Zeolite Formation in the System K

15 Zeolite Formation in the System K O-Na O-Al O -SiO -H O 2

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Downloaded by CORNELL UNIV on August 11, 2016 | http://pubs.acs.org Publication Date: June 1, 1973 | doi: 10.1021/ba-1973-0121.ch015

H. J. BOSMANS, E. TAMBUYZER, J. PAENHUYS, L. YLEN and J. VANCLUYSEN Afdeling Bodemgenese en -mineralogie, Landbouwinstituut, K. U. L., Kard. Mercierlaan 92, B3030 Heverlee, Belgium

Starting from soluble silicates and aluminates, the crystallizationfieldsof 14 zeolites were explored in the Na O-Al O -SiO H O, K O-Al O -SiO -H O, and K O-Na O-Al O -SiO H O systems at 90°C. On dilution, thefieldof hydroxysodalite gives way to that of zeolite A and X or Y, and thefieldof zeolite K-F to that of zeolites K-G (or H) and Q (or K-I). With time, zeolite K-F is replaced by the more stable zeolites J (90 m % H O) or K-G and Q (97 mole % H O). In the mixed-base system withK O/(K O+ Na O) = 0.5 at 90°C and 90 mole % water, a new zeolite was synthesized. This zeolite, V, has a primitive cubic unit cell with a = 9.415 A, and a chemical content of Na K Si Al O ·12H O. 2

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lthough zeolite crystallization in the systems Na 0-Al 03-Si02-H20 (1-7) and K2O-AI2O3-S1O2-H2O (8-16) at relatively low temperatures (ca. 100°C) has been thoroughly explored, a more systematic investigation of the influence of reaction time and water content in the mixtures could explain some ambiguities about which zeolites may be obtained under certain exact conditions. A detailed exploration of the mixed-base system K20-Na20-Al 03-Si02-H 0 seemed worthwhile since this system was studied only for high Si0 /Al 0 ratios (10, 16). In addition, there is confusion about the designation of some identical crystalline phases. This study is limited to the use of soluble reactants to ensure formation in the mixed gels of homogeneous solids which may crystallize with higher reproducibility into zeolites (16). Low temperatures (90 and 100°C) are used to obtain a variety of easily formed but relatively unstable zeolites (17, 7). With time, they may convert into other, more stable zeolites. 2

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Experimental The reagents used were sodium silicate, sodium aluminate, and potassium silicate (all from H & W). Potassium aluminate solution was pre179 Meier and Uytterhoeven; Molecular Sieves Advances in Chemistry; American Chemical Society: Washington, DC, 1973.

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p a r e d b y d i s s o l v i n g A l ( M e r c k A . R . ) i n a n 8N K O H s o l u t i o n . S o l u t i o n s of 14ΛΓ K O H a n d 16iV N a O H were also p r e p a r e d . *These reagents were a n a l y z e d for exact N a 0 or K 0 a n d S i 0 or A 1 0 content, a n d t h e i r H 0 c o n t e n t w a s also t a k e n i n t o a c c o u n t i n c a l c u l a t i n g t h e a m o u n t of H 0 r e q u i r e d t o o b t a i n the expected mole % of H 0 i n t h e r e s u l t a n t m i x t u r e s . F o r syntheses w i t h m i x e d bases, i f t h e K 0 / ( K 0 + N a 0 ) r a t i o w a s 0.75, t h e o n l y A l source was K A 1 0 ; i f t h e r a t i o was 0.50, t h e o n l y S i source was K S i 0 , a n d if t h e r a t i o was 0.25, the m i x t u r e s l o w i n base were s y n thesised w i t h K S i 0 a n d N a A 1 0 , a n d t h e m i x t u r e s h i g h i n base w i t h N a S i 0 a n d K A 1 0 . H o w e v e r , some t r i a l experiments i n the s y s t e m w i t h K 0 / ( K 0 + N a 0 ) = 0.50 showed t h a t n o significant differences i n t h e synthesis p r o d u c t s r e s u l t e d b y m i x i n g solutions of N a A 1 0 a n d K S i 0 r a t h e r t h a n s o l u t i o n s of K A 1 0 a n d N a 2 S i 0 i n p r e p a r i n g a m i x e d gel w i t h t h e same c o m p o s i t i o n . T h e silicate a n d a l u m i n a t e solutions or solids were w e i g h e d , a n d t h e other reagents were a d d e d f r o m b u r e t s a n d m i x e d i n plastic containers (polypropylene). T h e d i r e c t l y closed containers were t h e n a r r a n g e d i n a n o v e n , a n d t h e r m o s t a t e d a t t h e desired t e m p e r a t u r e . W i t h reactions of a d a y or longer, no p r e h e a t i n g of t h e reagents was done. H o w e v e r , for t h e k i n e t i c s t u d y , t h e reagents were p r e h e a t e d i n separate containers before m i x i n g a t t h e s t a r t of t h e experiments. T h e s e gel m i x t u r e s were h o m o g e n i z e d t w i c e a d a y t o ensure a sufficiently homogeneous m i x t u r e b u t w i t h o u t d i s t u r b i n g the c r y s t a l l i z i n g process i n the gel too f r e quently. A f t e r t h e r e q u i r e d r e a c t i o n t i m e , t h e gel m i x t u r e s were cooled, c e n t r i fugea, a n d w a s h e d three t i m e s w i t h m o r e t h a n a t e n f o l d q u a n t i t y of d i s t i l l e d w a t e r . A f t e r d r y i n g a t 105°C, t h e p r o d u c t s were p o w d e r e d i f neces s a r y . X - r a y d i f f r a c t i o n d i a g r a m s were recorded ( C u Κ α r a d i a t i o n ) , a n d t h e phases present were i d e n t i f i e d b y c o m p a r i n g t h e i r d i f f r a c t i o n peaks w i t h p u b l i s h e d d v a l u e s or w i t h those of s t a n d a r d zeolite d i f f r a c t i o n d i a g r a m s . T h e q u a n t i t y of each species w a s e s t i m a t e d w i t h i n 5 % f r o m r e l a t i v e p e a k h e i g h t s c o m p a r e d w i t h the best of t h e i r k i n d , w h i c h were also selected for a more detailed crystallographic examination. 2

