Nov. 19, l1946. G. à. LAKE 2,411,437 i RECOVERY 0F AQUEOUS AZEOTROPE FORMER IN OZEOTROPIC DISTILLATION OF HYDROCARBONS Filed Oct. 18, 1941 2 Sheets-Sheet 2 Y V o/snL/.maN „ze-¿mane meme? mvo scr/.VENT Eme/:mow f HZEOÍWE ‘ FORMER H 'Genga E fahr, > INVENTOR Patented Nov. 19, 1946 ' 2,411,437` 2,411,437 . RECOVERY OF AQUEOUS AZEOTROPE FORMER IN AZEOTROPIC DISTILLA TION OF HYDROCARBON S George R. Lake, Long Beach Calif., assignor to Union Oil Company of California, Los Angeles, Calif., a corporation of California Application October 18, 1941, Serial No. 415,568 8 Claims. (Cl. 202-42) l . 2 . with water since in many cases, the azeotrope tropic distillation to prepare pure hydrocarbons former has a preferential solubility in the hydro carbons as compared with the solubility in the from complex petroleum fractions'which are difii water. «The result is that the hydrocarbons must cult to separate by ordinary fractional distillation due to the small differences in boiling points of Si be, washed with an excessively large amount of the hydrocarbons contained in the petroleum water in order to remove the last traces of the ` azeotrope former so that the hydrocarbons may fraction. The invention is particularly directed to an improved process for separating `the hydro be utilized and the azeotrope former recoveredV without sustaining a substantial loss of this more carbons and the azeotrope former that are con tained in the azeotropic distillate produced by the valuable material. To illustrate, it has been found ‘ This invention relates to a process of azeo azeotropic distillation. that methyl ethyl ketone containing'water, i. e., The process of separating one hydrocarbon component from another hydrocarbon component about 10% by volume, is very efficient as an azeo-v trope former to effect the separation of non-aro Yof substantially the same boiling point contained , matic hydrocarbons from a hydrocarbon fraction 1 in a complex hydrocarbon fraction by azeotropic l. containing toluene. y Yet‘the use of this azeotrope former offers the serious difficulty of recovering distillationY is Well known. This process consists the methyl ethyl ketone from the azeotropic dis in distilling the hydrocarbon fraction in the pres tillate. While the separation of` the methyl ethyl ence of an extraneous substance which has a pref ketone may be accomplished by washing with erential afllnity for one of the components con water, this has required about ñve or six volumes tained in the complex hydrocarbon fraction, thus of water for each volume of azeotropic distillate. causing a disturbance of the vapor pressure equi Furthermore, in order to recover' the methyl ethy1 librium that formerly existed in the fraction in ‘ ketone from the veiy dilute wash solution, it is such manner that the partial vapor pressure or l fugacity of at least one component in the fraction necessary to heat an excessively large volume of is changed sumciently to permit its separation by dilute methyl ethyl ketone. _ separation of the azeotrope former containing relatively more paraliinic hydrocarbons together water `as a constituent from the hydrocarbons contained in the vazeotropic .distillate and it is a ` with the extraneous substance leaving as undis tilledbottoms the relatively less parafl‘lnic hydro ` It is thus an object of my invention to effect a controlled fractional distillation. In such proc esses, the distillation effects the separation of the 30 particular object to effect the aforesaid separa carbons which may or may not contain a portion of the extraneous substance. In the present de scription of my invention, the aforesaid type of fractional distillation will be referred to as azeo tropic distillation, the extraneous substance `or substances which are added to the complex hydro carbon fraction to effect the aforementioned change will be referred to as azeotrope formers and the overhead from the azeotropic distillation . will be referred to as the azeotropic distillate. tion in an efficient and economical manner. Itis a further object of my invention to effect the separation of the aqueous azeotrope former from` the'azeotropic distillate by ñrst removing . the Water contained in the azeotropic distillate ' and then subjecting the dried‘azeotropic distillate to fractional distillation to remove the azeotrope former from the hydrocarbons. A further objectÄ is to effect the fractional distillation of the dried azeotropic distillate under temperature and pres >One of` the main diiîiculties in the azeotropic sure conditions which are different than those of