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Oct, 22, 1946.V
.Filed Jan. 30, 1942
Patented Oct. 22, 1946
Grant C. Bailey, Bartlesville, Okla., _assignor to
Phillips Petroleum Company, a corporation of
Application January 3o, 1942,seriá1`N0.4'2s,966
5 Claims. (Cl. 26o-683.15)
'I‘his invention relates to the catalytic poly
merization of mono-oleñns, and more particularly
tothe production of tetra-isobutylene from iso
butylene and di-isobutylene.
Tetra-isobutylene is a mono-oleiin containing
16 carbon atoms per molecule. Tetra-isobutyl
ene exists in several isomericY forms possessing
highly branched carbon structures and each
In the direct polymerization of an oleñn to a
polymer having a desired molecular Weight, such
as the polymerization of isobutylene to tetra-iso
butylene, for example, polymers of both higher
and lower molecular weight are formed. For any
given catalysts,V conditions can be found which
structure possesses an active olefinic bond mak
give an optimum yield of the desired polymer,
but the higher and lower polymers Will be pres
ent in lesser, but substantial amounts.
ing it useful in the preparation of chemical de
rivatives of this particular oleñn species through
gives the product analysis of the liquid obtained
various'reaction procedures. Hydrogenated tetra
isobutylene possesses a high octane number, mak
from a run in which gaseous isobutylene was
polymerized over activated fioridin at room tein
ing it useful as fuel of very low volatility inin
ternal-combustion engines. It has a solidiiying
temperature below _100° C., making it useful
at very low temperatures as a hydraulic fluid,
for example. In many such applications, it is
desirable to usea product having a particular
molecular weight and boiling range, together with 20
unique characteristics as previously suggested;
tetra-isobutylene is especially suited for some of
these applications.
The catalytic polymerization of mono-oleñns
` This is illustrated by the data in Table I, which
Table I
` Per cent of total liquid
Di-isobutylene ____________________ _-
Tri-isobutylene ___________________ __
Tetra-isobutylene _________________ __
« Penta-isobutylene _________________ __
~- Hexa-isobutylene
_______ „_ ________ __
Residue __________________________ __
to higher-molecular-weight products is Well
Isobutylene is one of the most reactive
mono-olefins, and its polymerization using vari
ous catalysts and conditions and its polymeriza
________________ __
Orthophosphoric acid also readily polymerizes
The productv which was . obtained
when isobutylene was polymerized with ortho
tion products have been the subjects of many in
vestigations.V These products range from di-iso 30 phosphoric acid at 30° C. comprised essentially
di- and tri-isobutylene, while at 130° C. seven
butylene, which is in the boiling range of gasoline,
isomeric polymers were produced.
through oils, to viscous, rubber-like, and non
Sulfuric acid readily brings about the poly
elastic resinous products. In any given reaction,
.merization of isobutylene to products containing
the product usually contains a series of polymers
of different molecularn Weights, each successive 35 di-isobutylene, tri-isobutylene, and higher poly
mers. At relatively low temperatures and loW
chance in molecular weight corresponding to one
molecule of monomer.
The average molecular
acidv concentrations, relatively high proportions
of dimer are produced. As the temperature and
weight of a polymer'product depends upon the
acid concentration are increased, the proportion
catalyst and the polymerization conditions. Us
ing highly active catalysts, such as aluminum 40 of higher-molecular-weight polymers, trimer and
tetramer especially, and the complexity of the
chloride, the proportion of products of different
polymer are increased. At still higher tempera
molecular Weights follows a probability distri
tures, the average molecular weight oi the prod
bution around the average molecular weight. In
such cases the average molecular weight is a
uct decreases, as a result of extensive changes in
the lower the temperature the higher the average
Metal halide catalysts, such as aluminum
chloride, boron fluoride, and the like, are very ac
function of the temperature of polymerization, 45 the hydrocarbons during polymerization.
molecular weight.
