Molecular sieve abstract
Described are catalyst compositions comprising a HAMS-1B crystalline
borosilicate molecular sieve, the majority of the crystallites of
which are between about 1 micron and about 15 micron in largest
diameter, incorporated into an inorganic matrix, which have been
impregnated with a small amount of a magnesium compound, said impregnated
compositions having improved para-selectively for toluene methylation
to xylene. Such impregnated compositions, when used for the methylation
of toluene using methanol or dimethylether, yield a xylene product
containing a very high proportion of the para isomer compared to
corresponding unimpregnated or magnesium compound-impregnated borosilicate-based
compositions containing standard size (0.2.mu. to 0.5.mu.) borosilicate
molecular sieve crystallites.
Molecular sieve claims
What is claimed is:
1. A process for making paraxylene by methylating toluene in the
presence of a catalyst composition comprising a HAMS-1B crystalline
borosilicate molecular sieve, the majority of the crystallites of
which are between about 1 micron and about 15 microns in largest
dimesion, incorporated into an inorganic matrix, said composition
impregnated by a magnesium compound and subsequently heated to substantially
convert said compound to the oxide form.
2. A process for making paraxylene by methlating toluene in the
presence of the catalyst composition of claim 1 said composition
containing between about 4 and about 25% by weight magnesium.
3. A process for making paraxylene by methylating toluene in the
presence of the catalyst composition of claim 2 wherein said HAMS-1B
molecular sieve comprises from about 20 to about 80% incorporated
into an alumina, silica, or silica-alumina matrix.
4. A process for making paraxylene by methylating toluene in the
presence of the catalyst composition of claim 1 wherein the majority
of the crystals of HAMS-1B molecular sieve are between about 2 microns
and 10 microns.
5. A process for making paraxylene by methylating toluene in the
presence of the catalyst composition of claim 4 wherein said composition
contains between about 4 percent and about 25 percent by weight
magnesium.
6. A process for making paraxylene by methylating toluene in the
presence of the catalyst composition of claim 5 wherein said HAMS-1B
molecular sieve comprises about 20 to 80% incorporated into an alumina,
silica, or silica-alymina matrix.
7. A process for making paraxylene by methylating toluene with
methanol in the presence of the catalyst composition of claim 3.
8. A process for making paraxylene by methylating toluene with
methanol in the presence of the catalyst composition of claim 6.
Molecular sieve description
BACKGROUND OF THE INVENTION
This invention relates to improved AMS-1B crystalline molecular
sieve-based catalyst compositions, and particularly, to the use
of such compositions having improved para-selectivity for toluene
methylation. More particularly, it relates to improved compositions
comprising larger crystallite AMS-1B molecular sieves incorporated
into an inorganic matrix which have been impregnated by a magnesium
compound and to processes for using these improved compositions
to selectively para-methylate toluene to xylene.
In U.S. Pat. Nos. 4504690 4128592 and 4086287 is taught
modifying a ZSM-5 aluminosilicate zeolite catalyst with P, Mg, or
P/Mg oxides to obtain high proportions of the 14-dialkyl isomer.
Phosphorus or Mg modified ZSM-5 zeolite catalysts for the disproportionation
of toluene are shown in J. Appl. Polym. Sci. 36 209 (1981). Disproportionation
of toluene to produce benzene over P, Mg modified crystalline aluminosilicate
zeolite catalysts is described in U.S. Pat. No. 4137195. Alkylation
or disproportionation of certain monosubstituted benzene compounds
to achieve nearly 100% selectivty to para-disubstituted derivatives
over magnesium compound-modified ZSM-5 aluminosilicate zeolite catalysts
is reported in J. Am. Chem. Sec. 101 6783 (1979). In the same article
an increase in para-selectivity is shown by larger crystal size
ZSM-5 zeolite catalysts during toluene methylation.
Use of Mg alone or in combination with P to modify a ZSM-5 aluminosilicate
zeolite catalyst is described in U.S. Pat. No. 4049573 and the
modified catalyst is used for converting alcohols and ethers to
hydrocarbons. Again, Mg is used to modify ZSM-5 zeolite catalysts
in U.S. Pat. No. 4002698 which can be used for selective production
of p-xylene from charge stocks of toluene and a C.sub.3 -C.sub.10
olefin; P modified catalysts for the methylation of toluene are
also described.
