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Патент USA US2409060

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Patented Oct. 8, 1946
James V. Montgomery, Brownwood, Tex, L. Bar
rett Goodson, New York, N. Y., and Robert W.
Henry, Bartlesville, Okla., assignors to Phillips
Petroleum Company, a corporation of Delaware
No Drawing. Original application August 23,
1940, Serial No. 353,956. Divided and this ap
plication June 9, 1944, Serial No. 539,590
2 Claims. (Cl. 196—13)
’ dewaxing solvent in which oil and wax are miscible
This invention relates to solvent dewaxing and
solvent extraction of mineral oils and is more par
ticularly concerned with an improved dewaxing
and extraction solvent for use in mineral oil
at normal atmospheric temperatures and in which
the oily constituents are miscible at dewaxing'
Another object is to provide a dewaxing solvent
in which the wax constituents are relatively in
This application is a division of Serial No.
353 956, ?led by us August 23, 1940.
The utility of the unsaturated heterocyclic
nitrogen bases in the solvent dewaxing and sol
soluble at dewaxing temperatures-
372,208 (1921), and by the French Patent 598,502
which fraction of commercial pyridine is com
posed substantially of picolines) are completely
Still another object of this invention is to pro
vide a solvent which may be used advantageously
vent extraction of mineral oils has long been 10v with antisolvents for dewaxing and for extrac
known to the art. The use of pyridine for extract—
Still other objects and advantages will be appar
ing hydrocarbon oils from coal and other bitu
ent from a study of the disclosure which follows.
minous materials was disclosed by Baker, Trans.
We have discovered that the saturated or par—
Am. Inst. Min. Engrs, 20, 159 (1900-1901); by
Donath, Zeit. Fiir Angewandte Chemie 19, 657-668 15 tially saturated heterocyclic nitrogen bases are
miscible with petroleum oils at much lower teme
(1906); by Bedson, J. Soc. Chem. Ind., 27, 147 to
peratures than are the corresponding unsaturated
150; Hofmann and Damm, Brennstoff Chemie,
compounds. For example, the pipecolines or satu
4, 65 to 73; and others. The use of pyridine in
rated picolines, (prepared by hydrogenating the
the solvent fractionation of hydrocarbon oils was
240 to 500° F. fraction of commercial pyridine.
disclosed by German Patents 319,656 (1918) and
(1924). Poole, in Ind. and Eng. Chem. p. 170 to
177 (1931), discussed the solubility of oil and
wax in various solvents, including pyridine.
Ferris, et al., Ind. and Eng. Chem. p. 753-761 25
miscible with a treated dewaxed Mid-Continent
residual lube stock of 90 S. U. V. at 210° F. and
85 V. I., at —35° F., while a mixture of a simi
(1931) , reported the investigation of a large num
larly selected cut of anhydrous picolines and this
ber of organic compounds, including pyridine,
quinoline and alpha picoline, These materials
investigated by Ferris evidently contained some
rated and partly saturated heterocyclic nitrogen
same Mid-Continent oil separated into two phases
upon cooling the mixture to +50 F. These satu
water since the temperatures for complete mis~ 30 bases have complete solubility for oil and wax
at elevated temperatures and show marked anti
cibility with 25° API gravity oil of 0.851 viscosity
gravity constant, were quite high, as 77° F. for
pyridine, 58° F. for quinoline, and 86° F. for alpha
solvent powers for wax at low temperatures,
with complete solubility for the oil component,
thus making them excellent solvents for use in the
picoline, whereas anhydrous pyridine and pico
solvent dewaxing of mineral oils to produce useful
oils of low pour point. The addition of hydro
gen to the unsaturated nitrogen compounds has
increased their miscibility with hydrocarbon oils
at low temperatures. These saturated and par
tially saturated bases include such compounds as
lines are miscible with such an oil at temperatures
slightly below 0° 1i‘. Numerous United States and
foreign patents have been issued covering the
use of unsaturated heterocyclic nitrogen com
pounds for the solvent extraction and solvent de
waxing of mineral oils. Careful examination,
piperidine, pyrroline, pyrrolidine, hydrogenated
pyridines, pyrazoline, pyrazolidine, etc., and their
however, reveals that in all cases these solvents
were restricted in their usefulness as dewaxing
alkyl derivatives, as the pipecolines, methyl
pyrrolidines, etc.
