CA1113969A - Hydrogenation process of olefin polymers for producing white oils - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A process for hydrogenating polymers which are derived from olefin units containing 4 carbon atoms is disclosed whereby white oils which exhibit a low iodine value (e.g., below 0.26) are obtained under relatively mild reaction conditions. The hydrogenation is effected in the presence of a catalyst comprising a noble metal selected from the group of platinum and palladium on an alumina support exhibiting a total pore volume of at least about 0.25 ml/g wherein if the noble metal is platinum, about 90 to about 98% of the pore volume is provided by pores the mean size of which is less than 100%, and if the noble metal is palladium, about 35 to about 50% of the pore volume is provided by small size pores the mean size of which is less than 300.ANG. ? 50.ANG.
and about 25 to about 35% of the pore volume is provided by large size pores the mean size of which is above 300.ANG. ? 50.ANG. with the mean size of the large size pores being at least 1.5 times the mean size of the small size pores.

Description

~h~ ~ ' This application is a division o~ Canadian application no. 273,972 filed March 15, 1977 for "Hydrogenation Process of Olefin Polymers for Producing White Oils".

BACKGROUND OF THE INVENTION
The present invention relates to a process for hydro genating polymers derived from olefin units having 4 carbon atoms and thereby preparing products which are colorless, odorless, stable to heat and storage and which fulfill the requirements for white oils and medicinal oils.
White oils usually are mineral oils which are prepared by high purification of petroleum fractions boiling in the lubricating oil boiling range. This process usually comprises two steps: a desulfurization followed by hyd~ogenation under very severe~.operating conditions. ~hite oils are allowed to be used in or in contact with food, only if they fulfill the official requirements for foodstuffs. The most widely applied standards are the official'requirements in the U.S. regulations promulgated by the FDA, the German regulations set forth in DAB VII and the British regulations set forth in the s.P. acid test.
It has already been proposed to purify polymers which are prepared from olefin units having 4 carbon atoms, particulaxly polybutenes by means of a hydrogenation process/ in order to obtàin a colorless and substantially odorless polybutene which can be used, for example, as a substitute for natural squalane in cosmetic formulas. However, the product obtained does not come close to fulfilling the white oils requirements. Indeed, the iodine value of the hydrogenated product, which charactexizes the unsaturation degree of the product, is much too high.
German Patent Application No. 2,360,306 teaches the 30 ` hydrogenation of polybutene at a temperature o~ between 150 and 230C and at a pressure of between 15 and 35 atmospheres, in the presence o~ nickel or palladium on kieselguhr, but the iodine value of the hydrogenated product is about 1.

