U.S. patent application number 16/410084 was filed with the patent office on 2019-08-29 for process for preparing a mesoporized catalyst, catalyst thus obtained and use thereof in a catalytic process.
This patent application is currently assigned to TOTAL RAFFINAGE FRANCE. The applicant listed for this patent is TOTAL RAFFINAGE FRANCE. Invention is credited to Nadiya DANILINA, Delphine MINOUX.
Application Number | 20190262810 16/410084 |
Document ID | / |
Family ID | 47143871 |
Filed Date | 2019-08-29 |
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United States Patent
Application |
20190262810 |
Kind Code |
A1 |
MINOUX; Delphine ; et
al. |
August 29, 2019 |
PROCESS FOR PREPARING A MESOPORIZED CATALYST, CATALYST THUS
OBTAINED AND USE THEREOF IN A CATALYTIC PROCESS
Abstract
A hydroconversion catalyst obtained by the process described,
comprising a mesoporized zeolite with healed zeolitic structure,
containing at least one network of micropores and at least one
network of mesopores, having an atomic Si/Al ratio within the
zeolite framework of greater than or equal to 2.3 and showing
reduced amount of extra-framework aluminium with regard to that of
a mesoporized zeolite with no healed zeolitic structure.
Inventors: |
MINOUX; Delphine; (Nivelles,
BE) ; DANILINA; Nadiya; (Uccle, BE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TOTAL RAFFINAGE FRANCE |
Courbevoie |
|
FR |
|
|
Assignee: |
TOTAL RAFFINAGE FRANCE
Courbevoie
FR
|
Family ID: |
47143871 |
Appl. No.: |
16/410084 |
Filed: |
May 13, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14347159 |
Mar 25, 2014 |
10343150 |
|
|
PCT/EP2012/071017 |
Oct 24, 2012 |
|
|
|
16410084 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01J 29/043 20130101;
B01J 29/072 20130101; C10G 49/08 20130101; B01J 29/126 20130101;
B01J 35/002 20130101; B01J 29/076 20130101; C10G 45/62 20130101;
B01J 29/146 20130101; B01J 2229/14 20130101; B01J 29/084 20130101;
B01J 29/90 20130101; C01B 39/06 20130101; C07C 2529/068 20130101;
C10G 47/16 20130101; B01J 2229/37 20130101; B01J 38/08 20130101;
Y02P 20/584 20151101; B01J 2229/186 20130101; B01J 2229/42
20130101; C10G 47/18 20130101; B01J 2229/22 20130101; B01J 2229/16
20130101; C07C 4/06 20130101; B01J 2229/38 20130101; C10G 45/64
20130101; C01B 39/026 20130101; B01J 29/06 20130101; B01J 29/166
20130101; B01J 35/1095 20130101; C01B 39/24 20130101; B01J 29/068
20130101; B01J 35/108 20130101; B01J 2229/36 20130101; B01J 35/109
20130101; B01J 37/06 20130101 |
International
Class: |
B01J 29/12 20060101
B01J029/12; B01J 38/08 20060101 B01J038/08; B01J 35/10 20060101
B01J035/10; B01J 29/068 20060101 B01J029/068; B01J 29/072 20060101
B01J029/072; B01J 29/076 20060101 B01J029/076; B01J 29/08 20060101
B01J029/08; B01J 29/14 20060101 B01J029/14; B01J 29/16 20060101
B01J029/16; B01J 35/00 20060101 B01J035/00; B01J 37/06 20060101
B01J037/06; C07C 4/06 20060101 C07C004/06; C10G 49/08 20060101
C10G049/08; C01B 39/24 20060101 C01B039/24; C01B 39/06 20060101
C01B039/06; B01J 29/90 20060101 B01J029/90; C01B 39/02 20060101
C01B039/02; B01J 29/06 20060101 B01J029/06 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 24, 2011 |
FR |
11 59618 |
Dec 29, 2011 |
FR |
11 62520 |
Claims
1. A hydroconversion catalyst comprising a mesoporized zeolite with
healed zeolitic structure, containing at least one network of
micropores and at least one network of mesopores, having an atomic
Si/Al ratio within the zeolite framework of greater than or equal
to 2.3 and showing reduced amount of extra-framework aluminium with
regard to that of a mesoporized zeolite with no healed zeolitic
structure, wherein the hydroconversion catalyst is obtained by a
process for preparing a catalyst comprising a mesoporized zeolite,
including the steps of: A) preparation of a protonic mesoporized
zeolite, which contains at least one network of micropores and at
least one network of mesopores, and B) treatment in a gas or liquid
phase containing ammonia or ammonium ions to obtain the
catalyst.
2. A process for the hydroconversion of a hydrocarbon feedstock,
wherein said feedstock to be treated is placed in contact with a
catalyst obtained by a process for preparing a catalyst comprising
a mesoporized zeolite, including the steps of: A) preparation of a
protonic mesoporized zeolite, which contains at least one network
of micropores and at least one network of mesopores, and B)
treatment in a gas or liquid phase containing ammonia or ammonium
ions to obtain the catalyst.
3. A process for the hydroconversion of a hydrocarbon feedstock,
wherein said feedstock to be treated is placed in contact with the
hydroconversion catalyst according to claim 1.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of U.S.
application Ser. No. 14/347,159, filed on Mar. 25, 2014, which is a
National Stage of International Application No. PCT/EP2012/071017
filed Oct. 24, 2012, claiming priority based on French Patent
Application No. 11 59618 filed Oct. 24, 2011 and French Patent
Application No. 11 62520 filed Dec. 29, 2011, the contents of all
of which are incorporated herein by reference in their
entirety.
[0002] The invention relates to a process for preparing a
mesopores-containing catalyst, the catalyst thus obtained and the
use of the catalyst thus obtained in an industrial process.
[0003] The catalyst described here comprises a mesoporized zeolite
and may be used in many hydroconversion processes, in particular,
in the hydrocracking process.
PRIOR ART
[0004] The various zeolites are distinguished by different
structures and properties, and are well known in the art. A few
structures commonly used in the field of catalysis are disclosed in
WO2010/072976, among them some are given below.
[0005] Zeolite Y (FAU) is a three-dimensional zeolite with large
pores, whose structure has large cavities interconnected by
channels formed from 12-membered rings, each ring presenting 12
(Si.sup.4+ and Al.sup.3+) cations and 12 O.sup.2- anions.
[0006] Beta zeolite (BEA) is a three-dimensional zeolite with large
pores comprising pores formed from 12-membered rings in all
directions.
[0007] Zeolite ZMS-5 (MFI) is a virtually three-dimensional zeolite
with medium-sized pores, comprising pores formed from 10-membered
rings in one direction that are interconnected by zig-zag channels
formed from 10-membered rings (this is why this structure is
considered as being virtually three-dimensional).
