JP4943522B2 - High viscosity base oil and method for producing high viscosity base oil - Google Patents

Description

  The present invention relates to process oils and high-viscosity base oils added to natural rubber or synthetic rubber, and methods for producing them, and in particular, because of the low content of polycyclic aromatic compounds, there is no toxicity and carcinogenicity, and handling The present invention relates to an easy rubber process oil and a method for producing the same.

  Rubber process oils are used to facilitate rubber manufacturing operations such as kneading, extrusion, molding, etc., using their permeability to rubber polymer structures. It is also used to improve the physical properties of rubber products. Such rubber process oils must have a suitable affinity for rubber. On the other hand, the rubber to be processed includes natural rubber and synthetic rubber, and there are various types of synthetic rubber. Of these, natural rubber and styrene-butadiene rubber (SBR) are used in large quantities, and rubber process oils containing a large amount of aromatic hydrocarbons and having high affinity for rubber are generally used. Used.

In order to obtain such a rubber process oil, the lubricating oil fraction obtained by vacuum distillation of crude oil or the vacuum distillation residual oil is defoamed and then dewaxed or hydrorefined as necessary. Oil obtained by subjecting the obtained oil to extraction treatment with a solvent having affinity for aromatic hydrocarbons is used. Rubber process oil obtained in this way contains 70 to 99 percent of the aromatic compound according to the column chromatography according to the% C _A value ring analysis (ASTM D 2140) is 20-50%, United Kingdom It contains 5 to 25% by mass of a dimethyl sulfoxide (DMSO) extract corresponding to the content of polycyclic aromatic compound (PCA) as defined by the Petroleum Institute of Japan.

  However, in recent years, the carcinogenicity of PCA has been regarded as important, and in Europe, oil containing 3% or more of DMSO extract is obliged to be toxic and there is a movement to regulate its use. Therefore, there is an urgent need to reduce the DMSO extract of rubber process oil to less than 3%.

  Regarding rubber process oil having a DMSO extract of less than 3%, Japanese Patent Publication No. 6-505524 discloses dewaxing the residue under reduced pressure distillation and dewaxing the resulting oil to obtain a DMSO extract of 3%. Disclosed is a process for producing a reduced rubber process oil. The DMSO extract of the above oil is lower but has a higher aniline point. The aniline point is an indicator of the aromatic hydrocarbon content, and a high aniline point means a low aromatic hydrocarbon content. However, as the aromatic hydrocarbon content in the oil decreases, the affinity of the oil for rubber decreases. Therefore, in what is disclosed in the above publication, the property required for the rubber process oil, that is, the permeability of the rubber process oil to the rubber polymer is lowered. In addition, it becomes difficult to satisfy the physical state of the final rubber product.

  In addition, JP 7-501346 A discloses a non-carcinogenic bright stock extract and / or demineralized oil and a purification process thereof, and in order to reduce the mutagenicity index (MI) to 1 or less, MI It has been proposed to use a property that correlates with the above as an index of purification. In this, the oil obtained by dewaxing the residue in the vacuum distillation column, the oil in which the aromatic compound is reduced by the extraction treatment of the defoamed oil, or the oil obtained by the dewaxing treatment thereof is used. However, the DMSO extract is estimated to be 3% or more. The relationship between MI and DMSO extract of such deoiled oil is not disclosed in the patent.

JP-T 6-505524 JP 7-501346 A

The present invention has been made in order to solve such problems of the prior art, and the object of the present invention is to provide a rubber process oil having a high safety and high permeability to a rubber polymer and having a DMSO extract of less than 3%. Is to provide a new and economical process for producing
In addition, an extract useful as a process oil and a raffinate useful as a high-viscosity base oil are obtained in the process oil production process, and a method for producing a high-viscosity base oil from the latter raffinate and the high-viscosity base oil are provided. It is to be.

