US3223617A

US3223617A - Catalytic hydrocarbon conversion

Info

Publication number: US3223617A
Application number: US169934A
Authority: US
Inventors: Maziuk John
Original assignee: Socony Mobil Oil Co Inc
Current assignee: ExxonMobil Oil Corp
Priority date: 1962-01-30
Filing date: 1962-01-30
Publication date: 1965-12-14
Anticipated expiration: 1982-12-14
Also published as: GB1031222A; DE1442850A1

Description

United States Patent C) 3,223,617 CATALYTIC HYDROCARBON CONVERSION John Maziuk, West Deptford Township, Gloucester County, N.J., assignor to Socony Mobil Oil Company, Inc., a corporation of New York No Drawing. Filed Jan. 30, 1962, Ser. No. 169,934 Claims. (Cl. 208138) This invention relates to catalytic hydrocarbon conversion and to the catalyst employed therein. More particularly, the present invention is directed to a process for effecting rearrangement of hydrocarbon molecules in the presence of hydrogen and a unique catalyst composition. Exemplary of the hydrocarbon conversion reaction with which this invention is concerned are dehydrogenation, hydrogenation, isomerization, aromatization, cyclization, dealkylation, alkylation, dehydroisomerization, polymerization and combinations of such reactions such as for example in reforming where a multitude of reactions take place including isomerization, cyclization, aromatization, dehydrogenation, etc. to yield a product having an increased content of aromatics and highly branched parafiins.

Such reforming operations, wherein hydrocarbon fractions such as naphthas, gasolines and kerosene are treated to improve the anti-knock characteristics thereof are well known in the petroleum industry. These fractions are composed predominately of normal and slightly branched paraffinic hydrocarbons and naphthenic hydrocarbons together with small amounts of aromatic hydrocarbons. During reforming, it is desired to dehydrogenate the naphthenic hydrocarbons to produce aromatics, to cyclize the straight chain parafiinic hydrocarbons to form aromatics, to isomerize the normal and slightly branched paraflins to yield highly branched chain paraffins and to effect a controlled type of cracking which is selective both in quality and quantity.

Normal and slightly branched chain paraflinic hydrocarbons of the type contained in the above fractions have relatively low octane ratings. Highly branchedchain paraffinic hydrocarbons, on the other hand, are characterized by high octane ratings. Accordingly, one objective of reforming is to effect isomerization of the normal and slightly branched-chain parafiins to more highly branched-chain paraffins. Since aromatic hydrocarbons have much higher octane ratings than naphthenic hydrocarbons, it is also an objective of reforming to simultaneously produce aromatics in good yield. The production of aromatic hydrocarbons during reforming is effected by dehydrogenation of the naphthenic hydrocarbons and dehydrocyclization of the paraflinic hydrocarbons. Aromatic hydrocarbons are also produced by isomerization of alkyl cyclopentanes to cyclohexanes which thereafter undergo dehydrogenation to form the desired aromatics.

Controlled or selective cracking is highly desirable during reforming since such will result in a product of improved anti-knock characteristics. As a general rule, the lower molecular weight hydrocarbons exhibit a higher octane number, and a gasoline product of lower average molecular weight will usually have a higher octane number. The splitting or cracking of carbon to carbon linkages must, however, be selective and should be such as not to result in substantial decomposition of normally liquid hydrocarbons to normally gaseous hydrocarbons. The selective cracking desired ordinarily involves removal of one or more lower alkyl groups such as methyl, or ethyl from a given molecule in the form of methane or ethane. Thus, during reforming, it is contemplated that heptane may be converted to hexane, nonane to octane or heptane, etc. Uncontrolled cracking, on the other band, would result in decomposition of normally liquid hydrocarbons into normally gaseous hydrocarbons. For example, non-selective cracking of normal octane would ultimately lead to eight molecules of methane. Since methane, ethane and propane cannot be used in gasoline they constitute a loss in the process and the production of excessive amounts of these lower parafiins accordingly is to be avoided. Butanes, on the other hand, tend to increase the octane rating of gasoline but the effective amount of butane present in the finished gasoline is limited by the maximum permissible vapor pressure.

Uncontrolled cracking, moreover, generally results in rapid formation and deposition on the catalyst of large quantities of a carbonaceous material generally referred to as coke. The production of coke not only results in decreased yields of gasoline but the deposition thereof on the catalyst surface diminishes or destroys its catalyzing effect and results in shorter processing periods with the accompanying necessity of frequent regeneration by burning the coke therefrom. In those instances where the activity of the catalyst is destroyed, it is necessary to shut down the unit, remove the deactivated catalyst and replace it with new catalyst.

