Para-selective alkylation catalysts and processes

A method is provided for preparing a para-selective, zeolite-based aromatics alkylation catalyst by treating a ZSM-5 type zeolite base catalyst composite with an aqueous magnesium nitrate solution and thereafter calcining the composite so treated. Such catalysts can be used in alkylation processes to provide alkylated aromatic product mixtures having exceptionally high concentrations of the para-dialkylbenzene isomer.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to preparation of improved zeolite-based catalysts 
especially useful for promoting the alkylation of mono-alkyl aromatic 
compounds to form a dialkyl substituted aromatic product enriched in the 
para (i.e., 1,4-)dialkyl benzene isomer. The invention also relates to a 
process for the alkylation, e.g., ethylation, of monoalkyl aromatic 
compounds, e.g. toluene or ethylbenzene, in a manner so as to maximize the 
production of the product para-isomer, to minimize the production of the 
product meta isomer and to substantially eliminate the production of the 
product ortho isomer. 
2. Description of the Prior Art 
Zeolite-containing compositions are well known catalysts for promoting 
conversion of aromatic hydrocarbons to dialkyl substituted aromatic 
compounds via alkylation, transalkylation, disproportionation and 
isomerization reactions. Numerous techniques are also known for modifying 
zeolite-based aromatics conversion catalysts of this type in order to 
provide catalysts which promote production of a reaction product which is 
enriched in the para-isomer of the desired disubstituted aromatic 
material. For example, Kaeding, U.S. Pat. No. 4,117,024, Issued Sept. 26, 
1978 and assigned to Mobil Oil Corporation, the assignee of the instant 
invention, discloses a process for the conversion of toluene and/or ethyl 
benzene to its corresponding para ethyl alkylation product by carrying out 
the alkylation in the presence of hydrogen and using as a catalyst a 
crystalline aluminosilicate zeolite of specified acidity, sorption 
characteristics and Constraint Index. U.S. Pat. No. 4,117,024 discloses 
many materials which exemplify this genus of catalysts including, but not 
limited to, ZSM-5, ZSM-11, ZSM-12, ZSM-35, and ZSM-38. The patent also 
discloses that the zeolite material may be modified in one or more ways to 
improve the para-selectivity properties of the catalyst. This U.S. Pat. 
No. 4,117,024 is incorporated herein in its entirety by reference as 
setting forth applicable prior art relative to this invention. 
Additionally, reference is further made to Kaeding and Young, U.S. Pat. No. 
4,034,053, Issued July 5, 1977; Kaeding, U.S. Pat. No. 4,049,573, Issued 
Sept. 20, 1977; and Kaeding and Young, U.S. Pat. No. 4,086,287, Issued 
Apr. 25, 1978. All of these patents are also incorporated herein by 
reference in their entirety as setting forth additional applicable prior 
art involving the modification of zeolite based catalysts of this same 
general type in order to improve the para-selectivity characteristics 
thereof when such materials are used to promote various aromatic 
hydrocarbon conversion reactions, including alkylation of monoalkyl 
substituted aromatics to produce dialkylbenzene compounds. 
Considering all of such prior art references together, a process has been 
designed for the commercial production of para-ethyltoluene by the 
catalytic ethylation of toluene with ethylene using cofed hydrogen. Such a 
process utilizes what was heretofore believed to be the best catalyst for 
maximizing para-isomer, minimizing meta-isomer, eliminating ortho isomer, 
providing high conversion of reactants to products and permitting low 
catalyst aging rate. This optimized prior art catalyst is a crystalline 
siliceous material of ZSM-5 topology, as characterized by significant 
x-ray diffraction pattern lines, which is composited with a binder and is 
then impregnated with both phosphorus and magnesium. This selected 
catalyst is made by a series of process steps comprising: preparing the 
siliceous crystalline zeolite; binding the zeolite with a matrix material, 
suitably alumina; steaming the resulting zeolite-containing composite; 
impregnating the composite with diammonium phosphate followed by 
filtering, drying and calcining the resulting phosphorus-impregnated 
composite; contacting the P-containing composite in a first magnesium 
impregnation stage with a magnesium acetate solution, followed by 
calcination; thereafter contacting the composite, in a second separate 
magnesium impregnation stage, with another batch of magnesium acetate 
solution, followed again by calcination to prepare the final from 
catalyst. The modified zeolite catalyst produced in this manner is well 
suited to use in the toluene ethylation process. As can be seen from the 
data presented in the referenced U.S. Pat. No. 4,117,024, an ethyl toluene 
product is thus produced having desirable isomeric distribution 
characteristics, with very advantageous catalyst life and conversion 
capability. 
From the foregoing preparation description and referenced data, it can be 
seen that the prior art catalyst selected as the best for 
commercialization, i.e. a magnesium and phosphorus impregnated, 
alumina-bound zeolite material, achieves its best selectivity for ethylene 
alkylation of toluene to para-ethyltoluene at impregnant loadings of 7 and 
3 weight percent respectively for magnesium and phosphorus, provided the 
catalyst composite into which these materials are impregnated is 
presteamed. Without wishing to be bound by theory, it is believed that the 
magnesium being impregnated onto such a catalyst can have a significant 
affinity for the binder portion of the catalyst composite. It is further 
believed that the initial treatment of the prior art catalyst composite 
with the phosphorus impregnant serves to "passivate" the binder material, 
thereby promoting greater association of magnesium with the zeolite 
portion of the composite upon subsequent treatment of the composite with 
the magnesium acetate solution. Since it is expected that it is magnesium 
associated with the zeolite material in such composite which provides the 
excellent selectivity characteristics of such prior art composites for 
production of para-ethyltoluene, the phosphorus followed by magnesium 
treatment of such composites serves to provide highly desirable toluene 
alkylation catalysts. 
Notwithstanding the suitability of such prior art Mg-P-ZSM-5 type zeolite 
catalyst composites for use in the commercial-scale production of 
para-ethyltoluene, there are still several disadvantages associated with 
the large scale preparation of catalysts of this type in the manner 
described. For example, if the impregnated catalyst is not presteamed, 
para-ethyltoluene selectivity may not be as high as needed for some 
commercial production operations. Furthermore, magnesium impregnation 
concentration to the optimum 7 weight percent cannot generally be achieved 
during commercial scale catalyst production, when using a magnesium 
acetate impregnant solution, in a single impregnation. Multiple 
impregnations, with intermediate calcination, are usually required during 
commercial scale production to achieve the requisite 7% concentration of 
magnesium. Still further, even to achieve this result using multiple 
impregnations, it is necessary to use very concentrated aqueous magnesium 
acetate solutions, e.g. about 50 to 60 weight percent in water. Such 
solutions are very viscous and thus have to be utilized as impregnants at 
elevated temperatures, e.g. about 150.degree. F., in order to reduce 
impregnant viscosity to acceptable impregnation levels. 
