US2781323A

US2781323A - Method of producing a platinum catalyst on refractory oxide support

Info

Publication number: US2781323A
Application number: US357636A
Authority: US
Inventors: William K Hunter
Original assignee: Universal Oil Products Co
Current assignee: Universal Oil Products Co
Priority date: 1953-05-26
Filing date: 1953-05-26
Publication date: 1957-02-12
Anticipated expiration: 1974-02-12

Description

MnTnonoF PRODUCING A PLATINUM CATA- LYST N REFRACTORY oxmn sorronr Claims. (Cl. 252-442 This invention relates to processes for the conversion of hydrocarbons and to the manufiacture of catalysts for use therein. It more specifically relates to a process for the reforming of gasoline in the presence of a catalyst prepared in a specific manner.

The term reforming is well-known in the petroleum industry and refers to the treatment of gasoline fractions to improve the anti-knock characteristics thereof. The petroleum fraction that is rip-graded in reforming may be a full boiling range straight run gasoline having an initial boiling point within the range of from about 50 F. to about 100 F. and an end boiling point within the range of from about 350 F. to about 425 F. It may also be a natural gasoline as obtained from the refining of natural gases or it may be any selected fraction of the natural gasoline. The natural gasoline or the natural gasoline fraction will have an initial boiling point and an end boiling point substantially the same as that of the gasoline hereinbefore described. In the reforming process the gasoline fraction that is selected usually is the higher boiling fraction commonly referred to as naphtha and generally will have an initial boiling point of from about 150 F. to about 250 F. and an end boiling pointwithin the range of from about 350 F. to about 425 F. The catalyst of the present invention may also be applied to the reforming of cracked gasoline or mixtures of cracked and straight run and/or natural gasoline. Reference to gasoline in the present specification and claims therefore means a full boiling range gasoline or any fraction thereof and also that the gasoline fraction may contain components boiling above the gasoline range.

In the reforming process there are four major reactions.

The first is an aromatization reaction in which naphthene hydrocarbons are converted to aromatics. Thesecond is a dehydrocyclization reaction in which the straight chain or slightly branched chain parafiins are cyclicized to form aromatics. Third is an isomerization reaction in which straight chain or slightly branched chain paraifins are converted to more branched chain parafiins. This reaction occurs as a result of a strain put upon a carbon to carbon bond so that there is a shift of a carbon atom in the molecule to form a more branched chain molecule. in this specific reaction there is no change of molecular weight. The reaction may also be characterized as increasing the number of methyl groups in the hydrocarbon molecule. The fourth is a cracking reaction in which the heavier straight chain or slightly branched chain parafi'ins, which have low antiknock characteristics, 18.16 converted to lighter straight chain or branched chain paraffins which have higher antiknock characteristics. When this last reaction is conducted in the presence of hydrogen, the unsaturated hydrocarbon which is formed as a result of the cracking operation is saturated t-o the paraflin by reaction with hydrogen in the presence of the reforming catalyst. The cracking or splitting of the carbon to carbon bond is one of the more important reactions in a successful reforming process. It is necessary that the splitting of the ited States Patent "ice carbon to carbon bond be controlled so that there is no ex cessive formation of normally gaseous products. For e3 ample, it would be possible to crack a C10 hydrocarbon to form ten molecules of methane, however, unless methane is the specifically desired product, it would be uneconom-f ical in a reforming process to crack the C10 hydrocarbon to form methane. It is more desirable to crack'ta Ci'q hydrccznbon so that two molecules of pentane are formed and it would be still more desirable if during the reaction, isomerization would simultaneously take place so that the product obtained would be isopentane. It is an objectv of the present invention to provide a catalyst wherein the, cracking activity is controlled and selective so that ex-- cessive amounts of normally gaseous products are not produced inareforming process. p

Uncontrolled or non-selective cracking results in the more rapid formation of larger quantities of coke or carbonaceous matter which deposits on the catalyst and decreases or destroys its activity to catalyze the desired reactions. This in turn results in shorter processing cycles or periods with the necessity of more frequent regeneration of the catalyst by burning the carbonaceous products therefrom, or should the catalyst activity be destroyed it, will be necessary to shut down the unit to remove the old catalyst and repiace it with new catalyst.

