synthesis of high-silica aluminosilicate zeolites

SYNTHESIS OF HIGH-SILICA ALUMINOSILICATE ZEOLITES... Synthesis of high-silica mordenite 12 PART II HIGH-SILICA ZEOLITES WITH SOLVED STRUCTURE-TYPE CHAPTER I SYNTHESIS OF ZSM-5 ZEOLITES I

SYNTHESIS OF HIGH-SILICA ALUMINOSILICATE ZEOLITES

Advisory Editors: B Delman and J.T Yates

Vol 33

SYNTHESIS OF HIGH-SILICA ALUMINOSILICATE

ZEOLITES

Peter A Jacobs and Johan A Martens

Leboretorium voor Oppervlektecnemie, Katholieke Universiteit Leuven,

P.O Box 211, 1000 AE Amsterdam, The Netherlands

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4 Synthesis of high-silica ZSM-6 with TMA 11

5 Synthesis of high-silica mordenite 12

PART II HIGH-SILICA ZEOLITES WITH SOLVED STRUCTURE-TYPE

CHAPTER I SYNTHESIS OF ZSM-5 ZEOLITES IN THE PRESENCE OF

TETRAPROPYLAMMONIUM IONS

* Introduction

45

4747

* The chemistry of aqueous tetrapropylammonium silicate solutions 48

* The isothermal metastable phase transformation 55

* The dominant factors influencing the crystallization of the MFI

1 The Si0

3 The degree of dilution or the H20/Si0 2 ratio 64

* The repartition of aluminium throughout the ZSM-5 crystal 91

* Synthesis of ZSM-5 from reactive mixtures prepared with unusual

in the presence of quaternary ammonium cations

in the presence of amines

in the presence of alcoholstemplates in ZSM-5 synthesis

in the absence of any organic compound

113

113119125132134144

CHAPTER III SYNTHESIS OF HIGH-SILICA ZEOLITES WITH THE MEL TYPE

* Introduction

* Quaternary salts used as templates in the synthesis of ZSM-ll

147147

* Parameters influencing the crystallization rate of ZSM-11

* Synthesis of the MEL structure type using diamines

* X-ray invisible ZSM-11 zeolites

* References

153157162166

CHAPTER IV POTENTIAL MEMBERS OF THE PENTASIL FAMILY OF

* Crystallographic structure of ZSM-5 and ZSM-11 167

* Intergrowths in the pentasil family of zeolites 177

* Experimental discrimination between pure ZSM-5, ZSM-11 zeolites and

* Overview of some pentasil-type zeolites claimed in the literature 188

* Synthesis of FER-type materials using inorganic gels 217

* Synthesis of FER-type zeolites in the presence of organics 220

* Differences between various proprietary FER-type materials 226

* Differences between the TON-type proprietary zeolites 248

CHAPTER VII: HIGH-SILICA ZEOLITES WITH MTT FRAMEWORK TOPOLOGY

CHAPTER IX : HIGH-SILICA ZEOLITES WITH MTW FRAMEWORK TOPOLOGY

* Potential family members of MTW zeolites

275

275275281281283284289295

297

297297303312319

CHAPTER X SYNTHESIS OF ZEOLITES THAT DO NOT BELONG TO THE

HIGH-SILICA AND/OR SHAPE-SELECTIVE CLASS OF ZEOLITES 321

* Synthesis of siliceous mordenite

* Materials with MTN structure type

* Siliceous Levynite zeolites

* Offretite-erionite zeolites and their intergrowths

* Faujasite-type siliceous zeolites

* References

321330333342343346

CHAPTER XI GENERAL CONSIDERATIONS 349

PART III BRIEF DESCRIPTION OF POTENTIAL HIGH-SILICA ZEOLITES

STUDIES IN SURFACE SCIENCE AND CATALYSIS

Advisory Editors: B Delmon, Universite Catholique de Louvain, Louvain-Ia-Neuve, Belgium

J.T Yates, University of Pittsburgh, Pittsburgh, PA, U.S.A.