All of the foregoing recited disadvantages of the previously selected 
optimum magnesium/phosphorus based alkylation catalyst composites should 
not be taken to in any way mean that such a catalyst was or is 
unsatisfactory. Quite to the contrary, such a prior catalyst is excellent, 
far superior to it predecessors and is quite well suited to use in the 
aromatics alkylation processes described. It is furthermore commercially 
manufacturable, albeit with some difficulty and expense. Notwithstanding 
the suitability of such prior art alkylation catalysts, there is 
nevertheless a continuing need to develop additional catalysts, catalyst 
preparation procedures and alkylation processes employing such catalysts 
which provide one or more performance or commercial advantages over 
similar catalysts, procedures and processes of the prior art. 
Accordingly, it is an object of the present invention to provide an 
additional type of zeolite-based catalyst composite suitable for promoting 
the para-selective conversion of monoalkyl aromatics such as toluene to 
dialkylbenzene materials such as para-ethyltoluene. It is a further object 
of the present invention to provide such an additional type of alkylation 
catalyst which is substantially phosphorus-free but which nevertheless 
exhibits selectivity and activity characteristics comparable or superior 
to those of the hereinbefore described magnesium phosphorus alkylation 
catalysts of the prior art. It is further an object of the present 
invention to provide such an additional type of alkylation catalyst which, 
in comparison with preferred prior art catalysts is simpler and easier to 
manufacture via a novel method for catalyst preparation. It is a further 
object of the present invention to provide an aromatics alkylation process 
employing such an improved zeolite-based alkylation catalyst. 
SUMMARY OF THE INVENTION 
The present invention relates primarily to a method for preparing a novel 
improved phosphorus-free aromatics alkylation catalyst. This catalyst 
preparation method involves the essential steps of preparing a 
zeolite-containing base catalyst composite, contacting this base catalyst 
composite, preferably in a single stage operation, with an aqueous 
solution of a single selected impregnating compound, magnesium nitrate, 
and thereafter calcining the magnesium nitrate treated catalyst composite 
to form the desired aromatics alkylation catalyst. 
The zeolite material used to form the base catalyst composite is a 
siliceous crystalline zeolite having a silica to alumina molar ratio of at 
least about 12, a Constraint Index within the approximate range of 1 to 12 
and a zeolite crystal having a major dimension of from about 1 to 10 
microns and a minor dimension of from about 0.2 to 4 microns. Such 
materials are exemplified by the zeolites ZSM-5, ZSM-11, ZSM-12, ZSM-23, 
ZSM-35, ZSM-38, and ZSM-48. The zeolite material is combined with an 
inorganic oxide binder or matrix material to form a catalyst composite 
comprising from about 1 to 99% by weight of the zeolite and from about 1 
to 99% by weight of the binder. 
The magnesium nitrate impregnation step is conducted under conditions and 
for a length of time suitable to incorporate from about 25% to 50% by 
weight of magnesium nitrate on to the base catalyst composite on an 
anhydrous basis. Since magnesium nitrate is the only catalyst modifier 
utilized, there need be no contact of the catalyst composite with any 
solutions of phosphorus compounds, and the resulting catalyst is therefore 
substantially phosphorus free. 
The calcination step which renders the catalyst ready for use is carried 
out in a nitrogen or oxygen-containing atmosphere at a temperature of from 
about 200.degree. C. to 565.degree. C. Such calcination is conducted for a 
time sufficient to provide a ready-to-use alkylation catalyst that 
contains from about 4% to 8% by weight of magensium which is present in 
the catalyst at least in part as magnesium oxide. 
The resulting magnesium impregnated, substantially phosphorus free zeolite 
composite can be suitably employed to promote alkylation (e.g., 
ethylation) of mono-alkyl aromatics such as toluene to produce a 
dialkylbenzene product mixture enriched in the para-dialkylisomer, e.g. 
ethyltoluene mixtures enriched in para-ethyltoluene. 
DETAILED DESCRIPTION OF THE INVENTION 
In accordance with the present invention, base catalyst composites 
comprising a particular type of zeolite material are modified to provide 
catalysts which are especially useful for promoting para-selective 
alkylation of monoalkyl benzene compounds. The siliceous crystalline 
zeolites used in such base catalyst composites are members of a special 
class of zeolites that exhibits unusual properties. Although such zeolites 
have usually low alumina contents, i.e. high silica to alumina mole 
ratios, they are very active even when the silica to alumina mole ratio 
exceeds 30. Such activity is surprising, since catalytic activity is 
generally attributed to framework aluminum atoms and/or cations associated 
with these aluminum atoms. These zeolites retain their crystallinity for 
long periods in spite of the presence of steam at high temperature which 
induces irreversible collapse of the framework of other zeolites, e.g. of 
the X and A type. Furthermore, carbonaceous deposits, when formed, may be 
removed by burning at higher than usual temperatures to restore activity. 
These zeolites, used as catalysts, generally have low coke-forming 
activity and therefore are conducive to long times on stream between 
regenerations by burning carbonaceous deposits with oxygen-containing gas 
such as air. 
An important characteristic of the crystal structure of this particular 
class of zeolites is that it provides a selective constrained access to 
and egress from the intracrystalline free space by virtue of having an 
effective pore size intermediate between the small pore Linde A and the 
large pore Linde X, i.e. the pore windows of the structure are of about a 
size such as would be provided by 10-membered rings of silicon atoms 
interconnected by oxygen atoms. It is to be understood, of course, that 
these rings are those formed by the regular disposition of the tetrahedra 
making up the anionic framework of the crystalline zeolite, the oxygen 
atoms themselves being bonded to the silicon or aluminum atoms at the 
centers of the tetrahedra. Briefly, the preferred type siliceous 
crystalline zeolites useful in this invention possess, in combination: a 
silica to alumina mole ratio of at least about 12; and a structure 
providing constrained access to the intracrystalline free space. 
