WO2014033738A2

WO2014033738A2 - Process for preparation of a solid oligomerization catalyst and applications thereof

Info

Publication number: WO2014033738A2
Application number: PCT/IN2013/000439
Authority: WO
Inventors: Saptarshi Ray; Sudha Tyagi; Poyyamani Swaminathan Viswanathan
Original assignee: Bharat Petroleum Corp Ltd
Current assignee: Bharat Petroleum Corp Ltd
Priority date: 2012-07-17
Filing date: 2013-07-16
Publication date: 2014-03-06
Anticipated expiration: 2015-01-17
Also published as: WO2014033738A3

Description

PROCESS FOR PREPARATION OF A SOLD3 OLIGOMERIZATION

CATALYST AND APPLICATIONS THEREOF

TECHNICAL FIELD

[0001] The present disclosure relates to a process for preparation of a solid oligomerization catalyst.

[0002] The present disclosure also relates to a process for oligomerization of olefins using the solid oligomerization catalyst. The oligomerized product obtained by the process of the present disclosure has improved properties like viscosity, viscosity index and pour point.

BACKGROUND

[0003] Aluminium chloride (AlC ) acts as a catalyst for 1 -olefin polymerization and is generally used along with a co-activator like water, or various alcohols. The co- activator produces the active intermediate along with the liberation of hydrogen chloride which facilitates the oligomerization process.

[0004] US 2006/0161034 discloses a diluent free oligomerization of a combination of 1 -olefins by using a mixture of AICI3 and deionised water in a continuous process.

[0005] US 5,451 ,704 discloses silica supported EtAlCl₂ as a catalyst for polymerization of l-decene with H₂0 as the co-initiator. It is reported that the molecular weights (number average and weight average) of the polyalphaolefins (PAOs) obtained from the silica supported AICI3 and unsupported AICI3 catalysts are similar, although the molecular wejgh^isfrjbutipn_. pf_the_ polyalphaolefins (PAOs) obtained from the heterogeneous catalysts is slightly broader when compared to those obtained from the homogeneous catalysts. This is expected, since AICI3 is not soluble in l-decene and as such it should act like a heterogeneous catalyst.

[0006] US 6,096,678 discloses a process for the preparation of an inert oxide supported metal halide organo aluminium compound catalyst. The catalyst is obtained by reacting an activated support having surface hydroxyl groups with aluminium chloride selected from aluminium chloride solution and aluminium chloride vapors. [0007] US 6,002,060 discloses silica supported mixture of A1C1₃ and EtAlCl₂, and their subsequent use for polymerization of 1-decene, respectively. Oligomerization of 1 -decene produced base stocks of viscosity index in the range of 138-140.

[0008] The treatment of silica with various peroxides, for example hydrogen peroxide to enhance its free hydroxyl content on the surface is known in the art. Pre- treatment of silica using 35% hydrogen peroxide removes contaminants and activates surface silaonol groups (Park et. al, Reactive & Functional Polymers, 2002, 5/, 79- 92).

[0009] None of the known documents discloses a solid catalyst or a process for making a solid catalyst for oligomerization of alpha olefins. Thus, there is a need for a solid catalyst and a process to obtain a solid catalyst for oligomerization of alpha olefins.

SUMMARY

[00010] The present disclosure relates to a process for preparation of a solid oligomerization catalyst, comprising: treating a catalyst carrier with an activating agent to obtain an activated catalyst carrier, wherein the catalyst carrier is an oxide of an element selected from the group consisting of group III, group IV of the periodic table and mixtures thereof; reacting the activated catalyst carrier with a metal trihalide catalyst in a hydrocarbon solvent to obtain a reaction mixture, wherein the metal trihalide catalyst contains a metal of group III of the periodic table; and removing the hydrocarbon solvent from the reaction mixture to obtain a solid oligomerization catalyst.

[00011] The present disclosure also relates to a process for oligomerization of olefins, comprising: mixing at least one monomer and a solid oligomerization catalyst to obtain a reaction mixture; and stirring the reaction mixture for a time period in the range of 90 to 120 minutes at a temperature in the range of 70 deg C to 100 deg C to obtain an oligomeric olefinic product.

