U.S. patent application number 09/837178 was filed with the patent office on 2001-11-29 for process oil, high-viscosity base oil, and process for the production thereof.
Invention is credited to Fujino, Kenji, Morishima, Yoshiyuki.
Application Number | 20010045377 09/837178 |
Document ID | / |
Family ID | 18628763 |
Filed Date | 2001-11-29 |
United States Patent
Application |
20010045377 |
Kind Code |
A1 |
Morishima, Yoshiyuki ; et
al. |
November 29, 2001 |
Process oil, high-viscosity base oil, and process for the
production thereof
Abstract
A novel process for the production of an extract useful as a
process oil and a raffinate useful as a high-viscosity base oil by
solvent refining is provided, characterized in that reduced
pressure distillation is effected under the condition that the end
point of distillate is 580.degree. C. or higher as calculated in
terms of atmospheric pressure or the initial boiling point of the
residue is 450.degree. C. or higher as calculated in terms of
atmospheric pressure, the resulting residual oil is deasphalted
under the condition that the carbon residue content in the
deasphalted oil reached 1.6% or less, and the resulting deasphalted
oil is subjected to solvent refining under the condition that the
yield of extract is from 35% to 60%. It is a novel and economically
excellent process for the preparation of a rubber process oil
having a high safety, a high penetrating power with respect to
rubber polymer and the content of PCA extract of less than 3%.
Inventors: |
Morishima, Yoshiyuki;
(Toda-shi, JP) ; Fujino, Kenji; (Toda-shi,
JP) |
Correspondence
Address: |
SUGHRUE, MION, ZINN, MACPEAK & SEAS, PLLC
2100 Pennsylvania Avenue, N.W.
Washington
DC
20037
US
|
Family ID: |
18628763 |
Appl. No.: |
09/837178 |
Filed: |
April 19, 2001 |
Current U.S.
Class: |
208/309 ;
208/311; 208/347; 208/41; 208/45 |
Current CPC
Class: |
C10G 53/06 20130101;
C10G 2300/301 20130101; C10G 2300/302 20130101; C10G 2300/44
20130101; C10G 2300/304 20130101; C10M 101/02 20130101; C10G
2400/10 20130101 |
Class at
Publication: |
208/309 ; 208/41;
208/45; 208/311; 208/347 |
International
Class: |
C10C 003/06; C10C
003/08 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 19, 2000 |
JP |
P. 2000-117447 |
Claims
What is claimed is:
1. A process for the production of an extract useful as a process
oil and a raffinate useful as a high-viscosity base oil by solvent
refining, which comprises carrying out reduced pressure
distillation under the condition that the end point of distillate
as converted to the value under atmospheric pressure is 580.degree.
C. or higher or the initial boiling point of the residue is
450.degree. C. or higher as calculated in terms of atmospheric
pressure, deasphalating the resulting residual oil under the
condition that the carbon residue content in the deasphalted oil
reaches 1.6% or less, and subjecting the resulting deasphalted oil
to solvent refining under the condition that the yield of extract
is from 35% to 60%.
2. The production process according to claim 1, wherein said
extract useful as a process oil exhibits a 100.degree. C. dynamic
viscosity of from 50 to 100 mm.sup.2/s, a percent C.sub.A of from
15% to 35%, the content of PCA extract (IP346) of less than 3%, an
aniline point of 90.degree. C. or lower, a
chromatographically-determined aromatic content of from 60% to 95%
by weight and Mw (weight-average molecular weight) of 650 or
more.
3. The production process according to claim 1, wherein the
high-viscosity base oil having a 40.degree. C. dynamic viscosity of
from not lower than 400 mm.sup.2/s to not higher than 700
mm.sup.2/s obtained after the dewaxing of raffinate exhibits a pour
point of not higher than -5.degree. C. and a viscosity index of not
lower than 95.
4. A process oil having a 100.degree. C. dynamic viscosity of from
50 to 100 mm.sup.2/s, a percent C.sub.A of from 15% to 35%, the
content of PCA extract (IP346) of less than 3%, an aniline point of
90.degree. C. or lower, a chromatographically-determined aromatic
content of from 60% to 95% by weight and Mw (weight-average
molecular weight) of 650 or more.
