JP6881457B2 - Method for producing 1-chloro-2,3,3,3-tetrafluoropropene - Google Patents

Description

The present invention relates to a method for producing 1-chloro-2,3,3,3-tetrafluoropropene.

1-Chloro-2,3,3,3-tetrafluoropropene (CF ₃ CF = CHCl, HCFO-1224yd; hereinafter also referred to as 1224yd) is 3,3-dichloro-1,1,1,2,2. - pentafluoropropane _{(CF 3 -CF 2 -CHCl 2,} HCFC-225ca) and 1,3-dichloro-1,1,2,2,3-pentafluoropropane _{(CClF 2 -CF 2 -CHClF, HCFC} -225cb ), Etc., is a compound that has a small global warming potential (GWP) and has a low impact on the global environment, which is newly useful for cleaning agents, refrigerants, chlorofluorocarbons, solvents, aerosol applications, and the like.

As an example of production of 1224yd, for example, in Patent Document 1, 1,1-dichloro-2,3,3,3-tetrafluoropropene (CF ₃ CF = CCl ₂ , CFO-1214ya; hereinafter, also referred to as 1214ya). _{To obtain 2,3,3,3-tetrafluoropropene (CF 3} CF = CH ₂ , HFO-1234yf) by reacting with hydrogen in the presence of a palladium catalyst to obtain 1224 yd as an intermediate. It is stated that it will be done. In Patent Document 1, 1224yd obtained as an intermediate in the above reaction is used together with 1214ya as a raw material compound for HFO-1234yf.

Although Patent Document 1 describes conditions and means for obtaining HFO-1234yf, which is a target substance, in a high yield in a method for reducing 1214ya by reacting it with hydrogen, 1224yd, which is positioned as a by-product, can be efficiently obtained. There is no description on how to obtain it. That is, in the method of Patent Document 1, 1224yd is also generated to some extent, but for 1224yd, HFO-1234yf, which is a hyperreduced product, and 1,1,1,2-tetrafluoropropane (CF ₃ CHFCH), which is a reduced product thereof, are further produced. ₃ , HFC-254eb), 1,1,1-trifluoropropane (CF ₃ CH ₂ CH ₃ , HFC-263fb), 3,3,3-trifluoropropene (CF ₃ CH = CH ₂ , HFO-1243zf) There is a problem that a large amount of propane is produced as a by-product.

International Publication No. 2011/162341

In the present invention, 1,1-dichloro-2,3,3,3-tetrafluoropropene (CFO-1214ya; hereinafter, also referred to as 1214ya) is reduced to 1-chloro-2,3,3,3-tetra. In the method for obtaining fluoropropene (HCFO-1224yd; hereinafter, also referred to as 1224yd), superreducants 1,1,1-trifluoropropane (HFC-263fb) and 3,3,3-trifluoropropene (HFO). It is an object of the present invention to provide an efficient method for producing 1-chloro-2,3,3,3-tetrafluoropropene with reduced by-products such as −1243 zf).

In the present specification, for halogenated hydrocarbons, the abbreviation of the compound is described in parentheses after the compound name, but in the present specification, the abbreviation is used instead of the compound name as necessary.

1224yd has Z-form and E-form which are geometric isomers depending on the position of the substituent on the double bond. In the present specification, when a compound name or a compound abbreviation is used without particular mention, at least one selected from Z-form and E-form is indicated, and (E) or (E) or ((E) or (E) or ( When Z) is added, it indicates that it is an E-form or a Z-form of each compound. For example, 1224yd (Z) indicates a Z form and 1224yd (E) indicates an E form.

The present invention provides a method for producing 1224 yd having the following constitution.
[1] Supporting a palladium catalyst on which a palladium catalyst having a metal containing palladium and chlorine and having a ratio (Cl / Pd) of the number of moles of chlorine atoms to the number of moles of palladium atoms is 2.0 or more is supported on a carrier. In the presence of a carrier, 1,1-dichloro-2,3,3,3-tetrafluoropropene is reacted with hydrogen in the gas phase to obtain 1-chloro-2,3,3,3-tetrafluoropropene. A method for producing 1-chloro-2,3,3,3-tetrafluoropropene.
[2] The production method according to [1], wherein the ratio (Cl / Pd) of the number of moles of chlorine atoms to the number of moles of palladium atoms is 2.0 to 5.0.
[3] The production method according to [1] or [2], wherein the ratio of the metal other than palladium to 100 parts by mass of palladium in the metal containing palladium is 50 parts by mass or less.
[4] The production method according to any one of [1] to [3], wherein the mass ratio of the metal containing palladium to the carrier is 0.1 to 10% by mass.
[5] The production method according to any one of [1] to [4], wherein the metal containing palladium is a simple substance of palladium.
[6] The production method according to any one of [1] to [5], wherein the carrier is activated carbon.
[7] The production method according to [6], wherein the activated carbon is coconut shell activated carbon.
[8] The ratio of the number of moles of hydrogen to the number of moles of 1,1-dichloro-2,3,3,3-tetrafluoropropene (H ₂ /1214ya) is 1.4 or less, [1] to The production method according to any one of [7].
[9] The production method according to any one of [1] to [8], wherein the reaction temperature for reacting the 1,1-dichloro-2,3,3,3-tetrafluoropropene with hydrogen is 200 ° C. or lower. ..

The production method of the present invention is a method of reducing 1214ya for which a stable production method has been established to obtain 1224yd, which is industrially easy to carry out and can be carried out stably. Further, according to the method for producing 1224yd of the present invention, it is possible to efficiently produce 1224yd having excellent selectivity and reducing by-products such as HFC-263fb and HFO-1243zf which are superreducing agents.

It is a schematic diagram which showed the reaction apparatus used in an Example.

