Патент USA US2131191код для вставки
Patented Sept. 27, 1938 ~ 2,131,191 - UNITED STATESIIPAITENTA OFFICE‘ 2,131,191 DISPERSION OLEFINES IN’ ACID POLY MERIZATION I Bruno E. Roetheli 'and- Eldon E. Stahly, Baton. Rouge, La., assignors to Standard Oil Develop- . ment Company, a corporation of Delaware ' Application October 24, 1936, Serial No. 107,322 7 Claims.‘ ‘(01. 196-10) The present invention relates to an improved cient height to hold at' least 3 ft. of acid when > process for producing polymers suitable for motor measured in the quiescent state, and it will be fuels and motor fuel constituents from normally understood that the level will rise considerably gaseous .ole?nes,‘ and more speci?cally to an im 5 proved method for effecting such polymeriza tion with sulfuric acid. The method will be fully understood from the following description and ~ the drawing. thereafter when the ole?ne is‘passed into the ma terial so that‘ the total height of the chamber should be at least 5 ft. and. preferably about 12 ft. A pipe 9 is provided at‘ the upper end of the . chamber for the withdrawal of the mixture of acid Referring to the drawing, Fig. 1 shows a sec and ole?ne. Pipe 8 may be jacketed with an ele 10 tional elevation of an apparatus for effecting ,ment 2| in whicha cooling ?uid may be cir polymerization or condensation of normally culated to maintain a uniform temperature of the 10 gaseous ole?nes by means of sulfuric acid and the exit materials or to cool the; same. ' Pipe 9 dis ?ow of material through the apparatus is in charges into the settling drum 22, which drum is dicated. Fig. 2 is a top cross-sectional view of the connected by means of line 23 to vent line l8. 15 ‘apparatus shown in Fig. 1 taken along the line A cooler in is provided to reduce the temperature X-—X. Figs. 3 and 4 are larger scale drawings of the mixture as it flows from the settling drum ‘ of the jets which are used to force the ole?nic 22 to the'separation drum II. Settling drum 22 material to be polymerized into the reaction is also provided with a draw-off line 24. chamber. ‘ In the separation drum theacid and the hydro) 2 The polymerizing action» of sulfuric acid has carbon materials are allowed to stratify; the acid 20, been long known, and more recently it has been - being heavier is ‘found in the lower layer. This employed to eifect the polymerization of lique?ed is removed by a pipe I2 and recirculated to pump normally gaseous ole?nes, especially isobutylene, to form dimers and trimers which are well suited, 2 especially after hydrogenation, for use as motor ‘fuels or for constituents of motor fuels. The present invention is an improved method for carrying out this reaction and related condensa tions between various ole?nes. - ‘ Turning to the drawing, in Fig. l the numeral I 3O denotes a feed line by which the liquid ole?nes such as isobutylene or mixtures of isobutylene with propylene, normal butylenes, amylenes or 3.3 L! other ole?nes are forced by means of the feed pump 2. The feed passes through one or the other of the two ?ne mesh screen ?lters 3 and 4 which are suitably ?tted with valved connections. so that the one may be'cleaned while the other is in, use. The material then passes by a pipe 5‘ into?" the lower portion of the polymerization 4° chamber 6, into which it is discharged at a high iii to the bottom of the polymerization chamber.' The upper layer, which consists of the polymer, unpolymerized ole?ne and such saturated hydro 25 carbons as may be present, is taken off by a. pipe l4 through a further cooler l5 to a collection vessel i6. Gas binding of the equipment is prevented by the vent lines I‘! and I8. If desired a part of the product from vessel i6 may be recirculated by, 30 pipe l9 and pump 20. . - - Figs. 3 and 4'illustrate the preferred type of the jets ‘I mentioned in connection with Figs. 1 and 2. These jets are preferably ‘replaceable as shown and are in the form of wide tubes narrowed at the‘ end to provide a hole of small diameter, so as to cause the liquid to attain an extremely high velocity in passing into the acid bath. This type of construction minimizes the pressure drop re quired for the operation. In Fig. 3 thejet is di 4.0 velocity through a plurality of jets ‘I, which will be 1 rected upwardly, which is the preferred form, while in Fig. 4 the jet is directed downwardly ' described more fully below. The arrangement of these jets is more clearly shown in Fig. 2, in against a plate la which may be the bottom of which it may be seen that the various jets are reaction vessel v6, ‘or may be a separate member‘ 4 approximately equally spaced from each other and so placed as to best receive the stream of hydro from the side walls of the vessel. , ‘ ‘ vThe reaction chamber 6 is surrounded by a