Alumina activated with anhydrous hydrogen fluoride as a dealkylation catalyst for aromatic
hydrocarbons
by Emil O Kindschy
A THESIS Submitted to the Graduate Committee in partial fulfillment of the requirements for the
degree of Master of Science in Chemical Engineering
Montana State University
© Copyright by Emil O Kindschy (1948)
Abstract:
The purpose of this investigation was to evaluate anhydrous hydrogen fluoride activated alumina as a
dealkylation catalyst for aromatic hydrocarbons.
Toluene, ethyl benzene, xylenes, isopropyl benzene, diethyl, benzenes, monoamyl benzene, diamyl
benzene, and triamyl benzene Were the aromatic hydrocarbons investigated.
The average run charged about 600 cc. of aromatic hydrocarbon over 900 cc. of catalyst at a space
velocity of approximately 0.5 volume per volume of catalyst per hour, and at atmospheric pressure.
The temperature that yielded the most dealkylated and the least alkylated products was found for
xylene and monoamyl benzene and this temperature used throughout the balance of the investigation.
Runs were made using alumina unactivated with anhydrous hydrogen fluoride to obtain a standard of
comparison for those runs with hydrogen fluoride treated alumina.
All the aromatic hydrocarbons used except toluene were successfully dealkylated. Isopropyl benzene
and the amyl benzenes were, dealkylated practically quantitatively. Alkylation took place with the
xylenes and ethyl benzene.
Benzene was found to be the ultimate dealkylation product of every aromatic hydrocarbon with two or
more carbon atoms in every branch chain, while toluene was the ultimate dealkylation product of any
aromatic hydrocarbon that contained only one carbon atom in any of its branch chains.
The data obtained also showed that as the temperature increased, other conditions being held constant,
dealkylation increased and alkylation decreased. 'All aromatic dealkylation products were the result of
carbon-carbon fission at the benzene ring. ALUMIMA a c t i v a t e d ,w i t h a n h y d r o u s h y d r o g e n f l u o r i d e
AS A DEALKYLATION CATALYST FOR AROMATIC
HYDROCARBONS
by
EMIL 0, KIMDSCEY
A THESIS
Submitted to the Graduate Committee
in
,
partial fulfillment of the requirements
for tNe degree of
Master of Science in Chemical Engineering
at
Montana State College
Approved?
Bozeman? Montana
August, 1948
A/37/
2
TABLE OF CONTENTS
Page
4
Abstract
I Introduction........ .
.....................
II Equipment, Methods, and Materials. ............
A. Equipment . . . . . . . . o . . . . . . . . .
B. Methods.. . . . . . . . . . .......... . . .
C . Materials . . . . . . . . . . . . . . . . . .
III Sample Calculations. . . . . . .
5
8
8
12
17
..............
18
........
...
21
.'....
27
VI Acknowledgment . . . . . . . . . . . . . . . . .
28
VII Literature Cited and Consulted ................
29
VIII Appendix . . . . . . . . . . ..................
Table I. . . . . . . . . . . ..............
Dealkylation of Xylenes and Calculated Results
31
33
Table II . . . . . . . . . . . . . .............
Dealkylation of Mcnoamyl Benzene and Calculated
Results
34
Table III. . . . . . . . . . . . . . . . . . .
Dealkylation of Diamyl Benzene, Triamyl Benzene
and Calculated Results
35
Table IV . . . . . . . . . . . . ............
Dealkylation of Toluene, Diethyl Benzene, Iso­
propyl Benzene and Calculated Results
36
Table V . . . . . . . . . . . . . . . . . . .
Dealkylation of Ethyl Benzene and Calculated
Results
37
IV Results. . . . . . . . . . . . .
V Conclusions..........
Figure I . . . . . . . . . . . . . . . . . . .
Diagram of Reaction Apparatus
.
Figure 2 . . . . . . . . . . . . . . ..........
Distillation Curves for Runs 3 and 8 (Xylene)
38
39
10C835
3
Page
FigT2I*e 3 o o e ,o o o o o o o o o e o o o e o o o e
Distillation/ Curves for Runs 11 and 12 (Monoamyl
Benzene)
4"0
F i g l i r e
4" I
4
o
o
e
o
e
o
o
o
o
o
o
o
e
o
o
o
o
o
o
o
e
Distillation Curves for Runs 13 and 14 (Diamyl
Benzene)
F IgUre ^ ? o o o e e o o o e o e o » e o o e o o o e
Distillation Curves for Runs 15 and 16 (Triamyl
Benzene)
Figure 6 0 * 0 0 0 0 0 0 © - © o © © © * © © ©
Distillation Curve for Run 17 (Toluene)
42
* © * 43
Figure 7 ® ® « « ° ° ® * ° ° ° ® ° ° ° ° ® ° ® ® ®
Distillation Curves for Runs 18 and 19 (Diethyl
Benzene)
1-44
Figure 8 0 0 0 0 © ® ® * * ® * © * ® ® ® ® ® ® ® ®
Distillation Curves for Runs 20 and 21 (Isopropyl
Benzene)
4*5
Figure 9 ® ® ® ® ® ® ® ® * ° ° ® ® ® ® ® ® ® ® ® ®
Distillation Curves for Runs 22 and 25 (Ethyl
Benzene)
4*6
Figure 10© e © ® ® ® © ® ® ® ® ® ® ® * ® ® ® ® ® ®
Distillation Curves for Runs 22, 23, 24, and 25
(Ethyl Benzene)
4*7
X
•'V
I
4
ABSTRACT
The purpose of this investigation was to evaluate anhy­
drous hydrogen fluoride activated alumina as a dealkylation
catalyst for aromatic hydrocarbons.
Toluene, ethyl benzene, xylenes, isopropyl benzene,
diethyl, benzenes, monoamyl benzene, diamyl benzene, and
triamyl benzene Were the aromatic hydrocarbons investigated.
The average run charged about 600 ec. of aromatic hydro­
carbon ovdr 900 cc. of catalyst at a space velocity of ap­
proximately 0.5 volume per volume of catalyst per hour, .and
at atmospheric pressure. The temperature that yielded the
most dealkylated and the least alkylated products was found
for xylene and monoamyl benzene and this temperature used
throughout the balance of the investigation.
Runs were made using alumina unactivated with anhydrous
hydrogen fluoride to obtain a standard of comparison for
those runs with hydrogen fluoride treated alumina.
