US3301917A - Upgrading of paraffinic hydrocarbons in the presence of a mixed aluminosilicate, platinum metal catalyst - Google Patents

Description

United States Patent C) UPGRADING F PARAFFINIC HYDROCARBONS IN THE PRESENCE OF A MIXED ALUMINO- SILICATE, PLATINUM METAL CATALYST John J. Wise, Arlington, Mass, assignor to Mobil Oil Corporation, a corporation of New York No Drawing. Filed Sept. 22, B64, Ser. No. 398,432 12 Claims. (Cl. 260683.65)

This invention relates to the upgrading by isomerization and/or hydrocracking of paraffinic hydrocarbons in the presence of a mixed alumino-silicate, platinum metal catalyst, in particular the hydroisomerization of normal paraffins to branched chain isomers in the presence of these mixed catalysts. In the absence of cracking these are essentially the same molecular weight as the charge. With cracking they yield a range of isoparaffins of lower molecular weight.

Heretofore, it has been known that the isomerization of normal paralfins, particularly n-hexane, to their equilibrium mixtures of branched chain isomers, substantially increases the octane rating of the paralfinic hydrocarbons. In general, the octane rating of the equilibrium mixture is affected by the temperature at which the conversion is effected; the lower temperatures usually producing the higher octane rating. In attempting to produce such equilibrium mixtures of isoparafinic hydrocarbons, several catalytic processes have been developed. Of these, two major processes are presently employed for the isomeriza'- tion of normal paraflins. The lower temperature process effects isomerization over an aluminum chloride catalyst. This process is costly to operate because of extensive corrosive effects caused by the acidic sludge formed from the aluminum chloride catalyst material, thereby requiring expensive alloy equipment. Moreover, moisture and high molecular weight hydrocarbons usually present as contaminants in the charge stock cause deterioration of the catalyst and necessitate its frequent replacement. The higher temperature process utilizes a catalyst such as platinum on a silica-alumina base to promote hydroisomerization of normal paraffins in the presence ofhydrogen at temperatures on the order of 700 to 800 F. At these high temperatures the equilibrium mixture of isomers is such that substantial recycling of a portion of the paraffin feed is necessary to obtain the desired improvement in octane ratings. Advantageously, in accordance with the process of this invention, the problems attendant to these prior art processes are substantially eliminated or avoided by the use of a dual (functional, mixed catalyst at low temperatures.

This invention contemplates the upgrading of normal paraflinic hydrocarbons by hy-droisomerization and/ or hydrocracking same in the presence of hydrogen and a mixed alumino-silicate, platinum metal catalyst; the aluminosilicate (natural or synthetic) having metal and/or hydrogen cations ionically bonded or chemisorbed within its ordered internal structure so as to produce a high concentration of acid sites (H+) uniformly throughout the catalyst. In addition, this invention concerns continuous hydroisomerization and/ or hydrocracking of normal parafiins for extended periods in the presence of hydrogen Patented Jan. 31, 1967 exchanged alumino-silicate having a defined pore size of about 13 A., and platinum supported on an alumina carrier under certain reaction conditions.

In accordance with this invention, it has been found that the hydroisomerization and/ or hydrocracking of normal parafiins can be effected in the presence of a mixed catalyst consisting essentially of a highly acid aluminosilicate portion and a hydrogenation component of a platinum metal supported on a thermally stable carrier at temperatures from about 200 to about 700 F., in either a liquid phase, a mixed liquid-vapor or a vapor phase.

Advantageously, the highly acid alumino-silicate portion suitable for the punposes of this invention may be prepared from several naturally occurring or synthetic alumino-silicates. In general, these alumino-silicates have exchangeable metal cations, -i.e. alkali metals and alkaline earth metals, which may he completely or partially replaced by conventional base exchanging with othermetal cations and/or hydrogen cations to produce the necessary high concentration of acid sites (created by bonding of a hydrogen cation) within their ordered internal structures. It will be appreciated that the acidic nature of an aluminosilicate as evidenced by its concentration of acid sites, increases proportionally to the extent that the exchangeable metal cations have been replaced with the exchanging cations.

However, some alumino-silicates are not stable to direct exchange with hydrogen cations or are not thermally stable after a portion of their exchangeable cations have been replaced with [hydrogen cations. Thus, it is often necessary to exchange additional metal cations with an alumino-silicates causes the formation of acid sites (H+) within its ordered internal structure prior to the inclusion of hydrogen cations. In effecting such stability, it has been found that certain polyvalent metal cations not only provide acid stability to the alumino-silicates but also increase their concentration of acid sites without subsequent addition of hydrogen cations. Thus, the presence of cations of these certain metals, especially those polyvalent metal cations having higher valencies, Within the alumino-silicate causes the formation of acid sites (H within their ordered internal structure. It is believed that these metals, especially those which have valences of three or more, produce acid sites within the al-umino-silicate because of the spatial arrangement of the A10 and SiO4 tetrahedra which make up the ordered internal structure of the alumino-silicates. Within certain alumino-silicates, Where nearly every other tetrahedron has an exchangeable cation site (usually an alkali metal or alkaline earth metal), a polyvalent cation (two valent and even some three valent cations) may be accommodated within chemical bond distance by two or three, respectively, neighboring cation sites. However, if this accommodation is not spatially feasible, it is believed that the polyvalent metal cation is hydrolyzed thereby reducing its valence by the addition of one or more (depending on its valence), hydroxy groups (OH)- and creating (from water molecules present in the alumino-silicate structure) a hydrogen cation (for each [OH]- group) which then occupies one of the sites vacated by the exchangeable cation. Thus, those metals having higher valences generally provide a higher concentration of acid sites. It will be appreciated that the formation of acid sites within an alumino-silicate may occur by base exchanging these metal cations with an existing alumino-silicate or during the formation of a synthetic alumino-silicate in an ionizable medium. In addition, it will also be appreciated that the degree to which an alumino-silicate has been base exchanged with these metals will also determine its conoentration of acid sites. Furthermore, it will also be appreciated that the high concentration of acid sites (H+) produced by these metals may be further increased by subsequent base exchange with hydro-gen cations or cations which are capable of being converted to hydrogen cations, I

such as the ammonium radical(NH The unique activity of the alumino-silicate catalyst for effecting conversion by isomerization and/ or hydrocracking is also dependent on the availability of the active cation sites. Accordingly, the defined pore size of an alumino-silicate is to be considered when preparing the mixed catalyst of this invention. Generally, the aluminosilicate should have a pore size above about 6 A. in diameter so that it can accept the normal parafhnic hydrocarbon compounds within its ordered internal structure and also accommodate the branched chain isomers produced by the process of this invention. Preferably, in order to accommodate the multibr-anched isomers of the larger molecular weight hydrocarbons, the pore size is from about A. to about 13 A. in diameter. It will be appreciated that the pore size desired for the aluminosilicate portion of the mixed catalyst will depend on the normal paraffin to be converted as well as the mixture of branched chain isomers being produced.

Typical .of the alumino-silicates employed in accordance with this invention, are several alumino-silicates, both natural and synthetic, which have a defined pore size of from 6 A. to A. within an ordered internal structure. These alumino-silicates can be described as a three dimensional framework of SiO.; and A10 tetrahedra in which the tetrahedra are cross-linked by the sharing of oxygen atoms whereby the ratio of the total aluminum and silicon atoms to oxygen atoms is 1:2. In their hydrated form, the alumino-silicates may be represented by the formula:

Mg o ZA1 O I WSlO Z yH O wherein M is a cation which balances the electrovalence of the tetrahedra, n represents the valence of the cation, w the moles of SiO and y the moles of H 0. The cation can be any or more of a number of metal ions depending on whether the alumino-silicate is synthesized or occurs naturally. Typical cations include sodium, lithium, potassium, calcium, and the like. Although the proportions of inorganic oxides in the silicates and their spatial arrangement may vary, effecting distinct properties in the alumino silicates, the two main characteristics of these materials is the presence in their molecular structure of at least 0.5 equivalent of an ion of positive valence per gram atom of aluminum, and an ability to undergo dehydration without substantially affecting the SiO and A10 framework.

