Mechanisms of Product Yield and Selectivity Control with Octane

Chapter 6

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and

Mechanisms of Product Yield Selectivity Control with Octane Catalysts John S. Magee and James W. Moore

Katalistiks International, Inc., 4810 Seton Drive, Baltimore, MD 21215 It i s generally accepted that aluminum deficient structures derived from type Y zeolite alter the extent of hydrogen transfer reactions which ordinarily favor the formation of paraffins and aromatics at the expense of olefins and naphthenes. This octane reducing reaction i s controlled principally by the silica/alumina ratio of the zeolite and i t s rare earth content(1). Furthermore, i t has been shown that octane enhancement occurs through the formation of different molecular types in "light" (b.p. 100 to 260°F) versus "heavy" (bp 260 to 430°F) gasoline(1,2,3). Enhanced olefins in l i g h t gasoline account for substantial increases in that fraction's research octane number (RON C) while higher concentrations of aromatics, for the most part, improve both RON C and MON C in the heavy gasoline. The present paper describes studies done which show that the ratio of hydrogen transfer to cracking (H-t/C) controls product quality and the presence of non-selective but c a t a l y t i c a l l y active debris is a contributor to losses in product y i e l d . W o r l d - w i d e t h e r e i s a p p r o x i m a t e l y 1000 t o n s o f fluid c r a c k i n g c a t a l y s t manufactured each day. Of t h i s , a b o u t 35% c o n t a i n s s o m e f o r m o f a l u m i n u m deficient z e o l i t e Y , one whose S i 0 / A l 0 r a t i o exceeds 5.5:1, and whose p e r f o r m a n c e i s g e n e r a l l y c h a r a c t e r i z e d by enhanced o l e f i n f o r m a t i o n and h i g h e r g a s o l i n e research and motor o c t a n e number. The aluminum deficient 2

c

2

3

0097-6156/88/0375-0087$06.00/0 1988 A m e r i c a n C h e m i c a l Society

Occelli; Fluid Catalytic Cracking ACS Symposium Series; American Chemical Society: Washington, DC, 1988.

88

F L U I D C A T A L Y T I C C R A C K I N G : R O L E IN M O D E R N R E F I N I N G

z e o l i t e s used i n these "octane c a t a l y s t s " are either chemical or hydrothermal derivatives of type Y z e o l i t e . L e s s commonly u s e d a r e shape s e l e c t i v e m o l e c u l a r sieves (SSMS), which a r e d e r i v a t i v e s o f t h e p e n t a s i l s . In all, some 8 0 - 1 0 0 t o n s o f a l u m i n u m d e f i c i e n t z e o l i t e are produced each day f o r consumption i n octane catalysts w i t h a m u c h s m a l l e r a m o u n t o f SSMS b e i n g manufactured for this purpose. V i r t u a l l y a l l the growth i n t h i s area has occurred s i n c e 1976 when t h e f i r s t o c t a n e c a t a l y s t s w e r e commercially used(4). I n s p i r i n g t h i s use has been legislation dictating reductions in lead tetraethyl usage t o the p o i n t were i t s usage i s a p p r o a c h i n g zero i n b o t h the U n i t e d S t a t e s and Europe. The r e s u l t i n g octane d e b i t from the c a t c r a c k e r s c o n t r i b u t i o n t o the gasoline pool i s the p r i n c i p a l reason for the outstanding growth i n usage of octane catalysts.

Experimental Catalysts F i v e c a t a l y s t s were used i n t h i s s t u d y : the predomin a t e l y g a s o l i n e o r i e n t e d f u l l r a r e e a r t h exchanged EKZ4, a p a r t i a l l y r a r e e a r t h exchanged gasoline/octane c a t a l y s t S I G M A 3 0 0 , a c o m p e t i t i v e USY c o n t a i n i n g o c t a n e c a t a l y s t "COM-USY", K a t a l i s t i k s ' p r i n c i p a l octane b a r r e l c a t a l y s t , ALPHA 5 0 0 , a n d maximum o c t a n e catalyst BETA 500. P h y s i c a l and c h e m i c a l p r o p e r t i e s are g i v e n i n Table I