The silica to alumina mole ratio referred to may be determined by 
conventional analysis. This ratio is meant to represent, as closely as 
possible, the ratio in the rigid anionic framework of the zeolite crystal 
and to exclude aluminum in the binder or in cationic or other form within 
the channels. Although zeolites with a silica to alumina mole ratio of at 
least 12 and preferably at least 30 are useful in the base catalyst 
composites of the present invention, it is also preferred in some 
instances to use zeolites having substantially higher silica/alumina 
ratios, e.g., 1600 and above. In addition, zeolites as otherwise 
characterized herein but which are substantially free of aluminum, that is 
zeolites having silica to alumina mole ratios of up to infinity, are found 
to be useful and even preferable in some instances. Such "high silica" or 
"highly siliceous" zeolites are intended to be included within this 
description. Thus, also to be included within the zeolite definition are 
substantially pure silica forms of the useful zeolites described herein, 
that is to say those zeolites having no measurable amount of aluminum 
(silica to alumina mole ratio of infinity) but which otherwise embody the 
characteristics disclosed. 
Members of this particular class of zeolites, after activation, acquire an 
intracrystalline sorption capacity for normal hexane which is greater than 
that for water, i.e. they exhibit "hydrophobic" properties. The zeolites 
useful in the catalyst composites of this invention have an effective pore 
size such as to freely sorb normal hexane. In addition, the structure must 
provide constrained access to larger molecules. It is sometimes possible 
to judge from a known crystal structure whether such constrained access 
exists. For example, if the only pore windows in a crystal are formed by 
8-membered rings of silicon and aluminum atoms, then access by molecules 
of larger cross-section than normal hexane is excluded and the zeolite is 
not of the desired type. Windows of 10-membered rings are preferred, 
although in some instances excessive puckering of the rings or pore 
blockage may render these zeolites ineffective. Twelve-membered rings 
usually do not offer sufficient constraint to produce the advantageous 
conversions, although the puckered 12-ring structure of TMA offretite 
shows constrained access. Other 12-ring structures may exist which may be 
operative. 
Rather than attempt to judge from crystal structure whether or not a 
zeolite possesses the necessary constrained access to molecules of larger 
cross-section than normal paraffins, a simple determination of the 
"Constraint Index" as herein defined may be made by passing continuously a 
mixture of an equal weight of normal hexane and 3-methylpentane over a 
sample of zeolite at atmospheric pressure according to the following 
procedure. A sample of the zeolite, in the form of pellets or extrudate, 
is crushed to a particle size about that of coarse sand and mounted in a 
glass tube. Prior to testing, the zeolite is treated with a stream of air 
at 540.degree. C. for at least 15 minutes. The zeolite is then flushed 
with helium and the temperature is adjusted between 290.degree. C. and 
510.degree. C. to give an overall conversion of between 10% and 60%. The 
mixture of hydrocarbons is passed at 1 liquid hourly space velocity (i.e., 
1 volume of liquid hydrocarbon per volume of zeolite per hour) over the 
zeolite with a helium dilution to give a helium to (total) hydrocarbon 
mole ratio of 4:1. After 20 minutes on stream, a sample of the effluent is 
taken and analyzed, most conveniently by gas chromatography, to determine 
the fraction remaining unchanged for each of the two hydrocarbons. 
The "Constraint Index" is calculated as follows: 
##EQU1## 
The Constraint Index approximates the ratio of the cracking rate constants 
for the two hydrocarbons. Zeolites suitable for the present invention are 
those having a Constraint Index of 1 to 12. Constraint Index (CI) values 
for some typical materials are: 
______________________________________ 
Zeolite C.I. 
______________________________________ 
ZSM-5 8.3 
ZSM-11 8.7 
ZSM-12 2 
ZSM-23 9.1 
ZSM-35 4.5 
ZSM-38 2 
ZSM-48 3.4 
TMA Offretite 3.7 
Clinoptilolite 3.4 
H-Zeolon (mordenite) 
0.4 
REY 0.4 
Amorphous Silica-Alumina 
0.6 
Erionite 38 
______________________________________ 
The above-described Constraint Index is an important and even critical 
definition of those zeolites which are useful in the instant invention. 
The very nature of this parameter and the recited technique by which it is 
determined, however, admit of the possibility that a given zeolite can be 
tested under somewhat different conditions and thereby exhibit different 
Constraint Indices. Constraint Index seems to vary somewhat with severity 
of operation (conversion) and the presence or absence of binders. 
Likewise, other variables such as crystal size of the zeolite, the 
presence of occluded contaminants, etc., may affect the constraint index. 
Therefore, it will be appreciated that it may be possible to so select 
test conditions as to establish more than one value in the range of 1 to 
12 for the Constraint Index of a particular zeolite. Such a zeolite 
exhibits the constrained access as herein defined and is to be regarded as 
having a Constraint Index in the range of 1 to 12. Also contemplated 
herein as having a Constraint Index in the range of 1 to 12 and therefore 
within the scope of the defined class of highly siliceous zeolites are 
those zeolites which, when tested under two or more sets of conditions 
within the above-specified ranges of temperature and conversion, produce a 
value of the Constraint Index slightly less than 1, e.g. 0.9, or somewhat 
greater than 12, e.g. 14 or 15, with at least one other value within the 
range of 1 to 12. Thus, it should be understood that the Constraint Index 
value as used herein is an inclusive rather than a exclusive value. That 
is, a crystalline zeolite when identified by any combination of conditions 
within the testing definition set forth herein as having a Constraint 
Index in the range of 1 to 12 is intended to be included in the instant 
zeolite definition whether or not the same identical zeolite, when tested 
under other of the defined conditions, may give a Constraint Index value 
outside of the range of 1 to 12. 
The particular class of zeolites defined herein is exemplified by ZSM-5, 
ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38, ZSM-48 and other similar 
materials. 
ZSM-5 is described in greater detail in U.S. Pat. No. 3,702,886 and U.S. 
Reissue Pat. No. Re. 29,948. The entire descriptions contained within 
those patents, particularly the X-ray diffraction pattern of therein 
disclosed ZSM-5, are incorporated herein by reference. 
ZSM-11 is described in U.S. Pat. No. 3,709,979. That description, and in 
particular the X-ray diffraction pattern of said ZSM-11, is incorporated 
herein by reference. 
ZSM-12 is described in U.S. Pat. No. 3,832,449. That description, and in 
particular the X-ray diffraction pattern disclosed therein, is 
incorporated herein by reference. 
ZSM-23 is described in U.S. Pat. No. 4,076,842. The entire content thereof, 
particularly the specification of the X-ray diffraction pattern of the 
disclosed zeolite, is incorporated herein by reference. ZSM-35 is 
described in U.S. Pat. No. 4,016,245. The description of that zeolite, and 
particularly the X-ray diffraction pattern thereof, is incorporated herein 
by reference. 
