Abstract: Described is a continuous process for preparing indolenine compounds which comprises charging continuously and simultaneously to a reactor containing an acetic acid reaction medium (1) substituted phenylhydrazine and (2) unsymmetrical ketone from separate sources, continuously discharging from the reactor indolenine product in acetic acid solution, separating acetic acid from the indolenine product, recycling separated acetic acid to the reactor, neutralizing residual acetic acid remaining in the indolenine product with aqueous inorganic alkaline reagent, and separating from the indolenine product an aqueous solution of salts resulting from the preparation and neutralization of the indolenine product.

Abstract: Disclosed is a method for selectively separating 2-nitrosophenol from an isomeric mixture containing 2-nitrosophenol and 4-nitrosophenol by contacting the mixture with an organic solvent so as to preferentially dissolve the 2-nitrosophenol from the mixture.

Abstract: Described is photochromic particulate material comprising a photochromic substance within a matrix of a polymerizate of a polyfunctional acrylate monomer. The photochromic particulate material may be produced by adding an organic photochromic substance to a polymerizable composition including a polyfunctional acrylate monomer and polymerizing the resultant admixture, e.g., by emulsion polymerization. In the case of emulsion or suspension polymerization, finely divided particulate organic photochromic materials are separated from the polymerization medium in the form of spheroidal thermoset photochromic particles of fairly uniform size. If desired, the particles recovered from the polymerization medium may be further ground in conventional attrition mills to further reduce the size of the particulate product. In the case of bulk polymerization, the polymerizate may be formed as a continuously cast sheet, which is then pulverized to a particulate material of pigmentary size.

Abstract: Spiro(indoline)-type photochromic compounds are prepared by admixing a solution of the Fischer's Base reactant in non-polar solvent with a mixture of the pyran- or oxazine-forming reactant, e.g., 5-nitroso-6-hydroxy quinoline, in polar solvent and heating the resulting reaction medium at temperatures sufficient to form the corresponding spiro(indoline)-type compound while simultaneously removing co-product water.

Abstract: Disclosed is a process of producing anhydrous sodium dithionite by contacting sulfur dioxide-containing formamide and sodium amalgam, separating a sodium dithionite-containing formamide solution from the sodium amalgam and precipitating anhydrous sodium dithionite from the product formamide solution by mixing the sodium dithionite-containing formamide solution with isopropanol, n-propanol, gamma-butyrolactone, tetrahydrofuran or N-methyl-2-pyrrolidone. The sulfur dioxide may be contacted countercurrently with the sodium amalgam in a continuous process. A neutralizing agent can optionally be added to the sodium dithionite-containing formamide solution separated from the amalgam to reduce acidic decomposition of the sodium dithionite.

Abstract: Disclosed is a solubility stable bleaching formulation in the form of an encapsulated core. The core comprises particles of tabular habit diperisophthalic acid (DPI) in admixture with particles of inorganic salt substantially more water-soluble than the diperisophthalic acid. The bleaching formulation maintains a high rate of solution in water after storage under conditions of temperature fluctuation.