[0008] Mordenite (MOR) is a zeolite with large pores formed from
12-membered rings, with channels extending in only one direction
and which has between these channels small pockets formed from
8-membered rings.
[0009] Ferrierite (FER) is a two-dimensional zeolite with
medium-sized pores comprising main channels formed from 10-membered
rings, which are interconnected via side channels formed from
8-membered rings.
[0010] Zeolites are important catalytic materials and widely used
in acid-catalyzed reactions such as cracking (e.g. hydrocracking,
FCC, olefin cracking), isomerization reactions (e.g. of paraffins
and olefins) and more recently, methanol conversion technologies
(e.g. MTO, MTP, MTG). For all these reactions, the zeolite is the
heart of the catalyst, rendering high catalytic activity, high
stability, and last but not least high product selectivity, induced
by the microporous zeolite structure. Notwithstanding the positive
effect of the presence of micropores with respect to shape
selectivity, the micropores may also have a negative impact, which
is often illustrated by the low rate of access of molecules into
the zeolite crystals, or unwanted adsorption effects of reactants
and/or products during the catalytic action. These steric
constraints decrease the accessibility of the zeolite micropore
volume during the catalytic action, and it can be stated that the
zeolite crystals are not always being used effectively.
[0011] One of the important issues in the development of new
zeolite catalysts is the guarantee of sufficient accessibility of
the active sites for reactant and/or product molecules, thereby
maximizing the effectiveness of the catalyst. The straightforward
solution to minimize diffusion limitation would be the reduction of
the intracrystalline diffusion pathlength. One possibility is to
decrease the zeolite crystal size. Another strategy, to obtain
materials with sufficient accessibility is the creation of a
secondary pore system consisting of mesopores (2-50 nm) inside the
microporous zeolite crystals. Traditionally, mesopores are
introduced into zeolites and zeolite-like crystals by
dealumination, using hydrothermal treatment such as steaming [U.S.
Pat. Nos. 3,293,192, 3,506,400, and 5,069,890], and acid leaching
techniques [U.S. Pat. Nos. 3,506,400, 4,093,560, and 5,601,798].
Alternatively, chemical treatments, with for example EDTA [U.S.
Pat. Nos. 3,506,400 and 4,093,560] or (NH.sub.4).sub.2SiF.sub.6
[EP0082211], have been proposed as well. A more detailed literature
review on the generation of mesopores in zeolites by various
methods, was presented by van Donk et al. [S. van Donk et al.,
Catalysis Reviews 45 (2003) 297].
[0012] Despite of the considerable developments over the last years
in the domains of the synthesis, characterization and comprehension
of the formation mechanisms of these structured mesoporous
materials, their effective application in industry is still highly
limited because of their high cost, which is partially related to
the high cost of the organic template. Therefore, from a cost
perspective, the classical hydrorthermal and acid leaching
techniques remain highly attractive, which explains why they are
largely used today in industry. However, the introduction of
mesopores by these ways is not easily controlled and often
materials are obtained with a random and non-optimized
mesoporosity. In a paper by Janssen et al. [A. H. Janssen et al.,
Angew. Chem. Int. Ed. 40 (2001) 1102], it was demonstrated using
three-dimensional electron microscopy that a large part of the
mesopores in a commercially available steamed and acid-leached
zeolite Y (CBV780, Zeolyst Int.) were cavities, not optimally
connected to the outer surface of the zeolite crystal. Obviously,
for catalysis, a system of interconnected cylindrical mesopores is
expected to enhance the accessibility for reactants and the
diffusion of reaction products much more than mesoporous cavities
inside the crystal.
[0013] In recent years, as an alternative to the classical
hydrorthermal and acid leaching of the as-synthesized zeolite
material, another approach for the formation of mesopores has been
proposed [M. Ogura et al., Chem. Lett. (2000) 82; M. Ogura, Appl.
Catal. A Gen. 219 (2001) 33; J. C. Groen et al., Microporous
Mesoporous Mater. 69 (2004) 29; J. C. Groen, et al., J. Phys. Chem.
B, 108 (2004) 13062]. This alternative method is based on the
careful desilication of the as-synthesized zeolite by a treatment
in an alkaline medium. This technique was firstly explored in the
late 1980's for studying dissolution phenomena and structural
changes in zeolite Y and ZSM-5. Furthermore, two patents were
assigned to Shell on the modification of ultra-stable and very
ultra-stable Y-zeolites with a Si/Al ratio between 2 and 12.5 at/at
[EP0528494] and their application in a hydrogenation process
[EP0519573].
[0014] Recently, the Applicant has disclosed in the patent
application WO 2010/072 976 a modified zeolite Y prepared by
careful desilication of a dealuminated faujasite, resulting in a
material which had a unique trimodal system of intracrystalline and
interconnected pores. This zeolite showed an improved performance
in several hydrocracking reactions, being more selective to middle
distillates and suppressing overcracking. Middle distillates
comprise a range of products from the middle boiling fraction of
the crude oil barrel.
[0015] Hydrocracking reactions are gaining on importance with the
need to treat heavier and more polluted feedstocks and with an
increasing demand for middle distillates in Europe. Therefore, a
middle distillates-selective hydrocracking catalyst is seeked.
[0016] However, often the activity of mesoporous catalysts
synthesized by the destructive techniques is significantly lower
compared to the catalysts based on the purely microporous zeolites.
The improvement in diffusivity of the mesoporous zeolites is often
reached by the loss of long-range crystallinity, microporosity,
amount of framework aluminum and the closely associated amount of
Bronsted acid sites. These characteristics are often responsible
for the activity of the catalyst, particularly, in acid-catalyzed
reactions. The change in aluminum coordination alters the number of
Bronsted acid sites in the catalyst, which is directly related to
the catalytic activity [N. Katada et al., Micropor. Mesopor. Mater.
75 (2004) 61].
[0017] In zeolite beta, octahedrally coordinated aluminum forms and
can be converted to tetrahedral aluminum by adsorption of basic
molecules, such as ammonia, as well as by substitution of the
protons by sodium and potassium cations [E. Bourgeat-Lami et al.,
Appl. Catal. 72 (1991) 139]. The presence of aluminum species that
reversibly convert coordination on ammonia adsorption was also
found in the zeolites ZSM-5 [G. L. Woolery et al., Zeolites 19
(1997) 288], MOR [A. Omegna et al., J. Phys. Chem. B. 107 (2003)
8854] and Y [B. H. Wouters et al., J. Am. Chem. Soc. 120 (1998)
11419; B. Xu et al., J. Catal. 241 (2006) 66]. Similar behavior was
observed in amorphous silica aluminas [A. Omegna et al., J. Phys.
Chem. B. 107 (2003) 8854]. In acidic zeolites, the transformation
of the coordination of aluminum from tetrahedral to octahedral
occurs at room temperature after contact with moisture; at
temperatures above 400 K, octahedral coordination is unstable [J.
