HIGHLY EFFICIENT ACID CATALYST FOR HYDROCARBON CONVERSION

Abstract

A mixed metal oxide solid acid catalyst composition is disclosed which provides substantially improved conversion for hydrocarbon transformation reactions namely, alkylation and isomerization. The catalyst composition includes a sulfate ion, Platinum group metal and a mixed metal oxide support material bearing molecular formula:

x.sub.1ZrO.sub.2.x.sub.2Al.sub.2O.sub.3.x.sub.3Yb.sub.2O.sub.3.x.sub.4CuO

wherein the molar coefficients for individual metal oxides are as follows:
x1=55 to 7510.sup.2; x2=12 to 2510.sup.2; x3=1 to 610.sup.2 and x4=0.1 to 510.sup.2;

The concentration of the sulfate ion on the aforementioned catalyst support is between 5 to 17 wt % and that of Platinum group metal is 0.05 to 2.0 wt %.

Claims

1. A method of converting hydrocarbons into high value products by isomerization and alkylation by contacting the reactants with a catalyst containing Group 3A, 4A, 11 and 8 elements along with Platinum group metals and sulfated ion, at optimized temperature and pressure conditions as desired for the hydrocarbon process, wherein the catalyst contains the following composition of metal oxides:
x.sub.1ZrO.sub.2.x.sub.2Al.sub.2O.sub.3.x.sub.3Yb.sub.2O.sub.3.x.sub.4CuO wherein the mole-coefficients for the individual oxides are as follows: x1=55 to 7510.sup.2; x2=12 to 2510.sup.2; x3=1 to 610.sup.2 and x4=0.1 to 510.sup.2; and the mass ratio of sulfated ion is between 5 to 17% and that of Platinum group metals is between 0.05 to 2%. a. a sulfated metal oxide (MOx) comprising sulfur in an amount ranging between 0.01 to 7 mole %, said metal oxide is at least one metal oxide selected from group consisting of zirconium oxide, aluminum oxide, ytterbium oxide and copper oxide. b. at least one lanthanide series element, specifically ytterbium, in a molar concentration ratio ((Lanthanide element:Zr) ranging between 0.01 to 2.35 mole %; c. at least one additional metal selected from the group consisting of Cu, Bi, Ti, Fe, Mn, Co and Ni in an amount ranging between 0.0 to 1.0 mole %, wherein each of said molar proportions being with respect to the total molar mass of final catalyst. d. at least one additional metal selected from the Platinum group metals including Ru, Re, Rh, Ir, Pd and/or Pt in an amount ranging between 0.05 to 2 wt % based on the final catalyst composition.

2. A method of hydrocarbon conversion according to claim 1, characterized by sulfur ion is present on the catalyst in the form of SO.sub.4.sup.2 or SO.sub.3.sup.2 ions.

3. A method of hydrocarbon conversion according to claim 1, wherein the overall weight percentage of the catalyst composition is as follows: TABLE-US-00003 r SO.sub.3.sup.2 ion % 8A metal 2% oxide support e to 100% indicates data missing or illegible when filed

4. A method of hydrocarbon conversion, specifically by isomerization according to claim 1, characterized in that the hydrogenating component of the catalyst use at least 2 metals from Group 8A of the periodic table comprising of Platinum, Palladium, Iridium, Rhodium and/or Ruthenium.

5. A method of hydrocarbon conversion according to the catalyst described in claim 1, wherein the isomerization process is conducted at a temperature range of 120 to 220 C., a pressure of 1.5 to 4.0 MPa and a hydrogen to hydrocarbon ratio of 1-10:1

6. A method of hydrocarbon conversion according the catalyst described in claim 1, wherein alkylation process is conducted at a temperature range of 90 to 240 C. depending on the hydrocarbon reactant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0019] In a first aspect, the present disclosure provides a sulfated mixed metal oxide based solid acid catalyst composition used for the catalytic conversion of hydrocarbons.

[0020] In accordance with one of the exemplary embodiments of the present disclosure, the sulfated zirconium oxide based solid catalyst composition comprises: [0021] i. Synthesis of high surface area Zirconium hydroxide support in the presence of sulfate, Ytterbium and Copper elements at temperatures less than 20 C. with controlled addition of base. [0022] ii. a sulfated solid support comprising Sulfate ion (SO.sub.4.sup.2) in an amount ranging between 5 to 17 wt-%, wherein said support comprises hydroxides of zirconium, aluminum, ytterbium and copper. In the above definition MOx denotes the mixed metal oxide [0023] iii. at least one lanthanide series element wherein the Lanthanide element:Zr concentration ranges between 0.01 to 2.35 mole %; and [0024] iv. The final catalyst support (excluding the sulfate ion) bearing molecular formula