5. The process oil according to claim 4, which has a mutagenicity
index MI of less than 1.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a process oil for the
addition into natural rubber and synthetic rubber and a
high-viscosity base oil, as well as to a process for the production
thereof. More particularly, the present invention relates to a
rubber process oil which has a low content of a polycyclic aromatic
compound so as to exhibit no toxicity or carcinogenicity and can be
easily handled and to a process for the production thereof.
BACKGROUND OF THE INVENTION
[0002] A rubber process oil is used to facilitate the procedure
such as kneading, extrusion and molding in the production of rubber
by exhibiting a penetrating power with respect to rubber polymer
structure. A rubber process oil is also used to improve the
physical properties of rubber products. Such a rubber process oil
is required to have an appropriate affinity for rubber. On the
other hand, examples of rubbers to be processed include natural
rubber and synthetic rubber. There are various synthetic rubbers.
Among these rubbers, natural rubber and styrene-butadiene rubber
(SBR) are often used. Therefore, a rubber process oil having a
large amount of aromatic hydrocarbon and a high affinity for rubber
is normally used.
[0003] The rubber process oil is obtained by extracting a lubricant
fraction obtained by distillation of crude oil under reduced
pressure or an oil obtained by deasphalting reduced pressure
distillation residue with a solvent having an affinity for aromatic
hydrocarbon. The rubber process oil thus obtained contains an
aromatic compound in an amount of from 70% to 99% as determined by
column chromatography, exhibits a percent C.sub.A of from 20% to
50% according to ring analysis (ASTM D2140) and contains the
content of PCA (polycyclic aromatic compound) extract of from 5 to
25% by mass. The content of PCA extract is defined by IP346 method
of British Society of Petroleum.
[0004] However, the carcinogenicity of PCA has recently been
noticed. In Europe, the law stipulates that oils having the content
of PCA extract of 3% or more shall have an indication of toxicity.
There is a movement to regulate the use of these oils. Accordingly,
it is of urgent necessity to reduce the content of PCA extract of
rubber process oil to less than 3%.
[0005] Referring to rubber process oil having the content of PCA
extract of less than 3%, JP-W-6-505524 discloses a process for the
production of a rubber process oil having the content of PCA
extract of less than 3% which comprises deasphalting the residue of
distillation under reduced pressure, and then dewaxing the oil thus
obtained (the term "JP-W" means a published Japanese translation of
a PCT application).
[0006] The foregoing oil has the low content of PCA extract but has
a high aniline point. The aniline point is an index of the content
of aromatic hydrocarbon. A high aniline point means a low aromatic
hydrocarbon content. However, when the content of aromatic
hydrocarbon in an oil is decreased, the resulting oil exhibits a
lowered affinity for rubber. Therefore, the rubber process oil
disclosed in the above cited patent publication exhibits
deterioration of properties required for rubber process oil, i.e.,
penetrating power with respect to rubber polymer. Further, it is
made difficult to provide the final rubber product with
satisfactory physical conditions.
[0007] JP-W-7-501346 discloses a noncarcinogenic bright stock
extract and/or deasphalted oil and a process for the production
thereof, and proposes to use characteristics related to
mutagenicity index (MI) as an index of purification to reduce MI to
1 or less. In this case, an oil obtained by deasphalting the
residue in a vacuum distillation column, an oil having a reduced
aromatic compound content obtained by extracting a deasphalted oil
or an oil obtained by dewaxing the foregoing oil is used. However,
it is considered that the content of PCA extract is 3% or more. The
relationship between MI and the content of PCA extract of such a
deasphalted oil is not disclosed in the above cited patent
publication.
[0008] The present invention is to solve the foregoing problems. It
is therefore an object of the present invention to provide a rubber
process oil having a high safety, a high penetrating power with
respect to rubber polymer and the content of PCA extract of less
than 3% and a novel and economically excellent process for the
preparation thereof.
SUMMARY OF THE INVENTION
[0009] As a result of extensive studies to achieve the foregoing
object of the invention, the present inventors found that the
content of PCA extract reaches less than 3% under specific
distillation and solvent refining conditions. The present invention
has thus been accomplished.
