JPH0660315B2 - Lubricating base oil composition and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a lubricating base oil composition having a high viscosity and pressure coefficient suitable for lubricating mechanical elements used in an elastohydrodynamic lubrication region, and a method for producing the same. .

[Prior Art] Many mechanical elements are used in an elastohydrodynamic lubrication region where the coefficient of friction is minimized. In this elastohydrodynamic lubrication region, the pressure generated on the contact surface becomes extremely high, and the viscosity of the lubricant exponentially increases with this increase in pressure, so the oil film is maintained even under high pressure and the contact surface is separated. It is said to be possible.

However, in mechanical elements actually used, such as sliding bearings with low speed and high load, rolling bearings with medium load or more, it is unavoidable that part of them will be in a boundary friction state, and the oil film will break, resulting in metal-to-metal contact. As a result, the contact surface is damaged, and phenomena such as increased friction and pitting occur, which shortens the life of the mechanical element.

It is known that the lubricating oil is effective against such a phenomenon, and the thicker the oil film of the lubricating oil entering the contact surface is, the more the metal-to-metal contact is prevented, and as a result, the life required for the machine is extended. It is known that this oil film thickness is proportional to the normal pressure viscosity of the lubricating oil and the viscosity / pressure coefficient if the operating conditions of the machine are constant. However, if the atmospheric viscosity is increased, the movement of the mechanical elements is hindered due to the viscous resistance of the lubricating oil itself, resulting in stirring loss, resulting in heat generation and an increase in the friction coefficient, which is not preferable in terms of energy saving. However, in the widely used mineral oils and various synthetic oils, the viscosity and pressure coefficient are small, and the atmospheric viscosity is increased more than necessary to obtain the oil film thickness. Is occurring.

In order to prevent metal-to-metal contact against such problems, it is desired to develop an inexpensive construction method capable of further reducing the surface roughness of the mechanical element, but it has not been realized yet. Further, a lubricating oil capable of forming an effective oil film even with a low viscosity has not been developed yet.

By the way, it is known that the viscosity and pressure coefficient of naphthenic mineral oil are larger than that of paraffinic mineral oil, but the absolute value is 20 centistokes (cst, 17 ° C).
It is about 20 gigapascal (G · Pa), which is not satisfactory. Also, among various synthetic oils developed for so-called traction drives, those having high viscosity and pressure coefficient are known, but this kind of synthetic oil originally aims to improve the tensile coefficient between rotating members. The friction coefficient on the contact surface of the mechanical element is large as can be easily inferred from its application, there is a problem from the viewpoint of energy saving to use it for normal lubrication, and the viscosity grade that can be supplied. There is also a problem that it is expensive and expensive.

In view of such a viewpoint, the inventors of the present invention have earnestly studied the relationship between the molecular structure of the lubricating oil and the physical properties thereof, and the total of the ring-constituting carbon of the condensed polycyclic alicyclic compound and the carbon directly bonded to the ring. Is 80% or more of the total carbon, and the total of the fused 3-ring alicyclic compound and the fused 4-ring alicyclic compound is 40% or more, and the ratio of the both is within the range of 1: 6 to 2: 1. If there,
The present invention has been achieved by finding that it exhibits extremely high viscosity and pressure coefficient.

[Problems to be Solved by the Invention] That is, an object of the present invention is to provide a lubricating base oil composition which is inexpensive and has a high viscosity / pressure coefficient. The purpose of the present invention is to provide a lubricating base oil composition having a pressure coefficient over a wide range of viscosities, and further to provide a lubricating base oil having not only a high viscosity / pressure coefficient but also excellent oxidation stability. It is to be.

Another object of the present invention is to provide a method for producing a lubricating base oil composition having the above characteristics,
Another object of the present invention is to provide a method capable of efficiently and inexpensively producing a lubricating base oil composition having the above-mentioned characteristics from readily available raw materials.

