US3730877A - Process for the preparation of base oils for the production of lubricating oil - Google Patents

Abstract

HIGH VISCOSITY INDEX LUBRICATING BASE OILS ARE PREPARED BY TREATING PARAFFINIC-NAPHTHENIC OILS HAVING A LOW AROMATIC CONTENT AND A HIGH CONTENT OF NAPHTHENES WITH CONDENSED RINGS WITH HYDROGEN IN THE PRESENCE OF PLATINUM ON ALUMINA CATALYST CONTAINING NOT MORE THAN 4% WT. OF AN ALKALI OR ALKALINE EARTH METAL AT A HYDROGEN PARTIAL PRESSURE ABOVE 10 KG./CM.2 AND A TEMPERATURE OF AT LEAST 345*C.

Description

United States Patent O 3,730,877 PROCESS FOR THE PREPARATION OF BASE OILS FOR THE PRODUCTION OF LUBRICATING OIL Willem C. J. Quik and Pieter A. van Weeren, Amsterdam, Netherlands, assignors to Shell Oil Company, New York, NY. No Drawing. Filed Dec. 5, 1968, Ser. No. 781,628 Int. Cl. (110g 23/04 US. Cl. 208-143 4 Claims ABSTRACT OF THE DISCLOSURE High viscosity index lubricating base oils are prepared by treating paraffinic-naphthenic oils having a low aromatic content and a high content of naphthenes with condensed rings with hydrogen in the presence of platinum on alumina catalyst containing not more than 4% wt. of an alkali or alkaline earth metal at a hydrogen partial pressure above kg./cm. and a temperature of at least 345 C.

BACKGROUND OF THE INVENTION Field of the invention The invention relates to a process for the preparation of high-viscosity-index base oils for the production of lubricating oil by treating a paraffinic-naphthenic hydrocarbon oil with hydrogen in the presence of a catalyst which contains platinum as active metal component.

Description of the prior art As is known it is impossible to produce lubricating oils with a high viscosity index (HVI) from highly naphthenic crude oils in a conventional manner since it is precisely those components, viz. the paraifinic and isoparaflnic hydrocarbons imparting good lubricity to the finished lubricating oil, which relatively speaking, are present in small amounts. The term HVI lubricating oils includes oils which have a viscosity index (VI) of more than 80 according to the Dean and Davis method. It is especially the naphthenic hydrocarbons with condensed rings, the polynaphthenes, which have poor lubricating properties and exercise an unfavourable influence on the viscosity index of the finished lubricating oil. Mononaphthenes boiling in the lubricating oil range have no adverse effect.

However, if for the production of lubricating oil only paraffinic-naphthenic base oils with a relatively high content of naphthenes are available means other than those conventionally used should be employed in order to produce HVI lubricating oils therefrom. One of these means is a catalytic hydrogen treatment of the unsuitable base oils under circumstances which cause the naphthenic com pounds to be converted into non-naphthenic lubricating oil components. In this way the ratio of the lubricating oil components to one another can be modified in such a manner that the base oil thus treated has improved properties. It has been proposed in the literature to bring a hydrocarbon oil fraction which substantially boils above 285 C. and contains naphthenes with condensed rings into contact with hydrogen in the presence of a hydrogenation catalyst such as platinum metal on a non-acidic carrier. This is effected under such conditions of temperature and pressure that the naphthenic compounds are dehydrogenated to aromatic hydrocarbons.

The aforementioned method of converting naphthenic compounds into other hydrocarbons has its drawbacks. The first is that aromatic or alkyl-substituted aromatic compounds are less desirable lubricating oil components because they have poor lubricity. Thus, in order to obtain a lubricating base oil with improved properties the aromatic compounds formed should be removed. However,

this involves a reduction in the yield of base oil relative to the feed used as starting material, which constitutes a second drawback. The latter drawback will be aggravated according as more naphthenic components have been converted into aromatic components.

Another method previously proposed for the production of lubricating oil is hydrocracking of the base oil. By means of this method it is generally possible to improve, i.e. to raise the viscosity index of base oils for lube oil production. However, this method cannot be continued indefinitely because hydrocracking is a destructive method so that the resultant amount of base oil boiling in the same boiling range becomes smaller and smaller. Further, it has been found that together with the decreasing yield the viscosity of the base oil also diminishes.

