WO2018030408A1

WO2018030408A1 - Method for producing 1-chloro-2, 3, 3, 3-tetrafluoropropene

Info

Publication number: WO2018030408A1
Application number: PCT/JP2017/028779
Authority: WO
Inventors: 真吾野村; 岡本　秀一
Original assignee: 旭硝子株式会社
Priority date: 2016-08-09
Filing date: 2017-08-08
Publication date: 2018-02-15
Also published as: CN109563010B; JPWO2018030408A1; CN109563010A; JP6881457B2

Abstract

Provided is an efficient method for producing 1-chloro-2, 3, 3, 3-tetrafluoropropene by reducing 1,1-dichloro-2, 3, 3, 3-tetrafluoropropene, the method generating fewer by-products such as 1, 1, 1-trifluoropropane and 3, 3, 3-trifluoropropene that are products of over-reduction. The method for producing 1-chloro-2, 3, 3, 3-tetrafluoropropene is characterized by obtaining 1-chloro-2, 3, 3, 3-tetrafluoropropene by reacting, in a vapor phase, 1,1-dichloro-2, 3, 3, 3-tetrafluoropropene with hydrogen in the presence of a palladium catalyst-supporting carrier that is obtained by having a carrier support a palladium catalyst that comprises chlorine and a metal containing palladium so that the ratio of the number of moles of chlorine atoms to the number of moles of palladium atoms, namely Cl/Pd, is 2.0 or more.

Description

Process for producing 1-chloro-2,3,3,3-tetrafluoropropene

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) It is a compound with a low global warming potential (GWP) and less burden on the global environment, which is newly useful for cleaning agents, refrigerants, foaming agents, solvents, aerosols and the like in place of chlorofluorocarbons such as).

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). Is reduced by reacting with hydrogen in the presence of a palladium catalyst to obtain 2,3,3,3-tetrafluoropropene (CF ₃ CF═CH ₂ , HFO-1234yf), thereby obtaining 1224yd as an intermediate. It is described that In Patent Document 1, 1224yd obtained as an intermediate in the above reaction is used as a raw material compound for HFO-1234yf together with 1214ya.

In the above Patent Document 1, there is a description of conditions and means for obtaining HFO-1234yf as a target substance in a high yield in a method of reducing 1214ya by reacting with hydrogen, but 1224yd, which is positioned as a byproduct, is efficiently obtained. There is no description of how to obtain. That is, in the method of Patent Document 1, 1224yd is also produced to some extent, but for 1224yd, HFO-1234yf, which is a hyperreductant, and 1,1,1,2-tetrafluoropropane (CF ₃ CHFCH, which is a reductant thereof, are also used. 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 etc. are by-produced.

International Publication No. 2011/162341

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

In this specification, for halogenated hydrocarbons, the abbreviations of the compounds are shown in parentheses after the compound names. In the present specification, the abbreviations are used instead of the compound names as necessary.

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

The present invention provides a method for producing 1224yd having the following configuration.
[1] A palladium catalyst carrying a palladium catalyst having a palladium-containing metal and chlorine and having a ratio of the number of moles of chlorine to the number of moles of palladium (Cl / Pd) of 2.0 or more. Reacting 1,1-dichloro-2,3,3,3-tetrafluoropropene with hydrogen in the gas phase in the presence of a carrier to obtain 1-chloro-2,3,3,3-tetrafluoropropene. A method for producing 1-chloro-2,3,3,3-tetrafluoropropene, which is characterized.
[2] The production method according to [1], wherein the ratio of the number of moles of chlorine atoms to the number of moles of palladium atoms (Cl / Pd) is 2.0 to 5.0.
[3] The production method according to [1] or [2], wherein a ratio of a 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 a 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 palladium alone.
[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. [7] 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 obtaining 1224yd by reducing 1214ya for which a stable production method has been established, and is a method that is industrially easy to implement and can be carried out stably. In addition, according to the method for producing 1224yd of the present invention, it is possible to efficiently produce 1224yd with excellent selectivity while reducing by-products such as HFC-263fb and HFO-1243zf which are hyperreductants.

It is the schematic diagram which showed the reaction apparatus used for the Example.

