Hydrocracking catalysts comprise a Group VIB and/or non-noble metal Group VIII hydrogenation component in conjunction with an LZ-210 zeolite preferably of SiO.sub.2 :Al.sub.2 O.sub.3 greater than 9.0, which zeolite has been hydrothermally treated and ammonium ion-exchanged. In a preferred embodiment, the zeolite is essentially free of rare earth metals, and most preferably, essentially free of all metals except the Group VIB or non-noble Group VIII.

INTRODUCTION 
The present invention relates to a hydrocracking catalyst and process, and 
particularly to a zeolite-containing hydrocracking catalyst and its use in 
hydrocracking gas oil feeds and the like into gasoline. 
Hydrocracking is a well-known refining process wherein, in its typical 
form, a relatively high boiling hydrocarbon feedstock is upgraded by 
contact with a hydrocracking catalyst under conditions of elevated 
temperature and pressure and the presence of added hydrogen. In 
hydrocracking, the catalyst promotes two reactions, first the cracking of 
a substantial proportion of the hydrocarbon components of the feedstock 
and, second, the saturation of the resultant products by hydrogenation. 
The net result of hydrocracking is that the relatively high boiling feed 
is converted into a lower boiling feed with a greater proportion of 
components boiling in a desired range, e.g., C.sub.4 + to 420.degree. F. 
in the case of hydrocracking to produce gasoline, 300.degree. to 
700.degree. F. in the case of midbarrel hydrocracking to produce diesel 
fuel, and 300.degree. to 550.degree. F. in the case of midbarrel 
hydrocracking to produce certain aviation fuels. 
For the production of gasoline from gas oils and the like, the typical 
hydrocracking catalyst is composed of one or more Group VIB or VIII metals 
on a support comprising a zeolite having catalytic cracking activity. One 
such zeolite is known as LZ-210, disclosed most fully in U.S. Pat. No. 
4,503,023 issued to Breck et al. and assigned to Union Carbide, which 
patent is herein incorporated by reference in its entirety. LZ-210 is a 
distinctive form of zeolite in that, while its crystal structure is 
similar to a Y zeolite, it has an unusually high framework 
silica-to-alumina ratio, above 6.0, due to the extraction of aluminum from 
the Y zeolite structure by contact with an aqueous solution of a 
fluorosilicate salt and incorporation of silicon from the solution into 
the zeolite structure. 
In a subsequent disclosure, in European Patent Application No. 84104815.0, 
Publication No. 0124120, published Nov. 7, 1984 by Best et al., also 
assigned to Union Carbide, which patent application is herein incorporated 
by reference in its entirety, two forms of LZ-210, denominated LZ-210-T 
and LZ-210-M, are disclosed, with the former being a thermally or 
hydrothermally treated form of LZ-210 and the latter a LZ-210 zeolite 
exchanged with a multivalent metal, preferably a rare earth metal or 
mixtures of rare earth metals. Both LZ-210-T and LZ-210-M have a 
silica-to-alumina ratio between 6.0 and 9.0, and this because Best et al. 
teach that a dramatic loss in hydrocracking performance results when the 
silica-to-alumina ratio exceeds 9.0. Specifically, what Best et al. teach 
is: "Surprisingly, it has been found that when the SiO.sub.2 to Al.sub.2 
O.sub.3 ratio of LZ-210-T is equal to or greater than 9.0 that the use of 
LZ-210-T falls off in its hydrocracking performance. Although the reasons 
for this markedly different performance are not known at present it is 
clear that the silica to alumina range of between greater than 6.0 and 
equal to or less than 9.0 is critical in the development of hydrocracking 
catalysts based upon LZ-210-T and LZ-210-M." 
The Best et al. patent application also teaches the benefits of exchanging 
an LZ-210 zeolite with multivalent metals, particularly rare earth metals. 
The benefits disclosed are improved catalyst activity and long life as 
compared to other forms of LZ-210 and as compared to Y zeolites. Another 
disclosed benefit is an improvement in rejuvenability. 
It should be noted that neither the Breck et al. patent nor the Best et al. 
patent application, above cited, are to be construed as admitted prior art 
as to the present invention. 
