HYDROISOMERIZATION CATALYST

Abstract

The present disclosure relates to a precursor for a catalytically active material or a catalytically active material comprising platinum, a molecular sieve and a metal oxide support, characterized in at least 80%, 90% or 95% of said platinum being dispersed on said molecular sieve and at least 80%, 90% or 95% of said platinum being dispersed in clusters having a size below 2 nm or 1 nm, as well as a method of producing such materials and process for hydroisomerization involving such materials. The disclosure has the associated benefit of such a catalytically active material being highly active and selective towards hydroisomerization.

Claims

1. A precursor for a catalytically active material or a catalytically active material comprising platinum, a molecular sieve and a metal oxide support, wherein at least 80% of said platinum being dispersed on said molecular sieve and at least 80% of said platinum being dispersed in clusters having a size below 2 nm.

2. A precursor for a catalytically active material or a catalytically active material comprising platinum, a molecular sieve and a metal oxide support, wherein platinum being dispersed such that at least 80% of the platinum surface area is found in clusters on said molecular sieve and further wherein platinum being dispersed such that at least 80% of the platinum surface area is found in clusters in clusters having a size below 2 nm.

3. A precursor for a catalytically active material or a catalytically active material comprising platinum, a molecular sieve and a metal oxide support, wherein platinum being dispersed such that at least 80% of the platinum mass is found in clusters on said molecular sieve and further wherein platinum being dispersed such that at least 80% of the platinum mass is found in clusters in clusters having a size below 2 nm.

4. The precursor for a catalytically active material or a catalytically active material according to claim 1, further comprising at least 0.5 wt % carbon.

5. The precursor for a catalytically active material or a catalytically active material according to claim 4, comprising at least 1 wt % organic additive or compounds derived herefrom.

6. The precursor for a catalytically active material or a catalytically active material according to claim 1, wherein said metal oxide support is taken from the group comprising alumina, silica, silica-alumina and titania.

7. The precursor for a catalytically active material or a catalytically active material according to claim 1, wherein said molecular sieve being one or more materials taken from the group having AEI, AEL, AFO, AFX, ATO, BEA, CHA, FAU, FER, MEL, MFI, MOR, MRE, MTT, MWW or TON topology.

8. The precursor for a catalytically active material or a catalytically active material according to claim 1, wherein said molecular sieve is EU-2, and wherein said molecular sieve has a silica to alumina ratio from 50 to 200.

9. A method for producing a precursor for a catalytically active material involving the steps of: a) forming a support paste by combining alumina with a molecular sieve b) extruding or pelletizing said support paste, forming support particles, c) impregnating said support particles by incipient wetness impregnation with a solution of platinum salt comprising an organic additive such as citric acid, lactic acid or formic acid, providing catalyst precursor d) drying said catalyst precursor at a temperature of 120 C. to 200 C. in air

10. A method for producing a catalytically active material from a precursor according to claim 1, in which said precursor is contacted with a flow of a reductant such as hydrogen at a temperature between 150 C. and 350 C.

11. A process for dewaxing a hydrocarbon or a hydrocarbon mixture involving directing said hydrocarbon or hydrocarbon mixture to contact a catalytically active material produced according to claim 10 in the presence of hydrogen under dewaxing conditions.

Description

EXAMPLES

[0042] Two examples of catalytically active material were synthesized. Catalyst 1 was produced according to the present invention and catalyst 2 was produced according to the prior art, in accordance with U.S. Pat. No. 6,984,309.

Example 1

[0043] Catalyst 1:

[0044] A commercial EU-2 zeolite with a silica to alumina ratio (SAR) of 155 was mixed with an alumina gel that is peptized by nitric acid and alumina powder, in a ratio to give a final composition of the extrudates on a dry basis of 65 wt % zeolite and 35 wt % alumina. The paste that is thus obtained is run through a die plate that has cylindrical openings with a diameter of 1.86 mm. The extrudates are then dried for one night at 120 C. and then calcined at 500 C. under air for 2 hours. Onto this substrate is deposited by incipient wetness impregnation an aqueous solution of citric acid and Pt(NH.sub.3).sub.4.sup.2+, 2HCO.sub.3.sup., such that the content of platinum deposited on the substrate is ultimately 0.5% by weight after decomposition at 600 C., the citric acid concentration being 0.6 M. The extrudates are then dried under air at 150 C. This preparation produces a fully impregnated catalyst for which the Pt is located on the EU-2 zeolite.

