Note: Descriptions are shown in the official language in which they were submitted.
` 11003~4
This invention relates to a mineral oil-derived electrical
insulating oll having improved pour point.
Electrical insulating oils of mineral oil origin have
heretofore generally been produced from a naphthenic base
crude oil as the starting oil. It has recently been expected
to produce from a mixed or paraffinic base crude oil which
is available at a relatively low cost in large quantities.
However, electrical insulating oils of mixed or paraffinic
crude oil origin are disadvantageous in that they have a
high pour point.
This invention is applicable to the improvement of all
mineral oil-derived electrical insulating oils in pour point
and is particularly valuable in improving in pour point
electrical insulating oils produced from the mixed or paraffinic
base crude oil as the starting oil.
The electrical insulating oil composition o~ this invention
consists essentially of (I) 50 - 95 parts by weight of a
mineral oil-derived electrical insulating oil, (II) 5 - 50
parts by weight of a member selected from the group consisting
of (1) at least one arylalkane, (2) at least one diarylalkane,
(3) polybutene~ (4) a highly aromatic oil having a refractive
index of ( n d5) 1.56-1.60 obtained by hydrofining a distillate
contained in a fraction having a boiling range of about 250 -
about 400C at atmospheric pressure obtained by the pyrolysis
f petroleum at a temperature of about 6000 - about 9000C (5)
an oil obtained by hydrofining a distillate contained in a
fraction having a boiling range of about 230 - about 450C
at atmospheric pressure produced as a by-product by reforming
a hydrocarbon oil in the presence of a noble metal catalyst
0 and (6) an electrical insulating oil produced from a naphthenic
- 2 - ~
- 1~0~3g34
base crude oil as the starting oil, the insulating oil (6)
being not used as the oil (II) if the mineral oil-derived
electrical insulating oil (I) is of naphthenic origin and
(III) 0.001 - 1.0% by weight of a hydrocarbon-derived pour
point depressant, based on the total weight of the oils (I)
and (II), the depressant being at least one compound selected
from (i) a copolymer of ethylene and an ~-olefin having the
general formula CH2=CH-R wherein R is an alkyl group having
at least one carbon atom, (2) a poly-~-olefin, (3) a hydro-
generated, styrene-butadiene copolymer, (4) a condensed alkyl-
naphthalene, and (5) an alkylated polystyrene. Thus, this
invention is based on the finding or discovery that the addi-
tion of both the oil (II) and oil (III) to the oil (I) exhibits
such an unexpectedly great pour point-depressing action on the
oil (I) as may not be expected from the addition of the oil (II)
alone or the oil (III) alone to the oil (I).
This invention will be detailed hereinbelow.
The mineral oil-derived electrical insulating oil (I)
may be one which is produced from any of naphthenic, mixed and
paraffinic base crude oils, or may be blends of the oils so
produced.
The naphthenic base crude oil used herein is one con-
taining naphthenic hydrocarbons in large proportions and more
particularly the crude oil is such that its first key fraction
(kerosene fraction) has an API specific gravity of not greater
than 33 and its second key fraction (lubricating oil fraction
boiling at 275 - 300C at a reduced pressure of 40 mm of mer-
cury) has an API specific gravity of not greater than 20. As
is described in "Sekiyu Binran (Handbook on Petroleum)" on page
19, 1972 edition published by Sekiyu Shunju Co., Ltd., Japan
typical of the naphthenic base crude oils are a California
crude oil, a Texas crude oil, a Mexico crude oil, a Venezuela
crude oil and a Duri crude oil.
B - 3 _
`10~3~4
The paraffinic crude oil used herein is one contain-
ing paraffinic hydrocarbons in large proportions and more par-
ticularly the crude oil is such that its first key fraction
has an API specific gravity of not smaller than 40 and its
second key fraction ha~ an API specific gravity of not smaller
than 30 as is described in said ~andbook on Petroleum: typical
of the paraffinic base crude oils are a Pennsylvania crude oil,
a Minas crude oil and the like.
The mixed base crude oil used herein is one which is
qualitatively intermediate between the paraffinic and naphthenic
base crude oils and more particularly the mixed base crude oil
is such that its first key fraction has an API specific gravity
of 33 - 40 and its second key fraction an API specific gravity
of 20 - 30, typical of the mixed base crude oils are a Mid-
continent crude, oil, an Arabia crude oil, a Khafji crude oil
and the like.
This invention is applicable to an electrical insulat-
ing oil, as a base oil, of naphthenic, mixed or paraffinic
origin, as previously mentioned.