jacket 8. for heating, but it will'be understood that other heating means may be employed if de carbon and reverse its ?ow, at the same time breaking it up into tiny droplets. From the above description of the apparatus, the operation‘ will be generally understood, but“ 50 sired. The reaction chamber is adapted to main- ' the conditions for best operation vary consider 50 tain a relatively deep bath of sulfuric acid, and ably depending upon the particular ole?nes in the therefore it should be constructed of materials . feed,'the. type of polymer desired, and other con~ capable of withstanding its corrosive action. The - 'ditions., The acid may be described generally as diameter of the chamber is determined by the‘ being maintained at polymerizing strength and- ' 56 number of’ jets required. It should be of sum temperature. Withv more dilute acids, ‘somewhat 2 2,181,191 higher temperatures are preferred and vice versa. There is also some variation depending on the particular oieiines used. In general, it may be stated that ‘sulfuric acid within the limits 50 to 80% by weight more or less is satisfactory for the purpose. Where it is desired‘ to polymerize merely the iso-ole?nes, for example isobutylene, '10 in the feed, the temperature should be main tained within the limits of approximately 70° F. to 150° F. but in bringing about copolymeriza The rate of ?ow of acid upwardly .through the reaction chamber proper is relatively slow and the hydrocarbon droplets rise quite rapidly through the acid. The flow of the acid is rapidly increased at. the top of the reaction vessel so that the reaction is substantially stopped when the mixture of acid and hydrocarbon leaves the reaction chamber by the'exit pipe. This effect may be enhanced by cooling the mixture as it is withdrawn ‘and if desired the withdrawal pipe 10 tion of the isobutylene with another ole?ne of the - may be packed with acid-resistant shapes so as straight chain type, such .as propylene or to assist the coalescence of the hydrocarbon. The butylene, higher temperatures‘ of the order of actual separation occurs in the drum from which the acid is withdrawn for recirculation and‘ the 200 to 300° F. are used. For non-selective poly polymer withdrawn for recovery. 15 ‘merization of olefines or oleflne mixtures, tem It has been found that by increasing the time peratures from 300 to 500° F. are employed. Super-atmospheric pressures should be employed of. contact by recirculation of a part of the poly with elevated temperatures in order to maintain mer by means of line I 9 and pump 20, other con '20 the normally gaseous hydrocarbons in the liquid condition. Pressures of 300.—600 lbs. per square inch are ordinarily ‘required at temperatures of 200-300° F. ' The above conditions for‘ the. polymerization are important, and are broadly known in the 25 prior art. It is necessary, however, to combine these conditions with the following speci?cations in order to obtain the best results. It has been ditions being the same, the yield of the codimer of iso and normal butylene is increased. Without such recirculation there is a substantial propor tion of 2,2,4 trimethyl pentene formed, appar ently by polymerization of isobutylene, but by recirculation this can be reduced and 2,2,3 tri methyl pentene substituted, apparently by the copolymerization of iso with normal butylene. At the same time such recirculation allows poly merization of normal butylene to form appreciable found that a single jet may be employed effec tively, and in that case the reaction vessel is best percentages of 3,4 dimethyl hexene 2. Under 30 between 6 inches and 12 inches in diameter. For the optimum conditions 'of acid height, strength, 30 commercial operations it is more desirable to use temperature and rate of flow through the orifice, a plurality of jets in a reaction vessel of larger this expedient is not absolutely necessary in order diameter. The jet diameter may vary from about to reach the theoretical codimer, but recircula 0.010 to 0.15 inch and the velocity at the throat tion is desirable where optimum conditions are 35 of the jet should be of the order of at least 40 feet per second. If the velocity is below this figure, or on the other hand, if the diameter of the jet is larger, the hydrocarbon tends to issue in a continuous stream and effective polymerization is 40 not obtained. For example, the yield drops off very rapidly because of the loss of interi'acialv area and consequent time of contact. When a plurality of jets is employed they should be spaced not employed. 