Catalyst

Pretreatment

Prior to evaluation i n the p i l o t plant, a l l catalysts were steam t r e a t e d t o s i m u l a t e e q u i l i b r i u m a c t i v i t y . The steaming procedure used f o r a l l c a t a l y s t s i s as follows: c a l c i n a t i o n i n n i t r o g e n atmosphere a t 1350°F f o r t h r e e h o u r s f o l l o w e d b y s t e a m i n g a t 1 3 5 0 ° F f o r 14 h o u r s w i t h 100% s t e a m a t a t m o s p h e r i c pressure. Catalyst

Evaluation

P i l o t p l a n t t e s t s w e r e made i n a c y c l i c f i x e d fluidized bed u n i t over a range of c o n d i t i o n s . Catalyst-to-oil r a t i o w a s v a r i e d f r o m 3 t o 5 a n d WHSV w a s v a r i e d from 32 t o 5 3 , i n v e r s e l y . The r e a c t o r temperature w a s h e l d a t 975°F f o r t h e c r a c k i n g and steam s t r i p p i n g c y c l e s , and a t 1200°F f o r t h e r e g e n e r a t i o n c y c l e s . After regeneration, c a r b o n o n c a t a l y s t was e f f e c t i v e l y zero.


6.

MAGEE AND M O O R E

Table

Catalyst:

Surface

I.

EKZ-4

Catalyst

SIGMA-

Properties

"COM-" TTSY

ALPHA-

BETA500

Area,

mVg Pore Volume, cc/g A1 0 , wt% Re 0 , wt% Unit Cell Size, a A 2

89

Yield and Selectivity with Octane Catalysts

182

157

238

283

278

0.30

0.31

0.32

0.36

0.35

27.8

37.3

34.8

33.9

32.7

4.40

1.46

0.50

-2

+

n

C

paraffin

r a

H2m-6

aromatic

N a p h t h e n e C r a n k i n g (Γ) 3C H multi-ring naphthene x n

2 m

^

CmH olefin 2 l n

+

2C H naphthene m

2 m

A n a p h t h e n e i s u s e d f o r t h i s i l l u s t r a t i o n a s we b e l i e v e t h a t t h e r e l a t i v e amounts o f naphthene c r a c k i n g versus hydrogen t r a n s f e r c o n t r o l product d i s t r i b u t i o n s and q u a l i t i e s i n octane c a t a l y s t systems. Gasoline s e l e c t i v e c a t a l y s t s favor hydrogen t r a n s f e r reactions with these molecules with consequent formation o f coke. Results of the present study at constant c o n v e r s i o n a r e shown i n T a b l e s I I I A a n d Β a n d I V A a n d B . As s u g g e s t e d by t h e model e q u a t i o n s i l l u s t r a t e d above a n d l a t e r i n t h e t e x t we h a v e p o s t u l a t e d t h a t t h e o v e r a l l hydrogen t r a n s f e r r e a c t i o n forming aromatics and p a r a f f i n s from o l e f i n s and naphthenes c a n be controlled at various intermediate stages. These stages a r e c h a r a c t e r i z e d by high o l e f i n y i e l d s i n t h e light gasoline with progressively higher concentrations


6.

M A G E E AND M O O R E


Table

II.

Feedstock

Gravity, °API Sulfur, wt% Basic Nitrogen, PPM Ramsbottom Carbon, wt% Aniline Point, °F Pour Point, °F Molecular weight UOP Κ Factor Distillation (D1160), °F 5 vol% 10 v o l % 30 v o l % 50 v o l % 70 v o l % 90 v o l % Hydrocarbon Type Distribution Aromatics (C ) Naphthenes (C ) Paraffins (d>) A

