U.S. patent application number 09/969054 was filed with the patent office on 2002-03-28 for hydrogenation catalysts.
This patent application is currently assigned to Sud-Chemie Inc.. Invention is credited to Faris, William M., Hopkins, P. Donald, Huang, Dinah C., Jerus, Paul.
Application Number | 20020038065 09/969054 |
Document ID | / |
Family ID | 23426012 |
Filed Date | 2002-03-28 |
United States Patent
Application |
20020038065 |
Kind Code |
A1 |
Huang, Dinah C. ; et
al. |
March 28, 2002 |
Hydrogenation catalysts
Abstract
A hydrogenation catalyst which is sulfur tolerant and which
includes from about 0.1 to about 1 percent platinum by weight and
from 0.2 to about 2 percent by weight palladium on a predominantly
theta alumina carrier. Also disclosed is a process for the
manufacture and use of the hydrogenation catalyst.
Inventors: |
Huang, Dinah C.; (Prospect,
KY) ; Faris, William M.; (Louisville, KY) ;
Hopkins, P. Donald; (Louisville, KY) ; Jerus,
Paul; (Prospect, KY) |
Correspondence
Address: |
Scott R. Cox
400 West Market St., Suite 2200
Louisville
KY
40202
US
|
Assignee: |
Sud-Chemie Inc.
Louisville
KY
|
Family ID: |
23426012 |
Appl. No.: |
09/969054 |
Filed: |
October 2, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09969054 |
Oct 2, 2001 |
|
|
|
09362408 |
Jul 28, 1999 |
|
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Current U.S.
Class: |
585/266 ;
208/143; 208/144; 585/250; 585/259; 585/275 |
Current CPC
Class: |
B01J 23/44 20130101;
C10G 45/52 20130101 |
Class at
Publication: |
585/266 ;
585/275; 585/250; 585/259; 208/143; 208/144 |
International
Class: |
C07C 005/02; C07C
005/03; C07C 005/10 |
Claims
1. A process for hydrogenation of an aromatic feed stream
containing sulfur comprising passing the aromatic feed stream over
a hydrogenation catalyst comprising from about 100 ppm to about 5.0
percent by weight of each of platinum and palladium and an inert
alumina carrier, wherein the alumina carrier comprises at least
about 50 percent, by weight, of a theta or delta alumina wherein
the surface area of the theta or delta alumina carrier is from 60
to about 100 m.sup.2/g.
2. The process of claim 1 wherein the sulfur comprises less than
about 150 ppm by weight of the feed stream.
3. The process of claim 1 wherein the aromatic feed stream is
predominantly benzene.
4. A process for hydrogenation of a diolefin feed stream containing
sulfur, comprising passing the feed stream over a hydrogenation
catalyst comprising from about 100 ppm to about 5.0 percent by
weight of each of platinum and palladium and an inert alumina
carrier, wherein the alumina carrier comprises at least about 50
percent, by weight, of a theta or delta alumina wherein the surface
area of the theta or delta alumina carrier is from 60 to about 100
m.sup.2/g.
5. The process of claim 4 wherein the alumina carrier comprises at
least about 60 percent by weight of a theta or delta alumina.
6. The process of claim 1 wherein the alumina carrier comprises
from about 1 to about 40 percent by weight of an alpha alumina.
7. The process of claim 1 wherein the weight of platinum comprises
from about 0.1 to about 1.0 percent by weight of the catalyst.
8. The process of claim 1 wherein the weight of palladium comprises
from about 0.2 to about 2.0 percent by weight of the catalyst.
9. The process of claim 1 wherein the weight of platinum comprises
from about 0.1 to about 1.0 percent by weight and the weight of
palladium is from about 0.2 to about 2.0 percent by weight of the
catalyst.
10. The process of claim 1 wherein the catalyst further comprises
from about 0.1 to about 2 percent by weight of chloride.
11. The process of claim 1 wherein the molar ratio of the platinum
to the palladium on a mole ratio basis in the catalyst is from
about 1 to 3 to about 1 to 9.
12. The process of claim 1 wherein the molar ratio of the platinum
to the palladium on a mole ratio basis in the catalyst is from
about 1 to 4 to about 1 to 7.
13. The process of claim 1 wherein the catalyst is sulfur
tolerant.
14. The process of claim 1 wherein the catalyst has a pore volume
of from about 0.3 to about 0.7 cc/g.
Description
RELATED APPLICATIONS
[0001] This is a divisional application of application Ser. No.