l lydrocracking of parafiins and dehydrogenation of naphthenes are the principal reactions that are promoted by these catalysts which are capable of increasing the octane number of gasoline and naphtha to values that are substantially higher than those that ordinarilycan be reached by thermal reforming. In addition the yield octane number relationships realized with these catalysts are much better than are the corresponding relationships obtained in thermal reforming and in most of the prior By appropriate selection, or" operating conditions these catalysts can be used for a number of months and even years withoutregeneration'...

catalytic reforming processes.

While the catalyst-of the presentinvention is particu-. larly suitable for the reforming of gasoline it is under-- stood that this novel catalyst may be utilized for the conversion ofother hydrocarbon fractions. Thus the oat aly st may be used for the dehydrogenation of selected hydrocarbon fractions such as naphthenes to produce aromatics the dehydrogenation of parafiins to producethe corresponding olefins, the dehydrogenation of monoolefins to diolefins, etc.

sion of normalhexane to benzene. The catalystmay also.

be used to effect isomerization reactions and hydrogenation reactions, including non-destructive hydrogenation and destructive hydrogenation. In still another embodiment the catalyst of the present invention may be used for efiecting oxidation of hydrocarbons to form the corre-v spending oxide and desulfurizing sulfur-containing fractions.

method of uniformly distributing an acidic component throughout an inorganic refractory oxide whichcom prises forming particles containing said. acidic com.-

ponent and said inorganic refractoryoxide, calcining said particles at a temperature of from about 400 F. to about 1600 R, and subsequently submerging said calcined particles in liquid Water in an amount and for a time sufiicient to distribute said acidic component uniformly ganic refractory oxide, calcining the composite at atemw perature of from about 400 Etc about 1600? F., sub merging said calcined compositein liquid water in an The catalyst may also be utilized to effect dehydrocyclization reactions such asthe conver: 1

In one embodiment the present invention relates to a V amount and for a time sufficient to distribute said acidic component uniformly throughout said composite and combining therewith an active metal component.

In a specific embodiment the present invention relates to a method of preparing a catalyst which comprises combininga halogen with alumina in an amount of from about 0.1% to about 8% by weight of said alumina on a dry basis, calcining the composite at a temperature of from about 400 F. to about 1600 F., submerging said calcined particles in liquid water for a period of at least one minute thereby distributing said halogen uniformly throughout said particles, subsequently commingling with said particles a solution of a platinum compound in anamount to form a final catalyst containing from about 0.01% to about 1% by weight of platinum and heating the composite at a temperature of from about 500 F. to about 1100 F. 7

In a further embodiment the present invention relates to a process for the conversion of a hydrocarbon which comprises subjecting said hydrocarbon to contact at conversion conditions with a catalyst prepared by calcining a composite of an acidic component and an inorganic refractory oxide at a temperature of from about 400 F. to about 1600 F., submerging said calcined composite in liquid Water in an amount and for a time suflicient to distribute said acidic component uniformly throughout said composite and combining therewith an active metal component.

In another specific embodiment the present invention relates to a process for reforming a straight run gasoline fraction which comprises subjecting said fraction to contact at a temperature of from about 500 F. to about 1000 F., a pressure of from about 50 to about 1000 pounds per square inch, and a weight hourly space velocity of from about 0.5 to about in the presence of from about 0.5 to about 20 mols of hydrogen per mol of hydrocarbon with a catalyst prepared by combining a halogen with alumina in an amount of from about 0.1% to about 8% by weight of said alumina on a dry basis, calcining the composite at a temperature of from about 400 F. to about 1600 F., submerging said calcined particles in liquid Water for a period of at least one minute ,thereby' distributing said halogen uniformly throughout said particles, subsequently commingling with said particles a solution of a platinum compound in an amount to form a final catalyst containing from about 0.01% to about 1% by weight of platinum and heating the composite at a temperature of from about 500 F to about 1100 F.