Volume 1 Preparation of Catalysts I Scientific Bases for the Preparation of Heterogeneous

Catalysts Proceedings of the First International Symposium, Brussels, October 14-17,1975

edited by B Delmon, P.A Jacobs and G Poncelet

Volume 2 The Control of the Reactivity of Solids A Critical Survey of the Factors that

Influence the Reactivity of Solids, with Special Emphasis on the Control of the Chemical Processes in Relation to Practical Applications

by V.V Boldyrev, M Bulens and B Delmon

Volume 3 Preparation of Catalysts II Scientific Bases for the Preparation of Heterogeneous

Catalysts Proceedings of the Second International Symposium, Louvain-Ia-Neuve, September 4-7, 1978

edited by B Delmon, P Grange, P Jacobs and G Poncelet

Volume 4 Growth and Properties of Metal Clusters Applications to Catalysis and the

Photographic Process Proceedings of the 32nd International Meeting of the Societe

de Chimie Physique, Villeurbanne, September 24-28, 1979

edited by B Delmon and G.F Froment

Volume 7 New Horizons in Catalysis Proceedings of the 7th International Congress on

Catalysis, Tokyo, June 30-July 4, 1980 Parts A and B

edited by T Seiyama and K Tanabe

Volume 8 Catalysis by Supported Complexes

by Yu.1 Yermakov, B.N Kuznetsov and V.A Zakharov

Volume 9 Physics of Solid Surfaces Proceedings of a Symposium, Bechyi'ie, September

29-0ctober 3, 1980

edited by M Laznieka

Volume 10 Adsorption at the Gas-Solid and Liquid-Solid Interface Proceedings of an

International Symposium, Aix-en-Provence, September 21-23, 1981

edited by J Rouquerol and K.S.W Sing

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edited by B Imelik, C Naccache, G Coudurier, H Praliaud, P Meriaudeau, P Gallezot, G.A Martin and J.C Vedrine

Volume 12 Metal Microstructures in Zeolites Preparation - Properties - Applications.

Proceedings of a Workshop, Bremen, September 22-24, 1982

edited by P.A Jacobs, N.1 Jaeger, P Jiru and G Schulz-Ekloff

Volume 13 Adsorption on Metal Surfaces An Integrated Approach

edited by J Benard

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Asilomar, CA, September 1-4, 1982

edited by C.R Brundle and H Morawitz

Volume 15 Heterogeneous Catalytic Reactions Involving Molecular Oxygen

by G.! Golodets

Volume 16 Preparation of Catalysts III Scientific Bases for the Preparation of Heterogeneous

Catalysts Proceedings of the Third International Symposium, Louvain-Ia-Neuve, September 6-9, 1982

edited by G Poncelet, P Grange and P.A Jacobs

Volume 17 Spillover of Adsorbed Species Proceedings of an International Symposium,

Lyon-Villeurbanne, September 12-16,1983

edited by G.M Pajonk, S.J Teichner and J.E Germain

Volume 18 Structure and Reactivity of Modified Zeolites Proceedings of an Intenational

Conference, Prague, July 9-13, 1984

edited by P.A Jacobs N.! Jaeger, P Jiru V.B Kazansky and G Schulz-Ekloff Volume 19 Catalysis on the Energy Scene Proceedings of the 9th Canadian Symposium on

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edited by S Kaliaguine and A Mahay

Volume 20 Catalysis by Acids and Bases Proceedings of an International Symposium,

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edited by B lmelik, C Naccache, G Coudurier, Y Ben Taarit and J.C Vedrine Volume 21 Adsorption and Catalysis on Oxide Surfaces Proceedings of a Symposium,

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edited by M Che and G.C Bond

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Volume 24 Zeolites: Synthesis Structure Technology and Application Proceedings of an

International Symposium, Portoroz-Portorose September 3-8, 1984

edited by B Drza], S Hocevar and S Pejovnik

Volume 25 Catalytic Polymerization of Olefins Proceedings of the International Symposium

on Future Aspects of Olefin Polymerization Tokyo, July 4-6 1985

edited by T Keii and K Soga

Volume 26 Vibrations at Surfaces 1985 Proceedings of the Fourth International Conference,

Bowness-on-Windermere, September 15-19, 1985

edited by D.A King N.V Richardson and S Holloway

Volume 27 Catalytic Hydrogenation

edited by L Cerveny

Volume 28 New Developments in Zeolite Science and Technology Proceedings of the 7th

International Zeolite Conference, Tokyo, August 17-22 1986

edited by Y Murakami A lijima and J.W Ward

Volume 29 Metal Clusters in Catalysis

edited by B.C Gates L Guczi and H Knozinqer

Volume 30 Catalysis and Automotive Pollution Control Proceedings of the First International