: : , . ,, . . , . : ~

U.S. Patent No. 3,100,808 teaches the hydrogenation of polybutene at a temperature of between 60 and 350C, at a pressure of bet~Jeen 3.5 and 210 kg/cm2 in the presence of nickel, palladium or platinum on an alumina support/ but the iodine value of the hydrogenated product is higher than 1. Such an iodine value is absolutely too high in order for the hydrogenated product to fulfill the white oils requirements.
SUMMARY OF THE INVENTION
It is an object o the present invention to provide a process for producing high quality white oils, especially white oils exhibiting a relatively low iodine value.
It is a further objec~ to provide a hydrogenation process, especially a one step process for producing such white oils from polymers der~ed from olefin units containing 4 carbon atoms.
It is a further object of this invention to provide a process which permits hydrogenation under relatively mild reaction conditions. It is a further object to provide such a process which allows preparation of hydrogenated products, the iodine value of which is less than 0.26.
In order to accomplish the foregoing objects, there has been provided, according to the present invention, a process for hydrogenating a liquid polymer derived from olefin units containing 4 carbon atoms which comprises the step of hydrogenating said pol~mer at a suitabie pressure and temperature, in the presence of a catalyst comprising a noble metal selected from the group of platinum and palladium on an alumina support exhibi~ing a total pore volume of at least about 0.25 ml/g wherein, if the noble metal is platinum, hydrogenation is at a hydrogen pressure of between about 40 and about 120 kg/cm2 and a temperature of between about 200 ~o and about 250C, and about 90 to about 98~ of the pore volume is provided by pores the mean size of which is distributed around a mean size of less than 100A and, if the noble metal i5 palladium, hydrogenation is at a hydrogen pressure of between about 20 and ~$~
about 120 kg/cm2 and a temperature of between about 130 and about 250C, a~d abou~ 35 to a~out 50% of the pore volume is provided by small si~e pores the mean size o~ which is distribu~ed around a m~an size of less than 300A + 50A and about 25 to about 35~ of the pore volume is provided by large size pores the mean size of which is distributed around a mean size of about 300A ~ 50A with the mean size of the large size pores being at least 1.5 times the mean siz~ of the small siz~ pores.
If the noble metal in the catalyst is platinum, the reaction temperature preferably is at least about 200C and the hydrogen pressure is at least about 40 kg/cm2.
The space velocity of the liquid may be between about ~.25 and 4 hr 1 A suitable hydrogen:polymer ratio is between about 250 and 6000 Nl/l. Preferably the reaction is effected undar reaction conditions which are sufficient `to yield a hydro-genated product, the iodine value of which is below U.26.
It is really unexpected that such a low iodine value is achieved under such rela$ively mild conditions. It is well known that until now, in order to obtain low iodine values, a 0 much higher temperature had to be applied. Moreover, such a low iodine value has never been reached by hydrogenating polybutenes in such known hydrogenation processes.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The term "a liquid polymer derived from olefin units containing 4 carbon atoms" not only comprises butene polymers, but also isobutene polymers and ~utene and isobutene copolymers, whereby all these homopolymers and copolymers are liquid or oily products. Such polymers generally ha~e a molecular weight of between about 300 and 2000.
The hydrogenation catalyst of the present invention comprises platinum or palladium on an alumina support. The alumina support must be a support having a total pore volume of a-t least 0.25 ml/g, preferably of about 0.25 to about 2.5, most preferably of about 0.25 to 1 ml/g. If the catalyst comprise.s platinum, the support is a monomodal support wherein about 90 to about 98~ of this total pore volume are provided by pores the general size of which is distributed around a mean pore size lower than 100~. Generally the pore size is between about 50 and about 90A~
The mean pore sizes and the recommended percentages of pores within these size ranges are dependent upon each other and are essential operating conditions, and if either of these conditions is not met, the resulting produc~ does not fulfill the white oils requirements as is shown in the comparative examples below.
The amount of platinum which is present in the catalyst is generally between about 0.1 and about 1.0% by weight and, more particularly, between about 0.3 and about 0.7% by weight, based on the total weight of the catalyst.
If the catalyst comprises palladium, the alumina suppoxt must be a bimodul support having a to~al pore volume of at least ...
0.25 ml/g, preferably of about 0.25 to about 2.5, most preferably ~0 of about 0.25 to 1 ml/mg, wherein 35 to 50% of this total volume are provided by small pores the general size of which is distributed around a mean size lower than 300A + 50~ and 25 to 35% of this total volume are provided by large pores the general size of which is distributed around a mean size above 300A 50A, whereby the mean size of the latter is at least about 1.5 times, preferably about l.S to about 5,000 times, the mean size of the former~
The mean pore sizes and the recommended percentages of pores for each size are dependent on each other and are essential operating conditions, and if either of these conditions is not met, the resulting produc-t does not fulfill. the white oil requi.rements, as is shown in the comparative examples below.
Prefera~ly mean si~e of the small pores is between about 30 and about 300A, and particularly between about 50 and about 150A, _ ~ _ hereas that of the larger pores is between 300A - 50A and about 150,000 A, and the mean size of the larger pores always is at least 1.5 times, more particularly between about 10 and 1,000, most preferably between 10 and 200, that of the small pores.
~oreover, the percentage of pore volume which is provided by the small pores must always be a~ least equal to that which is provided by the large pores.
The amount of palladium which is present in the catalyst is generally between about 0.25 and about 1.5% by weight, and more particularly between about 0.4 and about 0.9% by weight, based on the total catalyst weight.
The catalyst composition which is used according to the present invention may be prepared according to conventional impregnation techniques. ~ypically, the support material is impregnated with an aqueous solution of a soluble noble metal compound. The soluble compound is used as a precursor of the metal itself and the desired metal is iormed on the support by a chemical or a thermal treatment of the impregnated support material.
The impregnation may al50 be carried out by other conventional processes according to which the support particles are impregnated with, immersed, or suspended in, or otherwise introduced into an impregnation solution in order to absorb a soluble noble metal compound. On the other hand, the catalyst may be shaped in various forms and particulaxly in the form of granules, extrudates, cylinders, particles, beads or powder. The hydrogenation process according to the present invention may be carried out by using any catalytic hydrogenation technique, e.g., batchwise or in a continuous process and in the latter case, either a fixed bed, or a moving bed or a ~luidized bed procedure may be used.
The reaction temperature and pressure at which the hydrogenation process is carried out, are dependent on each other and the above-defined ranges should be observed. Moreover, it is well known that the higher the temperature and the pressure are, " 1-.
, , ..... . :

