2,4,4,4-heptafluoro-2-butene, is produced by hydrogenation.

The hydrogenation reaction step is preferably carried out in the gas phase.

As a hydrogenation catalyst, the noble or rare metal is preferably at least one noble or rare metal selected from the group consisting of palladium (Pd), platinum (Pt), rhodium (Rh), ruthenium (Ru), and manganese (Mn).

As a hydrogenation catalyst, it is more preferable to use a palladium-on-activated carbon catalyst, in which the noble or rare metal is palladium (Pd) and the carrier is activated carbon, which allows for a high metal surface area and a fast hydrogenation reaction rate.

The particle size of the activated carbon carrier is preferably approximately 0.1 mm to 100 mm.

The amount of palladium supported relative to the total mass of the catalyst used in the hydrogenation reaction step is preferably approximately 0.01% to 20% by mass, and more preferably approximately 0.1% to 10% by mass.

A wide variety of known preparation methods can be used to prepare catalysts. For example, a catalyst in which palladium metal is supported on an activated carbon carrier can be obtained by immersing the activated carbon carrier in a solution containing palladium metal, impregnating the carrier with the solution, and then, if necessary, neutralizing and calcining the carrier. In this case, the amount of precious or rare metal supported on the carrier can be adjusted by adjusting the concentration of the solution, the impregnation time, etc.

Amount of hydrogen used (H ₂ /alkene molar ratio)
In the hydrogenation reaction process of the present disclosure, since the hydrogenated alkene can be produced with a high conversion rate, yield, and/or high selectivity, the amount of hydrogen used is preferably 0.1 to 10 moles per mole of alkene ( _H2 /alkene molar ratio: 0.1 to 10), more preferably 1 to 5 moles ( _H2 /alkene molar ratio: 1 to 5), even more preferably 1 to 3 moles ( _H2 /alkene molar ratio: 1 to 3), and particularly preferably 1.1 moles ( _H2 /alkene molar ratio: 1.1).

Reaction Temperature of Hydrogenation Reaction In the hydrogenation reaction step of the present disclosure, a palladium-supported activated carbon catalyst is used, and the lower limit of the reaction temperature is preferably 100°C or higher, more preferably 150°C or higher, and even more preferably 200°C or higher, from the viewpoints of more efficiently proceeding with the hydrogenation reaction from the raw material compounds, further improving the conversion rate, and enabling the target compound to be obtained with higher selectivity.

In the hydrogenation reaction step, the upper limit of the hydrogenation reaction temperature is preferably 800°C or lower, more preferably 600°C or lower, even more preferably 500°C or lower, and particularly preferably 400°C or lower, from the viewpoint of more efficiently progressing the hydrogenation reaction, further improving the conversion rate, and enabling the target compound to be obtained with higher selectivity, and from the viewpoint of further suppressing a decrease in selectivity due to decomposition or polymerization of the reaction product.

In the hydrogenation reaction step of the present disclosure, the reaction time for the hydrogenation reaction, for example, when a gas-phase flow system is employed, is the contact time (W/F) of the raw material compound with the catalyst [W: weight (g) of metal catalyst, F: flow rate (cc/sec)], from the viewpoint of achieving a particularly high conversion rate by the hydrogenation reaction and obtaining the target compound in a higher yield and with a higher selectivity, preferably 1 g sec/cc to 120 g sec/cc, more preferably 3 g sec/cc to 100 g sec/cc, and even more preferably 5 g sec/cc to 80 g sec/cc. The above W/F specifies the reaction time particularly when a gas-phase flow system reaction is employed.

When using a batch reaction, the contact time can be set appropriately.

The above contact time refers to the time during which the raw material compound (substrate) and catalyst are in contact.

Reaction Pressure of Hydrogenation Reaction In the hydrogenation reaction step of the present disclosure, the reaction pressure for the hydrogenation reaction is preferably −0.05 MPa to 2 MPa, more preferably −0.01 MPa to 1 MPa, and even more preferably atmospheric pressure to 0.5 MPa, from the viewpoint of more efficiently proceeding with the hydrogenation reaction.

In this disclosure, unless otherwise specified, pressure refers to gauge pressure.

In the hydrogenation reaction step of the present disclosure, the reactor into which the raw material compound and the catalyst are introduced and into which the hydrogenation reaction is carried out is not particularly limited in shape or structure as long as it can withstand the above-mentioned temperature and pressure. The reactor for the hydrogenation reaction is preferably a vertical reactor, a horizontal reactor, a multi-tubular reactor, or the like. The material of the reactor for the hydrogenation reaction is preferably glass, stainless steel, iron, nickel, an iron-nickel alloy, or the like.

Gas Phase Reaction The hydrogenation reaction step of the present disclosure is preferably carried out by a gas phase reaction, and can be carried out by either a flow system or a batch system in which a raw material compound (substrate) is continuously charged into a reactor and a target compound is continuously withdrawn from the reactor.

It is preferable to carry out the reaction in a flow mode to prevent the target compound from remaining in the reactor and causing the reaction to proceed excessively.

