SK277757B6 - Liquid lubricating composition and method of its manufacturing - Google Patents

Abstract

Liquid lubricating composition consists of alkanes or alkenes with 3 to 1300 atoms of carbon with branching ratio lower than 0,19, weight of middle molecular weight 300 to 45000, numerous middle molecular weight 300 to 18000, distribution of molecular weights 1 to 5, flowing temperature under -15 degrees of Celsius viscous index upper 130 and kinematic viscosity at 100 degrees of Celsius to 750 mm/exp-2/.s/exp-1/. Lubricating composition contains alkanes 9-methyl-11-octylhenicosane and 11-octyldocosane. Lubricating compositions are produced that way, that alpha-olefin is introduced with carrier solid catalyst containing reduced metal from group VI.B ( for example chromium ) on oligomerization conditions at temperature about 90 to 250 degrees of Celsius and by arise of liquid hydrocarbon of lubricate type which can be hydrogenated.

Description

Technical field

The invention relates to novel lubricating compositions and in particular to new synthetic lubricating compositions made from alpha-olefins (1-alkenes). The novel synthetic lubricating compositions of the invention made from 1-alkenes exhibit improved viscosity index and have improved and other properties that are important in useful lubricating oils. The invention also relates to a process for the manufacture of these lubricating compositions.

BACKGROUND OF THE INVENTION

For at least fifty years, the research and development of the oil industry has been attempting to obtain, by oligomerization of hydrocarbons, liquids that would exceed their lubricating properties based on naturally occurring mineral oils. This effort resulted in the relatively recent introduction of a large number of excellent synthetic polyalpha-olefin (PAO) lubricants, which are mainly produced by the oligomerization of alpha-olefins (1-alkenes). In an effort to improve the lubricating properties of these lubricants, industrial research has emphasized that synthetic lubricating fluids have a useful viscosity over a wide temperature range, i. i.e., to have an improved viscosity index (VI), while at the same time having a lubricity, heat and oxidation stability, and a freezing point that is equal to or better than mineral oils. These new synthetic lubricants reduce friction and thus increase mechanical efficiency across a range of different types of mechanical loads ranging from worm gears to rope drives and are applicable over a wider range of operating conditions than mineral oil based lubricants.

The main interest of chemists engaged in the development of synthetic lubricants was focused on the polymerization of 1-alkenes. The relationships between the structure and properties of high molecular weight polymers, which were well known in various fields of polymer chemistry, have become a prerequisite for directing research into oligomer synthesis with a structure which was believed to be a prerequisite for achieving improved lubricating properties, specifically to the alkene region. The mechanism of polymerization of 1-alkenes and the effect of this mechanism on the structure of polymers are relatively well elucidated, in particular due to the study of polymerization of propylene and vinyl monomers, and have therefore become an important source of knowledge to focus on potentially useful oligomerization methods and oligomer structures. Using this knowledge, oligomers of 1-alkenes having 6 to 20 carbon atoms have been made in the prior art, and 1-decene oligomers produced by either cationic polymerization or Ziegler-Natta-catalysed polymerization which have significantly exceeded other lubricants have proved to be the most commercially commercial synthetic lubricants. of this type.

Oligomerization, for example 1-decene, to lubricating oligomers containing 30 to 40 carbon atoms can theoretically lead to a very large number of structural isomers. Henze and Blair (JACS 54.1538) calculated that there are more than 60 x 10 ¹² isomers of C ₃ to C ₄₀ . The discovery of precisely these isomers, which would exhibit the desired preferred properties of synthetic lubricants, and hence meet, inter alia, the specific requirements for wide temperature in-flow fluidity, while maintaining a low pour point and developing appropriate oligomerization procedures, is a huge task for those skilled in the art. An example of a structure compatible with structures believed to have excellent low temperature fluidity, characterized by the atoms being centered near the center of the carbon atom chain, is Brennan (Ind. Eng. Chem. Prod. Res. Dev. 1980, 19, 2-6) 1-decene trimer. It is also reported that the properties of the oligomer are obviously dependent on the oligomerization method used, i.e., cationic polymerization or polymerization using Ziegler catalysts, which are well known and used in the art.

One of the structural properties of the molecules of the 1-alkene oligomers, which has been found to be highly correlated with improved lubricating properties of commercially available synthetic lubricants, is the ratio of methyl groups to methylene groups in the oligomer. This ratio is referred to as the branching ratio and can be calculated from infrared data as described in Standard Hydrocarbons of High Molecular Weight, Analytical Chemistry, Vol. 25, no. 10, p. 1466 (1953). The viscosity index was found to increase with decreasing branching ratio. To date, oligomeric liquid lubricants having a very low branching ratio have not been synthesized from 1-alkenes. For example, oligomers prepared from 1-decene by both cationic polymerization and polymerization using Ziegler catalysts have a branching ratio greater than 0.20. Shubkin (Ond. Eng. Chem. Prod. Res. Dev. 1980, 19, 15-19) provides an explanation for the apparent existence of a limitation of the branching ratio values based on a cationic polymerization mechanism involving branching rearrangement. Other theories explain the reason for branching by isomerization of the olefinic group at the 1-position, which leads to the formation of internal olefins. It is clear that oligomerization of 1-alkenes to obtain synthetic lubricants, as it has been done hitherto, results in excessive branching, which limits the achievable properties of the lubricant, particularly as regards the viscosity index, regardless of whether this branching occurs. it occurs as a result of rearrangement, isomerization or other mechanism not yet elucidated. The increased branching range appears to result in the formation of a greater number of isomers in the oligomeric mixture, so that the mixture departs from a structure that would be considered preferred in the light of the theoretical considerations set forth above.

U.S. Pat. 282,392 discloses Cupples and another synthetic alpha-olefin oligomer based lubricant having an improved viscosity-volatility relationship and containing a high proportion of tetramer and pentamer, a scaffold hydrogenation process and isomerization. The claimed substance has no trimer / tetramer ratio higher than 1: 1. The branching ratio is not shown here.

A method for producing high molecular weight polymers from 1-alkenes using a coordination catalyst, in particular a chromium catalyst on silica as a carrier, has been described by Weiss et al. In Jour. Catalysis 88, 424-430 (1984) and DE (DOS) 3,427,319. This production method and the products obtained therein are characterized in greater detail below as compared to the method and products of the invention.

It is well known that Lewis acids, such as boron trifluoride and / or metal halides, may be present

The activator will catalyze Friedel-Crafts-type reactions. However, olefin oligomers, and in particular oligomers of the polyalphaolefin type, are produced by processes that readily isomerize the double bond of the starting 1-olefin. As a result, olefin oligomers have multiple short side branches. These side chains impair their lubricating properties.