In aceordancewith the present invention a composite of an acidic component and an inorganic refractory oxide, whlch 1s usually the cracking-component, is calcined at a temperature of from about 400 F. to about 1600 F. pr or .to further treatment. One cracking component comprises at least two inorganic refractory oxides. Another cracking component comprises a refractory inorganic oxide and halogen. The halogen is the acidic component in this catalyst. Suitable but not necessarily equivalent inorganic refractory oxides comprise the oxides of aluminum, silicon, zirconium, zinc, titanium, magnesium, cadmium, gallium, iridium, thallium, germanium, tin, cerium, lead, thorium, vanadium, columbium, tantalum, chromium, molybdenum, tungsten, uranium, manganese, etc. Preferred combinations for the cracking component which comprises at least two inorganic refractory oxides are alumina-silica, alumina-titania, alumina-boron oxide, silica-magnesia, silica zirconia, silicathoria, etc. The preferred oxides for the cracking component which comprises a refractory oxide and halogen are the oxides of aluminum, zirconium, zinc, titanium, magnesium, and cadmium, however, not necessarily with equivalent results. Combinations of .two or'more of these oxides, for example alumina-silica, alumina-zirconia, etc., may be used for compositing withthe halogen within the scope of this invention, but again not necessarily with equivalent results. The cracking component preferably contains halogen since it has been found that the halogen will more readily distribute itself uniformly throughout the other component or components of the catalyst when submerged in liquid water for a sufiicient period of time.

In the alumina-silica composite it is the particular association of the alumina with the silica that gives the catalyst its acidic and cracking properties. Silica alone or alumina alone has little if any cracking activity, however, for example, starting with alumina, when silica is composited therewith the fact that silica is added gives the catalyst its acidic and cracking properties and therefore the silica may be termed the acidic component. Likewise starting with silica and adding alumina, alumina may likewise be called an acidic component.

he halogen includes fluorine, chlorine, iodine, and bromine. The preferred halogen comprises fluorine and chlorine. In general, fluorine appears to be less easily removed from the catalyst and of higher activity and, therefore, is preferred in many cases. It is understood that the halogen may comprise a mixture of two or more of the halogens, a preferred mixture comprising fluorine and chlorine.

Another component of the catalyst comprises a metal or a compound of a metal selected from group VIII of the periodic table. While platinum and its compounds are preferred components it is understood that other suitable members of group VIII and particularly of the platinum group may be employed. These other components may include, although not necessarily with equivalent results, the metals or compounds of nickel, cobalt, palladium, iridium, etc. or mixtures of two or more thereof.

It is understood that the various combinations of components which may be prepared and used in accordance with the present invention are not necessarily equivalent.

In general, the refractory oxide or mixture of the oxides will comprise a major proportion of the catalyst and thus" will range from about 75% to about 99.8% by weight of the catalyst composite. The halogen will generally be used in amounts of from about 0.1% to about 10% by weight of the final catalyst. When fluorine is the halogen it will be used in amounts of from about 0.1% to about 5% by weight of the final catalyst and when chlorine is the halogen it will generally be used in amounts of from about 0.1% to about 8% by weight of the final catalyst. As mentioned the halogen may comprise a mixture of two or more halogens and the total amount of halogen will generally be within the ranges herein set forth..

The concentration of the metal component selected from the metals and compounds of the metals in group VIII of the'periodic table will generally be comparatively lower than the inorganic refractory oxide components. The concentration of the metal component selected from group VIII of the periodic table will generally be from about 0.01% to' about 10% by weight of the final catalyst.

t. is understood that when desired two or-more metals or compounds of metals of this group may lie-utilized in the catalyst composite.

