The issues around waste plastic have gained global attention, and many Value Chain Partners are working towards a plastic’s circular economy. Dow has evaluated multiple pyrolysis oil samples produced around the world from waste plastics as a potential circular feedstock. Typically, these have been found not suitable to be used as a drop-in replacement of fossil-naphtha to produce circular plastics. To facilitate application of such oils as a circular feedstock, a much better understanding of the pyrolysis oil composition is required. This calls for the development of more advanced characterization techniques to identify a variety of hydrocarbons as well as organic molecules with hetero-atoms such as Cl, O, and/or N. Pyrolysis oils originating from waste plastic are extremely complex and contain unsaturated hydrocarbons which are not present in fossil feedstocks. Therefore, detailed hydrocarbon analysis (DHA) or GCxGC with FID detection is inadequate to fully characterize the hydrocarbon composition of such samples, especially when peaks are closely eluting, or even co-eluting. In this study, the GC-VUV method previously described for the analysis of liquid hydrocarbon streams has been applied to the analysis of pyrolysis oils. GC-VUV is a relatively newly commercialized technique for the quantification of hydrocarbon composition in samples, allowing for identification and quantification in a PIONA-like fashion based on the UV spectra when the VUV PIONA+ software is utilized. This presentation will focus on the GC-VUV evaluation of pyrolysis oils, with emphasis on the enhanced accuracy of the hydrocarbon group identification. Pyrolysis products are also rich in oxygen containing hydrocarbons, and commercially available methods are restricted within C1 and C5 oxygenates. To obtain a better understanding of the oxygenate composition, GCxGC coupled to Time of Flight Mass Spectrometry (TOF-MS) was used and preliminary results will be shown.

Advancing the circular economy of plastics with advanced gas chromatographic techniques: GC-VUV and GCxGC-TOFMS

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.