9 Crystallization of Zeolitic Aluminosilicates in the System Li O-Na O-Al O -SiO -H O at 100° C Downloaded by PRINCETON UNIV on August 26, 2013 | http://pubs.acs.org Publication Date: August 1, 1974 | doi: 10.1021/ba-1971-0101.ch009
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2
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H. BORER and W. M. MEIER Institut fürKristallographieund Petrographie, Eidgenössische Technische Hochschule, Sonneggstrasse 5, Zürich, Switzerland
Crystallization sequences have been determined for over 400 compositional points in the Li,Na-aluminosilicate system at 100°C and reaction times of up to 14 days. A total of 9 zeolitic species has been observed thereby. Crystallization times and the nature of the first appearing solid phase depend largely on the lithium and sodium concentrations. The same crystallization sequences occur within certain fields, and these sequences are nowhere reversed. A simple scheme illustrating the relative stabilities of the solid phases in the system is presented.
he most open zeolites crystallize at relatively low temperatures from highly reactive alkali aluminosilicate gels. These zeolitic phases are metastable, and usually several phases are formed in succession from a particular reaction mixture. This paper describes crystallization sequences observed in mixed Li,Na-alummosilicate gels at 100°C. The details of our investigation of this system at 100°C are reported elsewhere (8,9). A
Crystallization fields of zeolites growing from homocationic Na gels at around 100 °C have been studied extensively at a number of laboratories (cf. 3,11, 21). Sand and coworkers recorded the coexisting phases for different reaction times (19). The kinetics of zeolite crystallization in the Na system also has received attention (12, 14, 15). Studies of lowtemperature crystallizations from L i gels, on the other hand, have been much more limited (13). 122 In Molecular Sieve Zeolites-I; Flanigen, E., et al.; Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
9.
BORER
A N D
MEIER
Zeolitic
123
AluminosiUcates
Experimental Well-defined starting materials were chosen w h i c h were combined a c c o r d i n g to a s t a n d a r d p r o c e d u r e i n o r d e r to a s c e r t a i n m a x i m u m r e p r o d u c i b i l i t y . H i g h l y r e a c t i v e gels w e r e p r e p a r e d thus f r o m reagent g r a d e l i t h i u m a n d sodium hydroxide, tetramethoxysilane, a n d analyzed s o d i u m a l u m i n a t e c o n t a i n i n g excess caustic. M e a s u r e d a m o u n t s of 2 M N a O H , 2 M freshly prepared Na-aluminate solution, deionized water, ( C H 0 ) S i , a n d 2 M L i O H w e r e c o m b i n e d i n t h i s o r d e r at r o o m t e m p e r a t u r e a n d v i g o r o u s l y s t i r r e d to p r o d u c e h o m o g e n e o u s gels. A n u m b e r of test e x p e r i ments s h o w e d t h e r e w a s n o n e e d to r e m o v e t h e s m a l l a m o u n t s of m e t h a n o l w h i c h f o r m e d i n the r e a c t i o n m i x t u r e s . T h e d r y w e i g h t of the constituents w a s a b o u t 65 m g / m l i n a l l e x p e r i ments. T h e m o l a r ratios of the c o m p o n e n t s w e r e b a s e d o n Downloaded by PRINCETON UNIV on August 26, 2013 | http://pubs.acs.org Publication Date: August 1, 1974 | doi: 10.1021/ba-1971-0101.ch009
3
n(Li 0) + 2
rc(Na 0)
4
+ n(Al 0 ) + n(Si0 ) = 1
2
2
3
2
T h e concentrations of a l l c o m p o n e n t s except w a t e r w e r e v a r i e d s y s t e m a t i c a l l y i n steps of Δ η = 0.05 w i t h i n t h e f o l l o w i n g l i m i t s : n(Si0 )/n(Al 0 ) > 2
n(Na 0)/n(Al 0 ) > 2
2
3
2
3
0.5
1.25 a n d n ( A l 0 ) > 2
3
0.05.
