Modified MCM-56, its preparation and use

A layered composition of matter, MCM-56, has an X-ray diffraction pattern including lines at d-spacing values of 12.4.+-.0.2, 9.9.+-.0.3, 6.9.+-.0.1, 6.2.+-.0.1, 3.55.+-.0.07 and 3.42.+-.0.07 Angstroms and has been selectively modified so that the ratio of the number of active acid sites at its external surface to the number of internal active acid sites is greater than that of the unmodified material. When used as an additive to a large pore zeolite catalyst in the catalytic cracking of a petroleum feedstock, the modified MCM-56 gives an improved gasoline yield/octane relationship, an improved coke selectivity and a higher combined gasoline and potential alkylate yield than an identical catalyst containing unmodified MCM-56.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to selectively modified MCM-56, to a method of its 
preparation and to its use as a sorbent and a catalyst component for 
conversion of organic compounds, in particular as a component of a 
catalytic cracking catalyst. 
2. Description of the Prior Art 
MCM-56 is a porous inorganic solid and is described in U.S. Pat. No. 
5,362,697, the entire contents of which are incorporated herein by 
reference. 
Porous inorganic solids have found utility as catalysts and separation 
media for industrial application. The openness of their microstructure 
allows molecules access to the relatively large surface areas of these 
materials that enhance their catalytic and sorptive activity. The porous 
materials in use today can be sorted into three broad categories using the 
details of their microstructure as a basis for classification. These 
categories are the amorphous and paracrystalline supports, the crystalline 
molecular sieves and modified layered materials. The detailed differences 
in the microstructures of these materials manifest themselves as important 
differences in the catalytic and sorptive behavior of the materials, as 
well as in differences in various observable properties used to 
characterize them, such as their surface area, the sizes of pores and the 
variability in those sizes, the presence or absence of X-ray diffraction 
patterns and the detail in such patterns, and the appearance of the 
materials when their microstructure is studied by transmission electron 
microscopy and electron diffraction methods. 
Amorphous and paracrystalline materials represent an important class of 
porous inorganic solids that have been used for many years in industrial 
applications. Typical examples of these materials are the amorphous 
silicas commonly used in catalyst formulations and the paracrystalline 
transitional aluminas used as solid acid catalysts and petroleum reforming 
catalyst supports. The term "amorphous" is used here to indicate a 
material with no long range order and can be somewhat misleading, since 
almost all materials are ordered to some degree, at least on the local 
scale. An alternate term that has been used to describe these materials is 
"X-ray indifferent". The microstructure of the silicas consists of 100-250 
Angstrom particles of dense amorphous silica (Kirk-Othmer Encyclopedia of 
Chemical Technology, 3rd Edition, Vol. 20, John Wiley & Sons, New York, p. 
766-781, 1982), with the porosity resulting from voids between the 
particles. Since there is no long range order in these materials, the 
pores tend to be distributed over a rather large range. This lack of order 
also manifests itself in the X-ray diffraction pattern, which is usually 
featureless. 
Paracrystalline materials such as the transitional aluminas also have a 
wide distribution of pore sizes, but better defined X-ray diffraction 
patterns usually consisting of a few broad peaks. The microstructure of 
these materials consists of tiny crystalline regions of condensed alumina 
phases and the porosity of the materials results from irregular voids 
between these regions (K. Wefers and Chanakya Misra, "Oxides and 
Hydroxides of Aluminum", Technical Paper No. 19 Revised, Alcoa Research 
Laboratories, p. 54-59, 1987). Since, in the case of either material, 
there is no long range order controlling the sizes of pores in the 
material, the variability in pore size is typically quite high. The sizes 
of pores in these materials fall into a regime called the mesoporous 
range, including, for example, pores within the range of about 15 to about 
200 Angstroms. 
In sharp contrast to these structurally ill-defined solids are materials 
whose pore size distribution is very narrow because it is controlled by 
the precisely repeating crystalline nature of the materials' 
microstructure. These materials are called "molecular sieves", the most 
important examples of which are zeolites. 
Zeolites, both natural and synthetic, have been demonstrated in the past to 
have catalytic properties for various types of hydrocarbon conversion. 
Certain zeolitic materials are ordered, porous crystalline 
aluminosilicates having a definite crystalline structure as determined by 
X-ray diffraction, within which there are a large number of smaller 
cavities which may be interconnected by a number of still smaller channels 
or pores. These cavities and pores are uniform in size within a specific 
zeolitic material. Since the dimensions of these pores are such as to 
accept for adsorption molecules of certain dimensions while rejecting 
those of larger dimensions, these materials are known as "molecular 
sieves" and are utilized in a variety of ways to take advantage of these 
properties. 
Such molecular sieves, both natural and synthetic, include a wide variety 
of positive ion-containing crystalline silicates. These silicates can be 
described as a rigid three-dimensional framework of SiO.sub.4 and Periodic 
Table Group IIIB element oxide, e.g., AlO.sub.4, in which the tetrahedra 
are cross-linked by the sharing of oxygen atoms whereby the ratio of the 
total Group IIIB element, e.g., aluminum, and Group IVB element, e.g., 
silicon, atoms to oxygen atoms is 1:2. The electrovalence of the 
tetrahedra containing the Group IIIB element, e.g., aluminum, is balanced 
by the inclusion in the crystal of a cation, for example, an alkali metal 
or an alkaline earth metal cation. This can be expressed wherein the ratio 
of the Group IIIB element, e.g., aluminum, to the number of various 
cations, such as Ca/2, Sr/2, Na, K or Li, is equal to unity. One type of 
cation may be exchanged either entirely or partially with another type of 
cation utilizing ion exchange techniques in a conventional manner. By 
means of such cation exchange, it has been possible to vary the properties 
of a given silicate by suitable selection of the cation. The spaces 
between the tetrahedra are occupied by molecules of water prior to 
dehydration. 
Prior art techniques have resulted in the formation of a great variety of 
synthetic zeolites. Many of these zeolites have come to be designated by 
letter or other convenient symbols, as illustrated by zeolites A (U.S. 
Pat. No. 2,882,243); X (U.S. Pat. No. 2,882,244); Y (U.S. Pat. No. 
3,130,007); ZK-5 (U.S. Pat. No. 3,247,195); ZK-4 (U.S. Pat. No. 
3,314,752); ZSM-5 (U.S. Pat. No. 3,702,886); ZSM-11 (U.S. Pat. No. 
