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Propoxur
Published in Philip H. Howard, Edward M. Michalenko, William F. Jarvis, Dipak K. Basu, Gloria W. Sage, William M. Meylan, Julie A. Beauman, D. Anthony Gray, Handbook of Environmental FATE and EXPOSURE DATA, 2017
Philip H. Howard, Edward M. Michalenko, William F. Jarvis, Dipak K. Basu, Gloria W. Sage, William M. Meylan, Julie A. Beauman, D. Anthony Gray
Summary: Propoxur, known chemically by o-isopropoxyphenyl N-methylcarbamate or 2-(l-methylethoxy)phenol methylcarbamate, is an insecticide and molluscide characterized by a fast knockdown and long residual effect. It will be released to the environment when it is applied as a spray or dust or used in bait to control household pests as well as lawn and garden insects. If released on soil it would not adsorb strongly to the soil, so leaching would be expected. Propoxur is highly persistent in soils. In one field study, 75% of propoxur disappeared from sandy soil in 100 days but levels were virtually unchanged in muck and silt loam soils. However, the rate of biodegradation is markedly increased when the soil has been previously exposed to methylcarbamate pesticides. Additionally, abiotic hydrolysis should be important in alkaline soils. Propoxur is readily degradable in water (half-life from 1 day to 1 week). In surface layers of water it will photolyze relatively rapidly, especially when humic material is present (half-life 13-88 hr). Degradability increases with temperature, high microbial populations, the presence of mud and biota, and increasing pH. Volatilization, adsorption to sediment and bioconcentration in fish should not be important fate processes. Propoxur would be released into the atmosphere primarily as a dust or aerosol and be subject to gravitational settling. The vapor phase chemical should react with photochemically produced hydroxyl radicals and have a half-life of about 4 hr. People will primarily be exposed to propoxur where it is used to control insects, both indoors and outdoors.
Engineered Pseudomonas putida for biosynthesis of catechol from lignin-derived model compounds and biomass hydrolysate
Published in Preparative Biochemistry & Biotechnology, 2022
Catechol and its derivatives are important chemical precursors for several applications such as carbamate insectidices (carbofuran and propoxur), polymerization inhibitors (4-tert-butylcatechol), photographic developers, tanning agents, perfumes, cosmetics, biomaterial and therapeutic agents.[1,2] Annually, 2.5 × 107 kg of catechol is produced commercially by synthetic/chemical routes.[3] The various chemical routes for catechol production include hydrolysis of 2-chloro phenol with copper as a catalyst at elevated temperature; hydroxylation of phenol in presence of peroxide along with catalyst; dehydrogenation of 1,2-cyclohexanediol with palladium as a catalyst at 300 °C; and oxidation of salicylic aldehyde and demethylation of guaiacol.[1,4,5] Chemical synthesis of catechol is a catalyst-based energy intensive process, resulting in the co-production of compounds such as hydroquinone and resorcinol. This compound along with un-reacted phenol mixtures makes separation and scale up a tedious job.[1,6,7] Moreover, catechol is derived from petroleum-based feedstock leading to several environmental issues thereby necessitating focusing our attention toward catechol synthesis from sustainable and renewable starting material using microbes.[3,8] Lignocellulosic biomass is one such sustainable and renewable feedstock giving rise to bio-refinery concept.