CA1219289A - Manufacture of synthetic lubricant additives from internal olefins using boron trifluoride catalysis - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
An improved process for the manufacture of synthetic lubricant additives from internal olefins is described. The process utilizes boron trifluoride catalysis with a promoter to produce oligomer mixtures that have surprisingly low viscosities at low temperatures and surprisingly high viscosity indexes as compared with the oligomers found in other methods.
It is important that internal olefins be used almost exclusively in the method of this invention.

Description

BACKGROUND OF THE INVENTION
1. Field of the Invention The invention relates to processes for the pro-ductior. of oligomers from olefins, and more particularly re-lates to the production of oligomers from internal olefinsby means of a boron trifluoride catalyst.

2. Description of Related Methods Friedel-Crafts catalysts have long been known to oligomerize olefins. For example, see U. S. Patent 3,410,925 to Eby, et al. in which olefins are mixed with alkylatable aromatic hydrocarbons over a Friedel-Crafts catalyst to form an alkylation sludge which is then mixed with olefins having

3 to '8 carbon atoms which are also passed over the catalyst to produce olefin dimers. U. S. Patent 3,652,706 to Saines, et al. describes the polymerization of olefins having 2 to 20 carbon atoms over a Friedel-Crafts metal halide catalyst plus a hydrogen form of mordenite to produce compounds hav-ing a molecular weight between 700 and 2,500. Production of a gasoline fuel composition is described in U. S. Patent 3,749,560 to Perilstein which occurs by reacting a mixture of mono olefins (greater than 50 weight per cent alpha ole-fins~ over a Friedel-Crafts catalyst heated to a temperature around 145~C to produce oligomers having molecular weights between 350 to l,500. Also, U. S. Patent 3,149,178 to Hamilton, et al. reveals an improved method for making polymerized olefin synthetic lubricants via a particular distillation techni~ue of oligomers made from alpha mono olefins using a Friedel-Crafts catalyst. Alpha olefins hav-ing six to twelve carbon atoms may be dimerized in the pre-- 30 sence of a Friedel-Crafts catalyst according to the method described in U. S. Patent 4,172,855 to Shubkin, et al.
It is also known that the term "Friedel-Crafts cat alysts" includes boron trifluoride among other metal halide-type Lewis catalysts, see Kirk-Othmer Encyclopedia of Chemical Technology, Third Edition, Vol. 11, pg 292. Boron trifluoride has also been known to polymexize olefins, as seen in F. Albert Cotton, et al., Advanced Inorqanic Chemistry: ~ Comprehensive Text, Interscience Publishers, 1962, p. 191.
A number of U. S. patents have also used BF3 to oligomerize olefins. Close study will revea~ that alpha ole-fins are considered the only useful form. For example, U. S.
Patent 2,780,664 to Serniuk describes the reaction of conju-gated dienes with mono alpha and internal olefins over BF3 promoted by an ether mixed with a halo aIkane diluent at a temperature from -30 to 100C to produce oligomers suitable for drying oils. Alpha olefins having from 5 to 20 carbon atoms are oligomeri~ed using BF3 plus an alcohol or water promoter as described in U. S. Patent 3,382,291 to Brennan.
In this patent, BF3 and a mixture of BF3 plus the promoter complex are introduced in two separate streams. Another U. S.
patent by Brennan, 3,742,082, concerns the dimerization of alpha olefins via BF3 which is promoted with phosphoric acid or water at a temperature from 100 to 150C. U. S. Patent 3,763,244 to Shubkin, which describes the oligomerization of n-alpha olefins having 6 to 16 carbon atoms over BF3 pro-moted with water, at a temperature between 10 and 60C where it is preferred that BF3 is added continuously.
Yet another U. S. patent to Brennan, 3,769,363, describes the oligomerization of olefins having 6 to 12 car-bon atoms using BF~ with a carboxylic acid promoter having at least 3 carbon atoms at a temperature between 0 and20C to produce olefins heavy in trimer form. U. S.
Patent 3,780,128 also to Shubkin relates to the oligomer-ization of alpha olefins having 6 to 16 carbon atoms in which BF3 is employed in a molar excess of alcohol. U. S.
Patent 3,876,720 to Heilman, et al. describes a two-step procedure by which alpha olefins having 8 to 12 carbon atoms are converted to vinylidene olefins which are then reacted over a 1:1 molar complex of BF3 and alcohol to produce oligomerized vinylidene olefins. A method for oligomerizing both short and long chain alpha olefins having from 14 to 20 carbon atoms simultaneously over BF3 with an alcohol or water promoter at 0 to 60C with a monomer recycle is des-cribed in U. S. Patent 4,225,739 to Nipe, et al. There is also U. S. Patent 4,263,465 to Sheng, et al. which describes a two-step process for reacting one-butene with a higher alpha olefin over BF3 in the pres~nce of a proton donor at a temperature from -30 to 50C to produce an oligomer having 8 to 18 carbon atoms. The intermediate oligomer i~ reacted with other higher alpha mono olefins over the same catalyst system from -30 to 60~C to produce oligomers having 20 to 40 carbon atoms. For more information on BF3-catalyzed olig-omerization of alpha olefins, see Brennan, "Wide-Temperature Range Synthetic Hydrocarbon Fluids," Ind. Eng. Chem. Prod.
Res. Dev. 19~0, Vol. l9, pp 2-6 and Shubkin, et al., "Olefin Oligomer Synthetic Lubricants: Structure and Mechanism of Formation," Ind. Eng. Chem. Prod. Res~ Dev. 1980, Vol. 19, pp 15-19.
Two patents have been located which involve the reaction of internal olefins over Friedel-Crafts cat-alysts. U. S. Patent 4,167,S34 to Petrillo, et al. des-cribes olefins which are both alpha and internal having from 10 to 15 carbon atoms which are reacted over Friedel-Crafts catalysts between 20 and 200~C to produce oligomers. The catalysts used in the examples of this patent are only AlCl3 and NaAlCl~. The internal olefins are also those that are statis-tically distributed. Also, the oligomers found useful therein seem to be the hydxogenated bottoms product after the unreacted olefins are removed, without further dis-tillation. U. S. Patent 4,218,330 to ~hubkin describes hydrogenated dimers from alpha olefins having from 12 to 18 carbon atoms, especially 1-tetradecene, made u~ing a Friedel-Crafts catalys-t, which includes therein boron trifluoride with a promoter. Shubkin's method uses predominantly alpha olefins, although the specification mentions that "fairly large amounts of internal olefins can be tolerated ~ithout adversely affecting the physical properties o~ the oligomer."
This last remark from Shubkin reveals the general feeling of those working in the field that internal olefins do not pro-duce oligomers with good properties for synthetic lu~ricants.For example, in U. S. Patent 3,952,071 to Isa, et al., it is revealed that olefins may be oligomerized in the presence of a mixture of a polyhydric alcohol derivative and an aluminum halide. Isa, et al. mention that the olefin could be internal or alpha although alpha olefins are -the only ones used in the examples therein. U. S. Patent 3,947,509, also to Isa, et al., also claims that internal olefins may be used over a ketone and ester ether or alcohol promoted aluminum chloride catalyst although only alpha olefins are used in the ex-amples.