A. van Bokhoven et al., J. Am. Chem. Soc. 125 (2003) 7435] and
reverts back to tetrahedral coordination, although the Bronsted
acid site is not restored [A. Omegna et al., J. Phys. Chem. B. 107
(2003) 8854].
[0018] Therefore, to combine the diffusional advantages of the
mesoporous structure with the preserved zeolitic properties, a
post-synthesis treatment after the introduction of mesopores should
be considered. Such a post-synthesis treatment could help healing
the partially destroyed zeolite structure by re-inserting the
extra-framework aluminum into framework positions.
DESCRIPTION OF THE INVENTION
[0019] The Applicant has now discovered a process for preparing a
catalyst comprising a mesoporized zeolite showing good catalytic
activity, especially in hydroconversion reactions, due to the
so-called "healing" of the zeolitic structure by a post-synthesis
treatment of a mesoporized material.
[0020] According to a first aspect, a subject of the invention is a
process for preparation of a catalyst comprising a mesoporized
zeolite, including the steps of: [0021] A--preparation of a
protonic mesoporized zeolite, which contains at least one network
of micropores and at least one network of mesopores, and [0022] B--
treatment in a gas or liquid phase containing ammonia or ammonium
ions.
[0023] According to this process, in step B, the partially
destroyed zeolite structure after step A) is restored by
re-inserting the extra-framework aluminum, i.e generally admitted
as being Al atoms in octahedral coordination, into framework
positions, i.e also generally admitted as being Al atoms in
tetrahedral coordination. Besides, the ratio of the octahedral
aluminium to tetrahedral aluminium can be from 0 to 0.5,
especially, from 0 to 0.4 and more particularly, from 0 to 0.3.
These effects lead to improved catalytic activity, especially when
these materials are used in hydroconversion reactions.
[0024] The process according to the invention, especially after
step B), is thus advantageously consisting of re-inserting the
extra-framework aluminum into framework positions of said
catalyst.
[0025] The process allows the preparation of a catalyst comprising
a mesoporized zeolite with healed zeolitic structure, which could
also be named in the present specification as "final mesoporized
zeolite catalyst". In some embodiments, the catalyst as such is
consisting of a mesoporized zeolite with healed zeolitic
structure.
[0026] The final mesoporized zeolite catalyst obtained after step
B) has the following characteristics: [0027] crystallinity of 0 to
100%, preferably from 0 to 98%, for example, from 0 to 95%; higher
compared to the material prepared in step A) [0028] specific
surface area (BET) from 100 to 850 m.sup.2/g, for example, from 150
to 800 m.sup.2/g, [0029] external specific surface area from 20 to
500 m.sup.2/g, for example, from 30 to 400 m.sup.2/g, [0030] total
pore volume from 0.2 to 0.9 ml/g, for example, from 0.25 to 0.6
ml/g, [0031] microporous volume in the range of 0.01 to 0.5 mL/g,
especially, 0.002 to 0.4 mL/g, [0032] mesoporous volume (pores
between 2 and 50 nm) between 0.1 and 0.9 mL/g, especially, between
0.12 and 0.8 mL/g, [0033] amount of octahedrally coordinated Al
lower compared to that in the material prepared in step A) [0034]
atomic Si/Al ratio in the zeolite framework between 7 and 40, for
example, between 8 and 40, [0035] amount of Bronsted acid sites:
from 0.1 to 0.6 mmol NH.sub.3/g, for example, from 0.15 to 0.5 mmol
NH.sub.3/g; higher compared to the material prepared in step
A).
[0036] In some aspects, the zeolite or a composite material
comprising it as starting material used in step A) preferably
presents a framework atomic Si/Al ratio between 10 and 50.
[0037] Advantageously, the starting material is a zeolite of a FAU
framework type and is, in some aspects, a zeolite Y.
[0038] In summary, a zeolite of a certain or predetermined
framework atomic Si/Al ratio has been mesoporized by base treatment
bringing with it a partial destruction of the zeolitic structure
(step A)). Upon the above-described NH.sub.3-treatment or with
ammonium ions (step B)), the zeolitic part of the material has been
healed due to the re-insertion of extra-framework Al into the
framework positions; whereas the mesoporosity remained preserved. A
mesoporized zeolite with healed zeolitic structure has been
prepared. The combination of mesoporosity and healed zeolitic
structure can lead to an optimal combination of selectivity to
middle distillates and high activity in numerous reactions.
[0039] Thus the process according to the invention in particular
includes a treatment of a zeolite, as starting material, having a
predetermined framework atomic Si/Al ratio, in a basic pH medium
(step A)) and a treatment of the protonic mesoporized zeolite
obtained in step A) in a gas or liquid phase containing ammonia or
ammonium ions.
[0040] Step A)
[0041] A protonic mesoporized zeolite is a zeolite having protons
as counter ions.
[0042] Step A) of preparation of the protonic mesoporized zeolite
may include the following steps: [0043] a) suspending a parent
zeolite as starting material or a composite material comprising it
in a basic aqueous solution comprising at least one strong base,
especially NaOH or KOH, and/or an inorganic or organic weak base,
such as sodium carbonate, sodium citrate or a tetraalkyl ammonium
hydroxide, for example, at a concentration ranging from 0.001 to 2
M, at room temperature, with magnetic or mechanical stirring,
[0044] b) neutralizing the medium by addition of at least one acid,
for example, at a concentration ranging from 0.005 to 2 M, at room
temperature, with stirring, [0045] c) separating the zeolite
obtained from the liquid and optionally washing it with a solvent,
especially a polar solvent, for example, water, [0046] d)
optionally drying the washed zeolite, [0047] e) optionally
performing at least one ion exchange treatment of the zeolite from
step c) or of the optionally dried zeolite from step d), [0048] f)
optionally washing the zeolite, [0049] g) calcining the zeolite
obtained, and [0050] h) recovering the zeolite, i.e the protonic
mesoporized zeolite.
[0051] The non limitative step a) includes a treatment of a parent
zeolite by suspension thereof in a basic solution. The parent
zeolite may also be a composite material comprising it, especially
at a content of at least 5% by weight relative to the total weight
of the composite material.
[0052] A composite material is a material containing a certain
fraction of a parent zeolite, but also optionally an amorphous
phase produced during the modification of the parent zeolite and/or
a binder being a metal oxide or a mixture of metal oxides. The
zeolite used during step a) of the process preferably presents a
bulk atomic Si/Al ratio of greater than or equal to 12.
[0053] A zeolite of such atomic framework Si/Al ratio may be also
obtained, for example, after at least one dealumination treatment,
in particular, a partial dealumination treatment, for example, with
at least one acid and/or water vapour. These treatments may lead to
(i) reduction in the acidity of the material, (ii) increase, albeit
slightly, in the mesoporosity of the initial material, which is
theoretically purely microporous. Most particularly, these
treatments correspond to those described in patent U.S. Pat. No.
