Chemistry - A European Journal; 1/26/2021, Vol. 27 Issue 6, p1865-1869, 5p
SUSTAINABLE chemistry, ORGANIC synthesis, CHEMICAL engineering, CHEMICAL processes, INORGANIC chemistry, AMMONIUM sulfate, and METHACRYLATES
Keywords: green chemistry; industrial chemistry; organic synthesis; synthetic methods EN green chemistry industrial chemistry organic synthesis synthetic methods 1865 1869 5 01/29/21 20210126 NES 210126 B Making industry greener b : Many principles for the economic production of organic bulk chemicals, the syntheses of which have potentially the highest environmental impact, currently overlap with principles of green chemistry. For about 93 % of the 250 million tons organic chemicals produced annually by oxidation, oxygen is used as the oxidant, in most cases in combination with catalysts to achieve appropriate selectivities. I Addressed Principles of Green Chemistry: Prevent Waste, Atom Economy, Reduce Derivatives, Catalysis vs. Getting Greener: Propylene Oxide O SB 2 sb is not always the most efficient oxidant, as shown in the different synthetic routes to valuable propylene oxide (Scheme 4). The chlorohydrin process uses chlorine and produces CaCl SB 2 sb as the by-product and is therefore not that green. This would allow the entry into a circular economy.[18, 19] Certain initiatives involving large chemical producers were recently started to introduce a circular economy based on chemcycling in order to replace the current linear use of feedstocks. Greener alternatives should also be as economic as possible. [Extracted from the article]
Science News. July 3, 2010, Vol. 178 Issue 1, p22, 5 p.
Company business management, Biological research -- Methods, Biological research -- Management, Biology, Experimental -- Methods, Biology, Experimental -- Management, Life -- Origin, Life -- Research, and Chemistry, Organic -- Research
A short stroll from Boston's Charles River, behind a sheath of blue glass on the seventh floor of a Harvard Medical School research building, Jack Szostak is getting set to [...]
Freshwater lakes are essential hotspots for the removal of excessive anthropogenic nitrogen (N) loads transported from the land to coastal oceans. The biogeochemical processes responsible for N removal, the corresponding transformation rates and overall removal efficiencies differ between lakes, however, it is unclear what the main controlling factors are. Here, we investigated the factors that moderate the rates of N removal under contrasting trophic states in two lakes located in central Switzerland. In the eutrophic Lake Baldegg and the oligotrophic Lake Sarnen, we specifically examined seasonal sediment porewater chemistry, organic matter sedimentation rates, as well as 33-year of historic water column data. We find that the eutrophic Lake Baldegg, which contributed to the removal of 20 ± 6.6 gN m−2 year−1, effectively removed two-thirds of the total areal N load. In stark contrast, the more oligotrophic Lake Sarnen contributed to 3.2 ± 4.2 gN m−2 year−1, and had removed only one-third of the areal N load. The historic dataset of the eutrophic lake revealed a close linkage between annual loads of dissolved N (DN) and removal rates (NRR = 0.63 × DN load) and a significant correlation of the concentration of bottom water nitrate and removal rates. We further show that the seasonal increase in N removal rates of the eutrophic lake correlated significantly with seasonal oxygen fluxes measured across the water–sediment interface (R2 = 0.75). We suggest that increasing oxygen enhances sediment mineralization and stimulates nitrification, indirectly enhancing denitrification activity. [ABSTRACT FROM AUTHOR]