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Патент USA US2370810

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March 6,
c. E ,MORRELL E‘rAl.
Filed Aug. 21, 1942
‘2,310,816 l
, :Patented Mar# 6,11945 A `
r'nocnss ron sEGnEGA'r'ING vALUABLa
mmaocmaon coNsTrrUnNTs
Morrell, Roselle, and Miller W.
Swaney, Linden, N. J., assignors to Standard
0i! Development Company, a corporation ¿of
f Delaware P
' ' 1oAugust
serial No..455,s7c
The `presentinvention relates to the art ofthe
segregation of certain unsaturated hydrocarbons
from mixtures with other hydrocarbons of closely
similar boiling points, and more speciilcally to the
the above mentioned process by which increased
yieldsmay be obtained.
~ -
Referring to the drawing, numeral E_denotes. a
line through which the hydrocarbon feed is in
troduced. For purposes of illustration, a refinery
.Ca cut from cracking' operations will be taken
separation and purification of tertiary oleflns
from their mixtures `withvnorinal or- secondary
y oleñns or from saturated hydrocarbons.
' but it will be understood that a Cs cut or other
mixture of hydrocarbons including tertiary oleñns
The process will be understood from the fol
lowing description and drawing. The drawing- is
might be taken equally well for purposes of illus
asemi-diagrammatic view in- sectional elevation 10 tration. ‘ The cut‘ is preferably a rather narrow
showing the ilow of the various materials em
boiling fraction, such as can be readily producedA
ployed in the process. *
in ordinary reiinery equipment without great
Tertiary oleñns, such as isobutylene and iso-.
.difñculty. The feed stock is preferably fed in
amylenefoccur together with many’ other oleflns,
liquid phase and sufficient pressure is imposed to
maintain it throughout the absorption step.
,both normal and secondary, as well as saturated
hydrocarbons.' in cracked 'hydrocarbon oil frac;v ,
In addition to the feed stock, a second" liquid
hydro-carbon of a higher boiling point than _the
. tions, and it-has been for some time desirable to
develop- a’chïeap, effective method for segregating
~ original feed s'tcck, but boiling below the boiling*
point of the phenolic material used, is also sup-`
the tertiary oleilns from other constituents in‘
narrow boiling cuts. In the lower molecular 20 plied by the pipe 2. The nature of this hydrof.
weight ranges, forexample,- in'the so-called C;
carbon,-which is termed the “added hydrocarbon” l
5 will be more speciilcally disclosed later. A suit
and Cs cuts, which comprise those hydrocarbons
having 4 and 5 carbon atoms respectively inthe
molecule, separation can be accomplished by dis
tillation but ‘due to the close boiling points, this
is a very diilicult and expensive operation. Bet
’ ter results have been obtained by chemical
means; for example», isobutylene has been selec
tively extracted from normal butenes and butanes
by solution in 65% to 75% sulfuric acid.' Acids
of this strength absorb the tertiary olefin without
substantially> añecting the normal olefins or
_ parafllns, and the iso-olefin can be recovered from
the acid liquor by dilution Iand distillation.
' Another methodî of accomplishing the same re
sult employsfa mixture of phenols, cresols and
able, absorption medium, which for the present
will be described as a, phenolic material, is added
through a pipe 3 and the mixture of thesè three
materials is passed through an absorption zone t
by way of a common leader pipe da. An alkylat
ing catalyst supplied by pipe 4b isfsmall in amount.
and it is preferably also added to the leader.
30 This mixture of ingredients now passes' through
`the absorption zone 4 in liquid phase. Any par
ticula'i- desigm for the absorption zone may be
employed in which all of _the ingredients are
mixed thoroughly and given soient time for
er" reaction. As shown in the drawing, the reaction
the like along with" a minor amount of- mineral
zone is' merely a pipe ñtted with bañies-b and a
jacket 6a through which a coolingmedium may
alkylation acid by 'means _of which the reactive
tertiary oleflns are caused to unite with“ the
phenolic material to .form an alkylated phenol.