U. S. Patent 4,300,006 was issued on November 10,1981. It describes a process for producing a hydrocarbon oil by contacting a mixture of alpha and at least 50 weight per cent internal olefins with, a boron trifluoride dimeri-zation catalyst. However, the productivity of useful pro-ducts from the process revealed in U. S. Patent 4,300,006 is ~lite low. For example, an alkane diluent is found to be necessary in the process described therein which, in addition to distilling out the lights and the heavies to obtain the lube oil, results in little useful product. Fur-ther, this method requires a much longer reaction time and a higher catalyst concentration than desired. It would be beneficial if a method or producing synthetic lubricant com-ponents could be devised which would overcome the afore-mentioned disadvantages.
In the field of oligomerizing olefins for syntheticlubricants, it is a continual problem to produce olefins hav-ing low viscosities at room temperature and below but which have a high viscosity index and low volatility.

SUMMARY OF THE INVENTION
The invention relates to a process for oligomeriz-ing mono olefins comprising contacting a mixture of olefins having between 9 and 24 carbon atoms, inclusive, and having '' A 99 weight per cent or more of internal olefins with a cat-pre~e,rab/~-alyst comprising boron trifluoride)~together with a promoterat a reaction temperature sufficient to effect oligomeri-zation of said olefins.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
It has been surprisingly discovered that oligomers which have an unusual blend of properties may be made by re-acting predominantly internal mono olefins with boron tri-fluoride and a promoter. It must be stressed that this dis-covery has not been found by any of the other researchers in the field. It is also important to note that predominantly internal olefins are employed in the method of this in-vention.
Generally, the olefins should have between 9 and 24 carbon atoms, inclusive. The internal olefins used here-in have the double bond randomly distributed across the molecule. In this context, the term "randomly distributed"
means that the double bond in the internal olefin is not predominantly in any one location. For example, an olefin mixture being comprised of a majority of alpha olefins would be outside the scope of this definition since the double bond would be located predominantly between the first and second carbon atoms of the molecules. Likewise, since the internal olefins used for oligomerization in the method of U. S. Patent 4,300,006 are made by disproportionation of alpha olefins, the double bond is located predo.minantly at or near the center of the molecule, and such olefin feed-stocks also fall outside the definition of having a "random distribution" of the double bond. A random distribution in-cludes the distribution one may obtain upon the dehydro~
genation of paraffins. One would expect a small amount of alpha olefin to result from such a distribution. However, one would also anticipate that the alpha olefin proportion would be only about 0.1 weight per cent, with a maximum value belng about 1.0 weight per cent. As a practical matter, the feedstocks herein can be considered to be - 30 entirely internal olefins.

The internal olefins may ~e generally expressed as compounds having the formula RCH=C~R' where R and R' are the same or different alkyl radicals of one to twenty one carbon atoms. However, the total number of carbon atoms sho~ld not exceed about twenty four and should not be less than nine.
The internal olefin mixtures are potentlally more available than the pure cut alpha olefins and are potentially as cheap or cheaper than the corresponding pure cut alphas. It will be shown that the method of this invention affords higher quality products and higher conversions than those obtained with AlCl3 and AlCl~Na catalysts.
By careful selection of the molecular weight of the feed olefins and the reaction conditions, it was found that a synthetic lubricant base oil with a specific ~is-cosity can be made by the method of this invention which hassuperior proper-ties o~er those made by other methods. For example, it has been found that a base oil having a 210F
viscosity of about 4 centistokes with excellent properties can be made with internal olefins having 13 or 14 carbon atoms. A l'four centistoke fluid" is a designation given to fluids used in lubricating oil compositions which generally have 210E' viscosities of about 4 centistokes.
The catalyst of choice is boron trifluoride. A
number of different kinds of promoters may be used, such as alcohols, carboxylic acids or water. It is especially pre-ferred that 1 butanol be used as the promoter. The temper-ature range at which the oligomerization may be performed successfully is between 25 and 150C, with an especially preferred range between 65 to 105C. The pressure range of - 30 the reaction may run from atmospheric to 1000 psig. The oligomerization of the olefins may be conducted in a batch or continuous mode. First, the experimental methods will be described, and then the results will be tabulated.
COMPARATIVE EXAMPLES
A number of comparative oligomerization examples were run using the procedures of U. S. Patent 4,167,534. It is believed that this patent constitutes the closest prior art.
The examples herein were patterned after Examples 1, 5 and 7 therein. These examples were chosen because they represented a wide variety of conditions, particularly temperature. The primary variable in the comparative examples is the olefin feed material, although sometimes twice the amount of AlC13 used in the 4,167,534 patent is employed in an attempt to improve the conversion.
Accorcling to the disclosure in U. S. Patent 4,167,534, Example 1 is begun by heating the feedstock to 80C. The feedstock is then added over 15 minutes with 1% AlC13. The temperature is then raised to 100C and maintained for 100 minutes. The product is then discharged, separated from the heavy catalytic layer, washed with caustic solution and then distilled.
Example 5 begins by adding the olefin feed at room temperature with 1% AlC13 in only one portion. The temperature is allowed to rise on its own for 120 minutes. The product is then discharged, separated from the heavy catalytic layer, washed with caustic solution and distilled.
The feed in Example 7 of U. S. Patent 4,167,534 is added at 13~C with 5% NaAlC14 over 90 minutes. The reaction mass is then maintained at 130C Eor 60 minutes further. The product is then discharged, separated from the heavy catalytic layer, washed with caus-tic solution and dis-tilled. The results of the comparative examples are shown in Table I.

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With respect to the results outlined in Table I, the conversion is a weight per cent of monomer oligomeIized as determined by liquid chromatography. The weight per cent of the bottoms as based on the olefin charged is given in the next column. While these two columns of data generally measure the same concept (notice the qualitative correlation), the applicants prefer to use "% conversion" while the in-ventors in U. S. Patent 4,167,534 used the "% bottoms" method.
Both are employed in the examples of Table I for comparative purposes.
Kinematic viscosities at two standard temperatures are given in centistokes. The viscosity index (VI) is the change in viscosity with temperature such that the higher the number, the lower is the change in viscosity with temp-erature. Conversely, a low VI signifies a large change inviscosity with temperature. Pour point is a measure of the lowest temperature, in degrees Fahrenheit, at which the sample will begin to pour. Below that temperature the composition may generally be regarded as a solid. The thermogravimetric analysis (TGA~ is a measure of volatility via measuring the weight per cent of sample remaining at 233C as the temperature is raised in a slow, uniform manner, usually 10C per minute. An oligomer product should have a TGA analysis with at least 80% of the sample remaining at 233C in order to have sufficiently low volatility to be use-ful as a base stock for lube oil formulation.
EXAMPLES ILLUSTRATING THE INVENTION
The following examples illustrate the method of the invention using BF3 as the catalyst and only internal - 30 olefins as the olefin feed. Two examples are included using.