A t o t a l of 448 c o m p o s i t i o n a l p o i n t s of t h e system h a d to b e e x a m i n e d as a consequence. A l l c r y s t a l l i z a t i o n s w e r e c a r r i e d out i n sealed p o l y p r o p y l e n e tubes of 3 0 - 4 0 - m l c a p a c i t y . G l a s s w a s a v o i d e d p u r p o s e l y i n a l l o u r experiments since i t is a t t a c k e d r e a d i l y b y the reactants u s e d a n d t h e crystals n u c l e a t e m o s t l y o n the glass w a l l s . I n p a r t i c u l a r , w e h a v e n o t e d t h a t r e p r o d u c i b i l i t y of L i , N a - z e o l i t e c r y s t a l l i z a t i o n s is e x c e e d i n g l y p o o r w h e n c a r r i e d out i n b o r o s i l i c a t e glass e v e n at r e l a t i v e l y l o w t e m p e r a t u r e s . T h e p o l y p r o p y l e n e tubes c o n t a i n i n g the reactants w e r e r o t a t e d s l o w l y ( a b o u t 8 r e v o l u t i o n s p e r m i n u t e ) at 1 0 0 ° C i n t h e r m o s t a t i c a l l y c o n t r o l l e d ovens. S a m p l e s of the r e a c t i o n m i x t u r e s w e r e t a k e n after 3 h r s , 18 h r s , 112 hrs, a n d 14 days. T h e s o l i d p r o d u c t s w e r e filtered off a n d w a s h e d t h o r o u g h l y w i t h d i s t i l l e d w a t e r . T h e d r i e d solids w e r e a l l e x a m i n e d u n d e r t h e m i c r o s c o p e a n d i d e n t i f i e d b y means of x - r a y p o w d e r patterns u s i n g a G u i n i e r c a m e r a . S e l e c t e d samples w e r e c h a r a c t e r i z e d f u r t h e r b y means of c h e m i c a l analyses, d e n s i t y a n d s o r p t i o n m e a s u r e m e n t s , e l e c t r o n m i c r o s c o p y , a n d t h e r m a l analyses ( D T A a n d T G A ) . Description
of the Solid Phases
A t o t a l of 9 zeolites a n d 3 n o n z e o l i t i c solids c o u l d b e o b s e r v e d .
These
species, w h i c h are s u m m a r i z e d i n T a b l e I , c a n b e d i v i d e d i n t o the f o l l o w i n g g r o u p s : species a p p e a r i n g i n the N a system ( A , P , S , T , X , Z ) , i n the L i system ( Η , Ι , Ν ) , a n d those r e q u i r i n g b o t h L i a n d N a ( C , E , 0 ) .
Species
X a n d Ζ w e r e o b t a i n e d o n l y i n r e l a t i v e l y f e w experiments i n the h i g h N a 0 / L i 0 region. 2
2
Ρ a n d Τ p i c k u p o n l y m i n o r a m o u n t s of h t h i u m . Ρ is a l w a y s s p h e r u l i t i c , w h e r e a s Τ n o r m a l l y forms v e r y s m a l l p r i s m s s h o w i n g w e l l - d e v e l o p e d
In Molecular Sieve Zeolites-I; Flanigen, E., et al.; Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
124
MOLECULAR SIEVE ZEOLITES
Table I.
Linde A Faujasite Na-Pl Na-P2 Sodalite hydrate Cancrinite hydrate Chabazite-like L i - A (Barrer) Li-metasilicate Li-aluminate K - F (Barrer) new
X
a
pa f a
s* C Z H I Ν E Ο a
a
a
a
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Crystalline Species and Notation Type
Symbol
1
Other Designations
and
References
A(10,16,19), Q(3) X ( J 7 ) , F(19), R(3) cubic P ( S ) , P I ( 4 ) , P ( J 0 ) , B(J«) tetrag. P(S), P2(4), Pt(ifl) 8(19), 1(3), Z\i(20) C(7,19) 8(3), Ε (00) A(6) (13) (13) Έ(2) e
Zeolite.
a
faces.