[Means for Solving the Problems] Accordingly, the present invention is obtained by nuclear hydrogenating a feedstock oil containing a condensed polycyclic aromatic compound, and provides a ring-constituting carbon of the condensed polycyclic alicyclic compound and its ring. The total number of carbons directly bonded is 80% or more of the total carbon, the total of the condensed 3-ring alicyclic compound and the condensed 4-ring alicyclic compound is 40% or more, and the ratio of both is 1: 6.
The present invention provides a lubricating base oil composition in the range of ˜2: 1, and the present invention also comprises distilling, pyrolyzing and hydrocracking a feedstock containing a condensed polycyclic aromatic compound. The total number of carbon atoms in the ring and carbons directly bonded to the ring is 8
It is 0% or more, the total amount of the condensed 3-ring compound and the condensed 4-ring compound is 40% or more, and the ratio of the both is within the range of 1: 6 to 2: 1, and a hydrocarbon oil obtained is produced. The present invention provides a method for producing a lubricating base oil composition for nuclear hydrogenation of hydrogen oil.

First, in the first invention, as the alicyclic compound constituting the lubricating base oil composition, a condensed 3-ring alicyclic compound and a condensed 4-ring alicyclic compound of the condensed polycyclic alicyclic compounds are used. The total is 40% or more, more preferably 60% or more, and the ratio of both is in the range of 1: 6 to 2: 1, more preferably 1: 6 to.
It is within the range of 1: 1. Condensed bicyclic alicyclic compounds (for example, decalin derivatives) and fused polycyclic alicyclic compounds having 5 or more rings may be present in the lubricating base oil composition within a range not exceeding 60%. If the content of the condensed bicyclic alicyclic compound is too large, the flash point of the lubricating base oil composition is lowered and its use is restricted, which is not preferable.
If the content of the fused polycyclic alicyclic compound having 5 or more rings is too large, the viscosity at atmospheric pressure becomes too high, which is not preferable from the viewpoint of energy saving.

Furthermore, a non-fused polycyclic alicyclic compound having a monocyclic alicyclic structure or a structure in which two or more are linked by a single carbon-carbon single bond or a single methylene chain has a viscosity / pressure coefficient Even if it is high, it is not preferable to include a large amount of it because the friction coefficient is large. Carbon belonging to this structure accounts for 20% of the total carbon.
Hereafter, it is preferably 10% or less.

According to the research conducted by the present inventors, a lubrication having a high viscosity and pressure coefficient such that the total of ring-constituting carbons of a condensed polycyclic alicyclic compound and / or carbons directly bonded to the ring occupies most of all carbons. When an oil base oil composition is mixed with a lubricating base oil composition having a low viscosity / pressure coefficient, the viscosity / pressure coefficient of the mixture is more influenced by the lubricating base oil composition having a lower viscosity / pressure coefficient. It turned out to be strongly received. Therefore, the carbon belonging to the chemical structure that does not contribute to the improvement of the viscosity and the pressure coefficient is less than 20% of the total carbon in the lubricating base oil composition of the present invention,
It is preferably less than 10%. Specifically, carbon belonging to a chain alkyl carbon (around 14.1 ppm, around 19.7 ppm, and 22.7 ppm by ¹³ C-NMR analysis).
(Near, 29.7ppm, 32.0ppm) total is 1
It is desirable to be 5% or less, preferably 10% or less. When the total carbon belonging to the chain alkyl carbon deviates from this range, the viscosity / pressure coefficient rapidly decreases.

Further, the lubricating base oil composition of the present invention is preferably one which does not substantially contain carbon belonging to the ring-constituting carbon of the aromatic compound from the viewpoint of its oxidation stability, and it is measured by ¹³ C-NMR analysis. The total amount of carbons belonging to the ring-constituting carbons of the aromatic compound is 1% or less, preferably less than the detection limit, based on the total carbons in the composition. In this case, the smaller the carbon belonging to the ring-constituting carbon of the aromatic compound, the better, and this point is significantly different from mineral oils in which the optimum range for the aromatic compound content exists in order to obtain excellent oxidative stability. It is a different point.