09/362,408, filed Jul. 28, 1999.
BACKGROUND OF INVENTION
[0002] The field to which this invention pertains is hydrogenation
catalysts, and more particularly, sulfur tolerant, aromatic
hydrogenation catalysts and a process for their use.
DESCRIPTION OF THE RELATED ART
[0003] There is today a significant need in the petroleum industry
for non-aromatic solvents, including liquid hydrocarbons which boil
in the range of about 200 to 1100.degree. F. Such products include,
for example, aviation turbine fuel, diesel fuel, solvents, white
oil, lube oil and the like. Products in this boiling range are
conventionally produced by the hydrotreating and/or hydrocracking
of various refinery feed streams, boiling in and above the desired
product range. While hydrotreating and hydrocracking operations
generally affect substantial partial hydrogenation of polynuclear
aromatics, the resulting products still contain a relatively high
percentage of monoaromatic hydrocarbons and a substantial amount of
sulfur. Further hydrogenation of these products is desired in many
cases to produce acceptable solvent products and to meet
specifications for jet fuels and other such final products.
[0004] Other conventional hydrogenation applications include the
hydrogenation of benzene to cyclohexane. One process for the
production of cyclohexane comprises contacting a mixture of
benzene, cyclohexane and hydrogen under hydrogenation conditions in
the presence of a Group VI and Group VIII metal hydrogenation
catalyst, such as is disclosed in U.S. Pat. No. 3,622,645. See also
U.S. Pat. No. 3,869,521 which discloses a transition metal catalyst
useful for the conversion of benzene to cyclohexane.
[0005] The hydrogenation of unsaturated hydrocarbons, particularly
aromatic hydrocarbons, to corresponding saturated hydrocarbons
using platinum and/or palladium catalysts is disclosed in U.S. Pat.
No. 3,637,484. In this patent, platinum and/or palladium are
deposited selectively by cationic exchange upon a silica/alumina
co-gel or copolymer, which in turn is dispersed in a large pore
alumina gel matrix.
[0006] U.S. Pat. No. 3,674,888 discloses a process for selectively
hydrogenating unsaturated hydrocarbons in their liquid phase
utilizing palladium on an alumina catalyst. The catalyst is the
product resulting from contacting alumina agglomerates of a
specific surface area with steam, admixing the agglomerate with a
palladium compound and calcining the resulting mixture.
[0007] A significant problem that can occur with platinum and/or
palladium catalysts is that they can be poisoned by sulfur
compounds that may be present in the feed stream. A platinum and
palladium catalyst for the selective hydrogenation of aromatics and
olefins with some tolerance for sulfur and nitrogen is disclosed in
U.S. Pat. Nos. 4,049,576 and 3,943,053. These patents teach a
catalyst containing from 0.2 to 1 percent by weight of each of
platinum and palladium impregnated on an inert carrier, preferably
a high surface area, gamma alumina.
[0008] Another high surface area gamma alumina-based catalyst
useful for the hydrogenation of unsaturated hydrocarbons is
disclosed by U.S. Pat. No. 3,674,888. Other high surface area
catalysts, preferably using a gamma alumina carrier, are disclosed
in U.S. Pat. No. 4,713,363. See also U.S. Pat. No. 4,952,549.
[0009] In addition to alumina-based carriers, silica-alumina
carriers onto which noble metals, such as platinum or palladium,
are impregnated for the hydrogenation of petroleum feed streams are
disclosed, for example, in U.S. Pat. No. 3,637,484. A catalyst with
sulfur tolerance for the hydrogenation of aromatics, wherein the
carrier comprises a surface-modified alumina/silica support, onto
which noble metals have been impregnated, is disclosed in WO
98/35754. See also U.S. Pat. Nos. 3,461,181, 3,859,370 and
4,251,392.
[0010] Other catalyst containing palladium and/or platinum secured
on inert alumina and/or silica carriers are disclosed in U.S. Pat.
Nos. 2,911,357, 3,173,857, 3,271,327, 3,280,041, 3,549,720,
3,759,823 and 3,703,461, GB 1,501,346 and WO 98/35,754.
[0011] While some of these catalysts are useful for hydrogenating
various unsaturated feed streams, there is still a need for
improved hydrogenation catalysts.
[0012] In addition, prior art noble metal catalysts are still
susceptible to poisoning from sulfur and/or nitrogen present in
conventional feed streams. Thus, improved catalysts which have a
tolerance for sulfur are also needed.
