High purity 1,1,1,2,3,3-hexafluoropropane, its production method and its use

Abstract

The present invention relates to high purity 1,1,1,2,3,3-hexafluoropropane, its production method, and the use of compositions containing primarily 1,1,1,2,3,3-hexafluoropropane as cleaning agents in the semiconductor industry.

Description

[Technical field]

[0001] The present invention relates to high purity 1,1,1,2,3,3-hexafluoropropane, its production method, and the use of compositions based on this 1,1,1,2,3,3-hexafluoropropane as cleaning agents in the semiconductor industry. [Background technology]

[0002] 1,1,1,2,3,3-Hexafluoropropane (HFC-236ea) is a hydrofluorocarbon known as a raw material for producing 1,1,1,2,3-pentafluoropropene, or as an intermediate for producing 1,1,1,2,3-pentafluoropropane and / or 1,1,1,2-tetrafluoropene. For details, see [Patent Document 1] (U.S. Patent No. 5679875), [Patent Document 2] (U.S. Patent No. 539600), [Patent Document 3] (U.S. Patent No. 8359964), and [Patent Document 4] (U.S. Patent No. 8389779).

[0003] In particular, 1,1,1,2,3,3-hexafluoropropane can be produced by catalytic hydrogenation of hexafluoropropene.

[0004] It can also be produced by pyrolysis of chlorodifluoromethane (CHClF2) in the presence of 1,1,1,2-tetrafluoroethane at high temperatures. For more information, see [Patent Document 5] (International Publication No. WO1996029296).

[0005] Further, 1,1,1,2,3,3-hexafluoropropane can be produced by dechlorinating 1,1,1,2,2-pentafluoro-3,3-dichloropropane (HCFC-225ca) and / or 1,1,2,2,3-pentafluoro-1,3-dichloropropane (HCFC-225cb) with hydrogen in the presence of a catalyst comprising a metal oxide to produce at least one tetrafluorochloropropene, and then producing the resulting product ((1,1,1,2-tetrafluoropropene)). It can also be produced by a process in which tetrafluoro-3-chloro-2-propene (HCFO-1224yd), 1,1,2,3-tetrafluoro-1-chloro-2-propene (HCFO-1224ye) and 1,1,2,3-tetrafluoro-3-chloro-1-propene (HCFO-1224yc) are fluorinated in the presence of a catalyst to produce HFC-236ea. For more information, see [Patent Document 6] (U.S. Patent No. 5,532,418).

[0006] In [Patent Document 7] (U.S. Pat. No. 5,563,304), 1,2,3,3,3-pentafluoropropene (HFO-1225ye) is reacted with hydrogen fluoride at high temperature over a catalyst selected from the group consisting of aluminum fluoride, fluorinated aluminum oxide, metal fluoride supported on aluminum, metal fluoride supported on alumina, and trivalent chromium-containing catalyst to produce 1,1,1,2,3,3-hexafluoropropane. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] U.S. Patent No. 5,679,875 [Patent Document 2] U.S. Patent No. 539600 [Patent Document 3] U.S. Patent No. 8,359,964 [Patent Document 4] U.S. Patent No. 8,389,779 [Patent Document 5] International Publication No. WO1996029296 [Patent Document 6] U.S. Pat. No. 5,532,418 [Patent Document 7] U.S. Patent No. 5,563,304 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention provides a method for producing high purity 1,1,1,2,3,3-hexafluoropropane. [Means for solving the problem]