Next, in the second invention, examples of the feedstock oil containing a condensed polycyclic aromatic compound used as a feedstock include, for example, coal carbonized oil such as coal tar produced as a by-product during the production of coke for iron making, and various types of coal liquefaction. Oil, catalytically cracked decant oil, catalytically cracked heavy recycled oil and the like can be mentioned, but preferably coal carbonized oil or coal liquefied oil because it is easy to obtain a highly condensed polycyclic structure, and more preferably unnecessary. It is a coal tar that is by-produced during high-temperature carbonization of coal because it does not contain much alkyl chains and in some cases the step for removing alkyl groups such as thermal decomposition can be omitted.

In the method of the present invention, when any of the above feedstocks is used, when the feedstock is distilled, pyrolyzed or hydrocracked, it is directly attached to the ring-constituting carbon of the aromatic compound or alicyclic compound or its ring. It is necessary to provide a hydrocarbon oil in which carbon belonging to any of the carbons to be bonded accounts for 80% or more, preferably 90% or more, of the total carbon. The ratio of carbon belonging to either ring-constituting carbon in the hydrocarbon oil or carbon directly bonded to the ring is 80%
When the amount is smaller, a step of removing the chain alkyl carbon after the nuclear hydrogenation is required to obtain the lubricating base oil composition of the present invention, which is a cost disadvantage.

In the hydrocarbon oil thus obtained, the sulfur compound derived from the raw material oil is usually 0.0 in terms of elemental sulfur content.
It is contained in an amount of 2 to 2% by weight, and a nitrogen compound is contained in an amount of 0.1 to 3% by weight in terms of elemental nitrogen content. However, regarding the sulfur content and the nitrogen content, the next nuclear hydrogenation process is smoothly performed. In order to carry out the sulfur content preferably by hydrorefining
The amount of nitrogen is set to 00 ppm or less and the nitrogen content is set to 1,000 ppm or less.

Hydrorefining of hydrocarbon oils carried out for this purpose can be carried out, for example, by M
Batch type in the presence of a catalyst in which at least one metal component selected from Group VI or Group VIII metals such as o, W, Ni, Co, etc. is supported on a carrier such as alumina or silica. Or a flow system, but a flow system is preferred, and the reaction conditions in this case are a reaction temperature of 200 to
500 ° C., preferably 350-400 ° C., reaction pressure 20-300 kg / cm ² · G, preferably 50-20
0 kg / cm ² · G, liquid hourly space velocity (LHSV) is 0.1
It is 10.0 hr ^-1 , and the liquid-gas ratio is 100 to 5,
It is a _000-H 2 / -oil. In order to efficiently obtain the lubricating base oil composition of the present invention, it is necessary to avoid side reactions such as cracked gasification as much as possible, and from this viewpoint, the reaction temperature is preferably 400 ° C or lower.

The hydrocarbon oil, which is desulfurized and denitrogenated as required, and is refined to have a sulfur content of 100 ppm or less and a nitrogen content of 1,000 ppm or less, is then subjected to nuclear hydrogenation. This nuclear hydrogenation is carried out, for example, with N
It can be carried out batchwise or in a flow system in the presence of a catalyst containing at least one metal component selected from metals of Group VIII of the periodic table such as i, Pt, Ru, etc., but preferably in a flow system. The reaction conditions in this case are that the reaction temperature is 50 to 300 ° C., preferably 150 to 250 ° C.
Reaction pressure is 50 to 300 kg / cm ² · G, preferably 50
~ 200 kg / cm ² · G, liquid hourly space velocity (LHSV) 0.1 ~ 10.0 hr ^-1 , liquid-gas ratio 10
Is a _0~5,000-H 2 / -oil.

Further, for the purpose of removing impurities remaining in the hydrocarbon oil, purification treatment by sulfuric acid washing treatment and / or solid adsorption treatment may be carried out before and / or after the nuclear hydrogenation, if necessary. At this time, either of these processes may be performed, or both processes may be performed. In the case of performing both processes, the order is arbitrary and one of the processes is the core. It may be carried out before the hydrogenation and the other treatment may be carried out after the nuclear hydrogenation.