As used in this application base oil for the production of lubricating oil is understood to mean any hydrocarbon oil or oil fraction suitable for the production of lubricating oils. The greater part of such a base oil boils above 300 C. and from this base oil the various lubricating base oils such as spindle oil, light, medium and heavy machine oil, cylinder oil and the like are obtained, which lubricating base oils after a possible further treatment such as colour improvement, dewaxing, etc., yield the various fractions which may serve as finished lubricating oils either as such or after addition of additives. Base oils having a VI of and more considered to be VHI oils; if desired the viscosity indices of the lubricating base oils can be further increased by conventional methods.

The object of the invention is to produce base oils with a high-viscosity-index by starting from paraifinic-naphthenic hydrocarbon oils or oil fractions. It is a further object of the invention to convert the naphthenic components in these oils into components which are valuable for the lubricating properties of the lubricating oil. Another object of the invention is to improve the viscosity index of the base oil while retaining a good viscosity.

SUMMARY OF THE INVENTION According to the process of the invention high-viscosityindex base oils for the production of lubricating oil are obtained by treating a parafiinic-naphthenic hydrocarbon oil with hydrogen in the presence of a catalyst which contains platinum as active metal component. The process is characterized in that a parafiinic oil which is poor in aromatics and has a high content of naphthenes with condensed rings is contacted with hydrogen in the presence of a basic catalyst consisting of more than 0.5% by weight of platinum on alkali metal or alkaline earth metal-containing alumina at a partial hydrogen pressure of more than 10 kg./cm. and a temperature of at least 345 C. The catalyst preferably contains 15% by weight of platinum metal.

The feed which is used in the process according to the invention should be a paraffinic oil or oil fraction which is poor in aromatics and has a high content of naphthenes with condensed rings. A feed of this type can be composed by blending suitable hydrocarbon oil fractions which are poor in aromatics or may be obtained from paraflinicnaphthenic crude oils. If such oils have a high content of aromatic compounds the oil or oil fraction to be used as feed for the preparation of a base oil should first be treated in a conventional manner to remove aromatics.

Oil poor in aromatics is understood to mean an oil or oil fraction which contains not more than 10% of carbon occurring in an aromatic structure. Preferably the oil contains less than 7% and more preferably less than 5% of carbon in an aromatic structure. A suitable feed by means of which hydrocarbon oils can be obtained as starting material for the process of the invention is a waxy distillate of a paraflinic-naphthenic crude oil boiling above 350 C. Alternatively, the fed may be a paraifinic, highlv catalytically cracked cycle oil boiling for example between 350 C. and 510 C. Such a cycle oil should first be wholly or partly freed from aromatics, for example by extraction with a selective solvent for aromatics in order to obtain a feed which is poor in aromatics. The feed may also be a de-asphalted residual oil or a fraction thereof obtained by vacuum distillation of a paraffinic-naphthenic crude oil and de-asphalting of the residue with a lowboiling hydrocarbon such as propane, butane, pentane or mixtures thereof.

A suitable method for determining whether the feed to be used contains less than 10% of carbon in aromatic structure is by means of infra-red analysis.

Preference is given to a paraflinic oil boiling above 350 C. which is poor in aromatics and has a high content of naphthenes with condensed rings. The parafiin content of the oil may be very low; good results have been obtained with a paraflin content of less than 20% by weight. In general, use can suitably be made of hydrocarbon oils with a paraflin content of 50% by weight. Although hydrocarbon oils with a higher parafiin content, for example of 50-75% by weight are suitable for use according to the process of the invention there will in general be no need for them. The content of mononaphthenes in the oil used may vary from -50% by weight, the remainder of the oil consisting of di-, tri-, and higher polynaphthenes.

The investigation carried out in connection with the process of the invention revealed that there is a definite relationship between the viscosity in centistokes at 210 F. (99 C.) and the viscosity index of an oil fraction with regard to the base oils having the same boiling range to be prepared therefrom. This relationship for the saturated compounds of a highly refined aromatic-free paraffinic-naphthenic oil fraction with a VI of 80 and a viscosity of 8.11 at 210 F. and for the base oils obtained therefrom according to the invention after removal of the aromatics shows that the portion of the oil fraction which boils above 375 C. has a viscosity of about 8.5 at 80 VI which drops linearly to about 5.2 at 110 VI.

