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June 20, 1950
Filed Sept. 24., 1946
mvdnl'mwr§<[email protected]î_.1b
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Patented June 20, 1950
Charles E. Morrell, Westfield, Harold W. Schee-
line, Llewellyn Park, and Carl S. Carlson and>
Harry J. Heinemam'Jr., Elizabeth, N. J.,_ as»
_ signors to Standard Oil Development Company,
a corporation of Delaware
' `
Application September 24, 1946, Serial No. 699,014 `
i claim. (o1. zet-_666) _
-This invention >relates to a practical method y y
,and means for obtaining cycloalkadienes of high
.purity from cracked petroleum oils.
' Prior to the present invention there has been no
economically feasible method of procuring cyclo- y
alkadienes from petroleum oils.
It is known 'that limited amounts of cyclopen
tadiene have beenv commercially available only
_by‘processing of coal tar oil forerunnings, in which
.-cyclopentadiene is present as the monomer.` This
cyclopentadiene is recovered from the light ends
of the coal tar forerunnin-gs, containing mainly
benzene, by the steps of:
(l) Heating the light ends under high pressure
without vapor-separation until as much of the
monomer as possible is polymerized therein,
(2) Distilling the aromatic light ends from the
products issuing _from the cracking Zone are
quenched to a temperature at which thermal poly
merization of the non-cyclic unsaturated hydro
carbons is repressed- in order_to obtain a high
yield of the low boiling alkadienes, such as buta
pentadienes, and the like.
„19 diene,
This invention is also concerned with effecting
separation of an aromatic naphtha fraction from
the higher boiling Icracked products and separat
ing from the lower boiling unsaturated hydrocar
bons a _heavy portion of the aromatic naphtha
fraction as bottoms inl such a manner as to ac
cumulate,cycloalkadiene polymers in vthis heavy
aromatic naphtha Lfractionbefore it is subjected
Ipolymer which remains as a bottoms or residue,
. l (3) Vacuum
Cracking the thus purified cyclopentadiene '
polymer from the bottoms, and
turnings or similarjmaterial. ~
of >unsaturated hydrocarbons -and aromatics in
The method by which ‘cyclopentadiene is re
covered from light ends of coal tar forerunnings
iis not practically applicable to cracked petroleum "
_f-distillates which contain very small amounts of
cyclopentadiene> monomer and in which many
.otherhydrocarbons of unstable characteristics are
cracking volatile petroleumV cracking stocks, such
as naphtha cuts, kerosene, or gas oils, are high
temperatures of the order of 1000° F. to 1600° F.,
preferably'l200". to l500° F., Iand lov»7 pressures
of the order of l to 10 atmospheres. The charg
ving'stock is preferably diluted with up to 90 mole
¿per cent of steamin the cracking zone in order to
No satisfac- ._
_story method has been found for separating cyclo- `
pentadiene polymer from cracked petroleum prod
restrict carbonìzation,
.thermal cracking of gas oils or heavy naphthas.
The hot cracked products issuing from the
cracking zone are quenched to a ’temperature at
fucts such as may be-obtained, for instance, from
_ _ An object-«of this invention is-to provide a com
to a heat treatment under proper conditions for
converting the cycloalkadiene polymers to mono
mers without undesired side reactions, and subse
quently isolating thé monomers,
Conditions favorable for obtaining high yields
'polymer distillate in a column packed with iron
present in much larger quantities.
dimethyl cyclopentadienes, hexadienes, cyclo
hexadienes, methyl cyclohexadiene, dimethyl cy
clohexadienes, and the like.V The aromatics ln
clude benzene vand its homologs. The cracked
>hydrocarbons boiling above the naphtha
35 'which
boiling range are condensed,then the naphtha
„mercially feasible process of »obtaining cycloalka- ‘ ‘
vidienes,-such as, cyclopentadiene and methyl cyclo
_.pentadiene,l each in a substantially pure state,
_-from cracked petroleum products by collecting inv
the bottoms o_i1an aromatic naphtha distillate, i
«polymers of the cycloalkadienes formed in the "‘
~and lower boiling hydrocarbons are fractionated.
By processing the highly cracked products formed
in this manner, the cycloalkadienes show up in
v'the final naphtha product both as monomers and
polymers. It is found that the amounts of the
.cracking and naphtha fractionation operation,
cycloalkadiene monomers present in the low boil-v
then heat treating and processing the aromatic
'ing cracked products are so small as to make their
¿distillatebottoms in such a vmanner as to evolve
,substantially pure monomer distillates therefrom.