The production method of 1224yd according to the present invention uses a palladium catalyst having a palladium-containing metal and chlorine, and having a ratio of the number of moles of chlorine atoms to the number of moles of palladium atoms (Cl / Pd) of 2.0 or more. In the presence of a supported palladium catalyst support, 1214ya is reacted with hydrogen (hereinafter also referred to as H ₂ ) in the gas phase.
The reaction of 1214ya and hydrogen according to the production method of 1224yd of the present invention is represented by the following formula (1).

1224yd obtained by the production method of the present invention may be a mixture of a Z-form and an E-form, may be a Z-form alone, or may be an E-form alone. 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. There is little influence and GWP is small. Therefore, it is highly useful for cleaning agents, refrigerants, foaming agents, solvents, and aerosol applications.

<1214ya>
The manufacturing method of 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. For example, as shown in formula (2), HCFC-225ca can be produced by a dehydrofluorination reaction by contacting it with an alkaline aqueous solution in the presence of a phase transfer catalyst. .

The HCFC-225ca used in the reaction of the formula (2) can be used in the form of a dichloropentafluoropropane (HCFC-225) isomer mixture containing HCFC-225ca and its isomer. When the HCFC-225 isomer mixture is used, only the HCFC-225ca in the HCFC-225 isomer mixture is selectively dehydrofluorinated 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 preferred.

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-225cb 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 included 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 Asahiklin AK225 (manufactured by Asahi Glass Co., Ltd., trade name: 48 mol% of HCFC-225ca and 52 mol% of HCFC-225cb).

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

In the present invention, by performing the reaction of the above formula (1) in the presence of the palladium catalyst-supporting carrier (X), the by-product such as HFC-263fb and HFO-1243zf, which are overreduced substances, is reduced and the selectivity is increased. This makes it possible to produce excellent and efficient 1224yd.

In the present invention, the palladium catalyst in the palladium catalyst-supported 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 metal (M). The metal (M) may be composed only of palladium, or may include a metal other than palladium (hereinafter also referred to as “other metal”). It is preferable from the viewpoint of reducing by-products that the metal (M) is mainly composed of palladium, specifically, the ratio of the other metal to 100 parts by mass of palladium in the metal (M) is 50 parts by mass or less. The proportion of the other metal with respect to 100 parts by mass of palladium is preferably 30 parts by mass or less, and more preferably 10 parts by mass or less from the viewpoint of reducing by-products. The metal (M) does not contain any metal other than palladium, that is, it is particularly preferable that it is a simple substance of palladium because a high catalytic activity is 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: rhenium, zinc, cadmium, tin, lead, antimony, bismuth 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 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 other metals in addition to palladium is used, the catalyst durability is higher than when a metal (M) made of palladium alone is used.

The palladium catalyst in the palladium catalyst support (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. 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. The calculation is carried out by treating a palladium-supported carrier (Y ₀ ) on which 0.5% by mass of palladium is supported on the surface of silicon dioxide with a predetermined amount of hydrogen chloride and supporting a palladium catalyst having palladium and chlorine. The carrier (Y) is used as a standard.

[Calculation method of Cl / Pd]
(I) A palladium-supported carrier (Y ₀ ) having 0.5 mass% palladium supported on the surface of silicon dioxide and silicon dioxide are prepared.
(Ii) 70 g of palladium-supported carrier (Y ₀ ) is weighed and filled into a U-tube made of SUS314 having an inner diameter of 21.4 cm, and hydrogen chloride gas is allowed to flow for 120 minutes at 45 ° C. and a gas flow rate of 300 mL / min. 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. The palladium catalyst-supported carrier (Y) on which the palladium catalyst containing palladium and chlorine obtained by the above-described treatment was recovered from the inside of the U-shaped tube, and the content of chlorine atoms on the surface (atom%; in the formula (3) And the palladium atom content (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 carrying out the same treatment as in (ii) above, the chlorine atom content (atom%; “b” in formula (3)) on the surface is X. It is determined by linear photoelectron spectroscopy (XPS) wide spectrum measurement.