Catalyst compositions, generally useful for hydrocarbon conversion,
based upon AMS-1B crystalline borosilicate molecular sieve have
been described in U.S. Pat. Nos. 4268420 4269813 4285919
and Published European application No. 68796.
As described in the references in the paragraph above, catalyst
compositions typically are formed by incorporating an AMS-1B crystalline
borosilicate molecular sieve material into a matrix such as alumina,
silica, or silica-alumina to produce a catalyst formulation. In
one method of making AMS-1B crystalline borosilicate, sieve is formed
by crystallizing sources for silicon oxide and boron oxide with
sodium hydroxide and an organic compound. After crystallization,
the resulting sodium form is ion exchanged with an ammonium compound
and calcined to yield the hydrogen form of AMS-1B . In another and
more preferred method, AMS-1B crystalline borosilicate is crystallized
in the hydrogen form from a mixture containing a diamine in place
of a metal hydroxide. AMS-1B borosilicates in hydrogen form are
designated HAMS-1B . Typically, the hydrogen form sieve is gelled
with an alumina sol, dried, and calcined to yield a catalyst composition.
SUMMARY OF THE INVENTION
Described herein are improved catalyst compositions comprising
a HAMS-1B crystalline borosilicate molecular sieve, the majority
of the crystallites of which are between about 1 micron and about
15 microns in largest dimension, incorporated into a matrix, which
compositions have been impregnated with a small amount of a suitable
magnesium compound and heated. Said impregnated compositions show
an improved para-selectivity for toluene methylation to xylene when
contacted under conversion conditions with methanol or methyl ether
as compared with either unimpregnated borosilicate based compositions
or magnesium impregnated compositions employing the standard size
(0.2.mu. to 0.5.mu.) borosilicate sieve.
DETAILED DESCRIPTION OF THE INVENTION
The catalyst compositions used in this invention are based on AMS-1B
crystalline borosilicate molecular sieve, which is described in
U.S. Pat. Nos. 4268420; 4269813; and 4285919 and Published
European Patent application No. 68796 all incorporated herein
by reference. AMS-1B crystalline borosilicate generally can be characterized
by the X-ray pattern listed in Table A and by the composition formula:
Wherein R is an organic compound and M is at least one cation having
the oxidation state n, such as an alkali or an alkaline earth metal
cation or hydrogen. By regulation of the quantity of boron (represented
as B.sub.2 O.sub.3) in the reaction mixture, it is possible to vary
the SiO.sub.2 /B.sub.2 O.sub.3 molar ratio in the final product.
More specifically, the material useful in the present invention
is prepared by mixing a base, a boron oxide source, and an organic
template compound in water (preferably distilled or deionized).
The order of addition usually is not critical although a typical
procedure is to dissolve base and boric acid in water and then add
the template compound. Generally, the silicon oxide compound is
added with intensive mixing such as that performed in a Waring Blendor
and the resulting slurry is transferred to a closed crystallization
vessel for a suitable time. After crystallization, the resulting
crystalline product can be filtered, washed with water, dried, and
calcined.
During preparation, acidic conditions should be avoided. When alkali
metal hydroxides are used, the values of the ratio of OH.sup.- /SiO.sub.2
shown above should furnish a pH of the system that broadly falls
within the range of about 9 to about 13.5. Advantageously, the pH
of the reaction system falls within the range of about 10.5 to about
11.5 and most preferably between about 10.8 and about 11.2.
Examples of materials affording silicon oxide useful in this invention
include silicic acid, sodium silicate, tetraalkyl silicates and
Ludox, a stabilized polymer of silicic acid manufactured by E. I.
DuPont de Nemours & Co. Typically, the oxide of boron source
is boric acid although equivalent species can be used such as sodium
borate and other boron-containing compounds.
Cations useful in formation of AMS-1B crystalline borosilicate
include alkali metal and alkaline earth metal cations such as sodium,
potassium, lithium, calcium, and magnesium. Ammonium cations may
be used alone or in conjunction with such metal cations. Since basic
conditions are required for crystallization of the molecular sieve
of this invention, the source of such cation usually is a hydroxide
such as sodium hydroxide. Alternatively, AMS-1B can be prepared
directly and more preferably in the hydrogen form by replacing such
metal cation hydroxides with an organic base such as ethylenediamine
as described in Published European Application No. 68796.