Among its objects, this invention is primarily
concerned with obtaining C5 to Ca oycloalkadienes
_from cracked petroleum distillates produced under
separation therefrom unsatisfactory. VIt is found,
however, that the ,cyçloalkadiene polymers >can
be eiiiciently collected in avh'eavy aromatic naph
thafiraction of the'cracked products without sub
stantial loss Vby decomposition. and that high
purity cycloalkadiene monomer cuts Vcan be ob
¿_suiiiciently severevapor phase cracking conditions
;as to form~ considerable amounts of mono-oleñns, 50 tained from the polymers in the heavy aromatic
_dioleñns, and aromatics.
The mono-olefins, or' -
,alkenes, include `largely ehylene, propylene, and
_Íbutylenes The diolefiins include the non-cyclic
naphtha fraction by a subsequent heat treatment.
In processing the quenched cracked petroleum
products', theV aromatic naphtha together with
alkadienes and Vthe cycloalkadienes such as, buta
the lower 'boiling hydrocarbons and steam are
'|_dienes, pentadienes, ~`c'y'clopentadiene, methyl and
`,removed overhead y' from ythe higher boiling
cracked products which are quenched to a liquid
state. The overhead naphtha vapors and steam
controlled to evolve very little of other lower
boiling hydrocarbons which would interfere with
separation of a high purity cyclopentadiene cut.
Any gaseous hydrocarbons formed are readily
are condensed by cooling, but some or all of
the normally gaseous hydrocarbons may be al
lowed to remain in gaseous state. Water con
densate is separated from the thus-obtained
aromatic naphtha distillate.
After separation of the water condensate, the
aromatic naphtha distillate is subjected to a
separated from the quenched heat treated naph
tha before liberation of the cyclopentadiene
monomer or are separated from the cyclopenta
diene monomer distillate taken overhead while
repolymerization of the monomer is minimized.
In a manner similar to that described for ob
fractional distillation to remove therefrom any 10
remaining condensed C1 to C5 hydrocarbons, and
if desired, C6 to C‘g hydrocarbons. This fractional
distillation is performed without heating the dis
tillate to above the normal boiling points of C's
non-aromatic hydrocarbons and may be carried 15
out by passing the distillate into one or a series
of topping towers, such as demethanizing, de
taining the cyclopentadiene monomer, its homo
logs, such as, methylcyclopentadiene, dimethyl
cyclopentadiene and cyclohexadiene can also be
separated from the cracked petroleum products,
with the modiñcation that the aromatic naphtha
distillate is freed of C6 to Cs hydrocarbons as
well as the C1 to C5 hydrocarbons prior to the
heaty treatment. The methylcyclopentadiene and
ethanizing, depropanizing, debutanizing, and de
cyclohexadiene polymers along with cyclopenta
pentanizing towers, for removal of the lower boil
ing C1 to C5 hydrocarbons. It is desirable to re 20 diene polymers are collected in the heavy ends
of the aromatic naphtha distillate and their
move non-aromatic C6 to Ca hydrocarbons from
monomers are liberated by the heat treatment.
the aromatic naphtha distillate if higher cyclo
rThe monomers can be collected as one or more
alkadiene homologs of cyclopentadiene are to be
distillate cuts after which they can be subjected
recovered. It is not necessary to remove the Cs
to C5 aromatics, but those which distill olf with 25 to further distillation, if necessary.
Having outlined the process of the invention
the C5 to Ca non-aromatics can be removed there
in a general manner, further specific details will
be explained with reference to the accompany
ing drawing which schematically illustrates a
a distillation aid such as steam or vacuum.
The conditions of the fractional distillation 30 flow diagram of means and steps in carrying out
a preferred embodiment of the invention.
treatment are thus controlled so that the ratio
In the ñow diagram I represents a high tem
of cycloalkadiene polymers retained in the aro
peratfure steam cracking zone into which a
matic naphtha bottoms is kept high with respect
petroleum cracking stock is charged from line 2
to their monomers originally present in the
cracked product streams. The remaining aroma 35 and steam or preheated Water is supplied from
line 3, the oil charging stock being in the liquid
tic naphtha bottoms following sepa-ration of C5
or preheated vapor condition. The cracking
and lower boiling `hydrocarbons boil mainly in
zone may be contained in a fired pipe coil or
the range of 176° F. to 456° F. and following
other conventional type of cracking apparatus.
separation of C5 and Cs hydrocarbons, the aroma
tic naphtha bottoms are higher boiling and con 40 Steam or preheated water may be supplied at a.
multiplicity of points to the coil. The cracked
tain largely alkyl aromatic homologs of benzene
with, and in removing the C6 to Ca hydrocarbons,
both aromatic and non-aromatic, it is best to use
with cycloalkadiene polymers.