>~be circulated, since there is considerable heat
evolved in the alkylation step. The conditions
. The unailectedhydrocarbons may be distilled oilI
to alkylate .the phenolic material, the other oleñns
from this product and the residue, which' consists
of the alkylated phenol, is then heated to effect
the dealkyl'ation so that the .tertiary oleñn is'then
' are such that only the tertiary olefins are caused
passing' through substantially unaüected. The
reaction product is discharged through a heating
coil Gf and into a distillation column l which is»
collected and the phenol returned.
This method is not -entirely satisfactory be- '
cause of the fact that the yield is not as high as-
coil> 8 at its lower end; In this fractionating zone,
-the ~'uncombined hydrocarbons, namely the
might vbe desired due- to Several factors; ilrst,
- butanes and the normal butenes, are distilledy ` '
polymerization oi’ the tertiary oleiin: second, the
>provided with a reñuxing coil 8 and a reboiling`
overhead through a pipe l0, condensed in acon- -
fact that some tertiaryoleiln's are. distilled over 50 denser l2 and collected inthe drum I3 through
which they may be withdrawn as a liquid, _by pipe
along with the unalkylated tractionsfof the feed
stock and, infra, because of the amenity-'m- com
pletely removing the absorbed tertiary olefin from
the phenolic material inthe recovery step. The
present invention involves an ‘improvement over
I _4, From the base oi' the tower 1,. the residue con
taining the alkylated phenolic material and the
added hydrocarbon along with a small amount of"
.alkylation catalyst passes by pipe» IB through a -
“ j andere
material without causing any substantial poly
heat exchanger II and a second heating coil l1 y
"and thence into aA stripping tower In Thistower
merization of the tertiary oledn.
An important feature'of the process is the pres- .
is similar to tower 'I containing the reñuxing coil
ence of the so-called added hydrocarbon which,
i0 and reboiling coil 2l. It will be understood
that vin this >tower, the temperature is raised to 5 _ asstated above, should be a relatively stable ma- -' '
alkylated phenol and the distillation overhead not
only of the tertiary olenns but also of the added
terial boiling conveniently above >the boiling .
range of the feed stock and ., below the 4phenolic
material so that it may be on the one hand readily
hydrocarbon. The vaporized substances removed
separated Vfrom the unabsorbed constituents of>
a sufficient point to cause the _dealkylation of the
by a pipe 2| and discharged into a secondary lo’the feed stock by the first distillation step and
from the regenerated tertiary olefin and likewise
tower 22 which is similar to thoseshown above
readily separated from the phenolic material in
and is devised to make a close fractionation be
tween the tertiary olefin and the higher boiling ‘
added hydrocarbon. The tertiary oleñn is taken
overhead by a pipe 23, is condensed in 24 and 15
the regeneration step. When isobutylene is re
covered from Ct cuts, pentane is an admirable
material to employ but other materials may be
used as well, for example hexane, di-isobutylene
and other equivalent materials.A The added hy
drocarbon is preferably added at the inlet' of the
collected in 25. It is withdrawn as a liquid by a
pipe 28. The added hydrocarbon is withdrawn
from the base of tower 22 >by a pipe 21 and is
passed by a pump 28a for recirculation. It is~ ' 'absorber 4 so that it may be. present during the
preferably joined by the'stripped phenolic mate~ 20 absorption. When so used it tends to slow down
the alkylation reaction, making the control easier,
rial from tower il which is added by pipe 20 and
the mixture formed by the materials .ñowing a and tends to prevent excess polymerization of the
C4 oleñns. It mayfhowever, be added to the re
through pipes 21-and 28 then passes'through the`
action mixture iust after the absorption is com
heat exchanger il; through a cooler.” and by a
pipe 30 back to the leader 4a and the absorber 5. 25 plete. The amount of the added hydrocarbon
>can be varied over quite a range. say from 10 to
100%, by volume, based on the amount of phe- f
A\’I'h\xs it will be seen that the phenolic material,
the added hydrocarbon andthe alkylation -cata.
