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Jan. 7, 1947.
F. E. #Rl-:Y
2,413,759
ALKYLAT ION OF PARAFFINS
Filed Jan. 8, 1940
SNVEN.
EJNI .LVNOILDVHJ
FMOUTELR.
30
SNVBW
RECYL
SNLLVBVdÈS
AHLKIYDE
HOLVWAN‘IV
2
4
PARFIN
3
HALKIYDE
-
l
INVENTOR
FREDERICK ' E . FREY
AT TORNEYS
Patented Jan. 7, 1947
' 2,413,759'
UNITED lsTATEs PATENT OFFICE
2.413359
ALKYLATION 0F PARAFFIN S
Frederick E. Frey, Bartlesville, Okla., assigner to
Phillips Petroleum Company, a corporation of
Delaware I
Application January 8,1940, serial »10.312.964
11 claims. (cuzco-essa)
l
of paraf'flns by alkyl halides.
2
primary alkylation product appears to undergo
This invention relates -to the alkylation of
parafiins, and more particularly to the alkylation
secondary reactions that form lower-boiling and '
’
higher-boiling products; it doubtless also under
'
goes isomerization.
I have found that alklation of parañlns by alkyl
The reaction appears to proceed most efllciently
halides may be effected efficiently in the presence
for isoparaillns, especially those having four to ‘
of concentrated sulfuric acid at ordinary tem
eight carbon atoms per molecule,v and for non
peratures. -I have also found that sulfuric acid
primary alkyl halides in which the alkyl group
containing a low concentration of aluminum sul
has three to six carbonatoms. Of the non-pri
fate as a promoter is a good catalyst for such
alkylations. I have further found that the alkyla 10 mary alkyl halides, the tertiary react somewhat
more rapidly than do the secondary; hence, if a
tion reaction is favored by the paraffin having a
secondary alkyl halide is used, it is advantageous
branched structure with a tertiary hydrogen, and
'
by the alkyl group being non-primary, that is,
to use -a relatively high strength of acid, such as ‘
parañlns, especially of lower-boiling isoparafilns.
saturated, and have excellent anti-knock ratings.
100 to 105 per cent sulfuric acid.
secondary or tertiary. Furthermore, I have found
Fluorides, chlorides, bromides, and iodides mayv
that chlorides are somewhat more advantageous 16
be used, but bromides and especially iodides have '
than other halides for the alkylation of parafiins.
a marked tendency to reduce the sulfuric acid,
An object of this invention is to effect the \
and for this reason, and for economic reasons, it
alkylation of parafñns to form paramns having a
is preferable to use the chlorides. The products>
higher molecular weight.
.
Another object is to effect alkylation of par 20 formed when a propyl or butyl chloride is re
acted with isobutane or isopentane boil chiefly in
aillns with alkyl halides.
.
the gasoline range, are substantially completely
-Another object is to decrease the volatility of
The reaction is favored by a high ratio' of
paraffin to alkyl halide; for this reason the alkyl
halide advantageously may be added intermit
Another object is the production of isoparaf
fins having aA desired and previously selected
molecular structure.
`
tently or portion-wise, as taught >.for oleñns in l -
Other objects and advantages of the invention
the Frey Patents 2,002,394 and 2,104,296.
will be obvious to those skilled in the art.
The invention will be readily- understood from
The reaction is also favored by a relatively high
hydrocarbons boiling in the motor-fuel range.
A feed stock comprising chiefly Aat least one
vantageously within the range of 0.5 to 1. If
desired, the acid may contain a promoter, such as
the following description and the accompanying 30 ratio of sulfuric acid to hydrocarbons; the acid
preferably should have alvolume within the range
drawing, which shows a flow-diagram for a pre- 0.1 to 2 times the volume of hydrocarbon, ad
ferred mode of operation adapted to produce
Y paraffin entersthe system through inlet I hav
ing control-valve 2. Another feed stock, com
prising chiefly at least one alkyl halide enters the
system through inlet 3 having control-valve 4.
silver sulfate, aluminum sulfate, and the like,l
35 4preferably
in relatively low concentrations, such
as from 0.5 to 5 per cent by weight.