The method for producing 1224yd of the present invention uses a palladium catalyst having a metal containing palladium and chlorine and having a ratio (Cl / Pd) of the number of moles of chlorine atoms to the number of moles of palladium atoms of 2.0 or more as a carrier. presence of a supported thereby palladium catalyst supporting carrier, hydrogen 1214ya in gas phase which comprises reacting (hereinafter, also referred to. as H ₂₎ and.
The reaction between 1214ya and hydrogen according to the method for producing 1224yd of the present invention is represented by the following formula (1).

The 1224yd obtained by the production method of the present invention may be a mixture of Z-form and E-form, may be only Z-form, or may be E-form only. 1224yd has a high proportion of halogen that suppresses flammability, and has a carbon-carbon double bond in the molecule that is easily decomposed by OH radicals in the atmosphere. Therefore, 1224yd has low flammability and is transferred to the ozone layer. The effect is small and the GWP is small. Therefore, it is highly useful as a cleaning agent, a refrigerant, a foaming agent, a solvent, and an aerosol application.

<1214ya>
The method for producing 1224yd of the present invention uses 1214ya as a raw material. 1214ya can be produced by a known method. The method for obtaining 1214ya is not particularly limited, and for example, as shown in the formula (2), it can be produced by a method in which HCFC-225ca is brought into contact with an alkaline aqueous solution to cause a hydrogen fluoride reaction in the presence of a phase transfer catalyst. ..

The HCFC-225ca used in the reaction of the formula (2) can be used in the state of a mixture of dichloropentafluoropropane (HCFC-225) isomers containing HCFC-225ca and its isomers. When the HCFC-225 isomer mixture is used, only HCFC-225ca in the HCFC-225 isomer mixture is selectively defluorinated by the phase transfer catalyst. After the reaction, the obtained 1214ya can be separated and recovered by a known method such as distillation. As the phase transfer catalyst, tetrabutylammonium bromide (TBAB) is preferable.

The HCFC-225 isomer mixture containing HCFC-225ca can be produced, for example, by reacting tetrafluoroethylene and dichlorofluoromethane in the presence of a catalyst such as aluminum chloride. The HCFC-225 isomer mixture obtained by the reaction contains HCFC-225ca and HCFC-225cc as main components, and 2,2-dichloro-1,1,3,3,3-pentafluoropropane (). CHF ₂ CCl ₂ CF ₃ , HCFC-225aa), 2,3-dichloro-1,1,2,3,3-pentafluoropropane (CHF ₂ CClFCClF ₂ , HCFC-225bb) and the like are contained in a small amount.

As the HCFC-225 isomer mixture containing HCFC-225ca, a commercially available product may be used. Examples of commercially available products include Asahiclean AK225 (manufactured by Asahi Glass Co., Ltd., trade name, a mixture of 48 mol% of HCFC-225ca and 52 mol% of HCFC-225cc).

<Palladium catalyst-supported carrier>
In the production method of the present invention, 1214ya and hydrogen obtained by the above method or the like have a metal containing palladium and chlorine, and the ratio of the number of moles of chlorine atom to the number of moles of palladium atom (Cl / Pd) is The reaction is carried out in the gas phase in the presence of a palladium catalyst-supporting carrier on which a palladium catalyst of 2.0 or more is supported. In the present specification, palladium having a metal containing palladium and chlorine and having a palladium catalyst on which the ratio of the number of moles of chlorine atoms (Cl / Pd) to the number of moles of palladium atoms (Cl / Pd) is 2.0 or more is supported on a carrier. The catalyst-supporting carrier is also referred to as "palladium catalyst-supporting carrier (X)". The palladium catalyst is also referred to as "Pd catalyst".

In the present invention, by carrying out the reaction of the above formula (1) in the presence of the palladium catalyst-supporting carrier (X), by-products such as HFC-263fb and HFO-1243zf, which are superreducing agents, are reduced, and the selectivity is increased. It enables excellent and efficient production of 1224 yd.

In the present invention, the palladium catalyst in the palladium catalyst-supporting carrier (X) has a metal containing palladium and chlorine, and the ratio of the number of moles of chlorine atoms to the number of moles of palladium atoms (Cl / Pd) is 2.0 or more. Is a catalyst. Hereinafter, the metal containing palladium is also referred to as a metal (M). The metal (M) may consist only of palladium, or may contain a metal other than palladium (hereinafter, also referred to as “other metal”). The metal (M) is mainly composed of palladium, and specifically, the ratio of other metals to 100 parts by mass of palladium in the metal (M) is preferably 50 parts by mass or less from the viewpoint of reducing by-products. The ratio of other metals to 100 parts by mass of palladium is preferably 30 parts by mass or less, more preferably 10 parts by mass or less, from the viewpoint of reducing by-products. The metal (M) does not contain a metal other than palladium, that is, it is particularly preferable that the metal (M) is palladium alone in that high catalytic activity can be obtained.

Other metals include Group 8 elements such as iron, ruthenium and osmium; Group 9 elements such as cobalt, rhodium and iridium; Group 10 elements such as nickel and platinum; Group 11 elements such as gold, silver and copper. Elements; examples include ruthenium, zinc, cadmium, tin, lead, antimony, bismus and the like. These other metals may be one kind or two or more kinds. The metal (M) may be an alloy of palladium and other metals, that is, a palladium alloy, or may be a mixture of palladium and other metals. Examples of the palladium alloy include a palladium / platinum alloy and a palladium / rhodium alloy. When a metal (M) containing another metal in addition to palladium is used, the catalyst durability is higher than when a metal (M) composed of palladium alone is used.

The palladium catalyst in the palladium catalyst-supporting carrier (X) has a metal containing palladium and chlorine, and the ratio of the number of moles of chlorine atoms to the number of moles of palladium atoms (Cl / Pd) is 2.0 or more. The Cl / Pd of the palladium catalyst is preferably 2.0 to 10.0, more preferably 2.0 to 5.0, from the viewpoint of further increasing the selectivity of 1224yd.