Liquid hydrocarbon lubricants having a surprisingly high viscosity index (VI) have been obtained by oligomerization of 1-alkenes having 6 to 20 carbon atoms, at the same time surprisingly very low pour point.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION The present invention relates to a liquid lubricating composition comprising alkanes or alkenes of 30 to 1300 carbon atoms with a branching ratio of less than 0.19, a weight average molecular weight of 300 to 45,000, a number average molecular weight of 300 to 18. 000, a molecular weight distribution of 1 to 5, a pour point below -15 ° C, a viscosity index above 130 and a kinematic viscosity at 100 ° C to 750 m ^{/ s} .

In the context of the invention, a novel 11-octyldocosan has also been discovered which has a structure

HI CH _{3 -} (CH ₃ ) ₁₀ -C (CH 3) _g -CH ₃ (CH ₃ )?

This substance has been found to have excellent lubricating properties, either alone or in admixture with 9-methyl-lloctylheneicosane. Surprisingly, the mixture has a viscosity index higher than 130, preferably 130 to 280, the melting point remaining below -15 ° C. These substances are representative products of the invention which include alkanes of the general formula C ₃₀ H ₆₂ with a branching ratio (CH ₃ / CH ₂ ) below 0.19, preferably in the range of 0.10 to 0.16. These low branching and melting point ratios are characteristic of the compounds of the invention and give the products of the invention, referred to by the abbreviation HVI-PAO (poly-alpha-olefins with high viscosity index), particularly high viscosity index values compared to commercially available synthetic lubricants. of available poly-alpha-olefins (PAO).

The unique lubricating oligomers of the present invention can also be produced over a wide range of molecular weights and viscosities containing C ₃₀ to ΰ, οοο hydrocarbons having a branching ratio below 0.19 and a molecular weight distribution ranging from about 1.05 to 2.5. . Oligomers can be blended with conventional mineral oils or fats to provide compositions with excellent lubricant properties.

Lubricants according to the invention can be prepared by oligomerization of alpha-olefins, such as 1-decene, which are contacted with a Group VI.B metal oxide support catalyst according to the IUPAC periodic table in a reduced valence state under oligomerization conditions. The preferred oxide is chromium oxide.

The invention also relates to a process for the production of liquid olefin oligomers, such as 1-decene with a branching ratio below 0.19, having a higher viscosity index than oligomers with a higher branching ratio. These low branching oligomers can be used as raw materials for many lubricants or greases with improved viscosity-temperature relationship, improved oxidation stability, volatility, etc. They can also be used to improve the viscosity and viscosity index of lower quality oils. For example, the olefins can be oligomerized on a supported catalyst that is a reduced Group VI.B metal oxide of the periodic table to form oligomers suitable for application in lubricants. In particular, the invention relates to a process for the oligomerization of C 6 -C 20 olefinic hydrocarbons, wherein the reaction product consists essentially of non-isomerized olefins. For example, they may be alpha-olefins, such as 1-decene, in which most of the double olefinic bonds are not isomerized, the oligomerization being carried out in the presence of a suitable catalyst, such as a reduced Group VI.B metal oxide on the support.

The use of a Group VI.B reduced metal oxide catalyst as chromium on an inert support for the oligomerization of liquid olefins suitable for use as high-quality lubricating oils is a new technology.

BRIEF DESCRIPTION OF THE DRAWINGS

In FIG. 1 is a comparison of PAO synthesis with HVI-PAO. In FIG. 2 shows a comparison of the viscosity index (VI) of PAO and HVI-PAO. In FIG. 3 shows the pouring temperatures of PAO and HVI-PAO. In FIG. 4 is a C-13 NMR spectrum of HVI-PAO from 1-hexene (Cr / SiO ₂ catalyst). Figure 5 shows the C-13 NMR spectrum of HVI-PAO with a kinematic viscosity of 5 mm ² s ^-1 made from 1-decene. In FIG. 6 is a C-13 NMR spectrum of HVI-PAO with a kinematic viscosity of 50 mm @ ^{-1 / s} made of 1-decene. In FIG. 7 is a C-13 NMR spectrum of HVI-PAO with a kinematic viscosity of 145 mm ² s ^-1 made from 1-decene. In FIG. 8 is a gas chromatogram of HVIPAO which is the trimer of 1-decene. In FIG. 9 shows the C-13 NMR spectrum of HVI-PAO, which is a trimer of 1 decene. In FIG. 10 shows the chemical shift values of HVI-PAO, which is the trimer of 1-decene. This is a comparison of the values calculated from the C-13 NMR spectrum with the observed values.

When used in the following description of HVI-PAO oligomers or lubricants, unless otherwise indicated, hydrogenized oligomers or lubricants are understood in accordance with the practice well known to those skilled in the art. The HVI-PAO oligomers obtained in oligomerization are mixtures of dialkylvinylidene and 1,2 dialkyl or trialkylmonoolefins. Unsaturated lower molecular weight oligomers are preferably hydrogenated to provide thermal and oxidative useful lubricants. Higher molecular weight unsaturated HVI-PAO oligomers are sufficiently thermally stable so that they can be used without hydrogenation and hydrogenation can be omitted if desired. As well as unsaturated hydrogenated lower or higher molecular weight HVI-PAOs, they have a viscosity index of at least 130, preferably in the range of 130 to 280, and a pour point below -15 ° C, preferably below -45 ° C.

Referring to FIG. 1, the novel oligomers of the present invention, i.e., high viscosity index poly-alpha-olefins (HVI-PAO), are illustratively described in comparison to conventional poly-alpha-olefins (PAO) from 1-decene. Polymerization using the novel reduced chromium catalyst described below results in an oligomer that is not substantially isomerized at the double bond. In contrast, in the production of conventional PAO catalyzed by boron trifluoride or aluminum chloride, a carbonium ion is formed which catalyzes the isomerization of the olefinic bond and the formation of many isomers. The HVI-PAO produced according to the invention has a structure such that its branching CH ₃ / CH ₂ ratio is less than 0.19 compared to a value above 20 for PAO.

In FIG. 2 shows a comparison of the viscosity index versus the viscosity of HVI-PAO lubricants with PAO-type lubricants, showing that HVI-PAO significantly exceeds PAO at all viscosities tested. It is noteworthy that despite the more regular structure that the HVI-PAO oligomers have (which is evident from the branching ratio), which results in an improved viscosity index IVI), they also have a better pour point compared to PAO as regards regular-containing oligomers containing fewer isomers would be expected to have higher pour points (pour points) that would reduce their usefulness as lubricants. Surprisingly, this is not the case with the HVI-PAO of the present invention. 2 and 3 illustrate the superiority of HVI-PAO, both at pour point and viscosity index.

