Note: Descriptions are shown in the official language in which they were submitted.
7~
Thls invention relates to an lmproved method ~or
syntheslzlng crystalllne aluminoslllcate zeclites requiring
a reactlon mixture for crystallization thereof which contains
an organic nitrogen-containing catlon source. Zeolites which
may be advantageously synthesized by the present improved method
lnclude, for ex~mple, ZSM-5, 2SM-ll, ZSM-12, ZSM-23, ZSM-34,
ZSM-35 and ZSM-38. Th~ present improved process requlres a
zeolite reaction mixture composltlon comprising an e~tremely
low mole ratio of hydroxide ions/sillca o~ only at most about
10-2, the presence of acid ions in amount less than the
equivalents of organic nitrogen present therein and a reaction
mlxture of pH o~ at least about 7.
This inventlon ~urther relates to an improved
crystalllne aluminosilicate zeolite produc' of the improved
method of synthesls and to organic compound conversion in the
presence of the improved zeolite as catalyst.
Zeolitic materials, both natural and synthetic~
have been demonstrated in the past to have catalytlc propertles
for various types of hydrocarbon conversions. Certain zeolitic
materials are ordered, porous crystalline aluminosillcates
having a de~inite crystalline structure within which there
are a large number of smaller cavities which may be inter-
cor.nected by a number of still smaller channels. Since the
-2-
dimensions of these pores are such as to accept for adsorptlon
molecules o~ certain dimensions while re~ecting those o~
larger dimenslons, these materials have come ~co be known as
"molecular sieves" an~ are utllized ln a variety of ways to
take advantage of these properkies.
Such molecular sieves, both natural and synthetic,
include a wide variety of posltive ion-contalnlng crystalline
aluminosilicates. These aluminosilicates can be described as
a rigid three-dimensional framework of SiO4 and A104 in which
the tetrahedra are cross lin~ed by the sharing of oxygen atoms
whereby the ratio of the total aluminum and silicon atoms to
oxygen is 1:2. The electro~alence of the tetrahedra containing
aluminum ls 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 ratlo of
aluminum to the number of various cations, such as Ca, Sr,
2 2
Na, K or Li is equal to unity. One type of cation may be
exchanged either entirely or partially by 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 aluminosilicate 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 aluminosilicates. A number of
these aluminosilicates require the presence of a source of
organic nitrogen-containing cations in the reaction mixture
used to prepare them. Those aluminosilicate zeolites include,
for example, zeolite ZSM-5 (U.S. Patent 3,702,886), zeolite
~7S~
ZSM-ll (U.S. Patent 3,709,979), zeolite ZSM-12 (U.S. Patent
3,832,449), zeolite ZSM-35 (U.S. Patent 4,016,245), zeolite
ZK-4 (U.S. Patent 3,314,752), zeolite ZK-22 (U.S. Patent
3,791,964), zeolite " alpha" (U.S. Patent 3,375,205), zeolite
"beta" (U.S. Patent 3,308,069), a synthetic erionite ~U.S.
Patent 3,699,139) and a synthetic offretlte (U.S. Patent
3,578,398).
Applicant knows of no prior art methods of
crystalline aluminosilicate zeolite synthesis, said synthesis
requiring a source of organlc nitrogen-containing cations
in the reaction mixture used therein, utilizing the present
improvement.
SUMMARY OF_THE INVENTION
An improved method for preparing an improved
crystalline aluminosilicate zeolite exhibiting enhanced
.purity as synthesized is provided which comprises forming a
reaction mixture containing one or more sources of an alkali
metal oxide, any organic nitrogen-containing oxides required
for preparation of the particular zeolite to be synthesized,
acid ions, an oxide of silicon, an oxide of aluminum and
water wherein the mole ratio of hydroxide ions/silica in said
reaction mixture is at most about 10-2, preferably from about
lO-l to about 10-2, and the acid ions are present in said reaction
mixture in amount less than the equivalents of organic
nitrogenpresent therein, and wherein the pH of said reaction
mixture is at least about 7, preferably from about 7 to ~bout
12, and maintaining the reactlon mixture at a temperature
and pressure for a time necessary to crystallize therefrom
said crystalline aluminosilicate zeolite.
--4--
Reaction condlt~ons ~nclude heating the reaction
mixture to a temperature of from about 70~ to a~out
500F for a per~od of time of ~rom about l hour to about
180 days. At a given reaction temperature, crystalllzation
time can be signiflcantly reduced from that required by the
prior art by the present improved method. Further, the
amount of organic nitrogen-containing cation source required
in the reaction mixture can be reduced from that required by the
prior art by the present improved method. Still further,
the crystalline aluminosilicate zeolite synthesized by the
present improved method can be of hi~her purity than normally
obtainable by prior art methods of synthesis.
.
DESCRIPTION OF SPECIFIC EMBODIMENTS
The present invention offers a means of synthesizing
improved crystalline aluminosilicate zeolites requiring
a reaction mixture for crystallization thereof which contains
a source of organic nitrogen-containing cations. Improved
zeolites which may be prepared in accordance herewith include,
for-example, ZSM-5, ZSM-ll, ZSM-12, ZSM-23, ZSM-34, ZSM-35
and ZSM-38.