Hence it follows from the aforesaid relationship that starting from a given oil fraction it is impossible in practice to produce any type of HVI base oil or lubricating oil. For luboil applications it is desirable however that the lubricating oils to be used should combine a high V1 with a good viscosity at 210 F. In addition there is the fact that the higher the viscosity index the lower will be the yield of base oil with this VI and boiling in the same range. Consequently, continued refining and/or distillation of the base oil may lead to a product with very high Vls but the yield is small. In the production of lubricating oil the refiner will therefore have to compromise between an economically justified yield and the maximum attainable VI consistent therewith.

Using a given parafiinic-naphthenic hydrocarbon oil or oil fraction as starting material, the process of the invention now makes it possible to prepare base oils with a high VI and a relatively high viscosity at 210 F. with a good yield of base oil. Without wishing to be tied down by any particular theoretical explanation applicants believe that according to the process the monoand polynaphthenes are split open to give parafiins and naphthenes with a lower number of condensed rings, respectively, but with retention of substantially the same molecular weight. Furthermore dealkylation will take place but cracking will occur to a minor extent only. As a result of the described reaction the content of parafiinic and mononaphthenic hydrocarbons in the treated base oil with rise. The use of the process according to the invention has therefore the advantage that the polynaphthenes which are detrimental to the lubricating properties of the lubricating base oils are converted into compounds of a more parafiinic nature without involving a large drop in molecular Weight. Since the viscosity of an oil is dependent on the presence of high-molecular compounds a base oil with a good viscosity will be obtained, while the increase in the quantity of parafiins at the expense of the naphthenes causes a relatively sharp rise in the viscosity index of the base oil. At the same time an improved yield of HVI base oil is obtained.

In addition to ring-opening of the naphthenes, dehydrogenation of the naphthenes to aromatics also takes place in the process according to the invention. The higher the reaction temperature used the higher will be the aromatics content of the resultant base oil. The aromatics formed can be removed in a conventional manner such as by liquid extraction, hydrogenation or adsorption on solid adsorbing agents, if this is desired for the preparation of lubricating base oils with very high viscosity indices.

The alkali metal or alkaline earth metal-containing alumina used as catalyst carrier preferably contains not more than 4% by weight of alkali or alkaline-earth and more preferably the alumina contains 0.05-2.5% by weight of alkali or alkaline earth. Good results have been obtained in particular with 0.050.5% by weight. The alkali metal used is preferably sodium or potassium. Further, the alumina used should be halogen-free. As basic carrier use can be made of any commercially available alumina which has an alkali or alkaline earth content within the specified range. However, if the commercial product is non-basic or has a relatively high content of halogens such as chlorine and/or fluorine, it can first be treated with steam, hot water or ammonia. After drying and/ or calcination the desired content of alkali metal or alkaline earth metal can be applied by subjecting the alumina to a treatment with an alkali metal or alkaline earth metal salt solution in a manner known per so such as impregnation or percolation. On the carrier thus prepared, preferably after it has been dried and/ or calcined, the platinum metal is deposited by means of impregnation with or percolation of a solution of a soluble platinum salt. After having once more been dried and calcined the catalyst is ready for use.

It should be noted that the catalyst is used in the form in which the platinum is present on the carrier as platinum metal. The reduction of the platinum compound to platinum metal by means of hydrogen usually takes place in the reactor prior to the actual process for the conversion of paratfinic-naphthenic hydrocarbon oils into the desired base oil.

As catalyst carrier use is preferably made of an alumina obtained by means of an alkali-free mode of preparation and the alkali metal or alkaline earth metal content of which is adjusted by applying the calculated amount of alkali metal or alkaline earth metal as described above. As example of an alkali-free mode of preparation reference may be made to hydrolysis of aluminium trichloride by means of ammonia. Aluminas of this type are commercially available; if their chlorine content is too high they can be made substantially free of chlorine by means of a steam treatment. The deposition of the desired alkali metal or alkaline earth metal content is preferably effected after calcination of the alumina. The alkali metal or alkaline earth metal is preferably deposited by using the corresponding carbonate solution.

The parafiinic-naphthenic oil is preferably passed over the basic catalyst at a partial hydrogen pressure below kg./cm. A pressure of 50-75 kg./cm. was found to be highly suitable. However, the pressure to be employed should be in excess of 10 kg./cm. because with pressures lower than 10 kg./cm. there is only dehydrogenation of the naphthenes into aromatics and no ring opening to form valuable paraffinic components. The liquid hourly space velocity used may vary from 0.5 to 5 litres of feed per litre of catalyst per hour, while a hydrogen/feed ratio of IOU-10,000 normal litres of hydrogen per litre of feed can be conveniently used.