distillation process is in the separation or recovery ‘ the azeotropic distillation resulting in the produc of -the azeotrope former from the hydrocarbons contained in the azeotrope distillate. One of the f tion of the azeotropic distillate.' _ methods proposed for this purpose resides in washing the azeotropic distillate with water which l is adapted to dissolve the azeotrope former from the azeotropic distillate and thus be separated from the hydrocarbons by settling and stratifica V , I have discovered that if the water contained in 1an .azeotropic distillate which is produced by dis tilling a complex hydrocarbon fraction in the presence of an aqueous azeotrope former is re moved from the azeotropic distillate, the latter may then be fractionally distilled `and the re tion. The solution of azeotrope former and water 50 maining non-aqueous azeotrope former may be » effectively separated from the hydrocarbons, may be distilled to separate the azeotrope former whereas if the fractional distillation-is carried from the water. l out without removing the aqueous portion of the However, difllculty has been experienced to sep azeotrope former, an azeotrope consisting of the arate the azeotrope former substantially com aqueous azeotrope former and hydrocarbons will pletely from the azeotropic distillate by washing I 2,411,437 4 be distilled inthe same mannerand composition _ be removed by settling, centrifuging >or dilterlng as the azeotropic distillate was removed in the the chilled mixture.` initial azeotropic" distillation. However, by first . dehydra'ting the azeotropic distillate, the compo sitiòn of the remaining azeotropic distillate is ' modified suñlciently with respect to the partial , ' » In general, the passage of the azeotropic'distil late through the dehydrating agent is continued until the dehydrating agent is saturated with water and is no longer ’effective for removing fur vapor pressure of the constituents therein so that subsequent fractional distillation will prevent an azeotrope from distilling over and thus a separa tion of the azeotrope former from the hydrocar 10 is regenerated. bons may be accomplished. regeneration is accomplished by blowing a heat ' . - In other words, it has been found that; certain ' compounds are very veiiicient azeotrope'formers ther quantities of the ' water, whereupon the stream of azeotropic distillate is diverted toa fresh drier and the saturated dehydrating agent In the case of solid absorbents, ing gas, such as steam, air or inert gas through _the drier containing -the dehydrating agent until for the vseparation of“ hydrocarbons when em all of the water has been distilled from the de ployed in the 'absence of water, whereas other 15' hydrating agent. In the case "of the normally . compounds are very eñicient only in the presence liquid absorbent, regeneration maybe similarly -of water to effect the desired separation and when employed in the absence of water merely distill accomplished or the saturated dehydrating agent may be fractionally distilled at a temperature> from'the hydrocarbon mixture without taking, » above the boiling point of water asis well known any of the hydrocarbon components overhead. 20 by those skilled in the art. Where solid dehy Hence, when an azeotropic distillate which is pro drating agents are employed which form solu duced by distilling a complex hydrocarbon frac tions in water, the separated aqueous solution ' tion in the presence of such compound and water may also be subjected to distillation to drive of! _ is first dehydrated, subsequent distillation under the'water contained in the solution. controlled conditions of the dehydrated azeo The dehydrated azeotropic distillate consisting ` tropic distillate results in the distillation of the 25 of the non-aromatic hydrocarbons and the azeo azeotrope former without removing overhead any` ‘ trope former is next subjected to fractionation in of the> hydrocarbons in the same manner -as order to separate the hydrocarbon from the azeo when the distillation of the initial 'hydrocarbon trope former. Fractionation may be accom fraction is’effected in the presence of the’azeo plished either at atmospheric, superatmospheric trope former. and in absence of water. / or under a vacuum but is preferably carried un ‘_Dehydration-of the azeotropicA distillate is 'ac der subatmospheric conditions since these condi tions result in effectively removing as an over head product substantially all of the azeotrope former as a fraction substantially free> from hy-- complished by merely contacting the azeotropic