3,709,979); ZSM-12 (U.S. Pat. No. 3,832,449), ZSM-20 (U.S. Pat. No. 
3,972,983); ZSM-35 (U.S. Pat. No. 4,016,245); ZSM-23 (U.S. Pat. No. 
4,076,842); MCM-22 (U.S. Pat. No. 4,954,325); MCM-35 (U.S. Pat. No. 
4,981,663); MCM-49 (U.S. Pat. No. 5,236,575); and PSH-3 (U.S. Pat. No. 
4,439,409). 
Certain layered materials, which contain layers capable of being spaced 
apart with a swelling agent, may be pillared to provide materials having a 
large degree of porosity. Examples of such layered materials include 
clays. Such clays may be swollen with water, whereby the layers of the 
clay are spaced apart by water molecules. Other layered materials are not 
swellable with water, but may be swollen with certain organic swelling 
agents such as amines and quaternary ammonium compounds. Examples of such 
non-water swellable layered materials are described in U.S. Pat. No. 
4,859,648 and include layered silicates, magadiite, kenyaite, trititanates 
and perovskites. Another example of a non-water swellable layered 
material, which can be swollen with certain organic swelling agents, is a 
vacancy-containing titanometallate material, as described in U.S. Pat. No. 
4,831,006. 
Once a layered material is swollen, the material may be pillared by 
interposing a thermally stable substance, such as silica, between the 
spaced apart layers. The aforementioned U.S. Pat. Nos. 4,831,006 and 
4,859,648 describe methods for pillaring the non-water swellable layered 
materials described therein and are incorporated herein by reference for 
definition of pillaring and pillared materials. 
Other patents teaching pillaring of layered materials and the pillared 
products include U.S. Pat. Nos. 4,216,188; 4,248,739; 4,176,090; and 
4,367,163; and European Patent Application No. 205,711. 
The X-ray diffraction patterns of pillared layered materials can vary 
considerably, depending on the degree that swelling and pillaring disrupt 
the otherwise usually well-ordered layered microstructure. The regularity 
of the microstructure in some pillared layered materials is so badly 
disrupted that only one peak in the low angle region on the X-ray 
diffraction pattern is observed, at a d-spacing corresponding to the 
interlayer repeat in the pillared material. Less disrupted materials may 
show several peaks in this region that are generally orders of this 
fundamental repeat. X-ray reflections from the crystalline structure of 
the layers are also sometimes observed. The pore size distribution in 
these pillared layered materials is narrower than those in amorphous and 
paracrystalline materials but broader than that in crystalline framework 
materials. 
MCM-56 (and the related MCM-22) is an unusual material in that it exhibits 
features of both layered and zeolitic materials. Thus MCM-56 has layers 
which are microporous and contain cation-exchangeable acid sites. This 
leads to the presence of acid sites at two different locations; acid sites 
are located on the large external surface of MCM-56 and further acid sites 
are located within the internal pore structure of the layers. These 
further internal acid sites are only accessible through the pore openings 
in the layers which are believed to be elliptical with dimensions of about 
5.9 by 4.0 Angstrom. 
SUMMARY OF THE INVENTION 
According to the present invention, it has now been found that the 
catalytic and sorptive properties of MCM-56 can be significantly altered 
by selectively modifying the material so that the ratio of the number of 
active acid sites at its external surface to the number of internal active 
acid sites is different, and preferably greater, than that of unmodified 
MCM-56. For example, MCM-56 modified so as to selectively increase the 
ratio of its external to internal acid activity has been found to result 
in an unexpected increase in the yield of high value liquid products, such 
as gasoline and distillate, and less bottoms fraction and coke, as 
compared to unmodified MCM-56, when used as an additive to a conventional 
zeolite Y cracking catalyst. 
In one aspect, therefore, the present invention resides in a layered 
composition of matter, MCM-56, which has an X-ray diffraction including 
the lines listed in Table II below and which has been selectively modified 
so that the ratio of the number of active acid sites at its external 
surface to the number of internal active acid sites is greater than that 
of the unmodified material. 
DESCRIPTION OF SPECIFIC EMBODIMENTS 
The layered MCM-56 material of the invention has an X-ray diffraction 
pattern which is distinguished by the combination of line positions and 
intensities from the patterns of other known as-synthesized or thermally 
treated materials as shown below in Table I (as synthesized) and Table II 
(calcined). In these tables, intensities are defined relative to the 
d-spacing line at 12.4 Angstroms. 
TABLE I 
______________________________________ 
MCM-56 
(as-synthesized) 
Interplanar 
d-spacing Relative 
(A) Intensity 
______________________________________ 
12.4 .+-. 0.2 vs 
9.9 .+-. 0.3 m 
6.9 .+-. 0.1 w 
6.4 .+-. 0.3 w 
6.2 .+-. 0.1 w 
3.57 .+-. 0.07 
m-s 
3.44 .+-. 0.07 
vs 
______________________________________ 
TABLE II 
______________________________________ 
MCM-56 (as-calcined) 
Interplanar Relative 
d-Spacing (A) Intensity 
______________________________________ 
12.4 .+-. 0.2 vs 
9.9 .+-. 0.3 m-s 
6.9 .+-. 0.1 w 
6.2 .+-. 0.1 s 
3.55 .+-. 0.07 m-s 
3.42 .+-. 0.07 vs 
______________________________________ 
These X-ray diffraction data were collected with a Scintag diffraction 
system, equipped with a germanium solid state detector, using copper 
K-alpha radiation. The diffraction data were recorded by step-scanning at 
0.02 degrees of two-theta, where theta is the Bragg angle, and a counting 
time of 10 seconds for each step. The interplanar spacings, d's, were 
calculated in Angstrom units (A), and the relative intensities of the 
lines, I/I.sub.o is one-hundredth of the intensity of the strongest line, 
above background, were derived with the use of a profile fitting routine 
(or second derivative algorithm). The intensities are uncorrected for 
Lorentz and polarization effects. The relative intensities are given in 
terms of the symbols vs=very strong (60-100), s=strong (40-60), m=medium 
(20-40) and w=weak (0-20). It should be understood that diffraction data 
listed for this sample as single lines may consist of multiple overlapping 
lines which under certain conditions, such as differences in 
crystallographic changes, may appear as resolved or partially resolved 
lines. Typically, crystallographic changes can include minor changes in 
unit cell parameters and/or a change in crystal symmetry, without a change 
in the structure. These minor effects, including changes in relative 
intensities, can also occur as a result of differences in cation content, 
framework composition, nature and degree of pore filling, and thermal 
and/or hydrothermal history. 
