Chloroform formation

Purification of drinking water by adding CI2 to kill bacteria is a source of electrophilic chlorine and contributes a nonenzymatic pathway for a chlorina tion and subsequent chloroform formation Al though some of the odor associated with tap water may be due to chloroform more of it probably results from chlorination of algae produced organic com pounds... 

MIMS is a technique that uses a semipermeable membrane for directly introducing analytes into the mass spectrometer. This allows analytes to be measured in realtime with little or no sample preparation. MIMS has been previously used to measure the stability of CNCl in chlorinated and chloraminated drinking water [168], to quantify CNCl and CNBr in drinking water [169], to measure chloramines and chlorobenzenes in water samples [170], and investigate the mechanism and kinetics of chloroform formation in drinking water [171]. More recently, it has been used to measure volatile DBPs in indoor swimming pools [138, 172]. 

Rios RVRA, Da Rocha LL, Vieira TG, Lago RM, Augusti R (2000) On-line monitoring by membrane introduction mass spectrometry of chlorination of organics in water. Mechanistic and kinetic aspects of chloroform formation. J Mass Spectrom 35(5) 618-624... 

Suh DH, Abdel-Rahman MS. 1985. Mechanism of chloroform formation by chlorine and its inhibition by chlorine dioxide. Fundam Appl Toxicol 5 305-313. 

Note that the initial reaction involves the splitting of the hydrogen atom from the methyl group using the hydroxyl ion. The hydroxyl ion is again used in (3), (5), and (7). Because the hydroxyl is involved, this would mean that chloroform formation is enchanced at high pH. To prevent formation of the chloroform, all that is necessary... 

Hrutfiord, B. F., Negri, A. R. Chemistry of chloroform formation in pulp bleaching a review. TappiJ. 1990, 73, 219-225. 

Schall and Gokel have reported the construction of molecular boxes derived from nucleic acid bases and azacrown ethers [23]. Detailed NMR studies provided evidence for the association of A-crown-A with T-crown-T in chloroform. Formation of a ternary receptor complex with a, m-diammonium compounds (Figure 12) was also suggested. 

CUoral, formation of, 71. Chloranilines, formation of, 55. Chloroform, formation of 71. Ohrome yellow, precipitation of, 48. Ohromio acid, regeneration of, 66. Condensation by electrolysis, 72, Current concentration, 86. 

Christman et al. (1978) also chlorinated resorcinol, showing that during chloroform formation it underwent ring contraction to produce the unusual cyclopentene-dione 25. Larson and Rockwell (1979) confirmed Rook s and Christman s observations that resorcinol derivatives were active haloform precursors, and also found that even if the 2-carbon of resorcinol was blocked by a carboxyl group (cf. 26), yields of... 

Rios, R.V.R.A., da Rocha, L.L., Vieira, T.G., Lago, R.M., Augusti, R. (2000) Online Monitoring by Membrane Introduction Mass Spectrometry of Chlorination of Organics in Water. Mechanistic and Kinetic Aspects of Chloroform Formation. J. Mass Spectrom. 35 618-624. 

Composition constancy regardless of the monomer ratio in the reaction mixture allowed to suppose, that copolymerization of DAAH with SO2 proceed via formation of the complexes. Investigations showed simple mixing of the comonomers at 20-80°C to result in momentary formation of a viscous amber-coloured adduct. A new band of a charge transfer with Amax=263 nm (Figure 1) was deteeted in UV-spectra of DAAH and SO2 mixture, recorded in chloroform. Formation of the eomplex of DAAH with SO2, becoming apparent as a result of a deviation from additivity of absorbances of DAAH, SO2 and their mixture (Figure 2), was also detected in DMSO and aqueous solutions. It is seen, that deviation maximum is observed at equimolar ratio of the monomers. 

Some organic compounds can be converted with hexamethyldisilane and iodine (2-3 h at 60°C in chloroform formation of iodotrimethylsilane in situ) into their a-iodo derivatives [600], e.g. 

Ultrafiltration can adequately produce disinfected water directly from strrface water for different applications. MF can also be used for disinfection, although not all viruses are removed. However, direct membrane filtration is limited by fouling, which, during constant-flux filtration, leads to a continuous increase in transmembrane pressure. In addition, UF and MF membrane treatment alone cannot effectively and consistently remove organic material, measured as total organic carbon (TOC), and THM (tri-halo-methane) precursors, measured as chloroform formation potential (Berube et al., 2002). 

---