There have heretofore known many processes for the
preparation of electrical insulating oils from naphthenic base
crude oils, the processes including a process compri ing hydro-
fining a mineral oil to effect a 65 - 96% desulfurization and
then treating the thus-desulfurize~ mineral oil with a solid
absorbent (Japanese Patent Gazette No. 18584/61) and a process
comprising blending a mineral oil raffinate in hydrogenated form
having an aromatic content of not higher than 23% by weight with
not more than 15% by weight of a lubricating oil having a higher
aromatic content than the hydrogenated raffinate (Japanese Patent
Gazette No. 3589/66).
Processes for the preparation of electrical insulat-
ing oils from paraffinic base crude oils include, for example,
B - 4 -
10~4
~ pr~cess comprising disti31ing a distillate obtained by dewax-
ing a vacuum distilled gas oil fraction 5 - 95% of which boils
at 288 - 399C (550 - 750F) and recovering a heart cut there-
by obtaining an electrical insulating oil (Japanese Patent
Gazette No. 46123/74).
The present inventors have already filed a patent
application for a process for the preparation of an electrical
insulating oil which comprises refining with furfural or other
suitable solvents at 50 - 100C a distillate having a boiling
range of 250 - 400C at atmospheric pressure obtained by the
distillation of a paraffinic or mixed base crude oil at atmos-
pheric pressure or by the distillation at a reduced pressure of
a bottom oil obtained by the distillation of the crude oil at
atmospheric pressure, to effect a 30 - 75 wt.% desulfurization
thereby obtaining a raffinate, hydrofining the thus obtained
oil to remove therefrom 40 - 90 wt.% of the sulfur contained
therein, solvent d0waxing the desulfurized oil and, if desired,
successively treating the dewaxed desulfurized oil with clay
thereby to obtain the electrical insulating oi1 having a sul-
fur content of 0.1 - 0.35 wt.%, satisfactory oxidation stabil-
ity, electrical properties and resistance to copper corrosion
(U. S. Patent No. 4,008,148), and they have also already filed
a patent application for a process for the preparation of an
electrical insulating oil having a total sulfur content of
not more than 0.35 wt.%, excellent oxidation stability, thermal
stability, corona resistance and corrosion resistance which
consists essentially of (I) 80 - 99 parts by weight of a re-
fined oil obtained by solvent refining a distillate contained
in a fraction having a boiling range of 230 - 430C at
atmospheric pressure, the fraction being obtained by the dis-
tillation of a paraffinic or mixed base crude oil at atmospheric
_ 5 _
B
- ` 110~ 4
pressure or by the distillation at a reduced pressure of a
bottom oil obtained by the distillation of the crude oil at
atmospheric pressure, to produce a raffinate, hydrofining
the raffinate so produced, solvent dewaxing the thus-hydro-
fined oil and, if desired, treating the dewaxed hydrofined oil
with a solid adsorbent thereby to obtain the refined oil hav-
ing a sulfur content of no higher than 0.25 wt.% and an aro-
matic content of from more than 25 wt.% to 35 wt.% and (II)
1 - 20 parts by weight of a refined oil obtained by treating
the lubricating fraction of a mineral oil with a solid adsor-
ben~ (Japanese Pat. Appln. Laying-Open Gazette No. 93400/76).
There have been known various processes for the prep-
aration of electrical insulating oils from any one of crude
oils. Typical of them is a process for preparing an electrical
insulating oil by either providing a lubricating oil fraction
obtained by distilling at a reduced pressure a bottom oil
obtained by the distillation of the crude oil at atmospheric
pressure or providing a fraction having a boiling range of
about 260 - 400C at atmospheric pressure obtained by deasph-
alting the bottom oil to obtain a heavy oil, subjecting thethus-obtained heavy oil to hydrogenolysis at a temperature of
not lower than 350C and a high hydrogen pressure of not lower
than 150 kg/cm2G and distilling the thus-hydrogenolysed oil
to obtain a fraction having a boiling range within the range
of about 260 - 400C at atmospheric pressure, and, if necess-
ary, successively dewaxing the ~raction with a suitable solvent
thereby to prepare the electrical insulating oil. The sol-
vent may be a benzene-toluene-methyl ethyl ketone Ivol. ratio,
e.g. 25 : 25 : 50) mixture.
C1 3~4
This invention may of course be applicable not only
to electrical insulating oils obtained by the said typical
procesQ but also those of mineral oil origin obtained by any
other processes, irrespective of the manner of the processes.
