Synthesis and Characterization of a New Zeolite of the Offretite Type

2 Synthesis and Characterization of a New Zeolite of the Offretite Type

Downloaded by CORNELL UNIV on May 27, 2017 | http://pubs.acs.org Publication Date: May 17, 1983 | doi: 10.1021/bk-1983-0218.ch002

MARIO L. OCCELLI and ANTHONY J. PERROTTA Gulf Research & Development Company, Pittsburgh, PA 15230

An offretite-type zeolite has been synthesized in the tetramethyl ammonium-rubidium-alumina-silica-water system by the formation of a hydrogel of composition: Al O :13.OSiO :2.ORb O:9.0[(CH ) N] O;38OH O. Crystallization of the gel at temperatures ranging from 95° to 150°C gives crystals characterized by a BET surface area of 380-420 m /g and pore volume of 0.22-0.24 c c / g . The typical crystals composition (on a dry basis) i s A l O : 8.7SiO :0.9Rb O:0.085[(CH ) N] O. Crystal properties have been investigated by X-ray powder d i f fraction, sorption, SEM, infrared, and thermal analysis techniques. (Rb,TMA) offretite appear to crystallize as irregular, rod-like particles having a high thermal s t a b i l i t y . The oxidative decomposition of TMA cations occur i n two steps at 300°C and 430°C causing the appearance of new bands i n the OH stretching region. Rb-Offretite sorbs 1.17 mmole/g n-butane and 1.01 mmole/g isobutane at 26°C. Their isosteric heat of sorption are nearly independent of coverage and amount of 9.2 and 12.3 Kcal/mole, respectively. 2

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Offretite i s a hexagonal zeolite first discovered by Professor Gonnard(1) i n 1890 i n amygdaloidal basalt at Mount Semiouse near Montbreson, France. Offretite has been synthesized by Rubin,(2) and Aiello and Barrer(3) from aluminosilicate hydrogels i n a TMA (tetramethylammonium)-KOH-NaOH mixed base system. Aiello and Barrer noted that this zeolite can be grown from gels i n the presence of KOH-TMAOH but not in the presence of NaOH-TMAOH. Sand(4) has shown that offretite can be synthesized without TMA-OH from NaOH-KOH solutions. The synthesis of offre0097-6156/83/0218-0021$06.00/0 © 1983 American Chemical Society Stucky and Dwyer; Intrazeolite Chemistry ACS Symposium Series; American Chemical Society: Washington, DC, 1983.

22

INTRAZEOLITE CHEMISTRY

t i t e c r y s t a l s always included the presence of potassium ions u n t i l f a i r l y r e c e n t l y when B a r r e r and S i e b e r ( 5 ) were a b l e t o c r y s t a l l i z e t h i s z e o l i t e from a LiOH-CsOH-TMAOH c o n t a i n i n g h y d r o g e l . I t i s the purpose of t h i s paper t o d e s c r i b e the PerrottaC6) s y n t h e s i s o f a new z e o l i t e of the o f f r e t i t e type c r y s t a l l i z e d from a potassium f r e e , a l u m i n o s l l l c a t e hydrogel i n the presence o f Rb-TMA i o n s .