N

Properties

Paraffinie Feed »P» 25.9 0.53 920 0.59 196 95 391 12.0

Aromatic Feed "A" 21.2 1.19 596 2.17 186 85 390 11.7

658 700 782 845 918 1030

615 667 762 825 898 1014

14.4 26.5 59.1

20.3 26.9 52.8


91


92

o f heavy g a s o l i n e a r o m a t i c s formed as the S i 0 / A l 0 of the steam d e a c t i v a t e d c a t a l y s t i n c r e a s e s . A l s o observed are measurable q u a l i t y changes i n both the l i g h t cycle (LCO) and heavy c y c l e o i l (HCO). In the case of "non-octane" c a t a l y s t s , H-transfer i s v i r t u a l l y complete and t h e r e a c t i o n proceeds (through aromatic condensation reactions) to coke. Clear cut control of these stages is related to both the silica/alumina r a t i o of the zeolite present (its u n i t c e l l s i z e ) and t h e amount o f s i l i c a / a l u m i n a debris present. Silica/alumina debris is a reaction product from the hydrothermal d e c o m p o s i t i o n o f the zeolite p r e s e n t and i s c a l c u l a t e d by assuming t h a t A 1 0 is the p r i n c i p a l degradation product i n the conversion from low t o h i g h s i l i c a / a l u m i n a r a t i o . Both s t a r t i n g and p r o d u c t r a t i o s are d e r i v e d from u n i t c e l l measurements according to the Breck/Flanigen c o r r e l a t i o n (5a). An a p p r o x i m a t i o n o f t h e e x t e n t o f hydrogen t r a n s f e r r e a c t i o n s o c c u r r i n g compared t o c r a c k i n g r e a c t i o n s and t h e n e t e f f e c t on p r o d u c t d i s t r i b u t i o n c a n be i n i t i a l l y seen by a c o n s i d e r a t i o n o f t h e zeolite properties of the catalysts tested i n the present study: 2

2

ratalysfr! a

Q

A

/

Si0 Al 0 2

2

3

2

F1K7.-4

SIGMA100

24.50

24.33

8.8

22

12 28

>

% "Debris" > 3

#

Tetrahedral sites/U.C. > 4

x

2

3

4

> > > >

Competitive Calculated. Calculated. Calculated.

3

3

ALPHA5UQ

BETA-

24.27

24.26

24.27

40

46

40

25

29

25

18

10

3.4

2.4

3.4

USY-Containing Reference 5a. Reference 5b. Reference 6.

"COM TTSV"*)

2

Octane

Catalyst

Chemical analysis ( T a b l e I) shows t h a t E K Z - 4 , SIGMA 300 a n d " C O M - U S Y " c o n t a i n r a r e e a r t h b u t " C O M USY" f a l l s i n the range a s s o c i a t e d with a high l e v e l of h y d r o g e n t r a n s f e r c o n t r o l (low H - t / C ) a l o n g w i t h ALPHA and BETA. D a t a show a l a r g e A l ( I V ) site separation f o r " C O M - U S Y " , A L P H A 500 a n d B E T A 500 b u t significantly different l e v e l s of c a t a l y t i c a l l y a c t i v e but nonselective "debris" from the d e - a l u m i n a t i o n o c c u r r i n g d u r i n g steam d e a c t i v a t i o n . One o f t h e p r i n c i p a l a d v a n t a g e s o f t h e ALPHA and BETA s y s t e m s i s t h e i r h i g h


6.


Table

III

A.

P i l o t P l a n t R e s u l t s a t 72 P a r a f f i n i e Feed, "P"

Catalyst:

EKZ-4

SIGMA-

"COM-" ITSY

Product PCT C

93


vol%

Conversion

ALPHAΒΩΩ

BETABOO

Yields,

Feed:

2

,

wt%

1.4

1.3

1.4

1.3

1.3

C

3

,

vol%

2.8

2.2

2.3

1.9

2.0

C

3

,

IC NC C

4

C

5

,

4

3.6

4.0

4.6

4.6

5.1

vol%

8.6

8.5

8.5

7.8

8.9

vol%

2.1

1.8

1.7

1.4

1.6

3.4

4.5

5.0

5.1

6.3

61.4

61.5

61.8

62.2

17.5

17.7

17.7

18.0

vol% ,

4

,

vol%

+

Gasoline,

vol%

61.0

LCO,

vol%

HCO,

vol%

12.0

10.5

10.3

10.3

10.0

Coke,

wt%

4.2

3.8

2.9

3.4

2.4

Light

Gasoline

Yield,

vol%

RON MON Heavy

37.5

36.7

37.1

37.5

37.0

83.8

85.0

87.5

87.2

89.3

78.7

78.4

79.5

79.6

79.8

Gasoline

Yield,

vol%

RON MON LCO

16.0

23.9

24.8

24.7

24.7

24.0

88.8

88.0

89.8

90.7

90.7

79.6

78.4

79.8

81.1

81.1

42

42

53

55

62

Aniline

Pt.,

°F

C Alkylate +Gasoline+LCO 4

83. 5

87.Ί

88.5

89.1


90.4


94

Table

III

B.

