FR3016627B1 - PROCESS FOR PRODUCING E-1-CHLORO-3,3,3-TRIFLUOROPROPENE FROM 1,1,3,3-TETRACHLOROPROPENE - Google Patents

Abstract

The present invention relates to a process for the manufacture of E-1-chloro-3,3,3-trifluoropropene comprising at least one step in which the 1,1,3,3-reacts with anhydrous hydrofluoric acid in the liquid phase, in the absence of catalyst. It also relates to the steps of separation and purification of the flow resulting from the reaction.

Description

PROCESS FOR PRODUCING E-1-CHLORO-3,3,3-TRIFLUOROPROPENE FROM 1,1,3,3-TETRACHLOROPROPENE

FIELD OF THE INVENTION

The present invention relates to a process for the continuous manufacture of E-1-chloro-3,3,3-trifluoropropene (E-1233zd) comprising at least one step of liquid-phase fluorination of 1,1,3,3-tetrachloropropene (1230za ). It also relates to an installation adapted to the implementation of this process on an industrial scale.

TECHNICAL BACKGROUND

E-1-chloro-3,3,3-trifluoropropene (E-1233zd) can be made by fluorinating 1,1,1,3,3-pentachloropropane (240fa). For example, documents US Pat. No. 8,436,217 and US Pat. No. 8,426,656 describe the fluorination of 240fa in E-1233zd in the liquid phase, in the presence of suitable catalysts such as TiCL or a combination of TiCL and SbCls.

The document FR2768727 also teaches that the fluorination of 240fa or 1230za is feasible in the presence of a catalyst such as TiCL.

Documents US2010 / 0191025 and US 6,166,274 also disclose the use of a catalyst for the liquid phase fluorination of 1230za to obtain E-1233zd: an ionic liquid based catalyst for the first material and a triflic acid or trifluoroacetic for the second document.

US 2012/0059199 discloses the liquid phase fluorination of 240fa in the absence of catalyst. This document teaches that a disadvantage of the uncatalyzed liquid phase process is the low conversion rate of the reaction. Several reactors in series are therefore necessary to increase the overall conversion rate, each of the reactors contributing to the advancement of the conversion rate.

US 2013/0211154 discloses the use of a high reaction pressure associated with a stirred fluorination reactor to increase the conversion rate in a non-catalyzed liquid phase process of 240fa. However, there is no accuracy of the conversion rate.

US 6,987,206 discloses the possibility of obtaining E-1233zd from 1230za as an intermediate without indication of operating conditions.

The uncatalyzed liquid phase reaction of 1230za fluorination is exemplified in US 5,616,819. The pressure used is 200 psi (14 bar) and gives rise to the formation of oligomers despite the short duration of the batch test.

US 5,877,359 discloses the non-catalyzed liquid phase fluorination of 1230za. The examples show that a very high molar ratio of 166 was used to obtain complete conversion on a short batch test. When the molar ratio is decreased to 12.6, a pressure of 600psig (42 bar) is applied. On the other hand, the operating conditions of an extrapolatable continuous process are therefore not defined: molar ratio HF / 1230za, reflux temperature, nature of the by-products to be distilled. The productivity or the stability over time of a process based on this reaction are not described either.

There is still a need to develop a novel process for the continuous and extrapolatable production of E-1233zd of stringent operating conditions such as excessive pressure, high molar ratio or agitation in the fluorination reactor.

SUMMARY OF THE INVENTION

The present invention overcomes the disadvantages of the state of the art. It more particularly provides a novel process for producing E-1-chloro-3,3,3-trifluoropropene.

This is accomplished by the simplified implementation of the fluorination of 1230za to E-1233zd by liquid phase hydrogen fluoride in the absence of catalyst.

The present invention also relates to an industrial process for the manufacture of E-1-chloro-3,3,3-trifluoropropene including the various operations of separation and recycling.

The present invention further relates to an installation for implementing the various embodiments of the method.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION The invention is now described in more detail and in a nonlimiting manner in the description which follows.

According to the present invention, the process comprises at least one step in which 1,1,3,3-tetrachloropropene reacts with anhydrous hydrofluoric acid in the liquid phase in the absence of catalyst with a molar ratio HF / 1 , 1,3,3-tetrachloropropene between 3 and 20, at a temperature between 50 and 150 ° C and an absolute pressure between 1 and 20 bar.