SUMMARY OF THE INVENTION 
In the present invention it has been surprisingly found that hydrocracking 
catalysts comprising a hydrothermally treated and ammonium-exchanged 
LZ-210 zeolite having a silica-to-alumina ratio above 9.0 have higher 
catalytic activity than similar catalysts containing LZ-210 zeolite of 
lower silica-to-alumina ratio. Accordingly, the present invention is 
directed to a hydrocracking catalyst containing one or more hydrogenation 
components selected from the Group VI and VIII metals on a support 
comprising a hydrothermally treated and ammonium-exchanged LZ-210 zeolite 
of silica-to-alumina ratio above 9.0, preferably between about 10 and 20, 
and most preferably from 11 to 15. 
In the preferred embodiment, the catalyst is essentially free of Group VIII 
noble metals and contains non-noble Group VIII metals instead. The 
non-noble Group VIII metal may be distributed upon the catalyst support in 
any convenient manner, but in a preferred embodiment, the catalyst 
contains a novel zeolite containing the non-noble metal cation exchanged 
into the LZ-210 zeolite. 
In another embodiment of the invention, it has been discovered that LZ-210 
zeolites, exchanged with one or more rare earth metals, have lower 
activity for hydrocracking when the hydrocracking catalyst is promoted 
with a non-noble Group VIII metal. Therefore, for non-noble metal 
hydrocracking catalysts, it is critical in the invention that the LZ-210 
zeolite be essentially free of rare earth metals, and even more 
preferably, essentially free of all metals except hydrogenation metals 
selected from the group consisting of Group VIB metals and non-noble Group 
VIII metals. 
In yet another embodiment of the invention, it has been found that, even 
for LZ-210 zeolites having a silica-to-alumina ratio as low as 6.0, one 
may obtain useful hydrocracking results with non-noble Group VIII metals 
present as a hydrogenation promoter. However, because the best results 
have been found to be obtained at a silica-to-alumina ratio above 9.0, all 
the preferred embodiments of the present invention employ an LZ-210 
zeolite of silica-to-alumina ratio above 9.0. 
The following definitions pertain to the present application. The term 
"noble metal" refers to platinum, palladium, rhodium, iridium, ruthenium, 
and osmium. The term "rare earth metal" refers to lanthanum, cerium, 
praseodymium, neodymium, samarium, europium, gadolinium, terbium, 
dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. 
DETAILED DESCRIPTION OF THE INVENTION 
In the present invention, hydrocracking catalysts are provided containing 
as a cracking component a form of LZ-210 zeolite, and specifically an 
LZ-210 zeolite having a silica-to-alumina ratio above 6.0, preferably 
above 9.0, and more preferably from 10 to 20. Generally, LZ-210 zeolites 
prove unstable to thermal treatment at a SiO.sub.2 :Al.sub.2 O.sub.3 ratio 
somewhere between about 15 and 20. It is for this reason that the most 
preferred LZ-210 zeolites herein have a silica-to-alumina ratio from 10 to 
15, with the most highly preferred LZ-210 zeolite having a 
silica-to-alumina ratio from 11 to 15. 
The most preferred LZ-210 zeolites of the present invention have, in the 
dehydrated state, a chemical composition expressed in terms of mole ratios 
of oxides as 
EQU (0.85-1.1)M.sub.2/n O.Al.sub.2 O.sub.3 :xSiO.sub.2 
wherein "M" is a cation having the valence "n" and "x" is a value between 
about 10 and about 15, and most preferably between about 11 and about 15, 
having extraneous silicon atoms in its crystal lattice in the form of 
SiO.sub.4 tetrahedra, preferably in an average amount of at least 1.0 per 
10,000A.sup.3, and having an X-ray powder diffraction pattern having at 
least the d-spacings set forth in the table below: 
TABLE I 
______________________________________ 
d(A) Intensity 
______________________________________ 
14.30-13.97 very strong 
8.71-8.55 medium 
7.43-7.30 medium 
5.66-5.55 strong 
4.75-4.66 medium 
4.36-4.28 medium 
3.76-3.69 strong 
3.30-3.23 strong 
2.88-2.79 strong 
______________________________________ 
The Breck patent previously mentioned provides a detailed method for 
preparing LZ-210 zeolites, as well as a detailed explanation of the 
properties of LZ-210 zeolites (i.e., their defect structure and the like). 
The preferred embodiment of the present invention requires the use of 
those LZ-210 zeolites which, through appropriate treatment of a Y zeolite 
or the like with a fluorosilicate, have a silica-to-alumina ratio above 9, 
more preferably between 10 and 20, and most preferably between 10 and 15. 