[0045] Catalyst 2:

[0046] A commercial EU-2 zeolite with a silica to alumina ratio (SAR) of 155 was mixed with an alumina gel that is peptized by nitric acid and alumina powder, in a ratio to give a final composition of the extrudates on a dry basis of 65 wt % zeolite and 35 wt % alumina. The paste that is thus obtained is run through a die plate that has cylindrical openings with a diameter of 1.86 mm. The extrudates are then dried for one night at 120 C. and then calcined at 500 C. under air for 2 hours. Onto this substrate is deposited by incipient wetness impregnation an aqueous solution of ammonia and Pt(NH.sub.3).sub.4.sup.2+, 2HCO.sub.3, such that the content of platinum deposited on the substrate is ultimately 0.5% by weight after decomposition at 600 C., the ammonia concentration being 0.15 M. The extrudates are then decomposed under air at 310 C. This preparation produces a shell impregnated catalyst for which the Pt is located both on the alumina and the EU-2 zeolite.

[0047] Catalysts 1 and 2 were analyzed by TEM and SEM, and the results are reported in Table 1. It can be seen that Catalyst 1 produced in accordance with the present disclosure is characterized by distribution of platinum in the full volume of the extrudates (no shell impregnation), absence of platinum on the alumina, and that the cluster size of noble metal is below 1 nm, whereas Catalyst 2 produced in accordance with the prior art has significantly larger clusters; up to 15 nm, the platinum is distributed in a shell layer close to the external surface of the extrudates, and the platinum is found on the alumina and on the zeolite. In addition, Catalyst 1 comprises 2% carbon, which is assumed to be in the form of citric acid or compounds derived herefrom.

Example 2

[0048] A hydro-deoxygenated corn oil was used as feed for hydroisomerization over the example catalysts. The characteristics of the feed are shown in Table 2.

[0049] The feed was directed to contact Catalysts 1 and 2 under a pressure of 50 barg, a temperature of 300 and 320 C., a LHSV of 2 h.sup.1, and a hydrogen to oil ratio of 500 NL/L. Key characteristics of the products are shown in Table 3.

[0050] Table 3 shows the effect of these differences in platinum distribution on performance of Catalyst 1 and Catalyst 2. It is seen that for similar conditions Catalyst 1 has a higher dewaxing activity, reflected by the higher cloud point improvement (CPI) at iso-temperature.

TABLE-US-00001 TABLE 1 Catalyst 1 Catalyst 2 Impregnation Uniform <200 m shell Platinum cluster size <1 nm <15 nm Platinum on alumina No Yes Platinum on zeolite Yes Yes Carbon 2% <0.1%

TABLE-US-00002 TABLE 2 Specific gravity 60/60 F. 0.8039 Nitrogen wt ppm 0.4 Sulfur wt ppm 9 Cloud point C. 24 Pour point C. 21 Aromatics Monoaromatics wt % 3.56 Diaromatics wt % 0.11 Tri+-aromatics wt % <0.05 Simulated distillation IBP C. 126.0 5 wt % C. 272.0 10 wt % C. 288.4 30 wt % C. 315.2 50 wt % C. 320.4 70 wt % C. 322.2 90 wt % C. 447.0 95 wt % C. 478.6 FBP C. 566.0

TABLE-US-00003 TABLE 3 Catalyst 1 Catalyst 2 300 C. 320 C. 300 C. 320 C. CPI C. 17.2 43.2 9.6 31.8 H.sub.2 Consumption NL/L 6 12 7 13