One of the crystalline alumino-silicates utilized by the present invention is the synthetic zeolite designated as zeolite X, and is represented in terms of mole ratios of oxides as follows:

wherein M is a cation having a valence of not more than 3, n represents the valence of M, and y is a value up to 8, depending on the identity of M and the degree of hydration of the crystal. The sodium form may be represented in terms of mole ratios of oxides as follows:

Zeolite X is commercially available in both the sodium and the calcuim. forms; the former being preferred for the purposes of this invention. It will be appreciated that the crystalline structure of zeolite X is different from most zeolites in that it can adsorb molecules with molecular diameters up to about 10 A.; such molecules including branched chain hydrocarbons, cyclic hydrocarbons, and some alkylated cyclic hydrocarbons.

Other alumino-silicates are contemplated as also being effective catalytic materials for the invention. Of these other alumino-silicates, a synthetic zeolite, having the same crystalline structure as zeolite X and designated as zeolite Y has been found to be active. Zeolite Y differs from zeolite X in that it contains more silica and less alumina. Consequently, due to its higher silica content this zeolite has more stability to the hydrogen ion than zeolite X.

Zeolite Y is represented in terms of mole ratios of oxides as follows:

wherein W is a value greater than 3 up to about 5 and X may be a value up to about 9.

The selectivity of zeolite Y for larger molecules is appreciably the same as zeolite X because its pore size extends from 10 A. to 13 A.

Another alumino-silicate material found to be active in the present process is a naturally occurring zeolite known as mordenite. This zeolite has an ordered crystalline structure having a ratio of silicon atoms to aluminum atoms of about 5 to 1. In its natural state it usually appears as the sodium salt which is represented by the following formula:

N3 4024H2O Mordenite differs from other known zeolites in that its ordered crystalline structure is made up of chains of S-membered rings of tetrahedra and its adsorba'bility suggests a parallel system of channels having free diameters on the roder of 4 -A. to 6.6 A., interconnected by smaller channels, parallel to another axis, on the order of 2.8 A. free diameters. As a result of this different crystalline framework, mordenite can adsorb simple cyclic hydrocarbons, but cannot accept the large molecules which will be adsorbed by zeolite X and zeolite Y. As a consequence of this smaller pore size, it has been found that mordenite will be more rapidly deactivated than either zeolite X or zeolite Y at the operating conditions of the present process.

It will be appreciated that other alumino-silicates can be employed as catalysts for the processes of this invention. A criterion for each catalyst is that its ordered internal structure must have defined pore sizes of sufficient diameters to allow entry of the preselected reactants and the formation of the desired reaction products. Furthermore, the almumino-silicate advantageously should have ordered internal structure capable of chemisorbing or ionically bonding additional metals and/0r hydrogen ions within its pore structure so that its catalytic activity may be altered for a particular reaction. Among the naturally occurring crystalline alumino-silicates,.which can be employed are faujasite, heulandite, clinoptilolite, chabazite, gmelinite, mordenite and dachiardite. These silicates have been found to have the ability to absorb hydrocarbons containing more than three carbon atoms within their internal structure.

One effective highly acid alumino-silicate contemplated herein is prepared from the sodium form of zeolite X as the result of a conventional treatment involving partial replacement of the sodium by contact with a fluid medium containing cations of at least one of the rare earth metals, followed by additional exchange with a fluid medium containing hydrogen cations or a compound convertible to the hydrogen cation such as ammonium chloride. Any medium which will ionize the cations without affecting the crystalline structure of the zeolite may be employed. (It will be understood that the ammonium radicals are converted to hydrogen cations by a calcining treatment whereby ammonia is driven off from the exchanged zeolite material.) After such treatment the resulting exchange product is water washed, dried and dehydrated. The dehydration thereby produces the characteristic system of open pores, passages or cavities of crystalline alumino-silicates.

As a result of the above treatment, the rare earthhydrogen exchanged alumino-silicate is an activated crystalline catalyst material in which the nuclear structure has been changed by having metallic rare earth cations and hydrogen cations chemisorbed or ionically bonded thereto. It will be understood that a portion of the hydrogen cations found within the alumino-silicate result from the hydrolysis of the rare earth cations in a manner heretofore described.

Advantageously, the rare earths cations can be provided from the salt of a single metal or preferable mixture of metals such as a rare earth chloride or didymium chlorides. Such mixtures are usually introduced as a rare earth chloride solution which, as used herein, has reference to a mixture of rare earth chlorides consisting essentially of the chlorides of lanthanum, cerium, praseodymium, and neodymium, with minor amounts of samarium, gadolinum, and yttrium. This solution is commercially available and contains the chlorides of a rare earth mixture having the relative composition cerium (as CeO 48% by weight, lanthanum (as La O 24% by weight, praseodymium (as Pr O 5% by weight, neodymium (as Nd O 17% by weight, samarium (as Sm O 3% by weight, gadolinium (as Gd O 2% by weight, yttrium (as Y O 0.2% by weight, and other rare earth oxides 0.8% by weight. Didymium chloride is also a mixture of rare earth chlorides, but having a low cerium content. It consists of the following rare earths determined as oxides: lanthanum, 45-46% by weight; cerium, 12% by weight; praseodymium, 910% by weight; neodymium, 32-33% by weight; samarium, 5-6% by weight; gadolium, 34% by weight; yttrium, 0.4% by weight; other rare earths 12% by weight. It is to be understood that other mixtures of rare earths are equally applicable in the instant invention.

It will be appreciated that zeolite X may also be base exchanged with the rare earth metal cations alone if so desired, and that the resulting rare earth exchanged zeolite X will serve as an effective catalyst material; the primary difference being that its concentration of acid sites will be lower than the above-described catalyst material.

In accordance with this invention, a particularly effective alumino-silicate material for low temperature, vapor phase, hydroisomerization is the rare earth-hydrogen exchanged, crystalline, synthetic alumino-silicate zeolite X, but other alumino-silicates such as zeolite Y and mordenite may be treated to become effective catalytic materials for the process of this invention.

Zeolite Y may be activated by the same base exchange techniques employed for the rare earth-acid exchanged zeolite X catalyst. In addition, it has been found that the exchange of rare earth metals for the sodium cation within zeolite Y produces a highly active catalyst. However, because of its high acid stability the preferred form of zeolite Y is prepared by partially replacing the sodium cation with a hydrogen cation. This replacement may be accomplished by treatment with a fluid medium containing a hydrogen cation or a cation capable of conversion to a hydrogen cation. Inorganic and organic acids represent the source of hydrogen cations, whereas ammonium compounds are representative of the cations capable of conversion to hydrogen cations. It will be appreciated that the fluid medium may contain a hydrogen cation, an ammonium cation, or a mixture thereof, in a pH range from about 1 to about 12.

Mordenite is activated to serve as a catalyst for the instant invention by replacement of the sodium cation with the hydrogen cation. The necessary treatment is essentially the same as that described above for the preparation of acid zeolite Y.

In general, the mordenite is reduced to a fine powder (approximately passing the 200 mesh sieve and preferably passing 300 or 325-mesh sieves or finer) and then acid treated.

