Патент USA US2403439код для вставки
2,403,439 Patented July 9, 1946 ' UNITED STATES PATENT orrlce > 2,403,439 ‘PROCESS FOR ISOMERIZING MONO OLEFINS ' Vladimir N. Ipatieff and George S. Monroe, River-v side‘, ‘111;, assignors to Universal Oil Products Company, Chicago, 11]., a corporation of Dela- I ware, ' No Drawing. Application August 19, 1943, ' Serial No. 499,252 8Claims. (c1. zoo-683.2) ' . sion of hydrocarbons and is more'particularly di rected to the shifting of the position of the double bond in an ole?nic hydrocarbon by cat alytic means. ' ‘ ‘H, . Y. - . would be practically impossible bylfractionation. However, itis also evidentthat if the butene-l can be converted to butene-2, the separation can _ In view of the recent developments in the pe troleum industry,‘ particularly in the manufac ture of aviation gasolines and synthetic rubber, methods for shifting the position of the double bond in ole?nic hydrocarbons have become in 2 It is apparent from the above table that the vseparation of the individual hydrocarbons, more particularly isobutene from normal butane-1, The present invention relates to the conver be accomplished with comparative ‘ease. ~ Various catalytic materials have been proposed forthe isomerization ofole?nssuch as silica gel, 10 alumina, bauxites, alruninum sulfate», concen creasingly important. It has, been found that alkymers produced by alkylation of normal bu trated solutions of zinc chloride, benzene sulfonic acid and so forth. However,;these catalysts also tene-2 possess more desirable antiknock proper tend to promote undesirable side reactions such ties than those produced by alkylation of the as polymerization to produce high boiling poly isomer normal butene-l. In the manufacture of 15 mers regardless of the operating conditions em synthetic rubber, the length of the chain in the high molecular weight polymers produced by polymerization of such compounds as isobutene with butadiene or styrene depends in a large measure on the purity of the reactants and con ployed in the reaction. . . -‘ It is an object of this invention to present a method for selectively utilizing the shifting of the double bond- within an ole?n hydrocarbon 20 Without substantial polymerization ‘of the ole?n to higher boiling hydrocarbons. trols to a certain extent the physical and chemi cal properties of the resultant rubber. It is, therefore, essential in the manufacture of these synthetic rubbers that the reactants be of a high degree of purity. Similarly, the catalytic dehy 25 drogenation of butenes into butadienelone of the principal reactants in rubber manufacture, is per It is another object of this invention to pro vide a method of shifting thGgDOSitlOl’l of the double bond of ole?nic hydrocarbons without changing the structural arrangement of the car bon atoms, in the hydrocarbon molecules. We have discovered a select group of catalysts formed more readily with-less carbon formation which may be employed over a wide range of and greater butadiene yields when the dehydro genation charge is substantially free from iso operating conditions to accomplish the objects 30 mentioned. In one broad aspect, the present invention con sists of a process for shifting the position of the double bond in an ole?nic hydrocarbon which butene. Thepresent invention provides a method of separating the C4 ‘hydrocarbons to produce products of sufficient purity that they may be satisfactorily employed in synthetic rubber man ufacture and in the production of butadiene. It is well known that a C4 hydrocarbon fraction cannot be separated into the individual C4 hy comprises subjecting said ole?nic hydrocarbon 35 to contact under ole?n isomerizing conditions with a catalyst comprising a dilute aqueous so lution of a strong non-oxidizing acid. We have found that the double bond, contained drocarbons by simple fractional distillation since the boiling points-of the varlous'hydrocarbons are somewhat similar. This is particularly true with a mixture of C4 ole?ns containing isobutene and normal butene-l, or a mixture containing these 40 in ole?n hydrocarbons such. as butene-l, pen~ tene-l, 2.3-‘dimethyl butene-l, andthe like can be shifted by the in?uence of catalyst materials comprising dilute aqueous solutions of strong non-oxidizing acids such as hydrogen chloride, hydrogen bromide or dilute acidic solutions of ole?ns and C4 para?ins. The following table gives the boiling points of the various C4 hydro 45 easily hydrolyzed' salts of such acids such .as am carbons at one atmosphere pressure. monium chloride, iron chloride. nickel chloride. manganese chloride, magnesium chlorideand the Boiling points at 1 atmvsphere'pressure corresponding bromides, and the like. i ‘ °C. The operation maybe conducted over wide Isobutane ___________ __; _______ __‘ _____ __ —11.8 Isobutene ____________________________ __ +6.6 Normal butane-1 ____________________ -fNormal butane _____________________ __»__r —6.4 —0.5 ranges of temperature and pressure depending primarily upon the hydrocarbon being isomerized and the catalyst employed. Generally speaking, temperatures within the range of about 25‘ to 400° 'C., preferably 150. to '300“ 0.’, and pressures of subatmospheric, atmospheric or substantially Normal butene-2 trans ____________ __'____ +1 Normal butene-z cis ____ -a ___________ __,_ +3.7 2,403,439 3 superatmospheric pressure may be satisfactorily higher once through yields of butene-2 in the products. employed. To maintain the selectivity of the The reaction may be conducted in a series of reaction, the catalyst concentration in the aque isomerization zones with intermediateseparation ous solution must be carefully controlled. The solution should be mildly acidic, preferably at a 5 ‘of the isomerized product to effect a substantially complete conversion of the olefin to the desired pH of about 3 or more. The exact pH of the catalyst solution is dependent upon the charge . isomer. and operating conditions used and is best deter-' ‘ The following examples are introduced as illus mined by small scale experimental tests. ' ' - 1 trative of: the :results obtainable in the practice Various methods of operating may be employed: "10 of the present process in the isomerization of For example, the vapors of the charging stool; butene-lto butene-Z and isomerization of 2,3 may be bubbled upwardly through‘ stationary = dimethyl butene-l to 2,3-dimethyl butene-2, but pools of dilute aqueous solutions of the catalyst } 7,, it is not intended that the scope of the invention ' should be limited-in exact accordance with the or by similarly passing the vapors upwardly coun tercurrent to the descending catalyst solution in data presented. 7 vertical reactors containing ?lling'or'spacing‘m'a terials such as, for example, granular fragments '- ' ' " of relatively inert materials such as silica, alu- ' ., .In run "No. 1 shown in Table I given below, mina, ?rebrick and'the like, or regularly spaced ' weighed amounts of normal butene-l, Water and pans and trays may beemployed to insure good 20 ammonium chloride were placed in a steel rotat contact between the charge and catalyst solu tions. ‘ ing autoclave containing a glass liner.v The reac tion was conducted under the conditions shown in Table I given below andv the products were re . Alternatively the reaction may be conducted by passing the, ole?ns either alone or in admix moved from the autoclave and analyzed.- - ture with other hydrocarbons in, substantially test in which similar quantities. of butene-Land water were charged to the rotating autoclave. catalyst solution through tubular elements un der conditions of turbulent flow, the products This run- was madeto determine whether the from’ the tubular elements being passed into sep water present in the autoclave had any isomer arating chambers from which the hydrocarbon izing activity. It is evident from .thedata pre~ products‘ are passed to a fractionator and the sep sented in Table I that the sole catalytic, e?ect was due to the presenceof the ammonium chlo arated catalyst solutions returned for further service. The separated catalyst solution may be adjusted to ‘the proper pH by the addition of fresh ride in the reaction vessel. acid or salts prior to recycling to the tubular 35 elements. > ' Run No. 2 shown in-Table I is a- comparative liquid‘phase and‘ a proportioned amount ' of a 7 > TABLE, I ' Still another method of conducting the reac~ tions consists of introducing the charge and cata— lyst solution into a rotating vessel or a vessel pro vided with some means of obtaining rapid mixing of the hydrocarbon and catalyst such as, for example, a Stratfor'd contactor‘ or turbo mixer, ‘ lsom‘erz'zatz'on of butene-I to buténc-Z with dilute aqueous ammonium chloride solution ' - passing the effluent from the vessel into a sep Charge: <-—- Normal butene-l -‘--> aration zone wherein hydrocarbons are separated from the’catalyst solution and recycling catalyst 45 Run No. 1 ;Run No. 2 solution containing the proper amount of ‘acid or salt to the reaction vessel. The hydrocarbon Time at operating temp, hours_ _ _ 3 " 3 products are then fractionaly distilled to separate Temp., ° O____r _______ __, _______ __ . 230 230 the converted from the unconverted hydrocarbons Pressure, atmospheres __________ __ 88-95 88-122 which later may be recycled to the reaction zone. 50 Charge: Weight per cent" 37. 3 36. 6 This invention is applicable not only to a single 61. 5 63. 4 ole?n hydrocarbon or mixtures of ole?nic hydro Operating conditions: carbons but also to mixtures of one or more ole ?ns with saturated hydrocarbons such as, for example, the fractions obtained from the cata-. 