The hydrogenation reaction step of the present disclosure is preferably carried out in the gas phase, more preferably in a gas phase continuous flow system using a fixed bed reactor. When carried out in a gas phase continuous flow system, the equipment, operation, etc. can be simplified and it is economically advantageous.

The hydrogenation reaction step is preferably carried out in an inert gas atmosphere, hydrogen fluoride gas atmosphere, or the like, to prevent catalyst degradation. Inert gases are preferably nitrogen, helium, argon, or the like. Among inert gases, nitrogen is preferred to reduce costs. The concentration of the inert gas is preferably 0 mol % to 50 mol % of the gas components introduced into the reactor.

When the hydrogenation reaction process is carried out in the gas phase in the presence of a catalyst, the target compound can be obtained with higher selectivity by appropriately adjusting the reaction temperature and reaction time (contact time) to suit the catalyst.

(3) Target Compound The target compound of the present disclosure is represented by the general formula (1):

(In the formula, R ¹ , R ² , and R ³ are the same or different and represent fluorine or a perfluoroalkyl group.)
It is an alkene (hydrogenated alkene) represented by the formula:

In the hydrogenation reaction step, X (a halogen atom) of the raw material compound represented by general formula (2) is replaced with hydrogen to produce a hydrogen-substituted alkene.

In the alkene formula (1), R ¹ , R ² and R ³ may be the same or different and represent fluorine or a perfluoroalkyl group.

A perfluoroalkyl group is an alkyl group in which all hydrogen atoms have been substituted with fluorine atoms. The perfluoroalkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, even more preferably 1 to 6 carbon atoms, particularly preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms.

The perfluoroalkyl group is preferably a straight-chain or branched-chain perfluoroalkyl group. The perfluoroalkyl group is preferably a trifluoromethyl group (CF ₃ —) or a pentafluoroethyl group (C ₂ F ₅ —).

The target alkene represented by general formula (1) is preferably a compound having 2 carbon atoms (C2 compound) to 8 carbon atoms (C8 compound), more preferably a C2 compound to C4 compound, and even more preferably a C4 compound, because the target alkene (halogen atom) represented by general formula ( ₂ ), a raw material compound, can be efficiently hydrogenated in the presence of a _palladium - _supported activated carbon catalyst, and the hydrogenated _alkene can be produced with high conversion, yield, and/or _high selectivity.

The target compound, alkene represented by general formula (1), is preferably a compound in which R 1 , R 2 , and R 3 are the same or different and represent fluorine or a perfluoroalkyl group, since the alkene (halogen atom) represented by general formula ( ^{2 )} , a raw material compound, can be efficiently hydrogenated in the presence of a ^palladium -supported activated carbon catalyst, and the hydrogenated alkene can be produced with high conversion, yield, and/or high selectivity.

The target alkene represented by general formula (1) is preferably 1,1,1,2,4,4,4-heptafluoro-2-butene.

The starting compound, an alkene represented by general formula (1), can be used alone or in combination of two or more types. Commercially available alkenes can also be used.

Preferred Hydrogenation Reaction The hydrogenation reaction step of the present disclosure preferably uses a palladium-supported activated carbon catalyst to hydrogenate perfluoro-2-butene, an alkene raw material compound, to produce 1,1,1,2,4,4,4-heptafluoro-2-butene, an alkene target compound.

After the hydrogenation reaction is complete, purification can be carried out according to standard methods as needed to obtain the desired compound.

(4) Composition containing an alkene In a preferred embodiment, the composition of the present disclosure comprises:
CF3 _- CF=CH- _CF3 (1,1,1,2,4,4,4-heptafluoro-2-butene);
_CF3 -CFH-CFH- _CF3 ; and
Contains _CF3 -CFH-CFH- _CF2H ;

The composition is preferably used as an etching gas, a refrigerant, a heat transfer medium, a deposition gas, a building block for organic synthesis, or a cleaning gas.

The production method of the present disclosure can produce an alkene represented by general formula (1). The alkene may be obtained in the form of a composition containing the target alkene represented by general formula (1) and the starting alkene represented by general formula (2).

The CF ₃ —CFH—CFH—CF ₃ contained in the composition is, for example, an alkane compound derived from the raw material compound perfluoro-2-butene.

The CF ₃ —CFH—CFH—CF ₂ H contained in the composition is, for example, an alkane compound in the 3H form.

In the composition, the content of 1,1,1,2,4,4,4-heptafluoro-2-butene is preferably 80 mol% or more and 99.9 mol% or less, more preferably 90 mol% or more and 99.9 mol% or less, even more preferably 95 mol% or more and 99.9 mol% or less, and particularly preferably 99 mol% or more and 99.9 mol% or less, based on the total amount of the composition being 100 mol%.In the composition, the content of _CF3 -CF=CH- _CF3 is preferably 80 mol% or more, and the contents of CF3 _-CFH -CFH- _CF3 and _CF3 -CFH-CFH- _CF2H are preferably 20 mol% or less, based on the total amount of the composition being 100 mol%.

According to the production method of the present disclosure, 1,1,1,2,4,4,4-heptafluoro-2-butene (hydrogenated alkene) can be obtained with particularly high selectivity, and as a result, it is possible to reduce components other than 1,1,1,2,4,4,4-heptafluoro-2-butene in the composition. Therefore, according to the production method of the present disclosure, purification to obtain 1,1,1,2,4,4,4-heptafluoro-2-butene can be carried out efficiently.