When reforming is carried out in the presence of hydrogen, under pressure, the formation of coke is to some extent inhibited. Accordingly, it has been general practice to effect reforming in the presence of hydrogen and such processes have sometimes been referred to as hydroforming. An increase in hydrogen pressure during reforming results in inceasing the temperature at which aromatization, including dehydrogenation and dehydrocyclization occurs. The isomerization reactions taking place, on the other hand, are independent of pressure. Reforming in the presence of a catalyst which provides maximum isomerization at relatively low temperatures is disadvantageous in operations wherein pressure conditions have elevated the temperature range of the aromatization reaction. To achieve maximum conversion to high octane gasoline, maximum isomerization should occur at temperatures sufficiently high to effect good conversion to aromatic hydrocarbons.

Accordingly, the choice of catalyst for promoting reforming of hydrocarbons to gasolines of enhanced octane rating is dependent on several factors. Such catalyst should desirably be capable of effecting reforming in a controlled and selective manner as discussed above to yield a product of improved anti-knock characteristics. The catalyst selected should, further be resistant to poisoning and should also desirably be characterized by high stability and be capable of easy regeneration.

Likewise, the catalyst employed in hydrocarbon dehydrogenation, .isomerization, cyclization, dehydroisomerization and other of the reactions specified hereinabove should desirably possess high selectivity, i.e. the ability to afford a high yield of useful conversion products with a low accompanying yield of undesired products, such as coke and light hydrocarbons.

It has heretofore been known to carry out hydrocarbon conversion openations involving reactions of the type indicated hereinab-ove in the presence of a catalytic composite of two or more chemically combined components to control the direction and extent of desired conversion. Thus, in hydrocarbon conversion reactions such as isomerization, aromatization, reforming, dehydrogenation, hydrogenation, etc. wherein a hydrocarbon charge is contacted in the presence of hydrogen with a catalyst under conversion conditions of time, temperature and pressure, it has heretofore been common practice to employ a catalyst comprising a component having cracking activity impregnated or otherwise chemically combined with a component having dehydrogenation activity. Illustrative of the catalysts which have been used in such reactions are composites of silica and/or alumina combined with small quantities of platinum. In some instances, the silica and/or alumina component has been previously treated with a small amount of halogen and thereafter combined with platinum. Such catalysts, while generally exhibiting the desired activity are subject to improvement, particularly with regard to selectivity.

It is an object of the present invention to afford a process for carrying out the aforementioned hydrocarbon conversion reactions in the presence of a catalyst characterized by unusual selectivity. It is a further object of this invention to provide an improved hydrocarbon conversion catalyst. A still further object of this invention is to provide an improvement in catalytic reforming of petroleum hydrocarbon mixtures. Other objects include an improved catalytic dehydrogenation process and an improved catalytic dehydroisomerization process.

The foregoing and other objects which will be apparent to those skilled in the art are achieved by means of the catalyst and process described herein. In accordance with the present invention, it has been discovered that hydrocarbon conversion in the presence of hydrogen can be selectively effected in the presence of a catalyst consisting essentially of a mechanical mixture of particles of less than about 100 microns in diameter of: (1) an alumina-containing carrier having deposited thereon an amount of platinum metal such that the ultimate catalyst has a platinum metal content of between about 0.05 and about percent by weight and (2) a rare earth metal oxide deposited on a porous inert carrier in an amount such that the ultimate catalyst has a rare earth metal oxide content of between about 0.1 and about 40 percent by weight.

In one embodiment, the instant invention provides an improved hydrocarbon conversion catalyst consisting essentially of a mechanical mixture of particles of less than about 100 microns in diameter of (1) a carrier comprising predominately alumina having deposited thereon an amount of a metal of the platinum series such that the ultimate catalyst has a content of said metal between about 0.05 and about 5 percent by weight and (2) a porous inert carrier having deposited thereon an amount of an oxide of a rare earth metal such that the ultimate catalyst has a rare earth metal oxide content of between about 0.1 and about 40 percent by weight, the relative weight fractions of the two components being between about 0.1 and about 0.9. In another embodiment, the invention provides an improved process for reforming hydrocarbon mixtures in the presence of the aforementioned catalyst. In still another embodiment, the invention atfords an improved hydrocarbon dehydrogenation process carried out in the presence of the above-described catalyst. In a still further embodiment, the invention provides an improved process for dehydroisomerization of hydrocarbons in the presence of the specified catalyst.