solvents by a relatively low solubility for the oil
component, as well as for the wax component, par
As an additional advantage, we have found
ticularly at the low temperatures suitable for de
waxing mineral oils to the low pour points re
quired for commercial utility. In all cases where
solvent dewaxing of high viscosity index oils to
low pour points (0° F. and below) was attempted,
that while the unsaturated bases such as picolines
are completely miscible with water the corre
sponding saturated compounds, the pipecolines,‘
are not miscible with water in all proportions.
For example, the addition of two volumes of water
to one volume of anhydrous pipecolines results in
it was necessary to use solubility enhancers to
hold the oil in solution. The use of these solu
bility enhancers resulted in a large di?erential
between the dewaxing temperature and the pour
point of the dewaxed oil since such materials in
themselves have an appreciable solubility for
wax even at the dewaxing temperatures.
One object of this invention is to provide a
group of new and improved selective solvents for
use in lubricating oil re?ning.
the formation of two phases of approximately
equal volume. This property makes the drying
of these solvents after use in dewaxing or solvent
extraction less di?icult.
pyridine and pyridine homologues and applicants
have found that their preferred solvent may be
prepared by hydrogenation of that fraction of
Another object of this invention is to provide a
Commercial pyridines are usually mixtures of
commercial pyridine, picoline, quinoline, etc., boil
ing between 240° and 500° F, This hydrogenated
(3) The solubility of commercial wax is very low
at temperatures of 50° to 70° F.
(4) The wax crystals are large and easily ?lter
(5) Acetone boils at a low temperature, 134° F.,
and it may be completely removed from
the oil.
product consists essentially of hydrogenated pico
lines, commonly called pipecolines, with some
other nitrogen base compounds in smaller propor
tions. The hydrogenation of this 240-500° F.
commercial pyridine fractions lowers the boil
ing range of‘ the fraction to approximately
215-450° F., since the boiling points of the hydro
Acetone, however, has a very low solvent power
genated pyridine, picolines, quinolines, etc., are
oil and for this reason, it is not practical to
ordinarily 10°*60° F. lower than the boiling points 10 attempt
to manufacture lubricating oils of low
of the unhydrogenated parent compounds, for
pour point, such as 0° F. or below, by the use of
acetone alone as a dewaxing solvent since the
oil-wax-solvent mixture separates into two liquid
Unsaturated heterocyclic
Corresponding hydrogenerated
phases at low temperatures. The oil phase is
nitrogen base, B. P.
Pyridine, 239° F.
Alpha picoline, 264° F.
Beta picoline, 290° F.
Gamma picoline, 289° F.
Quinolinc, 457° F.
nitrogen base, B. P.
Piperidine, 228° F.
3 methyl piperidine, ‘240° F.
3 methyl piperidiue, 259° F.
4 methyl piperidine, 264° F.
Deca~hydro quinoline, 400° F.
highly viscous and ?ltration of wax from this
phase is difficult. This disadvantage has been
overcome by blending supplementary solvents or
“solvent enhancers” with the acetone to hold the
oil in solution. Examples of materials suitable
for use as solubility enhancers are: Petroleum
naphthas, benzene, toluene, isopropyl ether, etc.