[0009] The process of the present invention involves providing a stream containing up to 99 weight percent 1,1,1,2,3,3-hexafluoropropane and then treating the stream to produce at least 99.4 weight percent HFC-236ea and up to 0.6 weight percent hexafluoropropene, cis / trans-1,2,3,3,3-pentafluoropropene (HFO-1225ye(Z / E)), 1,1,3,3,3-pentafluoropropene (HFO-1225ye(Z / E)), and 1,2,3,3,3-pentafluoropropene (HFO-1225ye(Z / E)). 5zc), 1,1,2,3,3-pentafluoropropene (HFO-1225yc), 2,3,3,3-tetrafluoropropene (HFO-1234yf), cis / trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(Z / E)), 3,3,3-trifluoropropene (HFO-1243zf), 1,1,1,2,3,3,3-pentafluoropropane (HFC-227ea), 1, 1,1,3,3,3-Hexafluoropropane (HFC-236fa), 1,1,1,3,3-Pentafluoropropane (HFC-245fa), 1,1,1,2,3-Pentafluoropropane (HFC-245eb), 1,1,1,2-Tetrafluoroethane (HFC-254eb), 1,1,1,3-Tetrafluoropropane (HFC-254fb), 1,1,1-Trifluoropropane (HFC-263 and at least one compound selected from the group consisting of 1,1,2-trifluoroethane (HFC-143), hexafluorocyclopropane (cycloC3F6), octafluorocyclobutane (cycloC4F8), cis / trans-1,1,1,4,4,4-hexafluoro-2-butene (HFO-356mff(Z / E)), water, hydrogen, nitrogen, oxygen, CO2, CO, and HF. The process includes at least one separation and / or purification step. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Said stream containing up to 99% by weight of 1,1,1,2,3,3-hexafluoropropane can be obtained by any process capable of producing 1,1,1,2,3,3-hexafluoropropane, but preferably it is obtained in a process for catalytic hydrogenation of hexafluoropropene.

[0011] The separation steps may include condensation, evaporation, decantation, absorption, washing, and liquid-liquid extraction.

[0012] Said purification step can be photochlorination, distillation, for example extractive distillation, azeotropic distillation, adsorption on solids, in particular on molecular sieves, alumina, activated carbon, and membrane separation.

[0013] A more specific subject of the present invention is a process for the production of 1,1,1,2,3,3-hexafluoropropane, comprising the following steps (i) and (ii): (i) Hexafluoropropene (HFP) is hydrogenated to produce 1,1,1,2,3,3-hexafluoropropane, optionally containing unreacted hexafluoropropene, unreacted hydrogen, cis / trans-1,2,3,3,3-pentafluoropropene (HFO-1225ye)(Z / E)), 1,1,3,3,3-pentafluoropropene (HFO-1225zc), 1,1,2,3,3-pentafluoropropene (HFO-1225zc), 1,1,2,3,3-pentafluoropropane ... 1,1,1,2,3,3,3-Tetrafluoropropene (HFO-1225yc), 2,3,3,3-Tetrafluoropropene (HFO-1234yf), cis / trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(Z / E)), 3,3,3-trifluoropropene (HFO-1243zf), 1,1,1,2,3,3,3-pentafluoropropane (HFC-227ea), 1,1,1,3,3,3 -Hexafluoropropane (HFC-236fa), 1,1,1,3,3-pentafluoropropane (HFC-245fa), 1,1,1,2,3-pentafluoropropane (HFC-245eb), 1,1,1,2-tetrafluoropropane (HFC-254eb), 1,1,1,3-tetrafluoropropane (HFC-254fb), 1,1,1,3-tetrafluoropropane (HFC- a stream further comprising 1,1,1-trifluoropropane (HFC-263fb), 1,1,2-trifluoroethane (HFC-143), hexafluorocyclopropane (cycloC3F6), octafluorocyclobutane (cycloC4F8), cis / trans-1,1,1,4,4,4-hexafluoro-2-butene (HFO-356mff(Z / E)), water and THF; (ii) subjecting said stream to at least one separation and / or purification step to obtain at least 99.4% by weight of HFC-236ea and at most 0.6% by weight of hexafluoropropene, cis / trans-1,2,3,3,3-pentafluoropropene (HFO-1225ye(Z / E)), 1,1,3,3,3-pentafluoropropene (HFO-1225zc), 1,1,2 ... 1,1,1,2,3,3,3-pentafluoropropene (HFO-1225yc), 2,3,3,3-tetrafluoropropene (HFO-1234yf), cis / trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(Z / E)), 3,3,3-trifluoropropene (HFO-1243zf), 1,1,1,2,3,3,3-pentafluoropropane (HFC-227ea), 1,1,1,3,3,3 -Hexafluoropropane (HFC-236fa), 1,1,1,3,3-pentafluoropropane (HFC-245fa), 1,1,1,2,3-pentafluoropropane (HFC-245eb), 1,1,1,2-tetrafluoropropane (HFC-254eb), 1,1,1,3-tetrafluoropropane (HFC-254fb), 1,1,1-trifluoropropane (HFC-263f b), 1,1,2-trifluoroethane (HFC-143), hexafluorocyclopropane (cycloC3F6), octafluorocyclobutane (cycloC4F8), (cis / trans)-1,1,1,4,4,4-hexafluoro-2-butene (HFO-356mff(Z / E)), water, hydrogen, nitrogen, oxygen, CO2, CO, and at least one compound selected from HF.