[00012] The present disclosure further relates to a process for oligomerization of olefins, comprising: mixing at least one monomer and a solid oligomerization catalyst to obtain a reaction mixture; adding a hydrocarbon diluent to the reaction mixture to obtain a diluted reaction mixture, wherein the hydrocarbon diluent is selected from the group consisting of heptane, octane, decane, cyclohexane, light naphtha, heavy naphtha and mixtures thereof; and stirring the diluted reaction mixture for a time period in the range of 90 to 120 minutes at a temperature in the range of 70 deg C to 100 deg C to obtain an oligomeric olefinic product.

[00013] These and other features, aspects, and advantages of the present subject matter will become better understood with reference to the following description. This summary is not intended to identify key features or essential features of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWING

[00014] The above and other features, aspects, and advantages of the subject matter will become better understood with regard to the following description, appended claims, and accompanying drawings where:

[00015] Figure 1 illustrates an apparatus for the measurement of surface hydroxyl of silica.

DETAILED DESCRIPTION

[00016] The present invention now will be described more fully hereinafter. Indeed, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. As used in the specification, and in the appended claims, the singular forms "a", "an", "the", include plural referents unless the context clearlv-dictates otherwise. -

[00017] The present disclosure relates to a process for preparation of a solid oligomerization catalyst. The solid oligomerization catalyst obtained by the process of the present disclosure does not need any co-initiator for the oligomerization process. The solid oligomerisation catalyst acts as a co-initiator. The increase of the free hydroxyl group on silica surface acts as proton donor and therefore extra co-initiator is not required.

[00018] The present disclosure provides a process for preparation of a solid oligomerization catalyst, comprising: treating a catalyst carrier with an activating agent to obtain an activated catalyst carrier, wherein the catalyst carrier is an oxide of an element selected from the group consisting of group III, group IV of the periodic table and mixtures thereof; reacting the activated catalyst carrier with a metal trihaiide catalyst in a hydrocarbon solvent to obtain a reaction mixture, wherein the metal trihaiide catalyst contains a metal of group III of the periodic table; and removing the hydrocarbon solvent from the reaction mixture to obtain a solid oligomerization catalyst. The activating agent of the present disclosure is used to enhance free hydroxyl content on the surface of the catalyst carrier.

[00019] The solid oligomerization catalyst is washed with a hydrocarbon solvent to remove unreacted compounds, followed by drying.

[00020] An embodiment of the present disclosure provides a process for preparation of a solid oligomerization catalyst, comprising: treating a catalyst carrier with an activating agent to obtain an activated catalyst carrier, wherein the catalyst carrier is an oxide of an element selected from the group consisting of group III, group IV element of the periodic table and mixtures thereof; refluxing the activated catalyst carrier with a metal trihaiide catalyst in a hydrocarbon solvent at a temperature in the range of 120 deg C to 140 deg C for a time period in the range of 10 to 17 hours, to obtain a reaction mixture; and removing the hydrocarbon solvent from the reaction mixture to obtain a solid oligomerization catalyst. The solid oligomerization catalyst is washed with a hydrocarbon solvent to remove unreacted compounds, followed by drying.

[00021] Still another embodiment of the present disclosure provides a process for preparation of a solid oligomerization catalyst, comprising: treating a catalyst carrier with an activating agent to_obtain_an_acti.vated catalyst carrier, wherein the catalyst carrier is an oxide of an element selected from the group consisting of group III, group IV of the periodic table and mixtures thereof; refluxing the activated catalyst carrier with a metal trihaiide catalyst in a hydrocarbon solvent at a temperature of 120 deg C for 10 hours, to obtain a reaction mixture; and removing the hydrocarbon solvent from the reaction mixture to obtain solid oligomerization catalyst.

[00022] The catalyst carrier used in the present disclosure is selected from the group consisting of silica, alumina, and mixtures thereof. The catalyst carrier used in the present disclosure is preferably silica gel. The silica gel used in the process of the present disclosure is prepared by hydrolysis of a suitable silyl precursor, for example tetraethyl orthosilicate, and subsequent calcinations.