In order to achieve the above object, the present inventors have conducted extensive research and found that the DMSO extract is less than 3% under specific distillation / solvent refining conditions, leading to the present invention.
The present invention based on the above findings
1 . In the process of producing an extract useful as a process oil and a raffinate useful as a high-viscosity base oil by solvent refining, vacuum distillation was performed under conditions where the end point of the distillate oil was 580 ° C. or higher in terms of atmospheric pressure. The residual oil is degassed under the condition that the residual carbon content of the deoiled oil is 1.6% or less, the deoiled oil is subjected to solvent refining, and one of furfural, phenol and N-methyl-2-pyrrolidone is used as a solvent. Alternatively, the kinematic viscosity at 40 ° C. obtained after defatting of the raffinate obtained by selecting and using it under the condition that the extract yield is 35 to 60% is 400 mm ² / s to 700 mm ² / s. A high viscosity base oil having a pour point of −5 ° C. or less and a viscosity index of 95 or more,
2 . Distillation under reduced pressure is carried out under the condition that the end point of the distillate is 580 ° C. or higher in terms of atmospheric pressure, and the resulting residual oil is dewaxed under the condition that the residual carbon content of the deoiled oil is 1.6% or less. It is obtained by subjecting camellia oil to solvent refining, selecting one or more of furfural, phenol and N-methyl-2-pyrrolidone as the solvent and using it under conditions where the extract yield is 35-60%. A high-viscosity base oil having a kinematic viscosity at 40 ° C. of 400 mm ² / s or more and 700 mm ² / s or less obtained after degassing of the obtained raffinate, a pour point of −5 ° C. or less, and a viscosity index of 95 or more;
Is to provide.

  According to the production method of the present invention, a process oil having high safety and high permeability to a rubber polymer and a high viscosity base oil can be obtained simultaneously and economically.

  Hereinafter, the present invention will be described in more detail. Process oils can generally be prepared from a lubricating oil fraction obtained from crude oil. The lubricating oil fraction can be obtained as a fraction obtained by distilling the residual oil after atmospheric distillation of the crude oil, or as a degassed oil obtained by removing the residual oil obtained by distilling the crude oil under reduced pressure. Solvent extraction is a method for separating each component from the lubricating oil fraction. If a solvent having a selective affinity for aromatic hydrocarbon compounds is used in the solvent extraction of oil, the aromatic hydrocarbon is separated from the lubricating oil fraction. can do. However, a solvent having a selective affinity for an aromatic hydrocarbon compound has a higher affinity for a polycyclic aromatic compound (PCA). Therefore, when an aromatic hydrocarbon compound is extracted by a general extraction operation, a large amount of the solvent is used. PCA will be included. If PCA can be removed from this extracted oil, a suitable process oil can be obtained, but it is generally difficult and not economical. As a result of studying a process for producing an oil having a small amount of PCA, the present inventors have found that it can be effectively produced by combining specific vacuum distillation conditions and solvent purification conditions.

  The method for producing a rubber process oil according to the present invention comprises treating a defoamed oil fraction obtained by defoaming a distillation residue obtained from crude oil by distillation under reduced pressure with a solvent having affinity for aromatic hydrocarbons, A solvent and an extract (extract) are separated and recovered. In addition, about the raffinate isolate | separated in the case of solvent extraction in this case, a hydrogenation process and a dewaxing process can be performed as needed and it can utilize as a high-viscosity base oil.

  The process oil obtained by the specific production method of the present invention is most suitable as a rubber process oil having a low content of polycyclic aromatic compounds and abundant aromatic hydrocarbons. The DMSO extract used in the present application refers to the content of aromatic compounds extracted with DMSO (dimethyl sulfoxide) according to the IP346 method defined by the British Petroleum Institute. Although some conventional PCA regulations refer to aromatic compounds having three or more rings, the IP346 method is a recognized and standard method for determining the PCA content of oils.

  The rubber process oil obtained in the present invention has a very low content of polycyclic aromatic compounds, but the aromatic hydrocarbon content measured by chromatography is hardly decreased as compared with the conventional rubber process oil. High penetrability to rubber such as rubber and natural rubber. In addition, the rubber process oil of the present invention is a material sufficient to obtain a rubber that can exhibit almost the same physical properties as a rubber product obtained by processing with a conventional process oil containing a large amount of PCA. .

