US 2475358 A
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Description (OCR text may contain errors)
Patented July 5, 1949 HYDROCARBON CONVERSION Robert J. Moore,
Berkeley, Grcensfelder, Oakland, Calif.,
and Bernard S. asslgnors to Shell Development Company, San Francisco, Calif., a corporation of Delaware Application September 3, 1946, Serial No. 694,532
3 Claims. l
This invention relates to the conversion of normally solid hydrocarbons. The invention relates more particularly to a process for the conversion of straight and branched chain normally solid paraffin hydrocarbons to branched and more highly branched chain paraiin hydrocarbons respectively. A particular aspect of the invention relates to the conversion of normally solid paraffln hydrocarbons to normally liquidk hydrocarbons of branched structure having substantially the saine molecular weight as the solid parailin hydrocarbons charged.
Processes disclosed heretofore directed to the treatment of normally solid hydrocarbons, such as paramn wax, and producing a purely hydrocarbon product, generally involve either a refining operation to remove undesirable impurities, resulting in a normally solid material of improved characteristics, or a more drastic conversion treatment resulting in the obtaining of a normally liquid product. The former usually comprise such steps as solvent extraction, fractional crystallization, clay treatment and the like, in which the structure of the hydrocarbon is unaltered, whereas the latter involve a step in carbon decomposition resulting in a Wide range of reaction products comprisingnormally gaseous and normally liquid products as well as solid hydrocarbons and carbonaceous materials is a generally predominant reaction. The primary decomposition, or cracking, of the normally solid hydrocarbons is edected thermally with or Without aid of a catalyst. Catalysts disclosed as promoting the hydrocarbon decomposition reaction include aluminum chloride, but, although aluminum chloride is known also to promote such reactions as the conversion or normal butane to isobutane in the absence of any substantial hydrocarbon decomposition at certain conditions, the edect of this catalyst in the presence of a higher paraffin is to favor the cracking reaction over the isomerization reaction. Thus, in the presence of normal pentane, aluminum chloride will cause the cracking reaction to predominate, and in the presence of still higher paramns, the cracking which hydro-7 reaction will generally prevail to an :increasing` degree over the isomerization reaction. Recourse is therefore had in the isomerization of normal pentane with aluminum chloride to the use of agents capable of suppressing the cracking reaction. The agents suppressing the cracking fof the lower boiling params, however, also suppress to some degree the isomerization of these materials. Since cracking proceeds at a progressively greater rate with increase of molecular weight of the paraiilns, the inordinately large amount of cracking suppressor required to inhibit eliectively the cracking of, for example, a Cs parafln, results in a concomitant suppression of the isomerization reaction to a degree rendering the isomerization on a practical scale of such more readily cracked parains very uneconomical. Normallyv solid hydrocarbons and waxes in particular are completely converted to lower molecular weight hydrocarbons and tarry complex sludges by a combination of cracking and polymerization, condensation and addition reactions. Therefore, the treatment of paraiiins of such high molecular weights with aluminum chloride on a practical scale without substantial extent of cracking has until now been held unfeasible.
In contrast to the methods resorted to heretofore in the treatment of normally solid parailn hydrocarbons, and notwithstanding the increasingly unfavorable behavior of the lower boiling parafns of progressively increasing molecular weight in the presence of aluminum chloride and a cracking suppressor, it has now been found that normally solid hydrocarbons, such as, for example, paraiim wax, can be catalytically converted to normally solid and/or normally liquid hydrocarbons of improved properties having the same molecular weight as the normally solid hydrocarbon charge, in the absence of any substantial degree of hydrocarbon decomposition, with the aid of certain catalysts comprising a modified metal halide of the Friedel-Crafts type in the presence of a cracking suppressor under the conditions fully described herein.
It is an object oi the present invention to provide an improved process for the efficient conversion of normally solid hydrocarbons.
Another object of the invention is the provision of an improved process for the efficient conversion or normally solid hydrocarbons to normally liquid hydrocarbons having the same molecular weight as the normally solid hydrocarbons charged.
Another object of the invention Vis the provision oi an improved process for the eilicient conversion of normally solid paraffin hydrocarbon-s of straight or branched chain structure to normally solid parain hydrocarbons of branched and more highly branched chain structure, respectively, having the same molecular weight as the normally `solid hydrocarbon charge.
Still another object of the invention is the provision of an improved process for the eicient conversion of normally solid paran hydrocarbons of straight and branched chain structure to normally liquid paramn hydrocarbons of branched and more highly branched chain structure, respectively, having the same molecular weight as the normally solid paramn hydrocarbons charged,
A further object of the invention is the provision of an improved process for the efficient conversion of normally solid paraflin hydrocarbons to branched chain normally liquid paraffin hydrocarbons having the same molecular weight as the normally solid paraffin hydrocarbon charged, and comprising high quality lubricants and diesel engine iuels.
Still another object of the invention is the provision of improved high quality lubricants consisting essentially of. branched chain parafllns combining a high viscosity index with a low pour int. poStill another object of the invention is the provision of improved high quality diesel engine fuels combining low pour point with relatively high ignition values.
A still further object of the invention is the provision of high quality microcrystalline wax. Further objects and advantages of the invention will become apparent from the following detailed description thereof.