The rare earth metal oxide component of the present catalyst may comprise for example, cerium, lanthanum, praseodymium, neodymium, samarium, ytterbium, gadolinium or mixtures of oxides of the e metal as well as yttrium oxide and mixtures thereof with the foregoing metal oxides. The base material employed to support the rare earth metal oxide component may be any porous high surface area material capable of operating under the required conditions of reaction and handling and which is chemically inert under the contemplated conditions, i.e. a material which, when brought at reaction conditions with the charge undergoing conversion would effect substantially no change therein due to its presence. The available surface area of the supporting material should generally be in excess of 10 square meters per gram. Typical of the supporting materials for the rare earth metal oxide component are s1lica gel, alumina, other oxide gels, natural clays, bauxite, pumice stone, kaolin, charcoal, kieselguhr, porous glass, magnesia, asbestos, coke, magnesium sulfate, etc. The rare earth metal oxide may be deposited on the carrier in any suitable manner. One feasible method is to admix particles of the carrier with an aqueous solution of suitable concentration of a water-soluble compound of the rare earth metal, such as the chloride, sulfate or nitrate of the rare earth metal or metals, the oxide of which is to be deposited on the supporting material. The impregnated particles are thereafter dried in air at an elevated temperature. The concentration and quantity of the impregnating solution employed is such that the deposition of rare earth metal oxide in the ultimate catalyst is generally between about 0.1 and about 40 and more particularly between about 3 and about 15 weight percent.

The platinum metal component of the present catalyst may comprise platinum, palladium, rhodium, osmium, iridium, or ruthenium, as well as alloys or mixtures of these metals. Of the foregoing, platinum and palladium and in particular platinum, are accorded preference. The amount of the platinum metal contained in the instant catalyst is generally between about 0.05 and about 5 weight percent and more usually between about 0.1 and about 2 weight percent. The platinum metal component is deposited on a carrier comprising predominately alumina. The carrier may also contain combined halogen such as, for example, fluorine, chlorine, etc. The halogen content of such carrier may be from about 0.01 to about 10 percent by weight and preferably about 0.2 to about 8 percent by weight. Another effective carrier comprises alumina having incorporated therein a small amount of silica, namely, in the amount of 0.1 to about 10 percent by weight, which serves to enhance the stability of the platinum metal component at elevated temperatures. An excellent carrier for the platinum metal component of the present catalyst is alumina. The alumina carrier may be in the form of a precipitate or gel. Various forms of alumina either singly or in combination, such as eta, chi, gamma, theta, delta or alpha alumina may be suitably employed as the alumina carrier. The above nomenclature with reference to alumina phase designation is that described in The Aluminum Industry: Aluminum and Its Production, by Edwards, Frary and Jeffries, published by McGraw-Hill (1930). The alumina carrier preferably is in the form of eta or gamma alumina or mixtures of the two. Such alumina carrier can be prepared by a variety of methods, such as by reaction of aluminum, water and an acid with mercury or mercuric oxide under suitable conditions to produce a hydrous or hydrated alumina or alumina sol, which upon subsequent treatment with an alkaline reagent undergoes gelation. The alumina may also be prepared by reacting aluminum, water and mercury or mercuric oxide at an elevated temperature. Another method is to precipitate alumina by treating an aluminum salt with an alkaline reagent, such as ammonium hydroxide, after which the alumina is aged over an extended period of time, for example 10 hours or longer.

The platinum metal may be deposited on the carrier in any suitable manner. One feasible method is to admix particles of the carrier with an aqueous solution of an acid of the metal, for example, chloroplatinic acid or chloropallidic acid or of the ammonium salt of the acid of suitable concentration. The impregnated particles are then dried and treated with hydrogen at an elevated temperature to reduce the chloride to the metal and to activate the platinum metal-containing component.

In accordance with the present invention, the weight fractions of inert carrier supporting the rare earth metal oxide component and the platinum metal component deposited on a carrier comprising predominately alumina may vary widely, thereby affording desirable flexibility in the catalyst composition, which may be varied with the specific charge stock undergoing treatment and with the particular reaction conditions under which the conversion operation is effected. In general, however, the relative weight fraction of the two components is between about 0.1 and about 0.9.

The average particle size of each of the components making up the present catalyst should be less than about 100 mesh. Excellent results have been obtained with a catalyst having a particle size in the range of about 100 to about 400 mesh (Tyler). It is accordingly contemplated that catalyst of this invention will, in general, comprise particles having a diameter below 100 microns, and, particularly, a diameter in the range of l to 100 microns.

The particle size of the two components may, within the foregoing range, be substantially identical or may vary widely. For affording a means of ready separation of the catalyst components, it is often desirable to employ a mixture wherein the rare earth metal oxide and platinum metal components have slightly different particle size.