The second component oil (II) of the electrical in-
sulating oil composition is at least one member selected from
the group consisting of (1) at least one arylalkane. (2) at
least one diarylalkane, (3) polybutene, (4~ a highly aromatic
oil having a refractive index of (nl5) 1.56 - 1.60 obtained
by thermocracking petroleum at about 600 - 900C to obtain
a fraction having a boiling range within the range of about
250 - 400C at atmospheric pressure and hydrofining the
fraction having a boiling range within the range of about
230 - 450C at atmospheric pressure, the fraction being
obtained at the time of réforming a hydrocarbon oil in the
presence of a noble metal catalyst and (6) an electrical in-
sulating oil obtained from a naphthenic base crude oil as
: the starting oil with the proviso that this in~ulating oil is
omitted if the mineral oil-derived electrical insulating oil
(I) is of naphthenic origin.
The axylalkane (1) used herein is an alkylbenzene
represented by the following general formula
~ R2
wherein Rl and R2 are each hydrogen or a hydrocarbon residue
having 1 - 20 carbon atoms with the proviso that the total
- 7 -
-` 110~3~4
of the carbon atoms of Rl and R2 is not less than 9, prefer-
ably 12 - 28.
The use of an arylalkane of said formula wherein the
total of the carbon atoms of Rl and R2 is less than 9 will
result in the production of an electrical insulating oil
having an unsatisfactory flash point and exhibiting an
unsatisfactory evaporation test result. The hydrocarbon
residues Rl and R2 may be straight-chained or else branch-
chained. The alkylbenzenes used herein may contain tetralin,
indene, indane and their hydrocarbon derivatives in amounts of
not more than about 50% by weight of the alkylbenzenes.
These alkylbenzenes may usually be obtained by conden-
sing (alkylating) benzene with an olefin or with a halogenated
paraffin in the presence of an acid catalyst such as a
Friedel-Crafts type catalyst. The alkylbenzenes which may
preferably be used in the industrial field, include mono-
alkylbenzenes having about 9 - 16 carbon atoms obtained at
the time of synthesis of straight-chained or branch-chained
alkylbenzenes for use as cleansers or heavy alkylbenzenes
obtained as a by-product at the time of synthesis of such
monoalkylbenzenes, and a bottom oil (obtained after the
distilling-off of the alkylbenzenes for use as cleansers).
It is preferable that these alkylbenzenes be used after their
treatment with an adsorbent. Generally, it is also preferable
that the arylalkanes be hydrofined prior to their use in
view of the electrical properties of electrical insulating
oil compositions to which the arylalkanes are to be added.
As catalysts for said hydrofining, there may preferably
be used at least one member selected from the group consisting
of metals of Groups VI, VII and VIII of the Periodic Table,
` llOQ3~4
and the oxides and sulfides of the metals ; the catalysts
may preferably be supported on a solid carrier such as
sillca, alumlna, diatomaceous earth or activated carbon.
More particularly, the catalysts which may be or may not
be supported on the aforesaid carrier include palladium,
platinum, nickel, copper-chromium, cobalt-molybdenum, nickel-
molybdenum and nickel-tungsten. The hydrofining may be
carried out at a pressure of usually 2 - 50 kg/cm2G and a
temperature of 50 - 400C and at a liquid hourly space
velocity (LHSV) of l - 15 vol./vol.
If the arylalkanes according to this invention are to
be produced from straight-chained heavy alkylbenzenes, then
it is particularly preferable that the heavy alkylbenzenes
should be hydrofined under such conditions that only the
alkyl polycyclic aromatic compounds contained as impurities
in the heavy alkylbenzenes are select1vely hydrofined and
should thus be used as a compound having an absorbancy of
not higher than 0.4 x 10 3 g/l.cm at a wavelength of 400 m~
in the wavelength region of visible rays.
The diarylalkane (2) according to this invention is
a compound represented by the following general formula
R5
R ~ ¦ ~ R4
~6
wherein Rl , R2 ~ R3 and R4 are each hydrogen or an alkyl
group having 1 - 15 carbon atoms with the proviso that the
total of the carbon atoms of Rl - R4 is at least 2, and R5 and R6
_ g _
110~3Q4
are hydrogen or a methyl group. The diarylalkanes may be
produced easily at a low cost from aromatic compounds obtainable
in the petrochemical industry, by the use of any one of
various known processes. These knownprocesses include a
process comprising reacting styrene, ~ -methylstyrene or
their alkyl derivative with benzene or an alkylbenzene in the
presence of an acid catalyst such as sulfuric acid or a cationic
ion exchange re~in and a process comprising dehydrochlorination
condensing an aryl chloride with benzene or an alkylbenzene
in the presence o~ a Friedel-Crafts type catalyst.
Diarylalkanes produced by the use of other known processes
may also be used in the practice of this invention. In
addition, there may further be used diarylalkanes containing
not more than 10,~ of a by-product produced at the time of
reaction for producing the diarylalkanes. Typical of the
diarylalkanes are ~ -methylbenzyltoluene, d, d' -dimethyl-
benæyltoluene, ~-methylbenzylxylene, d, ~'-dimethylbenzylxylene
and mixtures thereof.
