Abstract: Disclosed is a process for modifying accumulated cross-linked polymer in an apparatus used for the production of a vinylaromatic compound, comprising optionally softening the polymer with an organic solvent; precipitating the polymer with a light, polar non-solvent for the polymer and expanding the softened polymer by bringing the softened polymer in contact with steam whereby the polymer is converted into a state which enables it to be more easily removed from the apparatus.

Abstract: Process for removing the nitrogen impurities from a liquid hydrocarbon mixture comprising introducing into a low volume mixer the hydrocarbons to be treated together with a dilute aqueous acid solution to form an emulsion, withdrawing said emulsion into a decantation zone where it breaks and recycling to the low volume mixer from 80 to 95% by volume of the aqueous acid solution coming from the decantation zone, so as to maintain in said low volume mixer a volume ratio of the hydrocarbons to the aqueous acid solution from about 0.3 to about 13, preferably from about 0.5 to about 4, and the pH of the aqueous acid solution from about 0.1 to about 1.5.

Abstract: A method for controlling the formation of polymer accumulations in a distillation column comprising accumulating liquid phase material containing a polymerization inhibitor in a seal pan; providing the seal pan with liquid-pervious weep hole means through the bottom of the pan and allowing a controlled quantity of polymerization inhibitor-containing liquid phase material to seep through the weep hole means to the underside of the seal pan; and apparatus useful for practicing the disclosed method.

Abstract: Formation of undesired by-product adduct during production of acrylonitrile-butadiene-styrene-acrylate copolymers is controlled by subjecting the inhibitor containing reaction mixture to a molecular-oxygen-containing gaseous atmosphere during addition of the acrylate monomer.

Abstract: A process for distilling vinyltoluene comprising subjecting vinyltoluene to distillation conditions in the presence of a synergistic polymerization inhibiting mixture of N-nitrosodiphenylamine (NDPA) and dinitro-para-cresol (DNPC). Preferably from about 100 to about 300 ppm by weight NDPA and about 300 to about 700 ppm by weight DNPC are dissolved in the crude vinyltoluene and the resulting solution is vacuum distilled.