Organic templates useful in preparing AMS-1B crystalline borosilicate
include alkylammonium cations or precursors thereof such as tetraalkylammonium
compounds, especially tetra-n-propylammonium compounds. A useful
organic template is tetra-n-propylammonium bromide. Diamines, such
as hexamethylenediamine, can be used.
In a more detailed description of a typical preparation of this
invention, suitable quantities of sodium hydroxide and boric acid
(H.sub.3 BO.sub.3) are dissolved in distilled or deionized water
followed by addition of the organic template. The pH may be adjusted
between about 11.0.+-.0.2 using a compatible acid or base such as
sodium bisulfate or sodium hydroxide. After sufficient quantities
of a silica source such as a silicic acid polymer (Ludox) are added
with intensive mixing, preferably the pH is again checked and adjusted
to a range of about 11.0.+-.0.2.
Alternatively and more preferably, AMS-1B crystalline borosilicate
molecular sieve can be prepared by crystallizing a mixture of sources
for an oxide of silicon, an oxide of boron, an alkylammonium compound
and ethylenediamine such that the initial reactant molar ratios
of water to silica range from about 5 to about 25 preferably about
5 to about 20 and most preferably from about 10 to about 15. In
addition, preferable molar ratios for initial reactant silica to
oxide of boron range from about 4 to about 150 more preferably
from about 5 to about 80 and most preferably from about 5 to about
20. The molar ratio of ethylenediamine to silicon oxide should be
about above about 0.05 typically below 5 preferably between about
0.1 and about 1.0 and most preferably between about 0.2 and 0.5.
The molar ratio of alkylammonium compound, such as tetra-n-propylammonium
bromide, to silicon oxide can range from 0 to about 1 or above,
typically above about 0.005 preferably about 0.01 to about 0.1
more preferably about 0.01 to about 0.1 and most preferably about
0.02 to about 0.05.
The resulting slurry is transferred to a closed crystallization
vessel and reacted usually at a pressure at least the vapor pressure
of water for a time sufficient to permit crystallization which usually
is about 0.25 to about 20 days, typically is about one to about
ten days and preferably is about one to about seven days, at a temperature
ranging from about 100.degree. C. to about 250.degree. C., preferably
about 125.degree. C. to about 200.degree. C. The crystallizing material
can be stirred or agitated as in a rocker bomb. Preferably, the
crystallization temperature is maintained below the decomposition
temperature of the organic template compound. Especially preferred
conditions are crystallizing at about 165.degree. C. for about five
to about seven days. Samples of material can be removed during crystallization
to check the degree of crystallization and determine the optimum
crystallization time.
The crystalline material formed can be separated and recovered
by well-known means such as filtration with aqueous washing. This
material can be mildly dried for anywhere from a few hours to a
few days at varying temperatures, typically about 50.degree.-225.degree.
C., to form a dry cake which can then be crushed to a powder or
to small particles and extruded, pelletized, or made into forms
suitable for its intended use. Typically, materials prepared after
mild drying contain the organic template compound and water of hydration
within the solid mass and a subsequent activation or calcination
procedure is necessary, if it is desired to remove this material
from the final product. Typically, mildly dried product is calcined
at temperatures ranging from about 260.degree. C. to about 850.degree.
C., and preferably from about 425.degree. C. to about 600.degree.
C. Extreme calcination temperatures or prolonged crystallization
times may prove detrimental to the crystal structure or may totally
destroy it. Generally, there is no need to raise the calcination
temperature beyond about 600.degree. C. in order to remove organic
material from the originally formed crystalline material. Typically,
the molecular sieve material is dried in a forced draft oven at
165.degree. C. for about 16 hours and is then calcined in air in
a manner such that the temperature rise does not exceed 125.degree.
C. per hour until a temperature of about 540.degree. C. is reached.
Calcination at this temperature usually is continued for about 4
to 16 hours.
A catalytically active material can be placed onto the borosilicate
structure, either before or after incorporation into a matrix, by
ion exchange, impregnation, a combination thereof, or other suitable
contact means. Before placing a catalytically active metal ion or
compound on the borosilicate structure, the borosilicate should
be in the hydrogen form, i.e., HAMS-1B. If the sieve was prepared
using a metal hydroxide, such as sodium hydroxide, the hydrogen
form typically, is produced by exchange one or more times with ammonium
ion, typically using ammonium acetate, followed by drying and calcination
as described above.