The process for the production of the novel HVI-PAO oligomers of the present invention can be controlled to obtain oligomers having a weight average molecular weight in the range of 300 to 45,000 and a number average molecular weight in the range of 300 to 18,000. , the molecular weight may range from C ₃₀ to C _{13 WI} . The kinematic viscosity can be up to 750 mm ² s ^-1 at 100 ° C. The preferred range of carbon atoms is C ₃₀ to C 1 ₃₀₀ The preferred kinematic viscosity is up to 500 mm ² · s ^-1 at 100 ° C and preferably lies in the range of 3 to 750 mm ² · s ^-1 . The molecular weight distribution, defined as the ratio of the weight average molecular weight to the number average molecular weight, ranges from 1.00 to 5. More preferably, it is 1.01 to 3 and even more preferably 1.05 to 2.5. Compared to the conventional PAO obtained by polymerizing 1-alkene using boron trifluoride or aluminum chloride as a catalyst, the HVI-PAOs of the present invention contain a higher proportion of higher molecular weight polymerization molecules in the product.

The viscosity of the new HVI-PAO oligomers measured at 100 ° C ranges from 3 to 500 mm ² s ^-1 . The viscosity index of the new poly-alpha-olefins is approximately described by the following equation:

VI = 129.8 + 4.58 x _{(lw. C)} ⁰ · ^5, wherein W | oo C is kinematic viscosity in mm ² s' ^1, measured at 100 ° C.

The novel oligomeric compounds of the invention have also been subjected to other investigations than to determine their important properties, such as branching ratio and molecular weight, in order to define their unique structure. The dimer and trimer fractions were separated by distillation and their components were further separated by gas chromatography. These lower oligomers and components, as well as the entire reaction mixtures of HVI-PAO oligomers, were studied by infrared spectroscopy and C-13 NMR. These studies have confirmed that the products of the invention have a highly uniform structural composition, particularly as compared to conventional poly-alpha-olefins produced using catalysts such as boron trifluoride, aluminum chloride and Ziegler-type catalysts. The excellent ability of the C-13 NMR to identify structural isomers has led to the identification of prominent compounds in the lower oligomeric fractions and confirmed that the higher molecular weight oligomers are a more uniform isomeric mixture, consistent with the measured low branching ratio and high viscosity values. index.

It has been shown that the 1-hexane-based HVI-PAO oligomers of the present invention have very uniform linear C side chains (branches), with the individual monomer units being regularly oriented head-to-tail. In addition to regular head-to-foot structures, the backbones also contain a proportion of head-to-head units. The structure of the following oligomers can be confirmed by NMR spectroscopy:

!! (-CH-CH 2 -) - (-CH, -CH-) ² H ^{2 x 2} 1 y (CH 2), (CH 2),, 2 J 2 J ch ₃ ch ₃

The NMR spectral data of poly (1-hexene) is shown in FIG. 4th

Oligomerization of 1-decene with a chromium-based supported catalyst in a reduced valence state also yields HVI-PAO having an analogous structure to the 1-hexene oligomer. After distillation of the light fractions and hydrogenation, the lubricants have characteristic C-13 NMR spectra. In FIG. Figures 5, 6 and 7 show the C-13 NMR spectra of typical HVI-PAO type lubricants with a viscosity of 5; 50 and 145 mm ² s ^-1 at 100 ° C.

NMR data referring to FIG. 5 are shown in Table A, NMR data referring to FIG. 6 shows the Table B and NMR data relating to FIG. 7 are shown in Table C.

Table A (Figure 5)

point poaun (ppa) intensity width 1 79.096 136641 2.74 2 74.855 130653 4.52 3 42,394 146620 6.68 4 40,639 133441 37.6 5 40,298 163676 3? 4 6 40,054 176339 31.2 7 39,420 134904 37.4 8 37,714 445452 7.38 9 37,373 227254 157 10 37,081 145467 166 11 36,786 153096 184 12 36,593 145661 166 13 36,447 1J2292 189 14 36,057 152778 184 15 35,619 2o6141 184 16 35,082 505413 26.6 17 34,351 741424 14.3 18 34,059 1265077 7.65 19 32,207 535156B 1.46 20 30,403 3563751 4.3 * 21 29,965 8294773 2.56 22 29,623 4714955 3.67 23 28,356 369728 10.4 24 28,161 305678 13.2 25 26,991 1461260 4.66 26 22,897 4546162 1.76 27 20,265 227694 1.99 26 14,221 4592991 1.62

Table B (Figure 6)

1 1,196.98 79.147 1656 2 1,157.95 77,004 1040 3 1,126.46 74,910 1025 4 559,57 37,211 491 5 526.61 35,019 605 6 514.69 34,240 1296 7 599.76 33,899 1140 8 491.45 32,681 897 9 482.66 32,097 9279 10 456.29 30,344 4972 11 468,24 29,808 9711 12 444.58 29,564 7463 13 426.26 2B.347 1025 14 401.36 26,691 1690 15 342.77 22,794 9782 16 212.40 14,124 B634 17 0.00 0,000 315

Table C (Figure 7)

point Doeun intensity width (Hz) 1 76,903 627426 2.92 2 40,811 901505 22.8 3 40,568 865686 23.1 4 40,32+ 823178 19.5 5 37,138 677621 183 6 36,915 705894 181 7 36,720 669037 183 6 36,428 691870 183 9 36,233 69632J 181 10 35,259 1313574 155 11 35,015 1471226 152 12 34,333 1901096 121 13 32,726 1990364 120 14 32,141 20319110 2.81 15 31,362 1661594 148 16 30,388 9516199 19.6 17 25,901 17778892 9.64 18 29,609 18706236 9.17 19 28,391 1869681 122 20 27,514 1117864 173 21 26,735 2954012 14.0 22 22,839 20895526 2.17 23 14,169 16670130 2.06

In general, the new oligomers have the following head-to-tail structure, where n represents the number 3 to 17:

- (ciu-ch) 2 µx (CH-) _n

I ^{2 n} CH ₃ wherein they also contain some of the head-to-head connections.

