WO2007105875A1

WO2007105875A1 - Preparing method of light olefin trimers and production of heavy alkylates by using thereof

Info

Publication number: WO2007105875A1
Application number: PCT/KR2007/001159
Authority: WO
Inventors: Sung-Hwa Jhung; Jong-San Chang; Ji Woong Yoon; Young-Kyu Hwang; Ji-Sun Lee; Ji Hye Lee; Hee- Du Lee; Tae-Jin Kim; Seong Jun Lee; Dae Hyun Choo
Original assignee: Korea Research Institute Of Chemical Technology
Priority date: 2006-03-10
Filing date: 2007-03-09
Publication date: 2007-09-20

Abstract

The present invention relates to a preparation method of olefin oligomers, and more particularly, to a preparation method of olefin trimers with high selectivity. The oligomerization is performed with a catalyst such as a zeolite having cross linking pores; a composite acid catalyst having both Brönsted acid and Lewis acid; or a composite catalyst post-treated by calcination and/or water-washing. Furthermore, the present invention relates to a preparation method of heavy alkylates by hydrogenating olefin trimers thus formed.

Description

PREPARING METHOD OF LIGHT OLEFIN TRIMERS AND PRODUCTION OF HEAVY ALKYLATES BY USING THEREOF

[Technical Field]

The present invention relates to a preparation method of olefin trimers useful as precursors for heavy alkylates or neo acids; and heavy alkylates by the hydrogenation of the olefin trimers thus obtained. More particularly, present invention relates to a preparation method of olefin trimers, with high trimer selectivity and catalyst stability, by using zeolite catalysts containing pore structures that are crossing each other; by using composite acid catalysts that are composed of both Bronsted and Lewis acid catalysts; by using composite acid catalysts thus described, after post- treatment such as calcination or water-washing. Moreover, present invention relates to a preparation method of heavy alkylates by the hydrogenation of the olefin trimers thus obtained.

In more detail, the present invention provide an effective trimerization method with improved productivity for trimers, high trimers purity and increased catalyst life-time by using zeolites catalysts, especially composed of pore structures that are crossing each other. In addition, the present invention provides an effective trimerization method with improved productivity for trimers, high trimers purity and increased catalyst life-time by using composite acid catalysts that are composed of both Bronsted and Lewis acid catalysts; or by using the composite acid catalysts after post-treatment such as calcination at high temperature and water-washing.

[Background Art] The oligomerization of olefins has been carried out by using acid catalysts such as supported phosphoric acid, and olefin dimers have been generally obtained for a gasoline additive after hydrogenation of the dimers (USP 6689927, 6284938) . The hydrocarbons are called alkylates if the oligomers thus obtained are hydrogenated, and the alkylates have various uses depending on the number of carbons.

Alkylates have also been prepared by the alkylation of olefins with paraffins in the presence of sulfuric acid or hydrofluoric acid {Catalysis Today, 49, 193, 1999); however, the method has a severe disadvantage of environmental problem and corrosion due to the usage of the liquid acids. Heavy alkylates with Cg or more carbons are obtained, in low content of 5-10%, by the alkylation, and are used as prime solvent or diesel additive to increase the cetane-number of diesel fuel. Therefore, development of a new process to produce heavy alkylate is necessary because the productivity is limited by conventional methods .

Recently, several oligomerization methods to prepare trimers have been undertaken. Olefin trimerization has mainly been carried out by using solid acid catalysts such as a heteropoly acid (JP 2005015383), a zirconia (JP 2005015384), a molecular sieve called Al-TS-I (USP 6914165) and a sulfated titania (J. Molecular Catalysis A, 228, 333, 2005) . Ionic liquids are also used for the reaction (CNP 1379005) . A few examples have also been reported to utilize cation exchange resins for the oligomerization. It has been claimed that a cation exchange resin can be used in a dimerization (USP 2005/0119111A1) . USP 5789643 taught that oligomerization could be catalyzed by zeolites, aluminas and ion exchange resins. Tetramers or pentamers could be obtained by the oligomerization of pre-formed dimers with ion exchange resins (USP 6239321) .

Moreover, the present authors have claimed that (Kor. Patent Application 10-2006-0012317) trimers selectivity can be maintained high by using macroporous cation exchange resins in proton form and maintaining reaction conversion high. Moreover, an ion exchange resin called Amberlyst-15 was used in the oligomerization of isobutene (Catalysis Today, 100, 463, 2005) . However, the conversion was less than 40% and dimers, rather than trimers, were the main products. Additionally, a few attempts are known to use zeolite catalysts in oligomerization (Catalysis Today, 100, 463,

2005) ; however, dinners are main products over zeolites such as H-ZSM-5, Y and mordenite, and reactivity after 3-4 h was negligible due to rapid deactivation.

It has been known that the oligomerization proceeds via carbenium-ion intermediates that are formed by the addition of proton to a double bond {Ind. Eng. Chem. Res., 36, 4452, 1997). Therefore, this kind of oligomerization can be performed easily over Brδnsted acid catalysts, and several studies have been carried out over zeolites, ion exchange resins, etc. that can provide protons; however, the scope of researches was severely limited.

Especially, the contents and scope of studies for trimers, compared with the researches on dimerization, are very limited even though the uses of trimers are increasing recently.

Moreover, there is little reported result on the trimerization reaction using zeolites. Furthermore, there is no result related to the trimerization to utilize zeolites having special pore structure as catalysts or no attempt to control the ratio of Lewis acid/Bronsted acid.