D T A - c u r v e s of Ρ a n d Τ ( o f s i m i l a r c o m p o s i t i o n )
a b l y different.
are also r e m a r k
S t r u c t u r a l l y , Ρ is a n i s o t y p e of g i s m o n d i t e a n d n o t t r u l y
cubic ( J ) . T h e fibrous crystals of C t a k e u p l i t h i u m p r e f e r a b l y . P u r e samples of C c a n b e o b t a i n e d r e a d i l y i n g o o d y i e l d f r o m L i , N a gels. E , a n i m p o r t a n t phase i n t h e L i , N a system, appears as n e e d l e - l i k e crystals or
aggregates
w i t h a constant S i / A l r a t i o of 1. T h e p o t a s s i u m - e x c h a n g e d f o r m is i d e n t i c a l w i t h K - F , w h i c h w a s t h o u g h t to b e a t y p i c a l p r o d u c t i n the p o t a s s i u m field
(5).
U n e x c h a n g e d crystals of Ε c o n t a i n a p p r e c i a b l e amounts
of
both L i and N a . H i g h L i concentrations are r e q u i r e d f o r the f o r m a t i o n of Η a n d O . Species O , w h i c h crystallizes v e r y s l o w l y as t i n y needles, has not r e p o r t e d before.
A representative s a m p l e s o r b e d 4 . 8 %
been
H 0 reversibly 2
a n d c o n t a i n e d a l a r g e excess of a l k a l i ( m o s t l y L i ) w h i c h c o u l d n o t b e removed.
F o r this reason, Ο does not a p p e a r to b e a t y p i c a l zeolite.
Crystallization
Sequences
T y p i c a l examples of c r y s t a l l i z a t i o n sequences are g i v e n i n T a b l e I I . H i g h a l k a l i n i t y b r i n g s a b o u t faster c r y s t a l l i z a t i o n rates a n d t h e fastf o r m i n g A a n d / o r Ε are f r e q u e n t l y t h e first a p p e a r i n g phases. T h e n a t u r e of the phase f o r m i n g i n i t i a l l y d e p e n d s m o s t l y o n the H t h i u m a n d s o d i u m concentrations, as i n d i c a t e d i n T a b l e I I . A s a r u l e , Ε appears first a b o v e n ( L i 0 ) =0.35. 2
T h e o b s e r v e d c r y s t a l l i z a t i o n sequences are s h o w n i n F i g u r e 1.
They
are a l l b a s e d o n r e c o r d e d changes i n t h e p o w d e r patterns. T h e f r e q u e n c y of a p a r t i c u l a r sequence is i n d i c a t e d b y the w i d t h of the respective a r r o w . Species w h i c h m a y a p p e a r first are e n c l o s e d i n circles.
I n some areas,
In Molecular Sieve Zeolites-I; Flanigen, E., et al.; Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
9.
Zeolitic
BORER AND MEIER
Table II. Composition
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Some T y p i c a l Crystallizations
of Reaction
Mixture
Products
n(Li 0)
n(Na 0)
n(Al O )
n(Si0 )
0.05 0.10 0.30 0.35 0.45 0.40 0.20 0.60 0.35 0.25 0.05 0.05 0.05 0.10 0.05 0.15
0.80 0.70 0.50 0.45 0.35 0.40 0.55 0.15 0.35 0.45 0.60 0.50 0.45 0.35 0.35 0.25
0.05 0.10 0.10 0.10 0.10 0.05 0.10 0.05 0.10 0.10 0.10 0.25 0.10 0.20 0.10 0.15
0.10 0.10 0.10 0.10 0.10 0.15 0.15 0.20 0.20 0.20 0.25 0.20 0.40 0.35 0.50 0.45
2
α
2
125
Aluminosilicates
2
s
2
of
3 hrs
18 hrs
A A ae ae Ε Ε ae
A A ce ce Ε Ε ae
ce A
ce aec at A Ρ A
—
— A
— — — —
—
— Ρ
Crystallization
11
112 hrs 14 days st A C C H ho E 0 ch ce Τ A Ρ ac pt Ρ
Τ as C ch H ho E O H C Τ A Pi ac Τ hp
Small letters denote components of mixture.
