Catalyst and process for the isomerization of olefins in the presence of reactive impurities

An activated isomerization catalyst prepared by:

• providing a substantially dry support material consisting essentially of an alumina prepared from a starting material consisting essentially of a pseudoboehmite wherein said alumina has a surface area selected from the group consisting of in the range of from about 125 m.sup.2 /g to about 195 m.sup.2 /g when prepared from a starting material consisting of a first pseudoboehmite having an average crystallite size substantially the same as a catapal grade pseudoboehmite or wherein said alumina has a surface area in the range of from about 230 m.sup.2 /g to about 260 m.sup.2 /g when prepared from a starting material of a second pseudoboehmite having an average a crystallite size smaller than a catapal grade pseudoboehmite;
• mixing a metallic form of an alkali metal and the substantially dry support material under conditions comprising a time and an elevated temperature effective to ensure substantially complete thermal mixing and to produce a catalyst precursor mixture comprising a substantially uniform dispersion of the alkali metal on the support;
• activating the catalyst precursor mixture by treatment with an oxygen-containing gas under conditions effective to produce an activated catalyst which maintains a higher rate of activity during isomerization than said catalyst maintains in the absence of said treatment with said oxygen-containing gas.

An activated isomerization catalyst prepared by:

• providing a substantially dry support material consisting essentially of an alumina prepared from a starting material consisting essentially of a pseudoboehmite wherein said alumina has a surface area selected from the group consisting of in the range of from about 125 m.sup.2 /g to about 195 m.sup.2 /g when prepared from a starting material consisting of a first pseudoboehmite having an average crystallite size substantially the same as a catapal grade pseudoboehmite or wherein said alumina has a surface area in the range of from about 220 m.sup.2 /g to about 280 m.sup.2 /g when prepared from a starting material of a second pseudoboehmite having an average a crystallite size smaller than a catapal grade pseudoboehmite;
• mixing a metallic form of an alkali metal comprising sodium and the substantially dry support material under conditions comprising a time and an elevated temperature effective to ensure substantially complete thermal mixing and to produce a catalyst precursor mixture comprising a substantially uniform dispersion of the alkali metal on the support;
• activating the catalyst precursor mixture by treatment with an oxygen-containing gas under conditions effective to produce an activated catalyst which maintains a higher rate of activity during isomerization than said catalyst maintains in the absence of said treatment with said oxygen-containing gas.