5,601,798.
[0054] In step a), the basic pH solution/zeolite weight ratio may
range from 4 to 100, or even from 20 to 100, preferably from 5 to
80, especially from 30 to 80, in particular, from 40 to 60, or may
even be about 50.
[0055] The base concentration of the solution in step a) may range
from 0.001 to 2 M, especially, from 0.005 to 1, in particular, from
0.01 to 0.5, or may even be about 0.05 M.
[0056] In step a), the placing in contact with a basic solution may
last from 5 to 120 minutes, especially, from 10 to 60 minutes and
in particular, from 15 to 30 minutes. During this placing in
contact, the suspension may be stirred, especially, by magnetic or
mechanical stirring.
[0057] The neutralization according to step b) may be performed by
contacting with an acid-containing solution, for example, sulphuric
acid under industrial conditions, on a large amount of material.
The neutralization step may likewise be performed in presence of
water. This neutralization is advantageously carried out at room
temperature under magnetic or mechanical stirring.
[0058] The acid-containing solution is comprising at least one
acid, for example, at a concentration ranging from 0.005 to 2 M, at
room temperature, under stirring.
[0059] The purpose of the neutralization is to stop the
desilication process and to prevent the undesired destruction of
the material that can result in extensive loss of crystalline
structure of the zeolite, loss of microporosity and induce a
decrease in the intrinsic activity of the material.
[0060] The process also includes, after the step b), a step c) of
separating the mesoporized zeolite from the neutralized solution by
any known means to obtain a solid mesoporized zeolite, followed by
the washing step.
[0061] The mesoporized zeolite may then be dried (step d)). The
drying step may be performed at a temperature greater than or equal
to 70.degree. C., especially, greater than or equal to 75.degree.
C., or even greater than or equal to 80.degree. C. It may range
from 1 to 36 hours, especially, from 1 to 24 hours and in
particular, from 1 to 15 hours. The drying may be performed in air
or under an inert atmosphere.
[0062] The drying step may last until the weight of the product no
longer changes, in particular, when the difference between the
weight of the product at a time t and the weight of this product
after two hours of heating changes by less than 0.1% by weight
relative to the total weight of the product.
[0063] The step e) may include placing the washed (step c)) or
optionally dried (step d)) zeolite in contact with a solution
containing ammonium ions in order to perform the at least one ion
exchange treatment.
[0064] The ion exchange solution, advantageously comprising a
solution containing ammonium ions, especially NH.sub.4NO.sub.3, and
the mesoporized zeolite weight ratio, may range from 3 to 75,
especially from 3 to 50, in particular, from 3 to 30. The
NH.sub.4NO.sub.3 concentration of the solution of step e) may range
from 0.01 to 0.5 M, especially, from 0.05 to 0.4, in particular,
from 0.1 to 0.3, or may even be about 0.2 M.
[0065] Placing in contact with the solution containing ammonium
ions (step e)) may last from 1 to 24 hours, especially, from 1 to
12 hours, in particular, from 1 to 8 hours. This step may be
performed one to three times.
[0066] Advantageously, step e) can be carried out at room
temperature, therefore, do not require heating.
[0067] For the purposes of the present invention, the term "room
temperature" means a temperature ranging from 10 to 55.degree. C.
and in particular, between 15 and 35.degree. C.
[0068] The washing step f) may in some aspects be optional, and if
so may be carried out with water.
[0069] The calcination step (step g)) may be performed at a
temperature of greater than or equal to 400.degree. C., especially,
greater than or equal to 450.degree. C., or even greater than or
equal to 500.degree. C. The heating may last from 1 to 8 hours, in
particular, from 1 to 6 hours, or even from 1 to 5 hours. The
heating may comprise a temperature rise of 0.5 to 2.degree.
C./minute and especially, 1.degree. C./minute. The heating may be
performed in air or under an inert atmosphere.
[0070] Then, the catalyst essentially consisting of a protonic
mesoporized zeolite is recovered (step h)).
[0071] By implementing step A) of the process a protonic
mesoporized zeolite catalyst can be obtained exhibiting a trimodal
porosity, represented by at least one network of micropores and at
least one network of mesopores, the latter advantageously including
at least one network of small mesopores with a mean diameter of 2
to 5 nm and at least one network of large mesopores with a mean
diameter of 10 to 50 nm, these various networks being
interconnected.
[0072] The protonic mesoporized zeolite of the present invention
thus can have trimodal intracrystalline porosity, i.e. containing
three networks of pores of different mean diameters within each
crystal.
[0073] More specifically, the protonic mesoporized zeolite presents
a micropore volume that is 10%, especially, 20%, in particular,
30%, or even 50% less than the micropore volume of the starting
zeolite.
[0074] The protonic mesoporized zeolite may have a mesopore volume
that is 10%, especially 20%, in particular 30%, or even 55% higher
than the mesopore volume of the starting zeolite. In particular,
the increase in mesopore volume is essentially due to the creation
of small mesopores.
[0075] The protonic mesoporized zeolite may have an atomic bulk
Si/Al ratio of less than or equal to 50, especially, less than or
equal to 40, or even less than or equal to 30, more particularly,
less than or equal to 25, even more particularly, less than or
equal to 23 and optionally, less than or equal to 20.
[0076] The bulk Si/Al atomic ratio may be greater than or equal to
5, especially, greater than or equal to 6, or even greater than or
equal to 7.
[0077] The atomic framework Si/Al ratio may lay between 7 and
40.
[0078] The protonic mesoporized zeolite advantageously has a ratio
of the volume of the small mesopores (Vs) to the volume of the
large mesopores VI, Vs/Vl, of greater than or equal to 1,
especially greater than or equal to 1.20, or even greater than or
equal to 1.60, more particularly, greater than or equal 1.80 and
even more particularly, greater than or equal to 2.
[0079] The protonic mesoporized zeolite has a total mesopore volume
of greater than or equal to 0.20 ml/g, especially greater than or
equal to 0.25 ml/g, in particular, greater than or equal to 0.35
ml/g, or even greater than or equal to 0.40 ml/g.
[0080] The protonic mesoporized zeolite has a micropore volume of
less than or equal to 0.20 ml/g, especially, less than or equal to
0.18 ml/g, in particular, less than or equal to 0.16 ml/g, or even
less than or equal to 0.125 ml/g and more particularly, less than
or equal to 0.10 ml/g.
[0081] The zeolite prepared according to step A) has a total
mesopore volume/micropore volume ratio of greater than or equal to
1, especially, greater than or equal to 1.5, in particular, greater
than or equal to 3, or even greater than or equal to 3.5, more
particularly, greater than or equal to 4, even more particularly,
greater than or equal to 4.5 or even greater than or equal to
5.