Figure 1.
Crystallization
sequences
phases I a n d Ν start f o r m i n g ( n o t a b l y i n l o n g r u n s ) w i t h o u t d i m i n i s h i n g the m a i n p r o d u c t .
T h e s e less significant changes
are r e p r e s e n t e d
by
d o t t e d lines i n F i g u r e 1. Well-established
sequences
A - E - C , A - S - T , and E - C - H .
i n v o l v i n g over
2 z e o l i t i c species
E a c h of t h e r e c o r d e d sequences
observed w i t h i n a certain composition
field.
are
can be
T h e s e fields are better d e
fined t h a n the " c r y s t a l l i z a t i o n fields" w h i c h d e p e n d o n factors c o n t r o l l i n g the r e l a t i v e rates of g r o w t h ( 1 5 ) .
In Molecular Sieve Zeolites-I; Flanigen, E., et al.; Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
126
MOLECULAR SIEVE ZEOLITES
1
All reactions proceed in one direction; i.e., the sequences are never reversed and reactions such as A - C and A - T do not occur at the same time. Figure 1, therefore, represents a scheme of the relative stabilities of the species in the system. Acknowledgment This study was supported by the Schweizerische Nationalfonds and a grant from the Mobil Oil Corp.
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Literature Cited (1) Baerlocher, Ch., Meier, W. M., to be published. (2) Barrer, R. M., Baynham, J., J. Chem. Soc. 1956, 2882. (3) Barrer, R. M., Baynham, J., Bultitude, F. W., Meier, W. M., J. Chem. Soc. 1959, 195. (4) Barrer, R. M., Bultitude, F. W., Kerr, I. S.,J.Chem. Soc. 1959, 1521. (5) Barrer, R. M., Cole, J., Sticher, H.,J.Chem. Soc. (A) 1968, 2475. (6) Barrer, R. M., White, E. A. D.,J.Chem. Soc. 1951, 1267. (7) Ibid., 1952, 1561 (8) Borer, H., Ph.D. Thesis, ΕΤΗ Zurich, 1969. (9) Borer, H., Meier, W. M., to be published. (10) Breck, D. W., Eversole, W. G., Milton, R. M., Reed, T. B., Thomas, T. L., J. Am. Chem. Soc. 1956, 78, 5963. (11) Breck, D. W., Flanigen, E. M., S.C.I. Monograph Mol. Sieves 1968, 47. (12) Ciric, J.,J.Colloid Interface Sci. 1968, 28, 315. (13) Gusseva, I. V., Liliev, I. S., Zh. Neorgan. Khim. 1965, 10, 92. (14) Kerr, G. T.,J.Phys. Chem. 1966, 70, 1047. (15) Ibid., 1968, 72, 1385. (16) Milton, R. M., U. S. Patent 2,882,243 (1959). (17) Ibid., 2,882,244 (1959). (18) Ibid., 3,008,803 (1961). (19) Regis, A. J., Sand, L. B., Calmon, C., Gilwood, M . E., J. Phys. Chem. 1960, 64, 1567. (20) Zhdanov, S. P., Izv. Akad. Nauk SSSR, Ser. Khim. 1965, 950. (21) Zhdanov, S. P., S.C.I. Monograph Mol. Sieves 1968, 62. RECEIVED February 4, 1970.
In Molecular Sieve Zeolites-I; Flanigen, E., et al.; Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