The catalyst of this invention may be used in the form of discrete particles in the fluidized state having the aforesaid requisite diameter, or the components having such particle size may be admixed and pelleted, cast, molded, or otherwise formed into pieces of desired size and shape, such as rods, spheres, pellets, etc. it being essential, however, for optimum results that each of said pieces is composed of particles of both components having a particle diameter of less than about 100 microns. In the latter case, the mixture, if and when desired, may be separated into its components by initially crushing to a particle size comparable to or below the magnitude of the small constituent particles and thereafter separating the component particles by flotation, air-blowing, sifting or by any of various other known means for separating physically and/or chemically different materials. The separated components may then be separately regenerated or platinum metal may be readily recovered from the component containing the same.

The catalyst of this invention accordingly affords complete and immediate flexibility in catalyst composition within the limits set forth hereinabove. Thus, in changing types of charge stocks, a catalyst composition can be adjusted immediately in accordance with this invention by adding or withdrawing one or the other catalyst component. The present catalyst further affords considerable flexibility in the nature of the product obtained. As will be appreciated, the ability to adjust catalyst composition, together with the flexibility in the nature of desired product upon change in temperature is highly advantageous in a hydrocarbon conversion operation.

The process of this invention may be carried out in any equipment suitable for catalytic operations. The process may be operated batchwise. It is preferable, however, and generally more feasible to operate continuously. Accordingly, the process is adapted to operations using a fixed bed of catalyst. Also, the process can be operated using a moving bed of catalyst wherein the hydrocarbon flow may be concurrent or countercurrent to the catalyst flow. A fluid type of operation wherein the catalyst is carried in suspension in the hydrocarbon charge is well adapted for use with the instant catalyst since pelleting or otherwise shaping of the catalyst components is thus rendered unnecessary.

The conditions under which hydrocarbon conversion in the presence of hydrogen is effected with the present catalyst are those conventionally employed for the particular desired reaction. Generally, taking into consideration the charge stock and the extent and direction of desired reaction, conversion is carried out at a temperature between about 500 F. and about 1200 F. The hydrogen pressure employed is between about atmospheric and abount 5000 pounds per square inch. The liquid hourly space velocity, i.e. the liquid volume of hydrocarbon per hour per volume of catalyst is between about 0.1 and about 10. Generally, the molar ratio of hydrogen to hydrocarbon charge is between about 0.5 and about 80. Within the aforementioned ranges, it will be appreciated that there are preferred conversion conditions for a particular operation. Thus, for reforming, the temperature is ordinarily between about 700 F. and about 1000 F. and, preferably between about 725 F. and about 975 F. The hydrogen pressure in reforming is ordinarily between about and about 1000 pounds per square inch gauge and, preferably, between about 200 and about 700 pounds per square inch gauge. The liquid hourly space velocity for reforming is preferably between about 0.5 and about 4 and the ratio of hydrogen to hydrocarbon charge is generally between about 0.5 and about 20, preferably between about 4 and about 12. For dehydrogenation, the temperature is ordinarily between about 900 F. and about 1200 F. and preferably between about 950 F. and about 0 F. The hydrogen pressure in such operation is ordinarily between about 5 and about 100 pounds per square inch gauge and, preferably, between about 15 and about 30 pounds per square inch gauge. The liquid hourly space velocity for dehydrogenation is preferably between about 0.5 and about 3.0 and the ratio of hydrogen to hydrocarbon charge is generally between about 0.5 and about 10 and, preferably, between about 1 and about 4. For dehydroisomerization, the temperature of reaction is generally within the approximate range of 800 to 980 F. The hydrogen pressure in such reaction is ordinarily between about 100 and about 500 pounds per square inch gauge and the liquid hourly space velocity generally between about 0.1 and about 10. The ratio of hydrogen to hydrocarbon charge in the dehydroisomerization reaction is generally between about I and about 10.

The charge stock undergoing conversion in accordance with the present process may be a normally liquid hydrocarbon or mixture consisting predominantly of such bydrocarbons. Thus, the hydrocarbon charge stocks treated in accordance with the invention may suitably comprise petroleum fractions including reforming feed stocks of petroleum distillates boiling within the range of 60 F. to 450 E, which range includes naphthenes, gasoline and kerosene. For dehydrogenation, a wide variety of organic compounds may be employed, including naphthenes, paraffins, butenes, etc. For dehydroisomerization, naphthenes, paraifins, indanes, and tetralins may be employed.

