Патент USA US2370810код для вставки
March 6, c. E ,MORRELL E‘rAl. 2,370,810 PÈOCESS 4FOR SEGREGATING ‘VALUABLE HYDROCARBON CONSTITUÈNTS Filed Aug. 21, 1942 ‘2,310,816 l , :Patented Mar# 6,11945 A ` .UNITED "s'rATlszs> PATENT _OFFICE i " . \ 2,310,810» ' ` r'nocnss ron sEGnEGA'r'ING vALUABLa i mmaocmaon coNsTrrUnNTs Charles Morrell, Roselle, and Miller W. Swaney, Linden, N. J., assignors to Standard 0i! Development Company, a corporation ¿of f Delaware P Application ' ' 1oAugust claims.21,l(ci. 1942, 26o-677) serial No..455,s7c The `presentinvention relates to the art ofthe segregation of certain unsaturated hydrocarbons from mixtures with other hydrocarbons of closely similar boiling points, and more speciilcally to the ' the above mentioned process by which increased yieldsmay be obtained. ~ - ` Referring to the drawing, numeral E_denotes. a line through which the hydrocarbon feed is in troduced. For purposes of illustration, a refinery .Ca cut from cracking' operations will be taken separation and purification of tertiary oleflns from their mixtures `withvnorinal or- secondary y oleñns or from saturated hydrocarbons. ' but it will be understood that a Cs cut or other mixture of hydrocarbons including tertiary oleñns The process will be understood from the fol lowing description and drawing. The drawing- is might be taken equally well for purposes of illus asemi-diagrammatic view in- sectional elevation 10 tration. ‘ The cut‘ is preferably a rather narrow showing the ilow of the various materials em boiling fraction, such as can be readily producedA ployed in the process. * ' ' in ordinary reiinery equipment without great Tertiary oleñns, such as isobutylene and iso-. .difñculty. The feed stock is preferably fed in amylenefoccur together with many’ other oleflns, liquid phase and sufficient pressure is imposed to maintain it throughout the absorption step. ,both normal and secondary, as well as saturated hydrocarbons.' in cracked 'hydrocarbon oil frac;v , In addition to the feed stock, a second" liquid hydro-carbon of a higher boiling point than _the . tions, and it-has been for some time desirable to develop- a’chïeap, effective method for segregating ~ original feed s'tcck, but boiling below the boiling* point of the phenolic material used, is also sup-` the tertiary oleilns from other constituents in‘ narrow boiling cuts. In the lower molecular 20 plied by the pipe 2. The nature of this hydrof. weight ranges, forexample,- in'the so-called C; carbon,-which is termed the “added hydrocarbon” l 5 will be more speciilcally disclosed later. A suit and Cs cuts, which comprise those hydrocarbons having 4 and 5 carbon atoms respectively inthe molecule, separation can be accomplished by dis tillation but ‘due to the close boiling points, this is a very diilicult and expensive operation. Bet ’ ter results have been obtained by chemical means; for example», isobutylene has been selec tively extracted from normal butenes and butanes by solution in 65% to 75% sulfuric acid.' Acids of this strength absorb the tertiary olefin without substantially> añecting the normal olefins or _ parafllns, and the iso-olefin can be recovered from the acid liquor by dilution Iand distillation. ' Another methodî of accomplishing the same re sult employsfa mixture of phenols, cresols and able, absorption medium, which for the present will be described as a, phenolic material, is added through a pipe 3 and the mixture of thesè three materials is passed through an absorption zone t by way of a common leader pipe da. An alkylat ing catalyst supplied by pipe 4b isfsmall in amount. ' and it is preferably also added to the leader. 