In many‘cases where the polymerization cata
tive, bringing about the rapid polymerization of
isobutylene to relatively high-molecular-weight
lyst is less active, such a probability distribution
is not found. The rates of the formation of vari 50 compounds. At temperatures of -80 to _100° C.,
isobutylene is converted to resinous or plastic _
ous polymeric `formsmay vary so greatly with
polymers of very high molecular weight. At 80°
temperature that true equilibrium conditions are
C.,`the polymer product contains oleiins ranging
never attained and the composition of the prod
from gasoline to lubricating oils, or dimers to
uct depends upon the comparative rates of the
55 decamers and sometimes higher. With increase
competing reactions.
in temperature of reaction, there is produced a
decrease in the average molecular weight of the
product and an increase in the complexity of the
polymer or in the other reactions accompanying
simple polymerization.
In all such catalytic polymerization systems,
acid of such strength can be used to selectively
absorb isobutylene from a mixture of normally
gaseous hydrocarbons. Upon heating such a sul
furic acid extract to about 100° C., isobutylene is
polymerized to a product containing 80 per cent
or more di-isobutylene.
one polymer is often produced in somewhat
When the hydrocarbon
stock charged through conduit H is rich in iso
butylene, treatment in polymerization unit l2
higher proportion, but always with substantial
amounts of polymers of higher and lower molecu
lar weights accompanying it, The preparation of
a product containing only trimer or only tetramer
is thus not'possible in the conventional polymeri
zation system. However, it has been found pos
sible by proper selection of 'a catalyst and a reac
tion system to limit markedly the reaction so that
dimer alone is produced in high concentration.
Two factors contribute tohi'gh maximum yields
with sulfuric acid as described will convert iso
butylene to a product containing more than 90
per cent di-isobutylene.
I have -round that good yields of di-isobutylene
can also be obtained from isobutylene by treating
an isobutyle'ne-containing mixture with phos
phorus pentoxide catalyst in the ytemperature
range of about -5 to +15° C. and preferably
from (l to ’10° C. As-the temperature is decreased
of dimers as contrasted to the lower »maximum
below _5° C., the rate of polymerization of iso
yields of any higher-molecular-weight product.
bu'tylene to di-isobutylene decreases very rapidly,
Firstly, there is no polymer having a molecular 20 and as the temperature of polymerization is in
weight ‘lower than the desired product. 'Sec
creased above 15° C., the ‘proportion of dimer in
ondly, the conversion Vto each successively higher
_molecular-weight vpolymer requires greater cata
jlyst activity than the previous conversion.
the Iproduct decreases rapidly, trimer becoming
the main product. Using polymerization tem
Therefore, careful 'selection of catalyst and con- ,
‘ditions minimizes the'formation ‘of 'higher poly
peratures in the range of 0 to 10° C., 50 to'60 per
cent yields of dl-isobutylene can be obtained.
«Elñuent from polymerization unit E2 is passed
through conduit £3 controlled by valve -35 to sep
arator id. Any unreacted isobutylene in the ef
íiuent from unit 'l 2 is >separated therefrom in sep
mers. Several combinations of catalysts and con
ditions have >been found by various workers
whereby di-'isobutylene can be prepared from iso
`butylene in yields ‘of 80%-01‘ greater.
arator i5 and passed through conduit l5 con
>I have 'now found that `di-isobutylene can 'be
trolled by valve S6 to‘conduit AIl and thence to
converted'to tetra-‘isobutylene in high yields using
polymerization unit l2. When material lower
boiling 'than isobutylene is charged to my process
through conduit VH and is substantially inert
under the conditions `in unit I2, such material
4phosphorus pentoxide ’as 'a catalyst. This ‘inven
tion affords a method of converting isobutylene
to tetra-isobutylene in high yields and more
`readilythari was previously possible. This is ac
complished by using a two-step process compris
is removed from'separator 'ifi and from my proc
ess through conduitsfbll and i6 controlled by valve
3l. When 'it is desirable to have such material
ing polymerizing isobutylene to di-isobutylene
under conditions that produce high yields >of di
present during -the conversion of isobutylene in
unit i2, 'it can be >recycled ‘from separator I4
‘through conduits "54 and l5 controlled by valve
isobutylene, separating this dimer from other
products and converting it »to tetra-isobutylene
'usingrphosphorus pentoxide asä catalyst.
