Chloromethane, accounting for approximately 16% of the tropospheric chlorine, is mainly coming from natural sources. However anthropogenic activities, such as combustion of biomass may contribute significantly as well. The present study focuses on the thermal solid state reaction between pectin, an important constituent of biomass, and chloride ions as found in alkali metal chlorides. The formation of chloromethane is evident with the amount formed being linear with respect to chloride if pectin is in great excess. Thus the reaction is explained as a pseudo first order SN2 reaction between the chloride ion and the methyl ester moiety in pectin. It is suggested that the polymeric nature of pectin plays an active role by an enhanced transport of halides along the carbohydrate chain. Optimal reaction temperature is around 210°C. At higher temperatures the yield of chloromethane decreases due to a thermal decomposition of the pectin. The possible influence of the type of cation is discussed.
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http://dx.doi.org/10.1016/j.chemosphere.2014.05.001 | DOI Listing |
J Am Chem Soc
January 2025
School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia.
Designing molecular receptors that bind anions in water is a significant challenge, and an even greater difficulty lies in using these receptors to remove anions from water without resorting to the hazardous liquid-liquid extraction approach. We here demonstrate an effective and synthetically simple strategy toward these goals by exploiting ion-pair assembly of macrocycles. Our anion binding ensemble consists of an octa-chloro tetra-urea macrocyclic anion receptor (ClTU), which forms water-dispersible aggregates, and a tetra-cationic fluorescent dye 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphyrin (TMPyP4), which provides Coulombic stabilization and fluorescence reporting of anion binding in an ion-pair assembly.
View Article and Find Full Text PDFCarbohydr Polym
March 2025
Institute of Chemistry, The Fritz Haber Research Center, and The Harvey M. Krueger Family Center for Nanoscience and Nanotechnology, Edmond J. Safra Campus, The Hebrew University, Jerusalem 9190401, Israel. Electronic address:
Cyclodextrins are widely used pharmaceutical excipients known to increase the solubility of drug compounds through formation of inclusion complexes. A prominent limitation of common cyclodextrins is their own scarce solubility in water, which renders them unsuitable for many drug formulations. Cyclodextrin solubility can be enhanced in appropriate media such as Deep Eutectic Solvents (DESs).
View Article and Find Full Text PDFLangmuir
January 2025
School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin 300350, China.
Ice formation poses a significant challenge across various fields, from industrial processes to biological preservation. Developing antifreeze agents and recognizing the antifreeze mechanism have gained considerable attention. Herein, a series of poly(l-methionine) derivatives, poly(-carboxymethyl-l-methionine sulfonium) (PMetA), poly(-methyl-l-methionine sulfonium chloride) (PMetM), and poly(-carbamidomethyl-l-methionine sulfonium chloride) (PMetAM), with carboxyl, methyl, and acetamide groups, respectively, are synthesized and investigated for antifreeze.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen, 40002, Thailand.
Celosia argentea is a plant known for producing bioactive compounds, including betalains, which possess various biological and pharmaceutical properties. This study aimed to investigate the effect of biotic and abiotic elicitors on betalains production and their antioxidant activity in cell suspension cultures of C. argentea.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, Massachusetts 01003-9303, United States.
Polymeric membranes fabricated via the nonsolvent-induced phase separation process rely heavily on toxic aprotic organic solvents, like -methyl-pyrrolidine (NMP) and dimethylformamide. We suggest that the "saloplastic" nature of polyelectrolyte complexes (PECs) makes them an excellent candidate for fabricating next-generation water purification membranes that use a more sustainable aqueous phase separation process. In this study, we investigate how the properties of PECs and their interactions with salt can form pore-containing membranes from the strong polyelectrolytes poly(sodium 4-styrenesulfonate) (PSS) and poly(diallyldimethylammonium chloride) (PDADMAC) in the presence of potassium bromide (KBr).
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