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

Cl / Pd (denoted by [Cl / Pd] _(x) in the formula (4) ₎ of the palladium catalyst-supported support (X) is added to the palladium catalyst-supported support (X) in the above [Cl / Pd] _(y ). The following equation (4) is obtained by multiplying the palladium loading correction coefficient given by the type of the carrier used in the above and the correction coefficient based on the amount of hydrogen chloride treated when the palladium catalyst carrying carrier (X) is produced.
[Cl / Pd] _(x) = [Cl / Pd] _(y) × c × d Equation (4)

c: hydrogen chloride throughput correction coefficient c is the palladium catalyst support (X) based on the hydrogen chloride throughput per unit mass (300 mL / min, 120 minutes) when producing the palladium catalyst support (Y) This is a value obtained by dividing the amount of hydrogen chloride treated per unit mass at the time of manufacturing by the above criteria.

d: Palladium carrying amount correction coefficient d is a coefficient given by the difference in the carrier between the palladium catalyst carrying carrier (Y) and the palladium catalyst carrying carrier (X). For example, when the support of the palladium catalyst-supported carrier (X) is coconut shell activated carbon, the coconut shell activated carbon can support 1.4 times the mass of palladium with respect to silicon dioxide which is the support of the palladium catalyst-supported 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 d is a 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 a palladium catalyst-supported carrier (X) supported on a carrier. Examples of the carrier include activated carbon and metal oxides such as alumina, zirconia, silica, and titania. Among these, activated carbon is preferable from the viewpoint of catalytic activity, durability, and reaction selectivity.

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

The amount of 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 carrier, as the amount of 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. If the supported amount of the palladium catalyst is not more than the upper limit, it is easy to suppress an excessive temperature rise of the catalyst layer (described later) due to reaction heat, and it is easy to reduce the production of by-products.

Specifically, the palladium catalyst-supported carrier (X) is a metal (M) -supported carrier on which the metal (M) is supported, and Cl / Pd in the obtained palladium catalyst-supported carrier (X) falls within the above predetermined range. Thus, it can prepare by processing with hydrogen chloride gas. As a method of supporting the metal (M) on the support, a method of supporting a metal catalyst on the support can be used without any particular limitation. For example, when palladium alone is a metal (M) and the carrier is activated carbon, the activated carbon is impregnated with an aqueous solution of a palladium salt such as palladium chloride (II), palladium nitrate (II), tetraamine palladium (II) chloride and dried. Thus, after depositing a palladium salt on the surface of the activated carbon, palladium ions in the palladium salt are reduced with hydrogen gas to obtain a 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 metal (M) -supported carrier is filled in a reactor similar to that used in the production of 1224yd, and hydrogen chloride gas is supplied to the reactor while adjusting the temperature of the reactor with an oil bath or the like. The palladium catalyst-supported carrier (X) can be prepared with 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., but the Cl / Pd in the palladium catalyst is reduced by approximately 1 to 20 hours. A palladium catalyst-supported carrier (X) adjusted to the above range is obtained.

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

<Manufacture 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-supported support (X), specifically, a catalyst layer filled with the palladium catalyst-supported support (X) is formed. And a method of introducing 1214ya and hydrogen into the catalyst layer in a gaseous state.

In the present invention, the catalyst layer is usually formed by filling the reactor with a palladium catalyst-supported carrier (X). The packing density of the palladium catalyst-loaded support (X) in the catalyst layer is preferably 0.3 ~ 1g / cm ^3, more preferably 0.4 ~ 0.8g / cm ^3. If the packing density of the palladium catalyst-carrying support (X) is equal to or higher than the lower limit, the amount of palladium catalyst-carrying support (X) per unit volume is large, and the amount of gas to be reacted can be increased, thereby improving productivity. To do. If the packing density of the palladium catalyst-carrying support (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 production of by-products. There may be one packed portion of the palladium catalyst-supporting support (X), that is, the catalyst layer in the reactor, or two or more.

In order to perform 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, the product gas containing 1224yd is discharged from the side of the catalyst layer opposite to the side where 1214ya and hydrogen are introduced. Hereinafter, the production method of the present invention will be described by taking the case of using a catalyst layer as an example. The side of the catalyst layer where 1214ya and hydrogen are introduced is referred to as a “gas introduction part”, and the side where the product gas is discharged is referred to as a “gas discharge part”.