38, when‘valve v3'! inßconduit lß’is wholly or‘partly
ìIt is an object of my invention to convert'a low
`boiling olñn to a higher-boiling olefin.
closed. Tri-isobutylene produced -in unit `I2 is
removed from separator Ylil through conduit 58
controlled by valve 63 and‘may be lfurther treated
` Another object of my invention is to produce
an olefin polymer having a desired molecular
`as appears desirable.
Usually I prefer to pass
'weight in high yields íroman oleñn'of Vlower'mo
such `trimer material ¿to depolymerization unit
lecul'a'r weight.
‘|9, the operation of which is subsequently de
fAno'th‘e'r object is to -rapidly polymerize a
scribed. -Sometimes minor amounts of tetra
mono-oleñn to a lpolymer of desired molecular 50 4isobut'yleneare also Aproduced'in unit l2 and such
vweight 'in high yields.
material lmay be removed from separator I4
Another object is ’to produce high yields of
>through `conduit "Se controlled by valve fS5 as a
desirable product of my process.
Further objects and advantages of my inven
Polymeric `Vhydrocarbons boiling above the
tion will’be apparent from t‘heaccompanying dis- ` '
tetra-‘isobutylene range `are ‘removed -from sepa
rator |11 through‘conduit l? andywhen such ma
My invention'will now be more particularly de
erial is considered as undesirable in my process,
scribed and 'exempliiied in connection with the
it can be removed therefrom through conduit I8
drawing'which is a schematic flow-diagram illus
controlled by valve 39. When, however, such
trating specific embodiments of the’invention Vfor co high-boiling polymeric ‘hydrocarbons can be de
the production of high yields of desired polymeric
polymerized to useful materials, for example, they
hydrocarbons lfrom monomeric hydrocarbons.
are passedthrough valve ’llû'in conduit kI'l to de
Isobutylene, or a 'hydrocarbon mixture con
polymerization unit I9 when valve '39 in conduit
taining essentially'isobutyle'ne and other hydro
>I3 is 'wholly or `partly closed. In unit i9 such
carbons -substantially inert under theconditions ‘
polymers along with any trimer or tetramer
at which isobutylene is subsequently converted,
passed thereto are depolymerized under suitable
is'passe'd’through conduit ll controlled by valve
‘IU to >polymerization unit l2, wherein isobutylene
is 'treated yaccording to any of the processes'well
known in the art for the production therefrom of
di-‘isobutylene in optimum yieldswith only small
amounts of other polymeric hydrocarbons being
produced. Sulfuric acid having a strength be
tween ‘60 and 75’per cent is a particularly advan
tageous-catalyst'for'such a conversion. -Sulfuric
conditions of temperature, pressure, and'reaction
time, in the presence or absence of catalytic ma
terials for .promoting depolymerization Vreactions
to produce monomeric oleñns that can be ad
vantageously used, such Vas isobutylene, tetra
isobutylene and even ole’ñn hydrocarbon poly
mers in the lubricating-oil range.
The de
polymerization of high-molecular-weight ole
1in polymers to lower-molecular-weight hydro
mospheric pressure is usuallypreferred in opera
carbons is well known.,` Such depolymeriza
tions result in the regeneration of the original
tionsi of this kind at the lower temperatures,
althoughhigher pressures can be used to advanl-j
tageand pressures as high as 1000 pounds per4
square inch gage produce desirable results. The
reaction time for carrying out this `polymeriza
olefin from which the polymer was prepared to
gether with low-molecular-weight 1 . olefin@` poly
mers, such as >those in the gasoline boiling range.
In these depolymerizations, negligible amounts
tion step is -preferably in the range between three
hours Jand seven hours although reactionptimes
Generally, the amount of polymeric material
boiling above >di-isobutylene in the eiiiuent of
outside of this range have been found toV produce
polymerization unit l2 will be quite small, and all 10 substantial amounts of the desired product.