Experimental Rubidium-TMA-offretite was c r y s t a l l i z e d from a A ^ C ^ - S i C ^ Rb20-TMA0H % g e l prepared from h i g h p u r i t y grade r e a c t a n t s . Aqueous rubidium c h l o r i d e , aluminum n i t r a t e , and TMA hydroxide s o l u t i o n s were mixed i n a polypropylene beaker and then s l o w l y added t o s i l i c a s o l (LUDOX-AS, 30 wt% SIO2) under vigorous s t i r r ing. The r e s u l t i n g hydrogel was allowed t o c o l d age a t room temperature f o r a few hours and then heated at ~95°C i n a sealed polypropylene b o t t l e . The c r y s t a l s were separated from the mother l i q u o r by c e n t r i f u g a t l o n and subsequently washed w i t h d i s t i l l e d water. The c r y s t a l s were d r i e d i n a i r a t 100°C. (H,Rb) o f f r e t i t e was obtained by i o n exchanging the c a l c i n e d , TMA-free, R b - o f f r e t i t e w i t h a 0.5 M NH4NO3 s o l u t i o n at 80°C f o r 4 h r . Decomposition of the ammonium ions was obtained by h e a t i n g i n a i r at 550 °C overnight. A Perkin-Elmer TGS-2 thermogravimetric system(7) was used to measure s o r p t i o n of normal and isobutane. A schematic diagram of t h i s apparatus i s shown i n Figure 1. The microbalance, equipped w i t h temperature c o n t r o l and weight monitor u n i t s , i s connected t o a vacuum system which c o n s i s t s of an o i l d i f f u s i o n pump backed up by a mechanical pump. Included i n the vacuum system are a Texas Instrument P r e c i s i o n q u a r t z s p i r a l pressure gauge, a Veeco i o n i z a t i o n - t y p e vacuum gauge and a V a r i a n VacIon pump. The c a t a l y s t sample was suspended i n a sample pan surrounded by a platinum resistance heater. This heater was c o n t r o l l e d by a temperature program c o n t r o l l e r . The weight change of the c a t a l y s t d u r i n g an experiment was monitored by a balance c o n t r o l u n i t and recorded by a Hewlett-Packard 7100B r e c o r d e r . The s e n s i t i v i t y of the microbalance was ±0.2 ug. DSC and TGA measurements were c a r r i e d out using a DuPont 1090 thermal a n a l y z e r using h i g h p u r i t y n i t r o g e n o r oxygen as purge gases and h e a t i n g rates of 10°C/min. The thermal s t a b i l i t y of the c r y s t a l s was i n v e s t i g a t e d by observing c r y s t a l l i n i t y changes i n samples heated i n the temperature range of 540-980°C f o r a period of 4 h r . A l l powder d i f f r a c t i o n measurements were obtained on a P i c k e r X-ray d i f f r a c t o m e t e r at a scan r a t e of l°/min using monochromatic Cu-K r a d i a t i o n . Scanning e l e c t r o n micrographs (SEM) where taken w i t h a JEOL (Japanese E l e c t r o n O p t i c Laboratory) JSM-35 instrument. I n f r a r e d measurements were performed on a NICOLET 7000 FTIR spectrometer. Samples were pressed a t 1500 atm i n t o t h i n , s e l f supporting wafers approximately 1 i n . i n diameter. The wafers were then mounted i n an o p t i c a l c e l l . The IR c e l l

Stucky and Dwyer; Intrazeolite Chemistry ACS Symposium Series; American Chemical Society: Washington, DC, 1983.


RECORDER

CHART

STRIP

JIT

CON TROL

B A U tNCE

CONTR OLLER

HEA TER

PROGRAMMER

TEMPERATURE

UNIT

1.