The layered material MCM-56 of this invention has a composition involving 
the molar relationship: 
EQU X.sub.2 O.sub.3 :(n)YO.sub.2, 
wherein X is a trivalent element, such as aluminum, boron, iron and/or 
gallium, preferably aluminum; Y is a tetravalent element such as silicon 
and/or germanium, preferably silicon; and n is less than about 35, e.g. 
from about 5 to less than about 25, usually from about 10 to less than 
about 20, more usually from about 13 to about 18. In the as-synthesized 
form, the material has a formula, on an anhydrous basis and in terms of 
moles of oxides per n moles of YO.sub.2, as follows: 
EQU (0-2)M.sub.2 O:(1-2)R:X.sub.2 O.sub.3 :(n)YO.sub.2 
wherein M is an alkali or alkaline earth metal, and R is an organic moiety. 
The M and R components are associated with the material as a result of 
their presence during synthesis, and are easily removed by post-synthesis 
methods hereinafter more particularly described. 
To the extent desired, the original alkali or alkaline earth, e.g. sodium, 
cations of the as-synthesized MCM-56 can be replaced in accordance with 
techniques well known in the art, at least in part, by ion exchange with 
other cations. Preferred replacing cations include metal ions, hydrogen 
ions, hydrogen precursor, e.g. ammonium, ions and mixtures thereof. 
Particularly preferred cations are those which tailor the catalytic 
activity for certain hydrocarbon conversion reactions. These include 
hydrogen, rare earth metals and metals of Groups IIA, IIIA, IVA, IB, IIB, 
IIIB, IVB and VIII of the Periodic Table of the Elements. 
In the calcined form, MCM-56 exhibits high surface area (greater than 300 
m.sup.2 /gm) and unusually large sorption capacity for certain large 
molecules when compared to previously described materials such as calcined 
PSH-3, SSZ-25, MCM-22, and MCM-49. Thus calcined MCM-56 is characterised 
by a sorption capacity for 1,3,5-trimethylbutane of at least about 35 
.mu.l/gram and an initial uptake of 2,2-dimethylbutane of 15 mg/gram in 
less than about 20 seconds. 
MCM-56 can be prepared from a reaction mixture containing sources of alkali 
or alkaline earth metal (M), e.g. sodium or potassium, cation, an oxide of 
trivalent element X, e.g. aluminum, an oxide of tetravalent element Y, 
e.g. silicon, directing agent (R), and water, said reaction mixture having 
a composition, in terms of mole ratios of oxides, within the following 
ranges: 
______________________________________ 
Reactants Useful Preferred 
______________________________________ 
YO.sub.2 /X.sub.2 O.sub.3 
5 to 35 10 to 25 
H.sub.2 O/YO.sub.2 
10 to 70 16 to 40 
OH.sup.- /YO.sub.2 
0.05 to 0.5 0.06 to 0.3 
M/YO.sub.2 0.05 to 3.0 0.06 to 1.0 
R/YO.sub.2 0.1 to 1.0 0.3 to 0.5 
______________________________________ 
The source of YO.sub.2 should comprise predominantly solid YO.sub.2, for 
example at least about 30 wt. % solid YO.sub.2 in order to obtain the 
crystal product of the invention. Where YO.sub.2 is silica, the use of a 
silica source containing at least about 30 wt. % solid silica, e.g. 
Ultrasil (a precipitated, spray dried silica containing about 90 wt. % 
silica) or HiSil (a precipitated hydrated SiO.sub.2 containing about 87 
wt. % silica, about 6 wt. % free H.sub.2 O and about 4.5 wt. % bound 
H.sub.2 O of hydration and having a particle size of about 0.02 micron) 
favors crystalline MCM-56 formation from the above mixture under the 
synthesis conditions required. Preferably, therefore, the YO.sub.2, e.g. 
silica, source contains at least about 30 wt. % solid YO.sub.2, e.g. 
silica, and more preferably at least about 40 wt. % solid YO.sub.2, e.g. 
silica. 
Directing agent R is selected from the group consisting of cycloalkylamine, 
azacycloalkane, diazacycloalkane, and mixtures thereof, alkyl comprising 
from 5 to 8 carbon atoms. Non-limiting examples of R include 
cyclopentylamine, cyclohexylamine, cycloheptylamine, hexamethyleneimine, 
heptamethyleneimine, homopiperazine, and combinations thereof, with 
hexamethyleneimine being particularly preferred. 
Crystallization of the present layered material can be carried out under 
either static or stirred conditions in a suitable reactor vessel, such as 
for example polypropylene jars or teflon lined or stainless steel 
autoclaves, at a temperature of about 80.degree. C. to about 225.degree. 
C. It is critical, however, in the synthesis of MCM-56 from the above 
reaction mixture to stop and quench the reaction prior to the onset of 
MCM-49 formation at the expense of MCM-56. One method for controlling the 
synthesis to produce the required MCM-56 is disclosed in U.S. Pat. No. 
5,362,697 and involves monitoring the X-ray diffraction pattern in the 
8.8-11.2 Angstrom d-spacing range. MCM-56 is characterized by a broad band 
centered around d-spacing 9.9 Angstroms, whereas MCM-49 exhibits two 
resolved maxima at approximately 8.8-9.2 Angstroms and 10.8-11.2 Angstroms 
with a distinct depression between them. While the band in the 8.8-11.2 
Angstrom d-spacing range for the synthesis mixure may have an asymmetric 
profile, for example with an inflection point, the emergence of a 
depression may be indicative of the onset of MCM-49 formation and the loss 
of MCM-56. 
It should be realized that the reaction mixture components can be supplied 
by more than one source. The reaction mixture can be prepared either 
batchwise or continuously. 
After synthesis is complete, the MCM-56 is separated from the reaction 
mixture and is then conveniently dehydrated and treated to remove the 
organic directing agent. 
Dehydration is generally performed by heating to a temperature in the range 
of 200.degree. C. to about 370.degree. C. in an atmosphere such as air, 
nitrogen, etc. and at atmospheric, subatmospheric or superatmospheric 
pressures for between 30 minutes and 48 hours. Dehydration can also be 
performed at room temperature merely by placing the MCM-56 in a vacuum, 
but a longer time is required to obtain a sufficient amount of 
dehydration. 