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Results and Discussion T o represent t h e c r y s t a l l i z a t i o n fields of systems w i t h o n l y one base, M 0 - A l 0 - S i 0 - H 0 , at a constant mole % of w a t e r a n d at constant t e m p e r a t u r e , t h e f a m i l i a r t r i a n g u l a r d i a g r a m w i t h t h e constituents of t h e gel m i x t u r e s M 0 , S i 0 , a n d A 1 0 expressed i n mole % was used. O n l y t h e left p a r t of these t r i a n g u l a r d i a g r a m s is s h o w n (Figures 1-5), because s t a r t i n g w i t h soluble a l u m i n a t e s , o n l y m i x t u r e s w i t h A 1 0 / ( M 0 + A 1 0 ) lower t h a n 5 0 % m a y be p r e p a r e d . A separate t r i a n g u l a r d i a g r a m is presented for v a r y i n g d i l u t i o n s (i.e., mole % of H 0 ) or temperatures, a n d consecu tive reaction times. 2

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A d i l u t i o n of 90 mole % H 0 corresponds t o 6 0 - 7 3 w t % i n H 0 , d e p e n d i n g o n t h e r e l a t i v e concentrations of the other components, a n d 97 mole % i n H 0 corresponds t o 8 5 - 9 0 w t % i n H 0 . T o p l o t the results of t h e mixed-base s y s t e m N a 2 0 - K 0 - A l 0 - S i 0 - H 0 , we preferred t o use sections p a r a l l e l to the base i n a t r i g o n a l p r i s m , whose base plane is the 2

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Meier and Uytterhoeven; Molecular Sieves Advances in Chemistry; American Chemical Society: Washington, DC, 1973.

BOSMANS E T A L .

Zeolite Formation

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Figure 1. Zeolite syntheses in the system; KjD-AWs-SiOr-HtO. reaction time and dilution.


Effect of


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K0 2

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Figure 2.

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Al 0 2

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Zeolite syntheses in the system; KiO-AWz-SiOz-HiO. Effect of reaction time and dilution {cont'd) and of temperature.



Figure 3. Zeolite syntheses in the system; Na^O-AWz-SiO^-H^O. reaction time and dilution.


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Zeolite syntheses in the mixed-base system. Effect of reaction time and K2O/K2O + Na 0 ratio. 2


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BOSMANS ET A L .


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M 0 10 2

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Figure 5. Zeolite syntheses in the mixed-base system shown in Figure 4· Kinetics of formation of zeolites F W, and J. }


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t r i a n g u l a r d i a g r a m N a 0 - A l 0 3 - S i 0 2 , a n d whose u p p e r p l a n e is t h e d i a 2

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gram K 0 - A l 0 3 - S i 0 . 2

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N a 0 a n d K 0 i n t h e s y s t e m is stressed c o m p a r e d w i t h t h e more i n d e p e n d e n t 2

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a n d A 1 0 components. 2

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Sections w i t h K 0 / ( K 0 + N a 2 0 ) ratios of 2

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75, 50, a n d 2 5 % were explored after one d a y a n d after three d a y s a t 9 0 ° C a n d for 90 mole % H 0 . T h e c r y s t a l l i n e phases, o b t a i n e d i n t h e s o l i d 2

separated f r o m t h e m i x t u r e , are designated b y l e t t e r s y m b o l s a n d are t a b u l a t e d i n T a b l e I w i t h t h e i r f u l l names, s y n o n y m s , a n d c r y s t a l l i n e p a r a m eters.