In the usual case, the preferred LZ-210 zeolite is prepared by contacting 
and reacting a Y zeolite of SiO.sub.2 :Al.sub.2 O.sub.3 between 3 and 6, 
and preferably an ammonium-exchanged Y zeolite of SiO.sub.2 :Al.sub.2 
O.sub.3 between 3 and 6, at a temperature usually from 20.degree. to 
95.degree. C. with a fluorosilicate, preferably ammonium fluorosilicate, 
in an amount and under conditions such that sufficient of the framework 
aluminum atoms are removed and replaced with silicon atoms resulting in a 
final SiO.sub.2 :Al.sub.2 O.sub.3 above 9.0. Usually, the amount of 
fluorosilicate and the conditions of contacting/reacting are such that at 
least 60 percent, preferably at least 75 percent, more preferably at least 
80 percent, and most preferably at least 90 percent, of the crystal 
structure of the original Y zeolite is retained. After reaction is 
complete, the LZ-210 zeolite is removed from the contacting/reacting 
medium, generally washed with deionized or distilled water, and then 
dried, usually at a temperature between 20.degree. and 50.degree. C. 
The LZ-210 zeolite is then stabilized by a hydrothermal treatment. 
Typically, the zeolite is contacted at an elevated temperature, usually in 
the range of 500.degree. C. to the temperature at which the zeolite loses 
substantial crystallinity, preferably in the range of 500.degree. to 
850.degree. C., with a flowing gas stream which contains sufficient water 
vapor to impart a partial pressure of at least 0.2 p.s.i., preferably at 
least 2 p.s.i., and most preferably at least 10 p.s.i. The hydrothermal 
treatment (or steam calcination) is conducted for a time period sufficient 
to effect some reduction in the unit cell size of the zeolite. Typically, 
the time for hydrothermal treatment is between 10 minutes and 4 hours, 
preferably between 0.5 and 1.5 hours, when using pure steam at a total 
pressure of 15 p.s.i.g. 
Following the steam calcination, the LZ-210 zeolite is subjected to an 
ammonium ion exchange to reduce the sodium content, typically to a value 
below 0.5 weight percent, and preferably to below 0.2 weight percent, 
calculated as Na.sub.2 O. Methods for ion exchanging zeolites with 
ammonium ion are well known and therefore need not be described in great 
detail. Usually, the exchange is accomplished with a warmed solution of an 
ammonium salt, e.g., ammonium chloride, ammonium nitrate, ammonium 
acetate, ammonium sulfate, and the like, and the exchange treatment may be 
repeated with fresh solution one or more times, usually with a water wash 
between exchange treatments. 
Ordinarily, to achieve extremely low sodium levels in the final zeolite, it 
will prove necessary to repeat the ion exchange procedure at least once if 
sodium levels below about 0.05 weight percent (calculated as Na.sub.2 O) 
are desired. More often, the ion exchange procedure will be repeated at 
least twice, and occasionally several times, before reductions in sodium 
content below 0.05 weight percent are achieved. 
After the ammonium ion exchange, the LZ-210 zeolite is separated from the 
ion exchange solution, washed free of any residual ion exchange solution, 
and then heated at 100.degree. to 200.degree. C. for a time period 
sufficient to produce a dried product. Usually, time periods of one to two 
hours prove effective. 
The dried zeolite product containing the ammonium cations is useful as an 
adsorbent, for example, in dehydrating gases containing water vapor. The 
zeolite product is also useful as a molecular sieve and as a catalyst for 
promoting hydrocarbon conversion reactions, especially with respect to 
acid catalyzed hydrocarbon conversion reactions, such as cracking, 
alkylation, isomerization, etc., or for acid catalyzed reactions coupled 
with hydrogenative reactions, such as hydrocracking, hydroisomerization, 
and the like. For cracking, alkylation, and other non-hydrogenative 
reactions, the zeolite is ordinarily dispersed in a porous refractory 
oxide matrix usually composed of alumina, silica, magnesia, beryllia, 
zirconia, titania, thoria, chromia, or combinations thereof, such as 
silica-alumina, silica-zirconia, and the like. For hydrocracking and other 
combined hydrogenative-acid catalyzed reactions, one or more hydrogenation 
components are further added, with Group VIB and VIII metals, often in 
combination, being utilized for this purpose. 