The original cation in the AMS-1B crystalline borosilicate can
be replaced all or in part by ion exchange with other cations including
other metal ions and their amine complexes, alkylammonium ions,
ammonium ions, hydrogen ions, and mixtures thereof. Preferred replacing
cations are those which render the crystalline borosilicate catalytically
active, especially for hydrocarbon conversion. Typical catalytically
active ions include hydrogen, metal ions of Groups IB, IIA, IIB,
IIIA, VB, VIB, and VIII, and of manganese, vanadium, chromium, uranium,
and rare earth elements.
Also, water soluble salts of catalytically active materials can
be impregnated onto the crystalline borosilicate of this invention.
Such catalytically active materials include metals of Groups IB,
IIA, IIB, IIIA, IIIB, IVB, VB, VIB, VIIB, and VIII, and rare earth
elements.
Examples of catalytically active elements include ruthenium, rhodium,
iron, cobalt, and nickel. Mixtures of elements can be used. Other
catalytic materials include ions and compounds of aluminum, lanthanum,
molybdenum, tungsten, and noble metals such as ruthenium, osmium,
rhodium, iridium, palladium, and platinum. Other additional catalytic
materials can be ions and compounds of scandium, yttrium, titanium,
zirconium, hafnium, vanadium, niobium, tantalum, chromium, cerium,
manganese, cobalt, iron, zinc, and cadmium. Specific combinations
of nonnoble metals of Group VIII and other catalytic materials include
ions or compounds of nickel and osmium, nickel and lanthanum, nickel
and palladium, nickel and iridium, nickel and molybdenum, and nickel
and tungsten.
Ion exchange and impregnation techniques are well-known in the
art. Typically, an aqueous solution of a cationic species is exchanged
one or more times at about 25.degree. C. to about 100.degree. C.
A hydrocarbon-soluble metal compound such as a metal carbonyl also
can be used to place a catalytically active material. Impregnation
of a catalytically active compound on the borosilicate or on a composition
comprising the crystalline borosilicate suspended in and distributed
throughout a matrix of a support material, such as a porous refractory
inorganic oxide such as alumina, often results in a suitable catalytic
composition. A combination of ion exchange and impregnation can
be used. Presence of sodium ion in a composition usually is detrimental
to catalytic activity.
The amount of catalytically active material placed on the AMS-1B
borosilicate can vary from about 0.01 weight percent to about 30
weight percent, typically from about 0.05 to about 25 weight percent,
depending on the process use intended. The optimum amount can be
determined easily by routine experimentation.
The AMS-1B crystalline borosilicate useful in this invention is
admixed with or incorporated within various binders or matrix materials
depending upon the intended process use. The crystalline borosilicate
can be combined with active or inactive materials, synthetic or
naturally-occurring zeolites, as well as inorganic or organic materials
which would be useful for binding the borosilicate. Well-known materials
include silica, silica-alumina, alumina, magnesia, titania, zirconia,
alumina sols, hydrated aluminas, clays such as bentonite or kaolin,
or other binders well-known in the art. Typically, the borosilicate
is incorporated within a matrix material by blending with a sol
of the matrix material and gelling the resulting mixture. Also,
solid particles of the borosilicate and matrix material can be physically
admixed. Typically, such borosilicate compositions can be pelletized
or extruded into useful shapes. The crystalline borosilicate content
can vary anywhere from a few up to 100 wt. % of the total composition.
Catalytic compositions can contain about 0.1 wt. % to about 100
wt. % crystalline borosilicate material, and preferably contain
about 10 wt. % to about 95 wt. % of such material, and most preferably
contain about 20 wt. % to about 80 wt. % of such material.
The larger crystallite size borosilicate catalyst compositions
impregnated with a magnesium compound according to this invention
can be in powder form or already in extrudate form.
To make the larger crystallite size HAMS-1B crystalline borosilicate
molecular sieves of this invention, attention must be given during
the preparative process in solution to process variables. Slowing
or stopping the agitation during reactant addition and digestion
leads to larger sieve crystals, but the crystals are often too large,
poorly formed and occlude impurities if made in this way. Thus,
the agitation rate used in making the larger size crystallites is
generally not changed or changed only slightly from that used in
preparation of the standard size (0.2.mu. to 0.5.mu.) borosilicate
sieve.
