Zeolite Chemistry and Catalysis, Proceedings of an International Symposium

504 Pages·1991·20.847 MB·iii-xiv, 1-514\504

by  P.A. Jacobs, N.I. Jaeger, L. Kubelková and B. Wichterlov´ (Eds.)

Studies in Surface Science and Catalysis
Advisory Editors: B. Delmon and J.T. Yates
Vol. 69
ZEOLITE CHEMISTRY
AND CATALYSIS
Proceedings of an International Symposium, Prague, Czechoslovakia,
September 8-1 3,1991
Editors
P.A. Jacobs
Laboratorium voor Oppervlaktechemie, Katholieke Universiteit Leuven,
Kardinaal Mercierlaan 92, 8-3030 Leuven (Heverlee), Belgium
N.I. Jaeger
Universitat Bremen, Forschungsgruppe Ange wandte Katalyse, Postfach
330440, D-2800 Bremen, Germany
and
L. Kubelkova and B. Wichterlova
J. He yrovskp Institute of Physical Chemistry and Electrochemistry,
Czechoslovak Academy of Sciences, DolejSkova 3, 182 23 Prague 8,
Czechoslovakia
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XI
Preface
The International Symposium entitled "ZEOLITE CHEMISTRY AND CATALYSIS",
8 13,
held in Prague from September to 1991 and elected by the International
Zeolite Association as a local IZA Symposium, is one of a series of European
Symposia which has been organized during the past decade.
As the field of zeolite science is continually growing, each of the
previous locally organized European Zeolite Symposia (Szeged, Villeurbanne,
Bremen, Prague, Siofok, Nieuwpoort, Wurzburg, Leipzig) has focussed on a
particular area in zeolite science and technology. The present Symposium
on
emphasizes the effect of modifying components the structure and reactivity
of
molecular sieves. The plenary lectures and contributed papers concentrate
of
on the problem isomorphous substitution in a zeolitic framework; on the
occlusion and the structure of metal, metal oxide, and metal sulfide clusters
and complexes in the intracrystalline void volume of molecular sieves and
zeolites as well as in the interlaminar space of layered compounds.
Attention has been paid to synthesis, structural characterization and
the mobility of charged encapsulates in such phases or their mixtures.
Moreover, not only has the impact of such modifications on catalysis been
examined, but also the use of such materials as active components in photo or
chemical sensors.
New developments are to be expected from the recent growth of knowledge
in traditional areas of zeolite applications and from the recent progress
which has been made with such systems in material science. The use of zeolitic
materials as hosts for specific chemical entities and their application in
SUPRAMOLECULAR chemistry and catalysis looks particularly promising.
XI1
We expect that the Prague 1991 Symposium and its Proceedings will become
a milestone in this evolution and will stimulate not only the use of molecular
sieves in new research areas but also in applications involving new and
sophisticated experimental and theoretical methods. The Peer review system to
which all the contributed papers were subjected, guaranteed the high quality
of
the zeolite science papers in the present volume.
A.
Prague, June 1991 Peter Jacobs
Nils I. Jaeger
Ludmila Kubelkova
BlankaWichterlova
Acknowledgements
The Organizing Committee of the International Symposium on "Zeolite
Chemistry and Catalysis" held in Prague from September 8 to 13, 1991 highly
appreciated the efforts of all the participants who contributed to the
Scientific Program of the Symposium and presented their results in plenary
lectures, contributed papers and in recent research reports. We thank all the
organizations and companies which sponsored this Symposium, thereby enabling,
especially, our younger colleagues to participate.
of
The work the Scientific Committee in accomplishing the difficult task
of selecting the contributed papers deserves a special mention. The Editors
would also like to thank the authors for their careful preparation of the
camera ready manuscripts and the reviewers who conscientiously evaluatedthese
papers in short time.
XI1
We expect that the Prague 1991 Symposium and its Proceedings will become
a milestone in this evolution and will stimulate not only the use of molecular
sieves in new research areas but also in applications involving new and
sophisticated experimental and theoretical methods. The Peer review system to
which all the contributed papers were subjected, guaranteed the high quality
of
the zeolite science papers in the present volume.
A.