[0014] The separation and / or purification steps can be selected from: - adsorption, for example on activated alumina and / or molecular sieves; -distillation, -membrane separation, - Washing with water, -Photochlorination.

[0015] The above separation and / or purification steps may comprise at least one adsorption step, preferably on activated alumina and / or on molecular sieves, and at least one distillation step.

[0016] Preferably, said separation and / or purification steps include (a) at least one step of removing HF by adsorption on activated alumina or by membrane separation, and / or (b) at least one step of removing water by adsorption on molecular sieves with pore sizes of 3 Å and 5 Å, and / or (c) at least one distillation step.

[0017] Advantageously, said separation and / or purification steps include (a) at least one step for removing HF, (b) at least one step for removing water, and (c) at least one distillation step.

[0018] The distillation step (c) can be carried out by means of a distillation column in which the purified HFC-236ea is taken at the head of the column and the heavy compounds are recovered at the bottom of the column, or in which the light compounds are recovered at the top of the column, the purified HFC-236ea is withdrawn from the side of the column and the heavy compounds are recovered at the bottom of the column.

[0019] After completion of the distillation process, the HFC-236ea is purified in a final purification step (d) using molecular sieves having a pore size of 4 Å or greater.

[0020] The above distillation step (c) may be carried out at a pressure between 1 and 15 bar absolute, preferably between 3 and 10 bar absolute.

[0021] The distillation step (c) can be carried out using two distillation columns. The first can be used to remove light compounds such as HFP, HFO-1234yf, HFO-1243zf, HFO-1225ye(Z / E), HFO-1234ze(Z / E), HFO-1225zc, HFC-227ea, HFC-236fa, HFC-254eb, cyclo-HFP, and the second can be used to remove heavy compounds such as HFC-245fa, HFC-245eb, HFO-356mff(Z / E), HFC-254fb. The purified HFC-236ea is obtained at the top of the second distillation column. To save both capital and energy, these two distillation columns or a distillation column with a side stream can be advantageously replaced by a single dividing wall distillation column.

[0022] In another preferred embodiment, the removal of HF step (a) can be carried out by washing with water, optionally with a further washing with sodium hydroxide or potassium hydroxide solution to neutralize traces of residual acid.

[0023] In another preferred embodiment, the HF removal step (a) can be carried out in a step (a0) of photochlorination of the olefins present in HFC-236ea. In this case, it is preferred to remove not only HF in the HF removal step (a) but also to wash with an aqueous solution capable of absorbing the HCl formed by the photochlorination step and residual Cl2.

[0024] The above step (a0) can be carried out in the liquid or gas phase in a photochlorination reactor equipped with a lamp and a transparent window. A mixture of a stream containing chlorine and HFC-236ea containing unsaturated fluorinated products is introduced into the photochlorination reactor. The reaction is preferably carried out in the gas phase. The resulting stream containing HFC-236ea and chlorofluorinated saturated products is sent directly to the next purification step.

[0025] The above hydrogenation step is preferably carried out in the presence of a catalyst.

[0026] Examples of catalysts include metals such as Pd, Ru, Pt, Rh, Ir, Fe, Co, Ni, Cu, Ag, Re, Os, Au, Ge, Te, etc., which may be supported, and examples of supports include carbon, alumina, fluorinated alumina, AlF3, oxides, oxyfluorides and fluorides of Cr, Ti, Zr, Mg, Zn, silica, and silicon carbide.