In the present specification, Cl / Pd of the palladium catalyst in the palladium catalyst-supported carrier (X) is calculated by the following method based on the type of the carrier and the hydrogen chloride treatment for obtaining the carrier. _{In the calculation, a palladium-supported carrier (Y 0} ) in which 0.5% by mass of palladium was supported on the surface of silicon dioxide was treated with a predetermined amount of hydrogen chloride to support a palladium catalyst on which a palladium catalyst having palladium and chlorine was supported. The carrier (Y) is used as a standard.

[Calculation method of Cl / Pd]
_{(I) A palladium-supported carrier (Y 0} ) in which 0.5% by mass of palladium is supported on the surface of silicon dioxide and silicon dioxide are prepared.
(Ii) 70 g of a palladium-supported carrier (Y ₀ ) is weighed, filled in a U-shaped tube made of SUS314 with an inner diameter of 21.4 cm, and hydrogen chloride gas is allowed to flow at 45 ° C. and a gas flow rate of 300 mL / min for 120 minutes. Next, nitrogen gas is passed through the U-shaped tube at 45 ° C. and a gas flow rate of 300 mL / min for 30 minutes to perform vacuum drying. A palladium catalyst-supporting carrier (Y) on which a palladium catalyst having palladium and chlorine obtained by the above treatment was carried was recovered from the U-shaped tube, and the content of chlorine atoms on the surface thereof (atom%; in formula (3)). (A) and the content of palladium atoms (atom%; “e” in formula (3)) are determined by X-ray photoelectron spectroscopy (XPS) wide spectrum measurement.
(Iii) After weighing 70 g of silicon dioxide and performing the same treatment as in (ii) above, the chlorine atom content (atom%; “b” in the formula (3)) on the surface thereof is set to X. Obtained by X-ray photoelectron spectroscopy (XPS) wide spectrum measurement.

From the values measured in (ii) and (iii) above, Cl / Pd of the palladium catalyst-supporting carrier (Y) is represented by [Cl / Pd] _(y) in the following formula (3). ).
[Cl / Pd] _(y) = (ab) / e equation (3)
a: Cl content (atom%) on the surface of the palladium catalyst-supporting carrier (Y) obtained from the XPS wide spectrum.
b: Cl content (atom%) on the surface of silicon dioxide obtained from the XPS wide spectrum.
e: Pd content (atom%) on the surface of the palladium catalyst-supported carrier (Y) obtained from the XPS wide spectrum.

The Cl / Pd of the palladium catalyst-supporting carrier (X) ( _{indicated by [Cl / Pd] (x)} in the formula (4)) is the above-mentioned [Cl / Pd] _{(y) in addition} to the palladium catalyst-supporting carrier (X). It is calculated by the following formula (4) by multiplying the palladium-supported amount correction coefficient given by the type of carrier used in (X) and the correction coefficient based on the hydrogen chloride treatment amount at the time of producing the palladium catalyst-supported carrier (X).
[Cl / Pd] _(x) = [Cl / Pd] _(y) × c × d equation (4)

c: Hydrogen chloride treatment amount correction coefficient c is based on the hydrogen chloride treatment amount (300 mL / min, 120 minutes) per unit mass when producing the palladium catalyst-supporting carrier (Y), and the palladium catalyst-supporting carrier (X). It is a value obtained by dividing the amount of hydrogen chloride processed per unit mass when the above-mentioned standard is used.

d: Palladium-supported amount correction coefficient d is a coefficient given by the difference between the palladium-supported carrier (Y) and the palladium-supported carrier (X). For example, when the carrier of the palladium catalyst-supporting carrier (X) is coconut shell activated carbon, the coconut shell activated carbon can support palladium 1.4 times by mass with respect to silicon dioxide which is the carrier of the palladium catalyst-supporting carrier (Y). , The correction coefficient d is 1.4.

In the palladium catalyst-supported carrier (X), when the metal (M) supported on the carrier is composed of palladium and other metals, the above-mentioned d is a numerical value obtained by multiplying the content ratio of palladium with respect to the metal (M) by the formula (4). ).

In the production method of the present invention, the palladium catalyst is used as the palladium catalyst-supported carrier (X) supported on the carrier. Examples of the carrier include activated carbon and metal oxides such as alumina, zirconia, silica, and titania. Of these, activated carbon is preferable from the viewpoint of catalytic activity, durability, and reaction selectivity.

Examples of the activated carbon include those prepared from wood, charcoal, fruit husks, coconut shells, peat, lignite, coal and the like as raw materials, and those obtained from plant raw materials are preferable to mineral raw materials, and coconut shell activated carbon is particularly preferable. preferable. Examples of the shape of the activated carbon include briquette having a length of about 2 to 5 mm, crushed charcoal having a length of about 4 to 50 mesh, and granular charcoal. Of these, 4 to 20 mesh crushed coal or briquette is preferable.

The amount of the palladium catalyst supported on the palladium catalyst-supported carrier (X) is preferably 0.1 to 10% by mass, more preferably 0.5 to 1% by mass, based on the amount of the metal (M). When the amount of the palladium catalyst supported is equal to or greater than the lower limit, the reaction rate between 1214ya and hydrogen is improved. When the amount of the palladium catalyst supported is not more than the upper limit value, it is easy to suppress an excessive temperature rise of the catalyst layer (described later) due to the heat of reaction, and it is easy to reduce the formation of by-products.