Cl4 alpha olefin as the feedstock to show that an unsuitable oligomer mixture is produced. The oligomer from alpha ole-fins having 14 carbon atoms (l-tetradecene) was deficient in its low temperature properties for use in crankcase engine oils. Generally, the viscosity at 25C should be 30 to 30.5 centistokes ~cs) or less while the C14 alpha olefin oligomer was observed to be in the 32-33 cs range. The pour point of a synthetic lubricant base oil candidate should be less than -50F. These differences are exaggerated at -30C (the temp-erature at which cold cranking viscosity tests are done) and would result in a too viscous fluid at cold temperatures.
Preferably, a "4 centistoke fluid" (measured at 210F) should have a viscosity between 25 and 40 centistokes at 25C, a viscosity between 3.5 and 5.0 centistokes at 210F, a viscosity index of greater than 100, a pour point of less than -50F and a thermoyravimetric analysis per cent remain-ing at 233C value of greater than 80 weight per cent. It is especially preferred that 4 centisto~e fluids have a viscosity of between 25 and 34 centistokes at 25C, a vis-cosity between 3.5 and ~.5 cs at 210F, a minimum viscosity index of 110, a maximum pour point of less than -50F and a thermogravimetric analysis (TGA) value of 86%, minimum.

A solution of 43.8g C13 14 15 random internal lin~
ear olefins (53.4% C13, 45.0% C14, 0.5% C15, 1.1% paraffi~s) and 0.12g l~butanol in a nitrogen atmosphere was saturated with BF3 at 25C by slow sparging for 25 minutes. Pot con-tents were maintained at 25-27C by external cooling while 55 6g of a solution of 55.0g C13_14_15 1-butanol was added over 1 2/3 hours. ~oron trifluoride saturation was maintained during this addition and for 1-3/4 hours thexeafter. Boron trifluoride introduction was stopped and the pot contents were heated to 86C over a 1-3/4 hour period, and maintained at 85-86~C for 1/2 hour. After cool ing, 110 ml H20 was added; the contents were stirred rapidly for 20 minutes, and the top layer was removed. It was washed with 115 ml H20 and stripped on a rotary evaporator at 30 mm Hg to a maximum bath temperature of 95C; 96.9g of a clear light yellow liquid remained (98.3% recovery). Analysis by gel permeation chromatography indicated 61.34% dimer, 25.13%
trimer, and 12.95% monomer, the bala~ce being higher olig-omers.

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The product of Example 12 (93.8g) was hydrogenated over 9.60g of a powdered Wi/Cu/Cr catalyst, which is described in U. S. Patent 3,152,99B. The conditions included a pressure of 1800 psig H2 and a temperature of predominantly 208C (with temperature briefly reaching 316C).
Vacuum stripping was conducted at 0.9 mm Hg, with a maximum head temperature of 105C and a maximum pot temperature of 157C, to remove 11.89g of lighter components (~91% monomers).
The hydrogenated bottoms product consisted (GPC analysis) of 26.7% trimer, >67.8% dimer, and >3.41% monomer. The kinematic viscosities at 25C, 100F, and 210F were 29.57, 18.26 and 3.89 centistokes, respectively. The pour point was measured to be less than -50F. Thermogravimetric analysis indicated 81.3% of the sample remained at 233C.

~ -14-5t9 This is essentially the same procedure as Example 12 except BF3 introduction was stopped when olefin/ l-butanol introduction stopped. The heating period was for 2 hours at 90C. GPC analysis indicated 19.8% trimer, 62.2~ dimer and 17.94% monomer, the balance being higher oligomers.
Hydrogenation In order to form materials which have adequate oxida-tive stability for lubricants, the oligomerized olefins are optionally hydrogenated either partially or totally. This hydrogenation is done by procedures known to those skilled in the art as exemplified by U. S. Patents 4,045,508; 4,013,736;
3,997,622 and 3,997,621. A particularly preferred catalyst for this hydrogenation is a nickel-copper-chromia catalyst described in U. S. Patent 3,152,998. As is well known, such hydrogenations may be perEormed in either batch or continuous modes.
When the instant inventive method was scaled up for a pilot plant run, it was discovered that the resulting oligomer mixture did not give the expected desirable properties seen in the lab scale experiments. In the pilot plant scale-up, strip-ping out the monomer was performed first and then hydrogenation was conduc-ted over the nickel-copper-chromia catalyst described above. Monomer removal was performed before hydrogenation and recycled to the oligomerization step. However, during the pilot plant stripping step over 50% of the oligomer material came off overhead at temperatures starting at about 210C to about 282C at the finish in an attempt to obtain a material with a good TGA (vola-tility) value. ~pparently, some of the unhydrogenated oligomer mixture was thermally unstable -- ~. ., 3 :\ f " i/

and portions of it were reverting to monomers or intermedia-tes and distilling off as volatiles. It is, therefore, importan-t that monomer removal be accomplished at as mild conditions as possible; that is~ the reboiler or pot temperatures should preferably be kept at or under 180C, preferably from 150C
to 180C or 160C to 180C, when stripping out monomer.
While the methods of others in the field include a distillation step after hydrogenation procedure to obtain pro-ducts of various 210F viscosities, i-t is much preferred in the method of the invention that no fur-ther distilla-tion be conducted. In other words, the monomer-stripped, hydrogenated bottoms are the desired synthetic lubricant components. Thus the method of this invention does not require the customary distillation step, yet surprisingly produces a synthetic lubricant component that has excellent properties and performs in a superior fashion. ~Iowever, it is also anticipated that one skilled in the art may find subsequent distillation useful in the practice of the method of this invention.

~16-The following examples illustrating the method of the invention were conducted according to one of the follow-ing procedures.
Procedure A
Examples 15 through 18 used the following experi-mental procedure. To a 390 ml stainless steel clave (316 SS) was charged 158.6g of olefin and 1.4g of 1-butanol. The clave was sealed and hea-ted to approximately 98C at which time BF3 gas was introduced in amounts ranging from 3.1 to 4.4g (average 3.8g BF3 per run). The reaction was stirred and allowed to exotherm on its own (no cooling). The re-action was stirred for 60 minutes (time measured from first BF3 addition and BF3 added over a 3-6 minute period) and then cooling water turned on. The cool reaction mixture was neutralized with 10 grams of Na2C03 and 100 ml H20. After layer separation, the organic layer was washed twice more with fresh water and dried. The oligomer was analyzed (GPC/LC) for conversion and subjected to hydrogenation at 210C (2 hours), 2,000 psig H2 pressure in the presence of a nickel-copper-chromium oxide catalyst (5% by weight basis weight oligomer). Stripping the oligomers of monomer was performed after hydrogenation in all of Examples 15-26 in a manner similar to that of Example 27.