Therefore, there remains a need in the art for the development of a novel process for preparing olefin trimers by using solid acid catalysts such as zeolites with special pore structure or catalysts having suitable Lewis acid/Brδnsted acid ratio or catalysts having both Brδnsted and Lewis acids after suitable post-treatment.

[Disclosure]

[Technical Problem]

The present inventors have made intensive researches to overcome the shortcomings described above, and as a result, found a novel trimerization process, in which a zeolite that has crossing pore structures is used in the reaction; or process in which a composite catalyst having both Lewis acid and Brδnsted acids is used in the reaction; or process in which a composite catalyst, after post-treatment such as calcination and water-washing, is used in the trimerization. The trimerization reactions thus performed show surprisingly increased reaction stability and trimers yield. Moreover, a heavy alkylate is obtained by the hydrogenation of trimers that are derived from the trimerization.

Accordingly, the object of this invention is to provide a process for producing olefin trimers with high trimers selectivity, high throughput and long catalyst life. Moreover, this invention is intended also to provide a method for producing a heavy alkylate by the hydrogenation of the trimers thus obtained. [Technical Solution]

The present invention is directed to a novel process for preparing olefin trimers by oligomerization of olefins, wherein zeolites having crossing pore structures; or composite catalysts having both Lewis acid and Bronsted acids; or the composite catalysts that are after-treated with a process such as calcination and water-washing are used as catalysts. The present invention is also directed to a process for preparing heavy alkylates by the hydrogenation of olefin trimers thus obtained.

More specifically, the present invention provides a novel trimerization process, with remarkably high throughput, selectivity and stability, by using a zeolite catalyst having pore composed of ten oxygens (called 10 membered ring or 10 MR) and another pore crossing the 10 MR pores or by using a zeolite catalyst having pore composed of 12 MR and another 12 MR pore crossing the 12MR.

Moreover, the present invention provides a novel trimerization process, with even higher throughput, selectivity and stability, by using a composite catalyst having both Lewis and Bronsted acids or by using the composite catalyst after post-treatment such as calcination and water-washing. For example, olefin trimerization, with even higher throughput, selectivity and stability, can be effectively carried out, for example, by zeolite containing ^Λextra-framework aluminum' obtained by dealumination of a zeolite; or by zeolite or aluminophosphate (AlPO) type catalysts further containing Lewis acid such as FeCl₃, AlCl₃, TiCl₄, etc. via ion exchange, supporting and physical mixing; or by calcination or successive water-washing the zeolites or aluminophosphate type catalysts containing Lewis acids.

Another scope of the present invention includes the production of heavy alkylates containing Cg or higher carbon by the hydrogenation of the olefin trimers selectively obtained by the invention. In the present invention, the hydrogenation is described only briefly because hydrogenation is conducted relatively easily in the presence of a precious metal or nickel as described in ^λFine chemicals through heterogeneous catalysis, Wiley-VCH, 2001, pp. 351-426' .

[Description of Drawings]

Fig. 1 represents the X-ray diffraction pattern of K-SUZ- 4, obtained in Example of Synthesis.

Fig. 2 represents the change of conversion and selectivities with reaction time in the isobutene oligomerization, obtained in Example 1.

Fig. 3 represents the change of conversion and selectivities with reaction time in the isobutene oligomerization, obtained in Example 3. Fig. 4 represents the change of conversion and selectivities with reaction time in the isobutene oligomerization, obtained in Comparative Example 1.

Fig. 5 represents the change of conversion and selectivities with reaction time in the isobutene oligomerization, obtained in Example 5.

Fig. 6 represents the change of conversion with reaction time in the isobutene oligomerization, obtained in Examples 8-10 and Comparative Example 4.

Fig. 7 represents the change of conversion with reaction time in the isobutene oligomerization, obtained in Examples 11 and Comparative Example 5.

[Best Mode]

The present invention will be described in more detail as follows:

The olefins described in this invention are any olefins composed of C₂ or higher carbon, preferentially to be C₃ or C₄ unsaturated hydrocarbons, and more preferentially to be butenes (CaH₈) and isobutene is the most suitable olefin. Olefins composed of Cg or more carbons are obtained by the oligomerization, and olefins containing C₉ or more carbons are suitable, and olefins containing Ci₂ are most suitable.

The oligomerization temperature does not have any limitation; however, the preferential temperature is from room temperature to 120 ⁰C. The reaction rate should be low when the temperature is too low, whereas, the conversion at high temperature is not high, due to the exothermal oligomerization reaction, and polymeric compounds can be obtained easily if the temperature is too high. The reaction temperature of 50-100 °C is more suitable.

The oligomerization can be performed both in batch mode and continuous mode, and the latter method is suitable for mass production of oligomers. The continuous mode is operated well by using a stirred reactor or a fixed bed reactor, and the reactants can be flown upward or downward for the case of a fixed bed reactor.