- lyst are continually circulated through a, closed
system and used over and over again to _treat
nolic material, but from «i0 to 60% is generally '
quite satisfactory.
fresh quantities of the C; cut which is,continually o After' the absorption _is complete, the first step
is the distillation of the normal oleflns and the
added and resolved into components consisting
. saturated hydrocarbons contained in the feed
on the one hand ofthe.- tertiary oleilns and on
the other of a mixture of oleflns and saturated C4V ’ stock. -This distillation is `carried out preferably
>under pressure so that the products may be col
e ¿In the operation of the present process, it will 35 lected in liquid phase without the use of refrig
eration and with the C4 cut this distillation may
be understood that the absorbent material is of a
be accomplished under super-atmospheric pres
phenolic nature. ,Phenol itself may be used for
, sure. say 40 to 60 pounds gauge. The'head tem
'this purpose or a cresol, or a mixture of cresols
perature `of the stillwill be about 43° C. and the
with or without other phenols. An advantageous
absorption medium consists of a mono-tertiary 40 bottom temperature about 82° C. .In any case,
the bottom temperature of this first distillation
phenol such as tert-butyl phenol -or tert-amyl
should not be above about 100" C., ,in order to
phenol. Simple phenol has been found capable
prevent a partial dealkylation and loss of the
of readily absorbing three molecules of iso
butylene and of readily evolving two molecules
tertiary olefin.
'I'he residue from the first dis- l .
thereof so that in eifeet _even when operation is 45 tillation consists of the phenol-tertiary oleiln
begun with simple phenol after a while`the ab- „ alkylate, the acid catalyst and the added hydro- „
sorption medium is largely mono-tert-butyi
carbon and this mixture, which forms 'a single
phenol‘which has proved to be a very satisfactory
» phase, is passed into thesecond distillation col
umn or 4the regenerator. Thisdistillation column
modo o1’ operation. If dealkylation conditions
maintained are'sumciently drastic, however. all to ls‘nkewise preferably held under pressure and
terials Vduring absorption are maintained, as indie
the temperature is raised sufficiently high'to not
only cause the dealkylation of thephenol but
also to distill olf not only the tertiary olefin but
cated above, preferably in the liquid phase at
likewise causethe distillation of the addedhy
tert-butyl _groups can be remov
and the mono
butyl phenol converted back to henol. è' The ma
.temperatures between about 60° and 100° C., and 55 drocarbon. The actual temperature therefore
\ a complete absorption of the tert-oleiin. can’be. _depends on the boiling` point of the added hydrocarbon, the “extent of alkylation ofthe phenol
accomplished in from 201:0 120 minutes, depend- V
andbther conditions. `With pentane and using
ins on the amount of tert-olefin in the feed.v
stock, -the’ratio of absorption agent to the feed ' a` pressure of say 50 to "I0 pounds gauge, the
l stock and other ponditions. It is found desirable' .o
- to provide about ¿33 to 1.0 mois of phenolic mate
~rial for each mol of iso-oleñn to be absorbed al- ' l.
though even‘ higher ratiornjxay be used. The ,
v alkylation d_ealkylation catalyst is .preferably a
maximum temperature will be about 250°
C. .4 -
When working at lower pressures, below 50
pounds. lower temperatures. in therange of 150
to 200° Cfare adequate. In cases where the
phenol is combined with 2 to 3 molecules of ole- l
mineral acid, suchfas concentrated sulfuric or c5 iin in the absorption step. regeneration tempera
.concentrated phosphoric acid,` but bther acid re'
tures as low as 100 to.110' C.' sumce at pressuresA
close to atmospheric._ The added _hydrocarbon
rapidly sweeps the tertiary olefin out of the phe
_ate or _
pho'sphatemay alsobe used,- as well _as benzene or
` :acting catalysts such as potassium acid-
nolas soon as it is released and prevents loss
amount of the alhlation'catalyst is small indeed. 70 on the one hand from incomplete dealkylation
phenol-sulfonic acids or some of their salts. The ,
for example from 0.1 t6 `i0 mol per cent' thereof
` based _on -thejphenol or equivalent material em
ployed, _and with otherwise` good conditions about _
one `mol'per> cent of’the _catalyst _is quite effective
- and on the other‘from polymerization during the
regeneration step.