It will be appreciated that cations of polyvalent metals other than the rare earths having a valence of three or more may be employed to replace the exchangeable cations from the alumino-silicates to provide effective catalysts for this isomerization process. Exemplary of such metals are titanium, vanadium, chromium, manganese, iron, and the like. However, the chemical properties of the metal, i.e. its atomic radius, degree of ionization hydrolysis constant, and the like, will determine its suitability for exchange with a particular alumino-silicate.

In general, the hydrogenation component for the mixed catalyst includes a thermally stable carrier and a platinum metal impregnated or otherwise bonded thereto. Such platinum metals as osmium, iridium, palladium, ruthenium, rhodium and platinum, or mixtures thereof, have been found to be particularly effective. Preferably, because of its high hydrogenation activity, platinum is employed alone. In addition, it will be appreciated that other metals having hydrogenation activity may be utilized within the hydrogenation component. Examplary of these metals are chromium, molybdenum, tungsten, iron, cobalt, nickel, and the like.

The carrier for the platinum metal may be selected from any suitable material exhibiting thermal stability under the reaction conditions employed herein. Thus various refractory oxides, including alumina, silica, zirconia, magnesia, thoria, titania and the like, and mixtures thereof may be suitably employed herein. Typical of these oxide mixtures are silica-alumina, silica-alumina-magnesia, silica-zirconia, and the like. of the foregoing, alumina is preferably utilized and in particular alumina which has a high surface area of from about to 450 square meters per gram. As mentioned above, other hydrous inorganic oxides, binders, or similar catalytic supports may also be utilized as a carrier for the hydrogenation component, with carbon, activated charcoal, bauxite, kieselguhr, and the like being non-limiting examples of such alternates. One requirement for such carriers is that the carrier should have sufficient thermal stability to act as a support under the reaction conditions of this process.

The platinum metal or other hydrogenation metal may be impregnated in or bonded to the catalyst carrier by several conventional methods. For example, a carrier such as alumina is first calcined or dried to a water content of from 5 to 60 percent by weight, preferably 15 to 50 percent by weight. Then the carrier is treated with an aqueous solution containing platinum. Exemplary of such solutions are chloroplatinic acid, ammonium chloroplatinate, platinum chloride, and the like. Also nitrates, acetates and other ammonium complexes of the platinum metal may be used. The platinum is then converted to its elemental form by decomposing and reducing the impregnated compound with a reducing gas such as hydrogen at a temperature of about 750 to 975 F.

Another method is to impregnate the calcined carrier with a platinum solution. A precipitate of a hydroxide or carbonate is then formed within the carrier by the addition of an appropriate alkaline solution. The carrier is then washed substantially free of solution residue and subsequently dried, after which the precipitate is reduced by hydrogen gas, as previously described, to form the platinum metal.

The percentage by weight of platinum on the carrier is generally very small in comparison with the proportion of other active ingredients found within the mixed catalyst. Thus, the amount of platinum may extend from about 0.05 to 5.0 percent by weight of the mixed catalyst; preferably the amount of platinum metal is about 0.3 to 1.0 percent by weight.

It will be appreciated that these catalyst carriers have effective surface areas ranging from about 50 to 500 square meters per gram. The carriers, especially those having the higher surface areas, support and distribute the rel-atively small amount of platinum metal, so that it exhibits the hydrogenation activity necessary for the hydroisomerization and hydrocracking process of this invention. In addition, the carrier also performs another important function for the mixed catalyst. It .is believed that the use of a separate carrier for the hydrogenation component permits the alumino-silicate portion of the mixed catalyst to have the high concentration of acid sites necessary for the isomerization reactions of this process. That is to say, the carrier makes the platinum metal available to the parafiinic hydrocarbons without causing replacement of the metal cations and/ or hydrogen cations which produce the high concentration of acid sites within the aluminosilicate. Furthermore, the availability of the acid sites for contact with the parafiinc hydrocarbons is also maintained because the platinum metal cannot accumulate within the ordered internal structure of the alumino-silicate and thereby block off or otherwise reduce the effective diameters of its internal pore structures.

One outstanding effective mixed catalyst used in the process of this invention consists of an intimate mixture of equal proportions by Weight of a rare earth-hydrogen exchanged zeolite X (having only 0.22 percent by Weight of the sodium remaining) and a hydrogenation component of 0.6 per-cent by weight of platinum supported on alumina. This catalyst is formed by ball milling each component separately and then mixing the alumino-silicate and platinum hydrogenation component together in a ball mill. In addition, the mixed catalyst may be prepared by ball milling each component separately and then mixing the two components in the proper proportions within a matrix binder material.

The particular chemical composition of the latter is not critical; in fact it may be similar to the carrier used in the hydrogenation component. It is, however, necessary that the support or hinder employed be thermally stable under the conditions at which the conversion reaction is carried out. Thus, it is contemplated that solid porous adsorbents, carriers and supports of the type heretofore employed in catalytic operations may feasibly be used in combination with the mixed alumino-silicate, platinum metal catalyst. Such materials may be catalytically inert or may possess an intrinsic catalytic activity or an activity attributable to close association or reaction with the crystalline alumino-silicate. Such materials include by way of examples, dried inorganic oxide gels and gelatinous precipitates of alumino, silica, zirconia, magnesia, thoria, titania, boria and combinations of these oxides with one another and with other components. Other suitable supports include activated charcoal, mullite, kieselguhr, bauxite, silicon carbide, sintered alumina and various clays. Also, the mixed catalyst may be intimately composited with a suitable binder, such as inorganic oxide hydrogel or clay, for example by ball milling the prepared mixed catalyst and the binder together over an extended period of time, preferably in the presence of water, under conditions to reduce the particle size of the alumino-silicate portion of the mixed catalyst to a Weight means particle diameter of less than 40 microns and preferably less than l5.microns. Also, the mixed catalyst may be combined with and distributed throughout a gel matrix by dispersing it in powdered form in an inorganic oxide hydrosol. In accordance with this procedure, the finely divided catalyst may be dispersed in an already prepared hydrosol or, as is preferable, where the hydrosol is characterized by a short time of gelation, the finely divided mixed catalyst may he added to one or more of the reactants used in forming the hydrosol or may be admixed in the form of a separate stream with streams of the hydrosol-forming reactants in a mixing nozzle or other means Where the reactants are brought into intiate contact. The powder-containing inorganic oxide hydrosol sets to a hydrogel after lapse of a suitable period of time and the resulting hydrogel may thereafter, if desired, be exchanged to further introduce selected ions into the alumino-silicate portion of the mixed catalyst and then dried and calcined.

The inorganic oxide gel employed, as described above as a matrix for the mixed catalyst, may be the same refractory oxide used as the carrier for the platinum metal, such as, for example, aluminous or siliceous gels. While alumina gel or silica gel may be utilized as a suit-able matrix, it is preferred that the inorganic oxid gel employed be a cogel of silica and an oxide of at least one metal selected from the group consisting of metals of Groups IIA, III-B, and IV-A of the Periodic Table. Such components include for example, silica-alumina, silicamagnesia, silica-zirconia, sili-ca-thoria, silica-beryllia, silicatitania as well as ternary combinations such as silicaalumina-thioria, s-ilica-alumina-zirconia, silica-aluminamagnesia and silica-magnesia-zirconia. In the foregoing gels, silica is generally present as the major component and the other oxides of metals are present in minor proportion. Thus, the silica content of such gels is generally Within the approximate range of to 100 weight percent with the metal oxide content ranging from zero to 45 Weight percent. The inorganic oxide hydrogels utilized herein and hydrogels obtained therefrom may be prepared by any method well-known in the art, such as for example, hydrolysis of ethyl orthosilicate, acidification of an alkali metal silicate and a salt of a metal, the oxide of which it is desired to cogel with silica, etc. The relative proportion of finely divided mixed catalyst and inorganic oxide gel matrix may very widely with the mixed catalyst content ranging from about 2 to about 90 percent by Weight and more usually, particularly where the composite is prepared in the form of beads, in the range of about 5 to about 50 percent by weight of the composite.

