Reforming catalyst with homogeneous metals dispersion

A novel extruded catalyst and process use thereof is disclosed. The catalyst comprises a refractory inorganic oxide and halogen, platinum-group metal, and Group IVA(14) metal components, wherein the Group IVA(14) metal is homogeneously dispersed within a bed of catalyst particles relative to catalysts of the prior art. Utilization of this catalyst in the reforming of hydrocarbons results in significantly improved selectivity to the desired gasoline product.

FIELD OF THE INVENTION 
This invention relates to an improved catalyst for the conversion of 
hydrocarbons, and more specifically for the catalytic reforming of 
gasoline-range hydrocarbons. 
BACKGROUND OF THE INVENTION 
The subject of the present invention is a novel catalyst with homogeneous 
metals dispersion which features exceptional selectivity to desired 
products when employed in a hydrocarbon conversion process requiring a 
catalyst having both a hydrogenation-dehydrogenation function and a 
cracking function. More precisely, the present invention involves a novel 
dual-function catalyst characterized by low standard deviation of the 
local concentration of a Group IVA(14) metals component relative to the 
bulk concentration in a bed of catalyst particles which surprisingly 
enables substantial improvements in hydrocarbon conversion processes that 
have traditionally used a dual-function catalyst. Metals of Group IVA 
(IU 14) of the Periodic Table [See Cotton and Wilkinson, Advanced 
Inorganic Chemistry, John Wiley & Sons (Fifth Edition, 1988)] having 
utility in the present invention are one or more of tin, germanium and 
lead. 
In another aspect, the present invention comprehends improved processes 
that emanate from the use of the novel catalyst. In a specific aspect, an 
improved reforming process utilizes the subject catalyst to increase 
selectivity to gasoline and aromatics products. In an alternative aspect, 
the present catalyst is employed in a process for the dehydrogenation of 
dehydrogenatable hydrocarbons. 
Catalysts having a hydrogenation-dehydrogenation function and a cracking 
function are used widely in many applications, particularly in the 
petroleum and petrochemical industry, to accelerate a wide spectrum of 
hydrocarbon-conversion reactions. The cracking function generally is 
thought to be associated with an acid-action material of the porous, 
adsorptive, refractory-oxide type which is typically utilized as the 
support or carrier for a heavy-metal component, such as the Group 
VIII(8-10) metals, to which is generally attributed the 
hydrogenation-dehydrogenation function. 
These catalysts are used to accelerate a wide variety of 
hydrocarbon-conversion reactions such as dehydrogenation, hydrogenation, 
hydrocracking, hydrogenolysis, isomerization, desulfurization, 
cyclization, alkylation, polymerization, cracking, and hydroisomerization. 
In many cases, the commercial applications of these catalysts are in 
processes where more than one of these reactions are proceeding 
simultaneously. An example of this type of process is reforming wherein a 
hdydrocarbon feed stream containing paraffins and naphthenes is subjected 
to conditions which promote dehydrogenation of naphthenes to aromatics, 
dehydrocyclization of paraffins to aromatics, isomerization of paraffins 
and naphthenes, hydrocracking of naphthenes and paraffins and other 
reactions to products an octane-rich or aromatic-rich product stream. 
Another example is an isomerization process wherein a hdydrocarbon 
fraction which is relatively rich in straight-chain paraffin compounds is 
contacted with a dual-function catalyst to produce an output stream rich 
in isoparaffin compounds while converting any cyclics present to a mixture 
of paraffins and naphthenes by a combination of hydrogenation and ring 
opening. Yet another example is a hydrocracking process wherein catalysts 
of this type are utilized to effect selective hydrogenation and cracking 
of high molecular weight unsaturated materials, selective hydrocracking of 
high molecular weight compounds, and other reactions to produce a 
generally lower-boiling, more valuable output stream. 
Regardless of the reactions or the particular process involved, it is of 
critical importance that the dual-function catalyst exhibit the capability 
both to initially perform its specified functions efficiently and to 
perform them satisfactorily for prolonged periods of time. The parameters 
used in the art to measure how well a particular catalyst performs its 
intended functions in a particular hydrocarbon reaction environment are 
activity, selectivity and stability. In a reforming environment, these 
parameters are defined as follows: 
(1) Activity is a measure of the ability of the catalyst to convert 
hydrocarbon reactants to products at a designated severity level, with 
severity level representing a combination of reaction conditions: 
temperature, pressure, contact time, and hydrogen partial pressure. 
Activity typically is designated as the octane number of the pentanes and 
heavier ("C.sub.5 +") product stream from a given feedstock at a given 
severity level, or conversely as the temperature required to achieve a 
given octane number. 
(2) Selectivity refers to the percentage yield of petrochemical aromatics 
or C.sub.5 + gasoline product from a given feedstock at a particular 
activity level. 
(3) Stability refers to the rate of change of activity or selectivity per 
unit of time or of feedstock processed. Activity stability generally is 
measured as the rate of change of operating temperature per unit of time 
or of feedstock to achieve a given C.sub.5 + product octane, with a lower 
rate of temperature change corresponding to better activity stability, 
since catalytic reforming units typically operate at relatively constant 
product octane. Selectivity stability is measured as the rate of decrease 
of C.sub.5 + product or aromatics yield per unit of time or of feedstock. 
Programs to improve reforming-catalyst performance are being stimulated by 
the widespread removal of lead antiknock additive from gasoline and by the 
increasing requirements of high-performance internal-combustion engines, 
which magnify the requirement for gasoline "octane" or knock resistance of 
the gasoline component. The catalytic reforming unit must operate at 
higher severity in order to meet these increased octane needs. This higher 
severity results in lower yield of gasoline product, and catalyst 
selectivity becomes even more important to avoid excessive losses of 
valuable product to fuel by-product. The major problem facing workers in 
this area of the art, therefore, is to develop more selective catalysts 
with sufficient activity and stability to operate effectively at current 
high reforming severities. 
INFORMATION DISCLOSURE 
The prior art is replete with references to catalysts containing a Group 
IVA(14) metal component and a platinum-group-metal component. For example, 
U.S. Pat. No. 3,700,588 (Weisang et al.) teaches a catalyst comprising 
platinum and tin or lead on alumina, wherein the alumina is pretreated 
with hydrogen chloride and the tin is on the surface of the support. U.S. 
Pat. No. 3,702,294 (Rausch) discloses a catalytic composite containing 
platinum, tin and halogen components; Rausch discloses the incorporation 
of the tin in the composite by all conventional methods, with preferred 
methods being impregnation of the tin or incorporation of the tin in 
alumina hydrosol followed by oil dropping. U.S. Pat. No. 3,764,557 
(Kluksdahl) teaches a process for reactivating a catalyst comprising 
platinum and tin suitably impregnated to be uniformly disposed on the 
surface of the carrier. U.S. Pat. No. 3,775,301 (Hayes) discloses a 
catalytic reforming process characterized by a catalytic composite 
comprising platinum-group, germanium and rhenium; germanium is 
incorporated in the composite in any suitable manner, with impregnation or 
addition to alumina hydrosol followed by oil dropping being preferred. 
U.S. Pat. No. 4,032,475 (Knapik et al.) teaches a catalytic composite 
containing a platinum-group metal, tin and cobalt with a uniform 
distribution of the tin and platinum. U.S. Pat. No. 4,588,497 (Blanchard 
et al.) disclose a reforming process characterized by a catalyst 
comprising Group VIII(8-10) and additional metals, including tin, lead, 
and germanium, introduced preferentially into the binding agent or alumina 
charge. Applicants assert that the above patents do not provide the 
extruded catalyst of the present invention, wherein the homogeneous 
dispersion of Group IVA(14) metal is distinguished by a low standard 
deviation of concentration in a bed of catalyst particles. 