It is advisable to use a solvent to control the heat of reaction because the oligomerization is very exothermic. Moreover, a solvent is helpful to transport reactants and products easily. As a solvent, hydrocarbons such as C₂-Ci₀ paraffins can be used. More preferably, isobutane, n-butane, pentanes, hexanes, heptanes, octanes, nonanes or decanes can be used. Cyclohexane can also be utilized as a solvent. The reactant/solvent ratio can be any value between 1/100 and 100/1 (wt/wt) , and it is preferable to maintain the ratio between 1/10 and 10/1 because of the operation convenience and high productivity. Inert gases such as nitrogen, argon, carbon dioxide and helium can be used as a diluent instead of an organic solvent. It is good to flow the reactant and the inert gas upward when diluent is used in a fixed bed reactor. Any zeolite that has crossing pore structures can be applied for the oligomerization, and zeolites having 10 MR or 12 MR are preferred. The pore that crossing the 10 MR can be 8 MR and/or 6 MR. SUZ-4 (USP 5118483; J. Kor. Chem. Soc, 48, 623, 2004; J. Phys . Chem. B, 103, 197, 1999; J. Phys . Chem. B, 105, 7730, 2001) or ferrierite (FER, J. Phys. Chem. B, 105, 7730, 2001) is preferable as a zeolite having crossing pore structure, and they have 10 MR that is crossed with 8 MR. Zeolite iso-structural to FER such as FU-9 (EP B-55529, 1985), ISI-6 (USP 4578259), NU-23 (EP A-103981), Sr-D (J. Chem. Soc, 2296-2305, 1964), ZSM-35 (USP 4016245) and monoclinic FER (Am. Mineral. , 70, 619, 1985) can also be applied.

As an example of zeolites that has pore composed of 12 MR, zeolite which has extra-pore (composed of 12 MR and/or 10~6 MR) crossing the 12 MR is suitable. Among the zeolites with 12 MR and crossing 12-6 MR, zeolite beta (BEA, having 12 MR and crossing 12 MR, Zeolites, 8, 446, 1988) is suitable because of high activity and catalyst stability. Zeolite iso-structural to BEA such as Al-rich beta (Microporous Materials, 5, 289-297, 1996), B-containing beta (Proc. 9th Int. Zeolite Conf. , pp. 425-432, 1993; J. Incl. Phenom. MoI. Recogn. Chem., 20, 197- 210, 1994), Ga-containing beta (J^". Incl. Phenom. MoI. Recogn. Chem., 20, 197-210, 1994), Ga-containing beta (Chem. Commun. , 2367-2368, 1996), CIT-6 (Topics in Catalysis, 9, 35-42, 1999) , pure-silica beta {Chem. Commun. , 2365-2366, 1996) and Tschernichite (Am. Mineral., 78, 822-826, 1993) can also be applied.

Any zeolite can be used as a trimerization catalyst as long as it has at least small amount of acid sites. Zeolite in any form can be used because zeolite has intrinsic acidity. Zeolite in proton- form is more suitable because of high acidity and high catalytic activity, and proton-exchanged zeolite with the degree of ion exchange higher than 50% is even more suitable.

On the other hand, the composite acid catalyst of the present invention means any acid catalyst composed of both Lewis acid and Brδnsted acid or any composite acid catalyst that is further treated with calcination, water-washing, etc. As a Brόnsted acid, any one selected from proton- or ammonium- zeolites; aluminophosphate-type molecular sieves; cation exchange resins containing functional group of sulfonic acid, carboxylic acid or phosphoric acid; and phosphoric acid supported on a support can be applicable. For the case of AlPO-type molecular sieves, metal-incorporated AlPO molecular sieves are suitable because the AlPO-type molecular sieves have acidity when suitable metals (to have oxidation state of 2 or 4 , for example, Si, Mg, Ti, V, Cr, Mn, Fe, Co, Ni, etc.) are incorporated in the framework. Any material can be a Lewis acid if it can receive an electron, and typical element for Lewis acid can be Al, Fe, B or Ga. Materials that are described as MX_n are well known Lewis acids. M means metallic elements selected from III, IVa, IVb, V and Vl-family of the periodic table. X means halogen element such as F, Cl, Br and I, and n represents the valance of M. For example, BF₃, BCl₃, BBr₃, BI₃, SbF₅, SbCl₅, AlCl₃, AlBr₃, TiCl₄, TiBr₄, ZrCl₄, PF₅, FeCl₃, FeBr₃, GaCl₃, SnBr₄, SnCl₄ are typical Lewis acids. Extraframework aluminum species in a zeolite belong to the Lewis acid of the present invention because it is known that the extraframework aluminum species, obtained by dealumination of zeolites or related materials, have the characteristics of a Lewis acid (J^". Catalysis, 9, 225, 1967) . Any Lewis acid that is generally regarded as a Lewis acid is not restricted in the present invention.

The composite acid catalyst, containing both Lewis and Brόnsted acids, used in the present invention is applied in the acid catalytic reaction, trimerization, after preparation by loading Lewis acid on a solid such as zeolites, aluminophosphate-type molecular sieves or cation exchange resins via physical mixing, ion exchange or supporting, etc. Ion exchange can be carried out by both solid state reaction and liquid phase reaction; however, solid phase reaction is more suitable because metal ions with high oxidation states are used. Solid state ion exchange can generally be carried out by calcination at high temperature after physical mixing. Organic solvents are preferable in liquid phase ion exchange or supporting using a solvent in order to prevent a hydrolysis of Lewis acids. As an organic solvent, benzene, carbon tetrachloride, toluene, cyclohexane, etc. can be used, and solvent with low polarity is more preferable. The supporting process is well-explained in an open literature (Chem. Rev., 103, 4307, 2003) and HCl can be removed during supporting.