The mixed catalyst employed in the process of this invention may be used in the form of small fragments of a size best suited for operation under the specific conditions existing. Thus, the catalyst may be in the form of a finely divided powder or may be in the form of pellets of to /s" size, for example, obtained upon pelleting the alumino-silicate and the hydrogenation component with a suitable binder such as clay.

It will be appreciated that the platinum metal of the hydrogenation component may be directly incorporated as a powder into a matrix binder containing the proper proportions of the highly acid alumino-silicate.

It will be further appreciated that the relative proportions of the high acid alumino-silicate within the mixed catalyst may be varied from about 90 percent by weight to about 10 percent by weight based on the total weight of the mixed catalyst. The specific proportion of acid alumino-silicate will depend on its effective acidity, that is, the concentration of acid sites found Within its ordered internal structure and their availability for contact with the paraflinic hydrocarbons. Likewise, the amount of hydrogenation component will be governed by its effective hydrogenation activity.

The paratfinic hydrocarbons which can be hydroisomerized in accordance with the process of this invention, may contain from 4 to carbon atoms per molecule. In .general, the straight chain saturated hydrocarbons with 4 to 8 carbon atoms are converted to mixtures containing a major proportion of monoand poly-branched chain isomers and only a minor proportion of lower molecular Weight cracked products. For example, the hydroisomerization of n-hexane in the presence of hydrogen and the heretofore described mixed catalysts produces a mixture of isomers such as 2,2-dimethylbutane, 2,3-dimethylbutane, Z-methylbutane and 3-methylpentane, together with lower molecular weight paraflins, i.e. propane, isobutane, n-butane, isopentane, and the like. In addition, other paraffinic hydrocarbons including those which have bnanched chains such as 2-methylbutane, 2-methylpentane, methylcyclopentane, methylcylcohexane, and the like, may be isomerized to compounds having a greater number of branched chains. As a result of the conversion from the straight chain configuration to a branched chain moiety, the paraffinic hydrocarbons in the gasoline range, such 9 as the n-hexane's, may increase their octane rating from about a leaded octane number of 65 to a leaded octane number above 90. As a result of theconversion from the straight chain to a branch chain moiety, the resulting isoparaflinic hydrocarbons in the C to C range subsequently find commercial use as special solvents as well as use in low pour-point diesel and jet fuels. Similarly, as a result of such conversion, the C C range isoparaffins have found utility as excellent synthetic lubricants. It will be appreciated that the extent of improvement in the products produced by the process of this invention, is de pendent on the paraffinic hydrocarbon being isomerized, as well as the particular operating conditions and specific mixed catalyst being employed.

In accordance with the process of this invention, high conversion of normal parafiinic hydrocarbons to their corresponding mixture of isomers, can be obtained at relatively low operating temperatures and non-corrosive conditions. The temperatures of the process may extend from about 200 to about 700 F.; preferably the process operates at a temperature from about 300 to 550 F. In general, the choice of temperature is dependent upon the paraffin being isomerized. The higher molecular Weight paraffins containing more than 8 carbon atoms usually are isomerized at the lower range of temperatures with the hydrocracking reaction quickly replacing the hydroisomerization reaction as the temperature is increased- For example, cetane containing 16 carbon atoms per molecule can be isomerized at temperatures as low as 325 F. However, at the lower temperatures, the conversion rate of the normal parafiins is comparatively low; thu requiring extended periods of operation for producing the desired yields.

As the temperature of the process is raised, the conversion of normal hydrocarbons rapidly increases, i.e. from about one percent to about 99 percent by weight. However, at the higher temperatures isomerization and cracking of the normal paraffins occurs yielding branched isomers of lower carbon numbers than are obtained at the lower temperatures. In addition, at the higher tem-, peratures, the significance of the hydrogenation component of the mixed catalyst becomes more important. Thus, it

has been found that a highly acidic alumino-silicate material such as rare earth-hydrogen exchanged zeolite .X

will effect isomerization of n-hexane at temperatures on the order of 500 F., but at these temperatures the rate of conversion rapidly drops off due to the aging of the catalyst. Apparently, this deactivation results from a rapid build up of cracked and degradation products produced by side reactions of the isomer at these elevated temperatures, thus reducing the availability of the acid sites for contact with the parafiinic hydrocarbons.

When a hydrogenation component is added to the alumino-silicate in the proportions necessary to form the mixed catalyst of this invention, the deactivation of the catalyst, even at high temperatures, is comparatively eliminated. As exemplified by the examples, a mixed catalyst,

prepared from a rare earthhydrogen exchanged zeolite X and platinum supported on an alumina carrier, undergoes only slight deactivation at the temperaturesof 500, F., and above. Apparently, the hydrogenation component prevents the reaction products from undergoing degradation and subsequent coking thereby clogging up and reducing the activity of the mixed catalyst material.

This process may operate at pressures from about atmospheric to several atmospheres. Preferably, the pressure is suflicient to maintain the paraflinic hydrocarbons in the liquid phase at the lower operating temperatures. In addition, even at temperatures above the critical temperatures of the paraffinic hydrocarbons, high pressure opera tion is desirable since the selectivity of the mixed catalyst for producing branched chain isomers is substantially improved. Apparently, the higher pressures, e.g. 400 p.s.i.g., reduce the formation of'cra-cked products by causing the cracking reaction to favor formation of the higher mo lecular weight compounds.

The amount of hydrogen present during formation of branched chain isomers in accordance with this process is governed by the nature of the paraffini-c hydrocarbons be ing reacted as well as by the nature of the reaction per se. Usually, the molar ratio between hydrogen and the hydrocarbon charge is slightly greater for the lower molecular weight hydrocarbons. In general, the molar ratio between hydrogen and the hydrocarbon may extend from about 1:1 to about 5:1. Accordingly, the more hydrocracking being done, the higher the hydrogen consumption and consequently the higher the hydrogen to hydrocarbon ratio employed.

At the lower temperatures involved in this process, the residence time of the paraffins within the catalyst as expressed in terms of hourly space velocities, may be con- 7 siderably varied. Usually the liquid hourly space velocity of the parafiins extends from 0.01 to 2 volumes/volume of catalyst/ hour. Preferably, the liquid hourly space velocity is from about 0.25 to 0.50.

It will be appreciated that the operating conditions employed by the present invention will be dependent on the specific reaction, i.e., hydroisomerization and/or hydrocracking being effected. Such conditions as temperature, pressure, liquid hourly space velocity, and the presence of hydrogen, will have important elfects on the process. Accordingly, the manner in which these conditions affect not only the conversion and nature of the resulting branched chain isomer products but also the rate of deactivation of the catalyst will be described below.

The process of this invention and the results obtained thereby, may be more readily understood by reference to the following examples which are illustrative of the reactants operating conditions, and the catalyst employed herein.