1~7~Z
Zeolite zsM--5 and the conventional prepar~tion thereof
are described in U.S. Patent 3,702,886. Zeolite ZSM-ll
and the conventional preparation thereof are described in
U.S. Patent 3,709,979. Zeolite ZSM-12 and the conventional
preparation thereof are described in U.S. Patent 3,832,449.
Zeolite ZSM-35 and the conventional preparation thereof are
described in U.S. Patent 4,016,245.
Zeolite ZSM-23 and the conventional preparation there-
of are more particularly described in Canadian Patent
la 1,064,980. This zeolite can be identified, in terms of
mole ratios of oxides and in the anhydrous state, as
follows:
(o.58-3.4)M20 : A12O3 : (40-250)Sio2
where M is at least one cation and n is the valence
thereof. It will be noticed that the ratio of M2O may
n
exceed unity in this material. This is probably due to
the occlusion of excess organic species, used in the
preparation of ZSM-23, within the zeolite pores.
In a preferred synthesized form, zeolite ZSM-23 has a
2Q formula, in terms of mole ratios of oxides and in the
anhydrous state, as follows:
(0.5-3.0)R20 : (0.08-0.4)M20 : A12O3 : (40-250)SiO2
wherein R is an organic nitrogen-containing cation derived
from pyrrolidine and M is an alkali metal cation. It will
be noticed that in this preferred form the ratio of R2O
to A12O3 may exceed
~$ '
unity, probably due to the occlusion of eY.cess nitrogen-containing
organlc species (R20) within the zeolite pores.
The synthetic ZSM-23 zeollte possesses a definite
distinguishing crystalline structure whose X-ray di~fraction
pattern shows substantially the slgnl~icant lines set forth
ln Table I.
5~Z
TABLE I
_ _
d(A) I/Io
11.2 + 0.23 Medium
lO.l + 0.20 Weak
7.87 ~ 0.15 Weak
5.59 + 0.10 Weak
5.44 ~ 0.10 Weak
4.90 ~ 0.10 Weak
4.53 + 0.10 Strong
o 3 . go + o . o8 Very Strong
3. 72 + o.o8 Very Strong
3.62 + 0,07 Very Strong
3. 54 ~ o,07 Medium
3.44 ~ 0.07 Strong
3-36 + 0.07 Weak
3.16 + 0.07 Weak
. 3.05 + 0.06 Weak
2.99 + 0.06 Weak
2.85 + 0.06 Weak
.2.54 + 0.05 Medium
2.47 + 0.05 Weak
2.40 + 0.05 Weak
2.34 + 0.05 Weak
--8--
75i~
Zeolite ZSM~23 can be conventionally synthesized by
preparing a solutlon containing sources o~ an alkali metal oxide,
pre~erably sodium oxide, sources of nltrogen-contalning cation,
preferably pyrrolidine, an oxide of aluminum, an oxide of
silicon and water and having a composition, in terms of mole
ratios of oxides, ~alling within the following ranges:
R+
R~ ~ M~ 0.85 - 0.95
OH /SiO2 0.01 - 0.049
X2O/OH- 200 ~ 600
SiO2/A12O3 55 - 70
wherein R ls an organic nitrogen-contalning cation and M
is an alkali metal ion, and maintaining the mixture until
crystals of the zeolite are formed. The quantity of OH-
is calculated only ~rom the lnorganic sources of alkali
without any organic base contributlon. Thereafter, the
crystals are separated from the liquid and recovered.
Typical reaction conditions consist of heating the foregoing
reaction mixture to a temperature above 280F to about
400F for a period of time of from about 6 hours to about
14 days. A more preferred temperature range is from about
300F to about 375F with the amount of time at a temperature
in such range being from about 24 hours to about 11 days.
The digestion of the gel particles is carried out
until crystals form. The solid product is separated from
the reaction medium, as by cooling the whole to room temperature,
filtering and water washlng.
The crystalline product is dried, e.g. at 230F,
for from about 8 to 24 hours. Of course, milder conditions
may be employed if desired, e.g. room temperature under vacuum.
~7S~
Zeolite ZSM-34 and the conventional preparation
thereof are more partlc~llarly described in West German
Published Applica~ion No. 2,749,024. This zeolite can
be identified, in terms of mole ratios of oxides and in
the anhydro~s state, as follows:
(0.5-1.3)R20 : (0-0.15)Na20: (0.10-0.50)K20: A12O3: XSiO2
where R is the organic nitrogen-containing cation derived
from choline [(CH3)3N-CE~2CH2OH] and X is 8 to 50.
The synthetic ZS~-34 zeolite possesses a definite
1~ distinguishing crystalline structure whose X-ray diffrac-
tion pattern shows substasntially the significant lines
set forth in Table II.