x.sub.1ZrO.sub.2.x.sub.2Al.sub.2O.sub.3.x.sub.3Yb.sub.2O.sub.3.x.sub.4CuO [0025] wherein the molar coefficients for individual metal oxides are as follows: [0026] x1=55 to 7510.sup.2; x2=12 to 2510.sup.2; x3=1 to 610.sup.2 and x4=0.1 to 510.sup.2; [0027] v. Platinum group metal including but not limited to Platinum, Pallladium, Iridium, Rhenium, Rhodium and Ruthenium is then spray impregnated on the sulfated support in a weight percentage of 0.05 to 2 wt %. [0028] vi. The catalyst thus prepared is then calcined at a temperature 300 to 800 C. and formed into the desired shape as desired by the specific hydrocarbon conversion process (alkylation or isomerization).

[0029] The sulfated mixed metal oxide based catalyst composition in accordance with the present disclosure comprises a solid support comprising oxides of zirconium, aluminum, ytterbium and copper. The solid support comprising oxides of the aforementioned metals (i.e. zirconium, aluminum, ytterbium and copper) is sulfated with sulfur and further loaded with platinum group metals.

[0030] As described above, the metal loaded in the sulfated zirconium oxide based catalyst composition of the present disclosure is present in an amount varying between 0.05 to 2.0 wt %, based on the total molar mass of the final catalyst. The amount of each of above described metals loaded in the catalyst composition of the present disclosure is not same and can be varied according to the type of the metal loaded.

[0031] In accordance with another exemplary embodiment of the present disclosure, the sulfated zirconium oxide based catalyst composition further comprises at least one noble metal selected from the group consisting of Ru, Re, Rh, Ir, Pd and Pt.

[0032] In another aspect, the present disclosure provides a process for the preparation of a sulfated mixed metal oxide based catalyst composition.

[0033] The process for the preparation of the sulfated mixed metal oxide based solid catalyst composition in accordance with the present disclosure comprises the steps of reacting a zirconium and an aluminum precursor in the presence of a lanthanide series element, specifically ytterbium, copper and a sulfate species to obtain a solid support comprising hydroxides of zirconium and aluminum, depositing sulfur and a metal on the solid support to obtain sulfated zirconium oxide based catalyst composition of the present disclosure.

[0034] In accordance with one of the exemplary embodiments of the present disclosure, the process for the preparation of a sulfated zirconium oxide based catalyst composition comprising the following steps: [0035] i. reacting at least one of aluminum precursor and zirconium precursor in the presence of at least one ytterbium and copper, and at least one sulfate species to obtain a solution; [0036] ii. introducing a base solution to the salt solution at a pre-determined temperature to precipitate a product comprising hydroxides of either zirconium or aluminum or both; [0037] iii. Drying the precipitate after removal of unwanted ions by washing. [0038] iv. Additionally adjusting the sulfate content in the catalyst using sulfating agents to obtain a sulfated product having sulfur content in the range of 5 to 17 wt %, based on the total mass of the final product; and [0039] v. calcining the metal loaded sulfated product to obtain a sulfated zirconium oxide based catalyst composition at a temperature of 300 to 800 C. [0040] vi. Optionally depositing noble metals from the group of Ru, Rh, Pt, Pd and Ir on the catalyst depending on the final application of the product. [0041] vii. The final catalyst can also be formed into suitable physical forms such as pellets or extrudes to increase the hydrocarbon reaction efficacy under test.

[0042] The aluminum precursor suitable for the purpose of the present disclosure includes, but is not limited to, chlorides, nitrates, pseudo bohemite and/or sulfates of aluminum. Similarly, the suitable examples of zirconium precursor in accordance with present disclosure include, but are not limited to, chlorides, oxychlorides, nitrates and sulfates of zirconium.

[0043] In accordance with one of the exemplary embodiments of the present disclosure, the molar proportion of aluminum to zirconium metal precursor (Al:Zr) varies between 0.00 and 5%; molar proportion of the lanthanide series element varies between 0.001 and 3%; molar proportion of the copper varies between 0.001 to 3% molar and the molar proportion of sulfate species to zirconium metal precursor varies between 0.03 and 4.3%.

[0044] The sulfate species used for the purpose of the present disclosure is the conventionally used sulfate species. However, the suitable examples of such sulfate species for the purpose of the present disclosure include, but are not limited to H.sub.2S, mercaptans or SO.sub.2 which can provide sulfate ions, H.sub.2SO.sub.4 (NH4).sub.2SO.sub.4 and Na.sub.2S.sub.2O.sub.8.

[0045] The method step of depositing the metal on the sulfated product in accordance with the process of the present disclosure is carried out by treating the sulfated product with at least one metal precursor. The metal precursor suitable for the purpose of the present disclosure includes, but is not limited to, nitrates, sulfates, chlorides and acetates. The metal may be deposited on the sulfated product by employing methods known in the prior-art.