The compositions are preferably used as etching gases, refrigerants, heat transfer media, etc. for forming cutting-edge microstructures in semiconductors, liquid crystals, etc. Alkene-containing compositions are preferably useful in a variety of applications, such as deposition gases, building blocks for organic synthesis, cleaning gases, etc.

Deposition gas is a gas that deposits an etch-resistant polymer layer.

A building block for organic synthesis refers to a substance that can serve as a precursor to a compound with a highly reactive skeleton. When a composition containing 1,1,1,2,4,4,4-heptafluoro-2-butene is reacted with a fluorine-containing organosilicon compound such as _CF3Si ( _CH3 ) ₃ , a fluoroalkyl group such as a _CF3 group can be introduced, converting the compound into a substance that can be used as a cleaning agent or a fluorine-containing pharmaceutical intermediate.

The above describes an embodiment of the present disclosure.

The embodiments of the present disclosure may be modified in form and detail in various ways without departing from the spirit and scope of the claims.

The following examples are provided to explain this disclosure in more detail.

The present disclosure is not limited in any way by these examples.

Example Raw material compound: Perfluoro-2-butene ( _F3C -CF=CF- _CF3 )
Target compound: 1,1,1,2,4,4,4-heptafluoro-2-butene ( _F3C -CF=CH- _CF3 )
((Z/E)-1327myz)
Gas chromatography: Shimadzu Corporation, product name "GC-2014"
NMR: Manufactured by JEOL, product name "400YH"

A stainless steel pipe (outer diameter: 1/2 inch) was used as the reaction tube, and was filled with a palladium-supported activated carbon catalyst. After drying at 200°C for 3 hours under a nitrogen atmosphere, the temperature was raised to 400°C. After raising the temperature to 400°C, the temperature was lowered to the reaction temperature, and hydrogen diluted with nitrogen was passed through, gradually increasing the hydrogen concentration, and finally the catalyst was hydrogenated with 100% hydrogen.

A gas-phase flow reaction was carried out under normal pressure, and the contact time (W/F ₀ ) between perfluoro-2-butene (raw material compound) and palladium-supported activated carbon catalyst (1% Pd/C) was set to 8 g·sec/cc (%), 17 g
The raw material compounds were passed through the reactor so that the flow rates were 38 g·sec/cc (%), 60 g·sec/cc (%), or 78 g·sec/cc (%).

The amount of hydrogen used was such that the H ₂ /alkene molar ratio was 1.1.

( _H2 : 1.1 moles, alkene mole: 1 mole)
The reactor was heated to 200° C., 300° C., or 400° C. to initiate the hydrogenation reaction of fluorine atoms. One hour after the start of the hydrogenation reaction, the distillate that had passed through the detoxification tower was collected.

Mass analysis was then performed using gas chromatography/mass spectrometry (GC/MS), and structural analysis was performed using NMR spectroscopy.

After the reaction was completed, mass spectrometry and structural analysis confirmed that the target compound, 1,1,1,2,4,4,4-heptafluoro-2-butene, had been produced.

The alkane compound CF ₃ -CFH-CFH-CF ₃ and the 3H-alkane compound CF ₃ -CFH-CFH-CF ₂ H were produced from the raw material compound perfluoro-2-butene (F ₃ C-FC=CF-CF ₃ ).

The results for each example are shown in Table 1 below.

In Table 1, the contact time (W/F) refers to the flow rate of the raw material gas, that is, the time during which the catalyst and the raw material gas are in contact with each other.

The results of the Examples (Table 1) show that when perfluoro-2-butene, a raw material compound, is hydrogenated in the presence of a palladium-supported activated carbon catalyst to produce 1,1,1,2,4,4,4-heptafluoro-2-butene as the target compound, the hydrogenation reaction can be carried out efficiently, and the hydrogenated alkene can be produced with a high conversion, yield, and/or high selectivity. The use of a palladium-supported activated carbon catalyst is a particularly preferred embodiment.

Claims (1)

General formula (1):
In formula (1) , ^R1 and ^R3 may be the same or different and represent a trifluoromethyl group or a pentafluoroethyl group .
In formula (1) , ^R2 represents a fluorine atom.
The alkene represented by formula (1) has 5 or 6 carbon atoms.
A method for producing an alkene represented by the formula:
General formula (2):
(In formula (2) , X is a fluorine atom.
In formula (2) , R ¹ and R ³ may be the same or different and represent a trifluoromethyl group or a pentafluoroethyl group .
In formula (2) , ^R2 represents a fluorine atom.
The alkene represented by formula (2) has 5 or 6 carbon atoms.
An alkene represented by
The method includes a step of hydrogenating the olefin in a gas phase in the presence of an activated carbon catalyst carrying a noble metal or a rare metal,
The noble metal or rare metal is at least one noble metal or rare metal selected from the group consisting of palladium (Pd), platinum (Pt), rhodium (Rh), ruthenium (Ru), and manganese (Mn).