Mesoporous aluminas stabilized with rare earth and phosphorous
AssigneeExxonMobil Research and Engineering Company
InventorsKun Wang, Robert C. Lemon
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Abstract
A mesoporous oxide composition includes, other than oxygen, a major amount of aluminum and lesser amounts of phosphorus and at least one rare earth element. The compositions have high surface area and excellent thermal and hydrothermal stability, with a relatively narrow pore size distribution in the mesoporous range. These compositions may be prepared by a hydrothermal co-precipitation method using an organic templating agent. These mesoporous oxide compositions may be used as catalysts or as supports for catalysts, for example, in a fluid catalytic cracking process.
Claims13
A method for making a mesoporous alumina composition comprising, in addition to aluminum (Al), at least one rare earth element (RE) and phosphorus (P), said method comprising the steps of:
- (a) forming a reaction mixture comprising a source of at least one rare earth element, a source of aluminum, a source of phosphorus, and a mesopore templating agent in a liquid medium;
- (b) maintaining said reaction mixture of step (a) under conditions sufficient to precipitate said sources of rare earth element, aluminum, phosphorus and said mesopore templating agent to form an as-synthesized form of said mesoporous alumina composition comprising residual mesopore templating agent within pores of said mesoporous oxide composition;
- (c) separating said liquid from the as-synthesized form of said mesoporous alumina composition obtained in step (b);
- (d) optionally, removing at least a portion said mesopore templating agent from said as-synthesized form of said mesoporous alumina composition of step (c) by solvent extraction;
- and
- (e) calcining said as-synthesized form of said mesoporous alumina composition of step (c) or step (d) under calcination conditions to form a calcined form of said mesoporous alumina composition, wherein said calcination conditions are sufficient to remove any residual mesopore templating agent and to cause condensation reactions with hydroxyl groups to liberate H2O;
- wherein a molar ratio of Al:P:RE in said reaction mixture of step (a) is 5-10:1:0.5-1, and wherein said calcined form of said mesoporous alumina composition of step (e) has an average pore size of from 45 Angstroms to 80 Angstroms, and a surface area of 150 to 300 m2/g.
A method for making a mesoporous alumina composition comprising, in addition to aluminum (Al), at least one rare earth element (RE), phosphorus (P), and M, where M is at least one element other than oxygen (O), Al, P, and RE capable of being incorporated into said mesoporous alumina composition, said method comprising the steps of:
- (a) forming a reaction mixture comprising a source of at least one rare earth element, a source of aluminum, a source of phosphorus, a source of M, and a mesopore templating agent in a liquid medium;
- (b) maintaining said reaction mixture of step (a) under conditions sufficient to precipitate said sources of rare earth element, aluminum, phosphorus, M, and said mesopore templating agent to form an as-synthesized form of said mesoporous alumina composition comprising residual mesopore templating agent within pores of said mesoporous alumina composition;
- (c) separating said liquid from the as-synthesized form of said mesoporous alumina composition obtained in step (b);
- (d) optionally, removing at least a portion said mesopore templating agent from said as-synthesized form of said mesoporous alumina composition of step (c) by solvent extraction;
- and
- (e) calcining said as-synthesized form of said mesoporous alumina composition of step (c) or step (d) under calcination conditions to form a calcined form of said mesoporous alumina composition, wherein said calcination conditions are sufficient to remove any residual mesopore templating agent and to cause condensation reactions with hydroxyl groups to liberate H2O;
- wherein a molar ratio of Al:P:RE:M in said reaction mixture of step (a) is 5-10:1:0.5-1:up to 0.3, and wherein said calcined form of said mesoporous alumina composition of step (e) has an average pore size of from 45 Angstroms to 200 Angstroms and a mono-modal pore size distribution.
Dependencies are inferred from the claim text.