[00023] In the process of the present disclosure the catalyst carrier is washed with a dilute mineral acid before treating with an activating agent and optionally washed with a dilute mineral acid after treating with an activating agent. The mineral acid used in the process of the present disclosure is a strong inorganic acid. The non- limiting examples of mineral acid used in accordance with the present disclosure is selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, nitrous acid and mixtures thereof.

[00024] Silica gel is washed with a dilute mineral acid, followed by washing with copious amount of de-ionized water. This was then followed by treatment with hydrogen peroxide and again washing with de-ionized water. The washed silica is then dried in the temperature range 100 deg C to 160 deg C for 15 to 20 hours. The resulting mixture is then refluxed in dry toluene for 2 hours under nitrogen blanket and then aluminum chloride is added into the refluxing mixture. The refluxing is then continued for further 15 hours and then washed with copious amount of dry toluene. The solid was dried under vacuum to remove any volatile material and preserved under nitrogen blanket.

[00025] The specific surface area of the catalyst carrier used in the present disclosure is in the range of 250m²/g to 400m²/g. The accessibility of the hydroxyl groups of the catalyst carrier to metal trihalides increases with an increase in the surface area of the catalyst carrier.

[00026] The activated catalyst carrier is dried_at_a temperature i the range of 100 deg C to 160 deg C for a time period in the range of 15 to 20 hours before reacting with the trihalide catalyst. The activated catalyst carrier is dried at a temperature in the range of 105 deg C to 1 15 deg C for a time period in the range of 16 to 18 hours before reacting with the trihalide catalyst.

[00027] The activating agent which enhances free hydroxyl content on the surface of the catalyst carrier in the process of the present disclosure is selected from the group consisting of inorganic peroxide, organic peroxide and mixtures thereof. The inorganic peroxide used in the present disclosure is hydrogen peroxide. The organic peroxide used in the present disclosure is selected from the group consisting of benzoyl peroxide, diethyl ether peroxide, tertiary butyl peroxide, tertiary butyl hydroperoxide and mixtures thereof.

[00028] The metal trihalide catalyst contains a metal of group III of the periodic table and selected from the group consisting of aluminium trichloride, aluminium tribromide, aluminium triiodide and mixtures thereof. The trihalide catalyst used in the process of the present disclosure is preferably aluminium trichloride.

[00029] The hydrocarbon solvent used in the process of the present disclosure is selected from the group consisting of aromatic hydrocarbon solvent, aliphatic hydrocarbon solvent and mixtures thereof. The aromatic hydrocarbon solvent used in the present disclosure is selected from the group consisting of toluene, ethylbenzene, ortho-xylene, meta-xylene, para-xylene, l-ethyl-2-methylbenzene, l -ethyl-3- methylbenzene, l-ethyl-4-methylbenzene, cumene, 1,2,3-trimethylbenzene, 1,2,4- trimethylbenzene, l -methyl-3-isopropylbenzene, naphthalene, decahydronaphthalene and mixtures thereof. Further, the aliphatic hydrocarbon solvent used in the present disclosure is selected from the group consisting of octane, decane, dodacane and cyclohexane.

[00030] The process for preparation of a solid oligomerization catalyst of the present disclosure is carried out in an inert atmosphere, preferably nitrogen or argon atmosphere.

[00031] Further an embodiment of the present disclosure provides a process for preparation of a solid oligomerization catalyst, comprising: treating silica with hydrogen peroxide to obtain an activated silica; refluxing the activated silica with aluminium chloride ^ m toluene_ aLaJ:emp.erature-of-120-deg -C for- 10 hours to obtain a reaction mixture; and removing toluene from the reaction mixture to obtain solid oligomerization catalyst.

[00032] The solid oligomerization catalyst is washed with toluene to remove unreacted compounds, followed by drying.