[0010] Based on the above finding, the present invention
provides:
[0011] 1. A process for the production of an extract useful as a
process oil and a raffinate useful as a high-viscosity base oil by
solvent refining, which comprises
[0012] carrying out a reduced pressure distillation under the
condition that the end point of distillate as converted to the
value under atmospheric pressure is 580.degree. C. or higher or the
initial boiling point of the residue is 450.degree. C. or higher as
calculated in terms of atmospheric pressure,
[0013] deasphalating the resulting residual oil under the condition
that the carbon residue content in the deasphalted oil reaches 1.6%
or less, and
[0014] subjecting the resulting deasphalted oil to solvent refining
under the condition that the yield of extract is from 35% to
60%.
[0015] 2. The production process according to 1 above, wherein the
extract useful as a process oil exhibits a 100.degree. C. dynamic
viscosity of from 50 to 100 mm.sup.2/s, a percent C.sub.A of from
15% to 35%, the content of PCA extract (IP346) of less than 3%, an
aniline point of 90.degree. C. or lower, a
chromatographically-determined aromatic content of from 60% to 95%
by weight and Mw (weight-average molecular weight) of 650 or
more.
[0016] 3. The production process according to 1 above, wherein the
high-viscosity base oil having a 40.degree. C. dynamic viscosity of
from not lower than 400 mm.sup.2/s to not higher than 700
mm.sup.2/s obtained after the dewaxing of raffinate exhibits a pour
point of not higher than -5.degree. C. and a viscosity index of not
lower than 95.
[0017] 4. A process oil having a 100.degree. C. dynamic viscosity
of from 50 to 100 mm.sup.2/s, a percent C.sub.A of from 15% to 35%,
the content of PCA extract (IP346) of less than 3%, an aniline
point of 90.degree. C. or lower, a chromatographically-determined
aromatic content of from 60% to 95% by weight and Mw
(weight-average molecular weight) of 650 or more.
[0018] 5. The process oil according to 4 above, which has a
mutagenicity index MI of less than 1.
DETAILED DESCRIPTION OF THE INVENTION
[0019] The present invention will be further described
hereinafter.
[0020] In general, a process oil can be prepared from petroleum,
particularly from a lubricant fraction derived from crude oil, as a
starting material. The lubricant fraction can be obtained as a
fraction when the residue obtained by atmospheric distillation of
crude oil is distilled under reduced pressure or as a deasphalted
oil when the residue obtained by reduced pressure distillation of
atmospheric residue is deasphalted. As a method for separating the
constituents of the lubricant fraction from each other there is
used solvent refining. When the lubricant fraction is subjected to
solvent refining with a solvent having a selective affinity for an
aromatic hydrocarbon compound, the aromatic hydrocarbon can be
separated from the lubricant fraction. The extract thus obtained
contains a large amount of high boiling point aromatic
compounds.
[0021] Since a solvent having a selective affinity for an aromatic
hydrocarbon has a higher affinity for PCA than for an aromatic
hydrocarbon, the aromatic hydrocarbon extracted by ordinary
extraction method contains a large amount of PCA. If PCA can be
removed from the extract, a suitable process oil can be
obtained.
[0022] The inventors conducted studies of process for the
production of an oil having a reduced content of PCA. As a result,
it was found that an oil having a reduced content of PCA can be
effectively produced by combining specific distillation and solvent
refining conditions.
[0023] In accordance with embodiments of the process for the
production of the rubber process oil according to the present
invention, a lubricant fraction obtained by reduced pressure
distillation of crude oil or a deasphalted oil fraction obtained by
deasphalting the atmospheric or reduced pressure distillation
residue of crude oil is treated with a solvent having an affinity
for aromatic hydrocarbon. The solvent and the resulting extract are
then separated and recovered. The raffinate separated during the
solvent extraction may be subjected to hydrogenation/dewaxing, if
necessary, and used as a high-viscosity base oil.
[0024] The process oil obtained by each of these embodiments of the
production of the rubber process oil according to the present
invention is the most suitable rubber process oil having a lower
content of polycyclic aromatic compound but rich with aromatic
hydrocarbon.