The runs described in the following examples were conduct-ed in either the vapor phase or liquid phase at atmospheric or superatmospheric pressures, respectively. Vapor phase operations were conducted in tubular reactors ranging from 50 cc. to 300 co. in size, electrically heated and containing a fixed catalyst bed. A mixed catalyst consisting of equal proportions of a rare earth-hydrogen exchanged zeolite X (containing 0.22 percent by Weight of sodium) and a 0.6 percent by weight platinum on alumina,

was used for the majority of the runs. This catalyst was which functioned to condense the liquid products. All

products were analyzed on a temperature programmed gas chromatograph using a 12 inch column of polydecene EAMPLE I In this example onerun was conducted continuously in the presence of hydrogen and the heretofore described mixed alumino-silicate, platinum catalyst for a period of 71 hours. Normal hexane and hydrogen (hydrogen/nhexane molar ratio of 1.5/1) ,were passed over the catalyst at 400 p.s.i.g., 400 F., and a hexane LHSV of 0.25 for 6 hours. Samples of the product stream taken after 4.5 and 5.5 hours showed that the conversion of n-hexane was about 5 percent. Then the temperature was raised to 500 F., and the conversion jumped to 68 percent, of which 94.2 percent by Weight was hexane isomers; the

1 1 1 2 balance, 5.8 percent by weight being lower boiling point terms of conversion of the n-hexane, the activity dropped hydrocarbons. from a conversion rate of about 68 percent to about 54 The run was continued at 500 F., for 18 hours. Durpercent. After another 15 hours at this reduced convering this period continuous sampling of the products was sion rate, the temperature was raised to 550 F. Again taken at measured hourly intervals. the conversion increased this time to about 73 percent.

Inspection of Tables 1 and 2 below further amplifies the selectivity and high conversion obtained by the process of this invention.

After 24 hours on stream an upset in the hydrogen rate caused the catalyst to lose .some of its activity. However, when the hydrogen rate was restored, the activity of the catalyst substantially returned to its previous level. Measured in Table 1 HYDROISOMERIZATION OF NORMAL HEXANE OVER RARE EARTH-HYDROGEN EXCHANGED ZEOLITE X PLATINUM ON ALUMINA MIXED CATALYST Conditions: 2

l-l /Hexane Ratio, 1.5/1 (molar).

Hcxane Space Velocity, 0.25 LHSV (downflow).

Time on Stream, hrs.

152817566 0 0 0 0 0 4-7 7 & 313

070666 3 84 n 0 5 0 N 151308 u 0 2 n 1 2 103645 2 018 0 0 5 010108 w m%0 0 O 1 2 123442 1 364 0 5 010108 N 0 0 s m 1 r h m 0 776798 1B7 71 n 0 m 5 01 02 09 4 5 w03 0 t 3 22 h N S 1 D 2 n 0 e m 203548 0 657 0 4 1 1 203744 3 728 0 5 QLQLQQ 0 0&00 0 1 4 12 0 1 1 n n 37 n O 0 u u n n 0 4 u h n 1 1 n m 3 286 0 3 n u 1 A! 55 n e 00 n 1 233 0 0 0 O h n 1 C u a c n p l u a: a m h h 2 n m S u u u n l n n n m .u H mm H e w n .U P w e 1m n n b n in am a m a tlm a IL n n e .ue e 0 n hh p wi 1 .1 a flu 1 U e .m ee yi l nmmme n e m vtum ll tm O .Eh p dd 6 l wh o o b wt mon T LINIBZJZ 3N H Analysis, percent wt.:

0 n a X e h e V 0 w d e m n B 2,3-dimethylbutane plus 2-methylpentane- 3methylpentane Tnqht Isobutane. Normal butane- Normal pentane 2,2rdimethylbutane m t 0 T Time on Stream, hrs.

2923994769 LA LQMQRMQW 00 3 2 7545913024 0 0 0 LL2 0 l 2 9 Analysis, percent wt.:

Total The following references are referred to in Table 1:

1 Catalyst a 50/50 (percent wt.) mixture of Baker 0.6% wt. Pic/A1 0 and rare earth-hydrogen exchanged zeolite X (0.22% wt. N a). 2 Run made in I unit.

4872 hours was 550 F. Octane of product at 550 F. was R+0 cc. and 90.5 R+3 cc.

3 Temperature-06 hours was 400 I*.; 7-47 hours was 500 F., 4 Octane of charge stock was R+O cc. and 65.7 R+3 cc. 5 At 22 hours hydrogen rate was unusually low.

Table 2 SELECTIVITY IN THE HYDROISOMERIZA'IION OF n-HEXANE OVER RARE EARTH-HY- DROGEN EXCHANGED ZEOLITE X, PLATINUM ON ALUMINA MIXED CATALYS'I Conditions:

Pressure, 400 p.s.i.g.

Space Velocity, 025 vol. Hexane/hr./vol. Cat.

Analysis, wt. percent Charge 500 F. 2 550 F. 5

Propane. 0.2 0.7 Isob n 1 1. 0 3. 9 Normal butane 0. 3 1. 1 Isop 1. 2. 9 Normal pentane 0. 4 0. 9 2, 2-dimethy1butane 9. 8 8. 7 2, B-dimethylnutane plus 2-methylpentane. 0. 1 41. 0 40. 1 3emethylpentane 4. 2 18. 6 19. 9 Normal hexane 4. 3 26. 5 21. 2 Heavier than normal hexane 1. 3 0. 7 0.6

100.0 100. 0 100.0 Octane No., R+3 cc 65.7 4 (87. 7) 5 90.5 Conversion, percent wt. of charge 68.4 73.8 Selectivity, percent wt.:

To cracked products- 5. 8 12. 8 To Ct isomers 94. 2 87. 2

Comparison of C Fractions Charge Equilibrium Product Equilibrium Product 2, 2-dimethylbutane 19. o 10. 4 17. 7 9. 7 2, 3-Dimethylbutane plus 2-methylpeutane 0. 1 39. 5 42. 7 39. 8 44. 7 3-Methylpentane. 4. 3 26. 5 19. 4 26. 0 22. 1 Normal Hexane 95. 6 15.0 27. 5 16. 23. 5

1 Catalyst is an equal wt. mix 01' Baker 0.6% wt. Pt/Alzoa and exchanged zeolite X (0.22% wt. Na).

1 Product after 8 hours operation at 500 F 3 Product after 24 hours operation at 550 F.

4 Calculated octane no.

5 Octane no. on composite of many samples taken at 550 F.

The large percentage of branched chain haxanes found within the reaction products shows that the mixed catalysts has high selectivity for promoting hydroisomerization of hexanes over an extended period of operation under the reaction conditions of the process without requiring regeneration. During the 71 hour run after the temperature was raised to 500 F., the amount of isoparaffins was consistently aboveabout 65 percent by weight of the products until the hydrogen rate was unexpectedly lowered (after about 22 hours on stream). Then, the amount of isoparaflins was reduced to about 29.9 percent by weight for a short period. However, when the hydrogen rate was corrected to its proper molar ratio with the hexane feed the regenerative ability of the mixed catalyst again restored the amount of isomer back to about 55 percent of the product. It will be appreciated that this regenerative ability of the catalyst to withstand fluctuations in reaction conditions without permanently losing its unique activity, as well as its ability to operate for prolonged periods, is a substantial improvement in the catalytic hydroisomerization of paranins.

Furthermore, it is of interest to note that the hydrogen required for the process has an inhibiting eifect on the cracking reactions attendant to the isomerization process. Thus, when hydrogen was present in. the proper IllUlaf proportions, the amount of cracked product, i.c. butane, i-sobutane, pentane and the like may be only in trace amounts. Normally, these low boiling products Vary from about 0.5 percent by weight to 8.0 'percent by weight of the reaction products; the major proportion being at the lower end of this range of percentages.

In addition, higher conversion at 500 F. or above, when the hexanes were in the vapor phase, indicates that such operation promotes the effective acidity of the catalyst by dispersing the hexanes and hydrogen more uniformly through the catalyst. Apparently, the effects of hydrogenation on isomerization reactions are more pronounced when the hydrogen and hexanes are thoroughly intermixed.