~3~
,he more complete the hydrogenation is, and thus the lower the iodine value of the hydrogenated product. According to the p~ocess of the presen~ invention, poiybutene may be hydrogenated a-t a temperature of between about 130 and about 250C in the presence of a palladium catalyst or at a temperature of between about 200 and about 250C in the presence of a platinum catalys-t in order to obtain a hydrogenated product having an iodine value as low as 0.26 while the appl ed pressure is not very high, this pressure being about 75 kg/cm . On the other hand, a hydrogenated product having a very low iodine value may be obtained with a pressure as low as 20 kg/cm2 at a temperature which does not exceed 250C.
Naturally, the temperature and the hydrogen pressure depend on the kind o~ starting material and the type of catalyst which is used.
Usually the temperature is between about 200 and about 250C in case of a platinum catalyst and between about 130 and about 250C in case of a palladium catalyst, and the pressure is between about 40 and about 120 kg/cm2 in case of a platinum catalyst and between about 20 and about 120 kg/cm2 in case of a palladium catalyst. Both these variables can be selected in order to obtain a hydrogenated product having an iodine value lower than or equal to 0.26. Such temperature and pressure conditions are consider-ably milder than those which are used in conventional processes ~or obtaining white oils wherein the pressure must be at least 130 kg/cm2.
~he other operating conditions such as the hourly space velocity of tha liquid and the hydrogen:polymer ratio also have an influence on the iodine value and therefore on the degree of hydrogenation of the resulting product, but this influence is not so important as that due to temperature or pressure. Generally the space velocity of the liquid is between about 0.25 and about 4 hr 1 and particularly between about 0.5 and about 2 hr . The hydrpgen:
polymer ratio usually varies between about 250 and about 6000 Nl/l*
and still higher ratios may be used, but without any significant *(li-ter per liter under normal conditions, i.e., 0C and atmospheric pressure) 6 , ~dvantage.
The obtained hydrogenated products have been submitted to "BP acid test", DAB VI~ test and F.D.~. tests in order to determine their usefulness as white oils and medicinal oils.
According to the ~AB VII requirements, the product must be tested for the absorption of ultraviolet light at 275, 295 and 300 nanometers, in a cell of 1 cm size. The maximum of absorption at each wavelength must be lower than 1.6, 0.2, and 0.15, respectively.
The "BP acid test" consists oE a colorimetric deter-mination of carbonizable matters in a liquid paraffins using an extraction with sulfuric acid. The colorimetric indices according to the Lovibond scale which may not be ~xceeded are 2.5 in the red r~nge and 6.5 in the yellow range, when the eXperimentS are performed in a cell of 10 mm size.
The F.D.A. tes~ consists of three tests, the first of which concerns the determination of the carbonizable matters according to a colorimetric method. The colorimetric indices according to the Lovibond scale which may not be exceeded are 2.1 in the red range and 9 in the yellow range. The second test concerns the analysis of the sulfurized products and the third consists ~f the determination of the absorbance of ultraviolet light of the ;;;
extract with D.U.SØ of the test product, whereby this absorbance must not exceed 0.1 at wavelengths of between 260 and 350 nanometers when the experiment is performed in a cell of l cm size.
The following examples are given in order to bettex illustrate the features and advan-tages of the present invention but without limitin~ it.
Example l A hydrogenation catalyst the support of which consists of alumina beads having a diameter 1~5 mmt iS prepared. The specific surface is 209 m /g. The total pore volume is 0.51 ml/g, and 0.5Q ml/g, or 98% of this total pore volume is provided by . - - -: . . . .. . , . . . . " .. , .. ..... .. ., .. -- .
;......... .