  Hereinafter, embodiments of the production method of the present invention will be described in detail. In order to produce the rubber process oil of the present invention, a degassed oil fraction obtained by degassing a vacuum distillation residue obtained by subjecting a crude oil atmospheric distillation residue to vacuum distillation under a predetermined condition is used as an aromatic hydrocarbon. The extract is obtained in the form of a mixture with the solvent by treating with a solvent having a selective affinity and removing the raffinate. By removing this solvent, a rubber process oil can be obtained.

  As crude oil, various crude oils such as paraffin crude oil, naphthenic crude oil, etc. can be used, and defoamed oil obtained by desulfurization of vacuum distillation residue obtained by distilling atmospheric distillation residue of all kinds of crude oil under reduced pressure. Can do.

  The distillation under reduced pressure is carried out under conditions where the end point of the distillate is 580 ° C. or higher in terms of atmospheric pressure, or under conditions where the initial distillation of the residue is 450 ° C. or higher. When the end point is lower than this temperature, the DMSO extract of the obtained extract becomes high, which is not preferable.

  Next, the residual oil obtained by distillation under reduced pressure is degassed under the condition that the residual carbon content of the degassed oil is 1.6% or less. If the residual carbon content exceeds 1.6%, the PCA in the extract increases, and the oxidation stability of the resulting high viscosity base oil is adversely affected.

  A solvent refining process is performed in which the deoiled oil obtained by the above method is extracted with a solvent having affinity for aromatic hydrocarbons. As the solvent having selective affinity for the aromatic hydrocarbon, one or more selected from furfural, phenol and N-methyl-2-pyrrolidone can be used.

  In this solvent refining process, the extract yield is 35 to 60%. When the extract yield is less than 35%, the DMSO extract is not less than 3%. On the other hand, when the extract yield exceeds 60%, the aromatic content in the extract is reduced and raffinate. Since the yield of the high-viscosity base oil obtained as the above becomes low and the economic efficiency deteriorates, it is not preferable.

  The specific extraction conditions for bringing the extract yield within the above range cannot be determined uniquely because it depends on the deoiled oil composition, but can be adjusted by the solvent ratio, pressure, temperature, etc. is there. In general, the raffinate is removed by contacting with a solvent at a temperature of 60 ° C. or higher, preferably 60 to 155 ° C., solvent / oil ratio (volume ratio) = 2/1 to 7/1. The raffinate can be used as a high-viscosity lubricating base oil by performing a hydrotreating / dewaxing step as necessary.

The extract useful as a process oil in the present invention has a kinematic viscosity at 100 ° C. of 50 to 100 mm ² / s,% C _A (ASTM D2140) 15 to 35%, DMSO extract (IP346) less than 3%, aniline point 90 ° C. Hereinafter, the aromatic content is 60 wt% to 95 wt% by chromatography, and the Mw (weight average molecular weight) is 650 or more. The mutagenicity index MI is less than 1.0.

When the kinematic viscosity at 100 ° C. exceeds 100 mm ² / s, workability when used as a process oil is lowered and the effect of reducing the viscosity of the rubber as the process oil is not sufficient. On the other hand, if the kinematic viscosity at 100 ° C. is less than 50 mm ² / s, it is extremely difficult to make the DMSO extract less than 3%, and the economical efficiency of the purification process is deteriorated.

Further, when% C _A (ASTM D2140) is less than 15%, it may be difficult to produce rubber using the rubber process oil, or physical properties of the rubber product may be deteriorated. On the other hand, if% C _A (ASTM D2140) exceeds 35%, the physical properties of the rubber product may also deteriorate, and it will be extremely difficult to make the DMSO extract less than 3%. This is not preferable because the economy is deteriorated.

  The DMSO extract (IP 346) is less than 3% because it is subject to EU regulation if there is a risk of carcinogenicity if it exceeds 3% as already explained.

  If the aniline point exceeds 90 ° C., the compatibility with the rubber decreases, which is not preferable.