S5(

V4

—

)S7

V6

system

S6

MECHANIC PUMP

PUMP

J-D

PUMP

VACION

• f l

DIFFUSION

S3

V4

GAUGE

V3

VACUUM GAUGE

PRESSURE

S2

Thermogravimetric

Figure

HEATER

1

r-J

MICROBALANCE

SI


INTRAZEOLITE

24

CHEMISTRY

allowed the thermal treatment i n vacuo of the samples up t o 400 °C and d i r e c t l o a d i n g o f p y r i d i n e vapors. P y r i d i n e was sorbed a t 25°C on wafers that had been heat treated a t 400°C f o r 1 h r . Degassing o f the p y r i d i n e loaded samples was conducted a t d i f f e r ent temperatures and t h e i r IR s p e c t r a recorded. R e s u l t s and D i s c u s s i o n Synthesis The i n v e s t i g a t i o n of the A l ^ : S i 0 : R b 0 : ( [ C ^ ] ^ N) 0:H 0 system has shown the e x i s t e n c e of three d i f f e r e n t crys-^ t a l l l n e phases. Representative s y n t h e s i s data i s shown i n Table I . A l l phases were formed below 120°C and obtained i n a 5-30 day c r y s t a l l i z a t i o n p e r i o d . At low TMAOH and s i l i c a concent r a t i o n ( S i 0 / A l 0 * TMAOH/AI0O3 * 5.0-6.0), the phase RbAlSi0 « 1.3H 0 c r y s t a l l i z e s from the hydrogel. By i n c r e a s i n g both the s i l i c a and the TMA i o n l e v e l s , a new z e o l i t e o f the o f f r e t i t e type appears. The x-ray d i f f r a c t o g r a m f o r t h i s phase i s shown i n Figure 2. A f u r t h e r Increase i n the s i l i c a , rubidium, and TMAOH content at constant alumina c o n c e n t r a t i o n r e s u l t s i n the c r y s t a l l i z a t i o n o f a new s o d a l i t e - t y p e phase. The X-ray data of t h i s new s o d a l i t e s p e c i e s , w i t h the computed c e l l constant, are given i n Table I I . The c e l l dimension o f 8.94 A i s s l i g h t l y l a r g e r than the c e l l dimension of h y d r o x y s o d a l i t e which i s 8.86 A.(8) Q u a l i t y (Rb,TMA) o f f r e t i t e c r y s t a l s are best obtained from hydrogels of composition: A1 0 :12.0SiO :2.0Rb O:9.0([CH ] N) 0: 360HoO. C r y s t a l s are c h a r a c t e r i z e d by a BET s u r f a c e area o f 360-420 m /g and a n i t r o g e n pore volume of 0.20-0.24 cc/g. The scanning e l e c t r o n micrographs i n F i g u r e 3, show that (Rb,TMA) o f f r e t i t e c r y s t a l l i z e s as r o d - l i k e p a r t i c l e s , i r r e g u l a r i n shape, f r e q u e n t l y c o n t a i n i n g v e r y s m a l l amounts o f an u n i d e n t i f i a b l e phase. As i n z e o l i t e A(9) and Y,(10) the c r y s t a l l i z a t i o n r e a c t i o n i s a u t o c a t a l y t i c i n nature• In f a c t a s m a l l a d d i t i o n o f seed c r y s t a l s y i e l d s a s i g n i f i c a n t decrease i n c r y s t a l l i z a t i o n time. As expected, f a s t e r c r y s t a l l i z a t i o n times can a l s o be induced by i n c r e a s i n g c r y s t a l l i z a t i o n temperature, (see Table I ) . T y p i c a l composition o f the c r y s t a l l i z a t i o n product i s : Al2.03:8.6 S i 0 : 0.95 Rb 0:0.071([CH3) N) 0. The h i g h S i 0 / A l 0 r a t i o observed (8.0 < S i O n / A l 0 £ 9.1) may be r e s p o n s i b l e f o r the e x c e l l e n t thermal s t a b i l i t y e x i b i t e d by these c r y s t a l s . After calcination i n a i r a t 870 °C f o r 4 h r they r e t a i n e d ~80% o f t h e i r o r i g i n a l c r y s t a l l i n i t y (see F i g u r e 4 ) . A s i m i l a r l y prepared sample of (Na,K,TMA) o f f r e t i t e r e t a i n e d o n l y a 34% c r y s t a l l i n i t y when t r e a t e d i n a s i m i l a r manner• A i e l l o and B a r r e r ( 3 ) have shown that d u r i n g (Na,K,TMA) o f f r e t i t e c r y s t a l l i z a t i o n , an i n c r e a s e i n the K/(K+Na) r a t i o r e s u l t s i n an i n c r e a s e i n the s i l i c a l e v e l of the crystals. A l a r g e r c a t i o n l i k e rubidium may i n d i r e c t l y promote the higher S i 0 content e x h i b i t e d by t h i s R b - z e o l i t e of the o f f r e t i t e type because i t encourages the l e s s bulky S i t o isomorphously s u b s t i t u t e f o r the Rb -A10 ~ combination i n the o f f r e t i t e lattice. 2


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OCCELLI AND PERROTTA

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25

A New Offretite Type Zeolite

Table I THE AlgC^-SiOg-RbgCM [CH3l^N^ 0-H 0 SYSTEM 2

t Gel Composition

T(°C) Days Present

A l O : 5 . 0 SiO :2.0Rb O:5.5([CH ] N) O:250 H 0 2

3

2

2

Phases

3

4

2

2

»

r ,

5

3

2

2

3

4

2


2

3

2

2

3

4

2

3

2

2

3

4

9 0

2

9 0

Offretite Type

-

2

A l 0 : 1 3 . 0 SiO :2.0Rb O:9.0([CH ] N) O:360 H 0 2

2

2

A l O : 1 2 . 0 SiO :2.0Rb O:8.5([CH ] N) O:360 H 0

1

Offretite Type Type

7

2

90

11*

0 f f r e t i t e

Type

A l O : 1 3 . 0 SiO :2.0Rb O:9.0([CH ] N) O:360 H 0 2

3

2

2

3

4

2

2

120

4

A l O : 1 3 . 0 SiO :2.0Rb O:9.0([CH ] N) O:360 H 0 2

3

2

2

3

4

2

3

2

2

3

4

90 25

Offretite+ Sodalite

2

95 27

Sodalite+ Offretite

2

A l 0 : 1 6 . 5 Si0 :4.0Rb O:11.0([CH ] N) 0:510H O 2

*

3

2

2

3

4

Offretite Type

2

A l O : 1 4 . 0 SiO :2.0Rb O:9.0([CH ] N) O:380 H 0 2

$ -

RbAlSiO^ 1.3 H 0

A l O : 5 . 0 SiO :2.0Rb O:5.5([CH ] N) O:260 H 0 2

s

2

2

Seeded (1 g R b - o f f r e t i t e c r y s t a l s per 870 g of g e l , dry b a s i s ) .