The cracking component of the catalyst of the present invention may be made in any suitable manner including separate,successive, or coprecipitation methods. The refractory oxide may beprepared in any suitable manner. For example, alumina may be prepared by adding a rcagent such as ammonium hydroxide, ammonium carbonate, etc. to a salt of aluminum such as aluminum chloride, aluminum nitrate, aluminum acetate, etc., in an amount to form aluminum hydroxide, which upon drying is converted to alumina. In the present specification and claims the aluminum hydroxide is referred to as. alumina in order that the percentages are based on the alumina free of combined water. It has been found that a chloride of aluminum is generally preferred as the aluminum salt to be used, not only for convenience in subsequent washing and filtering procedures but also it appears to give best results. After the alumina has been formed it .is generally washed to remove soluble impurities. Usual Washing procedures comprise washing with water either in combination with filtering or as separate steps. It has been found that filtration of the alumina is improved when the Wash water contains a small amount of ammonium hydroxide. The ordinary washing may generally depend upon whether ail or a part of the chlorine is to be retained in the catalyst composite. When chlorine is not desired the alumina is washed thoroughly to remove substantially all of the chlorine. On the other hand, if part of the chlorine is to be retained in the catalyst'the washing is less severe. In general, it is preferred to wash the alumina thoroughly and if chlorine is desired'it is added as a separate step because better control of the amount of chlorine is obtained in this manner. Alumina spheres may be continuously prepared by passing droplets of an alumina sol into an oil bath maintained at an elevated temperature and retaining the droplets in said oil bath until the droplets set to firm gel spheres. The spheres are continuously withdrawn from the oil bath and immediately thereafter aged prior to being contacted with water or aqueous solution.

Silica may be prepared in any suitable manner, one method being to commingle water glass and a mineral acid under conditions to precipitate a silica hydrogel. The

. silica hydrogel is washed with Water containing a small amount of electrolyte to remove sodium ions. Oxides of other compounds may be prepared by reacting a basic reagent such as ammonium hydroxide, ammonium carbonate, etc., with an acid salt solutionof the metal as, for example, the chloride, sulfate, nitrate, etc., or by adding an acid to an alkali salt of the metal as, for example, commingling sulfuric acid with sodium aluminate, etc. Usually the metal oxide will be washed and filtered whichmay be done in the same or separate steps and may be effected in the presence of an acid or a base as desired. When it is desired to prepare the catalyst in the form of particles of uniform size and shape, this may readily be accomplished by grinding the partially dried oxide cake with a suitable lubricant such as stearic acid, rosin, graphite, etc. and then forming the particles in any suitable pelleting or extrusion apparatus.

When the cracking component comprises at least two refractory inorganic oxides the composite may be prepared in any suitable manner including separate, successive, or coprecipitation methods. In the separate precipitation method the oxidesareprecipitated separately and then mixed, preferably in the wet state. When successivepreeipitation methods are employed the first refrac tory inorganic oxide is precipitated, as hereinbefore 'set forth, and then the wet slurry, either with or Without prior Washing may be, composited with-a salt of the other component and precipitation of the oxide is effected by the addition of a suitable base or acid as required. This composite may then be dried and formed into particles.

Cracking components comprising silica-alumina and silica-alumina-zirconia are preferably manufactured by comminglinganacid such as hydrochloric acid, sulfuric acid, etc., with commercial water glass under. conditions to precipitate silica, washing with acidulated water or otherwise to remove sodium ions, commingling with an aluminum salt such as aluminum chloride, aluminum sulfate, aluminum nitrate and/or zirconium salt, etc., and either adding a basicprecipitant such as ammonium hydroxide to precipitate alumina and/or zirconia, or forming the desired oxide or oxides by thermal decomposition of the salt as the case may permit. The silicaalumina-zirconia crackingcomponent may be formed by adding the aluminum and/or ,zirconium .salts together or separately. The other crtkkingcomponets may .be

prepared in a similar manner, however, not necessarily with equivalent results.