In accordance with the process of the invention, normally solid hydrocarbons comprising, for d example, at least one straight or branched chain paraflin having at least seventeen carbon atoms to the molecule and which is solid at room temperature, is dissolved -in a suitable solvent. The resulting solution is contacted with a catalyst comprising a modified metal halide of the Friedel- Crafts type in the presence of a cracking suppressor `under conditions converting normally solid hydrocarbons to reaction products comprising normally solid and/or normally liquid hydrocarbons of branched and more highly branched structure, respectively, having the same molecular weight as the normally solid hydrocarbons charged, in the absence of any substantial hydrocarbon decomposition. By the term decomposition as used in the present specification and appended claims is meant the rupture of carbon to carbon bonds of the hydrocarbon molecule to result inthe formation of hydrocarbons of substantially lower molecular weight than the normally solid hydrocarbon charged, or recombination of hydrocarbon fragments to form higher molecular weight tars and sludges.
In order to set forth more fully the nature of hydrocarbons, such as the paraffin waxes produced synthetically in any of the known processes for the synthesis of hydrocarbons such as, for example,'the normally solid hydrocarbon materials obtained in the synthesis of hydrocarbons from carbon monoxide and hydrogen by the Fischer-Tropsch process or modifications thereof. A particularly suitable normally solid hydrocarbon charge comprises, for example, one or more parailin hydrocarbons having from seventeen to about 200 carbon atoms to the molecule which are solid at a temperature of about 20 C. The invention is furthermore not limited to the conversion of only the normally solid open chain paraflln hydrocarbons, but comprises within its scope the conversion of any isomerizable normally solid hydrocarbon lsuch as, for example, the normally solid hydrocarbons comprising an isomerizable alkyl group linked to an alicyclic or aromatic ring. y
Referring to the drawing, the normally solid hydrocarbon charge may be introduced into a suitable enlarged chamber such as, for example, chamber I0, provided with a suitable inlet for the solid hydrocarbons such as a hopper Il.
Within chamber I0 the normally solid hydrocarbon is dissolved in a suitable solvent. Preferred solvents comprise a normally gaseous or normally liquid material functioning also as the hydrocarbon cracking suppressor in the conversion zone of the process. Such solvent and cracking suppressor is introduced into chamber Ill from any suitabley outside source by means of a valved line l2. Suitable cracking Suppressors comprise any materials capable of suppressing the cracking of hydrocarbons in the presence of the catalysts comprising a modified metal halide of the Friedel- Crafts type, under the conditions of execution of the reaction. The cracking suppressors employed may be normally gaseous materials as well as normally solid materials which are liquid at the temperature of reaction or which can be adequately dissolved in materials liquid at the temperature of reaction. Suitable cracking supthe invention, it will be described in detail with reference to the accompanying drawing; wherein the single gure illustrates more or less diagrammatically one form of apparatus suitable for executing the process of the invention.
`The normally solid hydrocarbons converted in accordance with the process of the invention comprise, for example, the parailin hydrocarbons of normal or branched structure having at least seventeen carbon atoms to the molecule which are normally solid at room temperature. The normally solid hydrocarbon charge to the system may consist predominantly of a single hydrocarbon or a mixture of two or more normally solid hydrocarbons obtained from any suitable source. They comprise, for example, the hydrocarbon waxes, such as the paraffin waxes separated from naturally occurring petroleum, or other waxy material such as petrolatum, slop wax, ozokerite wax, wax from asphaltic or bituminous substances, or other hydrocarbon waxes. A desirable charge to the system comprises the normally solid pressors comprise, for example, the butanes, the cycloparaflins and alkyl substituted cycloparaiiins, such as cyclopentane, methylcyclopentane, ethylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane and ethylcyclohexane, binuclear alicyclic hydrocarbons such as decahydronaphthalene, hydrindan, methylhydrindan, bicyclopentyl, cyclopentylcyclohexane, bicyciohexyl, dimethylbicyclopentyl, dimethylbicyclohexyl, dicyclo alkyl methy,
anes, dicycloalkylethanes, perhydroanthracene, tricyclopentyl, dicyclopentylcyclohexane, cyclopentylbicyclohexyl, dicyclohexylcyclopentane, tricyclohexyl, and homologs thereof. Other suitable cracking suppressors include saturated terpenes, saturated dicyclopentadienes, adamantane, spirocycloparaflins, and homologs thereof.
A single cracking suppressor or a mixture of two or more cracking Suppressors may be employed. The cracking Suppressors need not necessarily be introduced into the system in pure or concentrated form, but may comprise other materials such as hydrocarbon diluents, or solvents for the cracking suppressor or wax charge, having no deleterious effect under the conditions of execution of the process. The cycloparafin cracking Suppressors, for example, may be introduced into the system in the form of cycloparafn concentrates obtained by separating a cycloparafin-containing fraction of naturally occurring or synthetically produced narrow boiling range froml line i4 into the conversion zone. The conversion zone may comprise any suitable reactor, or plurality of reactors, connected in series or in parallel, optionally in combination with soaking vessels or a zone of restricted cross-sectionalv area such as a coil. In the drawing, the reaction zone is represented by reaction chamber I5 provided with suitable stirring-means I6. Though the in- Y vention is in no wise limited by the type of reactor or reactors employed, those providing intimate contact of catalyst and reactant are preferred. It has been found that eicient execution of the process is materially aided by intimate contact, preferably in the form of an emulsion orv dispersion of catalyst and reactants.
