METHOD FOR MANUFACTURING OF MULTI-LEVEL PORE ZEOLITE AND UTILIZATION AS CATALYST FOR HYDROISOMERIZATION OF NORMAL PARAFFINS OF MULTI-LEVEL PORE ZEOLITE PREPARED THEREBY

Abstract

The present disclosure relates to a method for preparing a multi-level pore zeolite, including: (A) a step of mixing a silicon precursor, an aluminum precursor, a phosphorus precursor, a structure directing agent and water; a step of (B) adding phenylphosphonic acid, carbon black or a mixture thereof to the mixture prepared in the step (A) and mixing the same; a step of (C) crystallizing the mixture prepared in the step (B) by heat-treating the same; and a step of (D) calcining the crystallization product, and utilization of the prepared multi-level pore zeolite as a catalyst for hydroisomerization of normal paraffins. The catalyst exhibits improved isoparaffin yield when it is used as a catalyst for hydroisomerization of normal paraffins such as diesel or lube base oil by supporting an active metal component because residence time of reactants and products in the zeolite crystals are decreased due to mesopores and the proportion of external acid sites to total acid sites is low. Also, cloud point and pour point are effectively improved and high hydroisomerization reactivity is achieved without product loss.

Claims

1. A method for preparing a multi-level pore zeolite, comprising: (A) mixing a silicon precursor, an aluminum precursor, a phosphorus precursor, a structure directing agent and water; (B) adding phenylphosphonic acid, carbon black or a mixture thereof to the mixture prepared in (A) and mixing the same; (C) crystallizing the mixture prepared in (B) by heat-treating the same; and (D) calcining the crystallization product, wherein the multi-level pore zeolite has 10-30 vol % of micropores having a diameter of 0.1-1.9 nm based on the volume of total pores, 50-70 vol % of mesopores having a diameter of 2.0-50.0 nm based on the volume of total pores and 5-20 vol % of macropores having a diameter of 50.1-60.0 nm based on the volume of total pores.

2. The method for preparing a multi-level pore zeolite according to claim 1, wherein, in (A), the silicon precursor is one or more selected from a group consisting of silica sol, fumed silica, tetraethyl orthosilicate and tetrapropyl orthosilicate; the aluminum precursor is aluminum isopropoxide, pseudoboehmite or a mixture thereof; the phosphorus precursor is phosphoric acid, phosphorous acid or a mixture thereof; and the structure directing agent is one or more selected from a group consisting of dipropylamine, triethylamine, tripropylamine, dibutylamine and heptylamine.

3. The method for preparing a multi-level pore zeolite according to claim 1, wherein, in (B), when the phenylphosphonic acid is added alone, a molar ratio of the water/phenylphosphonic acid is 45.5-1,000.

4. The method for preparing a multi-level pore zeolite according to claim 1, wherein, in (B), when the phenylphosphonic acid is added alone, a molar ratio of the structure directing agent/phenylphosphonic acid is 0.9-38.0.

5. The method for preparing a multi-level pore zeolite according to claim 1, wherein, in (B), when the phenylphosphonic acid is added alone, a molar ratio of the phosphorus precursor/phenylphosphonic acid is 1.8-40.0.

6. The method for preparing a multi-level pore zeolite according to claim 1, wherein, in (B), when the phenylphosphonic acid is added alone, a molar ratio of total phosphorus (P.sub.2O.sub.5) contained in the phosphorus precursor and phenylphosphonic acid/aluminum (Al.sub.2O.sub.3) is 1.0-1.6.

7. The method for preparing a multi-level pore zeolite according to claim 1, wherein, in (B), when the carbon black is added alone, it is added in an amount of 1-250 parts by weight based on 100 parts by weight of the multi-level pore zeolite and a weight ratio of the structure directing agent/carbon black is 0.5-50.

8. The method for preparing a multi-level pore zeolite according to claim 1, wherein, in (B), when a mixture of the phenylphosphonic acid and the carbon black is added, a molar ratio of the water/phenylphosphonic acid is 45.5-1,000.

9. The method for preparing a multi-level pore zeolite according to claim 1, wherein in (B), when a mixture of the phenylphosphonic acid and the carbon black is added, a molar ratio of the structure directing agent/phenylphosphonic acid is 0.9-46.0.

10. The method for preparing a multi-level pore zeolite according to claim 1, wherein in (B), when a mixture of the phenylphosphonic acid and the carbon black is added, a molar ratio of the phosphorus precursor/phenylphosphonic acid is 1.8-40.0.

11. The method for preparing a multi-level pore zeolite according to claim 1, wherein in (B), when a mixture of the phenylphosphonic acid and the carbon black is added, a molar ratio of total phosphorus (P.sub.2O.sub.5) contained in the phosphorus precursor and phenylphosphonic acid/aluminum (Al.sub.2O.sub.3) is 1.0-1.6.