35 . . Example 1 To illustrate the operation of the present in vention, an oleiine mixture consisting mainly of isobutylene and normal butylenes, the latter be 40 ing in excess, was forced through a jet into the bottom of a bath of 60% sulfuric acid. The temperature of the bath was maintained at 225° F. and a total pressure of 400 lbs. per square inch was employed to maintain the ole?ne in liquid condition. These conditions are adapted to‘form at least 6 inches apart, preferably 10-12 inches 45 apart, with a minimum distance of 4 to '6 inches from the side wall of the vessel. These latter copolymers of the isobutylene with normal dimensions are important because if the jets are . butylene, and the most effective operation would placed too closely together 'or toonear the side be one in which a yield from 175 to-200%, walls, there is too rapid coalescence of separately ' are produced ‘and the yield is effectively dimin ished. If it is ‘attempted to make this up by‘ increasing the height of the acid, it is found that an excessive amount of trimer results which is 55 likewise unde'irable. As indicated before, it‘ has 50 formed droplets, with the result that larger drops been found that these conditions can' be so balanced that an extremely effective polymeriza-* tion may be obtained with an acid height of 3 to 10 feet for the higher temperatures. indicated , 60 above, 200-500° FL, although it is preferred tov provide from 5.to 11 feet and to use lower tem ' peratures. This acid height, it will be understood, 65 is measured while in the, quiescent state, and it rises considerably during the‘ operation. The acid may be maintained in the reaction ve'sel'without any circulation or stirring, other than is obtained by the introduction of the hy drocarbon at high velocity. It has been found, 70 however, that while the acid itself appears to act wholly as. a true catalyst, still itv is gradually consumed through side reactions and should be made up from time to time. It is also founththat the most convenient method of carrying out} the 15 reaction is to circulate the acid as shown in Fig. 1. based on the isobutylene entering, is obtained 50 together with a practically ‘complete absorption of the isobutylene. The acid in the quiescentv state stood at a height of 3 feet in a vessel of 5 feet over all heightr Using a jet with a diameter of .018 inch, the ole?ne was forced in at different feed rates. . In‘ the table below, the feed rate, velocity at the jet orifice, the yield of polymer based on the iso‘ butylene originally present, are given together with the time of contact in minutes, estimated 60 from the jet size, feed rate and the like. These? times of contact were also checked against runs in which naphtha or other like hydrocarbons were dispersed through acid in a glass vessel in which the operation could be ‘put under direct 65. observation : Yield based Jet N°' diameter Fm mm 0313?: Liters/tour 1 .018 4 2 .018 - 8 3 . 018 14 _ _ ' Jet velocity - Contact time Percent FL/uc , 120 22. 2 l. 11 160 44.4 Minute: 1. 7i 180 77. 7 l. 82' 70 2,131,191 The ?rst run produced under low feed rate and consequently under a low velocity was such 3 inch in'diameter, 6 feet of acid appears to be perfectly satisfactory. as to produce a substantially continuous-stream Runs 4 and '7 should be particularly noted as ' of the hydrocarbon which eventually broke into relatively large globules of the liquid. It will be they appear to employ the best combination of conditions. The polymer yield is very close to that theoretically obtained by copolymerization. of isobutylene with normal butylene: moreover, the isobutylene was substantially completely con noted that the time of contact was only 1.1 min-' utes and the yield about 129% based on the iso butylene, which means either that the conversion per pass- was low and that while some copolymer verted to polymer. .10 was produced, it failed by far to reach the theo-' ‘ . » 10 Example 3 retically possible quantity. Analysis of the exit gas showed that 90% of the isobutylene in the feed had been polymerized together with 19% In order to further illustrate the e?ect of the jet velocity, some further runs are included in of the normal butylenes. the following table, beyond the ranges illustrated _ _ 15 In the second run, twice as much of the ole?ne ‘ was fed through the jet as in the previous run. above. 20 that the rate of flow had been increased twice over the previous _run,-the time of contact was also greatly increased due to the fact that very ' . coupled with the fact that a more effective poly; 30 'mer is obtained, that is to say, the polymerv is ‘.closer ‘to the theoretical copolymer. Analysis showed that 92% of the isobutylene was absorbed from the feed together with 33% of the normal _ butylenes. The increased throughput is very no ticeable, for example, the overall amount of polymer produced in the second run is about 2% times as much as that produced in the ?rst run. In the third run the rate is even higher and thevelocity is well within the preferred range. 