The product oil produced by nuclear hydrogenation and optionally purified by sulfuric acid washing treatment and / or solid adsorption treatment is separated into fractions having an appropriate boiling point range by distillation, preferably vacuum distillation, or By appropriately blending the thus obtained fractions, it is possible to obtain a lubricating base oil composition having a high viscosity and pressure coefficient in various atmospheric viscosity ranges.

The lubricating base oil composition of the present invention is not only useful as a general-purpose lubricating oil used for various machine elements, but can also be used for special applications such as bearing oil, gear oil, and refrigerating machine oil. .

[Examples] Hereinafter, the present invention will be specifically described based on Examples.

Example 1 High-temperature dry distillation coal tar was distilled under reduced pressure to obtain a boiling point of 35 at atmospheric pressure.
A hydrocarbon oil of 0 to 480 ° C was obtained. This hydrocarbon oil is
As a result of ¹³ C-NMR analysis, the total ratio of the ring-constituting carbon of the aromatic compound and the carbon directly bonded to the ring was 97% with respect to the total carbon.

Next, a commercially available Ni-Mo / Al ₂ O ₃ catalyst is used in a flow-type reactor, and the hydrocarbon oil is reacted at a reaction temperature of 40.
0 ℃, reaction pressure 180kg / cm ² · G, liquid space velocity (LHS
V) 0.2 hr ^-1 and liquid-gas ratio 1,000-H ₂ /
Hydrorefining was carried out under the condition of -oil. In this hydrorefining, the carbon loss due to gasification during the reaction was 1% or less, the sulfur content of the obtained hydrorefined oil was 20 ppm, and the nitrogen content was 650 ppm.

Further, the hydrotreated oil was treated with activated clay under the conditions of 120 ° C. and liquid hourly space velocity (LHSV) of 1 hr ⁻¹ , and then commercially available N
i / diatomaceous earth catalyst was used as a flow reactor, and the hydrogenated refined oil treated with activated clay was used at a reaction temperature of 22
0 ℃, reaction pressure 180kg / cm ² · G, liquid space velocity (LHS
V) 0.3 hr ^-1 and liquid-gas ratio 1,500-H ₂ /
Nuclear hydrogenation was performed under the condition of -oil to obtain nuclear hydrogenated oil.

The nuclear hydrogenated oil obtained was distilled under reduced pressure to obtain a boiling point of 30 at atmospheric pressure.
Fractionation into 10 fractions between 0 and 430 ° C, mixing each fraction at an appropriate ratio, and preparing 4 viscosity grades (ISO VG: 10, 2
2, 54 and 100) lubricant base oil compositions were prepared.
Regarding the obtained lubricating base oil composition of each viscosity grade,
Ratio of total (C _Γ + C _α ) of ring-constituting carbon and carbon directly bonded to the ring to total carbon, ratio of carbon (C _alkyl ) belonging to chain alkyl carbon to total carbon, aromatic compound to total carbon Carbon belonging to ring-constituting carbon (C
_aroma. ) ratio, viscosity / pressure coefficient (high pressure falling ball viscometer), and oxidation stability. The results are shown in Table 1.

Example 2 Four kinds of viscosity grade lubricating base oil compositions were prepared in the same manner as in Example 1 except that the reaction temperature at the time of nuclear hydrogenation was 230 ° C., and each viscosity grade lubricating base oil composition was prepared. The sum of the ring-constituting carbons and the carbons directly bonded to the ring (C _Γ
+ C _α ), carbon belonging to chain alkyl carbon (C
The ratio of _alkyl ), the ratio of carbon (C _aroma. ) belonging to the ring-constituting carbon of the aromatic compound, the viscosity / pressure coefficient, and the oxidation stability were examined. The results are shown in Table 1.