12. The method for preparing a multi-level pore zeolite according to claim 1, wherein, in (B), when a mixture of the phenylphosphonic acid and the carbon black is added, the carbon black is added in an amount of 1-250 parts by weight based on 100 parts by weight of the multi-level pore zeolite.

13. The method for preparing a multi-level pore zeolite according to claim 1, wherein, in (A), a molar ratio of aluminum (Al.sub.2O.sub.3)/silicon (SiO.sub.2) is 2-20.

14. The method for preparing a multi-level pore zeolite according to claim 1, wherein, after the addition of the phenylphosphonic acid, the carbon black or a mixture of the carbon black and the phenylphosphonic acid, a value of (the amount of external Brnsted acid sites/the amount of total Brnsted acid sites100)/outer surface area is 0.4 or smaller.

15. The method for preparing a multi-level pore zeolite according to claim 1, wherein isoparaffins are prepared from hydrocarbon materials such as diesel or lube base oil through hydroisomerization by adding the phenylphosphonic acid, the carbon black or a mixture of the carbon black and the phenylphosphonic acid.

16. A multi-level pore zeolite prepared by the method according to claim 1, which as an average diameter of 1-50 nm.

17. (canceled)

18. A catalyst for hydroisomerization of normal paraffins, which is prepared by supporting an active metal component on the multi-level pore zeolite according to claim 16.

19. The catalyst for hydroisomerization of normal paraffins according to claim 18, wherein the active metal component is one or more selected from a group consisting of platinum (Pt), palladium (Pd), ruthenium (Ru), iron (Fe), nickel (Ni), cobalt (Co) and molybdenum (Mo) and the content of the active metal component is 0.1-30 wt %, specifically 0.5-10 wt %, based on the multi-level pore zeolite.

20. The catalyst for hydroisomerization of normal paraffins according to claim 18, wherein the catalyst for hydroisomerization of normal paraffins is used to obtain isoparaffins through hydroisomerization of hydrocarbon materials such as diesel or lube base oil.

21. A hydroisomerization method which is performed for hydrocarbon materials such as diesel or lube base oil at a reaction temperature of 200-400 C., a hydrogen pressure of 1-200 atm, a liquid space velocity of 1-8 h.sup.1 and a hydrogen consumption rate of 500-12,000 scf/B in the presence of the catalyst for hydroisomerization of normal paraffins according to claim 18.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0028] FIG. 1 shows the XRD spectra of zeolites prepared in examples and a comparative example.

[0029] FIG. 2 shows the SEM images of zeolites prepared in examples and a comparative example.

[0030] FIG. 3 shows the TEM images of zeolites prepared in examples and a comparative example.

[0031] FIG. 4 shows a result of conducting hydroisomerization of n-dodecane using catalysts for hydroisomerization of normal paraffins prepared in examples and a comparative example and analyzing the produced isoparaffins by gas chromatography.

[0032] FIG. 5 shows a result of conducting hydroisomerization of n-dodecane using catalysts for hydroisomerization of normal paraffins prepared in examples and a comparative example.

[0033] FIG. 6 shows a result of conducting hydroisomerization of n-dodecane using catalyst for hydroisomerization of normal paraffins synthesized using zeolites prepared in examples and a comparative example as supports. The amounts of mono-branched isomers, multi-branched isomers including di-branched isomers and cracking products are shown as functions of a conversion rate.

[0034] FIG. 7 shows a result of comparing a relationship between the outer surface area of zeolites prepared in examples and a comparative example obtained through nitrogen physisorption analysis and (the amount of external Brnsted acid sites/the amount of total Brnsted acid sites100) obtained through FT-IR analysis using pyridine and 2,6-di-t-butylpyridine as a function of reaction yield in hydroisomerization of n-dodecane conducted using the catalysts for hydroisomerization of normal paraffins.

[0035] FIG. 8 shows a result of analyzing a liquid material corresponding to diesel, which is used in hydroisomerization, by gas chromatography.

[0036] FIG. 9 shows a result of conducting hydroisomerization of a liquid material corresponding to diesel using a catalyst for hydroisomerization of normal paraffins synthesized using a multi-level pore zeolite prepared according to an exemplary embodiment of the present disclosure as a support and analyzing the obtained liquid product by gas chromatography.

BEST MODE

[0037] The present disclosure relates to a method for preparing a multi-level pore zeolite, which exhibits an improved isoparaffin yield and high hydroisomerization reactivity when used as a catalyst, and a utilization of a multi-level pore zeolite prepared thereby as a catalyst for hydroisomerization of normal paraffins.

[0038] The multi-level pore zeolite of the present disclosure is SAPO-11 having a 1-dimensional channel structure. It has the aluminophoshate-11 (AEL) structure and has additional mesopores.

[0039] Multi-level porosity means that mesopores and micropores are present at the same time and are arranged regularly.

[0040] Hereinafter, the present disclosure is described in detail.