distillate with a dehydrating agent which has a preferential4 affinity for Water. Preferably this is accomplished by passing the azeotropic distillate through a bed of solid absorbent material which . . is adapted to absorb the water in preference to the 'organic materials contained in the azeotropic distillate. Solid materials adapted to absorb the 40 water‘from the azeotropic distillate include acti-î -vated clays, activated carbons, Activated Alu mina, activated silica, cotton, _also unactivated clays, carbons, aluminum, silica, etc. j drocarbons. The overhead, azeotrope formerfif relatively free from hydrocarbons may be mixed- with the proper quantity of water and returned to the azeotropic distillation step. In the event the thus separated azeotrope former contains a substantial portion of the hydrocarbons, this mix ture may be' condensed and then subjected to ex traction with a selective solvent adapted to dis „ solve one of the components, either the azeotrope Another method which lmay be employed for 45 former or. the hydrocarbons but not substantial quantities of the other component as will be de tillate includes -theuse of solid water soluble com scribed hereinafter. pounds such` as sodium chloride, calcium oxide - Other objects, features and advantages of my ' and chloride, sodium and .potassium carbonates; invention will be apparent to those skilled in the s sulfates and hydroxides and metallic salts of 50 art from the following description of the inven pyrosulfuric and pyrophosphoric acids such as the tion as taken from the accompanying drawings. pyrosulfates and pyrophosphates of potassium, In the drawings, Figure 1 represents a diagram sodium, zinc,- calcium, mercury, silver, copper, matic arrangement of apparatus for carrying out etc.-« When using these dehydrating agents, the my invention and Figure 2 represents a simplified solid as it absorbsthe moisture lfrom the azeo 55 flow diagram showing the important process steps» » separating the watel` from the azeotropic dis tropic distillate'forms a solution of the dehydrat-` " of the ' ing `agent and water 'which during the process of passing the azeotropic distillate through the solid compounds, separates -from the remaining invention. . . ' - ' In the following example, the invention will be described as applied to the separation of toluene , from ahydrocarbon fraction employing methyl i» solid compound and thus may lbe removed as a, 60 ethyl ketone containing about 10% by volume of bottom layer from the drier. water as the azeotrope former and clay as the` Also,- normally liquid materialsïmay be em dehydrating agent. Y ployed as dehydrating agents for separating the However, it will be observed ' that this example is not to be tal-:en as limiting water from the azeotropic distillate. Liquids my invention since the process is applicable to which may be employed for this purpose include 65 separate other components from complex sub glycerine, polyglycols such as mono-, di-, tri ethylene and other glycols, sulfuric acid, etc. De stances employing other azeotrope farmers con taining water under conditions adapted to eil‘ect the desired separation and other dehydrating hydration with these materials may be accom plished by simply .contacting the azeotropic dis Á tillat» or bubbling the vaporized azeotropic dis K tillate through a layer of the dehydrating liquid. Dehydration of the azeotropic distillate may also be accomplished by chilling the distillate to a temperature sulliciently lov.r to crystallize the agents. 70 ' « _ " ‘ In Figure 1, the hydrocarbon feed to be re solved into its _component parts preferably one having a narrow boiling range, not more than 50° F., such as for example', a hydrocarbon fraction having a boiling range of about 200 to 240° F. aqueous portion of the distillate which may then 75 and consisting of substantially 45% by volume 2,411,437 6 of toluene, 6% by volume of oleñns and the re mainder parailln and naphthene hydrocarbons when allowed to settle into an upper phase _com prising the b_ulk or the azeotropic distillate and consisting of substantially all ci the hydrocar bons and most‘ of the methyl ethyl ketone with obtained by fractionation of a catalytically re formed gasoline, is taken from tank I0 via line II and is pumped by pump I2 through line I4 fil some water and a lower phase consisting of sub- _ controlled by valve I5 into line I6. Azeotrope stantially all of the water containing the re former, such as methyl ethyl ketone, containing mainder of methyl ethyl ketone. In such case. it is preferable to pass the