[00033] The catalyst obtained by the process of the present disclosure does not need any co-initiator during the oligomerization process. In other words, the process of oligomerization of olefin using the solid catalyst obtained by the process of the present disclosure involves a single component catalytic system. [00034] The present disclosure also provides a process for oligomerization of olefins, comprising: mixing at least one monomer and a solid oligomerization catalyst to obtain a reaction mixture; and stirring the reaction mixture for a time period in the range of 90 to 120 minutes at a temperature in the range of 70 deg C to 100 deg C to obtain an oligomeric oiefinic product; wherein the solid oligomerization catalyst is prepared by treating a catalyst carrier with an activating agent to obtain an activated catalyst carrier, wherein the catalyst carrier is an oxide of an element selected from the group consisting of group III, group IV of the periodic table and mixtures thereof; reacting the activated catalyst carrier with a metal trihalide catalyst in a hydrocarbon solvent to obtain a reaction mixture, wherein the metal trihalide catalyst contains a metal of group III of the periodic table; and removing the hydrocarbon solvent from the reaction mixture to obtain the solid oligomerization catalyst.

[00035J The present disclosure further provides a process for oligomerization of olefins, comprising: mixing at least one monomer and a solid oligomerization catalyst to obtain a reaction mixture; adding a hydrocarbon diluent to the reaction mixture to obtain a diluted reaction mixture; wherein the hydrocarbon diluent is selected from the group consisting of heptane, octane, decane, cyclohexane, light naphtha, heavy naphtha, and mixtures thereof and stirring the diluted reaction mixture for a time period in the range of 90 to 120 minutes at a temperature in the range of 70 deg C to 100 deg C to obtain an oligomeric oiefinic product; wherein the solid oligomerization catalyst is prepared by treating a catalyst carrier with an activating agent to obtain an activated catalyst carrier, wherein the catalyst carrier is an oxide of an element selected fro the group consisting-of -group- ΙΙΙ,-group IV- of the periodic table and mixtures thereof; reacting the activated catalyst carrier with a metal trihalide catalyst in a hydrocarbon solvent to obtain a reaction mixture, wherein the metal trihalide catalyst contains a metal of group III of the periodic table; and removing the hydrocarbon solvent from the reaction mixture to obtain the solid oligomerization catalyst.

[00036] The monomer used in accordance with the present disclosure is an alpha olefin having general formula C_nH2_n; where n = 6 to 12, is selected from the group consisting of 1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene and mixture thereof. The alpha olefins can be used individually or as a mixture of various alpha olefins.

[00037] The oligomerization of olefins in accordance with the present disclosure can be done either in the presence or in the absence of a hydrocarbon diluent. The catalyst is insoluble both in the liquid alpha olefin monomers used during the oligomerization process, and the hydrocarbon diluent is used optionally. Prior to oligomerization reaction, the liquid monomers should be dried using freshly activated molecular sieves. Activation of molecular sieves can be accomplished by calcining the molecular sieves at 300 deg C under nitrogen flow, for at least 5 hours, followed by cooling to ambient condition under nitrogen. It is also essential that the entire oligomerization reaction be carried out in the absence of air. Accordingly all the oligomerization reactions should be performed under nitrogen blanket.

[00038] The hydrocarbon diluent can be aliphatic in nature, for example heptane, octane, decane, cyclohexane, or various refinery streams like light naphtha, heavy naphtha and mixtures thereof.

[00039] The oligomeric olefinic product obtained by the process of the present disclosure is treated with sodium hydroxide, followed by washing and distillation under reduced pressure to remove unreacted monomer. The recovered monomers can be recycled back to the reaction mixture for further oligomerization.

[00040] The oligomeric olefinic products obtained by the process of the present disclosure contain reactive olefinic end groups. The presence of olefinic end groups generally deteriorates the oxidative stability of resulting oil. it is thus very much essential to hydr genate the olefinic. end. group-B doing so the oxidative stability of the product is enhanced. The hydrogenation of unsaturation can be done using a variety of catalyst for example supported nickel, platinum or palladium. The support can be alumina or carbon etc. Temperature of hydrogenation can be anywhere between 80 deg C to 250 deg C and pressure between 200 to 1000 psi of hydrogen.

[00041] The oligomerization products obtained by the process of the present disclosure are suitable for lubricating application.

EXAMPLES [00042J The disclosure will now be illustrated with working examples, which is intended to illustrate the working of the disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure. Other embodiments are also possible.