[0041] A method for preparing a multi-level pore zeolite of the present disclosure includes: (A) a step of mixing a silicon precursor, an aluminum precursor, a phosphorus precursor, a structure directing agent and water; a step of (B) adding phenylphosphonic acid, carbon black or a mixture thereof to the mixture prepared in the step (A) and mixing the same; a step of (C) crystallizing the mixture prepared in the step (B) by heat-treating the same and then cooling to room temperature; and a step of (D) calcining the cooled crystallization product.

[0042] First, in the step (A), a silicon precursor, an aluminum precursor, a phosphorus precursor, a structure directing agent and water are mixed.

[0043] The silicon precursor may be one or more selected from a group consisting of silica sol, fumed silica, tetraethyl orthosilicate and tetrapropyl orthosilicate.

[0044] The aluminum precursor may be aluminum isopropoxide, pseudoboehmite or a mixture thereof.

[0045] The phosphorus precursor may be phosphoric acid (H.sub.3PO.sub.4), phosphorous acid (H.sub.3PO.sub.3) or a mixture thereof.

[0046] And, the structure directing agent may be one or more selected from a group consisting of dipropylamine, triethylamine, tripropylamine, dibutylamine and heptylamine.

[0047] A molar ratio of aluminum (Al.sub.2O.sub.3)/silicon (SiO.sub.2) is 2-20, specifically 4-15. When the molar ratio of aluminum (Al.sub.2O.sub.3)/silicon (SiO.sub.2) is outside this range, a zeolite having a structure other than the AEL structure may be formed.

[0048] Next, in the step (B), a gel-type mixture is prepared by adding phenylphosphonic acid, carbon black or a mixture thereof to the mixture prepared in the step (A) and mixing at 23-27 C. The phenylphosphonic acid, the carbon black or a mixture thereof may be either added to the mixture prepared in the step (A) or mixed with the materials in the step (A).

[0049] As the phenylphosphonic acid, the carbon black or a mixture thereof is added to the mixture prepared in the step (A), mesopores and micropores of various sizes may be formed in the zeolite. The pores formed in the zeolite have an average diameter of 1-50 nm. Among them, micropores having a diameter of 0.1-1.9 nm are included in an amount of 10-30 vol % based on the volume of the total pores, mesopores having a diameter of 2.0-50.0 nm are included in an amount of 30-70 vol % based on the volume of the total pores and macropores having a diameter of 50.1-60.0 nm are included in an amount of 5-20 vol % based on the volume of the total pores.

[0050] When the phenylphosphonic acid, the carbon black or a mixture thereof is not added, low isoparaffin yield and hydroisomerization reactivity are achieved because mesopores and micropores of various sizes, particularly mesopores having a particle diameter of 10-30 nm, are not formed in large amounts.

[0051] When the phenylphosphonic acid is added alone, a molar ratio of the water/phenylphosphonic acid is 45.5-1,000, specifically 50-500; a molar ratio of the structure directing agent/phenylphosphonic acid is 0.9-38.0, specifically 1.3-20; a molar ratio of the phosphorus precursor/phenylphosphonic acid is 1.8-40.0, specifically 1.8-25; and a molar ratio of total phosphorus (P.sub.2O.sub.5) contained in the phosphorus precursor and phenylphosphonic acid/aluminum (Al.sub.2O.sub.3) is 1.0-1.6, specifically 1.2-1.5. If the molar ratios are outside the above ranges, mesopores of various sizes may not be formed sufficiently or pores having a size of 10-30 nm may not be formed in large quantities. And, if the molar ratios are quite distant from these ranges, zeolites other than the AEL zeolite having a 1-dimensional structure and having pores, each of which consists of 10 atoms, and having a size of 0.40-0.65 nm may be formed.

[0052] The amount of the carbon black is not particularly limited as long as it can be removed during calcining. Specifically, when the carbon black is added alone, it is added in an amount of 1-250 parts by weight based on 100 parts by weight of the multi-level pore zeolite and a weight ratio of the structure directing agent/carbon black is 0.5-50, specifically 1-40. If the content of the carbon black is outside the above range, mesopores of various sizes may not be formed sufficiently or pores having a size of 10-30 nm may not be formed in large quantities. And, if the weight ratio is quite distant from the above range, it may be difficult to form the multi-level pore zeolite of the present disclosure having the AEL structure.

[0053] When a mixture of the phenylphosphonic acid and the carbon black is added, a molar ratio of the water/phenylphosphonic acid is 45.5-1,000, specifically 50-500; a molar ratio of the structure directing agent/phenylphosphonic acid is 0.9-46.0, specifically 1.5-30; a molar ratio of the phosphorus precursor/phenylphosphonic acid is 1.8-40.0, specifically 1.8-25; and a molar ratio of total phosphorus (P.sub.2O.sub.5) contained in the phosphorus precursor and phenylphosphonic acid/aluminum (Al.sub.2O.sub.3) is 1.0-1.6, specifically 1.2-1.5. And, the carbon black is added in an amount of 1-250 parts by weight based on 100 parts by weight of the multi-level pore zeolite. If the molar ratio and the content of the carbon black are outside the above ranges, the same problems may occur as when the phenylphosphonic acid or the carbon black is used alone.