[0025] The conventional definition of PCA may include an aromatic
compound having three or more cycles, but the IP346 method is an
ordinary and standard method approved as a method for determining
PCA content in oil material.
[0026] Since the rubber process oil obtained according to the
production process of the present invention has an extremely low
content of polycyclic aromatic compounds but shows little or no
decrease in the chromatographically-determined aromatic hydrocarbon
content as compared with the conventional rubber process oil. Thus,
the rubber process oil of the present invention has a high
penetrating power with respect to rubber such as SBR rubber and
natural rubber and thus does not lower the workability of rubber.
In addition, the rubber process oil of the present invention is a
material which can provide a rubber exhibiting physical properties
of the almost same level as that of rubber products obtained by
treatment with a conventional process oil containing much PCA.
[0027] Embodiments of the production process of the present
invention will be further described hereinafter.
[0028] In order to produce a rubber process oil of the present
invention, crude oil is subjected to atmospheric distillation. The
atmospheric residue is then subjected to reduced pressure
distillation. The resulting residue is then deasphalted. The
deasphalted oil fraction thus obtained is then treated with a
solvent having a selective affinity for aromatic hydrocarbon to
remove raffinate therefrom. In this manner, an extract is obtained
in the form of mixture with the solvent. A rubber process oil can
be obtained by removing the solvent from the mixture.
[0029] Deasphalted oils obtained by deasphalting the residue of
distillation under reduced pressure of the atmospheric residue of
various crude oils such as paraffin oil and naphthalene oil can be
preferably used.
[0030] The reduced pressure distillation may be carried out under
the condition that the end point of distillate is 580.degree. C. or
higher as calculated in terms of atmospheric pressure or the
initial boiling point of the residue is 450.degree. C. or higher as
calculated in terms of atmospheric pressure.
[0031] The end point of distillate which is lower than 580.degree.
C. is not preferable, because the resulting extract would have the
high content of PCA extract.
[0032] Subsequently, the residue obtained by reduced pressure
distillation is deasphalted under the condition that the carbon
residue content in the deasphalted oil reached 1.6% or less. The
carbon residue content in the deasphalted oil exceeding 1.6% is not
preferable, because the resulting extract would have an increased
PCA content and the oxidation stability of the high-viscosity base
oil obtained as a raffinate would be adversely influenced.
[0033] The deasphalted oil thus obtained is then subjected to
solvent refining, i.e., extraction with a solvent having an
affinity for aromatic hydrocarbon. Examples of the solvent having a
selective affinity for aromatic hydrocarbon include furfural,
phenol or N-methyl-2-pyrrolidone, singly or in combination of
selected two or more thereof.
[0034] The solvent refining is effected under the condition that
the yield of extract becomes from 35% to 60%. The solvent refining
under the condition that the yield of extract falls below 35% is
not preferable, because the content of PCA extract would not fall
below 3%. On the contrary, the solvent refining under the condition
that the yield of extract exceeding 60% is not preferable, because
the resulting extract would exhibit a reduced aromatic content and
the yield of the high-viscosity base oil obtained as a raffinate
would be reduced to lower the economy.
[0035] Specific extraction conditions under which the yield of
extract falls within the above defined range depend on the
composition of the deasphalted oil to be processed and thus cannot
be unequivocally determined. In practice, however, the extraction
conditions can be adjusted by the solvent ratio, pressure,
temperature, etc.
[0036] In general, the deasphalted oil is brought into contact with
the solvent at a temperature of generally 60.degree. C. or higher,
preferably from 60.degree. C. to 155.degree. C., and a solvent/oil
ratio of about 2/1 to 7/1 (by volume) to remove the raffinate
-therefrom. The raffinate thus removed may be subjected to
hydrogenation/dewaxing as necessary so that it is used as a
high-viscosity lubricating base oil.
[0037] The extract useful as a process oil in the present invention
exhibits a 100.degree. C. dynamic viscosity of from 50 to 100
mm.sup.2/s, a percent C.sub.A (ASTM D2140) of from 15% to 35%, the
content of PCA extract (IP346) of less than 3%, an aniline point of
90.degree. C. or lower, a chromatographically-determined aromatic
content of from 60% to 95% by weight and Mw (weight-average
molecular weight) of 650 or more. The extract also exhibits a
mutagenicity index MI of less than 1.