The ratio of 1214ya and hydrogen introduced into the catalyst layer is the ratio between the number of moles of 1214ya and the number of moles of hydrogen (H ₂ / 1214ya), and the value is preferably 1.4 or less. The smaller the molar ratio of 1214ya and hydrogen (H ₂ / 1214ya), the easier it is to reduce by-products such as HFC-263fb and HFO-1243zf, and it is more preferably 1.2 or less and even more preferably 1.0 or less. Further, 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 1224yd. The molar ratio (H ₂ / 1214ya) is preferably 0.2 or more and 1.4 or less, from the viewpoint of reducing by-products such as HFC-263fb and HFO-1243zf, and the yield of 1224yd, and is preferably 0.4 or more. 1.2 or less is more preferable, and 0.5 or more and 1.0 or less is most preferable.

When hydrogen is dividedly introduced as in the method (A) described later, similarly, the ratio of 1214ya introduced into the catalyst layer and 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. Further, 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 at which 1214ya reacts with hydrogen is a gas phase reaction, and therefore a mixed gas of 1214ya and hydrogen used for the reaction, but when an inert gas is used, The temperature exceeds the dew point of the active gas mixture. In the production method of the present invention, the reaction temperature is preferably 200 ° C. or less, more preferably 190 ° C. or less, and particularly preferably 150 to 190 ° C. from the viewpoint of suppressing the formation of by-products.

The reaction temperature in the production method of the present invention is specifically indicated by the temperature in the reaction zone of the catalyst layer described below. In the production method of the present invention, by controlling the temperature of the reaction zone 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 with the progress of catalyst deterioration, 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 temperature is maintained by heating the catalyst layer from the outside with a heating medium or the like, the temperature drop of the catalyst layer can be prevented by gradually increasing the temperature of the heating 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 refers to the temperature of the catalyst layer that is maintained by external heating or the like. Usually, 1214ya and hydrogen react in a partial region of the catalyst layer, and the reaction zone (region where 1214ya and hydrogen react) becomes higher in temperature than the other catalyst layer regions due to the generation of reaction heat. As the catalytic activity of the reaction zone decreases with time, the reaction zone usually gradually moves from the vicinity of the gas introduction portion to the downstream side in the gas flow direction. Further, a product gas having a high temperature generated in the reaction zone flows on the downstream side of the reaction zone, and usually becomes higher than the temperature of the catalyst layer, and gradually decreases as the distance from the reaction zone increases. In the present invention, the temperature of the catalyst layer refers to the temperature on the upstream side of the reaction zone, that is, the temperature of the catalyst layer that is heated from the outside with a heating medium or the like to maintain the temperature.

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 not more than the upper limit value of the reaction temperature. As described above, the temperature in the reaction zone where 1214ya reacts with hydrogen and the downstream region thereof become higher than the temperature of the catalyst layer in the other region 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 that is higher than the other regions due to the generation of the reaction heat. In addition, as a measuring method of the maximum temperature of the catalyst layer in reaction, the following measuring method using an insertion type thermometer is mentioned, for example.

In the reaction of 1214ya and hydrogen in the catalyst layer, first, the catalyst in the vicinity of the gas introduction part into which these are introduced in a gaseous state contributes to the reaction, and when the catalyst in the vicinity of the gas introduction part deteriorates, the downstream catalyst reacts. As it contributes, the reaction zone in the catalyst layer gradually moves toward the gas discharge side. That is, since the portion showing the maximum temperature of the catalyst layer moves with the movement of the reaction zone of 1214ya and hydrogen, the measurement part of the insertion type thermometer is positioned in the gas introduction part of the catalyst layer in advance. The maximum temperature of the catalyst layer can be measured by moving the measuring unit as the reaction proceeds.

As a method of maintaining the maximum temperature of the catalyst layer during the reaction below the upper limit of the above reaction temperature, hydrogen is divided into the catalyst layer from the viewpoint of easily maintaining high productivity while controlling the maximum temperature of the catalyst layer low. Thus, the method of introduction (method (A)) is preferred. If hydrogen is divided and introduced into a plurality of portions of the catalyst layer, the reaction zone of the catalyst layer can be dispersed without changing the amount of introduction of 1214ya, so that the generation of reaction heat is not concentrated in one place. Therefore, local excessive heat generation of the catalyst layer can be easily suppressed without reducing productivity.