The present invention also relates to a process for the manufacture of E-1-chloro-3,3,3-trifluoropropene comprising (i) at least one step in which 1,1,3,3-tetrachloropropene reacts with anhydrous hydrofluoric acid in the liquid phase in a reactor equipped with a purge and an effluent outlet; (ii) at least one step of treating the effluent from the reactor to give a stream A comprising E-1-chloro-3,3,3-trifluoropropene, HCl, HF and Z-1-chloro-3, 3,3-trifluoropropene and a stream B comprising predominantly HF (for example at least 50% by weight, preferably at least 70% by weight of HF); (iii) at least one step of recovering hydrochloric acid from stream A to give a stream C of HCl and a stream D comprising E-1-chloro-3,3,3-trifluoropropene, HCl, HF and the Z-1-chloro-3,3,3-trifluoropropene; (iv) at least one D-stream purification step from step (iii) to give E-1233zd, preferably with a purity greater than or equal to 98%, preferably greater than or equal to 99%, and very advantageously greater than or equal to 99.9% by weight.

The present invention further relates to a process for the manufacture of E-1-chloro-3,3,3-trifluoropropene comprising (i) at least one step in which 1,1,3,3-tetrachloropropene reacts with anhydrous hydrofluoric acid in the liquid phase in a reactor in the absence of a catalyst with a molar ratio of HF / 1,1,3,3-tetrachloropropene of between 3 and 20 at a temperature of between 50 and 150.degree. an absolute pressure of between 1 and 20 bar, (ii) at least one step of treating the effluent from the reactor to give a stream A comprising E-1-chloro-3,3,3-trifluoropropene, HCl, HF and Z-1-chloro-3,3,3-trifluoropropene and a stream B comprising predominantly HF (for example at least 50% by weight, preferably at least 70% by weight of HF); (iii) at least one step of recovering hydrochloric acid from stream A to give a stream C of HCl and a stream D comprising E-1-chloro-3,3,3-trifluoropropene, HCl, HF and the Z-1-chloro-3,3,3-trifluoropropene; (iv) at least one D-stream purification step from step (iii) to give E-1233zd, preferably with a purity greater than or equal to 98%, preferably greater than or equal to 99%, and very advantageously greater than or equal to 99.9% by weight.

Preferably, before the purification step, the flow D resulting from step (iii) is subjected to at least one separation step to give a flow mainly comprising HF (for example at least 90% by weight, of preferably at least 98% by weight and advantageously at least 99% by weight of HF) which can be recycled to the reactor and a stream comprising E-1-chloro-3,3,3-trifluoropropene, HCl, HF and Z- 1-chloro-3,3,3-trifluoropropene. The separation step is preferably a settling, carried out at a temperature advantageously between -50 and 50 ° C. The treatment step (ii) is preferably a reflux column, advantageously carried out at a temperature between 30 and 120 ° C to give the condensable flow B which is recycled to the reactor.

Recovery of HCl in step (iii) is preferably achieved using a distillation column with a bottom reboiler and overhead reflux system. The temperature in the foot is advantageously between 20 and 110 ° C. The temperature at the head is advantageously between -50 and 0 ° C. The purification step (iv) preferably comprises at least one distillation step and advantageously at least two distillation steps.

Stream A may further comprise organic compounds such as fluorination reaction intermediates or by-products. Mention may in particular be made of dichlorodifluoropropene, trichloromonofluoropropene, fluorotetrachloropropane, pentafluoropropane, difluorotrichloropropane, dichlorotrifluoropropane and 1,3,3,3-tetrafluoropropene.

The process according to the present invention may further comprise a purge step which, after treatment, can be recycled to the reactor.

The molar ratio HF / 1,1,3,3-tetrachloropropene is preferably between 5 and 15, and advantageously between 9 and 12.

The reaction temperature is preferably between 80 and 120, and advantageously between 90 and 110 ° C.

The fluorination reaction is preferably carried out at a pressure of between 5 and 15 bar, and advantageously between 7 and 12 bar. The fluorination reaction is preferably carried out in an unstirred reactor.

The method according to the present invention can be implemented continuously, batchwise or batchwise. It is preferred to operate continuously.

The method according to the present invention offers the advantage of obtaining a very interesting yield and selectivity while using mild conditions. In addition, these results can be obtained using a single reactor.

EMBODIMENT OF THE INVENTION

Figure 1 schematically shows an embodiment of the method according to the invention and an installation for its implementation.

Unless otherwise stated, all percentages given below are percentages by weight. The invention provides for the fluorination of 1230za to E-1233zd with liquid phase hydrogen fluoride in the absence of catalyst.

Referring to Figure 1, the plant according to the invention comprises a catalytic reactor 3 for carrying out the fluorination reaction of 1230za E-1233zd.

The reactor 3 is fed by a supply line of 1,1,3,3-tetrachloropropene 2 and a supply line of hydrogen fluoride 1_. Heating means are preferably provided for preheating the reagents before their arrival in the reactor 3.