[0013] It is therefore an object of the invention to provide a
novel hydrogenation catalyst.
[0014] It is another object of the invention to provide an improved
hydrogenation catalyst for the conversion of aromatics in a feed
stream, where the catalyst has high activity.
[0015] It is another object of the invention to provide an improved
hydrogenation catalyst for the conversion of benzene to
cyclohexane, where the catalyst has high activity and
selectivity.
[0016] It is another object of the invention to provide an improved
hydrogenation catalyst with a tolerance for low to medium levels of
sulfur in a feed stream.
[0017] It is another object of the invention to provide an improved
hydrogenation catalyst containing platinum and palladium on a
transition alumina carrier.
[0018] It is another object of the invention to provide an improved
hydrogenation catalyst for the removal of aromatics from a feed
stream, where the catalyst comprises one or more noble metals,
preferably platinum and palladium, placed on a predominantly theta
alumina carrier.
[0019] These and other objects of the invention are obtained by the
product and process of the present invention.
SUMMARY OF THE INVENTION
[0020] The invention is directed to an improved hydrogenation
catalyst for the hydrogenation of aromatics and other unsaturated
compounds in a hydrocarbon feed stream, which boils in the range
from about 200 to about 1100.degree. F., and which may contain up
to about 150 ppm of total sulfur. The catalyst of this invention
includes from about 100 ppm to about 5 percent by weight of each of
platinum and palladium, preferably from about 0.1 to about 1.0
percent platinum and from about 0.2 to about 2.0 percent palladium.
The preferred molar ratio of platinum to palladium in the catalyst
is from about 1 to 4 to about 1 to 7. The carrier for the catalyst
is an inert alumina carrier, wherein the alumina preferably
comprises at least about 50 percent theta (or delta) alumina, with
the remaining portion of the carrier being preferably alpha
alumina, preferably from about 1 to about 40 percent. Minor amounts
of other transition aluminas may also be present.
[0021] The invention is also directed to a process for the
hydrogenation of feed streams containing aromatic or other
unsaturated hydrocarbons and less than about 150 ppm of sulfur in
contaminants by use of the above-described catalyst.
[0022] The invention is also directed to a process for the
production of the above-referenced hydrogenation catalyst.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The catalyst of the invention is preferably a bimetallic,
Group VIII catalyst, wherein the Group VIII elements are preferably
platinum and palladium, which are impregnated on an inert catalyst
support or carrier. While other noble metals may be used for the
catalyst, it has been discovered that superior hydrogenation
catalysts are produced when platinum and palladium are
utilized.
[0024] The catalyst support or carrier for the platinum and
palladium is preferably a medium to low surface area alumina
carrier, more preferably a predominantly theta (or delta) alumina
carrier. Preferably the surface area of the carrier is from about
30 to about 150 m.sup.2/g, more preferably 30-110 m.sup.2/g, most
preferably from about 60 to about 100 m.sup.2/g. Theta (or delta)
alumina comprises at least about 50 percent of the carrier,
preferably at least about 60 percent. In order to maintain a
relatively low surface area of less than about 150 m.sup.2/g for
the catalyst, up to about 40 percent of the carrier may also
constitute an alpha alumina. Any combination of theta (or delta)
alumina carrier and alpha alumina carrier which produces a carrier
with a surface area within the preferred range is within the scope
of the invention. Minor amounts of other transition aluminas may
also be present in the carrier.
[0025] Various transition states of alumina are formed during
thermal treatment of hydrated alumina. Their specific transition
state is defined based on a number of considerations, including
crystal structure, method of formation and surface area. At least
seven transition forms of alumina are recognized, as discussed in
Kirk-Othmer, Encyclopedia of Chemical Technology, Second Edition,
Volume 2, pages 48-58 (1963). Three of these forms, chi, eta, and
gamma, are poorly crystallized and three, kappa, delta and theta,
are relatively well crystallized. A seventh form, rho alumina, may
be considered amorphous. (Some authorities have asserted that rho
alumina is also crystallized, but more poorly crystallized than
gamma alumina.)
[0026] The specific surface area of the chi and eta forms of
transition alumina are relatively high, ranging from 250 to 500
m.sup.2/g with the specific surface area of gamma alumina ranging
from 150-300 m.sup.2/g. In contrast, the surface areas of kappa,
theta and delta alumina are significantly lower with the surface
area of delta and theta alumina generally in the range of about 60
to 100 m.sup.2/g. The specific surface area of alpha alumina is
lower still, generally less than about 30 m.sup.2/g. Because of its
relatively high surface area and ease of formation, gamma alumina
has been frequently utilized as a carrier of choice for certain
noble metal hydrogenation catalysts, such as those disclosed in
U.S. Pat. Nos. 3,280,041, 4,049,576, 3,943,053 and 4,713,363.