Preferably a temperature of 375450 C. is used. The higher the temperature used the better will be the dehydrogenation reaction with the formation of aromatics. It is advisable therefore to select the remaining reaction conditions in such a manner that the lowest possible temperature can be employed.

The process according to the invention can be used with a hydrocarbon oil which contains 5000' p.p.m. of sulphur. The effect of using sulphur is two-fold, on the one hand it reduces the activity of the catalyst so that with the conversion remaining unchanged a higher temperature is required and therefore a higher production of aromatics, while on the other hand a base oil is obtained which after removal of aromatics shows a higher VI than without the use of sulphur although the yield is lower. Consequently, the use or non-use of sulphur according to the process of the invention enables the refiner to produce particular grades of lubricating oil, depending on demand.

As noted previously, the hydrocarbon oils which are used as starting material for the production of a base oil according to the invention should first be free from aromatics if any are present. These oils can be made poor in aromatics by extraction of the aromatics with a selective solvent such as phenol, sulphur dioxide, furfural, sulpholane and the like or by means of selective adsorption with a solid adsorbing agent such as silicagel, activated carbon, attapulgus clay or the like. This is a conventional method known in the art. It is also possible to make aromatic hydrocarbon oils poor in aromatics by means of catalytic hydrogenation of the aromatics into naphthenes. Within the scope of the present invention a hydrogenation of this type is preferred since this is beneficial to the ultimate yield of base oil based on the starting material. If in addition the aromatic oil also contains sulphur compounds in an undesirable quantity, hydrogenation offers the advantage that these sulphur compounds are removed simultaneously.

If a starting material is available as feed for the process of the invention which is rich in aromatics and poor in sulphur or if such a feed has already been freed from sulphur in another way, suitable catalysts for the hydrogenation of aromatics are for example the commercially available hydrogenation catalysts. Examples of suitable catalysts are those which contain nickel or metals of the platinum group (or their compounds). As examples may be mentioned a nickel-kieselguhr catalyst with 40-65% by weight of nickel, a rhodium on alumina catalyst with 0.5% by weight of rhodium or a platinum on aluminum catalyst with for example 0.1-2% by weight of platinum.

If simultaneously with the hydrogenation of aromatics sulphur compounds are to be removed, the catalyst used is preferably a desulphurization catalyst, in particular catalyst, in particular catalysts which are insensitive to hydrogen sulphide. Suitable desulphurization catalysts are formed by the metals and/or their oxides or sulphides from the 6th and/or 8th Group of the Periodic Table, supported preferably on a suitable refractory, oxidic carrier with a large surface area. Preferably use is made of catalysts which contain cobalt, molybdenum, tungsten, nickel or their combinations, in the form of their oxides or sulphides. Suitable carriers are formed by alumina, silica, magnesia, boria, zirconia and the like or combinations thereof such as silica-alumina, silica-boria or silicamagnesia. Use can also be made of fullers earth, kieselguhr or activated carbon.

It will be clear that the desulphurization catalysts discussed above can also be used if the hydrocarbon oils to be processed are only to be freed from sulphur compounds.

During the hydrogenation of aromatics, in particular when using the aforesaid desulphurization catalysts, it is essential that cracking reactions and consequently reduction of the molecular weight of the paraffinic-naphthenic feed oil should be prevented as much as possible. To this end use will preferably be made of weakly acidic catalyst carriers and/or the operation will be carried out under such conditions that cracking reactions are suppressed.

The hydrogenation of aromatics and/ or the desulphurization can be carried out at temperatures and pressures which may vary within Wide limits. As examples may be mentioned pressures varying from 20-275 kg./cm. in particular from 60250 kg./cm. and temperatures of 200-540 C., in particular of 300-524 C. For a combined hydrogenation of aromatics and desulphurization the temperature and pressure employed will usually be such as to ensure that both reactions lead to an optimum effect. A suitable temperature and pressure are 400 C. and 200 kg./cm. respectively.

The liquid hourly space velocity during the hydrogenation of aromatics and/or the desulphurization and the hydrogen/oil ratio may likewise vary within wide limits. As examples may be mentioned liquid hourly space velocities of 0.25-5 litres of oil per litre of catalyst per hour and a hydrogen/oil ratio of -5000 normal litres/litre.

As source of hydrogen for the processes discussed above as well as for the process of the invention pure hydrogen or for example waste gases originating from catalytic reforming processes may be used.