While satisfactory solvents for practicing our
Unfortunately, however, these materials have a
invention may be prepared by hydrogenation of
rather high solubility for wax as well as for oil
commercial pyridine fractions, as above disclosed,
at the dewaxing temperatures. When the solvent
suitable solvents may also be prepared by ?rst 25." is removed from the oil after the dewaxing opera~
hydrogenating the commercial pyridine followed
tion, this dissolved wax remains in the oil, re
by fractionation into suitable fractions. Frac
sulting in an oil of high pour point, or a large
tions of the hydrogenated pyridines should be cut
differential between dewaxing temperatures and
from approximately 215° to 450° F. This fraction
the pour point of the recovered oil. As examples
of hydrogenated products corresponds roughly to
of such blends, the following experiments are
the boiling range of 240° to 500° F. for the un_
hydrogenated selected pyridine fraction.
The following is an example of the fractiona
tion of a commercial pyridine into 10 per cent
fractions by volume:
10% out No.
(1) One volume of treated dewaxed Mid-Conti
nent lubricating oil stock of 90 S. U. V.,
at 210° F. and 85 V. I., was mixed with one
volume of a solvent composed of 40% ace
tone, 40% benzol and 20% toluol. A phase
separation occurred on chilling to +10° F.
(2) One volume of treated dewaxed Mid-Conti
nent lubricating oil stock of 90 S. U. V.,
at 210° F. and 85 V. I., was mixed with
one volume of a solvent composed of 30%
acetone, 50% benzol and 20% toluol. A
phase separation occurred at -15° F.
4:vi (3) One volume of treated waxy Mid-Continent
residual lubricating oil stock was mixed
with four volumes of a solvent composed
of 30% acetone, 50% benzene and 20%
Itmight be mentioned that some commercial
pyridines contain much higher boiling material
than the above given example.
We have found that when desired, the above
mentioned saturated and partially saturated het
erocyclic nitrogen containing compounds, as the
pipecolines, may beused with known wax anti
solvents, such as low boiling alcohols, acetone,
methyl ethyl ketone and/or other aliphatic or
toluol, chilled to 0° F. and ?ltered. The
recovered oil was of +15° F. pour point, 83
V. I., and 83 S. U. V. at 210° F.
Thus, the maximum proportion of acetone
which could be used in the solvent; for dewaxing
at 0° F. was about 30%, and under these condi
tions the solubility of the wax at 0° F. was suffi
ciently high as to give a +15° F. pour point on
the recovered oil. Furthermore, when benzene
alone is used as a diluent, it tends to crystallize
aromatic ketones, aniline, nitrobenzene, pyridine,
out of solution at low temperatures. When a third
picolines, pyrrol, etc., to give exceptionally low
60 component such as toluol is used to prevent the
pour point oils.
freezing out of the benzol the resulting three
It should be added that a blend of pipecoline
component mixture is dif?cult to maintain in the
with furfural or phenol would not be a satisfac
proper ratio due to difference in boiling points
tory solvent since pipecoline reacts with these
and water solubility of the three components.
two materials to form complex dye-like sub
When attempts are made to blend acetone with
stances which are not stable to distillation.
the more selective solvents, such as furfural,
'Acetone is recognized as, an ideal antisolvent
nitrobenzene, phenol, chlorex, pyridine, etc., the
for wax. Wyant and March, Bureau of Mines,
resulting solution has such a low solvent power
Technical paper 368 (1925), found acetone to be
for oil at low dewaxing temperatures that dewax
well adapted to the separation of wax from oil
ing can be carried out only at high temperatures
.and listed among its advantages:
with the production of high pour point oils.
(1) Oil and wax completely soluble in acetone at
Our new group of solvents, the saturated and
100° F.
partially saturated heterocyclic nitrogen bases,
(2) At temperatures below 90° F., the separation
are excellent antisolvents for wax and have a high
of wax and solvent is sharp.
solubility for oil at low temperatures. It is there
(2) One volume of a solvent composed of 60%?
anhydrous picolines mentioned in (1) and
fore possible to blend as much as 40% of acetone
or similar antisolvent for wax with these solvents
to produce a dewaxing solvent which has com
plete solubility for high viscosity index oils at 0°
40% nitro benzene, was mixed with one
volume of the above dewaxed lubricating
oil stock. On cooling, 2. phase separation
occurred at 50° F.
