US2753384A - Hf-bf3 treating of normal alkylbenzenes - Google Patents

Description

July 3, 1956 A. P. LlEN ET AL HF-BFS TREATING OF NORMAL ALKYLBENZEJNEJS Filed Nov. 13, 1953 m swoz QIVISOdWOOJG @mit IN V EN TORS 1 Arthur Lien Dav/'0 A. McCau/ay 2,753,384 'Patented July 3, 195

HF-BFs TREATENG F NSRMAL ALKYLBENZENES Arthur P. Lien, Highland,llnd., and David A. McCaulay,

Chicago, Ili., assignors toStandard (Bil Company, Chicago, 11]., a corporation of Indiana Application November 13, N53, erial No. 391,876

.11 Claims. (Ci. 269-663) This is a continuation-in-part of our copending application Serial No. 306,648 filed August 27, 1952.

Broadly this invention relates to the transfer of n-alkyl groups, which are substituents of a benzene'ring, without isomerizingthe alkyl-group. Particularly this invention relates to the preparation of di-n-propylbenzene by disproportionating mono-n-propylbenzene.

Some commercial demand has arisen for alkylbenzenes wherein the alkyl group contains three or more carbon atoms which have a normal configuration of the alkyl "group; e. g., mono-nwpropylbenzene is of interest as a sourceoffl-methylstyrene. Various methods are known for-the alkylation of benzene with n-alkyl halides to produce a mixture of mono-n-alkylbenzene and poly-n-alkyL benzene. However, attempts to convert said mono-nalkylbenzene to the corresponding di-n-alkylbenzene invariably result in a "substantial isomerization of the alkyl group. Thus preparation of di-n-alkylbenzene as presently known involves low yields and substantial loss to side reactants, such as iso alkylbenzenes.

An object of the invention is the disproportionation of mono-'n-alkylbenzene to the corresponding di-n-alkylbenz'enes, particularly the meta-isomer thereof. A particular object is the preparation of di-n-propylbenzenes, :particularly meta-di-n-propylbenzene, in high yield by thedisproportionation of mono-n-propylbenzene. Other objects of the invention will become apparent in the detailed description.

In this process a normal alkylbenzene selected from the class consisting of propylbenzene, di-propylbenzene, butylbenzene and di-butylbenzene is contacted under substantially anhydrous conditions and in the substantial absence of reactive hydrocarbons with at least an effective amount'of BFa, preferably at least 0.5 mol per mol of alkyl groups present, and an amount of liquid HP at least sufficient to form a distinct acid phase, preferably between about to mols per mol-of alkylbenzene; the contacting is carried out at a temperature between about 10 C. and about +100 C. for a time at least sufficient to produce an appreciable amount of poly-n-alkylbenzene; the HF and BF are removed from the acid phase in order to recover -the poly-nalkylbenzene.

By operating for a sufiiciently short time at a defined temperature and with a mono-n alkylbenzene charge, the production of tri-normal alkylbenzene can be essentially eliminated.

The charge to the process contains normal alkylbenzenes selected from the class consisting of propylbenzene, butylbenzene and the correspondingdi-alkylb'enzenes. In order to obtain products containing only one particular alkylsubstituent, the feed must contain only either prop'yl or 'butyl groups in the reactive component.

When the di-n-alkylbe'nzene is the only desired product, the charge should contain only the corresponding -x'nono-'n-alkylbenzene. When the yield of the tfi-n-alkylhydrogen fluoride.

mum requirement of liquid HP has been met.

tproportionation reaction to take place.

benzene is to be maximized, the charge should essentially contain only the corresponding din-alkylbenzene.

In addition to the alkylbenzene, the feed may-contain non-reactive liquid hydrocarbons. It is to be understood 'that the term non-reactive liquid hydrocarbons is intended to mean those hydrocarbons which are liquid at operating conditions and which are inert to the action of the HF-BFa agent and do not participate -in-any reaction with the alkylbenzene charged. Examples of reactive hydrocarbons are olefins, xylene, di-ethylben- 'zene, ethyltoluene, ethylbenzene and isopropyltoluene. Examples of non-reactivehydrocarbons are: isopentane,

butane andhexane. 'It is preferred thatbenzene be absent from the feed as its presence has an adverseefiebt on the degree of disproportionation obtained.