The 1-decene HVI-PAO oligomer trimmer is separated from the oligomerization mixture by distillation. From the HVI-PAO with a kinematic viscosity of 20 mm Ts ^-1 , this trimer is distilled off at a temperature range of 165 to 210 ° C at a pressure of 13.3 to 26.6 Pa using a short distillation distillation apparatus. Non-hydrogenated trimer has the following viscometric properties: Kinematic viscosity (A) at 40 ° C is 14.88 mm ² s '', W _{L00 »c} is 3.67 mm ² s ^-1 and a viscosity index (VI) is the 137th

The trimer was hydrogenated at 235 ° C and 4.2 MPa of hydrogen using a nickel-on-silica hydrogenation catalyst. The hydrogenated HVIPAO trimmer obtained has the following characteristics: V ₄₀ <. _c = 16.66 mm ² s'', W _{IOO C} 3.91 mmis' ^1, VI = 133, pour point (mp) - below 45 ° C.

Trimer analysis by gas chromatography shows that it consists mainly of two components whose retention times are 1810 s and 1878 s under the following conditions: gas chromatograph with 60 m capillary column; 0.32 mm ID; a stationary phase coating of SPB-1 with a film thickness of 0.25 mm; Supelco Chromotography Supplies, catalog number 2-4046.

Separation conditions: Varian Gas model no. 3,700, colored by a flame ionization detector and a capillary injector port with a cleavage ratio of about 50. The flow rate of nitrogen as the carrier gas is 2.5 ml.min ^-1 . The injector inlet temperature is 300 ° C, the detector inlet temperature is 330 ° C. The column temperature is first set at 45 ° C (6 minutes), then heated to a final temperature of 300 ° C at a programmed rate of 15 ° C.min ·, and this temperature is maintained for 60 minutes. The sample size is 1 μΐ. Under these conditions, the retention time gc of the dodecane standard is 968 seconds. A typical chromatogram is shown in FIG. 8th

The C-13 NMR spectrum (Figure 9) of the distilled C ₃₀ product confirms the chemical structure. C-13 NMR data for FIG. 9 are shown in Table D.

Table D (Fig. 9) Coaun (approx.) Intensity Width (Ht)

1 55,987 11080 2.30 2 42,632 13367 140 3 42,388 16612 263 4 37,807 40273 5.90 5 37,319 12257 16.2 6 36,539 11374 12.1 7 35,41b 11631 35.3 b 35,126 33099 3.14 9 34,638 3927 14.6 10 34,054 110899 3.32 11 33,615 12544 34.9 12 33,469 1369b 34.2 13 32,981 11278 5.69 14 32,835 13785 57.4 15 32,201 256181 1.41 16 31,811 17867 24.6 17 31,470 13327 57.4 18 30,398 261859 3.36 19 29,959 543993 1.89 20 29,618 317314 1.19 21 28,838 11325 15.1 22 28,351 24926 12.4 23 28,156 29663 6.17 24 27,230 44024 11.7 25 26,966 125437 -0.261 26 22,892 271278 1.15 27 20,260 17578 -22.1 28 14,167 201979 2.01

The assignment of the individual peaks of the C-13 spectrum is shown in FIG. 9. Based on these structures, the chemical shift values are calculated in good agreement with the observed values (see Figure 10). The chemical shift values of the hydrocarbons are calculated as described in Carbon-13 NMR for Organic Chemists, G. C. Levy and G. L. Nelson, 1972, eds. John Wiley and Sons, Inc., Chapter 3, p. 38-41. The components were identified as 9-methyl-11-octylheneicosan and 11 octyldocosan by infrared and C-13 NMR analysis and were found to be present in a ratio of 1:10 to 10: 1 (heneicosan: docosane). The hydrogenated 1-decene trimmer produced by the process of the invention has a refractive index at 60 ° C of 1.4396.

Surprisingly, the process of the present invention provides a simpler and more useful dimer compared to the dimer produced by oligomerization of .alpha.-alkene by boron trifluoride or aluminum chloride which is lo, a substantial portion of the non-hydrogenated sizing 1-alkene has a vinylidene structure of the general formula.

CH ₂ = CR 1 R ₂ , wherein R 1 and R ₂ are alkyl groups which are residues of the addition of 1-alkene molecules in the capsule configuration.

Thus, for example, with respect to the 1-decene dimer of the invention, only three major components have been identified by gas chromatography analysis. C-13 NMR analysis revealed that the non-hydrogenated components were 8-eicosene, 9eicosene, 2-octyldodecene and 9-methyl-8 or 9-methyl-9nonadecene. N-eicosan and 9-methylnonacosan have been identified as components of the hydrogenated dimer.

Among the olefins suitable for use as the starting material in the process of the invention, mention may be made of olefins having 2 to about 20 carbon atoms, such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene and 1-tetradecene and branched chain isomers such as 4-methyl-1-pentene. Various refining feedstocks and streams containing olefins can also be used. Preferably, however, alpha olefins, such as 1-heptene to 1-hexadecene, and preferably 1-octene to 1-tetradecene, or mixtures of these olefins, are used as olefins according to the invention.

The alpha-olefin oligomers of the invention have a low branching ratio (below 0.19) and better lubricating properties compared to the high-branching alpha-olefin oligomers produced by all known industrial processes.

This new class of alpha-olefin oligomers is produced by oligomerization reactions in which a major portion of the alpha-olefin double bonds remain unisomerized. These reactions include oligomerization of alpha-olefins by treatment with supported metal oxide catalysts, such as catalysts containing chromium compounds on silica gel or catalysts containing other compounds of Group VI.B of the IUPAC Periodic Table on a support. Preferred carriers are silica, alumina, titanium dioxide, silica-alumina, magnesium oxide and the like. The metal oxide catalyst is bound to the support material. Preferred are porous substrates whose pores have a diameter of at least 40 x 10 4 / pm.

The carrier material typically has a high specific surface area and a large pore volume, with a mean pore size ranging from 40 to 350 x 10 6 / pm. A high specific surface area is beneficial for the deposition of large amounts of highly dispersed active chromium metal centers and for maximum metal utilization efficiency, resulting in very high catalyst activity. The carrier should have a large mean pore diameter of at least 40 x ΙΟΙΟ / μιη, with pores with a mean pore diameter of> 60 to 300 × ¹⁰ µm being preferred. The large pore diameter pores do not present any diffusion limitation for the reagent and product in terms of access to and removal from the active metal catalyst centers, which is demonstrated by further optimizing catalyst productivity. In order to be able to use this catalyst in a fixed bed or slurry reactor, and to be recycled and regenerated many times, a silica carrier with good mechanical strength is preferred, as this prevents the catalyst particles from being removed or broken during handling or reaction .

practiced on an industrial scale. As found, the metal oxide carrier catalysts are preferably prepared by impregnating the support with metal salts in water or organic solvents. Any suitable organic solvent known in the art, such as ethanol, methanol or acetic acid, may be used. The solid catalyst precursor is then dried and calcined at 200-900 ° C by treatment with air or other oxygen-containing gas. Then, the catalyst is reduced by one of several well known reducing agents such as carbon monoxide, hydrogen, ammonia, hydrogen sulfide, hydrogen sulfide, dimethylsulfide, dimethyl disulfide (CH ₃ SSCH ₃ ), alkyl compounds such as compounds of the general formula

R ₃ Al, R ₃ B, R ₃ Mg, R ₁ and R ₂ Zn, wherein R is alkyl-, alkoxy-, alkoxy-aryl and the like. Carbon monoxide, hydrogen or alkyl metal compounds are preferred.