The polybutene (3) used herein is a liquid polymer
consisting mainly of isobutylene and is obtained by polymerizing
a butane-butene fraction, obtained as a by-product when
naphtha, for example, is thermocracked in attempts to produce
ethylene, propylene or the like, at a temperature of about
-30 to 30C in the presence of a Friedel-Crafts type catalyst
such as aluminum chloride. The polybutene used herein
should have an average molecular weight of about 200 - 400,
prefcrably about 250 - 300.
The petroleum (4) according to this invention is thermocracked
at about 600 - 900C to obtain a fraction boiling at about
250 - 400C at atmospheric pressure, a part or the whole
-- 10 --
' llOQ3~}4
of which fraction is hydrofined thereby to obtain a highly
aromatic oil having a refractive index of (nd5) 1.56 - 1.60.
The highly aromatic oil will be further detailed hereinbelow.
Hydrocarbons having at least 5 carbon atoms are
obtained as a by-product when naphtha, kerosene, gas oil or
other petroleum is subjected to steam cracking, thermo-
cracking, catalytic cracking or the like at approximately
600 - 900C to produce therefrom ethylene, propylene and
other lower olefins. Among these olefins, the olefins having
5 and 9 carbon atoms are partly used as a starting material
for petroleum resins, those having 6 - 8 carbon atoms are
used as a starting material for producing benzene, toluene
and xylene and those having at least 9 carbon atoms excspt
for those having 9 carbon atoms for the petroleum resins
are used in the practice of this invention.
The residual cracked oil obtained by the aforesaid
naphtha cracking is very highly aromatic substantially with-
out paraffinic and naphthenic oils being contained. The
residual cracked oil is distilled at a reduced pressure to
separate therefrom a fraction having a boiling range within
the range of about 250 - 400C. Or the cracked oil is dis-
tilled at a reduced pressure to separate it into a liquid
material boiling at not higher than about 400C and a heavy
material boiling at not lower than this temperature. Then,
said liquid material is heat treated at not higher than about
200C at atmospheric or superatmospheric pressure for longer
than about one hour or else it is catalytically heat treated
in the presence of a Friedel-Crafts type catalyst to polymer-
ize alkylindenes and other unsaturated compounds contained
therein thereby converting it to a heavy material which is then
X
110~304
dlstilled to remove therefrom a polymerized material having
a boiling range of higher than 400C while recovering a
dlstlllate having a bolling range within the range of about
250 - 400C. The boiling range of the distillate used
herein may include preferably at least about 80%, more
preferably at least 90% of said range of about 250 - 400C.
The distillate so recovered is then hydrofined to obtain a
desired highly aromatic hydrocarbon having a refractive
index of ( n2d0 ) 1.56 - 1.60 and a specific dispersion of
not lower than 200, preferably 225 - 300. The catalysts
u~ed for said hydrofining may be conventional ~no~m ones
such as, preferably, nickel, molybdcnum and cobalt oxides and
sulfides supported on an alumina-containing carrier ; the
most preferable ca-talyst is preliminarily sulfurized
nickel oxide-molybdenum oxide supported on an alumina carrier.
In the hydrofining, the pressure used is usually in the range
of 20 - 100 kg/cm2~, preferably 25 - 60 kg/cm2G ; the reaction
temperature used is in the range of 2~0 - 400C, preferably
260 - 340C ; and the amount of hydrogen fed is in the range
'0 of 100 - 10,000 Nm3, preferably 200 - 1,000 Nm3.
The hydrofined oil (5) according to this invention
obtained by hydrofining a distillate contained in a fraction
having a boiling range of about 230 - 450C at atmospheric
pressure produced as a by-product at the time of reforming
a hydrocarbon oil in the presence of a noble metal catalyst,
will be detailed hereunder. A hydrocarbon oil, such as
straight-ru~l naphtha or craoked gasoline, having a boiling
range of about 40 - 200C, preferably about 60 - 180C ,
is reformed in the prescnce of a noble metal catalyst to
) produce a high octane number gasoline, benzene, toluene,
- 12 -
110~3~4
xylene and other aromatic hydrocarbons simultaneously with
the production, as a by-product, of a fraction having a
boiling range of about 230 - 450C at atmospheric pressure
in which is contained a heavy oil distillate usable as
material for the hydrofined oil (5) in the practice of this
invention. The boiling range of the hydrofined oil (5) may
include preferably at least ~30%, more preferably at least
90%, of that of the said fraction boiling at about 230 -
4509C. The heavy oil distillate is usable as the hydrofined
oil (5) without need of distillation thereof if it meets the
requirements for the oil (5), however, it may be preferable
to obtain such a usable distillate meeting the said require-
ments by distillation of the original heavy oil distillate.