Example-1: Preparation of Si0₂ supported aluminium trichloride (AICI₃) catalyst:

[00043] 120 g silica was washed with dilute hydrochloric acid (approx. strength 1 M). It was then stirred, filtered and washed thoroughly with 500 ml of deionized water. The washed silica was then treated with approximately 250 ml of hydrogen peroxide solution of 30% (w/w) concentration. The treated silica was then washed with deionized water for the second time and dried in oven at 100 deg C for 15 hours. The dried silica was then refluxed using dry toluene at 120 deg C in a three necked round bottom flask. The refluxing was continued for 3 hours. Then approx 40 g of aluminum chloride was added to the refluxing mixture and the refluxing was further continued for 10 hours. During the refluxing, a dark purple coloured mixture was formed. The refluxing mixture was then allowed to cool to room temperature and the solid catalyst was allowed to settle. The supernatant solvent containing the unreacted aluminium chloride was siphoned out of the flask under positive pressure of nitrogen and fresh dry toluene was added to the solid catalyst. This was then followed by stirring, settling of the solid catalyst and siphoning of the supernatant solvent. This entire process was then repeated two more times. After the third wash, no aluminium was observed in the supernatant. The solid catalyst thus obtained, was subjected to high vacuum (~ lO^"3 atm) until a free-flowing solid catalyst was obtained.

[00044] The solid catalyst was preserved under nitrogen in a glove box.

[00045] Sample of the solid catalyst thus obtained was then digested in sulphuric acid/nitric acid mixture and the extracted aluminium is estimated using Inductively Coupled Plasma Spectrometer.

ExampIe-2: Preparation of Si0₂ supported aluminium trichloride (A1CI₃) catalyst:

[00046] The solid catalyst was obtained by the process as described in example 1 except silica pretreatment using H₂0₂. Example-3: Prepiaration of S1O2 supported aluminum tri bromide (AlBr₃) catalyst:

[00047] 120 g silica was washed with dilute hydrochloric acid (approx. strength 1 M). It was then stirred, filtered and washed thoroughly with 500 ml of deionized water. The washed silica was then treated with approximately 250 ml of hydrogen peroxide solution of 30% (w/w) concentration. The treated silica was then washed with deionized water for the second time and dried in oven at 180 deg C for 15 hours. The dried silica was then refluxed using dry toluene at 120 deg C in a three necked round bottom flask. The refluxing was continued for 3 hours. Then approx 80 g of aluminum bromide was added to the refluxing mixture and the refluxing was further continued for 10 hours. The refluxing mixture was then allowed to cool to room temperature and the solid catalyst was allowed to settle. The supernatant solvent containing the unreacted aluminium bromide was siphoned out of the flask under positive pressure of nitrogen and fresh dry toluene was added to the solid catalyst. This is then followed by stirring, settling of the solid catalyst and siphoning of the supernatant liquid. This entire process was then repeated two more times. After the third wash, no aluminium was observed in the supernatant. The solid catalyst thus obtained, was subjected to high vacuum (~ l O^"3 atm) until a free-flowing solid catalyst was obtained. The solid catalyst was preserved under nitrogen in a glove box.

[00048] Sample of the solid catalyst thus obtained was then digested in sulphuric acid/nitric acid mixture and the extracted aluminium is estimated using Inductively Coupled Plasma Spectrometer.

__Exampk-4: Preparation of SiOi supported aluminum triiodide (AII₃) catalyst:

[00049] 120 g silica was washed with dilute hydrochloric acid (approx. strength 1M). It was then stirred, filtered and washed thoroughly with 500 ml of deionized water. The washed silica was then treated with approximately 100 ml of benzoyl peroxide solution of 75% (w/w) concentration. The treated silica was then washed with 2M HC1 and with deionized water for the second time and dried in oven at 150 deg C for 20 hours. The dried silica was then refluxed using dry toluene at 120 deg C in a three necked round bottom flask. The refluxing was continued for 3 hours. Then approx 120 g of aluminum iodide was added to the refluxing mixture and the refluxing was further continued for 10 hours. The refluxing mixture was then allowed to cool to room temperature and the solid catalyst was allowed to settle. The supernatant solvent containing the unreacted aluminium iodide is siphoned out of the flask under positive pressure of nitrogen and fresh dry toluene was added to the solid catalyst. This was then followed by stirring, settling of the solid catalyst and siphoning of the supernatant liquid. This entire process was then repeated two more times. After the third wash, no aluminium was observed in the supernatant. The solid catalyst thus obtained, was subjected to high vacuum (~ 10^"3 atm) until a free-flowing solid catalyst was obtained. The solid catalyst was preserved under nitrogen in a glove box.