When used for catalytic hydrocarbon conversion purposes, the hydrothermally 
treated and ammonium-exchanged LZ-210 zeolite is, at some point in the 
catalyst preparation procedure, calcined at an elevated temperature, 
usually in the 600.degree. to 1600.degree. F. range, preferably in the 
900.degree. to 1500.degree. F. range. This calcination procedure may be 
applied to the dried zeolite product prior to admixture with other 
catalytic materials or, as is more often the case, to the zeolite when 
further combined in particulate form with a precursor of the desired 
refractory oxide (for instance, alumina gel in the case of alumina, silica 
gel in the case of silica, etc.), or with a salt containing one or more 
desired hydrogenation metals, or with both. Calcination after admixture 
with other catalytic materials serves several purposes at once. In 
addition to converting the zeolite of the invention to a form more active 
for acid catalyzed hydrocarbon conversion reactions by the decomposition 
of the ammonium ions to hydrogen ions and hydroxyl groups, calcination 
will further convert the refractory oxide precursor to its desired form, 
e.g., gamma alumina, and the hydrogenation metal salt to the corresponding 
metal oxide. Further still, the calcination hardens catalytic materials 
containing refractory oxide precursors into particulates suitable for use 
in a commercial service, i.e., as a fixed or fluidized bed. 
The zeolites of the present invention, although useful in a wide variety of 
hydrocarbon conversion catalysts, find especial usefulness in 
hydrocracking catalysts. As stated hereinbefore, the typical hydrocracking 
catalyst of the invention contains one or more hydrogenation metal 
components, a porous refractory oxide, and the zeolite of the invention. 
Ordinarily, the hydrogenation metal chosen is a Group VIB or VIII metal, 
with at least some of said Group VIII metal usually being incorporated in 
the zeolite by cation exchange after the ammonium ion exchange or after a 
calcination subsequent to the ammonium ion exchange. If desired, a Group 
VIB metal, and particularly molybdenum, may also be ion-exchanged into the 
zeolite, as for example by the method disclosed in U.S. Pat. No. 
4,297,243, herein incorporated by reference. More commonly, however, if a 
Group VIB metal is utilized, it is usually introduced after the zeolite is 
admixed with a refractory oxide component, the usual procedure being to 
calcine the admixture, impregnate with a solution containing the Group VIB 
metal in an anionic form, such as ammonium heptamolybdate, and calcining 
again. Normally, the Group VIII metal, if a noble metal, will be 
introduced by cation exchange prior to admixture with the refractory oxide 
component, but if a non-noble metal is chosen as the Group VIII metal, it 
is typically introduced in cationic form into the zeolite by impregnation 
at a time subsequent to admixing the zeolite and refractory oxide but 
prior to the final calcination. In this latter embodiment, it is usually 
the case that the non-noble metal is introduced into the catalyst at the 
same time as the Group VIB metal, usually by impregnation with an aqueous 
solution containing Group VIII metal cations and the Group VIB metal in an 
anionic form. 
One of the surprising discoveries of the present invention is that the 
presence of rare earth elements in the zeolite, although taught as 
desirable in the previously mentioned Best et al. European patent 
application, actually proves detrimental when the catalyst is promoted 
with non-noble metal hydrogenation components. Therefore, in the preferred 
embodiment of the invention as it relates to non-noble metal hydrogenation 
catalysts, it is critical in the present invention that the zeolite be 
essentially free of rare earth elements, and preferably essentially free 
of all stabilizing polyvalent metals, and most preferably essentially free 
of all metals except non-noble metal hydrogenation metals. 
Catalysts prepared in accordance with this embodiment of the invention 
contain a non-noble metal selected from the Group VIII metals, preferably 
nickel or cobalt, or from the Group VIB metals, such as molybdenum, 
tungsten, or chromium, with molybdenum and tungsten preferred. Most 
preferably in this embodiment, the catalyst contains both a Group VIB 
metal and a non-noble metal Group VIII metal in combination, with the most 
preferred combination being nickel and tungsten. Such catalysts, as stated 
previously, are usually prepared by impregnating particulates containing 
the zeolite mixed with a refractory oxide, although it is also possible to 
admix salts of the desired hydrogenation metal with the zeolite and a 
refractory oxide component, such as peptized alumina, alumina gel, or 
hydrated alumina, usually with a binder such as alumina Catapal.RTM., and 
then providing the catalyst in particulate form by extrusion through a die 
having openings of desired size and shape followed by breaking or cutting 
the extruded matter into lengths of about 1/16 to 1/2 inch. The preferred 
procedure differs in that only the zeolite and refractory oxide components 
are extruded, with the subsequent particulate matter then being 
impregnated with one or more solutions, and most preferably only one 
solution, containing the desired hydrogenation metals. In either case, 
however, the resulting material containing the hydrogenation metal, 
zeolite, and refractory oxide in particulate form is calcined at an 
elevated temperature, usually between about 600.degree. and 1600.degree. 