~3~
o _,ores the size of which is distributed around a rnean size oE 65A.
100 g of the hereabove described alumina support is dried at 120C and then impregnated with 100 ml of an aqueous solution of chloroplatinic acid con~aining 3 g of chloroplatinic acid. After 1 hour of impregnation, the catalyst is placed on a buchner funnel in order to quickly eliminate ~he excess of the impregnating solution. The wet catalyst is -~hen dried at 120C.
Thereafter, the catalyst is calcined at the air at 500C
and reduced with hydrogen a~ 500C. The reduced catalyst contains 0~59~ by wèight of platinum.
With this catalyst, the continuous hydrogenation of a polybutene the characteristics of which are given in Table I i' below, is performed.
T A B L E
Characteristic Method of determination .. . . .
Specific gravity 15/4C ASTM D 1298 0.838 - v~ScOSity at 37.8C (Cstokes) ASTM D 445 27.34 at 98.9C (Cstokes) ASTM D 445 4.88 ~0 at 37.8C (SSU) 127 Viscosity index ASTM D 2270 110-111 Molecular weight 650 Saybolt color ASTM D 156 ~18 Iodine value IP 84 128~3 The operating conditions under which the hydxogenation is perfonmed, and the properties of the hydrogenated product obtained in each experiment, are indicated in Table II below.
By way of comparison, hydrogenation of a polybutene the characteristics of which are described in Table I, is carried out in the presence of catalysts wherein the support of which or the metal which is deposited thereon is outsicle the scope oE the present invention.
In a comparative experiment A, the support of the catalyst .3~ ~
consists of alumina beads of 1.5 mm diameter, having a total pore volume of 0.87 ml/g and wherein O.58 ml/g, or 67% of this pore volume, is provided by pores the size of which is distributed around a mean size of 200A. Platinum is deposited on this support according to a known process and the final catalyst contains 0.78%
by weight of platinumO
In a comparative experiment B, the support of the catal~st consists of alumina granules having a total pore volume is 0.40 ml/g and wherein 0.25 ml/g, or 62% of this pore volume is provided by pores thè size of which is distributed around a mean size of 60A.
Palladium is deposited on this support according to a known process, and the final catalyst contains 0.55~ by weight of palladium.
~ n a comparative experiment C, a catalyst is tested the suppoxt of which.consists of alumina granules having a total pore volume of 0.58 ml/g and wherein 0.53 ml/g, or 91% of thîs pore volume, is provided by pores the size of which is distributed around a mean size of 55A. Palladium is deposited on this support according to a known process and the final catalyst contains 0.6% :~
by weight of palladium.
In a comparative experiment D, the hydrogenation is carried out in the presence of 10% by weight of black palladium.
The operating conditions under which the comparative experiments A, B, C and D are carried out and the properties of the resulting hydrogenated products are indicated in Table II `~
below.

_ 9 _ T A B L E I I
Characteristic Experiment 1* 2* A B C D
Temperature (C) 230 200 200 230 230 200 Li~uid Space velocity(hr Pressure~kg/cm ~ 100 75 75 100 100 75 Hydrogen: Polymer ra~iotNl/l) 300 300 300 300 300 300 10 Specific gravity 15~DsC . 0.838 0.838~0.83~ Q.8380083~0.838 Viscosity . r at 37.8C(Cstokes~27. 34 27. 34 27. 34 27.34 27.34 27. 34 at 98.9~CtCstokes)4.88 4.88 4.884.88 4.g8 4.88 at 37.8C(SSU) 127 127 127 127 127 127 Viscosity Inde~ 110-111 110-111 110~ 110-111. 110-111 110-111 Saybolt color ~30 ~30 +30 ~30 ~30 ~Z7 Iodine value 0.12 0.26 0O78 3.5 1.8 10 BP acid test conorm conform n o t c o n f o r m [1.5R [2.5R
[3.6Y [6.5Y
D~B VII - UV absorption cell.lcm 275 nm ~.05 0.12 0.15 0.5 0.2 not co~form 295 nm 0.01 0Ø2 Q.~3 0.~7 a .. ~5 30Q nm a.ol 0.Ql Q.Q2 . Q.04 Q.Q3 FDA
-sulfuri~ed compounds c o n ~ a r m -polynuclear aroma tics cell 1 cm 260 - 350 nm c o n ~ o r m -USP acid test c o n f o r m n o t c o n ~ o r m ~1.4R ~2.1R
~3.6Y [8.5Y
Odor o d o r 1 e s ~ u n s a t i s ~ a c t o r y 1~ yellow range, ~=red range]:
Example 2 .
The process descri~ed în Example l.is repeated in order to obtain a catalyst containing 0.64% ~y weight o platinum on a support consisting o alumina beads having a total pore volume o~
0.53 ml/g and wherein 0.49 ml/g or 92% of this pore volume is provided by pores the size of wh.ich is distributed around a mean * catalyst in both experiments as described in Example 1~