"Uniformly distributed" is contrasted with "surface-impregnated" metal 
component in U.S. Pat. No. 4,791,087 (Moser et al.). Platinum and Group 
IVA(14) metal components are uniformly dispersed, while the 
surface-impregnated metal component is selected from rhodium, ruthenium, 
cobalt, nickel, and iridium and has a concentration in the defined 
exterior surface at least 4 times greater than in the interior portion. 
"Uniformly distributed" thus refers to the absence of a concentration 
gradient between the exterior surface and the interior portion of a 
catalyst particle, in contrast to the homogeneous dispersion wtih low 
standard within a bed of catalyst particles. 
Silver grains are described as very uniformly deposited in U.S. Pat. No. 
4,690,913 (Nojiri et al.) when the loading of silver on the innermost 
layer of catalyst is 0.65 times (preferably 0.7 times) the loading on the 
outside surface layer. Nojiri et al. does not describe a Group IVA(14) 
component. Considering the range of metals loadings of Nojiri et al., 
differences in "very uniformly deposited" silver loadings could range from 
65 to about 150% which would be substantially more than variations 
characterized by the present invention. 
U.S. Pat. No. 4,169,040 (Bea et al.) teaches a heavy-oil conversion process 
characterized by a catalyst having standard deviation of less than 25% in 
concentrations of silica and various Group VIB and Group VIII(8-10) 
metals. Nickel, cobalt, molybdenum, tungsten and compounds thereof are 
disclosed. Bea et al. do not disclose a catalyst having a homogeneous 
Group IVA(14) metal component nor the advantages of using such catalyst in 
hydrocarbon conversion. 
The prior art thus teaches catalysts having platinum-group and Group 
IVA(14) metal components and also discloses that, in aspects that differ 
from the present invention, the distribution of the metals on a catalyst 
can affect its utility. However, the prior art relates to the presence or 
absence of a concentration gradient of Group IVA(14) metal within a 
catalyst particle rather than homogeneous dispersion within a bed of 
catalyst particles. Applicants believe that the art does not disclose or 
anticipate the extruded catalyst of the present invention, wherein the 
homogeneous dispersion of a Group IVA(14) metal component in a bed of 
catalyst particles provides surprising improvements in selectivity. 
SUMMARY OF THE INVENTION 
Objects 
It is an object of the invention to provide a novel catalyst for improved 
selectivity in hydrocarbon conversion. A corollary object of the invention 
is to provide a hydrocarbon-conversion process, particularly a reforming 
process showing improved selectivity to gasoline or aromatics product. 
SUMMARY 
This invention is based on the discovery that an extruded catalyst 
containing a homogeneously dispersed Group IVA(14) metal component and a 
platinum-group metal component in a bed of catalyst particles shows 
exceptional selectivity for hydrocarbon conversion. 
EMBODIMENTS 
A broad embodiment of the present invention is a bed of extruded catalyst 
particles comprising a refractory inorganic oxide, a halogen, a 
platinum-group metal and a Group IVA(14) metal having a local 
concentration in a bed of catalyst particles with a standard deviation of 
less than 25% of the bulk concentration. In a preferred embodiment the 
refractory inorganic oxide is alumina, the platinum-group metal is 
platinum, and the Group IVA(14) metal is tin. 
In an especially preferred embodiment, the standard deviation of the Group 
IVA(14) metal concentration is determined by scanning transmission 
electron microscopy. 
In another aspect, the invention is a preferred process for the reforming 
of hydrocarbons utilizing the present catalyst to achieve improved 
gasoline or aromatic yields. An alternative embodiment is a 
dehydrogenation process employing the present catalyst for greater 
selectivity to desired olefinic products. 
These as well as other objects and embodiments will become evident from the 
following more detailed description of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
To reiterate briefly, a broad embodiment of the present invention is a bed 
of extruded catalyst particles comprising a refractory inorganic-oxide 
support, a halogen component, a platinum-group-metal component, and a 
Group IVA(14) metal having a local concentration in a bed of catalyst 
particles with a standard deviation of less than 25% of the bulk 
concentration. 
The invention is characterized for a bed of catalyst particles, such as 
would be contained in a reaction vessel in a process unit for hydrocarbon 
conversion. The "bed of catalyst particles" is defined as an aggregate of 
extruded catalyst particles manufactured by substantially identical 
procedures in identical equipment from the same batches of raw materials. 
The catalyst particle of the present invention is an extrudate, preferably 
cylindrical in shape and having a diameter of about 0.8 to 3.2 mm 
(especially 1.5 to 2.2 mm) and a length to diameter ratio of about 1:1 to 
5:1, with 2:1 being especially preferred. 
The dispersion of metals on a sample of catalyst particles from the bed 
preferably is determined by scanning transmission electron microscopy. The 
scanning transmission electron microscope (STEM) combines technologies of 
the transmission electron microscope, for high resolution, and the 
scanning electron microscope, for imaging and chemical microanalysis. The 
catalyst particle is ground to a fine powder with a mortar and pestle, 
granules of the fine powder having a typical range of dimensions through 
the center of the granule of about 1000 to 5000 angstroms. An area on a 
granule of up to about 500 angstroms in diameter is examined by STEM to 
determine the local concentration of metals. 
The standard deviation of the local concentration of a metal in a bed of 
catalyst particles is calculated based on STEM determinations of local 
concentration on at least three, and preferably ten or more, samples from 
the bed. Samples are selected from the bed by techniques known to those of 
ordinary skill in the art and preferably examined by STEM as described 
hereinabove. The average and standard deviation of local concentration of 
metal are calculated from the individual measurements. The average metal 
content of the bed of catalyst particles also may be determined by other 
methods known in the art, and would be expected to approximate the average 
of local concentration in conformance with the standard deviation. "Bulk 
concentration" of metal, as used hereinafter, is characterized as the 
greater of the average of individual measurements of local concentration 
and the average concentration as determined by other methods known in the 
art. Homogeneous dispersion is defined as the ratio of the standard 
deviation to the bulk concentration of metal. 
Considering the refractory support utilized in the present invention, it is 
preferred that the material be a porous, adsorptive, high-surface area 
support having a surface area of about 25 to about 500 m.sup.2 /g. The 
porous carrier material should also be uniform in composition and 
relatively refractory to the conditions utilized in the hydrocarbon 
conversion process. By the terms "uniform in composition" it is meant that 
the support be unlayered, has no concentration gradients of the species 
inherent to its composition, and is completely homogeneous in composition. 
Thus, if the support is a mixture of two or more refractory materials, the 
relative amounts of these materials will be constant and uniform 
throughout the entire support. It is intended to include within the scope 
of the present invention carrier materials which have traditionally been 
utilized in dual-function hydrocarbon conversion catalysts such as: (1) 
refractory inorganic oxides such as alumina, titanium dioxide, zirconium 
dioxide, chromium oxide, zinc oxide, magnesia, thoria, boria, 
silica-alumina, silica-magnesia, chromia-alumina, alumina-boria, 
silica-zirconia, etc.; (2) ceramics, porcelain, bauxite; (3) silica or 
silica gel, silicon carbide, clays and silicates including those 
synthetically prepared and naturally occurring, which may or may not be 
acid treated, for example attapulgus clay, diatomaceous earth, fuller's 
earth, kaolin, kieselguhr, etc.; (4) crystalline zeolitic 
aluminosilicates, such as X-zeolite, Y-zeolite, mordenite, or L-zeolite, 
either in the hydrogen form or most preferably in nonacidic form with one 
or more alkali metals occupying the cationic exchangeable sites; (5) 
non-zeolitic molecular sieves, such as aluminophosphates or 
silico-aluminophosphates; and (6) combinations of one or more elements 
from one or more of these groups. 