It is well known that platinum-containing reforming catalysts lose activity gradually upon use as a result of regeneration with air. The treatment wtih air at an elevated temperature is believed to adversely affect the platinum. In one embodiment of the present invention, a mixture of platinum-containing and rare earth metal oxidecontaining particles is employed in hydrocarbon conversion. The spent catalyst mixture is thereafter separated into its components by providing the same with a suitable different physical characteristic which permits their ready separation, such as difference in particle size. Thereafter, the catalyst components may be separately regenerated by subjecting the rare earth metal oxide component to regeneration with air. The treatment with air at an elea sufficient time and at a sufficiently elevated temperature to burn carbonaceous material therefrom but under conditions such that sintering of the rare earth metal oxide component is not encountered. Generally, these conditions are fulfilled by regenerating in air for a period in the range of about 10 minutes to about 1 hour and a temperature in the approximate range of 1000 F. to 1400 F. The separated platinum metal-containing component is subjected to regeneration treatment with hydrogen for a period in the range of 1 to hours at a temperature in the range of 900 F. to 1100 F. After separate regeneration, the components are again mixed and recycled to the reaction zone. Such process may be carried out batch-wise or continuously.

In accordance with the present invention, it has been discovered that the above described mechanical mixture of particles of less than about 100 microns in diameter of 1 (l) a carrier comprising predominantly alumina having deposited thereon a specified amount of platinum metal and (2) a porous inert carrier having deposited thereon a specified amount of rare earth metal oxide olfords an unusual hydrocarbon conversion catalyst possessing exceptional selectivity in conversion reactions effected in the presence of hydrogen, such as reforming, dehydrogenation, dehydroisomerization, etc.

It has been particularly found that the catalyst described herein alfords an increased yield of desired conversion products, lower coke make and increased hydrogen production over a catalyst comprising platinum metal deposited on an alumina carrier in the absence of the specified rare earth metal oxide component.

The following comparative examples will serve to illustrate the catalyst and process of this invention without limiting the same:

Example 1 A mechanically mixed catalyst comprising an equal weight mixture of particles of 0.6 weight percent platinum deposited on alumina (component A) and particles of 15 percent by weight samaria deposited on alumina (component B) was prepared as follows:

Component A, a commercially available catalytic composite containing about 0.6 weight percent platinum and about 0.6 weight percent chlorine deposited on an alumina carrier consisting substantially of eta alumina together with a minor proportion of gamma alumina, was crushed and ball milled to a particle size of approximately 5 microns in diameter.

Component B was prepared in the following manner:

To 4448 grams NaOH dissolved in 13.0 pounds of steam condensate, there was added 8340 grams To this solution, a solution containing 200 grams Sm O 1400 grams water, and 8.62 pounds of 69.8 percent HNO was added. The resulting solution was agitated for 2 hours and thereafter filtered and washed with water until free of nitrate. The washed product was dried for 16 hours at 240 F., ground to a particle size of less than 60 mesh and then calcined in nitrogen at a maximum temperature of 925 F. The resulting composite was crushed and ball milled to a particle size of approximately 5 microns in diameter.

The finely divided particles of platinum on alumina and samaria on alumina was then thoroughly mixed on an equal weight basis and pelleted. The resulting pellets were calcined in a mixture of 98 percent nitrogen and 2 percent air at a temperature of about 850 F. to yield the finished catalyst.

Example 2 The catalyst of Example 1, as well as the platinum metal component alone, were employed in dehydrogenation of cyclohexane. Such process was carried out in the presence of hydrogen at a temperature of 920 F., a pressure of 200 p.s.i.g., utilizing a liquid hourly space velocity of 2 and a hydrogen to hydrocarbon mol ratio of 4. The

products obtained in each instance were analyzed and the analysis is shown below:

0.6% Pt on Catalyst 0.6% Pt on alumina alumina 15% samaria on alumina Yields, percent wt. of charge:

Hz 6. 4O 6. 69

0.30 0 0. 45 0.14 0. 57 0 0. 61 0 0.97 0 06+ 90.70 93.17 0 Distribution Moles naphthcnes/lOO moles of charge going to:

Benzene 88. 0 88. 4 O5 parafllns, olcfins, and cracked products 10. 7 1. 9

Total 98. 7 90. 3 Unconverted. 1. 3 9. 7 Naphthene conversion 98. 7 90. 3 Selectivity: Moles benzeneXlOO/molcs naphthenes converted 89. 2 97. 9

The above data show the very substantial improvement of the catalyst of the invention over the platinum-containing catalyst alone. Thus, with the present catalyst, there was a complete absence of dry gas and C and C materi als. The almost perfect selectivity for conversion, i.e. 97.9%, illustrates the highly unusual and effective nature of the described mechanically mixed catalyst.