55 lytic and thermal cracking of heavier hydro carbon oils. It is particularly applicable to the 04 fractions of the aforesaid source and permits the conversion of‘ butene-l’to butene-2 in the pres ence of isobutene Without substantial conversion 60 of the isobutene to normal butenes or polymers. It is, of course, evident that if the invention is employed to separate C4 hydrocarbon fractions to recover isobutene without contamination by bu-, tene-l or to recover a maximum of butene-Z, the ‘as ' . > ‘ Since the isomerization reaction is an equi librium reaction, this preliminary separation will aid in the subsequent visomerization ‘operation. The butene-2 ordinarily present ‘ in v‘the charge would tend to decrease the rate of reaction; and its removalprior to the isomerization will ‘permit’ l . 7 _ 1. 2 ____________ __ Total _________________________ _. 100.0 100.0 Products, wt. per cent of butene-l charged: > Butene-2 ________________________ __ Butened, recovered _____________ .. C5+hydrocarbons _ _ _ _ _ _ Polymer ___________ __ 04 alcohols __________ _. _ _ . . _ . _ _ 44,2 37.6 l. 0 > ~ 1. 7 95. 2 0. 7 __ _. 0.0 0.0 ___ 5.3 0.0 Loss+uncondensable ga _ Total _________________________ __ 11.9 2. 4 100.0 100. 0 EXAMPLE II In Example‘II, results of which are shown in Table II given below, weighed amounts of 2,3-di methyl butene-l, water and ammonium chloride butene-Z originally present in the fraction should be removed by fractional distillation prior to the desired isomerization operation. , 76 were placed in a rotating autoclave similar to that used in Example I. Two tests were» con~ ducted, run. No. 3 at 275° C. and run No. Zlat 230° C'. An analysis of the products indicated that at least 50% of the 2,3-dimethyl.butenevl was isomerized to 2,3-dimethyls buten€~2 :=Wi’th very’ little polymerization, the extent of» poly. merizatiorfbeing of the order of about 3%. 2,403,439 5 2. A process for isomerizing 2,3-dimethyl bu tene-l to 2,3-dimethy1 butene-2 which comprises contacting 2,3-dimethyl butene-l under isomer Teen: II Isomerz'aatz'on of 2,3-dimethyl butane-1 to 2,3-di methyl butane-2 with dilute aqueous ammoni ization conditions with a catalyst comprising a dilute aqueous solution of ammonium chloride um chloride solution having a pH above about 3 but less than 7. 3. A process for shifting the position of the Charging stock: 2,3-dimethyl butene-l double bond in a mono-ole?nic hydrocarbon Run N o. 3 which comprises contacting said mono-ole?nic hydrocarbon at ole?n isomerizing conditions with Run No. 4 a catalyst comprising an aqueous solution of an Operating conditions: Time at operating conditions ____ __ 3 3 __ 275 230 4 Pressure, atmospheres __________ __ Temp., ° C ________________ __ 109-143 95-105 2,3-dimetl1yl butened ___________ __ 47. 2 44. 2 Water __________________________ __ N H401 __________________________ _ _ 51. 8 1. 0 54. 7 1. 1 Total _________________________ __ 100. 0 100. 0 Charge: Weight per cent: acid selected from the group consisting of hydro gen chloride and hydrogen bromide, said aqueous solution having a pH above about 3 but less 15 than 7. 4. An isomerization process ‘which comprises converting a normal alpha ole?n into the corre sponding normal beta ole?n by contacting said alpha ole?n at ole?n isomerizing conditions with Products, wt. per cent of 2,3-dimethyl butene-l: 2,3-dimethyl butene-2 ___________ __ 50.0 2,3-dimethyl butene-l (recovered). 33. 6 62. 7 32. 4 20 a catalyst comprising an aqueous solution of an acid selected from the group consisting of hydro gen chloride and hydrogen bromide and. main Loss+uncondensable gas 13. 1 1. 3 taining the pH of said solution above about 3 but Total _________________________ -100. 0 100. 0 below 7 to substantially avoid polymerization. 5. The process of claim 3 further character 25 The above examples indicate in a general way ized in that said aqueous solution is formed by the selectivity of the catalysts disclosed in this dissolving in water a hydrolyzable salt of said invention as to their in?uence on the shifting acid. of the position of the double bond of an cle?nic 6. The process of claim 3 wherein said mono Polymer ______________ __ .- O6 alcohols ____________ _ _ 3 3 3 6 ' ' hydrocarbon, since high yields of isomeric ole 30 ole?nic hydrocarbon comprises butene-l. ?n hydrocarbons are obtained with very little polymerization of the ole?nic hydrocarbons. We claim as our invention: 1. A process for isomerizing butene-l to bu 7. The process of claim 3 wherein said mono ole?nic hydrocarbon comprises 2,3-dimethy1 bu tene-l. 8. The process of claim 3 wherein said mono tuene-2 which comprises contacting normalrbu 35 ole?nic hydrocarbon comprises pentene-l. tene-l under isomerization conditions with a cat alyst comprising a dilute aqueous solution of am monium chloride having a pH above about 3 but less than 7. VLADIMIR N. IPATIEFF. GEORGE S. MONROE.