The process utilizes substantially anhydrous 'liquid The liquid hydrogen fluoride shouId not :contain more than'about 2-0'r 3% of water. *Commercial grade anhydrous hydrofluoric acid is "suitable forthis process.

Under the conditions of the process, .poly alkylbenzenes form'a'complex containing 1 Il0f'BF3 and, it is believed, 1 mol of Therefore, at least enough liquid HF must be present to participate in the formation :of the complex with the poly-alkylbenzene; in aaditio'n to this amount, s'uflicient liquid HF must be prescut to dissolve the complex which has been formed. in general, the presence of a distinctsepar'ate acid-"phase in the contacting zone indicates that at'least the rriini- More than this minimum amount of liquid HP is desirable. Usually between about 3 and 50 mols of li'qtuid HF are utilized :per mol of secondary alkylbenzene charged to v th'e lIJIOCfiSS. 'It .is preferred to operate with between about 5 and 20 'mols 'of liquid HF per mol of alkylbenzene charged. V V

The process requires the presence of at least an amount of boron 'trifiuoride su'fiicient "to'c'au'se the dis- While amounts of fBEa as small as 0.1 mol per mol of normal alkyl :gr'oups' char -ged willcause an appreciable-amount ofdis- 'pr'oportiona'tio'n to take place, it 'is desirable to operate with .about'0.3 mol of BFs. still-moreBF has a benefioialeffect on the degree of the disproportionati'on reaction and as much as 5 or more mols may be used. When high purity meta-o'riented poly-n alkylbenzene -is adesired product, it'is preferred that at least 0.5 molof BFs should be used per mol of alkyl "groups "charged. For exa'rnplez with n-prop'ylb'enzene charge, 'atleast 0.5 mol-of BF should be used per mol of n-propylbe'nzene; with di-n pr'opylbenzene charge, at least 110 mol 'ofBFa should be usedper mol of 'di-n-propylbenzene charged.

When the feed to the process contains poly-alkylbenzenes, for example, tri-n-propylbenzene, in addition to the defined alkylbenzene, the BFa usage should'be, in ad- "ditionto that set out above, 1 mol per mol of said p'olyfalkylbenzene.

The process may be operated with two 'liquidphases present in the contacting zone. At high BFs usages, a gas phase may also be present in the contacting zone. The two liquid phases will be spoken of herein as the ra'flinate phase and the acid phase. The acid phase consists of liquid HF, BFs, complex and physically dissolved hydrocarbons. The raffinate phase may be nalkylbenzene in excess ofthat amount taken into the acid phase, or may be a mixture of n-alkylbenzene and inert hydrocarbons, or may be principally inert hydrocarbons. In the absence of substantial amounts'of 'ine'rt the substantial absence of inert hydrocarbons, all or virtually all the alkylbenzene will be taken into the acid phase either in the form of a complex or in solution. The presence of HF-BFs-poly-alkylbenzene complex in liquid HF very greatly increases the solubility of the liquid HF for aromatic hydrocarbons and increases slightly the solubility of paraflinic hydrocarbons.

The presence of a raifinate phase consisting principally of inert hydrocarbons, such as benzene and parafiins, has an adverse effect on the degree and direction of conversion of the n-alkylbenzene charged, even though theoretically sufiicient BFs is present to complex all of the poly-n-alkylbenzene formable from the n-alkylbenzene charged. A substantial amount of the n-alkylbenzene will remain in the rafiinate phase, even when using somewhat more than 0.5 mol of BFs per mol of n-alkyl groups charged. The alkylbenzene in the ratfinate phase does not undergo a rearrangement reaction to any significant extent, even under conditions of good agitation. (The presence of dissolved inert hydrocarbons in the acid phase does not appear to have any adverse effect on the degree or direction of the rearrangement reactions.)