Another interesting feature of the present process is its product distribution of isoparafiins. A significant proportion of the isomer mixture contains highly branched isoparaflins such as 2,2-dimethylbutane and 2,3-dimethylbutane. As a result, note Table 2, a substantial increase in the octane rating of the hexane feed stream is produced by the high selectivity of the mixed catalyst. At 500 F., the resulting products have a high octane rating of about 88, while at 550, the octane number is about equilibrium, conditions being closely approached.

In addition, the product distribution throughout the en.- tire run remained substantially constant at each temperature thus eliminating frequent regulation of leaded additive in producing the desired octane numbers and facilitating easier process control.

Likewise, conversion of the hexanes, as illustrated by both Tables 1 and 2, also remained consistent for extended periods of operation at each temperature level.

The selectivity of the mixed catalyst for promoting hydroisomerization, however, is higher at 500 F., than at 550 F. It will also be seen that the selectivity of the catalyst (referring to Table 1) increases with use and that during prolonged periods of operation the increase of selectivity can be readily discerned.

Accordingly, it will be appreciated that the preferred operating temperatures for producing branched chain hexanes in accordance with this process extends from about 400 to about 600 F.

EXAMPLE II The significant eflects produced by the hydrogenation component of the mixed catalyst are illustrated by this example. The operating conditions and procedures employed in Example I were used to isomerize n-hexane in the presence of hydrogen and a catalyst prepared from the alumino-silicate portion of the mixed catalyst. (A rare earth-hydrogen exchanged zeolite X, having a sodium content of 0.22 percent by weight.)

The first run was conducted at 400 F., for 12 hours,

portion of the more active acid sites within the aluminosilicate; thereby substantially reducing its unique activity for isomerization of the n-hexane. In fact, the activity of the catalyst was so reduced that at the end of the 12 With samples being taken at 2 hour intervals. Initially 5 hour period only about 7 percent of the n-hexane Was the conversion of hexane was about percent but after being converted to the branched chain hexane products. 12 hours on stream, the conversion dropped to about 7 The second run again showed that the alumino-silicate percent. The second run at 500 F., also produced an rapidly loses its activity without a hydrogenation compoinitial high conversion (68 percent), but after 13 hours nent. Higher conversion of the n-hexane was obtained on stream it was reduced to about 11 percent. As shown 10 when the temperature of the process was above the critical by Tables 3 and 4 below, the active life of this catalyst temperature of the hexane. At 500 F., conversion of was substantially shorter than that of the mixed catalyst. n-hexane initially was about 68 percent which was sub- Table 3 HYDROISOMERIZATION OF NORMAL HEXANE OVER RARE EARTH-HYDROGEN EXCHANGED ZEOLIIE X CATALYST (LIQUID PHASE) Conditions: 1

Temperature, 400 F. Pressure, 400 p.s.i.g.

H lHexane Ratio, 1.5/1 (molar). Hexane Space Velocity, 025 LHSV (downfiow),

Time on stream, hrs. Charge Analysis, percent wt.:

Lights 0. 04 0. 5 0. 1 0. 1 0. 1 3.7 1.2 0.6 0.2 01 01 0. O1 0. 4 0. 1 0. 1 3.8 1.3 0.7 0.2 0 1 0.1 0. 04 0. 4 0. 1 O. 1 1.2 0.5 0.4 0.1 0.1 0.1 2,3-dimethylbutane plus 2-methylpentane. 18. 4 14. 6 12. 1 9. 3 7. 5 7, 3 3-methylpentane 3. 8. 7 6. 9 5. 5 4. 0 3. 3 3. 2 Normal hexane 94. 9 60. 7 73. 5 79. 0 84. 6 87. 3 88. 1 Unidentified. 0. 2 0. 1 0. 1 Do 0.22 0.7 0.9 0.6 0.5 0.3 0.3 Do 1.14 0.3 0.7 0.7 1.0 1.0 0.8

1 Run on I unit.

Table 4 HYDROISOMERIZATION OF NORMAL HEXANE OVE(I;AI%II {EPII&1% H-HYDRO GEN EXCHANGED ZEOLITE X CATALYST Conditions: 1

Temperature, 500 F. Pressure, 400 p.s.i.

g. H lHexane Ratio, 1.5/1 (molar). Hexane Space Velocity, 0.25 LHSV (downfiow).

Time on Stream, hrs.

Charge 1 3 5 7 9 11 13 Analysis, percent Wt: 0 1 0 O5 0 05 0 1 0 1 Lig ts Propane. M4 U M i 0.3 0.1 0.1 0.1 0.2 Is0butane 10. 5 1. 7 0. 7 0.5 0.5 0.5 0. 4

Normal butane 0. 01 2. 6 0. 5 0. 2 0. 1 0. 2 0. 1 0. 2

Is0pentaneg 12. 1 1.8 0. 8 0.5 0. 6 0. 5 0. 5

Normal pentane. 0. 04 2. 7 0. 2 0. 2 0. 1 0. 1 0. 1 0. 1

12,2-dimethylbutane 3. 9 0. 5 0. 3 0. 2 0. 3 0. 3 0. 3

2,3-dimethy1butane plus Z-methylpentane--. 23.3 15.4 10.5 10.2 11.5 12.1 11.6

:3-methylpentane 3. 65 11. 7 7. 3 5. 0 4. 9 5. 7 5. 3 5. 6

Normal hexane 94. 9 28. 2 70.8 80. 0 82. 0 79. 8 79.9 80. 2 Unidentified 0. 3 0. 1 0. 1 0. 05 U. 05 Do 0. 22 2.2 0.6 0.5 0.0 0.4 0.3 0.2 Do- 1.14 1.4 0.6 0.7 0.7 0.7 0.7 0.6

1 Run in I unit.

Inspection of the above tables reveals that during the stantially the same as that produced by the mixed catafirst run, conducted at 400 F. when hexane was in a lyst. However, during 3 hours on stream this conversion liquid phase, the presence of cracked products, i.e.. lower dropped rapidly to about 24 percent. Moreover, as the boiling point hydrocarbons, was initially high, causing run continued, the conversion continued to drop until it;

rapid formation of degradation products within and on the catalyst. Samples taken at measured intervals indicate that the conversion rapidly decreased while selectivity for the branched chain paraflinic hydrocarbons increased over the 12 'hourperiod. Apparently, the initial rapid accumuwas only about 11 percent by weight of the charge after 13 hours on stream.

It will be appreciated that there is a significant diifer= ence in conversion and yields produced by the mixed catalyst of this invention, in comparison to that produced lation of degradation products prevented access toalarge by the rate earth-hydrogen exchanged zeoliteX catalyst 17 without a hydrogenation component. Apparently, the regenerative ability exhibited by the mixed catalyst in the presence of hydrogen is due to the efiicient use of the supported platinum metal which is readily available for contact with the hydrogen gas.

EXAMPLE III silicate, platinum metal mixed catalyst for both hydroisomerization and hydrocracking of hydrocarbons having a relatively high molecular weight is further illustrated.

A catalyst identical to that used in Example I for the hydroisomerization of n-hexane was employed to promote the conversion of n-hexadecane, also known as cetane. Cetane and hydrogen were introduced into the top of a tubular reactor containing a fixed bed of the catalyst at 400 p.s.i.g., at a cetane liquid hourly space velocity of 0.25, and at a hydrogen to hydrocarbon molar ratio of 1.2/1. Initially, the temperature of the reactor was raised to 400 F., and a conversion of 42 percent by weight of the charge was obtained.