Procedure B
Examples 19 through 23 used procedure B which was identical to Procedure A except that 0.7g butanol was used (instead of 1.4g) and the amount of BF3 added ranged from 2.2 to 2.8g with a 2.5g average.

Procedure C
Examples 24 through 26 used Procedure C which was identical to Procedure A except that the temperature of the reaction mixture (olefin and promoter) before BF3 addition was 65C (instead of 98C~ and the amount of BF3 added ranged from 2.2g to 4.0g (3.0g average). Conversions and properties of the oligomers are summarized in Table II.
It sho~ld be noted that the amount of catalyst used in the method of this invention (1.4 to 2.8 weight per cent of the olefin feed) is notably less than the amount of catalyst used in other methods in the field, such as the method disclosed in U. S. Patent 4,300,006 (2.6 to 6.1 weight per cent). In further contrast with the method of this particular patent, no employment of a diluent, no heavies or lights (except monomers) removed, and a shorter reaction time are features of the inventive method. Another difference lies in the fact that the method of U. S. Patent 4,300,006 uses a mixture of alpha and internal olefins hav~
ing carbon numbers that are ~uite different from each other, unlike the instant method.

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It may be noted from inspection of Tables I and II
that alpha olefins produce invariably poorer oligomer mix-tures than do internal olefins. No examples have higher vis-cosities at both 210~F and 25~C than do the alpha olefin Ex-amples 4, 8 and 11. It must be remembered that the inventivemethod herein has the requirement of using only int~rnal ole-fins to obtain low viscosities, a feature not found in any related method. It should also be pointed out that oligomers made from alpha olefins (Examples 4, 8, 11, 23 and 26) have rather high pour points, which make them unacceptable for use in synthetic lubricants. The high pour point of Example 19 is thought to be an erroneous data point.
Secondly, it may be noted that the viscosities of the BF3 catalyzed oligomers are all lower than those pro duced by the method of U. S. Patent 4,167,534. In addition, the conversions are much higher in the BF3 runs~ It is par-ticularly surprising that C13 14 internal olefins (Examples 15, 19 and 24), having a higher average molecular weight than the C11 14 internal olefins (Examples 16-18, 20-22 and 25) produce olefin mixtures having a lower viscosity than the mixtures from C11 14 internals. These examples show how the choice of molecular weight range of the olefin feedstock greatly affects the properties o the product oligomers.
It is surprising that such low viscosities (relative to other methods) may be found in oligomer mixtures that also have low pour points and viscosity indexes and volatilities comparable with those of other methods. It is precisely such a blend of advantageous properties that is being sought after in the field and which has not been discovered until now.

In addition, it should be noted that the method revealed in U. S. Patent 4,300,006, re ~ res that the dimeriza-tion feedstock be obtained from the dispropor-tionation of alpha olefins having 8 to 10 carbon atoms. As a result, the dimerization feedstocks therein are a mixture of alpha and internal olefins where the alpha olefins have slightly more than half the carbon number of the corresponding internal olefin and the internal olefins are highly symmetrical (being formed from the disproportionation of two alpha olefins). For example, Runs IX and XII therein oligomerize C14, C16 and C18 internal olefins where the double bond is at or near the center of the olefin molecule. The inventive method uses instead internal olefins where the double bond is randomly distributed instead of located near the center of a symmetrical mono olefin.
These differences in the feedstocks cause impc,rtant differences in the properties in the resulting oligomers, as shown by the following examples involving C14 internal olefin and C8 alpha olefin as a mixed feedstock.

Oligomerization The oligomerization of a 70 weight per cent C14 internal olefin and 30 weigh-t per cent C8 alpha olefin mixture was accomplished over 2.5g of a boron trifluoride catalyst with l.lg of 1-butanol as a protonic promoter and initiated at 95.1C.
To a dry and clean 300 ml Hastelloy C autoclave were added ll9g of C14 internal olefin from Shell Chemical Company's Higher Olefin Process (SHOP). The double bond in these internal olefins is randomly diskributed throughout ~ 21-the molecule. Added at the same time were 51g of C8 alpha (l-octene from Aldrich Chemical Company, Inc.). At the time, this was the closest approximation possible of the U. S. Patent 4,300,006 feedstock. These additions were followed by l.lg of l-butanol promoter. The clave was sealed and the contents heated to 95.1C with stirring.
Starting at 95.1C, BF3 gas was introduced by adding four shots of BF3 over an 11 minute period (2.5g total BF3 added) to the stirred reaction mixture. At the end of 17 minutes (measured from the first BF3 addition), the temp-erature had risen 110.2C fox a maximum exotherm of 15.1C.
One hour after the first BF3 addition the reaction temper-ature was 101.5C. The heat was turned off and cooling water turned on. The reaction mixture was neutralized with an aqueous Na2C03 solution and water washed twice more. The organic layer was separated and dried by filtering through folded filter paper to obtain a net weight of 156.3g.
Liquid chromatography analysis indicated 31.9% o~f the material was C8, C14 or C16 and 27.5% was dimer C22 (from C8 and C14) and 32-2% was dimer C28 (from C14 and C14) while 8.4% was C36 or heavier. Conversion to material higher than C16 was about 68.1%. The ratio of dimer to trimer and heavies was 7.19:1.
~ydrogenation and Strip~in~

A l-liter stirred 316 stainless steel clave was charged with 144.5g of oligomer from the previous step and 7.2g of a nickel-copper-chromium oxide hydrogenation cat-alyst. The clave was flushed with hydrogen three or four times and pressured to 1,000 psig with hydrogen. Subse-quently,-the clave was heated to 210C (the pressure in-creased to only 1,200 psig) and pressurized again to 2,000 psig with hydrogen. The reaction mixture was stirred at 210C for four hours during which the pressure remained at 2,000 psig. The hydrogenated oligomer was filtered and 137.3g subjected to high vacuum stripping. The ma-terial was distilled through a jacketed column (with about 12 in. of Goodloe packing) until the head temperature reached 105C at 0.06 mm Hg. The bottoms weighed 67.lg (49.6% of the total material, overhead plus bottoms) and the overhead weighed 68.3g (50.4% of the total material). The bottoms product had a 210F viscosity of 3.6 cs, a 25C viscosi-ty of 27.4 cs, a pour point of <-50F and a viscosity index of llO.
Liquid chromatography analysis indicated the presence of 25.5% dimer (C22), 60.2% dimer (C28) and 14.3% heavier materials. The TGA of the bottoms product indicated volatility was moderately high (85.0% sample remained at 233C in TGA of 10C/minute).