ZSM-38 is more particularly described in U.S. Pat. No. 4,046,859. The 
description of that zeolite, and particularly the specified X-ray 
diffraction pattern thereof, is incorporated herein by reference. 
ZSM-48 is more particularly described in allowed U.S. patent application 
Ser. No. 343,131, filed Jan. 27, 1982, the content of which is 
incorporated herein by reference. 
It is to be understood that by incorporating by reference the foregoing 
patents to describe examples of specific members of the zeolite class with 
greater particularity, it is intended that identification of the therein 
disclosed crystalline zeolites be resolved on the basis of their 
respective X-ray diffraction patterns. As discussed above, the present 
invention contemplates utilization of such catalysts wherein the mole 
ratio of silica to alumina is essentially unbounded. The incorporation of 
the identified patents should therefore not be construed as limiting the 
disclosed crystalline zeolites to those having the specific silica-alumina 
mole ratios discussed therein, it now being known that such zeolites may 
be substantially aluminum-free and yet, having the same crystal structure 
as the disclosed materials, may be useful or even preferred in some 
applications. It is the crystal structure, as identified by the X-ray 
diffraction "fingerprint", which establishes the identity of the specific 
siliceous crystalline zeolite material. 
The specific zeolites described, when prepared in the presence of organic 
cations, are substantially catalytically inactive, possibly because the 
intra-crystalline free space is occupied by organic cations from the 
forming solution. They may be activated by heating in an inert atmosphere 
at 540.degree. C. for one hour, for example, followed by base exchange 
with ammonium salts followed by calcination at 540.degree. C. in air. The 
presence of organic cations in the forming solution may not be absolutely 
essential to the formation of this type zeolite; however, the presence of 
these cations does appear to favor the formation of this special class of 
zeolite. More generally, it is desirable to activate this type catalyst by 
base exchange with ammonium salts followed by calcination in air at about 
540.degree. C. for from about 15 minutes to about 24 hours. 
Natural zeolites may sometimes be converted to zeolite structures of the 
class herein identified by various activation procedures and other 
treatments such as base exchange, alumina extraction and calcination, 
alone or in combinations. Natural minerals which may be so treated include 
ferrierite, brewsterite, stilbite, dachiardite, epistilbite, heulandite, 
and clinoptilolite. 
The preferred siliceous crystalline zeolites for utilization herein include 
ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38 and ZSM-48, with ZSM-5 being 
particularly preferred. 
In a preferred aspect of this invention, the zeolites hereof are selected 
as those providing among other things a crystal framework density, in the 
dry hydrogen form, of not less than about 1.6 grams per cubic centimeter. 
It has been found that zeolites which satisfy all three of the discussed 
criteria are most desired. 
Therefore, the preferred zeolites useful with respect to this invention are 
those having a Constraint Index as defined above of about 1 to about 12, a 
silica to alumina mole ratio of at least about 12 and a dried crystal 
density of not less than about 1.6 grams per cubic centimeter. The dry 
density for known structures may be calculated from the number of silicon 
plus aluminum atoms per 1000 cubic Angstroms, as given, e.g., on Page 19 
of the article ZEOLITE STRUCTURE by W. M. Meier. This paper, the entire 
contents of which are incorporated herein by reference, is included in 
PROCEEDINGS OF THE CONFERENCE ON MOLECULAR SIEVES, (London, April 1967) 
published by the Society of Chemical Industry, London, 1968. 
When the crystal structure is unknown, the crystal framework density may be 
determined by classical pycnometer techniques. For example, it may be 
determined by immersing the dry hydrogen form of the zeolite in an organic 
solvent which is not sorbed by the crystal. Or, the crystal density may be 
determined by mercury porosimetry, since memory will fill the interstices 
between crystals but will not penetrate the intracrystalline free space. 
It is possible that the unusual sustained activity and stability of this 
special class of zeolites is associated with its high crystal anionic 
framework density of not less than about 1.6 grams per cubic centimeter. 
This high density must necessarily be associated with a relatively small 
amount of free space within the crystal, which might be expected to result 
in more stable structures. This free space, however, is important as the 
locus of catalytic activity. 
Crystal framework densities of some typical zeolites, including some which 
are not within the purview of this invention, are: T1 - Void? Framework? 
- Volume? Density? -Ferrierite 0.28 cc/cc 1.76 g/cc -Mordenite .28 1.7 
-Z5M-5, -11 .29 1.79 -ZSM-12 -- 1.8 -ZSM-23 -- 2.0 -Dachiardite .32 
1.72 -L .32 1.61 -Clinoptilolite .34 1.71 -Laumontite .34 1.77 -ZSM-4 
(Omega) .38 1.65 -Heulandite .39 1.69 -P .41 1.57 -Offretite .40 1.55 
-Levynite .40 1.54 -Erionite .35 1.51 -Gmelinite .44 1.46 -Chabazite 
.47 1.45 -A .5 1.3 -Y .48 1.27 - 
The size of the zeolite crystals employed in the alkylation catalyst 
composites of this invention can also affect the selective catalytic 
properties of such a catalyst. For highest selectivity to para-isomer 
alkylation, it is preferred that the size of the zeolite crystals utilized 
range from about 1 to 10 microns, more preferably from about 2 to 4 
microns along the major dimension (crystal length) and from about 0.2 to 4 
microns, more preferably from about 0.5 to 2 microns along the minor 
dimension (crystal thickness). 
When synthesized in the alkali metal form, the zeolite used to form the 
base catalyst composite can be conveniently converted in a conventional 
manner to the hydrogen form, generally by intermediate formation of the 
ammonium form as a result of ammonium ion exchange and calcination of the 
ammonium form to yield the hydrogen form of the zeolite. In addition to 
the hydrogen form, other forms of the zeolite can be employed in the base 
catalyst composition so long as the original alkali metal has been reduced 
to less than about 50% by weight of the original alkali metal contained in 
the zeolite as-synthesized, usually 0.5% by weight or less. Thus, the 
original alkali metal of the zeolite may be replaced by ion exchange with 
other suitable metal cations of Groups I through VIII of the Periodic 
Table, including, by way of example, nickel, copper, zinc, palladium, 
calcium or rare earth metals. 
In preparing the zeolite-containing base catalyst composites of the present 
invention, the above-described siliceous crystalline zeolite material is 
combined with a matrix comprising another material resistant to the 
temperature and other conditions employed in the process for preparing the 
modified catalyst composites of the present invention and/or in the 
subsequent aromatics alkylation process embodiments in which such catalyst 
composites are employed. Such matrix material is useful as a binder and 
imparts greater resistance to the catalyst for the severe temperature, 
pressure and reactant feed stream velocity conditions encountered in such 
processes. 