The preferred refractory inorganic oxide for use in the present invention 
is alumina. Suitable alumina materials are the crystalline aluminas known 
as the gamma-, eta-, and theta-alumina, with gamma- or eta-alumina giving 
best results. The preferred refractory inorganic oxide will have an 
apparent bulk density of about 0.3 to about 1.0 g/cc and surface area 
characteristics such that the average pore diameter is about 20 to 300 
angstroms, the pore volume is about 0.1 to about 1 cc/g, and the surface 
area is about 100 to about 500 m.sup.2 /g. 
Although alumina is the preferred refractory inorganic oxide, a 
particularly preferred alumina is that which has been characterized in 
U.S. Pat. Nos. 3,852,190 and 4,012,313 as a by-product from a Ziegler 
higher alcohol synthesis reaction as described in Ziegler's U.S. Pat. No. 
2,892,858. For purposes of simplification, such an alumina will be 
hereinafter referred to as a "Ziegler alumina". Ziegler alumina is 
presently available from the Vista Chemical Company under the trademark 
"Catapal" or from Condea Chemie GmbH under the trademark "Pural." This 
material is an extremely high purity pseudoboehmite which, after 
calcination at a high temperature, has been shown to yield a high purity 
gamma-alumina. 
This alumina powder can be formed into any desired shape or type of carrier 
material known to those skilled in the art such as spheres, rods, pills, 
pellets, tablets, granules, extrudates, and like forms by methods well 
known to the practitioners of the catalyst material forming art. The 
preferred type of carrier material for the present invention is a 
cylindrical extrudate, preferably prepared by mixing the alumina powder 
with water and suitable peptizing agents until an extrudable dough is 
formed. The amount of water added to form the dough is typically 
sufficient to give a loss on ignition (LOI) at 500.degree. C. of about 45 
to 65 mass %, with a value of 55 mass % being preferred. The acid addition 
rate is generally sufficient to provide 2 to 7 mass % of the volatile-free 
alumina powder used in the mix, with a value of 3 to 4 mass % being 
preferred. 
In an especially preferred embodiment, the alumina powder is peptized with 
hydrochloric acid. Excellent results are obtained when the Group IVA(14) 
metal component is added as the chloride along with hydrogen chloride 
during the peptization step. Without limiting the invention, it is 
believed that the use of hydrochloric acid avoids subsequent hydrolysis of 
metal chloride during incorporation of the essential Group IVA(14) metal 
component into the catalyst composite. The resulting metal oxide polymer 
could result in localized concentration of the metal component, preventing 
the homogenized dispersion of the Group metal according to the present 
invention. Aluminum chloride or ammonium chloride are added during the 
mixing of the peptized alumina dough in an alternative embodiment. 
The resulting dough is extruded through a suitably sized die to form 
extrudate particles. These particles are then dried at a temperature of 
about 260.degree. to about 427.degree. C. for a period of about 0.1 to 5 
hours to form the preferred extrudate particles of the Ziegler alumina 
refractory inorganic oxide. It is preferred that the refractory inorganic 
oxide comprise substantially pure Ziegler alumina having an apparent bulk 
density of about 0.6 to about 1 g/cc and a surface area of about 150 to 
280 m.sup.2 /g (preferably 185 to 235 m.sup.2 /g, at a pore volume of 0.3 
to 0.8 cc/g). 
The homogeneously dispersed Group IVA(14) metal component is an essential 
ingredient of the catalyst of the present invention. Of the Group IVA(14) 
metals, germanium and tin are preferred and tin is especially preferred. 
This component may be present as an elemental metal, as a chemical 
compound such as the oxide, sulfide, halide, oxychloride, etc., or as a 
physical or chemical combination with the porous carrier material and/or 
other components of the catalytic composite. The Group IVA(14) metal 
component is preferably utilized in an amount sufficient to result in a 
final catalytic composite containing about 0.01 to about 5 mass % Group 
IVA(14) metal, calculated on an elemental basis, with best results 
obtained at a level of about 0.1 to about 2 mass % metal. 
The Group IVA(14) metal component may be incorporated in the catalytic 
composite in any suitable manner to achieve the homogeneous dispersion of 
the present invention, such as by coprecipitation with the porous carrier 
material, ion-exchange with the carrier material or impregnation of the 
carrier material at any stage in the preparation. One method of 
incorporating the Group IVA(14) metal component into the catalyst 
composite involves the utilization of a soluble, decomposable compound of 
a Group IVA(14) metal to impregnate and disperse the Group IVA(14) metal 
throughout the porous carrier material. The Group IVA(14) metal component 
can be impregnated either prior to, simultaneously with, or after the 
other components are added to the carrier material. Thus, the Group 
IVA(14) metal component may be added to the carrier material by 
commingling the latter with an aqueous solution of a suitable Group 
IVA(14) metal salt or soluble compound of Group IVA(14) metal such as 
stannous bromide, stannous chloride, stannic chloride, stannic chloride 
pentahydrate; or germanium oxide, germanium tetraethoxide, germanium 
tetrachloride; or lead nitrate, lead acetate, lead chlorate and the like 
compounds. The utilization of Group IVA(14) metal chloride compounds, such 
as stannic chloride, germanium tetrachloride or lead chlorate is 
particularly preferred since it facilitates the incorporation of both the 
Group IVA(14) metal component and at least a minor amount of the preferred 
halogen component in a single step. When combined with hydrogen chloride 
during the especially preferred alumina peptization step described 
hereinabove, a homogeneous dispersion of the Group IVA(14) metal component 
is obtained in accordance with the present invention. 
In an alternative embodiment, organic Group IVA(14) metal compounds are 
utilized to provide the homogeneous Group IVA(14) metal dispersion of the 
present invention. These organic Group IVA(14) metal compounds may be 
characterized by the formulas R.sub.4 Y, R.sub.3 YX, R.sub.2 YX.sub.2 and 
RYX.sub.3, wherein R represents an organic compound with from 1 to about 
10 carbon atoms, Y represents a Group IVA(14) metal, and X represents 
halide, hydroxide, or nitrate. Preferred compounds include trimethyltin 
chloride and dimethyltin dichloride. These organic Group IVA(14) metal 
compounds are preferably incorporated into the catalyst during the 
peptization of the inorganic oxide binder, and most preferably during 
peptization of alumina with hydrogen chloride or nitric acid. 
Another essential ingredient of the catalyst is a platinum-group-metal 
component. This comprises platinum, palladium, ruthenium, rhodium, 
iridium, osmium or mixtures thereof, with platinum being preferred. The 
platinum-group metal may exist within the final catalytic composite as a 
compound such as an oxide, sulfide, halide, oxyhalide, etc., in chemical 
combination with one or more of the other ingredients of the composite or 
as an elemental metal. Best results are obtained when substantially all of 
this component is present in the elemental state and it is homogeneously 
dispersed within the carrier material. This component may be present in 
the final catalyst composite in any amount which is catalytically 
effective, but relatively small amounts are preferred. In fact, the 
platinum-group metal generally will comprise about 0.01 to about 2 mass % 
of the final catalytic composite, calculated on an elemental basis. 
Excellent results are obtained when the catalyst contains about 0.05 to 
about 1 mass % of platinum. 