~ '
‘ The third Fdistillation step is also preferably
_ accomplishedunder pressure vso aste permit the « .
_ in quickly effecting theaikylationof the'phenolic 7e tertiary olefin to be eollectedin liquid phase at
cooling water temperature. In this last still, the
separation is made between the tertiary olefin
and the added hydrocarbon and from the nature
of the separation required, it will be readily un
derstood that the added hydrocarbon should con
veniently boil above the boiling point of the tert
oleñn to be segregated. 'I‘he closer the added
hydrocarbon boils to the tertiary olefin the more
diillcult this separatio-n will be.` In any case, a
mixture of the phenolic material removed from
tower i8 and the added hydrocarbon taken from
tower 22 are returned or recycled for furtherV
reaction. As indicated before, the phenolic nia
terial which also contains the alkylation catalyst
_ «
-olefin and a dealkylated phenolic material, while
in thepresence of an added hydrocarbon having
`a boiling point between that of the tertiary olefin
and lthe phenolic material', andV also in the pres
ence of an acidic dealkylation catalyst, whereby~
the tertiary oleiin and the added hydrocarbon are
distilled. from the dealkylated material, and sep-v
arating the tertiary olefin and the added hydro- _
carbon- by fractional distillation.
3. Process »according to claim 2 in which the
added hydrocarbon is employed in an amount. of
10 to 100% of the volume of the phenolic ab
4. An improved process for recovering tertiary
is returned to the inlet of the reactor 4. The" 15 oleflns from hydrocarbon> mixtures >of similar boil
added yhydrocarbonis also preferably returned Íto ' ing range containing tertiary olef'lns which com
prises admixing with the hydrocarbon feed a
the same point but may be returned to the inlet
phenolic material- and, a minor amount of an
of the heating coil 6, if desired.
alkylation'.catalyst,- whereby the tertiaryolefin
As a specific example of the operation of the
process, a mixture of meta and para cresols and 20 alkylates the said phenol, distilling ofi the un
alkylated hydrocarbons contained, in the feed
a C4 cut containing 18-l`9% isobutylene was con
stock ata temperature below that at which de*
tinuously fed into and through a steel reaction
alkylation takes place, and while in the presence
drum at 85 to 90° C. -Pressure sufficient to main
«f tain the reactants in liquid vphase was provided ' of> an added hydrocarbon boiling between the
and the reactor was of size to give a time of125 tertiary olefin and the phenolic material, lregen
throughput of about 1 hour.
The mixture i'ed -
consisted of 5 mols cresol to 1 more ofisobutylene
and about .2 mol per cent of cresol sulphonlc acid
- based on the cresols was included in the feed.
As the reaction mixture emerged from the
chamber it was continuously admixed with onef
half of its value of mixed -pentanes and this .
mixture sent to a distillation towerwhich was
under 3 atmospheres pressure (abs.) and distilla
tionof the C4 hydrocarbon was effected using a
1' maximum temperature 'of 95 to 100° C. Practi
cally no decomposition of the alkyl phenol was ‘
noted during this distillation.
The debutanized mixture was now distilled
in a regeneration tower with a maximum tem
perature of 200° C. and under atmospheric pres
sure. From the top of the tower 'a mixture of
pentane and regenerated isobutylene was recov»
eratingpthe tertiary olefin by heating the tertiary
alkylated phenol to a dealkylating temperature
and distilling the tertiary olefin and the'added
hydrocarbon from the regeneratedphenolic ma
teria-l, then separating theregenerated tertiary
oleñn from the added hydrocarbon by fractional
distillation and returning the phenol and the hy
drocarbon for reuse.
5. Process according to claim: 4 in 'which theadded hydrocarbon is >a saturated hydrocarbon
and it is present during, the alkylation step.