Useful matrix materials include both synthetic and naturally occurring 
substances, as well as inorganic materials such as clay, silica and/or 
metal oxides. The latter may be either naturally occurring or in the form 
of gelatinous precipitates or gels including mixtures of silica and metal 
oxides. Naturally occurring clays which can be composited with the zeolite 
include those of the montmorillonite and kaolin families, which families 
include the sub-bentonites 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. 
In addition to the foregoing materials, the binder for the siliceous 
crystalline zeolite material employed herein can comprise a porous matrix 
material, such as alumina, silica-alumina, silica-magnesia, 
silica-zirconia, silica-thoria, silica-beryllia, and silica-titania, as 
well as ternary compositions, such as silica-alumina-thoria, 
silica-alumina-zirconia, silica-alumina-magnesia and 
silica-magnesia-zirconia. The matrix may be in the form of a cogel. The 
relative proportions of zeolite component and inorganic oxide gel matrix, 
on an anhydrous basis, may vary widely with the zeolite content ranging 
from between about 1 to about 99 percent by weight and more usually in the 
range of about 25 to about 80 percent by weight of the dry base composite. 
In prior art processes for modifying base catalyst composites of the type 
hereinbefore described, such base catalyst composites of this type are 
frequently subjected at this point in catalyst preparation to a 
pre-steaming procedure as one step in the process of preparing 
para-selective aromatics alkylation catalysts. Such pre-steaming treatment 
serves to enhance the para-selectivity characteristics of the alkylation 
catalyst eventually prepared. It has been discovered that by employing the 
particular base catalyst composite treatment procedure hereinafter 
described, such a pre-steaming step can be eliminated and yet the 
para-selectivity of the resulting alkylation catalyst will be as good as 
or better than that of a steam selectivated Mg-P impregnated catalyst of 
the prior art. 
Thus, as a second step in the catalyst preparation process of the present 
invention, the base catalyst composites prepared as hereinbefore described 
can be contacted with an aqueous solution of the particular selected 
catalyst modifying agent magnesium nitrate. Such contact of base catalyst 
composites with magnesium nitrate solution generally occurs under 
treatment conditions which are, and for a time period which is, sufficient 
to incorporate from about 25% to 50%, more preferably from about 30% to 
43%, by weight of magnesium nitrate onto the base catalyst composite on an 
anhydrous basis. 
The aqueous solution of magnesium nitrate used in this contacting step can 
be prepared by simply dissolving an appropriate form of magnesium nitrate, 
e.g., Mg(NO.sub.3).sub.2.2H.sub.2 O or Mg(NO.sub.3).sub.2.6H.sub.2 O, with 
water to form the treating solution for the base catalyst composites. If 
desired, inert cosolvents such as lower alkanols can be employed in 
forming this magnesium nitrate solution. Magnesium nitrate concentrations 
of from about 40% to 65%, more preferably from about 60% to 65%, by weight 
of solution can advantageously be employed in forming the magnesium 
nitrate composite treating solution. 
Contact between base catalyst composites and magnesium nitrate solution can 
be effected by any suitable means conventionally used to treat solid 
particulate material with a treating agent in liquid form. Such techniques 
can, for example, involve soaking the base catalyst composites in the 
magnesium nitrate solution in a suitable vessel or may involve continuous 
or intermittent contact of the magnesium nitrate solution with a bed of 
catalyst composite particles. The ebullated bed arrangement of Bowes; U.S. 
Pat. No. 4,292,205; issued Sept. 29, 1981, incorporated herein by 
reference, represents another useful means for effecting catalyst contact 
with the magnesium nitrate treating solution. 
No matter what particular contact arrangement may be employed, the handling 
of the magnesium nitrate solution in such procedures is generally much 
easier than the handling of the impregnating solutions in corresponding 
prior art procedures which utilize comparatively much more viscous 
solutions of magnesium acetate. The viscous behavior of concentrated 
magnesium acetate solutions can make catalyst impregnation difficult in 
such prior art processes since channeling and catalyst flotation may 
become problems in larger vessels used for impregnation. Catalyst 
treatment using magnesium nitrate solutions, on the other hand, can be 
accomplished with fewer processing and equipment difficulties in 
comparison with magnesium acetate impregnation. It is furthermore apparent 
that since the magnesium nitrate treated catalyst composites are not to be 
phosphorus-modified, the composites of the present invention are not 
therefore contacted with solutions of phosphorus compounds either prior to 
or subsequent to their treatment with the magnesium nitrate solution. 
The efficiency of commercial scale catalyst composite impregnation is also 
significantly improved with magnesium nitrate impregnation in comparison 
with impregnation using aqueous magnesium acetate solution. Using 
magnesium nitrate solutions, it is in fact possible to incorporate the 
requisite amount of magnesium onto the catalyst composite in a single 
impregnation stage without intermediate drying or calcination, provided 
the impregnated catalyst material is dried by free convection methods. 
Even when forced convection gas is used to dry the impregnated composites 
(thereby blowing some of the impregnating solution off the catalyst 
material), it is possible to reach optimum magnesium content using a 
magnesium nitrate impregnant in as few as two impregnation stages. 
As noted, contact between magnesium nitrate treating solution and the base 
catalyst composites occurs for a time period which is sufficient to effect 
incorporation of the requisite amount of magnesium nitrate onto the base 
catalyst composites. Contact times of at least about 0.5 hour, more 
preferably from about 1 to 2 hours, may advantageously be utilized. 
Contacting conditions will generally also include a contact temperature 
from about 10.degree. C. to 65.degree. C., more preferably from about 
20.degree. C. to 55.degree. C. The resulting impregnated composites will 
generally contain from about 25% to 50% by weight, more preferably from 
about 30% to 45% by weight, of magnesium nitrate on an anhydrous basis. 
After contact of the catalyst composites with magnesium nitrate solution is 
completed to the extent desired, the treated catalyst composites can 
thereafter be dried and calcined to form the finished catalyst 
compositions suitable for use in promoting para-selective alkylation 
reactions. Calcination will generally occur in a nitrogen and/or 
oxygen-containing atmosphere, e.g. air, which may also contain diluents 
such as helium and the like. Calcination can be carried out at a 
temperature of from about 200.degree. C. to 565.degree. C., more 
preferably from about 510.degree. C. to 540.degree. C., and for a time 
sufficient to provide a modified catalyst composition containing from 
about 4% to 8%, more preferably from about 6% to 7%, by weight of 
magnesium on the finished catalyst composition. At least some of the 
magnesium present in the calcined catalyst composition is thus present in 
the form of magnesium oxide. Calcination under such conditions can thus 
advantageously be carried out for a period of from about 1 to 6 hours, 
more preferably from about 2 to 6 hours. 