Following the separation of the C5 to C8 and
lower boiling hydrocarbons from the aromatic
naphtha fraction, the resulting heavier aroma 45
tic naphtha bottoms is subjected to a heat treat
ment in which the temperatures employed are
in the range of 300°-800° F. The heat-treated
aromatic naphtha bottoms are entirely or partly
products leave the cracking zone through line
4 and are promptly quenched by introduction of
cool liquid cycle oil introduced by line 5 into
line 4. The quenched cracked products are dis
charged from line 4 into a fractionation zone 6
from which cracking tars are withdrawn by line
'I and liquid cycle oil is withdrawn as a side
stream by line 8. Cooled cracked naphtha vapors
in vapor phase or entirely in liquid phase depend» 50 together with steam and gases are drawn over
head from the fractionation zone Iì through line
ing on the actual temperature and pressure of
9 and through cooling condenser I0 into a.
the heat treatment and the end boiling point
separation zone II. Uncondensed gases leave
of the naphtha.
the separation zone through line I2. Water con
In general, the end boiling point of the heat-treated naphtha bottoms is not above 500° F. and 55 densate is removed from the bottom of the sep
aration zone through line I3 and naphtha dis
the heat treatment pressure is atmospheric pres
tillate, which may include varying amounts o!
sure or slightly thereabove, so that a partial or
condensed C1 to C5 hydrocarbons, is withdrawn
complete vapor phase operation is obtained. >The
through line I4 from the separation zone II to
naphtha bottoms are exposed to the heat treat
ment for as short a period as is necessary for 60 a _fractional distillation means I5.
conversion of the cycloalkadiene polymers to the
monomers with minimum cracking or decom
The uncondensed gases withdrawn from the
separation zone II through line I2 may be sub
position of other naphtha components to sub
stances which would interfere with separation
jected to compression and cooling for lique
«or quenched heat-treated naptha bottoms as .a
minimize decomposition of cyclodioleñn polymers.
faction by means not shown in the drawing and
of the monomers by distillation.
65 then be combined with the aromatic distillate
supplied to the fractionating means I5 »for -com
The best results in the vapor phase heat treat
mon fractionation therein.
ment were obtained at temperatures of 600° F. to
The fractional distillation means -IÍE may com
`@450° F. for a duration `of 0.15 to 25 seconds. Liquid
prise one or a series of towers, only one being
phase heat treatments require up to 1.0 hours at
300° F.
70 vshown for convenience and simplification. 'I_n
the fractionatinlg means I5 the naphtha distil'
The >cyclopentadiene .monomer liberated by the
late is kept at as low a temperature as possible
heat treatment of the .aromatic knapbtha bottoms
during removal of C; to C5 hydrocarbons `to
is taken overhead by distillation from .the .cooled
C5 distillate cut.
The heat treatment is thus 75 >Steam or similar gases may -be 'introduced into
the> fractionating means for lowering the dis
tillation temperatures of the hydrocarbons which
diene present as monomer,`polymer. or both, in
the C1 to Cs cuts fractionally distilled from an
are to be stripped from the aromatic distillate.
aromatic cracked naphtha' obtained in steam
One or more of the C1 to C5 cuts may be jointly
cracking a gas oil at 1250°-1265° F. and remain
or separately removed through the lines I6, I1,
I8, I9 and 20 and similarly in certain cases Cs
to Cs cuts.
In recovering a C4 cut from the f_ractionating
ing in the aromatic naphtha. bottoms.
Distribution of eyczopeniadiene in cuis fraction
means l5 as a separate stream withdrawn, for
atedv from a cracked aromatic naphtha distillate
example, through line I9, this stream will con 10
tain large amounts of butenes and butadienes
mixed with some C4 paramns. A C5' stream With
drawn, for example, through line 20 contains
pentenes, pentadienes, C5 parañins, and a small
amount of cyclopentadiene monomer. The thus 15
topped aromatic naphtha distillate is Withdrawn
Per Cent
as bottoms from the fractionating means l5
through line 22 to the heat treating zone 23 which
is combined with a fractionating means 24.