Almost all of the usable heavy oil distillate consists of
polycyclic aromatic hydrocarbons having at least 10 carbon
atoms. The noble metal catalysts used herein may be those
which are known to be usable for such a reaction as above.
Particularly preferable catalysts include metals of the
Platinum Group of the Periodic Table and mixtures thereof,
each supported on a solid carrier. There may also prefer-
ably be used catalysts comprising the Platinum Group metal
and mixtures thereof in combination with at least one member
selected from Ge, Sn, Re, Fe, Pb and halogens, the catalysts
being supported on a solid carrier. The solid carriers which
may preferably be used include alumina, silica, zeolite and
silica-alumina~ The reforming reaction according to this
invention may be carried out at a reaction pressure of
1 - 50 kg/cm2G, preferably 5 - 40 kg/cm G and a reaction
temperature of 400 - 600C, preferably 470 - 530C, at a
hydrogen feed rate of 100 - 1,500 Nm3, preferably
300 - 1,000 Nm , per Kl of oil and at a LHSV of
- 13 -
--` 110~3~4
0.5 - 5 hr 1, preferably 1 - 3 hr 1 The aforesaid heavy oil
distillate is usually subjected to hydrofining treatment
thereby obtaining a desired hydrofined oil (5). The hydrofining
catalysts used herein include the oxides, sulfides and
mixtures thereof of metals of the Groups IB, IV and VIII
of the Periodic Table, the catalysts being supported on an
inorganic carrier such as bauxite, activated carbon, diatomaceous
earth, zeolite, silica, alumina or silica-alumina. The
preferable metal~ of the Groups IB, IV and VIII include
cobalt, nickel, molybdenum and tungsten. Particularly preferable
catalysts are those comprising a mixture of at least two of
molybdenum oxide, tungsten oxide and cobalt oxide, the mixture
being supported on an alumina carrier. In the hydrofining
treatment, the reaction temperature used is 230 - 400C,
preferably 260 - ~60C ; the reaction pressure used is usually
20 - 150 kg/cm2G, preferably 25 - 80 kg/cm2G ; the hydrogen
feed ra-te used i5 100 - 10,000 Nm3, preferably 200 - 1,000 Nm3,
per kl of heavy oil distillate ; and LHSV used is 0.5 - 5 hr 1,
preferably 1 - 4 hr 1
~0 The hydrocarbon-derived pour point depressant which
is the component (III) according to this invention, is
~' ~o~7o/~e~
at least one compound selected from (1) a coplymor of ethylene
and an ~-olefin having the general formula CH2=CH-R wherein R i~
an alkyl group having at least one carbon atom , (2) poly- d-olefin
~5 ( ~-olefin polymer), (3) a hydrogenated, styrene-butadiene
~o~o/"~e ~^
copl~mor, (4) a condensed alkylnaphthalene and (5) an alkylated
polystyrenc.
The copolymers (1) of ethylene and ~-olefin include
ethylene-propylene copolymers, ethylene butene-l copolymers
~0 and ethylene hexene-l copolymers with ethylene-propylene
- 14 -
-- 110~1t334
copolymers being particularly preferred. The ethylene~ a-
olefin copolymers used herein are essentially amorphous
oil-soluble ones having a number average molecular weight
of usually 10,000 - 200,000, preferably 20,000 - 70,000,
and an ethylene content of 30 - 90 mol%, preferably 40 - 80
mol%. The term "essentially amorphous" used herein means that
the ethylene~ -olefin copolymers may have some degree of
crystallization therein, the degree being usually 0 - 5%,
preferably 0 - 2%. In addition, it is preferable that the
copolymers have a relatively narrow distribution of molecular
weight, the distribution being usually not higher than 8,
particularly not higher than 4. The ethylene~ a-olefin
copolymers may be produced by known processes. The co-
polymerization may be effected by reacting ethylene with at
least one a-olefin in an inert organic solvent containing an
organic solvent-soluble specified homogeneous Ziegler type
catalyst at atmospheric or somewhat superatmospheric pressure
and at a temperature varying from a somewhat low temperature
to a somewhat high temperature. The Ziegler type catalyst
which may preferably be used is a coordination catalyst com-
prising a vanadium compound and organoaluminum compound such
as VOC13 - Al (C2H5) system.
The poly-a-olefin or polymer of a-olefin t2) usable
as the component (III) of this invention is a homopolymer or
copolymer of ~-olefin having the general formula CH2=CH - R
wherein R is any one of alkyl groups which have 7 - 18,
preferably 8 - 16, carbon atoms and are identical with, or
different from, each other at the same time. The polymer
of a-olefin (2) may also be a mixture of said homopolymer
and copoly~er.