Table I I X-RAY DATA FOR TMA-Rb SODALITE d (A) Observed

d (A) Calculated

hKl

6.33 4.46 3.66 3.15 2.82 2.58 2.23 2.10 1.90 1.75 1.63 1.58 1.54 1.49 1.45

6.32 4.47 3.65 3.16 2.83 2.58 2.235 2.108 1.898 1.753 1.631 1.580 1.533 1.490 1.451

110 200 211 220 310 222 400 330 332 501 521 440 530 442 532

d

Q

- 8.94 A


26



TMA-K-Na-OFFRETITE

w

\J

TMA-Rb-OFFRETITE

43

39

36

31 "

27 1 20

23 19 1 . i (DEGREES)

15 i

jJ 11 i_

Figure 2. X-Ray dlffractograms for (Rb,TMA) offretite and (Na,K,TMA) offretite.





Figure 3. Scanning e l e c t r o n micrographs f o r (Rb,TMA)

offretite



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INTRAZEOLITE

540

650

760

870

CHEMISTRY

980

A C T I V A T I O N TEMPERATURE ( ° C ) Figure 4 . The thermal s t a b i l i t y o f (Rb» TMA) ( s o l i d l i n e ) and (Na, K» TMA) (broken l i n e ) o f f r e t i t e c r y s t a l s . The c r y s t a l l i n i t y o f the samples d r i e d a t 250 ° C / 4 hrs was a r b i t r a r i l y taken as 100%.



2.


A

New Offretite Type Zeolite

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Thermal A n a l y s i s The DTA p r o f i l e f o r (Rb,TMA) o f f r e t i t e i n Figure 5 shows the e x i s t a n c e o f three w e l l defined peaks r e p r e s e n t i n g dehydration and decompositions o f TMA c a t i o n s . The endot h e l i a l dehydration i s e s s e n t i a l l y completed at 220°C. The o x i d a t i v e decomposition of TMA ions occurs i n two steps a t 330 and 435°C r e s p e c t i v e l y . The exchangeable TMA ions i n the l a r g e , main channels are probably decomposed at the lower temperature and the nonexchangeable TMA i o n s , entrapped i n the g m e l i n l t e cages, decompose a t the higher temperature .(11) The thermogravimetric curve i n F i g u r e 6 c o r r e l a t e s w e l l w i t h the DTA p r o f i l e i n Figure 5 and shows that sorbed and z e o l i t i c water c o n t r i b u t e a 13.0 wt% l o s s . The weight l o s s between 220 and 500°C i s due t o the breakdown o f i n t r a c r y s t a l l i n e TMA i o n s . The remaining weight change (1.2 wt%) represents the dehydroxylation o f the OH-groups generated d u r i n g the thermal decomposition of the TMA i o n s . The t o t a l weight l o s s was 3.64 mg. When heating was conducted i n oxygen, an a d d i t i o n a l 2.1 wt% was l o s t due t o the o x i d a t i o n of otherwise r e s i d u a l carbon deposits. S o r p t i o n Measurements S o r p t i o n isotherms f o r normal and isobutane were obtained on a sample of R b - o f f r e t i t e which had been c a l c i n e d i n a i r at 550°C o v e r n i g h t . The curves i n Figures 7 and 8, together w i t h the Clausius-Clapeyron equation, were used t o measure i s o s t e r i c heats o f s o r p t i o n . At a coverage o f ~0.4 mmoles/g, AH • 7.47 Kcal/mole f o r n-butane. By i n c r e a s i n g the sorbate l o a d i n g t o 0.79 mmoles/g the heat of s o r p t i o n i n creased s l i g h t l y ( t o 8.5 kcal/mole) i n d i c a t i n g the l a c k of p r e f e r e n t i a l s o r p t i o n centers i n R b - o f f r e t i t e c r y s t a l s . For Isobutane the AH was 10.2 kcal/mole. At 26°C (P/Po s 0.4) the e q u i l i b r i u m l o a d i n g f o r n-butane i s 1.17 mmoles/g. This l o a d i n g does not d i f f e r g r e a t l y from the isobutane e q u i l i b r i u m c a p a c i t y (1.01 mmoles/g) suggesting that these R b - o f f r e t i t e c r y s t a l s are probably f r e e from s a l t o c c l u s i o n and/or s t a c k i n g f a u l t s . Infrared Analysis As described by Wu et a l . ( 1 1 ) TMA decomp o s i t i o n i n o f f r e t i t e c r y s t a l s can be followed by observing t h e decrease i n I n t e n s i t y w i t h temperature of the TMA i o n bands and by the concomitant appearance o f new bands i n the OH s t r e t c h i n g region (see Figures 9 and 10). The IR spectra of (Rb,TMA) o f f r e t i t e a t d i f f e r e n t temperatures i s shown i n Figure 9. The band a t 3741 cm i s due t o t e r m i n a l Si-OH groups. The appearance of a new band a t 3615 cm" i s due t o OH groups generated during TMA decomposition a t 400°C. The p r o t i c nature of these hydroxyls was confirmed by t h e i r i n t e r a c t i o n w i t h p y r i d i n e (see F i g u r e 11). I n the p y r i d i n e loaded sample, the band at 3615 cm disappears w h i l e new a d s o r p t i o n bands due t o chemisorbed p y r i d i n e are generated i n the 1400-1650 cm"" r e g i o n (see Figure 12). Upon heating i n vacuo at 400°C f o r 1 h r , these new bands disappear and t h e band a t 3615 cm"" i s r e s t o r e d (see Figures 11 and 12). The s p e c t r a given i n F i g u r e 9 Includes the s p e c t r a o f a (Rb-TMA) o f f r e t i t e sample 1