[0082] The protonic mesoporized zeolite may have an external
surface area S.sub.ext of greater than or equal to 100 m.sup.2/g,
especially, greater than or equal to 150 m.sup.2/g, in particular,
greater than or equal to 200 m.sup.2/g, or even greater than or
equal to 250 m.sup.2/g and more particularly, greater than or equal
to 300 m.sup.2/g.
[0083] The acid site density, measured by TPD of ammonia (TPD
NH.sub.3), may be less than or equal to 0.5 mmol/g, especially,
less than or equal to 0.48 mmol/g, in particular, less than or
equal to 0.45 mmol/g or even less than or equal to 0.4 mmol/g.
[0084] Optionally, after performing step A) and before performing
step B), a step of treatment with water vapour, preferably at a
temperature ranging from 250 to 450.degree. C. for 1 to 6 hours, is
performed. This so-called "steaming step" may help to
repair/hydrolyse the bonds with aluminium that may have been broken
during the alkaline treatment.
[0085] Optionally, instead or/and after the steaming step, the
material is contacted with an aqueous acid solution of a
concentration between 0.01 and 1 M at room temperature, for 5 to 60
minutes under mechanical or magnetic stirring.
[0086] Step B)
[0087] In step B), the protonic mesoporized material obtained in
step A) is subjected to a treatment in a gas or liquid phase
containing ammonia or ammonium ions.
[0088] The treatment in the gas phase can be carried out by
subjecting the optionally steamed protonic mesoporized zeolite
obtained in step A) to a treatment with a compound able to release
gaseous ammonia (in situ) or ammonium ions. The treatment in a gas
or in a liquid phase containing a source of ammonia and/or ammonium
ions may thus be performed.
[0089] This compound or a mixture of compounds can be pure or
diluted with an inert gas, such as nitrogen, helium or argon. The
volume percentage of the ammonia/ammonium ions-releasing compound
or the ammonia/ammonium ions source can be between 1 and 50 vol %,
especially, between, 3 and 40 vol % and particularly, between 5 and
30 vol %. The treatment of step B) can take place in the
temperature range between 15 and 600.degree. C., preferentially, 20
and 350.degree. C.
[0090] Optionally, the protonic mesoporized and optionally steamed
zeolite, could be dried and then calcined in situ prior to the
treatment, at temperatures up to 650.degree. C. in oxidative
atmosphere, such as oxygen, air, nitrous gases, or/and inert
atmosphere, such as nitrogen, helium or argon.
[0091] The treatment can take place in the temperature range
between 15 and 600.degree. C., especially, between 20 and
350.degree. C., particularly, between 20 and 300.degree. C. The
duration of the treatment can be 30 minutes to 24 hours,
especially, 1 to 5 hours.
[0092] Optionally, a calcination step can be placed before, at
temperatures up to 650.degree. C., preferentially, up to
550.degree. C., with a heating rate of 0.1 to 5.degree. C./min, in
oxidative atmosphere, such as oxygen, air, nitrous gases, or/and
inert atmosphere, such as nitrogen, helium or argon, inert
atmosphere being preferred. The calcination may last from 30
minutes to 12 hours, preferentially, 1 to 5 hours.
[0093] As a source of ammonia, every N-containing molecule that
decomposes to ammonia or forms it can be used. Among them, ammonium
salts, ammonium hydroxide, amines, nitrates, nitrites, nitride
ligands, carbamides, nitrides, cyanamides, carbamates, amides,
carbodiimides, (poly)aminoacids, (poly)iminoacids, (poly)aminoacid
salts, (poly)imino acid salts, (poly)amino carboxylates,
(poly)imino carboxylates or their mixture.
[0094] The treatment in the liquid phase can be carried out by
subjecting the optionally steamed protonic mesoporized zeolite
obtained in step A) to a treatment in an aqueous solution
containing a compound able to dissociate to ammonium ions or to
form those. This compound or a mixture of compounds can be for
example, among them, ammonium salts, ammonium hydroxide, amines,
nitrates, nitrites, nitride ligands, carbamides, nitrides,
cyanamides, carbamates, amides, carbodiimides, (poly)aminoacids,
(poly)iminoacids, (poly)aminoacid salts, (poly)imino acid salts,
(poly)amino carboxylates, (poly)imino carboxylates or their
mixture. The weight percentage of the ammonium-releasing compound
can be between 1 and 80 wt %, especially, between, 3 and 70 wt %
and particularly, between 5 and 60 wt %. The treatment can take
place in the temperature range between 10 and 150.degree. C.,
preferentially, 15 and 120.degree. C., most likely, between 20 and
100.degree. C. The duration of the treatment can be 10 minutes to
24 hours, especially, 30 minutes to 7 hours. The treatment can be
carried out several times, one to three times, under mechanical or
magnetic stirring, optionally under reflux.
[0095] Preferably, in the treatment in the liquid phase a solvent
may optionally be used, and during the treatment in the gas phase a
pure compound or a compound diluted with an inert gas may be
used.
[0096] Optionally, the modified zeolite could be dried and then
calcined in situ prior to the treatment, at temperatures up to
650.degree. C. with a heating rate of 0.1 to 5.degree. C./min, in
oxidative atmosphere, such as oxygen, air, nitrous gases, or/and
inert atmosphere, such as nitrogen, helium or argon.
[0097] The final mesoporized zeolite catalyst of step B) has the
following characteristics: [0098] crystallinity of 0 to 100%,
preferably from 0 to 98%, for example, from 0 to 95%; higher
compared to the material prepared in step A), [0099] specific
surface area (BET) from 100 to 850 m.sup.2/g, for example, from 150
to 800 m.sup.2/g, [0100] external specific surface area from 20 to
500 m.sup.2/g, for example, from 30 to 400 m.sup.2/g, [0101] total
pore volume from 0.2 to 0.9 ml/g, for example, from 0.25 to 0.6
ml/g, [0102] microporous volume in the range of 0.01 to 0.5 mL/g,
especially, 0.02 to 0.4 mL/g, [0103] mesoporous volume (pores
between 2 and 50 nm) between 0.1 and 0.9 mL/g, especially, between
0.12 and 0.8 mL/g, [0104] amount of octahedrally coordinated Al
lower compared to that in the material prepared in step A), [0105]
atomic Si/Al ratio in the zeolite framework between 7 and 40, for
example, between 8 and 40, [0106] amount of Bronsted acid sites:
from 0.1 to 0.6 mmol NH.sub.3/g, for example, from 0.15 to 0.5 mmol
NH.sub.3/g; higher compared to the material prepared in step
A).
[0107] The final mesoporized zeolite catalyst, thus containing at
least one network of micropores and at least one network of
mesopores, exhibits an atomic framework Si/Al ratio of greater than
or equal to 2.3, especially, greater than or equal to 3, more
particularly, greater than or equal to 6, advantageously of between
7 and 40, for example, between 8 and 40. Said final mesoporized
zeolite catalyst is very advantageously a hydroconversion
catalyst.