Prague, June 1991 Peter Jacobs
Nils I. Jaeger
Ludmila Kubelkova
BlankaWichterlova
Acknowledgements
The Organizing Committee of the International Symposium on "Zeolite
Chemistry and Catalysis" held in Prague from September 8 to 13, 1991 highly
appreciated the efforts of all the participants who contributed to the
Scientific Program of the Symposium and presented their results in plenary
lectures, contributed papers and in recent research reports. We thank all the
organizations and companies which sponsored this Symposium, thereby enabling,
especially, our younger colleagues to participate.
of
The work the Scientific Committee in accomplishing the difficult task
of selecting the contributed papers deserves a special mention. The Editors
would also like to thank the authors for their careful preparation of the
camera ready manuscripts and the reviewers who conscientiously evaluatedthese
papers in short time.
XIII
Organizing Committee
R. Zahradnik (chairman)
V. BosaEek J. Kapieka Z. Tvarfiikova
J. Cejka J. Koubek B, Wichterlovh
K. Habersberger J. Krtil N. iilkova
I. Jirka L. Kubelkova
JirPl
P. J. Novakova
Scientific Committee
H. van Bekkum (Delft University, The Netherlands)
H.K. Beyer (Academy of Sciences, Budapest, Hungary)
A.C. Corma (Institute of Chemical Technology, Valencia, Spain)
D. Barthomeuf (University P.& M. Curie, Paris, France)
J. Dwyer (UMIST, Manchester, Great Britain)
G.J.
Hutchings (Liverpool University, Great Britain)
P.A . Jacobs (Catholic University, Leuven, Belgium)
N.I. Jaeger (Bremen University, Germany)
H G. Karge (Fritz-Haber-Institute, Berlin, Germany)
A. Kiss (Degussa AG, Hanau, Germany)
J.A . Lercher (Technical University, Vienna, Austria)
W. Mortier (Exxon Chemical Holland B.V.,R otterdam, The Netherlands)
G. Schulz-Ekloff (Bremen University, Germany)
A. A. Slinkin (Academy of Sciences, Moscow, USSR)
D. E. W. Vaughan (Exxon Research and Engineering Co. , Annandale, USA)
J.C. Vedrine (Research Institute for Catalysis, Vil eurbanne, France
J. Vblter (Central Institute of Physical Chemistry, Berlin, Germany)
XIV
Financial support
BP International Ltd., Sunbury on Thames, Great Britain
Chemical Works, Litvinov, CSFR
Czechoslovak Academy of Sciences, Prague, CSFR
Degussa, AG, Frankfurt, FRG
Dow Benelux, Terneuzen, The Netherlands
A.
Eniricerche S.p . Milano, Italy
Exxon Chemical Holland B. V., Rotterdam, The Netherlands
Grace GmbH, Worms, FRG
International Zeolite Association (IZA)
Sudchemie AG, Munich, FRG
P.A. Jacobs et al. (Editors), Zeolite Chemistry and Catalysis 1
1991 Elsevier Science Publishers B.V., Amsterdam
eo,
J Dqer, J Dew-, K Karhn, S Holmes, A F A A Garforth and
D J Rawlence (a)
UMIST Chemistry Saclrville Street, MANcHEsTER M60 lQD, UK
(a)Crosfield Catalysts, 4 Liverpool Road, WARRINGION WA5 lAB,
cfieshire, UK
secondary
zeolites of type Y are prepared by either primary or
synthesis. S t r u a e s include zeolite Y in both the cubic and
hexagonal forms, SAFC-37 and faujasitic frameworks Containing Ga or Zn.
These materials are characterised using solid state NMR, X-ray powder
diffraction, infrared spectroscopy, surface analysis and sorption.
are
Catalysts then evaluated for the conversion of n-hexane,
Resultsare
cyclohexane andgas-oil. interpretedin terms of the
the
effectiveness of catalytic sites in alkane activation and in effect
of both density and distribution of active sites.
lTmamaTm
The extensive use of zeolite Y as an acid catalyst for hydrccarbn
impad
conversion has had a mjor on the petroleum refining industry.
Zeolite Y has the faujasite fmwork structure (1) consisting of
units (p tetrahedra,
SOddLite cages) linked through rings of six via
OF-, to generate layers of scdalite units linked by double-six
are
r T s (hexagonal prisms). The layers also linked by hexagonal
prisms in an ABc seqgence to generate a tetrahdral array of scdalite
units symmetry space
having cubic and the same group (Fd3m) as diamond.
