Dichloromethane regulations

So acrylic acid would bear R25 (LD50 o-n 34 mg/kg) R22 (LD50 o-r 235 340 353 355) or no code (LD50 o-r 2590). Benzene, toluene, 1-propanol, dichloromethane, etc., can be either R22 or have no code by ingestion depending on the values (labour regulations actually chose not to allocate any acute toxicity code to them). 

Extractions and Chemical Analyses of Amaranthus palmerl S. Wats (Amaranthaceae). The plant material for the chemical studies was supplied by Dr. R. M. Menges, USDA, Weslaco, TX. The air-dried aerial parts (518 g) were extracted at ambient temperature with petroleum ether (PE), dichloromethane (CI Clj) and methanol (MeOH) and the solvents were evaporated In vacuo providing 4.5 g, 4.7 g and 12.lg crude extracts, respectively. Samples of the crude extracts were tested by Dr. J. M. Bradow for germination regulation activity and the biological data are described in her paper. 

Because of the low detection limit requirements, a concentration factor from the usual 1 litre of sample of between 1000- and 10 000-fold is required. This is usually achieved by solvent extraction, followed by evaporation of the extract to a small volume. However, the introduction of the Control Of Substances Hazardous to Health Regulation, 1989 (COSHH) has caused concern about the relatively large volumes of solvent used for extraction—especially chlorinated solvents such as dichloromethane. In order to reduce the volume of solvent used, solid phase extraction, using commercially available C 3 bonded-phase cartridges, is being introduced. 

United States Food and Drug Administration (1996) Dichloromethane. US Code Fed. Regul., Title 21, Part 173.255, p. 116... 

David RM, Clewell HJ, Gentry PR, Covington TR, Morgott DA, Marino DJ. 2006. Revised assessment of cancer risk to dichloromethane. II. Application of probabilistic methods to cancer risk determinations. Regul Toxicol Pharmacol 45 55-65. 

Pelekis M, Krishnan K. 1997. Assessing the relevance of rodent data on chemical interactions for health risk assessment purposes a case study with dichloromethane-toluene mixture. Regul Toxicol Pharmacol 25 79-86. 

The following are examples of priority pollutants arsenic, selenium, barium, cadmium, chromium, lead, mercury, silver, benzene, ethylbenzene, chlorobenzene, chloroethene, dichloromethane, and tetrachloroethene. The priority pollutants also include the pesticide and fumigant eldrin, the pesticide lindane, the insecticide methoxychlor, the insecticide and fumigant toxaphene, and the herbicide and plant growth regulator silvex. There are a total of 65 priority pollutants. 

In the case of expanded porphyrins, the transport-based approach, which is relevant to potential applications involving the regulation of anion flux (e.g., the development of chloride anion carriers for treatment of cystic fibrosis or adjuvants to allow improved uptake into cells of antiviral agents), has for the most part involved the use of a U-tube aqueous I-dichloromethane-... 

Marino, D. J., Clewell, H. J., Gentry, P. R., Covington, T. R., Hack, C. E., David, R. M., and Morgott, D. A. (2006). Revised assessment of cancer risk to dichloromethane Part I Bayesian PBPK and dose-response modeling in mice. Regul Toxicol Pharmacol 45, 44-54. 

Marino, D. J., and Starr, T. B. (2007). Probabilistic dose-response modeling Case study using dichloromethane PBPK model results. Regul Toxicol Pharmacol 49, 285-300. 

By regulating the quantity of sulfuryl chloride, it is possible, in the chlorination of methane, to obtain a yield of 50 per cent chloroform. When a lesser quantity of sulfuryl chloride is used, it is obvious that a larger proportion of mono- and dichloromethanes is formed. The reaction is promoted by the presence of ionizing agents such as light, heat, metallic chlorides, and activated carbon. The heat of reaction is slightly greater... 

It is important to remember that all these tests should be preceded by an appropriate risk assessment in order to implement all the reasonable health and. safely measures. For instance the use of such toxic chemicals as dichloromethane is the subject of COSHH (Control of Substances Hazardous to Health) regulation. Other activities where latent energy is involved, as in the application of hydrostatic pressure, and scattering of specimen debris from a fracture test, also pose a degree of hazard. Obviously the full circumstances are best known to the actual people engaged in any specific work, and therefore they are best placed to conduct a risk assessment and establish appropriate health and safety measures practices. 

Methylene Chloride (Dichloromethane). Methylene chloride is not flammable. Unlike other members of the class of chlorocarbons, it is not currently considered a serious carcinogenic hazard. Recently, however, it has been the subject of much serious investigation, and there have been proposals to regulate it in industrial situations in which workers have high levels of exposure on a day-to-day basis. Methylene chloride is less toxic than chloroform and carbon tetrachloride. It can cause liver damage when ingested, however, and its vapors may cause drowsiness or nausea. 

Fig. 12.2 Apparatus for the photooxygenation in flow. (A) Reservoir for the soluutm of dihydroartemisic acid and the sensitizer (tetraphenylporphyrin) in dichloromethane, (B) HPLC pump, (C) mass-flow controller to control the oxygen flow, (D) manometer, (E) oxygen tank. (F) Check valve, (G) ethylene-tetrafluoroethylene T mixer, (H) fluorinated ethylenepropylene copolymer tubing, (I) quartz immersion well connected to a cooling system, (J) Pyrex filter, (K) connection to the medium-pressure mercury arc (450 W), (L) reservoir for the trifluoroacetic acid solution, (M) acid-resistant HPLC pump, (N) polytetrafluoroethylene thermal reactor, (O) back pressure regulator, (P) collection flask. The two solutions are mixed at a flow rate of 2.5 mL min with a stream of oxygen gas (7.5 mL min ). The residence time in the reactor is ca. 2 min. Reprinted with permission from [32]...

Finally, it is important to remember that the catalogue of solvents is not immutable. Different solvents naturally fall in and out of favour, depending on environmental regulations and tbe types of chemistry being performed at a given time. Data from GSK suggests that toluene, dichloromethane (DCM)... 

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