The platinum-group metal component may be incorporated in the porous 
carrier material in any suitable manner, such as coprecipitation, 
ion-exchange or impregnation. The preferred method of preparing the 
catalyst involves the utilization of a soluble, decomposable compound of 
platinum-group metal to impregnate the carrier material in a relatively 
uniform manner. For example, the component may be added to the support by 
commingling the latter with an aqueous solution of chloroplatinic or 
chloroiridic or chloropalladic acid. Other water-soluble compounds or 
complexes of platinum-group metals may be employed in impregnating 
solutions and include ammonium chloroplatinate, bromoplatinic acid, 
platinum trichloride, platinum tetrachloride hydrate, platinum 
dichlorocarbonyl dichloride, dinitrodiaminoplatinum, sodium 
tetranitroplatinate (II), palladium chloride, palladium nitrate, palladium 
sulfate, diamminepalladium (II) hydroxide, tetramminepalladium (II) 
chloride, hexamminerhodium chloride, rhodium carbonylchloride, rhodium 
trichloride hydrate, rhodium nitrate, sodium hexachlororhodate (III), 
sodium hexanitrorhodate (III), iridium tribromide, iridium dichloride, 
iridium tetrachloride, sodium hexanitroiridate (III), potassium or sodium 
chloroiridate, potassium rhodium oxalate, etc. The utilization of a 
platinum, iridium, rhodium, or palladium chloride compound, such as 
chloroplatinic, chloroiridic or chloropalladic acid or rhodium trichloride 
hydrate, is preferred since it facilitates the incorporation of both the 
platinum-group-metal component and at least a minor quantity of the 
preferred halogen component in a single step. Hydrogen chloride or the 
like acid is also generally added to the impregnation solution in order to 
further facilitate the incorporation of the halogen component and the 
uniform distribution of the metallic components throughout the carrier 
material. In addition, it is generally preferred to impregnate the carrier 
material after it has been calcined in order to minimize the risk of 
washing away the valuable platinum-group metal. 
In a preferred embodiment, the platinum-group metal is homogeneously 
dispersed in the catalyst. Homogeneous dispersion of the platinum-group 
metal is defined as the standard deviation relative to bulk concentration, 
based preferably upon ten or more determinations of metals concentration 
by STEM as described hereinabove. Without limiting the invention, it is 
believed that the homogeneous dispersion of the Group IVA(14) metal 
component and increased surface area effects homogeneous dispersion of the 
platinum-group metal. 
In an alternative embodiment, the catalyst comprises tin, platinum, and 
rhenium components. The rhenium component will be sufficient in this 
embodiment to result in a rhenium content of the finished catalyst of 
about 0.01 to 5 mass %. The rhenium component preferably is incorporated 
into the catalytic composite utilizing a soluble, decomposable rhenium 
compound. Rhenium compounds which may be employed include ammonium 
perrhenate, sodium perrhenate, potassium perrhenate, potassium rhenium 
oxychloride, potassium hexachlororhenate (IV), rhenium chloride, rhenium 
heptoxide, and the like compounds. Best results are obtained when an 
aqueous solution of perrhenic acid is employed in impregnation of the 
rhenium component. The platinum and rhenium components may be impregnated 
by use of separate impregnation solutions or, as is preferred, using a 
single impregnation solution comprising decomposable platinum and rhenium 
compounds. If two separate impregnation solutions are utilized in order to 
composite the platinum component and rhenium component with the refractory 
inorganic oxide, separate oxidation and reduction steps may be employed 
between application of the separate impregnation solutions. Additionally, 
halogen adjustment steps may be employed between application of the 
separate impregnation solutions. Such halogenation steps will facilitate 
incorporation of the catalytic components and halogen component into the 
refractory inorganic oxide. 
Indium is an alternative metal promoter of the tin-platinum-rhenium 
catalyst. The indium is incorporated into the catalyst composite by a 
second dispersion of an indium component over the first uniform dispersion 
of platinum component and rhenium component. The phrase "a second 
dispersion of indium component" describes a second application of indium 
component over the first dispersion of platinum and rhenium component, 
contacting the composite with indium in a manner which results in a 
dispersion thereof throughout the refractory inorganic oxide. At least one 
oxidation step is required prior to addition of the second dispersion of 
indium component. The indium component then may be added to the refractory 
inorganic oxide by commingling the later with an aqueous, acidic solution 
of suitable indium salt or suitable compound of indium such as indium 
tribromide, indium perchlorate, indium trichloride, indium trifluoride, 
indium nitrate, indium sulfate, and the like compounds. A particularly 
preferred impregnation solution comprises an acidic solution of indium 
trichloride. The total of the (rhenium+indium) components should comprise, 
on an elemental basis, from about 0.01 to about 5 mass % of the finished 
composite. 
Optionally the catalyst may also contain other components or mixtures 
thereof which act alone or in concert as catalyst modifiers to improve 
activity, selectivity or stability. Some known catalyst modifiers include 
cobalt, nickel, iron, tungsten, molybdenum, chromium, bismuth, antimony, 
zinc, cadmium and copper. Catalytically effective amounts of these 
components may be added in any suitable manner to the carrier material 
during or after its preparation or to the catalytic composite before, 
while or after other components are being incorporated. 
It is within the scope of the present invention that one or more of the 
metal components mentioned hereinbefore be a surface-layer component. 
Preferred surface-layer metal components comprise the platinum-group 
metals, cobalt, nickel and iridium. A metal component is considered to be 
a surface-layer component when he average content of the component in the 
exterior 50% of the exterior volume of the catalyst is at least 4 times 
the average concentration of the same metal component in the remaining 
interior portion of the catalyst A catalytic composite comprising a 
surface-layer metal component is described in U.S. Pat. No. 4,677,094, 
which is incorporated by reference into this specification. 
The surface-layer component may be incorporated into the catalytic 
composite in any suitable manner which results in the metal component 
being concentrated in the exterior surface of the catalyst support in the 
preferred manner. In addition, it may be added at any stage of the 
preparation of the composite--either during preparation of the carrier 
material or thereafter--and the precise method of incorporation used is 
not deemed to be critical so long as the resulting metal component is a 
surface-layer component as the term is used herein. A preferred way of 
incorporating this component is an impregnation step wherein the porous 
carrier material containing homogeneously dispersed Group IVA(14) metal is 
impregnated with a suitable metal-containing aqueous solution. It is also 
preferred that no "additional" acid compounds are to be added to the 
impregnation solution. 
An optional component of the catalyst, particularly useful in hydrocarbon 
conversion embodiments of the present invention comprising 
dehydrogenation, dehydrocyclization, or hydrogenation reactions, is an 
alkali or alkaline-earth metal component. More precisely, this optional 
ingredient is selected from the group consisting of the compounds of the 
alkali metals--cesium, rubidium, potassium sodium, and lithium--and the 
compounds of the alkaline earth metals--calcium, strontium, barium, and 
magnesium. Generally, good results are obtained in these embodiments when 
this component constitutes about 0.1 to about 5 mass % of the composite, 
calculated on an elemental basis. This optional alkali or alkaline earth 
metal component can be incorporated into the composite in any of the known 
ways with impregnation with an aqueous solution of a suitable 
water-soluble, decomposable compound being preferred. 
Another optional ingredient of the catalyst of the present invention is a 
Friedel-Crafts metal halide component. This ingredient is particularly 
useful in hydrocarbon conversion embodiments of the present invention 
wherein it is preferred that the catalyst utilized has a strong acid or 
cracking function associated therewith--for example, an embodiment wherein 
the hydrocarbons are to be hydrocracked or isomerized with the catalyst of 
the present invention. Suitable metal halides of the Friedel-Crafts type 
include aluminum chloride, aluminum bromide, ferric chloride, ferric 
bromide, zinc chloride, and the like compounds, with the aluminum halides 
and particularly aluminum chloride ordinarily yielding best results. 