Intimate contact between the sulfuric acid andv
the alkylation reactants is essential. This pref'
tinuously or intermittently. The two feed stocks 40 erably-is obtained by vigorous mechanical stirring
or mixingand by the vpresence of an adequate
are intimately mixed with each other and with
amount of acid. It also may be promoted by
concentrated sulfuric acid in alkylator 5, as by
the presence of certain emulsiilers in the mix
vigorous mechanical stirring. The sulfuric acid,
which enters alkylator 5 through inlet 6 having f ture, such as, for example, alkyl sulfates. As
control-valve 1, may have a strength within the 45 alkyl sulfates or equivalent- compounds are
formed to some extent during the reaction, a
range 90 to 105 per cent by weight, preferably
small proportion of spent acid advantageously
between 96 and 102 per cent. Under the influ
may be added to fresh acid to increase its ability
ence of the sulfuric acid, the paraflìns are al
to emulsify with the alkylation reactants.
kylated ,by the alkyl halide, forming less volatile `
paraiilns. The reaction temperature may be in 50 Like all organic reactions, the alkylation of
paramnswith alkyl halides requires some time to
the range 0 to 125° F., preferably about 70° F.
` approach completion. Generally a reaction time .
Various reactions occur in alkylator 5, but the
between 5 minutes and'3 hours is adequate; much
primary reaction is believed to be alkylation of
-Either or both feed stocks may be added con- '
longer periods preferably should be avoided, as
paramns, especially isoparafilns, which are al
kylated more easily than normal parafñns. The 55 they favor secondary reactions that convert the
3,418,759
progress of the reaction may be obtained from the
rate of evolution of hydrogen halide, which is
2- and 3-methylhexane, 2,3- and 2,4-dimethyl
pentane, and `3-ethylpentane, and the like. The
isoparaillns produced generally, .although not nec
a Lby-product ,of `the primary reaction; the hy- .
drogen .halide advantageously may be removed
and used for the manufacture of additional alkyl
halide.
After -a `suitable reaction time, the mixture of
essarily always, will have a similar structure.
> When it is desired to produce a, gasoline, or some
certain valuable hydrocarbon or hydrocarbons
`boiling in the motor-fuel range, it will generally
hydrocarbons, sulfuric acid, and by-products, such
as hydrogen halide, is passed through valve .8
andconduit 9 into separating means III, in which
the sulfuric acid .is separated from .the mixture.
" not be desirable to use an isoparafiin of higher
molecular weight than isobutane or isopentane,
or possibly an isohexane. When it is desired to
The sulfuric acid .may be withdrawn through valve n
I-I and outlet I2, and thence `itmay be subjected
to a process of reclamation, if desired; or, alter
natively, if may 4bereturned, partly or entirely,
as is .desired yor .as trial indicates is desirable, _to
alkylator 5 through valve .I 3 and conduit Il. Hy
4
andthe like, that is, hydrocarbons which contain
at least one tertiary hydrogen atom. Other ex
amples oi! such hydrocarbons are the isohexanes
`2- and 3-,methylpentane, isoheptanes `such as
primary alkylation product into lower-boilingand
higher-boiling products. >Some indication of lthe
'
produce .higher-molecular-weight paramns, cor
respondingly higher - molecular - weight initial
paramns should be used as the charge stock.
It has been found that the more highly
branched isoparamns of higher molecular weight
somewhat readily decomposed by prolonged
drogen halide is’withdrawn through valve ISand ,20 are
contact with sulfuric acid, and when these >are
outlet I6,'and thence it'may be >used for the prep
used the reaction conditions should be so medi
>aration- of vadditional yalkyl halide. The hydro
iled, as indicated by trial, that extensive deleteri
carbonssare passed vthrough valve I1 and conduit
ous decomposition does not take place. For this
I8 yto alkali 4treater I9, in which any acidicmate
reason, it may at times be more desirable to
rial is removed by a treatment with an alkali, 2 5 charge a simple isoparailln such as Z-methyl
detailedequipment .for >this being within the skill
heptane or 2,4-dimethylhexane than la complex
isoparamn such as 2,2,4-trimethylpentane.