The halogen may be added to the catalyst in any suitable manner and either before or after precipitation of the oxide. While the halogen may be utilized as such, it generally is preferred to utilize the halogen as an aqueous solution of the hydrogen halide for ease in handling. In the preferred method the halogen is added to the refractory oxide before the other components are composited therewith. When alumina is the selected refractory oxide the halogen is preferably incorporated into the alumina before forming into particles and thismay be accomplished by the use of an acid such as hydrogen fluoride, hydrogen chloride, hydrogen bromide, and/or hydrogen iodide. In some cases volatile salts such as ammonium fluoride, ammonium chloride, etc., may be employed. In any event, the amount of halogen will be in the range of from about 0.1% to about 10% by weight of the final catalyst. Chemically combined fluorine appears to be more active and therefore will be used within the range of from about 0.1% to about 5% by weight of the refractory oxide on a dry basis. The chlorine content will generally be within the range of from about 0.1% to about 8% and preferably from about 0.2% to about 5% by weight of the final catalyst on a dry basis.

in the prior art various methods of achieving uniform cracking activity on the various particles of the catalyst have been discussed. It is desirable that the cracking component be uniformly distributed throughout the catalyst mass in order that a better control of the reactions may be had and, further, I have found that when a uniform cracking component is further composited with an active metal component, that it is necessary that the cracking component have uniformity throughout the entire catalystmass in order to have the metal component urdformly distributed throughout the catalyst mass. For example, halogen may be composited with several pounds of alumina spheres and upon individual examination of the spheres it may be found that the halogen is not uniformly distributed therethrough,that is the halogen concentration on some of the spheres will be higher than on others. The cracking activity of the catalyst mass, therefore, will be non-uniform and further when this composite is further composited with an active metal component the active metal component will not be uniformly distributed throughout the entire mass. For this reason it is seen thatit is desirable to have the halogen uniformly distributed.

I have invented a method of uniformly distributing a halogen throughout an inorganic refractory oxide which comprises forming particles containing said halogen and said inorganic refractory oxide, calcining said particles at a. temperature of from about 400 F. to about 1600 F., and subsequently submerging said calcined particles in liquid water in an amount and for a time sufiici'ent to distribute said halogen uniformly throughout said particles. When the particles of halogen and inorganic refractory oxide are submerged in water prior to calcination, the halogen does not readily distribute'itself throughout the inorganic refractory oxide. It is my theory, hoW- ever, I do not intend my invention to be limited thereto, that the halogen prior to impregnation-is in a form wherein it is intimately combined with the alumina and is tenaceously held. After the calcination, however, it appears that the halogen is in a more mobile formand when, subsequent to the calcination, the particles are contacted with liquid Water, the halogen more readily distributes itself uniformly throughout the inorganic refractory oxide mass.

As herein mentioned the composite of halogen and the inorganic refractory oxide is subjected to a calcining operation prior to submerging in .liquid water. The calcination is conducted at a temperature of from about 400 .F. to about 1600" F. or more but usually notin excess of 1400 F. The heattreatment or-calcinationmaybeconducted in an oxidizing atmosphere such as air or oxygen,

avreducing atmosphere such as hydrogen or an inert atmosphere such as nitrogen, etc. In some cases the calcination may take place in air followed by heat treatment in the presence of hydrogen or the reverse procedure may be used. 'The calcination is more usually and preferably conducted in air or other oxygen-containing gas. The periods of the calcination may vary widely from about as low as minutes to 8 hours or more.

In accordance with the present invention after this calcination treatment the particles are submerged in liquid water in an amount and for a time sufficient to distribute said acidic component uniformly throughout said particles. It is not suflicient that the calcined particles merely be wetted since in this manner the halogen on one particlemay not'shift or migrate to other adjacent particles. It is thus necessary that a water bridge occur between all of the particles which are to be made uniform and the most convenient and simplest method of achieving this result is to completely submerge the particles in liquid water. The pills may be submerged by adding them to water or water may be added to the pills.

The distributing of the halogen or other acidic component throughout the inorganic refractory oxide thus necessarily takes place in liquid Water and the temperatures that the liquid water may be utilized at range from the freezing point of water of 32 F. to the critical point of water of 705 F. When temperatures above the boiling point of water are utilized it is necessary to maintain a pressure on the system suflicient to keep the water in the liquid phase. The time that is required to achieve this uniform distribution varies inversely with the temperature. At lower temperatures longer contacting times are required and conversely with higher temperatures shorter processing times may be used. In general at room temperature the particles are submerged in water for a period of about 8 hours and at higher temperatures of from about 175 F. to about 300 F. the time of submerging of the particles in liquid water will be about one minute. The time the particles are submerged, therefore, is at least one minute.