The magnesium nitrate treated zeolite catalysts of the present invention 
can be advantageously used to promote conversion of mono-alkyl aromatic 
compounds to provide dialkyl substituted benzene product mixtures which 
are highly enriched in the para-dialkyl substituted benzene isomer. 
Conversion reactions of this type thus involve an aromatics alkylation 
reaction. Alkylation of aromatic compounds in the presence of the 
above-described catalysts can be effected by contact of the aromatic with 
an alkylating agent under alkylatio conditions. A particularly preferred 
embodiment involves the alkylation of toluene wherein the alkylating 
agents employed comprise methanol or other well known methylating agents 
or ethylene. The reaction is carried out at a temperature of between about 
250.degree. C. and about 750.degree. C., preferably between about 
300.degree. C. and 650.degree. C. At higher temperatures, the zeolites of 
high silica/alumina ratio are preferred. For example, ZSM-5 having a 
SiO.sub.2 /Al.sub.2 O.sub.3 ratio of 30 and upwards is exceptionally 
stable at high temperatures. The reaction generally takes place at 
atmospheric pressure, but pressures within the approximate range of 
10.sup.5 n/m.sup.2 to 10.sup. 7 N/m.sup.2 (1-100 atmospheres) may be 
employed. 
Some non-limiting examples of suitable alkylating agents would include 
olefins such as, for example, ethylene, propylene, butene, decene and 
dodecene, as well as formaldehyde, alkyl halides and alcohols, the alkyl 
portion thereof having from 1 to 16 carbon atoms. Numerous other aliphatic 
compounds having at least one reactive alkyl radical may be utilized as 
alkylating agents. 
Aromatic compounds which may be selectively alkylated as described herein 
would include any alkylatable mono-alkyl aromatic hydrocarbon such as, for 
example, ethylbenzene, toluene, propylbenzene, ispropylbenzene, or 
substantially any mono-substituted benzenes which are alkylatable in the 
4-position of the aromatic ring. 
The molar ratio of alkylating agent to aromatic compound is generally 
between about 0.05 and about 2. For instance, when methanol is employed as 
the methylating agent and toluene is the aromatic, a suitable molar ratio 
of methanol to toluene has been found to be approximately 0.1 to 1.0 mole 
of methanol per mole of toluene. When ethylene is employed a the 
alkylating agent and toluene is the aromatic, a suitable molar ratio of 
ethylene to toluene is approximately 0.05 to 2.5 moles of ethylene per 
mole of toluene. 
Alkylation is suitably accomplished utilizing a feed weight hourly space 
velocity (WHSV) of between about 1 and about 100, and preferably between 
about 1 and about 50. The reaction product, consisting predominantly of 
the 1,4-dialkyl isomer, e.g. 1,4-dimethylbenzene, 1-ethyl-4-methylbenzene, 
etc., or a mixture of the 1,4- and 1,3-isomer, may be separted by any 
suitable means. Such means may include, for example, passing the reaction 
product stream through a water condenser and subsequently passing the 
organic phase through a column in which chromatographic separation of the 
aromatic isomers is accomplished. Alkylation using the magnesium 
nitrate-treated catalysts of the present invention can provide product 
mixtures containing at least 80% or even 90% or more by weight of the 
para-dialkylbenzene isomer. 
The aromatics alkylation process described herein may be carried out as 
batch type, semi-continuous or continuous operations utilizing a fluid or 
moving bed catalyst system. The catalyst after use in a moving bed reactor 
can be conducted to a regeneration zone wherein coke is burned from the 
catalyst in an oxygen-containing atmosphere, e.g. air, at an elevated 
temperature, after which the regenerated catalyst can be recycled to the 
alkylation zone for further contact with the charge stock. In a fixed bed 
reactor, regeneration can be carried out in a conventional manner where an 
inert gas containing a small aount of oxygen (0.5-2%) is used to burn the 
coke in a controlled manner so as to limit the temperature to a maximum of 
around 500.degree. C.-550.degree. C. 
Siliceous zeolite crystal-containing composites treated with magnesium 
nitrate according to this invention show remarkably better catalytic 
properties for the alkylation of monoalkylbenzene than do corresponding 
composites impregnated with magnesium acetate to the same magnesium 
content. It is recognized that the above referenced U.S. Pat. No. 
4,117,024 describes and claims siliceous crystals impregnated with one or 
more of phosphorus, boron, antimony or magnesium and that this patent 
describes a host of magnesium introducing impregnants including inter alia 
magnesium acetate and magnesium nitrate (see Column 10, line 15 et seq.). 
It is also recognized that U.S. Pat. No. 4,117,024 describes and prefers 
the use of relatively large crystals, about 1 to 5 microns, (see Column 
12, lines 51 et seq.) of siliceous zeolite materials. However U.S. Pat. 
No. 4,117,024 does not recognize that crystal-containing composites 
impregnated with magnesium nitrate are not equivalent to such composite 
impregnated with other magnesium salts, notably magnesium acetate, for the 
alkylation, e.g., ethylation, of mono substituted, particularly alkylated, 
most particularly methyl, benzenes to produce the desired product 
distribution described above in an optimal fashion. The particular 
magnesium-containing composites of the present invention which have been 
prepared using a magnesium nitrate impregnant in fact represent catalysts 
which provide improved conversion of monoalkylaromatics ot 
dialkylaromatics, with improved selectivity of such conversion to 
production of para-dialkyl aromatic isomers and with reduced time 
off-stream for catalyst regeneration and re-selectivation. 
Without being bound to any particular theory of invention operability, it 
is speculated that the catalyst performance benefits achieved with the 
magnesium nitrate impregnated catalyst composite result from the enhanced 
tendency of magnesium nitrate solutions to deliver magnesium to the 
siliceous zeolite crystal portion of the catalyst composite versus the 
binder portion of the composite. It is perhaps this enhanced incorporation 
of magnesium from MgNO.sub.3 into the siliceous zeolite crystalline 
material which permits elimination of the binder passivating phosphorus 
treatment step which is necessary to produce composites of desirably high 
para-selectivity when a magnesium acetate impregnant is employed.

The following examples will serve to illustrate certain specific 
embodiments of the hereindisclosed invention. These examples should not, 
however, be construed as limiting the scope of the invention, as there are 
many variations which may be made thereon without departing from the 
spirit of the disclosed invention, as those of skill in the art will 
recognize. 