It will, of course, generally be impractical to
charge any particular hydrocarbon in an Vabso
0
erated; .undersuch conditions, if desired, at least
lutely pure state, especially when using higher
'part of the hydrocarbon material from separating
boiling hydrocarbons. When it is desired to pro
means »I Il may be passed through valve 23 and
duce particular individual paramns in a relative
conduits 24.1 and 2I -directly to fractionating means
ly
pure state, which can be readily puriñed by
22without being subjected to an alkali treatment
35 fractional distillation, the hydrocarbon mixture
in alkali ‘treater I9.
charged should be relatively free of readily reac
From alkali treater I9 the `hydrocarbons are
tive parañins other than the onenecessary to
passed through valve 20 and conduit v2| to frac
produce
the desired product. When isoparafilns
tionating means 22. In fractionating means 22,
are reacted, the presence of limited amounts of
the hydrocarbon material is fractionated into a
normal parañins is generally not deleterious, and
heavy-oil fraction, which is withdrawn through 40 may
at times be advantageous in controlling the
valve 125 and outlet 2B; into a gasoline or .motor-v
reaction.
At other times, less pure hydrocarbon
fuel fraction, `which is withdrawn through valve
fractions may be used.
.,
21 and outlet 28; .and vinto alight-hydrocarbon
As previously mentioned, it is preferable to use
fraction, which may be rrecycled to `alkylator i
through "valve .29 and'conduit '30, or may be dis 45 either ksecondary or tertiary alkyl halides, and it
is also preferable that the halides be chlorides.
charged .from the system, entirely or in part,
-of 4one versed in the art, and not shown. Under
some conditions cf operation, >a small amount of
.acidic material in the hydrocarbons .may be .tol
through valve 33 and outlet '34. This light-hy
drocarbon fraction ,comprises chiefly unreacted
The `alkyl halides having relatively lotv molecular
weights are generally readily obtained in a more
or less pure form, especially those having not
50
more than about six carbon atoms per molecule.
stock,‘the'lower-boiling alkylation products, such
Especially when it is desired to produce a gasoline,
as those .containing kup to .about seven carbon
such as aviation gasoline, or some certain valuable
atoms per‘molecule. If desired, .a light-gas irac-v
hydrocarbon or hydrocarbons boiling in the mo
ktion comprising chiefly paraillns having less than
tor-fuel range, it will be desirable to use such
'fourcarbon atoms per molecule, which are alky
lated less readily than heavier hydrocarbons, may 55 a low-molecular-weight halide in a pure state.
In any case in which such a particular hydrocar
be withdrawn through valve 3| land outlet 32.
bon product is desired, the individual paramn and
Unreacted alkyl halides may be removed through
alkyl halide suitable for forming it may be read
conduit .35 and valve 36, `or may be recycled, en
ily selected by trial, in the light of the present
tirely lor in part, through conduit 31 and valve
paraiiins land, if desired ‘when .used ‘as .a recycle
38 toconduit 3.
v60 disclosure. At other times, a more or less impure
-
It is to be understood, .in-connection with the
. foregoing process, that only the yprincipal steps
have been shownrand that mechanical details
of each step will be somewhat dependent on'each
adaptation kof my invention.
The separating
- means and fractionating .meansshown will com
prise separators, fractionators, pumps, tanks, coole
`ing and Aheating units, etc., and similar equipment
rwill -also be required for the other steps shown.
alkyl halide fraction may be used.
The temperature, reaction time, and relative
amount of sulfuric acid are interrelated. With
higher temperatures and/or larger amounts of
acid, shorter reaction times may be used. When
it is desired to produce a relatively pure product,
shorter reaction times and smaller yields per pass
should be used, and when a .certain appreciable
amount of side reactions, or secondary reactions,
Such equipment is of common knowledge, and 1 0 may be tolerated. the process can be so operated
as to have longer reaction times and higher yields
can be‘readily included by one skilled in the art.