After the halogen or other acidic component has accordingly been uniformly distributed throughout the inorganic refractory oxide mass, the active metal component is composited with the cracking component. In a preferred embodiment of the present invention platinum is subsequently composited with the cracking component generally in an amount of from about 0.01% to about 1% by weight of the catalyst. Platinum is a particularly desirable metal component to be'incorporated into the catalyst since catalysts containing low concentrations of platinum have been found to be very active, especially when the catalyst is to be used in reforming operations. The metal component selected from metals and compounds of the metals in group VIII of the periodic table may be incorporated into the catalyst in any suitable manner and may be composited immediately subsequent to submerging the calcined particles in liquid water or the calcined particles may be submerged in liquid. water and then dried or calcined before adding the active metal component.

When platinum is the selected active metal component one method of introduction is to form a separate solution of chloroplatinic acid and water and to introduce hydrogen sulfide into this solution at room temperature until the chloroplatinica-cid solution reaches a constant coloration, that is there will be no change in color upon addition of more hydrogen sulfide. A chloroplatinic acid solution is'normally light yellow and upon addition of hydro gen sulfide gas turns to a dark brown color. Apparently the chloroplatinic acid and hydrogen sulfide react to form one or more complexes or chemical compounds. The brown solution of chloroplatinicacid and hydrogen sulfide may then be commingled with the other components of the catalyst as hereinbeforeset forth,

Another method of introducing the platinum into the catalyst is to form a separate aqueous solution of chloro platinic acid and add ammonium hydroxide to give a solu' tion having a pH between the range of from about 5 to about 10. This solution is then commingled with the other components of the catalyst. Although the platinum is preferably introduced as a solution of chloroplatinic acid other suitable platinum solutions may be employed such as solutions, colloidal solutions or suspensions of platinum cyanide, platinum hydroxide, platinum oxide, platinum sulfide, etc. In cases where these solutions are not soluble in water at the temperatures used other suitable solvents such as alcohol, ethers, etc., may be utilized.- The platinum appears to enter into a peculiar association with the other components of the catalyst and thereby serves to improve the antiknock characteristics of the product obtained in processes in which the catalyst is used. While platinum is a preferred component it is understood that other suitable components selected from the metals and compounds of the metals in group VIII of the periodic table may be employed. These components include, although not necessarily with equivalent results, nickel, cobalt, ruthenium, rhodium, osmium, iridium, palladium, etc., compounds thereof, or mixtures of two or more of these metals or compounds of these metals.

The concentration of the metal component selected from group VIII will vary according to the particular component selected and the conversion process in which it is to be used, however, the concentration generally will lie within the range of from about 0.01% to about 10% by weight of the final catalyst (calculated as the metal).

The catalyst composite after all of the components of the catalyst are present therein is usually subjected to a high temperature treatment. The heat treatment or calcination may be conducted in an oxidizing-atmosphere, a reducing atmosphere such as hydrogen, methane etc., or an inert atmosphere such as nitrogen etc., however, the calcination is preferably conducted in air or other oxygencontaining gas. The final calcination is performed at a temperature within the range of from about 500 F. to about 1100 F. The preferred heating periods are from about 1 to 8 hours or more.

Although the catalyst of the present invention will have a long life it may be necessary to regenerate the catalyst after long periods of service. The regeneration may be effected by treatment with air or other oxygencontaining gas to burn the carbonaceous material therefrom. In general it is preferred to control the regenera tion temperature not to exceed about 1100 F.