[0108] The final mesoporized zeolite catalyst contains less
extra-framework aluminum than the zeolite prepared during the step
A), i.e the protonic mesoporized zeolite or a mesoporized zeolite
with no healed zeolitic structure. Typically the content being
reduced by at least 5%, advantageously, by at least 10%, more
preferably, by at least 20%, in particular, the extra-framework
aluminum content being below 5%, whereas the extra-framework
aluminum is represented by octahedrally coordinated species and is
characterized by the peak around 0 ppm in the .sup.27Al MAS NMR
spectrum. For the sample prepared during step B), the ratio of the
octahedral aluminum to tetrahedral can be from 0 to 0.5, especially
from 0 to 0.4 and more particularly, from 0 to 0.3.
[0109] The final mesoporized zeolite prepared during step B)
advantageously has a volume of micropores in the range of or 0.01
to 0.5 mL/g, especially, 0.02 to 0.4 mL/g.
[0110] The mesopore volume (pores between 2 and 50 nm) lays between
or 0.1 and 0.9 mL/g, especially, between 0.12 and 0.8 mL/g.
[0111] The process may advantageously include an extrusion step
and/or a modification step of the final mesoporized zeolite
catalyst (step B)) or of the protonic mesoporized zeolite with
metals (step A)).
[0112] The obtained modified zeolite may be extruded before or
after step B) and modified with metals according to known methods,
preferably by impregnation. The metals are advantageously catalytic
metals preferably chosen from compounds of group VIII, group VIB
and mixture thereof. The previous step(s) may be followed by a
calcination step. Group VIB corresponds to group 6 of IUPAC
periodic table of the elements (version of Jun. 22, 2007) and
comprises Cr, Mo and W. Group VIII (VIIIB) corresponds to groups 8,
9 and 10 of IUPAC periodic table of the elements (version of Jun.
22, 2007) and comprises Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt.
[0113] During the extrusion, the binder(s) used may be chosen from
the group consisting of alumina, silica, titania, silica-alumina,
magnesia and mixtures of one or more of these compounds.
[0114] The impregnation may be performed by incipient wetness
impregnation or ion exchange. Typically, the active metal precursor
is dissolved in an aqueous or organic solution. The solution thus
obtained is then added to the modified zeolite, the volume of the
solution added being identical or higher than the pore volume of
the modified zeolite.
[0115] The incipient wetness impregnation may be performed by using
various solvents, preferably water, at temperatures from 10 to
100.degree. C.
[0116] As an option, the introduction of the catalytic metal(s) may
be performed by ion exchange, generally by known methods in the
art. However, this specific impregnation method is the preferred
implementation owing to its easy implementation and in some
instances giving good sought effects.
[0117] Among the catalytic metals, platinum, palladium, nickel,
cobalt, tungsten or molybdenum, but also other transition metals,
can be used, provided they are soluble in above-mentioned
medium.
[0118] Advantageously, the catalyst contains from 0.1% to 10% by
weight of a metal from group VIII, for example, nickel and/or
cobalt and/or platinum, and from 1% to 25% by weight of a metal
from group VIB, for example, molybdenum.
[0119] The extrusion step and modification step with catalytic
metals is mainly applied after step B), however, it can be also
applied after step A) and before the step B), as previously
mentioned.
[0120] According to some embodiments, the extrusion step is applied
after the step A) using the protonic mesoporized zeolite and before
step B), followed by the step B) and then by a subsequent
modification step with metals, said metals being chosen from
compounds of group VIII, from group VIB and mixture thereof,
generally followed by a calcination step. The modification step is
preferably an impregnation step, as previously mentioned.
[0121] Another aspect of the invention concerns a process for the
hydroconversion of hydrocarbon feedstock, for example,
hydrocracking or hydroisomerization, in which the feedstock to be
treated is placed in contact with a catalyst according to the
invention, for example, prepared according to the process of the
invention.
[0122] The hydrocarbon feedstock is advantageously chosen from the
group of light cycle oil, atmospheric distillates, vacuum
distillates such as vacuum gasoil, feeds from aromatic extraction
units, from solvent dewaxing of base lubricating oils, distillates
derived from processes of desulphurisation, deasphalted oils,
vegetable or animal oils, oils issued from algae or from bacteria,
alone or in mixture. This feedstock may also include squalane.
[0123] Particularly, another aspect of the invention concerns a use
of the catalyst obtained according to this invention in a
hydrocracking process.
[0124] Characterization Methods
[0125] The methods used to perform the measurements of the various
characteristics are generally the standard techniques. More
particularly, the following techniques were used in the context of
this invention: [0126] i) the chemical composition, in particular,
the bulk Si/Al atomic ratio and the Pt content, was determined by
X-ray fluorescence spectroscopy; [0127] ii) the structure of the
zeolite was defined by X-ray diffraction (XRD). XRD was conducted
on a Bruker D8 Discover diffractometer in the range between 5 to
70.degree. with a Cu K.sub..alpha.1 radiation using a step-size of
0.02.degree. and time/step of 1 s. The relative crystallinity of
the samples was determined by background subtraction method; [0128]
iii) the nitrogen adsorption and desorption measurements were
performed at the temperature of liquid nitrogen on a Micromeritics
Tristar 3000 machine. Before each measurement, the samples were
degassed under nitrogen at 300.degree. C. for 840 minutes. The
textural properties, defined by the external surface area
(S.sub.ext), the micropore volume (V.sub.micro) and the mesopore
volume (V.sub.meso), were identified by volumetry with nitrogen
using adsorption isotherms recorded at 77 K by applying the
state-of-the-art methods [Barett, E. P.; Joyner, L. G.; Halenda, P.
P. J. Am. Chem. Soc. 1951, 73, 373-380. Rouquerol, F.; Rouquerol,
J.; Sing, K. Adsorption by powders and porous solids; Academic
Press: San Diego, 1999]. The BET method [S. Brunauer, P. H. Emmett
and E. Teller, J. Am. Chem. Soc., 1938, 60, 309] was used to
calculate the specific surface area. The external specific surface
area and the specific pore volume were determined by the t-plot
method, an empirical semi-quantitative method based on the
comparison of the isotherm adsorption data of a porous sample and a
non-porous sample of identical chemical composition and surface
nature [K. S. W. Sing, Chem. and Ind., (1968) 1520]; the
statistical thickness was calculated by means of the Harkins-Jura
formula. The t-plot method is based on the comparison of the
isotherm adsorption data for a porous sample and for a non-porous
sample of identical chemical composition and surface nature;
[0129] iv) the .sup.27Al and .sup.29Si MAS NMR spectra were
acquired on a 500 MHz Bruker Avance spectrometer A500 equipped with
an MAS probe-head of 4 mm. The rotation speed was 15000 Hz. The
coordination of the Al and Si species was determined from the
spectra. The .sup.29Si MAS NMR spectra were deconvoluted in order
to calculate the atomic Si/Al ratio in the framework of the
zeolite; [0130] v) the acidity of the catalysts was established by
programmed thermo-desorption of ammonia (TPD NH.sub.3) between 100
and 650.degree. C. [Niwa, M.; Iwamoto, M.; Segawa, K. B. Chem. Soc.