A c a p i t a l letter indicates t h a t more t h a n 5 0 % of t h i s phase was

p r o d u c e d a t t h a t g e l c o m p o s i t i o n p o i n t , a n d lower case l e t t e r i n d i c a t e s t h a t less t h a n 5 0 % of t h e phase w a s f o r m e d i n t h a t p o i n t .

If quantities


smaller t h a n 5 % were observed i n p o i n t s w i t h m a n y phases, these were o m i t t e d so as n o t t o o v e r c r o w d t h e figure w i t h s y m b o l s , o b s c u r i n g the m a i n features. T h e g r a d u a l extension w i t h t i m e of t h e c r y s t a l l i z a t i o n fields of each phase, s t a r t i n g f r o m some p r e f e r e n t i a l gel c o m p o s i t i o n p o i n t , confirms t h e s t r o n g influence of t h e r e l a t i v e c o n c e n t r a t i o n of t h e components i n t h e s y s t e m o n t h e c r y s t a l l i z a t i o n of a specific zeolite (16). C o m p a r i s o n of t h e same s y s t e m a t a n o t h e r d i l u t i o n shows generally t h a t a longer t i m e is needed for c o m p a r a b l e c r y s t a l g r o w t h , b u t also a specific r e t r e a t of t h e Table I. Name and Synonyms Hydroxysodalite (C, D) Hydroxycancrinite Zeolites X and Y

Symbol Used

Identified Zeolites Crystallographic Parameters, A

S

Cubic, body-centered, a = 8.95

C X

Hexagonal, a = 12.63, c = 5.14 Cubic, face-centered, faujasite type, a = 24.69-25.19 (variable) Cubic, primitive, a = 12.28 (24.56) Pseudocubic, gismondine type, a = 10.03 Tetragonal, a = 10.12, c = 9.84

Zeolite A (ZK-4) Zeolite N a P l (B, Pc, B l ) Zeolite NaP2 (Pt, B2) Zeolite R

A Ρ

Zeolite K - F (F)

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Zeolite K - M (W, M) Zeolite L Zeolite J Zeolite Q (impure) (K-I) Zeolite K - G (H = impure) Zeolite V Amorphous gel

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L J Q H V

Hexagonal, chabazite-like, Na-form, a = 13.7, c = 15.3 Tetragonal, body-centered, a = 9.82, c = 13.09 Pseudocubic, body-centered, a = 20.06 (variable) Hexagonal, a = 18.34, c = 7.53 Tetragonal, a = 9.53, c = 9.79 Hexagonal, a = 13.48, c = 13.38 Hexagonal, chabazite-like(?), Κ form, a = 13.75, c = 15.40 (variable) Cubic primitive, a = 9.43

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d o m a i n of a zeolite phase t o t h e advantage of another is observed. This is the case for h y d r o x y s o d a l i t e (S) y i e l d i n g t o zeolite X or Y a n d even m o r e to A ( F i g u r e 3 a, b , d ) , s h o w n p r e v i o u s l y b y B r e c k a n d F l a n i g e n (7). T h i s effect is also observed f o r zeolites K - F ( F ) a n d J y i e l d i n g t o zeolites K - G ( H ) a n d K - I (Q) o n d i l u t i o n ( F i g u r e 1 a - d ; F i g u r e 2 a , c). The relation ship of zeolite H t o K - G a n d K - I has been explained b y B a r r e r , C o l e , a n d S t i c h e r (18). If, however, a zeolite gives w a y t o t h e f o r m a t i o n of another zeolite, after some t i m e at t h e same c o m p o s i t i o n p o i n t a n d t h e same d i l u t i o n , t h i s reflects a higher s t a b i l i t y of t h e n e w l y f o r m e d phase, f o l l o w i n g O s t w a l d ' s r u l e . W e observe t h i s i n t h e t r a n s f o r m a t i o n of zeolites A a n d X (or Y ) i n t o N a P l ( P ) o r N a P 2 ( T ) ( F i g u r e 3a, c ) , as s h o w n also b y R e g i s et al. (6). I n the K2O-AI2O3-S1O2-H2O s y s t e m , the t r a n s f o r m a t i o n of F i n t o J is s h o w n ( w i t h 90 mole % of w a t e r a t 9 0 ° C a n d faster a t 1 0 0 ° C ) (Figures l a , b a n d 2a, b , d ; see also F i g u r e 5e) a n d of F i n t o H or Q ( w i t h 97 mole % d i l u t i o n ) (Figures l e , d a n d 2c). I n t h e mixed-base s y s t e m w i t h a K 0 / ( K 0 + N a 0 ) r a t i o of 0.5, w e observe the t r a n s f o r m a t i o n of t h e u n k n o w n zeolite designated as V i n t o F a n d W , s h o w i n g zeolite V t o be a r e l a t i v e l y unstable phase. I n t h e mixed-base systems, t h e influence of t h e larger b u t less h y d r a t e d c a t i o n K + extends f a r t h e r t h a n t h a t of N a . T h i s is s h o w n b y t h e fact t h a t the m e e t i n g zone of the c r y s t a l l i z a t i o n fields of t y p i c a l Κ zeolites w i t h t y p i c a l N a zeolites is s i t u a t e d near a l o w K 0 / ( K 0 + N a 0 ) r a t i o (0.25). T h e g r o w t h of zeolites F a n d W is s h o w n i n F i g u r e 5c, d . T h e f o r m a t i o n a n d t r a n s f o r m a t i o n of zeolite F i n t o zeolite J is s h o w n i n F i g u r e 5e. 2