In order to maximize the yield of conversion products, and to produce a di-normal alkylbenzene product fraction consisting essentially of 1,3-di-normal alkylbenzene, i. e., the meta isomer, it is preferred to operate under conditions which form a single essentially homogeneous liquid phase in the contacting zone. A single essentially homogeneous liquid phase is attainable with a feed containing as much as three volume percent of pnrafiinie hydrocarbons. Large amounts of benzene may be dissolved in the acid phase, as much as 1 mol or more, per mol of complexed poly-alkylbenzene, depending on the amount of complex in the acid phase. (It is to be understood that a separate gaseous BFs phase may also be present, but it is preferred that a minimum of free space be present in the contacting zone and that sufficient pressure be maintained to insure that essentially all the BFa is either in the complexed form or is in physical solution in the acid phase.)

The degree and direction of the disproportionation reaction are also determined by the temperature of contacting and the time of contacting; a definite relationship exists between the temperature, time and desired dispro- ,lportionat ion products. At temperatures much below about C. no appreciable disproportionation takes place even at contacting times of several hours. At temperatures of about +100" 0., side reactions such as cracking occur and the direction of the disproportionation changes; gas and a wide boiling range product mixture are obtained.

The contacting time has an important eifect on the course of the rearrangement reactions. At least sufficient time must be provided at the particular temperature of operation in order to obtain an appreciable amount of disproportionation products. As the contacting time is increased, at a constant temperature, the amount of disproportionation product increases. The disproportionation reaction appears to produce the di-alkylbenzene as the first product. Dependent upon the temperature, a finite period of time elapses between the appearance of detectable amounts of the di-alkylbenzene product and the appearance of the tri-alkylbenzene product. The lower the temperature of operation, the longer the time elapsed before the appearance of an appreciable amount of the tri-derivative.

With increasing contacting time, at constant temperature, the amount of tri-alkylbenzene product gradually increases at the expense of di-secondary alkylbenzene formed. Gradually the amount of the tri-derivative increases and eventually the tri-derivative continues to increase with simultaneous disappearance of the diderivative. At highter temperatures and prolonged contacting times, the reaction product mixture contains the ,4 tri-derivative as the predominant disproportionation reaction product. However, at prolonged contacting times at high temperatures, the cracking reaction goes on at the expense of the poly-alkylbenzene and the yield of poly-alkylbenzene decreases.

The disproportionation reaction can be controlled, within experimental error, to produce di-alkylbenzene as essentially the only poly-alkylbenzene product, by suitably adjusting the time and temperature of contacting. The lower the temperature of contacting, the longer the contacting time permissible to avoid the formation of detectable amounts of the tri-derivative.

Normal pr0pylbenzene.The propylbenzenes can be disproportionated at temperatures as high as about +100 C. By operating at times of 2 to 3 minutes, cracking and side reactions can be reduced to some extent. The desirable maximum temperature of operation is about C. and the maximum time of contacting at this temperature is about 30 minutes. By operating for prolonged times, it is possible to obtain a significant amount of disproportionation at temperatures as low as 10 C. or even somewhat lower. At about l0 C. the minimum contacting time should be at least 60 minutes.

At the higher temperatures mono-n-propylbeuzene disproportionates to a mixture of di-n-propylbenzene and tri-n-propylbenzene. When a mixture of poly-n-propylbenzene is suitable, the process is preferably carried out at a temperature between about +20 and about +75 C.; the contacting times should be between about 5 minutes and 6 hours, the longer times corresponding to the lower temperatures.

A reaction product mixture containing the di-n-propylbenzene as essentially the only poly-n-alkylbenzene can be obtained by operating for short contacting times at elevated temperatures, for example, about 5 minutes at +60 C. Longer times may be tolerated at the lower temperatures, for example, at +20 C. about 3 hours.

