Hydrocarbon conversion process with catalytically active amorphous silica
AssigneeUnion Oil Company of California
InventorsDean A. Young, Jeffery W. Koepke
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Abstract
Catalytically active amorphous silicas are prepared by dehydrating a silica hydrogel or precipitate prepared from an acidified aqueous silicate solution containing an amine of pK.sub.a above 10 or a cation containing either a nitrogen or phosphorus atom bonded to four carbon atoms. The resultant amorphous silica is catalytically active for, among other chemical reactions, the isomerization of orthoxylene and the cracking of hydrocarbons.
Claims25
An isomerization process comprising contacting a hydrocarbon comprising ortho-xylene under isomerization conditions including an elevated temperature with a catalyst prepared by a method comprising forming a hydrogel or precipitate in a reaction mixture comprising water, silicate anions and an organic reactant selected from the group consisting of amines having a pK.sub.a value above about 10.0, quaternary ammonium cations having a nitrogen atom bonded to four carbon atoms, quaternary phosphonium cations having a phosphorus atom bonded to four carbon atoms, precursors of the foregoing and mixtures thereof, and dehydrating the resultant hydrogel or precipitate to yield a product containing amorphous silica, said isomerization conditions are such that at least a portion of said ortho-xylene is converted to para-xylene or meta-xylene.
An isomerization process comprising contacting a hydrocarbon comprising ortho-xylene under isomerization conditions with a catalyst prepared by a method comprising forming a hydrogel in a reaction mixture comprising water, silicate anions and quaternary ammonium cations having a nitrogen atom bonded to four carbon atoms, and dehydrating the hydrogel to yield a product containing a substantial proportion of amorphous silica gel, said isomerization conditions are such that at least a portion of said ortho-xylene is converted to para-xylene or meta-xylene.
An isomerization process comprising contacting a hydrocarbon comprising ortho-xylene in the presence of hydrogen under isomerization conditions with a catalyst prepared by a method comprising acidifying a reaction mixture comprising sodium silicate, water and a quaternary ammonium cation having a nitrogen atom bonded to four carbon atoms, allowing a hydrogel to form in the reaction mixture, separating the hydrogel from the reaction mixture and removing one or more metals from said hydrogel, and dehydrating said hydrogel to produce a product containing a substantial proportion of amorphous silica gel, said isomerization conditions are such that at least a portion of said ortho-xylene is converted to para-xylene or meta-xylene.
An isomerization process comprising contacting a hydrocarbon comprising ortho-xylene under isomerization conditions with a catalyst prepared by a method comprising (a) forming a hydrogel in a reaction mixture comprising water, silicate anions and a quaternary ammonium cation having a nitrogen atom bonded to four carbon atoms, said quaternary ammonium cation is introduced into said reaction mixture by addition of one or more precursors thereof, said precursors being selected from the group consisting of (1) quaternary ammonium compounds containing a nitrogen atom bonded to four carbon atoms and having at least some solubility in water and (2) amines or ammonia in combination with an emulsifying agent and one or more alkyl compounds containing a halide or sulfate, said alkyl compounds being present in an amount at least sufficient to bond at least one nitrogen atom of the amines or ammonia to four carbon atoms, and (b) dehydrating the hydrogel to yield a product containing a substantial proportion of amorphous silica gel, said isomerization conditions are such that at least a portion of said ortho-xylene is converted to para-xylene or meta-xylene.
An isomerization process comprising contacting a hydrocarbon comprising ortho-xylene under isomerization conditions with an amorphous silica, said amorphous silica having catalytic activity for isomerizing ortho-xylene to para-xylene and meta-xylene at 900.degree. F. and atmospheric pressure at a rate of at least 1.0.times.10.sup.10 molecules of ortho-xylene converted per second per square centimeter of surface area of said amorphous silica.
An isomerization process comprising contacing a hydrocarbon comprising ortho-xylene under isomerization conditions with a composition consisting essentially of an amorphous silica gel, said amorphous silica gel having catalytic activity for isomerizating ortho-xylene to para-xylene plus meta-xylene at 900.degree. F. and atmospheric pressure at a rate of at least 4.0.times.10.sup.10 molecules of ortho-xylene converted per second per square centimeter of surface area of said composition.
Dependencies are inferred from the claim text.