per pass. The most desirable conditions in any
The `,term isoparafiln as used in_'this soeciñca
tion, in.connection with the charge'stock, refers
to parañin hydrocarbons such as isobutane <2
methylpropane), isopentane (2-methy1butane),
particular instance can be readily determined by
trial. When'sulfuric acid strength in excess of
7 Ul 100 per cent is mentioned, reference is made t0
anarco
furic acid was separated by settling, and the hy
drocarbon layer was freed from acidic material
by washing with alkali. Ofthe hydrocarbon ma
terial other than isopentane, 98 per cent by weight
so-called "fuming” sulfuric acid which. when
titrated with an alkali, reacts with sufficient
alkali to be equivalent to the amount of acid in
dicated.
v
boiled between 85 and 410° F.; this fraction, which
was completely parafilnic, amounted to 90 per
The following examples are given for the pur
pose of illustrating a few of the many possible
modes of operation of the process; they `are not
necessarily to be taken as establishing limita
tions of the invention.
‘
cent by weight of the theoretica1 yield based on ‘
the formation of nonane.
`
10
Example I
To a mixture of 500 cc. of 96 per cent sulfuric
acid and 359 grams of isobutane in a flask, which
was equipped with a reflux condenser and a mer
To a mixture of 180 grams of isopentane and
_500 cc. of sulfuric acid, which had a strength
`.of 102 per cent lby weight and which contained
2 per cent by weight of aluminum chloride, was
added 98 grams of isopropyl chloride during about
cury-sealedmotor-driven stirrer and which was
cooled to about 10° F., was added 185_ grams of
tertiary butyl chloride during about half an hour.
The reaction mixture was stirred vigorously dur
ing the addition and for about four hours there
after; the temperature .was kept below about 40° 20v
` F.
Considerable hydrogen chloride was evolved.
On standing, the resultant mixture separated into
an acid layer and into a hydrocarbon layer, which
i
Example V
half an hour. 'I'he mixture was stirred vigorously
during the addition and for about four hours
thereafter; the temperature was maintained at
68° F. 'I'he sulfuric acid was separated by set
tling; and the hydrocarbon layer was washed with
dilute alkali. Of the hydrocarbon material other
than isopentane, 98 per cent by weight boiled be
tween 85 and 410° F.; this fraction, which was
was removed and washed with dilute alkali. This ‘
completely paraillnic, amount to 80 per cent by
hydrocarbon layer was completely paraflinic and 25 weight of the theoretical yield based on the for
had a substantial content of hydrocarbons having
mation of octane.
more than four carbon atoms per molecule.
Example VI
Example Il’
To a mixture of 438 cc. of 102 per cent sulfuric
To a mixture of 500 cc. of sulfuric acid having 30 acid and 158 grams of isopentane was added 89
a strength of 102 per cent by weight and- 288
grams of isopropyl chloride during about half an
grams of isopentane, in a flask fitted with a reñux
hour. The mixture was stirred vigorously during
condenser and with a motor-driven stirrer, was
the addition and for about half anvhour there
added 160 grams of isopropyl chloride during
after; the temperature of the reaction mixture
about half an hour. The reaction mixture was 35 was 68° F. The sulfuric acid was separated by
stirred vigorously during the addition and for
about four and a half hours thereafter; the tem
settling, and the hydrocarbon layer was freed
from acidic material by a caustic alkali wash.
- perature was maintained at about 70° F. AfterI
After depentanization, the product contained over
the acid was separated from the resultant mix-_'
95 per cent of hydrocarbons boiling in the gaso
ture by settling, the hydrocarbon layer was freed 40 ,line` range, almost 'half boiling in the octane
from acidic material by washing with dilute
range. The yield of gasoline was 37 per cent of
alkali, and then it was fractionally distilled. The
the theoretical yield of octane; this yield is rela
material other than unreacted isopentane, and
tively smaller than those obtained in the preced
boiling from.85 to 410° F., amounted to 99 per
ing examples because of the relatively short time
cent by'weight of the total hydrocarbon product 45 of reaction.
‘
y and to 78 percent by weight of the theoretical
yield based on the formation of octane.