Specifically, the palladium catalyst-supporting carrier (X) is a metal (M)-supporting carrier on which a metal (M) is supported, and Cl / Pd in the obtained palladium catalyst-supporting carrier (X) is within the above-mentioned predetermined range. It can be prepared by treating with hydrogen chloride gas as described above. As a method of supporting the metal (M) on the carrier, generally, a method of supporting the metal catalyst on the carrier can be used without particular limitation. For example, when palladium alone is metal (M) and the carrier is activated carbon, the activated carbon is impregnated with an aqueous solution of palladium salts such as palladium (II) chloride, palladium (II) nitrate, and tetraamine palladium (II) chloride, and dried. As a result, after precipitating the palladium salt on the surface of the activated carbon, the palladium ions in the palladium salt are reduced with hydrogen gas to obtain the palladium-supported activated carbon.

The hydrogen chloride gas treatment for obtaining the palladium catalyst-supported carrier (X) from the metal (M) -supported carrier can be performed, for example, under heating. Specifically, a reactor similar to that used in the production of 1224 yd is filled with a metal (M) -supported carrier, and hydrogen chloride gas is supplied to the reactor while adjusting the temperature of the reactor in an oil bath or the like. Can prepare a palladium catalyst-supported carrier (X). The heating temperature is preferably 10 to 80 ° C. as the temperature of the oil bath or the like. The treatment time in this case depends on the filling amount of the metal (M) -supported carrier in the reactor, the flow rate of hydrogen chloride gas, the temperature of the oil bath, etc. A palladium catalyst-supporting carrier (X) adjusted to the above range is obtained.

When the palladium catalyst-supported carrier (X) is produced using the reactor in this way, the reactor filled with the palladium catalyst-supported carrier (X) can be used as it is for the production of the following 1224 yd. ..

<Manufacturing of 1224yd>
In the production method of the present invention, as a method of reacting 1214ya with hydrogen in the gas phase in the presence of the palladium catalyst-supporting carrier (X), specifically, a catalyst layer filled with the palladium catalyst-supporting carrier (X) is formed. , A method of introducing 1214ya and hydrogen into the catalyst layer in the form of a gas can be mentioned.

In the present invention, the catalyst layer is usually formed by filling the reactor with a palladium catalyst-supporting carrier (X). The packing density of the palladium catalyst-loaded support (X) in the catalyst layer is preferably ^{0.3~1g / cm 3, 0.4~0.8g / cm} 3 is more preferable. When the packing density of the palladium catalyst-supporting carrier (X) is equal to or higher than the lower limit, the filling amount of the palladium catalyst-supporting carrier (X) per unit volume is large, and the amount of gas to be reacted can be increased, so that the productivity is improved. To do. When the packing density of the palladium catalyst-supporting carrier (X) is not more than the upper limit value, it is easy to suppress an excessive temperature rise of the catalyst layer due to the heat of reaction, and it is easy to reduce the formation of by-products. The packed portion of the palladium catalyst-supporting carrier (X), that is, the catalyst layer may be one in the reactor or two or more.

In order to carry out the production method of the present invention using such a catalyst layer, gaseous 1214ya and hydrogen are introduced from one side of the catalyst layer. The introduced 1214ya and hydrogen gas react in the gas phase while passing through the catalyst layer to produce 1224yd. Then, 1214ya of the catalyst layer and the generated gas containing 1224yd are discharged from the side opposite to the side into which hydrogen is introduced. Hereinafter, the production method of the present invention will be described by taking the case of using the catalyst layer as an example. The side of the catalyst layer where 1214ya and hydrogen are introduced is called the "gas introduction section", and the side where the generated gas is discharged is called the "gas discharge section".

The ratio of 1214ya to hydrogen introduced into the catalyst layer is the ratio of the number of moles of 1214ya to the number of moles of hydrogen (H ₂ /) from the viewpoint of reducing by-products such as HFC-263fb and HFO-1243zf, which are superreducers. It is preferably represented by 1214ya) and its value is preferably 1.4 or less. 1214ya the molar ratio of hydrogen _(H 2 / 1214ya) is smaller HFC-263fb, easy to reduce the by-production of such HFO-1243zf, and more preferably 1.2 or less, more preferably 1.0 or less. The molar ratio (H ₂ /1214ya) is preferably 0.2 or more, more preferably 0.4 or more, and most preferably 0.5 or more, from the viewpoint of the yield of 1224 yd. Molar ratio _(H 2 / 1214ya) is, HFC-263fb, and the viewpoint of reducing by-product such as HFO-1243zf, in terms of 1224yd yield is preferably 0.2 to 1.4, 0.4 or higher 1.2 or less is more preferable, and 0.5 or more and 1.0 or less is most preferable.

Similarly, when hydrogen is introduced separately as in the method (A) described later, the ratio of 1214ya introduced into the catalyst layer to the total amount of hydrogen introduced into the catalyst layer is 1214ya and the molar ratio of hydrogen (H ₂ /1214ya). ) Is preferably 1.4 or less, more preferably 1.2 or less, and even more preferably 1.0 or less. The molar ratio of 1214ya to hydrogen (H ₂ /1214ya) is preferably 0.2 or more, more preferably 0.4 or more, and most preferably 0.5 or more. From the same viewpoint, the molar ratio of 1214ya to hydrogen (H ₂ /1214ya) is preferably 0.2 or more and 1.4 or less, more preferably 0.4 or more and 1.2 or less, and 0.5 or more and 1.0 or less. Most preferred.

In the production method of the present invention, the reaction temperature for reacting 1214ya with hydrogen is a gas phase reaction. Therefore, a mixed gas of 1214ya and hydrogen used for the reaction, but when an inert gas is used, 1214ya and hydrogen are not present. The temperature shall exceed the dew point of the mixed gas of the active gas. Further, in the production method of the present invention, the reaction temperature is preferably 200 ° C. or lower, more preferably 190 ° C. or lower, and particularly preferably 150 to 190 ° C. from the viewpoint of suppressing the formation of by-products.

Specifically, the reaction temperature in the production method of the present invention is indicated by the temperature in the reaction region of the catalyst layer described below. In the production method of the present invention, by controlling the temperature of the reaction region of the catalyst layer, that is, the maximum temperature of the catalyst layer within the above reaction temperature range, it is possible to improve the reactivity and suppress the production of by-products.