Hydrogen split introduction means introduction of 1214ya and hydrogen into the gas introduction part of the catalyst layer and introduction of hydrogen from at least one place between the gas introduction part and the gas discharge part of the catalyst layer. That is, hydrogen is introduced from at least one location of the catalyst layer other than the gas introduction portion, that is, from a total of 2 or more locations.

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 the 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 (usually a product gas after a part of 1214ya has reacted with hydrogen) flowing through the catalyst layer at the introduction position is hydrogen. The unreacted 1214ya reacts with hydrogen in the catalyst layer downstream 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). Exhaust the gas.

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

The introduction of hydrogen in the method (A) may be divided and introduced into two places or may be introduced into three or more places. From the viewpoint of simplifying the process, it is preferable to introduce hydrogen from two places. It is preferable that the amount of hydrogen introduced separately in two or more places in the catalyst layer is equal to the amount of each hydrogen introduced separately in that the maximum temperature of the catalyst layer can be easily maintained low.

When there are two or more catalyst layers in the reactor, for example, hydrogen can be dividedly introduced by introducing a part of hydrogen into the catalyst layer on the most upstream side (first stage) together with 1214ya and the remaining part downstream from the first stage. The method of introduce | transducing into the catalyst layer after the 2nd step | paragraph of the side is mentioned.

Further, as a method for controlling the maximum temperature of the catalyst layer other than the method (A), there is a method (method (B)) in which an inert gas is allowed to flow through the catalyst layer together with 1214ya and hydrogen. By causing the inert gas to flow and adjusting the concentration of 1214ya and hydrogen flowing in the catalyst layer, an excessive temperature rise of the catalyst layer due to reaction heat can be suppressed. Further, a diluent 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, rare gases (such as helium and argon), carbon dioxide, and chlorofluorocarbons inert to the hydrogenation reaction.

The amount of the inert gas introduced into the catalyst layer is less than 1 mol of 1214ya because it is easy to maintain the maximum temperature of the catalyst layer low, to easily reduce the formation of by-products, and to suppress deterioration of the catalyst. 0.5 mol or more is preferable, and 1.0 mol or more is more preferable. Further, the introduction amount of the inert gas is preferably 10.0 mol or less and more preferably 4.0 mol or less with respect to 1 mol of 1214ya from the viewpoint of the recovery rate of the inert gas. From the point that it is easy to reduce the production of by-products, the point that it is easy to suppress deterioration of the catalyst, and the point of the recovery rate of the inert gas, 0.5 mol or more and 10.0 mol or less are preferable with respect to 1 mol of 1214ya 1.0 mol or more and 4.0 mol or less is more preferable.

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 for the reaction as the lower limit. A method (method (C)) is mentioned. When an inert gas is used, the temperature is set to a lower temperature with the dew point of the mixed gas of 1214ya, hydrogen and inert gas as the lower limit. By keeping the temperature of the catalyst layer low, it is possible to remove the heat of reaction more quickly and suppress an excessive increase in temperature of the catalyst layer.

In the method (C), the lower the temperature of the catalyst layer, the more advantageous it is to suppress the production of by-products that are difficult to separate from the target product 1224yd, and in the reaction in a state where the raw material is liquefied, The temperature of the catalyst layer is preferably higher than the dew point of the above mixed gas from the viewpoint that the yield of 1224yd decreases due to an increase in the production of by-products in which 1224yd is excessively reduced. More preferably, it is higher than the dew point and lower than 50 ° C., more preferably higher than the dew point and not higher 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), respectively, or use two or three of them together.

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 respect to the palladium catalyst-supported support (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, Most preferred is ˜10 cm / sec. When the linear velocity u is 0.1 cm / second or more, productivity is improved and 1214ya tends to flow uniformly through the catalyst layer. If the linear velocity u is 100 cm / sec or less, the reaction rate between 1214ya and hydrogen is improved, and if the linear velocity u is 30 cm / sec or less, temperature control near the reaction point by heat generation becomes easy.