Temperature is an influential factor in crystallite size and increasing
digestion temperature generally leads to larger crystallite size
crystalline borosilicates. Increasing the template [e.g. (Pr).sub.4
NBr] concentration generally also increases the crystallite size.
The water/SiO.sub.2 ratio can also be important and increasing the
dilution of the solids in the growth broth also generally increases
crystallite size.
In general, the process variables affecting crystallite size are
the same as those already known in the chemical arts and can be
relied upon by those skilled in the art to practice the invention
herein.
The standard crystalline borosilicate molecular sieves already
taught in the literature have a majority (greater than about 50
percent) of their crystallites in the range of about 0.2 micron
to about 0.5 micron and are more or less spherical in shape. The
larger crystallite size HAMS-1B borosilicates of use in this invention
have a majority of their crystallites in the range of about one
micron to about 15 microns. More preferably, the HAMS-1B borosilicates
of this invention have a majority of their crystallites in the range
of about 2 microns to about 10 microns and, most preferably, in
the about 4 micron to about 6 micron range. Since the crystallites
are three-dimensional, the crystallite size ranges given above refer
to the longest dimension of the crystal. Crystallite sizes are conveniently
measured using either optical microscopy or preferably, scanning
electron microscopy by tabulating the number of crystallites in
each size range over a small but representative sample of the borosilicate
sieve using photomicrography.
To make an impregnated catalyst composition of this invention,
a composition comprising the acid form of the crystalline borosilicate
molecular sieve, the majority of the crystallites of which are between
about 1 micron and about 15 microns, composited in an inorganic
matrix is contacted with a magnesium compound-containing solution.
The resulting mass is dried at temperatures up to about 150.degree.
C. driving off in this step essentially all of the impregnation
solvent. The resulting composition is then activated by calcination
for about 1 hour to about 24 hours at temperatures between about
300.degree. C. and about 800.degree. C., more preferably, about
4 hours to about 24 hours at a temperature between about 400.degree.
C. and about 600.degree. C.
The amount of magnesium incorporated with the catalyst composition
should be from about 4% to 25% by weight, more preferably, from
about 8% to about 15% by weight, percents calculated as percent
magnesium. The incorporated magnesium is believed to be present
substantially in the oxide form after heating.
Preferred magnesium compounds include most soluble magnesium salts,
more preferably, magnesium nitrate or acetate is used.
The solutions of magnesium compounds used in impregnation may be
made from polar or nonpolar solvents, including water and organic
solvents generally. Solvents that are destructive of either the
zeolite or matrix should be avoided. Water and alcohol are preferred
solvents.
Methylation of toluene in the presence of the above-described catalyst
compositions is effected by contact of the toluene with a methylating
agent, preferably methanol or dimethyl ether, at a temperature between
about 250.degree. C. and about 700.degree. C., and preferably between
about 400.degree. C. and about 600.degree. C. The reaction can take
place at atmospheric pressure, but the pressure may be within the
approximate range of about 1 atmosphere to about 2000 psig. The
molar ratio of methylating agent to toluene is generally between
about 0.05 and about 5 preferably about 0.1 to about 1. When methanol
is employed as the methylating agent a suitable molar ratio of methanol
to toluene has been found to be approximately about 0.1-2 mols of
methanol per mol of toluene. With the use of other methylating agents,
such as acetaldehyde, dimethoxyethane, acetone, and methyl halides,
the molar ratio of methylating agent to toluene may vary within
the aforenoted range.
Reaction is suitably accomplished utilizing a weight hourly space
velocity of between about 0.2 and about 500 and preferably between
about 1 and about 100. The reaction product consisting almost 100%
of para-xylene with small amounts of ortho- and meta-xylene together
with unreacted toluene and methylating agent may be separated by
any suitable means, such as fractional crystallization or distillation.
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 novel 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.
EXAMPLES
General
The reactions in the hydrocarbon conversion Examples below were
carried out in a stainless steel reactor of plug-flow design. A
4:1 ratio of toluene to methanol was fed at 0.21 ml per minute into
a preheater packed with inert Denstone packing and passed into a
1/2-inch O.D..times.5-inch reactor tube filled with about a 5 g
catalyst composition charge. The entire reactor and preheater assembly
was supported in a fluidized sand bath maintained at reaction temperature.