Even if the initial temperature is set to a predetermined temperature, the temperature of the catalyst layer gradually decreases as the deterioration of the catalyst progresses, and there is a problem that the reaction rate decreases. Therefore, it is preferable to perform an operation of keeping the temperature of the catalyst layer at a predetermined temperature so that a high reaction rate can be maintained. For example, when the catalyst layer is heated from the outside with a heat medium or the like to maintain the temperature, the temperature of the catalyst layer can be prevented from decreasing by gradually increasing the temperature of the heat medium. The temperature of the heat medium is preferably 40 to 100 ° C, more preferably 80 to 100 ° C. As the heat medium, perfluoroether, nitrate, silicone oil, water and the like are preferable, and perfluoroether or water is more preferable.

The temperature of the catalyst layer means the temperature of the catalyst layer maintained by heating from the outside or the like. Normally, 1214ya and hydrogen react in a part of the catalyst layer, and the reaction region (the region where 1214ya and hydrogen are reacting) becomes hotter than the other catalyst layer regions due to the generation of heat of reaction. As the catalytic activity of this reaction region decreases with time, the reaction region usually gradually moves from the vicinity of the gas introduction portion to the downstream side in the gas flow direction. Further, on the downstream side of the reaction region, the generated gas having a high temperature generated in the reaction region flows, and the temperature is usually higher than the temperature of the catalyst layer, and the temperature gradually decreases as the distance from the reaction region increases. In the present invention, the temperature of the catalyst layer means the temperature on the upstream side of the reaction region, that is, the temperature of the catalyst layer that is heated from the outside with a heat medium or the like to maintain the temperature.

Further, in the production method of the present invention, it is preferable to suppress an excessive temperature rise of the catalyst layer due to the reaction heat of 1214ya and hydrogen so that the maximum temperature of the catalyst layer is equal to or lower than the upper limit of the reaction temperature. As described above, the temperature in the reaction region where 1214ya and hydrogen are reacting and the region on the downstream side thereof becomes higher than the temperature of the catalyst layer in the other regions due to the heat of reaction. The maximum temperature of the catalyst layer during the reaction means the maximum temperature of the catalyst layer region which is higher than other regions due to the generation of this heat of reaction. Examples of the method for measuring the maximum temperature of the catalyst layer during the reaction include the following measurement method using an insertion type thermometer.

In the reaction between 1214ya and hydrogen in the catalyst layer, first, the catalyst near the gas introduction part, which is introduced in the form of gas, contributes to the reaction, and when the catalyst near the gas introduction part deteriorates, the catalyst on the downstream side reacts. The reaction region in the catalyst layer gradually moves toward the gas discharge side so as to contribute. That is, since the portion showing the maximum temperature of the catalyst layer moves with the movement of the reaction region of 1214ya and hydrogen, the measurement unit of the insertion type thermometer is previously positioned at the gas introduction portion of the catalyst layer. The maximum temperature of the catalyst layer can be measured by moving the measuring unit as the reaction progresses.

As a method of maintaining the maximum temperature of the catalyst layer during the reaction below the upper limit of the reaction temperature, hydrogen is divided into the catalyst layers from the viewpoint of easily maintaining high productivity while controlling the maximum temperature of the catalyst layer to be low. (Method (A)) is preferable. If hydrogen is introduced by dividing it into a plurality of locations in the catalyst layer, the reaction region of the catalyst layer can be dispersed without changing the amount of 1214ya introduced, so that the heat of reaction is not concentrated in one location. Therefore, local excessive heat generation of the catalyst layer can be easily suppressed without lowering the productivity.

The split introduction of hydrogen means that 1214ya and hydrogen are introduced into the gas introduction part of the catalyst layer, and hydrogen is introduced from at least one place between the gas introduction part and the gas discharge part of the catalyst layer. That is, it means that hydrogen is introduced from at least one place of the catalyst layer, that is, two or more places in total, other than the gas introduction part.

Specifically, the amount of 1214ya and hydrogen introduced into the gas introduction part of the catalyst layer (located on the most upstream side in the gas flow direction in the catalyst layer) is a part of hydrogen introduced into the catalyst layer and the total amount of 1214ya. And. Residual hydrogen is introduced into the catalyst layer downstream in the gas flow direction from the hydrogen introduction part, and hydrogen is introduced into the gas flowing through the catalyst layer at the introduction position (usually, the generated gas after a part of 1214ya reacts with hydrogen). Is mixed, and unreacted 1214ya is reacted with hydrogen in the catalyst layer on the downstream side from the hydrogen introduction position, and is generated from the gas discharge part of the catalyst layer (located on the most downstream side in the gas flow direction in the catalyst layer). Discharge gas.

It is preferable that at least a part of the hydrogen introduced from the gas introduction section reacts with 1214ya between the gas introduction section and the hydrogen introduction section on the most upstream side in the gas flow direction. Further, the hydrogen introduction section on the most downstream side in the gas flow direction is a catalyst layer between the hydrogen introduction section and the gas discharge section, and is a position where hydrogen introduced from the hydrogen introduction section and 1214ya can sufficiently react with each other. It is preferable to provide in.

Hydrogen may be introduced in two places or divided into three or more places in the method (A), and it is preferable to introduce hydrogen in two places from the viewpoint of simplifying the process. It is preferable that the amount of each hydrogen divided and introduced into the catalyst layer is equal because it is easy to keep the maximum temperature of the catalyst layer low.

When there are two or more catalyst layers in the reactor, the split introduction of hydrogen, for example, introduces a part of hydrogen together with 1214ya into the most upstream (first stage) catalyst layer, and the rest downstream from the first stage. A method of introducing into the catalyst layer of the second and subsequent stages on the side can be mentioned.