Removal of the organic directing agent is generally performed by heating at 
a temperature of at least about 370.degree. C. for at least 1 minute and 
generally not longer than 20 hours. While subatmospheric pressure can be 
employed for the thermal treatment, atmospheric pressure is desired for 
reasons of convenience. The thermal treatment can be performed at a 
temperature up to about 925.degree. C. 
The resultant MCM-56 is subjected to the selective modification procedure 
of the invention so as to alter the ratio of the surface acid activity of 
the material to its internal acid activity. 
One suitable method for selective modification involves a multi-stage ion 
exchange procedure, in which the calcined MCM-56 is initially contacted 
with a catalytically inactive cation, which is capable of occupying all 
the exchange sites, both internal and external, of the MCM-56. Suitable 
cations have dimensions less than the pore windows of MCM-56, which have 
dimensions of 5.9.times.4 Angstrom, and include the sodium cation, the 
potassium cation and the cesium cation. The product is then back-exchanged 
with a bulky cation which replaces the cations on the external surface of 
the MCM-56 but which, by virtue of its size, is sterically hindered from 
entering the pore openings of the material. Suitable bulky cations have at 
least one dimension greater than 6 Angstrom and include the 
tetrapropylammonium (TPA.sup.+) cation, the tetraethylammonium (TEA.sup.+) 
cation and the tetrabutylammonium (TBA.sup.+) cation. 
Another suitable method for-selective modification involves coating the 
external surface of the MCM-56 with a catalytically active or inactive 
material, such as alumina or silica, so as to increase or decrease 
respectively the surface activity compared to the internal activity of the 
MCM-56. 
A convenient method of measuring the surface acidity of MCM-56, exclusive 
of its internal acidity, is to determine its activity for the dealkylation 
of 1,3,5-tri-tertbutylbenzene (TTBB), a bulky molecule that can only react 
with the acid sites on the surface of the material. 
Dealkylation of TTBB is a facile, reproducible method for measuring surface 
acidity of catalysts. External surface activity can be measured exclusive 
of internal activity for zeolites with pore diameters up to and including 
faujasite. As a test reaction dealkylation of TTBB occurs at a constant 
temperature in the range of from about 25.degree. to about 300.degree. C., 
and preferably in the range of from about 200.degree. to about 260.degree. 
C. 
The experimental conditions for the test used herein include a temperature 
of 200.degree. C. and atmospheric pressure. The dealkylation of TTBB is 
carried out in a glass reactor (18 cm.times.1 cm OD) containing an 8 gm 
14/30 mesh Vycor chip preheater followed by 0.1 gm catalyst powder mixed 
with Vycor chips. The reactor is heated to 200.degree. C. in 30 cc/gm 
nitrogen for 30 minutes to remove impurities from the catalyst sample. Ten 
gm/hr of TTBB dissolved in toluene (7% TTBB) is injected into the reactor. 
The feed vaporizes as it passes through the preheater and is vapor when 
passing over the catalyst sample. After equilibrium is reached the 
nitrogen is switched to 20 cc/min hydrogen. The test is then run for about 
30 minutes and the reaction products are analyzed by gas chromatography. 
The major dealkylation product is di-t-butylbenzene (DTBB). Further 
dealkylation to t-butylbenzene (TBB) and benzene (B) occurs but to a 
lesser extent. Conversion of TTBB is calculated on a molar carbon basis. 
Dealkylation product weight % are each multiplied by the appropriate 
carbon number ratio to convert to the equivalent amount of TTBB, i.e. 
DTBB.times.18/14, TBB.times.18/10 and B.times.18/6. These values are then 
used in the following conversion equation where asterisks indicate 
adjustment to the equivalence. 
##EQU1## 
The coefficient of reaction, k.sub.TTBB is then calculated on the 
assumption that that the conversion of TTBB is a first order reaction 
according to the equation: 
##EQU2## 
where .epsilon..sub.TTBB is the fractional conversion of TTBB at 30 
minutes on stream. 
In the case of MCM-56, the TTBB conversion is accompanied by significant 
conversion of toluene by disproportionation into benzene and xylenes. The 
toluene conversion is calculated based on the weight % of toluene in the 
feed converted and, again assuming that the conversion is a first order 
reaction, k.sub.Toluene is derived from: 
##EQU3## 
where .epsilon..sub.Toluene is the fractional conversion of toluene at 30 
minutes on stream. 
A convenient method of measuring the overall acidity of MCM-56, inclusive 
of both its internal and external acidity, is the alpha test, which is 
described in U.S. Pat. No. 3,354,078; in the Journal of Catalysis, Vol. 4, 
p. 527 (1965); Vol. 6, p. 278 (1966); and Vol. 61, p. 395 (1980), each 
incorporated herein by reference as to that description. The experimental 
conditions of the test used herein include a constant temperature of 
538.degree. C. and a variable flow rate as described in detail in the 
Journal of Catalysis, Vol. 61, p. 395. 
Thus the selective modification of the invention can be demonstrated by 
comparing the TTBB conversion and the alpha value of the MCM-56 before and 
after modification. 
The modified MCM-56 material of this invention may be used as an adsorbent, 
such as for separating at least one component from a mixture of components 
in the vapor or liquid phase having differential sorption characteristics 
with respect to MCM-56. Therefore, at least one component can be partially 
or substantially totally separated from a mixture of components having 
differential sorption characteristics with respect to MCM-56 by contacting 
the mixture with the MCM-56 to selectively sorb the one component. 
The modified MCM-56 material of this invention can also be used to catalyze 
a wide variety of chemical conversion processes including many of present 
commercial/industrial importance. When used as a catalyst, the modified 
MCM-56 material of the invention may be intimately combined with a 
hydrogenating component such as tungsten, vanadium, molybdenum, rhenium, 
nickel, cobalt, chromium, manganese, or a noble metal such as platinum or 
palladium where a hydrogenation-dehydrogenation function is to be 
performed. Such component can be in the composition by way of 
cocrystallization, exchanged into the composition to the extent a Group 
IIIA element, e.g. aluminum, is in the structure, impregnated therein or 
intimately physically admixed therewith. Such component can be impregnated 
in or on to it such as, for example, by, in the case of platinum, treating 
the silicate with a solution containing a platinum metal-containing ion. 
Thus, suitable platinum compounds for this purpose include chloroplatinic 
acid, platinous chloride and various compounds containing the platinum 
amine complex. 