Lewis acid can be used for the present invention without any treatment after loading on a solid support. Moreover, the loaded Lewis acid can be used as an acid catalyst after treatment such as heating and water-washing. The Lewis acid can be bonded to a Brόnsted acid, or can be well dispersed or can be ion-exchanged. Lewis acid, partly blocking the pore structure of a catalyst, can be removed by water-washing. There is no limitation for the Brδnsted acid/Lewis acid ratios; however, the Brόnsted acid/Lewis acid ratio can preferentially be between 99:1 and 1:99 because the effect of Lewis acid does not occur if the content of Lewis acid is too low and the initiation of the reaction is difficult if the content of Brόnsted acid is too low.

The Lewis acid in the present invention can be the inorganic Lewis acid mentioned above and extra-framework aluminum species, obtained from dealumination, for the case of zeolites. The acid catalysts containing both Lewis and Brόnsted acids are physical mixtures of Lewis and Brόnsted acids or the post-treated Lewis and Brδnsted acids by a suitable process. The post-treated catalysts are effective because the Brόnsted acid and Lewis acid are near each other, and can be obtained by calcination or water-washing the Lewis acids such as FeCl₃ and AlCl₃ that are loaded on proton-type zeolites or aluminophosphate-type molecular sieves or proton- type zeolites after dealumination.

Concrete examples for the composite acid catalysts are the aforementioned MX_n which are loaded, by physical mixing, ion-exchange and impregnation, on zeolites or AlPO-type molecular sieves of proton- or ammonium- form, or on cation- exchange resins which have at least one form selected from sulphonic acid, carboxylic acid and phosphoric acid. As the MX_n, any one or more than one of the material selected from the materials such as BF₃, BCl₃, BBr₃, BI₃, SbF₅, SbCl₅, AlCl₃, AlBr₃, TiCl₄, TiBr₄, ZrCl₄, PF₅, FeCl₃, FeBr₃, SnBr₄, SnCl₄ can be used. The above mentioned molecular sieves can be anyone selected from zeolites or AlPO molecular sieves. Zeolites or AlPO molecular sieves having crossing channels are especially suitable, and for example, zeolites beta, ferrierite, SUZ-4 and Y are more suitable.

The zeolites having crossing pore, composite acid catalysts having both Lewis and Brδnsted acids, or the composite catalysts post-treated by calcination or water- washing can be used as the state of powder or granule by shaping. The catalysts can be used as a shaped form such as pellet, sphere and extrudate. Shaped catalysts such as granule and pellet are more suitable in order to reduce the pressure drop. Catalyst with size greater than 0.1 mm is more suitable, and the size of 0.2-1.0 mm is most suitable for the operation ability and low pressure drop.

Olefin conversion does not have any limitation as long as the conversion is higher than 50% because the selectivity of olefin trimers increases with increasing olefin conversion. More preferably, the conversion should be higher than 90% for practical application. If the conversion is too low the formation of impurities such as olefin dimers is high, whereas olefin tetramers or oligomers with high molecular weight can be increased slightly when the olefin conversion is too high, requiring the increase of concentration of diluent or solvent.

The productivity is low and the concentration of high molecular weight impurity is high when the flow rate or space velocity of reactant is too low. On the other hand, the olefin conversion and trimers selectivity are low if the space velocity is too high. The suitable space velocity, based on the olefin WHSV (weight hourly space velocity) , is 0.5-100 h^"1, and more preferably the velocity is 1-50 h^"1. The trimers that obtained from the olefin oligomerization can be utilized directly for the production of Chemicals such as neo-acid or can be converted to heavy alkylate by hydrogenation. Heavy alkylates containing Cg or higher carbons are obtained by hydrogenation of the olefin trimers that are prepared by this invention. The hydrogenation for heavy alkylate can be performed with any conventional reactors such as a fixed bed reactor and a continuous stirred reactor. Hydrogenation catalyst can be selected from any supported catalysts such as Pd/C, Pd/alumina, Pd/silica, Pd/silica-alumina, Pt/C, Pt/alumina, Pt/silica, Pt/silica-alumina, Ru/C, Ru/alumina, Ru/silica, Ru/silica-alumina, Ni/C, Ni/alumina, Ni/silica and Ni/silica- alumina. Or, the mixed catalysts containing two or more of the above mentioned catalysts can be applicable. Furthermore, supported mixed catalyst that containing two or more metals from Pd, Pt, Ru, Ni can be used for the hydrogenation. The hydrogenation can be carried out in any phase such as liquid- or gas-phase and any concentration of hydrogen is affordable as long as the total amount of hydrogen is higher than the stoichiometric amount that is needed for the hydrogenation.

The following specific examples are intended to be illustrative of the invention and should not be construed as limiting the scope of the invention as defined by appended claims . EXAMPLE OF SYNTHESIS: synthesis of K-SUZ-4 and H-SUZ-4