Symposium, Brussels, September 8-11, 1986

edited by A Crucq and A Frennet

Volume 31 Preparation of Catalysts IV Scientific Bases for the Preparation of Heterogeneous

Catalysts Proceedings of the Fourth International Symposium, Louvain-Ia-Neuve, September 1-4,1986

edited by B Delmon P Grange P.A Jacobs and G Poncelet

Volume 32 Thin Metal Films and Gas Chemisorption

edited by P Wissmann

Volume 33 Synthesis of High-silica Aluminosilicate Zeolites

by P.A Jacobs and J.A Martens

TO JAN B UYTTERHOEVEN

Who we consider to be the founder of all this

It should be stressed that some of the data in this book, mainly the zeolitesynthesis recipes, might be the subject of patent claims It is not ourintention to violate any patent rights and the recipes should not be used forany other than strictly scientific purposes without checking that this is not

so In every case proper reference is made to what we consider to bepertinent patents

SCOPE OF THE WORK

This work certainly does not have the pretension to be a complement tothe famous books by Breck (refil ) and Barrer (reL2) and also it was notthe authors' aim to write an exhaustive review of high-silica zeolites First

of all, the zeolites denoted as high-silica are not well defined, from either

a scientific or a compositional point of view

Those using this term tacitly assume that high-silica zeolites withshape-selective properties are the subject of the discussion The termshape-selectivity has to be understood in the context used by those working

on catalysis in the petroleum or petrochemical area Consequently, as inthese areas one deals with relatively simple and small hydrocarbons, thezeolites concerned should contain ten-membered rings of T-atoms, belonging totetrahedra sharing corner oxygen atoms Zeolites with highly distortedtwelve-membered rings, exerting the same sieve effects, are also considered

to belong to this class of zeolites High-silica zeolites, in the authors'opinion, should be susceptible to synthesis over a wide compositional range.Those included generally can be synthesized with an Si02/A1 203 ratio varyingover at least one order of magnitude and consequently producing materials forwhich the composition varies over the same range The subject has beennarrowed still further, as only aluminosilicate zeolites are described Thepotential substitution of half of Mendeleev's table for aluminium in thesestructures is still a matter of debate and it is considered that an attempt

to rationalize the knowledge in this area would be premature As aconsequence of this narrowed scope, materials have occasionally been includedthat strictly are not zeolites, namely the so-called silica polymorphs withstructures identical with those of many high-silica zeolites The preparationmethods covered are also confined to direct synthesis methods Thepreparation of high-silica zeol ites by dealumination methods is notconsidered

Faced with the problem of keeping track of many new zeolites, or claimed

as such in the patent literature, with the help of many students andtechnicians a number of standard recipes have been established in the

"Laboratorium voor Oppervlaktechemie", under guidance of the authors Weconsidered it useful to offer this knowledge to the scientific comnuntty.Therefore, part of this book contains proven recipes for the synthesis ofcertain high-silica zeol~tes (and sometimes others) and data on theiridentification and characterization

Another objective was to review critically many of the claimed materialsand, based on the available data, to classify them into groups or families ofmaterials of the same structural type, whether this structure is knownalready or remains to be established It will be evident that thisclassification is based on the information available to the best knowledge ofthe authors at the time of writing and may be subject to changes in someins tances when pertinent i nforma t i on on the mostl y propri eta ry materi a1sisreleased Many data, mainly published in patents, have been discussed but

as none of the authors is familiar with the Japanese, Chinese or Russianlanguages, it might well be that essential information has been overlooked

In principle, the literature has been covered up to the end of 1985.Particularly relevant work which appeared in the first half of 1986 was addedafterwards

As mostly newly claimed crystalline materials in this area of scienceare identified based on their X-ray diffraction patterns, the authors havedefined a specific layout of these patterns, containing all necessary datafor collecting them in a personal 1 ibrary useful for the identification ofpotentially new products synthesized by readers

1 D.W Breck, Zeolite Molecular Sieves, Wiley, 1974

2 R.M Barrer, Hydrothermal Chemistry of Zeolites, Academic Press, 1982

ACKNOWLEDGEMENTS

The authors particularly appreciate the stimulating influence of Jan B.Uytterhoeven duri ng the past 20 years, and consequently they deci ded todedicate this book to him The senior author also acknowledges continuoussponsoring of his research activities by the National Fund for ScientificResearch (Belgium) and more recently to K.U Leuven to allow him to teach inthis area of science The junior author is also grateful to the National Fundfor Scientific Research (Belgium) for several research fellowships