The aforementioned supply lines can feed the reactor 3 separately or can be connected together upstream of the reactor to feed it as a mixture of reagents.

The reactor 3 is preferably a metal reactor. The reactor metal may be steel or stainless steel. However, other materials such as a superaustenitic stainless steel or a passivable nickel base alloy can be used. The absence of catalyst for the reaction is an advantage that avoids corrosion phenomena known to those skilled in the art when a fluorination catalyst is used in this type of reactor. All other equipment of the installation and in particular all of the separation columns or distillation columns may be metal.

The reactor 3 may comprise a heating jacket allowing the reaction mixture to be brought to the desired temperature.

A sample line is used to purge a quantity of unwanted high molecular weight products that may have formed during the fluorination reaction. This stream also contains HF and recoverable organic compounds which are separated by a specific treatment before being returned to the reactor. This treatment involves technologies known to those skilled in the art such as decantation or azeotropic distillation, and preferably a combination of both. Stream 16 corresponds to the non-recoverable heavy compounds which must be removed from the process.

A withdrawal pipe of products resulting from the reaction is connected at the outlet of the reactor 3. This pipe carries a flow containing the desired product (E-1233zd), hydrogen chloride, hydrogen fluoride and co-products and sub-products. products of the reaction.

The product withdrawal line from the reaction feeds a preliminary separation unit 4, which is preferably a distillation column provided with an overhead reflux system. This preliminary separation unit ensures a first separation of the HF from the rest of the products resulting from the reaction.

At the head of the preliminary separation unit 4 is connected a first intermediate pipe, which is intended for the collection of the remaining reaction products, and feeds a separation unit 6 intended for the separation of the hydrogen chloride, which is a co-product of the reaction.

Cooling means may be provided on the first intermediate conduit so that the first separation unit operates at the desired temperature. The separation unit 6 is preferably a distillation column provided with a bottom reboiler and an overhead reflux system. It can for example be operated at a pressure slightly lower than that of the reactor 3. At the head of the first separation unit is connected a hydrogen chloride sampling line through which is taken a stream 7 comprising predominantly hydrogen chloride . Traces of E-1233zd or light co-products such as 245fa or E-1234ze may be present in this stream.

The HCl produced is preferably recovered in the form of HCl solution after adiabatic or isothermal absorption in water. HCI can be purified by passing the gas through alumina towers to obtain a desired quality of analysis.

At the bottom of the separation unit 6 is connected a separation system 8 which will allow the separation of the HF and other organic products. This separation system may consist of a first phase separation unit. The HF-rich phase can thus be fed to a separation unit which is preferably an azeotropic distillation column whose bottom fraction is enriched in HF before being recycled to reactor 3 according to line 9 (99.7). % HF, 0.3% E-1233zd). The azeotropic fraction collected at the top is recycled to the separation unit 8.

The phase rich in organic compounds will be collected via line 11 (approximately 90-95% E-1233zd, 3-5% HF, 1-5% Z-1233zd and 0.1-2% by-products and intermediates) and may to be treated by a downstream train of a purification unit 12 comprising at least one additional azeotropic distillation column making it possible to finalize the separation of the HF and a final purification unit making it possible to obtain E-1233zd with a purity greater than or equal to 98% (stream 14 of the figurel).

According to one embodiment, the process comprises two predicted azeotropic distillations: an azeotropic column integrated in the separation system 8 after the settling tank and an azeotropic column in the purification unit 12. The purification unit 12 preferably comprises a first distillation column to remove light products (245fa, E-1234ze or residual traces of HCI) which are removed from the process by the pipe 13.

The gas stream resulting from this first distillation is then treated with an azeotropic column to finalize the separation of the HF. An azeotropic composition is thus collected in the pipe 17 and recycled to the separation unit 8. The composition of this stream is close to that of the stream of the pipe 10, that is to say a mixture of azeotropic HF and E-1233zd.

The resulting gas stream is finally treated with at least one purification column, preferably two columns, to remove a fraction containing predominantly the cis-1233zd isomer and intermediate compounds (for example the 1231, 1232, 241, 242, 243 isomers). ...) which are recycled to the reactor via line 15 and another fraction containing non-recoverable compounds (heavy, 1223xd, ..) which are removed via line 18.

The final product E-1233zd is then collected via line 14 with a purity greater than or equal to 98%, advantageously greater than or equal to 99%, and very advantageously greater than or equal to 99.9% by weight.

EXAMPLES

The following examples illustrate the invention without limiting it.