Jpn. 1986, 59] by monitoring the desorbed ammonia by conductivity;
[0131] vi) the shape and the size of the crystals as well as the
porosity within particular crystals were characterized by
transmission electron microscopy and scanning electron
microscopy.
DESCRIPTION OF THE FIGURES
[0132] The invention is now described with reference to the
attached non-limiting drawings, in which:
[0133] FIG. 1 represents the X-ray diffractograms of the
Pt-exchanged zeolite Y (HY30, CBV760, Zeolyst Int.), of the
mesoporized zeolite Y before steaming (HYA), the mesoporized
zeolite Y after steaming (HYA-st), the ammonia-treated non-steamed
(HYA-NH3) and ammonia-treated steamed (HYA-st-NH3) samples
respectively.
[0134] FIG. 2 shows the pore size distribution for the Pt-exchanged
zeolite Y (HY30, CBV760, Zeolyst Int.), of the mesoporized zeolite
Y before steaming (HYA), the mesoporized zeolite Y after steaming
(HYA-st), the ammonia-treated non-steamed (HYA-NH3) and
ammonia-treated steamed (HYA-st-NH3) samples respectively.
[0135] FIG. 3 shows the .sup.27Al MAS NMR spectra of the
Pt-exchanged zeolite Y (HY30, CBV760, Zeolyst Int.), of the
mesoporized zeolite Y before steaming (HYA), the mesoporized
zeolite Y after steaming (HYA-st), the ammonia-treated non-steamed
(HYA-NH3) and ammonia-treated steamed (HYA-st-NH3) samples
respectively.
[0136] FIG. 4 shows the .sup.29Si MAS NMR spectra of the
Pt-exchanged zeolite Y (HY30, CBV760, Zeolyst Int.), of the
mesoporized zeolite Y before steaming (HYA), the mesoporized
zeolite Y after steaming (HYA-st), the ammonia-treated non-steamed
(HYA-NH3) and ammonia-treated steamed (HYA-st-NH3) samples
respectively.
EXAMPLES
[0137] The zeolite Y (CBV760, Zeolyst Int.) is referred to as
HY30.
[0138] The characteristics of HY30 are given in Table 2 and
graphically represented in FIGS. 1 to 5.
Example 1: Preparation of a Mesoporized Zeolite Y (HYA) and its
Steaming (HYA-St)
[0139] The compound HY30 is subjected to the following alkaline
treatment: [0140] HY30 (200 g) is placed in contact with an aqueous
0.05 M NaOH solution (2500 ml) for 15 minutes at room temperature
and under stirring, [0141] the resulting product is filtered off
and washed with water, [0142] the filtered product is dried for 12
hours at 80.degree. C., [0143] aqueous 0.20 M NH.sub.4NO.sub.3
solution (2500 ml) is added to the dry product, and the whole is
left for 5 hours at room temperature under stirring. This
manipulation is performed trice. [0144] the product obtained is
washed with water, [0145] the product is then calcined at
500.degree. C. for 4 hours (temperature gradient of 1.degree.
C./minute) in a stream of air, and then [0146] the HYA is
recovered.
[0147] HYA-st is prepared by steaming HYA at 300.degree. C. for 4
hours (temperature gradient 5.degree. C./min).
[0148] The characteristics of the samples are given in Table 2,
graphically represented in FIGS. 1-5 and discussed in Examples 3
and 4.
Example 2: Treatment of a Mesoporized Zeolite Y Before and after
Steaming (HYA/HYA-St) with Gaseous NH.sub.3
(HYA-NH3/HYA-St-NH3)
[0149] HYA and HYA-st are respectively subjected to the following
treatment: [0150] The sample (2 g) is placed in a U-formed glass
tube and calcined at 550.degree. C. (1.degree. C./min) for 6 hours
in a flow of He, [0151] Then, the sample is cooled down to
150.degree. C. in a flow of He and stabilized for 30 minutes,
[0152] The gas is switched from pure He to 10 vol % NH.sub.3 in He,
[0153] The samples are cooled to the room temperature and
stabilized for 30 minutes in a flow of 10 vol % NH.sub.3 in He,
[0154] HYA-NH.sub.3 and HYA-st-NH.sub.3 are respectively
recovered.
[0155] The characteristics of the samples are given in Tables 1 and
2, graphically represented in FIGS. 1-5 and discussed in Examples 3
and 4.
Example 3: Characterization of the Compounds HYA-St and HYA-St-NH3
Before Impregnation with Pt
[0156] Table 1 summarizes several characteristics of the HYA-st and
HYA-st-NH3. The framework atomic Si/Al is decreasing after
NH.sub.3-treatment, pointing to the re-insertion of some
extra-framework Al into the framework positions. The distribution
of different Al species shows that mostly pentahedral Al is
transformed to tetrahedral framework Al upon NH.sub.3-treatment.
The re-insertion of Al into the framework positions can be
associated with the healing of the structure of zeolite Y.
[0157] In summary, a dealuminated zeolite Y has been further
mesoporized by base treatment bringing with it a partial
destruction of the zeolitic structure. Upon the above-described
NH.sub.3-treatment, the zeolitic part of the material has been
healed due to the re-insertion of extra-framework Al into the
framework positions; whereas the mesoporosity remained preserved. A
mesoporized zeolite Y with healed zeolitic structure has been
prepared. The combination of mesoporosity and healed zeolitic
structure can lead to an optimal combination of selectivity to
middle distillates and high activity in numerous reactions.
[0158] Table 1. Summary of the characterization results of HYA-st
and HYA-st-NH3
TABLE-US-00001 TABLE 1 Summary of the characterization results of
HYA-st and HYA-st-NH3 Sample HYA-st HYA-st-NH3 Si/Al frame.sup.a
21.87 14.62 Al(tetrahedral).sup.b % 46.7 89 Al(pentahedral).sup.b %
48.7 2.9 Al(octahedral).sup.b % 4.6 8.1 .sup.aSi/Al atomic in the
framework of the zeolite; .sup.bfrom the deconvolution of .sup.27Al
MAS NMR spectra
Example 4: Characterization of the Compounds HY30, HYA, HYA-St,
HYA-NH3 and HYA-St-NH3 Ion-Exchanged with Pt for Further Catalytic
Testing
[0159] X-Ray Diffraction
[0160] FIG. 1 shows the X-ray diffractograms of the Pt-exchanged
zeolite Y
[0161] (HY30, CBV760, Zeolyst Int.), of the mesoporized zeolite Y
before steaming (HYA), the mesoporized zeolite Y after steaming
(HYA-st), the ammonia-treated non-steamed (HYA-NH3) and
ammonia-treated steamed (HYA-st-NH3) samples respectively.