30 This mixture of ingredients now passes' through `the absorption zone 4 in liquid phase. Any par ticula'i- desigm for the absorption zone may be employed in which all of _the ingredients are mixed thoroughly and given soient time for er" reaction. As shown in the drawing, the reaction the like along with" a minor amount of- mineral zone is' merely a pipe ñtted with bañies-b and a jacket 6a through which a coolingmedium may alkylation acid by 'means _of which the reactive tertiary oleflns are caused to unite with“ the phenolic material to .form an alkylated phenol. >~be circulated, since there is considerable heat evolved in the alkylation step. The conditions . The unailectedhydrocarbons may be distilled oilI to alkylate .the phenolic material, the other oleñns from this product and the residue, which' consists of the alkylated phenol, is then heated to effect the dealkyl'ation so that the .tertiary oleñn is'then ' are such that only the tertiary olefins are caused passing' through substantially unaüected. The reaction product is discharged through a heating coil Gf and into a distillation column l which is» collected and the phenol returned. ' This method is not -entirely satisfactory be- ' cause of the fact that the yield is not as high as- coil> 8 at its lower end; In this fractionating zone, -the ~'uncombined hydrocarbons, namely the might vbe desired due- to Several factors; ilrst, - butanes and the normal butenes, are distilledy ` ' polymerization oi’ the tertiary oleiin: second, the >provided with a reñuxing coil 8 and a reboiling` overhead through a pipe l0, condensed in acon- - fact that some tertiaryoleiln's are. distilled over 50 denser l2 and collected inthe drum I3 through which they may be withdrawn as a liquid, _by pipe along with the unalkylated tractionsfof the feed stock and, infra, because of the amenity-'m- com pletely removing the absorbed tertiary olefin from the phenolic material inthe recovery step. The present invention involves an ‘improvement over I _4, From the base oi' the tower 1,. the residue con taining the alkylated phenolic material and the added hydrocarbon along with a small amount of" .alkylation catalyst passes by pipe» IB through a - 2 “ j andere material without causing any substantial poly heat exchanger II and a second heating coil l1 y "and thence into aA stripping tower In Thistower merization of the tertiary oledn. , An important feature'of the process is the pres- . is similar to tower 'I containing the reñuxing coil ence of the so-called added hydrocarbon which, i0 and reboiling coil 2l. It will be understood that vin this >tower, the temperature is raised to 5 _ asstated above, should be a relatively stable ma- -' ' alkylated phenol and the distillation overhead not only of the tertiary olenns but also of the added terial boiling conveniently above >the boiling . range of the feed stock and ., below the 4phenolic material so that it may be on the one hand readily hydrocarbon. The vaporized substances removed separated Vfrom the unabsorbed constituents of> a sufficient point to cause the _dealkylation of the by a pipe 2| and discharged into a secondary lo’the feed stock by the first distillation step and from the regenerated tertiary olefin and likewise tower 22 which is similar to thoseshown above readily separated from the phenolic material in and is devised to make a close fractionation be tween the tertiary olefin and the higher boiling ‘ added hydrocarbon. The tertiary oleñn is taken overhead by a pipe 23, is condensed in 24 and 15 the regeneration step. When isobutylene is re covered from Ct cuts, pentane is an admirable material to employ but other materials may be used as well, for example hexane, di-isobutylene and other equivalent materials.A The added hy drocarbon is preferably added at the inlet' of the collected in 25. It is withdrawn as a liquid by a pipe 28. The added hydrocarbon is withdrawn from the base of tower 22 >by a pipe 21 and is passed by a pump 28a for recirculation. It is~ ' 'absorber 4 so that it may be. present during the preferably joined by the'stripped phenolic mate~ 20 absorption. When so used it tends to slow down the alkylation reaction, making the control easier, rial from tower il which is added by pipe 20 and the mixture formed by the materials .ñowing a and tends to prevent excess polymerization of the C4 oleñns. It mayfhowever, be added to the re through pipes 21-and 28 then passes'through the` action mixture iust after the absorption is com heat exchanger il; through a cooler.” and by a pipe 30 back to the leader 4a and the absorber 5. 