Normal butylbenzene.-The n-butylbenzenes undergo cracking and other side reactions more readily than the n-propylbenzenes. The upper temperature limit for nbutylbenzene operation is about C. at very short contacting times. The desirable upper limit of operation is about +60 C. and at this temperature the maximum contacting time is about 60 minutes. The practical lower limit for the disproportionation of n-butylbenzencs is about 0 C; at this temperature, a contacting time of at least about 60 minutes is needed to produce a significant amount of disproportionation.

When a product containing both di-n-butylbenzene and tri-n-butylbenzene is suitable, the mono-n-butylbenzene disproportionation reaction is preferably carried out at a temperature between about +20 and |60 C. at contacting times between about 20 minutes and 6 hours, the longer times corresponding to the lower temperatures.

The formation of the tri-n-butylbenzene can be avoided somewhat more readily than in the corresponding npropylbenzene reaction. When the di-n-butylbenzene is essentially the only poly-n-butylbenzene product, the reaction is carried out at a temperature between about +20 and |60 C. for a time between about 5 minutes and about 3 hours, the longer times corresponding to the lower temperatures.

Di-n-alkylbenzene.When the mono-n-alkylbenzene is the charge to the disproportionation process, an upper limit on the yield of the corresponding tri-n-alkylbenzene appears to exist. Even at high temperatures a considerable amount of the corresponding di-n-alkylbenzene is present in the reaction product mixture. The yield of the tri-n-alkylbenzene can be maximized by using the corresponding di-n-alkylbenzene as the feed. By operating at higher temperatures, it is possible to produce a reaction product mixture that consists substantially entirely of the tri-n-alkylbenzene and some tetra-n-alkylbenzene. By operating at lower temperatures and shorter 'propylbenzene and butylbenzene because weasel times the yield 'o't' the corresponding *t'e'tr'a n-alkylbenzene can be minimized. In'ge'neral, the temperature "of contacting for the di-n-alkylben'zene charge is preferred to be between about +20 and about +60 C. and the times 'of contacting are between about minutes and 3 hours, the longer times corresponding to the lower temperatures.

Even when using smaller amounts of BF3,the predominant di-n-alkylbenzene product is the 1,3-di-n-alkylben- 'zene, i. e., the meta isomer. The use-of 0.5 mol of BFs gives essentially pure 1,3-di-n-alkylbenzene as the di-nalkylbenzene product. By careful control of the contacting time it is possible to produce a di-rr-alkylbenzene product fraction which is, within the error of the analytical procedure, pure 1,3-di-n-alkylbenzene.

Under the conditions of operation described above, the tri-derivative is essentially pure 1,3,5-tri-n-alkylbenzene, i. e., the meta-oriented symmetrical configuration.

When the charge to the dim-alkylbenzene disproportionation process consists of mixtures of-Tthe meta isomer and at least one other isomer, which other isomer ispresent in substantial amounts, theacid phase contains a reaction product mixture wherein the di-n-alkylb'enzene fraction is enriched with respect to the meta isomer. When operating under essentially single liquid phase conditions and with at least 1 mol of BF3 per mol of di-nalkylbenzene charged, the reaction product'mixture contains essentially pure meta di-n-alkylbenzen'e as the n-alkylbenzene component, i. e., the ortho and/or pa'raisomers are isomerized to the meta isomer.

By operating at very low temperatures, e. g, ---20-C.,

and short times, or, at moderate temperatures, e. g., C., in the presence of added benzene, it is possible to isomerize the ortho and para di-n-alkylbenzenes essentially completely to the meta isomer, without a substantial amount ofdisproportionati'on reaction'taking place.

The invention is limited to the "HF-BFg treatment of successful treatment of the pentylbenzene requires'very different operating conditions.

The reaction product mixture may be recovered from the acid phase'by-various methods. 'Probably the simplest procedure and one most suitable for laboratory work consists of adding the acid-phase to crushed ice; or the acid phase may be contacted with cold aqueous alkaline solution, such as sodium hydroxide, potassium hydroxide and ammonia. It is desirable to prevent rearrangement reactions by the use of a cold aqueous reagent.