EXAMPLE I 
Part A--Converting Extrudate to Ammonium Form 
Untreated base catalyst composites utilized are in the form of 1/6" 
extrudate containing 65% by weight ZSM-5 and 35% by weight alumina binder. 
ZSM-5 crystal size in such composites is approximately 1 micron in length, 
0.5 micron in thickness. Six pounds (2728 g; 4200 cc) of this dried 
extrudate are charged to an ion exchange/calcination vessel. Extrudate 
therein is precalcined in N.sub.2 at 540.degree. C. for 3 hours at a flow 
rate of 1.25 SCFM. 
After cooling, the extrudate is ion exchanged with 42 pounds of 1 N 
ammonium nitrate solution at room temperature for one hour. After 
draining, the procedure is repeated and followed by 5 volumetric washes 
with deionized water. (Each is one complete fill followed by draining.) 
The extrudate is then dried in warm flowing N.sub.2 and sampled. Sodium 
content is less than 0.01 wt. %. The zeolitic portion of the extrudate is 
now in the ammonium form with the extrudate having the following 
composition: 
65% NH.sub.4 --ZSM-5 
35% Alumina 
Part B--First Magnesium Impregnation 
Twelve kilograms of 60% weight Mg(NO.sub.3).sub.2.6H.sub.2 O are prepared. 
This solution is introduced to the ammonium form extrudate still in place 
in the ion exchange/calcination vessel. The solution is pumped upflow in a 
recycle mode for 5 minutes, then allowed to stand for one hour, all at 
room temperature. Before draining, the solution is again circulated for 5 
minutes at 650 cc/min. Solution is then drained and the extrudate dried in 
warm N.sub.2 at a flow of 0.55 SCFM. 
After all points in the bed registered greater than 250.degree. F. 
(120.degree. C.), the extrudate is considered completely dry. Gas flow 
rate is increased to 1.25 SCFM and temperatures increased to effect 
calcination. When bed temperatures are approximately 425.degree. C. 
(800.degree. F.), gas composition is changed to air, and the temperature 
increased to approximately 540.degree. C. (1000.degree. F.) and held for 2 
hours. The bed is then cooled in N.sub.2 and sampled. 
The sample is found to have 3.8 wt. % Mg and an alpha activity of 51. 
Part C--Second Magnesium Impregnation 
7.9 Kg of magnesium nitrate solution recovered from the first impregnation 
is supplemented with 2.1 Kg of fresh 60% Mg(NO.sub.3).sub.2.6H.sub.2 O to 
effect a second impregnation of the extrudate still in the vessel. The 
procedure is exactly as described for the first impregnation, including 
draining, drying and calcination. After cooling, the contents of the 
vessel are discharged. The finished catalyst is characterized as follows: 
Weight: 2347 g 
Wt. % Mg: 6.6 
% Ash (1000.degree. C.): 96.78 
Alpha Activity: 28 
EXAMPLE II 
A large scale batch of ammonium form extrudate is prepared as described in 
Part A of Example I. A sample of this extrudate (800 cc) is steamed in 
laboratory steamers (400 cc each) in 100% steam, at one atmosphere and 
540.degree. C. (1000.degree. F.) for 5 hours. 
A sample of the steamed extrudate (100 cc) is impregnated in a beaker with 
200 cc of a 66 wt. % solution of Mg(NO.sub.3).sub.2.6H.sub.2 O for one 
hour at room temperature, with occasional stirring. The extrudate is 
drained on a screen, placed in a porcelain evaporating dish which is 
placed in a laboratory drier kept at 120.degree. C. (250.degree. F.), and 
allowed to dry over a weekend. 
The dried impregnated extrudate is then placed in a one pint muffle pot (a 
device to hold catalyst and allow positive gas flow from outside a muffle 
furnace) and is heated in 300 cc/min of N.sub.2 to a temperature of about 
425.degree. (800.degree. F.). At this point N.sub.2 is replaced by air and 
the temperature of the impregnated extrudate is increased to 540.degree. 
C. (1000.degree. F.) and held for two hours. The sample is cooled down in 
N.sub.2. 
Such a catalyst sample has a magnesium content of 7.0% by weight. 
EXAMPLE III 
The procedure of Example II is repeated with a separate sample of ammonium 
form ZSM-5 extrudate. In this procedure, however, the concentration of the 
impregnating solution is 60% by weight Mg(NO.sub.3).sub.2.6H.sub.2 O. 
Such a catalyst sample has a magnesium content of 6.4% by weight. 
EXAMPLE IV 
A 50 cc sample of the ammonium form ZSM-5 extrudate of Example I is 
calcined in N.sub.2 for 3 hours at 540.degree. C. (1000.degree. F.). The 
cooled sample is then impregnated at 55.degree. C. (130.degree. F.) with 
100 cc of a 60% Mg(OAc).sub.2.4H.sub.2 O solution for 2 hours. The sample 
is drained, dried and calcined as described in Example II. 
Such a catalyst sample has a magnesium content of 7.3% by weight. 
EXAMPLE V 
A 100 cc sample of the ammonium form ZSM-5 extrudate of Example I is 
calcined in N.sub.2 for 3 hours at 540.degree. C. (1000.degree. F.). The 
sample is cooled and impregnated with 60% Mg(NO.sub.3).sub.2.6H.sub.2 O 
(200 cc) for one hour at room temperature. The sample is then drained, 
dried and calcined as described in Example II. 
Such a catalyst sample has a magnesium content of 6.9% by weight. 
EXAMPLE VI 
A 100 cc sample of another batch of ammonium form ZSM-5 extrudate prepared 
in a manner substantially similar to that of Example I is impregnated with 
Mg using 200 cc of a 60% solution of Mg(NO.sub.3).sub.2.6H.sub.2 O for one 
hour at 55.degree. C. (130.degree. F.). The sample is then drained, dried 
and calcined as described in Example II. 
Such a catalyst sample has a magnesium content of 6.8% by weight. 
EXAMPLE VII 
A 50 cc sample of the same batch of ammonium form ZSM-5 extrudate of 
Example VI is impregnated using 100 cc of 55% Mg(NO.sub.3).sub.2.6H.sub.2 
O solution for one hour at room temperature (approximately 75.degree. F.). 
The sample is then drained, dried and calcined as described in Example II. 
Such a catalyst sample has a magnesium content of 6.2% by weight. 