Further, as a method for controlling the maximum temperature of the catalyst layer other than the method (A), a method (method (B)) in which the inert gas is circulated through the catalyst layer together with 1214ya and hydrogen can be mentioned. By allowing the inert gas to flow and adjusting the concentrations of 1214ya and hydrogen flowing in the catalyst layer, it is possible to suppress an excessive temperature rise of the catalyst layer due to the heat of reaction. Further, a diluting gas other than the inert gas can be used instead of the inert gas or together with the inert gas.

Examples of the inert gas include nitrogen, noble gases (helium, argon, etc.), carbon dioxide, chlorofluorocarbons that are inert to the hydrogenation reaction, and the like.

The amount of the inert gas introduced into the catalyst layer is based on 1 mol of 1214ya because it is easy to keep the maximum temperature of the catalyst layer low, it is easy to reduce the formation of by-products, and it is easy to suppress the deterioration of the catalyst. Therefore, 0.5 mol or more is preferable, and 1.0 mol or more is more preferable. The amount of the inert gas introduced is preferably 10.0 mol or less, more preferably 4.0 mol or less, relative to 1 mol of 1214ya, from the viewpoint of the recovery rate of the inert gas. From the viewpoint of easily reducing the production of by-products, easily suppressing the deterioration of the catalyst, and the recovery rate of the inert gas, 0.5 mol or more and 10.0 mol or less is preferable with respect to 1 mol of 1214ya. , 1.0 mol or more and 4.0 mol or less is more preferable.

Further, as a method for controlling the maximum temperature of the catalyst layer other than the method (A) and the method (B), the temperature of the catalyst layer is set to a lower temperature with the dew point of the mixed gas of 1214ya and hydrogen used in the reaction as the lower limit. A method (method (C)) can be mentioned. When an inert gas is used, the temperature is set lower with the dew point of the mixed gas of 1214ya, hydrogen and the inert gas as the lower limit. By keeping the temperature of the catalyst layer low, the heat of reaction can be removed more quickly, and an excessive temperature rise of the catalyst layer can be suppressed.

In the method (C), the lower the temperature of the catalyst layer, the more advantageous it is to suppress the formation of by-products that are difficult to separate from the target 1224yd, and in the reaction in the liquefied state of the raw material, The temperature of the catalyst layer is preferably higher than the dew point of the mixed gas, because the yield of 1224 yd decreases due to the increase in the production of by-products in which 1224 yd is excessively reduced. More preferably, it is higher than the dew point and less than 50 ° C., and more preferably, it is higher than the dew point and less than 30 ° C.

For controlling the maximum temperature of the catalyst layer, it is preferable to use the method (A), the method (B), and the method (C) individually, or to use two or three of them in combination.

The reaction pressure is preferably normal pressure from the viewpoint of handleability. The reaction time is preferably 0.4 to 400 seconds, more preferably 1 to 400 seconds, and most preferably 4 to 400 seconds. In the production method of the present invention, the reaction time is specifically the contact time of 1214ya with the palladium catalyst-supported carrier (X). This contact time is calculated from the volume of 1214ya introduced into the reactor and the volume of the catalyst layer.

In the production method of the present invention, the linear velocity u of 1214ya represented by the following formula (5) in the catalyst layer is preferably 0.1 to 100 cm / sec, more preferably 0.1 to 30 cm / sec, and 0.1. Most preferably 10 cm / sec. When the linear velocity u is 0.1 cm / sec or more, the productivity is improved and 1214ya easily flows uniformly through the catalyst layer. When the linear velocity u is 100 cm / sec or less, the reaction rate of 1214ya and hydrogen is improved, and when the linear velocity u is 30 cm / sec or less, the temperature control near the reaction point by heat generation becomes easy.

The linear velocity u is calculated by the following equation (5) from the amount of gas of 1214ya introduced into the reactor and the volume of the catalyst layer.
u = (W / 100) × V / S-expression (5)
W: Concentration (mol%) of 1214ya in the total gas flowing through the catalyst layer
V: Flow rate of all gas flowing through the catalyst layer (cm ³ / sec)
S: Cross-sectional area of the catalyst layer with respect to the gas flow direction (cm ² )

In the production method of the present invention, the gaseous components introduced into the catalyst layer include 1214ya, hydrogen, an inert gas as an optional component, a diluting gas, and other components as long as the effects of the present invention are not impaired. It may be included. Examples of other components include components that are brought in together with 1214ya as impurities when preparing 1214ya.

Examples of the reactor used in the production method of the present invention include known reactors capable of forming a catalyst layer by filling with a catalyst-supporting carrier. Examples of the material of the reactor include glass, iron, nickel, and alloys containing these as main components.

In addition to the target product, 1224yd, the produced gas after the reaction includes unreacted raw materials, superreducants such as HFO-1234yf, HFC-254eb, HFC-263fb, HFO-1243zf, and hydrogen chloride (HCl). included.

HCl contained in the product gas can be removed, for example, by blowing the product gas into an alkaline aqueous solution to neutralize it. Examples of the alkali used in the alkaline aqueous solution include sodium hydroxide and potassium hydroxide. The amount of HCl contained in the produced gas is small and does not particularly affect Cl / Pd of the palladium catalyst-supporting carrier. As a method for recovering 1224 yd from the produced gas, for example, a known method such as fractional distillation can be adopted. The resulting 1224 yd is usually a mixture of 1224 yd E and Z isomers. When it is necessary to separate 1224 yd E-form and Z-form from the mixture, a separation and purification method such as distillation may be used.