‘ As previously mentioned, it is not necessary to
remove Cs hydrocarbons completely, if only cy
clopentadiene is to be obtained from its polymers
Flnal Temp.. F.
, In stili
- 25
Weight Per
__________ __
0. 5
0. 1
4. 1
The cyclopentadiene present in the cuts 1, 2
in the aromatic naphtha bottoms and therefore
and 3 represented the original cyclopentadiene
benzene may remain in the bottoms. If Cs to Ca
monomer which has a normal boiling point of
cycloalkadienes are to be obtained from their 25 105.851“, The results show that a preponderance
polymers in the aromatic naphtha bottoms, then it
0f the cyclopentadiene in the cracked aromatic
is desirable to remove from these bottoms Cs to Ca
naphtha distillate was present as polymer.
hydrocarbons as Well as the C5 and lighter hydro
Typical> dataA obtained in the heat treatment
carbons and more particularly to remove the Ce
of the topped aromatic naphtha are shown in the
to Cs non-aromatics.
30 following tables:
The heat treating zone 23 may Ibe in the form
of a heated tube or tank. ‘ In this heat treating
Yields of cyclopentadiene from its dimer in topped
zone the topped aromatic naphtha fraction is
aromatic naphtha distillates of steam cracked oils
heated to 2, temperature in the range of 300°-800°
F. and at these temperatures the polymers of les»
cyclopentadiene and its homologs undergo rapid
depolymerization to the monomers. ‘ The heat
treated aromatic naphthaJ bottoms is discharged
from the heat treating zone 23 through line 25
into the fractionating zone 24 preferably with 40
addition of quenching liquid from line 26. This
quenching liquid may be cold water, coldl aro
matic naphtha, distillate bottoms or similar liq
uid which will not introduce interfering distilla
tion components.
By quenching, the hot products leaving the
heat treating zone are suddenlycooled to below
300° F. They may be thus cooled to below 100° F.
to avoid cycloalkadiene repolymerization.
Distillaticn of the heat treatment product fol 50
lowing the cooling is carried out in such a way
Treatment qlgäggéct
` Temp.,Í
wi . Per ‘ët'ycim
a~ wi . P er o en i
Seconds Liquid Re-
diene Yield Cyclopenta
Based on
Naphtha Before Topping
diene Loss In
18. 9
2. 2
2. 8
0. 02
0. 04
0. 2
Y 100
3. 1
0. 0
Yield of cyclopentadiene from a synthetic mixture
of 4.56 wt. per cent dicyclopentadiene in aro
"matic naphtha of 300-400° F. boiling range
Heaít'íl‘reat- C'Iontact Wëèîfr Wtáfligelâîfent
men emp"
Liquid Cyclopentaas to minimize polymerization of cycloalkadiene
Seconds Recovery
monomers. The distillation preferably follows
the quenching immediately. Steam may be intro
21. 3
4. 1
duced into the distillation and fractionation 55
means either directly or as quench ñuid. Hold up
time in the distillation and fractionation is mini
mized. The temperature of overhead vapors from
Recovery of cyclopentadiene and alkyl homologs
the fractionation means 24 should preferably
of cyclopentacliene by depolymerization of dì
not exceed 120° F.
mers in cracked distillate topped to remove Cs
Overhead of cyclopentadiene vapors are with
and lower boiling components
drawn from fractionating means 24 through line
21 and cooler 28 into receiver 29 for collection of
cyclopentadiene monomer cut. A methylcyclo
Wt; l’er Cent Yield From
Aromatic Distillata
pentadiene fraction may be Withdrawn from frac 65
tionating means 24 through line 30. Higher boil
Tune’ Sec’ Recovery C C10 ents” substituted
ing homologs may be withdrawn as separate
y .e216
streams from fractionator 24. The remaining
high boiling aromatic naphtha freed of polymers
of cyclopentadiene and its homologs is withdrawn 70
o. 25
17,. 8
2. 7
0. 24
from the fractionating zone 24 through line 3|.