A first step is to prepare the raw material. 1,1,3,3-Tetrachloropropene is obtained by dehydrochlorinating 1,1,1,3,3-pentachloropropane in the presence of anhydrous ferric chloride.

Example 1 Preparation of 1230za by dehydrochlorination of 240fa

1441.6 g of 1,1,1,3,3-pentachloropropane with a purity of 99.6% are introduced into a glass reactor equipped with a jacket and a reflux. The reactor sky is swept by a nitrogen flow rate of 4 l / h to inert the atmosphere. 14.4 g of anhydrous ferric chloride are then introduced before stirring is started at 800 rpm. The reflux is fed with a fluid maintained at 20 ° C. The condenser gas outlet is connected to a water bubbler which traps the HCI released during the dehydrochlorination reaction. The mixture is then heated at 75 to 80 ° C for several hours (about 4 hours) until gas evolution ceases. 1195.6g of resulting solution are drained from the flask. The mixture obtained is filtered to remove the ferric chloride in suspension and then analyzed by gas chromatography.

Table 1- 240fa dehydrochlorination: composition of the mixture

Example 2 Distillation of 1230za

The low purity 1230za is then subjected to standard laboratory distillation involving a column of 10 trays, a refrigerant, a vacuum pump, a flask and receiving flasks. Distillation is carried out

under a vacuum of 25 mbar, the product 1230za then has a boiling point of 53 ° C. A good purity raw material is obtained having the following composition: 99.33% of 1230za, 0.02% 250fa, 0.15% 240fa, 0.009% C2Cl6 and 0.001% 240db.

Example 3: Continuous liquid phase fluorination of 1230za The equipment used consists of an autoclave with a capacity of 1 liter with a double jacket, made of 316L stainless steel. It is provided with means for measuring temperature and pressure. Apertures at the top of the autoclave allow the introduction of the reagents and the removal of the products. A condenser is provided at the top, as well as a valve for pressure regulation. The condenser is temperature controlled by means of an independent thermostat bath. Its function is to return some of the unreacted HF and intermediates to the reactor.

The products of the reaction are continuously extracted during the reaction. The exit gas stream passes through a washing device which collects HF and HCl hydracids and is then cooled in liquid nitrogen. The molar distribution of the products of the exit gas is periodically analyzed by GPC (gas chromatography). At the end of the test, the reaction medium is depressurized and slowly heated in order to evacuate the residual HF. During this period of degassing, the organic compounds possibly entrained are also recovered after passing through the washing device in order to remove HF and HCl from the gas stream. In a last step, the autoclave is opened and emptied.

The raw material prepared in Example 2 is used for a fluorination reaction.

A quantity of 300 g of HF is introduced into the autoclave. The reactor temperature is adjusted to 92-93 ° C in the liquid phase. The regulation of the pressure is carried out at 10 bar abs. The reagents are then introduced with the following flow rates: 20 g / h of 1230za and 20 g / h of HF. The molar ratio of HF on the organic compound is therefore 9. The establishment of a correct mass balance between the inlet and the outlet is regularly checked. The composition of the output stream is followed by GPC analysis, and reported in Table 2:

Table 2 - molar composition of the exit gas (1230za input rate of 20g / h)

The balance of the composition consists of intermediate products (1231, 1232, 241, 242, 243) and / or unidentified products.

The productivity of the reaction system in F1233zd-E is 0.31 mol / h / L.

Example 4 - continuous fluorination in the liquid phase of 1230za

The procedure of Example 3 is repeated, but doubling the feed rates of organic and HF, 40g / h of 1230za and 40g / h of HF. The molar ratio of HF on the organic compound remains 9.

The composition of the output stream is followed by GPC analysis, and reported in Table 3:

Table 3 - molar composition of the exit gas (1230za input rate of 40g / h)

The productivity of the reaction system in F1233zd-E is 0.68 mol / h / L. Following the tests described in Examples 3 and 4, the reactor was drained. The hydracids were trapped in water, the light organics were cold trapped and the remaining organics in the reactor foot recovered. The level of liquid in the reactor decreased during the test and the composition of the reactor was as follows: 11.3 g HF, 5.6 g HCl, 9 g light organics and 127 g organic compounds accumulated in the reactor. reactor. Chromatographic analysis of these two fractions was performed and allowed to reconstitute the overall composition of the liquid mixture in weight percent: 7.4% HF, 3.7% HCl, 3.5% E-1233zd, 0.25% Z-1233zd, 18.2% of 1230za, 2.4% of 1231, 14.8% of 1232, 49.2% of unidentified compounds.