Example 3 A soft pitch obtained by distilling high-temperature dry distillation coal tar was hydrotreated in the presence of a hydrogenation catalyst, and the obtained hydrogenated pitch was pyrolyzed by a delayed coker to obtain a hydrocarbon oil.

The hydrocarbon oil, the flow reactor that Ni-Mo / _Al 2 _{O 3} catalyst is filled, the reaction temperature 400 ° C., a reaction pressure 1
The hydrorefining was carried out under the conditions of 80 kg / cm ² G, liquid hourly space velocity (LHSV) 0.2 hr ⁻¹ and liquid-gas ratio of 1,000-H ₂ / -oil. The hydrogenated refined oil thus obtained had a sulfur content of 1.5 ppm and a nitrogen content of 45 ppm. A portion of this hydrorefined oil was dehydrogenated with a platinum catalyst for analysis,
As a result of measurement by ¹³ C-NMR analysis and H-NMR analysis,
In this dehydrogenated oil, the ring constituent carbon and α of the aromatic compound
The total carbon content was 93% based on the total carbon.

Next, using a flow reactor filled with a Ru / Al ₂ O ₃ catalyst, the hydrogenated refined oil was treated at a reaction temperature of 200 ° C., a reaction pressure of 180 kg / cm ² · G, and a liquid hourly space velocity (LHSV) of 0. 5 hr
¹ and the liquid-gas ratio _1,000-H 2 / nuclear hydrogenation under the conditions of -Oil, to obtain a nuclear hydrogenated oil.

Based on the obtained nuclear hydrogenated oil, 4 was prepared in the same manner as in Example 1.
Of various viscosity grades of the lubricating base oil composition, and for each viscosity grade of the lubricating base oil composition, the ratio of the ring-constituting carbon and the total carbon (C _Γ + C _α ) directly bonded to the ring,
Ratio of carbon (C _alkyl ) belonging to chain alkyl carbon,
Carbon belonging to ring-constituting carbon of an aromatic compound (C _aroma. )
The ratio, viscosity / pressure coefficient, and oxidative stability were investigated. The results are shown in Table 1.

Example 4 A coal liquefied oil obtained from Moell brown coal was pyrolyzed by a delayed coker, and the obtained pyrolyzed oil was distilled under reduced pressure to obtain a hydrocarbon oil having a boiling point of 350 to 500 ° C at atmospheric pressure.

Next, a commercially available Ni-Mo / Al ₂ O ₃ catalyst is used in a flow-type reactor, and the hydrocarbon oil is reacted at a reaction temperature of 40.
0 ℃, reaction pressure 150kg / cm ² · G, liquid space velocity (LHS
V) 0.3 hr ^-1 and liquid-gas ratio 500-H ₂ / -oil
Hydrorefining was carried out under the conditions of. The hydrorefined oil thus obtained had a sulfur content of 15 ppm and a nitrogen content of 180 ppm. A part of this hydrorefined oil was dehydrogenated with a platinum catalyst for analysis and measured by ¹³ C-NMR analysis and H-NMR analysis. Was 86% of the total carbon.

Next, 10% by weight of Ru / C catalyst was added to the hydrorefined oil and charged in an autoclave at a reaction temperature of 18
Hydrogenation was carried out at 0 ° C. and hydrogen pressure of 140 kg / cm ² · G for 10 hours to obtain a nuclear hydrogenated oil.

The nuclear hydrogenated oil obtained is distilled under reduced pressure to obtain a boiling point of 300 at atmospheric pressure.
Fractionation into 6 fractions between ˜450 ° C., mixing each fraction at an appropriate ratio to prepare a lubricating base oil composition of four viscosity grades in the same manner as in Example 1, and preparing each viscosity grade. Of the lubricating base oil composition, the ratio of the total of the ring-constituting carbon and the carbon directly bonded to the ring (C _Γ + C _α ), the ratio of carbon (C _alkyl ) belonging to the chain alkyl carbon, and the ring of the aromatic compound. The ratio of carbon (C _aroma. ) _Belonging to the constituent carbons, the viscosity / pressure coefficient and the oxidation stability were examined. The results are shown in Table 1.