size of 70A.
With this catalyst, the hydrogenation of polybutene, thP characteristics of which axe given in Table III below, is ca~ried out.

T A B L E I I I
Characteristic Determination method _.
Specific gxavity 15/4C AST~ D. 1248 0.831 Viscosity a~ 98.9C (SSU) 1067 Iodine value IP 84* 60 10 Saybolt color ASTM D. lS6 + 18 The operating conditions under which the hydroyenation r iS carried out and the properties of the resulting hydrogenated product are indicated in Table IV below.
* IP = Institute of Petroleum method.
~ T A B L E I V
Temperature - . 240C
Pressure 115 k ~cm2 Liquid hourly space velocity 1 hr 1 - Hydrogen: Pol~mer ratio 500 Nl/l Iodine value 0.16 Saybolt color +30 BP acid test conform ~1.6R
f4.1Y

D~B VII - W absorption Cell 1 cm 275 nm O.Q5 295 nm 0.01 300 nm - 0.01 FDA
-Sulfurized compounds conform -Polynuclear aromatics cell 1 cm - 260-350 nm con~orm - Example 3 . The cataIyst described in Example 1 is used to hydrogenate a polybutene, the characteristics of which are indicated in Table III of Example 2. The hydrogenation is carried ~ut unaer the following opera~ing conditions:
Temperature 230C
Pressure 100 kg/cm2 Liquid hourly space velocity 2 hr 1 Hydrogen: Polymer ratio 5000 Nl/l The properties of the resulting hydrogenated product are the ~ollowing: . ;
Saybolt color + 30 Iodine value . 0.20 10 BP acid tes~ conform ~1.7R
[4.2Y

DAB VII - W abs~rptio~
cell 1 cm 275 nm 0.1 295 nm `- 0.~2 300 nm 0.01 FDA
-Sulfurized compounds conform -polynuclear aromatics cell 1 cm - 260-350 nm conform -USP acid test con~orm [1.9R
[6.5Y
Odor ~ . Odorless Example 4 According to the process described in Example 1 there i~.preparea a catalyst containing 0.44~ by weight of platinum on the same support as that described in Exampla 1 and co~sisking of alumina beads having a total pore volume of 0.51 ml~g wherein 0.50 ml/g or 98~ of this total pore volume is provided ~y pores the size o which is distributed around a mean size of 65A.
With this catalyst, hydrogenation of the polybutene the characteristics of which are described in Table I of Example 1, is carried out under the ~ollowing operating conditions:
Temperature 230C