After three hours at this temperature, the reaction temperature was lowered to 325 F., followed by successive increases to 350, 370, 400, 425 and 450 F. and a drop to 400 F. At this point the input was changed from the top to the bottom of the reactor and the run continued at temperatures of 325, 350, 400 and 425 F. The run was conducted at each of these temperatures over several measured hourly intervals so as to determine the effect of temperature on the conversion of the cetane. As shown by Table 5, only slight aging (a deactivation of catalyst) occurred during the 103 hours on stream and a conversion of over 95 percent by weight of the charge chain.

was obtained at 450 F. In addition, substantially consistent levels of conversion were produced at each temperature. At the lower temperatures the selectivity of the catalyst for hydroisomerization of cetane was high. As the temperature was increased the reaction gradually shifted to form cracked products. The selectivity of the catalyst for producing branched chain isomers as well as branched chain lower molecular weight hydrocarbons, is more fully shown in Tables 6 and 7 which give product analyses of samples taken at 425 F. and 450 F.

Table 8 shows the distribution by carbon number among the cracked products, most of which are isoparaffins with one or more side methyl groups on a normal p-arafiin From n-hexadecane (C 1,) cracked products at 400 F. range from C to C At higher temperatures the higher carbon numbers are gradually converted to the lower range so that at 450 F. the range is essentially C to C In general an n-paraffin charge of X carbon number will yield a range of cracked products from C to C,, and the range can be brought closer to C by more severe conditions of time or temperature. The general cracking pattern with these catalysts may be described as center cracking. This means that each break comes 4 or more carbons from the end of the chain. normal parafiin would initially yield C to C (C to C fragments each largely as isoparaflin. Secondary cracking would remove a second fragment of 4 or more carbons, the C (C yielding C to C (C the 19 (CX-5) Yielding 4 to 15 (CK-9):

A consequence of this mechanism is that it can apply only to n-paraffins of eight or more carbons. Those below C crack much more slowly and tend to accumulate under more severe cracking conditions.

Table 5 Conditions:

Pressure, 400 p.s.i.g. LHSV, 0.25. Hydrogen/Cetane Molar Ratio. 1.2/1.0. Temperature Range, 325-450 F.

[Hydrogen and cetane were fed in top and out bottom of reactor (downfiow) for 1st 71 hours,

then the feed was reversed, in bottom and out top (upflow) for balance of run] Conversion, Wt. Percent Time on Stream, Temperature,

Hours, Total F.

Total Branched Cm Cracked Isomers Products 400 44. 6 16. 1 28. 5 325 4. 8 4. 5 0. 3 325 3. 5 3. 4 0. 1 350 4. 7 4. 5 0. 2 350 4. 4 4. 2 0. 2 350 4. 5 4. 2 0. 3 370 9. 8 7. 3 2. 5 37 0 ll. 7 9. 3 2. 4 370 10.8 8. 5 2.3 370 10. 8 8. 7 2. 1 400 39. 6 11. 2 28. 4 400 41. 3 12. 7 28. 6 400 38. 6 12. 8 25. 8 400 38. 2 11. 5 26. 7 425 73. 3 18. 1 55. 2 425 72. 2 17. 9 54. 3 425 77. 2 9. 5 67. 7 450 99. 2 99. 2 450 98. 9 0. 3 98. 6 450 99. 6 0. 1 99. -5 400 30. 2 10. 4 10. 8 400 33. 5 13. 2 20. 3 400 32. 6 12. G 20. 0 325 2. 7 2. 7 Nil 350 3. 1 3. 1 Nil 350 4. 0 4. 0 Yil 350 3. 5 3. 5 Nil 400 36. 4 16. 0 20. 4 400 36. 6 15. 4 21. 2 425 77. 2 '12. 9 64. 3

Thus a C24 Table 6 PRODUCT ANALYSIS FOR CONVERSION OF CETANE OVER A MIXED CATALYST CONTAINING EQUAL PROPORTI'ONS OF 0.6% WT. PLAT- INUM ON ALUMINA AND A RARE EARTH-HYDROGEN EXCHANGED ZEOLITE X A1 73.3% CONVERSION (48 HOURS) Conditions:

Temperature, 425 F. Pressure, 400 p,s.i.g.

Octane Rate, 0.25 LI-ISV.

Hydrogen/Cetane Ratio (Molar) 1.2/1.

Octane charge stock contains n-hexadecauc (97.50%), probable C11 isomer (0. 18%), n-poutadecane (1.80%), probably 01 isomer (0.08%) and n-tetradccanc (0.23%).

Table 7 PRODUCT ANALYSIS FOR CRACKING OF OETANE OVER 50 50 MIX. OF BAKER 0.0% WT.

Pt-AhO /REHX AT 99.3% CONVERSION (60 HOURS).

S m 7 57 a n11 Q9 2 3 G en mm mm m m m lf .1 8 S m ta w (m Y 2LL2 SP m 1 .1h n3 W mmm w m n C A 0 0 wmmfiw mw% .m o 0 4.1 210 L&0 0 2 1 1 m t pV S/ u t u m n O w n n n 0 0 n m m b a .mm .n n C a. O eet 1 nnn d uu e w bbttU. 3 n nn0 H n n mm m mm nnttml yx nw eeeyycen a tpmn flha u noihtt p u e m eeumd mm w z wmm vi P1. nLnC2 2 2Q uMCn .1 1 1 1 CC C C It is of further interest ing branched chain hydrocarbons, some of which are of lower molecular weight than cetane, is noteworthy in that the great majority of products are usable to provide Table 6 the analysis of the hydrocarbon products produced at 425 F., showed about 7.5 percent by weight of branched chain isomers of cetane, while about 45 percent by weight of the products were other lower 5 molecular weight branched chain parafiinic hydrocarbons. Thus, the greater proportions of the reaction products were branched chain compounds which may be used to upgrade other paraflinic stocks. that no evidence of elofinic or aromatic hydrocarbons will be appreciated that the unique activity of the mixed catalyst of this invention produces a new, highly useful, and convenient process for the hydroisornerization and hydrocracking of parafiinic hydrocarbons.

It will also be appreciated that the examples set forth Table 7-Continued Pt-AI O IREHX AT 99.3% CONVERSION (60 HOURS).

PRODUCT ANALYSIS FOR CRACKING OF CETANE OVER 50/50 MIX OF BAKER 0.6% WT.

This data again shows the continuous conversion of chain hydrocarbons in the st of this invention for an D Aft r1Q3 hours on Stream 60 hydrocarbons having an increased octane rating.

Between these three periods In addition, the selectivity of the catalyst for produc- 75 normal paraffins to branched presence of the mixed cataly extended period of operation.

the catalyst still exhibited substantially all of its unique activity for promoting hydroisomerization and hydrocracking reactions. Moreover, the regenerative ability of the catalyst, that is, its ability to return to a given level of activity and conversion after being placed under less favorable conditions, is again evidenced by the data of Table 5. For instance, the percent conversion by weight obtained at 400 F., was about 39 percent after 39 hours on Stream, 32 Percent after 68 hours, and 36 Percent 70 was found during analysis of the resulting products. after 96 hours on stream.

of operation at 400 F.,'the reaction temperatures had been successively raised to 450 F., and lowered to 325 F., respectively.

above, as well as the foregoing specification, are merely illustrative of the ditferent branched chain paraffinic hydrocarbons which may be isomerized in accordance with the present invention and that other such organic compounds can be hydroisomerized in accordance with the process of this invention.

It Will further be appreciated that the mixed aluminosilicate, platinum metal catalyst, as exemplified by the above rare earth-hydrogen exchanged zeolite X, platinum metal catalyst, may be prepared from other highly acid exchanged alumino-silicates as heretofore described in the specification.

It will additionally be appreciated that the operating conditions for the hydroisomerization and hydrocracking reactions in accordance with the process of this invention, as exemplified in the foregoing examples, may be varied so that the process can be conducted in gaseous phase, liquid phase, or mixed liquid-vapor phase, depending on product distribution, degree of hydroisomerization, and hydrocracking, rate of catalyst deactivation and operating pressures and temperatures, and that various modifications and alterations may be made in the process of this invention without departing from the spirit of the invention.