All the aromatic hydrocarbons used except toluene were
successfully dealkylated. Isopropyl benzene and the amyl
benzenes were, dealkylated practically quantitatively. Alky­
lation took place with the xylenes and ethyl benzene.
Benzene was found to be the ultimate dealkylation pro­
duct of every aromatic hydrocarbon with two or more carbon
atoms in every branch chain, while toluene was the ultimate
dealkylation product of any aromatic hydrocarbon that con­
tained only one carbon atom in any of its branch chains.
The data obtained also showed that as the temperature in­
creased, other conditions being held constant, dealkylation
increased and alkylation decreased. 'All aromatic dealkyla­
tion products were the result of carbon-carbon fission at the
benzene ring.
5
I
INTRODUCTION
The. purpose of this investigation is to evaluate hydrogen
fluoride activated alumina as a dealkylation catalyst for
aromatic hydrocarbons.
Hytirogen fluoride activated alumina was selected as a
catalyst because hydrogen fluoride has been used as a dealky­
lating as well as an alkylating catalyst for aromatic hydro­
carbons .. Brandt et al (2) used.liquid anhydrous hydrogen
fluoride as a catalyst in the dealkylation of xylenes to
toluene.
Their investigation also showed that trimethyl
benzene is formed concurrently by alkylation of the xylene.
Frey (5) dealkylated polyethyl benzenes in the pres'ence of an
excess of benzene and a catalyst of anhydrous liquid hydrogen
fluoride to form ethyl benzene.
Alumina impregnated with aqueous zinc chloride was used
v
to dealkylate xylenes and other polymethyl benzenes to toluene
and also polyethyl benzenes to ethyl benzene (14).
An alumina
and silica catalyst was used to dealkylate dialkyl benzenes
(9 ).
/
lattox (12) used a catalyst of alumina and other metal
j
,
oxides in the "dealkanation" of diethyl benzene to xylene.
That alkylation as well as dealkylation could take place
might be expected from previous uses of hydrogen fluoride as
an alkylating catalyst.
Frey (4)(5) alkylated benzene using
light olefins as the alkylating agents and substantially an­
hydrous liquid hydrogen fluoride as the catalyst.
1
Koch (8 )
/
6
alkylated the products of HKogasinn synthesis (hydrocarbons
from the Fischer-Tropsch process) in the presence of anhy­
drous hydrogen fluoride and converted them into high-octane
fuels similar to isooctane.. A number of other investigations
have reported hydrogen fluoride, to be an alkylating catalyst
(3), (10), (11), (13), (15)«
Alumina has been used as a catalyst in the alkylation of
aromatic hydrocarbons,
Ipatieff and Monroe (6) used oxides
of aluminum in the alkylation of benzene to toluene, and
alumina with magnesium CbxIoride was used to alkylate aromatic
hydrocarbons in another investigation (7)*
Bepduse of the alkylating effect of hydrogen fluoride
and alumina when used separately, part of this investigation
was concerned with the alkylation effect of the alumina when
activated with anhydrous hydrogen fluoride. This investiga«=
I
tion is primarily, however, a study of the dealkylation
reaction.
Data were not available In the literature on the dealky­
lation effect of alumina alone under the reaction conditions
employed in this investigation.
It was necessary, therefore,
to make severalr uns with alumina unactivated by hydrogen
fluoride in order to obtain a standard of comparison for
those runs with hydrogen fluoride treated alumina.
This study was not concerned with the determination of
the optimum conditions of space velocity apd pressure in the
7
dealkylation system.
All runs were conducted at essentially
atmospheric pressure and the liquid space velocity,was held
in the neighborhood of 0.5 vol. per vol. of catalyst per hour.
The optimum temperature at this pressure and space velocity,
however, was readily determined.
As it was not feasible to attempt the dealkylation of all
the known aromatic hydrocarbons, a representative group was
selected.
Toluene, xylenes, ethyl benzene, diethyl benzenes,
isopropyl benzene, monoamyl benzene, diamyl benzenes, and tri­
amyl benzenes were chosen to be the dealkylated reagents.
These compounds are all available commercially in a fairly
pure state and were, therefore, not subjected to further
purification.
The boiling temperature; of compounds used or formed in
this investigation were not corrected to standard pressure
since no precise method, is available to make this conversion.
The average barometric pressure during this study was approxi­
mately 635 mm. Hg.
8
II
EQUIPMENT, METHODS, AND MATERIALS
Ao Equipment
The equipment used in this investigation consisted of
the reaction system shown in Figure I, iron-constantan
thermocouples9 a potentiometer, a precision rectification
column, a graduated water-cooled receiver for the column, a
vacuum system, three glass stem mercury thermometers, a
Claisson type distillation flask with condenser, a ceramic
heater, a one liter distillation flask, a Harvard type triple
beam balance, a refractometer, and four autotransformers0
The reactor was made from a piece of three inch stand­
ard mild steel pipe 24 inches long„
Black pipe was used
instead of galvanized to avoid vaporization of the zinc at
the elevated temperatures of the reactions.
The pipe was
threaded at both ends with the bottom end capped and the top
end fitted with a flanged head for easy removal.
The thermo­
wells were made from pieces of 1/8 inch standard steel pipe
4-3/4 inches long and sealed at one end.
The lower thermo­
well was placed two inches from the bottom of the reactor.
The middle and upper thermowells were spaced at four inch
intervals above the lower one.
The catalyst bed extended
from just below the bottom thermowell to within 1/2 inch of
the top thermowell.
Holes, 13/32 inch in diameter, were
drilled in the reactor at these points and the thermowells,
when welded to the reactor wall, extends# into tbe qxact
9
center of the catalyst spac$.
The iron-eonstantan thermo­
couples were connected to a Brown potentiometer.
This poten­
tiometer was calibrated.in millivolts and could be used to
record temperatures up to 1200Gc,
The millivolt readings
were converted into (,degrees Gentifrade using a standard con­
version table for iron-constantan thermocouples with the
reference junction at G0C e
Two 3/8 inch low carbon steel rods were Welded onto the
reactor on the opposite side from the thermowells to act as
supports for the reactor chamber„
These rods were eleven in­
ches long o
i
The reactor was wrapped with asbestos: tape,
Over this
tape9 75 feet of niehrome wire with a resistance of I„079
ohms per foot was wound„
This winding drew 2,95 amperes from
a 220 volt autotrangforfeero The winding was covered with as­
bestos
tape and another resistance winding 33 feet long
placed over it„
The second winding was connected to a H G
volt auto^ransformer and drew about seven amperes.