25 plete. The amount of the added hydrocarbon >can be varied over quite a range. say from 10 to 100%, by volume, based on the amount of phe- f A\’I'h\xs it will be seen that the phenolic material, the added hydrocarbon andthe alkylation -cata. - lyst are continually circulated through a, closed system and used over and over again to _treat nolic material, but from «i0 to 60% is generally ' quite satisfactory. fresh quantities of the C; cut which is,continually o After' the absorption _is complete, the first step is the distillation of the normal oleflns and the added and resolved into components consisting . saturated hydrocarbons contained in the feed on the one hand ofthe.- tertiary oleilns and on the other of a mixture of oleflns and saturated C4V ’ stock. -This distillation is `carried out preferably >under pressure so that the products may be col hydrocarbons. ' . e ¿In the operation of the present process, it will 35 lected in liquid phase without the use of refrig eration and with the C4 cut this distillation may be understood that the absorbent material is of a be accomplished under super-atmospheric pres phenolic nature. ,Phenol itself may be used for , sure. say 40 to 60 pounds gauge. The'head tem 'this purpose or a cresol, or a mixture of cresols perature `of the stillwill be about 43° C. and the with or without other phenols. An advantageous absorption medium consists of a mono-tertiary 40 bottom temperature about 82° C. .In any case, the bottom temperature of this first distillation phenol such as tert-butyl phenol -or tert-amyl should not be above about 100" C., ,in order to phenol. Simple phenol has been found capable prevent a partial dealkylation and loss of the of readily absorbing three molecules of iso butylene and of readily evolving two molecules tertiary olefin. 'I'he residue from the first dis- l . thereof so that in eifeet _even when operation is 45 tillation consists of the phenol-tertiary oleiln begun with simple phenol after a while`the ab- „ alkylate, the acid catalyst and the added hydro- „ sorption medium is largely mono-tert-butyi carbon and this mixture, which forms 'a single phenol‘which has proved to be a very satisfactory » phase, is passed into thesecond distillation col umn or 4the regenerator. Thisdistillation column modo o1’ operation. If dealkylation conditions maintained are'sumciently drastic, however. all to ls‘nkewise preferably held under pressure and terials Vduring absorption are maintained, as indie the temperature is raised sufficiently high'to not only cause the dealkylation of thephenol but also to distill olf not only the tertiary olefin but cated above, preferably in the liquid phase at likewise causethe distillation of the addedhy tert-butyl _groups can be remov and the mono butyl phenol converted back to henol. è' The ma .temperatures between about 60° and 100° C., and 55 drocarbon. The actual temperature therefore \ a complete absorption of the tert-oleiin. can’be. _depends on the boiling` point of the added hydrocarbon, the “extent of alkylation ofthe phenol accomplished in from 201:0 120 minutes, depend- V andbther conditions. `With pentane and using ins on the amount of tert-olefin in the feed.v stock, -the’ratio of absorption agent to the feed ' a` pressure of say 50 to "I0 pounds gauge, the l stock and other ponditions. It is found desirable' .o - to provide about ¿33 to 1.0 mois of phenolic mate ~rial for each mol of iso-oleñn to be absorbed al- ' l. though even‘ higher ratiornjxay be used. The , v alkylation d_ealkylation catalyst is .preferably a maximum temperature will be about 250° C. .4 - When working at lower pressures, below 50 pounds. lower temperatures. in therange of 150 to 200° Cfare adequate. In cases where the phenol is combined with 2 to 3 molecules of ole- l mineral acid, suchfas concentrated sulfuric or c5 iin in the absorption step. regeneration tempera .concentrated phosphoric acid,` but bther acid re' ' tures as low as 100 to.110' C.' sumce at pressuresA close to atmospheric._ The added _hydrocarbon rapidly sweeps the tertiary olefin out of the phe _ate or _ pho'sphatemay alsobe used,- as well _as benzene or ` :acting catalysts such as potassium acid- nolas soon as it is released and prevents loss amount of the alhlation'catalyst is small indeed. 