[0038] The 100.degree. C. dynamic viscosity of the extract
exceeding 100 mm.sup.2/s is not preferable, because the extract
exhibits a lowered workability when used as a process oil and the
extract does not exert a sufficient effect of lowering viscosity
with respect to rubber when used as a process oil. On the contrary,
the 100.degree. C. dynamic viscosity of the extract falling below
50 mm.sup.2/s is not preferable, because it becomes extremely
difficult to reduce the content of PCA extract to less than 3% and
the economical efficiency of refining process is lowered.
[0039] When the percent C.sub.A (ASTM D2140) of the extract falls
below 15%, it would be difficult to produce a rubber using a rubber
process oil and there is a possibility that the resulting rubber
products have deteriorated physical properties. On the contrary,
when the percent C.sub.A (ASTM D2140) exceeds 35%, there is a
possibility that the resulting rubber products have deteriorated
physical properties similarly to the case where the percent C.sub.A
(ASTM D2140) falls below 15% and it might be extremely difficult to
reduce the content of PCA extract to less than 3% and the
economical efficiency of refining process is lowered.
[0040] The content of PCA extract (IP346) should be below 3%
because the content of PCA extract of 3% or more conflicts with EU
regulations for the reason that it can be carcinogenic.
[0041] The aniline point of the extract exceeding 90.degree. C. is
not preferable, because the affinity to a rubber is lowered.
[0042] When the chromatographically-determined aromatic content of
the extract falls below 60%, there is a possibility that the
production of a rubber using a rubber process oil becomes difficult
and that the resulting rubber products have deteriorated physical
properties. On the contrary, when the
chromatographically-determined aromatic content of the extract
exceeds 95%, there is a possibility that the resulting rubber
products have deteriorated physical properties and it would be
difficult to reduce the content of PCA extract to less than 3% and
the economical efficiency of refining process is lowered.
[0043] The Mw (weight-average molecular weight) of the extract
falling below 650 is not preferable, because it would be extremely
difficult to reduce the content of PCA extract to less than 3% and
the economical efficiency of refining process is lowered.
[0044] When the mutagenicity index MI of the extract is 1.0 or
more, the resulting product can be carcinogenic and thus it is not
preferable.
[0045] The glass transition point of the extract determined by a
differential scanning calorimeter (DSC) is preferably not lower
than -70.degree. C. because the resulting extract exerts an
improved effect of providing the rubber products with reduced loss.
From the standpoint of low temperature properties, the glass
transition point of the extract is preferably not higher than
-20.degree. C.
[0046] The raffinate obtained by solvent refining is optionally
performed to hydrogenation/dewaxing to obtain a high-viscosity base
oil having a pour point of not higher than -5.degree. C., a
viscosity index of not lower than 95 and a dynamic viscosity
(40.degree. C.) of from 400 mm.sup.2/s to 700 mm.sup.2/s.
[0047] In accordance with the production process of the invention,
the extract obtained by the one-step solvent extraction can be used
as a product as it is, making it possible to reduce the production
cost as compared with the two-step solvent extraction process or
the process required second step such as hydrogenation.
[0048] The production process of the invention makes it possible to
obtain a noncarcinogenic process oil and a high-viscosity
lubricating base oil, VI of which is higher than usual at the same
time, giving an excellent economy.
[0049] The present invention will be further described-in the
following examples, but the present invention should not be
construed as being limited thereto.
[0050] The various properties of the invention were determined
according to the following methods.
[0051] Measurement of concentration of polycyclic aromatic compound
(PCA):
[0052] The content of PCA extract was determined by IP346 testing
method (edition of 1992).
[0053] Ring analysis:
[0054] The ring analysis percent C.sub.A was calculated according
to ASTM D 2140-97.
[0055] The dynamic viscosity was measured according to the method
defined in JIS K2283-1993.
[0056] Aniline point:
[0057] The aniline point was measured according to the method
defined in JIS K2256-1998.