[0027] In the case of a support, the amount of metal present in the catalyst can be 0.001 to 10% by weight, preferably 0.001 to 0.2% by weight.

[0028] The above hydrogenation step is advantageously carried out in the presence of Pd supported on alumina, preferably Pd in ​​the alpha polymorph form.

[0029] The hydrogenation step described above can be carried out in either the gas or liquid phase, although the gas phase is preferred.

[0030] The hydrogenation step is preferably carried out in the presence of hydrogen, preferably at a hydrogen / hexafluoropropene molar ratio of 1-50, particularly preferably 2-15.

[0031] The hydrogenation step is preferably carried out at a temperature between 50 and 200°C, preferably between 80 and 120°C.

[0032] The temperature at the reactor inlet in the hydrogenation step is 30 to 100°C, preferably 40 to 80°C. It is preferable to place the ion exchange resin between 0.1 and 0.2 mm.

[0033] Overall under standard conditions cumulative flow The contact time of the hydrogenation step, defined as the ratio of the volume of the catalyst bed to the amount of the catalyst, is preferably between 0.1 and 20 seconds, advantageously between 0.5 and 5 seconds.

[0034] The hydrogenation step is preferably carried out at an absolute pressure ranging from 0.5 to 20 bar absolute, advantageously from 1 to 5 bar absolute.

[0035] The hydrogenation step is preferably carried out in the presence of a diluent, which may be fed together with the reactants in the reaction medium. The diluent is an inert gas that does not react under the conditions of the hydrogenation step. The diluent may include nitrogen, helium or argon.

[0036] The diluent / reactant molar ratio at the reactor inlet of the hydrogenation step can be between 100:1 and 1:1, preferably between 10:1 and 1:1, advantageously between 5:1 and 1:1.

[0037] The diluent may be a hydrogenated version of HFC-236ea, in which case a portion of the gas stream leaving the reactor containing HFC-236ea and unreacted hydrogen, and possibly also unreacted hexafluoropropene, 1,1,1,2,3-pentafluoropropane (HFC-245eb) and 1,1,1,2-tetrafluoroethane (HFC-254eb), is recycled and another portion of the gas effluent from the reactor is sent to a separation and / or purification step.

[0038] The gas streams and reactants comprising the recycle loop may be preheated prior to being introduced into the reactor.

[0039] It is preferred to use an adiabatic reactor in the process of the present invention.

[0040] Advantageously, the portion of said gas stream recycled to the reactor is at least 90% by volume, preferably at least 93% by volume, of the total volume of effluent at the reactor outlet, more preferably the portion of said effluent recycled to the reactor is between 94 and 98% by volume of the total volume of effluent at the reactor outlet.

[0041] The stream at the end of the hydrogenation step can be sent to a condensation step, in which case it is condensed under conditions such that the unreacted hydrogen is not condensed, but rather a part of the HFC-236ea formed in step (i) is condensed. The condensation step is preferably carried out at a temperature between 0 and 50° C. and at a pressure between 0.5 and 20 bar absolute, preferably between 1 and 5 bar absolute.

[0042] The condensation step is preferably carried out under conditions such that from 1 to 30% by weight, advantageously from 2 to 10%, of the HFC-236ea leaving the reactor is condensed.

[0043] The non-condensable fraction is recycled, optionally after heating, to the hydrogenation step (i).

[0044] The condensed fraction is then evaporated and sent to the separation and / or purification steps described above.

[0045] During the hydrogenation reaction, carbon-fluorine cleavage can be observed to occur resulting in the formation of small amounts of HF, which is harmful in the use of HFC-236ea in the semiconductor industry.

[0046] The separated stream after step (i) is a stream containing primarily HFC-236ea, which is subjected to at least one washing step to reduce the HF content, however, the presence of residual water renders it unsuitable for use in the semiconductor industry.