Example VII
f
Example m
y A liquid'butane stream,`comprisingy isobutane
To a mixture of 500 cc. of 96 per cent sulfuric
acid and 288 grams of isopentane, in a flask fitted
as the major'constituent, is mixed with about
one-third an equivalent volume of a »'material
'
with a reflux condenser and a motor-driven
stirrer, was added 185 grams of tertiary butyl
chloride during about an hour. The reaction
mixture was stirred 4vigorously during the addi
consisting principally bf isopropyl chloride. The
resultant mixture or blend, is continuously and
intimately. admixed, by a mechanical mixing
pump, with >one-half the equivalent-volume of
sulfuric acid having a strength of about 101 per
tio'n‘ and for about four hours thereafter; the
, cent, >and consisting of a blen/d of equal parts of
temperature was maintained at about 70° F.
fresh andrecycled acid. The resultant liquid
After the acid was separated from the resultant
mixture, or emulsion, is rapidly lpassed through
mixture by settling, the hydrocarbon laye'r was
-removed and freed from acidic material by wash 60 an elongated tube coil of restricted cross-sec
tional .area, which is immersed in a liquid bath
ing with dilute alkali. 0f the hydrocarbon ma
which removes heat and maintains the reaction
- terial other than isopentane, 96 per cent by
temperature below 80° F. The turbulence set up .
weight boiled between 85 and 410° F.; this frac
by the rapid flow through the tube coil aids in
tion amounted lto 83 per cent by weight of the
theoretical yield based on the formation of 65 maintaining an intimate mixture of the reac
tants. After a reaction time of about 10 minutes,
nonane.
the stream is passed to separating means, where
`Example IV
in the hydrocarbon material is separated from
the sulfuric acid material and from" hydrogen
To a mixture of 500 cc. of sulfuric acid having
a strength of 102 per cent by weight and 288 70 chloride. The free acid in the hydrocarbon ma
grams of isopentane was added 185 grams of sec
terial is«neutralized and removed/'by an alkali
ondary butyl chloride during about an hour. The
wash, and the stream is then passed to a series
mixture was stirred vigorously during the addi
of fractionators. 'In these fractionators there is
separated a butane stream containing unreacted
tion and for about three hours thereafter; the
temperature was maintained at 68° F. The sul 76 isobutane which is recycled, Jan alkyl halide
f
/
,
asiento
8
about 0.5 and 5 per cent by weight of aluminum
sulfate as the catalyst. maintaining said intimate
stream containing unreacted isopropyl chloride
which is also recycled, and ,a hydrocarbon frac
admixture at a reaction temperature not greater
tion boilingwithin the motor-fuel range and con
than about 125° F. for aperiod of time sumcient
taining a high concentration of highly branched
to effect reaction of alkyl halide with isoparañln
to form an isoparaiiin of high molecular weight
with elision of the corresponding hydrogen halide.
and subsequently removing from the reaction
isoheptanes, such as 2,2,3-trimethylbutane and
2,4-dimethylpentane, which have very good anti
knock ratings. In order to 'prevent an accumu
lation of undesirable constituents, a portion of
the butane stream and the alkyl halide stream
may be removed from the system, or these streams
may be subjected to further 'fractionation to pro
duce streams having higher concentrations of
products a hydrocarbon fraction containing iso
paraf?ns of high molecular weight so produced.
, 9. A process for the production of isoheptanesA
having a high antiknock rating, which comprises
establishing an intimate admixture of isobutane,
the desirable constituents. The isoheptanes with
isopropyl chloride, and sulfuric acid having a
high antiknock qualities are readily separated as
concentration greater than 95 per cent by weight
15
a, hydrocarbon fraction having a narrow boiling
and containing between about 0.5 and 5 per cent
range and containing them in high concentration.
by Weight of aluminum sulfate as the catalyst, '
In view of many possible modifications of the
maintaining said intimate admixture at a reac
process that Will be obvious to those skilled in the
tion temperature not greater than about 125° F.
art, the invention should not be limited unduly
by the foregoing specification and examples, but 20 for a period of time suillcient to effect reaction of
isopropyl chloride with isobutane to form lsohep
it_ should be understood to be as extensive in scope
tanes with eli'sion of hydrogen chloride, and sub
and equivalents as defined in the appended
sequently removing from the reaction products
claims.
