The present invention relates to a catalyst system for oxidation of o-xylene and/or naphthalene to phthalic anhydride (PA) comprising at least four catalyst zones arranged in succession in the reaction tube and filled with catalysts of different chemical composition wherein the active material of the catalysts comprise vanadium and titanium dioxide and the active material of the catalyst in the last catalyst zone towards the reactor outlet has an antimony content (calculated as antimony trioxide) between 0.7 to 3.0 wt. %. The present invention further relates to a process for gas phase oxidation in which a gas stream comprising at least one hydrocarbon and molecular oxygen is passed through a catalyst system which comprises at least four catalyst zones arranged in succession in the reaction tube and filled with catalysts of different chemical composition wherein the active materials of the catalysts comprise vanadium and titanium dioxide and the active material of the catalyst in the last catalyst zone towards the reactor outlet has an antimony content (calculated as antimony trioxide) between 0.7 to 3.0 wt. %.

The present invention relates to a catalyst system for oxidation of o-xylene and/or naphthalene to phthalic anhydride (PA) comprising at least four catalyst zones arranged in succession in the reaction tube and filled with catalysts of different chemical composition wherein the active material of the catalysts comprise vanadium and titanium dioxide and the active material of the catalyst in the last catalyst zone towards the reactor outlet has an antimony content (calculated as antimony trioxide) between 0.7 to 3.0 wt. %. The present invention further relates to a process for gas phase oxidation in which a gas stream comprising at least one hydrocarbon and molecular oxygen is passed through a catalyst system which comprises at least four catalyst zones arranged in succession in the reaction tube and filled with catalysts of different chemical composition wherein the active materials of the catalysts comprise vanadium and titanium dioxide and the active material of the catalyst in the last catalyst zone towards the reactor outlet has an antimony content (calculated as antimony trioxide) between 0.7 to 3.0 wt. %.

Disclosed are methods to produce Thermal Barrier Coating (TBC) products using materials recycled from TBC waste. These methods include ways to produce zirconium and rare earth chemicals and raw materials appropriate for producing TBC materials.

Disclosed are methods to produce Thermal Barrier Coating (TBC) products using materials recycled from TBC waste. These methods include ways to produce zirconium and rare earth chemicals and raw materials appropriate for producing TBC materials.

The modified graphene includes a structure represented by the following formula (I), wherein the modified graphene has a ratio (g/d) of an intensity “g” of a G band to an intensity “d” of a D band of 1.0 or more in a Raman spectroscopy spectrum thereof:
Gr1-Ar1-X1-(Y1).sub.n1  (I)
in the formula (I), Gr1 represents a single-layer graphene or a multilayer graphene, Ar1 represents an arylene group having 6 to 18 carbon atoms, X1 represents a single bond, a linear, branched, or cyclic alkylene group having 1 to 20 carbon atoms, or a group obtained by substituting at least one carbon atom in a linear, branched, or cyclic alkylene group having 1 to 20 carbon atoms with at least one structure selected from the group consisting of —O—, —NH—, ##STR00001##
—CO—, —COO—, —CONH—, and an arylene group.

The modified graphene includes a structure represented by the following formula (I), wherein the modified graphene has a ratio (g/d) of an intensity “g” of a G band to an intensity “d” of a D band of 1.0 or more in a Raman spectroscopy spectrum thereof:
Gr1-Ar1-X1-(Y1).sub.n1  (I)
in the formula (I), Gr1 represents a single-layer graphene or a multilayer graphene, Ar1 represents an arylene group having 6 to 18 carbon atoms, X1 represents a single bond, a linear, branched, or cyclic alkylene group having 1 to 20 carbon atoms, or a group obtained by substituting at least one carbon atom in a linear, branched, or cyclic alkylene group having 1 to 20 carbon atoms with at least one structure selected from the group consisting of —O—, —NH—, ##STR00001##
—CO—, —COO—, —CONH—, and an arylene group.

A method of production of malic acid includes treating a first intermediate product to form a second intermediate product. The treating includes substantially removing impurities from the first intermediate product to obtain a treated intermediate product by gas stripping the crude maleic anhydride, or subjecting a mixture of one or more of the crude maleic acid, the crude fumaric acid, and the vent gas scrubber solution obtained from a phthalic anhydride production process or a maleic anhydride production process to crystallization, passing an aqueous solution of the treated intermediate product through a carbon column to substantially remove retained impurities to form the second intermediate product, obtaining a feed that includes the second intermediate product, and causing the feed to undergo hydration reaction in a tubular reactor or a continuous stirred tank reactor to produce malic acid.

A method of production of malic acid includes treating a first intermediate product to form a second intermediate product. The treating includes substantially removing impurities from the first intermediate product to obtain a treated intermediate product by gas stripping the crude maleic anhydride, or subjecting a mixture of one or more of the crude maleic acid, the crude fumaric acid, and the vent gas scrubber solution obtained from a phthalic anhydride production process or a maleic anhydride production process to crystallization, passing an aqueous solution of the treated intermediate product through a carbon column to substantially remove retained impurities to form the second intermediate product, obtaining a feed that includes the second intermediate product, and causing the feed to undergo hydration reaction in a tubular reactor or a continuous stirred tank reactor to produce malic acid.

The modified graphene includes a structure represented by the following formula (I), wherein the modified graphene has a ratio (g/d) of an intensity “g” of a G band to an intensity “d” of a D band of 1.0 or more in a Raman spectroscopy spectrum thereof.

Gr1-Ar1-X1-(Y1).sub.n1  (I)

in the formula (I), Gr1 represents a single-layer graphene or a multilayer graphene, Ar1 represents an arylene group having 6 to 18 carbon atoms, X1 represents a single bond, a linear, branched, or cyclic alkylene group having 1 to 20 carbon atoms, or a group obtained by substituting at least one carbon atom in a linear, branched, or cyclic alkylene group having 1 to 20 carbon atoms with at least one structure selected from the group consisting of —O—, —NH—,

##STR00001##

—CO—, —COO—, —CONH—, and an arylene group.

The modified graphene includes a structure represented by the following formula (I), wherein the modified graphene has a ratio (g/d) of an intensity “g” of a G band to an intensity “d” of a D band of 1.0 or more in a Raman spectroscopy spectrum thereof.

Gr1-Ar1-X1-(Y1).sub.n1  (I)

in the formula (I), Gr1 represents a single-layer graphene or a multilayer graphene, Ar1 represents an arylene group having 6 to 18 carbon atoms, X1 represents a single bond, a linear, branched, or cyclic alkylene group having 1 to 20 carbon atoms, or a group obtained by substituting at least one carbon atom in a linear, branched, or cyclic alkylene group having 1 to 20 carbon atoms with at least one structure selected from the group consisting of —O—, —NH—,

##STR00001##

—CO—, —COO—, —CONH—, and an arylene group.