Example 3 The catalyst of Example 1, the platinum metal component alone, and a 1/1 mixture of the platinum component with alumina free of rare earth oxide were employed in the dehydroisomerization of methylcyclopentane. Such process was carried out in the presence of hydrogenat a temperature of 940 F., a pressure of 200 p.s.i.g., utilizing a liquid hourly space velocity of 2 and a hydrogen to hydrocarbon mole ratio of 4-5. The products obtained in each instance were analyzed and the analysis is shown below:

0.6% Pt on 0.6% Pt on 0.6% Pt on alumina+ Catalyst alumina almnina+ 15% alumina samaria on alumina Yields. percent wt of charge:

3. 37 1. 88 2. 50 0.90 0.23 0. 19 1. 13 0. 40 0. l9 1. 37 0. 58 0.13 1.80 0.86 0.07 2. l2 0. 46 0.07 o0 89.31 95. 59 96.85 00+ d1str1but1on Moles naphthenes/lOO moles of charge going to:

Benzene 64. 9 33. 4 49. 6 O5 paraflins and cracked products 32. 1 23.2 22. 2 Miscellaneous 0.7 1. 3 2. 4 Total converted. 97. 7 57. 9 74. 2 Unconverted 2. 3 42. 1 25. 8 Conversion 97. 7 57. 9 74. 2 Selectivity: Moles benzeneXlOU/ moles naphthene eonverted 66. 4 57. 7 66. 8 Estimated at same conversion level (74%): Moles benzene/ moles naphthene converted 63.2 59.0 67.0

The foregoing data again show the very substantial improvement in selectivity of the present catalyst over platinum-containing catalyst alone and platinum-containing catalyst plus alumina. Particularly noteworthy is the low extensive cracking tendencies of the catalyst of this invention as evidenced by its lower weight yields of C and lighter hydrocarbons.

Example 4 The catalyst of Example 1, as well as the platinum metal component alone, were employed in reforming of a Mid-Continent naphtha having a boiling range of C 250 F. Reforming was carried out at a pressure of 200 p.s.i.g. utilizing a liquid hourly space velocity of 0.8 and a hydrogen to hydrocarbon mol ratio of 7. The reformate products obtained in each instance having an octane number of 110 (Research-i-B cc. TEL) were analyzed and the analysis is shown below:

It will be evident from the results achieved in Example 4 that the catalyst described herein shows a yield improvement when used in reforming over the platinum-containing catalyst alone.

The following example will serve to show that samaria on alumina alone used as a catalyst was ineffective for reforming.

Example 5 A charge stock consisting of a 200 F. end point Mid- Continent naphtha was contacted under reforming conditions with a catalyst comprising 15 weight percent samaria deposited on alumina. The conditions of contact involved a temperature of 960 F., a pressure of 15 p.s.i.g., a liquid hourly space velocity of 2 and a hydrogen to hydrocarbon mol ratio of 3. The reformate product showed an octane number (CFRR octane, clear) of 67.0 while the charge stock possessed an octane number (CFRR octane, clear) of 68.9. Thus, the octane number of the product was actually lower than that of the charge stock.

The following example will serve to show that platinum impregnated on an alumina-samaria composite does not afford the improved selectivity characteristics of the present mechanically mixed catalyst and is, in fact, not as selective as platinum deposited on alumina alone.

Example 6 A C 250 F. Mid-Continent naphtha charge stock was contacted with a catalyst consisting essentially of alumina impregnated with about 15 weight percent samaria having deposited thereon about 0.6 weight percent of platinum and in a separate run with a catalyst consisting essentially of alumina impregnated with about 0.6 weight percent of platinum. The conditions of contact, in each instance, included a pressure of 200 p.s.i.g., a hydrogen to hydrocarbon mol ratio of 7 and a liquid hourly space velocity of 1 with the temperature being varied to give 95 octane number. The reformate products obtained in each instance having an octane number of 95 (Research+3 cc. TEL) were analyzed and the analysis is shown below:

The following example will serve to show that ceria on alumina, as well as samaria on alumina, in combination 10 with platinum-containing catalyst produces an effective reforming catalyst.

Example 7 The catalyst of Example 1, as well as a 0.6% Pt on alumina+15% ceria on alumina catalyst were employed in reforming a Mid-Continent naphtha having a boiling range of 180 to 380 F. Reforming was carried out at a pressure of 200 p.s.i.g. utilizing a liquid hourly space velocity of 1.0 and a hydrogen to hydrocarbon mole ratio of 7. An analysis of the reformate products having an octane of 98.7 (Research-i-B cc. TEL) is shown below:

0.6% Pt on alumina+ 15% ceria on alumina Catalyst Yields of charge:

Crly v01. 85. 3 86. 5 Gasoline (10 RVP), vol 98.0 98.4 Hz, s.c.f./bbl. ehg 1, 97.0 Hz in recycle, mol percent. 86. 0 87.7

It is accordingly to be understood that the above description is merely illustrative of preferred embodiments of the invention of which many variations may be made within the scope of the following claims by those skilled in the art without departing from the spirit thereof.