Reaction mixtures containing water (50 mL) , KOH (3.29 g) and aluminum foil (0.4g) were mixed at 60 ⁰C for 12 h until it become clear solution. TEAOH (tetra ethylammonium hydroxide, 7.93g) was added to the above clear solution, and mixed further for 1 h. Finally, silica sol (Aldrich, Ludox-HS-40, 40 wt% Siθ2, 18.2 g) was added further and stirred for another 1 h. Above solution was heated at 165 °C for 48 h under autogenous pressure. During the heating for synthesis, the reactant mixture was stirred at the speed of 250 rpm. The solid product was filtered, washed with distilled water until neutral pH and dried at 120 ⁰C for 12 h. Highly crystalline SUZ-4 (KsAl₅Si₃iθ7₂) was obtained by the calcination of the dried product at 550 ⁰C, and the product was named as K-SUZ-4. The XRD pattern (Fig. 1) of the zeolite K-SUZ-4 agree well with the patterns reported in the literatures (J. Kor. Chem. Soc, 48, 623, 2004; J. Phys . Chem. B₁ 103, 197, 1999) and the surface area of K-SUZ-4 was 380 m²/g. Calcined K-SUZ-4 zeolite (1.5 g) was added to an aqueous solution of ammonium nitrate (IN, 20 mL) and stirred for 6 h at 80 ⁰C in order to prepare an ion-exchanged zeolite. The obtained product was filtered, washed three times with distilled water, dried at 120 ⁰C and calcined at 600 °C . The H-SUZ-4 (H_3-8Ki_-2Al₅Si_3IO₇₂) was obtained by the above mentioned ion-exchange procedure, including ion-exchange, filter, washing, drying and calcination, in four times.

EXAMPLE 1

The oligomerization of isobutene was carried out at 70 ⁰C by using a fixed bed reactor containing 2 g of the H-SUZ-4

(diameter: 0.2 - 1.0mm) that was obtained in the Example of

Synthesis and by flowing n-butane and isobutene (1:1 wt ratio) upward. The catalyst was pre-treated at 300 ⁰C for 10 h by flowing nitrogen. The flow rates of hydrocarbons were controlled by mass flow controllers and the isobutene flow rate was adjusted for the isobutene WHSV (weight hourly space velocity) to be 10 h^"1. The reaction temperature was maintained constant by using a liquid circulator. Circulated water at fixed temperature absorbs extra heat generated from the oligomerization. The isobutene conversion was calculated by measuring the total flow rates of n-butane and isobutene with mass flow meters. The isobutene conversion was re- checked by the analysis of gas-phase effluent by using a gas chromatography (GC) . The liquid product, after using a cold trap, was analyzed by a GC for the composition of dimers, trimers and tetramers. As shown in Table 1, the isobutene conversion, trimers selectivity and dimers selectivity were 99.9%, 68.8 wt% and 11.2 wt%, respectively, after the reaction time of 20 h. As shown in Fig. 2, the conversion and trimers selectivity were very high under the reaction condition. Detailed reaction conditions and reaction results are summarized in Table 1.

EXAMPLE 2 The oligomerization was carried out as Example 1, except that the K-SUZ-4 catalyst that was obtained in the Example of Synthesis was used instead of H-SUZ-4 catalyst. The isobutene conversion, trimers selectivity and dimers selectivity were 99.5%, 51.9 wt% and 28.4 wt%, respectively, after 20 h of reaction. Detailed reaction conditions and reaction results are summarized in Table 1.

EXAMPLE 3

The oligomerization was carried out as Example 1, except that a commercial ferrierite (Zeolyst, CP914C, SiO₂/Al₂O₃=20) catalyst, after calcination at 500 °C, was used instead of H-

SUZ-4 catalyst. The calcination was carried out using a furnace oven to remove ammonia and convert into proton form of ferrierite (H-FER) . The calcined catalyst was granulated by pressing using a press. The isobutene conversion and trimers selectivity were 94.7% and 56.5 wt%, respectively, after 15 h of reaction. Detailed reaction conditions and reaction results are summarized in Table 1 and Fig. 3.

EXAMPLE 4: Hydrogenation Ten (10) grams of isobutene trimers, obtained in Example 1 and purified with distillation, were loaded in a continuous stirred reactor. Cyclohexane (90 g) was added as a solvent. Catalyst basket containing 0.5 g of Pd (5%) /C was mounted on the stirring shaft. The reactor temperature was maintained at 100 ⁰C and the reactor pressure was raised to 10 atm by using hydrogen. The hydrogenation was started by the onset of agitation, and the reactor pressure was maintained constant (10 atm) by using a back pressure regulator. After reaction for 1 h, the product was separated from cyclohexane by distillation. By the analysis using GC/mass spectrometry, it was confirmed that the conversion of olefins to paraffins was 99.5%, and a heavy alkylate was successfully obtained.

COMPARATIVE EXAMPLE 1

The oligomerization was carried out as Example 1, except that H-mordenite catalyst was used instead of H-SUZ-4 catalyst. The H-mordenite was obtained by calcination of mordenite in ammonium form (Zeocat, SiO₂/Al₂O₃=25) at 550 ⁰C using a furnace oven. Mordenite has one-dimensional channel of 12 MR without crossing pores. Even though, the initial activity was high, the isobutene conversion and trimers selectivity were 20.0% and 8.7 wt%, respectively, after 12h of reaction. Detailed reaction conditions and reaction results are summarized in Table 1 and Fig. 4. It was confirmed that the conversion was low and the trimers selectivity was very low even though the reaction time was very short .

COMPARATIVE EXAMPLE 2

The oligomerization was carried out as Example 1, except that H-SAPO-Il catalyst was used instead of H-SUZ-4 catalyst. The H-SAPO-Il catalyst, having 1-dimensional pore of 10 MR rather than crossing pore system, was obtained by the method of USP 6303534. The as-synthesized SAPO-Il was calcined at 550 ⁰C for 10 h, ion-exchanged with ammonium chloride and calcined for 10 h at 500 ⁰C using an electric oven. The initial activity was not high, and the isobutene conversion and trimers selectivity were 12.0% and 15.2 wt%, respectively, after short reaction time of 3h. Detailed reaction conditions and reaction results are summarized in Table 1. It was confirmed that the conversion was low and the trimers selectivity was very low even though the reaction time was very short.