40 .It will be noted that the polymer is even more effective because it approaches even more close- - ly the theoretical copolymer. Analysis shows that 94% of thu- isobutylene is converted along with 40% of the normal butylenes. The total 45 polymer produced under these conditionsis about ?ve times as much per hour as is obtained under} the slow rate of flow illustrated in Run No. 1. . ' ‘‘ Jet diam Feed rate Inches Liters/hr. Yield on i-C4H; Jet velocity FtJsec. 0. 023 0. 02s ' 12 18 _ 163 19s 0. 023 24 189 0.023 40 191 43 65 S5. 5 141 Example 4 25 To illustratethe polymerization of a normal ole?ne by the above processes, thefollowing ex periment was performed. The acid level was 3 feet in height at a temperature of 225° F.‘ 60% vsulfuric acid was used ‘and the feed comprised a 30 lique?ed butylene and butane. The feed con tained about 18.1% of normal butylene with less 7 than 25% of isobutylene. It was fed in liquid state through the jets having a diameter of .018 inch at a rate of 15 liters per hour, which corre- . 35 sponds to a jet velocity of 53.7 feet per second. The polymer produced amounted to 35.5% of the ‘ normal butylene contained in the feed and was based on an analysis of feed and exit products. The polymer consisted of about 86% dimer and 14% trimer, and began to boil at ‘79° F., 69% distilled over at about 300° F. and in the distilla- _ tion a recovery of 74% was obtained. The hydrogenated material had excellent blending value as an antidetonation agent. - Example 5 The following experiment was carried out to Example 2 In the following experiments the same mix illustrate the process of copolymerizing ole?nes containing three and four ‘carbon atoms.v The 50 tures of iso and normal ole?nes were used as in reactor was ?lled with 66% sulfuric acid at a _ the prior examples but a larger jet size was em ployed and the acid height was raised. As .be-_ temperature of 200° F., under 600 pounds per fore the temperature was 225° F., pressure 400 55 lbs. per square inch. Table I eter of .018 inch and the velocity of the lique?ed hydrocarbon through the jet was 43.2 feet per second. The analyses of the feed and the exit Run ' . No. Jet Glam‘ Acid ' height Feed rate 15 Table II The velocity here was therefore twice what it was before, and rose above the critical velocity‘ of about 40 feet per second. In spite of the fact much smaller droplets were produced. There was substantially no continuous stream of they 25 hydrocarbon and consequently very little co alescence. It will be noted that the' yield of polymer rose to 160% based on the isobutylene. This increase is quite remarkable in that it is ‘ Yield on isobutylene Jet veloc _ ity square inch of pressure. The jet had a ‘diam materials were as followsi ‘Fad I 'Exitgas (20 Inches - Feet ' Liters/hr. FL/uc. 1 0. 023 6. 5 12 163 43. 2 2 0.023 3. 0 v 12 134 43.2 3 0. 023‘ 6. 5 4 5 O. 023 0. 023 11. 0 3. O 6 18 192 64. 8 18 . 24 201 156 . 64. 8 86. 4 0. 023 6. 5 24 ' 187 86. 4 ‘ ' 7 O. 023 11. 0 24 191 36. 4 8 O. 018 6. 5 12 188 67. 2 9 O. 018 3. 0 12 180 * 67. 2 Percent 65 , From these analyses it can be seen that 43% These runs show ?rst that the '11 foot acid head is preferable to the 3 foot or 6.5 foot head. This is illustrated by comparison of Runs 1 to '7, al though the improvement in the ‘use of the 11 foot head over that obtained with the 6.5 foot 75 head is not very large, With the smaller jet,’.018 of the propylene present in the feed is extracted and converted to a polymer. 75% of the iso butylene present is likewise converted with 30% ‘of normal butylene. The product has a gravity of 55.0 A. P. I. and began boiling at 123° F.; 95% at 335° F.; the aniline point was 34° F.; color 14% (R). 'From the distillation curve it appears ‘ 15' 4 2,131,191 ‘ the ole?ne mixture in a lique?ed state into the ent, showing a large number of combinations of lower part of the acid baththrough a minute di ameter ori?ce having an ori?ce size within'the the-propylene with butylene and isobutylene. In subsequent experiments with various sized limits of 0.01 and 0.15 inchat a velocity in excess jets, it is foundthat a minimum acid height of 3 - of 40 feet per ‘second, whereby the liquid ole?ne to 5 feet and a maximum of about 10 to 12 feet is is dispersed in small droplets throughout the' acid, permitting the droplets to rise through the acid, preferable, especially for polymerization of iso rbutylene or copolymerization of iso with normal the, height thereof being at from about 3 feet to 10 feet when measured in the quiescent state, then butylene, the particular type of reaction depend 10 ing chie?y on the temperature used. With such separating hydrocarbons from the acid and re ‘ acid heights