- --10--
5~
TA3LE II
I/Io
11.5 ~ .2 Very S~rong
9.2 + .2 Weak
7.58 + .15 Medium
6.61 + .13 Strong
6.32 ~ .12 Weak
5.73 + .11 Medium
5.35 + .10 Weak
4.98 + .10 Weak
4.57 + .09 Strong-Very Strong
4.32 + .08 . Very Strong
4.16 ~ .08 Weak
3.81 ~ .07 Strong-Very Strong
3.74 + .07 Very Strong
3.59 + .07 Strong-Very Strong
3. 30 + . o6 Medium-Stron~
3.15 + .o6 Medium
2.92 + .05 Weak
2.85 + .05 Very Strong
2.80 + .05 Weak
2.67 ~ .05 Weak
2.52 ~ .05 Weak
2.48 + .05 Weak-Medium
2.35 + .04 Weak
2.28 + .04 Weak
L7~5~
zs~-34 can be convent~onally synthesized by preparing
a gel reaction mixture having a composition, in terms of
mole ratios of oxides, falling within the following ranges:
Broad Prefer~ed
___
SiO2/Al2O3 10-70 10-55
OH /SiO2 0O3-1.0 0.3-0.8
H2O/O~1 20-100 20-80
K20/M2o 0.1-1.0 0.1-1.0
R /R ~ ~l 0.1~0~8 0.1-0.50
where R+ is choline [(CH3)3N-CH2CH2OH] and M is ~la + K and
maintaining the mixture until crystals of the zeolite are
formed. The quantity of OH is calculated from inorganic
base (hyAroxide ion not neutralized by added mineral acid
or acid salt. Resulting zeolite crystals are separated and
recovered. Typical reaction conditons consist of heating
the foregoing reaction mixture to a temperature of from
about 80C to about 175C for a period of time of from
about 12 hours to 200 days. A more preferred temperature
range is from ahout 90 to 160C with the amount of time
at a temperature in such range being from about 12 hours
to 50 days.
The resulting crystalline product is separated from
the mother liquor by filtration, water washing and drying,
e.g., at 230F for from 4 to 48 hours. Milder conditions
may be employed, if desired, e.g., room temperature under
vacuum.
Zeolite ZSM-38 and the conventional preparation
thereof are more particularly described in U.S. Patent
4,046,859. This zeolite can be identified, in terms of
mole ratios of oxides and in thè anhydrous state, as
follows:
-12-
.. .
,,
7S~
(0-3 2-5)R20 : (0~0-B)M20 : Al203 : xS102
wherein x ls greater than 8, R ls an organic nitrogen-containlng
cation derived from a 2-(hydroxyalkyl) trialkylammonium
compound and ~ i5 an alkall metal catlo~, and is characterized
by a speclfled X-ray powder diffraction pattern.
In a preferred synthesized form, zeolite ZSM-38 has
a formula, in terms of mole ratios Or oxides and in the
anhydrous state, as follow~:
(o.4-2.5)R20 : (o-o.6)M2o : Al203 : ySiO2
wherein R is an organic nitrogen-containing cation derived
from a 2-(hydroxyalkyl) trialkylammonium compound, wherein
alkyl is methyl, ethyl or a combination thereof, M is an
alkali metal, especially sodiumg and y is from greater than
8 to about 50.
The synthetic ZSM-38 zeolite possesses a definite
distinguishing crystalline structure whose X-ray dlffraction
pattern shows substantially the significant lines set forth
in Table III.
~7
T,4EILE III
I/Io
9 . 8 * O . 20 StronG
9.1+ 0.19 ~ledium
5 8.o_ 0.16 Weak
7~ OD 14 kI9diUm
. 6.t7~ 0.14 ~edium
6 . 0~ 0.12 Weak
,,
4. 37+ 0. 09 Weak
4, 23* 0 . 09 ~Jeak
.ol + o.o8 Very Strong
3.81. ~ o.o8 ;: Very Strong
3. 69 ~ 0, 07 ~edium
3-57 ~ 0.07 . . Very Strong --
~3-51 ~ 0.07 . Very Strong
3~34 ~ 0~07 Medium
3.17 ~ o~o6 . Strong
3 . o8 ~ o ~ o6 : Medium
3.oo ~ o~o6 WeaX
2. 92 ~ 0,. o6 MedilLm
2 . 73 ~ o, o6 Weak
2 . 66 ~ 0. 05 Weak
2, 60 ~ 0. 05 ~Jeak
2.~'9 + 0.. 0~. Weak
,' . - ''' . ".
~14-
Zeolite ZS~-38 can be conventionally synthesized
by preparing a solutlon containlng sources of an alkali metal
oxide, preferably sodlum oxide, an organlc nitrogen-conkaining
oxide, an oxide of alumlnum, an oxide of sllicon and water and
havlng a composltion, in terms of mole ratios of oxides
falling within the following ranges:
Broad _ Preferred
R+/(R+ + M+)0.2 -1.0 0.3 -0.9
OH-/SiO2 0.05-0.5 0.07-0.49
H2O/OH- 41-500 100-250
SiO2/A1203 8.8 -200 12-60
wherein R ls an organlc nitrogen-contalning cation derlved
from a 2-(hydroxyalkyl) trialkylammonium compound and M is
an alkali metal ion, and maintaining the m~ture until crystals
of the zeolite are formed. Thereafter, the crystals are
separated ~rom the liquid and recovered. Typical reaction
conditions consist of heating the foregoing reaction mixture
to a temperature of from about 90F to about 400F for a
period o~ time of from about 6 hours to about 100 days. A more
preferred temperature range is from about 150~ to about
400F with the amount of time at a temperature in such range
being from about 6 hours to about 80 days.