In the process of the invention aromatics are also formed. Depending on the desired luboil application the resulting base oil can be treated to remove aromatics by one of the methods discussed above.

From the reaction product obtained according to the process of the invention the desired base oil is isolated as the product boiling above 350 C, preferably above 375 C. The resultant base oil as such may be used as lubricating base oil or it may be split into two or more lubricating base oils by fractional distillation. The base oil or the lubricating base oils may now be subjected, if desired, to any of the treatments customarily used in the production of lubricating oils in order to improve the quality, such as improvement of the colour and/ or colour stability, and reduction of the pour point and/ or aromatics content. Such treatments are acid treatment, clay treatment, mild hydrogen treatment, dewaxing, removal of aromatics and the like. With regard to the dewaxing it may be noted that the removal of parafiin (wax) by means of dewaxing may also be effected with the hydrocarbon oil or oil fraction prior to carrying out the process of the invention.

The process according to the invention may be carried out in any manner desired. It is possible for example to use a fluidised catalyst bed or a fixed bed; the oil to be treated together with the hydrogen may be passed through the bed in an upward or a downward direction while the oil and/or hydrogen may or may not be recycled. Such techniques are widely known and need no further description here.

The invention will be elucidated by the following examples. As is customary for lubricating oils the viscosity of the hydrocarbon oils is given at a temperature in degrees Fahrenheit. After the hydrogen treatment over the catalyst of the invention the fraction boiling above 375 C. which is invariably isolated from the reaction product as the desired base oil. The content of saturated com pounds in this base oil is determined after removal of aromatics by means of percolation of the said fraction over silicagel.

EXAMPLE I The effect of the basicity of the carrier material on the activity and selectivity of the catalyst according to the invention is demonstrated by this example.

A series of Pt/Al O catalysts with a varying sodium content in the carrier material was tested by passing a highly refined oil fraction which was free of aromatics and of which 97.5% by weight boiled above 375 C., over the individual catalysts together with hydrogen. All catalysts contained 1 part by weight of platinum (metal) to 100 parts by weight of carrier.

The platinum had been deposited on the carrier by impregnating the alumina with an aqueous solution of tetrammineplatinum (II) hydroxide. After impregnation the alumina was dried at 120 C. and calcined in air at 500 C. for 3 hours. After calcination the platinum was reduced to platinum metal by means of hydrogen.

Three alumina carriers with a varying sodium content were examined, namely a commercial alumina with a low sodium content (0.07% by weight), a commercial alumina with a higher sodium content (0.4% by weight) and an alumina obtained by impregnating a commercial alumina with a Na CO -so1ution in order to raise the sodium content (2.4% by Weight).

The reaction conditions employed were as follows: pressure 50 kg./cm. liquid hourly space velocity 1.0 litre of feed per litre of catalyst per hour; H feed ratio 2000 normal litres/litre. The results obtained as well as of the composition and some properties of the feed used are summarized below.

FEED Properties: Cs. Viscosity at 100 F. 74.71 Viscosity at 140 F. 26.6 Viscosity at 210 F. 8.11 Viscosity index 80 Composition: Percent by weight Parafiins 14 Mononaphthenes 27 Dinaphthenes 23 Trinaphthenes 17 Tetranaphthenes 1 1 Pentanaphthenes 4 Hexanaphthenes 1 Balance 3 BASE OIL Carrier material of the catalyst A1203 plus A120; plus A120 plus 2.4% \v. of 0.4% w. of 0.07% w. of Na Na Na Reaction temperature, C 420 385 380 Product boiling above 375 0.: Yield, percent w. based on feed 65. 4 63. 65. 3 Viscosity at 210 F., cs 6. 42 7.08 7. 00 Viscosity index 85 88 89 Saturates in product boiling above 375 0.:

Yield, percent w., based on product bo ng above 375 C 71. 8 88. 9 80. 9 Viscosity at 210 F., cs 6. 25 6. 88 6. 82 Viscosity index 97 94 93 Composition of the saturates,

percent by Weight:

Parailins 22(+8) 28(4-14) 24(+10) Mononaphthenes 20(+2) 32(+5) 28(+1) Dinaplitlieues 21(-2) 17(6) 20(3) Trinaphthenes 15(2) 12(-5) 14(3) Tetranaphthenes 8(3) 7 2-4) 9(2) Pentanaphthenes 4(0) 3 1) 4(0) Hexanaphthenes 1( 0) 1( 0) 1( 0) The results obtained show that the viscosity index of the product boiling above 375 C. is improved by at least points as compared with the starting product. On further refining of the resultant product it is found that especially the yield of saturates in the product obtained by using a catalyst with 0.4% by weight of Na in the carrier is high, while the viscosity index of the oil is good.