-` 110~3~4
The polymer or copolymer contains ~ CH2 ~n in which n is at
least 6. These polymers of a-olefin may be produced in the
presence of the same homogeneous Ziegler type catalyst as
the aforesaid ethylene~ a-olefin copolymer (1). The polymer
of ~-olefin has a number average molecular weight of usually
10,000 - 200,000, preferably 20,000 - 70,000 and is essentially
amorphous, in addition, it should preferably have a relatively
narrow molecular weight distribution.
The hydrogenated styrene-butadiene copolymer (3)
usable as the component (III) according to this invention
may be produced by a known process such as a process com-
prising copolymerizing styrene and butadiene in the presence
of an alkyl-alkali metal compound, such as butyllithium, as
a catalyst and hydrogenating the resulting styrene-butadiene
copolymer using a known hydrogenating technique. It is
desirable that at least 90%, preferably 100%, of the double
bonds contained in the original styrene-butadiene copolymer
be hydrogenated.
The hydrogenated styrene-butadiene copolymer (3) is
preferably a random copolymer and has an average molecular
weight of usually 10,000 - 200,000, preferably 20,000 -
70,000. The ratio of content between the styrene units and
the butadiene units in the copolymer is 15 - 50 : 85 - 50,
preferably 25 - 40 : 75 - 60.
The condensed alkylnaphthalene (4) usable as the
component (III) is a condensate of dichloroparaffin and naph-
thalene and may be synthesized by a known process using a
catalyst such as anhydrous AlC13. The dichloroparaffin usable
herein is dichloride of a paraffin having about 15 - 60 car-
bon atoms. The condensed alkylnaphthalene usable herein
- 16 -
~,.
11~103~4
has a molecular weight of several thousands to hundred thousands,
usually about 2,000 - 70,000.
The alkylated polystyrene (5) usable as the component
(III) according to this invention may be produced by a
konwn process such as a process comprising subjecting styrene
to radical polymerization in the presence of a peroxide,
such as benzoyl peroxide, as an initiator. Starting
polystyrene for the alkylated polystyrene (5) has a number
avera~e rnolecular weight of 10,000 - 150,000 , preferably
20,000 - 70,000. The starting polystyrene is alkylated
by contacting an alkyl halide therewith in the presence of
a Friedel-Crafts type catalyst. The alkyl halide is represented
by the general formula ~X wherein R is an alkyl group having
6 - 20, preferably 8 - 18, carbon atoms and X i5 a halogen
atom.
This invention is based on the finding or discovery
that a mineral oil-derivçd electrical insulating oil (I)
may remarkably be depressed in pour point without impairing
the electrical properties thereof by adding thereto a specified
oil (II) and a specified hydrocarbon-derived pour point
depressant each in a specified proportion.
According to this invention, the blending ratio by
weight of the mineral oil-derived electrical insulating
oil (I) as the 1st component to the oil (II) as the 2nd
component may be in the range of 50 - 95 : 5 - 50, preferably
60 - 90 : 40 - 10, and more prefe~ably 70 - ~5 : 30 - 15.
The use of the oil (II) in a higher blending ratio than the
oil (I) will not be effective in further improving the oil (I)
in properties, particularly pour point, nor will it be
economical. The use of the components (II) and (I) in a
blending ratio of less than 5 : 95 will not be effective
- 17 -
~OQ3~4
in remarkably depressing the pour point of the component (I)
although such remarkable depression is characteristic of this
invention. In addition, the hydrocarbon-derived pour point
depressant (III) as the third component of the insulating
oil composition of this invention may be used in amounts of
0.001 - 1.0~, preferably 0.05 - 0.2Yo,Of the total weight of the
components (I) and (II).
Furthermore, the electrical insulating oil composition
of this invention may be incorporated with a known antioxidant
such as DBPC (di-tert.-butyl-p-cresol), N-phenyl-~ -naphthylamine,
nicotinic acid or hydroquinoline.
This invention will be illu6trated. by the following
non-limitative Ex~mple9 wherein all percentages and parts
are by weight unless otherwise specified.
Example 1
There was obtained a distillate having a boiling range
of 260 - 380C at atmospheric pressure and a sulfur content
of 2.2 wt.% by distilling an Arabia crude oil at atmospheric
- pressure to obtain a bottom oil and distilling the thus-obtained
bottom oil at a reduced pressure. The distillate so obtained
was extracted with furfural in a solvent ratio (furfural/
distillate) of 1.3 at an extracting temperature of 75 - 90C
to obtain a raffinate having a sulfur content of 0.8 wt.%.
