Catalytically active amorphous silica

Claim 7

A method as defined in claim 2 or 3 wherein said dehydrating is accomplished by calcining in air at an elevated temperature.

Claim 8

A method as defined in claim 3 wherein said reaction mixture contains sodium as essentially the only alkali or alkaline earth metal therein, and after said sodium removal, said hydrogel contains sodium to silicon in an atom ratio less than about 0.010.

Claim 9

A method as defined in claim 2 or 5 wherein 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.

Claim 10

A method as defined in claim 1 or 2 wherein the pH of the reaction mixture is between about 8 and 12 and wherein the reaction mixture produces a hydrogel while being maintained below 100° C.

Claim 11

A method as defined in claim 3 or 5 wherein said acidifying produces in the reaction mixture a pH between about 10 and 12, and during the formation of said hydrogel, the reaction mixture is maintained at a temperature below 100° C.

Claim 14

A method as defined in claim 3, 5, or 9 wherein said quaternary ammonium cation is introduced into said reaction mixture in precursor form, said precursor form comprising a combination of an amine containing a nitrogen atom bonded to three carbon atoms plus one or more alkyl halides containing between 2 and 4 carbon atoms.

Claim 15

An amorphous silica gel prepared by the method of claim 8.

Claim 16

An amorphous silica gel prepared by the method of claim 2, 3, or 9.

Claim 17

An amorphous silica prepared by the method of claim 1.

Claim 18

An amorphous silica as defined in claim 13 wherein said reaction mixture has an acidic pH.

Claim 19

An amorphous silica as defined in claim 13 wherein said reaction mixture comprises a quaternary phosphonium ion having four alkyl groups attached to a phosphorous atom, with the alkyl groups being the same or different but containing between 1 and 6 carbon atoms.

Claim 20

An amorphous silica useful in the catalysis of hydrocarbon conversion reactions prepared by a method comprising acidifying a reaction mixture comprising water, sodium silicate, and a quaternary ammonium cation having a nitrogen atom bonded to four carbon atoms, said acidifying resulting in a pH between about 8 and 12, allowing the reaction mixture to stand under conditions sufficient to produce a hydrogel therein from which an essentially amorphous silica gel is produced in the dehydrating step hereinafter defined, separating the hydrogel from the remainder of the reaction mixture, washing the hydrogel so as to reduce the sodium content thereof, and dehydrating the washed hydrogel to yield a silica product consisting essentially of an amorphous silica gel.

Claim 21

An amorphous silica useful in the catalysis of hydrocarbon conversion reactions prepared by a method comprising acidifying a reaction mixture comprising water, sodium silicate, and a quaternary ammonium cation having a nitrogen atom bonded to four carbon atoms, said acidifying resulting in a pH between about 8 and 12, allowing the reaction mixture to stand under conditions sufficient to produce a hydrogel therein from which an essentially amorphous silica gel is produced in the dehydrating step hereinafter defined, separating the hydrogel from the remainder of the reaction mixture, washing the hydrogel so as to reduce the sodium content thereof, and dehydrating the washed hydrogel to yield a silica product consisting essentially of an amorphous silica gel.

Claim 22

An amorphous silica as defined in claim 16 wherein said hydrogel is produced in said reaction mixture at a temperature maintained below 100° C.

Claim 23

An amorphous silica having catalytic activity for isomerizing ortho-xylene to para-xylene and meta-xylene at 900° F. and atmospheric pressure at a rate of at least 1.0×10 10 molecules of ortho-xylene converted per second per square centimeter of surface area of said amorphous silica.

Claim 24

An amorphous silica having catalytic activity for isomerizing ortho-xylene to para-xylene and meta-xylene at 900° F. and atmospheric pressure at a rate of at least 1.0×10 10 molecules of ortho-xylene converted per second per square centimeter of surface area of said amorphous silica.

Claim 25

A composition consisting essentially of amorphous silica gel having catalytic activity for isomerizing ortho-xylene to para-xylene plus meta-xylene at 900° F. and atmospheric pressure at a rate of at least 4.0×10 10 molecules of ortho-xylene converted per second per square centimeter of surface area of said composition.

Claim 26

A composition consisting essentially of amorphous silica gel having catalytic activity for isomerizing ortho-xylene to para-xylene plus meta-xylene at 900° F. and atmospheric pressure at a rate of at least 4.0×10 10 molecules of ortho-xylene converted per second per square centimeter of surface area of said composition.

Claim 27

An amorphous silicon-containing hydrogel produced from a reaction mixture comprising water, silicate anions, and an organic reactant selected from the group consisting of amines having a pK a value above 10.0, quaternary ammonium cations wherein a nitrogen atom is bonded to four alkyl groups containing between 1 and 6 carbon atoms, quaternary phosphonium ions wherein a phosphorus atom is bonded to four alkyl groups containing between 1 and 6 carbon atoms, precursors of the foregoing, and mixtures thereof.

Claim 28

An amorphous silicon-containing hydrogel produced from a reaction mixture comprising water, silicate anions, and an organic reactant selected from the group consisting of amines having a pK a value above 10.0, quaternary ammonium cations wherein a nitrogen atom is bonded to four alkyl groups containing between 1 and 6 carbon atoms, quaternary phosphonium ions wherein a phosphorus atom is bonded to four alkyl groups containing between 1 and 6 carbon atoms, precursors of the foregoing, and mixtures thereof.

Claim 29

An amorphous silicon-containing hydrogel as defined in claim 20 wherein said reaction mixture contains quaternary phosphonium ions wherein a phosphorus atom is bonded to four alkyl groups containing 2 to 4 carbon atoms.

Claim 30

An amorphous silica as defined in claim 13, 16, 17, or 18 having catalytic activity for isomerizing ortho-xylene to para-xylene and meta-xylene at 900° F. and atmospheric pressure at a rate of at least 2.0×10 10 molecules of ortho-xylene converted per second per square centimeter of surface area of said amorphous silica.

Claim 31

An amorphous silica as defined in claim 13, 16, 17, or 18 having catalytic activity for isomerizing ortho-xylene to para-xylene and meta-xylene at 900° F. and atmospheric pressure at a rate of at least 3.0×10 10 molecules of ortho-xylene converted per second per square centimeter of surface area of said amorphous silica.

Claim 32

An amorphous silica as defined in claim 13, 14, 16, 17, or 18 having catalytic activity for isomerizing ortho-xylene to para-xylene and meta-xylene at 900° F. and atmospheric pressure at a rate of at least 4.0×10 10 molecules of ortho-xylene converted per second per square centimeter of surface area of said amorphous silica.

Claim 33

An amorphous silica as defined in claim 13, 14, 16, or 17 having catalytic activity for isomerizing ortho-xylene to para-xylene and meta-xylene at 900° F. and atmospheric pressure at a rate of at least 1.0×10 10 molecules of ortho-xylene converted per second per square centimeter of surface area of said amorphous silica.