[00050] Sample of the solid catalyst thus obtained was then digested in sulphuric acid/nitric acid mixture and the extracted aluminium was estimated using Inductively Coupled Plasma Spectrometer.

Example-5: Estimation of surface hydroxyl of silica

[00051] Approximately 500 mg of silica was transferred into a side arm schienk flask containing a magnetic stirring bar, connected to a gas burette via silicon rubber tubing and a rubber septum at the top. The gas burette was filled with silicone oil and consists of a pressure equalizing tube, and was connected to an oil reservoir at the bottom and a three way stopcock at the top of it. The entire setup, including the inside of the schienk flask, the gas burette and the rubber tubing, was provided a nitrogen blanket. Dry heptane was added to the schienk flask. The three way stopcock at the top of the gas burette was opened to the inside of the schienk Flask. The oil level of the gas burette was adjusted to atmospheric pressure with the help of pressure equalizing tube. Approximately 2 ml of methyl magnesium iodide of 2 molar concentration was injected to the schienk flask using a hypodermic syringe. Immediate fall in the gas burette level was observed. The level was again adjusted to the atmospheric pressure and the volume of gas thus evolved was noted.

Table-1: Properties of various silica samples

Aluminum

Surface 2.383 0.597 1.52 3.83 hydroxyls (prior

to addition of

aluminum halide,

mmol/g of silica)

[00052] Surface hydroxyl of silica in Example- 1 is much higher than Example-2, which is expected, since in case of example-2, pre-treatment of silica with hydrogen peroxide is not performed. Surface hydroxyl of silica in Example-3 is also less compared to that in Example- 1, this is because silica is heated at higher temperature after pretreatment. In case of example 4 the surface hydroxyl is highest, probably due to use of a different peroxide and washing with hydrochloric acid for the second time. Percentage aluminium obtained in various catalysts, however does not depend on surface hydroxyl and is more to do with what aluminum halide that is used, for example it is highest when aluminium chloride is used, followed by aluminium bromide and aluminium iodide.

Example-6: Oligomerization of olefin

[00052] Oligomerization of the olefins was done in schlenk flask equipped with nitrogen inlet and outlet, magnetic stirrer and a condenser assembly. The solid catalyst (as prepared in Example 1) was transferred into the flask under nitrogen blanket, preferably inside the glove box. Dry solvent was added to the flask followed by addition of^~5O^_g of dried monomers/monomer blends to the catalyst. Temperature of the reaction mixture was maintained at a 70 deg C to 100 deg C. The reaction mixtures were stirred for 120 minutes. At the end of this the entire mixture were added to sodium hydroxide solution and stirred for 15 min. The mixture was then filtered, which was followed by separation of the product layer from the water layer. The product layer was then dried by addition of sodium sulphate. This was then removed and the product was subjected to mild vacuum in order to remove any solvent followed by high vacuum for the removal of unreacted monomer. [00053] Subsequent to this, the unsaturated oils were hydrogenated using Pd/C catalyst at 250 psi pressure of hydrogen, temperature 80 deg C and time 2 hours. Oligomerization results of various a-olefins using silica supported aluminium chloride catalyst at various conditions are tabulated below in Table 2.

Table-2: Oligomerization results of various -olefins using silica supported aluminium chloride catalyst obtained from Example-1.

Quantity of monomer used per experiment: 50 g

2 Blend: 1:1 :1: 1 mixture of 1-hexene, 1-octene, 1-decene and 1-dodecene by weight. Example-7: Oligomerization of olefin

[00054] Oligomerization of the olefins was done according to the process described Example 6 except that the solid catalyst used is prepared by Example 2. Oligomerization results of various oc-olefins using silica supported aluminum chloride catalysts at various conditions are tabulated below in Table 3. Table-3: Oligomerization results of various a-olefins using silica supported aluminum chloride catalysts obtained from Example-2.