This
second winding was covered with asbestos tape and then a one
inch layer of magnesia was placed over ali the windings and
tape,
The malleable iron caps at the top and bottom of the
reactor were drilled and tapped to take 1/2 inch short nipples,
»
The upper one was fitted with a 1/2 inch malleable iron cross
and reduced to 1/8 inch,while the bottom one was reduced
10
directly to 1/8 Inch6
Feed was admitted to the top of the reactor from a 1000
m l o graduated separatory funnel through a lerkle-Korff type
bellows pump operating on H O volt A 6 G« and connected to the
reactor by 1/8 inch copper tubing0
To the bottom outlet, a 1/8 inch flexible copper tube
was fitted.
The tube led to a glass bulb type water cooled
condenser 20 inches long.and a dry ice condenser connected in
series as shown in Figure I e
The gas meter following the dry ice trap was a three
liter "Precision M Wet Test Metere
The rectification column was constructed of three con­
centric glass tubes.
The innermost tube was 33 mm, inside
diameter and was packed with 1/8 inch Fenske stainless steel
helices,
A thermometer was fastened to the outside surface
of the inner tube about halfway between top and bottom.
The
second or middle tube was wrapped with nichrome resistance
wire which w a s .connected to a H O volt autotransformer to pro­
vide heat to the column.
a protector and insulator.
The third or outer tube served as
The column was 48 inches high and
-calibrated about 30 theoretical plates at total reflux.
The
top of the cjdlumn was fitted with an adjustable reflux head
with a cold finger condenser and a thermometer to record vapor
temperatures,
A graduated water-cooled receiver was attached
to the outlet from thg distilling head*
Z
11
The vacuum system used consisted of a C6neo Hegavac pump
connected through two surge tanks to the distillation system*
The pump, operated on 220 volts A,
C o ,
was capable of taking
the first surge tank down to about one ram. Hg, absolute*
The first surge tank connected to the second through a Sole­
noid valve.
This valve was controlled by a mercury switch
and an electronic relay to give the desired pressure upon the
system*
The second surge tank was connected to the distilla­
tion system with a tee to a mercury filled manometer.
For
the purpose of consistency in this investigation all vacuum
distillations were made at 85 mm, Hg, absolute*
The heater used for the distillation flask had a ceramic
base supporting niehrome coils in a concave depression in
which the distillation flask was placed.
These coils were
connected to a H O volt autotransformer*
The one liter distillation flask used was equipped with
a 35725 spherical joint*
The Abbe type Valentine refractometer was capable of
reading to six significant figures.
All refractive indices
were read at 20 ± Q 0I eC*
The autotransformers were Superior Electric Company
Powerstats, The H O volt powerstats had a voltage range of
0 to 135 volts and were fused at seven amperes.
The 220
volt powerstats.had a voltage range of 0 to 260 volts and
were fused at three amperes*
12
Bo
Io
Methods
Preparation of the catalysts
The reactor was filled with Berl saddles to a point
about 1/4 inch below the bottom thermocouple.
Nine hundred
CCo of Harshaw 1/8 inch activated alumina pellets were
placed in the reactor over the Berl saddles.
The reactor
was then completely filled with additional Berl saddles.
These saddles acted as a preheat section.
The manner of catalyst activation was similar to that
outlined,by Berg et al (I).
The catalyst was dried at 250GC.
for two hours after being placed in the reactor. After cool­
ing to room temperature 9 anhydrous hydrogen fluoride was
passed through for another hour with the catalyst at room
temperature. With the hydrogen fluoride still passing
through9 the temperature was increased to 400°C. in one hour.
The catalyst was then purged with nitrogen gas for about
fifteen minutes to sweep out the excess hydrogen fluoride.
During the catalyst activation, the excess hydrogen fluoride
was bubbled through kerosene and out a blow down line.
2.
Making the reaction runs :
The reactor was heated until the center thermocouple
gave a reading slightly below the desired temperature.
Dry
ice was placed in the dry ice trap using a liquid such as
acetone or ttTromexw to give a better cooling medium.
The
density of the aromatic hydrocarbon being used wa^ measured
I
13
"by weighing a 1000 cc„ sample on the Harvard triple beam bal­
ance,
A charge, usually about 700 cc,, was placed in the
separatory funnel and the pump started to fill completely all
connecting tubing -to the reactor.
If necessary, air was
swept from the reactor by using a fifteen minute nitrogen
purge.
After the reactor was completely purged of air, the
feed system was connected.
Readings from all three thermo­
couples, the gas meter, and the volume of feed in the separ­
atory funnel were noted before the run was started and con­
tinued at ten minute intervals throughout the duration of the
run.
Upon completion of the run, the reactor was purged of
all hydrocarbon vapors by passing nitrogen through for fifteen
minutes.
During this purge, the gas meter was taken out of
the system and all condensable hydrocarbons were retained in
the receiver.
The receiver was -placed in a refrigerator
maintained at -400C, to minimize evaporation of the reaction
product prior to distillation.
The same procedure was used
in runs with both activated and unactivated catalyst,
3,
Distillation of reaction products:
Each charge was placed in the distillation -flask with
about 100 grams of a suitable chaser.
The chasers used for
all runs ape tabulated in Tables 1-7,
Heat flows to the
column and distillation flask were adjusted by means of the
aubotransformers in such a manner as to allow the column to
flood and insure complete wetting of the packing.
The heat
14
-
flows were then reduced sufficiently to stop the flooding
and the column permitted to operate at total reflux for one
houro
After the column had attained equilibrium^the reflux
ratio was set at about 5/1 and overhead cuts taken.
During
this time a dry ice condenser was kept in series with the
water condenser to retain any light hydrocarbon vapors pas­
sing through the latter.
Vapor temperatures were t,aken at the beginning and end
of each cut.
The size of the cuts taken depended upon the
rate of increase of the vapor temperature.
When the breaks
or mid-fractions were reached, smaller cuts were taken better
to define the distillation curve.
Distillation was continued until all the charge was dis­
tilled or until atmospheric distillation had to be abandoned
in favor of vacuum distillation.
If vacuum distillation had
to be used, the charge was allowed to cool, the system placed
under vacuum, and distillation recommenced.
When vacuum distilling the products of the triamyl ben­
zene runs, a Glaisson type distilling flask was used instead
of the rectification column because of excessive foaming.