cooled azeotropic con about 10% water,` is takenfrom tank I1 via line I8 controlled by valve I9 and is pumped by pump densate from condenser 28 through lines 29 and 20 through lines 2l and 22 and valve 23 into line 10 3| controlled by valve 3Ia into a separator 32 IB where it is mixed with the hydrocarbon feed where the mixture is allowed to stratlfy into the two layers. The lower layer is withdrawn via from tank I0. The mixture of hydrocarbon feed and azeotrope former in the ratio of approxi line 34 and may be passed by pump 32a via line 33 controlled byvalveßäa to .a recovery system mately two parts of the azeotrope former and one part of hydrocarbon feed in the example for the recovery of the methyl ethyl ketone, as herein given, is passed into fractionating column will- be describedihereinafter. Preferably, it is passed into line 22 where it may' be mixed with 2d where the mixture is subjected to fractiona methyl ethyl ketone introduced into line 22 as tion, heat being supplied by closed steam coil 25. If desired, the azeotrope former may be in will be described hereinafter in such proportions troduced directly into the fractionating column 20 as to 'produce an azeotropeiormer containing an optimum amount of water which mixture may at any other point as near the top of the column then be recycled to the azeotropic distillate. The in which case it will act in part as reflux for upper layer is withdrawn via line 35 and passed the fractionation or reñux may lœ obtained by via line 30 to the methyl ethyl ketone recovery cooling coil 25a. In the fractionating column, the distillation is’controlled so as to distill over ` head an azeotrope consisting of the paraffin, ole system. i The bottoms in the fractionating column 2d ñn and naphthene hydrocarbons together with substantially all of the methyl ethyl ketone andv water. In the example herein given, this is ac# consisting of the aromatic fraction or toluene are compound such as its Iboiling point. The type of distillation to be used depends somewhat upon the quantity of the azeotrope event it is desired to recover the aromatic hy withdrawn via line 38 controlled by valve 3l and are pumped by pump 38 through line 39. If the complished at an overhead temperature of ap 30 hydrocarbon feed to the azeotropic distillation has been carefully fractionated to produce a frac proximately i60-170° F. and at atmospheric pres tion free from aromatic hydrocarbons other than sure. If desired, the azeotropic distillation may toluene and if the azeotropic distillation has been ' be carried out either at atmospheric or super atmospheric pressure or under a vacuum. Other i carried out under such conditions as to remove all of the non-aromatic hydrocarbons and azeotrope formers containing water which are azeotrope former, the bottoms from the frac- ' effective for separating the relatively non-aro tionating column may be passed directly via lines matic hydrocarbons from the relatively aromatic hydrocarbons include alcohols such as ethyl, nor 36, 39,740 controlled by valve 4I, lines 52, 43 con trolled by valve 44 and line »l5 into storage tank mal and isopropyl, primary, secondary and ter tiary butyl alcohols, other ketones such as diethyl 40 46. However, in the event the charging stock has not been carefully fractionated to remove ketone and methyl isobutyl ketone, dioxane, etc. The optimum amount of water to' be employed aromatic hydrocarbons heavier than toluene, with these azeotrope Íormers for eillcient opera such as xylene, etc., the bottoms in the fraction ating column 24 will contain all or substantial tion will vary from 5 to 25% by volume, depend ing. upon the characteristics of the particular ,5. m. amounts of such aromatic hydrocarbons. In the drocarbon mixture per se, it is passed directly to tank 46 as described above. However, if it is de sìred to separate the toluene from the :remain former used. I` may distill over any proportion of the petroleum fraction to be subjected to azeo 50 ing aromatic hydrocarbons, the bottoms are tropic distillation that I desire by adjusting the passed via lines 36, 39, 40. 