, to --5‘’ F. For example:
( 1) One volume of treated dewaxed Mid-Conti
nent residual lube stock of 90 S. U. V. at
(3) One volume of a solvent composed of 60%
anhydrous pipecolines (hydrogenated pico
210° F. and 85 V. I., was mixed with one
volume of solvent composed of 40% acetone
and 60% pipecolines, prepared by hydro
lines prepared by hydrogenation of the
picoline fraction mentioned in (1) above)
and 40% nitrobenzene, was mixed with one
genating the 240° to 500° F. fraction of
commercial pyridine, which fraction of
volume of the above dewaxed lubricating
oil stock. On chilling, a phase separation
occurred at 0° F.
commercial pyridine is composed substan
tially of picolines. On chilling, a phase
separation occurred at -—5° F.
Thus we are enabled to dewax at temperatures
as low as 0° F. using a blend of 40%‘ nitrobenzene
(2) One volume of treated waxy Mid-Continent
with 60% pipecolines (hydrogenated picolines).
residual lubricating stock, approximately
By so operating, we have greatly extended the
70 S. U. V. at 210° F. and 90 V. 1., was 20 utility of nitrobenzene in solvent dewaxing.
mixed with three volumes of a solvent
This invention is not to be limted in any man
ner by the heretofore given examples which are
for purposes of illustration only. It should be
composed of 40% acetone and 60% pipeco
lines prepared as in above Example I. The
solution was mixed thoroughly, shock
chilled to 0°
?ltered and the solvent
removed by distillation. An oil of 0° F.
pour point was obtained.
understood that the alkyl derivatives of the above
saturated or partly saturated heterocylic nitrogen
compounds are closely related in physical and
chemical properties and that these derivatives
singly or in mixtures which exist in suitable boil
Thus while it is known to mix as much as ¢l0%
ing point range, for example, 240 to 500° F., and
acetone with such. auxiliary solvents as naphtha, 30 melting point range suitable for use at dewaxing
acetone and benzol, such solvents are limited in
temperatures, as to permit separation from oil
use with medium and high V. I. oils to dewaxing
and wax, are satisfactory within degree for use
temperatures above 0° F. Moreover, the benzol
as given.
is non-selective, and is di?icult to keep in solution
Mixtures of these materials and similar mate
at low temperatures. It has not heretofore been
rials are suitable. Such mixtures may be obtained
known to blend as high as 40% acetone with se
lective type solvents for use in dewaxing at 0° F.
and below, due to miscibility considerations.
With our selective solvents comprising large pro
portions of acetone, it is possible to realize all
the advantages of acetone dewaxing without the
disadvantage of low solubility for oil, and at the‘
by hydrogenation of commercial pyridine, pico
lines, quinolines, selected cuts of nitrogen com
pounds from coal tar oils, or hydrogenation of
the nitrogen bases recovered from petroleum.
49 A convenient method of obtaining useful dewax
ing solvents consisting of blends of saturated and
partially saturated heterocyclic nitrogen bases
in pyridine, picoline, quinoline, etc., is to hydro
same time the acetone is assisted in its wax pre
cipitating action by the selective solvent which
has a relatively high antisolvent power for wax.
With these blended solvents, it is possible to pro
genate by conventional methods the said pyridine,
5‘ picoline, quinoline, etc., to such an extent as to
duce low pour point oils with practically no dif
ferential between the dewaxing temperature and
the pour point of the recovered oil. Moreover, the
wax crystals formed from our blended solvent are
distinct, sharp edged, and ?ltration is readily
accomplished at high rates. Thus, as an addi
tional contribution to the art, our invention dis
closes a method wherein the utility of acetone in
produce a mixture comprising hydrogenated and
partially hydrogenated compounds.