70 on the one hand from incomplete dealkylation phenol-sulfonic acids or some of their salts. The , for example from 0.1 t6 `i0 mol per cent' thereof ` based _on -thejphenol or equivalent material em ployed, _and with otherwise` good conditions about _ one `mol'per> cent of’the _catalyst _is quite effective - and on the other‘from polymerization during the _ regeneration step. ~ ~ ' ‘ The third Fdistillation step is also preferably _ accomplishedunder pressure vso aste permit the « . _ in quickly effecting theaikylationof the'phenolic 7e tertiary olefin to be eollectedin liquid phase at 2,310,810 cooling water temperature. In this last still, the separation is made between the tertiary olefin and the added hydrocarbon and from the nature of the separation required, it will be readily un derstood that the added hydrocarbon should con veniently boil above the boiling point of the tert oleñn to be segregated. 'I‘he closer the added hydrocarbon boils to the tertiary olefin the more diillcult this separatio-n will be.` In any case, a mixture of the phenolic material removed from tower i8 and the added hydrocarbon taken from tower 22 are returned or recycled for furtherV reaction. As indicated before, the phenolic nia terial which also contains the alkylation catalyst _ « Q -olefin and a dealkylated phenolic material, while in thepresence of an added hydrocarbon having `a boiling point between that of the tertiary olefin and lthe phenolic material', andV also in the pres ence of an acidic dealkylation catalyst, whereby~ the tertiary oleiin and the added hydrocarbon are distilled. from the dealkylated material, and sep-v arating the tertiary olefin and the added hydro- _ carbon- by fractional distillation. f 3. Process »according to claim 2 in which the added hydrocarbon is employed in an amount. of 10 to 100% of the volume of the phenolic ab sorbent. ' ` 4. An improved process for recovering tertiary is returned to the inlet of the reactor 4. The" 15 oleflns from hydrocarbon> mixtures >of similar boil added yhydrocarbonis also preferably returned Íto ' ing range containing tertiary olef'lns which com prises admixing with the hydrocarbon feed a the same point but may be returned to the inlet phenolic material- and, a minor amount of an of the heating coil 6, if desired. alkylation'.catalyst,- whereby the tertiaryolefin As a specific example of the operation of the process, a mixture of meta and para cresols and 20 alkylates the said phenol, distilling ofi the un alkylated hydrocarbons contained, in the feed a C4 cut containing 18-l`9% isobutylene was con stock ata temperature below that at which de* tinuously fed into and through a steel reaction alkylation takes place, and while in the presence drum at 85 to 90° C. -Pressure sufficient to main «f tain the reactants in liquid vphase was provided ' of> an added hydrocarbon boiling between the and the reactor was of size to give a time of125 tertiary olefin and the phenolic material, lregen throughput of about 1 hour. The mixture i'ed - consisted of 5 mols cresol to 1 more ofisobutylene and about .2 mol per cent of cresol sulphonlc acid - based on the cresols was included in the feed. As the reaction mixture emerged from the chamber it was continuously admixed with onef half of its value of mixed -pentanes and this . mixture sent to a distillation towerwhich was under 3 atmospheres pressure (abs.) and distilla tionof the C4 hydrocarbon was effected using a 1' maximum temperature 'of 95 to 100° C. Practi cally no decomposition of the alkyl phenol was ‘ noted during this distillation. v The debutanized mixture was now distilled in a regeneration tower with a maximum tem perature of 200° C. and under atmospheric pres sure. From the top of the tower 'a mixture of pentane and regenerated isobutylene was recov» eratingpthe tertiary olefin by heating the tertiary alkylated phenol to a dealkylating temperature and distilling the tertiary olefin and the'added hydrocarbon from the regeneratedphenolic ma teria-l, then separating theregenerated tertiary oleñn from the added hydrocarbon by fractional distillation and returning the phenol and the hy drocarbon for reuse. ' 5. Process according to claim: 4 in 'which theadded hydrocarbon is >a saturated hydrocarbon and it is present during, the alkylation step. ~ 6. _Process according to claim 4 in which the - added-hydrocarbon is asaturated hydrocarbon and it‘is added to the alkylation product. 