Polycyclic aromatic hydrocarbons (PAHs) are a group of more than hundred compounds that are ubiquitous in our environment. Some of these PAHs are known to be carcinogenic, mutagenic and teratogenic. PAHs have been detected in dried herbs that were cultured in The Netherlands as well as in other European countries above the maximum levels in dried herbs set by the EU (EU, 2015) for benzo(a)pyrene and the sum of the following four PAHs benzo(a)pyrene, benzo[a]anthracene, benzo[b]fluoranteen and chrysene. The origin of these PAHs in herbs is unknown. VNK cultivates, harvests and dries herbs including valerian and would like to identify the source of PAHs to comply to the EU limits for PAHs in herbs. The goal of the present study was to identify the source of PAHs found in valerian root, and to identify possible measures to reduce the concentration of PAHs in valerian root.
MULTIFILE
The present invention relates to a novel process for the preparation of low molecular weight aromatic compounds such as benzene, toluene, and xylenes (BTX) from plastics. Provided is a thermo-catalytic pyrolysis process for the preparation of aromatic compounds from a feed stream comprising plastic, comprising the steps of: a) subjecting a feed stream comprising a plastic to a pyrolysis treatment at a pyrolysis temperature in the range of 600-1000°C to produce pyrolysis vapors; b) optionally cooling the pyrolysis vapors to a temperature that is below the pyrolysis temperature; c) contacting the vaporous phase with an aromatization catalyst at an aromatization temperature in the range of 450 - 700 °C, which aromatization temperature is at least 50°C lower than the pyrolysis temperature, in a catalytic conversion step to yield a conversion product comprising aromatic compounds; and d) optionally recovering the aromatic compounds from the conversion product.
LINK
The synthesis of aromatic compounds from biomass-derived furans is a key strategy in the pursuit of a sustainable economy. Within this field, a Diels–Alder/aromatization cascade reaction with chitin-based furans is emerging as a powerful tool for the synthesis of nitrogen-containing aromatics. In this study we present the conversion of chitin-based 3-acetamido-furfural (3A5F) into an array of di- and tri-substituted anilides in good to high yields (62–90%) via a hydrazone mediated Diels–Alder/aromatization sequence. The addition of acetic anhydride expands the dienophile scope and improves yields. Moreover, replacing the typically used dimethyl hydrazone with its pyrrolidine analogue, shortens reaction times and further increases yields. The hydrazone auxiliary is readily converted into either an aldehyde or a nitrile group, thereby providing a plethora of functionalized anilides. The developed procedure was also applied to 3-acetamido-5-acetylfuran (3A5AF) to successfully prepare a phthalimide.