F., to produce catalytic particles of high crushing strength. 
One preferred shape for the calcined particulates is cylindrical, with 
cross-sectional diameters between about 1/32 and 1/8 inch. Another 
preferred shape is that of a three-leaf clover, as shown in FIGS. 8 and 8A 
of U.S. Pat. No. 4,028,227, herein incorporated by reference in its 
entirety, with the preferred cross-sectional shape having a maximum length 
D as shown in said FIG. 8A of about 1/22 inch and a lobe diameter d of 
about 0.28 inch. Extrusions with shapes of four lobes are also among the 
preferred shapes. 
The calcination procedure converts the hydrogenation components into the 
oxide form, and since hydrocracking catalysts are most active in the 
sulfide form, the catalyst is generally sulfided. One such method is in 
situ, i.e., by contact in a hydrocracking reactor with a sulfur-containing 
feedstock under hydrocracking conditions. However, if it is desired to 
presulfide the catalyst prior to use in a hydrocracking reactor, the 
presulfiding can typically be accomplished by contact at an elevated 
temperature with a reducing gas containing hydrogen sulfide, e.g., a mix 
of 90 percent H.sub.2 and 10 percent H.sub.2 S, by volume. 
Typically, the finished catalyst contains at least about 0.3 weight percent 
of hydrogenation components, calculated as the metals. In the usual 
instance, wherein a Group VIII metal and a Group VIB metal component are 
present in combination, the finished catalyst contains between about 5 and 
35 percent, preferably between about 10 and 30 percent by weight, 
calculated as the respective trioxides, of the Group VIB metal components 
and between about 2 and 15 percent, preferably between 3 and 10 percent by 
weight, calculated as the respective monoxides, of the Group VIII metal 
components. 
If desired, a phosphorus component may also be incorporated in the catalyst 
by either comulling the support materials with phosphoric acid or 
including phosphoric acid in the impregnating solution. Usual and 
preferred proportions of phosphorus in the catalyst fall in the ranges of 
1 to 10 weight percent and 3 to 8 weight percent, calculates as P.sub.2 
O.sub.5. 
Hydrocracking catalysts prepared with LZ-210 zeolite are useful in the 
conversion of a wide variety of hydrocarbon feedstocks to a hydrocarbon 
product of lower average boiling point and molecular weight. The 
feedstocks that may be subjected to hydrocracking by the method of the 
invention include all mineral oils and synthetic oils (e.g., shale oil, 
tar sand products, etc.) and fractions thereof. Illustrative feedstocks 
include straight run gas oils, vacuum gas oils, and catcracker 
distillates. The typical hydrocracking feedstock, however, contains a 
substantial proportion of components, usually at least 50 percent by 
volume, often at least 75 percent by volume, boiling above the desired end 
point of the product, which end point, in the case of gasoline, will 
generally be in the range of about 380.degree. to 420.degree. F. Usually, 
the feedstock will also contain gas oil components boiling above 
550.degree. F., with highly useful results being achievable with feeds 
containing at least 30 percent by volume of components boiling between 
600.degree. and 1000.degree. F. 
For best results in hydrocracking, the catalyst of the invention will be 
employed as a bed of catalytic particulates in a hydrocracking reactor 
vessel into which hydrogen and the feedstock are introduced and passed in 
a downwardly direction. Operating conditions in the reactor vessel are 
chosen so as to convert the feedstock into the desired product, which, in 
the preferred embodiment, is a hydrocarbon product containing a 
substantial proportion of gasoline components boiling, for example, in the 
C.sub.4 to 420.degree. F. or the 185.degree. to 420.degree. F. range. The 
exact conditions required in a given situation will depend upon the nature 
of the feedstock, the particular catalyst composition utilized, and the 
desired product boiling range. But in general, the conditions of operation 
will fall into the following suitable and preferred ranges shown in the 
following Table II: 
TABLE II 
______________________________________ 
Conditions Suitable Preferred 
______________________________________ 
Temperature, .degree.F. 
450-850 500-800 
Pressure, p.s.i.g. 