[Table 1] Reaction conditions for oligomerization and reaction results.

EXAMPLE 5

The catalyst H-beta was used as a catalyst. The H-beta catalyst was obtained by the calcination of beta zeolite (NH₄- form, Zeolyst, CP814E, SiO₂/Al₂O₃=25) at 550 ⁰C for 8 h to convert it into beta zeolite in proton-form. The oligomerization of isobutene was carried out at 70 ⁰C by using a fixed bed reactor containing 2 g of above H-beta (diameter: 0.2 - 1.0mm, pellet-type) and by flowing n-butane and isobutene (1:1 wt ratio) upward. The flow rates of hydrocarbons were controlled by mass flow controllers and the isobutene flow rate was adjusted for the isobutene WHSV (weight hourly space velocity) to be 10 h^"1. The reaction temperature was maintained constant by using a liquid circulator. Circulated water at fixed temperature absorbs extra heat generated from the oligomerization . The isobutene conversion was calculated by measuring the total flow rates of n-butane and isobutene with mass flow meters. The isobutene conversion was re-checked by the analysis of gas- phase effluent by using a GC. The liquid product, after trapping using a cold trap, was analyzed by a GC for the composition of dimers, trimers and tetramers. As shown in Fig. 5, after the reaction time of 60 h, the reaction was very stable, and the isobutene conversion and trimers selectivity were 99.9% and 57.9 wt%, respectively. The dimers selectivity was low of 12.9 wt . % . Detailed reaction conditions and reaction results are summarized in Table 2.

EXAMPLE 6 The oligomerization was carried out as Example 5, except that the isobutene WHSV was increased to 50 h^"1 instead of the isobutene WHSV of 10 h^"1. The isobutene conversion, trimers selectivity and dimers selectivity were 94.7%, 57.6 wt% and 30.7wt%, respectively, after 12 h of reaction even under high space velocity. Detailed reaction conditions and reaction results are summarized in Table 2.

EXAMPLE 7 : Hydrogenation

Ten (10) grams of trimers, obtained in Example 5 and purified with distillation, were loaded in a continuous stirred reactor. Cyclohexane (90 g) was added as a solvent.

Catalyst basket containing 0.5 g of Pd (5%) /C was mounted on the stirring shaft. The reactor temperature was maintained at

100 ⁰C and the reactor pressure was raised to 10 atm by using hydrogen. The hydrogenation was started by the onset of agitation, and the reactor pressure was maintained constant

(10 atm) by using a back pressure regulator. After reaction for 1 h, the product was separated from cyclohexane by distillation. By the analysis using GC/mass spectrometry, it was confirmed that the conversion of olefins to paraffins was 99.5%, and a heavy alkylate was successfully obtained.

COMPARATIVE EXAMPLE 3

The oligomerization was carried out as Example 5, except that H-mordenite catalyst was used instead of H-beta catalyst. The H-mordenite was obtained by calcination of mordenite zeolite in ammonium form (Zeocat, SiO₂/Al₂O₃=25) at 550 ⁰C using an electric oven. Mordenite has one-dimensional channel of 12 MR without crossing pores. Even though, the initial activity was high, the isobutene conversion and trimers selectivity were 20.0% and 8.7 wt%, respectively, after 12h of reaction. Detailed reaction conditions and reaction results are summarized in Table 2. It was confirmed that the conversion was low and the trimers selectivity was very low even though the reaction time was very short.

[Table 2] Reaction conditions for oligomerization and reaction results.

EXAMPLE 8

Y-type zeolite (NH₄-form, Strem chemicals, SiO₂/Al₂θ₃=3.25) was converted into proton form (HY) by calcination for 8 h at 550 ⁰C. After that, the zeolite was dealuminated at 600 ⁰C in order for a Lewis acid to be formed. The zeolite was dried at 600 ⁰C for 3 h, and further treated at 600 ⁰C for 12 h under the flow of water-saturated helium (zeolite 5g, He 50 cc/min) , and finally cooled for 1 h under the flow of helium without water. The catalyst thus obtained is designated as HY(600).

The oligomerization of isobutene was carried out at 70 ⁰C by using a fixed bed reactor containing 2 g of above HY (600) (diameter: 0.2 - 1.0mm, pellet-type), after pressing, and by flowing n-butane and isobutene (1:1 wt ratio) upward. Before the reaction, the HY (600) was treated with nitrogen at 300 ⁰C for 1Oh to remove moisture. The flow rates of hydrocarbons were controlled by mass flow controllers and the isobutene flow rate was adjusted for the isobutene WHSV (weight hourly space velocity) to be 10 hf¹. The reaction pressure was controlled to be 15 bar by using a back pressure regulator. The reaction temperature was maintained constant by using a liquid circulator. Circulated water at fixed temperature absorbs extra heat generated from the oligomerization . The isobutene conversion was calculated by measuring the total flow rates of n-butane and isobutene with mass flow meters. The isobutene conversion was re-checked by the analysis of gas-phase effluent by using a GC. The liquid product, after trapping using a cold trap, was analyzed by a GC for the composition of dimers, trimers and tetramers. As shown in Fig. 6, through the reaction of 6 h, the reaction was very stable over the catalyst dealuminated under the flow of steam, compared with the HY zeolite without dealumination (C. Ex. 4). Detailed reaction conditions and reaction results are summarized in Fig. 6.