In fact the structure of zeolite Y is readily derived from that of
carbon scdalite
diamond if atcnns are replaced by units and C-C bonds by
double-six rings. This arrangement of sodalite uni-t s generates wide
pores of 12 linked tetrahedra, with free diameter 7 8A, which provide
- A diameter.
entrances into larger supercages of 11 12 The supercages
and linked tetrahedrally viathe 12 rings to form an openthree
dimensional pore system (Fig 1).
An analogue of zeolite Y, sconetimes called hexagonal Y, has also been
structm
synthesised recently (2). In this layers of linked scdalite
sequence ABAB, mtatirg
units are linked in the by every second layer,
syrmnetry structures
to produce hexagonal (Fig 1). These framework
end members
represent with other intermediate structures for example
ZSM-20 (2) represented by varying stacking sequences. In the hexagonal
framework there are five, 12-ring openings in each supercage, two of
which (in the 001 direction) are planar, the other three being
elliptical (Fig 1).
2
rxlring the last decade or so heteratom have been intrcduced into the
faujasitic framework, and a phosphate-based material (SARI - 37) has
also been synthesised with the faujasitic framework (3).
?Lpically, zeolite Y is synthesis&, in aqueous alkaline media, with a
framework ccanposition Si/Al I 3 and in order to enhance
thermal/hydrothennal stability to modify catdlytic function, post-
and
synthesis modifications employed. Typical post-synthesis procedures
are
for siliceous zeolite Y involve hydrothermal treatment (4) or
dealmination by chemical methcds. chemical dealunination can utilise
agents such as EDTA (5) which remove alminimwith very
ccanplexing
replacement of silicon in the site, or they utilise
limited vacated
secondary synthesis prooeCtures in which a second source of silicon is
available for "healingll framaJork vacancies prcduced by extraction of
aluminium. Secondary synthesis involve gas/solid reactions for
may
example reaction zeolites with Sic14 (6) or solid/ solution reactions
of
for exanple reaction of zeolites and aqueous (MIq)2SiF6 (7). of
Both
approaches canbe hqmrate heteroatms into zeolite
these usedto
frameworks (8) (9).
The present lecture describes recent work by the authors, on siliceous
forms of zeolite Y (cubic and hexagonal) , SAFO-37, and gallated Y
zeolites. The materials used well-characterised evaluated
are and are
catalytically the mnversion of n-hexane, cyclohexene gas-oil
using and
to on (i) site activity (ii) site density (iii) site
camment
distribution (iv) the role of gallium in catalysts.
and FCC
cl~emically stabilisedy zeolites (CSY) were prepared by a
reacting
slurry of W Y (Si/Al = 2.5) at 70(cid:176)C and buffered at pH = 6.5 with an
aqueous solution of (MIq) 2Ss6 (9). Heteroatm Y zeolites were prepared
in a similar way but using fluorides of gallium zinc in place of
and
silicon hexafluoride (12). A semi-batch reactor was used and in all
cases products were washed free of fluoride.
siliceous zeolite Ywas synthesiseddirectly inbothcubic
also and
forms (2) using the templated aqueous fluoride
hexagonal system
and the intergrowth zm-20 (10) was dlso synthesis&. SAFO-37 was
synthesised using published procedures (3).
olaraderisation
procedures
The XRD data were obtained usin-g an XIlS 2000 SCINTAG diffractcm&er (Cu
radiation) over a range of 2 60" 2 Theta. The unit cell dimensions
Kcr
determined using silicon as fo1lmh-g AS'IM
were internal standard
methcds. Nitrcgen sorption isothm surface were
and areas
3
~lgure1 , Cubic faujarite framevork Hexagonal faqarih framework
770‘ J I ‘243
10 20 30 0 10 20 30
NUflBER OF FRAflEWDRK ALUMINIUM SUBSTITUTED BY m
Figure 2. Substitution of m (m: Si,Ga.Zn) intu the faujasitic framework
a Changes in frequency of symmetric stretch IIR)
b Changes in unit cell parameters (XRDI
A FLUENCE pA mrn Icrn’l ‘
158 316 L13 631 790 941 11001260
$161 i82
.
Depth profiling of faujasitic zeolites
Figure 3. A 0CS-Y prepared by reaction of B [Ga/AIIY2 prepared by
NH,-Y and INHI, SiF, fluorogallate
ACUB-Y prepared using crown ether
template
NaY ex crusfield catalysts