Abstract: Mono or dicarboxylic acids containing from two to four carbon atoms are extracted from dilute aqueous solutions with an organic liquid comprising one or more of the following extractants: dialkyl alkyl phosphonates, alkyl dialkyl phosphinates, trialkyl phosphine oxides, dialkyl alicyclic amidophosphates, dialkyl sulfoxides and tetralkyl ureas. An improved method for removing carboxylic acid contaminants from aqueous effluents or recycle streams is provided.

Abstract: Mono or dicarboxylic acids containing from two to four carbon atoms are extracted from dilute aqueous solutions with an organic liquid comprising one or more of the following extractants: dialkyl alkyl phosphonates, alkyl dialkyl phosphinates, trialkyl phosphine oxides, dialkyl alicyclic amidophosphates, dialkyl sulfoxides and tetralkyl ureas. An improved method for removing carboxylic acid contaminants from aqueous effluents or recycle streams is provided.

Abstract: Mono or dicarboxylic acids containing from two to four carbon atoms are extracted from dilute aqueous solutions with an organic liquid comprising one or more of the following extractants: dialkyl alkyl phosphonates, alkyl dialkyl phosphinates, trialkyl phosphine oxides, dialkyl alicyclic amidophosphates, dialkyl sulfoxides and tetralkyl ureas. An improved method for removing carboxylic acid contaminants from aqueous effluents or recycle streams is provided.

Abstract: Mono or dicarboxylic acids containing from two to four carbon atoms are extracted from dilute aqueous solutions with an organic liquid comprising one or more of the following extractants: dialkyl alkyl phosphonates, alkyl dialkyl phosphinates, trialkyl phosphine oxides, dialkyl alicyclic amidophosphates, dialkyl sulfoxides and tetralkyl ureas. An improved method for removing carboxylic acid contaminants from aqueous effluents or recycle streams is provided.

Abstract: The invention comprises a process for producing ring-perchlorinated aromatic carbocyclic and N-heterocyclic isocyanates by the vapor phase chlorination of the corresponding acetamido-substituted carbocycle or N-heterocycle. The resulting isocyanate may be further reacted with an active hydrogen-containing compound to form the corresponding carbamate, thiocarbamate, urea, or the like. The invention further comprises certain novel compounds made by such process, said compounds being useful as intermediates for plastic materials or as fine retardant additives in plastics.