When used as a catalyst, it may be desirable to incorporate the modified 
MCM-56 of the invention with another material resistant to the 
temperatures and other conditions employed in organic conversion 
processes. Such materials include active and inactive materials and 
synthetic or naturally occurring zeolites as well as inorganic materials 
such as clays, silica and/or metal oxides such as alumina. The latter may 
be either naturally occurring or in the form of gelatinous precipitates or 
gels including mixtures of silica and metal oxides. Use of a material in 
conjunction with the MCM-56, i.e. combined therewith or present during 
synthesis of MCM-56, which is active, tends to change the conversion 
and/or selectivity of the catalyst in certain organic conversion 
processes. Inactive materials suitably serve as diluents to control the 
amount of conversion in a given process so that products can be obtained 
economically and orderly without employing other means for controlling the 
rate of reaction. These materials may be incorporated into naturally 
occurring clays, e.g. bentonite and kaolin, to improve the crush strength 
of the catalyst under commercial operating conditions. Said materials, 
i.e. clays, oxides, etc., function as binders for the catalyst. It is 
desirable to provide a catalyst having good crush strength because in 
commercial use it is desirable to prevent the catalyst from breaking down 
into powder-like materials. These clay and/or oxide binders have been 
employed normally only for the purpose of improving the crush strength of 
the catalyst. 
Naturally occurring clays which can be composited with the new crystal 
include the montmorillonite and kaolin family, which families include the 
subbentonites, and the kaolins commonly known as Dixie, McNamee, Georgia 
and Florida clays or others in which the main mineral constituent is 
halloysite, kaolinite, dickite, nacrite, or anauxite. Such clays can be 
used in the raw state as originally mined or initially subjected to 
calcination, acid treatment or chemical modification. Binders useful for 
compositing with the present MCM-56 layered material also include 
inorganic oxides, notably alumina. 
In addition to the foregoing materials, the MCM-56 can be composited with a 
porous matrix material such as silica-alumina, silica-magnesia, 
silica-zirconia, silica-thoria, silica-beryllia, silica-titania as well as 
ternary compositions such as silica-alumina-thoria, 
silica-alumina-zirconia silica-alumina-magnesia and 
silica-magnesia-zirconia. 
The relative proportions of finely divided MCM-56 material and inorganic 
oxide matrix vary widely, with the MCM-56 content ranging from about 1 to 
about 90 percent by weight and more usually, particularly when the 
composite is prepared in the form of beads, in the range of about 2 to 
about 80 weight percent of the composite. 
The modified MCM-56 produced according to the invention is particularly 
intended for use as an additive catalyst to a catalytic cracking catalyst. 
Conventional cracking catalysts comprise a primary cracking component, 
which may be amorphous, such as silica/alumina, but more normally 
comprises a large pore crystalline zeolite, such as zeolite X, zeolite Y, 
REY or US-REY, ZSM-20 or zeolite L. In addition, to the large pore 
zeolite, such as zeolite Y, conventional cracking catalysts contain other 
components, notably a matrix for the zeolite. When a matrix is used, the 
content of the large pore zeolite is conveniently about 5 to 50% by weight 
of the matrixed catalyst. 
The modified MCM-56 according to the invention can be added to such a 
conventional cracking catalyst, either as a separate particle, typically 
bound with a separate matrix, or combined with the large pore zeolite as a 
single particle. The amount of modified MCM-56 present in the cracking 
catalyst can vary between 0.5% and 90% by weight, and preferably is 
between 2% and 45% by weight, of the overall cracking catalyst. 
Cracking catalysts containing the modified MCM-56 of the invention are 
useful in both fluid catalytic cracking (FCC) and Thermofor catalytic 
cracking (TCC). Such processes typically operate at temperatures between 
200.degree. C. and 700.degree. C. and under reduced or superatmospheric 
pressure. 
Catalysts containing the modified MCM-56 of the invention can be used to 
crack a wide variety of heavy hydrocarbon feedstocks, such as petroleum 
fractions having an initial boiling point of 200.degree. C., a 50% point 
of at least 260.degree. C. and an end point in excess of 315.degree. C. 
Such hydrocarbon feedstocks include gas oils, residual oils, cycle stocks, 
whole and topped crudes and the heavy hydrocarbon fractions derived from 
the destructive hydrogenation of coal, tar, pitches asphalts and the like. 
According to the invention, it has surprisingly been found that cracking of 
a petroleum feedstock with a catalyst MCM-56 which has been modified to 
increase the ratio of external activity to internal activity gives an 
improved gasoline yield/octane relationship, an improved coke selectivity 
and a higher combined gasoline and potential alkylate yield than an 
identical catalyst containing unmodified MCM-56. 
Examples of other chemical conversion processes which are effectively 
catalyzed by the modified MCM-56 of the invention, by itself or in 
combination with one or more other catalytically active substances 
including other crystalline catalysts, include: 
(1) alkylation of aromatic hydrocarbons, e.g. benzene, with long chain 
olefins, e.g. C.sub.14 olefin, with reaction conditions including a 
temperature of from about 340.degree. C. to about 500.degree. C., a 
pressure of from about atmospheric to about 200 atmospheres, a weight 
hourly space velocity of from about 2 hr.sup.-1 to about 2000 hr.sup.-1 
and an aromatic hydrocarbon/olefin mole ratio of from about 1/1 to about 
20/1, to provide long chain alkyl aromatics which can be subsequently 
sulfonated to provide synthetic detergents; 
(2) alkylation of aromatic hydrocarbons with gaseous olefins to provide 
short chain alkyl aromatic compounds, e.g. the alkylation of benzene with 
propylene to provide cumene, with reaction conditions including a 
temperature of from about 10.degree. C. to about 125.degree. C., a 
pressure of from about 1 to about 30 atmospheres, and an aromatic 
hydrocarbon weight hourly space velocity (WHSV) of from 5 hr.sup.-1 to 
about 50 hr.sup.-1 ; 
(3) alkylation of reformate containing substantial quantities of benzene 
and toluene with fuel gas containing C.sub.5 olefins to provide, inter 
alia, mono- and dialkylates with reaction conditions including a 
temperature of from about 315.degree. C. to about 455.degree. C., a 
pressure of from about 400 to about 800 psig, a WHSV-olefin of from about 
0.4 hr.sup.-1 to about 0.8 hr.sup.-1, a WHSV-reformate of from about 1 
hr.sup.-1 to about 2 hr.sup.-1 and a gas recycle of from about 1.5 to 2.5 
vol/vol fuel gas feed; 
(4) alkylation of aromatic hydrocarbons, e.g., benzene, toluene, xylene and 
naphthalene, with long chain olefins, e.g. C.sub.14 olefin, to provide 
alkylated aromatic lube base stocks with reaction conditions including a 
temperature of from about 160.degree. C. to about 260.degree. C. and a 
pressure of from about 350 to 450 psig; 
(5) alkylation of phenols with olefins or equivalent alcohols to provide 
long chain alkyl phenols with reaction conditions including a temperature 
of from about 200.degree. C. to about 250.degree. C., a pressure of from 
about 200 to 300 psig and a total WHSV of from about 2 hr.sup.-1 to about 
10 hr.sup.-1 ; and 
(6) alkylation of isoalkanes, e.g. isobutane, with olefins, e.g. 2-butene, 
with reaction conditions including a temperature of from about -25.degree. 