As hereinbefore set forth these catalysts are particularly suitable for use in the reforming of gasoline or fractions thereof. The exact operating conditions depend upon the character of the charging stock as well as the activity of the catalyst being used. However, the conditions usually will be in the following ranges: temperature from about 500 F. to about 1000 F., a pressure of from about 50 to about 1000 pounds per square inch or more, weight hourly space velocity (defined as the weight of oil per hour per weight of catalyst in the reaction zone) of from about'0.5 to about 20 or more. The reforming is preferably effected in the presence of hydrogen which may be introduced from an extraneous source or recycled from within the process. In the preferred mode of operation sutficient hydrogen is produced and recycled so that no extraneous source of hydrogen is necessary. A hydrogen to hydrocarbon mol ratio of from about 0.5 to about 20 or more mols of hydrogen per mol of hydrocarbon is usual.

Processes using the catalyst of the present invention may be effected in any suitable equipment. The catalyst may be deposited as a fixed bed in a reactor and the hydrocarbons to be treated are passed therethrough in either upward or downward flow. The catalyst may be used in a fluidized type of operation in which the catalyst and hydrocarbons are maintained in a state of turbulence under hindered settling conditions or a fiuidized fixed bed type of operationmay housed in whichthecatalyst and hydrocarbons are maintained in a stateof-turbulence under hindered settling conditions but where catalyst is not withdrawn from or introduced into the reaction-zone during the processing cycle. The catalyst may also be used in the moving bed type of process in which the catalyst and hydrocarbons are passed either in concurrent or countercurrent now through a reaction zone and the catalyst may also be used in the suspensoid type of operation in which the catalyst and hydrocarbons are passed as a slurry through the reaction zone. The reactants from any of the hereinbefore mentioned reaction zones are normally subjected to a further treatment such as the stabilization of the product to separate normally gaseous products therefrom and to obtain a final reformed product of the desired volatility and vapor pressure.

The following example is given to illustrate my invention but is not intended for the purpose of unduly limiting the generally broad scope of the present invention.

Example An alumina sol was prepared by digesting aluminum metal in a dilute hydrochloric acid solution at an elevated temperature. The resultant sol contained from about 26% to about 28% A1203. A hexamethylene tetramine solution was prepared by adding 291 grams of hexamethylene tetramine to form 1 liter of solution. The sol and solution were passed, each at an equal rate, into a mixer. The mixture was then passed through a nozzle and into a forming chamber filled with Nujol. The forming chamber was maintained at a temperature of 195 F. The droplets assumed substantially spherical shape during passage through the Nujol and were removed from the lower portion of the forming chamber by means of a stream of Nujol maintained at a temperature of 195 F. The Nujol stream containing the spheres was passed into another zone in which a level of Nujol was maintained. This second zone likewise was main tained at a temperature of about 195 F. The spheres were maintained in this zone for 16 hours.

The partially aged spheres were then further aged in an ammonium hydroxide solution for 24 hours at 203 F. The aging solution was then drained and the spheres were washed with water containing a small amount of ammonium hydroxide. A 4.8% aqueous solution of hydrogen fluoride was added in an amount to produce a final catalyst containing 0.45% combined fluorine by weight. The spheres were then further washed with water. The washed spheres were then partially dried at a temperature of 248 F. The dried spheres were immediately calcined thereafter at a temperature of 1200 F. for 3 hours.

A random sample of approximately 20 cc. of the calcined base was divided into two equal portions. One sample portion was covered with brom thymol blue indicator solution. After about one minute the indicator was removed from the spheres and they were given a water rinse. The spheres were then noted to be colored in varying degrees between yellow and blue indicating a wide range in acidity in the limits of the indicator (6-7.5 pH).

The other sample portion was placed in a test tube and covered with cold water. The water and sample were heated to about 210 F. and maintained there for approximately one minute. The total time of submersion of the pills was about two minutes. The pills were then cooled to room temperature.

These spheres were then tested with brom thymol blue as was the first portion of the sample. In this case the spheres were noted to be uniformly blue in coloration.

The results of the above experiment show that the halogen, or acidic component of the catalyst will uniformly distribute itself throughout a calcined halogen-inorganic refractory oxide composite when submerged in liquid water.

When the first batch "of spheres is further impregnated with a chloroplatinic acid solution the calcined catalyst will have various concentrations of platimrm on the spheres when one sphere is compared to another and when used in a reforming operation the catalyst will show varying degrees of activity when one sphere is compared to another, due to variations in the halogen and platinum concentrations.