Alternatively, the Group VI.B metal may be applied to the substrate in a reduced form, such as chromium compounds. The resulting catalyst is a very efficient olefin oligomerization catalyst at a temperature ranging from room temperature to 250 ° C, preferably from 90 to 250 ° C, and most preferably from 100 to 180 ° C at a pressure of 10.1 to 34,500 kPa . The contact time between the olefin and the catalyst may vary from 1 second to 24 hours. The mass hourly space velocity (WHSV) is 0.1 to 10 h ^-1 based on the total catalyst load. The catalyst may be used in a batch-type reactor or in a continuous flow fixed bed reactor.

Typically, the carrier can be added to a solution of metal compounds, for example, acetates or nitrates, etc. and the mixture is then stirred and dried at room temperature. The dry solid gel is blown at a gradually increasing temperature up to 600 ° C for 16-20 hours. The catalyst is then cooled under an inert atmosphere to a temperature of 250 to 450 ° C and contacted with a stream of a pure reducing agent, such as carbon monoxide, until a sufficient amount of carbon monoxide has passed through the catalyst to reduce the catalyst, indicated by a marked color change. from bright orange to pale blue. Typically, the catalyst is treated with approximately twice the stoichiometric amount of carbon monoxide to reduce the catalyst to a lower valence state, i. j. to chromium compounds. Finally, the catalyst is cooled to room temperature and ready for further use.

The oligomers obtained as a product have a very wide viscosity range and high viscosity index values suitable for demanding lubrication applications. Oligomeric products have an atactic molecular structure and contain predominantly units attached in a head-to-tail configuration, and this uniform structure is only disrupted by a smaller number of units attached in a head-to-head configuration. These low branching oligomers have high viscosity index values that are at least 15 to 20 units and usually 30 to 40 units higher than the viscosity index values of known oligomers of the same viscosity. These oligomers are known to have a higher branching ratio and a corresponding lower viscosity index. Low branching oligomers have better or comparable flow temperatures.

The branching ratio, which is defined as the ratio of methyl groups to methylene groups in the lubricating oil, is calculated from the mass fraction of methyl groups detected by infrared analysis according to the methods described in Analytical Chemistry, Vol. 25, no. 10, p. 1,466 (1953).

mass fraction of methyl groups branching ratio = ----------------------- ^L -

- (mass fraction of methyl groups)

As previously described, support catalysts containing chromium oxide in various oxidation states are known catalysts for the polymerization of C 3 -C 20 alpha-olefins (DE 3 427 319, HL Krauss and Joumal of Catalysis 88, 424-430, 1984) and a catalyst produced by depositing chromium oxide on silica. The cited publications teach that polymerization takes place at a low temperature, usually below 100 ° C, to form sticky polymers, and that at a higher temperature the catalyst promotes isomerization, cracking and hydrogen transfer reactions. The process of the present invention produces low molecular weight oligomeric products under reaction conditions and using catalysts such that side reactions such as 1-olefin isomerization, cracking, hydrogen transfer, and aromatization are minimized. In order to obtain new low molecular weight products which are suitable as a lubricant base feedstock or as a component suitable for blending with other lubricant feedstocks, the reaction of the present invention is carried out at a temperature higher than 90 ° C to 250 ° C. suitable for the production of high molecular weight polyalpha-olefins. The catalysts used in the process of the present invention do not cause too much range of side reactions, even if they are operated at a high temperature at which low molecular weight fluid oligomers are formed.

The catalysts of the invention minimize all side reactions and oligomerize alpha-olefins to low molecular weight polymers with high efficiency. It is well known in the art that chromium oxides, especially an oxide whose average oxidation state is +3 (chromium), whether pure or supported, catalyzes double bond isomerization, dehydrogenization, cracking, etc. Although difficult to detect the precise nature of the supported chromium oxide, it is believed that the catalyst of the invention is rich in divalent chromium on the support, which more effectively catalyzes the oligomerization of alpha-olefins at high reaction temperatures without causing isomerization, cracking or hydrogenation reactions, etc. However, the prior art catalysts mentioned above may contain a higher amount of trivalent chromium. At low reaction temperatures, alpha-olefins and high molecular weight polymers catalyze the polymerization. However, as mentioned in these references, undesired isomerization, cracking and hydrogenation reactions occur at higher temperatures. On the other hand, high temperatures are required in the manufacture of the lubricant products of the invention. It is also reported in the prior art that chromium-containing support catalysts rich in trivalent chromium or chromium in the higher oxidation state catalyze isomerization of 1-butene with a thousand times higher activity than polymerization of 1-butene. The quality of the catalyst, the process for its preparation, its processing and the reaction conditions have a decisive influence on the efficiency of the catalyst and the composition of the resulting product and distinguishes the present invention from the prior art.

In the preparation of the oligomers by the process according to the invention, very low concentrations of catalysts based on the feedstock are used. Oligomers are formed using 10 to 0.01% by weight catalyst, while the production of high molecular weight polymers uses a 1: 1 catalyst to feed ratio in the above references. Working at a lower concentration of the catalyst of the present invention to produce a lower molecular weight material contradicts conventional polymerization theory as compared to the results cited therein.

The 1-olefin oligomers prepared according to the invention usually have a substantially lower molecular weight than the polymers produced according to the above cited reference, which are semi-solid substances of very high molecular weight. These high polymers are not suitable as a raw material for the production of lubricants, and generally in the synthesis of a product which does not contain detectable amount of dimeric and trimeric components (C _{lo-C 30).} These high molecular weight polymers also have a very low content of unsaturated bonds. In contrast, the products of the present invention are liquid liquids at room temperature which are suitable as a raw material for the production of lubricants. They contain considerable amounts of dimer or trimer and have a high content of unsaturation.

DETAILED DESCRIPTION OF THE INVENTION

The examples are illustrative only and do not limit the scope of the invention in any way.