When short reaction times are employed in unit
such material may be charged to the depoly-`
25 at any giventemperature< Within the range
disclosed, less di-isobutylene is polymerized¢per
Eflluent from the depolymerization unit `I9 is
pass and, therefore, more di-isobutylene is re
passed through conduit >6E) controlled by valve 59
to separator 55. Inseparator 55iany low-boiling 15 cycled to unit 25 for further conversion to tetra
offcarbonaceous residues and hydrogen result.
isObutylene. Long reaction times in unit 25 favor
higher conversion per pass operation Vwith an
inherent less amount of recycle of unpolymerized
di-isobutylene to unit 25. However, prolonged
catalyst life and other factors may make it de
material having less than four carbon atoms per
molecule is removed from the system through
conduit 56 controlled by- valve 51. Usually the
amount of this material will be ‘very small and
generally negligible. Isobutylene contained in
>the effluent from unit i9 'i's'passed from separator
55 through conduit 2| controlled by valve 43 to
sirable'to work with short reaction times and less ,
polymerization per pass.
In unit 25 it is desirable to secure intimate.
conduit Il wherein it is admixed with fresh
contact between the phosphorus pentoxide .cat
charge stock to polymerization unit I2. A di-iso
butylene fraction, which will sometimes consti 25 alyst and hydrocarbon material.` To facilitate in
timate `mixing,fmaterials which aid in dispers?
tute an appreciable portion of the eflluent from
ing the phosphorus pentoxide may be used, such
depolymerization unit .l9,'is -removed from sepa
as sand or lamp black. Efficient contact between
rator 55 through conduit 22 and passed through
catalyst and reactants is highly important in the`
polymerization step in unit 25.
valve 48 to c‘onduit 24 and thence through valve
4l. to polymerization unit 25 subsequently de
scribed herein,
. The di-isobutylene charged to polymerization
unit 25 is preferably quite pure and particularly
Any hydrocarbon material having’ a higher
free from oxygen-containing compounds, such
boiling range than di-isobutylene and including
material in the lube-oil boiling rangewis removed
from separator 55 through conduit 20 y,controlled
as are readily formed when di-ísobutylene is eX
35 posed to air or oxygen. The presence of oXy
gen-containing compounds in the di-isobutylenev
by va'lve‘42.""Material‘boiling abovethe lube-oil
feed to unit 25 greatly decreases the rate of poly
merization therein and necessitates the use of
larger quantities of phosphorus pentoXide cat
alyst to produce satisfactory yields than when
suchu'o’xygen-containing ’compounds are absent
from unit 25.
range', including tars" ‘and high boilingundepoly
merized material from unit i9, is removed from
separator 55 through conduits 63 controlled by
valve 58. In somevinstances it will be. desirable
vto return material `removed through conduits 20V
and/or 53 to the depolymerization.unit> |91for.
conversion to additional quantities of di-isobuty-`
lene, either directly or indirectly, by means not..
Under the more favorable conditions discussed
herein the phosphorus pentoxide catalyst is not
shown inthe drawing. Such operation is par 45 rapidly deactivated. The useful life of the cat
alyst depends `upon the rate at which it is de
ticularly advantageous when-it is desirable` to
activated by absorption of water and the rate at
charge as much di-isobutylenetoV polymerization
which sludge-like materials are built up by reac-V
unit ‘25’ as possible.
l ~ ’ ~ ‘
substantially .fpure
tion with oxidized olefins or other reactive im
In polymerization0 unit .
di-,isobutylene ` is` contacted ‘with phosphorus. 50
herein. In some instances it will be desirable> to
charge di-isobutylene to my process from some`
or any other suitable means well known to the
outside source. This is conveniently done by
means of conduit 23` controlled by valve 41..
