PROCESS FOR PRODUCING AN OLIGOMERIZATION CATALYST

Abstract

The invention relates to a process for producing an oligomerization catalyst comprising nickel oxide and a silicon-alumina support material, wherein the silica-alumina support material is in the ammonium form. The present invention further relates to a process for oligomerization of C3- to C6-olefins using the oligomerization catalyst produced according to the invention.

Claims

1. A process for producing an oligomerization catalyst, comprising at least the steps of: a) mixing an amorphous silica-alumina support material comprising from 10% to 20% by weight of Al.sub.2O.sub.3 and from 80% to 90% by weight of SiO.sub.2, an Al-containing and Si-free or Al-free and Si-containing binder, and at least a portion of a nickel source is an aqueous, ammonia-free nickel solution of a nickel compound, an aqueous, ammonia-free nickel paste of a nickel compound or a combination of the abovementioned nickel solution and the abovementioned nickel paste, wherein the nickel compound is selected from the group consisting of nickel nitrate (Ni(NO.sub.3).sub.2), nickel acetate (Ni(ac).sub.2), nickel acetylacetonate (Ni(acac).sub.2), nickel sulfate (NiSO.sub.4), nickel citrate or nickel carbonate (NiCO.sub.3), and granulating the resulting mixture; b) treating the granulate produced in step a) with at least a portion of a nickel source as defined for step a) provided that the entirety of the nickel source has not already been mixed with the amorphous silica-alumina support material and the binder in step a); and c) calcining the granulate to produce the oligomerization catalyst; wherein the amorphous silica-alumina support material in step a) is in the ammonia form.

2. The process according to claim 1, wherein step a) comprises employing an oxidic aluminium material as the Al-containing and Si-free binder or silicon dioxide as the Al-free and Si-containing binder.

3. The process according to claim 2, wherein the Al-containing and Si-free binder is selected from the group consisting of aluminium oxide, aluminium hydroxide and aluminium oxide hydroxide.

4. The process according to claim 1, wherein the aqueous, ammonia-free nickel paste comprises between 30% and 50% by weight of nickel based on the total weight of the nickel paste.

5. The process according to claim 4, wherein a paste composed of nickel carbonate and water as solvent, wherein the nickel is present as carbonate/hydroxide, is used as the aqueous, ammonia-free nickel paste.

6. The process according to claim 1, wherein the aqueous, ammonia-free nickel solution comprises nickel in an amount in the range of from 1% to 20% by weight based on the total weight of the solution.

7. The process according to claim 6, wherein an aqueous, ammonia-free Ni(CO.sub.3) or Ni(NO.sub.3).sub.2 solution is used as the aqueous, ammonia-free nickel solution.

8. The process according to claim 1, wherein the calcination in step c) is performed at a temperature between 400 C. and 800 C.

9. The process according to claim 6, wherein the calcination in step c) is performed in a nitrogen stream.

10. The process according to claim 1, wherein the oligomerization catalyst has a final composition of from 15% to 40% by weight of NiO, from 10% to 30% by weight of Al.sub.2O.sub.3, from 55% to 70% by weight of SiO.sub.2 and optionally from 0.01% to 2.5% by weight of an alkali metal oxide.

11. The process for oligomerization of C3- to C6-olefins, wherein olefin-containing input mixture containing the C3- to C6-olefins is passed over a catalyst in a reaction zone, wherein an oligomerization catalyst produced by the process according to claim 1 is used for catalysis of the oligomerization reaction.

12. The process for oligomerization according to claim 11, wherein the olefin-containing input mixture contains less than 2% by weight of branched olefins.

13. The process for oligomerization according to claim 11, wherein the oligomerization takes place in the liquid phase.

14. The process for oligomerization according to claim 11, wherein the oligomerization is carried out at a pressure of 10 to 70 bar and a temperature of from 50 C. to 200 C., wherein if the oligomerization is carried out in the liquid phase, the parameters pressure and temperature are chosen such that the reactant stream is in the liquid phase.

15. The process according to claim 1, wherein the oligomerization catalyst has a final composition of from 15% to 30% by weight of NiO and from 0.01% to 2.5% by weight of an alkali metal oxide.

16. The process according to claim 3, wherein the aqueous, ammonia-free nickel paste comprises between 30% and 50% by weight of nickel based on the total weight of the nickel paste.

17. The process according to claim 3, wherein the aqueous, ammonia-free nickel solution comprises nickel in an amount in the range of from 1% to 20% by weight based on the total weight of the solution.

18. The process according to claim 3, wherein the calcination in step c) is performed at a temperature between 400 C. and 800 C.

19. The process according to claim 3, wherein the oligomerization catalyst has a final composition of from 15% to 30% by weight of NiO, from 10% to 30% by weight of Al.sub.2O.sub.3, from 55% to 70% by weight of SiO.sub.2 and optionally from 0.01% to 2.5% by weight of an alkali metal oxide.