Oligomerizatlon Oligomerization of a 70% Cl4 internal olefin - 30%
C8 alpha olefin mixture catalyzed by 2.2g of BF3 with l.lg of l-butanol as a promoter was initiated at 94.9C. As in the previous example, ll9g of Cl4 internal olefin were added to a 300 ml clave along with 51g of C8 alpha olefin followed by l.lg of 1-butanol. The clave was ~ealed and heated to 94.9C. Starting at 94.9C, BF3 gas was added over an 11 minute period (totalling 2.2g of BF3) to produce a 15.1C
maximum exotherm af-ter 16 minutes had elapsed after the first BF3 addition. After a one hour reaction time measured -~3-from the first BF3 addition, the mixture was cooled and neutralized with aqueous sodium carbonate. The organic layer was separated and dried by filtering through folded filter paper, to give a net weight of 162.5g. Liquid chromatography analysis indicated 31.1% of the material was C8, C14 or C16 27.2% was dimer C22 and 33.4% was dimer C28 while 8.3% was C36 or heavier. Conversion to materials higher than C16 was 68.9%. The ratio of dimer to trimer and heavies was 7.3Q:1.

Hydrogenation and Stripping From the above step, 145.0g of the oligomer was hydrogenated over 7.2g of nickel-copper-chromium oxide cat-alyst. The hydrogenation was conducted at 210C and 2,000 psig from hydrogen for four hours. It was followed by fil-tration and stripping as described in the previous example.The bottoms products amounting to 55.3% of the charge had a 25C viscosity of 25.7 cs and a 210F viscosity of 3.45 cs.
The pour point of the bottoms material was unacceptably high, -40F, and the viscosity index was lO9Ø Liquid chroma-tography analysis indicated 33.6% dimer C22 and 53.8% dimer C28 and 12.6% heavies. The ratio of dimer to trimer and heavies was thus 6.94:1. The TGA indicated 82.1% sample remaining.

2~

Oligomerization Oligomerization of a 70% C14 internal olefin - 30%
C8 alpha olefin mixture catalyzed by 2.5g BF3 and l.lg l-butanol as promoter was conducted starting at 75.1C. To a clean and dry 300 ml clave were added ll9g of C14 internal olefin and 51g of C8 alpha olefin of the same sources as the previous two examples, followed by l.lg of 1 butanol pro-moter. The clave was sealed and heated to 75.1C and at that temperature BF3 gas was added in increments (shots) over a 10 minute period. Five separate shots were applied to total 2.5g. Eleven minutes after the first BF3 addition, the reaction temperature had risen to 100.7C (a maximum exotherm of 25.6C). The reaction was held at 75C for 1.5 hours total and then cooled and worked up as in the previous examples. The dry product from this lower temperature olig-omerization had the following liquid chromatography analy-sis: 12-7% of monomer (C8, C14 and C16), % 22 42.1% of C28 and 21.5% of trimer and heavies. Conversion to materials greater than C16 was 87.3% with the dimer to trimer and heavies ~eing 3.07:1.
H~drogenatlon and stxiPping Hydrogenation of the oligomer from the above step was completed at 210C, 4.0 hours and 2,000 psig hydrogen pressure. Workup (filtration) followed by high vacuum strip-ping afforded a bottoms product which amounted to 70.7% of the charge and had the following properties: 210F viscos-ity of 4.16 cs, 25C viscosity of 34.5 cs, pour point of <-50F and a viscosity index of 124.2. The li~uid chroma-- 30 tography analysis indicated 16.7% of the material was C22, ' z~

56.8% was C2~ and 26.5% was heavies. TGA indicated the sample had excellent volatility (90% remaining a-t 233C).

Examples 30 - 35 were conducted in a manner similar to Examples 27 - 29 except that certain parameters were changed as shown in Table III.
Examples 36 - 38 were conducted according to the following procedure. Eighty three grams of delta 7 C14 and 36 g of delta 9 C18 internal olefin and 51g of C8 alpha ole-fin were added to a 300 ml Hastelloy clave followed by l.lg of 1-butanol. This olefin mixture is the closest approxi-mation to the U. S. Patent 4,300,006 feedstocks ob-tainable with the materials on hand. The clave was sealed and BF3 introduced in the indicated quantities. Workup was con-ducted as usual involving an a~ueous Na~C03 wash followed by two water washes and filtering the oryanic layer through filter paper to dry it. Hydrogenation was accomplished at 210C and in the presence of 5% (by weight, basis olefin) nickel catalyst and 2,000 psig hydrogen pressure for four hours. The hydrogenation product was filtered and distilled at high vacuum (<0.1 mm Hg) and to a head temperature of 110C. The bottoms product was submitted for analysis. The results of this last set of comparative examples are summar-ized in Table III.

%~
C ~ O O~ G~ 0~ 0~q ~ O O
g I ~q ~ O~ ~ ~ ~~ O O
XCC~C~ o l ~ 3~ ~20 3 -Q .~
- I o o ~ o.~, .q .q o o o '~ ~1 Lq ~ Lq C~l ~ ~ ~ L-~ L
~,O q O I I I I ,+ ~ ~
O '' P-~ ~I V V V V
.
9 O O C~ D ~q C~
,~ o ~1 o o~ ~ o~ oo Lq ~O
-1 :~ I ~ O C`~ O ~ C`l O O
~a ~
~ QJ ~ Lq ~ 0~ 'O ~ ~1 ~ O
-1 ~ '` ~n o Ll ~ ~J ~1 r-- L ~ `:t O L 0 1 1~
~ s.l ~n o O U~ ~ ~
o ~ o~ ~ lq'~'q~ ~. 3 a~ -~ O 1- ~) ~: C~ ~ ~ ~ ~I ~ ~ I ~ Lq~ ~ L~

O ~ tl ~ Lq Lq O~ O O C~l O~ ~Li O ~) _I Li ~ l Li Lq E-~ o ~ ~ 10 ~ 0 ~ 00 0:1 ~3 ~ ~qI
C ~
c~~n H V~S,J ~J ~ rl .. .. .. .. .. .. .. ..
3 H ~) E13 ?3~ o ~ Lq ~ oO ~ Lq P: :~ l~ ) ~~) O Lq 1-- ~q ~ ~
C ~1 oo ~ E-l ~ ~ I`~ q ~C) O O
1~0 O
~, ~ C ~ o ?
~ o ~ ~ ~
H ~ ~ .,.j ~ ~ ~ 3~Cr) L'') ~--I O ~ ~ C~ ~ r~
~ ~:; ~ ~ C~ ~ O o~
_~ ~ H ~ ~~qC~0~o ~ ~ 00 Cl~
~ O E-l E ~
Cl:) H~1 ~ r ~ C ~ 1~ C~ D O
Z ~Ll9 .~ .. . . . . ~
3 . ~ o Lq LqL~

e~
H ~ r~
P; ~ r~ LqC~LqLq~ D ~t ~ ~t L'~ r l L'') X ~ ~ ~ ~-1 ~1C~t~~iC~i C~i ~i Li Lrl ~J Li Li ~5 .
U C,J ~_I
~ E ::! . . . . ? . ? Lq Lq Lq Lq Lq O I ~ I O I ~-- I I I I I I I I I
~r-l ~ ~ ' C~ ~ ~ ' O ~t --I ~ O 0 1 0 ~ O LO O 00 C~
9 C~ ' O ' O ' O ' ~
') eQJ Lr~ Lq o L~ q Lq ~ ~ ~ ~I L~l c~ l L'~ ~ ~ C~l `J ~ Lq ~Y;
C~ ~ 0~ 0~ 0~ 0~ 0~ 0~ 0~ 0 . ~ L~
3 ¢ O O O O O O O O O O _ -~ 0 ~ ~ ~
U C_) C ) ?
O ~ Q) ~n ~ ~ ~J ~ ~ ~ ~ ~ ~ ~J ~ ~ ~ o~
a~ ~ 0~ 0~ O
OOOO0~OOOO0~
H I~ ~ + <¦ U