[0054] Next, in the step (C), the gel-type mixture prepared in the step (B) is crystallized to a zeolite by heat-treating the same and then cooled to room temperature.

[0055] The crystallization is performed at 150-200 C. for 24-168 hours. Specifically, it is performed at 150-200 C. for 24-72 hours when the phenylphosphonic acid is used alone and is performed at 150-200 C. for 24-168 hours when the carbon black alone or a mixture of the phenylphosphonic acid and the carbon black is used.

[0056] Next, in the step (D), the crystallized zeolite is calcined to improve the performance of the zeolite. Through the calcining, the structure directing agent, the benzyl group of the phenylphosphonic acid, the carbon black are removed, water inside the pores is completely removed and the thermal and mechanical durability of the zeolite are improved.

[0057] Specifically, the calcining is performed at 400-700 C. for 8-15 hours.

[0058] The prepared multi-level pore zeolite has pores having an average diameter of 1-50 nm. Among them, micropores having a diameter of 0.1-1.9 nm are included in an amount of 10-30 vol % based on the volume of the total pores, mesopores having a diameter of 2.0-50.0 nm are included in an amount of 50-70 vol % based on the volume of the total pores and macropores having a diameter of 50.1-60.0 nm are included in an amount of 5-20 vol % based on the volume of the total pores. In particular, among the mesopores having a diameter of 2.0-50.0 nm, those having a diameter of 10-30 nm are included in an amount of 30-40 vol % based on the volume of the total pores. When the prepared multi-level pore zeolite is used as a support for a catalyst for hydroisomerization of normal paraffins, high isoparaffin yield and superior hydroisomerization reactivity are achieved.

[0059] Further, a catalyst for hydroisomerization of normal paraffins may be prepared by including a step of supporting an active metal component on the multi-level pore zeolite and calcining the same. The active metal component may be one or more selected from a group consisting of platinum (Pt), palladium (Pd), ruthenium (Ru), iron (Fe), nickel (Ni), cobalt (Co) and molybdenum (Mo).

[0060] The content of the active metal component is 0.1-30 wt %, specifically 0.5-10 wt %, based on the multi-level pore zeolite.

MODE FOR INVENTION

[0061] Hereinafter, the present disclosure will be described in detail through specific examples. However, the following examples are for illustrative purposes only and it will be apparent to those of ordinary skill in the art that the scope of the present disclosure is not limited by the examples.

Example 1. Preparation of Multi-Level Pore Zeolite Using Phenylphosphonic Acid

[0062] A gel was prepared by stirring tetraethyl orthosilicate (Si(OC.sub.2H.sub.5).sub.4, 98%, Aldrich), aluminum isopropoxide (Al(i-OPr).sub.3, 98%, Aldrich), phosphoric acid (H.sub.3PO.sub.4, 85 wt % in H.sub.2O, Junsei), dipropylamine (C.sub.6H.sub.15N, >99%, TCI), phenylphosphonic acid (C.sub.6H.sub.7O.sub.3P, 98%, Aldrich) and water at room temperature (25 C.), crystallized in a stainless steel autoclave at 170 C. for 48 hours and then cooled to room temperature. The cooled crystallization product was filtered, washed several times with distilled water, dried at 100 C. and then calcined at 600 C. for 10 hours to prepare a multi-level pore zeolite.

[0063] The multi-level pore zeolite had a molar ratio of water/phenylphosphonic acid of 55.6, a molar ratio of dipropylamine/phenylphosphonic acid of 1.4, a molar ratio of phosphoric acid/phenylphosphonic acid of 2.2 and a molar ratio of total phosphorus contained in phosphoric acid and phenylphosphonic acid (P.sub.2O.sub.5)/aluminum (Al.sub.2O.sub.3) of 1.4. The composition of the prepared multi-level pore zeolite was as follows.

[0064] 1.0Al.sub.2O.sub.3:1.0P.sub.2O.sub.5:1.3DPA:0.2SiO.sub.2:50H.sub.2O:0.9C.sub.6H.sub.7O.sub.3P

Example 2. Preparation of Multi-Level Pore Zeolite Using Carbon Black

[0065] A multi-level pore zeolite was prepared in the same manner as in Example 1, except that carbon black was used instead of phenylphosphonic acid and crystallization was performed at 185 C. for 120 hours.

[0066] The carbon black was added in an amount of 100 parts by weight based on 100 parts by weight of the multi-level pore zeolite and a weight ratio of dipropylamine/carbon black was 0.6. The composition of the prepared multi-level pore zeolite was as follows.

[0067] 1.0Al.sub.2O.sub.3:1.0P.sub.2O.sub.5:1.4DPA:0.2SiO.sub.2:50H.sub.2O:100carbon black

Example 3. Preparation of Multi-Level Pore Zeolite Using Phenylphosphonic Acid and Carbon Black

[0068] A multi-level pore zeolite was prepared in the same manner as in Example 1, except that a mixture of phenylphosphonic acid and carbon black was used instead of phenylphosphonic acid and crystallization was performed at 185 C. for 120 hours.