art, and is then recycled to polymerization unit
25 by conduit 30 controlled by valve 46. When
Phosphorus pentoxide ischarged to polymeriza
tion unit 25 through conduit 26 controlled by
valve 44. _It may, however, be admixedwith`
hydrocarbon chargefstock to unit _25 by means 60
not shown before said stock is admitted to unit
25 and under conditions which do not promote
appreciable conversion,Í of said hydrocarbon
charge. Inunit v25 phosphorus _pentoxide is con
:Effluent from polymerization unit 25 is passed
through conduit 2l .controlled by valve 451:0 sep
arator` 28. Phosphorus pentoxide `catalyst is re
moved from the-liquid by filtration, centrifuging,
pentoxide under conditions for the, productionbf
optimum yields of tetra-isobutylene as disclosed
used catalyst has become so spent as to be un
economical for conversion of additional di-iso-butylene, such spent material or> spent catalyst
is removed from my process through conduit 3l
controlled by valve 52 whereafter it may be dis
posed of or treated as appears desirable.
ally such‘spent material is regenerated to active
tacted with di-isobutylene charged, thereto‘in a 65 catalytic material and> recharged to unit 25 and/ or
to‘any other catalytic process or unit employing
temperature range between about 0° C. and*4 100°A
C. and underv a suiiicient pressure that the hydro
phosphorus pentoxide as a catalyst’.
carbon charge will be in the liquid phaser, Within
this temperature range the reaction is essentially
dimerization of diisobutylene. vNo polymers
higher-boiling’than tetra-.isobutylene are usually
dpi-isobutylene is separated and recycled to poly
merization unit 25 through line 29 controlled by
found in the product. Although the polymeriza- »
tion >reaction in unit 25 ,proceeds more `rap
idly‘at 'highertemperatures arange between>
aboutZO" C. and 60° C. is usually preferred. 'At
valve 49. Desired tetra-isobutylene is removed
from separator 28 through conduit 33 controlled
by valve 50. It is readily obtained in a state of
" high purity since no isododecene or iso-eicosene`
is produced by the polymerization in
ïthereby affording a simple separa-tion in separa-i
tor 28; During an extended operation of my
process small amounts of polymeric material
Table V
higher boiling than tetra~isobutylene maybe pro
Volume per cent
duced inunit 2-5 and can be removed from sepa
rator 28 through conduit 32 and from my process
through valve 5|. When such material is easily
Di-isobutylene ______________________ __
Tetra-isobutylene ___________________ __
depolymerizable to a-lower-molecular-weight pol
ymer such as di-isobutylene, or to isobutylene,
Examples III and IV show that phosphorus
pentoxideA polymerizes di-isobutylene to tetra-iso
it is preferably charged to depolymerization unit
I9»wherein a conversion is carried out as described 10 butylene over a wide range of temperature and
My invention is furtherillustrated by the fol
that the reaction proceeds more rapidly at higher
temperatures than at lower.
lowing examples which are recorded to disclose
specific applications of my invention and are not
intended to limit unnecessarily the scope or util
ity of the principles of my invention in anyway.
Twenty parts by weight of freshly prepared di
isobutylene and 1 part phosphorus pentoxide
were agitated at room temperature for 4 hours.
The product was filtered and distilled. The fol
lowing composition was found:
A steel pressure autoclave which was equipped
with an eíiìcient stirrer and an internal thermo 20
Table VI
couple was thoroughly cleaned and dried using
a stream of dried nitrogen. Phosphorus pen
Volume per cent
toxide was introduced into the autoclave under
Di-isobutylene ______________________ __
anhydrous conditions.
Tetra-isobutylene ___________________ __
A charge stock consist
ing of 76 per cent isobutylene and 24 per cent 25
isobutane was forced into the autoclave during
a 5-hour period. The autoclave was cooled with
ice, and the charging rate adjusted so that the
internal temperature was held between 0 and 2° C.