[0027] Besides surface area, additional differences exist among the
various forms of transition alumina as disclosed more completely on
Table 3 of the article from Kirk Othmer which is referenced above.
For example, the temperature needed to form the delta (and theta)
forms of transition alumina is significantly higher
(900-1000.degree. C.) than that which is used to form the rho, eta
and gamma forms of transition alumina (200-600.degree. C.).
[0028] Because the specific surface area and crystal structure of
theta and delta alumina are so similar, it is often difficult to
distinguish between these two forms of alumina. Therefore, for
purposes of this invention, all references to theta alumina also
include delta alumina.
[0029] It has been surprisingly discovered that improved palladium
and platinum catalysts for the hydrogenation of aromatic feed
streams containing sulfur contaminants can be prepared from theta
alumina carriers. This is surprising as the surface area of a
carrier using theta alumina is significantly less than that of a
conventional gamma alumina carrier used for the hydrogenation
process as disclosed, for example, in U.S. Pat. No. 4,049,576.
[0030] Any reasonable method for depositing the platinum and the
palladium on the referenced carrier can be used. In one preferred
embodiment to impregnate the carrier with platinum and palladium,
an aqueous solution, preferably consisting of chloroplatinic acid
and palladium chloride, such as is supplied by Colonial Metals, is
first prepared. The amount of chloroplatinic acid and palladium
chloride dissolved in an aqueous solution is the amount sufficient
to provide a final calcined catalyst containing from 100 ppm to
about 5.0 percent by weight each of elemental platinum and
palladium metals. Preferably, the platinum present in the catalyst
comprises from about 0.1 to about 1.0 percent by weight and the
palladium present in the catalyst comprises from about 0.2 to about
2.0 percent by weight. In a more preferred embodiment, the platinum
comprises from about 0.1 to about 0.5 percent by weight and the
palladium from about 0.2 to about 1.0 percent by weight of the
catalyst. The preferred molar ratio of the platinum to the
palladium in the catalyst is from about 1 to 3 to about 1 to 9,
preferably from about 1 to 4 to about 1 to 7.
[0031] Because of the use of platinum and/or palladium chlorides in
preparing the catalyst, the finished catalyst may also contain
residual quantities of chlorides, from about 0.1 up to about 2
percent by weight. Surprisingly, the presence of chlorides in this
range in the final catalyst may actually improve the overall
performance of the catalyst.
[0032] To prepare the catalyst, the alumina carrier, which
comprises predominantly theta alumina, is first prepared. To form
the carrier a precursor material, such as boehmite powder, is first
mixed with water and, if necessary, a suitable peptizing agent,
such as an acid, to improve its mechanical strength. The carrier is
then dried at low temperature to evaporate water and is then
calcined at a temperature from about 1500 to about 2500.degree. F.
(816 to about 1371.degree. C.) to form theta alumina. The
composition of the alumina is confirmed by conventional
characterization procedures, such as x-ray diffraction. The alumina
carrier may include, in addition to theta alumina, various amounts
of alpha alumina. Preferably, the theta alumina comprises at least
about 50 percent of the carrier, more preferably, at least about 60
percent, with the remaining portion being alpha alumina, preferably
from about 1 to about 40 percent, by weight. Minor amounts of other
aluminas may also be present, such as gamma alumina, but in amounts
less than about 5 percent. Heat treatment of the carrier reduces
the surface area of the catalyst preferably to a range from about
30 to about 150 m.sup.2/g, more preferably from about 50 to about
110 m.sup.2/g, most preferably about 60 to about 100 m.sup.2/g with
a pore volume in the range of about 0.3 to about 0.7 cc/g. Any
combination of theta alumina carrier and alpha alumina carrier
which produces a carrier within the required surface area is within
the scope of the invention.
[0033] The carrier can be formed in any conventional shape such as
a powder, pellet, extrudate or sphere. Preferably, the carrier is
formed into an extrudate of small size, preferably less than about
0.25 inch (0.6 cm.) in diameter.
