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Role of Enzymes in the Bioremediation of Refractory Pollutants
Published in Maulin P. Shah, Removal of Refractory Pollutants from Wastewater Treatment Plants, 2021
Viresh R. Thamke, Ashvini U. Chaudhari, Kisan M. Kodam, Jyoti P. Jadhav
Transferase is a class of enzyme that transfers specific functional groups from one molecule (donor) to another (acceptor). This enzyme is also involved in the biodegradation of various industrial wastes. Hydrogen cyanide (HCN) is a major worldwide environmental pollutant produced from the metallurgic industry. HCN contains cyanide which has a strong binding ability to cytochrome oxidase and causes toxicity to aerobic life. Even though it is highly toxic, it can be converted to less toxic forms by an enzyme called rhodanase (thiosulfate: cyanide sulfurtransferases), which is one of the mechanisms employed for cyanide detoxification (Raybuck 1992). Similarly, chloromethane produced in industries has wide use in the production of silicon polymers, the manufacturing of butyl rubber, petroleum refining, etc. Although it has valuable use it is very toxic to the environment and has harmful effects on living systems. An anaerobic acetogenic bacterial strain Acetobacterium dehalogenans isolated from sewage sludge utilizes chloromethane as a sole source of energy (Stanlake and Finn 1982). The aerobic facultative methylotrophic bacteria carry out the degradation of dichloromethane by glutathione-S-transferases to S-chloromethyl glutathione which is an unstable intermediate goes to abiotic hydrolysis to form formaldehyde (Gisi et al. 1998). The cis-dichloroethene and vinyl chloride are the organic pollutants which are degraded by aerobic bacterial monooxygenase resulting in the formation of epoxides which are further degraded by epoxy alkane: coenzyme M transferase (Field and Sierra-Alvarez 2004).
Alkyl Halides and Substitution Reactions
Published in Michael B. Smith, A Q&A Approach to Organic Chemistry, 2020
Formation of chlorine radicals, removal of a hydrogen atom from methane, and reaction of the methyl radical with more chlorine leads to chloromethane and HCl as the products. What is the mechanism for the transformation of 2-methylpropane to 2-chloro-2-methylpropane in the presence of UV light?
Chemicals from Paraffin Hydrocarbons
Published in James G. Speight, Handbook of Petrochemical Processes, 2019
These compounds, known as chloromethane or methyl chloride, dichloromethane or methylene chloride, trichloromethane or chloroform, and tetrachloromethane or carbon tetrachloride, are used as solvents or in the production of chlorinated materials.
Facile and green synthesis of 4,6-dimethoxy-2-methylsulfonylpyrimidine using chloromethane as methylating agent
Published in Journal of the Chinese Institute of Engineers, 2021
Jing Guan, Hang Hu, Bin Wang, Xiangjian Xu, Lele Zhang, Yipeng Xie, Defeng Xu
Chloromethane is a widely used methylating agent in fine chemical production (Milanez 2014). Compared with dimethylsulfate, chloromethane is less toxic. To the best of our knowledge, using chloromethane as methylating agent to synthesize DMSP has not previously been reported. In this work, DMSP was synthesized from 2-thiobarbituric acid by only two steps, as shown in Scheme 1. First, 4,6-dimethoxy-2-methyl-thiopyrimidine was synthesized from 2-thiobarbituric acid using chloromethane instead of dimethylsulfate as methylating agent. Second, 4,6-dimethoxy-2-methylthiopyrimidine was oxidized by hydrogen peroxide to produce the final product DMSP (Xie et al. 2010). 4,6-dimethoxy-2-methylthiopyrimidine was the key intermediate to synthesize DMSP. The reaction conditions for the synthesis of 4,6-dimethoxy-2-methylthiopyrimidine including the alkali species, reaction time, reaction temperature, and the mole ratio of reaction ingredients were screened systematically.
Empirical data in support of a skin notation for methyl chloride
Published in Journal of Occupational and Environmental Hygiene, 2018
Sharyn Gaskin, Leigh Thredgold, Linda Heath, Dino Pisaniello, Michael Logan, Christina Baxter
Methyl chloride (synonym chloromethane) is a colorless gas at room temperature (b.p. −24.2 C) with an estimated odor threshold of 10 ppm. It is typically produced industrially by either the reaction of methanol and hydrogen chloride or via the chlorination of methane.[1] Methyl chloride is used during industrial processes as a methylating and/or blowing agent in the production of silicones, butyl rubber, methylene chloride, plastics, pesticides, pharmaceuticals, dyes, resins, polystyrene, and polyurethane foams.[2] It was also commonly used as a refrigerant in the early to mid-1900s until numerous reported inhalational exposures, resulting from accidental release in both occupational and residential settings, highlighted its human toxicity potential.[3–5] Inhalation of high concentrations of methyl chloride has reportedly led to kidney and liver damage, central nervous system depression, and even death.[1]