U~
c~ o~ o ~ c~ ~ ~ Lq ~D ~ C~
c~ ~ c~ cq ~q ~ ~ c~ ~ ~ ~ ~ -c As can be seen from Table III, the product from the feedstoc~s used in U. S. Patent 4,300,006 are unsuitable for use as a synthetic lubricant without furthex distillation;
i.e., the bottoms product foun~ useful using the internal olefin feedstocks of the invention are superior. Examples 32 - 38 have 210F and/or 25C viscosities and/or pour points which are too high for use as 4 cs synthetic lubricants.
One skilled in the art would not expect these materials to pass cold cranking tests. These same feedstocks, when run at a higher temperature, produce a material with a low vis-cosity index and a poor TGA value (see Example 31).
~ hus, it is determined by comparative examples using the conditions of U. S. Patent 4,300,006 that the re-sulting products would need to be distilled in ordex to meet the 4.0 cs 210F viscosity re~uirement and apparently -the cold cranking specifications as well.
The oligomer mixtures produced from Cl3 14 in-ternal olefins via a promoted BF3 catalyst have proven to be exceptional synthetic lubricant additives. As these mix-tures have a 210F viscosity of about four centistokes, theyare considered "4 cs" fluids. A typical fluid of this in-vention was compared with the commercially available 4 centistoke decene-1 derived polyalpha olefin (PAO). It should be emphasized that the synthetic lubricant components of the instant invention are preferably used without further distillation after the monomer removal and hydrogenation steps.
In other words, the undistilled bottoms are the finished syn-thetic lubricant component. The polyalpha olefins must be distilled into "2 cs", "4 cs", "6 cs", etc. fractions before - 30 they can be useful. Thus, the method of this invention does not require a costly distillation step, which is an important advantage over methods used by others in the field. Compari-son of the properties of the fluids themselves are given in Table IV. It may be seen that the fluid of this invention (A) is somewhat less viscous than the polyalpha olefin fluid (B) at the higher temperatures, though it is somewhat more viscous at the lower temperatures. The viscosity index for fluid A is somewhat less than for fluid B, but they are generally comparable.

TABLE IV

TESTS A * B
Kinematic Viscosity, cs at C F
100.0 212.0 3.81 3.90 40.0 104.0 17.0 17.1 Brookfield Viscosity, centipoise at C F
-28.g -20.0 800 780 -40.0 -40.0 2340 2200 Viscosity Index 115 123 10 Pour Point, F** <-65 <-65 Gravity, API 40.8 41.1 Flash, C0C, F 430 435 CCS Viscosity, cP, -30C 980 930 ASTM color 0.0 0.0 Ash, % 0.001 0.001 *A = Fluid of this invention B = Polyalpha olefin fluid ** = The actual pour points of the synthetic base oils were less than 65F, the lowest temperature at which pour points could be measured with available equipment.

~ 30 A measure of the volatility of the two fluids is presented in Table V where it may be seen that oligomer A
is more volatile than fluid B.

TABLE V

A B
ASTM Eva~oration Test Wt.% loss, 400F/6.5 hr 16.9 14.8 Thermal Gravimetric Anal~sis Wt.% remaining at ~33C 91 92 Simulated Distillation Wt.% off column, F
Initial Boiling Point 687 619 ~ 710 737 4 71~ 761 7~5 785 Two motor oils were formulated having the same proportions of the same components, except that formulation A
had 35 wt.% of a 4 cs fluid of this invention and formu-lation B had 35 wt.% of the polyalpha olefin 4 cs fluid.
The rest of the components of the two formulations are identical in type and proportion and include materials such as mineral oils, dispersants, antioxidants, detergents, friction modifiers, rust inhibitors, viscosity index im-provers, pour point depressants and antifoamants. The proportion of 35 wt.% is large enough for the additives to - 30 have a profound effe~t on the behavior of the formulations TABLE VI
PROPERTIES OF MOTOR OIL FORMULATIONS

A_ B Grade 1imits Kin. vis. at 100C, cs 9.48 9.54 9.3 to 12.5 CCS vis. at -25C, cP 3500 3450 3500 max.
MBPT, ~C -34.7 -34.1 -30 max.
Pour Point -40 -45 TABLE VII
ENGINE TEST RESULTS
API SF/CC
TESTS A B GRADE LIMITS
SEO IIID TEST
Oxidation Stability Test Vis. Inc.1, % at 64 Hr. 28 242 375 max.
Sludge 9.6 9.6 9.2 min.
Varnish 9.2 9.2 9.2 min.
ORLD2 8.0 7.1 4.8 min.
C~L3 Wear Average, inch 0.0021 0.0011 0.0040 max.
Maximum, inch 0.0035 0.0027 0.0080 max.
Ring Sticking None None None Lifter Sticking None None None Cam +/or Lifter Scuffing None None None Oil Consumption, quarts 5.0 6.47 6.38 max.

Bearinq Corrosion BWL~, mg 24.3 45.9,39.5 40.0 max.
CAT lH-2 TEST
Diesel Plston Deposits Test 120 Hour TGF5, % 13.0 4.0 WTD6 25.6 71.9 480 Hour TGF, % 15.5 5.0 45 max.
WTD 96.5 137.1 140 max.
1Viscosity increase 2Oil ring land deposits 3Cam and Lifter 4Bearing Weight Loss 5Top Groove Filling 6Weighted Total Demerits in testing. The properties of the motor oil formulations are given in Table VI.
The results of the engine tests of the two formu-lations are presented in Table VII. The engine tests run on the two formulations are standard tests well known to those skilled in the art. Sequence IIID tests are oxidation sta-bility tests designed to measure the wear protection char-acteristics; that is, to measure how the oils protect in-ternal loaded engine components against excessive wear. The engine is run at high speed under high loads. The first measurement is the per cent increase in 40~C viscosity after 64 hours. It is surprising to note that formulation A had a much lower viscosity change than did formulation B when it is remembered that oligomer mixture B had a higher viscosity index (indicating less change of viscosity with temperature) than did oligomer mixture B ~see Table IV). What is also surprising is -that formulation B required 6.47 quarts of oil for the Se~uence IIID tests, whereas formulation A required only 5.0 quarts. This result is contrary to what would be expected from the volatility information derived from the simulated distillation set out in Table V. It is particu-larly surprising when it is realized that the 4 cs fluid of this invention comprises only about 25% heavies. One skilled in the art would expect the more volatile material ~A) to cause any formulation made therefrom to require more oil.
However, as may be seen in Table VII, it is formulation B, having the less volatile oligomer mixture, which has the greater quantity requirements.
In the rest of the sequence IIID tests, the two - 30 formulations were quite comparable. ~owever, formulation A