The hydrocarbons originally present in the acid phase appear as an upper oil layer above a lower aqueous'layer. The upper oil layer maybe separated'by decantation and may be treated with dilute aqueous alkalinesolution to remove any remaining HF and BF3 occluded therein.

Both HF and BF3 are relatively expensive chemicals and it is desirable in an economic process to'recover these and to recycle them for reuse inthe process. The HF and'the BF3 may be readily removed from the acid phase by heating the acid phase or by applying a vacuum thereto. The HP and BFa distill overhead and may be recovered for reuse in the process. When di-alkylbenzenes and/or tri-alkylbenzenes are the principal complexforming hydrocarbons, the complex may be decomposed at relatively low temperatures by "the use'of'vacuum distillation. The tetra alkylbenzene and'highenalkylben'zene complexes are stable and must be heated to relatively high'temperaturegtor' example, 150 C. or more in order to decompose the complex.

The rearrangement reaction proceeds from-the timethat the complex is formed until'the complex is decomposed, assuming that a suitable-temperatureexists. When it is desired to produce essentially only one rearrangement reaction product, 'for example, meta di-n-propylbenzene from h propylbenzene, it is necessary to take into ac- -count'the total time elapsing from the timethat the' com-.

plex has been" formed tillthe "time that it has been de- 6 composed in the distillative decomposition procedure. Thus, when using distillative decomposition procedure, it is necessary to consider the residence time of'the com- 'plex in the decomposing zone as a part of the contacting time. Also, it is necessary to consider the temperature maintained in the decomposing zone when a particular product or aparticular'ratio of products is desired. The distillative decomposing-zone may be operated at temperatures as-low as about 20 C. by-the use of high' 'vacuum therein. 'It is preferred to operate at temperatures of +60 0., or lower when the di-derivative is the desired product.

EXAMPLES The results obtainable by the invention are illustrated by severals examples set out below. The runs were carried out using a carbon steel reactorprovided with a 1725 R. P. M. stirrer. The order of addition of materials to the reactor was: (1) n-alkylbenzene of CP quality (2) commercial grade anhydrous liquid HF and (3) commercial grade BFs. The contents of the reactor were agitated during the addition of theHFan'd BF3; the agitation was continued while the reactor was brought to the desired-contacting temperature and maintained during theicontacting time. The contents of the reactor were withdrawn into avessel filled with crushed ice. An upper aqueous hydrocarbon layer formed above a lower aqueous layer. The hydrocarbon layer was decanted and washed with dilute ammonium hydroxide solution to remove HF and -BF3. The neutral hydrocarbons were water washed to remove traces of ammonium'hy'droxide.

the extract phase contained 24 weight percent. 'sultsshow that all the tri-n-propylbenzene remained in The reaction product hydrocarbons were fractionated in a laboratory distillation column provided with about 30 theoretical plates. Each product fraction was anar lyzed by a combination of boiling point, specific gravity,

the acid phase and about half of the di-n' propylbe'nzene remained in the acid phase. This runillustrates the fact that even'at' low temperatures, the use of small amounts of BB3 tends to produce'appreciable amounts ofthe triderivative.

In this test and all tests, the di-derivative recovered from the acid phase consisted of, within analytical'error, the meta isomer and the tri-derivative consisted, within analytical error, of the 1,3,5-tri-derivative.

Test 2 was carried out at a temperature the same as in test 1. However, a large excess of BF:; was present. This test showsthat even with alargeexcess of BFsand at a 30 minute time-10 minutes longer than the'total time in test l-no tri derivative was formed. The percent disproportionated in tests 1 and 2 also shows the favorable infiuenceof a single essentially'homogeneous phase in'the reactor and longer contacting time.

Test 5 shows that at a temperature of +103 C. a

- considerable amount of cracking and side reactions'have occurred, as evidenced by the large yield of'bicyclics and higher boiling material.