The table also shows the relative increase or decrease of the various saturated components in relation to the feed used.

EXAMPLE II This example demonstrates the effect of an increase in the platinum content of the catalyst.

Viscosity index of product boiling above 375 C. at

a yield oi 50% by 60% by 70% by weight, weight weight, Platinum content, parts by weight to based based based 100 parts by weight of eairier on feed on feed on feed The results show that at a higher platinum loading of the catalyst, at the same yield of product boiling above 375 C. a higher VI is obtained.

EXAMPLE III This example demonstrates the effect of the pressure on the process according to the invention.

In order to ascertain the effect of the pressure, the pressure was varied in a series of experiments while the temperature was selected in such a manner that the yield of product boiling above 375 C. amounted to approximately 65% by weight, based on the feed. The catalyst used consisted of 2 parts by weight of Pt on 100 parts by weight of A1 0 the carrier material containing 0.4% by weight of sodium. The feed used and the other reaction conditions were the same as reported in Example I. The results obtained are summarized below:

Reaction conditions:

Pressure, kgJcm. 50 75 100 200 'Iemperature, C 375 375 400 400 Product boiling above 375 0.:

Yield, percent w. based on feed 65. 8 67. 2 64. 9 67.5 Viscosity at 210 F., cs G. 69 6. 78 6. 16 7.38 Viscosity index 90 89 88 Saturates in product boiling above 375 Yield, percent w. based on product boiling above 375 C 88 8 93. 0 02. 5 96. 2 Viscosity at 210 F., 05.... 6. 41 6. 35 7.13 Viscosity index 96 04 88 From the results shown it is found that a pressure of 50 to 75 kg./cm. is an optimum pressure. The optimum effect of the pressure is especially apparent from the saturated compounds in the product boiling above 375 C. Although the yield of saturates in this product increases at the higher pressures used, the viscosity index drops sharply which is indicative of a diminishing dehydrogenation of naphthenes in addition to a reduced opening of the ring.

EXAMPLE IV This example demonstrates the effect of other metals than platinum.

For purposes of comparison experiments were carried out with rhenium and palladium as active metals. The feed and the other reaction conditions were similar to those of Example I. The results obtained as well as the temperature employed are listed below.

Catalyst composition Sulphur content in feed 50 500 5, 000

Pol/A1203 Res/A1203 Pt/AlzOa Reaction temperature, C 385 410 420 420 11/100 1.9/10 20/ Product boiling above 375 6.; parts by parts by p ts by Yield, percent w. based on wt. wt. wt. v iced 63.0 63.6 59.4 02.1 iscoslty at cs 7.08 6.37 5.71 5.88 Na-content, percent by weight 0. 4 0. 4 0. 4 Viscosity index 88 87 02 90 Saturates in product boiling Reaction temperature, C 420 325 375 ab ve 375 0.; Product boiling above 375 0.: Yield, percent w. based on Yield, percent w. based on feed. 69.1 66. 3 65.8 product boiling above Viscosity at 210 F., cs 6. 53 8.80 0. 69 1O 375 C 88. 9 69. 7 67. 8 70.5

Viscosity index 82 64 91 6. 88 6. 02 5. 51 5.81 saturates in product boiling above Viscosity index St 104 108 109 375 0.: Composition of the saturates,

Y1eld percent w. based on percent by weight;

product boiling above 315 0 48.7 88.8 Parafiins 2s +14 22 +s 25 +11 23(+e) Viscosity at 210 F-, 05 8. 3 6- Mononaphthenes 32(+5) 30( 3) 29( 2) 3l( 4) Viscosity index 8 97 Dinaphthcues 17(-6) 21(2) 20( Triuaphtheges 12(5) 14(3) 13(-4) 12(3) The results given show that the use of Pd or Re as active j Q21? 1 &1; .13;

metal component results in catalysts with a low selectlvrty. Hexanaphthenes 1( 0) EXAMPLE V The eifect of the carrier material used is apparent from this example.