42 into line 41 con quantity of azeotrope former. Thus. by employ trolled by valve 48 from which it passes through ing a relatively small proportion of the azeotrope heater 49 and line 50 into fractlonating column former, it is possible to distill overhead a portion 6I where the mixture is fractionated to remove of 'the relatively non-aromatic hydrocarbons and 55 the toluene as an overhead product aided by heat leave a portion as bottoms with the relatively from the heater 52. The vaporized toluene is re aromatic hydrocarbons, or by employing a rela ` moved from the top of the Iractlonatlng column tively larger amount of the azeotrope former, it El via line 53, condensed in condenser 54 and is possible to distill all of the relatively non-aro passed via line 65 into collecting tank 56. The matic hydrocarbons and a portion'of the rela 60 condensate may be withdrawn from the oollect- ‘ tively aromatic hydrocarbons, leaving relatively ing tank by pump 51 and passed into line 58. If aromatic hydrocarbons as still bottoms. desired, part of the condensate may be cycled via The above overhead mixture is removed'frorn line 59 controlled by valve 80 to the fractionat the iractionating column via line 26, controlled lng column "5I to serve as redux for the fractiona by valve 21, condensed in condenser 28 and passed 05 tion. The remaining portionis passed via >line via line 29 into line 3b controlled by valve 30a to Si controlled by valve 62 through line 46 into the methyl ethyl ketone-water 'recovery system, storage tank 46. The bottoms from the frac as will be described hereinafter. In some cases, tionating column, consisting of xylene or a mix depending upon the hydrocarbon iîeed and the ture of xylene and higher boiling aromatic 'hy character and composition of4 the azeotrope 70 drocarbons, is withdrawnvia line 63 controlled by former, the azeotropic distillate obtained in line valve Stand pumped by pump 65 and line B6V 26 will separate into two‘phases when properly into storage tank B1. cooled. In the case ofithe example herein de« In4 the event the bottoms fraction from the scribed, cooling of the azeotropic distillate to fractionating column 25 .contains a portion of about 50,-70° F., the condensate will-separate 75 the azeotropeiormer, this may be removed by 2,411,491 passing the bottom fractionv via lines 36, 39 and 68 controlled by valve 69 through heater 10 and line 1| into fractionating column 12 provided ' a temperature of 75° F. and under an absolute pressure of 100 millimeters- of mercury. The methyl ethyl ketone vapors may be passed via valve |00 into line -22 where it is mixed with the optimum amount of water such as obtained inline 34 and the mixture is passed via line I6 to `with a heater `13 and reflux cooling coil 14 where theazeotrope former may be fractionated and -removed via line 15, condensed in condenser 16 and passed via line 11 into collecting tank 18 from the azeotropic distillation in fractionating co1 which _it may b'e returned to the fractionating - umn 24. When the overhead from the fraction column 24 by pump 19 and line 80 Ycontrolled _ating column |00 contains non-aromatic hydro Aby valve 9| and lines 22 and IB. The bottoms lo carbons and it is desired to separate them, the from the fractionating column 12 may be passed overhead may be passed via line i0| _controlled via line 82 controlled by valve 83 into line 42 by valve |02, condensed in condenser |03 and from which it may be -‘passed by pump 84 either passed via line |04 into the bottom of an ex directly to the storage tank 46 or to fractionat tractor |05 which is provided with packing ma ing column 5| in accordance with the’above dis terial, such as broken tile |06, where the mix closure. ture is ‘countercurrently contacted with a selec The toluene or the mixture of toluene and tive solvent adapted to extract the methyl ethyl higher boiling aromatic hydrocarbons obtained ketone from the mixture. 'I‘he selective solvent in tank 46 and the higher boiling aromatic hy is obtained from tank |01 and passed via line drocarbons obtained in tank 61 may be treated 20 |08 controlled by valve |09 and ypumped by pumpi » with clay which may be accomplished at a tem H0 into the extractor |05. As selective solvents perature of about 230° F. employing l to 5 pounds adapted for the purpose, tetra ethylene glycol is of vclay per barrel of the hydrocarbon fraction. particularly suitable when used in about two If ldesired, the clay treatment may precede the volumes to one of the. hydrocarbon-methyl ethyl fractionation in fractionating column 5| in which ketone mixture at about atmospheric tempera- l _ case the 'fractionation in 5| may serve either to ture. rerun the clay treated stock and/or to fractionate Besides tetra-ethylene glycol mentionedabove, the high boiling aromatic hydrocarbons from the toluene". In place of clay treatment, the aro selective solvents which I have found suitable ' to effect the extraction of azeotrope formers from v matic fraction may be cooled and then treated ; azeotropic distillates include