Refractive indices were taken whenever the rate of in­
crease of the vapor temperature.indicated that a plateau was
reached on the distillation curve„
4,
Catalyst burn-off and reactivations
As the catalyst was used, a deposit of carbonaceous
15
material was laid down upon the catalyst surface, reducing
its activity and necessitating periodic burn-offs«, The cata­
lyst was burned -off at the end of every third run when dealkylating materials such as the xylenes, toluene, or ethyl
benzene and at the end of every run when the reactant was
diethyl benzene, isopropyl benzene, monoamyl benzene, diamyl
benzene, and triamyl benzene»
Burning off was accomplished by passing air through the
reactor while maintaining the burn-off temperature below the
sintering point of the catalyst, about 600°C,
The burn off
was done immediately after the completion of the run before
the catalyst bed had time to cool*
The catalyst was reactivated after the burn-off whenever
hydrogen, fluoride was detected in appreciable amounts in
either the products from the reactor or in the exhaust gases
from the burn-off„ .Reactivation was accomplished by cooling
the catalyst to room temperature and treating as described
above„
5»
Plotting the data obtained from distillations
The data were plotted as vapor temperature vs. weight
per cent distilled.
Whenever the water condenser was incap­
able of condensing all the vapors, an allowance was made on
the distillation curves for the material retained in the dry
ice trap'.
This is indicated on the distillation curves when­
ever the first plotted point is not at the zero per cent
16
distilled abscissa.
Whenever vacuum distillations were made, the vapor temp­
eratures were plotted on the same scale as the atmospheric
distillation temperatures.
All data for yields and conversions were taken from
these distillation curves.
\
/
.:*•'*
17
C« Materials
No attempt was made to purify any of the reagents used.
Compound
Meta and Para Xylene
Grade
Analytical
Source
Mallinckrodt Chemical
Works
Ortho Xylene
Eastman Kodak Company
Toluene
Dow Chemical Company
Ethyl Benzene
Dow Chemical Company
Diethyl Benzene
Dow.Chemical Company
Isopropyl,Benzene
Dow Chemical, Company.
Amyl Benzene
Technical
Sharpies Chemical C o , ,
Diamyl Benzene
Technical
Sharpies Chemical Co,
Triamyl Benzene
Technical
Sharpies.ChemicaluCp,
nrletreidecane. „■ •
The Connecticut.;,Hard.
Rubber Company
Anhydrous Hydrogen Fluoride
The Matheson Company
Activated Alumina Pellets9 .
1/8 inch-..diameter
Harshaw Chemical Company
,
•
18
III
SAMPLE CALCULATIONS
The sample calculations of conversions and space velocity
were based on Run #15 using activated catalyst and triamyl
benzene as the reagent. This run was chosen because it
yielded the most complex reaction products.
In this run,
however, the conversions and the yields were the same.
There­
fore, the sample calculations of yields were based upon Run
#3 using activated catalyst and a meta and para xylene mixture.
A0
Determination of per cent liquid products
These data were taken from Figure 5» the distilla­
tion curve for the activated triamyl benzene run.
The division lines between compounds on this curve
were located at the arithemetic mean of the temp­
eratures of the adjacent plateaus.
The quantity
of the distillation charge between the zero per
cent distilled point and the first point on the dis­
tillation curve represents that fraction of the dis­
tillation charge which passed through the water con­
denser and was retained in the dry ice trap placed
in series with the column condenser.
This fraction
of the distillation charge contained
G^, and
. hydrocarbons.
530.2 gramss
Thus, for a distillation charge of
19
Crams
Weight Per Cent
118.0
22.3
Pentenes
88.5
16.7
Benzene
72.6
13.7
150.3
28.3
71.6
13.5
0.0
0.0
29.2
530.2
___ SjI
100.0
Compound
O g,
and C^
Amyl Benzene
Diamyl Benzene
Triamyl Benzene
Distillation Losses
Be
Calculation of per cent of theoretical yield
- converted per pass:
For benzenes
c 6h
Me w„
3^c 5h 11^3--- c 6h 6"^ 3 C5H10
288,50
78.11
3(70.13)
Based upon the amount of triamyl benzene
charged to the reactor, 689 gramss
Theor, Yield;
= 186 grams
no
Actual Conversion;
A
jj§t~ x
s 39»O^
In" like manner, it can be determined that:
Conversion, per cent
and
Amyl Benzene
42.3
Diamyl Benzene
13.7
Benzene
_32a0
95.0
20
Ce
Calculation of liquid space velocity?
In Run
#
1 5 760 Ce, of trlamyl benzene were charged
to the reactor in le75 hours.
Since the reactor
contained 900 ce. of catalyst, it was determined
that %
Space Velocity
De
Calculation of yields:
In Figure 2, charging xylene over activated catalyst,
60«5 per cent of the distillation charge was un­
reacted xylene.
Since the distillation charge was
400el grams,
(400 el)(0 ©605 ) s 242 grams of unconverted xylene e
From the original charge to the reactor, 431 grams,
431 - 242 - 189 grams of xylene were consumed
or held up by the reactor.
cent of the total charge.
This represents 43.9 per
The yield of toluene cal­
culated by the method given in these sample calcu­
lations was 16.0 per cent of the theoretical.
If
43.9 per cent of the xylene made 16.0 per cent of the
theoretical yield of toluene, then 100 per cent of
the xylene would make
- 36®4 per cent of theoretical
yield of toluene.
21
IV
RESULTS
Xyleness
Table I in the appendix tabulates the conditions and
results of the xylene runs«
Runs 1-4Jsrere made using a meta­
para xylene mixture as the reactor charge and the activated
catalysto
Run I 9 at 40I0O „9 produced neither alkylation nor
dealkylation products of xylene c
At 44©°C«,9 Run 2 9 the liquid
product from the reactor contained l8 o5 per cent trimethyl
benzene and 12 per cent toluene, while at 5l0°C«,, Run 3? the
yield of trimethyl benzene decreased to 16 per cent of the
liquid product and the yield of toluene increased to 15 per
cent of the liquid product»
In Run 4, the temperature was in­
creased to 5420C o and an analysis of the products showed only
13 per cent trimethyl benzene while the yield of toluene was
increased to 19„1 per cent of the product0 At 542°C„9 however,
an inspection of the.catalyst after the run showed that part
of the catalyst had sintered*
These results showed.that as the temperature increased,
the amounts of dealkylated products also increased, while the
amounts of alkylated products decreased*
Since this investi­
gation was primarily interested in the dealkylation reaction,
500°C o was chosen the optimum temperature for dealkylating
xylenes without sintering the catalyst.