The thus-obtained raffinate was hydrofined at 310C under a
hydrogen pressure of 40 kg/cm2G in the presence of an alumina-
carried NiO-MoO3 catalyst (NiO : 3.0 wt.%, MoO3 : 14.0 wt./~)
to obtain a hydrofined oil which was dewaxed with a benzene-
toluene-methyl ethyl ketone mixed solvent in a solvent ratio
(solvent/oil) of 1.6 at a cooling temperature of -30C and
successively treated with clay at 70C for one hour thereby
- 18 -
110~3Q4
obtaining an electrical insulating oil (A).
Separately, there was obtained heavy alkylbenzenes
having a boiling range of about 310 - 404C as a by-product
at the time of synthesis of branched alkylbenzenes for use
as cleansers from benzene and olefins composed ma~nly of
propylene tetramer in the presence of boron trifluoride as
a catalyst. The heavy alkylbenzenes so obtained was then
treated with clay at 70C for one hour to obtain a clay-treated
oil as the component (II) of the insulating oil composition
of this invention. Thirty (30) parts of the clay-treated oil
and 70 parts of the electrical insulating oil (A) were
blended together thereby to obtain a blended oil (B).
Furthermore, an essentially amorphous ethylene-propylene
copolymer having an average molecular weight of 36,000 and a
propylene content of 30 mol% was added to the blended oil (B)
in the amount of 0.05% of the oil (~) thereby obtaining an
electrical insulating oil (C 3 according to this in~ention.
The properties of the electrical insulating oil (A), blended
oil (B) and electrical insulating oil (C) are shown in Table 1.
For comparison, the said amorphous ethylene-propylene
copolymer was added to two equal portions of the electrical
insulating oil (A) in the amounts of 0.05,~ and 0.1% of the
portions of the oil (A) to obtain blended oi7s ~D) and (E),
respectively. The properties of these oils (D) and (E~ are
also indicated in Table 1.
For further comparison, the blended oil (B) was incorporated
with 0.2% of polymethacrylate which was a non-hydrocarbon
derived pour point depressant, thereby to obtain a blended
oil (F) the properties of which are also sno~m in Table 1.
As is apparent from Table 1, the addition of only the
-- 19 --
lll)Q3~4
clay-treated heavy alkylbenzenes to the electrical insulating
oil (A) was hardly effective in depressing the pour point
of the oil (A), the addition of only the amorphous ethylene-
propylene copolymer to the electrical insulating oil (A)
was somewhat effective in depressing the pour point of the
oil (A) and the electrical insulating oil (C) obtained by
the addition of both the clay-treated heavy alkylbenzenes
and the amorphous ethylene-propylene copolymer to the insulating
oil (A) exhibited a remarkably depressed pour point without
imparing the other properties required in electrical insulating
oils. Furthermore, an electrical insulating oil prepared
by adding polymethacrylate to the blended oil (B) exhlbited
remarkably unsatisfactory electrical properties, steam emulsion
number and like properties and was therefore unsatisfactory
as such.
In Table 1, corrosion test and evaluation of corrosiveness
were carried out in accordance with ASTM D-1275 and ASTM D-130,
respectively.
- 20 -
110~3~4
~o 8
a) ~ ~ ~
-- ~ ~ O ~ ~ O
~) ~1 U ~1 + ~ N + ~, d' [` O ~ O
m o ~ o P~ R PO~ o o <`J ~;
,
u~
-- .~ ~o
a~ liil ~ 1 ~ 3 _1 ~
-- ~ ,1 _ + ~1 >,_I 1-') X O
S: ~ U ~ oQI OQ~-I ~ "~ o ,Q d'
m o ~ o~3 ~,o ~ o
__.__ _
I ~ s, . U~
~^ C)~ 3 1~ -1O
. _~ a~
~-- ~) ~ _ ~ 1 Lt) t` X O
~m o ~-~ o ~ ~ ~ ~ ~ o ~ ~
~ _,
E~,1 ~ ~ ~ ~
o -,~ ~ n
r~ ~ .~ ~
s~ ~ c) ~ L~l o
_ ~ ~1 _ + ~ a) + _I ~ . ~ In
U ::1 o ~S ~ N ~ 0<~1 X O
1 ~ 0~ h 0 d' ~1 O ~ O d'
~ O ~~1 0 ~ O ~ O ~ ~
~1
~^ .~
a~ m s~ + ~ u~ o
-- ~_ ~a~ . ~ ~r
~: ~ ~ t` ~ oo R
o ~: ~ -- -lo
o R
. ~ ~q~ ~ ~ o
C~ ~ O - ~ o O
o ~q ~ V ~_ .,
~ '~ V Vo ~ ~ ~ V 1` ~ ~ ~ O
~:: a~ . ~1 a) o ~ ~ 1 o
,~ ~,3 S~ >~1 ~ ~
o ~ ~ ~ ~1 x ~ ~ a) v
v ~ ~v ~ 1 ~
v ~ ~ ~ O ~ R ~ ~ ~ ~
. o o o ~ c o ~1 a) ~ H ::~ 0
n _ _ u) c ~ X
~ 21 ~
` 110~3~4
ExamPle 2
The blended oil (B) obtained in Example 1 was
incorporated with 0.1% of a styrene-butadiene copolymer
having a number average molecular weight of about 40,000 and
a styrene content of 32 mol%, in which copolymer 95~ of the
doubles bonds of the butadiene has been hydrogenated, thereby
to obtain an electrical insulating oil (G). In addition, the
electrical insulating oil (A) obtained in Example 1 was
incorporated with 0.1~ of said hydrogenated styrene-
butadiene copolymer to obtain a blended oil (H). The propertiesof the oils (G) and (H) are shown in Table 2.