phenolic compounds such as resorcinol, para-chlorophenol, phenol, with 1 to 10 pounds of sulfuric acid per barrel of the hydrocarbons followed by neutralization with xylenol, pyrogallol, pyrocatechol and cresylic acid, clay or caustic alkali. The acid treatment serves to remove small traces of undesirable unsaturated v polyhydric alcohols such as di-, tri-. tetra- and hydrocarbons which may be detrimental in color stability'and nitration of the toluene. In order to recover the azeotrope former from the azeotropic distillate, the latter is passed into the bottom oi' either of the driers 85 through linesY 86 and valves 81 which are ypacked with a'clay 40 adapted to remove the water contained inthe dis tillate when passed upwardly in contact with the clay. If desired, the dehydration may be effected while the distillate is in the vapor phase and in hexaethylene glycols and dipropylene glycol,` amines such as mono-, di- and tri-ethanolamine, 2-methyl propanol amine, diethylene triamine, trlethylene te‘tramine, tetra-ethylene pentamine. diethylene diamine, tri-ethylene triamine, di phenylamine, xylidine, aniline, ,ortho phenylene diamine, alpha naphthol amine and phenyl hy drazine, fatty acids such as acetic, propionic and form'ic acids. aliphatic alcohols such as methyl. ethyl, isopropyl. tertiary butyl and normal propyl alcohols, ketones such as methyl ethyl ketone this respect„the >condenser 28 may be deleted or .i and acetone, cyclic lketones such as cyclohexan- " operated as a temperature regulator to adjust one, alkyl ethers of polyglycols such as mono the temperature of the distillate vaporto the ethyl ether of diethylene glycol and ethyl ether A proper level for optimum operation in the drier. Preferably,l ‘the drying is vaccomplished by per colating upwardly a condensate of the azeotropic distillate through the clay. The dehydrated azeotropic distillate is withdrawn from the driers 85 through valves l88~and I» line 89. Preferably the driers are operated alter- l nately, one being employed until 'the dehydrat ing agent is saturated with water so that it is no . llonger eifective to dehydrate the distillate, after _ of ethylene glycol, heterocyclic compounds s‘uch , as furfuryl alcohols. tetrahydro furfuryl alcohol. dioxane. morpholine, plperidine and thiophene, ' nitroparaflins such as nltromethane, nitroethane and nitropropane. In addition to the above. aro matic hydrocarbon solvents may be employed to ` effect the desired separation since the azeotrope formers have a‘ greater ailìnity for these hydro-` carbons than they have for the relatively non aromatic hydrocarbons contained in the azeo «which the distillate stream is diverted to the tropic distillate. Aromatic` hydrocarbon solvents other drier and the saturated dehydrating agent ’ - useful forA the purpose include benzene. toluene, is regenerated.¿ Regeneration is accomplished 60 xylenes, étc. ' Of the above selective solvents.- I = by blowing a heated gas. such as steam, air or have found the polyhydric alcohols such as di-. inert-gas through the dehydrating agent which tri- and tetra ethylene glycolsA amines such may be introduced via lines 90 controlled by as mono- and tri-ethanolamine and dii-ethylene valves 9|. The regenerating gases `and water sep triamine, and also'resorclnol and nitromethane arated from the dehydrating agent _in the ti'orm to be particularly eiiicient for extracting such of steam is removed from the driers 85 via‘lines azeotrope‘formers as methyl-ethyl ketone and 82 controlled by valves 93. methanol from azeotropic distillates containing The‘dehydrated distillate passing through line non-aromatic hydrocarbons having a boiling 80 is heated in heater 94 and passed via line 95 range of 2,00 to 240° F. , ' into the Vfractionating- column 96 which is pro 70 Instead of employing a selective solvent for the vided with heater 91 and reflux -coolingV coil 98 azeotrope former in order to separate it from the ' where the methyl ethyl ketone isvdistilled from hydrocarbons,- I may employ a solvent which is thehun-aromatic hydrocarbons and withdrawn from the fractionating column via line 98.. Frac u selective for the hydrocarbons and thus separate a solution of the solvent and hydrocarbons from tionation in“column 90 is preferably carried at 75 the azeotrope former. Solventsv adapted to ac 2,411,437 ll0 complish this purpose include highly parailinic chemically similar hydrocarbon components~ dis hydrocarbons of high boiling point such as solvent reñned lubricating oill fractions which have a -tilled therefrom which comprises distìlling