Abstract: A method and apparatus for quantitatively monitoring a chemical component dissolved in a liquid medium utilize the creation, in a measurement cell, of an interface zone between the liquid medium and an analytical reagent or reference solution. The concentration or amount of the chemical component are determined by the measurement of a value of a measurement parameter in the interface zone, and the derivation from that value of the concentration or amount of the component in comparison with a baseline or reference value measured for the reagent or reference solution alone. Matrix effects and ghosting errors are avoided. The method and apparatus can be used advantageously for on-line optimization and control of industrial, chemical and biological processes, such as chemical reactions in progress, coupling reactions for the synthesis of azo compounds, and the monitoring of in vivo or in vitro biological systems as well as for conventional analytical purposes.

Abstract: An organic pigment dispersion in a non-aqueous medium is prepared directly from an aqueous slurry containing 0.1-20% by weight of the pigment by mixing the aqueous slurry with the non-aqueous medium under vigorous agitation and subsequently isolating the organic pigment dispersion from the residual aqueous phase.A substantial part of water in the resulting pigment dispersion can be removed by passing the organic pigment dispersion in the non-aqueous medium over a series of surfaces, the surface material thereof having different affinity for water and the non-aqueous medium, respectively, and then removing water and pigment dispersion in the non-aqueous medium, respectively, from respective surfaces.

Abstract: Azopigments resulting from coupling a diazoaryl compound with an acetoacetic acid derivative having a quaternary ammonium group linked to the terminal methyl group show increased color strength and improved stability on storing as compared with the corresponding azopigments not having the said quaternary ammonium group in the molecule. For example, 2-nitro-4-chloro phenyldiazonium chloride or dichlorobenzidinetertrazonium chloride is coupled with an omega-ammoniumacetic acid derivative. The arylide azopigments of the present invention can be used in printing inks.

Abstract: An agent for enhancing the fluidity of pigment dispersions comprising a composition of disazo compounds containing a water-insoluble disazo compound in which one of the terminal aromatic groups carries a single substituted ammonium-acid salt group, pigments treated with the agent and non-aqueous pigment dispersions containing the agent.