The meta-parq xylene mixture was partially separated into
its components by freezing.
The para-rich xylene mixture gave
slightly lower yields than the mixture used in Runs 1-4, but
the yields of both.the alkylated and the dealkylated products
were considerably lower for the meta-rich xylene mixture 6
Run 7 9 made with ortho xylene on the activated catalyst,
gave essentially the same yield of toluene, 14*7 per cent of
the liquid product, as the meta-para xylene mixture but gave
a slightly higher alkylation to trimethyl benzene than did
the meta-para xylene mixture *
At 504°Co and essentially the same conditions of space
velocity and pressure, the unactivated catalyst was inactive
towards either the alkylation or the dealkylation reaction*
No benzene was detected in the dealkylation products of
any of the xylenes nor was- benzene detected when an attempt
was made to dealkylate toluene itself (Run 17)»
From the fact that alkylation did take place in these
runs, it was presumed that part of the toluene formed was al­
kylated back to xylene, while at the same time, some of the
trimethyl benzene formed by alkylation of xylene was dealkylated back to, xylene*
Traces of ortho xylene were detected in the.products of
the me tap-para xylene runs, Whether this was due to the isomerization effect of the catalyst, the alkylation of toluene
to ortho xylene, or the dealkylation of trimethyl benzene was
not determined*
23
lonoamyl Benzenes
At 427°C e? 75«5 per cent of the theoretical yield of
benzene was detected in the reaction products.
At 504°C.9
Run IG9 this conversion was increased to 84 per cent.
Run Il5
duplicated the results of Run 10 after the catalyst was burn­
ed off and reactivated.
The conditions and results of these
runs are tabulated in Table II.
Only 16«8 per cent of the
theoretical benzene was formed5 however 9 when monoamyl ben­
zene was passed over the unactiVated alumina catalyst at
503°0.
No appreciable amounts of alkylated products were de­
tected in any of the monoamyl benzene runs 9 nor were any
aromatic dealkylated products other than benzene found.
Diamyl Benzene and Triamyl Benzenes
Table III tabulates the conditions and results of the
dealkylation of diamyl benzene and triamyl benzene. At 4980C »
with the activated catalyst, diamyl benzene formed 63.3 per
cent of the theroetical yield of benzene, 26.4 per cent of
the theoretical yield of monoamyl benzene, and no unreacted
diamyl benzene.
Over the unactivated catalyst, however, at
the same conditions of temperature, pressure, and liquid
space.velocity, the reaction products contained no benzene
and 38.8 per cent of the theoretical monoamyl benzene.
Triamyl benzene with the activated catalyst at 499°C.
24
formed 39«0 per cent of the theoretical benzene9 42„3 per cent
monoamyl benzene9 13®7 per cent diamyl benzene9 and no un­
reacted triamyl benzene remained.
At 500oC e and with the un­
activated catalyst, only a trace of benzene or monoamyl benzene
was formed, but 41.1 per cent of the theoretical yield of dipamyl benzene was detected.
The presence of the intermediate products of the de­
alkylation of these polyamyl benzenes to benzene9 indicated
that the contact time was too short for the dealkylation re­
action to be complete.
A s -in the dealkylation of monoamyl benzene9 the polyamyl
benzenes did not form alkylation products9 nor did any dealky­
lation occur except at the benzene ring.
Toluene:
Table IV gives the conditions and results of the dealky­
lation of toluene, diethyl benzene, and isopropyl benzene.
The dealkylation of toluene, as mentioned previously,
formed no appreciable amount of benzene.
Even though no alky­
lation products of toluene were apparent, it cannot be stated
that alkylation of toluene would not take place with the
catalyst under the conditions used.
Since any alkylation
would depend upon a product of dealkylation for the alkylating
reagent, and since no dealkylation took place, no alkylation
of toluene could occur even though the catalyst was active
25
with respect to aIkylatione
Diethyl Benzene i
At 500°Co with the activated catalyst, 38.6 per cent of
the theoretical yield of 'ethyl benzene was formed by dealky­
lation of diethyl benzene.
No appreciable amounts of benzene
nor alkylated products of diethyl benzene were found.
The
unactivated catalyst was inactive towards diethyl benzene at
499gC .
Isopropyl Benzene;
Eighty-six per dent of the theoretical yield of benzene
was produced when isopropyl benzene wars passed over the act!-:
vated catalyst at 505°Co
At 500GC o, the unactivated catalyst
formed only 2,9 per cent of the theoretical amount of benzene.
In neither of these runs was any liquid reaction product
found other than benzene.
Ethyl Benzene s
Ethyl benzene was reacted under four different stages of
the catalyst cycle.
of these runs.
Table V shows the conditions and results
Run 22, made with activated catalyst, showed
that ethyl benzene formed 17,4 per cent of the theoretical
benzene and 4.9 per cent of the theoretical yield of diethyl
benzene,
Under the same conditions of temperature, pressure, and
26
space velocity, the activated catalyst, when fouled with car­
bon, was inactive for either alkylation or dealkylation.
This
is shown in the results of Run 23«
When the earboned catalyst was burned off, the conversion
to benzene was 7,2 per cent of theoretical and the conversion
to diethyl benzene was 4,6 per.cent.
This shows that the
catalyst had part of its former activity restored by the car­
bon burn-off but that it needed reactivation with anhydrous
hydrogen fluoride to recover all of its previous activity.
The unactivated alumina gave approximately the same results as
the earboned catalyst.
Figure 10 shows the distillation curves for the ethyl
benzene runs under all these conditions of the catalyst cycle.
It is important to note that for none of the hydrocarbons
used, was any liquid dealkylation product detected other than
those that resulted from cleavage at the benzene ring.
27
V
C OHGLUSIOJSfS
The following conclusions may be drawn concerning both
alkylation and dealkylation with the hydrogen fluoride acti­
vated alumina catalysts
I,
Benzene is the ultimate dealkylation product for
all aromatic hydrocarbons that contain two or more
carbon atoms in every branch chain,
2o
Toluene is unaffected by the catalyst under the
conditions used in this investigation and will
probably be the ultimate dealkylation product of
any aromatic hydrocarbon that contains only one
carbon atom in any of its branch chains,
3o
Pressure and space velocity being constant, dealky­
lation will increase as the temperature increases
and alkylation will decrease as the temperature
increases,
4.