C. to about 400.degree. C., e.g., from 75.degree. C. to 200.degree. C., a 
pressure of from below atmospheric to about 35000 kPa.(5000 psig), e.g. 
from 100 to 7000 kPa (1 to 1000 psig), a weight hourly space velocity 
based on olefin of from about 0.01 hr.sup.-1 to about 100 hr.sup.-1, e.g. 
from 0.1 hr.sup.-1 to 20 hr.sup.-1, and a mole ratio of total isoalkane to 
total olefin of from about 1:2 to about 100:1, e.g. from 3:1 to 30:1. 
In order to more fully illustrate the nature of the invention and the 
manner of practicing same, the following examples are presented.

EXAMPLE 1 
This example demonstrates the preparation of the hydrogen form of MCM-56. 
A sample of as-synthesized MCM-56 prepared as described in U.S. Pat. No. 
5,362,697 was ammonium exchanged and was dried at 250.degree. F. 
(120.degree. C.) overnight. The dried ammonium exchanged MCM-56 was first 
heated in flowing nitrogen at 900.degree. F. (480.degree. C.) for 3 hours 
to decompose the directing agent followed by calcining in flowing air at 
1000.degree. F. (540.degree. C.) for 6 hours. The resulting MCM-56 sample 
was in the H!-form and was designated as sample A. The properties of 
sample A are listed in Table III below. 
EXAMPLE 2 
This example discloses the preparation of selective cation exchanged 
MCM-56. 
529 g of sample A from Example 1 was slurried in 2650 ml of a 1N NaCl 
solution for 2 hours. The sample was filtered and washed with deionized 
water. The filter cake was re-slurried in 2650 ml of 1N NaCl solution for 
2 hours, and was filtered and washed. The filtercake was dried at 
250.degree. F. overnight. The dried MCM-56 sample was in the Na!-form and 
was designated as sample B. The properties of sample B are listed in Table 
III below. 
600 g of sample B was slurried in 6 liter of 35% tetrapropylammonium 
bromide (TPA!Br) solution for 2 hours. The sample was filtered and washed 
with deionized water until no residual bromide was detected in the 
filtrate. The filtercake was re-slurried in another 6 liter of 35% 
tetrapropylammonium bromide solution for another 2 hours. After filtering 
and washing with deionized water, the filtered cake was dried at 
250.degree. F. (120.degree. C.) overnight. The dried MCM-56 sample was in 
the TPA!/Na!-form and was designated as sample C. The properties of 
sample C are listed in Table III below. 
The selective ion exchange process described above involved the use of a 
small cation, sodium Na!.sup.+, to occupy all exchange (acid) sites in 
MCM-56. The sodium cations on the sample were then back exchanged with a 
bulky cation, tetrapropylammonium, TPA!.sup.+. Due to the bulky dimension 
of TPA!.sup.+ cation, it was selectively exchanged with the sodium 
cations located on the external surface of MCM-56. For those exchange 
(acid) sites located within the layer, they remained occupied with sodium 
because the TPA!.sup.+ cations were too large to access through the 
10-ring pore openings of MCM-56 during the second exchange. 
EXAMPLE 3 
This example discloses the preparation of "alumina-coated" MCM-56. 
A 1852 g of sample A from Example 1 was slurried in 9 liters of 1N ammonium 
nitrate solution for 1 hour. The slurry was filtered and washed with 
deionized water. The filter cake was dried at 250.degree. F. (120.degree. 
C.) overnight. 
An alum solution was prepared by adding 112.5 g of deionized water to 1406 
g of aluminum sulfate (8 wt. % Al.sub.2 O.sub.3) solution. The density of 
the diluted alum solution is 1.38 g/ml. A sodium aluminate solution was 
prepared by adding 886 g of sodium aluminate (USALCO 45) to 39.8 g of 
caustic soda. The density of the sodium aluminate solution is 1.54 g/ml. A 
second sodium aluminate solution was also prepared using the same 
procedure. 
The dried filtercake (845 g) was first slurried in deionized water, and the 
slurry was heated up to 120.degree. F. (50.degree. C.). After the 
temperature of the slurry equilibrated at 120.degree. F. (50.degree. C.), 
the alum solution and the first sodium aluminate solution were introduced 
to the slurry simultaneously by using two separate pumps. The pH of the 
slurry was maintained at pH 7.4-7.6 by adjusting the flow rate of the 
sodium aluminate solution. After completing the addition of the two 
solutions, the slurry was allowed to stir at 120.degree. F. (50.degree. 
C.) for an additional 10 minutes. The second sodium aluminate solution was 
then introduced to the slurry. The final pH of the slurry was allowed to 
stabilize at 9.8-10.0 at 120.degree. F. (50.degree. C.). The slurry was 
stirred at 120.degree. F. (50.degree. C.) for an additional 30 minutes, 
and was filtered and washed with hot deionized water. The filtercake was 
further washed with deionized water until the pH of the filtrate was below 
9. The filtercake was dried at 250.degree. F. (120.degree. C.) overnight. 
The dried filter cake was ammonium exchanged and was calcined at 
1000.degree. F. (540.degree. C.) for 3 hours. The calcined sample was the 
"alumina-coated" MCM-56 and was designated as sample D. 
The properties of sample D are listed in Table III below. 
TABLE III 
______________________________________ 
Sample I.D. 
A B C D 
Example 1 2 2 3 
______________________________________ 
Form H! Na! TPA!/Na! 