Product was collected in a cooled vessel as it dripped from the
reactor and analyzed by gas chromatography on a 60 meter fused silica
capillary column. All hydrocarbon isomer amounts are given in percents
by weight. All magnesium contents are given in weight percent of
the element.
EXAMPLE 1
Preparation of 1-2.mu. borosilicate molecular sieve was accomplished
using 2000 g of water, 79 g of ethylenediamine, 102 g of boric acid,
27 g of tetrapropylammonium bromide, and 666 g of Ludox HS-40.
The above reactants were mixed with the aid of a homogenizer and
then added to a 1-gallon autoclave whose impeller speed was set
at 500 rpm. The temperature was set at 145.degree. C. and the reaction
mixture digested until high crystallinity molecular sieve was obtained
(.ltoreq.4 days). The product was filtered, washed thoroughly with
deionized water, dried at 130.degree.-200.degree. C. for 16 hours,
and then calcined at 537.degree. C. for 12 hours.
EXAMPLE 2
Preparation of 4-5.mu. borosilicate molecular sieve was accomplished
by digesting a reaction mixture containing the following reactants:
2000 g of water, 79 g of ethylenediamine, 102 g of boric acid, 143
g of tetrapropylammonium bromide, and 666 g of Ludox HS-40.
The above reactants were mixed with the aid of a homogenizer and
then digested at 165.degree. C. in a 1-gallon autoclave whose impeller
speed was set at 500 rpm. The crystalline product, isolated after
3.5 days of reaction was filtered, washed thoroughly with deionized
water, dried at 130.degree.-200.degree. C. for 16 hours, and then
calcined at 537.degree. C. for 12 hours.
EXAMPLE 3
The preparation of 10-12.mu. borosilicate molecular sieve was carried
out in a similar manner to Example 2 except that 176 g of ethylenediamine
and 81 of tetrapropylammonium bromide were used. All other reagents
and amounts were as described in Example 2.
EXAMPLES 4-6
The procedure for preparing catalyst compositions from Examples
1-3 sieves was identical. A 30 g portion of the sieve was placed
in a blender with 45 Catapal.RTM. SB alumina, which is .alpha.-alumina
hydrate, .alpha.-Al.sub.2 O.sub.3.H.sub.2 O. To this mixture was
added 170 g of 5% acetic acid. The slurry was mixed at low speed
for one minute, then poured into a crystallizing dish and placed
into a drying oven at 130.degree. C. As the liquid evaporated, the
slurry was occasionally mixed. Drying was continued overnight, after
which the sample was placed in a calcining oven brought up to 537.degree.
C. over a period of about 3 hours and held at this temperature overnight.
Examples 4 5 and 6 catalyst compositions are made using 1-2.mu.,
4-5.mu. and 10-12.mu. sieve respectively.
EXAMPLES 7-9
The magnesium compound impregnation step was the same for the catalyst
compositions of Examples 4-6. A 9.0 g portion of catalyst composition
was placed in a solution of 12.5 of Mg(NO.sub.3).sub.2.6H.sub.2
O dissolved in 25 ml of water. This mixture was placed in a heated
shaker bath at 85.degree.-90.degree. C. and shaken for one hour.
The heater was then turned off and the shaking continued for an
additional 5 hours. Drying and calcination were carried out as described
in Examples 4-6. Each impregnated catalyst composition, Examples
7-9 contain about 11.5 percent magnesium calculated as the element.
EXAMPLE 10-17
Methylation of toluene with methanol was carried out as set forth
above under General using the unimpregnated catalyst compositions
containing 1-2.mu., 4-5.mu., and 10-12.mu. sieves, Examples 4 5
and 6. The data for these runs are tabulated in the Table below
as Examples 12 14 and 16. Examples 13 15 and 17 in the Table
are methylations carried out in the same way using methanol and
the impregnated catalyst compositions of Examples 7 8 and 9.
For additional comparison, a catalyst composition was made using
the procedure of Examples 4-6 employing the standard crystal size
borosilicate sieve (0.2-0.5.mu.). This composition was tested for
its ability to alkylate toluene before (Example 10) and after (Example
11) impregnation. Impregnation of the composition was carried out
as in Examples 7-9 and alkylation was carried out as is described
under General above. |