The rate of dealkylation increases with the length
of the side chains on any aromatic hydrocarbon,
5o
Alkylation probably takes place whenever dealkylation
occurs but when the molecules are large, (diethyl
benzene or larger) the alkylated products are so
'readily dealkylated that none appear in the final
product,
6o
Dealkylation with this catalyst and at the conditions
used always takes place at thq benzene ring.
•Ss
28
VI
ACKNOWLEDGMENT
The amthor acknowledges with thanks the courtesy of the
Dow Chemical Company who furnished the toluene ? isopropyl
benzene ^ ethyl benzene9 and diethyl benzene used in this
investigation®
He also acknowledges with thanks the courtesy of the
Sharpies Chemical Company who furnished the mono-, di-, and
triamyl benzene used in this research®
29
TII
LITERATURE CITED AND CONSULTED
(1)
Berg 9 .Lo 3 Simmer 9 G 0 L 09 .and Montgomery9 Co W 09 (To
Gulf Research and Development Go*); U* S . Patent
2,397,639 (April 2, 1946)
(2)
Brandt 9 P 6 Lo 9 Lee 9 R 0 J» 9 Radford, H 0 D 0 9 Klemm 9 Lo EU 9
and Drennan 9 P* S*i Paper presented before the Division
of Petroleum Chemistry of the Anu Chem 0 Soe 09 April9
1947
(35
Burk 9 R 0 E 09 and Hughes, E* C 09 (To Standard Oil Co, of
Ohio); U. S* Patent 2,399,662 (May 7, 1946)
>
Frey, F, E 09 (To Phillips Petroleum Co,); U, S, Patent
2,372,320 (March 27, 1945)
(4)
(5) . Frey 9 F, E 09 (To Phillips Petroleum Co*); U 0' S , Patent
2,394,905 (Feb. 12, 1946)
(6 ) .. Ipatieff9 V, N*, and.Monroe 9 G, S 09 (To Universal Oil
. .„ Products Co*); U, S, Patent 2,352, 199 (June 27, 1944)
(75
Ipatieff9 V, No, and Sehmerlihg9 L 09 (To Universal Oil
Products Co, ); Uo S, Patent 2,329,858 (Sept0 21, 1943)
(8 )
Koeh 9 H ; Reichsamt Wirtschaftsaus bau, Pruf-Nr, 102
(PB52004), 49-57 (1940)
(9)
Kutz 9 W 0 M o , and Corson 9 B e Po; Ind 0 Eng, Chem 0 38,
761-4 (1946)
(10) .Lisp9 C 0 B 09 (To Universal Oil Products Co*); U, Se
Patent 2,372,505 (March 27, 1945)
(11)
Linn 9 G 0 B 0, (To Universal Oil Products Co0); U 0 S e
Patent 2,373,580. (April 10, 1945)
(12) . Mattox 9 W 0 J,, (To Universal Oil Products Co,); U 0 S e
Patent 2 ,386,969 (Get, 16, 1945)
(13) . O 0Kelly 9 A, A c, Meadow, J 0 R 09 and Woodward, R 0 E 09
(To Soeony-Vaeuum Oil Co., Ine,); U, S, Patent
2,414,271 (Jan, 14, 1947)
(14) Sehmerling9 L 09 and Ipatieff9 V, N 09 (To Universal Oil
. . Products Co,)s U e S* Patent 2,349,834 (May 3 0 , 1944)
30
(15)
Woodward9 R 0 E o 9 Hawthorne9 W 0 P., and Meadow9 J 0 R 6 9
(To Soeony"VacuTim Oil Co, 9 Inc0) ; H 0 S 0 Patent
2,409,090 (Oet0 S 9 1946)
31
VIII
APPENDIX
Page
A6
B.
C*
!IclDle X ^ o a e o o o e o
e
o
o
o
e
e
o
e
e
o
o
Dealkylation of Xylenes and Calculated Results
e
o
33
e
XaDle XX * 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
.Dealkylation of Monoamyl Benzene and Calculated
Results
3^*
XaDle XXXo e e e 0 0 0 0 0 e 0 0 0 0 0 e 0 0 0 0 0 e 3^
Dealkylation of Biamyl Benzene9 Triamyl Benzene9
. and Calculated Results
36
D0
TaDle IV
Dealkylation of■Toluene9 Diethyl Benzene9 Isopropyl
Benzene 9 and Calculated Results
Eo
XaDle V o o 0 0 0 0 0
0 0 0 0
0 0 0 0 0 0
0 0 0
c o o 37
Dealkylation of Ethyl Benzene and Calculated Results
Fe
- J- 0
F l g U
r e
l
O
o
O
o
O
o
O
O
o
O
o
O
0
0
O
O
0
O
o
O
e
O
o
O
o
O
o
e
O
o
O
e
O
O
o
O
®
O
O
o
O
o
o
o
3^
Diagram of Reaction System
G.
FlgUre R o o o o o o o o o o o o o o o o o o o
Distillation Curves for Runs 3 and 8 (Xylene)
Ee
Figure 3 O o o o o c o o o o o
C O
o
o
o
o
o
o
o
o
Distillation Curves for Runs 11 and 12 (Monoamyl
Benzene)
1»
Figure 4 © O O O O O O O O O O O O O O O O O O O
Distillation Curves for Runs 13 and 14 (Diamyl
Benzene)
K,
L,
o
o
O
o
39
o
40
©
41
Figure ^ ? o O © ‘ O O O O O O O O O
O O
O O O O
O O O O
Distillation Curves for Runs 15 and 16 (Xriamyl • Benzene)
42
O
O - O S O
Figure 6
_
Distillation Curve for Run I? (Toluene)
43
0
6
0
6
0
0
0
0
0
6
0
0
0
0
6
0
0
0
0
0
0
0
6
0
0
0
e
0
e
o
0
Distillation Curves for Runs 18 and 19 (Diethyl
Benzene)
o
o
44
32
Page
H6
Oe
Figure 8 »
Distillation Curves for Runs 20 and 21 (Isopropyl
Benzene)
45
FigUre ^ o o o e o e o o o e o o
o
o
b
e
o
o
e
Distillation Curves for Runs 22 and 25 (Ethyl
Benzene)
46
e
©
FigUre 10 o e e o o e e o o
e 6 @ o o e o e o
-e»e
Distillation Curves for Runs 22, 23, 24 and 25
(Ethyl Benzene)
4/^
TABLE I
Dealkylation of Xylenes and Calculated Results
Run Nd.