Generally, this optional ingredient can be incorporated into the composite 
of the present invention by any of the conventional methods for adding 
metallic halides of this type and either prior to or after the adsorbed 
rhenium oxide reagent is added thereto; however, best results are 
ordinarily obtained when the metallic halide is sublimed onto the surface 
of the carrier material after rhenium is added thereto according to the 
preferred method disclosed in U.S. Pat. No. 2,999,074. The component can 
generally be utilized in any amount which is catalytically effective, with 
a value selected from the range of about 1 to about 15 mass % of the 
carrier material generally being preferred. An optional component of the 
Friedel-Crafts metal-halide-containing composite is a polyhalo selected 
from the group consisting of methylene halide, haloform, methylhaloform, 
carbon tetrahalide, sulfur dihalide, thionyl halide, and thiocarbonyl 
tetrahalide. Suitable polyhalo compounds thus include methylene chloride, 
chloroform, methylchloroform, carbon tetrachloride, and the like. In any 
case, the polyhalo compound must contain at least two chlorine atoms 
attached to the same carbon atom. Carbon tetrachloride is the preferred 
polyhalo compound. 
As heretofore indicated, it is necessary to employ at least one oxidation 
step in the preparation of the catalyst. The conditions employed to effect 
the oxidation step are selected to convert substantially all of the 
metallic components within the catalytic composite to their corresponding 
oxide form. The oxidation step typically takes place at a temperature of 
from about 370.degree. to about 600.degree. C. An oxygen atmosphere is 
employed typically comprising air. Generally, the oxidation step will be 
carried out for a period of from about 0.5 to about 10 hours or more, the 
exact period of time being that required to convert substantially all of 
the metallic components to their corresponding oxide form. This time will, 
of course, vary with the oxidation temperature employed and the oxygen 
content of the atmosphere employed. 
In addition to the oxidation step, a halogen adjustment step may also be 
employed in preparing the catalyst. As heretofore indicated, the halogen 
adjustment step may serve a dual function. First, the halogen adjustment 
step may aid in homogeneous dispersion of the Group IVA(14) metal 
component and the platinum-group metal component. Additionally, the 
halogen adjustment step can serve as a means of incorporating the desired 
level of halogen into the final catalytic composite. The halogen 
adjustment step employs a halogen or halogen-containing compound in air or 
an oxygen atmosphere. Since the preferred halogen for incorporation into 
the catalytic composite comprises chlorine, the preferred halogen or 
halogen-containing compound utilized during the halogen adjustment step is 
chlorine, HCl or precursor of these compounds. In carrying out the halogen 
adjustment step, the catalytic composite is contacted with the halogen or 
halogen-containing compound in air or an oxygen atmosphere at an elevated 
temperature of from abut 370.degree. to about 600.degree. C. It is further 
desired to have water present during the contacting step in order to aid 
in the adjustment. In particular, when the halogen component of the 
catalyst comprises chlorine, it is preferred to use a mole ratio of water 
to HCl of about 5:1 to about 100:1. The duration of the halogenation step 
is typically from about 0.5 to about 5 hours or more. Because of the 
similarity of conditions, the halogen adjustment step may take place 
during the oxidation step. Alternatively, the halogen adjustment step may 
be performed before or after the oxidation step as required by the 
particular method being employed to prepare the catalyst of the invention. 
Irrespective of the exact halogen adjustment step employed, the halogen 
content of the final catalyst should be such that there is sufficient 
halogen to comprise, on an elemental basis, from about 0.1 to about 10 
mass % of the finished composite. 
In preparing the catalyst, it is also necessary to employ a reduction step. 
The reduction step is designed to reduce substantially all of the 
platinum-group metal component to the corresponding elemental metallic 
state and to ensure a relatively uniform and finely divided dispersion of 
this component throughout the refractory inorganic oxide. It is preferred 
that the reduction step take place in a substantially water-free 
environment. Preferably, the reducing gas is substantially pure, dry 
hydrogen (i.e., less than 20 volume ppm water). However, other reducing 
gases may be employed such as CO.sub.2, nitrogen, etc. Typically, the 
reducing gas is contacted with the oxidized catalytic composite at 
conditions including a reduction temperature of from about 315.degree. to 
about 650.degree. C. for a period of time of from about 0.5 to 10 or more 
hours effective to reduce substantially all of the platinum-group metal 
component to the elemental metallic state. The reduction step may be 
performed prior to loading the catalytic composite into the hydrocarbon 
conversion zone or it may be performed in situ as part of a hydrocarbon 
conversion process start-up procedure. However, if this latter technique 
is employed, proper precautions must be taken to predry the hydrocarbon 
conversion plant to a substantially water-free state and a substantially 
water-free hydrogen-containing reduction gas should be employed. 
The catalytic composite may be beneficially subjected to a presulfiding 
step designed to incorporate sufficient sulfur to comprise, on an 
elemental basis, from about 0.05 to about 0.5 mass % of the finished 
composite. The sulfur component may be incorporated into the catalyst by 
any known technique. For example, the catalytic composite may be subjected 
to a treatment which takes place in the presence of hydrogen in a suitable 
sulfur-containing compound such as hydrogen sulfide, lower molecular 
weight mercaptans, organic sulfides, disulfides, etc. Typically, this 
procedure comprises treating the reduced catalyst with a sulfiding gas 
such as a mixture of hydrogen and hydrogen sulfide having about 10 moles 
of hydrogen per mole of hydrogen sulfide at conditions sufficient to 
effect the desired incorporation of sulfur, generally including a 
temperature ranging from about 10.degree. up to about 600.degree. C. or 
more. It is generally a good practice to perform this sulfiding step under 
substantially water-free conditions. 
The catalyst of the present invention has particular utility as a 
hydrocarbon conversion catalyst. The hydrocarbon which is to be converted 
is contacted with the catalyst at hydrocarbon conversion conditions, which 
include a temperature of from 40.degree. to 300.degree. C., a pressure of 
from atmospheric to 200 atmospheres absolute and liquid hourly space 
velocities from about 0.1 to 100 hr.sup.-1. 
In the preferred catalytic reforming embodiment, hydrocarbon feedstock and 
a hydrogen-rich gas are preheated and charged to a reforming zone 
containing typically two to five reactors in series. Suitable heating 
means are provided between reactors to compensate for the net endothermic 
heat of reaction in each of the reactors. The reactants may contact the 
catalyst in individual reactors in either upflow, downflow, or radial flow 
fashion, with the radial flow mode being preferred. The catalyst is 
contained in a fixed-bed system or a moving-bed system with associated 
continuous catalyst regeneration. The preferred embodiment of the current 
invention is a fixed-bed system. Alternative approaches to reactivation of 
deactivated catalyst are well known to those skilled in the art, and 
include semiregenerative operation in which the entire unit is shut down 
for catalyst regeneration and reactivation or swing-reactor operation in 
which an individual reactor is isolated from the system, regenerated and 
reactivated while the other reactors remain on-stream. 
Effluent from the reforming zone is passed through a cooling means to a 
separation zone, typically maintained at about 0.degree. to 65.degree. C., 
wherein a hydrogen-rich gas is separated from a liquid stream commonly 
called "unstabilized reformate". The resultant hydrogen stream can then be 
recycled through suitable compressing means back to the reforming zone. 
The liquid phase from the separation zone is typically withdrawn and 
processed in a fractionating system in order to adjust the butane 
concentration, thereby controlling front-end volatility of the resulting 
reformate. 
Operating conditions applied in the reforming process of the present 
invention include a pressure selected within the range of atmospheric to 
70 atmospheres (abs), with the preferred pressure being about 3 to 40 
atmospheres (abs). Particularly good results are obtained at low pressure, 
namely a pressure of about 3 to 25 atmospheres (abs). Reforming 
temperature is in the range from about 315.degree. to 600.degree. C., and 
preferably from about 425.degree. to 565.degree. C. As is well known to 
those skilled in the reforming art, the initial selection of the 
temperature within this broad range is made primarily as a function of the 
desired octane of the product reformate considering the characteristics of 
the charge stock and of the catalyst. Ordinarily, the temperature then is 
thereafter slowly increased during the run to compensate for the 
inevitable deactivation that occurs to provide a constant octane product. 