The conversion of the whole test is calculated on the basis of 27.9g of 1230za found in the liquid phase compared to 3059 g introduced in total, ie 99.1%. The selectivity for E-1233zd over the whole of the continuous test (Example 3 and Example 4) is 89.2%, the selectivity for Z-1233zd is 3.8%, 2% for 1232, 0.7%. % in 1234zeE, 0.7% in 245fa and 2.9% in unknown products.

Example 5 - continuous fluorination in the liquid phase of 1230za

The procedure of Example 3 is reproduced. A quantity of 300 g of HF is introduced into the autoclave. The reactor temperature is adjusted to 91-92 ° C in the liquid phase. The regulation of the pressure is carried out at 10 bar abs. The molar ratio of HF to the organic compound is adjusted to 10 and a longer run test was carried out to establish the stability of the continuous process for 200h. 40 g / h of 1230za and 44 g / h of HF are introduced continuously. The establishment of a correct mass balance between the inlet and the outlet is regularly checked.

The composition of the output stream is followed by GPC analysis, and reported in Table 4:

Table 4 - molar composition of the exit gas (molar ratio of 10, test of longer duration)

The balance of the composition consists of intermediate products (1231, 1232, 241, 242, 243) and / or unidentified products. Following the tests described in Example 5, the reactor was drained. The hydracids were trapped in water, the light organics were cold trapped and the remaining organics in the reactor foot recovered. No trace of 1230za could be detected. The conversion is therefore 100%. The selectivity in E-1233zd is 90-92%. The productivity in E-1233zd is 0.68 mol / h / l. 150g of organic substances were collected in the bottom of the reactor. Considering that 8kgs of 1230za were fed during the test, the production of heavy is calculated at only 1,8%.

Claims (13)

A process for producing E-1-chloro-3,3,3-trifluoropropene comprising (i) at least one step in which 1,1,3,3-tetrachloropropene is reacted with anhydrous hydrofluoric acid in liquid phase in a reactor equipped with a purge and an effluent outlet; in the absence of a catalyst, with a molar ratio of HF / 1,1,3,3-tetrachloropropene of between 3 and 20, at a temperature of between 50 and 150 ° C. and an absolute pressure of between 1 and 20 bar (ii). ) at least one step of treating the effluent from the reactor to give a stream A comprising E-1-chloro-3,3,3-trifluoropropene, HCl, HF and Z-1-chloro-3,3, 3-trifluoropropene and a stream B predominantly comprising HF; (iii) at least one step of recovering hydrochloric acid from stream A to give a stream C of HCl and a stream D comprising E-1-chloro-3,3,3-trifluoropropene, HCl, HF and the Z-1-chloro-3,3,3-trifluoropropene; (iv) at least one step of purifying the D-stream from step (iii) to give E-1233zd, preferably with a purity greater than or equal to 98%, preferably greater than or equal to 99%, and very advantageously greater than or equal to 99.9% by weight. 2. Method according to claim 1 characterized in that the molar ratio HF / 1,1,3,3-tetrachloropropene between 3 and 20, preferably between 5 and 15 and preferably between 9 and 12. 3. Method according to claim 1 or 2 characterized in that the temperature is between 50 and 150 ° C, preferably between 80 and 120 ° C and preferably between 90 and 110 ° C. 4. Method according to any one of the preceding claims characterized in that the pressure is 1 to 20 bar, preferably between 5 and 15 bar and preferably between 7 and 12 bar. 5. Process according to any one of the preceding claims, characterized in that the fluorination reaction is carried out in an unstirred reactor. 6. Process according to any one of the preceding claims, characterized in that the process is carried out continuously, discontinuously or batchwise, preferably continuously. 7. Method according to any one of the preceding claims, characterized in that at the end of step (iii) the stream D is subjected to a separation step to give a stream mainly comprising HF, which can be recycled to the reactor. 8. The method of claim 7 characterized in that the separation step is a settling preferably carried out between -50 and 50 ° C. 9. Method according to any one of the preceding claims characterized in that the treatment step (ii) is a reflux operation, preferably carried out between 30 and 120 ° C. 10. Process according to any one of the preceding claims, characterized in that the recovery step of HCl is carried out at a temperature of 20 to 110 ° G at the bottom of the boiler and -50 to 0 ° C at the head. 11. Process according to any one of the preceding claims, characterized in that the purification step (iv) comprises at least one azeotropic distillation. 12. Installation for the implementation of the method according to any one of the preceding claims. 13. Installation comprising a reactor 3 provided with at least two supply lines, with an effluent outlet connected to a reflux system 4, connected to an HCL recovery unit 6, said unit 6 being connected to a separation system 8 with the latter being connected to a purification system 12.