Methyl toxicity

Folic acid, 4-amino-4-deoxy-10-methyl-, 1, 164 3, 325 as anticancer drug, 1, 263 biological activity, 3, 325 Folic acid, 4-amino-10-methyl-toxicity, 1, 141 Folic acid, 7,8-dihydro-biosynthesis, 3, 320 synthesis, 1, 161, 3, 307 Folic acid, 4-dimethylamino-hydrolysis, 3, 294 Folic acid, 5-formiminotetrahydro-biological activity, 3, 325 Folic acid, 5-formyl-5,6,7,8-tetrahydro-biological activity, 3, 325 chirality, 3, 281 occurrence, 3, 325 Folic acid, 10-forfnyltetrahydro-biological activity, 3, 325 Folic acid, 5,10-methenyl-5,6,7,8-tetrahydro-biological activity, 3, 325 chirality, 3, 281 Folic acid, 5-methyl-chirality, 3, 281 Folic acid, 9-methyl-toxicity, 1, 141... 

Methylation Toxic methylating agents (dimethyl sulphate, methyl iodide, methyl... 

Hg° (used in industrial Toxic vapor (neuro- Abiotic oxidation Hg2+ and methyl Toxic compounds, nephro-... 

Experiments involving the use of dimethyl sulphate should be carried out by students only under immediate supervision. Not only is the vapour of dimethyl sulphate highly poisonousy but the cold liquid itself is absorbed easily through the skin, with toxic results individual susceptibility to ditnethyl sulphate poisoning varies and may be very high. If the sulphate is splashed on to the hands, wash immediately with plenty of concentrated ammonia solution in order to hydrolyse the methyl sulphate before it can be absorbed through the skin (see p. 528). 

Nitrobenzene (and many other liquid organic compoimds containing nitrogen) is appreciably toxic and its vapour should not be allowed to escape into the atmosphere of the laboratory the delivery tube of the condenser should pass well into the mouth of the receiver flask. The liquid is also a skin poison if it Is accidentally spilled on the skin, it should be removed by washing with a litt e methylated spirit, followed by soap and warm water. 

Table 4 lists a variety of aLkoxypropionaldehydes and certain of thek properties (67). Alcohols up to -butyl have been added to acroleki ki this fashion. Methyl, ethyl, and aHyl alcohols react with ease, while the addition of hexyl or octyl alcohol proceeds ki low yields. Although the aLkoxypropionaldehydes have found only limited kidustrial utiUty, it is anticipated that they will find use as replacements for more toxic solvents. Furthermore, the aLkoxypropionaldehydes may readily be reduced to the corresponding alkoxypropanols, which may also have deskable properties as solvents. 

There are three types of TAP emissions continuous, intermittent, and accidental. Both routine emissions associated with a batch process or a continuous process that is operated only occasionally can be intermittent sources. A dramatic example of an accidental emission was the release of methyl isocyanate [624-83-9] in Bhopal, India. As a result of this accident, the U.S. Congress created Tide III, a free-standing statute included in the Superfund Amendments and Reauthorization Act (SARA) of 1986. Title III provides a mechanism by which the pubHc can be informed of the existence, quantities, and releases of toxic substances, and requires the states to develop plans to respond to accidental releases of these substances. Eurther, it requires anyone releasing specific toxic chemicals above a certain threshold amount to aimuaHy submit a toxic chemical release form to EPA. At present, there are 308 specific chemicals subject to Title III regulation (37). 

Codeiae (2, R = CH3) occurs ia the opium poppy along with morphine (2, R = H) but usually ia much lower concentration. Because it is less toxic than morphine and because its side effects (including depression, etc) are less marked, it has found widespread use ia the treatment of minor pain and much of the morphine found ia cmde opium is converted to codeiae. The commercial coaversioa of morphine to codeiae makes use of a variety of methylating ageats, amoag which the most common are trimethylphenylammonium salts. Ia excess of two huadred toas of codeiae are coasumed anauaHy from productioa faciUties scattered arouad the world. 

CeUulose triacetate is insoluble in acetone, and other solvent systems are used for dry extmsion, such as chlorinated hydrocarbons (eg, methylene chloride), methyl acetate, acetic acid, dimethylformamide, and dimethyl sulfoxide. Methylene chloride containing 5—15% methanol or ethanol is most often employed. Concerns with the oral toxicity of methylene chloride have led to the recent termination of the only triacetate fiber preparation faciHty in the United States, although manufacture stiH exists elsewhere in the world (49). 

Emulsives are solutions of toxicant in water-immiscible organic solvents, commonly at 15 ndash 50%, with a few percent of surface-active agent to promote emulsification, wetting, and spreading. The choice of solvent is predicated upon solvency, safety to plants and animals, volatility, flammabiUty, compatibihty, odor, and cost. The most commonly used solvents are kerosene, xylenes and related petroleum fractions, methyl isobutyl ketone, and amyl acetate. Water emulsion sprays from such emulsive concentrates are widely used in plant protection and for household insect control. 

Health and Safety Factors. MEK is slightly more toxic than acetone, but is not considered highly toxic, and nor does it exhibit cumulative toxicological properties. The OSHA time weighted average iu air is 200 ppm other measured toxicity values are shown iu Table 3. Methyl ethyl ketone is highly flammable. 

Methyl vinyl ketone is used as a comonomer in photodegradable plastics, and is an intermediate in the synthesis of steroids and vitamin A. It is highly toxic and faciUties handling over a threshold of 100 lbs (45.5 kg) are subject to special OSHA documentation regulations (273). 

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