Pressure50 kg/cm Liquid hourly space velocity 0.5 hr 1 Hydrogen5000 Nl/l The properties of the resulting hydrogenated product ?~
are the following:
Saybolt color ~30 Iodine value 0.24 "BP acid test" conform r2.2R
[6.5y DAB VII - W absorption cell 1 cm 275 nm 0.12 295 nm 0.02 300 nm a . ol FDA
-Sulfurized compounds conform : -Polynuclear aromatics cell 1 cm 260-350 nm conform ~USP acid test conform [2.lR
. :[7.0~
Odor Odorless .
The polybutenes which are hydrogenated according to the ~0 process of the present invention, are characterized by a remarkable heat and storage stabilityi The product obtained in experiment 1 of Example 1 is heated at ~00C during 48 hours. After these 48 hours of heating, the.product is odorless and has a Saybolt color of ~30. :
~ he product which is obtained in experiment 1 of Example 1 is introduced into a steel vessel.. The vessel is closed and stored at room temperature.
After one week, the product is still odorless and its Saybolt color is ~30.
Example 5 A hydrogenation catalyst the support of whîch consists o~ alumina extrudates having a diameter o~ 1.5 mm, is pxepared.
The specific surface is 174 m2/g. The total pore. volume is 0.81 ml/g. This pore volume has the following distri~ution:
- 0.37 ml/g, or 45.7% of the total pore volume are provided by small pores, the size of which is distri~uted around a mean size of 65A, 0.25 ml/g, or 30.9% of the total pore volume are provided by large pores the size of which is distributed around ~ 13 -~ ~3~,ft.
o a mean size of 6,000A.
Therea~ter a palladium chlo~ide solution is prepared , by introducing 3.05 g of PdCl2 into 145 g of distilled water and adjusting the pH to l by add.ition of concentrated hydrochloric acid. The mixture is heated to about 60C until the dissolution of the salt is substantially completed and then filtered after cooling. Analysis shows that the solution contains 1.24 g Pd pex lO0 g solution. To 95.31 g solution, distillated ~ater is added to obtain a total weight of 324 g. Thereafter this solution is poured on 162 g of alumina support which is previously calcineaat 500C and cooled. The mixtu.re is allowed to stand during 16 hours and the solution is decanted. The humid catalyst.is introduced into a store and dried at 120.C. The catalyst is then calcined at the air at sao ~c and reduced with hydrogen at 5~Q~C.
The reduced catalyst contains 0.7% by weiyht of palladium.-With this catalyst, the continuous hydrogenation of abutene polymer the characteristics of which are given in Ta~le V
below, is performed: .
T ~ B ~ E V
20 Characteristic . Met~od o~ deter~n'at~on Speci~ic gravity ls/4oc ASTM D 12~8 0.838 Viscosit~
at 37.8C (C stokesl ASTM D 445 27.34 ' at 98.8C CC stokesl ASTM D 445 4.88 at 37.8C (SSU) . 1~7 Viscosity Index ASTM D 227Q llQ-lll Molecular weight ' 65Q
Saybolt color . ASTM D 156 ~18 Iodine value IP 84 128~3 'The operating cond.~tions under w.hich the hydrogenation is performed and the properties of the hydrogenaked product obtained in each experiment are indicated in Tahle VI herein~elow.

T A B L E V I

Characteristics Experiments 5.1 5.2 5.35.4 5.55.6 Temperature (C) 130 240 178156 178230 Liquid hourly1space velocity (hr Pressure (kg/cm2) 75 75 75 50 75 35 Hydrogen:polvmer ratio ~Nl/l~ 300 300 300 30050005000 Specific gravity 15/4C0.838 0.838 0.838 0.838 0.838 0.838 Viscosity at 37.8C (C stokes)27.34 27.34 27~3427.3427.34 27.34 at 98.9C (C stokes) 4.88 4.88 4.88 4.884.88 4.88 at 37.8C (SSU) 127 127 127 127 127 127 Viscosity Index 110/111 110/111 110/111 110flll 110/111 110/111 :
Saybolt color ~30 ~+30 ~+30 ~+30 ~ 30 ~+30 `~
Iodine value 0.14 0.06 0.08 0.24 0.07 0.26 "BP acid test" conform conform conform conform conform conform 1.7R 0.6R 0.9R 2.2R0.9R2.5R
4.0Y 1.3Y 2.1Y 6.5Y2.1Y6.5Y
DAB VII - W absorption Cell 1 cm 275 nm0.050.04 0.04 0.080.040.14 295 nm0.010.01 0.01 0.020.010.02 300 nm0.010.01 0.01 0.010.010.01 FDA
Sulfurized compound conform conform conform conform conform conform Polynuclear aromatics Cell 1 cm 260/350 nm conform conform conform conform conform conform :
USP acid test conform conform conform conform conform conform 1.6R 0.5R 0.8R 2~0R 0.8R2.1R
4.0Y 1.3Y 2.0Y 6.5Y 2.0Y8~5Y
Odor o d o r 1 e s s Y = Yellow range of the I.ovibond scale.
R = Red range of the Lovibond scale.

