A method for chlorinating blue anthrone, violanthrone or isoviolanthrone is provided. Reaction is carried out with a chlorinating agent (any one of sulfonyl chloride, thionyl chloride and triphosgene) in a reaction solvent (a Lewis acid ionic liquid with anions being of a transition metal halide) for 2 h to 40 h at a chlorination temperature not lower than room temperature and not higher than 120° C.; and then the reaction product is subjected to post-treatment to obtain a target product. The present disclosure cuts off a generation route of harmful substances such as dioxins and their derivatives from the source. There are no dioxins or similar substances generated in the product, and the reaction has high atomic utilization rate and low energy consumption, which fills the gap in the field of chemical technologies at home and abroad.

The present disclosure provides stabilized hematoxylin formulations having a pH of less than 2.4. The present disclosure also provides methods of using such stabilized hematoxylin formulations to stain biological samples.

Methods and compositions for removing precipitates or reducing the formation of precipitates generated in hematoxylin solutions. The methods and compositions feature cleaning solutions that feature chemical compounds that initiate processes including but not limited to acidification of the waste solution, chelation of metal ions in the waste solution, reduction reactions, oxidation reactions, and metal salt addition reactions.

Methods and compositions for removing precipitates or reducing the formation of precipitates generated in hematoxylin solutions. The methods and compositions feature cleaning solutions that feature chemical compounds that initiate processes including but not limited to acidification of the waste solution, chelation of metal ions in the waste solution, reduction reactions, oxidation reactions, and metal salt addition reactions.

The present invention relates to a technique for providing a quinacridone solid solution pigment, by which a quinacridone solid solution pigment that allows a colored product to have high chroma and a properly yellowish hue, and suitably, that has a controlled particle diameter and has the above-described, desired hue can be obtained. The present invention provides a method for producing a quinacridone solid solution pigment, wherein a diarylaminoterepththalic acid and a dialkylarylaminoterephthalic acid are subjected to a co-cyclization reaction in polyphosphoric acid, thereby obtaining a water-containing crude quinacridone solid solution such that water is contained in a solid solution having a mass ratio of unsubstituted quinacridone to a 2,9-dialkylquinacridone of 85:15 to 60:40; the water-containing crude quinacridone solid solution obtained above is dried in a drying step, thereby obtaining a powdery, crude quinacridone solid solution having a water content of less than 1%; and the powdery, crude quinacridone solid solution is heated in a liquid medium that does not dissolve the crude quinacridone solid solution in a pigmentation step, and the present invention also provides a pigment dispersion liquid and an inkjet ink each containing the obtained quinacridone solid solution pigment.

A method for chlorinating blue anthrone, violanthrone or isoviolanthrone is provided. Reaction is carried out with a chlorinating agent (any one of sulfonyl chloride, thionyl chloride and triphosgene) in a reaction solvent (a Lewis acid ionic liquid with anions being of a transition metal halide) for 2 h to 40 h at a chlorination temperature not lower than room temperature and not higher than 120? C.; and then the reaction product is subjected to post-treatment to obtain a target product. The present disclosure cuts off a generation route of harmful substances such as dioxins and their derivatives from the source. There are no dioxins or similar substances generated in the product, and the reaction has high atomic utilization rate and low energy consumption, which fills the gap in the field of chemical technologies at home and abroad.

A quinacridone solid solution pigment that allows a colored product to have high chroma and a properly yellowish hue and has a controlled particle diameter, and a method for producing the quinacridone solid solution pigment. In the method, a water-containing crude quinacridone solid solution is produced by a co-cyclization reaction of a diarylaminoterepththalic acid and a dialkylarylaminoterephthalic acid in polyphosphoric acid, then the resulting water-containing crude quinacridone solid solution having a mass ratio of unsubstituted quinacridone to a 2,9-dialkylquinacridone of 85:15 to 60:40 is dried, thereby obtaining a powdery, crude quinacridone solid solution having a water content of less than 1%. Then, the resulting powdery, crude quinacridone solid solution is heated in a liquid medium that does not dissolve the crude quinacridone solid solution. Also, a pigment dispersion liquid and an inkjet ink each containing the obtained quinacridone solid solution pigment are provided.

The present invention provides a method for preserving a leuco chromogen-containing aqueous solution comprising: adding at least one acid compound selected from the group consisting of a phosphoric acid compound, a carboxylic acid compound, a sulfonic acid compound, and a sulfuric acid compound to a leuco chromogen-containing aqueous solution; a method for stabilizing a leuco chromogen in an aqueous solution comprising: adding at least one acid compound selected from the group consisting of a phosphoric acid compound, a carboxylic acid compound, a sulfonic acid compound, and a sulfuric acid compound to a leuco chromogen-containing aqueous solution; and a liquid reagent comprising a leuco chromogen and at least one acid compound selected from the group consisting of a phosphoric acid compound, a carboxylic acid compound, a sulfonic acid compound, and a sulfuric acid compound.

The present invention provides a method for preserving a leuco chromogen-containing aqueous solution comprising: adding at least one acid compound selected from the group consisting of a phosphoric acid compound, a carboxylic acid compound, a sulfonic acid compound, and a sulfuric acid compound to a leuco chromogen-containing aqueous solution; a method for stabilizing a leuco chromogen in an aqueous solution comprising: adding at least one acid compound selected from the group consisting of a phosphoric acid compound, a carboxylic acid compound, a sulfonic acid compound, and a sulfuric acid compound to a leuco chromogen-containing aqueous solution; and a liquid reagent comprising a leuco chromogen and at least one acid compound selected from the group consisting of a phosphoric acid compound, a carboxylic acid compound, a sulfonic acid compound, and a sulfuric acid compound.

Provided is a compound with a high biomass ratio (preferably a compound with a biomass ratio of 100%) obtained by using a natural pigment and having excellent color developability and light resistance. The compound is a compound in which a natural pigment of curcumin is bound to an organic acid has a number average molecular weight (Mn) of 400 to 4,950.