The linear velocity u is calculated by the following equation (5) from the gas amount of 1214ya introduced into the reactor and the volume of the catalyst layer.
u = (W / 100) × V / S Formula (5)
W: 1214ya concentration (mol%) in the total gas flowing through the catalyst layer
V: Flow rate of all gases 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 to be introduced into the catalyst layer include, in addition to 1214ya, hydrogen, an inert gas as an optional component, and a dilution gas, other components within a range that does not impair the effects of the present invention. It may be included. Examples of the other components include a component that is brought together with 1214ya as an impurity when 1214ya is prepared.

Examples of the reactor used in the production method of the present invention include known reactors that can be filled with a catalyst-supporting carrier to form a catalyst layer. Examples of the material for the reactor include glass, iron, nickel, and alloys containing these as main components.

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

The HCl contained in the product gas can be removed by, for example, 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. Note that the amount of HCl contained in the product gas is small and does not particularly affect Cl / Pd of the palladium catalyst-supported carrier. As a method for recovering 1224yd from the product gas, for example, a known method such as fractional distillation can be employed. The obtained 1224yd is usually a mixture of E-form and Z-form of 1224yd. When separation of E-form and Z-form of 1224yd from the mixture is necessary, 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 of the number of moles of chlorine atoms to the number of moles of palladium atoms (Cl / Pd) is 2.0 or more. By reacting 1214ya with hydrogen in the gas phase in the presence of a palladium catalyst-carrying carrier on which the carrier is supported, a by-product such as HFO-1234yf, HFC-254eb, HFC-263fb, HFO-1243zf, etc., which are overreduced substances Is reduced. According to the production method of the present invention, the effect of suppressing 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 1224yd in the product gas increases, so that it is possible to efficiently produce 1224yd with excellent selectivity. Moreover, about 1214ya used for reaction, since it is a compound with which the stable manufacturing method was established from the easily available raw material, the manufacturing method of this invention is industrially easy to implement, and the method which can be implemented stably. I can say that.

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

First, the palladium catalyst-supported carrier used in each example was prepared as follows. The palladium catalyst support (X1) and (X2) are the palladium catalyst support according to the present invention, and the palladium catalyst support (Cf1) is the palladium catalyst support for the comparative example. In addition, for preparing each palladium catalyst-supported carrier, palladium-supported activated carbon in which 0.5% by mass of palladium was supported on 100% by mass of coconut shell activated carbon having a particle size of 4 to 8 mesh (manufactured by N.E. Hereinafter referred to as “palladium-supported activated carbon (A)”).

Further, in order to calculate Cl / Pd of the palladium catalyst-supported carrier, the above measurements (ii) and (iii) were performed, and [Cl / Pd] _(y) was obtained from the equation (3). Cl / Pd of each palladium catalyst-supported carrier was calculated according to the equation (4) from [Cl / Pd] _(y) and the conditions of the carrier and hydrogen chloride treatment in each palladium catalyst-supported carrier.

When Cl / Pd in the palladium-supported activated carbon (A) is calculated by the above calculation method, Cl / Pd is 0.0 because hydrogen chloride treatment is not performed. 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 a reaction tube of the same apparatus as the following reaction apparatus. While maintaining the temperature of the oil bath in which the reaction tube was immersed at 45 ° C., the palladium catalyst-supported support (X1) was allowed to flow through the palladium-supported activated carbon (A) at a flow rate of 300 mL / second for 2 hours. Obtained. It was 2.2 when Cl / Pd of the palladium catalyst in the obtained palladium catalyst support (X1) was calculated by the above calculation method.

[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-supported carrier (X2) was calculated by the above calculation method and found to be 4.6.

[Example 1]
For the production of 1224yd, the reaction apparatus 100 schematically shown in FIG. 1 was used. As shown in FIG. 1, the reaction apparatus 100 includes a single 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 in which the palladium catalyst-supported support (X1) (Cl / Pd = 2.2) prepared above is packed at a packing density of 0.73 g / cm ³ on the outlet 11 side. It has a layer 10. Perfluoroether FOMBLIN ^(R) YLVAC (Solvay) was used as the heating medium for the oil bath.