I
m & p
Isomer
Catalyst
Act'd
Temp. 0C .
401
Barometer pres. mm.
643.3
Charge cc.
435
Charge5 mols
3.53
Length of run5 hrs6l I
liq. Sp. Vel., Hr.--L 0.484
cc. gas/ mol charge
O
Dist1n charge, grams 363.8
Dist8n pressure, mm. 647.6
Chaser
Tetradecane
Toluene
Refractive Index
Boiling Point, °C.
io Liquid Product
O
Conversion, % Theor.
Ultimate yield, $
Trimethyl Benzene
Refractive Index
Boiling Point, °C.
% Liquid Product
O
Conversion, % Theor — Ultimate yield, %
,
—
---------------
.
— — —
2
m & p
Act'd
440
3
m & n
Act'd
510
6 4 3 .7
643.7
500
735,
5.96
4.05
I
I
0.818 0.556
414
1611
593.4 400.1
644.2 635.2
Tetra- Tetradecane decane
4
m & p
Act'd
542
637.4
385
3.13
I
0.428
3860
6
8
7
m
0
m & p
Act'd Act'd Unact'd
508
522
504
645.1 628.5 635.2
320
385
635
2.66
3.12
5.14
I
1.42
0.75
0.429 0.474 0.498
490
1740
745
264.3
3 1 1 .6
527.8
313.3
642.4 6 2 8 . 0
637.4 6 2 6 . 5 634.8
Tetra- Amyl Amyl
Amyl Tetradecane BenzeneBenzene Benzene decane
5
p
Act'd
504
647.3
340
2.75
O.8 3
0.455
360
263.3
1.4964 1.4961 1.4968 1.4951
104
103
103
103
12
12
15
17.5
16
12.9
19.1
12.7
36.4
51.6
36.8
35.3
1.5042 1 . 5 0 3 6 1.5040
160
159
159
16
18.5
13
13.1
10.9
15.3
29.4
42.0
2 9 .5
103
8
8.7
36.4
1.4960
103
13.5
14.7
37.8
1.4995
160
10
1 2 .5
10.0
9.4
1.5039
160
19
_
1 2 .5
M
40.1
— — —
— — —
160
2 8 .9
3 2 .8
———
*C-J C=
0
•
W W-
• — Wm CW
——_
_
0
aw
34
TABLE II
D e a l k y l a t i o n of M o n o a m y l B e n z e n e a n d C a l c u l a t e d R e s u l t s
Run No.
Catalyst
Temp °C.
Barometer Pres. mm.
Charge, cc.
Charge, mols
Length of run, hrs.
Liq. S p . Vel, Hr.-I
c c . gas/mol charge
Dist1n charge, grams
Dist'n Pressure, mm.
Chaser
9
act'd
427
641.5
710
4.12
1.50
0 .5 2 6
586.5
6 3 8 .6
tetradecane
Benzene
Refractive Index
1.5005
Boiling Point, 0C „
74
% Liquid Product .
41.5
Conversion, % Theor.
75.5
Ultimate yield, %
93
10
act'd
504
635.5
770
4.46
1.75
0.489"
6040
574.7
631.9
tetradecane
11
act'd
504
641.5
1.5009
74
51
84
84
1.5003
74
52 ^
87.5
87.5
790
4 .5 7
1.67
0.527
5750
601.1
635.2
tetradecane
12
unact'd
503
638.2
525
3.04
1.17
0.500
4460
416.8
641.7
tetradecane
1.4992
74
16.8
75
35
T A B L E III
D e a l k y l a t i o n of D i a m y l B e n z e n e and T r i a m y l B e n z e n e and
Calculated Results
Run No.
Compound
Catalyst
Temp. °C.
Barometer pres.9 mm.
Charge 9 cc.
Charge, mols
Length of Run, hrs.
Liq., S p o Vel., hr.
cc. gas/ mol charge
Dist’n charge, grams
Dist’n pressure, mm.
Vacuum pressure, mm.
Chaser
13
Diamyl
Benzene
Act'd
498
635.5
765^
2.98
1.67
0.508
10,860
510
6 3 7 .1
85
Triamyl
Benzene
Benzene
Refractive Index
1.5002
74
Boiling Point, OC.
% Liquid product
29
Conversion, % Theor. 63.3
Ultimate Yield, %
63.3
Amyl Benzene
-1.4892
Refractive Index.
Boiling Point, °C.
IlS85
% Liquid product
23
Conversion, % Theor. 26.4
26.4
Ultimate yield, %
Diamyl Benzene
Refractive Index
Boiling Point, 0C .
% liquid product
Conversion, % Theor.
Ultimate yield, %
e=
*=«
*
>
. 14
Diamyl
Benzene
Unact1d
496
638.2
2.08
1.17
0.510
6,430
428.5
641.7
85
Triamyl
Benzene
0
«=—•=*
ass S
b
1.4889
182
28
38.8
76.6
15
Trlamyl
Benzene
Act'd
499
635.5
760
2.39
1.75
0.482
2 5 ,1 0 0
530.2
634.8
85
None
1.4998
74
13.7
39.0
39.0
1.4892
11865
16
Triamyl
Benzene
Unact'd
500
638.2
525
1.60
1.17
0.500
17,600
4 0 5 .5
85
None
S
3S
SS
B
Trace
S
3S
SS
S
«
=
»
S
3
S
S
___
S
SS
B
C
=
.
2 8 .3
Trace
42.3
42.3
aaosr.
1.4826
1.4824
1 3 .7
1 3 .7
41.1
60.0
a eso
t>
■
SS
B
S
B
IT .P
csosa
S
3S
B»
■ow
e=
«3—
S
B
S
3S
3
36
TABLE IV
Dealkylation of Toluene, Diethyl Bdnzene, Isopropyl Benzene
and Calculated Results
Compound
Toluene Diethyl Benzene
Run No 0
Catalyst
Temp. 0Ct
Barometer Pres., mm.
Charge, cc.
Charge, mols
Length of run, hrs.
Liq. S p . Vel., hr.”1
cc. gas/mol charge
Dist'n charge, grams
Dist'n pressure, mm.