I claim:

1. A hydrocarbon conversion catalyst consisting essentially of :a mechanical mixture of particles of less than about 100 microns in diameter of: (1) particles consisting of a carrier comprising predominately alumina having deposited thereon an amount of platinum such that the ultimate catalyst has a platinum content of between about 0.05 and about 5 percent by weight and (2) particles consisting of a porous inert carrier having deposited thereon an amount of samaria such that the ultimate catalyst has a samaria content of between about 0.1 and about 40 percent by weight, the relative weight fractions of the two components being between about 0.1 and about 0.9.

2. A hydrocarbon conversion catalyst consisting essentially of a mechanical mixture of particles of less than about 100 microns in diameter of: (1) particles consisting of a carrier comprising predominately alumina having deposited thereon an amount of platinum such that the ultimate catalyst has a platinum content of between about 0.5 and about 5 percent by weight and (2) particles consisting of a porous inert carrier having deposited thereon an amount of ceria such that the ultimate catalyst has a ceria content of between about 0.1 and about 40 percent by weight, the relative weight fractions of the two components being between about 0.1 and about 0.9.

3. A hydrocarbon conversion catalyst consisting essentially of a mechanical mixture of substantially equal parts by weight of particles of less than about 100 microns in diameter of: (1) particles consisting of a carrier comprising predominately alumina having deposited thereon an amount of a metal of the platinum series such that the ultimate catalyst has a content of said metal beween about 0.05 and about 5 percent by weight and (2) particles consisting of a porous inert carrier having deposited thereon an amount of an oxide of a rare earth metal selected from the group consisting of ceria and samaria such that the ultimate catalyst has a rare earth metal oxide content of between about 0.1 and about 40 percent by Weight.

4. A process for reforming a hydrocarbon mixture which comprises contacting said mixture under reforming conditions in the presence of hydrogen with a catalyst consisting essentially of a mechanical mixture of particles of less than about 100 microns in diameter of: (1) particles consisting of a carrier comprising predominately alumina having deposited thereon an amount of a metal of the platinum series such that the ultimate catalyst has a content of said metal between about 0.05 and about percent by weight, and (2) particles consisting of a porous inert carrier having deposited thereon an amount of an oxide of a rare earth metal selected from the group consisting of ceria and samaria such that the ultimate catalyst has a rare earth metal oxide content of between about 0.1 and about 40 percent by weight, the relative weight fractions of the two components being between about 0.1 and 0.9.

5. A process for dehydrogenation of a dehydrogenatable hydrocarbon which comprises contacting said hydrocarbon with hydrogen under dehydrogenation conditions in the presence of a catalyst consisting essentially of .a mechanical mixture of particles of less than about 100 microns in diameter of: (1) particles consisting of a carrier comprising predominately alumina having deposited thereon an amount of a metal of the platinum series such that the ultimate catalyst has a content of said metal between about 0.05 and about 5 percent by weight and; (2) particles consisting of a porous inert carrier having deposited thereon an amount of an oxide of a rare earth metal selected from the group consisting of ceria and samaria such that the ultimate catalyst has a rare earth metal oxide content of between about 0.1 and about 40 percent of weight, the relative weight fractions of the two components being between about 0.1 and about 0.9.

6. A process for dehydroisomerization of a dehydroisomerizable hydrocarbon which comprises contacting said hydrocarbon under dehydroisomerization conditions in the presence of hydrogen with a catalyst consisting essentially of a mechanical mixture of particles of less than about 100 microns in diameter of: (1) particles consisting of a carrier comprising predominately alumina having deposited thereon an amount of a metal of the platinum series such that the ultimate catalyst has a content of said metal between about 0.05 and about 5 percent by weight and; (2) particles consisting of a porous inert carrier having deposited thereon an amount of an oxide of a rare earth metal selected from the group consisting of ceria and samaria such that the ultimate catalyst has a rare earth metal oxide content of between about 0.1 and about 40 percent by weight, the relative weight fractions of the two components being between about 0.1 and about 0.9.