OF HIGH-SILICA ZEOLITES

INTRODUCT ION

Zeol ites in general and high-sil ica zeol ites more in particular areoften crystall ized by nucleation from inhomogeneous supersaturated motherliquids Therefore, the origin, purity and exact chemical composition of thereactants used for their synthesis may sometimes be critical The commercialorigins and grades of the reagents used in this chapter in the recipes forthe synthesis of high-silica zeolites are given in Table 1.1. They are notnecessarily the most advantageous reactants for the synthesis of bulk amounts

of zeolites but their prices are such that the average budget of a universitylaboratory will permit the synthesis of kilogram amounts of these materials.The recipes advanced here are highly reproducible They were checkedindependently by two laboratory technicians Each synthesis was carried out

in home-made stainless-steel autoclaves, which could be equipped with a PTFEcoating or a glass 1iner A drawing representing the PTFE-l ined version ofthese autoclaves is shown in Fig 1.1

Twenty of such autocl aves coul d be mounted together ina furnace andheated while they are being rotated at 50 rpm (rotations per minute) In eachautoclave from 10 to 15 g of zeolite on a dry calcined basis can generally berecovered

GENERAL PROCEDURE USED FOR THE SYNTHESIS OF HIGH-SILICA ZEOLITES

For the synthesis of high-silica zeolites, in most instances twosolutions are prepared Solution A contains the organosilicate and solution B

is prepared by dissolving successively in water the inorganic base(s) and thealuminium salt Solution A is prepared by adding the organic molecule (or itssolution) to the silicate solution for all silica sources except Aerosil Inthe latter instance, the silica powder is added with continuous stirring to

an aqueous solution of the organic material Solution B is added slowly to Awith vigorous st i rri ng, and the pH iss ubsequent ly adj usted by dropwi seaddition of a mineral acid The gel thus obtained is then autoclaved; theautoclaves are mounted in the heated furnace and are continuously rotated at

50 rpm during synthesis The synthesis efficiency is defined as the weight

TABLE 1.1

Origin of reactants used in the recipes for the synthesis of high-sil icazeolites

Silicic acid Riedel-De Haen

TEO-sil icatea Merck

TechnicalPro analysiPurum

Pro analysiPro analysi

a, tetraethyl orthosilicate; b, tetramethylammonium; c, tetraethylammonium; d,tetrapropylammonium

percentage of Si02 + A1

203 that is recovered after the whole operationcompared with the Si02 + A1203 in the gel This operation includes synthesis,several washings (to neutral pH), air drying at 325 K and air calcination at

823K

In every instance, the recipes are optimized synthesis methods which toour knowledge give maximum efficiency The zeolites thus obtained are phasepure and also are free from significant amounts of residual amorphousmaterial The phase purity was checked by comparing the peaks in the X-raydiffractograms (XRD) with those given in the 1iterature Using scanningelectron microphotographs, it was decided whether residual amorphous materialwas present

SPECIFIC RECIPES

1 Synthesis of lSM-34

1.a ~t~!~~~!~_9f_~~~:~~_~!!~_I~~:Q~_~~_9~9~~!~_~~~~

Solution A 42 ml TMA-OH (2.5 M) + 27.2 g silicic acid

Solution B 118 g water + 5.5 g sodium hydroxide + 5.2 g sodium

aluminate

Mixing was carried out in an ice-bath and afterwards concentratedsulphuric acid was added dropwise until a pH of 11 was reached.Synthesis occurred at 353 Kfor 7 days with stirring The gel had thefollowing molar composition:

The efficiency of the synthesis method was about 80 % The Si/A1Zratio

of the zeolite was 15 This method is original and has not been derived,

as far as we are aware, from eXisting information Individual elongatedcrystals about 1 ~m long dominate (Photograph 1.1), and the presence of

a small number of 0.2-0.4 ~m crystals is indicative of secondarynucleation

1.b ?~~!~~~1~_~!_~?~:~~_~1!~_I~~_~~9_1~_e~~~~~~~_~!_~_~1:~9_~l~~l1:~~~~~~

Solution A 33.3 9 Ludox AS30 + 3.2 g TMA-OH (25 %, aqueous)