again gives better results in the Coordinating Research Council L-38 test, which is a measure of bearing corrosion by measuring the weight loss of the bearing. In the first determination, formulation B failed the test with a weight loss of 45.9 mg, though it passed on a second attempt with 39.5 mg loss. Formulation A caused a much lower weight loss of 24.3 mg.
The Caterpillar 1~2 test is test measuring the accumulation of deposits on diesel pistons, among other cri-teria. Demerits are assigned in this test by the subjectiveopinion of a person approved by API (American Petroleum In-stitute). Although formulation A performed poorer than formulation B in the amount of top groove filling found, the weighted total demeri-ts for both durations for formulation A
was much less than that for formulation B. These results are further evidence of the surprisingly superior character-istics of the oligomer mixtures made from only internal ole fins and a promoted BF3 catalyst.
Many modifications may be macle in the method OI

this invention without departing fxom its scope which is de~
fined only by the appended claims. For example, it would be expected that one skilled in the art could change the BF3 promoter, the temperature, pressure, modes of addition or the olefin molecular weight in trying to maximize the con~
version or the oligomer properties.

;

Claims (62)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A process for oligomerizing mono olefins com-prising contacting a mixture of olefins having between 9 and 24 carbon atoms, inclusive, and having 99 weight per cent or more of internal olefins, with a catalyst comprising boron trifluoride under conditions sufficient to effect oligomeri-zation of said olefins.

2. The process of claim 1 in which a promoter is employed in connection with the catalyst, the promoter being selected from the group consisting of alcohols, carboxylic acids and water.

3. The process of claim 2 in which the promoter is l-butanol.

4. The process of claim 1 in which the oligomeri-zation is conducted at a temperature between about 25 and about 150°C.

5. The process of claim 1 in which the oligomer-ized olefins are hydrogenated.

6. The process of claim 1 in which the double bond of the olefin is randomly distributed throughout the carbon chain.

7. A synthetic lubricant component prepared accord-ing to the process of claim 1 or 5.

8. A synthetic lubricant component having a vis-cosity at 210°F of between 3.5 and 5.0 centistokes, a vis-cosity at 25°C of between 25 and 40 centistokes, a vis-cosity index of greater than 100 and a thermogravimetric analysis value of greater than 80 weight per cent, being produced by oligomerizing a mixture of internal olefins having between 9 and 24 carbon atoms inclusive by means of reacting the mixture of olefins in the presence of a boron trifluoride catalyst under oligomerization conditions.

9. The synthetic lubricant component of claim 8 in which the number of carbon atoms in the internal olefins of the mixture is between 11 and 14, inclusive.

10. The synthetic lubricant component of claim 9 in which the number of carbon atoms in the internal olefins of the mixture is 13 or 14.

11. The synthetic lubricant component of claim 8 in which the oligomerization is conducted in the presence of a protonic promoter selected from the group consisting of alcohols, carboxylic acids and water.

12. The synthetic lubricant component of claim 11 in which the protonic promoter in the oligomerization is 1-butanol.

13. The synthetic lubricant composition of claim 8 in which the oligomerization is conducted at a temperature between 25 and 150°C.

14. The synthetic lubricant component of claim 8 in which one or more mild stripping steps to remove any un-reacted olefin monomer constitutes the only separation steps.

15. The synthetic lubricant component of claim 14 in which any mild stripping is conducted at a temperature between 150 and 180°C.

16. The synthetic lubricant component of claim 8 in which the oligomerized olefins are hydrogenated.

17. The synthetic lubricant component of claim 16 in which the oligomerized olefins are hydrogenated over a hydrogenation catalyst selected from the group of catalysts consisting of nickel-copper-chromium and cobalt-copper-chrom-ium.

18. The synthetic lubricant component of claim 8 in which the double bond of the olefins is randomly dis-tributed throughout the carbon chain.

19. A process for producing a synthetic lubricant component comprising a. contacting a mixed internal olefin feed-stock comprising a plurality of internal olefins having the formula RCH=CHR' where R and R' are the same or different alkyl radicals of 1 to 21 carbon atoms, except that the total number of carbon atoms is greater than or equal to 9 or less than or equal to 24, with a boron tri-fluoride catalyst under oligomerization conditions, and b. separating the oligomerized olefins from the unreacted olefin monomers under mild stripping conditions as the only sep-aration step.

20. A process for the production of a synthetic lubricant component comprising oligomerizing a mixture of olefins having between 9 and 24 carbon atoms inclusive, the mixture being comprised of 99 weight per cent or more in-ternal olefins, comprising reacting the mixture of olefins in the presence of a boron trifluoride catalyst under olig-omerization conditions to produce a synthetic lubricant component having a viscosity at 210°F of between 3.5 and 5.0 centistokes, a viscosity at 25°C of between 25.0 and 40.0 centistokes, a viscosity index of greater than 100 and a thermogravimetric analysis value of greater than 80 weight per cent.

21. A process for the production of a synthetic lubricant component comprising oligomerizing a mixture of internal olefins having between 11 and 14 carbon atoms in-clusive, comprising reacting the mixture of olefins in the presence of a boron trifluoride catalyst under oligomeri-zation conditions to produce a synthetic lubricant component having a viscosity at 210°F of between 3.5 and 5.0 centi-stokes, a viscosity at 25°C of between 25.0 and 40.0 centi-stokes, a viscosity index of greater than 100 and a thermo-gravimetric analysis value of greater than 80 weight per cent.

22. A process for the production of a synthetic lubricant component comprising oligomerizing a mixture of internal olefins having 13 or 14 carbon atoms inclusive, comprising reacting the mixture of olefins in the presence of a boron trifluoride catalyst under oligomerization con-ditions to produce a synthetic lubricant component having a viscosity at 210°F of between 3.5 and 5.0 centistokes, a viscosity at 25°C of between 25.0 and 40.0 centistokes, a viscosity index of greater than 100 and a thermogravimetric analysis value of greater than 80 weight per cent.

23. A process for the production of a plurality of synthetic lubricant components comprising a. oligomerizing a mixture of internal ole-fins having between 9 and 24 carbon atoms inclusive, comprising reacting the mixture of olefins in the presence of a boron trifluoride catalyst under oligomerization conditions, b. mildly stripping the unreacted olefin monomer from the crude oligomer product, c. distilling the crude oligomer product into components of different viscosity, each having a viscosity index of greater than 100 and a thermogravimetric analy-sis value of greater than 80 weight per cent.