>o
- 22 -
110~3Q4
U D ~ 11 0 1~
0~ _
O S~
~ ~:: ~ ~1 ~ ~
c~ 0 a~ ~ ~ ~3E~
O S~ h :~ ~ CD ~ h
h ~ U O O
-- 23 --
'~
3 1(~Q3~i4
Example 3
Seventy-five (75) parts of the electrical insulating
oil (A) were blended with 25 parts of polybutene having an
average molecular ~reight of about 280 to obtain a blended
oil (J). The blended oil so obtained was then incorporated
with 0.07~ of of the a~orphous ethylene -propylene copolymer
as used in Example 7 to obtain an electrical insulating oil (K)
having the properties sho~m in Table 3. For comparison,
Table 3 shows the properties of a blended oil (L) prepared
by incorporating the electrical insulating oil (A) with
0.07% of the ethylene-propylene copolymer.
~0
- 24 -
110~3~4
n
,~"
l o ~
0~ Cc ~o o
x o
o _~
~0 ~
~ I',
_ 0 ~o ~
o ~ ~ U~ X o I ~ I 1~
,~0 oo '~` o~ o ~ ~ ~
~ ,
o ~ o^ ~_ ~OEo
O 0 E u o --~ x 0 ~ ~ , o
:~ ~ O ~ o a) ~ H ~ ~ ~a -
o ~ ._~ ~ ~ s~ æ ~
11003~4
Example 4
A distillate having a boiling range of about 280-
380C obtained by distilling a Duri crude oil at atmospheric
pressure, wa~ hydrofined at a reaction temperature of 330C,
a hydrogen pressure of 35 kg/cm2G and a LHSV of 2.0 in the
presence of the same alumina-carried NiO-MoO3 catalyst as
used ~n Example 1 thereby to obtain a hydrofined distillate
which was treated with clay at 70C for one hour to yield
an electrical insulating oil (M). Seventy (70) parts of the
insulating oil (M) were blended with 30 parts of the clay-
treated heavy al~ylbenzenes as used in Example 1 to obtain
a blended oil (N) which was then incorporated with 0.01%
of the ethylene-propylene copolymer as u~ed in Example 1
thereby obtaining an electrical insulating oil (0) according
to this invention. The properties of these oils are shown
in Table 4. For comparison, the base oil (M) was incorporated
with 0.01% of the ethylene-propylene copolymer to obtain a
blended oil (P) having the properties shown in Table 4.
- 26
3~4
_ W
_ `_ W
P. ,, ~ U~
_ .,, Q,
~ o ~o ,,
.,1 -! ~ ~ o
o ~ o X o
.
.,,~ ~ ~ , , o .
~ ~ ~ ~1~ ~ .
~ ~ o~ .
m ~ 3 u
~A _ ,a W
U)
~rl ~ O
O O ~ ~I) O U~
w ~ h ~ X O
115 ~ + d N + I ~ ~
u ~ ~ a) o I u~ O
,~ ~ ~1 ~ h a~i
h tlS h td ~) ,4a) ~ ~1
~_I ~,1 1 ~ ~
U ~ W ~ ~
~ ~ _1 ~ ~ ~ O
~-~ ,~ u
_ ~
o~ a~ o
~ ~ ~ ~ u~
,, ~ ~~ al . O
W O tl~1 N t` X O t`~
_I ~rl + aJ ~
R ~5 ,1~S~ O I 0 O
~ w S--I ~a ~
E~ ~ ~ ~I ,1
m ~
_ .,., c~ _
o ~o
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s~ ~ ~ .
1 0 o
o ~ .
Q) ~
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.~ ~ ~
.,, ~ ~
o o
O ~ ' ~ ~
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~,~ oa3 o aJ ~J H
OO O ~rl 0 1
~ ~ 0 a aD cq 0~
- 27 -
~ .