[0034] Once the predominantly theta alumina carrier is formed, the
platinum and palladium components are added. Any conventional
process for impregnating a carrier with platinum and palladium is
within the scope of the invention. In one embodiment, the carrier
is impregnated with a solution of the chloroplatinic acid and
palladium chloride. The amount of chloroplatinic acid and palladium
chloride present in the solution depends on the level of palladium
and platinum loadings desired on the predominantly theta alumina
carrier. The wet catalyst is covered and left to absorb the
materials for an extended period of time, preferably from about 2
to about 24 hours. The catalyst is then allowed to dry at ambient
temperature for about 24 hours.
[0035] The catalyst may also be prepared by an incipient wetness
process.
[0036] The dried catalyst is then calcined at a temperature up to
about 500.degree. C. (932.degree. F.) for about 2 hours. At the
conclusion of the calcining operation, the catalyst is ready for
reduction. Reduction is accomplished by heating the catalyst
composition in the presence of hydrogen at a temperature between
about 500.degree. F. (260.degree. C.) and about 842.degree. F.
(450.degree. C.) at a pressure of about 0 to about 2,000 psig for 3
hours. Alternatively, the catalyst may be reduced in situ by
passing hydrogen gas at the above-referenced temperatures and under
the above-referenced pressure.
[0037] It has been discovered that the catalyst prepared by the
above-described process is "sulfur tolerant." "Sulfur tolerant"
means that the catalyst will not substantially deactivate during
the hydrogenation reaction with a certain level of sulfur present
in the feed stream. This sulfur tolerance means that the
hydrogenation catalyst of the invention is utilizable in
conventional hydrogenation procedures wherein the feed streams
contain modest levels of sulfur (less than about 150 ppm of total
sulfur in the form of sulfur compounds) and remains active for a
conventional length of time, i.e., the catalyst has a reasonable
life cycle. The length of time that the catalyst of the invention
retains good activity varies, depending on the specific feed stream
utilized and other variables well recognized in the art.
Notwithstanding, the catalyst of the invention is at least as, or
more, sulfur tolerant as conventional sulfur tolerant hydrogenation
catalysts used for the referenced hydrogenation process as where
cracking and shift in boiling point are undesirable.
[0038] The catalyst of this invention preferably acts as a
hydrogenation catalyst for the hydrogenation of unsaturated
components in a liquid hydrocarbon stream. These feedstocks
usually, or at least often, contain relatively high percentages of
olefins and mononuclear and polynuclear aromatics which require
further hydrogenation. The catalyst of this invention can also
serve as a hydrogenation catalyst for aromatics, olefins and
diolefins and for the hydrogenation of benzene to cyclohexane. The
presence of sulfur compounds in many of these feedstocks often
complicates the hydrogenation process by poisoning the metal
catalyst used for hydrogenation. The catalyst of the present
invention is tolerant of reasonable levels of sulfur or sulfur
compounds in the feed stream, as discussed above.
[0039] It has been surprisingly discovered that a catalyst formed
by the above-referenced process using predominantly theta (or
delta) alumina catalyst perform better than conventional platinum
and palladium catalyst deposited on a gamma alumina carrier as
disclosed, for example, in U.S. Pat. No. 4,049,576.
EXAMPLES
[0040] The following examples describe the invention in more
detail. Parts and percentages are by weight unless otherwise
designated.
Example 1
[0041] A conventional alumina carrier in extrusion was formed by
mixing boehmite powder with water and, if needed, by adding a
peptizing agent to improve its mechanical strength. The carrier was
extruded into a conventional shape with a diameter of about
{fraction (1/20)} in. The formed carrier was dried at a low
temperature to evaporate water and then calcined with the
temperature ramped to a final temperature of 1500 to 2500.degree.
F. (816 to about 1371.degree. C.) and kept at the final temperature
for 2-30 hours to produce a carrier comprised 96 percent theta
alumina and 4 percent alpha alumina. Confirmation of the structure
of the carrier was provided by x-ray diffraction. The carrier was
then impregnated using an incipient wetness technique using a
solution of hexachloroplatinic acid and palladium chloride of
sufficient concentration to result in the platinum and palladium
loadings referenced below. The catalyst carrier was left covered in
the solution and allowed to soak for 18 to 24 hours. The catalyst
was then uncovered and allowed to dry at ambient temperatures for
about 24 hours. The dried catalyst was calcined in a furnace with
the temperature raised in 10.degree. C. increments and held for two
hours at each of the following temperatures: 140.degree. C.,
300.degree. C. and 500.degree. C.