I claim:
a hydrocarbon fraction containing isoheptanes so
A
_
1. In a process for the production of paraffin 25
hydrocarbons of relatively high molecular weight
from parañin hydrocarbons of lower molecular
weight, the steps which comprise establishing
produced.
-
'
'
10. A process for the production of isoparafiln
hydrocarbons of relatively high molecular weight
from isoparafiln hydrocarbons -of relatively low
molecular weight, which comprises establishing
an intimate admixture of an isoparaiiin in liq
uid phase, an alkyl halide in the liquid phase, 30 an intimate admlxture of an isoparaflin having
not more than eight carbon atoms per molecule,
selected from the group consisting of secondary
an> alkyl halide selected from the group con
and tertiary alkyl halides and having not more
sisting of secondary and tertiary alkyl'halides
than six carbon atoms per molecule, and sul
and having not more than six carbon atoms per
furic acid having a strength greater than 90
per cent by weight and containing between about 35 molecule and sulfuric acid having a concentration
greater than 95 per cent by weight and contain
0.5 and 5 per cent by weight of aluminum sulfate
ing between about 0.5 and 5 per cent by weight
as the catalyst, maintaining said intimate mix
of aluminum sulfate as the catalyst, maintaining
ture at a suitable reaction temperature for a
said intimate admixture ata temperature not
period of time sufiicient to effect a reaction of
isoparafiin >and alkyl halide to form isoparaiîlns of 40 greater than about 125° F. for a period of time
sufficient to effect an alkylation reaction between
high molecular Weight,- and subsequently sep
alkyl halide and isoparaifln to form isoparafilns
arating from the reaction mixture a hydrocar
of higher molecular weight, subjecting the reac
bon fraction containing isoparafiins of high mo
tion eiliuent which comprises unreacted reactants,
lecular weight so formed.
2. 'I'he process of claim 1 in which the alkyl 45 sulfuric acid and reaction products to a separat
ing means to separate sulfuric acid and hydrogen
halide is a tertiary alkyl halide.
3. The process of claim l in which the alkyl
halide is an alkyl chloride.
4. The process of claim 1 in which the .alkyl
halide is an alkyl fluoride.
halide, passing at least a portion of said sul
furic acid to admixture with the incoming charge
stock to the reactor, subjecting the remaining
50 predominantly hydrocarbon portion of the reac
5. The process of claim 1 in- which the alkyl
halide ls a secondary alkyl chloride and in which
tion effluent to a treatment with alkali to remove
acidic material, -passing alkali treated hydrocar
bon reaction effluent to fractionating means to
separate said eiliuent into a fraction containing
105 per cent by weight.
_
6. The process of claim 1 in which the sulfuric 65 isoparaflins in the motor fuel range and a light
acid has a strength between 96 and 102 per cent " hydrocarbon fraction, recycling a portion of said
the strength of sulfuric acid is between 100 and
by weight.
7. The process of claim l in which the sulfuric
acid has admixed with it a portion of spent acid
previously used in the process.
'
8. A process for the production of paramn hy
drocarbons of relatively high molecular weightv
light hydrocarbon fraction to said alkylation re
action, and subsequently removing the fraction
containing motor-fuel range isoparaflins of high
60 er molecular weight from the process.
l1. In a process of alkylating paramns to form
lother paratllns of higher molecular weight, the
step which comprises inter-reacting an alkylata
ble parafiin hydrocarbon and an alkyl halide in
from parailln hydrocarbons of lower molecular
weight, which comprises establishing an intimate
admixture of an isoparailin having not more than 65 the presence of concentrated sulfuric acid con
taining between about 0.5 and 5 per cent by
eight carbon atoms per molecule, an alkyl halide
weight of aluminum sulfate as the alkylating
selected from the group consisting of secondary
catalyst to form a paraiiin hydrocarbon of higher
and tertiary alkyl halides and having not more
molecular weight.
than six carbon atoms per molecule, and sul
FREDERICK E. FREY.
furic acid having a concentration greater than 70
95 per cent by weight and containing between
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