Pilot Plant Results Aromatic Feed,

Catalyst: Product Yields, PCT Feed: C - , wt% C -, vol% C -, vol% IC , vol% NC , vol% C =, v o l % C + Gasoline, vol% LCO, vol% HCO, vol% C o k e , wt% Light Gasoline Y i e l d , vol% MON MON 2

3

3

4

4

4

5

Heavy Gasoline Y i e l d , vol% RON MON C Alkylate

STGMA-,100

a t 72 "A"

vol%

AT.PHA-50Q

Conversion

BETA-50Q

2.9 2.4 5.2 7.6 1.7 5.2 58.0 18.2 9.8 7.1

1.9 2.1 5.8 7.1 1.4 5.9 58.2 18.6 9.4 6.5

2. 2. 5. 6. 1. 6. 58. 18. 9.3 6.5

34.5 86.2 80.1

34 88 80

35.1 88.6 80.7

23.5 89.3 80.6

24.0 91.7 82.3

23.0 92.4 83.2

85.6

87.4

88.Q

4

+ G a s o l i n e + T.CO


6.


Table

IV

A.

1

vol* IV

SIGMA-

"Com-"

1ΩΩ

Light Gasoline: Paraffins, vol% Olefins, vol% Naphthenes, vol% Aromatics, vol% Heavy Gasoline: Paraffins, vol% Olefins, vol% Naphthenes, vol% Aromatics,

Table

G a s o l i n e PONA s a t 72 V o l % P a r a f f i n i c Feed, "P"

EKZ-4

CATALYST:

B.

Conversion

BETA-

ALPHA-

τι.ςγ

500

500

68.9

64.8

61.5

60.6

58.0

12.7

18.1

21.0

21.6

24.2

10.0

11.3

10.1

11.5

10.8

8.4

5.8

7.4

6.3

7.0

32.5

33.1

30.3

29.4

29.6

2.0

4.4

3.4

6.4

4.3

8.3

8.5

9.5

9.0

8.8

57. 2

54.0

55.2

57.3

56.8

G a s o l i n e PONA s a t Aromatic Feed,

CATALYST: Light Gasoline: Paraffins, vol% Olefins, vol% Naphthenes, vol% Aromatics, vol% Heavy G a s o l i n e Paraffins, vol% Olefins, vol% Naphethenes, vol%

Aromatics. vol %

95


1

72 V o l % "A"

Conversion

STGMA-300

ΑΤ.ΡΗΑ-5ΩΩ

BETA—

62.8 17.7 12.6 6.9

58.7 22.0 12.3 7.0

57.0 25.1 11.4 6.5

24.8 1.9 6.9 66.4

23.5 1.9 6.4

23.5 1.9 6.2 68.4

fi8.2


96

FLUID CATALYTIC CRACKING: R O L E IN M O D E R N REFINING

hydrothermal s t a b i l i t y which retards debris formation (7) . We e x p e c t w i d e s i t e s e p a r a t i o n (2-3 Al/U.C.) to increase c r a c k i n g versus hydrogen t r a n s f e r i f hydrogen transfer i s a two-center r e a c t i o n l i k e coke formation (8) . Thus more o l e f i n i c p r o d u c t s a r e p r e d i c t e d a n d higher molecular weight products (more g a s o l i n e plus distillate) due t o t h e wide s i t e separation (greater d i s t a n c e s between l o c a t i o n s l i k e l y t o form carbonium ions on t h e carbon chain) i s expected. Finally, the more d e b r i s p r e s e n t i n t h e s e s t r u c t u r e s t h e more n o n s e l e c t i v e cracking of higher molecular weight products w i l l o c c u r i n z e o l i t e s c o n t a i n i n g t h e l e a s t amount o f Al(IV) sites. T h u s , we w o u l d e x p e c t A L P H A , B E T A a n d COM-USY t o h a v e s i m i l a r l y s e p a r a t e d s i t e s b u t t h a t C O M USY w o u l d show p o o r e r g a s o l i n e a n d c o k e s e l e c t i v i t y d u e t o t h e p r e s e n c e o f more " d e b r i s " . A possible mechanism b y w h i c h t h i s n o n - s e l e c t i v e c r a c k i n g may o c c u r i s s h o w n i n F i g u r e 1. H e r e c e t a n e when c r a c k e d i n t h e a b s e n c e of debris, i s i n f l u e n c e d by only one a c t i v e s i t e i n t h e z e o l i t e supercage and high molecular weight products are formed*. D e b r i s , when p r e s e n t , effectively reduces s i t e s e p a r a t i o n and would be expected t o i n f l u e n c e cracking s e l e c t i v i t y by reducing product molecular weight ("overcracking"). Based on c a t a l y s t s and which should r selectivities product yields

the active site properties of the test on t h e proposed product selectivities e s u l t , t h e observed and predicated are virtually identical. F o r example change as follows:

Olefins EKZ4 < S I G - 3 0 0 Coke S e l e c t i v i t y < — C A l k y . + G+D < Gasoline** < LCO < HCO C r a c k . A b i l i t y < 4

< COM-USY Ditto Ditto Ditto Ditto Ditto

< A-500

> > > >

Our d a t a i n d i c a t e d t h a t LCO y i e l d a n d q u a l i t y i m p r o v e d d u e t o t h e c o n v e r s i o n o f HCO m o l e c u l e s (apparently m u l t i - r i n g naphthenes) b y BETA a n d , t o a

* Though ~3 sites/supercage are present (see page 4) literature reports suggest that only one of three sites is actually catalytically active (9). ** ALPHA 500 in this instance actually equilibrated at a slightly lover a (higher Si0 /Al 0 ) than BETA 500. By virtue of this ve may expect somewhat higher gasoline selectivity for ALPHA and the observed product distributions of BETA and Com-USY to be similar. 0

2

2

3


MAGEE AND M O O R E


-25ASU Union Carbide

1

C7 + Cg

LZ-210 (e.g.

ALPHA

and

Su

BETA)

Hydrothermal S t r u c t u r e with A m o r p h o u s Debris

2C + 2C 5

US-Y (e.g.

Figure

"Com-USY")

1.

Stylized cracking

s i t e placement e f f e c t s on i n high S i / A l zeolites.

cetane


3


98

l e s s e r d e g r e e ALPHA and COM-USY, High l e v e l s of hydrogen t r a n s f e r probably convert these molecules coke. Reaction

i n t o t h e LCO r a n g e . (as i n E K Z - 4 ) would i n t o a r o m a t i c s and

MP.nhani.gm.g

P o s s i b l e r e a c t i o n mechanisms which e x p l a i n t h e t r e n d s observed i n product q u a l i t i e s are i l l u s t r a t e d i n r e a c t i o n s (1) (4) below.

R 5 C . . 3

=

+

R ^

Q

f

R

->

5C 4

8

R

1)

+ "{oXof

R e a c t i o n s (1) a n d (2) illustrate classical complete hydrogen t r a n s f e r between l i g h t o l e f i n s and L C O a n d HCO r a n g e n a p h t h e n e s . R e a c t i o n (3) represents condensation of polynuclear aromatics to coke, while r e a c t i o n (4) represents z e o l i t i c c r a c k i n g of heavy gas o i l n a p h t h e n e s i n t o LCO r a n g e n a p h t h e n e s a n d gasoline range o l e f i n s . Based upon these model r e a c t i o n s , the expected effect of decreasing the rate (amount) of h y d r o g e n t r a n s f e r r e l a t i v e t o c r a c k i n g would be t h e following: 1. 2. 3. 4. 5.

higher gasoline octanes with a s i g n i f i c a n t l y higher olefin content, more o l e f i n i c LPG, w i t h t h e p o t e n t i a l for increased alkylate production, l e s s a r o m a t i c LCO, w h i c h would be o b s e r v e d by a higher aniline point, lower coke y i e l d , h i g h e r LCO y i e l d a t c o n s t a n t c o n v e r s i o n .

Observed

experimental

results

are

as

follows:



6.

Paraffinic


99

Feed

T h e PONA r e s u l t s a t c o n s t a n t c o n v e r s i o n (72 v o l % ) in t h e s e r i e s f r o m EKZ4 t o BETA 500 show g a s o l i n e olefin c o n t e n t i n c r e a s e d from 8.6 p e r c e n t t o 16.4 p e r c e n t , p a r a f f i n c o n t e n t decreased from 54.7 p e r c e n t t o 46.8 p e r c e n t , and naphthene and a r o m a t i c s c o n t e n t s remained constant. R e s e a r c h o c t a n e i n c r e a s e d 4.2 numbers while m o t o r o c t a n e i n c r e a s e d 1.2 n u m b e r s . The a r o m a t i c s c o n t e n t o f t h e LCO a s m e a s u r e d b y t h e a n i l i n e p o i n t d e c r e a s e d w i t h t h e a n i l i n e p o i n t i n c r e a s i n g f r o m 42 t o 62. LCO y i e l d i n c r e a s e d f r o m 1 6 . 0 v o l u m e p e r c e n t t o 18.0 volume p e r c e n t , w h i l e the coke y i e l d decreased d r a m a t i c a l l y from 4.2 p e r c e n t t o 2.4 percent.