The digestion of the gel particles is carried out
until crystals form. The solid product is separated from
the reaction medium, as by cooling the whole to room temperature,
filtering and water washing. The crystalline product is there-
after dried, e.g. at 230F for ~rom about 8 to 24 hours.
-15-
The values of Tables I, II and III were determined
by standard techniques. The radiation was th~ K-alpha doublet
of copper, and a Gelger counter spectrometer wlth a strip
chart pen recorder ~as used. The peak heights, I, and the
positions as a function of 2 times theta, where theta is the
Bragg angle, were read from the spectrometer chart. From
these, the relative intenslties, 100 I/Io, where Io is the
intensity of the strongest line or peak, and d(~), the
interplanar spacing in Angstrom units, corresponding to the
recorded lines, were calculated.
In the present improved method of zeolite synthesis,
a reaction mixture is formed containing one or more sources
Or alkali metal oxide, organic nitrogen-containing catlons,
acid ions, an oxide of silicon, an oxide of aluminum and water.
The composition of the reaction mlxture must contain hydroxide
ions and silica in the extremely low mole ratio of at most
about 10-2, preferably from about 10-1 to about 10-2. The
composition must also contain acid ions in amount less than the
equlvalents of organic nitrogen present therein. The reaction
mixture, further, must have a pH of at least 7, preferably from
about 7 to about 12.
The sources of alkali metal oxide may be, for
example J sodium, lithium or potassium hydroxides, oxides,
carbonates, halides (e.g. chlorides and bromides), sulfates,
nitrates, acetates, silicates, aluminates, phosphates and salts
of carboxylic acids.
The sources of organic nitrogen-containin~ cations,
depending, of course, on the particular zeolite product to
result from crystallization from the reaction mixture, may be
primary, secondary or tertiary amines or quarternary ammonium
compounds, examples of which include salts of tetramethylammonium,
-16-
~7.~
tetraethylammonium, tetraprop~lammonium, tetrabutylammonium,
dlethylammonlum, triethylammonium~ dibenzylammcnlum, dibenzyl-
dlmethylammonlum, dibenzyldiethylammonium, benzyltrimethyl-
ammonium and choline; or the compounds of trimethylamine~
trlethylamine, tripropylamine, ethylenediamine, propanediamine,
butanedlamine, pentanediamine, hexanediamlne, methylamine,
ethylamine, propylamine, butylamine, dimethylamine, diethylamine,
dipropylamine, benzylamine, aniline, pyridine,piperidine and
pyrrolidine.
The sources o~ acid ions may be, for example, HC1,
H2SO4, H3PO4, HNO3, carboxylic acids, aluminum sulfates, nitrates,
chlorides, phosphates or acid salts of primary, secondary or
tertiary amines.
Sources of silicon oxides may be, for example, silica
sols, alkali metal silicates, silica gels, siliclc acid or
aluminosilicates.
Sources of aluminum oxides may be, for example, alkali
metal aluminates, aluminum metal, hydrated aluminum oxides or
aluminum salts of acids such as H2SO4, HCl, HNO3 and ~he like.
In general, the reaction mixture for the present
improved synthesis process will have a composition, in terms
of mole ratios of oxides, as follows:
Broadly Most
Acce~table Pre~erred Preferred
_ _ _ _
SiO2/A12O3 5-1000 10-200 15-100
oH-/SiO2 10-1_lo-2 1o-7-lo-2 10-6_1o-2
H2O/siO2 5-200 10-100 10-100
M/SiO2 0.01-5.0 0.1-2.0 0.2-1.0
R/SiO2 0.01-3.0 0.04-2.0 0.1-1.0
3o wherein R is an organic nitrogen-containing cation or organic
nitrogen-containing cation source and M is an alkali metal ion.
-17-
~17S~lZ
Specifically~ when ZSM-5 is the desired zeolite
product Or the present lmproved synthesis process, the reactlon
mixture will have a composltion, in terms of mole ratios of
oxides, as follows:
S102/Alz03 ~ 5-1000
3H-/SiO2 = lo~10 ~0 2
H20/SiO2 = 5-200
M/SiO2 = 0.01-3.0
F~/S102 = O.01-1.O
wherein R is a tetrapropylammonium cation and M is an alkali
metal ion. The reaction mlxture must be malntained at a
temperature of from about 100F to about 400F for a period
of time of from about 3 hours to about 150 days until crystals
form. Thereafter, the crystals are separated from the reaction
medium and recovered. Separation may be accomplished by, for
example, cooling the whole to room temperature, filtering and
water washing.
When ZSM-11 is the desired zeolite product of the
present improved synthesis process, the reaction mixture will
have 2 composition, in terms of mole ratios of oxides, as
follows:
SiO2/A1203 = 10-180
OH-/SiO~ = lO-lO-lb-2
H20/SiOz ~ 5-100
M/SiO2 = 0.1-2.0
R/S102 = 0.04-1.0
~75~
whereln R is a tetrabutyla~nonium cation and M ls an alkali
metal ion. The reaction mixture must be maint2ined at a
temperature of from about 100F to about 400F for a period
of time o~ from about 4 hours ~o about 180 days until crystals
form. Thereafter, the crystals are separated from the reaction
medium and recovered. Separation may be accomplished by, for
example, cooling the whole to room temperature, filtering and
water washing.