[0069] The multi-level pore zeolite had a molar ratio of water/phenylphosphonic acid of 55.6, a molar ratio of dipropylamine/phenylphosphonic acid of 2.1, a molar ratio of phosphoric acid/phenylphosphonic acid of 2.2 and a molar ratio of total phosphorus contained in phosphoric acid and phenylphosphonic acid (P.sub.2O.sub.5)/aluminum (Al.sub.2O.sub.3) of 1.4. The composition of the prepared multi-level pore zeolite was as follows.

[0070] 1.0Al.sub.2O.sub.3:1.0P.sub.2O.sub.5:1.9DPA:0.2SiO.sub.2:50H.sub.2O:0.9C.sub.6H.sub.7O.sub.3P:100carbon black

Comparative Example 1

[0071] A general SAPO-11 zeolite with no phenylphosphonic acid was prepared as in Example 1, with the composition of dipropylamine as 1.2. The zeolite was synthesized by crystallizing at 185 C. for 48 hours. The composition of the prepared zeolite was as follows.

[0072] 1.0Al.sub.2O.sub.3:1.0P.sub.2O.sub.5:1.2DPA:0.2SiO.sub.2:50H.sub.2O

Test Example 1. XRD, SEM, TEM, Nitrogen (N.SUB.2.) Physisorption and IR Measurements

[0073] FIG. 1 shows the XRD spectra of the multi-level pore zeolites prepared in the examples and the zeolite prepared in the comparative example, FIG. 2 shows the SEM images of the multi-level pore zeolites prepared in the examples and the zeolite prepared in the comparative example and FIG. 3 shows the TEM images of the multi-level pore zeolites prepared in the examples and the zeolite prepared in the comparative example.

[0074] As seen from FIGS. 1-3, the multi-level pore zeolites prepared in Examples 1-3 were AEL zeolites having mesopores and micropores with different sizes. In contrast, the zeolite prepared in Comparative Example 1 had micropores only.

[0075] In FIG. 2, the magnification of SEM was 25,000 for Example 1, 25,000 for Example 2, 35,000 for Example 3 and 12,000 for Comparative Example 1.

[0076] Nitrogen (N.sub.2) physisorption analysis was conducted to measure the outer surface area of the multi-level pore zeolites prepared in the examples and the zeolite prepared in the comparative example. 0.1 g of the zeolites prepared in the examples and the comparative example were pretreated at 400 C. for 4 hours in vacuum and nitrogen was adsorbed at 196 C. The amount of adsorbed nitrogen gas was measured and the outer surface area of the zeolites was obtained using the t-plot method. The result is shown in Table 1 as S.sub.ext (m.sup.2/g).

[0077] In addition, FT-IR analysis was conducted using pyridine and 2,6-di-t-butylpyridine as adsorbates in order to measure the amount of total acid sites and external acid sites of the multi-level pore zeolites prepared in the examples and the zeolite prepared in the comparative example.

[0078] The multi-level pore zeolites prepared in the examples and the zeolite prepared in the comparative example were prepared into circular pellets with a weight of 15 mg and a diameter of 13 mm and pretreated at 450 C. for 4 hours in an IR cell in vacuum. After the pretreatment, background data were obtained by cooling to room temperature and then pyridine or 2,6-di-t-butylpyridine vapor was adsorbed in-situ at room temperature for 2 hours. Then, after desorbing the physisorbed and weakly adsorbed pyridine or 2,6-di-t-butylpyridine at 150 C. for 2 hours, IR analysis was conducted after cooling to room temperature. Finally, area value was calculated by subtracting the background data from the desorption data obtained at 150 C. For quantitative analysis, the molar extinction coefficient values were set to 5.98 cm mol.sup.1 for pyridine and 10.10 cm mol.sup.1 for 2,6-di-t-butylpyridine.

[0079] The result of quantitative analysis based on FT-IR is shown in [Table 1].

TABLE-US-00001 TABLE 1 Acidity (mol/g) External Total Brnsted Accessi- Accessi- Brnsted acid sites bility bility acid sites (2,6- S.sub.ext factor factor (Py-IR) DTBPy-IR) (m.sup.2/g) (%) (%)/S.sub.ext Comparative 169 46.3 50 27 0.55 Example 1 Example 1 170 32.5 50 19 0.38 Example 2 186 43.6 80 23 0.29 Example 3 132 25.8 70 20 0.28

[0080] As seen from Table 1, the multi-level pore zeolites prepared in Examples 1-3 according to the present disclosure showed lower accessibility factor (%) than the zeolite of Comparative Example 1. Also, the accessibility factor (%)/S.sub.ext values were lower for Examples 1-3 than for Comparative Example 1.

[0081] The S.sub.ext means the outer surface area and the accessibility factor (%) is the value of the amount of external Brnsted acid site/the amount of total Brnsted acid sites100.