Comparative Examples 1 and 2 A naphthene-based mineral oil was used as Comparative Example 1, and a paraffin-based mineral oil was used as Comparative Example 2, and the same four types of viscosity base oil base oil compositions as in each of the above Examples were prepared. The sum of the ring-constituting carbons and the carbons directly attached to the rings (C _Γ +) for each viscosity grade lubricating base oil composition prepared.
C _α ), carbon belonging to the chain alkyl carbon (C
_Alkyl ) ratio, viscosity / pressure coefficient and oxidative stability were investigated. The results are shown in Table 1.

[Effects of the Invention] The lubricating base oil composition of the present invention is inexpensive and
It has a high viscosity and pressure coefficient, and not only exhibits excellent lubricating performance, but also a high viscosity over a wide range of normal pressure viscosity.
It exhibits a pressure coefficient and is also excellent in oxidative stability.

Further, according to the method for producing a lubricating base oil composition of the present invention, a lubricating base oil composition having the above-mentioned features can be efficiently produced at low cost from easily available raw materials.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C10N 40:30 60:02 (56) References JP-A-58-154799 (JP, A) JP-A JP-A-62-184095 (JP, A) JP-A-62-148597 (JP, A) JP-A-62-148596 (JP, A) JP-A-64-2785 (JP, A)

Claims (6)

[Claims] 1. A ring-containing carbon of a condensed polycyclic alicyclic compound obtained by nuclear hydrogenation of a feedstock oil containing a condensed polycyclic aromatic compound, and the total of carbons directly bonded to the ring is 80 total carbons.
% Or more, the total of the fused 3-ring alicyclic compound and the fused 4-ring alicyclic compound is 40% or more, and the ratio of both is 1: 6 to 2:
The lubricating base oil composition is characterized in that it is in the range of 1. 2. The total of carbon constituting the ring-constituting carbon and carbon directly bonded to the ring obtained by distilling, pyrolyzing and hydrolyzing a feedstock containing a condensed polycyclic aromatic compound is 80% or more, Producing a hydrocarbon oil in which the total of the condensed 3-ring compound and the condensed 4-ring compound is 40% or more, and the ratio of both is within the range of 1: 6 to 2: 1, and the obtained hydrocarbon oil is subjected to nuclear hydrogenation. A method for producing a lubricating base oil composition, comprising: 3. Hydrodesulfurization and denitrification of hydrocarbon oil by hydrorefining to obtain a sulfur content of 100 ppm or less and a nitrogen content of 1,00.
Claim 2 in which nuclear hydrogenation is carried out after the concentration is reduced to 0 ppm or less.
A method for producing the lubricating base oil composition according to the item. 4. The hydrorefining is carried out at a reaction temperature of 200 to 500 ° C. under a reaction pressure of 200 to 500 ° C. in the presence of a catalyst containing at least one metal component selected from metals of Group VI or Group VIII of the periodic table. 20-300 kg / cm ² · G, liquid space velocity 0.1-10.
The method for producing a lubricating base oil composition according to claim 3, which is carried out under the conditions of 0 hr ^-1 and a liquid-gas ratio of 100 to 5,000-H ₂ / -oil. 5. A reaction temperature of 50 to 300 ° C. and a reaction pressure of 20 to 300 in the presence of a catalyst containing at least one metal component selected from metals of Group VIII of the periodic table for nuclear hydrogenation.
kg / cm ² · G, liquid space velocity 0.1 to 10.0 hr ⁻¹ , liquid ·
Preparation of gas ratio 100 to 5,000-H ₂ / range the second term of the claims conducted in -oil conditions or lubricant base oil composition of paragraph 3 wherein. 6. The method of producing a lubricating base oil composition according to claim 2, wherein the feedstock oil is coal carbonized oil or coal liquefied oil.