~r 3¢~
By way of comparison, hydrogenation of a polybutene the characteristics of which are described in Table v, is per~ormed with catalysts wherein the support on which the metal is deposi~ed iS outside the scope of the present invention.
In a comparative experiment E, the support of the catalyst consists of alumina yranul~s having a total pore volume of 0.39 ml/g, wherein 0.24 ml~g or 61% of that to~al poxe volume is provided by small pores the size o which is distributed around a mean size of 55A. The remainder of the total pore volume is provided by pores the size of which is substantially uniformly distributed ~etween sizes varyLng he~een 1~0 and lO,QQGA.
Palladium is deposited on this support according to a known proce~s and the final catalyst contalns Q.57% by ~eLght of palladium.
In the comparati~Te experiment F, the support of the catalyst consists of kieselguhr on which palla~ium is deposited acçording to a known proces~! and t~e ~inal catalyst contains Q.6%
by weight of palladium.
In the comparat;Ve experLment G, a c~taly~t is tested the support of which cons;sts of alumina granules h~ving a totàl pore volume of 0.77 ml/g, wherein ~.32 ml~s or 42% of t~at total volume i5 provided ~y pores the size of ~h~ch i~ distri~uted around a mean size of 65A and Q.25 ml/y or 32% of that are provided by pores the size of which is distributed around a mean size o~
6,OOOA. Platinum is deposited on this support according to a known process and the final catalyst contains 0..64% by weight of platinum.
The herein~elow Table VII indicates the operat1ng conditions under which the hydrogenation is~performed, and the properties of the hydrogenated product.

L~
T A B L E V I I

Characteristics Comparative Experiment _ _ ' E F G
Temperature (CJ 240 160 180 Liquid hourly Space velocity ~hr ~1 1 1 Pressure ~kg/cm2) 100 17 75 Hydrogen: polymer ratio(N1/1~ 3Qa 3aQ 30Q
Density 15/4C a.838 Q.83~ ~.83 10 Viscosity at 37.8~C ~C stokes~ 27.34 27.34 27.34 at 98.9~C ~C stokes~ 4.88 4.88 4.88 at 37.8C CSSU~ 127 127 127 Viscosity IndexllQ/lll11~/111llQ~110 Saybolt color ~30 ~3Q ~3Q
Iodine value 2.3 l.Q 4.4 "BP acid test" n o t c o n ~ o r m DAB VII-UV ab,sorption cell 1 cm 275 nm 0.30 Q.15 ~.60 295 nm ~.05 0 03 Q 0 300 nm 0.03 0 02 0 04 FDA
Sulfurlzed compounds c o n ~ o x m Polynuclear aromatics cell 1 cm -260-350 nm c o n ~ o r m USP acid test n o t c o n f o r m Odor - u n s a t i s f a c t o r y Example 6 The process which is described in Example 5 is repeated in order to obtain a catalyst containing 0.41% by weight of palladium based on the weight of the catalyst, on a support consisting of alumina granules having a total pore volume of O.32 ml/g wherein 45% of that total pore volume is provided by pores the size of which is distributed around a mean size o~ 125A
and 27.5%, distributed around a mean size of 600A.
In the presence of this cataly.st, a polybutene whose characteristics are described in Table V of Example 5, was hydrogenated under the following operating condi~ions.

...... . . ..