[0047] The present invention further relates to a process for the preparation of a fluorocarbon fluoride-containing fluorocarbon polymer comprising at least 99.4% by weight of HFC-236ea and at most 0.6% by weight of hexafluoropropene, cis / trans-1,2,3,3,3-pentafluoropropene (HFO-1225ye(Z / E)), 1,1,3,3,3-pentafluoropropene (HFO-1225zc), 1,1,2,3,3-pentafluoropropene (HFO-1225yc), 2,3,3-di ... ,3,3,3-Tetrafluoropropene (HFO-1234yf), cis / trans-1,3,3,3-tetrafluoropropene (HFO-1234ze (Z / E)), 3,3,3-trifluoropropane (HFO-1243zf), 1,1,1,2,3,3,3-pentafluoropropane (HFC-227ea), 1,1,1,3,3,3-hexafluoropropane (HFC-236f a), 1,1,1,3,3-pentafluoropropane (HFC-245fa), 1,1,1,2,3-pentafluoropropane (HFC-245eb), 1,1,1,2-tetrafluoropropane (HFC-254eb), 1,1,1,3-tetrafluoropropane (HFC-254fb), 1,1,1-trifluoroethane (HFC-263fb), 1,1,2-trifluoropropane (HFC-143), hexafluorocyclopropane (cycloCF), octafluorocyclobutane (cycloCF), cis / trans-1,1,1,4,4,4-hexafluoro-2-butene (HFO-356mff(Z / E)), hydrogen, nitrogen, oxygen, CO, CO and HF,

[0049] HFC-236ea is preferably present in the composition in an amount of at least 99.9% by weight, advantageously at least 99.99% by weight, or even better at least 99.995% by weight.

[0050] In one embodiment of the invention, the composition comprises at least 99.9% by weight, advantageously at least 99.99% by weight, even more advantageously at least 99.995% by weight of HFC-236ea and at most 0.1% by weight, preferably at most 1 ppm, advantageously at most 0.1 ppm of HF.

[0051] In one embodiment of the invention, the composition comprises at least 99.4% by weight, preferably 99.9% by weight, advantageously 99.99% by weight or even 99.995% by weight of HFC-236ea and at most 190 ppm, preferably at most 10 ppm, advantageously at most 1 ppm of water.

[0052] In one embodiment of the invention, the composition comprises at least 99.4% by weight, preferably 99.9% by weight, preferably 99.99% by weight or even 99.995% by weight of HFC-236ea and at most 5 ppm, preferably at most 1 ppm, preferably at most 0.3 ppm, advantageously at most 0.1 ppm of hydrogen.

[0053] In one embodiment of the invention the composition comprises at least 99.4% by weight, preferably 99.99% by weight, more preferably 99.995% by weight of HFC-236ea and at most 3500 ppm, preferably at most 150 ppm, more preferably at most 70 ppm, advantageously at most 5 ppm of nitrogen.

[0054] In one embodiment of the invention the composition comprises at least 99.4% by weight of HFC-236ea, preferably 99.99% by weight, more preferably 99.995% by weight, and at most 1000 ppm, preferably at most 20 ppm, more preferably at most 10 ppm, advantageously at most 2 ppm of oxygen.

[0055] In one embodiment of the invention, the composition comprises at least 99.4% by weight, preferably 99.99% by weight, more preferably 99.995% by weight of HFC-236ea and at most 125 ppm, preferably at most 20 ppm, more preferably at most 5 ppm, advantageously at most 2 ppm of CO2.

[0056] In one embodiment of the invention, the composition comprises at least 99.4% by weight, preferably 99.99% by weight, more preferably 99.995% by weight of HFC-236ea and at most 90 ppm, preferably at most 15 ppm, more preferably at most 3 ppm, advantageously at most 1.5 ppm of CO.

[0057] In one preferred embodiment of the invention, the composition comprises at least 99.4% by weight, preferably 99.99% by weight, more preferably 99.995% by weight of HFC-236ea, at most 190 ppm of water and at most 0.1% by weight of HF, preferably at most 10 ppm of water and at most 1% by weight of HF, advantageously at most 1 ppm of water and at most 0.1% by weight of HF.