Alumina-coated 
SiO.sub.2, wt % 
84.8 82 70 49.2 
Al.sub.2 O.sub.3, wt % 
8 9 6 39 
Na, wt % 0.038 4.63 0.926 0.041 
N, wt % -- -- 1.2 -- 
Ash, % 94.5 88.5 79.5 96 
Alpha* 121 0.7 39 94 
TTBB Test 
K.sub.TTBB, s.sup.-1 
0.24 0.0 3.07 5.02 
K.sub.toluene, s.sup.-1 
0.95 N/a 0.08 0.06 
n-C.sub.6, wt % (@90.degree. C.) 
5.03 3.49 4.89 2.57 
Na/Al (atomic 
0.01 1.14 0.27 &lt;0.01 
ratio) 
(Na + N)/Al -- -- 1.0 -- 
(atomic ratio) 
______________________________________ 
*The alpha measurments were conducted on the samples after calcination at 
1000.degree. F. (540.degree. C.). For sample C, it was first calcined in 
nitrogen at 900.degree. F. (480.degree. C.) to decompose the TPA!.sup.+ 
cations followed by air calcining at 1000.degree. F. (540.degree. C.). 
Table III shows that after sodium exchange, all exchange sites in MCM-56 
(Sample B) were occupied by sodium cations, as indicated by a Na/Al ratio 
of 1.14. After the TPA!Br exchange (Sample C), approximately 73% of the 
exchange sites were not occupied by sodium cations, as indicated by a 
Na/Al ratio of 0.27. The results of the alpha measurements were also 
consistent with the elemental analyses. As all the exchange (acid) sites 
were occupied with sodium cations, sample B exhibited insignificant alpha 
cracking activity. In contrast, sample C demonstrated an alpha value of 
39, consistent with only part of the exchange (acid) sites still being 
occupied by sodium cations. For sample D, although the alpha value was 
only 94 (less than the alpha value of sample A), comparison of the 
n-C.sub.6 uptake at 90.degree. C. of samples A and D indicates that the 
MCM-56 content of sample D was only about 51% by weight. 
Table III also shows that the catalytic properties of sample A were 
dominated by the conversion of toluene which mostly occurred at the 
internal acid sites. The conversion of TTBB with sample A was an order of 
magnitude smaller than those of sample C and D. The conversion of TTBB in 
the presence of toluene demonstrated the unique catalytic properties of 
the modified MCM-56 of samples C and D. Both samples C and D showed a high 
TTBB conversion but with a minimum conversion of toluene, which is 
consistent with the internal acid sites being blocked by sodium or with 
the accessability to the internal acid sites being limited by the alumina 
coating. Sample B exhibited no conversion of TTBB or toluene since all 
acid sites were occupied by sodium. 
EXAMPLE 4 
This example demonstrates the preparation of rare earth exchanged USY. 
A commercial USY, Z14US (Grace Davison), was ammonium exchanged. 4300 g of 
dried ammonium exchanged USY was slurried in 10.8 liter of deionized 
water. A rare earth chloride solution containing 844 g of 
RECl.sub.3.7H.sub.2 O was added to the USY slurry. After completing the 
addition of the rare earth chloride solution, the slurry was stirred under 
ambient conditions overnight. The slurry was filtered and the filtercake 
was washed with deionized water until no chloride was detected in the 
filtrate. The filter cake was dried at 250.degree. F. (120.degree. C.) 
overnight and calcined at 1000.degree. F. (540.degree. C.)for 3 hours. 
This calcined sample was designated as sample E. Elemental analyses of 
sample E are listed below: 
______________________________________ 
RE.sub.2 O.sub.3, wt % 
5.73 
Na, wt % 0.489 
Al.sub.2 O.sub.3, wt % 
22.1 
SiO.sub.2, wt % 
65.5 
Unit cell size .ANG. 
24.595 
Ash, % 96.5 
______________________________________ 
EXAMPLE 5 
Three catalysts, designated catalysts G, H and I, were formulated with 20% 
rare earth exchanged USY (sample E) and 20% unmodified or modified MCM-56 
using samples A, C, and D respectively in a 25% silica/35% clay matrix 
according to the following procedure. 
932 g of ball milled rare earth exchanged USY slurry (32.2% solid) was 
introduced to 1103 g of colloidal silica (Nalco 1034A). The zeolite-silica 
slurry was mixed for at least 3 minutes. A 1282 g of ball milled modified 
or unmodified MCM-56 slurry (23.4% solid) was added to the zeolite-silica 
mixture and mixed for at least 3 minutes. 875 g of kaolin clay (Thiele 
RC-32) was then added to the mixture. Additional deionized water was added 
for satisfactory operation of the spray dryer. The pH of the slurry was 
maintained at pH 3.5-3.75. 
The slurry was spray dried in a Bowen Engineering 2' diameter spray dryer 
with an outlet temperature of 350.degree. F. (180.degree. C.). The 
collected fluid catalyst was washed with deionized water and filtered. The 
wet cake was dried at 250.degree. F. (120.degree. C.) overnight. The dried 
product was first calcined in air at 1000.degree. F. (540.degree. C.) for 
2 hours followed by steam deacitvation at 1450.degree. F. (790.degree. C.) 
in 45% steam/55% air, 0 psig (100 kPa) for 10 hours before catalytic 
testing. Table IV lists the properties of catalysts G, H and I. 
EXAMPLE 6 
A further catalyst, designated catalyst F, was formulated with 20% rare 
earth exchanged USY (sample E) in a 25% silica-55% clay matrix according 
to the following procedure: 
932 g of ball milled rare earth exchanged USY slurry (32.2% solid) was 
introduced to 1103 g of colloidal silica (Nalco 1034A). The zeolite-silica 
slurry was mixed for at least 3 minutes. 1323 g of kaolin clay (Thiele 
RC-32) was then added to the mixture. Additional deionized water was added 
for satisfactory operation of the spray dryer. The pH of the slurry was 
maintained at pH 3.5-3.75. 
The slurry was spray dried in a Bowen Engineering 2' diameter spray dryer 
with an outlet temperature of 350.degree. F. (180.degree. C.). The 
collected fluid catalyst was washed with deionized water and filtered. The 
wet cake was dried at 250.degree. F. (120.degree. C.) overnight. The dried 
product was first calcined in air at 1000.degree. F. (540.degree. C.) for 
2 hours followed by steam deacitvation at 1450.degree. F. (790.degree. C.) 
in 45% steam/55% air, 0 psig (100 kPa) for 10 hours before catalytic 
testing. Table IV lists the properties of catalyst F. 