Test 4, which was carried out at +50 C., gave a 45% yield of the di-propylbenene-no tri-propylbenene-at an overall'percent disproportionation of 87%. These two tests show that operation at too high a temperature not only results in the predominance of the tri-derivative, but also results in a reduction in the overall yield of the di'-propylbenzene and tri-propylbenzene.

Tests 3 and 6 were carried out using n-butylbenzene as the charge. Test 3 shows that the n-butylbenzene disproportionates 'much more slowly than does n-propylbenzene. In test 2, 49% "of the n-propylbenzene 'was disproportionated, whereas under the same conditions in test 3 only of the n-butylbenzene was disproportionated.

Test 6 shows that n-butylbenzene undergoes side re- A single acid phase is withdrawn from the top of reactor 34 and is passed by way of line 41 into decomposing zone 43. The rearrangement reaction starts as soon as the HF, BFz, and n-propylbenzene are mixed and conactions to a greater extent at elevated temperatures than 5 tinues until the HF and BF3 are distilled from the acid does n-propylbenzene. Thus, in test 6, all the di-derivaphase. Therefore, the contacting time is measured as tive disappeared and only 9% of the tri-derivative was the time in mixer 31, reactor 3-4 and part of the total time present whereas about of the total reaction product in decomposing zone 43. In this embodiment, a total mixture consisted of the products of side reactions. On time of about 20 minutes is utilized. Under these conthe other hand, test 5 shows that under the same condi- 10 ditions only a very slight amount of tri-propylbenzene is tions, n-propylbenzene gives a yield of poly-propylformed. benzene and only half as much side reaction product as Decomposing zone 43 is provided with internal heater n-butylbenzene. 4 4 and some fractionation means, not shown. The tem- Table Test No 1 2 3 4 5 6 Charge:

n-alkylbenzene, type propyl propyl butyl propyl propyl butyl n-alkylbenzene,mols 2.16 1.29 0.75 1.67 2.50 2.25 HF/alkylbenzene, Ino1rati0 2. 9 13. 9 16. O 13. 8 14. O 11. 5 BF lalkylbenzene, mol ratio 0. 32 1. 62 2. 7 1. 49 1. 23 1.0 Temperature, O +5 +5 +5 +50 +103 +103 Time, Minutes- 1 1O 3O 30 30 30 Raf- Acid finate Phase Total Phase Reaction Product Mixture, mol percent:

Benzene 21 16 20 23 7 42 6O 60 n-alkylbenzene 66 34 60 51 85 13 5 11 1, 3-di-n-alkylbenzene 13 44 19 26 8 45 12 0 1, 3, 5-tri-n-a1ky1benzene O 6 1 0 0 0 13 9 Bicychcs 6 17 Higher boiling 4 3 Percent disproportionation 49 15 87 95 89 1 The contents were settled for an additional 10 minutes.

ILLUgTRATIVE EMBODIMENT perature of +50 C. at about atmospheric pressure in The annexed figure, which forms a part of this specifi- Zone 43 1S g ugh to readlly decompose the cation, shows an illustrative embodiment of a method H but b g enough to cause aPPYe of carrying out the invention to produce essentially pure 40 able further dlspmpbrbbbabbng 1,3-di-n-propylbenzene by disproportionating n-propyl- HF Vapor and B133 g Wltbdrawb from Zone 43 benzene which had been obtained by alkylating benzene and Passed by Wby of bne 47 Into heat exchanger In with propylchloride under mild conditions. The figure b exchanger '3 the HF Vapors are cbndebsefl and a is schematic and many items of equipment have been bqmd'gas stream P by Way of bne 49 mtb gas omitted Such as pumps, Valves, flew as these may be separator 51. BFs is withdrawn from gas separator 51 readily added thereto and is recycled by way of l1nes 53 and 29 to mixer 31. Feed from source 11 is passed by way of lines 12 and b mtrbduced m b i y y of 13 into heat exchanger 14. From exchanger 14 the feed, valved b 57 mm bbe Llquld H: 15 recycled by recycled mPrOPYlbenZene are passed by Way of line 16 Way of lines 61 and 26. Make-up is introduced from into line 17' source 62 by way of valved line 63 Into line 61.