[0058] Mw (weight-average molecular weight):
[0059] Mw is defined as .SIGMA.Mi.sup.2Ni/.SIGMA.MiNi (Mi:
molecular weight; Ni: number of mols). Mw is generally measured by
GPC (gel permeation chromatography).
[0060] Mw was measured by GPC under the following conditions (in
polystyrene equivalence).
[0061] Solvent: Tetrahydrofuran
[0062] Column temperature: 50.degree. C.
[0063] Flow rate: 1.0 ml/min.
[0064] Column: Shodex GPC KF-805L
[0065] Detector: Shimadzu RID-6A
[0066] Pour point:
[0067] The pour point was measured according to the method defined
in JIS C2101-1999.
[0068] Viscosity index:
[0069] The viscosity index was calculated according to the method
defined in JIS K2283-1993.
[0070] Nitrogen content:
[0071] The nitrogen content was calculated according to the method
defined in JIS K2609-1998.
[0072] Sulfur content:
[0073] The sulfur content was measured according to the method
defined in JIS K2541-1996.
[0074] Chromatographically-determined aromatic content:
[0075] The chromatographically-determined aromatic content was
measured according to the method defined in ASTM D2007-98.
[0076] Mutagenicity index (MI):
[0077] The mutagenicity index (MI) was measured according to the
method defined in ASTM E1687-98.
[0078] The gas chromatographic distillation was measured according
to the method fined in ASTM 2887-97a.
[0079] The carbon residue content was measured according to the
method defined in JIS K2270-1998.
EXAMPLE 1
[0080] The atmospheric residue of Arabian light crude oil was
distilled under reduced pressure until the end point (gas
chromatographic distillation FBP) reached 600.degree. C. The
resulting residue was then deasphalted with propane (solvent ratio:
700%; pressure: 3.3 MPaG; reaction column temperature: 72.degree.
C.) so that the carbon residue content reached 1.3%. The
deasphalted oil was then subjected to solvent extraction with
furfural as a solvent at a solvent ratio of 400% so that the yield
of extract reached 42%.
[0081] The raffinate thus obtained was subjected to purification by
hydrogenation in the presence of an alumina-based catalyst having 3
wt % of nickel and 12 wt % of molybdenum supported thereon
(hydrogen pressure: 6.5 MPaG; liquid hourly space velocity (LHSV):
2.5 h.sup.-1; temperature: 315.degree. C.; desulfurization rate:
48%) to remove light contents therefrom, and then subjected to
solvent dewaxing (methyl ethyl ketone: toluene=1:1; solvent ratio:
330%; cooled to -20.degree. C.; yield: 84%) to obtain a
high-viscosity base oil having a dynamic viscosity (40.degree. C.)
of 508.4 mm.sup.2/s, a pour point of -10.degree. C. and a viscosity
index of 101.
[0082] The extract thus obtained exhibited the content of PCA
extract of 2.7% by mass as measured by IP346 method, a percent
C.sub.A of 25.3%, a dynamic viscosity (100.degree. C.) of 65.26
mm.sup.2/s, an aniline point of 72.degree. C., a
chromatographically-determined aromatic content of 84% by weight
and MW of 785.
COMPARATIVE EXAMPLE 1
[0083] The atmospheric residue of Arabian light crude oil was
distilled under reduced pressure until the end point (gas
chromatographic distillation FBP) reached 600.degree. C. The
resulting residue was then deasphalted with propane (solvent ratio:
700%; pressure: 3.3 MPaG; reaction column temperature: 72.degree.
C.) so that the carbon residue content reached 1.3%. The
deasphalted oil was then subjected to solvent extraction with
furfural as a solvent at a solvent ratio of 350% so that the yield
of extract reached 30%.
[0084] The extract thus obtained exhibited the content of PCA
extract of 4.0% by mass as measured by IP346 method, a percent
C.sub.A of 28.6%, a dynamic viscosity (100.degree. C.) of 80.24
mm.sup.2/s, an aniline point of 63.degree. C., a
chromatographically-determined aromatic content of 86% by weight
and MW of 730.
COMPARATIVE EXAMPLE 2
[0085] The atmospheric residue of Arabian light crude oil was
distilled under reduced pressure until the end point (gas
chromatographic distillation FBP) reached 600.degree. C. The
resulting residue was then deasphalted with propane (solvent ratio:
700%; pressure: 3.3 MPaG; reaction column temperature: 72.degree.