EXAMPLE 9

The HY (calcined NH₄-Y) of Ex. 8 was dried at 400 ⁰C for

4 h and cooled in a glove box. The FeCl₃ (0.3 g) was added to the HY (9.7 g) , and the mixture was ground well for 10 min in the glove box using a mortar. The prepared catalyst was stored after sealing and named as FeCl₃+HY. A fixed amount of the catalyst, after pressing, was used in the oligomerization. The oligomerization was carried out as Example 8, except that FeCl₃+HY catalyst was used instead of HY(600) catalyst. As shown in Fig. 6, the reaction stability was good, compared with the stability over HY (C. Ex. 4) through reaction for 6 h. Detailed reaction conditions and reaction results are summarized in Table 3, and the isobutene conversion is shown in Fig. 6.

EXAMPLE 10

The FeCl₃+HY catalyst of Ex. 9 was heated to 550 ⁰C with the heating rate of 1 ⁰C /min and maintained for 6 h at 550 ⁰C using a furnace. The prepared catalyst was stored after sealing and named as FeCl₃ZHY. A fixed amount of the catalyst, after pressing, was used in the oligomerization. The oligomerization was carried out as Example 8, except that FeCl₃/HY catalyst was used instead of HY (600) catalyst.

As shown in Fig. 6, the reaction stability was good, compared with the stability over HY (C. Ex. 4) through reaction for 6 h. Detailed reaction conditions and reaction results are summarized in Table 3, and the isobutene conversion is shown in Fig. 6.

EXAMPLE 11 The USY zeolite (H-form, Zeolyst, SiO₂/Al₂O₃=60) was dried at 400 ⁰C for 4 h and cooled in a glove box. The FeCl₃

(0.3 g) was added to the dried USY (9.7 g) , and the mixture was ground well for 10 min in the glove box using a mortar. The mixed catalyst was heated to 550 ⁰C with the heating rate of 1 °C /min and maintained for 6 h at 550 °C using a furnace.

The calcined catalyst was cooled, washed for 10 times with

200 mL of de-ionized water, heated to 100 ⁰C (heating rate: 1

°C /min), and dried for 4 h at 100 ⁰C. The prepared catalyst was stored after sealing and named as Fe/USY. A fixed amount of the catalyst, after pressing, was used in the oligomerization . The oligomerization was carried out as Example 8, except that Fe/USY catalyst was used instead of HY(βOO) catalyst. As shown in Fig. 7, the reaction stability was highly improved, compared with the stability over USY (C. Ex. 5, without the loading of FeCl₃ and treatment) through reaction for 20 h. Detailed reaction conditions and reaction results are summarized in Table 3, and the isobutene conversion with reaction time is shown in Fig. 7.

EXAMPLE 12

The catalyst was synthesized as Example 10, except that

AlCl₃ and USY support were used instead of FeCl₃ and HY support, respectively. Oligomerization was carried out as Example 10, except that the A1C1₃/USY was used instead of the FeCl₃/HY. As shown in Table 3, the reaction stability, compared with the result of C. Ex. 5, was good after the reaction time of 20 h.

EXAMPLE 13

Oligomerization was carried out as Example 8, except that a dealuminated beta catalyst was used instead of the dealuminated HY zeolite. The dealuminated beta catalyst used in this example was prepared from a beta zeolite (NH,j-form, Zeolyst, CP814E, SiO₂/Al₂O₃=25, surface area=680 m²/g) via calcination (550 ⁰C, 8 h) to transform into H-beta and subsequent dealumination (500 ⁰C, 12 h) under the flow of water-saturated helium. The obtained catalyst was named as beta (500) . The isobutene conversion and trimers yield were 99.9% and 57.9%, respectively, after 70 h of reaction time. Detailed reaction conditions and reaction results are summarized in Table 3.

EXAMPLE 14

Oligomerization was carried out as Example 8, except that a dealuminated ferrierite catalyst was used instead of the HY zeolite. The dealuminated ferrierite catalyst used in this example was prepared from a ferrierite zeolite (Zeolyst, CP914C, SiO₂/Al₂O₃=20, surface area=400 m²/g) via calcination (550 ⁰C, 8 h) to transform into H-ferrierite and subsequent dealumination (500 °C, 12 h) under the flow of water-saturated helium. The obtained catalyst was named as ferrierite (500) . The isobutene conversion and trimers yield were 99.1% and 60.9%, respectively, after 70 h of reaction time. Detailed reaction conditions and reaction results are summarized in Table 3.

EXAMPLE 15 : Hydrogenation Ten (10) grams of trimers, obtained in Example 13 and purified with distillation, were loaded in a continuous stirred reactor. Cyclohexane (90 g) was added as a solvent. Catalyst basket containing 0.5 g of Pd (5%) /C was mounted on the stirring shaft. The reactor temperature was maintained at 100 ⁰C and the reactor pressure was raised to 10 atm by using hydrogen. The hydrogenation was started by the onset of agitation, and the reactor pressure was maintained constant (10 atm) by using a back pressure regulator. After reaction for 1 h, the product was separated from cyclohexane by distillation. By the analysis using GC/mass spectrometry, it was confirmed that the conversion of olefins to paraffins was 99.5%, and a heavy alkylate was successfully obtained.

COMPARATIVE EXAMPLE 4 The oligomerization was carried out as Example 8, except that HY catalyst was used without dealumination. As shown in Fig. 6, the catalyst stability was low and the isobutene conversion after 6 h of reaction was very low. Detailed reaction conditions and reaction results are summarized in Table 3. The isobutene conversion with reaction time is shown in Fig. 6.