[0042] The catalyst contained 0.20 percent by weight platinum, 0.57
percent by weight palladium and 0.45 percent by weight chloride.
The carrier for the catalyst had a surface area of 84 m.sup.2/g and
a pore volume of 0.44 cc/g as shown in Table 1.
[0043] The performance of the catalyst was tested for hydrogenation
of aromatics in a HCLGP/LGO light gas oil blend containing 25
weight percent total aromatics, 50 ppms S, 2 ppm WN with the
results shown in Table 1.
Example 2
[0044] The same procedure of Example 1 was followed except the
steps of soaking and room temperature drying were omitted. The
catalyst contained 0.19 percent platinum, 0.56 percent palladium,
and 0.39 percent chloride by weight.
Comparative Example 3
[0045] The carrier used was a gamma alumina formed and calcined by
conventional procedures. That the carrier was predominantly gamma
alumina was confirmed by x-ray diffraction. The surface area of the
carrier was 205 m.sup.2/g with a pore volume of 0.61 cc/g. The
other procedures performed for preparing the catalyst were the same
as in Example 1. The catalyst contained 0.21 percent platinum and
0.59 percent palladium.
Example 4
[0046] A larger pore carrier was prepared with the addition of a
burn-out material which was calcined using the procedures of
Example 1. It contained approximately 63 percent theta alumina and
37 percent alpha alumina. The impregnation and calcination
procedures were the same as in Example 2. The catalyst contained
0.19 percent by weight platinum, 0.585 percent by weight palladium
and 0.38 percent by weight chloride.
Comparative Example 5
[0047] A catalyst was produced according to the procedure disclosed
in U.S. Pat. No. 4,049,576, Example 1. The carrier extrusion was a
gamma alumina prepared as in Comparative Example 3. The
concentration of the platinum and palladium on the carrier was 0.19
percent and 0.59 percent by weight respectively.
Catalyst Activation and Performance Tests
[0048] 12.3 g by mass of each catalyst of each Example was loaded
into a reactor, dried at 300.degree. C. for two hours under a
nitrogen flow. The reactor was pressurized with hydrogen to 550
psig pressure. The catalyst was thus reduced at 300.degree. C. with
hydrogen for 3 hours and cooled to 260.degree. C. The reduced
catalyst was tested for hydrogenation of aromatics in a light gas
oil feed containing 25 weight percent total aromatic compounds,
about 3.8 percent poly aromatics, 50 ppm WS and 2 ppm WN. The tests
were run at 550 psig and 550.degree. F., H.sub.2/HC of 2000 scf/bbl
and an LHSV of 1.2 l/l/hr.
[0049] The test results of these samples are summarized in Table 1.
The catalyst with the highest aromatics conversion, i.e., the least
amount of aromatics remaining in the product was the most active.
As is proved by these examples, the catalyst of Examples 1, 2 and 4
using the predominantly theta alumina carrier were significantly
more active than the gamma alumina carrier catalysts of Comparative
Example 3 or Comparative Example 5 produced by the process
disclosed in U.S. Pat. No. 4,049,576.
[0050] The principal preferred embodiments and modes of operation
of the present invention have been described in the foregoing
specification. The invention which is intended to be protected
herein, however, is not to be construed as limited to the
particular forms disclosed as these are to be regarded as
illustrative rather than restrictive. In particular, the
application of the catalyst of this invention is specifically not
limited to the hydrogenation of aromatics in hydrocarbons.
Variations and changes may be made by those skilled in the art
without departing from the spirit of the invention.
1 TABLE 1 % Total Carrier Aromatics Pore Palladium Platinum
Remaining in Surface Volume, % Pd on % Pt on Product After Example
Type Area, m.sup.2/g cc/g Source Catalyst Source Catalyst Treatment
1 96% theta, 84 0.44 palladium 0.57 hexachloroplatinic 0.20 0.3 4%
alpha chloride acid alumina 2 96% theta 84 0.44 palladium 0.56
hexachloroplatinic 0.19 0.2 4% alpha chloride acid alumina Compar-
gamma 205 0.61 palladium 0.59 hexachloroplatinic 0.21 1.4 ative
alumina chloride acid 3 4 63% theta, 85 0.56 palladium 0.585
hexachloroplatinic 0.19 <0.1 37% alpha chloride acid alumina
Compar- gamma 205 0.61 palladium 0.59 hexachloroplatinic 0.19 3.4
ative alumina chloride acid 5
* * * * *