Under otherwise identical conditions as in Example I From h results h It 'f be f that the Of and using the same feed three experiments were carried Sulphur y f base 0115 i hlgh V15 but that the Yield out with Pt catalysts which had different carriers. The P saturates In these base 0115 has p y droplmd-P111111er results Obtained as Well as some properties of the carrier 25 1t can be seen that the use of sulphur decreases the actnvty material used as listed below. of tha catalyst The table also shows the relative mcrease or decrease of the various saturates in relation to the feed used.

Carrier material EXAMPLE VII a ag This example demonstrates the effect of a steam treatb g E ment of the carrier material.

32%,; 3%,; A commercially available alumina with a relatively 0 6" 0 38 high chlorine content (0.28% by weight) was subjected to a steam treatment in order to remove the chlorine. 9x19; 1. 26 18 To the material thus treated which had a chlorine content of 0.03% by weight, 0.4% b weight of sodium was Y Sodium int oduced du ing p epa q g a i h added by impregnation with a Na CO -solution. The imall sgg m deposlted on carrier yimpre nationa ter ca cine 1on0 t e pregnated alumina was used for the preparation of a 40 platinum-containing catalyst (1 part by weight of Pt to CATALYST COMPOSITION 100 parts by weight of carrier) in a conventional manner Carrier material by impregnation with a solution containing a platinum compound. After previous reduction with h dro en the B o 5 Pt-content, parts by Weight to 100 part by finished catalyst obtamed after drying and calcmation was Welght Gamer 1 1 tested under the same reaction conditions by means of ges tio n te peregure, 22 385 380 420 the feed of Example I. The results obtained are listed 1'0 110 01 nga 0V9 .2

Yield, percent w., based on feed 63. 0 63. 4 63. 5 belQW' Viscosity at 210 F., cs 7. 08 6. 47 6. 40

Viscosity index 88 91 82 Satufirfatis1 in produtct boilbing aibove 875; C 50 1e percen w. ass on pro uc boiling above 375 0 8s. 9 87. 3 70. 6 ggggggpgggyg egggeg by N a 410 Viscosity at 210 F-, CS 88 13 20 Product boning gq 6 Viscosity index 100 92 Yield percent w based oii feud 62 Composition of the saturates, percent by viscosity at cs K Weigh Viscosity index. 88

{P g gz i Satnrates in product boiling above 375 0.: Z f 17 8 Yield, percer21h)yy.F based on product boiling above 375 0.- 79.2 Tn'naphthenes 1 12 5 ,f,3i '3 Tetranaphthenes-n 7( 4) Composition of thesattaa'ysti-atn't"its ht" Pentanaphthenes.-. 3( Pal-ailing Y g g +1 Hexanaphthenes m 'gg 'j 26( 1) Dmaphthencs... 19(4) ritnaphtllisgedn 14Egg e ranap enes- 8 The catalyst based on carner material B is found to Icntanaphthenes 4(0) produce the best results both in terms of the viscosity Hexanaphthenes 100) index for the product boiling above 375 C. and in terms of the saturates in this product.

The table also shows the relative increase or decrease 65 The results Obtflmed nst a e that the alumina of the various saturates in relation to the feed used.

EXAMPLE VI treated with stem and subsequently impregnated is also a good carrier material for catalysts according to the invention. A good yield of product boiling above 375 C. is obtained, while the content of saturates therein is high.

The table also shows the relative increase or decrease of the various saturated components in relation to the feed used.

EXAMPLE VIII In this example the feed used is a de-asphalted residual oil. A de-asphalted residual oil, obtained by de-asphalting a short residue of a Middle-East crude oil with propane, was treated with hydrogen in the presence of a molydenum/nickel on alumina catalyst for the hydrogenation of any aromatics present, with simultaneous removal of sulphur and nitrogen compounds, and was subsequently passed with hydrogen over a catalyst according to the invention. The properties of the feed and of the products obtained after the first and second process steps were determined by using the oil obtained after dewaxing sam ples of feed and product with a methylethyl ketone/ toluene mixture. The results obtained as well as the reaction conditions used are tabulated below.

1st process step 2d process step Viscosity index S-contcnt, percent by w ght Total Nconteut, p.p.msaturates in oil boiling above 375 Yield, percent by wt. based on dewaxed oil boiling above 375 C 29. 79.1 62. 7 65. 4 Viscosity at 210 F, cs 10. 5 11. 9 8. 2 5.0 Viscosity index 106 112 127 148 Composition of the saturates, percent by eight:

Parallins 33 22 43 55 Mononaphthcnes 30 35 33 28 Dinaphthenes 10 23 10 Trinaphthenes 11 13 6 4 Tetranaphthenes- 5 5 3 3 Pcntanaphthenes 2 1 I-Iexanaphthen% The above results, which are obtained in a once-through operation, show that it is possible to prepare a base oil with a relatively high content of saturates and a VI of more than 100 by starting from a de-asphalted residual oil with a low content of saturates and a VI of lower than 80. It is even possible to prepare a base oil with a VI of 131 but in this case the yield, based on de-asphalted oil, is correspondingly lower. By subjecting the base oils to further refining (removal of aromatics) lubricating oils can be obtained with a VI of 127 and 148.