~ 6. _Process according to claim 4 in which the -
added-hydrocarbon is asaturated hydrocarbon
and it‘is added to the alkylation product.
7. An improved process for recovering isobutyl- -
ene from its mixtures with other C4 hydrocarbons
which comprises agitating the C4 hydrocarbons in
the liquid phase with- a phenolic absorbent and
a small amount of an alkylation catalyst While in
ered while the regenerated cresol and catalyst
were drawnvoff of the tower from the bottom and ß. the presence of an addedhydrocarbon having a
boiling point between that of the C4 hydrocar
reused for further absorption of isobutene. .The
bons and the phenolic absorbent, whereby the iso
regenerated isobutene and the pentanes were
/ butylene is chemically combined with the phenolic
separated'by distillation and the pentane reused
as before. A careful balance showed that 93.7%`-v y absorbent 4to'i’orm an alkylated phenolic product, '
distilling the uncombined C4 hydrocarbons origg
of the isobutene fed tothe system was recovered .
inally >in the feed at atemperature below that at '
and the product contained 97.2% isobutene.
which dealliylation-tak'es place, heating the al
The present invention is not to be limited to
kvlated phenolic product while still -in the pres
the 'segregation of any particular tertiary olefinA
en-ce of the added hydrocarbon and the alkylation
nor to the use of any particular phenolic mate
catalyst to a temperature between about- 100° and
rial nor to any particular alkylation catalyst or
250° C., whereby _the phenolic substance is de
-added hydrocarbon, but only to the following
alkylated, removing. the regenerated tertiary
claims in which it isdesiredto claim ali novelty
butylene and the added hydrocarbonas vapors
'inherent in the invention.
from the phenolic absorbent and separatingv the
‘ We claim:
isobutylene' from the added hydrocarbon by frac
1.- An improved process for recovering tertiary
tional distillation, `collectlng` the isobutylene and
olefin from tertiary alkylated phenolic material,
which comprises heating >the alkylated material in
order to produce thetertiary olefin and produce'a
Adealkylatecl material in the presence of an added
hydrocarbon having a boiling temperature be,
tween thatA of the olefin recovered and the dealkyl
.ated phenolic material, whereby the tertiary olefin and the added hydrocarbon are distilled from the
dealkylated phenolic materiahand thereafter sep» ..
arating the tertiary oleñn andthe added hydro'-._ carbon by fractional distillation.
_2. An improved process for recovering tertiary
olefins from an alkylated phenolic material, which
comprises heating 'the alkylated material to a
dealkylating temperature to produces. tertiary
recirculating the said added hydrocarbon along
with the phenolic absorbent to the process.
8„Process according to claim 7A in which the ,
phenolic solvent is mono-tertiary butyl phenol.
9.» An improved lprocess for recovering tertiary
amylenesv from their mixtures with other C5 hy
drocarbons which comprises'agitating the Ca hy
drocarbons in the liquid phasewith a phenolic
absorbent,v and a°small amount of an alkylation
catalyst while in the presence of an added hy
drocarbcn' having a boiling point between that of
the C5 hydrocarbcnt and the phenolic absorbent.
.whereby the tertiary olefins arevchemically com
bined with the' phenolic absorbent to form an
alkylation prodiict, distllllng the uncombined Cs
hydrocarbon a's‘vapors from the~~ phenolic absorb-
ent and separating the tertiary amylenes from
ture below that at which dealkylation takes place,
the added hydrocarbon by fractional distillation.
heating the alkylated phenolic absorbent while
collecting the former and recirculating the latter
_still in the presence of the added hydrocarbon and' 5 along with the phenolic absorbent to the process.
the alkylation catalyst to a temperature between
' 10. Process according to claim 9 in which the
. hydrocarbons originally in the feed at a tex?pera
_ about _100° and 250° C., whereby the phenolic sub
stance is dealkylated producing tertiary amylenes
and a dealkylated phenolic absorbent, removing
the regenerated tertiary amylenes and the added l0
phenolic absorbent is mono-tertiary amyl phenol.
mma w. swarmï.
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