750-3500 1000-3000 
LHSV 0.3-5.0 0.5-3.0 
H.sub.2 /Oil, MSCF/bbl as 
1-10 2-8 
measured at 60.degree. F. 
and 1 atmosphere 
______________________________________ 
The foregoing conditions in Table II are generally correlated so as to 
achieve a conversion, on a crack per pass basis, of at least 40 percent, 
preferably at least 50 percent, and most preferably at least 60 percent by 
volume. The yield of C.sub.4 to 420.degree. F. gasoline is usually at 
least 50 percent, preferably at least 70 percent by volume, on a 
once-through basis. 
The following Examples illustrate the hydrocracking performance of 
catalysts of the invention. The examples, however, are illustrative only 
and are not intended to be construed as limiting the scope of the claims. 
The scope of the invention is defined hereinafter in the claims.

EXAMPLE I 
These hydrocracking catalysts were prepared and tested for their activity 
for hydrocracking against a reference catalyst. The four catalysts were 
prepared by the following procedures: 
Catalyst No. 1 
LZ-210 zeolite having a silica-to-alumina ratio of 6.5 was hydrothermally 
treated by contact for 1 hour at 600.degree. C. and 1 atmosphere pressure 
with a flowing stream consisting essentially of pure steam. The zeolite 
was then ammonium-exchanged by introducing 200 grams of the zeolite into a 
solution consisting essentially of 50 grams of ammonium nitrate in 1,000 
cc. deionized water for 3 hours held at a temperature between about 
80.degree. and 100.degree. C. The zeolite was then washed with deionized 
water and the ammonium exchange was repeated. This procedure reduced the 
sodium content of the zeolite to less than about 0.2 percent, calculated 
as Na.sub.2 O. 
The zeolite was then mixed with Catapal.RTM. alumina binder such that 80 
percent of the mix by weight was zeolite and the remainder the alumina. 
The mixture was extruded through a die containing circular openings of 
1/16 inch diameter, broken into pieces of about 1/8 to 1/4 inch in length, 
and calcined for about 1 hour at 930.degree. F. The extrudates were then 
impregnated with an aqueous solution containing about 0.2 gm/ml of nickel 
nitrate (Ni.sub.2 (NO.sub.3).sub.2.6H.sub.2 O) and 0.33 grams/ml of 
ammonium metatungstate (90 percent WO.sub.3 by weight). After removing 
excess liquid, the catalyst was dried at about 230.degree. F. and, after 
gradual heating to 930.degree. F., was then calcined at 930.degree. F. in 
flowing air for about 1 hour. The final catalyst contained about 4.4 
weight percent of nickel components, calculated as NiO, and about 23.0 
weight percent tungsten components, calculated as WO.sub.3. 
Catalyst No. 2 
This catalyst was prepared by the same procedure as Catalyst No. 1 except 
that the LZ-210 zeolite had a silica-to-alumina ratio of 9.1. 
Catalyst No. 3 
This catalyst was prepared by the same procedure as Catalyst No. 1 except 
that the LZ-210 zeolite had a silica-to-alumina ratio of 11.7. 
The catalysts were then evaluated for hydrocracking activity in separate 
runs wherein a gas oil feed plus added hydrogen is passed through a 
laboratory-sized reactor vessel containing 150 cc. of catalyst under the 
following conditions: 1,450 p.s.i.a., 1.7 LHSV, and a hydrogen-to-oil 
ratio of 8,000 SCF/bbl. The gas oil feed was a denitrogenated, 
desulfurized, unconverted fraction obtained from a previous integral 
hydrofining-hydrocracking operation; it had an API gravity of 38.degree. 
and a boiling range of about 360.degree. to 870.degree. F., with about 12 
percent by volume of the feed boiling below 400.degree. F. To simulate 
hydrocracking in an H.sub.2 S-containing atmosphere, thiophene and 
tert-butylamine were blended with the feedstock so as to provide 
respective sulfur and nitrogen concentrations of about 0.5 and about 0.2 
weight percent. The operating temperature utilized in the reactor vessel 
was adjusted periodically to maintain a total liquid product gravity of 
47.degree. API, which, by previously established correlations, corresponds 
to about a 40 volume percent conversion of the feedstock to a C.sub.4 to 
420.degree. F. gasoline product 
Each of the three catalysts was compared against a reference catalyst, 
which reference catalyst was a commercial hydrocracking catalyst. The 
temperature, after 100 hours of operation, at which the reference catalyst 
was used to maintain the 40 percent conversion, varied somewhat in the 
range of about 695.degree. to 705.degree. F., depending upon the reactor 
unit in which it was run. However, for any given reactor unit, the 
temperature differential between the catalyst tested therein and the 
reference catalyst was as follows: 
TABLE III 
______________________________________ 
SiO.sub.2 : 
Temperature Differential 
Al.sub.2 O.sub.3 
Required to Maintain 40% 
Catalyst Of Zeolite 
Conversion 
______________________________________ 
No. 1 6.5 -8.degree. F. 