7. A process for converting hydrocarbons in the presence of hydrogen which comprises contacting the hydrocarbon charge under conversion conditions with a catalyst consisting essentially of a mechanical mixture of particles of less than about 100 microns in diameter of: (1) particles consisting of a carrier comprising predominately alumina having deposited thereon an amount of,

platinum such that the ultimate catalyst has a platinum content of between about 0.05 and about 5 percent by weight and (2) particles consisting ofa porous inert carrier having deposited thereon an amount of samaria such that the ultimate catalyst has a samaria content of between about 0.1 and about 40 percent by weight, the relative weight fractions of the two components being between about 0.1 and about 0.9.

8. A process for converting hydrocarbons in the presence of hydrogen which comprises contacting the hydrocarbon charge under conversion conditions with a catalyst consisting essentially of a mechanical mixture of particles of less than about microns in diameter of: (1) particles consisting of a carrier comprising predominately alurnina having deposited thereon an amount of platinum such that the ultimate catalyst has a platinum content of between about 0.05 and about 5 percent by weight and (2) particles consisting of a porous inert carrier having deposited thereon an amount of ceria such that the ultimate catalyst has a ceria content of between about 0.1 and about 40 percent by weight, the relative weight fractions of the two components being between about 0.1 and about 0.9.

9. A hydrocarbon conversion process which comprises effecting rearrangement of hydrocarbon molecules in the presence of hydrogen and a catalyst consisting essentially of a mechanical mixture of particles of less than about 100 microns in diameter of: (1) particles consisting of a carrier comprising predominantly alumina having deposited thereon an amount of a metal of the platinum series such that the ultimate catalyst has a content of said metal between about 0.05 and about 5 percent by weight and; (2) particles consisting of a porous inert carrier having deposited thereon an amount of an oxide of a rare earth metal selected from the group consisting of ceria and samaria such that the ultimate catalyst has a rare earth metal oxide content of between about 0.1 and about 40 percent by weight, the relative weight fractions of the two components being between about 0.1 and about 0.9; separating the catalyst from the reaction products; separating the catalyst particles (1) and (2) from each other; independently regenerating the separated catalyst particles (1) and (2); and remixing the regenerated catalyst particles (1) and (2) with each other for further use in eifecting hydrocarbon rearrangement.

10. A hydrocarbon conversion catalyst consisting essentially of a mechanical mixture of finely divided particles of: (1) particles consisting of a carrier comprising predominantly alumina having deposited thereon an amount of a metal of the platinum series such that the ultimate catalyst has a content of said metal between about 0.05 and about 5 percent by weight and; (2) particles consisting of a porous inert carrier having deposited thereon an amount of an oxide of a rare earth metal selected from the group consisting of ceria and samaria such that the ultimate catalyst has a rare earth metal oxide content of between about 0.1 and about 40 percent by weight, the relative weight fractions of the two components being between about 0.1 and about 0.9.

References Cited by the Examiner UNITED STATES PATENTS 2,814,599 11/1957 Lefrancois et al. 252466 2,854,403 9/1958 Weisz 252466 2,854,404 9/ 1958 Prater et al. 252-466 2,905,632 9/1959 Gladrow et al. 208138 2,976,232 3/1961 Porter et al 208-138 3,002,921 10/1961 Gladrow et al. 208l38 ALPHONSO D. SULLIVAN, Primary Examiner.

Claims

4. A PROCESS FOR REFORMING A HYDROCARBON MIXTURE WHICH COMPRISES CONTACTING SAID MIXTURE UNDER REFORMING CONDITIONS IN THE PRESENCE OF HYDROGEN WITH A CATALYST CONSISTING ESSENTIALLY OF A MECHANICAL MIXTURE OF PARTICLES OF LESS THAN ABOUT 100 MICRONS IN DIAMETER OF: (1) PARTICLES CONSISTING OF A CARRIER COMPRISING PREDOMINATELY ALUMINA HAVING DEPOSITED THEREON AN AMOUNT OF A METAL OF THE PLATINUM SERIES SUCH THAT THE ULTIMATE CATALYST HAS A CONTENT OF SAID METAL BETWEEN ABOUT 0.05 AND ABOUT 5 PERCENT BY WEIGHT, AND (2) PARTICLES CONSISTING OF A POROUS INERT CARRIER HAVING DEPOSITED THEREON AN AMOUNT OF AN OXIDE OF A RARE EARTH METAL SELECTED FROM THE GROUP CONSISTING OF CERIA AND SAMARIA SUCH THAT THE ULTIMATE CATALYST HAS A RARE EARTH METAL OXIDE CONTENT OF BETWEEN ABOUT 0.1 AND ABOUT 40 PERCENT BY WEIGHT, THE RELATIVE WEIGHT FRACTIONS OF THE TWO COMPONENTS BEING BETWEEN ABOUT 0.1 AND 0.9.