Methods of producing organic materials, and in particular methods of producing petroleum materials and organic compounds such as aromatic acids, phenols, and aliphatic poly-carboxylic acids using an oxidative hydrothermal dissolution (OHD) process are disclosed.

Methods of producing organic materials, and in particular methods of producing petroleum materials and organic compounds such as aromatic acids, phenols, and aliphatic poly-carboxylic acids using an oxidative hydrothermal dissolution (OHD) process are disclosed.

The present invention relates to semiaromatic semicrystalline thermoplastic copolyimides obtained by polymerization of at least: (a) an aromatic compound comprising two anhydride functions and/or carboxylic acid and/or ester derivatives thereof; (b) a diamine of formula (I) NH2RNH2 in which R is a divalent aliphatic hydrocarbon-based radical optionally comprising heteroatoms, the two amine functions being separated by a number X of carbon atoms, X being between 4 and 12; and (c) a diamine of formula (II) NH2RNH2 in which R is a divalent aliphatic hydrocarbon-based radical optionally comprising heteroatoms, the two amine functions being separated by a number Y of carbon atoms, Y being between 10 and 20; it being understood that diamine (b) is different from diamine (c).

The present invention relates to semiaromatic semicrystalline thermoplastic copolyimides obtained by polymerization of at least: (a) an aromatic compound comprising two anhydride functions and/or carboxylic acid and/or ester derivatives thereof; (b) a diamine of formula (I) NH2RNH2 in which R is a divalent aliphatic hydrocarbon-based radical optionally comprising heteroatoms, the two amine functions being separated by a number X of carbon atoms, X being between 4 and 12; and (c) a diamine of formula (II) NH2RNH2 in which R is a divalent aliphatic hydrocarbon-based radical optionally comprising heteroatoms, the two amine functions being separated by a number Y of carbon atoms, Y being between 10 and 20; it being understood that diamine (b) is different from diamine (c).

Provided is a method of producing an anhydride of an organic mono-acid comprising contacting an organic mono-acid and a thermally regenerable anhydride to produce the anhydride of the organic mono-acid, and either a diacid of the regenerable anhydride, a partially hydrolyzed regenerable anhydride, or both. In a particular example, acetic acid and glutaric anhydride can be reacted to form acetic anhydride.

Provided is a method of producing an anhydride of an organic mono-acid comprising contacting an organic mono-acid and a thermally regenerable anhydride to produce the anhydride of the organic mono-acid, and either a diacid of the regenerable anhydride, a partially hydrolyzed regenerable anhydride, or both. In a particular example, acetic acid and glutaric anhydride can be reacted to form acetic anhydride.