Abstract: Polymerization inhibitor compositions are provided. The polymerization inhibitor compositions include at least a first inhibitor compound having a stable nitroxide radical or a derivative thereof, a second inhibitor compound having a phenothiazine or a derivative thereof, and a functional solvent. Methods of inhibiting the polymerization of monomers using the compositions of the disclosure are also provided. The methods of inhibiting polymerization of monomers include a step of adding a composition of the disclosure to the monomer. In some instances, the monomer is an ethylenically unsaturated monomer. Such ethylenically unsaturated monomers include, but are not limited to, (meth)acrylic acid, methyl methacrylate, acrylic acid, acrylic acid esters, methacrylamide sulfate, vinyl acetate, acrylonitrile, acrolein, acrylates, methacrylates, 1,3-butadiene, styrene, isoprene, and combinations thereof. Methods of preparing the polymerization inhibitors and compositions of the disclosure are also provided.

Abstract: Polymerization inhibitor compositions are provided. The polymerization inhibitor compositions include at least a first inhibitor compound having a phenothiazine or a derivative thereof, a second inhibitor compound having a phenylenediamine or a derivative thereof, and a solvent. Methods of inhibiting the polymerization of monomers using the compositions of the disclosure are also provided. The methods of inhibiting polymerization of monomers include a step of adding a composition of the disclosure to the monomer. In some instances, the monomer is an ethylenically unsaturated monomer. Such ethylenically unsaturated monomers include, but are not limited to, (meth)acrylic acid, methyl methacrylate, acrylic acid, acrylic acid esters, methacrylamide sulfate, vinyl acetate, acrylonitrile, acrolein, acrylates, methacrylates, 1,3-butadiene, styrene, isoprene, and combinations thereof. Methods of preparing the polymerization inhibitors and compositions of the disclosure are also provided.

Abstract: The present disclosure relates to various testing methods that can be applied to oils, such as pyrolysis oils. Different testing methods can be used to determine the oxidative stability of an oil. The testing methods may also be used to differentiate between various oils and to determine the effectiveness of various antioxidants on the oxidative stability of an oil.

Abstract: Disclosed are antifouling agents used in compositions and methods to reduce or prevent foulants in synthetic feedstocks derived from plastic. A method of reducing or preventing fouling in a plastic-derived synthetic feedstock composition may include adding an antifouling agent including a carboxylic acid anhydride or a copolymer of a dicarboxylic acid anhydride and alpha olefin to a synthetic feedstock composition derived from plastic pyrolysis containing a foulant to provide treated pyrolysate. The foulant may include, for example, nylon, polyvinyl chlorides, polyethylene terephthalate, polyamides, caprolactam, benzoic acid, phenol, p-cresol, dimethylphenol, isopropyl phenol, tert-butylphenol, dimethylethylphenol, napthalenol, varying lengths of alkenes and alkanes, propylene, tolune, pentene, butane, tetramethylindole, ethylbenzene, ethyldimethylpyrrole, dimethylfuran, tetrahydroquinoline, and any combination thereof.

Abstract: Disclosed are extraction solvents used in compositions and methods to refine synthetic feedstocks derived from plastic. Methods of refining plastic-derived synthetic feedstocks are also provided. For example, a method of refining a plastic-derived synthetic feedstock composition may include adding an extraction solvent to a synthetic feedstock composition derived from plastic pyrolyis to provide an extract phase and a raffinate phase, wherein the extraction solvent includes a polar organic extraction solvent immiscible in the synthetic feedstock. The methods may also include separating the raffinate phase from the extract phase to obtain a refined synthetic feedstock.

Abstract: Disclosed are antioxidants used in compositions and methods to stabilize synthetic feedstock derived from plastic. Some methods disclosed herein include adding an antioxidant composition to a plastic-derived synthetic feedstock composition. Some methods disclosed herein include heating plastic under substantially oxygen free conditions at a temperature of from about 400° C. to about 800° C. to produce a pyrolysis effluent, distilling the pyrolysis effluent, recovering the synthetic feedstock, and adding a stabilizer to the synthetic feedstock to reduce contamination. The disclosure also provides compositions including a synthetic feedstock derived from plastic and an antioxidant.