Quantity of monomer used is 50 g.

Example-8: Oligomerization of olefin '

[00055] Oligomerization of the Olefins was done according to the process described in Example 6 and the solid catalyst used is prepared by Example 3. Oligomerization results of various a-olefins using silica supported aluminum bromide at various conditions are tabulated below in Table 3.

Table-3: Oligomerization results of various a-olefins using silica supported aluminum bromide catalyst (example-3).

Quantity of monomer used is 50 g.

ExampIe-9: Oligomerization of olefin [00056] Oligomerization of the olefins was done according to the process described Example 6 and the solid catalyst used is prepared by Example 4. Oligomerization results of various a-olefins using silica supported aluminum iodide catalysts at various conditions are tabulated below in Table 4.

Table-4: Oligomerization results of various α-olefins using silica supported aluminum iodide catalysts (Example-4).

Quantity of monomer used is 50 g.

[00057] Table 5 describes a comparative chart (from Table 1-4) for different - catalyst (prepared by Example 1 -4).

Table 5.

1. Quantity of monomer used is 50 g.

[00058] The catalysts used in example 1, 3, and 4 surprisingly show reduced kinematic viscosity and pour point as compared to the catalyst used in example 2 where pre-treatment of silica with hydrogen peroxide was not performed. Moreover, the catalyst used in example 2 shows lower or same viscosity index as compared to catalysts where pretreatment with activating agent was done.

[00059] In one aspect, Figure 1 illustrates an apparatus for the measurement of surface hydroxyl of silica. In the apparatus 100, according to the present disclosure, a side arm schlenk flask (a) is fitted in a magnetic stirrer (h). The side arm schlenk flask (a) is connected to a gas burette (b) via silicon tube (f) and a rubber septum (g) at the top. The gas burette (b) consists of a pressure equalizing tube (c), and is connected to an oil reservoir (d) at the bottom via a silicone tube (f) and a three way stopcock (e) at the top of it.

[00060] Significant advantage of the present invention is the use of a solid supported catalyst which can be handled more conveniently compared to pure aluminum chloride catalyst. The catalyst can be used in a continuous process, for example fixed bed reactor. Another advantage of the present invention is that the catalyst does not require addition of co-activator, thereby simplifying the process. Further the process disclosed in the present disclosure is cost effective, and is suitable for the production of synthetic base stocks with wide range of properties based on the requirements.

[00061] Although the subject matter has been described in considerable detail with reference to-certai

other embodiments are possible. As such, the spirit and scope of the disclosure should not be limited to the description of the preferred embodiment contained therein.

Claims

I/We Claim:

1. A process for preparation of a solid oligomerization catalyst, comprising:

treating a catalyst carrier with an activating agent to obtain an activated catalyst carrier, wherein the catalyst carrier is an oxide of an element selected from the group consisting of group III, group IV of the periodic table and mixtures thereof;

reacting the activated catalyst carrier with a metal trihalide catalyst in a hydrocarbon solvent to obtain a reaction mixture, wherein the metal trihalide catalyst contains a metal of group III of the periodic table; and

removing the hydrocarbon solvent from the reaction mixture to obtain a solid oligomerization catalyst.

2. The process as claimed in claim 1, wherein the solid oligomerization catalyst is washed with a hydrocarbon solvent to remove unreacted compounds followed by drying.

3. The process as claimed in claim 1 , wherein the catalyst carrier is selected from the group consisting of silica, alumina, and mixtures thereof.

4. The process as claimed in claim 1, wherein the catalyst carrier has specific surface area in the range of 250m²/g to 400m²/g.

_5.__Xhe process as claimejljn_c.laim_l,_wherein the. activating agent is selected from the group consisting of inorganic p.eroxjde,_orRanic-per,oxide-and-mixture thereof.

