AZEOTROPIC OR AZEOTROPIC-LSKE COMPOSITIONS OF 1,1,1- TRfFLUGR ^Q ETHAME AND 1-CHLORO-2,2,2-TRIFLUOROETHANE

Fie'd of the insertion

[0001] T ¹ I ¹ S irventicn relates to compositions of 1 1 1-tπfluoroethaπe (HFC-

143a; ana more specif ^! cahy to azeotropsc ana azeoτropic->ικe compositions of 1 1 1- tπfiuoroethaπe arα i-chlorQ-2 2 2-tπf!uoroethane (R-133a)

Background to the Invention

[0002] A numoe, o ^r processes for the production oτ 1 1 i-trifiuoroethane

(HFC-i43a) are known "-icwever, the proαucts of these processes contain reaction by-products among wn^ch §s 1-chloro-2,2 2-tnfiuoroethaπe _x R-133a) it is highly desirab'e tc oe aoie tc ^" eπcve sdcn reaction Dy-ρ ^r odjcts in orαer to achieve purer 1 1 1-iπfiϋoroethane o ^r ε 1 1 ^'' -t^fiuo'-oethane comcosstions Having a boiling point within a reiaisveiy small range

[00031 Unfortunately as is known tαthose in the relevant art the comomation of twc cr rnoie constituents ^f orming an HFCφon-riFC msxture often resuits in compositors wheresr relatives^ sma'i changes in trie relative amounts of the constituents results in -eiatively large cnanges sη the boiling point and vapor pressure of ^f hs ^η xtϋre Fo exarpple tne boding point and vapor pressure characteπsυcs of ran _r r pica HFCnoπ-riF3 msxtures can oe predicted us^ng Regular Sc ¹ Ut(Oi nratheiratica ¹ "lodete as αescnoed 'n Praunit∑ Lichteπthaier Azeveαc iviotecj ⁱ a ^{^ "} ^eTnoαv ^r anmcs ^{•" ρ} lϋic-Phase Equilibria pp 179-19C seccnα βd ύcr i ^D ^era..ce-ήBt ^*~ z ιncorρo ^r a ^* ec ^erein DV 'eference thereto As ji'ust ^r stec t ^{c ~} aus ^r nz e. a a ρso ^ι cf ^aoo" pressure c Dci'tng posnt of a regular solution v'e^i-s ι: s oonstnuent compcsitic, teres tc ηave a s ^! gnrficantSy oosrtive SiCpe r^at.ic ^a ₁ eia ^í t eiv a^ge changes .r \ apo ^r pressu ^r e or bomπg pom* occur upon -e.a'^vei^ s"ial< cha ⁿ ges r "e const'tϋen; COπDOSITΌγ /^ccord'ngly mixtures 'ia\ irc C T e ε e ~ ^" 5 c re ^e" :eε " εcsts ^r u6 ^* "ιτ amounts may stiP have

relatively large changes in boiling points. Thus there is a need to identify a binary azeotropic or azeotropic-like mixture of HFC-143a and R-133a so thai modeling ana simulation may be accomplished to identify the correct necessary separation equipment and methods to better obtain puπtses of final HFC-I43a product

Summary of tfte Invention

|0004] Applicants have come to appreciate that mixtures having a relatively constant boiling point, that is. a boding point that changes Dy a relatively small ic amount as the constituent amounts of the mixture changes are difficult to separaxe.

(Deleted texts as we are not focusing on spraying applications but on separation process by distillation; Unfortunately, mixtures having such relatively constant boiling point properties are not only uncommon, but also unpredictable.

s [0005] The present inventors have discovered azeotropic or azeotropic-like compositions of effective amounts of 1 1 ,1-trifluorcethane (HFC-143a) and 1-ciiloro- 2,2,2-trifluoroethane (R-133a) The discovery of the azeotropic or azeotropiolike compositions of HFC-143a and R~133a permits such azeotropic or azβtropsc-ϋke compos _ϊ iions to be distilled off from a composition containing both HFC-143a and R- ₀ 133a in a distillation column whereby the concentration of R-133a at the fop of the column is greater than the concentration of R-133a in trie ootiom of the column. This distillation process has particular applicability in purifying HFC-143a when if is produced from the reaction of viπyπdene chioπαe with HF since the azeotropic or azeotropic-like compositions of HFC-I43a and R-i 33a can De distilled from the ₅ products of that reaction ,r, crαer io puπfy the HFC- "^Sa p-Oduceα

Defaced Description of the Invention

[00061 sr accorcance with the present inve ⁿ tion it nas peen discoverec that _C there are azeotropic or azeotropc-lικe composmcnε of effective amounts of "' ^■ A A- t ^r f!uoroeth8ne . HFC -I^Sa anc . -chιco-2 2,2-/" ^* ! jcroetnane ^« R-133a) ^{" •"} .e

discovery of the azeotropic or azeotropic-ϋke compositions of HFC-143a and R-133a permits such azeotropic or azeotropic-like compositions to be distilled off from a composition containing both HFC-143a and R- 133a in a distillation column whereby the concentration cf R-133a at the top of the column is greater than the concentration of R-133a in the bottom of the column. This distillation process has particular applicability in purifying HFC-143a when it m produced from the reaction of vinylidene chloride with HF since the azeotropic or azeofropic-lϊke compositions of HFC-143a and R-133a can be distilled from the products of that reaction in order to purify the HFO143a produced. The azeotropic or azeotropϊc-like composition of HFC-143a and R-133a from the top of the column can be recycled or sent back to the reactor for conversion of R-133a to HFC-143a.