[0058] In any embodiment, the composition of the invention comprises at most 1000 ppm, preferably at most 100 ppm, advantageously at most 10 ppm of at least one compound selected from hexafluoropropene, cis / trans-1,2,3,3,3-pentafluoropropene ((Z / E) of HFO-1225ye), 1,1,1,3,3,3-pentafluoropropene (HFO-1225zc), 1,1,2,3,3-pentafluoropropene (HFO-1225yc) and 3,3,3-trifluoropropene (HFO-1243zf) and at most 5000 ppm, preferably at most 500 ppm, advantageously at most 50 ppm of at least one compound selected from hexafluorocyclopropane (cycloCF6) and octafluorocyclobutane (cycloCF8).

[0059] In either embodiment, the composition of the present invention contains at most 6000 ppm, preferably at most 3000 ppm, advantageously at most 100 ppm of total organic impurities. EXAMPLES

[0060] Experimental part Test 1 325 g of about 97.8 wt % HFC-236ea (previously washed) was placed in a jacketed glass distillation apparatus (cooled to -20°C) with an "Oldershaw" jacket with about 10 theoretical plates and fitted with a reflux condenser. The mixture had the following composition:

[0061] [Table 1]

[0062] The distillation was carried out at atmospheric pressure. A total of 12 fractions were collected at a head temperature of 10°C.

[0063] [Table 2]

[0064] Fractions with purity >99.7% were pooled and dried by passage through 4 Å molecular sieves to form the final batch.

[0065] Analysis of this final lot revealed a purity of >99.7% by weight HFC-236ea, llppm water, and no detectable traces of acid. Ta.

[0066] Test 2 A gas stream containing 99.8 wt. % HFC-236ea, 217 ppm HF, and 27 ppm water was passed through a bed of BASF HF-200 alumina spheres (1 / 8" spheres) (length / diameter ratio = 10) and a bed of siliporite molecular sieves (pore size = 3 Å) at room temperature for 8 hours. The resulting stream at the output is nearly free of HF and water (HF<1 ppm, water 10 ppm).

Claims

1. A method for producing high purity 1,1,1,2,3,3-hexafluoropropane, comprising the following steps (i) and (ii): (i) providing a stream comprising at most 99 wt. % 1,1,1,2,3,3-hexafluoropropane; (ii) subjecting said stream to purification treatment selected from distillation and molecular sieves to obtain at least 99.4 wt. % HFC-236ea and at most 0.6 wt. % of hexafluoropropene, cis / trans-1,2,3,3,3-pentafluoropropene (HFO-1225ye(Z / E)), 1,1,3,3,3-pentafluoropropene (HFO-1225zc), 1,1,2,3,3-pentafluoropropene (HFO-1225yc), 2,3,3,3-tetrafluoropropene (HFO-1234yf), cis / trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(Z / E)), 3,3,3-trifluoropropene (HFO-1234ze(Z / E)), 4,4,5-trifluoropropene (HFO-1234ze(Z / E)), 5,6,7-trifluoropropene (HFO-1234ze(Z / E)), 6,8,9-trifluoropropene (HFO-1234ze(Z / E)), 7,9,10-trifluoropropene (HFO-1234ze(Z / E)), 8,10,10-trifluoropropene (HFO-1234ze(Z / E)), 9,10,10-trifluoropropene (HFO-1234ze(Z / E)), 11, ... 1,1,1,2,3,3,3-heptafluoropropene (HFC-227ea), 1,1,1,3,3,3-hexafluoropropane (HFC-236fa), 1,1,1,2,3-pentafluoropropane (HFC-245eb), 1,1,1,3,3-pentafluoropropane (HFC-245fa), 1,1,1,2-tetrafluoropropane (HFC-254eb), 1,1,1,3-tetrafluoropropane (HFC-254fb), 1,1,1-trifluoropropane (HFC-263fb), 1,1,2-trifluoroethane (HFC-143), hexafluorocyclopropane (cycloC 3 F 6 ), octafluorocyclobutane (cyclo C 4 F 8 ), cis / trans-1,1,1,4,4,4-hexafluoro-2-butene (HFO-356mff(Z / E)), water, hydrogen, nitrogen, oxygen, CO 2 and at least one compound selected from the group consisting of CO and HF; The purification of said stream comprises washing said stream containing up to 99 wt. % 1,1,1,2,3,3-hexafluoropropane with water, distilling the washed stream, pooling fractions having a purity of >99.7% and passing the pooled fraction through a 4 Å molecular sieve, wherein the final batch obtained after treatment has a purity of >99.7 wt. % HFC-236ea, a water content of 11 ppm or less and no detectable traces of acid.