Aromatic Feed T h e PONA r e s u l t s a t c o n s t a n t c o n v e r s i o n (72 v o l % ) for t h e s e r i e s SIGMA 3 0 0 , ALPHA 500 a n d B E T A 500 show g a s o l i n e o l e f i n c o n t e n t i n c r e a s e d from 11.3 p e r c e n t t o 15.9 p e r c e n t , p a r a f f i n c o n t e n t decreased from 47.4 percent t o 43.7 percent, naphthene content decreased from 10.3 p e r c e n t t o 9.3 p e r c e n t and a r o m a t i c s c o n t e n t remained constant. Research octane increased 2.6 n u m b e r s w h i l e m o t o r o c t a n e i n c r e a s e d 1.4 n u m b e r s . The LCO y i e l d i n c r e a s e d 0 . 5 v o l u m e p e r c e n t w h i l e t h e c o k e y i e l d decreased from 7.1 weight p e r c e n t t o 6.5 weight percent.

Summary 1. C o n t r o l o f t h e e x t e n t r e s p e c t t o c r a c k i n g (the selectivity. As • • • • • • •

of hydrogen t r a n s f e r with H-t/C ratio) controls catalyst

the r a t i o decreases: Gasoline s e l e c t i v i t y increases for the paraffinic feed Coke s e l e c t i v i t y improves f o r b o t h feeds LCO s e l e c t i v i t y i n c r e a s e s f o r b o t h feeds LCO q u a l i t y i m p r o v e s f o r t h e p a r a f f i n i c feed HCO c o n v e r s i o n i m p r o v e s f o r b o t h feeds O l e f i n c o n c e n t r a t i o n i n l i g h t and heavy gasoline increases for both feeds Aromatic content i n heavy g a s o l i n e increases for the aromatic feed

2. R e d u c t i o n o f t h e amount o f n o n - s e l e c t i v e amorphous d e b r i s p r e s e n t as i n ALPHA and BETA c a t a l y s t s increases a l k y l a t e , g a s o l i n e and d i s t i l l a t e y i e l d s and reduces t h e amount o f s e c o n d a r y r e a c t i o n s l e a d i n g t o c o k e and wet gas. 3. A s i d e from t h e i r d e m o n s t r a t e d o c t a n e e n h a n c i n g c a p a b i l i t i e s , c a t a l y s t s w i t h low H - t / C r a t i o s can e f f e c t i v e l y l o w e r t h e y i e l d o f HCO w h i l e i m p r o v i n g b o t h q u a l i t y and q u a n t i t y o f LCO.


100


REFERENCES 1. 2. 3. 4. 5a. 5b. 6. 7. 8. 9.

Pine, L . A . , Maher, P.J. Wachter, W.A., J.Catal., 1984, 85, 466-476 (1984). Magee, J . S . , Cormier, W.E. , Woltermann, G.M., QGJ, 5/27/85. Andreasson, H.U., Upson, L . L . , Katalistiks 6th Annual Symposium, May 22-23, 1985. Magee, J . S . , Ritter, R.E. "Symposium on Octane in the 1980s," ACS Div. Petro. Chem., Sept. 0-15, (1978) Breck, D.W., "Zeolite Molecular Sieves", Robert E. Krieger Pub. Co., 1984, p94 S.D. Griffith, Private Communication, 1/30/87. John, J . R . , DeCanio, S . J . , Fritz, P.O., Lunsford, J . H . , J.P. Chem, 1986, 90, 4847-4851. Rabo, J . A . , Pellet, R . J . , Magee, J . S . , Mitchell, B.R., Moore, J.W., Magnusson, J.E., Upson, L.L., NPRA AM 86-30, 3/23/86. Bremer, H . , Wendlandt, K.P., Vogt, F . , Becker, Κ., Weber, Μ., Acta Phys. Chem. 1985, 31, 376. Beyerlein, R.A. McVicker, G.G., Yacullo, L.M., Ziemiak, J.J., 1986, Symposium on Fund. Chem. Promoters and Poisons in Hetero. Cat., 190-197.

RECEIVED March 30, 1988


Mechanisms of Product Yield and Selectivity Control with Octane

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