Although the use of a normally gaseous or normally liquid cracking inhibitor is preferred for simplicity as the sole solvent medium for the normally solid hydrocarbon charge, the use of a solvent which is not necessarily a suppressorof the I man hydrocarbon in excess of about 1:-1 by weight and preferably in the range of from about 2:1 to about 8:1 by weight. Excellent results are obtained with the cycloparailin cracking suppressors employed in the ratio of suppressor to solid hydrocarbon `charge of from about 3:1 to 5:1 by weight.
- Within reactor I6 the reactants are contacted with a modified lsomerization catalyst which in the presence of the cracking suppressor will effect the conversion of normally solidhydrocar bons. Suitable catalysts comprise an isomerization catalyst comprising a modified metal halide of the Friedel-Crafts type. Modification of the catalyst is essential to the attainment of the objects of the invention. Thus the use of AlCh per se in the absence of inhibitor at a temperature of Y about 100 C. resulted in complete destruction of a cracking reaction may be resorted to in addition to the cracking inhibitor. Such additional solvent is employed to facilitate solution of the solid hydrocarbon wax in a mixture of inhibitor and solvent orto enable the use of an inhibitor possessing little if any solubility for the normally solid hydrocarbon charge. Such additional solvents comprise any suitable normally liquid solvent or Anormally gaseous solvent which is liquid under the operating conditions, capable of dissolving the V,normally solid hydrocarbon charge and having no adverse eiect upon the execution of the reaction. Suitable solvents' which may be employed in addition to the cracking suppressor comprise, for example, the parafns suchas propane, normal pentane, isopentane, neopentane, and hexanes.
The solvent, or solvents, employed in addition to the cracking suppressor, are introduced into chamber it by means of valved line it. When thus introducing solvent through line it into chamber ld, all or part of the cracking suppressor may be passed from line l2, through valved line l@ to reactor l5. The solvent other than'the cracking inhibitor is generally introduced into the system in an amount not cess of that necessary to maintain the `normally solid hydrocarbon in solution in the system.
To aid in dissolving the solid hydrocarbon charge, heating means such as, for example, indirect heat exchangers 2@ and il are provided to raise the temperature of the streams entering chamber lb through lines l2 and/or it.
The rate of introduction of cracking suppressor into the system is controlled to eect the suppression of any substantial amount of hydrocarbon decomposition within reactor l5. The proportion of suppressor introduced will vary within the-scope of the invention, depending upon the particular suppressor employed as well as the conditions and particular catalyst maintained in reactor l5. VA ratio ofinhibitor to normally solid hydrocarbon charge of from about 3:1 to 5:1 by by weight and higher may be employed. It is preferred, howeve particularly when employing hydrocarbons ascracking Suppressors. to maintain the ratio of Suppressors to normally solid substantially in exparain wax with which it was contacted. Addition of suillcient methylcyclohexane to suppress the cracking of the wax, on the other hand, will generally substantially completely suppress any conversion of the paralhn wax in the presence of aluminum chloride per se under the usual operating conditions. Of the catalysts comprising a modified metal halide of the Friedel-Crafts type, those comprising a halide of aluminum, such as the chloride or bromide or mixtures thereof are preferred. By the term modified metal halide employedthroughout the specication and attached claims, is meant a metal halide which has been modied by combining a portion of it with a reactive material to form a fluid medium in which the remaining metal halide and added HC1 can be dissolved or suspended in a catalytically active state. -The isomerization catalysts, comprising the modied metal halide, employed in the process of the invention, are obtained by combining a metal halide of the Friedel-Crafts type with a suitable modifying agent under conditions resulting in a combination of the metal halide with the modifying agent. The resulting combination may be in the form of an actual complex compound of the metal halide and the modifying agent or in the form of a loose combination in which no actual compound formation between the metal halide and modifier occurs, and the actual compositions and structures of which, because of their complexity, do not lend themselves to ready determination. Suitable modifying ,agents which are combined with Vmetal halides of the Friedel-Crafts type to result matic hydrocarbons as exemplined by benzene,"
toluene, dimethyl benzene, trimethyl benzene, ethyl benzene, triethyl benzene, propyl benzene, ethyl propyl benzene, the isopropyl benzenes, the normal butyl benzenes, the tertiary butyl benzenes, the amyl benzenes, the mixed alkyl benzenes, such as ethyl toluene, dipropyl toluene, etc.; aromatic hydrocarbon fractions such as kerosene extracts obtained by the extraction of kerosene with a solvent possessing preferential solvent action for aromatics; aromatic extracts derived from thermally or catalytically cracked, reformed, or dehydrogenated petroleum or synthetic petroleum fractions, cyclic olefins such as cyclopentene or cyclohexene; paramnic and olenic hydrocarbons of straight or branched chain structure; halogen substituted paraflln hydrocarbons such as propyl chloride and butyl chloride, organic carboxylic acids of the fatty acid series, such as formlc, acetic, propionic, butyric, oleic, napthoic and the like; ethers such as diethyl ether, ethyl phenyl ether, and the like: the esters, such as isobornyl acetate, pyroboric acetate, ethyl benzoate. and the like; organic nitro compounds of which the nitro-parailins, the nitroaralkyl and the nitro-isocyclic compounds such as nitrobenzene, nitronaphthalene. nitromethane. nitroethane, nitrocyclohexane and the like, are representative alcohols such as isobornyl, glycerine, phenol, ethyl alcohol, propyl alcohol, isopropyl alcohol, dodecanol and the like; the ketones of aliphatic, aralkyl. aromatic or mixed character, such as acetone, methyl ethyl ketone, methyl propyl ketone, acetophenone, ethyl phenyl ketone, benzophenone and the like, their homologues and substitution products aliphatic, aralkyl or aromatic carboxylic acid halides, particularly the aromatic carboxylic acid halides as benzoyl chloride, benzoyl bromide, etc.; organic sulphones, such as the aryl and the aralkyl sulphones as diphenyl sulphone, benzyl sulphone; organic compounds broadly possessing a dipole moment and capable of reacting with aluminum halides, such as aluminum chloride.