20. The process for oligomerization of C3- to C6-olefins, wherein olefin-containing input mixture containing the C3- to C6-olefins is passed over a catalyst in a reaction zone, wherein an oligomerization catalyst produced by the process according to claim 3 is used for catalysis of the oligomerization reaction.

Description

EXAMPLES

[0050] A commercially available amorphous aluminosilicate was initially (virtually) completely converted into the ammonium form by admixing with an excess of ammonium-containing solution and subsequent drying at 100 C. to 120 C., i.e. it was ensured that all acid centres were masked by ammonium ions.

Catalyst 1 (Inventive):

[0051] A binder (colloidal solution comprising silicon dioxide, SiO.sub.2 content between about 30% by weight) and the amorphous aluminosilicate were placed in the mixing vessel of an intensive mixer and stirred. Stirring was stopped as soon as granulates having a suitable particle diameter (0.1 mm to 7 mm) are obtained. The thus obtained granulate was dried at about 120 C. and subsequently screened using two screens to remove excessively small or excessively large particles from the granulate.

[0052] The dry granulate was subsequently impregnated with an aqueous Ni(NO.sub.3).sub.2 solution (Ni content between 10% and 12.5% by weight). The granulate is then calcined in a furnace. For the calcination the granulate is heated to a temperature between 500 C. to 600 C. and this temperature is maintained for about 10 to 12 hours. The furnace filled with granulate has nitrogen flowing through it and a ratio of volumes of granulate to volumes of nitrogen per hour (standard volumes) of at least 1:1000 is maintained. During the cooling of the granulate to room temperature about 6000 ppm by volume of air were metered into the nitrogen stream. The cooled granulate corresponds to the finished oligomerization catalyst.

Catalyst 2 (Noninventive):

[0053] To produce catalyst 2 the initially produced aluminosilicate in ammonium form was calcined at 400 C. This drove out a portion of the ammonium cations which masked the acid centres. The aluminosilicate used for producing the catalyst is thus partially in the H form.

[0054] The production of catalyst 2 was then performed as per claim 1 with the exception that the aluminosilicate isas mentionedpartially in the H form.

Catalyst 3 (Noninventive):

[0055] To produce catalyst 3 the initially produced aluminosilicate in ammonium form was calcined at 550 C. This drove out the entirety of the ammonium cations which masked the acid centres. The aluminosilicate used for producing the catalyst is thus virtually completely in the H form.

[0056] The production of catalyst 2 was then performed as per claim 1 with the exception that the aluminosilicate isas mentionedcompletely in the H form.

Use of the Catalysts in the Oligomerization:

[0057] About 12 g of the catalyst in each case were introduced into a metal tube having an internal diameter of 6 mm. Added in front of and behind the catalyst were glass beads having a diameter of 2 mm, which serve as a pre-heating and cooling phase. The oligomerization was performed using a butene/butane mixture comprising 80% n-butenes at 30 bar and a loading of 7.5 g/h of butene per gram of catalyst, wherein the reaction temperature was varied between 80 C. and 100 C. The products were analysed by gas chromatography for the conversion of butenes and the linearity of the octenes.

[0058] The conversions and selectivities achieved as a function of temperature for catalyst 1 (inventive) and the noninventive catalysts 2 and 3 and also the ISO indices resulting therefrom are reported in tables 1 to 3.

TABLE-US-00001 TABLE 1 Conversions and ISO indices in oligomerization using catalyst 1 Loading (feed of C4-olefins in g/h per unit mass of catalyst in g) as WHSV: 7.5 h.sup..sup.1 Conversion ISO Temperature based on C4-olefins index Catalyst 1 80 C. 37.4% 1.18 (inventive) 90 C. 40.3% 1.18 100 C. 45.6% 1.16

TABLE-US-00002 TABLE 2 Conversions and ISO indices in oligomerization using catalyst 2 Loading (feed of C4-olefins in g/h per unit mass of catalyst in g) as WHSV: 7.5 h.sup.1 Conversion ISO Temperature based on C4-olefins index Catalyst 2 80 C. 27.1% 1.20 (noninventive) 90 C. 29.9% 1.21 100 C. 33.9% 1.23

TABLE-US-00003 TABLE 3 Conversions and ISO indices in oligomerization using catalyst 3 Loading (feed of C4-olefins in g/h per unit mass of catalyst in g) as WHSV: 7.5 h.sup.1 Conversion ISO Temperature based on C4-olefins index Catalyst 3 80 C. 20.7% 1.30 (noninventive) 90 C. 19.4% 1.33 100 C. 30.0% 1.37

[0059] It is apparent that, surprisingly, the use of the amorphous aluminosilicate in the ammonium form in the production of the catalyst resulted in markedly improved conversions and lower iso-indices for the product mixture.