Test Example 2. Measurement of Hydroisomerization Reactivity for Normal Paraffins

[0082] Preparation of Supported Catalyst

[0083] After supporting platinum by incipient wetness impregnation using aqueous solutions containing the zeolite powders prepared in Examples 1-3 and Comparative Example 1 and a platinum precursor and drying in an oven at 100 C. for 4 hours or longer, platinum-supported catalysts for hydroisomerization of normal paraffins were obtained by calcining the dried powder samples at 400 C. for 3 hours under a dry air atmosphere. The loading amount of the supported platinum was 1 wt % based on the support.

[0084] As the platinum precursor, Pt(NH.sub.3).sub.4(NO.sub.3).sub.2 or Pt(NH.sub.3).sub.4Cl.sub.2xH.sub.2O can be used. In the present disclosure, Pt(NH.sub.3).sub.4(NO.sub.3).sub.2 was used as the platinum precursor.

[0085] Measurement of Hydroisomerization Reactivity

[0086] Hydroisomerization was conducted using the catalyst for hydroisomerization of normal paraffins prepared using the zeolites of the examples and the comparative example for preparing isoparaffins from normal paraffins corresponding to diesel or lube base oil.

[0087] In general, the hydroisomerization is conducted at a reaction temperature of 200-400 C. with a hydrogen pressure of 1-200 atm. For example, the reaction temperature may be 280-350 C. and the hydrogen pressure may be 5-30 atm. Before conducting the reaction, the catalysts were compressed into circular discs, cut to a size of 150-200 mm, loaded into a stainless steel fixed-bed continuous flow reactor with an inner diameter of inch and then reduced at 400 C. in-situ under a hydrogen atmosphere. The reaction was conducted using n-dodecane (C.sub.12H.sub.26, TCI) as a typical reactant with a space velocity of 2-8 h.sup.1 and a hydrogen consumption rate of 500-12,000 scfb/B.

[0088] The products were analyzed by off-line gas chromatography. The analysis was conducted by maintaining temperature at 40 C. for 5 minutes and then increasing to 250 C. at a rate of 0.5 C./min. In FIG. 4, the area of the region of 18-32 minutes was calculated as that of multi-branched isomers including di-branched isomers and the area of the region of 32-38 minutes was calculated as that of mono-branched isomers. The proportion of the multi-branched isomers including di-branched isomers to the produced isoparaffins was calculated from the proportion of the area of the multi-branched isomers including di-branched isomers to that of the produced isoparaffins.

[0089] The conversion of n-dodecane was calculated from

[00001]$\frac{{\left(n-C_{12}.Math.\mathrm{mol}\right)}_{\mathrm{in}}-{\left(n-C_{12}.Math.\mathrm{mol}\right)}_{\mathrm{out}}}{{\left(n-C_{12}.Math..Math.\mathrm{mol}\right)}_{\mathrm{in}}}100$

and the yield of dodecane isomers was calculated from

[00002]$\frac{{\left(\mathrm{iso}-C_{12}.Math.\mathrm{mol}\right)}_{\mathrm{out}}}{{\left(n-C_{12}.Math.\mathrm{mol}\right)}_{\mathrm{in}}}100.$

When the hydroisomerization was conducted using n-dodecane as the reactant, the yield of dodecane isomers was 44% at maximum when the catalyst for hydroisomerization of normal paraffins of Comparative Example 1 was used and was 70% at maximum when the catalyst for hydroisomerization of normal paraffins of Example 1 was used, as can be seen from FIG. 5. When the catalyst for hydroisomerization of normal paraffins of Example 2 was used the maximum yield of dodecane isomers was 85%, and when the catalyst for hydroisomerization of normal paraffins of Example 3 was used the maximum yield of dodecane isomers was also 85%. It is thought that the isoparaffin yield was increased because the residence time of the reactant in the zeolite crystals during the hydroisomerization was decreased due to the mesopores additionally formed in the multi-level pore zeolites and, thus, hydrocracking was inhibited. Also, it is thought that the isoparaffin yield was increased because nonselective hydrocracking that may occur on the outer surface of the zeolites was inhibited because the multi-level pore zeolites prepared in Examples 1-3 have less external acid sites among the total acid sites as compared to the zeolite prepared in Comparative Example 1, as can be seen from [Table 1] in Test Example 1.

[0090] Among the isomers produced through the hydroisomerization, the multi-branched isomers including di-branched isomers can improve the flow characteristics of liquid fuel because they have lower pour point or cloud point than the mono-branched isomers. The result of conducting the hydroisomerization of n-dodecane using the catalysts for hydroisomerization of normal paraffins prepared in the comparative example and the examples and investigating the yields of mono-branched isomers and multi-branched isomers including di-branched isomers in the produced dodecane isomers is shown in FIG. 6.