C.) so that the carbon residue content reached 1.3%. The
deasphalted oil was then subjected to solvent extraction with
furfural as a solvent at a solvent ratio of 280% so that the yield
of extract reached 20%.
[0086] The extract thus obtained exhibited the content of PCA
extract of 5.3% by mass as measured by IP346 method, a percent CA
of 33.5%, a dynamic viscosity (100.degree. C.) of 110.6 mm.sup.2/s,
an aniline point of 51.degree. C., a chromatographically-determined
aromatic content of 86% by weight and MW of 645.
COMPARATIVE EXAMPLE 3
[0087] The atmospheric residue of Arabian light crude oil was
distilled under reduced pressure until the end point (gas
chromatographic distillation FBP) reached 560.degree. C. The
resulting residue was then deasphalted with propane (solvent ratio:
700%; pressure: 3.3 MPaG; reaction column temperature: 720.degree.
C.) so that the carbon residue content reached 1.3%. The
deasphalted oil was then subjected to solvent extraction with
furfural as a solvent at a solvent ratio of 280% so that the yield
of extract reached 25%.
[0088] The extract thus obtained exhibited the content of PCA
extract of 9.9% by mass as measured by IP346 method, a percent
C.sub.A of 33.6%, a dynamic viscosity (100.degree. C.) of 58.33
mm.sup.2/s, an aniline point of 55.degree. C., a
chromatographically-determined aromatic content of 86% by weight
and MW of 601.
[0089] The conditions under which solvent refining was conducted in
these examples and comparative examples and the properties of the
high-viscosity lubricating base oils obtained by solvent dewaxing
of the resulting extracts and raffinates are set forth in Table 1
below.
1 TABLE 1 Comparative Comparative Comparative Example Example
Example Example 1 1 2 3 Process Gas chromatographic 500 600 600 560
oil distillation FBP Solvent ratio 400 350 280 280 Yield (%) 42 30
20 25 Density (15.degree. C.) g/cm.sup.3 0.9716 0.9853 1.0094
0.9994 Dynamic viscosity 226.7 304.9 485.4 213.5 (75.degree. C.)
mm.sup.2/g Dynamic viscosity 65.26 80.24 110.6 58.33 (100.degree.
C.) mm.sup.2/g Nitrogen content mass-% 0.11 0.14 0.15 0.16 Aniline
point (.degree. C.) 72 63 51 55 PCA extract 2.7 4.0 5.3 9.9 mass-%
Mw (weight-average 785 730 645 601 molecular weight) Refractive
index (nD20) 1.5432 1.5522 1.5671 1.5634 VGC 0.9005 0.9160 0.9535
0.9464 RI 1.0589 1.0611 1.0639 1.0652 % C.sub.A 25.3 28.6 33.5 33.6
Aromatic content wt-% 84 86 86 86 Glass transition point -45 -42
-42 -42 (.degree. C.) Mutagenicity index (MI) <1 <1 <1
.gtoreq.1 High- Density (15.degree. C.) g/cm.sup.3 0.8940 0.8977
0.9011 -- viscosity Dynamic viscosity 508.4 520.9 510.7 -- base
(40.degree. C.) mm.sup.2/g oil Dynamic viscosity 34.12 33.91 33.00
-- (100.degree. C.) mm.sup.2/g Viscosity index 101 98 97 -- Sulfur
content mass-% 0.50 0.61 0.75 -- Aniline point .degree. C. 128 124
122 -- Pour point .degree. C. -10 -10 -10 --
[0090] As mentioned above, the production process of the invention
makes it possible to obtain a process oil having a high safety and
a high penetrating power with respect to rubber polymer and a
high-viscosity base oil at the same time and a reduced cost.
[0091] While the invention has been described in detail and with
reference to specific embodiments thereof, it will be apparent to
one skilled in the art that various changes and modifications can
be made therein without departing from the spirit and scope
thereof.
[0092] This application is based on Japanese patent application No.
2000-117447, filed on Apr. 19, 2000, and incorporated herein by
reference.
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