Sufficient hydrogen is supplied to provide an amount of about 1 to about 
20 moles of hydrogen per mole of hydrocarbon feed entering the reforming 
zone, with excellent results being obtained when about 2 to about 10 moles 
of hydrogen are used per mole of hydrocarbon feed. Likewise, the liquid 
hourly space velocity (LHSV) used in reforming is selected from the range 
of about 0.1 to about 10 hr.sup.-1, with a value in the range of about 1 
to about 5 hr.sup.-1 being preferred. 
The hydrocarbon feed stream that is charged to this reforming system will 
comprise naphthenes and paraffins that boil within the gasoline range. The 
preferred charge stocks are naphthas consisting principally of naphthenes 
and paraffins, although, in many cases, aromatics also will be present. 
This preferred class includes straight-run gasolines, natural gasolines, 
synthetic gasolines, and the like. As an alternative embodiment, it is 
frequently advantageous to charge thermally or catalytically cracked 
gasolines or partially reformed naphthas. Mixtures of straight-run and 
cracked gasoline-range naphthas can also be used to advantage. The 
gasoline-range naphtha charge stock may be a full-boiling gasoline having 
an initial boiling point of from about 40.degree.-70.degree. C. and an end 
boiling point within the range of from about 160.degree.-220.degree. C., 
or may be a selected fraction thereof which generally will be a 
higher-boiling fraction commonly referred to as a heavy naphtha--for 
example, a naphtha boiling in the range of 100.degree.-200.degree. C. In 
some cases, it is also advantageous to charge pure hydrocarbons or 
mixtures of hydrocarbons that have been recovered from extraction 
units--for example, raffinates from aromatics extraction or straight-chain 
paraffins--which are to be converted to aromatics. 
It is generally preferred to utilize the present invention in a 
substantially water-free environment. Essential to the achievement of this 
condition in the reforming zone is the control of the water level present 
in the charge stock and the hydrogen stream which is being charged to the 
zone. Best results are ordinarily obtained when the total amount of water 
entering the conversion zone from any source is held to a level less than 
50 ppm and preferably less than 20 ppm, expressed as weight of equivalent 
water in the charge stock. In general, this can be accomplished by careful 
control of the water present in the charge stock and in the hydrogen 
stream. The charge stock can be dried by using any suitable drying means 
known to the art such as a conventional solid adsorbent having a high 
selectivity for water; for instance, sodium or calcium crystalline 
aluminosilicates, silica gel, activated alumina, molecular sieves, 
anhydrous calcium sulfate, high surface area sodium, and the like 
adsorbents. Similarly, the water content of the charge stock may be 
adjusted by suitable stripping operations in a fractionation column or 
like device. In some cases, a combination of adsorbent drying and 
distillation drying may be used advantageously to effect almost complete 
removal of water from the charge stock. Preferably, the charge stock is 
dried to a level corresponding to less than 20 ppm of H.sub.2 O 
equivalent. 
It is preferred to maintain the water content of the hydrogen stream 
entering the hydrocarbon conversion zone at a level of about 10 to about 
20 volume ppm or less. In the cases where the water content of the 
hydrogen stream is above this range, this can be conveniently accomplished 
by contacting the hydrogen stream with a suitable desiccant such as those 
mentioned above at conventional drying conditions. 
It is a preferred practice to use the present invention in a substantially 
sulfur-free environment. Any control means known in the art may be used to 
treat the hydrocarbon feedstock which is to be charged to the reforming 
reaction zone. For example, the feedstock may be subjected to adsorption 
processes, catalytic processes, or combinations thereof. Adsorption 
processes may employ molecular sieves, high surface area silica-aluminas, 
carbon molecular sieves, crystalline aluminosilicates, activated carbons, 
high surface area metallic containing compositions, such as nickel or 
copper and the like. It is preferred that these charge stocks be treated 
by conventional catalytic pretreatment methods such as hydrorefining, 
hydrotreating, hydrodesulfurization, etc., to remove substantially all 
sulfurous, nitrogenous and water-yielding contaminants therefrom, and to 
saturate any olefins that may be contained therein. Catalytic processes 
may employ traditional sulfur reducing catalyst formulations known to the 
art including refractory inorganic oxide supports containing metals 
selected from the group comprising Group VI-B(6), Group II-B(12), and 
Group VIII(8-10) of the Periodic Table. 
One embodiment of the invention involves the process of converting a 
hydrocarbon charge stock at catalytic dehydrocyclization conditions. In 
particular, the preferred hydrocarbon charge stock comprises C.sub.6 
-C.sub.8 nonaromatic hydrocarbons. Dehydrocyclization conditions include a 
pressure of from about atmospheric to 40 atmosphere (abs), with the 
preferred pressure being from about 2 to 15 atmospheres (abs), a 
temperature of from about 350.degree. to 650.degree. C., and a liquid 
hourly space velocity of from about 0.1 to about 10 hr.sup.-1. Preferably, 
hydrogen may be employed as a diluent. When present, hydrogen may be 
circulated at a rate of from about 0.2 to about 10 moles of hydrogen per 
mole of charge stock hydrocarbon. 
It is preferred that the charge stock of the alternative dehydrocyclization 
process embodiment substantially comprises paraffins, as the purpose of a 
dehydrocyclization process is to convert paraffins to aromatics. Because 
of the high value of C.sub.6 -C.sub.8 aromatics, it is additionally 
preferred that the hydrocarbon charge stock comprise C.sub.6 -C.sub.8 
paraffins. However, notwithstanding this preference, the hydrocarbon 
charge stock may comprise naphthenes, aromatics, and olefins in addition 
to C.sub.6 -C.sub.8 paraffins. 
In an alternative embodiment of the invention, dehydrogenatable 
hydrocarbons are contacted with the catalytic composite of the present 
invention in a dehydrogenation zone maintained at dehydrogenation 
conditions. This contacting may be accomplished in a fixed-catalyst bed 
system, a moving-catalyst-bed system, a fluidized-bed system, etc., or in 
a batch-type operation. A fixed-bed system is preferred. The hydrocarbon 
may be contacted with the catalyst bed in either upward, downward or 
radial-flow fashion. Radial flow of the hydrocarbon through the catalyst 
bed is preferred for commercial-scale reactors. The hydrocarbon may be in 
the liquid phase, a mixed vapor-liquid phase or the vapor phase when it 
contacts the catalyst. Preferably, it is in the vapor phase. 
Dehydrogenation conditions include a pressure of from about 0.01 to 10 
atmospheres (abs), a temperature of from about 400.degree. to 900.degree. 
C. and a liquid hourly space velocity of from about 0.1 to 100 hr.sup.-1. 
The pressure is maintained as low as practicable, consistent with 
equipment limitations, to take advantage of chemical equilibrium. Required 
temperature, for comparable conversion, generally is higher for 
lower-molecular-weight normal paraffins. 
Hydrocarbons which may be dehydrogenated comprise dehydrogenatable 
hydrocarbons having from 2 to 30 or more carbon atoms including paraffins, 
alkylaromatics, naphthenes and olefins. One group of hydrocarbons which 
can be dehydrogenated with the catalyst is the group of normal paraffins 
having from 2 to 30 or more carbon atoms. The catalyst is particularly 
useful for dehydrogenating paraffins having from 2 to 25 or more carbon 
atoms to the corresponding monoolefins or for dehydrogenating monoolefins 
having from 3 to 15 or more carbon atoms to the corresponding diolefins. 