The catalysts comprising a modified metal halide are obtained by combining one or more of the above catalyst modifiers with the metal halide, such as aluminum chloride, and allowing the mixture to stand at room temperature or at an elevated temperature up to, for example, about 150 C., generally in the presence of an added hydrogen halide, for a sucient length of time to result in the formation of a liquid, or sludge, consisting essentially of an organo-metal halide complex.` Although the above modified catalysts consisting o f complex .reaction product containing the metal halide are preferred, the invention in in no wise limited in the manner in which the activity of the metal halide is modied.
Thus suitable modified metal halide-containing catalysts are obtained by contacting a metal halide, such as aluminum chloride, with a portion of the normally solid hydrocarbon charge in the absence of a cracking suppressor, thereby obtaining a complex reaction product comprising modied aluminum chloride. Another source of modified metal halide catalysts comprises the metal halide-containing complex reaction products obtained during the isomerization of lower boiling paraiins with a metal halide of the Friedel-Crafts type such as aluminum chloride. The aluminum chloride-containing complex mixtures or sludges thus rejected from processes isomerizing lower paraiiins which are completely spent with respect to their ability to promote the isomerization reaction are converted to suitable modified aluminum chloride catalysts for. use in the present invention by the addition thereto of fresh aluminum chloride.
Other methods of modifying the metal halides to render them suitable in the process of the invention comprise their combination with at least one other metal halide. Thus suitable catalysts comprise a solution of AlCls in molten SbCls; the melts consisting of AlCla in combination with a halide of one or more of the following elements: Na, K, or other alkali metals, Zn, etc.
The modified catalyst may be prepared, for example, by the introduction of the modifying agent and the metal halide of the Friedel-Crafts type, such as AlCls, into a chamber 22. From chamber 22 the modified aluminum chloride is passed to reactor I by means oi"v line 24. The ratio of catalyst to hydrocarbon within reactor I5 may vary Within the scope of the invention. Catalyst to normally solid hydrocarbonratios may range, for example, from about 1:20 to about 10:1, and preferably from about 1:4 to 4:1 b! volume. Higher or lower proportions of catalyst may, however, be employed within the scope of the invention.
The reaction is preferably executed in the presence of added hydrogen halide such as, for example, hydrogen chloride, which is introduced into reactor I5 by means of line 23. The hydrogen chloride is preferably added in suillcient amount to saturate the reactants in reactor Il therewith. A lesser or greater amount of hydrogen halide promoter may be employed, however.
The temperature within reactor IB is maintained in the range of from about 20 C. to about 150 C. and preferably from about 50 C. to about 120 C. Optimum results are generally obtained by effecting the reaction in the range oi' from about 70 C. to about 110 C. The temperature within reactor I5 is maintained by suitable heating means such as for example heat exchangers I3 and I1 in lines I4 and I9, respectively. Additional temperature controlling means not shown in the drawing to effect the addition or removal of heat from reactor I5 may be employed. Subatmospheric, atmospheric or superatmospheric pressures up to, for example, about atmospheres may be maintained in reactor I5. Pressures ranging, for example, from about atmospheric to about 25 atmospheres are generally preferred. The contact time of catalyst and normally solid hydrocarbon charge may vary considerably within the scope of the invention. Thus, contact times may range from about 5 minutes to about 2 hours. Optimum results are, however, obtained by maintaining a contact time in the range of from about 15 minutes to about 30 minutes. Higher or lower contact times may, however, be applied within the scope of the invention.
Under the above-defined conditions, straight and branched chain normally solid hydrocarbons are converted to normally solid and normally liq-I uid hydrocarbons of branched or more highly branched structure possessing the same molecular weight as the normally solid hydrocarbon charge from which they are derived, in the absence of substantial hydrocarbon decomposition. Thus the parailinic hydrocarbons having at least seventeen carbon atoms to the molecule which are normally solid at room temperature are converted to normally solid parafiins comprising microcrystalline waxes and normally liquid products comprising high quality lubricating oils and Diesel fuels having the same number of carbon atoms, but of more highly branched structure, than the normally solid paraiiin charge, in the absence of any substantial hydrocarbon decomposition. Without intent to limit the scope of the invention by any theories advanced herein to set forth more fully the nature of the invention, it is believed that the effect of the conversion carried out in reactor I5 is to increase the number of alkyl side chains of the normally solid hydrocarbons treated and that the products obtained consist essentially of branched chain hydrocarbons in which the alkyl side chains formed during the reaction consist substantially exclusively of methyl groups.