  Moreover, when the aromatic content by chromatography is less than 60%, it may be difficult to produce rubber using the rubber process oil, or the physical characteristics of the rubber product may be deteriorated. On the other hand, if the aromatic content by chromatography exceeds 95%, the physical properties of the rubber product may also deteriorate, and it will be extremely difficult to make the DMSO extract less than 3%. Is not preferable because of worsening.

  If the Mw (weight average molecular weight) is less than 650, it will be extremely difficult to make the DMSO extract less than 3%, and the economical efficiency of the purification process will be unfavorable. A mutagenicity index MI of 1.0 or more is not preferable because of the possibility of carcinogenicity.

  Further, the glass transition point measured by DSC is preferably −70 ° C. or higher because the low loss imparting performance to rubber products is improved. Moreover, -20 degrees C or less is preferable from the point of low-temperature performance.

In addition, the raffinate obtained by the solvent refining process is further subjected to a hydrogenation / dewaxing process, if necessary, so that the pour point is −5 ° C. or less, the viscosity index is 95 or more, and the kinematic viscosity (40 ° C.) is 400 mm ² / s or more and 700 mm. A high viscosity base oil of ² / s or less can be obtained.

  When the production method of the present invention is used, the extract obtained by the first-stage solvent extraction can be directly used as a product. Therefore, compared to the method of performing the second-stage solvent extraction or the secondary treatment such as hydrogenation. Manufacturing costs are reduced. Further, since non-carcinogenic process oil and high viscosity base oil having a viscosity index higher than usual can be obtained at the same time, it is excellent in economic efficiency.

EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example and a comparative example, this invention is not limited to an Example. The measurement items in the present invention were determined by the following method.
[Measurement of Polycyclic Aromatic Compound (PCA) Concentration (DMSO Extract)] The DMSO extract was determined by the IP346 (1992 version) test method.
[Ring Analysis ring analysis% C _A was calculated according to ASTM D 2140-97.
[Kinematic Viscosity] Measured according to JIS K2283-1993.
[Aniline point] Measured according to JIS K2256-1998.
[Mw (weight average molecular weight)] Mw is defined by Mw = ΣMi ² Ni / ΣMiNi (Mi: molecular weight, Ni: number of molecules), and is generally measured by GPC (gel permeation chromatography) or the like.