In yet another alternative embodiment of the present invention, an 
isomerizable hydrocarbon charge stock, preferably in admixture with 
hydrogen, is contacted with a catalyst of the type hereinbefore described 
in a hydrocarbon isomerization zone. Contacting may be effected using the 
catalyst in a fixed-bed system, a moving-bed system, a fluidized-bed 
system, or in a batch-type operation. In view of the danger of attrition 
loss of the valuable catalyst and of operational advantages, it is 
preferred to use a fixed-bed system. The conversion zone may be in a 
single reactor or in two or more separate reactors with suitable means 
therebetween to insure that the desired isomerization temperature is 
maintained at the entrance to each zone. Two or more reactors in sequence 
are preferred to enable improved isomerization through control of 
individual reactor temperatures and for partial catalyst replacement 
without a process shutdown. The reactants may be contacted with the 
catalyst bed in either upward, downward, or radial flow fashion. The 
reactants may be in a the liquid phase, a mixed liquid-vapor phase, or a 
vapor phase when contacted with the catalyst, with excellent results being 
obtained by application of the present invention to a primarily 
liquid-phase operation. 
Isomerization reactor temperatures will usually range from about 40.degree. 
to 250.degree. C. Lower reaction temperatures are generally preferred 
since the equilibrium favors higher concentration of isoalkanes relative 
to normal alkanes. When the feed mixture is primarily C.sub.5 and C.sub.6 
alkanes temperatures in the range of from about 40.degree. to about 
150.degree. C. are preferred. When it is desired to isomerize significant 
amounts of butanes, higher reaction temperatures in the range from about 
145.degree. to 225.degree. C. are required to maintain catalyst activity. 
Reactor operating pressures generally range from about atmospheric to 100 
atmospheres (abs), with preferred pressures in the range of from 20 to 35 
atmospheres (abs). Liquid hourly space velocities range from about 0.25 to 
about 12 volumes of isomerizable hydrocarbon feed per hour per volume of 
catalyst, with a range of about 0.5 to 5 hr.sup.-1 being preferred. The 
mol ratio of hydrogen to hydrocarbon feed is from about 0.01 to 5, with a 
mol ratio of 0.05 or less being preferred. The isomerization process also 
requires the presence of a small amount of an organic chloride promoter 
amounting to from 30 to 300 mass ppm of the combined feed. 
Alkanes having 4 to 7 carbon atoms per molecule (C.sub.4 -C.sub.7) are 
preferred isomerization feedstocks. These may be contained in such streams 
from petroleum refining or synthetic-fuel production as light straight-run 
naphtha, light natural gasoline, light reformate, light raffinate from 
aromatics extraction, light cracked naphtha, normal-butane concentrate, 
field butanes and the like. An especially preferred feedstock is light 
straight-run naphtha, containing more than 50% of C.sub.5 and C.sub.6 
paraffins with a high concentration of low-octane normal paraffins; this 
feedstock is particularly susceptible to octane-number upgrading by 
isomerization. The light straight-run naphtha and other feedstocks also 
may contain naphthenes, aromatics, olefins, and hydrocarbons heavier than 
C.sub.6. The olefin content should be limited to a maximum of 10% and the 
content of hydrocarbons heavier than C.sub.6 to 20% for effective control 
of hydrogen consumption, cracking reactions, heat of reaction and catalyst 
activity. It is generally known that high-chloride platinum-alumina 
catalysts of this type are highly sensitive to sulfur- and 
oxygen-containing compounds. The feedstock therefore must be relatively 
free of such compounds, with a sulfur concentration generally no greater 
than 0.5 ppm. 
As discussed previously, three parameters are especially useful in 
evaluating hydrocarbon-conversion process and catalyst performance. 
"Activity" is a measure of the catalyst's ability to convert reactants at 
a specified set of reaction condition, specifically temperature in the 
present embodiment. "Selectivity" is an indication of the catalyst's 
ability to produce a high yield of the desired product, specifically 
C.sub.5 + reformate in the present embodiment. "Stability" is a measure of 
the catalyst's ability to maintain its activity and selectivity over time. 
The following examples are presented to elucidate the catalyst and process 
of the present invention, demonstrating selectivity and activity 
advantages over prior-art technology. These examples are offered as 
illustrative embodiments and should not be interpreted as limiting the 
claims. 
EXAMPLE I 
A first extruded catalyst having a diameter of about 2.1 mm was prepared in 
order to exemplify the catalyst of the present invention and designated as 
Catalyst A. Substantially pure pseudoboehmite powder was charged to a 
continuous mixer in the amount of 1000 grams along with 723 grams of a 
solution of hydrogen chloride, stannic chloride and aluminum chloride. The 
resulting dough had a moisture content of about 57%. The dough was mixed 
for 10 minutes and extruded through a 1/12" die to form cylindrical 
extrudates. The extrudates were dried for 2 hours and calcined at 
610.degree. C. for 2 hours. 
The calcined extrudates then were added to an impregnation solution 
containing chloroplatinic acid and hydrogen chloride sufficient to result 
in a final composite containing, on an elemental basis, about 0.37% 
platinum. The impregnation solution was evaporated and the resulting 
particles were contacted with an air stream containing H.sub.2 O and HCl 
sufficient to adjust the chloride content of the finished catalyst to 
about 1%. The oxidized and chloride-adjusted particles then were oxidized 
and reduced in a conventional manner to yield a catalyst having the 
following approximate composition in mass %: 
______________________________________ 
Tin 0.23 
Platinum 0.37 
Chlorine 1.04 
Alumina Balance 
______________________________________ 
EXAMPLE II 
A control catalyst having a diameter of about 2.1 mm was prepared in order 
to contrast the prior art with the present invention and designated as 
Catalyst B. Substantially pure pseudoboehmite powder was charged to a 
continuous mixer in the amount of 1000 grams along with 670 grams of a 
solution of nitric acid and stannic chloride. The formation of a 
precipitate of stannic oxide prior to mixing was noted. The resulting 
dough had a moisture content of about 57%. The dough was mixed for 10 
minutes and extruded through a 1/12" die to form cylindrical extrudates. 
The extrudates were dried, calcined, subjected to platinum impregnation 
and chloride adjustment, oxidized and reduced in the manner of Catalyst A 
to yield a catalyst having the following approximate composition in mass 
%: 
______________________________________ 
Tin 0.24 
Platinum 0.37 
Chlorine 0.98 
Alumina Balance 
______________________________________ 
EXAMPLE III 
The 2.1 mm Catalysts A and B of the invention and of the prior art, 
respectively, were examined by STEM to determine the extent of dispersion 
of the tin and platinum components. The catalysts were ground and a 
carbon-coated copper grid prewet with isopropanol was dipped in the 
powder, allowed to dry and inserted into the VG-HB-5 dedicated STEM. 
Results were as follows: 
______________________________________ 
Catalyst A 
Catalyst B 
Tin; Invention Prior Art 
______________________________________ 
Number of readings 14 27 
Mean, mass % 0.21 0.33 
Standard deviation 0.04 0.12 
Platinum: 
Number of readings 14 27 
Mean, mass % 0.35 0.38 
Standard deviation, mass % 
0.08 0.21 
______________________________________ 
The comparative results are illustrated in FIG. 1. 
EXAMPLE IV 
Pilot-plant tests were structured to compare the selectivity and activity 
of the catalysts of the invention and of the prior art in a reforming 
process. Two tests were performed on the catalyst of the invention and one 
on the prior art catalyst. The feedstock for the comparative tests was a 
hydrotreated petroleum-derived naphtha having the following 
characteristics: 
______________________________________ 
Sp. gr. 