EXAMPLE VIII 
The procedure of Example VII is repeated with a separate sample of the same 
ammonium form ZSM-5 extrudate. In this procedure, however, the 
concentration of the impregnating solution is 50% by weight of 
Mg(NO.sub.3).sub.2.6H.sub.2 O. 
Such a catalyst sample has a magnesium content of 5.4% by weight. 
EXAMPLE IX 
A 50 cc sample of the ammonium form ZSM-5 extrudate from the ion 
exchange/calcination vessel of Example I is impregnated with 100 cc of 60% 
Mg(NO.sub.3).sub.2.6H.sub.2 O for one hour at room temperature 
(approximately 75.degree. F.). 
Such a catalyst sample has a magnesium content of 7.3% by weight. 
EXAMPLE X 
Approximately 4,800 lbs. of untreated ZSM-5 base catalyst composites of the 
type described in Example I, Part A, are charged to an ion 
exchange/calcination vessel. The bed of extrudate in the vessel is heated 
in N.sub.2 to 1000.degree. F. and held for 3 hours (640 SCFM of N.sub.2). 
After cooling in N.sub.2, the bed is ion-exchanged with a solution made up 
from 600 lbs. of ammonium nitrate and 2,530 gallons of deionized water for 
3 hours at ambient temperature with a circulation of 100 gallons per 
minute. After draining and washing with 2,500 gallons of deionized water, 
the procedure is repeated. A sample from the bed, after drying analyzes at 
0.01 wt. % Na. 
The bed is dried, unloaded and split in half. One half, i.e. 2,393 lbs., 
are reloaded into the vessel. The bed is impregnated with a 60% weight 
solution of Mg(NO.sub.3).sub.2.6H.sub.2 O made by dissolving 10,500 lbs. 
of Mg(NO.sub.3).sub.2.6H.sub.2 O in 839 gallons of deionized water. After 
the bed is completely wetted, solution is circulated for 15 minutes at 650 
gallons per minute. Solution is allowed to stand for one hour and is then 
recirculated again for 15 minutes. Solution is then drained by pumping 
solution back to the original solution tank. 
The treated extrudate is then dried by flow of air (130 SCFM) at 
450.degree. F. leaving the furnace. After 48 hours, the bed is considered 
completely dry (all temperatures above 325.degree. F.), and flow is 
switched to N.sub.2 and increased to 720 SCFM for calcination. The furnace 
temperature is increased, and at an average bed temperature of 800.degree. 
F., the furnace is held constant for 2 hours. N.sub.2 is then replaced 
with air, and the furnace temperature is increased to give a temperature 
of 1000.degree. F. in the bed. These conditions are held for 2 hours. The 
bed is then cooled in air to 400.degree. F., then in N.sub.2 to less than 
125.degree. F. and sampled. 
At this point a second batch of impregnated catalyst is made. The first 
batch of 2,400 lbs. is discharged from the ion exchange/calcination 
vessel. The remaining dried extrudate is loaded into the vessel, and the 
foregoing impregnation procedure is repeated exactly. The two batches are 
then combined in the vessel for one final impregnation. 
The final impregnation step, draining, drying and calcination are exactly 
as hereinbefore described except that the vessel contains about 4,800 lbs. 
of extrudate. Magnesium nitrate solution is reused from the solution task. 
Intermediate samples and final products have the following 
characteristics. 
______________________________________ 
Alpha Activity 
Wt. % Mg 
______________________________________ 
First Batch, First Impregnation 
32 3.4 
Second Batch, First Impregnation 
35 -- 
Final Product 27 7.0 
______________________________________ 
EXAMPLE XI 
The catalyst samples from the foregoing examples are tested for their 
ability to promote alkylation of toluene with ethylene. In the procedure 
for conducting such testing, approximately 15 cc of catalyst are charged 
to a 5/8" diameter stainless steel reactor fitted with a central 
thermowell. The reactor is placed in a three zone split furnace and heated 
in flowing N.sub.2 to 800.degree. F. N.sub.2 is then replaced by H.sub.2, 
toluene is introduced, followed by ethylene. The inlet temperature to the 
reactor is adjusted to 810.degree. F. The pressure is controlled at 100 
psig inlet to the reactor, and the flows are adjusted to give an 8.8:1:3 
molar ratio of toluene/ethylene/hydrogen. On a WHSV basis, this is 
29:1:0.2 (i.e. 29 g toluene/g catalyst/hour). 
Two hours after introduction of ethylene (line-out period), collection of 
the liquid product is begun. After one hour, the product is removed, 
weighed and analyzed by gas chromatograph. Gas produced during the hour is 
also measured volumetrically and analyzed by mass spectroscopy. 
Data from these analyses are combined by computer program to give an 
overall material-balanced run result. Especially noted is the proportion 
of para-ethyltoluene in ethyltoluenes, PET/ET, and the ratio of toluene 
converted to theoretical toluene conversion if all ethylene fed reacted 
stoichiometrically with toluene to give ethyltoluene. 
Results for such testing of catalyst samples from Examples I-X are set 
forth in Table I. 
TABLE I 
______________________________________ 
Alkylation of Toluene with Ethylene 
Over Mg ZSM-5 Catalysts 
Toluene 
% Wt. PET/ET Conver- 
Catalyst Sample 
Impregnant Mg % sion % 
______________________________________ 
Example I Mg(NO.sub.3).sub.2.6H.sub.2 O 
6.6 99.2 86 
Example II 
Mg(NO.sub.3).sub.2.6H.sub.2 O 
7.0 95 65 
Example III 
Mg(NO.sub.3).sub.2.6H.sub.2 O 
6.4 93 78 
Example IV 
Mg(OAc).sub.2.4H.sub.2 O 
7.3 83 94 
Example V Mg(NO.sub.3).sub.2.6H.sub.2 O 
6.9 97 88 
Example VI 
Mg(NO.sub.3).sub.2.6H.sub.2 O 
6.8 94 88 
Example VII 
Mg(NO.sub.3).sub.2.6H.sub.2 O 
6.2 84 92 
Example VIII 
Mg(NO.sub.3).sub.2.6H.sub.2 O 
5.4 67 100 
Example IX 
Mg(NO.sub.3).sub.2.6H.sub.2 O 
7.3 97 88 
Example X, 
Mg(NO.sub.3).sub.2.6H.sub.2 O 
3.4 52.6 98 
First Batch 
Example X, 
Mg(NO.sub.3).sub.2.6H.sub.2 O 
-- 51.2 99 
Second Batch 
Example X, 
Mg(NO.sub.3).sub.2.6H.sub.2 O 
7.0 97.6 89 
Final Product 
______________________________________