This time, Mw (polystyrene conversion) was measured by GPC under the following conditions.
Solvent: Tetrahydrofuran Column temperature: 50 ° C
Flow rate: 1.0ml / Min
Column: Shodex GPC KF-805L
Detector: Shimadzu RID-6A
[Pour point] Measured according to JIS C2101-1999.
[Viscosity index] The viscosity index was calculated in accordance with JIS K2283-1993.
[Nitrogen content] Calculated according to JIS K2609-1998.
[Sulfur content] Measured according to JIS K2541-1996.
[Aromatic content by chromatography] Measured in accordance with ASTM D2007-98.
[Mutagenicity index (MI)] Measured according to ASTM E1687-98.
[Gas chromatographic distillation] Measured according to ASTM D2887-97a.
[Residual carbon content] Measured according to JIS K2270-1998.
Example 1
The residue obtained by distilling Arabian light crude oil under reduced pressure so that the end point is (gas chromatographic distillation FBP) 600 ° C. is propane-dehydrated so that the residual carbon content is 1.3% (solvent ratio is 700%, pressure Was 3.3 MPaG, reaction tower 72 ° C.), furfural was used as a solvent, the solvent ratio was set to 400%, and the solvent was extracted so that the extract yield was 42%. The raffinate was further hydrorefined using an alumina catalyst supported by 3% by weight of nickel and 12% by weight of molybdenum (hydrogen pressure: 6.5 MPaG, liquid space velocity (LHSV): 2.5 h ⁻¹ , temperature: 315 ° C. , Desulfurization rate 48%), light components were removed, solvent dewaxing (methyl ethyl ketone: toluene = 1: 1, solvent ratio 330%, cooled to -20 ° C., yield 84%), kinematic viscosity ( 40 ° C.) A high viscosity base oil having 508.4 mm ² / s, a pour point of −10 ° C., and a viscosity index of 101 was obtained. DMSO extractables measured extract by IP346 method 2.7 wt.%,% C _A is 25.3%, a kinematic viscosity (100 ° C.) is 65.26mm ² / s, aniline point 72 ° C., by chromatography The aromatic content was 84% by weight and Mw was 785.
(Comparative Example 1)
The residue obtained by distilling Arabian light crude oil under reduced pressure so that the end point is (gas chromatographic distillation FBP) 600 ° C. is propane-dehydrated so that the residual carbon content is 1.3% (solvent ratio is 700%, pressure Was 3.3 MPaG, the reaction tower temperature was 72 ° C.), the solvent ratio was 350% using furfural as the solvent, and the solvent extraction was performed so that the extract yield was 30%. DMSO extractables measured extract by IP346 method 4.0 wt.%,% C _A is 28.6%, a kinematic viscosity (100 ° C.) is 80.24mm ² / s, aniline point 63 ° C., by chromatography The aromatic content was 86% by weight and Mw was 730.
(Comparative Example 2)
The residue obtained by distilling Arabian light crude oil under reduced pressure so that the end point is (gas chromatographic distillation FBP) 600 ° C. is propane-dehydrated so that the residual carbon content is 1.3% (solvent ratio is 700%, pressure Was 3.3 MPaG, reaction tower 72 ° C.), furfural was used as the solvent, the solvent ratio was 280%, and the solvent was extracted so that the extract yield was 20%. DMSO extractables measured extract by IP346 method 5.3 wt.%,% C _A is 33.5%, a kinematic viscosity (100 ° C.) is 110.6mm ² / s, aniline point 51 ° C., by chromatography The aromatic content was 86% by weight and Mw was 645.
(Comparative Example 3)
The residue remaining after distilling Arabian light crude oil under reduced pressure so that the distilling point is 560 ° C (gas chromatographic distillation FBP) is propane-dehydrated so that the residual carbon content is 1.3% (solvent ratio is 700% The pressure was 3.3 MPaG, the reaction tower was 72 ° C.), and the solvent ratio was 280% using furfural as the solvent, and the solvent was extracted so that the extract yield was 25%. DMSO extractables measured extract by IP346 method 9.9 wt.%,% C _A is 33.6%, a kinematic viscosity (100 ° C.) is 58.33mm ² / s, aniline point 55 ° C., by chromatography The aromatic content was 86% by weight and Mw was 601.

  Table 1 shows the solvent refining conditions of Examples and Comparative Examples, and the properties of the high-viscosity base oils obtained by solvent dewaxing of the obtained extract and raffinate.

Claims (2)

In the process of producing useful raffinate in solvent refining useful extract and a high viscosity base oil as a process oil, subjected to vacuum distillation end point of distillate is Te a condition to be normal pressure terms 580 ° C. or higher, obtained The residual oil was degassed under the condition that the residual carbon content of the deoiled oil was 1.6% or less, the deoiled oil was subjected to solvent refining, and 1 from furfural, phenol and N-methyl-2-pyrrolidone as a solvent. The kinematic viscosity at 40 ° C. obtained after the defatting of the raffinate obtained by performing selection under the condition that the extract yield is 35 to 60% is selected from one or more and from 400 mm ² / s to 700 mm ² / s. A method for producing a high-viscosity base oil, wherein a pour point of a high-viscosity base oil is −5 ° C. or less and a viscosity index is 95 or more. It performs a vacuum distillation end point of distillate is Te in conditions that the atmospheric pressure in terms of 580 ° C. or higher, the residual carbon content of the resulting residual oil deasphalted oil is deasphalted with conditions to be 1.6% or less, By subjecting the deoiled oil to solvent refining and selecting one or more of furfural, phenol and N-methyl-2-pyrrolidone as the solvent and performing the extraction yield under conditions of 35-60%. A high-viscosity base oil having a kinematic viscosity at 40 ° C. of 400 mm ² / s or more and 700 mm ² / s or less, a pour point of −5 ° C. or less, and a viscosity index of 95 or more obtained after deraising of the obtained raffinate.