[0162] HYA shows very weak reflections around 6.1, 9.97, 11.69, and
15.39 degrees 28, corresponding to the reflections of the FAU
structure. The reflections are weak and broad, probably, due to the
small crystal size of the sample. There are no visible reflections
in the diffractogram of HYA-st. After treatment with gaseous
ammonia, the FAU-typical reflections appear in the diffractograms
of HYA-NH3 and HYA-st-NH3, indicating the healing of the long-range
zeolite structure.
[0163] The crystallinity increases for the NH.sub.3-treated samples
(Table 2).
TABLE-US-00002 TABLE 2 Summary of the characterization results of
Pt-modified HY30, HYA, HYA-st, HYA-NH3 and HYA-st-NH3 HYA- HYA-st-
Sample HY30 HYA HYA-st NH3 NH3 Crystallinity % 8 0 0 21 10 Si/Al
bulk .sup. n.d..sup.g n.d. n.d. n.d. n.d. Si/Al frame.sup.a 12.4
10.9 10.5 9.2 8.3 S.sub.BET.sup.b m.sup.2/g 296 299 285 467 385
S.sub.ext.sup.c m.sup.2/g 296 299 285 325 310 V.sub.tot.sup.d ml/g
0.36 0.38 0.38 0.44 0.41 V.sub.micr.sup.e ml/g 0.01 0.01 0.01 0.07
0.04 V.sub.meso.sup.f ml/g 0.22 0.23 0.23 0.32 0.27 TPD-NH.sub.3
mmol/g 0.36 0.33 0.38 0.46 0.38 Pt content wt % n.d. n.d. n.d. n.d.
n.d. .sup.aSi/Al in the framework of the zeolite; .sup.bBET surface
area; .sup.cexternal surface area; .sup.dtotal pore volume;
.sup.emicroporous volume; .sup.fmesoporous volume; .sup.gnot
determined.
[0164] Nitrogen Sorption
[0165] The BET surface areas of the samples HY30, HYA and HYA-st
are laying between 285 and 300 m.sup.2/g. After the
NH.sub.3-treatment, the BET surface areas of the corresponding
samples are increasing, resulting in 467 m.sup.2/g for HYA-NH3 and
385 m.sup.2/g for HYA-st-NH3. For the samples before the
ammonia-treatment, the BET surface area is corresponding to the
external surface area, pointing to the absence of micropores in the
samples. After the ammonia-treatment, the microporous volume
increases from 0 to 0.07 mL/g for HYA-NH3 and 0.04 mL/g for
HYA-st-NH3.
[0166] The mesoporous volume as well as the total pore volume is
increasing after the ammonia-treatment, reaching 0.32 mL/g for
HYA-NH3. FIG. 2 shows the pore size distribution of HYA, HYA-st,
HYA-NH3 and HYA-st-NH3. All catalysts show two maxima in the
mesopore region. HYA and HYA-st have maxima around 3 nm and 19 nm,
whereas the ammonia-treated samples around 3.1 nm and 16 nm.
Therefore, they have at least trimodal porosity taking into account
the presence of micropores in these samples.
[0167] Elemental Analysis
[0168] .sup.27Al MAS NMR Spectroscopy
[0169] FIG. 3 shows the .sup.27Al MAS NMR spectra of the
Pt-exchanged HY30, of the mesoporized zeolite Y before steaming
(HYA), the mesoporized zeolite Y after steaming (HYA-st), the
ammonia-treated non-steamed (HYA-NH3) and ammonia-treated steamed
(HYA-st-NH3) samples respectively.
[0170] All samples show an intense peak at about 55 ppm,
corresponding to the tetrahedrally coordinated Al species. HY30,
HYA, and HYA-st contain a small amount of octahedrally coordinated
Al, represented by the peak at about 0 ppm. After the treatment
with ammonia, the octahedrally coordinated Al disappears, whereas
the peaks at 55 ppm become more pronounced. As no washing steps
were carried out during the treatment with ammonia, we assume that
the octahedrally and pentahedrally coordinated Al was reinserted
into the framework positions of the zeolite upon treatment with
ammonia.
[0171] .sup.29Si MAS NMR Spectroscopy
[0172] FIG. 4 shows the .sup.29Si MAS NMR spectra of the
Pt-exchanged HY30, of the mesoporized zeolite Y before steaming
(HYA), the mesoporized zeolite Y after steaming (HYA-st), the
ammonia-treated non-steamed (HYA-NH3) and ammonia-treated steamed
(HYA-st-NH3) samples respectively. All spectra show overlapped
peaks between -115 and -90 ppm, corresponding to the Si coordinated
to one to two Al atoms. The spectra of HY30, HYA and HYA-st are
similar, whereas after the treatment with ammonia, the peaks at
higher ppm-values increase. This indicates the increase of the
relative amount of Si(1Al) and probably also Si(2Al) species
pointing out the reconstruction of the zeolitic structure.
[0173] Temperature-Programmed Desorption of Ammonia
(TPD-NH.sub.3).
[0174] HY30 showed 0.36 mmol NH.sub.3/g. After the desilication
(HYA), the amount of acid sites decreased to 0.33 mmol NH.sub.3/g.
The steaming caused a slight increase in the overall acidity to
0.38 mmol NH.sub.3/g. By treating HYA and HYA-st in the presence of
gaseous ammonia, the overall acidity of HYA increased to 0.46 and
that of HYA-st remained at 0.38 mmol NH.sub.3/g.
Transmission and Scanning Electron Microscopy
Example 5: Catalysis--Hydrocracking of Squalane
[0175] The samples HY30, HYA, HYA-st, HYA-NH3 and HYA-st-NH3
containing 0.5 wt % Pt were catalytically tested in hydrocracking
of squalane (Alfa Aesar, 98.8%). The tests were performed using
plug-flow reactors at following operating conditions:
H.sub.2 pressure: 20 barg
Temperature: 180-300.degree. C.
[0176] WHSV: 3 h.sup.-1 H.sub.2/squalane ratio: 4 mol/mol.
[0177] The tests were performed using 1 mL of catalyst (sieved to
120-160 .mu.m), activated at 450.degree. C. (1.degree. C./min) for
4 h in a flow of hydrogen.
[0178] FIG. 5 shows the plots of conversion vs. temperature for all
samples.
[0179] FIG. 6 shows the product distribution plots (weight
percentage vs. C-cuts) at 75% conversion based on the data obtained
by simulated distillation of the products obtained at different
temperatures.
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