said complex hydrocarbon fraction in the presence of greater affinity for the non-aromatic hydrocar bons than for azeotrope former. Also, low melt ing paraflin waxes and other paraiiin hydrocar a. suiiicient amount of an azeotrope` former and water to produce an azeotropic distillate consist ing of at least one class of the chemically similar components contained in said complex hydrocar bons may be used for this purpose. The non-aromatic hydrocarbons, if relatively , free of methyl ethyl ketone are withdrawn from bon fraction together with said azeotrope former and Water, thereby leaving at least one class of chemically similar components diiîerent from said chemically similar components contained in said azeotropic distillate -contained in said complex' hydrocarbon fraction in the residue, the steps of dehydrating said azeotropic distillate with a de hydrating agent, that bodily removes water sepa rating the remaining-azeotropic distillate from the dehydrating agent and water and fraction the top of the extractor |05 via line l|-| controlled by valve H2 and are pumped by pump H4 into storage tank H5, Non-aromatic hydrocarbons separated in fractionating column 96 are with drawn as bottoms via line H6 controlled by valve lli and are passed by pump | I8 into storage tank I l5. The solution of selective solvent and methyl ethyl ketone is withdrawn vla line l |9 controlled ally distilling said dehydrated azeotropic distillate by valve §20 and pumped by pump |2| through to separate the azeotrope former from hydro heater |22 into fractionating column |23 provided with heater |26 Where the mixture is fractionated 20 carbone. to separate the methyl ethyl ketone as an over head vapor which may be passed via line |25 and valve |26 through lines 2|, 22 and l5 into the fractionating column 2li or the overhead may be passed via line I2? controlled by valve |23, con densed in condenser iig and collected in collect 2. In a process for the treatment .of a complex hydrocarbon fraction to separate chemically sim ilar hydrocarbon components therefrom from other hydrocarbon components contained there in which ordinarily distill from the hydrocarbon fraction in the same temperature range as said ing tank |36. As indicated above, the lower layer in separator 32 passing through line 33 may also be passed into the fractionatlng column |23 for, chemically similar hydrocarbon components dis tilled therefrom which comprises distilling said may be passed via line E32 controlled by valve components contained in said complex hydro carbon fraction together with said :azeotrope complex hydrocarbon fraction in the presence of the recovery of the azeotrope former. The con 30 a suñcient amount of an azeotrope former and water to produce an azeotropic distillate consist densate is Withdrawn from the bottom of the ing of at least one class of the chemically similar4 collecting tank by pump |3| and ‘part thereof |33 to fractionating column `|23 to serve as reñ‘ux for the fractionation. The remaining portion of the condensate is passed via line ist controlled by valve §35 into storage tank il. The selective solvent is withdrawn from the bottom of the fractionating column |23 via line |36 controlled by valve I3? and is pumped by pump §38 through cooler i3d and line iëlû to storage tank lill. As disclosed above, the methyl ethyl ketone dis tilled as an overhead vapor in fractionating col umns 96 and |23 may be passed to the azeotropic distillation in iractionating column 2d to serve as azeotrope former for the distillation. How ever, since the azeotropic distillation in 24 is pref erably carried out in the presence of a mixture' of 90% methyl ethyl ketone and 10% water, the overhead >vapor from fractionatlng columns 96 and £23 will be relatively free of water and thus this overhead vapor must be adjusted to the . former and water, thereby leaving at least one class of chemically similar components different from said chemically similar components con tained in said azeotropic distillate contained in said complex hydrocarbon fraction in the residue, the steps of dehydrating said azeotropic distil late with a dehydrating agent, that bodily7 removes water separating the remaining azeotropic distil late from the dehydrating agent and water and fractionally distilling said dehydrated azeotropic ' distillate at a reduced pressure to separate the azeotrope former from hydrocarbons. 