Abstract: The present invention provides an improvement in methods for preparing and processing ethylenically unsaturated aromatic monomer. The improvement comprises employing 3,5-dinitrosalicylic acid or a derivative or isomer thereof as a process inhibitor. The process inhibitor is present in a concentration of about 50 to 3000 ppm, preferably about 250 to 2,000 ppm, and most preferably about 500 to 1,000 ppm.

Abstract: The present invention provides an improvement in methods for preparing and processing ethylenically unsaturated aromatic monomer. The improvement comprises employing 3,5-dinitrosalicylic acid as a process inhibitor. The DNSA is present in a concentration of about 50 to 3000 ppm, preferably about 250 to 2000 ppm, and most preferably about 500 to 1000 ppm.

Abstract: polyurethane foams are stabilized against scorching when a mixture of hydroquinone and a phosphite containing secondary antioxidant is present in a foam-forming mixture of an organic polyisocyanate with a polyether polyol in the presence of a reaction catalyst and a foaming agent. The proportion of hydroquinone to the phosphite is in the range of 10:1 to about 1:1. Especially advantageous results can be obtained by adding p,p'-dialkylphenylamines containing between 3 and 18 carbon atoms in the alkyl moiety to the above two stabilizers. When the amine is present the stabilizer mixture usually comprises between about 15 and 90% by weight of the amine and the rest of the stabilizer comprises the hydroquinone and the phosphite in the range relative to each other as given above. The proportion of the stabilizer mixture is usually between about 10 and about 50,000 parts per million parts of the polyether polyol.

Abstract: metal chelating agents such as citric acid can be used to reduce color formation and decomposition of p-benzoquinone containing from 0.1% to 18% moisture level.