[0091] As seen from FIG. 6, when the catalyst for hydroisomerization of normal paraffins of Comparative Example 1 was used, the maximum isoparaffin yield was 40% and the yield of multi-branched isomers including di-branched isomers was 7%. When the catalyst for hydroisomerization of normal paraffins of Example 1 was used, the maximum isoparaffin yield was 70% and the yield of multi-branched isomers including di-branched isomers was about 25%. When the catalyst for hydroisomerization of normal paraffins of Example 2 was used, the maximum isoparaffin yield was 85% and the yield of multi-branched isomers including di-branched isomers was 39%. And, when the catalyst for hydroisomerization of normal paraffins of Example 3 was used, the maximum isoparaffin yield was 85% and the yield of multi-branched isomers including di-branched isomers was 34%. The proportion of the yield of multi-branched isomers including di-branched isomers to the maximum isoparaffin yield was 17.5% when the catalyst for hydroisomerization of Comparative Example 1 was used and about 36% when the catalyst for hydroisomerization of Example 1 was used. The proportion of the yield of multi-branched isomers including di-branched isomers to the maximum isoparaffin yield was about 46% when the catalyst for hydroisomerization of Example 2 was used and about 39% when the catalyst for hydroisomerization of Example 3 was used. In particular, when the catalyst for hydroisomerization of Example 3 was used, the yield of multi-branched isomers including di-branched isomers was increased to 42% when the conversion rate was 95% and the isoparaffin yield was 81%. In this case, the proportion of the yield of multi-branched isomers including di-branched isomers to the isoparaffin yield was about 52%.

[0092] Through this, it can be seen that the catalysts for hydroisomerization of normal paraffins prepared from the zeolites of Examples 1-3, which has additionally formed mesopores and has fewer external acid sites among the total acid sites as compared to that prepared from the zeolite of Comparative Example 1, which has micropores only, exhibits superior isoparaffin yield and yield of multi-branched isomers including di-branched isomers.

[0093] The relationship between dodecane isomer yields and the ratio of accessibility factor (%) over outer surface area of the zeolite obtained from the FT-IR and N.sub.2 physisorption (Test Example 1) is shown in FIG. 7. In FIG. 7, the accessibility factor (%) represents the proportion of external acid sites/total acid sites. It can be seen that the yield of dodecane isomers increases as the amount of external acid sites of the synthesized zeolite is smaller and the amount of outer surface area is larger. This suggests that the dodecane isomers produced through the hydroisomerization inhibit nonselective hydrocracking on the outer surface of the zeolite and the additionally formed mesopores inhibit hydrocracking by reducing the residence time in the zeolite crystals, thereby increasing the yield of the isomers.

Test Example 3. Measurement of Hydroisomerization Reactivity for Liquid Paraffins Corresponding to Diesel

[0094] Hydroisomerization was conducted for a feed sample corresponding to diesel using the catalyst for hydroisomerization of normal paraffins prepared from the zeolite of Example 3. The carbon distribution of the sample is shown in [Table 2] and the result of analyzing the sample by gas chromatography is shown in FIG. 8.

TABLE-US-00002 TABLE 2 C.sub.10 C.sub.11 C.sub.12 C.sub.13 C.sub.14 C.sub.15 C.sub.16 C.sub.17 C.sub.18 C.sub.19 C.sub.20 C.sub.21 C.sub.22 C.sub.23 C.sub.24 C.sub.25 C.sub.26 C.sub.27 C.sub.28 Mol % 1.8 3.1 5.5 8.2 11.1 12.2 11.6 11.3 9.3 7.8 5.0 4.0 3.0 2.3 1.6 1.0 0.6 0.3 0.2

[0095] As seen from Table 2, 89% or more of the feed sample corresponding to diesel was hydrocarbons with a chain length of 12-22 and most of the hydrocarbons were normal paraffins (FIG. 8).

[0096] Hydroisomerization was conducted for the feed sample corresponding to diesel using the catalyst for hydroisomerization of normal paraffins prepared from the zeolite of Example 3 at different reaction temperatures. The result is shown in [Table 3].

TABLE-US-00003 TABLE 3 Reaction temperature Diesel feed sample 267 C. 273 C. 278 C. 287 C. Conversion rate (%) 47.5 53.0 67.4 78.6 Liquid yield (%) 99.3 98.4 96.6 94.5 Cloud point ( C.) 1 22 27 35 52 Pour point ( C.) 8 26 30 42 55 or lower Sulfur content (ppm) 8 1 or less 1 or less 1 or less 1 or less Total aromatic content 23.2 10.0 10.9 7.4 4.5 (%) Aromatic Mono 20.1 9.8 10.7 7.2 4.3 structure Di 2.8 0.2 0.2 0.2 0.2 Tri 0.3 Not Not Not Not detected detected detected detected Distillation Initial 227 197 203 191 173 test ( C.) boiling point (IBP) 5% boiling 246 235 237 231 218 point 10% boiling 254 248 250 245 233 point 30% boiling 272 268 269 266 259 point 50% boiling 289 284 285 282 277 point 70% boiling 307 303 303 301 295 point 90% boiling 337 334 334 332 325 point 95% boiling 349 348 347 345 337 point End point 365 365 364 362 352 (EP)