Experimental data Were obtained in investigat
ing operations performed in the manner de
The points of interest shown by the data in the
scribed and tabulated results given in the follow
Tables 2, 3 and 4 are summarized as follows:
ing table show the distribution of cyclopenta 75 (a) Cyclopentadine losses resulting from the
topping of` the; aromtienaphtha distillate.asem--~
repressed, separating from the quenched [email protected]
productsy an aromatic; naphtha. distillate: fractioni
, (-bù? Í'Recovery oii'monomer. fromtheheat ,treat-H
containing cyelopentadiene monomer’A and cyclo-1
ed dilute> solution of polymer in-a aromatic- naphtha.I
pentadiene dimer distilled with steam, distilling,
Crthrough C5 hydrocarbons including the cyclo-A
fraction is good, cf the orderof 90% or` better. 5;
(Table 3);
Y, ,
(c) A higher yield of cyclopentadiene> is ob
tainedì With heat.: treatments. of shorter duration-
pentadiene monomer from said aromatic naphtha
distillate fraction to obtain a residual fraction 0f*l
the aromatic naphtha boiling in the. range' of
176° F. to- 450° F. and. containing» thecyclopentam
at 600%300" F; than: at300°-600° E'. (Tabled):
(d) In obtaining the results shown in Table 4, 1:0 diene dimer in. low concentration withy higher
boiling aromaticy hydrocarbons, continuously
the C5 fraction distilled overhead from the heat
passing. said' aromaticV fraction. in» liquid phase',y
treated aromatic naphtha bottoms was substan
without vinterinediete separation of the cyclo-À
tially 100% cyclopentadiene andthe C6 fraction
pentadiene dimerl as vapor therefrom,` through a.
obtained was substantially 100% methylcyclo
pentadiene‘. Other hydrocarbons were hardly de-. 15 dlepclymeriza,tionv reaction- zone at a, temperature-l
of«,300.-‘«’ tof600° F. todecompose/the cyclopenta-f
tectable in these two distillate fractions.
(e) High purity and yields of cycloalkadiene'
diene- dimer contained in the liquid phase aro*
matic hydrocarbons», continuously withdrawing
products are obtained by the method of topping„
heat treating the topped naphtha (bottoms) un-y
fromn said- [email protected] zone; an* eiiiuent of the liquid;
der proper conditions, and fractionating these- 20» aromatic hydrocarbons from the heat treated aro
ma-tic fraction andr the. cyelopentadienev monomer
products from the heat treated naphtha bottoms
cranes V2, 3 ande).
s The separation of
vapor. formed by depolymerization- of the dimer..
immediately,l cooling the withdrawn cyclopentadi->
the` cyclo'alkadienes `in the,>
manner. described ishelpiul to the recovery of the.
non-,cyclic diol'eñns. andv advantageously improves.
the stability of the final aromatic naphthay
enemonomer vapor and» fractionatingsaid vapor
in a tractional distillation zoner in which the over
head vapors> have a. temperature not. exceeding.
120° F. to obtain an overheaddistillate of cyclo,
» Thel cycloalkadienes
' _
recovered iny the- manner
pentadiene monomer substantially free of> other.
described. are useful. ink chemicalf reactions as.
monomers or they may be subsequently converted.. 30a
to pure dimers or high polymers by thermal or
catalytic polymerization methods. These mate
rials are important iny the manufacture of highly1
unsaturated oils, plastic polymers and resins
which may be utilized in surface coatings, ink
oils, various drying compositions, synthetic ñbers;
etc. The invention has been described with ref-erence to preferred modifications and adapta
‘ ' The following referencesv are *ofv record` in. the.
ñle` of this patent:
cations come within theA scope of the invention 40: Number
Lycan et al'. _______ __ May 16, 1944.
as defined in the appended claim,
tions, but it is to be understood that other modifi
Smithv ............ __ NOV. 28, 194.4
A process of producing and recovering mono-
Chaney _.. _________ __ Feb. 13„1945l
meric cyclopentadiene >of high purity in cracking
Doumaniet. al _____ __ JuneY 4,` 1946i
Birch et al _______ .__ Sept. 10,1946.
Doumani et al ..... __ Oct. 15, 1946
Latchumf,` Jr _______ __ Jan..21, 1947.
We claim:
a petroleum oil boiling-in theheavy naphtha and
gasoil range, whichcomprises-cracking the pe-i
troleum oil in- vaporvphaseata temperature in
therange of 1000° F. to,l 1,600.9 F. in the presence
of steam under a pressure of 1 to l0 atmospheres,
promptly quenching the resulting cracked petro
leum products to a temperature> at which thermal
polymerization of unsaturated hydrocarbons is
Staff _______________ _... NOV. 2., 1948-
VBirch et al.: Jour. Ind. Eng. Chem., vol. 24.,
‘1g-5.0 (1932).
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