7. An improved process for recovering isobutyl- - ene from its mixtures with other C4 hydrocarbons which comprises agitating the C4 hydrocarbons in the liquid phase with- a phenolic absorbent and a small amount of an alkylation catalyst While in ered while the regenerated cresol and catalyst were drawnvoff of the tower from the bottom and ß. the presence of an addedhydrocarbon having a boiling point between that of the C4 hydrocar reused for further absorption of isobutene. .The bons and the phenolic absorbent, whereby the iso regenerated isobutene and the pentanes were / butylene is chemically combined with the phenolic separated'by distillation and the pentane reused as before. A careful balance showed that 93.7%`-v y absorbent 4to'i’orm an alkylated phenolic product, ' distilling the uncombined C4 hydrocarbons origg of the isobutene fed tothe system was recovered . inally >in the feed at atemperature below that at ' and the product contained 97.2% isobutene. which dealliylation-tak'es place, heating the al The present invention is not to be limited to kvlated phenolic product while still -in the pres the 'segregation of any particular tertiary olefinA en-ce of the added hydrocarbon and the alkylation nor to the use of any particular phenolic mate catalyst to a temperature between about- 100° and rial nor to any particular alkylation catalyst or 250° C., whereby _the phenolic substance is de -added hydrocarbon, but only to the following alkylated, removing. the regenerated tertiary claims in which it isdesiredto claim ali novelty butylene and the added hydrocarbonas vapors 'inherent in the invention. from the phenolic absorbent and separatingv the ‘ We claim: isobutylene' from the added hydrocarbon by frac 1.- An improved process for recovering tertiary tional distillation, `collectlng` the isobutylene and olefin from tertiary alkylated phenolic material, which comprises heating >the alkylated material in order to produce thetertiary olefin and produce'a Adealkylatecl material in the presence of an added hydrocarbon having a boiling temperature be, tween thatA of the olefin recovered and the dealkyl .ated phenolic material, whereby the tertiary olefin and the added hydrocarbon are distilled from the dealkylated phenolic materiahand thereafter sep» .. arating the tertiary oleñn andthe added hydro'-._ carbon by fractional distillation. > _2. An improved process for recovering tertiary olefins from an alkylated phenolic material, which comprises heating 'the alkylated material to a dealkylating temperature to produces. tertiary recirculating the said added hydrocarbon along with the phenolic absorbent to the process. 8„Process according to claim 7A in which the , phenolic solvent is mono-tertiary butyl phenol. 9.» An improved lprocess for recovering tertiary amylenesv from their mixtures with other C5 hy drocarbons which comprises'agitating the Ca hy drocarbons in the liquid phasewith a phenolic absorbent,v and a°small amount of an alkylation catalyst while in the presence of an added hy drocarbcn' having a boiling point between that of the C5 hydrocarbcnt and the phenolic absorbent. .whereby the tertiary olefins arevchemically com bined with the' phenolic absorbent to form an 4 _ _ asma-10 alkylation prodiict, distllllng the uncombined Cs hydrocarbon a's‘vapors from the~~ phenolic absorb- ent and separating the tertiary amylenes from ture below that at which dealkylation takes place, the added hydrocarbon by fractional distillation. heating the alkylated phenolic absorbent while collecting the former and recirculating the latter _still in the presence of the added hydrocarbon and' 5 along with the phenolic absorbent to the process. the alkylation catalyst to a temperature between ' 10. Process according to claim 9 in which the . hydrocarbons originally in the feed at a tex?pera _ about _100° and 250° C., whereby the phenolic sub stance is dealkylated producing tertiary amylenes and a dealkylated phenolic absorbent, removing the regenerated tertiary amylenes and the added l0 phenolic absorbent is mono-tertiary amyl phenol. CHARLES E. MORRELL mma w. swarmï.