Effluent from reactor I5 comprising dissolved normally solid hydrocarbons, normally liquid hydrocarbons in the lubricating oil and Diesel fuel boiling range, cracking suppressor, catalyst and hydrogen chloride promoter, is passed through valved line 25 into a separating zone,
` from hydrocarbons for example a chamber 28. Within chamber 2B a lower liquid layer comprising catalyst is separated from an upper liquid layer comprising hydrocarbons. The upper layer comprising hydrocarbons, as well as any normally gaseous materials such as hydrogen chloride, is passed from chamber 26 through line 21 into accumulator 28.`
Liquid comprising catalyst is drawn from chamber 26 and returned through valved lines 30, 3l and 24 to reactor I5. Inlet 32 is provided for the addition of make-up aluminum chloride to the recirculating catalyst. Such addition is preferably controlled to provide sufllcient aluminum chloride to the system to combine with any excess catalyst modifier present. Catalyst withdrawn from chamber 26 through line 30 is passed in part through valved line 33 into drum 22 wherein it is subjected to reactivation or employed as a component in production of additional modified catalyst. Removal of spent catalyst from the system may be effected by continuous or intermittent withdrawal from valved In a modified form of operation at least a portion of the reactor effluent is diverted from line 25 through valved line 36 into a chamber 31, wherein at least partial separation of catalyst is effected. Hydrocarbons, atleast partially freed of catalyst, are passed from chamber 31 through valved lines 38 and "25 into chamber 26. Liquid comprising catalyst is Withdrawn from chamber '31 and passed through valved line 39 into valved line 3i. The use of at least two separating chambers is advantageous in view of the'desirability of maintainingintimate contact of reactants and catalyst in reactor l5. The maintenance of such a high degree of contact, preferably in the state of an emulsion, may require the use of the plurality of separators enabling a rapid `partial separation, under conditions favorable to such separation, in the first of the separators.
Normally gaseous materials comprising hydrogen chloride may be flashed intermittently cr continuously from accumulator 28 and through valved line 40 into line 23 leading to reactor i5. .f
Liquid comprising unreacted charge and react tion products, as well as cracking suppressor and dissolved hydrogen chloride, may be taken from 50 accumulator 28 and passed to any suitable separating zone capable of effecting the separation of normally liquid and/or normally solid reaction products therefrom. Any conventional methods involving one or more such steps as fractiona- 55 tion, solvent extraction, fractional crystallization, ltration, etc., may be employed therein. The particular method of product separation will of course be governed to some degree by the properties such as boiling ranges of the components 60 present in the reactor effluent. In the present illustrative presenta-tion of the invention, lproduct separation is shown for conditions in which the cracking suppressor. and the additional solvent,
if employed. are lower boilingr than the products 65 of the reaction. Liquid is drawn for accumulator 2t and passed through line 4i into fractionator t2. Within fractionator 42 a fraction comprising normally gaseous material such as hydrogen chloride and optionally at least a part of the 70 cracking suppressor, and solvent, if present, is taken overhead through valved line 32 and passed, at least in part. through valved line 23 to reactor i5. A valved line 44 leading into line 23 isprovided for the introduction of make-up hydrogen passed v45 l0 chloride into the system. Bottoms comprising normally solid hydrocarbons in solution in normally liquid hydrocarbons are taken from fractionator 42 and passed through line 45 into a fractionator 46. Within fractionator 46 a fraction comprising the cracking suppressor is taken overhead through valved line 41 and passed at least in part through valved line 48 into the cracking suppressor charge line I2. A liquid 'fraction comprising hydrocarbons in the diesel fuel boiling range and higher is removed from the lower part of fractionator 46 through valved line 50. Any material boiling between the overhead and bottoms, which may'have been introduced into, or fonnedwithin the system, is withdrawn from fractionator 46 through valved line 5| and eliminated from the system, or passed in part or entirely through valved line 52 into line i9. g
Bottoms from fractionator 46 withdrawn through line are passed through valved line 53 into a separating zone, such as, for example, a fractional crystallization zone 54. Within the fractional crystallization zone the hydrocarbon stream is fractionally crystallized in conventional manner, for example in the presence of a suitable solventsuch as, for example, methylethyl ketone introduced through valved line 55. Within fractional crystallization zone 54 there is separated from the hydrocarbon stream a normally solid fraction comprising unreacted normally solid hydrocarbons, which is eliminated through line 56 and recycled to the reaction zone by means not shown in the drawing. Within fractional crystallization zone 54 there is also separated a normally solid reaction product comprising normally solid hydrocarbons having the same molecular weight as the normally solid hydrocarbon charge but possessing a more branched structure.A This normally solid reaction product is removed from crystallization zone 54 through line 51. The normally solid reaction product may be recycled in part or entirely into reactor I5, by means not shown in the drawing, to undergo further conversion therein to a normally liquid product having the same molecular weight as the normally solid hydrocarbon charge. Remaining liquid products comprising hydrocarbons in the diesel oil and lubricating oil boiling range and ketone solvent are taken from fractional crystallization zone 54 and passed through line 5B into a fractionator 59. Within fractionator 59 there is separated a fraction comprising the ketone solvent which is taken overhead and recycled through line 60 to the fractional crystallization zone. Within fractionator 59 there is also separated an intermediate fraction boiling in the diesel fuel boiling range and a fraction boiling in the lubricating oil range, which fractions are removed therefrom through valved lines 6I and 62, respectively. y I
For the purpose of clarity, parts of apparatus, suoli` as, for example, pumps, valves, accumulators, reboilers, reflux circuits and auxiliary equipment not essential to a full and complete description of the invention have been omitted from the drawing. The separation indicated above as effected within certain fractionators shown in the drawing, may in practical operation involve the utilization of a greater number of fractionators.