Example 1

Catalyst example and application procedure

1.9 g of chromium acetate (Cr, (OCOCH ₃ ) ₄ .2H, O (5.58 mmol) (commercially available product) are dissolved in 50 ml of hot acetic acid, and then 50 g of silica gel with 1.70 grain size is added. up to 2.36 mm, a specific surface area of 300 mm ² .g ^-1 and a pore volume of 1 ml.g ^-1 Most of the solution is absorbed in silica gel, and the resulting mixture is stirred at room temperature in a rotary evaporator for half an hour and dried at room temperature. The dry solid (20g) is first purged with nitrogen at 250 ° C in a tube furnace, then the temperature of the tube furnace is raised to 400 ° C in 2 hours and then set to 600 ° C and the substance is purged for 16 hours The catalyst was cooled to 300 ° C under nitrogen, followed by a stream of pure carbon monoxide (99.9%, Matheson) for 1 hour, and finally the catalyst was cooled to room temperature under nitrogen, ready for use. Example 2

The catalyst prepared according to Example 1 (3.2

g) a stainless steel tubular reactor (9.5 mm 3/8 pipe diameter) is filled under a nitrogen blanket in a dry cabinet. The reactor is heated to 150 ° C under a nitrogen atmosphere using a single-zone Lindberg furnace. The pre-purified 1-hexene is pumped into the reactor at a flow rate of 20 ml / h at 965 kPa. The liquid stream leaving the reactor is collected and unreacted starting material and low boiling agent are removed from the reactor at 6.7 kPa. The increased clear colorless liquid has a viscosity and a viscosity index suitable for the lubricant.

sample provisional skin a 1 2 3 operating time (h) 2 3.5 5.5 21.5 mass lubricant yield) 10 41 74 31

kinematic viscosity

(mm ² / s) at 40 ° C 206.5 123.3 104.4 166.2 100 ° c 26.1 17.1 U 5 20.4 viscosity index 159 151 142 143

Example 3

As in Example 2, a fresh sample of catalyst was introduced into the reactor and 1-hexene was pumped into the reactor at 10 mbar at a flow rate of 10 ml.h ^-1 . As shown below, a high viscosity and high viscosity index lubricant is obtained. Experiments have shown that it is possible to obtain a high viscosity lubricant product under various reaction conditions.

pattern A B des operations (h) 20 44 temperature (° C) 100 50 Intermediate yield (w. weight) 8 ,? 8.0 kinematic viscosity (oe ² / s) mp 40 ° C 13170 19011 Mp 100 ° C 620 1048 viscosity index 217 263

Example 4

A commercial chromium-based silica-based catalyst containing 1% chromium on high pore synthetic silica is used. The catalyst was first calcined with air for 16 hours at 800 ° C and then reduced for 1.5 hours with carbon monoxide at 300 ° C. The tube reactor was charged with 3.5 g of catalyst which was heated to 100 ° C under a nitrogen atmosphere. 1-Hexene is pumped through the catalyst at a pressure of 101 kPa at a flow rate of 28 ml.h ^-1 . The products obtained are collected and analyzed.

sample C D E F Operation c (h) 3.5 4.5 6.5 22.5 lubricant yield (Í weight) 73 64 59 21 kinematic viscosity (watch ² / s) at 40 ° C Σ548 2429 3315 9031 100 ° c 102 151 197 437 t index 108 164 174 199

These experiments show that other chromium based catalysts on silica also effectively oligomerize olefins to lubricating products.

Example 5

As in Example 4, the purified 1-decene was pumped through the reactor at a pressure of 20 psi. The product is collected periodically and stripped of fractions boiling below 343 ° C. High-quality lubricants with a high viscosity index are obtained (see the following table).

Reaction temperature (° C) Flotation hourly space velocity ·, ( ^! WSV) (hb Properties of lubricant product kinematic viscosity (mm ² .a '*) at vlskozLtný index 40 ° C 100 ³ C 120 2.5 1,555.4 157.6 217 135 0.6 369.4 53.0 202 150 1.2 266.6 36.2 185 166 0.6 67.7 12.3 181 197 0.5 21.6 5.1 172

Example 6

A similar catalyst is used to test oligomerization of 1-hexene at various temperatures. 1-Hexene is introduced at a pressure of 101 kPa and a flow rate of 28 ml.h ^-1 .

sample G H temperature (° C) 110 200 lubricant yield (® weight) 46 3 viscosity (mm ^ / s) at 40 ° C 3512 3760 Mp 100 ° C 206 47 viscosity index 174 185

Example 7

1.5 g of a catalyst similar to that prepared in Example 4 was added to a two-necked flask under nitrogen. 25 g of 1-hexene are then added. The suspension was heated to 55 ° C under a nitrogen atmosphere for two hours. A little heptane is then added as solvent and the catalyst is filtered off. The solvent and the unrecognized starting material were stripped off to give a viscous liquid in a yield of 61%. This viscous liquid has a kinematic viscosity at 100 ° C of 1,536 mm ^-1 and at 40 ° C of 51,521 mm ^-1 . This example shows that the reaction can be carried out batchwise.

The 1-decene oligomers described below were synthesized by reacting the purified 1-decene with an activated chromium catalyst on silica. The activated catalyst was prepared by calcining chromium acetate (1 or 3% Cr) on silica gel at 500 to 800 ° C for 16 hours, after which the catalyst was treated with carbon monoxide for 1 hour, at 300 to 350 ° C. The 1-decene is mixed with the activated catalyst and heated to the reaction temperature for 16-21 hours. Then, the catalyst is removed and the low-boiling components are distilled off from the viscous product at 200 ° C to 13.3 kPa.

The reaction conditions and results obtained in the synthesis of HV1-PAO are summarized below:

example chrome n · temperature temperature yield ratio crekaleinde oxide ie eprecpva- 1-deced lubricants nifilton (° C) no (° C) Aetely- (w / w) zétor

6 3 700 350 40 90 9 3 700 350 40 90 10 1 500 350 45 66 11 1 600 350 16 92

Examples 8 to 15

Other alpha-olefin oligomers (Examples 8-11) and their branch ratio, kinematic viscosity index at 40 ° C to 100 ° C (V 40 ° C and V 100 ° C) were prepared in similar ways to those described above. and viscosity index are compared to values of the same properties of oligomers prepared by the prior art methods (Examples 12 to 15). The results are shown in Tables 2a3.

Table 2

Values of branching ratio and lubricating properties of alpha-olefin oligomers of the invention

example d · branching ratio CH-U / CHG In 40 ° C (m » ² .. ' ¹ ) At 100 ° 0 (nm ² .. ¹ ) VI 8 0.14 150.5 22.8 181 9 0.15 301.4 40.1 186 10 0.16 1,205.9 128.3 212 11 0.15 5,238.0 483.1 271

Example 16 17 16 kineaetle viscosity (mm ² / ») 18.5 145 <98 viscosity index 16? 214 246 pour point (° C) -> 5 ’C. -40 ° C -32 obssh dlmdru wt ,) O, *! L 0.01 0.02?