[0046] The metal loaded sulfated product in accordance with the present disclosure is calcined at a temperature varying between 300 and 800 C. for a pre-determined period of time to obtain a final sulfated zirconium oxide based catalyst composition. The calcination of the sulfated product is performed in different stages.

[0047] In accordance with one of the embodiments of the present disclosure, the metal loaded sulfated product is calcined at two different stages. The first stage calcination is carried out at a temperature varying between 300 and 550 C. and at a rate varying between 1 and 5 C./min whereas the second stage calcination is carried out at a temperature varying between 550 and 800 C. and at rate varying between 1 and 10 C./min.

[0048] The calcination at different stages provides a uniform crystal structure. The sulfated mixed metal oxide based catalyst composition in accordance with the present disclosure comprises teteragonal structure which is required for high catalytic activity. The surface area of the sulfated zirconium oxide based catalyst composition in accordance with the one of the exemplary embodiments of the present disclosure varies between 100 and 150 m.sup.2/g.

[0049] The process for the preparation of the sulfated metal oxide based catalyst composition in accordance with the present disclosure further comprises a method step of impregnating at least noble metal on the sulfated zirconium oxide based catalyst composition. The noble metal in accordance with the present disclosure includes, but is not limited to Ru, Rh, Pd, Pt and Ir. The noble metal may be impregnated by using methods commonly known in the prior-art. The impregnation of the noble metal is carried out in such a way so that the final particle size of the sulfated zirconium oxide based catalyst is less than 4 nm, as measured by TEM.

[0050] The sulfated mixed metal oxide based catalyst composition of the present disclosure is used in various hydrocarbon conversion processes, specifically for alkylation and isomerization.

[0051] In still another aspect, the present disclosure provides hydrocarbon conversion processes that include, but are not limited to, isomerization, dimerization, alkylation and acylation by using a sulfated zirconium oxide based catalyst composition of the present disclosure.

[0052] In accordance with one of the exemplary embodiments of the present disclosure, the sulfated zirconium oxide based catalyst composition of the present disclosure is used for the alkylation and isomerization reactions, the results of which are provided below in Table-1 and Table-2.

[0053] Table-1: Alkylation of Toluene with Benzyl Chloride:

[0054] The catalyst was calcined at a temperature between 400-600 C. for 4 hours and reduced in H.sub.2 atmosphere for 2 hours at a temperature between 150-350 C. before following reaction was conducted. Reactants are charged in the reaction chamber fitted with a condenser in the amounts described in table 1. The reactants are brought to reflux and the reaction is conducted for 1.5 hours. The reactants are then cooled the products are analyzed using a Gas Chromatograph with an OV-101 column.

TABLE-US-00001 TABLE 2 Isomerization: Toluene 37.5 gms Benzyl chloride 9.5 gms Catalyst used 0.09 gms Conversion of Benzyl chloride 100% (after 1.5 hour of operation) Selectivity to di-phenyl benzene 99.7%

[0055] The catalyst was calcined at a temperature between 400-600 C. for 4 hours and reduced in H.sub.2 atmosphere for 2 hours at a temperature between 150-350 C. before following reaction was conducted. The catalyst synthesized as described previously was loaded in a fixed bed reactor at the desired temperature and pressure. The reactant feed was vaporized before contacting with the catalyst and the products were cooled using a gas liquid separator. The products and reactants were analyzed using a gas chromatograph with OV-101 column.

TABLE-US-00002 Concentration and operating conditions n-pentane 35% n-hexane 53% Cyclohexane 10% n-heptane 2% H.sub.2/HC 1-4 Pressure 20-38 MPa Temperature 150-180 C. 2,2,-dimethylbutane 35.4% (2,2-DMB)/C6 (1 hr) 2,2-DMB/C6 (500 hrs) 35.5% WHSV 2 h.sup.1

[0056] It is evident from the data of Table-1 and Table-2 that the sulfated zirconium oxide based catalyst composition of the present disclosure shows high activity and retains the same over wide and extended operating conditions.

[0057] Throughout this specification the word comprise, or variations such as comprises or comprising, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

[0058] The use of the expression at least or at least one suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results.

[0059] Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the invention as it existed anywhere before the priority date of this application.

[0060] The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.

[0061] The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

[0062] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

TECHNICAL ADVANCEMENT

[0063] The present disclosure relates to a sulfated mixed metal oxide based catalyst composition and a process for the preparation thereof, has several technical advancements that include, but are not limited to, the realization of high catalytic activity and high stability over wide and extended operating conditions for hydrocarbon conversion processes, specifically alkylation and isomerization.