The normally solid hydrocarbons comprised in the reaction products of the invention will vary to some extent with the molecular weight of the normallysolid hydrocarbon charge. Thus,
' about 150 are products. The proportion of normally solid rik action products obtained is, however, reduced in a controllable manner by increasing the contact time employed or by recycling the normally solid reaction product to the reaction zone. Thus, sufflciently long contact times and/or continuous recycling of the normally solid reaction products will result in the obtaining of reaction products consisting predominantly, or substantially completely, of only normally liquid hydrocarbons having the same molecular weight as the normally solid original hydrocarbon charge in the absence of substantial hydrocarbon decomposition.
The production of a more highly branched product from the normally solid hydrocarbon f charge in accordance with the process of the invention therefore enables the eiiicient conversion of the normally solid hydrocarbons to normally solid hydrocarbons of substantially different and improved properties. Thus a parailin hydrocarbon wax of straight or only moderately branched chain structure is converted to a normally solid hydrocarbon product comprising high quality microcrystalline wax. The microcrystalline waxes thus produced posses highly improved properties rendering them eminently desirable for use as coating, impregnating and waterproofing materials, for rubber compounding, polishes, molding waxes, and other uses where a plastic wax of improved tensile or binding strength is desirable. v
A particularly valuable aspect of the process of the invention resides in its ability to convert normally solid hydrocarbons whose presence is detrimental to the physical properties of the fractions or products in which they occur into exceptionally valuable normally liquid products which may be returned to the parent fraction with great benefit thereto or which may be used separately to obtain the full application of their special properties. Thus the process of the inventiongenables the substantiallycomplete conversion of normally ysolid hydrocarbons such as para-ihn wax to normally liquid branched parafns comprising high quality Diesel engine fuels and lubricating oils. 'I'he normally liquid products in the Diesel engine -fuel boiling range obtained in accordance with the process of the invention possess the highly advantageous characteristics of combining a high heating value with low pour point and high ignition quality. Thus Diesel engine fuels having a cetane number 0f about 80 to 100 are readily obtainable in accordance with the process of the invention. 'I'he pour point of these materials can be controlled by increasing the degree of branching of the product. Thus the pour point of a liquid reaction product can be decreased materially with only a relatively slight lowering of cetane number, by recycling it through the reaction zone. As an example, a normally liquidhydrocarbon product in the Diesel engine fuel boiling range having a pour point as low as 60 C. is readlly obtainable from normally solid hydrocarbons by means of the invention.
Normally liquid products of the process of the invention in the lubricating oil range combine a high viscosity index with a low pour point, thereby rendering them of particular value as lubricants or as components of lubricating oils and compositions. Oils having a viscosity index of readily produced in accordance l2 with the process of the invention. Their pour point is also controllable Within a wide range asin the case of Diesel fuels. 'I'hus the pour point of -liquid products in thelubricating oil -v range may be reduced further by recycling through the reaction zone without decreasing the molecular weight of the hydrocarbon and in the absence of any substantial hydrocarbon decompositionre- Normally liquid hydrocarbons in the lubricating oil range having a pour point of about `20 C. arereadily obtained in accordance with the process of the invention from normally solid hydrocarbons.
The liquid products of the invention are, however, of value not only as Diesel engine fuels, lubricants, and as components for such compositions, but are suitably employed wherever a branched chain hydrocarbon of high molecular weight is used. They are of particular value as spray oils and components of insecticides. A further particularly advantageous aspect of the invention resides in the obtaining of branched chain hydrocarbons of high molecular Weight in relatively pure form from readily available materials by a method in which control of the degree of branching of the final product is possible over an unusually wide range.
The following examples are illustrative of the process and products of the invention: f
EXAMPLE I A modied aluminum chloride catalyst was prepared by reacting 66.4 parts of anhydrous aluminum chloride with 46 parts by weight of toluene resulting in a fiuid sludge. One part of a purified hydrocarbon wax, comprising only n-CzsHsz was dissolved in one part by weight of decahydronaphthalene. The resulting solution was contacted with a portion of the modied catalyst at a temperature of ,C., a contact time of four hours and a ratio of catalyst to wax of 1:1 by weight.' 'I'he reactants were stirred at a rate to form an emulsion While passing a slow stream of hydrogen chloride therethrough. At the conclusion of this operation, the two phases were allowed to separate. The hydrocarbon layer was decanted and washed with hot water. Decahydronaphthalene was flashed 01T and unreacted wax separated from the oil by crystallization from' methyl ethyl ketone. properties of the starting Wax and the oil obtained areas follows:
Wax Oil Product Charge Distillation range, C. at 6 mm. Hg 180 to 209 Refractive index, un 1. 4329 l. 4303 Refractive index, nu 1. 4529 Gravity, di 0. 778 0.' 770 Pour point, C 10 l 53. 5 Molecular weight 366 352 Kinematic viscosity, 100 F. cs 10. 84 Kmematic viscosity, 210 F. cs 2. 88 3. 08 Viscosity index l Melting point.