Table 3

The branching ratio and lubricating properties of the prior art alpha-olefin oligomers

Example # branching ratio ch ₃ / ch ₂ At 40 ° C (ee / .S ^- !) At 100 ° C ( »2 s l) vr 12 0.24 2b, 9 5.21 136 13 0.19 424.6 41.5 148 14 0.19 1250 100 168 15 0.19 1,247.4 98.8 166

Samples of the oligomers of Examples 12-15 were purchased on the market. They have a larger branching ratio than the samples shown in Table 2. Also, their viscosity index values are lower than the viscosity index values of Table 2.

A comparison of the two groups of lubricants clearly shows that alpha-olefin oligomers, such as 1-decene, with a branching ratio below 0.19, preferably in the range of 0.13 to 0.18, have a higher viscosity index and are better lubricants. The products prepared by the process of the invention have a branching ratio of from 0.14 to 0.16 and provide high quality lubricating oils with a wide viscosity range of 3 to 483.1 mm ² s ^-1 at 100 ° C and a viscosity index of 130 to 280.

Example 16

A commercially available chromium-containing silica catalyst containing 1% Cr on high pore synthetic silica is used. The catalyst was initially calcined with air at 700 ° C for 16 hours and then reduced for 1 to 2 hours with carbon monoxide at 350 ° C. In a suitable reactor, one part by weight of the activated catalyst is added to 200 parts by weight of 1-decene and the mixture is heated to 185 ° C. The 1-decene is fed continuously to the reactor at a rate of 2 to 3.5 parts per minute and 0.5 parts by weight of catalyst are added for each 100 parts by weight of the 1-decene feed. The suspension was stirred for 8 hours to introduce 1200 parts by weight of 1-decene and 6 parts by weight of catalyst. The catalyst is filtered off and the light product boiling at a temperature below 150 ° C at 1 mmHg is collected. The remaining product is hydrogenated using nickel on silica gel as a catalyst at 200 ° C. The resulting product has a kinematic viscosity at 100 ° C of 18.5 mm ² s · s, a viscosity index of 165 and a pour point of -55 ° C.

Example 17

The procedure is similar to that of Example 16 except that the reaction temperature is 125 ° C. The resulting product has a kinematic viscosity at 100 ° C of 145 mm ² s ^-1 , a viscosity index of 214 and a pour point of 40 ° C.

Example 18

The procedure described in Example 16 was repeated except that the reaction temperature was 100 ° C. The resulting product has a kinematic viscosity at 100 ° C of 298 mm · s ^-1 , a viscosity index of 246 and a pour point of -32 ° C.

The lubricating products obtained in Examples 16 to 18 contain the following amounts of dimer and trimer, with the following distribution.

Example 16 distribution of isomers 17 in the dimension 18 (£ w / w) n elkozán 51 28 73 9-netylnonekozán 49 72 27 content of trimmer hm » ) 5.53 0.79 0.27 distribution of isomers v trlnérl (t haot ..) 11-oktyllokozán 55 48 44 9-methyl-l-oktylhene Lkozén 35 49 40 other 10 13 16

These three examples show that the new HVI-PAOs with a wide range of viscosities contain a unique structure and dimer in different proportions.

Molecular weight and molecular weight distribution are analyzed by high pressure liquid chromatography. The equipment used includes a Constametric II high-pressure double piston pump from Milton Roy Co. and the Tracor 945 LC detector. During the analysis, the system pressure is 4.6 mPa and the flow rate of tetrahydrofuran solvent (HPLC grade) is 1 ml.min ¹ . Inject 1 ml of the sample prepared by dissolving 1 g of the PAO sample in 1 ml of tetrahydrofuran as solvent. The sample is eluted through the following columns connected in series (all from Waters Associates: Utrastyragel 10 ⁵ A, P / N 10574, Utrastyragel 10 ⁴ A, P / N 10573, Utrastyragel 10 ³ A, P / N 10572, Utrastyragel 500 A, P / N 10571, molecular weights are calibrated using commercially available PAOs from Mobil Chemical Co., Mobil SHF-61, SHF-81 and SHF-401.

The molecular weight and molecular weight distribution of the products of Examples 16-18 are given in the following table:

Príklsdy 16 17 18 kinematic viscosity prL 100 ° C (nn ² .. “ ¹ ) 18.5 145 298 viscosity index 165 214 246

numerical middle Eolckulo-

Weight U n 1670 2062 5990 weight medium molecular weight H * 2420 4411 13290

molecular weight distributions 1.45 2.14 2.22

Under similar conditions, HVIPAO products can be obtained with low and high viscosities such as 3 and 500 mm ² s ^-1 and a viscosity index in the range of 130 to 280.

Ethylene can be used as the starting material for the conversion to the higher C ₆ and C ₂₀ alpha-olefins by contacting the ethylene with a nickel catalyst at a temperature of 80 to 120 ° C and a pressure of about 1 kPa using industrial synthetic processes described in Chem. Process Evalaution / Research Planning Report-Alpha-Olefins, report no. 82-4. The intermediate product, alpha-olefin, has a wide distribution from C ₆ to C ₂ o · A full range of alpha-olefins obtained by the growth reaction or only parts thereof can be used to produce a high viscosity index lubricant, for example from C ₆ to C ₂₀ . After hydrogenation, the oligomers have a low pour point.

Example 19

The reaction mixture obtained by a growth reaction of alpha-olefin, as described above, having the same molar concentration of _C6-C8-Cio-C | ₂ -C 1 _{The 6} -C ₁₈ -C ₂₀ hydrocarbons are reacted with 2% by weight of activated Cr / SiO ₂ catalyst at 130 ° C and under a nitrogen atmosphere. After 225 minutes of reaction, the catalyst was filtered off and the reaction mixture was distilled to remove the light fraction boiling at below 120 ° C at 13.3 Pa. The residue which constitutes the lubricant is obtained in a yield of 95% and has a kinematic viscosity at 100 ° C of 67.07 mm ² s · s and a viscosity index of 195.