Anhydrous liquid hydrogen fluoride, 9 mols /mol of I The bottoms fraction from decomposing zone 43 concharge, is passed from line 26, through heat exchanger slsts bf n'plfbpylbebzebb, 'P'P P benzene 27 and line 23 into line 17. Heat exchangers 14 and 27 and a verysllght amount of "P bP The raise the temperature of the charge and the liquid HF b frgfcbbn 1S yvlthdrawn and Introduced by a of to a temperature of about C. This tgmperamre l1ne 71 into fractionation zone 72, shown schematlcally is about 10 C. lower than the desired reaction temperabbrelbbenzene fracbbn 15 W 1thdraWI{ 9 storage by ture of C. way of line 74. A product fraction consisting of essen- The contents of line 1'7 are introduced into mixer 31 bally P b 13H5i'n'prcpylbbnzbbb is Passbd to storage by which is provided with heat exchanger means 32. BFs, Way of b A bbtwms F b of trbmpmpyl' 0.6 mol/mol of charge, from line 29 is introduced into benzene 1S wltbdmwl} by Way0t bne Uncbnvel'ted mixer Mixer 31 is an apparatus able to rapidly n-propylbenzene is withdrawn rrom zone 72 and recycled intermingle the charge, liquid HF and BE. The heat to the rbactlon b by y of b bexchanger means 32 withdraws the heat given off by th Thus having described the lnvention, what is claimed is: complex formation and prevents the temperature at the A P the pwbuctlon 0f P Y" Y discharge 6nd f mixer 31 i i above +50 C zenes, WhlCh process comprises contacting, under sub- An acid phase Censisting f liquid p di m d 0mm stantially anhydrous conditions, a feed consisting essenplex, hydrocarbons and BE? is discharged from mixer 31. tially of normal alkylbenzene Selectbd from the Class About 200 p. s. i. g. of pressure are maintained on the consisting of propylbenzene, di-propylbenzene, butylbensystem to keep the excess B1 3 in the acid phase. The zene, di-butylbenzene, mixtures of said propylbenzenes mixture is passed from mixer 31 by way of line 33 into and mixtures of said butylbenzenes, with at least enough reactor 34. liquid HP to form a distinct separate acid phase and with Reactor 34- is provided with heat exchanger means 36 and 37. To insure the maintenance of a substantially uniform temperature of +50 C. throughout the reactor, reactor 34 is provided with bafiies 38a, 38b and 38c and motor driven agitator means 39.

at least about 0.3 mol of BFs per mol of alkyl groups in said feed at a temperature between about 10 and C. for a time at least suflicient to form an appreciable amount of poly-n-alkylbenzene and recovering poly-n-alkylbenzene from said acid phase.

2. The process of claim 1 wherein said liquid HF is present in an amount between about 3 and S mols per mol of alkylbenzene in said feed.

3. The process of claim 1 wherein said BF; is present in an amount of at least 0.5 mol per mol of alkyl groups in said feed.

4. The process of claim 1 wherein said temperature is between about +20 and +60 C.

5. A process which comprises contacting, under substantially anhydrous conditions, a feed consisting essentially of mono-normal-propylbenzene, with between about 5 and 20 mols of liquid HF and at least about 0.5 mol of BFs, respectively, per mol of said propylbenzene, at a temperature between about -l0 C. and about +75 C. for a time suflicient to obtain at least an appreciable amount of poly-n-propylbenzene, and removing HF and BFs to recover a mixture of hydrocarbons containing said poly-n-propylbenzene.

6. The process of claim 5 wherein said temperature is between about +20 C. and about +75 C. and said time is between about 5 minutes and 6 hours, the longer times corresponding to the lower temperatures.