[0097] Hydroisomerization was conducted using the catalyst for hydroisomerization of normal paraffins at different reaction temperatures as seen from Table 3. The products were analyzed by offline gas chromatography. The analysis condition was the same as in Test Example 2. The conversion rate of the diesel feed sample was calculated as the fraction of normal paraffins with carbon chain lengths of 12-22 after the reaction. The liquid yield was calculated as the ratio of the mass of actually collected liquid to the theoretical value. When the hydroisomerization was conducted for the diesel feed sample with a cloud point of 1 C. and a pour point of 8 C. at a hydrogen pressure of 20 atm, a space velocity of 2 h.sup.1, a hydrogen gas pressure of 20 mol/mol and a reaction temperature 267-287 C. using the prepared catalyst for hydroisomerization of normal paraffins, significantly improved products with a cloud point of 22 to 52 C. and a pour point of 26 to 55 C. could be obtained. The catalyst for hydroisomerization of normal paraffins showed inhibited nonselective hydrocracking and improved isomer yield due to the decreased external acid sites in the multi-level pore zeolite used as the support and due to the mesopores present in the multi-level pore zeolite. As a result, the products could be obtained with a high yield of 94.5-99.3%.

[0098] Also, it was confirmed that the cloud point, pour point, sulfur content, total aromatic content, etc. decreased as the conversion rate increased. In addition, it was confirmed that as the conversion rate increased the initial boiling point (IBP) decreased and most of the produced aromatics had monoaromatic structures.

[0099] The conversion rate means the ratio of the normal paraffins that were converted to isoparaffins or other materials. And, the boiling point expressed with the percentage value, e.g., 5% boiling point, means the temperature at which 5% of the liquid fuel is vaporized.

[0100] Also, as seen from FIG. 9, it was confirmed that the proportion of isoparaffins to normal paraffins was higher for the hydrocarbons with carbon chain length of 12 or larger.

[0101] In addition, hydroisomerization of a diesel feed sample was conducted using the catalyst for hydroisomerization of normal paraffins prepared from the zeolite of Example 2 at different reaction temperatures. The result is shown in [Table 4].

TABLE-US-00004 TABLE 4 Reaction temperature Diesel feed sample 246 C. 257 C. 267 C. 277 C. Conversion rate (%) 11.4 24.9 36.2 53.1 Liquid yield (%) 99.8 99.6 99.8 99.6 Cloud point ( C.) 1 3 8 16 27 Pour point ( C.) 8 10 14 21 31 Sulfur content (ppm) 8 1 or less 1 or less 1 or less 1 or less Total aromatic content 23.2 8.4 7.6 6.5 6.2 (%) Aromatic Mono 20.1 8.4 7.6 6.5 6.2 structure Di 2.8 Not Not Not Not detected detected detected detected Tri 0.3 Not Not Not Not detected detected detected detected Distillation Initial 227 202 201 201 194 test ( C.) boiling point (IBP) 5% boiling 246 234 233 233 229 point 10% boiling 254 245 244 244 242 point 30% boiling 272 265 265 265 263 point 50% boiling 289 284 283 283 281 point 70% boiling 307 303 302 301 299 point 90% boiling 337 334 333 333 331 point 95% boiling 349 348 347 347 345 point End point 365 362 362 362 360 (EP)

[0102] As seen from Table 4, when the hydroisomerization was conducted for the feed with a cloud point of 1 C. and a pour point of 8 C. at a hydrogen pressure of 20 atm, a space velocity of 2 h.sup.1, a hydrogen gas pressure of 20 mol/mol and a reaction temperature 246-277 C. using the prepared catalyst for hydroisomerization of normal paraffins, significantly improved products with a cloud point of 3 to 27 C. and a pour point of 10 to 31 C. could be obtained, as when the catalyst for hydroisomerization of normal paraffins prepared using the zeolite of Example 3 was used. The catalyst for hydroisomerization of normal paraffins showed inhibited nonselective hydrocracking and improved isomer yield due to the decreased external acid sites in the multi-level pore zeolite used as the support and due to the mesopores present in the multi-level pore zeolite. As a result, the products could be obtained with a high yield of 99.6-99.8%.

[0103] Also, it was confirmed that the cloud point, pour point, sulfur content, total aromatic content, etc. decreased as the conversion rate increased. In addition, it was confirmed that as the conversion rate increased the initial boiling point (IBP) decreased and most of the produced aromatics had monoaromatic structures. In particular, it was confirmed that the liquid yield was maintained at 99.6% or higher although the conversion rate was 53.1% and the cloud point and the pour point were decreased to 27 C. and 31 C., respectively.

INDUSTRIAL APPLICABILITY

[0104] A catalyst which is prepared by supporting a metal on a multi-level pore zeolite of the present disclosure can effectively improve cloud point and pour point when used as a catalyst for hydroisomerization of normal paraffins and thus can be used as a catalyst for hydroisomerization of normal paraffins such as diesel or lube base oil.