A method for decomposing a nitroso compound, comprising: adding an aqueous solution containing hydrogen halide to a liquid to be treated that contains the nitroso compound in such a manner that the hydrogen halide is present in an amount of 2 mol or more and 20 mol or less per mol of a nitroso group in the nitroso compound; and subsequently heating the resulting liquid to be treated at a temperature of not lower that 75° C. and not higher than a boiling point of water under ordinary pressure, thereby an amines are recovered.

A method for decomposing a nitroso compound, comprising: adding an aqueous solution containing hydrogen halide to a liquid to be treated that contains the nitroso compound in such a manner that the hydrogen halide is present in an amount of 2 mol or more and 20 mol or less per mol of a nitroso group in the nitroso compound; and subsequently heating the resulting liquid to be treated at a temperature of not lower that 75° C. and not higher than a boiling point of water under ordinary pressure, thereby an amines are recovered.

Methods of synthesizing and purifying certain 3,7-diamino-phenothiazin-5-ium compounds (referred to herein as “diaminophenothiazinium compounds”) including Methythioninium Chloride (MTC) (also known as Methylene Blue) are provided. ##STR00001##

Methods of synthesizing and purifying certain 3,7-diamino-phenothiazin-5-ium compounds (referred to herein as “diaminophenothiazinium compounds”) including Methythioninium Chloride (MTC) (also known as Methylene Blue) are provided. ##STR00001##

Provided is a catalyst mixture which, in a nitro group hydrogenation reaction of an aromatic nitro compound having a structure in which nitro groups and halogen atoms are directly bonded as substituents to a ring skeleton of the same ring while separated from each other, is capable of selectively hydrogenating the nitro groups and sufficiently reducing the removal of the halogen atoms from the ring. This catalyst mixture includes a catalyst which is used in a hydrogenation reaction of at least one among one or more nitro groups present in a reactant, which is an aromatic nitro compound having a structure in which one or more nitro groups and one or more halogen atoms are directly bonded as substituents to a ring skeleton of the same ring while separated from each other. This catalyst mixture further includes a base.

A method for decomposing a nitroso compound, comprising: adding an aqueous solution containing hydrogen halide to a liquid to be treated that contains the nitroso compound in such a manner that the hydrogen halide is present in an amount of 2 mol or more and 20 mol or less per mol of a nitroso group in the nitroso compound; and subsequently heating the resulting liquid to be treated at a temperature of not lower that 75 C. and not higher than a boiling point of water under ordinary pressure, thereby an amines are recovered.

A method for decomposing a nitroso compound, comprising: adding an aqueous solution containing hydrogen halide to a liquid to be treated that contains the nitroso compound in such a manner that the hydrogen halide is present in an amount of 2 mol or more and 20 mol or less per mol of a nitroso group in the nitroso compound; and subsequently heating the resulting liquid to be treated at a temperature of not lower that 75 C. and not higher than a boiling point of water under ordinary pressure, thereby an amines are recovered.

Methods of synthesizing and purifying certain 3,7-diamino-phenothiazin-5-ium compounds (referred to herein as diaminophenothiazinium compounds) including Methythioninium Chloride (MTC) (also known as Methylene Blue) are provided.

##STR00001##

Methods of synthesizing and purifying certain 3,7-diamino-phenothiazin-5-ium compounds (referred to herein as diaminophenothiazinium compounds) including Methythioninium Chloride (MTC) (also known as Methylene Blue) are provided.

##STR00001##

Methods of synthesizing and purifying certain 3,7-diamino-phenothiazin-5-ium compounds (referred to herein as diaminophenothiazinium compounds) including Methythioninium Chloride (MTC) (also known as Methylene Blue) are provided.

##STR00001##