COMPARATIVE EXAMPLE 5

The oligomerization was carried out as Example 11, except that USY catalyst was used without loading of FeCl₃, heat treatment and water-washing. As shown in Fig. 7, the catalyst activity was decreased quite rapidly. Detailed reaction conditions and reaction results are summarized in Table 3. The isobutene conversion with reaction time is shown in Fig. 7.

[Table 3] Reaction conditions for oligomerization and reaction results.

[industrial Applicability]

As described above, the present process for preparing olefin trimers is performed by use of zeolites having cross linking pores. Moreover, olefin trimerization reaction, with higher conversion, especially high stability and high yield, can be carried out by composite acid catalysts having both Bronsted acid and Lewis acids; or by composite acid catalysts that are post-treated by calcination, water-washing, etc. The olefin trimers thus obtained can be used for preparing neo- acid or can be hydrogenated to heavy alkylate that is used for a prime solvent or diesel additive.

Claims

[CLAIMS]

[Claim l]

A preparation method of olefin trimers, wherein acid catalysts selected from a) Zeolites having cross linking pores structure; or b) Composite acid catalysts having both Brόnsted acid and Lewis acid; or c) The composite acid catalysts described in b) that is further treated by calcination and/or water-washing, is used as a catalyst.

[Claim 2]

The preparation method of olefin trimers according to claim 1, wherein the ^λzeolites having cross linking pores' are zeolites having pores composed of 10-membered rings and another pores composed of 8- or 6-membered rings that are crossing with the pores composed of 10-membered rings. [Claim 3]

The preparation method of olefin trimers according to claim 1, wherein the ^Λzeolites having cross linking pores' are zeolites having pores composed of 12-membered rings and another pores composed of 12- or between 10- and 6-membered rings that are cross linking pores composed of 12-membered rings .

[Claim 4] The preparation method of olefin trimers according to claim

\ 2, wherein the ^λzeolites having cross linking pores' are zeolite having the structure of SUZ-4, ferrierite, FU-9, ISI- 6, NU-23, Sr-D, ZSM-35 or monoclinic ferrierite.

[Claim 5] The preparation method of olefin trimers according to claim 4, wherein the ^Λzeolites having cross linking pores' are zeolite having the structure of SUZ-4.

[Claim β)

The preparation method of olefin trimers according to claim 3, wherein the ^zeolites having cross linking pores' are zeolite having the structure of beta, aluminum-rich beta, boron-containing beta, gallium-containing beta, titanium- containing beta, CIT-β, silica-beta, or tschernichite .

[Claim 7] The preparation method of olefin trimers according to claim 6, wherein the ^zeolites having cross linking pores' are zeolite having the structure of beta.

[Claim 8]

The preparation method of olefin trimers according to claim 1, wherein the ^Λzeolites having cross linking pores' are zeolites of proton form.

[Claim 9]

The preparation method of olefin trimers according to claim 1, wherein the reaction temperature and space velocity are 50-100 ⁰C and 0.5-100 h^"1, respectively. [Claim l θ ]

The preparation method of olefin trimers according to claim 1, wherein olefin conversion is higher than 50%.

[Claim 11] The preparation method of olefin trimers according to claim 1, wherein said olefin is isobutene.

[Claim 12]

A preparation method of heavy alkylates by hydrogenation of olefin trimers that are obtained according to any one of claims 1 to 11.

[Claim 13]

The preparation method of heavy alkylates according to claim 12, wherein hydrogenation catalyst is composed of one or more catalysts selected from supported Pd, Pt, Ru and Ni catalysts and hydrogenation agent is hydrogen.

[Claim 14]

The preparation method of olefin trimers according to claim 1, wherein the Brδnsted acid/Lewis acid ratio of the composite acid catalyst is between 99/1 and 1/99.

[Claim 15]

The preparation method of olefin trimers according to claim 14, wherein the composite acid catalyst is prepared by loading one or more of the materials selected from BF₃, BCl₃, BBr₃, BI₃, SbF₅, SbCl₅, AlCl₃, AlBr₃, TiCl₄, TiBr₄, ZrCl₄, PF₅, FeCl₃, FeBr₃, SnBr₄, and SnCl₄ on zeolites of hydrogen-form, molecular sieves such as aluminophosphates and metal aluminophosphates or cation-exchange resins containing one or more of acid groups selected from sulfonic, carboxylic and phosphoric acid groups. [Claim 16] The preparation method of olefin trimers according to claim 1, wherein the said acid catalyst is prepared by dealumination of zeolites in proton or ammonium-form.

[Claim 17]

The preparation method of olefin trimers according to claim 16, wherein said zeolites have crossing pores.

[Claim 18]

The preparation method of olefin trimers according to claim 1, wherein the reaction temperature and space velocity are 50-200 ⁰C and 0.5-100 h^"1, respectively.

[Claim 19]

The preparation method of olefin trimers according to claim 16 or 17, wherein the zeolite is selected from beta, ferrierite, SUZ-4 or Y.

[Claim 20] A preparation method of heavy alkylates by hydrogenation of olefin trimers that are obtained according to any one of claims 14 to 18 . [Claim 21]

The preparation method of olefin trimers according to claim 20, wherein hydrogenation catalyst is composed of one or more catalysts selected from supported Pd, Pt, Ru and Ni catalysts and hydrogenation agent is hydrogen.