Surface stabilized active alumina

Claim 2

A PSEUDOBOEHMITIC ALUMINA OF HIGH THERMAL STABILITY, HAVING SELECTIVE ISOMERIZATION PROPERTIES, CHARACTERIZED BY A UNIFORMLY DISTRIBUTED PO4-CONTENT FROM ABOUT 1% TO ABOUT 20% BY WEIGHT CALCULATED ON THE WEIGHT OF THE ALUMINA WHEN HEATED TO 1000*C FOR 1 HOUR, A PSEUDOBOEHMITE CONTENT OF AT LEAST ABOUT 30% BY WEIGHT AS DETERMINED BY X-RAY DIFFRACTION USING COPPER KA RADIATION, WHEREIN THE DIFFRACTION PEAK OF GREATEST INTENSITY (I/O) IS IN THE RANGE OF 6.5-6.8 A, A SURFACE AREA OF AT LEAST ABOUT 300 M2/G AFTER HEATING THE COMPOSITE TO 600*C FOR 2 HOURS.

Claim 3

A pseudoboehmitic alumina of high thermal stability, having selective isomerization properties, characterized by a uniformly distributed PO4-content from about 1% to about 20% by weight calculated on the weight of the alumina when heated to 1000*C for 1 hour, a pseudoboehmite content of at least about 30% by weight as determined by X-ray diffraction using copper K Alpha radiation, wherein the diffraction peak of greatest intensity (I/Io) is in the range of 6.5-6.8 A, a surface area of at least about 300 m2/g after heating the composite to 600*C for 2 hours.

Claim 4

A pseudoboehmitic alumina of high thermal stability, having selective isomerization properties, characterized by a uniformly distributed PO4-content from about 1% to about 20% by weight calculated on the weight of the alumina when heated to 1000*C for 1 hour, a pseudoboehmite content of at least about 30% by weight as determined by X-ray diffraction using copper K Alpha radiation, wherein the diffraction peak of greatest intensity (I/Io) is in the range of 6.5-6.8 A, a surface area of at least about 300 m2/g after heating the composite to 600*C for 2 hours.

Claim 5

The surface stabilized pseudoboehmitic alumina of claim 1, characterized by a PO4-content from about 2% to about 18% by weight.

Claim 6

A process for producing a surface stabilized pseudoboehmitic alumina which comprises: a. forming an aqueous reaction mixture from a basic aluminum source selected from the group consisting essentially of sodium aluminate and potassium aluminate and an acid and incorporating in the mixture a phosphate ion yielding compound of the general formula AxHyPO4 wherein A is selected from the group consisting essentially of Na, K, Li and NH4; and wherein x and y are whole numbers from 0 to 3 and the sum of x + y is equal to 3, and wherein for NH4 x is 1 and 2, in an amount sufficient to produce a pseudoboehmitic alumina containing from about 1% to about 20% by weight PO4-content calculated on the weight of the composite when heated to 1000*C for 1 hour, b. recovering the PO4-containing pseudoboehmitic alumina followed by drying within a temperature range from about 110*C to about 140*C, and c. thermally treating the dried pseudoboehmitic alumina within a temperature range from about 300*C to about 600*C, from 30 minutes to about 3 hours.

Claim 7

A process for producing a surface stabilized pseudoboehmitic alumina which comprises: a. forming an aqueous reaction mixture from a basic aluminum source selected from the group consisting essentially of sodium aluminate and potassium aluminate and an acid and incorporating in the mixture a phosphate ion yielding compound of the general formula AxHyPO4 wherein A is selected from the group consisting essentially of Na, K, Li and NH4; and wherein x and y are whole numbers from 0 to 3 and the sum of x + y is equal to 3, and wherein for NH4 x is 1 and 2, in an amount sufficient to produce a pseudoboehmitic alumina containing from about 1% to about 20% by weight PO4-content calculated on the weight of the composite when heated to 1000*C for 1 hour, b. recovering the PO4-containing pseudoboehmitic alumina followed by drying within a temperature range from about 110*C to about 140*C, and c. thermally treating the dried pseudoboehmitic alumina within a temperature range from about 300*C to about 600*C, from 30 minutes to about 3 hours.

Claim 8

Process according to claim 3, wherein the AxHyPO4 compound is added in an amount sufficient to produce a stabilized pseudoboehmitic alumina containing from about 2% to about 18% by weight of PO4.

Claim 9

Process according to claim 3, wherein the basic aluminum source is sodium aluminate, the AxHyPO4 compound is selected from the group consisting essentially of Na3PO4, Na2HPO4 and NaH2PO4 and wherein the AxHyPO4 compound is incorporated in the sodium aluminate prior to forming the reaction mixture.

Claim 10

Process according to claim 3, wherein the acid is nitric acid and the AxHyPO4 compound is H3PO4 and wherein the H3PO4 is incorporated in the nitric acid prior to forming the reaction mixture.

Claim 11

A process for producing a surface stabilized pseudoboehmitic alumina exhibiting increased thermal stability and possesing selective isomerization characteristics from pseudoboehmite characterized by a pseudoboehmite content of at least about 30% by weight as determined by X-ray diffraction using copper K Alpha radiation, wherein the diffraction peak of greatest intensity (I/Io) is in the range of 6.5-6.8 A which comprises: a. adding to pseudoboehmitic alumina a phosphate ion yielding compound having the general formula of AxHyPO4, wherein A is selected from the group consisting essentially of Na, K, Li and NH4; and wherein the sum of x + y is 3 and y is 0, 1, or 2, where A is NH4, x is 1 or 2, in an amount sufficient to produce a phosphate stabilized pseudomitic alumina having a pseudoboehmite content of at least about 30% by weight and a PO4-content from about 1% to about 20% by weight calculated on the weight of the composite when heated to 1000*C for 1 hour; b. uniformly distributing the AxHyPO4 in the pseudoboehmitic alumina followed by drying within a temperature range from about 110*C to about 140*C; and c. thermally treating the dried alumina within a temperature range from about 300*C to about 600*C from about 30 minutes to about 3 hours.

Claim 12

A process for producing a surface stabilized pseudoboehmitic alumina exhibiting increased thermal stability and possesing selective isomerization characteristics from pseudoboehmite characterized by a pseudoboehmite content of at least about 30% by weight as determined by X-ray diffraction using copper K Alpha radiation, wherein the diffraction peak of greatest intensity (I/Io) is in the range of 6.5-6.8 A which comprises: a. adding to pseudoboehmitic alumina a phosphate ion yielding compound having the general formula of AxHyPO4, wherein A is selected from the group consisting essentially of Na, K, Li and NH4; and wherein the sum of x + y is 3 and y is 0, 1, or 2, where A is NH4, x is 1 or 2, in an amount sufficient to produce a phosphate stabilized pseudomitic alumina having a pseudoboehmite content of at least about 30% by weight and a PO4-content from about 1% to about 20% by weight calculated on the weight of the composite when heated to 1000*C for 1 hour; b. uniformly distributing the AxHyPO4 in the pseudoboehmitic alumina followed by drying within a temperature range from about 110*C to about 140*C; and c. thermally treating the dried alumina within a temperature range from about 300*C to about 600*C from about 30 minutes to about 3 hours.

Claim 13

Process according to claim 7, wherein the pseudoboehmitic alumina is in an aqueous slurry.

Claim 14

Process according to claim 7, wherein the pseudoboehmitic alumina is a filter cake.

Claim 15

Process according to claim 7, wherein the pseudoboehmitic alumina is an alumina dried within a temperature range from about 110*C to about 140*C prior to addition of the AxHyPO4 compound.