EXAMPLE II ride catalyst under conditions substantially as set forth in the foregoing example. Hydrocarseparated from the catalyst, washed with hot Water and lighter materials comprising 13 the cracking inhibitor employed removed therefrom by distillation. Unconverted hydrocarbon wax was removed from the normally solid and normally liquid reaction products obtained by 14 weight of. aluminum chloride to 3 parts by weight of the catalyst sludge. The resulting modined aluminum chloride catalyst had a specific gravity of 1.4.
ucts revealed the presence of groups identifiable as 2, 3- and other methyl Yand the absence of any geminate or neo-type dimethyl groups. Ex-` cellent values forthe coelcient of friction were obtained with a four-ball machine according to the test as described in Lubrication Engineering, vol. l, No. 2, page (1945).
ExAMPLm III A modied aluminum chloride catalyst was prepared by reacting 2 parts of anhydrous aluminum with 5 parts by weight of tertiary butyl chloride at room temperature and allowing the mixture to stand 8 hours. To the resulting sludge there was added an additional 1 part by low temperature extraction thereof with methyl 5 A paramn wax averaging 25 carbon atoms per ethyl ketone. Remaining normally liquid and l molecule with a molecular weight of 350 and a normally Solid hydrocarbon reactlOn products melting point of 53 C. was contacted in a series were further separated by successive low temof separate runs with portions of the above pre- Denture extractlfm by methyl ethyl kFt'one at pared modiiied aluminum chloride catalyst in the temperatures indicatedgin the following table. l0 the presence of a hydrocarbon cracking suppl- V'I'he boiling range of the oil before extraction was son The Wax was dissolved m the cracking sup about 160 C' to about 203 C at 4 mm' of Hg ressor rior to contact with the catalyst The d had the following characteristics: p p an reactions were executed with a ratio of catalyst ViSOSity index ,130 15 to hydrocarbon of 1:2 by volume. The reactants Pouroitow- 6-7 were stirredA vigorously during the execution of Gravityfdi o -f 03134 the conversion and a. stream of hydrogen chloride Refractive index L45? was passed continuously through the reaction tieculf wight-E-l'o-fl'p 10382 zone. The time of contact, nature and amount Ki mtic isssity' it 210 F "CS" 2'88 20 of cracking inhibitor employed, `and conversion n m c y "es" to normally liquid hydrocarbons obtained for Separation of the reaction products by the low each run Aare indicated in the following Table A:
Y Table A C t t gilghtf tczgiveisan 0D IIR? Tecrcnp" Tim Cracking Suppressor Crcllgigg Iqrilinl-Iyl-I hrs. Suppressor drocarbons, to Wax per cent wt.
l 100 4 Methylcyclohexane..." 1:1 21.0 100 1 dc 1:1 10.0 :s 100 2:1 28.0 4.. 100 4:1 21.0 s 100 4:1 28.9 0 10o 4:1 29.1 7... 100 1.0 .d0 8:1 30.0 8... 50 4 .Decahydronaphthalene. 1:1 V18.5 'a 50 4 Dirnethylcyclo entancs. lzl 18.0 1D... 100 3 Decahydronap thalene 1:1 21.0
temperature extraction resulted ln the obtain- Unconverted wax was separatedfrom the noring of a normally solid hydrocarbon fraction mally liquid hydrocarbon reaction products by consisting of microcrystalllne wax, and three crystallization in methylethyl ketone; The oil normally liquid hydrocarbon fractions having thus obtained was stabilized by distillation, in the following properties: which material boiling up to 100 C. at 2 mm. of
mercury was removed from the liquid hydrocar- Exmc Y Reim@ oncrrrcicniol bon product. The oils obtained had the same non Pniff Pour point'oo. tive. Ffcm at molecular weights as the paramn wax employed TP-f Extracted I" o o as charge to the runs. The observed physical 8 C' 130 C properties of the composited oil thus lobtained Saum 26 bmw 5l M597 0,070 0066 had the following properties. -50..... -6 -g fr0-076 0-052 Density (1512" 0,806 gij 12 31 "(r'ril'r'i'ifg" "0"" Refractive index. 11D 1.4542 point)Y Pour point, C. -9 Viscosity at 100 F. cs 8.679 The hydrocarbons comprised in each of the Viscosity at 210 F. cs 2 705 four fractions indicated above were found to have Viscosity index 135 a molecular'weight corresponding substantially to that of the parailm wax charged to the process, EXAMPLE IV i namely 352. Infra-red examination of the prod- A high melting California Wax averaging 35 carbon atoms to the molecule, having a melting point of 77 C. and a molecular weight of 500, was converted by contact with a portion of the modified AlCla catalyst prepared as in Example III. The conversion was carried out at a. temperature of C. with a contact time of 3 hours in the presence 'of 1 part of methylcyclohexane to 1 part of wax charge by weight. A stream of hydrogen chloride was passed through the reaction zone and the reactants were stirred throughout the contact time. A conversion to normally liquid hydrocarbons of 18% was obtained in the absence of any substantial hydrocarbon decomposition. Low` boiling materials in the oil thus obtained were ashed therefrom.
y ture of 100 C.