The solvent mixtures and solvent concentra
tions may be varied and used in many ways as
will be understood by those skilled in the art.
By increasing the proportions of antisolvent in
the mixtures, the resulting solvent may be used
advantageously for solvent extraction of mineral
oils at convenient temperatures, such as atmos
solvent dewaxing is widely extended.
55 pheric temperatures.
Weir, U. S. Patent 2,154,190, disclosed the use
An example of the use of our solvent for
of blends of 40% nitrobenzene with 60% of an
hydrous pyridine as a dewaxing solvent. This
solvent extraction of a lubricating oil stock is as
blend was claimed to have exceptional properties
A sample of Mid-Continent bright stock was
as a dewaxing solvent since the resulting dewaxed 60 batch extracted at 86° F. with 4 volumes of our
oils were stated to be of lower pour point than
blended solvent (25% pipecoline prepared as
the dewaxing temperatur . He was restricted,
above disclosed, and 75% acetone). Yields and
tests on the stock and resulting products are:
however, to dewaxing temperatures of 45 to 50°
F., and higher, since at lower temperatures an
oil phase separated due to the low solubility of 65
the blend for oil.
Our investigation disclosed the following:
(1) One volume of anhydrous picolines (com
mercial pyridine, dried and fractionated to 70
250° to 300° F.) was mixed with one volume
of treated dewaxed Mid-Continent residual
lubricating oil stock of 90 S. U. V. at 120°
F. and 85 V. I. On chilling, an oil phase
separated at +6° F.
Yield _________________ -_per cent__
S. U. V. at 210° F._
S. U. V. at 100° F__
Viscosity index _________________ _ _
164. 2
3, 460
3, 715
134. 3
3, 025
7. 7
92. 3
Distribution of solvent between
the two phases. _ _____per cent__ ________ _-
It will be noted that by the use of our hydro
genated solvent with acetone, a ra?inate possess
ing markedly improved qualities over those of the
enhancers, as given heretofore, since many mate;
rials and combinations of materials having the
above described characteristics and properties
may be successfully employed in practicing our
invention and yet remain within its intended
original stock was obtained.
A suggested application of solvent extraction
and solvent dewaxing of a lube oil stock with a
solvent comprising a blend of acetone and pipec
oline includes the following steps:
1. Extraction with blended solvent: 75% acetone,
We claim:
1. The process of solvent extraction of mineral
25% pipecoline, prepared as above disclosed.
2. Partial distillation of solvent from the raf?nate 10 oils including the steps of mixing the oil with a
solvent mixture comprising a hydrogenated se
to remove a portion of the acetone, which
lected fraction of commercial pyridine, an anti
solvent, and water, the selected fraction of com
mercial pyridine boiling between the approximate
limits of 240° and 500° F., and the hydrogenated
material consisting essentially of pipecollnes and
the antisolvent being acetone, thereby forming a
raf?nate phase and an extract phase, and sepa
4. Dewaxing of the extracted ra?'inate with said
rating the ra?inate phase from the extract phase.
dewaxing solvent blend.
2. The process of solvent extraction of mineral
The use of regulated quantities of water in se 20 oils including the steps of mixing the oil with a
lective solvents, partially or completely miscible
solvent mixture comprising pipecoline, an anti
with water, for the purpose of regulating the sol
solvent, vand water,-in which mixture the antisol
vent power of the mixture is known. Useful sol
vent is acetone, thereby forming a ra?‘inate phase
vents may be obtained by the use of regulated
and an extract phase, and separating the raflinate
quantities of water in the above listed materials 25 phase from the extract phase.
disclosed in our invention.
We do not wish to be limited by the particular
examples of dewaxing and extraction solvents, or
blends of solvents and antisolvents or solubility
step also removes the water from the raf?
nate solution.
3. Addition of sufficient pipecoline to bring the
solvent composition to that desired for de
waxing, say about 40% acetone and 60% 15
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