The reaction apparatus 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 through pipes 4, 5, and 6, respectively. ing. The gas discharged from the outlet 11 of the reaction tube 8 is transferred to the alkali cleaning tank 14 through the pipe 13 and is recovered in the product gas storage container 16 through the pipe 15 after the alkali cleaning. 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 alkali cleaning of the outlet gas is referred to as “product 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 all immersed, and the catalyst layer 10 was heated to 45 ° C. Next, 1214ya gas, hydrogen gas and nitrogen gas were passed through the reaction tube 8, and the discharged outlet gas was washed with alkali to obtain a product gas.

The contact time of 1214ya gas with respect to the palladium catalyst support (X1) packed in the catalyst layer 10 is 12 seconds, and the ratio between the number of moles of 1214ya gas and the number of moles of the total amount of hydrogen gas introduced into the catalyst layer ( H ₂ / 1214ya) was set to 1.0. The ratio (N ₂ / 1214ya) between the number of moles of 1214ya gas and the number of moles of the total amount of nitrogen gas introduced into the catalyst layer was 2.0. The linear velocity u of 1214ya was 0.8 cm / second.

Further, the maximum temperature (reaction temperature) of the catalyst layer 10 during the reaction was measured by a plug-in thermometer 12 inserted in the catalyst layer, and was 171 ° C. The alkali 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. It was 183 degreeC when the maximum temperature of the catalyst layer 10 during reaction was measured with the insertion type thermometer 12 inserted in the catalyst layer.

[Example 3]
A product gas was obtained in the same manner as in Example 1 except that the palladium catalyst-supported support (X1) (Cl / Pd = 2.2) was changed to the palladium catalyst-supported support (X2) (Cl / Pd = 4.6). . It was 153 degreeC when the maximum temperature of the catalyst layer 10 during reaction was measured with the insertion type thermometer 12 inserted in the catalyst layer.

[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 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 support (X1) (Cl / Pd = 2.2) was changed to the palladium catalyst-supported support (Cf1) (Cl / Pd = 0.0). . It was 153 degreeC when the maximum temperature of the catalyst layer 10 during reaction was measured with the insertion type thermometer 12 inserted in the catalyst layer.

[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 thermometer 12 inserted into the catalyst layer, and found to be 171 ° C.

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

X = [a / (a + b + c)] × 100 Formula (6)
Y = [b / (a + b + c)] × 100 Formula (7)
(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 a hyperreductant (HFO-1234yf, HFC- 254eb, HFC-263fb, HFO-1243zf, etc.)

Moreover, the yield of 1224yd (Z body and E body) was computed by the following Formula (8).
Yield of 1224yd (Z-form and E-form) = [A × (X + Y)] / 100 Formula (8)
(However, in Formula (8), "A" shows the reaction rate of 1214ya.)

The analysis results are shown in Table 1 together with the reaction conditions. Table 2 shows the area ratio in the GC analysis of the product gas as a molar ratio (unit: mol%). In addition, the kind of palladium catalyst carrying | support carrier in Table 1 shows only a code | symbol.

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

According to the production method of the present invention, high purity 1224yd can be produced by suppressing the production of reductants such as HFC-263fb and HFO-1243zf in the method of obtaining 1224yd by reducing 1214ya. And 1224yd obtained by the method of the present invention has a small global warming potential (GWP), and is useful as a substitute for chlorofluorocarbons for cleaning agents, refrigerants, foaming agents, solvents, aerosols, and the like.

DESCRIPTION OF SYMBOLS 100 ... Reaction apparatus, 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 Pipe outlet, 12 ... thermometer, 14 ... alkaline washing tank, 16 ... generated gas storage container.

Claims

Existence of a palladium catalyst-supported carrier comprising a palladium catalyst having a palladium-containing metal and chlorine, and a palladium catalyst having a ratio of the number of moles of chlorine to the number of moles of palladium (Cl / Pd) of 2.0 or more. 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 of the number of moles of chlorine atoms to the number of moles of palladium atoms (Cl / Pd) is 2.0 to 5.0.
The production method according to claim 1 or 2, wherein a ratio of a 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 a mass ratio of the metal containing palladium to the carrier is 0.1 to 10 mass%.
The method according to any one of claims 1 to 4, wherein the metal containing palladium is palladium alone.
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.
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 claim 1.
The production method according to any one of claims 1 to 8, wherein a reaction temperature at which the 1,1-dichloro-2,3,3,3-tetrafluoropropene is reacted with hydrogen is 200 ° C or lower.