1

1


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1

-j 100

i 200

i 300

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r


i

i 400

1 500

1 600

TEMPERATURE, C (CHROMEL/ALUMEL)

Figure 5. DTA p r o f i l e f o r (RbJMA) o f f r e t i t e and (Na,K,TMA) o f f r e t i t e i n oxygen. Sample weight: 9.8 mg. Heating r a t e : 10 °C/min. Oxygen flow r a t e : 55 CC/min.



Figure 6. Thermograms of(Rb,TMA) o f f r e t i t e c r y s t a l s i n oxygen and n i t r o g e n . Sample weight: 15.15 mg. Heating r a t e 10 °C/min. Gas flow r a t e : 180 CC/min.


H-*

Ν §

!

>

H H

§

m

D

>

ο M r r

Ο Ο

Stucky and Dwyer; Intrazeolite Chemistry ACS Symposium Series; American Chemical Society: Washington, DC, 1983. 80

90 PRESSURE (TORR)

Figure 7. N o r m a l butane sorption isotherms on Rb offretite.

70


100

H

g S3

m

S

W

H

W Ο f

% H

to


0

I

I 10

I 30

I 40

1

i 50

1

i 60

1

i 70 PRESSURE

1

Figure 8. Isobutane sorption isotherms on Rb offretite.

I 20

T

1

j 80 (TORR)


| 90

1

I 100

1

to

CHEMISTRY


INTRAZEOLITE

I 3900

i

' 3700

•

' 3500

i

1 3300

1—

*

,

3100

WAVENUMBERSfcm" ) 1

Rgure 9. Infrared absorption bands i n the OH-Stretching region f o r (Rb,TMA) o f f r e t i t e heated i n vacuo a t 100(a), 200(b), and 400 ° C ( c ) . The spectra of (H,Rb) o f f r e t i t e i s shown f o r comparison purposes




o z z 52 z o


00 ct


INTRAZEOLITE

CHEMISTRY


36

i 3800

I

I

3600

I l 3400 WAVENUMBERS (cm ) i

J 3200

i

- 1

Figure 11. Infrared spectra of R b - o f f r e t i t e before and a f t e r room temperature s o r p t i o n of p y r i d i n e . Outgassing temperatures: (a) 100, (b) 200, (c) 400 °C. Curve (d) r e f e r s to the R b - o f f r e t i t e c r y s t a l s used


I 3000



37


2.

_i 1700

i

i

i

I

1600

1500

1400

1300

1

WAVENUMBERSCcnT ) Figure 12. V a r i a t i o n o f IR band i n t e n s i t y o f chemisorbed p y r i d i n e . Outgassing temperatures: (b)100 °C (c)400 ° C . Curve (a) r e f e r s to the c a l c i n e d R b - o f f r e t i t e c r y s t a l s used.