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Tabic II. d, A 9.438 6.554 5.451 4.750 4.220 3.852 3.339 3.115

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X - R a y Powder Pattern of Zeolite V (N = ft + fc + I ) Rel. Int. d, A Ν Ν Rel. Int. 2

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1.00 0.07 0.10 0.03 0.45 0.07 0.06 0.23

0.50 0.56 0.05 0.03 0.15 0.18 0.08 0.06

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2.983 2.844 2.612 2.359 2.289 2.224 1.886 1.618

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T h e u n k n o w n zeolite, designated V , shows a few s t r o n g x - r a y diffrac t i o n peaks (Table I I ) . I n d e x i n g y i e l d e d a p r i m i t i v e cubic cell w i t h a = 9.415 ± 0.030 A ( b y e x t r a p o l a t i o n ) . F r o m c h e m i c a l analysis after e q u i l i b r a t i o n of t h e sample a t 3 2 % r e l a t i v e h u m i d i t y , the f o l l o w i n g c o m p o s i t i o n c o u l d be c a l c u l a t e d : 0.54 K 0 , 0.50 N a a O , 1.00 A 1 0 , 2.24 S i 0 , 3.80 H 0. T h e measured d e n s i t y was 2.191 grams c m . F r o m t h e n u m b e r of c h e m i c a l formulas, Ζ = 1.5, g o i n g i n t o t h e u n i t cell, t h e f o l l o w i n g i d e a l ized c h e m i c a l content was d e r i v e d : Na3K3Al6Si6024-12H 0. T h e base 2

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exchange capacity (BEC) is 5.48 mequiv/gram. Although a superstructure might not be excluded, the similarity of some d values with those of ZK-5 (19) because of the nearly halved α parameter could not be extended as a result of many missing x-ray diffraction peaks and their difference in in tensity. The crystals in the samples of zeolite V, viewed with the scanning electron microscope, looked like dies, i.e., cubes with rounded edges. Acknowledgment We thank W. J . Mortier for help and suggestions.


Literature Cited 1. Barrer, R. M., White, E. A. D., J. Chem. Soc. (1952) 1561. 2. Breck, D. W., Eversole, W. G., Milton, R. M., Reed, F. B., Thomas, T. L., J. Amer. Chem. Soc. (1956) 78, 5693. 3. Milton, R. M., U.S. patent 2,882,243 (1959). 4. Milton, R. M., U.S. patent 2,882,244 (1959). 5. Breck, D. W., U.S. patent 3,130,007 (1964). 6. Regis, A. J., Sand, L. B., Calmon, C., Gilwood, M. E., J. Phys. Chem. (1960) 64, 1567. 7. Breck, D. W., Flanigen, E. M., Mol. Siev. Conf. London (1967) 47. 8. Barrer, R. M., Baynham, J. W., J. Chem. Soc. (1956) 2882. 9. Milton, R. M., U.S. patent 2,996,358 (1961). 10. Milton, R. M., U.S. patent 3,012,853 (1961). 11. Breck, D. W., Acara, Ν. Α., U.S. patent 3,011,869 (1961). 12. Breck, D. W., Acara, Ν. Α., U.S. patent 2,991,151 (1961). 13. Milton, R. M., U.S. patent 3,010,789 (1961). 14. Breck, D. W., Acara, Ν. Α., U.S. patent 3,216,789 (1965). 15. Ovsepyan, M . E., Zhdanov, S. P., Izv. Akad. Nauk., Ser. Khim. (1965) 1, 11. 16.

Zhdanov, S. P., ADVAN. CHEM. SER. (1971) 101, 20.

17. Zhdanov, S. P., Mol. Siev., Soc. Chem.Ind.,London (1968) 62. 18. Barrer, R. M., Cole, J. F., Sticher, H., J. Chem. Soc. (1968) 2475. 19. Kerr, G. T. Science (1963) 140, 1412. RECEIVED November 30, 1972.


Zeolite Formation in the System K

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