The unreacted isobutylene and isobutane were re
The run cited in Example V was repeated using
di-isobutylene which had become partially oxi
dized by contact with air. The product had the
leased from the reactor, and the polymer prod
uct filtered and fractionated. The product hadv
following composition:
the following composition:
Table VII
Table Il
Volume per cent
Di-isobutylene ______________________ __
Tri-isobutylene ______________________ _ _
Tetra-isobutylene __________________ ___
polymers ________ ___ ______ _____
Volume per cent
Dl-isobutylene ____________________ ___
Tetra-isobutylene __________________ __
Examples V and VI show that, in order to pro
duce high yields of tetraisobutylene from di
isobutylene using phosphorus pentoxide, the di
isobutylene must be substantially free from oxi
dation products.
The run cited in Example I was repeated except
the temperature of the reaction was held at about
35° C. Fractionation of thev product showed it
to >have the following composition:
of> my process may be found desirable in connec
Many variations in the apparatus or operation
tion with specific embodiments and various modi
ñcations may be readily made by one skilled in the
artI in the light of the present disclosure. The
Table III
`various polymerizationu steps may be operated
Volume 17ery cent
Di-isobutylene ____ __ ________________ ___
Tri-isobutylene ____________ _____________
Higher polymersl _______________ ________
continuously or intermittently in batches as may
be found most desirable for any particular case
and-f the particular conditions used. The drawing
is, ofcourse, diagrammatic and the application
y of my invention on a commercial scale will neces
sitate the use of much equipment such as pumps,
heaters, coolers, fractionators, and the like not
shown in detail but. which may be readily applied
and'adapted for any particular installation by one
159‘C. for seven hours. The catalyst was removed 60 skilledin the` art. separators, such as I4 and 28,
willv advantageously comprise several individual
by ñltration, and distillation of the product
units such as ñlters, fractional distillation col
showed it to have the following composition:
umns, strippers, accumulators and the like equip
Table IV
ment well known in the separating art. The gen
Volume per cent
eral process and possible material flows have
Di-isobutylene _________________ _____ __
16 .
been disclosed and this together with the specific
'I‘wenty parts by weighty ofv di-isobutylene and l
'part phosphorus- pentoxide were agitated at lll-'
Tetra-isobutylene _______________ ______
examples are .believed tok be suñicient to Serve as
efficient guides.
Twenty parts by weight of di-isobutylene andîl
part phosphorus pentoxide were contacted at 100‘."
C. for 3 hours. The material was cooled, filtered
and distilled. The liquid. product had the follow
ing composition:
I claim:
l; A process for producing high-boiling hydro
carbons from lower-boiling hydrocarbons, which
comprises passing di-isobutylene to a polymeriza
tion zone and contacting said di-isobutylene in
the liquid phase in said zone with phosphorus
pentoxide at a temperature between 0° C. and
100° C. for a period of time such that an optimum
amount of tetra-isobutylene is produced.
2. The process of claim 1 wherein the reaction
time for the polymerization is between three and
seven hours.
3. In a process for producing high~boiling hy
drobar-bons from lower-boiling hydrocarbons, the
tetra-isobutylene, and removing said fraction
from the process.
4. A process for the production of tetra-iso
butylene by polymerization of di-isobutylene
Without the formation of substantial amounts of
tri-isobutylene, Which comprises subjecting di
isobutylene in the liquid phase to the action of
phosphorus pentoxide at a temperature within
polymerization zone, contacting said di-isobuty
the range oi approximately 0° C. to approxi
lene in the liquid phase in said zone with phos 10 mately 100° C‘.
phorus pentoxide at a temperature between 0°
5. A process for the production of tetra-iso
steps which comprise passing di-isobutylene to a
C. and 100° C. for a period of time such as an op
timum amount of tetra-isobutylene is produced,
passing eñiuent from said polymerization zone
butylene by polymerization of di~isobutylene
without the formation of substantial amounts of
tri-isobutylene, which comprises subjecting di
to a separating means, separating therefrom a 15 isobutylene in the liquid phase to the action of
fraction rich in di-isobutylene and returning said
fraction to the polymerization zone, separating
also therefrom a fraction comprising essentially
phosphorus pentoxide at a temperature within
the range of approximately 20° to approximately
60° C.
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