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 process for extracting aromatic dicarboxylic acids from an outlet stream of a basic depolymerization of polycondensates containing metal carboxylates of the aromatic dicarboxylic acid to be extracted, wherein a mineral or organic acid is added to this outlet stream, the pKs value of which acid being greater than or equal to that of the aromatic dicarboxylic acid, on which the polycondensate is based.

The present invention relates to a process for extracting aromatic dicarboxylic acids from an outlet stream of a basic depolymerization of polycondensates containing metal carboxylates of the aromatic dicarboxylic acid to be extracted, wherein a mineral or organic acid is added to this outlet stream, the pKs value of which acid being greater than or equal to that of the aromatic dicarboxylic acid, on which the polycondensate is based.

Provided are methods for the production of phthalic acid (PA), isophthalic acid (IP A), terephthalic acid (TP A), and derivatives thereof. The methods are based on the addition of beta propiolactone to furfural or a derivative thereof. Provided are cost effective routes to biobased IP A and derivatives thereof, including terephthalic acid.

Provided are methods for the production of phthalic acid (PA), isophthalic acid (IP A), terephthalic acid (TP A), and derivatives thereof. The methods are based on the addition of beta propiolactone to furfural or a derivative thereof. Provided are cost effective routes to biobased IP A and derivatives thereof, including terephthalic acid.

Provided are methods for the production of isophthalic acid (IP A) and derivatives thereof. The methods are based on the addition of beta propiolactone to furfural or a derivative thereof. Provided are cost effective routes to biobased IP A and derivatives thereof, including terephthalic acid.

Provided are methods for the production of isophthalic acid (IP A) and derivatives thereof. The methods are based on the addition of beta propiolactone to furfural or a derivative thereof. Provided are cost effective routes to biobased IP A and derivatives thereof, including terephthalic 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.

Provided are methods for the production of isophthalic acid (IP A) and derivatives thereof. The methods are based on the addition of beta propiolactone to furfural or a derivative thereof. Provided are cost effective routes to biobased IP A and derivatives thereof, including terephthalic acid.