When ZSM-12 is the desired ~eolite product of the
present improved synthesis process, the reaction mixture will
have a composition, in terms of mole ratios of oxides, as
follows:
SiO2/A1203 = 40-200
OH /SiO2 = lo~10_lo~2
H20/SiO2 = 5-100
M/S102 = 0.1-3.0
R/SiO2 ~ = 0.1-2.0
wherein R is a tetraethylammonium cation or a cation derived
from triethylamine and M is an alkali metal ion. The quantity
of hydroxide ions is calculated only from the inorganic sources
of alkali without any organic base contribution. The reactton
mixture must be maintained at a temperature of from about 100F
to about 400F for a period of time of from about 6 hours to
about 180 days until crystals form. Thereafter, the crystals
are separated from the reaction medium and recovered.
Separation may be accomplished by, for example~ cooling the
whole to room temperature, filtering and water washing.
--1--
7~
When ZSM-23 ls the desired zeolite product of the
present improved synthesis process, the reaction mixture will
have a composition, in terms of mole ratios of oxides, as
follows:
SiO2/A1203 = 10-200
OH /SiO2 = 10-1_lo-2
H2O/SiO2 = 5-100
M/SiO2 = 0.1-2.0
R/SiO2 = 0.1-1.0
wherein R is a cation derived from pyrrolidlne and M is an
alkali metal lon. The quantity of hydroxide ions is calculated
only from the inorganic sources of alkali without any organic
base contribution. The reaction mixture must be maintained
at a temperature Or from about 100~F to about 400F for a
period of time o~ from about 6 hours to about 180 days until
crystals form. Thereafter, the crystals are separated from
the reaction medium and recovered. Separation may be
accomplished by, for example, cooling the whole to room
temperature, filtering and water washing.
When ZSM-34 is the desired zeolite product of the
present improved synthesis process, the reaction mixture will
have a composition, in terms of mole ratios of oxides, as
follows:
SiO2/A1203 = 5-100
OH-/SiO2 = 1o~10_1o~2
H2O/SiO2 = 5-100
M/SiO2 = 0.1-2.0
R/SiO2 = 0.1-1.0
wherein R is a cation derived from choline and M is an alkali
metal ion. The reaction mixture must be maintained at a
-20-
temperature of from about 100F to abou~ 400F for a
period Or time of ~rom about 3 hours ~o about ].50 days until
crystals form. Thereafter, the crystals are separated ~rom
the reaction medium and recovered. Separation may be
accomplished by, for example, cooling the whole to room
temperature, filtering and water washing.
When ZSM-35 is the desired zeolite product of the
present improved synthesis process, the reaction mixture will
have a composition, in terms of mole ratios of oxides, as
lQ follows:
SiO2/Al203 = 8.8-200
OH-/SiO2 = 10-1_lo-2
H20/SiO2 = 5~100
M/SiO2 = 0.1-3.0
R/SiO2 = 0.05-2.0
wherein R is a cation derived from ethylenediamine or pyrrolidine
and M is an alkali metal ion. The quantity of hydroxide ions
is calculated only from the inorganic sources of alkali
without any organic base contribution. The reaction mixture
must be maintained at a temperature of from about 100F to
about 400F for a period of time of from about 6 hours to about
180 days until crystals form. Thereafter, the crystals are
separated from the reaction medium and recovered. Separation
may be accomplished by, for example, cooling the whole to room
temperature, ~iltering and water washing.
When ZSM-38 is the desired zeolite product of the
present improved synthesis process, the reaction mixture will
have a composition, in terms of mole ratios of oxides, as
follows:
-21-
7S~
SiO2/A12O3 - 8 . 8-200
OH-/3iO2 ~ 10-10 10-2
H2O/SiO2 = 5-100
M/SiO2 = 0.1-3. 0
R/SiO2 - 0.1-2. 0
s~
wherein R is derived from a 2-(hydroxyalkyl) trlalkylammCniUm
compound wherein alkyl is methyl, ethyl or a combination thereof,
and M is an alkali metal ion. The reaction mixture must be
maintained at a temperature o~ ~rom about 100F to about 400F
for a period o~ tlme o~ ~rom about 6 hours to about 180 days
until crystals form. Thereafter, the crystals are separated
~rom the reaction medium and recovered. Separation may be
accomplished by, for example, cooling the whole to room
temperature, filtering and water washing.
It is recalled that in calculating the mole ratio
of hydroxide ions/silica, it is conventional to calculate
hydroxide by summing moles o~ OH-, whether added as NaOH, as
quaternary ammonium hydroxide, as sodium silicate (NaOH + SiG2),
as sodium aluminate (NaOH + Al2O3), or the 1 ke, and to subtract
from that sum any moles o~ acid added. Acid m?y be added
simply as HCl, HNO3, H2SO4, acetic acid, and the like or it
may be added as an aluminum sulfate (A12O3 + H2SO4), chloride
(Al2O3 + HCl), nitrate (Al2O3 + HNO3), etc. I~ particular,
no contribution is assigned to organic bases such as amines
ln this calculation.