[0007] It has been further discovered trial HFC-143a and R-133a form azeotropic or azeotroplc-iike compositions naving a boiling point with a relatively small range of -4δ.5±2 ⁰ C at atmospheric pressure (14.42 psia). Sn a further embodiment, the azeotrcpic or azeotropic-itke compositions have a boiling point of from about -46.6 to about -47,2 ⁰ C. In a still further embodiment the a∑eotroptc or azeotropic-like compositions have a boiling point of from about -46.8 ⁰ C to about - 47.2 ⁰ C. in a yet further embodiment the azeotropic or azeotropic-iike compositions have a boiling point of from about -47 ⁰ C to abcut -47.2 ⁰ C. in another still further embodiment, the azeotropic or azeotropic-ϋke compositions have a boiling point of about -47.2 ⁰ C.

[00081 Such azeotropfc or a∑eotropic-liκe compositions generally are mixtures of HFC-143s and R-133ε wherein the composition comprises, and preferably consists essentially of: from about 70% weight up tc an a-neusit just ϊess than about 100% by weight of HFC-1433. and from about 30 ^c /c Dy weight down to an srπcum just more than 0% by weight of

R-I 33a. wherein the weight percentages are based on lie ictεf weight of the composition,

[0009] In a further embodiment of the invention the azeoiropic or azeotropic- like compositions generally are mixtures of HFC-143a and P-133a wherein the composition comprises, and preferably consists essentially of, from about 75% by weighi up to a&oui 99.9% by weight of riFC-143a, and from about 0.1 % by weight ϊO about 25% by weight of R- 133a, wherein the weight percentages are based on the total weight of the composition. The azeotropic or azeotrαpic-iike composition of HFC-143a and R-133a from the top of the column can be recycled or sent Dack to the reactor for conversion of R-183a to HFC-143a,

[0010] in a still further embodiment of the invention the azeotropic or azeoirop?c-lϊke compositions generally are mixtures of HFC-143a and R-133a wherein the composition comprises and preferably consists essentially of from about 90% by weight up to about 99 9% by weight of HFC-143a, and from about 0 1 % by weight to about 10% by weight R-133a wherein the weight percentages are based on the total weight of the composition. The azeotropic or azeotropic-ϋke composition of HFC~143a and R-133a from the top of the column can be recycled or sent back to the reactor for conversion of R-133a to HFC-1433.

[0011] The inventors have also discovered that during a distillation process involving 143a and 133a mixtures the 133a wil. tend to accumulate in the upper, cooier part of the column, up ic the azeotropic composition, instead of the bottom warmer part o ^f the column This oropert, may ce <jsec ic remove the ¹ SSa, the undesirable comconeni from tr.e mixtjre as the pure 1^3a having a boiling point higher than of ϊhe azeoirope >#si> lend ϊC accumulate «n the bottom of the column from where it car- oe extracteα. THUS, ε distillation ρ ^r ocess of this invention win cor.pπse aisti^nc s ^1" azectrep«c c 3zectrcp,o,sκe H ^c C-l43a/HCFC-' ^" 3Sa

composition and as a result of the distillation the 183a concentration on the top of the column Is higher than the 133a concentration in the composition in the bottom of the column. In accordance with an embodiment of the invention the azetropic or azetropic-lske compositions being distilled εre azeotropsc or azeotropic-iike compositions cf effective amounts of 1.1, 1-trifluoroethane (HFC-143a) and i-chioro- 2,2,2-trifluoroethane (R- 133a). If has further been discovered that HFC»143a and R- 133a form azeotropic or azeotropsc-ϊike compositions being distilled may have a boiling point with a relatively smaiϊ range of -48.5±2 ⁰ C at atmospheric pressure (14.42 psia). In a further embodiment, the azeotropic or azeotropic-like compositions being distilled have a boiling point of from about -46.6 to about -47.2 ⁰ C. in a still further emoodiment, the azeotropic or azeotropic-iike compositions being distilled have a boiling point of from about -46.8 ⁰ C to about -47.2 ⁰ C, In a yet further embodiment the azeotropic or azeotropic-like compositions being distilled have a boiling posm of T ^' γCF ¹ about -47 ⁰ C to about -47.2 ⁰ C. in another stifi further embodiment the azeotropic or azeotropic-like compositions being distilled have a ing point of aboϋϊ -47.2 ⁰ C.

