WO2009131474A2

WO2009131474A2 - Gasoline synthesis catalyst

Info

Publication number: WO2009131474A2
Application number: PCT/PL2009/000037
Authority: WO
Inventors: Dobieslaw Nazimek; Stanislaw Jablonski; Waldemar Zaniuk
Original assignee: Uniwersytet Marii Curie Sklodowskiej
Priority date: 2008-04-22
Filing date: 2009-04-21
Publication date: 2009-10-29
Also published as: PL207580B1; AU2009238764A1; PL384999A1; EP2276565A2; WO2009131474A3

Abstract

The subject of the present invention is a catalyst for the synthesis of gasolines from methanol or its homologues, in particular its nanostructural matrix having high catalytic resistance to water, even as high as above 100 ppm and making it possible to appropriately deposit active sites onto it, which results in high and long-lasting activity of the catalyst and its selectivity towards increasing the degree of hydrocarbons isomerisation to increase the octane number of the gasoline to be obtained. Preferably the catalyst is in form of copper ions supported on an aluminosilicate matrix.

Description

Gasoline synthesis catalyst.

The subject of the present invention is a nanostructural catalyst for the synthesis of gasolines, in particular via a low alcohol route, where water is a by-product, e.g.

catalyst nCH₃O C_nH_n+x + H₂O

The values n and x in the above equation are dependent on the temperature and pressure in the system as well as the catalyst used in the process. This means that the catalyst, which, beside enabling the very synthesis reaction to occur, also influences the degree of the coupling process related to the degree of isomerisation of hydrocarbons to increase the octane number of the gasoline to be obtained. Also important is the catalyst's resistance to water present as a by-product of the synthesis.

So far, syntheses of gasoline from methanol or its homologues have been carried out using known catalysts e.g. copper catalyst, supported on an aluniinosilicate matrix in the form of a zeolite, characterised by high molecular Al₂O₃ZSiO₂ ratio, at about 40, denominated by the symbol ZSM-5. Polish patent specification PL 244883. The relatively high content of Al₂O₃ in the matrix results in zeolite catalysts' high vulnerability to water present in the reaction environment, which directly affects their activity.

The objective of the present invention is to provide a novel catalyst formula for the synthesis of gasolines from methanol or its homologues, in particular its matrix, having high catalytic resistance to water, even above 100 ppm, that would also allow active sites to be appropriately deposited thereon for high and long-lasting activity of the catalyst and its selectivity towards increasing the degree of isomerisation of hydrocarbons in order to increase octane number of the gasoline to be obtained.

The catalyst according to the present invention characterises in that its active sites in the form of copper ions are introduced in a coordinated octahedral structure and at a preferable amount of Cu in a range of 0,2 to 0,5 % by weight of the metal, by known methods, onto nanostructural aluminosilicate matrixes, in particular 10-channel matrixes of monoclinic crystal structure with channel dimensions from 7,6 A to 3,0 A, of high adsorptive capacity and ion exchange selectivity, thermal stability in the range 973 - 1023 K, and, preferably, Al₂O₃ to SiO₂ molar ratio of max 10, and total surface area not greater than 40 m2/g, in particular in the form of ferrierite or clinoptilolite granules.

The present invention is illustrated by the following embodiments. Example 1.

A catalyst named FERR-Cu was prepared, where as the matrix there were used 1,5 to 3 mm diameter granules of ferrierite, a hydrated aluminosilicate of sodium, potassium and magnesium in sodium form, of general formula (Na₅K)₂Mg[OHZAl₃Si₁₅O₃₆] ^• 9H₂O, crystallised in a rhomboidal system in the form of needle-shaped crystals characterised by the following physicochemical data:

- Al₂O₃ZSiO₂ molecular ratio - approx. 10

- approximate channel dimensions: width - 7,6 A and height 3 A

- total surface area determined by BET method (argon absorption at liquid nitrogen temperature) - S_og- approx. 35 m²Zg,

- thermal stability - 973 K

Onto the matrix thus prepared, Cu active sites were deposited by ion exchange from an ammoniacal solution, at an amount of 0,2 % by weight, and then, after recovery from the solution, drying and calcination, the final catalyst was obtained.

Example 2.

A catalyst named KLIP-Cu was prepared, where as the matrix there was used clinoptylolite, a natural zeolite of identical chemical composition to that of ferrierite, crystallised in a monoclinical system (Cm symmetry group), in the form of granules of 1,5 to 3 mm in diameter, characterised by the following physicochemical data:

- Al₂O₃ZSiO₂ molar ratio - approx. 4

- approximate channel dimensions: width- 7,6 A and height 3 A - total surface area determined by BET method (argon absorption at liquid nitrogen temperature) - S_og - approx. 40 m²/g,

- thermal stability - 1023 K

Onto the matrix thus prepared, Cu ions were deposited by impregnation at an amount of 0,5 % from its nitrate solution, using EDTA as the complexing agent. After recovery from the solution, drying and calcination, the final catalyst was obtained.

The catalysts according to the present invention were subjected to evaluation in kinetic tests in ethanol coupling processes, assuming that an indicator of catalyst activity will be the reaction rate expressed as TOF (Turnover Frequency) towards the formation of ETBE (ethyl tert-butyl ether) as the most desirable product, as well as towards the formation of isomeres above C₅ hydrocarbons.

The test results indicate that for both the FEER-Cu and the KLIP-Cu catalyst the apparent reaction activation energy, ΔE, is approx. 300 kJ/mol, selectivity towards ETBE - approx. 45%, and towards isomeres above C₅ - approx. 30% while the selectivity towards undesirable products - CO₂ and CO not greater than 10 - 12%. A comparison of the above data with those of known zeolite catalysts allows one to state that the catalyst according to the present invention is highly active, selective and relatively resistant to the presence of water, which makes it possible to favorably use it in ethanol coupling processes to obtain higher, more technologically desired hydrocarbons even with 5% by volume of water in it.

Claims

1. A gasoline synthesis catalyst with active sites in the form of copper ions supported on an aluminosilicate matrix, characterised in that copper ions are introduced in a coordinated octahedral structure at an amount between 0,2 to 0,5 % by weight of metal, onto a nanostructural aluminosilicate matrix of monoclinic crystallographic structure, high adsorptive capacity and ion exchange selectivity, as well as at Al₂O₃ to SiO₂ molar ratio of max. 10 and thermal stability in the range 973 - 1023 K.

2. The catalyst according to claim 1, characterised in that its nanostructural matrix has a 10-channel structure with channel dimensions from 7,6 A to 3,0 A.

3. The catalyst according to claim 1, characterised in that the total surface area of its nanostructural matrix is not greater than 40 m²/g.

4. The catalyst according to claim 1, characterised in that its nanostructural matrix is in the form of ferrierite granules.

5. The catalyst according to claim 1, characterised in that its nanostructural matrix is in the form of clinoptylolite granules.