Although the usefulness of this invention is to be
~ound with quaternary ammonium cations at OH-/Si02 ratios
below those recognized earlier, it is with theaminesthat this
invention is ideally suited. Amines present in reaction mixtures
having an 0H~/SiO2 ratio o~ 0.01 are protonated when further
acid is added. Until said additlonal acid exceeds the amine
present, the pH remains above 7.
-23-
~1~7S~
In a conventional calculation which does not
consider amlnes, the total moles of acid could thereby
exceed the moles of hydroxlde added in said reaction
mixture and subtraction would thereby lead to apparent
"ne~atlve" OH /S102 ratios. A negative ratio is, of
course, not possible since the true moles of hydroxide
(per liter) in an aqueous mixture are always positlve and
equal to 10-14 divided by the moles per liter of acid.
Calculated from the krue moles of hydroxlde, the present
invention would include an OH /SiO2 range of about 10 10
to about 10-2. Maintaining the convention which has been
established in describing reaction mixture compositions,
we define the quantity of acid added in excess of the
hydroxide added by the ratio H~(additional)/SiO2.
The improved zeolites prepared by the present
improved method may be used for organic compound conversion
-24-
~75~:
in the hydrogen form or they may be base exchanged or
impregnated to co~tain a~monium or 2 metal catlon complement.
It is desirable to calcine the cataiyst after base e~change.
The metal cations that may be present include any G~ the
cations o~ the metals o~ Groups I through VI~I of the PerioGic
Table, especiaIly rare earth metals. However~ in the case Or
Group IA metals, the cation content should ln no case be so
large as to effectively inactivate the catalyst.
- As in the case Or many catalysts, it is desirable
to incorporate the improved catalyst prepared by the present
improved method with another material resistant to the temperature
and other conditions employed in some organic compound conversion
processes. Such matrix materials i~clude active and inactlve
materials and synthetic or naturally occurring zeolites as well
as inorganic material such as clays, silica and/or metal oxides.
The latter may be either natur lly occurring or in the form of
gelatinous precipitates, sols or gels including mixtures o~
silica and me~al oxides. Inactive materials suitably~ serve as
diluents to control the amount of conversion in a given process
so that products can be obtained econom~cally and orderly
without employing other means ~or controlling the rate of
reaction. Frequently, zeolite materials have been incorporated
into naturally occurring clays, e~.g. bentonite and kaolin.
These materials, i.e. clays, oxides, etc., function, in part,
as binders for the catalyst. It may be desirable to provide
a catalyst having good crush strength so it may be used in a
process where the catalyst is subjected to rough handling,such
as in a ~luidized system, which may tend to break the catalyst
down into powder-like materials which cause problems in
processing.
-25-
1~75~
~aturally occurring clays which can be composited
with the i~lproved zeolites pr~pared hereby include the
montmorillonite and kaolin families, which include the
su~-bentonites and the kaolins com~only kno~:n as Dixie,
McNammee, Georgia and Florida clays or others in which the
main mineral cons~ituent is halloysite, kaolinite, dickite,
nacrite or anauxite. Such clays can be used in the raw
state as originally mined or initially sub~ected to calcination,
acid treatment or chemical modification.
In addition to the foregoing materials, the zeolites
made hereby can be composited ~Jith one or more porous matrix
materials such as alumina, silica-alumina, sllica-mag~esla, silica-
zirconia, silica-thoria, silica-beryllia, sillca-titania,
titania-zirconia as well as ternary compositions such as
silica-alumina-thoria, silica-alumina zirconia, silica-alumina-
magnesia and sllica-magnesla-zirconia. The matrix can be in
the form o~ a cogel. A mixture of these components, one w1th
the other and/or wlth a clay, could also be used. The relati~e
proportions of zeolite and inorganic oxide gel matrix and/or
clay vary widely with the crystalline aluminosilic~te content
ranging from about 1 to about 90 percent by weight a~d more
usually in the range of about 2 to about 50 percent by weight
of the composite.
Zeolites prepared by the present improved method
are valuable catalysts in ~arious organic compound, e.g.
hydrocarbon compounds and oxygenates such as methanol,
conversion processes. Such processes include, for example,
alkylation of aromatics with olefins, aromatization o~ normally
gaseous olefins and paraffins, aromatization f normally
liquid low molecular weight parrafins 2nd olefins, isomerization
of aromatics~ paraffins and ole~ins, disproportion2tion o
aromatics, transal~:ylation of 2romatics, oligo~eri~tion o~
-26-
~75~Z
ole~ins and crackin~ and hydrocracking. All o~ ~he 1 ore~oin~
catalytic processes are of value since they result in upgra~ing
ol the organic charge being processed.
The process rOr upgrading re~ ormates ~rherein a zeolite
prepared in accordance herewith is employed as catalyst ~enerally
involves contact during processing with a refor~ate or refor~.er
-27-
effluent, wlth or withou~ added hydrogen, at a temperature
bet~een 500F and about 1100F and prerer~bly between about
550F and about 1000F. The reaction pressure in such
operation is generally wi~hin th~ range of about 25 and about
Z000 psig and pre~erably about 50 to aboùt 1000 psig. The
liquid hourly space velocity, i.e. the liquld volume o~
hydrocarbon per hour per volume of catalyst, is between about 0.1
and about 250, and preferably between about 1 and 100. Although
hydrogen is not essential to this process, when it is used the
molar ratio of hydrogen to hydrocarbon charge employed is
between about 0.1 and about 80 and preferably between about 1
and about 10.