According to the production method of the present invention described above, a palladium catalyst having a metal containing palladium and chlorine, and the ratio (Cl / Pd) of the number of moles of chlorine atoms to the number of moles of palladium atoms is 2.0 or more. By reacting 1214ya with hydrogen in the gas phase in the presence of a palladium-catalyzed carrier supporting the above, by-products such as HFO-1234yf, HFC-254eb, HFC-263fb, and HFO-1243zf, which are hyperreducators. Is reduced. According to the production method of the present invention, the effect of suppressing the by-production of HFC-263fb and HFO-1243zf is particularly remarkable. In this way, the production of by-products is suppressed, and as a result, the amount of the target product, 1224 yd, in the produced gas is increased, so that efficient production of 1224 yd with excellent selectivity is possible. Further, since 1214ya used in the reaction is a compound for which a stable production method has been established from easily available raw materials, the production method of the present invention is industrially easy to carry out and can be stably carried out. I can say.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the following description. Examples 1 to 4 are Examples, and Examples 5 to 6 are Comparative Examples.

First, the palladium catalyst-supporting carrier used in each example was prepared as follows. The palladium catalyst-supporting carriers (X1) and (X2) are the palladium catalyst-supporting carriers according to the present invention, and the palladium catalyst-supporting carrier (Cf1) is a palladium catalyst-supporting carrier for comparative examples. Further, for the preparation of each palladium catalyst-supporting carrier, a palladium-supporting activated carbon (manufactured by NE-Echemcat Co., Ltd.) in which 0.5% by mass of palladium alone is supported with respect to 100% by mass of coconut shell activated carbon having a particle size of 4 to 8 mesh (Hereinafter referred to as "palladium-supported activated carbon (A)") was used.

Further, in order to calculate Cl / Pd of the palladium catalyst-supporting carrier, the above measurements (ii) and (iii) were carried out, and [Cl / Pd] _(y) was obtained by the formula (3). [Cl / Pd] Cl / Pd of each palladium catalyst-supporting carrier was calculated by the formula (4) from the carrier, hydrogen chloride treatment conditions, etc. in _{(y) and each palladium catalyst-supporting carrier.}

When Cl / Pd in the palladium-supported activated carbon (A) is calculated by the above calculation method, Cl / Pd is 0.0 because it has not been subjected to hydrogen chloride treatment. The palladium-supported activated carbon (A) was used as a palladium catalyst-supported carrier (Cf1).

[Preparation Example 1]
Palladium-supported activated carbon (A) was filled in the reaction tube of the same apparatus as the following reactor. While maintaining the temperature of the oil bath in which the reaction tube was immersed at 45 ° C., hydrogen chloride was circulated through the palladium-supported activated carbon (A) at a flow rate of 300 mL / sec for 2 hours to obtain a palladium-supported carrier (X1). Obtained. The Cl / Pd of the palladium catalyst in the obtained palladium catalyst-supporting carrier (X1) was calculated by the above calculation method and found to be 2.2.

[Preparation Example 2]
A palladium catalyst-supported carrier (X2) was obtained in the same manner as in Preparation Example 1 except that the hydrogen chloride treatment time in Preparation Example 1 was changed from 2 hours to 8 hours. The Cl / Pd of the palladium catalyst in the obtained palladium catalyst-supporting carrier (X2) was calculated by the above calculation method and found to be 4.6.

[Example 1]
For the production of 1224yd, the reactor 100 shown in the schematic diagram in FIG. 1 was used. As shown in FIG. 1, the reaction apparatus 100 includes one reaction tube 8 and an oil bath 9 in which the reaction tube 8 is immersed. As the reaction tube 8, a U-shaped reaction tube made of SUS304 having an inner diameter of 2.14 cm and a total length of 70 cm was used. The reaction tube 8 is a catalyst having a height of 40 cm, wherein the outlet 11 side thereof is filled with the palladium catalyst-supporting carrier (X1) (Cl / Pd = 2.2) prepared above at a packing density of 0.73 g / cm ^3. It has a layer 10. ^{Perfluoroether FOMBLIN (R)} YLVAC (Solvay) was used as the heat medium used in the oil bath.

Further, the reaction device 100 has a 1214ya gas storage container 1, a hydrogen gas storage container 2, and a nitrogen gas storage container 3, and each container is connected to the inlet 7 of the reaction tube 8 via pipes 4, 5, and 6, respectively. ing. The gas discharged from the outlet 11 of the reaction tube 8 is transferred to the alkaline cleaning tank 14 by the pipe 13, and after the alkaline cleaning, is recovered in the generated gas storage container 16 via the pipe 15. In the following description, the gas discharged from the outlet 11 of the reaction tube 8 is referred to as “outlet gas”, and the gas obtained by alkaline cleaning the outlet gas is referred to as “produced gas”.

First, the reaction tube 8 was immersed in an oil bath 9 whose temperature was adjusted to 45 ° C. so that the catalyst layer 10 was completely immersed, and the catalyst layer 10 was heated to 45 ° C. Next, 1214ya gas, hydrogen gas, and nitrogen gas were circulated through the reaction tube 8, and the discharged outlet gas was alkaline-washed to obtain a produced gas.

The contact time of 1214ya gas with the palladium catalyst-supporting carrier (X1) filled in the catalyst layer 10 was 12 seconds, and the ratio of the number of moles of 1214ya gas to the total number of moles of hydrogen gas introduced into the catalyst layer ( H ₂ / 1214ya) was 1.0. Further, the number of moles of 1214ya gas, the ratio of the moles of the total introduced amount of the nitrogen gas to be introduced into the catalyst layer _(N 2 / 1214ya) was 2.0. The linear velocity u of 1214ya was set to 0.8 cm / sec.

Further, the maximum temperature (reaction temperature) of the catalyst layer 10 during the reaction was measured by a plug-in type thermometer 12 inserted into the catalyst layer and found to be 171 ° C. Alkaline cleaning of the outlet gas was performed with a 20 mass% sodium hydroxide aqueous solution at a temperature of 15 ° C.

[Example 2]
A product gas was obtained in the same manner as in Example 1 except that the temperature of the oil bath 9 was changed to 80 ° C. The maximum temperature of the catalyst layer 10 during the reaction was measured by a plug-in type thermometer 12 inserted into the catalyst layer and found to be 183 ° C.