38

INTRAZEOLITE

CHEMISTRY

which has been c a l c i n e d at 550°C o v e r n i g h t , NH^ exchanged, oven d r i e d , and then heated i n a i r a t 500°C f o r 4 h r . This s p e c t r a shows that bv r e p l a c i n g Rb ions w i t h protons, new bands at 3650 and 3560 cm"" appear w h i l e the Si-OH band remains f a i r l y constant at 3741 cm . The a c i d i c s t r e n g t h of these bands i s evident by t h e i r strong i n t e r a c t i o n w i t h p y r i d i n e which i s mostly r e t a i n e d even a f t e r desorbing i n vacuo at 400°C f o r 1 h r (see Figure 13).


1

z

—i 1700

i t — 1600 1500 W A V E N U M B E R S {cm" )

i — 1400

1

Figure 13. Infrared spectra o f (H,Rb) o f f r e t i t e before and a f t e r room temperature s o r p t i o n o f p y r i d i n e . Outgassing temperatures: (b) 25, (c) 100, and (d) 400 °C. Curve (a) r e f e r s to the (HRb) o f f r e t i t e c r y s t a l s used


2.



39

The s p e c t r a i n Figure 9 i s somewhat d i f f e r e n t from the spect r a of o f f r e t i t e c r y s t a l s synthesized i n the NaOH-KOH-TMAOH mixed base system, Wu e t a l . ( 1 1 ) , i n a d d i t i o n t o our observed band a t 3615 cm" , reported the appearance of a c i d i c bands a t 3690 and 3550 cm" • In c o n t r a s t , Mlrodatos et a l . ( 1 2 ) reported the appearance of only one, weakly a c i d i c band a t 3660 cm". The TMA content and the concentrations of d i f f e r e n t charge compensating c a t i o n s may be responsible f o r these d i f f e r e n c e s . Conclusions The i n v e s t i g a t i o n of the alumina-silica-rubidium-TMA system has shown the e x i s t e n c e of three d i f f e r e n t c r y s t a l l i n e phases. From an hydrogel o f composition A1 0 :13.0SiO :2.0Rb O:9.0 [(CH3)^N] O:360H O a new z e o l i t e of the o f f r e t i t e type c r y s t a l l i z e s as i r r e g u l a r , r o d - l i k e c r y s t a l s c h a r a c t e r i z e d by a BET surface area o f 380-420 cm /g, a pore volume o f 0.20-0.24 cc/g, and good thermal s t a b i l i t y to ~870°C. The o x i d a t i v e decomposition of TMA ions generates a c i d i c OH groups which v i b r a t e a t 3615 cm" . The exchange of rubidium w i t h ammonium ions produce new hydroxy Is which v i b r a t e a t 3650 and 3560 cm" . R b - o f f r e t i t e sorbs almost equimolar amounts of normal and isobutane suggesting that these c r y s t a l s a r e probably f r e e of s a l t o c c l u s i o n and/or s t a c k i n g faults.


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Acknowledgment s We thank Professor J . Hightower f o r a l l o w i n g the use of h i s thermogravimetric system; Dr. F. S. S. Hwu f o r many h e l p f u l suggestions during the s o r p t i o n measurements; and Dr. J . L e s t e r f o r a s s i s t a n c e w i t h IR data generation. Thanks are a l s o due t o Drs. H. E. Swift and J . V. Kennedy f o r c r i t i c a l l y reviewing t h i s manuscript. Literature Cited 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.

Gonnard, F. C. R. Acad. S c i . , 1890, 111, 1002. Rubin, M. K., German Patent No. P1806154.6, 1968. A i e l l o , R.; R. M. Barrer J. Chem. Soc. (A), 1970, 1470. Sand, L. B., U.S. Patent No. 4,093,699 1978. Barrer, R. M . ; Sieber, M. J. Chem. Soc. Dalton, 1977, 1020. Perrotta, A. J., U.S. Patent Pending. Hwu, S. S. F . , Ph.D Thesis, Rice University, Houston, Texas 1981. Breck, D. W. Zeolite Molecular Sieves, J. Wiley & Sons 1974. Kerr, G. T. J. Phys. Chem., 1966, 70, 1047. McDaniel, C. V . ; Mather, P. K., U.S. Patent No. 3,808,326 1974. Wu, E. L . ; White, T. E . , J r . ; Venuto, P. B., J. Catalysis 1971 21, 384. Mirodatos, C . ; Abou-Kais, A . ; Vedrine, J. C . ; Barthomeuf, D. J. Chim. Phys., 1978, 57.

RECEIVED November 16,

1982


Synthesis and Characterization of a New Zeolite of the Offretite Type

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