Example 20

The equimolar mixture of the C ₆ to C ₂₀ alpha-olefins described above is continuously fed through an activated Cr / SiO ₂ catalyst placed in a tubular reactor. The results are included below: Table 20

sample Starting And Fabric B C D tiplota <° c) - 123 130 1? 200 overpressure (MPa) - 2.13 2.06 1.72 1.92 weight hour space velocity (h * ^-1 ) - 1.2 1.2 1.2 1.2 dlatribuLa produktu fasten the.) 1-C _fi = 4.7 0.3 O.3 0.3 1.1 1 = -C 12.8 0 3.3 1.1 2.3 1-C, o ' 22.0 1.8 1.8 2.3 4.6 19.4 0.3 0.5 1.4 3.4 1-c = 16.0 0.9 0.9 1.9 4.8 κ «· 11.0 0.6 0.4 1.9 4.3 Κ _1β » 7.7 0.8 1.3 2.7 6.0 ^{1 C} 20 ⁼ 6.5 j 1.8 3.1 6.9 ^C 50 ^{O 3 C 3 O} 0 4.4 2.6 7.8 18.7 aezedlo 0 90.5 90.1 78.3 47.5 properties of the gap kinematic viscosity at 100 ° C (nm ² .e ¹ ) - 75.11 51.24 12.12 14.84 viscosity index - 190 184 168 164

Example 21

Equimolar mixture of C ₆ -C ₈ -C ₁₀ -C ₆ olefins _{The 2} -C 14 is reacted on a similar Cr / SiO ₂ catalyst as in Example 2. The results are shown in Table 21. Table 21

pattern starting the substance A they C D temperature 1 ° C) - 120 150 190 234 overpressure (MPe) - 1.72 1.44 1.37 1.37 weight per hour spatial velocity Product distribution (including mass) (h ^-1 ) - 2.5 2.5 2.5 2.5 1-C ₆ ' 16.3 0.3 0.6 1.2 6.9 Ke ^- 25.0 0.5 1.1 1.8 4.3 '4 26.3 5.6 2.9 2.7 10.9 1-C1 ₂ - 19.9 0.5 0.9 1.5 9.1 1-C _U - 12.4 0.0 1.1 3.2 7.4 ⁰ 20 · ° 3Ο 0 0.0 5.1 23.8 19.7 mezodio ABOUT 93.0 es, 4 65.8 42.7 Vlestnoetl mezedla kinematic viscosity at 100 ° C (aa ² .e ^_1 ) - 101.99 46.31 17.97 7.31 viscosity index - 107 165 168 157 flow point after hydro- -33 -43 -70 -41 GENISATION (C)

A mixture of alpha-olefins from ethylene growth reactions and double decomposition can be used to produce high quality lubricants by the process of the present invention. This makes the process cheaper since these feedstocks are more accessible than individual monomers.

Example 22

The standard procedure for the oligomerization synthesis of 1-decene at 125 ° C is repeated using other Group VI.B metals, namely tungsten or molybdenum. The porous substrate modified with tungsten or molybdenum is reduced with carbon monoxide at 460 ° C. The metal content of the reduced oxide is 1% by weight. The molybdenum catalyst provides a 1% yield of a viscous liquid. The tungsten catalyst is provided as C ₂ of the dimer.

The use of Group VI.B metal support oxides as a catalyst for olefin oligomerization to form lubricating products with low branching ratio and low flow point has hitherto been unknown. The catalytic process for the production of oligomers having a structure having a low branching ratio that does not use a corrosive catalyst and produces a lubricant with a wide viscosity range and a good viscosity index has hitherto been unknown and likewise a process for preparing lubricating oils with a branching ratio lower than 19th

While the invention is described in preferred embodiments, it will be apparent to those skilled in the art that it may be varied and modified in various ways. To the extent that these modifications and variations are within the spirit of the invention, they are intended to be included within the scope of the invention, which is limited only by the following definition of the invention.

Claims (14)

PATENT CLAIMS Liquid lubricating composition, characterized in that it consists of alkanes or alkenes of 30 to 1,300 carbon atoms with a branching ratio of less than 0.19, a weight average molecular weight of 300 to 45,000, a number average molecular weight of 300 to 18,000 a molecular weight distribution of 1 to 5, a pour point below 15 ° C, a viscosity index above 130 and a kinematic viscosity at 100 ° C of 3 to 750 mm ² s -1. 2. A liquid lubricating composition according to claim 1, which comprises alkanes or alkenes of 30 to 1000 carbon atoms with a molecular weight distribution of 2.5. 3. A liquid lubricating composition according to claim 1, comprising a C ₃₀ fraction having a branching ratio below 0.19, having a viscosity index greater than 130, and having a pour point below 45 ° C. 4. A liquid lubricating composition according to claim 1, wherein the hydrogenated polymers contain a residue of linear 1-alkenes containing 6 to 20, preferably 8 to 12, carbon atoms. 5. The liquid lubricating composition of claim 4, wherein the polymeric residue is poly 1-decene, having a molecular weight of 422, a viscosity index of 134, and a pour point below 45 ° C. 6. A liquid lubricating hydrocarbon composition according to any one of claims 1 to 5 comprising a polymer product having repeating units of the general formula: 4 ^ch 2 - 4 Where n represents a number from 3 to 17 and x represents a number from 5 to 500. 7. The liquid lubricating composition of claim 6, wherein n has a value of 7 and the mean value of x is at least 15. 8. The liquid lubricant composition of claims 1 to 7, characterized in that it comprises a mixture of alkanes ₀ C, consisting of 9-methyl-l-oktylheneikozánu a 11-oktyldokozánu in a molar ratio of 1: 10-10: 1, preferably from 1: 2 to 2: 1. 9. A liquid lubricating composition according to any one of claims 1 to 7, wherein the composition comprises C 10 H 8 alkanes with a branching ratio below 0.19, a kinematic viscosity of 3 to 4 mm ² · s ^-1 at 100 ° C, a viscosity index above 130 and a pour point. below -15 ° C, preferably below -45 ° C. Liquid lubricating composition according to 1 to 9, characterized in that it contains 11-octyldocosan of the formula 11. A process for the production of a liquid lubricating composition according to any one of items 1 to 10 from alpha-olefins or mixtures thereof, characterized in that olefins of 6 to 20 carbon atoms are oligomerized at a reaction temperature of 90 to 250 ° C in contact with the catalyst at a weight ratio of alpha-olefins to catalyst of 10: 1 to 30: 1, wherein the catalyst comprises chromium in a lower valence state than the highest valence state and is deposited on a porous support, and wherein the catalyst is prepared by oxidation at 200 to 900 ° C in the presence gas and then reduction with a reducing agent, e.g. carbon monoxide. 12. The process of claim 11, wherein the oligomerization is carried out at a temperature of 100-180 ° C. 13. The method of clause 11 and 12, characterized in that the porous carrier is silica having pore size of at least 40.1 θ ^"4 pm. 14. Process according to Claims 11 to 3, characterized in that alpha-olefins having 8 to 14 carbon atoms are used, preferably 1-octene, 1-decene, 1-dodecene, 1-tetradecene or mixtures thereof.