[Example 3]
A product gas was obtained in the same manner as in Example 1 except that the palladium catalyst-supported carrier (X1) (Cl / Pd = 2.2) was changed to the palladium catalyst-supported carrier (X2) (Cl / Pd = 4.6). .. The maximum temperature of the catalyst layer 10 during the reaction was measured by a plug-in type thermometer 12 inserted into the catalyst layer and found to be 153 ° C.

[Example 4]
A product gas was obtained in the same manner as in Example 3 except that the temperature of the oil bath 9 was changed to 80 ° C. The maximum temperature of the catalyst layer 10 during the reaction was measured by a plug-in type thermometer 12 inserted into the catalyst layer and found to be 171 ° C.

[Example 5]
A product gas was obtained in the same manner as in Example 1 except that the palladium catalyst-supported carrier (X1) (Cl / Pd = 2.2) was changed to the palladium catalyst-supported carrier (Cf1) (Cl / Pd = 0.0). .. The maximum temperature of the catalyst layer 10 during the reaction was measured by a plug-in type thermometer 12 inserted into the catalyst layer and found to be 153 ° C.

[Example 6]
A product gas was obtained in the same manner as in Example 5 except that the temperature of the oil bath 9 was changed to 80 ° C. The maximum temperature of the catalyst layer 10 during the reaction was measured by a plug-in type thermometer 12 inserted into the catalyst layer and found to be 171 ° C.

[Analysis method]
The produced gas obtained in each example was analyzed by gas chromatography (GC), and the selectivity X (unit:%) of 1214ya to 1224yd (Z) and 1224yd by the following formulas (6) and (7). The selectivity Y (unit:%) for (E) was calculated respectively.

X = [a / (a + b + c)] × 100 Equation (6)
Y = [b / (a + b + c)] × 100 Equation (7)
(However, in the formulas (6) and (7), "a" is the number of moles of 1224yd (Z), "b" is the number of moles of 1224yd (E), and "c" is the superreduced substance (HFO-1234yf, HFC-). 254eb, HFC-263fb, HFO-1243zf, etc.) The total number of moles is shown.)

Further, the yield of 1224yd (Z-form and E-form) was calculated by the following formula (8).
Yield of 1224yd (Z-form and E-form) = [A × (X + Y)] / 100 formula (8)
(However, in formula (8), "A" indicates a reaction rate of 1214ya.)

The analysis results are shown in Table 1 together with the reaction conditions and the like. Table 2 shows the area ratio of the produced gas in the GC analysis as a molar ratio (unit: mol%). The types of palladium catalyst-supporting carriers in Table 1 indicate only the reference numerals.

As shown in Tables 1 and 2, in Examples 1 to 4 of Examples of the present invention, the ratio of the number of moles of chlorine atoms (Cl / Pd) to the number of moles of palladium atoms of the palladium catalyst in the palladium catalyst-supporting carrier is Higher results were obtained for the sum of the selectivity X for 1224yd (Z) and the selectivity Y for 1224yd (E), and the yield of 1224yd, as compared to Examples 5-6, which are outside the scope of the present invention. Further, in Examples 1 to 4, the by-products of the hyperreducants HFC-263fb and HFO-1243zf were remarkably suppressed.

According to the production method of the present invention, in the method of reducing 1214ya to obtain 1224yd, high-purity 1224yd can be produced by suppressing the production of reduced products such as HFC-263fb and HFO-1243zf. The 1224yd obtained by the method of the present invention has a small global warming potential (GWP) and is useful as a compound alternative to chlorofluorocarbons in detergents, refrigerants, foaming agents, solvents, aerosol applications and the like.

100 ... Reaction device, 1 ... 1214ya gas storage container, 2 ... Hydrogen gas storage container, 3 ... Nitrogen gas storage container, 7 ... Reaction tube inlet, 8 ... Reaction tube, 9 ... Oil bath, 10 ... Catalyst layer, 11 ... Reaction Tube outlet, 12 ... thermometer, 14 ... alkaline cleaning tank, 16 ... generated gas storage container.

Claims (9)

Presence of a palladium catalyst-supporting carrier on which a palladium catalyst having a metal containing palladium and chlorine and having a ratio (Cl / Pd) of the number of moles of chlorine atoms to the number of moles of palladium atoms is 2.0 or more is supported on the carrier. Below, in the gas phase, 1,1-dichloro-2,3,3,3-tetrafluoropropene is reacted with hydrogen to obtain 1-chloro-2,3,3,3-tetrafluoropropene. A method for producing 1-chloro-2,3,3,3-tetrafluoropropene. The production method according to claim 1, wherein the ratio (Cl / Pd) of the number of moles of chlorine atoms to the number of moles of palladium atoms is 2.0 to 5.0. The production method according to claim 1 or 2, wherein the ratio of the metal other than palladium to 100 parts by mass of palladium in the metal containing palladium is 50 parts by mass or less. The production method according to any one of claims 1 to 3, wherein the mass ratio of the metal containing palladium to the carrier is 0.1 to 10% by mass. The production method according to any one of claims 1 to 4, wherein the metal containing palladium is a simple substance of palladium. The production method according to any one of claims 1 to 5, wherein the carrier is activated carbon. The production method according to claim 6, wherein the activated carbon is coconut shell activated carbon. Any of claims 1 to 7, wherein the ratio of the number of moles of hydrogen to the number of moles of 1,1-dichloro-2,3,3,3-tetrafluoropropene (H ₂ /1214ya) is 1.4 or less. The manufacturing method according to one item. The production method according to any one of claims 1 to 8, wherein the reaction temperature for reacting 1,1-dichloro-2,3,3,3-tetrafluoropropene with hydrogen is 200 ° C. or lower.

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