The decrease in yield of dewaxed oil boiling above 375 C. is partly attributable to the lighter products boiling below 375 C. which have likewise formed during the hydrogenation of the aromatics.

EXAMPLE IX In this example the feed used was a de-asphalted residual oil which oil had been obtained by de-asphalting a short residue of a Middle-East crude oil with propane. It was treated with hydrogen in the presence of a molybdenum/nickel on alumina catalyst for the hydrogenation of any aromatics present, with simultaneous removal of sulphur and nitrogen compounds, and was subsequently passed with hydrogen over a catalyst according to the invention. The properties of the feed and of the products obtained after the first and second process steps were determined by using the oil obtained after dewaxing samples of feed and product with a methyl-ethyl ketone/ toluene mixture. The results obtained as well as the reaction conditions used are tabulated in the following table:

2d process step 1st process stlep i A1203: Na: Pt

CatalylstJ composition, parts by AlzOszMo:

weig :11.7:3.1 100:0. 4:1. 0

Reaction conditions:

Temperature C 20 20 40 Pressure, kg. cm. 200 50 Liquid hourly space velocity 1.1.- .l1.- 1.0 1.0 Hz/feed, normal litres/litre 2, 000 2, 000

After After Feed 1st step 2d step Dcwaxed oil boiling above 375 0.:

Yicls, percent w., based on deasphalted oil 83. 2 38. 9 31. 4 21. 2 Viscosity at 210 F., cs. 43. 3 12. 5 8. 5 5. 3 4. 2 Viscosity index 76 122 134 S-eontent, percent by wei 2. 5 0.02 Total N-content, p.p.m. 7

Saturates in oil boiling above 375 0.:

Yield, percent by wt. based on dewaxed oil boiling above 375C. Viscosity at 210 F., cs 19. 5 Viscosity index Composition of the saturates, percent by weight:

Parailins Trinaphthenesm Tetranaphthencs.

We claim:

1. A process for the production of lubricating base oils having high viscosity index wherein mononaphthene and polynaphthene rings are opened to produce parafiins and naphthenes having a lower number of condensed rings while retaining substantially the same molecular weight which comprises contacting a parafiinic-naphthenic hydrocarbon oil boiling above 350 C. and having an aromatic content of less than 7% weight carbon in an aromatic structure, a paraffin content of 550% weight, a mononaphthene content of 1050% weight, a high content of condensed ring naphthenes and a sulfur content of 0-5000 p.p.m.w. with hydrogen in the presence of a basic catalyst comprising more than 0.5% weight platinum metal supported on a halogen-free alumina containing not more than 4% weight of an alkali or alkaline earth metal at a hydrogen partial pressure of above about 10 kg./cm. and a temperature of at least 345 C.

2. The process of claim 1 wherein the alkali or alkaline earth metal content of the alumina is from 0.05 to 2.5% weight sodium or potassium and the catalyst contains from 15% weight platinum metal.

3. The process of claim 2 wherein the hydrogen partial pressure is from 50 to 75 kg./cm. and the temperature is from 375-450 C.

4. The process of claim 3 wherein the paraflinicnaphthenic hydrocarbon oil contains less than 5% weight carbon in an aromatic structure and the alkali or alkaline earth metal content of the alumina is from 0.05 to 0.5 weight.

References Cited UNITED STATES PATENTS 2,779,711 l/1957 Goretta 208143 2,944,014 7/ 1960 Holfman 208264 3,142,635 7/1964 Coonradt et a1. 20818 3,331,769 7/1967 Gatsis 208264 3,425,932 2/1969 Surrena et al 208143 3,432,565 3/1969 Kouwenhoven et a1. 208143 2,915,452 12/1959 Fear 20857 3,395,196 7/1968 Heckelsberg 260-683 3,431,198 3/1969 Rausch 208143 HERBERT LEVIN Primary Examiner US. Cl. X.R. 20 8--1 8