Properties of the normally liquid hydrocarbon product thus obtained were as follows:
S. A. E. viscosity number 10 Kinematic viscosity at 100 F. cs-- 36.4 Kinematic viscosity at 130 F. 19.9 Kinematic viscosity at 210 F '7.2` Viscosity index 150 Molecular weight 500 Pour point, C. 0 EXAMPLE V A modified aluminum chloride catalyst indicated in the following table by the letter A was prepared by fusing together AlCla, ZnClz, KCl and NaCl in the following proportions by weight, respectively, '75.15:7.5:7.5.
A second modified aluminum chloride catalyst indicated in the following table "B was prepared by melting together AlClz, KCl and NaCl in the following proportions by weight, respectively, 8:1:1.
A third modified aluminum chloride catalyst was prepared by dissolving parts of AlCl; in 95 parts by weight of SbCla. The catalyst is indicated in the table by the letter 0.
Each of the modified aluminum chloride catalysts thus prepared was contacted with a separate portion of an n-Daraiilnwax, consisting essentially of normal paraffin hydrocarbons having 25 carbon atoms to the molecule, at a temperain thepresence of added hydrogen chloride and for a time of contact indicated in the following table. Prior to contact with the catalyst the wax was dissolved in an equal weight, of decahydronaphthalene. The reactants were stirred throughout the conversion period. No evidence of any substantial hydrocarbon decomposition was observed throughout the runs. The conversion of wax charged to normally liquid products is indicated in the followingtable:
Percent Contact Conversion .Catalyst Time, Liquid hrs. Hydrocarbone EXAMPLE VI ethyl ketone resulted in the following three fractions:
Weight:- P Extract Tem ratureoi pern our 1120 Viscosity Fraction Extrggtiona giltgtxl Pglt D Index traded 5o 42 -o 1.4508 132 2. a 24 27 1.4494 139 a residue at at 34 +45 1.4492 16o The temperature at which the reaction was executed, the total amount of wax reacted, and the amount of wax converted to hydrocarbon oil for each run are indicated in the following table:
Total Reaction Amount Conversion Temp., oi Wax Wax C. Reacted, to Oil,
Per cent Per Cent EXAMPLE VH Twenty-five percent of liquid paraiinic oil producedk as in Example III was blended with a Diesel fuel of 42 cetane number and tested. The
' cetane number for the blend was 51.5 and the In a series of separate operation/s, carried out I under substantially identical conditions except for the reaction temperature employed, separate y portions of the solution of wax in methylcyclohexane were contacted with a modified aluminum chloride catalyst. The catalyst was prepared as described in Example III. A contact time of one-half hour was used in each run and the reactants were stirred vigorously throughout the conversion period while passing a stream of hydrogen chloride therethrough. Upon completion of each run, catalyst was separated from rthe hydrocarbon layer by stratification and decantation. Methylcyclohexane was removed from the hydrocarbon layer by distillation. Normally solid hydrocarbons comprising unconverted wax and wax having a lower melting point, but
calculated cetane number of the added paraiinic oil made in accordance with the process of this invention was, therefore, 80.
'Ihe invention claimed is:
1. The process for isomerizing parain Wax which comprises dissolving paraffin wax in an amount of decahydronaphthalene at least equal to about an added by weight of said paraiin waxg, contacting said solution with a preformed toluene-aluminum chloride complex in a reaction zone at a temperature of about 80 to C. while agitating the reactants vigorously to maintain them in a state of emulsion, said preformed toluene-aluminum chloride complex being obtained by the interaction of hydrocarbons comprising toluene with anhydrous aluminum chloride, thereby converting parafiin wax to reaction products consisting essentially of parafn wax and normally liquid hydrocarbons which are isomeric in structure to said charged paraffin wax in said reaction zone, and separating paraiiin wax and normally liquid hydrocarbons isomeric in structure to said charged paraffin wax from the eiuence of said reaction zone.
2. The process for isomerizing paraffin wax which comprises dissolving paraiin wax in an amount of decahydronaphthalene equal to from about an added 200% to about 800% by weight of said paraffin wax, contacting said solution with a preformed hydrocarbon-aluminum chloride complex in a reaction zone at a temperature of from about 20 to about 150 C. while agitating the .reactants vigorously to maintain them in a state of emulsion, said preformed hydrocarbon-aluminum chloride complex being obtained by the interaction of a hydrocarbon with anhydrous aluminum chloride, thereby converting parain wax to reaction products consisting essentially of paraiiin wax and normally liquid hydrocarbons which are isomeric in structure to said charged parafiin wax in said reaction zone, and separating paraiiin wax, and normally liquid hydrocarbons isomeric in structure to said charged paraffin wax from the eiiiuence of said reaction zone.
3. The process for isomerizing paraffin wax which comprises dissolving parafln wax in an amount of cycloparaiiinic hydrocarbon solvent equal to from about an added 50% to about 1000% by weight of said paraffin wax contacting said solution with a preformed hydrocarbonaluminum chloride complex in a reaction zone at a temperature of from about 20 to about 150 C.
while agitating the reactants vigorously to mainzo tain them in a state of emulsion, said preformed hydrocarbon-aluminum chloride complex being obtained by the interaction of a hydrocarbon with REFERENCES CITED The following references are. f record in the le of thispatent:
UNITED STATES PATENTS Number Name Date 2,404,436 Crawford et al July 23, 1946 2,406,868 Tongberg et al Sept. 3, 1946 2,408,941 Mavity et al Oct. 8, 1946 2,414,371 Fragen et al Jan. 14, 1947 2,417,698 McAllister et al. Mar. 18, 1947