_{ιuu l tj} In the distillation process, the azeotropϊc or azeotropic-ϋke compositions generally are mixtures of HFC-143a and R-133a wherein the composition comprises, and preferably consists essentiaily of: from about 70% by weight up to an amount just less than about 100% by weight Of H FC- 143a and from about 30% Dy weight down to an amount just more than 0% by weight of R-133a wherein toe weight oe-xentages are based on the toia! weight of the composition.

ιO013] h ε further emDod'rr.eπt of tne invention, in the distillation process, the azeotropic or azeoircpic-iike compositions generally are mixtures of HFC-143a and R-133a wherein tne Gcmocsiiio ^1" - comprises, anc preferably consists essentially of: from abou: 7£% oy weight up to about 9S.9% by weight of HFG-143a, arc

from about 0 1 % by weight ;o aoout 25% by weight of R-" 33a wherein the weight percentages are based on τhe total weight Q* ⁺ he composition

[00143 In a stilt further embodiment of the invention in the distillation process

5 the azeotropic or azeotropic-ltke compositions generally are nuxtures of HFC- ¹ 143a and R-133a wherein the composition composes and preferably consists essential of from about 90% by weight up to about 99 9% by weight of hFC-143a and io from about 0 1 % Dy weight to aoout 10% by weignt of R- 133a, wherein the we;ght perceπiages a ^r e based on tne tola! weigh! of the composition

[0015] The invention wsil be paracuiariy useful *heπ HFC-143a is produced by the reaction of vinylidene chlcnαe witπ ^F and the reaction product contains HFO j.5 143 a and R-133a since the afore-mentroned distillation process may be conducted on the products of that reaction to distill off from the products of that reaction any of the azeotropc or azeofropic-like compositions as described herein before in order to purify the HFC-143a product produced

20 [0016] Tbjs invention provides azeoptropic or azeoptrop>c-i"ke compositions of

HFC-143a and R-133a Having a boiling point with a relatively small range of ±2 ⁰ C at atmospheric pressure ^14 42 psia) Such azeotropic or azeotroρic-iiκe compositions generally are mixtures of HFC-143a and R- ¹ 33a wherein ^* hβ composition comprises and preferably consists essentially cf z, _^ from about 70% b> v^eight uc to ar amount sust less tia ¹ " aboui 100% Dy weight of and from aocjT 3C"-c fov weight αo/ r tc ar aTOdiii LSϊ mere iπan 0°/c DV weigh P~133a wherein iπe wesc^t pe ^r ceρtages a"e tasec o^ t-e τoϊai weigh" c ^{* +} he oomposraoi ^* z. Such compcsϋϊcns Ai-n, ha^e a bo ^s8 sηg DOψI ai atmosorier.c oressure {14 42 pssa' WITπIπ the ^r β'ai βs ε ^* ^a range c ™*~t cr2 -Z F- ^" eτeτeo 3c ^~ ipos«tions ot tmε

inventior are those consisting essentially of about /5% to about 99% by weight of HFC-143 ₃ and from about 1 % to about 25% by weight of R-133a and having a boiling point at atmospheric pressure of about -46.5r2 ⁰ C. More preferred compositions of this invention are those consisting essentially of about 90% to about ₅ 99% by weight of HFC-143a and from about 1 % to abouϊ 10% by weight of R-133a and having a boiling point at atmospheric pressure of about -46.5±2 ⁰ C,

[0017] Because the normal boiling points of pure HFG-143a and R-133a at 1 atmosphere pressure are -47 ⁰ C and 8 ⁰ C. respectively, R-133a would be expected :c to be removed as the residue, or bottoms product, in a distillation of a HFC-143a and FM 33a mixture.

[0018] A further aspect of this invention is 8 process for removing 1-chforo-

2,2,2-triftuoroethane < R-133a; impurity from a mixture i 1 , 1 -trifiuoroethane (HFC- ₅ 143a) ana R-133a impurity comprising forming an azeotropic or azβotrope-like composition of the HFC-143a and R-133a. as described herein before, and thereafter separating the azeotropic or azeotrope-Nke composition from the mixture.

[0019] As shown in Table 1 the binary azeoirope or azeotrope-iike mixture c 143a/133a was discovered when tne higher boiling point 133a (-6 ⁰ C) was added to 143a (-46.5 ⁰ C). The temperature of the mixture is lower than the boiling temperature of eittier pure components. The azeotropic or azeotropic-like compositions of this invention are illustrated by but not iimited to, the following examples in Tabie 1 of compositions having a boiling point within the range of - 5 46.5-2 ⁰ C.

Table i

Wt ⁰ '= 1-^0-14Ss Wf% R-133s . Boiling point at

¹ atmospnerϊc

: pressure ⁰ C

[0020] Having described the invention in detail by reference to the preferred embodiments and specific examples thereof it wii! be apparent that modifications and variations are possible without departing from the spirit and scope of the disclosure and claims.

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