What is claimed is: V

1. A process for the hydroisomerization of a C C paraffin which comprises effecting isomerization of a C -C paraffin at a temperature from about 400 to 600 F. and at a pressure from about atmospheric to about 600 p.s.i.g. in the presence of hydrogen and in contact with a mixed catalyst consisting essentially of a rare earth-hydrogen exchanged crystalline zeolitic alumino-silicate having a defined pore size of from above about 6 A. to about A. and a hydrogenation component of platinum supported on a thermally stable carrier other than said aluminosilicate, said mixed catalyst containing from about 0.05 to 5.0% 'by weight of platinum and recovering a product mixture containing a major proportion of branched chain isomers of said C 0 paraflln.

2. A process for the hydroisomerization of n-hexane which comprises effecting isomerization of n-hexane at a temperature from about 400 to 600 F. and at a pressure from about atmospheric to about 600 p.s.i.g. in the presence of hydrogen and in contact with a mixed catalyst consisting essentially of a rare earth-hydrogen exchanged crystalline zeolitic alumino-silicate having a defined pore size of from above about 6 A. to about 15 A. and a hydrogenation component of platinum supported on a thermally stable carrier other than said alumino-silicate, said mixed catalyst containing from about 0.05 to 5.0% by weight of platinum and recovering a product mixture containing a major proportion of branched chain isomers of hexane.

3. A process for upgrading of a C paraffin which comprises effecting isomerization of a C parafiin at a temperature from about 300 to about 600 F. in the presence of hydrogen and in contact with a mixed catalyst consisting essentially of a rare earth-hydrogen exchanged crystalline zeolitic alumina-silicate having a defined pore size of from above about 6 A. to about 15 A. and a hydrogenation component of platinum supported on a thermally stable carrier other than said alumino-silicate, said mixed catalyst containing from about 0.05 to 5.0% by weight of platinum and recovering a product mixture containing a major proportion of branched chain isomers of said C paraffin when the reaction temperature is below about 400 F. and a min-or proportion of said isomers when the reaction temperature is at 400 F. and above.

4. A process for upgrading of cetane which comprises effecting isomerization of cetane at a temperature from about 300 to about 600 F. in the presence of hydrogen and in contact with a mixed catalyst consisting essentially of a rare earth-hydrogen exchanged crystalline zeolitic alumino-silicate having a defined pore size of from above about 6 A. to about 15 A. and a hydrogenation component of platinum supported on a thermally stable carrier other than said aluminosilicate, said mixed catalyst containing from about 0.05 to 5.0% by weight of platinum and recovering a product mixture containing a major proportion of branched chain isomers of said cetane when the reaction temperature is below about 400 F. and a minor proportion of said isomers when the reaction temperature is at 400 F. and above.

5. A process for the hydroisomerization of a C -C paraffin which comprises effecting isomerization of a C C parafiin at a temperature from about 400 to 600 F. and at a pressure from about atmospheric to about 600 p.s.i.g. in the presence of hydrogen and in contact with a mixed catalyst consisting essentially of a rare earth-hydrogen exchanged zeolite X and a hydrogenation component of platinum supported on an alumina carrier, said mixed catalyst containing from about 0.05 to 5.0 percent by weight of platinum, and recovering a product mixture containing a major proportion of branchedchain isomers of said C C paraifin.

6. The process of claim 5 in which the mixed catalyst is an intimate mixture of equal proportions by weight of the rare earth-hydrogen exchanged zeolite X and a hydrogenation component containing 0.6 percent by weight platinum supported on alumina.

7. A process for hydr-oisomerization of n-hexane which comprises effecting isomerization of n-hexane at a temperature from about 400 to 600 F. and at a pressure from about atmospheric to about 600 p.s.i.g. in the presence of hydrogen and in contact with a mixed catalyst consisting essentially of a rare earth-hydrogen exchanged zeolite X and a hydrogenation component of platinum supported on an alumina carrier, said mixed catalyst containing from about 0.05 to 5.0 percent by weight of platinum, and recovering a product mixture containing a major proportion of branched chain isomers of hexane.

8. The process of claim 7 in which the mixed catalyst is an intimate mixture of equal proportions by Weight of the rare earth-hydrogen exchanged zeolite X and a hydrogenation component containing 0.6 percent by weight platinum supported on alumina. H

9. A process for upgrading of a C parafiin which comprises effecting isomerization with a C paraffin at a temperature from about 300 to about 600 F. in the presence of hydrogen and in contact with a mixed catalyst consisting essentially of a rare earth-hydrogen exchanged zeolite X and a hydrogenation component of platinum supported on an alumina carrier, said mixed catalyst containing from about 0.05 to 5.0 percent by weight of platinum and recovering a product mixture containing a major proportion of branched chain isomers of said 0 parafiin when the reaction temperature is below about 400 F. and a minor proportion of said isomers when the reaction temperature is at 400 F. and above.

10. The process of claim 9 in which the mixed catalyst is an intimate mixture of equal proportions by weight of a rare earth-hydrogen exchanged zeolite X and a hydrogenation component containing 0.6 percent by weight platinum supported on alumina.

11. A process for upgrading of cetane which comprises effecting isomerization of cetane at a temperature from about 300 to about 600 F. in the presence of hydrogen and in contact with a mixed catalyst consisting essentially of a rare earth-hydrogen exchanged zeolite X and a hydrogenation component of platinum supported on an alumina carrier, said mixed catalyst containing from about 0.05 to 5.0 percent by weight of platinum and recovering a product mixture containing a major proportion of branched chain isomers of cetane when the reaction temperature is below about 400 F. and a minor proportion of said isomers when the reaction temperature is at 400 F. and above.

12. The process of claim 11 in which the mixed catalyst is an intimate mixture of equal proportions by weight of a rare earth-hydrogen exchanged zeolite X and a hydrogena- References Cited by the Examiner UNITED STATES PATENTS 2/1961 Ki mberlin et a1. 208-46 5/1962 Frilette 208-46 Eng 208-46 Plank et a1. 260683.65 Gallagher 2'60683.65

Benesi 260683.65

DELBERT E. GANTZ, Primary Examiner.

R. H. SHUBERT, Assistant Examiner.

Claims (1)

1. 3. A PROCESS FOR UPGRADING OF A C9+ PARAFFIN WHICH COMPRISES EFFECTING ISOMERIZATION OF A C9+ PARAFFIN AT A TEMPERATURE FROM ABOUT 300* TO ABOUT 600*F. IN THE PRESENCE OF HYDROGEN AND IN CONTACT WITH A MIXED CATALYST CONSISTING ESSENTIALLY OF A RARE EARTH-HYDROGEN EXCHANGED CRYSTALLINE ZEOLITIC ALUMINO-SILICATE HAVING A DEFINED PORE SIZE OF FROM ABOVE ABOUT 6 A. TO ABOUT 15 A. AND A HYDROGENATION COMPONENET OF PLATINUM SUPPORTED ON A THERMALLY STABLE CARRIER OTHER THAN SAID ALUMINO-SILICATE, SAID MIXED CATALYST CONTAINING FROM ABOUT 0.05 TO 5.0% BY WEIGHT OF PLATINUM AND RECOVERING A PRODUCT MIXTURE CONTAINING A MAJOR PROPORTION OF BRANCHED CHAIN ISOMERS OF SAID C9+ PARAFFIN WHEN THE REACTION TEMPERATURE IS BELOW ABOUT 400*F. AND A MINOR PROPORTION OF SAID ISOMERS WHEN THE REACTION TEMPERATURE IS AT 400*F. AND ABOVE.