When the second batch of spheres is impregnated with a chloroplatinic acid solution the platinum is uniformly distributed throughout the spheres and when used in a reforming operation the spheres will have uniform activity from one sphere to the other.

I claim as my invention:

1. A method of manufacturing a catalyst which comprises compositing a halogen component with an inorganic refractory oxide, calcining the composite at a temperature of from about 400 F. to about 1600 F., submerging said calcined composite in liquid water in an amount and for a time sufficient to distribute said halogen component uniformly throughout said composite, and subsequently adding to the thus treated composite an active metal component containing a metal in group VIII of the periodic table.

2. The method of claim 1 further characterized in that said halogen component comprises fluorine.

3. The method of claim 1 further characterized in that said inorganic refractory oxide comprises alumina.

4. The method of claim 1 further characterized in that said active metal component comprises platinum.

5. A method of preparing a catalyst which comprises forming particles of a halogen component and an inorganic refractory oxide, calcining said particles at a temperature of from about 400 F. to about 1600 F., contacting said calcined particles with liquid water in an amount and for a time sufiicient to distribute said halogen component uniformly throughout said particles, subsequently adding to the thus treated particles an active metal component selected from the group consisting of platinum and palladium and compounds thereof in an amount to form a final catalyst containing from about 0.01% to about 1% by weight of said metal component (calculated as the metal), and heating the composite at a temperature of from about 500 F. to about 1100 F.

6. A method of preparing a catalyst which comprises combining a halogen with alumina in an amount of from about 0.1% to about 8% by weight of said alumina on a dry basis, calcining the composite at a temperature of from about 400 F. to about 1600 F., submerging said calcined composite in liquid Water for a period of at least one minute, thereby distributing said halogen uniformly throughout said composite, subsequently commingling with the thus treated composite a solution of a platinum compound in an amount to form a final catalyst containing from about 0.01% to about 1% by weight of platinum, and heating the composite at a temperature of from about 500 F. to about 1100" F.

7. The method of claim 6 further characterized in that said halogen comprises fluorine in an amount of from about 0.1% to about 5% by weight of said alumina on a dry basis.

8; The method of claim 6 further characterized in that said halogen comprises chlorine in an amount of from about 0.1% to about 8% by Weight of said alumina on a dry basis.

9. A method of catalyst manufacture which comprises calcining a halogen-containing refractory oxide at a temperature of from about 400 F. to about 1600 F., soaking the calcined material in liquid water for a time sufficient to distribute the halogen uniformly throughout the oxide, and subsequently compositing with the thus treated material an active catalyst component comprising a metal in group VIII of the periodic table.

10. A method of catalyst manufacture which comprises calcining a halogen-containing alumina at a temperature 11 12 of from about 400 F. to about 1600 F., soaking the References Cited in the file of this patent calcined material in liquid water for a time suflicient to UNITED STATES PATENTS distribute the halogen uniformly throughout the alumina, and subsequently compositing platinum with the thus 2,4721) Ha'ensel 161 1949 treated halogen-containing alumina. 5 1,136 Haensel 1953 2,667,461 Guyer et a1 Jan. 26, 1954

Claims

1. A METHOD OF MANUFACTURING A CATALYST WHICH COMPRISES COMPOSITING A HALOGEN COMPONENT WITH AN INORGANIC REFRACTORY OXIDE, CALCINING THE COMPOSITE AT A TEMPERATURE OF FROM ABOUT 400* F. TO ABOUT 1600* F., SUBMERGING SAID CALCINED COMPOSITE IN LIQUID WATER IN AN AMOUNT AND FOR A TIME SUFFICIENT TO DISTRIBUTE SAID HALOGEN COMPONENT UNIFORMLY THROUGHOUT SAID COMPOSITE, AND SUBSEQUENTLY ADDING TO THE THUS TREATED COMPOSITE AN ACTIVE METAL COMPONENT CONTAINING A METAL IN GROUP VIII OF THE PERIODIC TABLE.