~emperature 160C
Pressure 75 kg/cm Liquid space velocity 2 hr 1 Hydrogen: pol~mer ratio S00 Nl/l ` The hydrogenated product has the follo~ing propertie~:
Saybolt color ~30 Iodine value 0,15 BP acid test conform 1.7R
4.lY
DAB VII - W absorption Cell 1 cm - 275 nm O.Q5 295 nm ~.Ql 300 nm FDA
Sulfurized compounds conorm Polynuclear aromatics Cell 1 cm - 260-350 nm conform - USP acid test con~orm 1.6R .
4.lY
By way of comparison, a catalyst is prepared according to the process described in Example 5, which contains 0.49~ by weight based on the total weight of catalyst, of palladium on an alumina support having a total pore volume of 0.34 ml/g wherein 16% of that total pore volume is provided ~y pores the size o~
which is distributed around a mean size of 3S~ and 74% o that total pore ~olume is provided by pores the size of which is distributed around a mean size of 300A.
In the presence o~ this catalyst, a poly~utene, the characteristics of which are descrihed in Table V o~ Example 5, is hydrogenated under the hereinabove described operating conditions.
The hydrogenated product ha~ the followin~ propsrties:
` Saybolt color ~30 Iodine value 1.2 BP acid test not con~orm DAs VII - uv absorption Cell 1 cm 275 nm 0.18 295 0.03 300 mn 0 . 02 FDA
Sulfurized compounds conform Polynuclear aromatic~ -cell l cm - 260-350 nm conform USP acid test not conform 10 Odor unsatisfactory Example 7 The process de~cribed in Example S is repeàted ln order :
to obtain a catalyst containing Q.q2~ by ~eight hased on the total weight of catalyst, of palladium on an alumina support havin~ a total pore volume of 0.32 ml~g wherein 45% o~ that total pore volume is provided ~y pores the size of ~hich is dlstributed around a mean size of 125A and 27.5% o~ that total pore volume is provided by pores the size of which is distri~uted around a mean .
size of 600A.
In t~e presence o~ thi5 catal~st, a poly~uten~ the characteristics of which are descrihed în Table V o~ Example 5, is hydrogenated under thR following operating conditions:
Temperature 2QQC
P.ressure 75 k~/cm2 Liquid-Space velocity -l !
Hydrogen:polymer ratio 5~Q Nl~l The hydrogenated product ~a~ the ~ollo~ing ~xopert;es:
Saybolt color ~3Q
Iodine value Q.~8 30 BP acid test con~orm a . 9R

2.1Y
DAB VII - UV absorption Cell l cm 275.nm 0.04 295 nm 0.01 300 nm 0.01 . .

FDA
Sulfurize~ compounds conform Polynuclear aromatics Cell 1 cm 260-350 nm con~orm USP acid test conform 0.8R
2~0Y
Odor Odorless While the invention has now been described in texms of certain preferred embodiments, and exemplîfied with respect ther~to, the skilled artisan ~îll appreciate that various modifications, changes, su~stitutions, and omissions ma~ ~e made without dèparting fro~ the spirit thereof~ ~ccordingly, it is intended that the scope of the present invention ~e limîted solely by that of the follo~ing claim~.

~ 2a -

Claims (12)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for hydrogenating a liquid polymer derived from olefin units containing four carbon atoms, which comprises the step of hydrogenating said polymer at a hydrogen pressure between about 40 and about 120 kg/cm2 and at a temperature of between about 200 and about 250°C
in the presence of a catalyst comprising platinum on an alumina support, exhibiting a total pore volume of at least about 0.25 ml/g wherein about 90 to about 98%
of the pore volume is provided by pores the sizes of Which are distributed around a mean size of less than 100 .ANG..

2. The process as defined in Claim 1, wherein the space velocity of the liquid is between about 0.25 and 4 hr-1.

3. The process as defined in Claim 1, wherein the hydrogen:polymer ratio is between about 250 and 6000 Nl/l.

4. The process as defined in Claim 1, wherein the total pore volume of the alumina support is from about 0.25 ml/g to about 2.5 ml/g.

5. The process as defined in Claim 1, wherein the polymers are selected from the group consisting of butene polymers, isobutene polymers and copolymers of butene and isobutene.

6. The process as defined in Claim 5, wherein the molecular weight of the polymer is between about 300 and about 2000.

7. The process as defined in Claim 1, wherein the catalyst contains between about 0.1 and about 1.0 %
by weight of platinum.

8. The process as defined in Claim 7, wherein the catalyst contains between about 0.3 and about 0.7 by weight of platinum.

9. The process as defined in Claim 1, wherein the catalyst support comprises mono-modul alumina wherein the pore size is distributed around the mean size of between about 50 and about 90 .ANG..

10. The process as defined in Claim 1, wherein the shape of catalyst support is selected from the group consisting of extrudate, cylinders and beads.

11. The process as defined in Claim 1, wherein the catalyst support is a powder.

12. The process as defined in Claim 1, wherein the catalyst is a granulate.