Solution 8: 2.5 9 KOH + 7.4 9 NaOH + 3.9 NaA102 + 10 9 water

Botf solutions, pre-cooled in ice, were mixed together at the sametemperature and autoclaved at 463 K for 2 h with continuous agitation.The gel had the following molar composition:

The efficiency of the method was 70 % The Si/A12 ratio of the zeolitewas 12

I.e ~~~!~~~~~_~!_~~~:~~_~~!~_~~~l~~~_~~_~~~~~~~_~~l~~~l~

{~~~~~~_!~~~_~~!~_!!_~~~~~l~_!Q2

Solution A: 45 g Aerosil in 155 g water

Solution B : 17 g NaA102 +6 g NaOH + 5.6 g KOH + 110 g H20

This solution was stirred until it became transparent and then 50 g ofcholine chloride were added

Solution A was mixed with B; the final gel was then autoclaved at 423 Kfor 8 days with continuous agitation The gel had the following molarcomposition:

in which R represents the choline molecule The efficiency was 80 % andthe ZSM-34 showed an Si/A12 ratio of 10

The XRD of ZSM-34 looks like the one of offretite materials and possiblythe material belongs to the offretite-erionite family

2 Synthesis of ferrierite/ZSM-35-type materials

Based on their X-ray diffractograms, ZSM-35, -38 and -21 and ferrieriteare not easily distinguishable and therefore belong possibly to the samefamily of zeolites The distinction made in this paragraph betweenferrierite and ZSM-35 is therefore only formal The crystalline solid isdenoted according to the notation used in the initial publication fromwhich the present materials are derived

2.a ~~~!~~~~~_~!_~~~:~~_~~_!~~_~~~~~~~~_~!_~!~~l~~~~~~~~~~

{~~~~~~~_!~~~_~~!~_~l_~~~~pl~_§2

Solution A 46.47 g Ludox AS30 + 18.3 g ethylenediamine (C2DN)

Solution B : 129 g H20+ 0.7 g NaOH + 3.3 g NaA102

Solution A was mixed with B

Crystallization: 10 days at 450 K with agitation

In this way, a gel with the following molar composition

was transformed into crystalline ZSM-35, with an efficiency of 60 % andgiving an Si/A1 2 ratio of 13 The crystals were elongated with a length

of about 1 urn (Photograph 1.2)

PHOTOGRAPH 1.2 SEM of lSM-35.

2.b ~~~!~~~!~_~!_~~~:~~_!~_!~~_~~~~~~~~_~!_~~~~~!!~!~~

i~~~!~~~_!~~~_~~!:_~1_~~~~~!~_!~2

Solution A 48.39 9 Ludox AS30 + 8.25 9 pyrrolidine

Solution B : 0.5 9 NaOH + 3.3 9 NaA102 + 136 9 H20

Solution A was mixed with B Crystallization occurred at 450 K during aperiod of 15 days The molar composition of the gel was

in which R represents pyrrolidine The efficiency of this synthesis was

65 %, and the zeolite had an Si/A12 ratio of 15

Z.c ?t~!b~~1~_2!_!~~~1~~1!~_~1!b_!2~_~!_~2~!~~!_~~2~9_E2E~~192~~

i~9~E!~9_!~2~_~~!~_~1_~~~~E!~_~2

Solution A Zl.l g water glass + 3.1 g piperidine

Solution B : ZZ.l g HZO + 1.3 g A1Z(S04)3.18HZO

Synthesis conditions : 473 K for 1 day with agitation The molarcomposition of the gel was

in which R represents piperidine The efficiency of the synthesis was

60%and the Si/A1Z ratio of the zeol ite was 40 In contrast to thestatement in the original patent, it was found that using our rawmaterials, a more crystalline material was obtained at a crystallizationtemperature that was 50 Khigher

Z.d ~t~!b~~!~_2!_!~~~!~~!!~_~!!b_~!~~9~~9_~b~~!~~!_~2~e2~!!!2~_~~!~9

e!E~~!9!~~_i~9~e!~9_!~2~_~~!~_~1_~~~~E!~_~2

Solution A 18.6 g Ludox AS30 + 3.1 g piperidine

Solution B : ZZ g HZO + Z.Z g NaOH + Z.7 g A1Z(S04)3.18HZO

Synthesis conditions : 473 K for 1 day with agitation The molarcomposition of the gel was

in which Rrepresents piperidine The efficiency was 65 %and the Si/A1Zratio of the zeol ite was ZO The modification consisted in the use ofLudox as the silica source and in an increase of the synthesistemperature by 50 K

3 Synthesis of lSM-39

3.a ~t~!b~~!~_2!_~~~:~~_~2!b_e!e~~!92~~_~~_!b~_2~9~~!~_~~!~~!~!