6. The process as claimed in claim 5, wherein the inorganic peroxide is hydrogen peroxide.

7. The process as claimed in claim 5, wherein the organic peroxide is selected from the group consisting of benzoyl peroxide, diethyl ether peroxide, tertiary butyl peroxide, tertiary butyl hydroperoxide and mixtures thereof.

8. The process as claimed in claim 1, wherein the metal trihalide catalyst is selected from the group consisting of aluminium trichloride, aluminium tribromide, aluminium tri-iodide and mixtures thereof.

9. The process as claimed in claim 1, wherein the hydrocarbon solvent is selected from the group consisting of aromatic hydrocarbon solvent, aliphatic hydrocarbon solvent and mixtures thereof.

10. The process as claimed in claim I, wherein the aromatic hydrocarbon solvent used in the present disclosure is selected from the group consisting of toluene, ethylbenzene, ortho-xylene, meta-xylene, para-xylene, l-ethyl-2- methylbenzene, l-ethyl-3-methylbenzene, l-ethyl-4-methylbenzene, cumene, 1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene, l-methyl-3- isopropylbenzene, naphthalene, decahydronaphthalene and mixtures thereof.

1 1. The process as claimed in claim 1, wherein the the aliphatic hydrocarbon solvent used in the present disclosure is selected from the group consisting of octane, decane, dodacane and cyclohexane.

12. The process as claimed in claim 1, wherein the catalyst carrier is washed with a dilute mineral acid before treating with an activating agent and optionally washed with a dilute mineral acid after treating with an activating agent.

13. The process as claimed in claim_10,. teisinJhe_mineraLacidJs-selected-from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, nitrous acid and mixtures thereof.

14. The process as claimed in claim 1, wherein the activated catalyst carrier is dried at a temperature in the range of 100 deg C to 160 deg C, for a time period in the range of 15 to 20 hours before reacting with the trihalide catalyst.

15. The process as claimed in claim 1, wherein the reaction mixture is obtained by refluxing the activated catalyst carrier with a metal trihalide catalyst in a hydrocarbon solvent at a temperature in the range of 120 deg C to 140 deg C for a time period in the range of 10- 17 hours.

16. A process for preparation of a solid oligomerization catalyst, comprising:

treating silica with hydrogen peroxide to obtain an activated silica; refluxing the activated silica with aluminium chloride in toluene at a temperature of 120 deg C for 10 hours to obtain a reaction mixture; and

removing toluene from the reaction mixture to obtain solid oligomerization catalyst.

17. The process as claimed in claim 14, wherein the solid oligomerization catalyst is washed with toluene to remove unreacted compounds followed by drying.

18. A process for oligomerization of olefins, comprising:

mixing at least one monomer and a solid oligomerization catalyst as claimed in claim 1 to obtain a reaction mixture; and

stirring the reaction mixture for a time period in the range of 90 to 120 minutes at a temperature in the range of 70 deg C to 100 deg C to obtain an oligomeric olefinic product.

19. The process

treated with sodium hydroxide, followed by washing and distillation under, reduced pressure tp remove unreacted monomer.

20. The process as claimed in claim 16, wherein the monomer is an alpha olefin having general formula C_nH_2n; where n = 6 to 12, selected from the group consisting of 1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene and mixture thereof.

21. A process for oligomerization of olefins, comprising: mixing at least one monomer and a solid oligomerization catalyst as claimed in claim 1 to obtain a reaction mixture;

adding a hydrocarbon diluent to the reaction mixture to obtain a diluted reaction mixture, wherein the hydrocarbon diluent is selected from the group consisting of heptane, octane, decane, cyclohexane, light naphtha,heavy naphtha and mixtures thereof; and

stirring the, diluted reaction mixture for a time period in the range of 90 to 120 minutes at a temperature in the range of 70 deg C to 100 deg C to obtain an oligomeric olefinic product.

22. The process as claimed in claim 19, wherein the oligomeric olefinic product is treated with sodium hydroxide, followed by washing and distillation under reduced pressure to remove unreacted monomer.

23. The process as claimed in claim 19, wherein the monomer is an alpha olefin having general formula C_nH_2n; where n = 6 to 12, selected from the group consisting of 1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene and mixture thereof.