7. A process for preparing meta-di-n-propylbenzene, which process comprises contacting, under substantially anhydrous conditions, a feed consisting essentially of mono-n-propylbenzene with between about 5 and 20 mols of liquid HF and between at least 0.5 and about 3 mols of BFs, respectively, per mol of said propylbenzene, at a temperature between about +20 C. and about +60 C. for a time such that m-di-n-propylbenzene is essentially the only disproportionation product, and recovering essentially pure meta-di-n-propylbenzene from the reaction product mixture.

8. The process of claim 7 wherein the time is between 10 about 5 minutes and 3 hours, the longer times corresponding to the lower temperatures.

9. A process which comprises contacting, under substantially anhydrous conditions, a feed consisting essentially of mono-normal-butylbenzene, with between about 5 and 20 mols of liquid HF and at least about 0.5 mol of BFa, respectively, per mol of said butylbenzene, at a temperature between about 0 C. and C. for a time suflicient to obtain at least an appreciable amount of poly-n-butylbenzene, and removing HF and BF: to recover a mixture of hydrocarbons containing said poly-nbutylbenzene.

10. The process of claim 9 wherein said temperature is between about +20 C. and about +60 C. and said time is between about 20 minutes and 6 hours, the longer times corresponding to the lower temperatures.

11. A process for preparing meta-di-n-butylbenzene which process comprises contacting, under substantially anhydrous conditions, a feed consisting essentially of mono-n-butylbenzene with between about 5 and 20 mols of liquid HF and between at least 0.5 and about 3 mols of BF3, respectively, per mol of said butylbenzene, at a temperature between about +20 C. and about +60 C. for a time between about 5 minutes and 3 hours, the longer times corresponding to the lower temperatures, and removing HF and BFa to recover a reaction product mixture containing meta-di-n-butylbenzene as essentially the only poly-alkylbenzene therein.

References Cited in the file of this patent UNITED STATES PATENTS 2,528,893 Lien et a1 Nov. 7, 1950

Claims (2)

1. A PROCESS FOR THE PRODUCTION OF POLY-N-ALKYLBENZENES, WHICH PROCESS COMPRISES CONTACTING, UNDER SUBSTANTAILLY ANHYDROUS CONDITION, A FEED CONSISTING ESSENTIALLY OF NORMAL ALKYLBENZENE SELECTED FROM THE CLASS CONSISTING OF PROPYLBENZENE, DI-PROPYLBENZENE, BUTYLBENZENE. DI-BUTYLBENZENE, MIXTURES OF SAID PROPYLBENZENES AND MIXTURES OF SAID BUTYLBENZENES, WITH AT LEAST ENOUGH LIQUID HF TO FORM A DISTINCT SEPARATE ACID PHASE AND WITH AT LEAST ABOUT 0.3 MOL OF BF3 PER MOL OF ALKYL GROUPS IN SAID FEED AT A TEMPERATURE BETWEEN ABOUT -10* AND +100* C. FOR A TIME AT LEAST SUFFICIENT TO FORM AN APPRECIABLE AMOUNT OF POLY-N-ALKYLBENZENE AND RECOVERING POLY-N-ALKYLBENZENE FROM SAID ACID PHASE.

7. A PROCESS FOR PREPARING META-DI-N-PROPYLBENZENE, WHICH PROCESS COMPRISES CONTACTING, UNDER SUBSTANTIALLY ANHYDROUS CONDITIONS, A FEED CONSISTING ESSENTIALLY OF MONO-N-PROPYLBENZENE WITH BETWEEN ABOUT 5 TO 20 MOLS OF LIQUID HF AND BETWEEN AT LEAST 0.5 AND ABOUT 3 MOLS OF BF3, RESPECTIVELY, PER MOL OF SAID PROPYLBENZENE, AT A TEMPERATURE BETWEEN ABOUT +20* C. AND ABOUT +60* C. FOR A TIME SUCH THEAT M-DI-PROPYLBENZENE IS ESSENTIALLY THE ONLY DISPROPORTIONATION PRODUCT, AND RECOVERING ESSENTIALLY PURE META-DI-N-PROPYLBENZENE FROM THE REACTION PRODUCT MIXTURE.

Images