This recipe was derived from a method which in the original patent (ref.3) produced ferrierite The synthesis temperature was increased by 50 Kand the pH of the gel was lower, as sulphuric acid was added Based onexample 8, the following recipe is then obtained:

Solution A 21.1 g water glass + 3.1 g piperidine

Solution B 1.3 g A12(S04)3.18H20 in 20 g water

Solution B was added to A with stirring and sulphuric acid was addeddropwise until the pH reached a value of approximately 10.5 Synthesiswas carried out at 473 K for 3 days The molar composition of the gelwas

in which R represents piperidine The efficiency of the synthesis was

100 % and the Si/A12 ratio of the zeolite was 50

3.b ?~~!~~~~~_~!_~!:!~~~_~?~:~~_~~!~_~!~~!~~~~~_~~9_I~~

In contrast to the procedure followed in the original patent (ref 4),TMA-Cl was replaced with TMA-Br and propyl amine with ethylamine Whenthis was done, very pure ZSM-39 was obtained instead of ZSM-48, asclaimed in the patent

Solution A 18.7 g water glass + 39.3 g water + 1.7 g concentrated

sulphuric acidSolution A* 4.2 g TMA-Br in 8.7 g ethyl amine (C2N) (70 %aqueous) +

36.7 g water

Solution A* was slowly and under stirring added to A The gel with thefollowing molar composition:

((TMA)20)13.7 (C2N)135.4 (Na20)38.3 (Si0 2)82.4 (H20)5,091

was transformed into Al-free ZSM-39 after a synthesis period of 2 days

at 433 K The efficiency of this synthesis was 100 %, which indicatesthat all the sil ica present in the gel was transformed completely intocrystalline silica

4 Synthesis of high-silica ZSM-6 with TMA

Example 1 of ref 5 has been modified by replacing TMA-Cl with TMA-Br,increasing the synthesis temperature by 30 K and decreasing thesynthesis time from 6 to 3 days In this way ZSM-6 with a variableSi/A12 ratio could be obtained It has been checked that the methodworks within the range 200 < Si/A12 < 1000

The final zeol ite lSM-6 had an Si/A1

2 ratio of 250 and thecrystallization efficiency was 75 %

5 Synthesis of high-silica mordenite

Natural or synthetic mordenite, synthesized in the absence of organics,always has a very typical Si/A12 ratio, between 9 and 10 (ref 6) Whenorganics are added during the synthesis an enhanced Si/A12 ratio can beobtained

5.a ~!9b:~!!!~~_~9~~~~!!~_~!!b_E!E~~!~!~~

When in example 9 of ref 3, Ludox is used as the silica source and thesynthesis temperature is increased by 50 K, mordenite instead offerrierite is crystallized When the same amounts were used as inSection 2.d., the crystalline mordenite had an Si/A1 2 ratio of 30

In this recipe TEA-Br was used instead of a TEA-OH solution and waterglass was the silica source In the original work (ref 7, example 4)lSM-12 was obtained

was converted into a crystalline high-silica mordenite The efficiency

of the operation was only 60 %

The composition of the gel was :

ZSM-12 was obtained after heating the gel at 453 K for 7 days withoutagitation in a glass lined autoclave

6.b ~?~:!~_~~!~S_I~~_~~9_~~!~!~~!~~

Solution A 18.67 g of water glass + 30 g water + 1.7 g of

concentrated sulphuric acidSolution A* 7.48 g of TMA-OH (25 %) + 33.5 g water + 18.10 g

octylamine (C8N)Solution B : 1.24 g Al(N03)3.9H20 in 10 g water

Solutions A* and B were added to A under stirring The final gel

was autoclaved during 5 days at 433 K The morphology of this sample isvery peculiar, as shown in Photograph 1.3 Large cylindrical crystals(5 x 1 IJm) were present in addition to very small ones (0.1-0.4 IJm).This is definitely an example of secondary nucleation Microprobeanalysis in a region where these small crystallites were highlyagglomerated allowed the calculation of an Si/A12 ratio of about 400,while the large crystals covered with smaller ones had Si/A12 ratios ofapproximately 25 The overall Si/A12 ratio of the sample was 50

PHOTOGRAPH 1.3 SEM of ZSM-12.