TABLE IV 
______________________________________ 
Catalyst 
Formulation F G H I 
______________________________________ 
*RE-USY, wt % 
20 20 20 20 
MCM-56 sample type 
None Sample A Sample C 
Sample D 
Clay matrix, wt % 
55 35 35 35 
Silica matrix, wt % 
25 25 25 25 
SiO.sub.2, wt % 
65.2 73.3 72.1 66.4 
Al.sub.2 O.sub.3, wt % 
28.3 21.3 21.3 27.5 
Na, wt % 0.10 0.12 0.32 0.11 
RE.sub.2 O.sub.3, wt % 
1.2 0.98 1.10 1.05 
Clay, wt % 55 35 35 35 
Silica, wt % 25 25 25 25 
Surface area, m.sup.2 /g 
134 185 197 163 
Ash, % 98.6 99.4 98.0 99.2 
______________________________________ 
The results of the rare earth analyses on the four catalysts suggest that 
they have similar RE-USY content in each of the catalyst prepared. The 
results of the surface area measurements of the four steamed catalysts are 
consistent with the relative amount of MCM-56 in each of the catalyst. 
EXAMPLE 7 
Each of the catalysts F, G, H, and I was evaluated in a fixed fluidized bed 
reactor using a Joliet sour heavy gas oil (JSHGO) as a petroleum 
feedstock. The properties of the feedstock are listed in Table V below: 
TABLE V 
______________________________________ 
Feed JHSGO 
______________________________________ 
API gravity 19.7 
Pour Point, .degree.F. (.degree.C.) 
95 (35) 
Kinematic Viscosity at 100 C., cs 
7.95 
Molecular weight 369 
CCR, wt % 0.56 
Aromatics, wt % 55.3 
Saturates, wt % 44.7 
Sulfur, wt % 2.6 
Total nitrogen, ppm 1500 
Basic nitrogen, ppm 490 
Ni, ppm 0.48 
V, ppm 0.29 
Fe, ppm 1.2 
Initial boiling point, .degree.F. (.degree.C.) 
497 (258) 
50% point, .degree.F. (.degree.C.) 
826 (441) 
90% point, .degree.F. (.degree.C.) 
1001 (583) 
______________________________________ 
The reactor temperature was 960.degree. F. (515.degree. C.), and the oil 
delivery time was 1 minute. At a cat-to-oil ratio of 4, the activity 
ranking based on the volume percent conversion of fresh feed was as 
follows: 
EQU H&lt;G.apprxeq.I&lt;F 75&lt;73.2.apprxeq.73.5&lt;71.1 
Comparing the activity of catalyst F with those of catalyst G, H, and I, 
the presence of unmodified or modified MCM-56 helped to increase the 
conversion of a RE-USY containing catalyst. It is also surprising to note 
that catalyst H was the most active among the four catalysts as part of 
the acid sites on MCM-56 were occupied by sodium (ref, Sample C, Example 
2). The similar conversions observed for catalyst G and I suggest that the 
alumina coating on MCM-56 enhanced its activity, as there was only 
approximately .sup..about. 50% MCM-56 in the alumina-coated MCM-56 sample 
(ref. Sample D, Example 3). 
The yield pattern of catalysts F, G, H, and I at 70 vol. % conversion is 
given in Table VI below: 
TABLE VI 
______________________________________ 
Catalyst 
F G K I 
______________________________________ 
Light gas, wt % 3.0 2.9 2.8 2.9 
H.sub.2, wt % 0.14 0.10 0.06 0.12 
Total C.sub.3, vol. % 
7.9 11.1 9.6 9.4 
C.sub.3 =/C.sub.3, mol/mol 
2.3 3.0 3.2 3.3 
Total C.sub.4, vol. % 
13.7 18.0 15.1 16.1 
C.sub.4 =/C.sub.4, mol/mol 
0.7 0.8 0.7 0.8 
C.sub.5.sup.+ Gasoline, vol % 
55.6 50.6 55.2 54.2 
C.sub.5.sup.+ Gasoline, wt % 
45.1 41.0 45.2 44.0 
LCO, wt % (430-740.degree. F.) 
26.4 26.7 26.4 26.6 
HFO, wt % (740+.degree. F.) 
6.3 6.2 6.3 6.2 
Coke, wt % 6.2 5.7 4.5 5.0 
RON, C.sub.5.sup.+ Gasoline 
88.5 91.0 89.0 90.1 
Isobutane/(C.sub.3 + C.sub.4) Olefins 
0.60 0.54 0.54 0.49 
Iso-C.sub.4 =/C.sub.4 = 
0.19 0.29 0.27 0.26 
(Gasoline + LCO)/(HFO + Coke) 
5.7 5.7 6.6 6.3 
Potential alkylate, % vol. 
18.3 26.7 22.8 24.4 
Gasoline + Potential 
73.9 77.3 77.9 78.6 
alkylate, % vol. 
.DELTA.RON/.DELTA.Gasoline loss (vol %) 
Base 0.5 1.3 1.1 
______________________________________ 
The incorporation of unmodified or modified MCM-56 into a RE-USY containing 
catalyst improved the coke selectivity, the octane of the gasoline, and 
the LPG yield. However, the latter came at an expense of the gasoline 
yield loss. 
The modification of MCM-56 by the selective cation exchange method and its 
incorporation in a RE-USY containing catalyst (Catalyst H) resulted in a 
reduction in the gasoline yield loss. Although the absolute gasoline 
octane gain was less than that observed for Catalyst G, the (.DELTA.RON 
/.DELTA.Gasoline loss) ratio suggests that Catalyst H was more effective 
in increasing RON without a significant debit in gasoline yield. Table 5 
shows that Catalyst G and H had (.DELTA.RON/ .DELTA.Gasoline loss) ratios 
of 0.5 and 1.3, respectively. When "alumina-coated" MCM-56 was 
incorporated into a RE-USY containing catalyst (catalyst I), it offered 
similar benefits in the yield pattern of the cracked products to those of 
the catalyst containing the selective exchanged MCM-56 and RE-USY 
(catalyst H). Furthermore, the former yielded a higher octane gasoline 
than that of catalyst H, and had the highest combined gasoline and 
potential alkylate yield among the four catalysts at about 50% less MCM-56 
than catalysts G and H. 
Both catalysts H and I exhibited better bottom upgrading capabilities than 
catalysts F and G, as determined by the (Gasoline+LCO)/(HFO+Coke) ratios. 
Therefore, using modified MCM-56 in the catalytic cracking of petroleum 
feedstock should produce more high value liquid products, such as gasoline 
and distillate, and less bottoms fraction and coke.