2. The method according to claim 1, comprising the steps of: (i) Hexafluoropropene is catalytically hydrogenated to produce 1,1,1,2,3,3-hexafluoropropane, which further contains unreacted hexafluoropropene, unreacted hydrogen, cis / trans-1,2,3,3,3-pentafluoropropene (HFO-1225ye(Z / E)), 1,1,3,3,3-pentafluoropropene (HFO-1225zc), 1,1,2,3,3-pentafluoropropene (HFO-1225yc), 2,3,3,3-tetrafluoropropene (HFO-1234yf), cis / trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(Z / E)), 3,3,3-trifluoropropene (HFO-1234ze(Z / E)), and the like. FO-1243zf), 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), 1,1,1,3,3,3-hexafluoropropane (HFC-236fa), 1,1,1,3,3-pentafluoropropane (HFC-245fa), 1,1,1,2,3-pentafluoropropane (HFC-245eb), 1,1,1,2-tetrafluoropropane (HFC-254eb), 1,1,1,3-tetrafluoropropane (HFC-254fb), 1,1,1-trifluoropropane (HFC-263fb), 1,1,2-trifluoroethane (HFC-143), hexafluorocyclopropane (cyclo-C 3 F 6 ), octafluorocyclobutane) (cycloC 4 F 8 ), cis / trans-1,1,1,4,4,4-hexafluoro-2-butene (HFO-356mff(Z / E)), water, nitrogen, oxygen, CO 2 providing a stream comprising at least one compound selected from CO and HF; (ii) subjecting said stream to purification treatment selected from distillation and molecular sieves to obtain at least 99.4 wt. % HFC-236ea and at most 0.6 wt. % of hexafluoropropene, cis / trans-1,2,3,3,3-pentafluoropropene (HFO-1225ye(Z / E)), 1,1,3,3,3-pentafluoropropene (HFO-1225zc), 1,1,2,3,3-pentafluoropropene (HFO-1225yc), 2,3,3,3-tetrafluoropropene (HFO-1234yf), cis / trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(Z / E)), 3,3,3-trifluoropropene (HFO-1234ze(Z / E)), 4,4,5-trifluoropropene (HFO-1234ze(Z / E)), 5,6,7-trifluoropropene (HFO-1234ze(Z / E)), 6,8,9-trifluoropropene (HFO-1234ze(Z / E)), 7,9,10-trifluoropropene (HFO-1234ze(Z / E)), 8,10,10-trifluoropropene (HFO-1234ze(Z / E)), 9,10,10-trifluoropropene (HFO-1234ze(Z / E)), 11, ... 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), 1,1,1,3,3-pentafluoropropane (HFC-245fa), 1,1,1,3,3,3-hexafluoropropane (HFC-236fa), 1,1,1,2,3-pentafluoropropane (HFC-245eb), 1,1,1,2-tetrafluoropropane (HFC-254eb), 1,1,1,3-tetrafluoropropane (HFC-254fb), 1,1,1-trifluoropropane (HFC-263fb), 1,1,2-trifluoroethane (HFC-143), hexafluorocyclopropane (cycloC 3 F 6 ), octafluorocyclobutane (cyclo C 4 F 8 ), cis / trans-1,1,1,4,4,4-hexafluoro-2-butene (HFO-356mff(Z / E)), water, nitrogen, oxygen, CO 2 and at least one compound selected from the group consisting of CO and HF.

Images