Hence it seems that first large Al-richer ZSM-12 crystals are formed (5

x 1 ~m) and at a given moment when the mother liquid has become rich insilica the same structure starts to nucleate again and grows to smallercrystals with a higher Si content

In this example a procedure for the synthesis of ISM-48 was modified(ref 4, example 1) as follows: (i) aluminium was added to the gel,(ii) TMA-Cl was replaced with TMA-OH, (iii) octylamine was used instead

of propylamine and (iv) the synthesis time was extended from 2 to 5days

7 Synthesis of zeolite PHI

In an attempt to synthesize zeolite ZSM-ZO, which is of the faujasitefamily (ref 8), zeolite PHI (ref 9) was systematically obtained

Solution A: obtained when Z5.6 g of TEO-silicate was slowly hydrolysed

in 4Z.4 g TEA-OH (40 %) and the ethanol formed wasdistilled off

Solution B contained 1.3 g NaA10Z' which was added to 36 g water with

0.13 g NaOH

Solution B was then added to A with stirring This mixture was firstaged at 277 K for Z days and finally autoclaved at 373 K for 14 dayswithout agitation The following gel:

was transformed in this way into a highly crystalline zeolite PHI withvery particular morphology, as shown in Photograph 1.4

It should be noted that the notation "PHI" here does not representphill ipsite zeol ite, as might be assumed when abbreviations that havebeen suggested for the notation of zeol ite structure types are used(ref 10)

PHOTOGRAPH 1.4 SEM picture of zeolite PHI

8 Synthesis of zeolite BETA

Another zeolite that is often crys ta 11 i zed when TEA is present as anorganic material (ref 11) is BETA It also often crystallizes when theprocedures for ZSM-20 synthesis (ref 8) are only slightly modified

A first recipe is derived from original patent (ref 11) without anymajor modification

Solution A

Solution B

72.7 g Ludox AS403.9 g NaA102 in 30 g water + 37 ml TEA-OH (40 %)

The gel obtained after addition of solution A to B

was aged in an autoclave for 10 days at 423 K After this period zeoliteBETA with an Si/A1 2 ratio of 31 was obtained, with the morphology shown

in Photograph 1.5

PHOTOGRAPH 1.5 SEM of zeolite BETA

The recipe for ZSM-ZO (example 1 of ref 8) was modified in the

fo 11 owi ng way : (i) tetraethyl orthos il i cate was used instead of themethyl form, (ii) the synthesis time was limited to Z instead of 4 weeksand (iii) the synthesis temperature was increased by ZO K

To a solution of 1.3 9 NaA10 Z+ 4Z.6 9 TEA-OH (40 %) + 0.36 9 NaOH + 8 9water, TEO-silicate (38.5 g) was added dropwise The ethanol formedduring the TEA-silicate hydrolysis was distilled off and the gel withfollowing composition

was then autoclaved at 393 K for Z weeks, without stirring Crystallinezeolite BETA was obtained with an Si/A1Zratio of 31

9 Synthesis of zeolite ZSM-Z5

A zeolite ZSM-Z5 with a morphology s imil ar to that of zeol i te BETA(Photograph 1.5) was obtained using a procedure described earlier in thepatent literature (ref 1Z) However, Aerosil was used instead ofcolloidal silica In this way a solution A was prepared by dissolving

33 9 of TEA-Br in 39 9 of water; 6.84 9 of Aerosil mixed with ZO,3 9 HZOwere then stirred into this solution Solution B contained 3 9 ofNaA10 Z' 0.9 9 of NaOH and 15 9 of water

The gel obtained after mixing both solutions :

was agitated for 5 days in an autoclave at 408 K

10 Synthesis of ZSM-5 with TPA

Photograph 1.6 shows three crystal morphologies of ZSM-5, which wereobtained with recipes that will be described in detail

PHOTOGRAPH 1.6 SEM crystals of ZSM-5 prepared according to therespective recipes.

