Search

A new method for the direct synthesis of ?-chloro-N?- tosylamidines from olefins using chloramine-T and trifluoromethanesulfonic acid is described. � Georg Thieme Verlag Stuttgart - New York.

Distribution system monitoring programs typically do not include viral indicators. Coliphages are bacterial viruses that infect Escherichia coli and are used as indicators for human enteric viruses. A study of the Iowa-American Water Company distribution system in Davenport, Iowa, attempted to demonstrate the benefit of coliphage monitoring and suggested that these organisms may be effective indicators of distribution system integrity for contamination resulting from main breaks. Coliphages are particularly well-suited for detecting viral intrusion in chloraminated systems because of their resistance to chloramines.

A switch from free chlorine to chloramine disinfectant triggered problems with excessive lead in Washington, D.C., drinking water. High levels of lead originated in the service lines, but excessive lead was also derived from solder or brass plumbing materials. In many cases, the highest lead concentrations emerged from the tap after about 1 min of flushing-a troublesome outcome, given that routine public notification recommended that consumers flush for about a minute to minimize lead exposure. Bench-scale testing found that chlorine reacts with soluble Pb +2 to rapidly precipitate a red-brown-colored lead solid that was insoluble even at pH 1.9 for 12 weeks; this solid did not form in the presence of chloramine. Further experiments indicated that chloramines sometimes dramatically worsened lead leaching from brass relative to free chlorine, whereas new lead pipe was not strongly affected.

Bench-scale experiments determined the inactivation rates of adenovirus serotype 2 with low-pressure, high-output ultraviolet (UV) light, chlorine (Cl 2 ), and preformed chloramines. Studies with sequential chloramines were also done to mimic water treatment practices. Sequential experiments with adenovirus serotype 2 suspended in laboratory-grade water and natural waters containing ammonia were exposed to either UV light followed by Cl 2 /chloramines or the reverse sequence. Adenovirus log reductions were quantified through cell culture techniques. A free Cl 2 C × T (concentration x time) of 1.22 mg-min/L resulted in a 3.72-log reduction, a preformed chloramine C x T of 264.5 mg-min/L resulted in a 1.2-log reduction, a sequential chloramine C x Tof 40.5 mg-min/L resulted in a 1-log reduction, and a UV dose of 40 mJ/cm 2 resulted in a 1-log reduction. Up to 4-log reductions were achieved with a UV dose of 40 mJ/cm 2 followed by a sequential chloramine C × T of 27.2 mg-min/L. This suggests that sequential disinfection may be the best option for dealing with UV-resistant organisms such as adenoviruses.

T ... ma Bra bewlicial for control of Legionella in plumbing9MM"s major appeal. Because monochloramine chlorine penetrates biofilms better than free chlorine, the hypothesis that chloramines are more effective in the biological niche of Legionella is biologically plausible. Investigators from the Centers for Disease Control and Prevention (CDC) presented a study in the September 2000 issue of Journal AWWA concluding that the use of monochloramine for disinfection of municipal water might prevent Legionnaires' disease.1 These authors suggested that 90 percent of hospital-acquired outbreaks of Legionnaires' disease associated with drinking water might not have occurred if monochloramine had been used instead of free chlorine for residual disinfection.1

For producing antibacterial textiles, the conventional finishing processes have high productivity and low processing costs, but textiles finished in these ways exhibit low durability against laundering. Therefore, cotton fabrics were bleached with hydrogen peroxide, finished with triclosan, and then treated with polycarboxylic acids such as 1,2,3,4-butanetetracarboxylic acid (BTCA) and citric acid (CA) as crosslinking agents to provide durable antibacterial properties. The surface of fibers treated with BTCA had a greater crosslinked area, and the surfaces of fabrics treated with CA were exposed to greater amounts of deformation due to the mechanical and chemical influences after 50 launderings. The bleaching and finishing treatments did not dramatically affect the breaking strength. However, the polycarboxylic acid treatment (both BTCA and CA) alone showed reductions in the breaking strength when the acid concentration was increased. The polycarboxylic acids were fairly effective against both bacteria, even at lower concentrations, when they were applied to stand-alone cotton fabrics, whereas the antibacterial activity decreased somewhat after the use of polycarboxylic acid and triclosan in the same recipes. Adding polycarboxylic acids to the antibacterial finishing recipes enhanced the durability after 50 launderings, and the durability of the recipes containing BTCA was much higher than that of the recipes containing CA. (c) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 1.3441352, 2009

Environmentally benign HPA is found to be an efficient catalyst for aziridination of olefins in the presence of inexpensive Chloramine-T as a nitrogen source: instantaneous at room temperature, requires only stoichiometric amount of olefin and no allyl amine side product.

The kinetics of chlorine isotope exchange between chloramine-B /CAB/ and chloride has been studied using ion-exchange separation and tracer technique. McKay's plot are linear. The exchange reaction is fast in acidic medium, very slow in neutral medium and does not take place in alkaline medium. In the acidic range the exchange is maximum at pH 3.3. The rate of exchange decreases at pH >3.3 and 5. Addition of neutral salt or parent compound has no effect on the rate of exchange. Activation energy and activation entropy for this exchange reaction have been calculated. ? 1989 Akad�miai Kiad�.

Hydrogen sulphide at trace level can be determined by radiorelease technique using radiochloramine-T. The minimum detection level is 0.25 ppm. Zinc acetate is used to fix H2S from air samples. CS2 does not interfere. Interference by SO2 can be eliminated by oxidizing it with H2O2. ? 1989 Akad�miai Kiad�.