and a linear velocity of between v‘i0 covering the polymer. ' 4. In a process for the polymerization of a mix and 150 feet per second at the jet, it is possible to ture of iso- and normal ole?nes to produce poly closely approximate theoretical yields of diiso butylene or codimer of iso and normal butylene mers suitable for motor fuels, the improved steps 15 as the case may be, with nearly complete reaction which comprise maintaining'a bath of sulfuric of the isobutylene. Under these conditions only a acid at polymerizing strength and temperature ‘trace of isobutylene escapes in the exit liquor and within the range of 50-80% and 200-300° F., re the polymer itself contains less than 10% of spectively, forcing the ole?ne through a jet of from 0.01 to 0.15 inch in diameter at a rate in ex trimer. The present invention is not to be limited to any 7 cess of >40 feet per second and providing a height 20 20 of acid from about 3-10 feet when measured in a theory of the operation nor to the reactions in volved therein, nor to any particular acid quiescent state, then separating the hydrocar ' strength, temperature, or the like, but only to the bon from the acid and recovering the polymer following claims in which it is ‘desired to claim from the hydrocarbon. 5. A process according to claim 4 in which. the 25 25 the invention as broadly as the prior art permits. ' a great many individual hydrocarbons are prese We claim: , ‘ 1. In a process for polymerizing lique?edrnor mally gaseous ole?nes by means of sulfuric acid to form polymers suitable for motor fuels, the steps of maintaining a bath of sulfuric acid at pol ymerizing strength and temperature, forcing the sulfuric acid is passed at a slow rate upwardly through the reaction zone, the mixture of acid and hydrocarbon withdrawn rapidly from the re action zone into a separation zone, and in which the acid is recirculated from the separation zone 30 i to the reaction zone. 6. In a process for polymerizing lique?ed nor mally gaseous ole?nes by means of sulfuric ‘acid to form polymers suitable for motor fuels,,the step of second, whereby the liquid ole?ne ‘is dispersed in ‘maintaining a ,bath of sulfuric acid at polymeriz small ‘ droplets throughout the acid, permitting ing strength and temperatures, forcing the ole the droplets to rise through the acid, the height ?ne mixture in a lique?ed state into the lower ole?ne mixture in a lique?ed state into the low er part of the acid bath through a minute diam eter ori?ce at a velocity in excess of 40 feet ‘per , thereof being adapted to provide time for a sub part of the acid bath through a minute diameter stantial reaction of the ole?nes, then separating, ori?ce at a velocity in the range from about 40 feet ‘ to 150 feet per second, whereby the liquid ole?ne, 40 hydrocarbons from the acid and recovering the is dispersed in small droplets throughout the acid, polymer. ' ' 2. In a process for polymerizing lique?ed nor- ' permitting the droplets to rise through‘ the acid, mally gaseous ole?nes by means of sulfuric acid the height thereof being adapted to provide time, to form polymers suitable for motor fuels, the for a substantial reaction of the ole?nes, then separating hydrocarbons from. the acid and re 45 steps of maintaining a bath of sulfuric acid at pol ymerizing strength and temperature, forcing the covering the polymer. ole?ne mixture in a lique?ed state into the lower part of the acid bath through a minute diameter ori?ce having an ori?ce size within the limts of 50 0.01 and 0.15 inch at a velocity in excess of 40 feet per second, whereby the liquid ole?ne is dis persed in small droplets throughout the acid, per mitting the droplets to rise through the acid, the height thereof being adapted to provide time for 55 a substantial reaction of the ole?nes, then sepa rating hydrocarbons from the acid and recovering the polymer. ' 3. In a process for polymerizing lique?ed nor mally gaseous ole?nes by means of sulfuric acid 80 to form polymers suitable for motor fuels, the steps,of maintaining a bath of sulfuric acid at polymerizing strength and temperature, forcing ' ~ ‘ _ i ' _ 7. In a process for the polymerization of a mix ture of iso and normal ole?nes to produce poly mers suitable for motor fuels, the improved steps which comprise maintaining a bath of sulfuric acid at polymerizing strength and temperature within the range of 50 to 80% and 200 to 300° F., respectively, forcing the ole?ne through a jet of from 0.01 to 0.15 inch at a ratein the ranged from 40 feet per second to 150 feet per second and 55 providing an acid height of from 3 to 10 feet when measured in a quiescent state, then separating the hydrocarbon from the acid and recovering the _ polymer from the hydrocarbon. > BRUNO E. ROETHELI. ELDON E. STAHLY.