10.a In this method a relatively diluted gel is used The method is derivedfrom the work of von Ballmoos (ref 13) It gives large elongatedhexagonal prisms as crystal "habitus" and, as Photograph 1.6 shows, theyare single and not twinned To obtain this material the followingsolutions were mixed:

From the resulting gel with the following molar composition

ZSM-5 was crystallized after 3 days at 423 K This zeolite had an Si/A12ratio of 70

10.b Using a more concentrated gel, slightly smaller single crystals of ZSM-5with distinct morphology were obtained under the same synthesisconditions

Solution A to 11.1 g Aerosil in 1.6 g NaOH and 32 g water, 2.5 g

TPA-Br in 78 g water were addedSolution B : 0.6 g NaA102 in 10'g water

The pH of the final gel was adjusted to 11 with sulphuric acid

The final gel

was then crystallized in the same way as in the previous method

10.c When water glass is used as the silica source, ZSM-5 with a totallydifferent morphology is obtained (agglomerates of smaller elementarycrysta11 ites)

In addition to a distinct morphology, the three preparations aftercalcination at 823 K, NH; ion exchange and subsequent heat treatment at

673 K also show a distinct infrared absorption spectrum in the hydroxylstretching zone (Fig 1.2)

FIGURE 1.2 Hydroxyl stretching spectrum of ISM-5 samples prepared according

to methods lOa, lOb and 10c after removal of residual organics and Na+ ions

11 Synthesis of ISM-II

Pure ISM-II samples, which means that all the XRO lines of these samplescoul d be indexed ina tetragonal symmetry, caul d only be synthes i zedusing either tetrabutylphosphonium ions (TBP) or in the presence of1,8-diaminooctane As TBP became difficult to obtain commercially, onlythe recipe using 1,S-diaminooctane (CSON) will be presented

Solution A

Solution B

40 ml water glass + 1.3 9 CSON in 3S g water0.7 g NaA102 in 40 9 water

The pH of the final gel was adjusted to 11 with sulphuric acid.

The gel obtained

was autoclaved at 423 K for 3 days A pure ZSM-ll with the morphologyshown in Photograph 1.7 was then obtained

PHOTOGRAPH 1.7 SEM picture of pure ZSM-11

12 Synthesis of ZSM-8

12.a ~t~!~~~!~_~!_~~~:§_!~_!~~_E~~~~~~~_~!_!~~_l~!!~~_~~!:_ ! ~ 2

Solution A : 50 g Ludox AS30 + 10 g TEA-OH (40 %)

Solution B : 1.~ g NaA102 + 0.1 g NaOH + 30 g water

Solution A was added to B

The synthesis of the resulting gel was carried out in a glass-linedautoclave for 7 days at 453 K The gel composition was

12.b ~t~!~~~~~_2f_~~~:~_~~_P~~~~~~~_2f_Pt~~2l~9~~~

When the procedure of ref 15, exampl e 9, is followed and thecrystallization time is extended from 5 to 10 days, lSM-8 is obtainedinstead of lSM-23

Solution A : 98.3 9 Ludox AS40 + 14.6 9 pyrrolidine

Solution B : 0.6 9 NaA102 in 56.8 9 water and 0.2 9 NaOH

Solution A was mixed with B The following gel

in which R represents pyrrol idine, was autoclaved at 453 K and gavelSM-8 with an Si/A12 ratio of 300

13 Synthesis of lSM-48

When example 1 of a patent (ref 4) in which the synthesis of lSM-48 isdescribed, is modified as follows: (i) TMA-Cl is replaced with TMA-Br,(ii) propylamine is replaced with octy1amine and (iii) the synthesistime is reduced from 2 days to 1 day, then a recipe is obtained thatallows the synthesis of lSM-48 in the following compositional range:

100 <Si/A12 <00.

Solution A: to 18.7 9 water glass and 29.3 9 water was first added

1.7 g sulphuric acid After vigorous stirring were added4.2 9 TMA-Br + 41 9 water + 18.1 g octylamine (C8N)

Solution B: 0.6 9 Al(N03)3.9H20 in 10 9 water

The gel composition was :

The gel was agitated in an autoclave for 1 day at 433 K

The crystals had the shape of bundles of needles, their size beingdependent on the amount of Al present in the gel Photograph 1.8 clearlyillustrates this morphology It also shows that from a gel that containsonly aluminium as impurity in the other reactants, needles are obtainedthat are up to five times longer than those crystall ized from thesilica-alumina gel described in the present recipe

PHOTOGRAPH 1.8 SEM pictures of lSM-48 crystals: (a) with no Al added to thegel and (b) with an Si/A1 2 ratio of the gel of 100.