______________________________________ 
0.746 
ASTM D-86, .degree.C.: 
IBP 85 
50% 134 
EP 194 
Mass %: Paraffins 64.5 
Naphthenes 
23.0 
Aromatics 12.5 
______________________________________ 
Each test was based on a severity of 98 RON (Research Octane Number) clear 
C.sub.5 + product at a pressure of 17 atmospheres (ga) and a liquid hourly 
space velocity of 2.5 hr.sup.-1. 
Comparative selectivities and activities are shown in FIG. 2. Selectivity 
is expressed as volume % yield of C.sub.5 + product. Activity is expressed 
as the temperature requirement to produce a 98 RON clear product. The 
catalyst of the invention demonstrated an average selectivity advantage of 
about 0.6% and an activity advantage of about 3.degree. C. over the 
catalyst of the prior art. 
EXAMPLE V 
An extruded catalyst having a diameter of about 1.6 mm was prepared in 
order to further exemplify the catalyst of the present invention and 
designated as Catalyst C. Substantially pure pseudoboehmite powder was 
charged to a continuous mixer in the amount of 1000 grams along with 723 
grams of a solution of hydrogen chloride, stannic chloride and aluminum 
chloride. The resulting dough had a moisture content of about 57%. The 
dough was mixed for 10 minutes and extruded through a 1/16" die to form 
cylindrical extrudates. The extrudates were dried, calcined, subjected to 
platinum impregnation and chloride adjustment, oxidized and reduced in the 
manner of Catalyst A to yield a catalyst having the following approximate 
composition in mass %: PG,27 
______________________________________ 
Tin 0.227 
Platinum 
0.356 
Chlorine 
1.06 
Alumina 
Balance 
______________________________________ 
EXAMPLE VI 
A control catalyst having a diameter of about 1.6 mm was prepared in order 
to contrast the prior art with the present invention and designated as 
Catalyst D. Substantially pure pseudoboehmite powder was charged to a 
continuous mixer in the amount of 1000 grams along with 670 grams of a 
solution of nitric acid and stannic chloride. The formation of a 
precipitate of stannic oxide prior to mixing was noted. The resulting 
dough had a moisture content of about 57%. The dough was mixed for 10 
minutes and extruded through a 1/16" die to form cylindrical extrudates. 
The extrudates were dried, calcined, subjected to platinum impregnation 
and chloride adjustment, oxidized and reduced in the manner of Catalyst A 
to yield a catalyst having the following approximate composition in mass 
%: 
______________________________________ 
Tin 0.22 
Platinum 
0.36 
Chlorine 
1.02 
Alumina 
Balance 
______________________________________ 
EXAMPLE VII 
The 1.6 mm catalysts of the invention and of the prior art, respectively, 
were examined by STEM to determine the extent of dispersion of the tin and 
platinum components. The catalysts were ground and a carbon-coated copper 
grid prewet with isopropanol was dipped in the powder, allowed to dry and 
inserted into the VG-HB-5 dedicated STEM. Results were as follows: 
______________________________________ 
Catalyst C 
Catalyst D 
Invention 
Prior Art 
______________________________________ 
Tin: 
Number of readings 17 12 
Mean, mass % 0.22 0.24 
Standard deviation 0.04 0.07 
Platinum: 
Number of readings 17 12 
Mean, mass % 0.42 0.39 
Standard deviation, mass % 
0.10 0.14 
______________________________________ 
The comparative results are illustrated in FIG. 3. 
EXAMPLE VIII 
Pilot-plant tests were structured to compare the selectivity and activity 
of Catalysts C and D of the invention and of the prior art in a reforming 
process. The feedstock for the comparative tests was a hydrotreated 
petroleum-derived naphtha having the same characteristics as in Example 
IV. Each test was based on a severity of 98 RON (Research Octane Number) 
clear C.sub.5 + product at a pressure of 17 atmospheres (ga) and a liquid 
hourly space velocity of 2.5 hr.sup.-1. 
Comparative selectivities and activities are shown in FIG. 4. Selectivity 
is expressed as volume % yield of C.sub.5 + product. Activity is expressed 
as the temperature requirement to produce a 98 RON clear product. The 
catalyst of the invention demonstrated a selectivity advantage of about 
0.4 to 0.5% over the catalyst of the prior art. Activities of the two 
catalysts were comparable within reproducibility limits. 
EXAMPLE IX 
Two catalysts were prepared to determine the effect of the homogeneity of 
germanium dispersion on catalyst performance. 
Catalyst E was prepared commencing with the combination of substantially 
pure pseudoboehmite powder in a continuous mixer in the amount of 1000 
grams with 670 grams of a solution of hydrogen chloride, germanium 
chloride and aluminum chloride. The formation of a precipitate of 
germanium oxide prior to mixing was noted. The resulting dough had a 
moisture content of about 57%. The dough was mixed for 10 minutes and 
extruded through a 1/12" die to form cylindrical extrudates. The 
extrudates were dried, calcined, subjected to platinum impregnation and 
chloride adjustment, oxidized and reduced in the manner of Catalyst A to 
yield a catalyst having the following approximate composition in mass %. 
______________________________________ 
Germanium 
0.24 
Platinum 
0.37 
Chlorine 
0.98 
Alumina Balance 
______________________________________ 
Catalyst F was prepared commencing with the combination of substantially 
pure pseudoboehmite powder in a continuous mixer in the amount of 1000 
grams with 670 grams of a solution of nitric acid and germanium chloride. 
The resulting dough had a moisture content of about 57%. The dough was 
mixed for 10 minutes and extruded through a 1/12" die to form cylindrical 
extrudates. The extrudates were dried, calcined, subjected to platinum 
impregnation and chloride adjustment, oxidized and reduced in the manner 
of Catalyst A to yield a catalyst having the following approximate 
composition in mass %: 
______________________________________ 
Germanium 
0.24 
Platinum 
0.37 
Chlorine 
0.98 
Alumina Balance 
______________________________________ 
EXAMPLE X 
The 2.1 mm Catalysts F and E of the invention and of the prior art, 
respectively, were examined by STEM to determine the extent of dispersion 
of the tin and platinum components. The catalysts were ground and a 
carbon-coated copper grid prewet with isopropanol was dipped in the 
powder, allowed to dry and inserted into the VG-HB-5 dedicated STEM. 
Results were as follows: 
______________________________________ 
Catalyst E 
Catalyst F 
______________________________________ 
Germanium: 
Number of readings 15 14 
Mean, mass % 0.255 0.21 
Standard deviation 0.06 0.03 
Platinum: 
Number of readings 15 14 
Mean, mass % 0.34 0.29 
Standard deviation, mass % 
0.13 0.10 
______________________________________ 
EXAMPLE XI 
Pilot-plant tests were structured to compare the selectivity and activity 
of Catalysts E and F in a reforming process. The feedstock for the 
comparative tests was a hydrotreated petroleum-derived naphtha having the 
same characteristics as in Example IV. Each test was based on a severity 
of 98 RON (Research Octane Number) clear C.sub.5 + product at a pressure 
of 17 atmospheres (ga) and a liquid hourly space velocity of 2.5 
hr.sup.-1. 
Relative selectivity, activity and stability are compared below. 
Selectivity is expressed as volume % yield of C.sub.5 + product. Activity 
is expressed as the temperature requirement to produce a 98 RON clear 
product. Stability is expressed as the required increase in temperature 
requirement per volume of the feed. Results are: 
______________________________________ 
Catalyst E 
Catalyst F 
______________________________________ 
Standard deviation of Ge. % 
24 14 
Selectivity, Vol. %, C.sub.5 + 
base base + 0.9% 
Activity, .degree.C. 
base base-7.degree. C. 
Stability, .degree.C./Vol 
base 0.7 base 
______________________________________ 
Catalyst F, having germanium more homogeneously dispersed than in Catalyst 
E, is superior in selectivity, activity and stability.