No. 2 9.1 -18.degree. F. 
No. 3 11.7 -23.degree. F. 
______________________________________ 
What the foregoing data indicate is that Catalyst No. 1 is 8.degree. F. 
more active than the reference catalyst, Catalyst No. 2 18.degree. F. more 
active, and Catalyst No. 3 23.degree. F. more active. The 23.degree. F. 
differential indicates, based on previous kinetically established 
correlations, that Catalyst No. 3 is roughly twice as active as the 
reference catalyst, i.e., if both the reference catalyst and Catalyst No. 
3 were tested with all conditions except space velocity held constant, 
Catalyst No. 3 could process twice as much feed for the same energy input 
(i.e., heat input by fuel consumption) as the reference catalyst. 
The data in Table III also show that the performance of otherwise identical 
Ni-W-Al.sub.2 O.sub.3 -LZ-210 zeolite hydrocracking catalysts is a 
function of the silica-to-alumina ratio of the LZ-210 zeolite. 
Specifically, the catalysts having an LZ-210 zeolite of silica-to-alumina 
ratio above 9.0 had much greater activity than Catalyst No. 1 having a 
silica-to-alumina ratio of only 6.5. 
EXAMPLE II 
This Example compares the effectiveness of Catalysts Nos. 1 and 2 
previously described against similar catalysts containing a rare 
earth-exchange zeolite. 
Catalyst No. 4 
The procedure for preparing Catalyst No. 1 was repeated, except that, 
before the described hydrothermal treatment, the LZ-210 zeolite was 
cation-exchanged with a lanthanum-rich rare earth chloride solution so as 
to introduce rare earth cations into the zeolite. 
Catalyst No. 5 
The procedure for preparing Catalyst No. 2 was repeated, except that, 
before the described hydrothermal treatment, the LZ-210 zeolite was 
cation-exchanged with a lanthanum-rich rare earth chloride solution 
similar to that described for Catalyst No. 4 under similar conditions. 
When compared against the reference catalyst, by the test described in 
Example I, Catalyst No. 4 was found to be 3.degree. F. less active than 
the reference catalyst. These data mean, based on the activities shown in 
Table III, that Catalyst No. 4 was 11.degree. F. less active than Catalyst 
No. 1--the latter differing in composition only by the absence of rare 
earths. 
Catalyst No. 5 was found to be 5.degree. F. more active than the reference 
catalyst. But since its comparable catalyst, i.e., Catalyst No. 2, was 
18.degree. F. more active than the reference catalyst, Catalyst No. 5 was 
13.degree. F. less active than Catalyst No. 2--with, again, the latter 
only differing by the absence of rare earths. 
It will also be seen, from the data just presented in this example, that 
the absence of rare earth elements even provides an advantage in catalysts 
containing an LZ-210 zeolite of silica-to-alumina ratio as low as about 
6.0. Thus, it is a discovery in the present invention that hydrocracking 
catalysts containing non-noble Group VIII metals are highly active for 
hydrocracking with LZ-210 zeolites, and particularly in the preferred 
embodiment wherein such zeolites are hydrothermally treated and 
essentially free of cations containing rare earth metals. 
Although the invention has been described in conjunction with preferred 
embodiments and comparative examples, it is evident that many 
alternatives, modifications, and variations of the invention will be 
apparent to those skilled in the art in light of the foregoing 
description. For example, one may use any of a number of porous refractory 
oxides in conjunction with the LZ-210 zeolite, and the present 
specification only mentions some. Another which should be mentioned is the 
dispersion taught in U.S. Pat. No. 4,517,073, herein incorporated by 
reference in its entirety, which provides for a catalyst useful in the 
production of both midbarrel and gasoline products. Accordingly, it is 
intended in the present invention to embrace all such alternatives, 
modifications, and variations as fall within the spirit and scope of the 
appended claims.