3. In a process for the treatment of a complex hydrocarbon fraction to separate it into com ponent' parts of dissimilar characteristics which, comprises .distilling said complex hydrocarbon fraction in the presence of a sumcient amount of an aqueous azeotrope former to produce an azeo tropicvdistillate consisting of at least one of the components contained in said complex hydrocar tropic distillate from 24 is cooled and separated 55 bon fraction together with said azeotrope former and Water, thereby leaving at least one of the in separator 32 and the bottom layer consists sub components contained in said complex hydrocar stantially of' Water, this bottom layer may be bon fraction in the residue, the steps of dehydrat mixed with the overhead from fractionating col ing said azeotropic distillate with a dehydrating umn 9S and |23 to effect, in part, the desired ad agent, that bodily removes water separating the justment of water, content in the azeotrope dehydrated azeotropic distillate from the dehy former. Also; the water separated from driers @E may be passed into line 22 to effect the above , dra-ting agent and water, fractionally distilling said dehydrated azeotropic distillate to 4separate 'adjustment of water content. the azeotrope former together with a portion of The foregoing description of my invention ls not to be taken as limiting my invention but only 65 hydrocarbons contained in said azeotropic distil late from remaining hydrocarbons and extracting as illustrative thereof since many variations may said separated mixture with a selective solvent be made by those skilled in the art without de to separate said azeotrope former from said hy parting from the scope of the following claims, dro'carbons. I claim: . 4. Ina process for the treatment of a complex 1, In a process for the treatment of _a complex hydro-carbon fraction to separate chemically sim hydrocarbon fraction to separate chemically sim ilar hydrocarbon components therefrom from ilar hydrocarbon components therefrom from other hydrocarbon components contained there > other hydrocarbon components contained there proper water content by addition of water. In A = some casesas described above, when the azeo in which ordinarily distill from the hydrccarbonV in Ywhich ordinarily distill from the hydrocarbon .~ fraction in the same temperature range as said 75 fraction in the same temperature range as said Il 2,41 1,487 _ chemically similar hydrocarbon components dls- v till therefrom, which comprises distilling said lar components contained in said complex hydro carbon fraction together withl said azeotrope former and water, thereby leaving at least one components contained in said complex hydrocar bon fraction together with said azeotrope former and water, thereby leaving at least one class oi class of chemically similar components, diiIer ent from said chemically similar components contained in said azeotropic distillate, contained in said complex hydrocarbon fraction, in the resi due, the steps oi' dehydrating said azeotropic dis chemically similar components, diiïerent from „'said chemically 'similar components contained in ' said azeotropic distillate, contained in said com plex hydrocarbon fraction, in the residue, the steps oi dehydrating said azeotropic distillate with tillate withl a solid absorbent- that bodily removes Water separating the dehydrated azeotropic dis a solid absorbent that bodily removes water, sepa-. tillate from the solid absorbent and water and rating the remaining azeotropic distillate from fractionally distilling said dehydrated azeotropic the solid absorbent and water and separating the distillate to separate the azeotrope former from y azeotrope former from hydrocarbons. 5. In a process for the treatment of a complex l hydrocarbon fraction to separate chemically sim ilar hydrocarbon components therefrom from 20 chemically similar hydrocarbon components dis till therefrom, which comprises distilling said ‘ water to produce an azeotropic distillate consist ing of at least one- class of the chemically simi a suiiicient amount of an azeotrope former and water to produce an azeotropic distillate consist ing of at least one class of the chemically similar fraction in the same temperature range as said 12 a suiflcient amount of an azeotrope former and ' complex hydrocarbon fraction in the presence of otherl hydrocarbon components contained therein which ordinarily disti11 from the hydrocarbon l complex hydrocarbon fraction in the presence of hydrocarbons. 6. A process according to claim 4 in which said solid absorbent is clay. 7. A process according to claim 4 in which said solid absorbent is carbon. - 8. A process according to claim 4 in which said solid absorbent is alumina. « ‘ _ GEORGE R. LAKE.