Oligomerization of ole~ins, i.e. olefins having
2 to 10 carbon atoms, is effectively carried out with t~e
zeolite prepared in accordance herewith 25 catalyst. Such
- reaction is suitably effected at a temperature between about
550F and about 1150F, a pressure between about 0.01 and
about 1000 psig utilizing a weight hourly space velocity
within the approximate range o~ 0.1 to 1000.
Alkylation of aromatic hydrocarbons, e.g. benzene,
with an alkylating agent such as an alkyl h21ide, an alcohol
or an olefin,~is also readily e~fected in the presence of the
presently made zeolite as catalyst with reduced agin~.
Alkylation conditions include a temperature between about
400F and about 1000F, a pressure between about 25 and about
1000 psig utilizing an aromatic hydrocarbon/alkylating agent
mole ratio of 2 to 200 and an alkylatin~ agent weigh~ hourly
space velocity within the approximate range of 0.5 ~o 50.
-28-
a75~;~
Xylene isomer~zat~on is another reactiun suitably
condllcted in the presence of the zeolite made in accord2nce
here~lth as catalyst. Isomeriza~o~ ccnditions include a
tempe~ature between about 300F and about 900F, a pressure
between about 25 and abou~ 1000 psig utilizing a wei~ht
hourly space veloc~ty within the approximate range of 0.2
to 100.
Aromatics, such as, for example, toluene, ~ay be
disproportionated in the presence of the presently made
zeolite under a temperature of from about 450F to about 1100F,
a pressure of from about 50 psig to about 800 psig and a liquid
hourly space velocity within the approximate range of about
0.1 to about 20. Aliphatic hydrocarbons may also be disp~o-
portionated in the presence of zeolite prepared by the present
improved method at a temperature of from about 350F to about
900F, a pressure between 0 and 3,000 psig and a liquid hourly
space velocity of between about 0.01 and about 5.
When the conversion of organic compounds with the
presently made zeolite 2S catalyst is cracking, catalytic
conversion condltions should be maintained within certain
ranges, including a tempera~ure of from about 700F to about
1200F, preferably from about 800F to about 1000F, a pressure
of from about atmospheric to about 200 psig, and a liquid
hourly space velocity of from about 0.5 hr 1 to about 50 hr 1,
pre~erably from about 1 hr 1 to about 10 hr 1 When the
conversion is hydrocracking, catalytic conversion conditions
should be maintained within some~lhat different ranges, including
a temperature of from about 400F to about 1000F, preferably
from about 500F to about 850F, a pressure of from about
500 psig to about 3500 psig, a liquid hourly space velocity
-29-
of from about 0.1 hr~l to about 10 hr-l, pre~erably ~rom about
0.2 hr~l to about 5 hr~l, and a hydrogen/hydrocarbon ratio
of from about 1000 sc~/bbl to about 20,000 sc~/bbl, preferably
from about 3,000 scf/bbl to about 10,000 scf/bbl.
It may be desirable ln some lnst~nces to add a
hydrogenation/dehydrogena~ion component to the zeolite prepared
in accordance herewith ~or use as catalyst. The amount of the
hydrogenation/dehydrogenation component employed is not
narrowly critical and can range rrom about 0.01 to about 30
welght percen~ based on the entire catalyst. A variety of
hydrogenation components may be combined with either the
zeolite and/or matrix in any feasible manner which affords
intimate contact of the components, employing well known
techniques such as base ex~hange, impregnation, coprecipitatlon,
cogellation, mechanical admixture of one component with the
. other and the like. The hydrogenation component can include
~30-
7~
metals, oxldes and sul~ides o~ metals o~ the Periodic Table
~hich fall in Group VI-3 lncluding chromium~ molybdenum,
tungsten and the like; Group II-B including zinc and cadmium;
Group VIII including cobalt, nickel, platinum, palladium,
ruthenium, rhodium, osmium and irldium; Group IV-A such as
germanium and t~n and combinations of metals, sulfides and
oxides Or ~etals of Group VI-~ and VIII, such as nickel-
tungsten~sulfide, cobal~ oxide-molybdenum oxide and the like.
Pre-treatment before use varies depending on the hydrogenation
component present. For example, with components such as
nickel-tungsten, cobalt-molybdenum, platinum and palladium,
the catalyst may desirably be sulfided. With metals like
platinum or palladlum, a hydrogenation step may also be
employed. These techniques are well known in the art and
are accomplished in a conventional manner.
In order to more fully illustrate the nature of
the invention and the manner o~ practicing same, the ~ollowing
examples are presented.
-31-
7~
Exam~_e 1
In accordance with the prior art m~thod o~
preparing zeolite ZSM-5, to a solution o~ 63.3 grams
Q-brand sodium sillca (28.5 wt. % SiO2, 7.75 wt. %
Na20 and 63.75 wt. % H20) in 79.2 grams o~ water in a
polypropylene bo~tle was added a solu~ion of 2.05 grams
A12(S04)3-16H20, 3.8 grams H2S04 and 7.85 grams tetrapropyl-
ammonium bromlde in 108.3 grams of water. A~ter vigorous
mixing the pH o~ the mixture was measured to be ~ 10.