Chaser
17
Act'd
499
636.3
580
5.41
1.37
0.472
170
462.8
18
19
Act'd Unact'd
*99
503
638.7
639.3
570
635
3.66
4 .0 7
1.42
1.25
0.507
0.499
10,900 1,550
451.0
469.8
641.8
6 3 6 .6
635.9
Diethyl Tetra- TetraBenzene decane decane
Benzene
Refractive Indfex
——
Boiling Point, °C
--% Liquid Product
0
Conversion, % Theoz1e- Ultimate Yield, % — —
Ethyl Benzene
Refractive Index
Boiling Point, °C. —
% Liquid Product
Conversion, % Theor.-—
Ultimate Yield, %
■»■»€=>
■=•=»
0
O
*» *D W
m om om m
— —
1.4959
127
*==•» OB
O
38.6
68.1
Co*==-
Isopropyl
Benzene
21
20
Act'd Unact'd
500
505
634.2
634.6
545
725
5.21
3.92
1.58
1.17
0.510
0.519
6 ,4 6 0
2,280
451.0
487.0
634.2
634.4
Diethyl Diethyl
Benzene Benzene
1.5003
74
72
86
86
74
2
2.9
40.8
mm m om s*
m s mm mm
mmmmmm
— —
———
• = « « =
37
TABLE V
D e a l k y l a t i o n of E t h y l B e n z e n e
Run No.
Catalyst
Temp. 0C.
Barometer Pres.9 mm.
Charge, ce.
Charge, mols
Length of run, hrs.
Liq. Sp. Vel.,hr."1
ce. gas/mol charge
Dist1n charge, grams
Dist'n pressure, mm.
Chaser
22
Act'd
507
639«3
620
5.06
1.33
0.518
2,540
507.7
635.9
Tetradecane
24
23
Carboned Burned Off
522
508
632.9
629.3
490
505
4.00
4 .1 3
1.00
1.17
0.560
0.467
1,380
815
403.4
420.9
639.3
629.3
TetraTetradecane
decane
■=»***D
0
1.4997
74
5.5
7.2
31.4
25
Unact’d
502
635.2
535,
4.36
1.17
0.510
775
453.6
637.1
Amyl
Benzene
<k >t e o
o
Komomo
0
0
OD
6.0
4.6
25.8
II
8O
II
I
Benzene
Refractive Index
1.5009
Boiling Point, °C. 74
% Liquid Produce
13.5
Conversion, % Theor.17.4
Ultimate Yield, % 59.6
Diethyl Benzene
Refractive Index
1.4965
Boiling Point, 0C 0 170
% Liquid Product
6.5
Conversion, % Theor.4.9
Ultimate Yield, % 16.8
and C a l c u l a t e d R e s u l t s
«*■=»*
38
3k
BE R L
SADDLES
THERMOWELLS
CATALYST
BERL
SADDLES
DRY I CE
COND EN SER
FEED
A
WATER _
CONDENSER
TO BLOW
DOWN
BELLOWS
CAS
PUMP
RE CEI VER
Figure I.
Diagram of Reaction System
METER
______ I
160
3 140
XYLENE
Lu
NO
h- 120
XYLENE
o
ACT'D
CATALYST
•UNACT'D
0
20
4-0
WEIGHT
Figure 2.
PER
60
CENT
CATALYST
80
DISTILLED
Distillation Curves for Runs 3 and 8
100
A M Y L
B E N Z E N E
B E N Z E N E
AMYL
BENZENE
RENTE NES
ACT'D
•UNACT'D
WEIGHT
Fi g u r e
3
PER
C E N T
CATALYST
CATALYST
DISTILLED
Distillation Curves for Runs 11 and 12
D I A M Y L
BENZENE
B E N ZENE
A M Y L
BENZENE^)
BENZENE
DIAMYL
BENZENE
o ACT'D
C A T A L YS T
• U N ACT'D
P E N T E N E S
WEIGHT
Figure 4
CATALYST
--- Dl S T 1N A T 8 5 M M
40
PER
CENT
60
DISTILLED
80
D i s t i l l a t i o n - C u r v e s for Run s 13 and 14
A BS.
TRI A M Y L
BENZENE
DIAMYL
BENZENE
z>
140
AMYL
BENZENE
I
J
BENZE
TRIAMYL
0
PENTENE
20
WEIGHT
Figure 5.
40
PER
CENT
BENZENE
ACT'D
CATALYST
• UNACT'D
CATALYST
-DIST'N
85
60
DISTILLED
AT
80
Distillation Curves for Runs I5 and 16
MM.
ABS.
TOLUENE
I- 9 0
TOLUENE
ACT'D
CATALYST
60
WEIGHT
F i g u r e 6.
PER
CENT
DISTILLED
D i s t i l l a t i o n Curve for R u n 17
B E N Z E N E
ETHYL
B E N Z E N E
VAPOR
T E M P E R A T U R E
DIETHYL
DIETHYL
o
ACT'D
• UNACT'D
WEIGHT
Figure
7»
PER
CENT
BENZENE
CATALYST
C A TA L Y S T
DISTILLED
D i s t i l l a t i o n Curves for Runs 18 and 19
I70
ISOPR O P Y L
BENZE
N E
I
U
O
w
K 130
D
I<
K
U
CL
5
vn
UJ
l<r
O
90
CL
03
<
>
I
N Z E N E
/
ISOPROPYL
o ACT'D
50
• UNACT'D
I
0
20
W E I G H T
Figure 8.
40
PER
C E N T
60
DISTILLED
BENZENE
C A T A L Y S T
CATALYST
80
D i s t i l l a t i o n Curves for R uns 20 and 21
100
DIETHYL
150
T E M P E R A T U R E
U
BENZENE
B E N Z E N E
VAPOR
E T H Y L
E T H Y L
BENZENE
ACT'D
• U N ACT'D
WEIGHT
Figure
9.
40
PER
CENT
B E N Z E N E
CATALYST
CATALYST
60
DISTILLED
D i s t i l l a t i o n C u r v e s for Runs 22 and
25
DI ETHYL
ETHYL
b e n z e n e
BENZENE
H-
O
O
C5
CD
o
Ul
y BEN ZEN E
WEIGHT
Figure 10.
40
PER
CENT
BENZENE
CATALYST
e
U N ACT'D
a
CARBONED
9
20
ETHYL
ACT'D
BURNED
60
DISTILLED
CATALYST
CATALYST
OFF C A T A L Y S T
80
Distillation Curves for Runs 22, 23, 24 and 25
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