24. The process of claim 19, 20 or 21 in which a protonic promoter is present with the boron trifluoride catalyst, the protonic promoter being selec-ted from the group consisting of alcohols, carboxylic acids and water.

25. The process of claim 19, 20 or 21 in which 1-butanol is employed as a protonic promoter together with the boron trifluoride catalyst.

26. The process of claim 19, 20 or 21 in which the oligomerization is conducted at a temperature between 25 and 150°C.

27. The process of claim 19 or 23 in which the mild stripping step is conducted at a temperature between 160 and 180°C.

28. The process of claim 19, 20 or 21 in which the synthetic lubricant component is hydrogenated over a hydrogenation catalyst selected from the group of catalysts consisting of nickel-copper-chromium and cobalt-copper-chromium.

29. The process of claim 19, 20 or 21 in which the double bond of the olefins is randomly distributed throughout the carbon chain.

30. A synthetic lubricant component prepared according to the process of claim 19, 20 or 21.

31. A synthetic lubricant component comprising a hydrogenated mixture of oligomers of internal olefins having between 9 and 24 carbon atoms inclusive, the mixture having a 210°F viscosity between about 3.5 and 5.0 centistokes, a 25°C viscosity between about 25 and 40 centistokes, a vis-cosity index of greater than 100 and a thermogravimetric analysis value of greater than 80 weight per cent remaining at 233°C, the oligomers being composed of two or more but less than 10 oligomer units.

32. The synthetic lubricant component of claim 31 in which the internal olefins have between 11 and 14 carbon atoms, inclusive.

33. The synthetic lubricant component of claim 31 in which the internal olefins have 13 or 14 carbon atoms.

34. The synthetic lubricant component of claim 31, 29 or 30 in which the oligomerization of the internal ole-fins is performed over boron trifluoride.

35. The synthetic lubricant component of claim 31, 29 or 30 in which the hydrogenation of the oligomers is per-formed over a hydrogenation catalyst selected from the group of hydrogenation catalysts consisting of nickel-copper-chromium and cobalt-copper-chromium.

36. The synthetic lubricant component of claim 31 in which the olefins have the double bond randomly distributed throughout the carbon chain.

37. A process for the production of a synthetic lubricant component comprising a. oligomerizing a mixture of olefins having between 9 and 24 carbon atoms inclusive, the mixture being comprised of 99 weight per cent or more internal olefins, com-prising reacting the mixture of olefins in the presence of a boron trifluoride catalyst and a protonic promoter at a temperature sufficient to produce a crude oligomer product, b. neutralizing the crude oligomer product, c. removing the organic layer from the neutralized crude oligomer product, and d. mildly stripping the unreacted olefin monomer from the organic layer of the crude oligomer product as the only sep-aration step.

38. The process of claim 37 in which the protonic promoter of the oligomerization step a. is selected from the group consisting of alcohols, carboxylic acids and water.

39. The process of claim 38 in which the protonic promoter of the oligomerization step a. is 1-butanol.

40. The process of claim 37 in which the olig-omerization step a. is conducted at a temperature between 25 and 150°C.

41. The process of claim 37 in which the mild stripping step d. is conducted at a temperature between 160 and 180°C.

42. A synthetic lubricant component prepared according to the process of claim 37.

43. A process for the production of a synthetic lubricant component comprising a. oligomerizing a mixture of olefins having between 9 and 24 carbon atoms inclusive, the mixture being comprised of 99 weight per cent or more internal olefins in which the double bond is randomly dis-tributed throughout the carbon chain, comprising reacting the mixture of ole-fins in the presence of a boron tri-fluoride catalyst and a protonic promoter at a temperature sufficient to produce a crude oligomer product, b. neutralizing the crude oligomer product, c. removing the organic layer from the neutralized crude product, d. mildly stripping the unreacted olefin monomer from the organic layer of the crude oligomer product, and e. hydrogenating the stripped oligomer product without further separation.

44. The process of claim 43 in which the protonic promoter of the oligomerization step a. is selected from the group consisting of alcohols, carboxylic acids and water.

45. The process of claim 44 in which the protonic promoter of the oligomerization step a. is 1-butanol.

46. The process of claim 43 in which the oligomeri-zation step a. is conducted at a temperature between 25 and 150°C.

47. The process of claim 43 in which the mild stripping step d. is conducted at a temperature between 160 and 180°C.

48. The process of claim 43 or 47 in which hydro-genation step e. is followed by a second mild stripping step to remove monomer missed in the first stripping step.

49. The process of claim 43 in which the hydro-genation step e. is conducted over a hydrogenation cat-alyst selected from the group of catalysts consisting of nickel-copper-chromium and cobalt-copper-chromium.

50. A process for the production of a synthetic lubricant component having a viscosity between 3.5 and 5.0 centistokes at 210°F, comprising a. oligomerizing a mixture of olefins com-prising 97 weight per cent or more of olefins having 13 or 14 carbon atoms and 99 weight per cent or more internal olefins in which the double bond is randomly distributed throughout the carbon chain, comprising reacting the mixture of olefins in the presence of a boron trifluoride catalyst and a protonic promoter at a temperature sufficient to produce a crude oligomer product, b. neutralizing the crude oligomer product, c. removing the organic layer from the neutralized crude oligomer product, d. mildly stripping the unreacted olefin monomer from the organic layer of the crude oligomer product, at a temper-ature below 180°C, and e. hydrogenating the stripped oligomer product without further separation.

51. The process of claim 50 in which the vis-cosity of the synthetic lubricant component is about 4 centistokes at 210°F.

52. The process of claim 50 in which the protonic promoter of the oligomerization step a. is selected from the group consisting of alcohols, carboxylic acids and water.

53. The process of claim 52 in which the protonic promoter of the oligomerization step a. is 1-butanol.

54. The process of claim 50 in which the oligomerization step a. is con-ducted at a temperature between 25 and 150°C.

55. The process of claim 50 in which the mild stripping step d. is con-ducted at a temperature between 160 and 180°C.

56. The process of claim 50 or 55 in which hydrogenation step e. is fol-lowed by a second mild stripping step to remove monomer missed in the first stripping step.

57. The process of claim 50 in which the hydrogenation step e. is con-ducted over a hydrogenation catalyst selected from the group of catalysts con-sisting of nickel-copper-chromium and cobalt-copper-chromium.

58. A synthetic lubricant base oil component prepared according to the process of claim 50.

59. The process of claim 22 or 23 in which a pro-tonic promoter is pres-ent with the boron trifluoride catalyst, the protonic promoter being selected from the group consisting of alcohols, carboxylic acids and water.

60. The process of claim 22 or 23 in which 1-butanol is employed as a protonic promoter together with the boron trifluoride catalyst.

61. The process of claim 22 or 23 in which the oligomerization is con-ducted at a temperature between 25 and 150°C.

62. The process of claim 22 or 23 in which the synthetic lubricant com-ponent is hydrogenated over a hydrogenation catalyst selected from the group of catalysts consisting of nickel-copper-chromium and cobalt-copper-chromium.