The bottle was placed in a steam chest at 90-95C.
The reaction mlxture ha~ a molar composition as ~ollows:
SiO2/A1203 = 92
OH-/SiO2 = 0.20
H20/SiO2 = 42
~/S102 ~ 0.53
R/S102 = 0.10
After 30 days, a sample of the gel was taken, washed with
water, and dried. An X-ray diffraction pattern showed the
sample to contain about 40% ZSM-5 together wlth amorphous
material.
ExamPle ?
In accordance wlth the present improved method of
preparing zeolite ZSM-5, to a solution of 63.3 grams Q-brand
sodium sllicate ln 79.2 grams o~ water in a poIypropylene
bottle was added a solution o~ 2.05 grams A12(S04)3-16H20,
7.2 grams H2S04 and 7.85 grams tetrapropylammonium bromide
in 108 . 3 grams o~ water. The acid ions in this reaction mixture
were present in amount suf~icient to reduce the OH-/SiO2
~7~
r~tio below lo-2. A~ter vigorous mlxin~ the pH was determined
to be 7. The bottle was then placed in a steam chest at
90-95C. I~e reaction mlxture had a molar composition as
follows.
SiO2/A12O3 = 92
OH /SlO2 = ~10-2
H2O/SiO2 = 42
M/SiO2 = 0.53
R/SlO2 = 0.10
Although successful crystallization was noted earlier, the
product ZSM-5 was removed, washed, and dried after 30 days
in the steam chest. The X-ray di~raction pattern showed
100~ ZSM-5. Scanning electron micrograms showed the material
to be relatively uniform crystals of 6-12 micron diameter.
Examples 3-6
In these exampies, prior art and present improved
, methods of syntheses of zeolite ZSM-35 were conducted.
¦ Crystallization at 100C was conducted in polypropylene
bottles under static conditions in a steam chest. The slIicate
source was Q-brand (27.8% SiO2, 8.42% Na2O) and the alumina
source was A12(SO4)2 16H20. The organic nitrogen-containing
cation source was pyrrolidine. Reaction mixture compositions
(mole ratios), total days in a steam chest ~or crystalli~ation to
occur and zeolite product compositions are tabulated in Table IV,
hereinafter presented. It is observed from these examples
that prior art methods (Ex2mples 5 and 6) ~ail to compare favorably
with the present improved method of synthesis ~Examples 3 and 4)
-33-
for zeol~te ZSM-35. After only 35 and 39 days ln the steam
chest, 100% ZSM-35 was obtained from the improved methcd of
Examples 3 and 4. After as many as 85 days in the steam
chest for the reactlon mixture of Example 5, the product
contained 50% ZSM-35 and 50~ mordenite. ~fter 70 days in the
steam chest for the reaction mixture of Example 6, only
10% ZSM-35 resulted.
-34-
z
tU ~ 3 3
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OO O O
P::
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O ~1
U~ ~
~q O ~1 0
O rl
~ ~ O O O O
~O~ ~
~ _~
:~ ~9
H rl N
:~: o c~
~ ~ L~
m o z o o o o
.- ~d
~: o
~ ~ ~ o~
V~ I I ~U
o o
o o
. o ~O
o~l
v~ c~ o
3 ~r
N
O O O O
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U~
'3 ' .
t~ tr ) 3 Lt'~
?e
-35-
I Lr\ U~
,_ ~ ,~
o ~
c~ ~ 3 ~ ~ ~
~ :. O O V
. ` ,~ E
E~ J ~ ~
_~ ~ ~ I I ~d
h
_
r~l
~ Cr~
O
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r~
t'~
~X U~ ,.
~Q ~ ~ ~ ~
o o ~ ~a ~1
o o o c:~ o a~
O
Il
,~
~d ~ J L~
-36-
S~
Example 7
A sample of crystalllne alumlnosillcate zeollte
ZSM-5 prepared as ln Example 2 was evaluated for catalytlc
activity with a flve-component feedstock of n-hexane, 3-
methylpentane, 2,3-dimethylbutane, benzene and toluene at
2Q0 psig, a weight hourly space velocity (WHSV) o~ 2.9 hr-l,
a temperature of 427C and a hydrogen/hydrocarbon mole
ratio of 3.6. This zeolite, after exchange, provided 94%
conversion of n-hexane and 46% conversion o~ 3-methylpentane.
Of the converted paraffln charge, 11% reacted with benzene
and toluene to produce alkyl aromatics.
ExamE~e_8
A sample of ZSM-35 was prepared as in Example 3,
but at a temperatur.~ of 160C and with R/SiO2 = 0.14 and
H+(additional)/SiO2 = 0.03. The ZSM-35 product was evaluated
for catalytic activity with a ~eedstock as in Example 7.
Test conditions were 200 psig, 3.2 hr 1 WHSV, 427C and
a hydrogen/hydrocarbon mole ratio of 4.8. Thls ZSM-35
converted 96% n-hexane and 20% 3-methylpentane.
.
-37~
