Chlorates toxicity

Because small children may suck on matches, the question of toxicity is often raised and the lingering, vague, though unwarranted idea of phosphoms poisoning may cause concern to laymen and even to physicians. Potassium chlorate is the only active material that can be extracted in more than traces from a match head and only 9 mg are contained in one head. This, even multiphed by the content of a whole book, is far below any toxic amount (19) for even a small child. No poisonous properties whatsoever can be imputed to the striking strip. SAW matches are similarly harmless but, because of their easy flammabihty, they should be entirely kept out of a household with smaller children. The same warning may apply to all wooden matches. 

Dusts associated with these oxidising compounds produce caustic irritation of skin, eyes, and nasal membranes. Appropriate protection should be worn when handling. Skin contact should be treated as for any caustic material, ie, flush with water and neutralize. Toxicity is low to moderate and is the same as for the hydroxides. Toxicity of the chlorate is greater than for the peroxides and superoxides, and the chlorate material also causes local irritation. 

One of the most widespread methods of water disinfection is it s chlorination. As chloration products ai e toxic, their content is to be controlled. Among them free chlorine and inorganic chloramines ai e predominant in water. Maximum contaminant limit for free chlorine is 0.3 - 0.5 mg/L, for chloramines - 0.8 - 1.2 mg/L. 

This is the reaction by which sodium chlorate is manufactured commercially. In the present context, however, the formation of chlorates is generally undesirable since they tend to be explosive and toxic. The reaction given by Equation 26.2 is strongly affected by pH and temperature as well as the hypochlorite ion concentration. As the alkali becomes exhausted, and the system is thus over-chlorinated, the rate of chlorate formation is greatly accelerated as the reaction becomes auto-catalysed by hypo-chlorous acid. The acid is formed by... 

Chlorates Compounds formed from chloric acid(HC103), by combination of the monovalent radical -C103 a metal, hydrogen or other radical, are called chlorates. The chlorate salts are crystalline some are deliquescent they are decompd by heat with evolution of oxygen sol ih water and are powerful oxidg agents. The principal toxic effects are the production of methemoglobin in the blood destruction of red blood corpuscles... 

Qf -93.5kcal/mol Heat Capacity 23.96 cal/deg/mol at 298°K sol in w, alkalies or aq KC1 si sol in glycerol or ethyleneglycol nearly insol in abs ale or abs acet. Potassium chlorate is si to moderately poisonous the principal toxic effects are the production of methemoglobin and the destruction of red blood corpuscles. The probable lethal dose is 50-500mg/kg or betw one teaspoonful and one ounce for a 150-lb man... 

Since Os04 is volatile, toxic and expensive, considerable effort has been devoted to the catalytic application of the cis dihydroxylation of alkenes in the presence of excess cooxidant.57-290 Previous procedures used metal chlorate (Hoffman reagent),339 or hydrogen peroxide (Milas reagent)350 as cooxidant, usually in Bu OH or acetone.290 Recent procedures utilize t-butyl hydroperoxide in conjunction with ammonium salts (Et4NOH or Et4NOAc)57,351 or N-methylmorpholine N-oxide,352 and are generally more selective. 

Sb trisulfide has an intraperitonal lethal dose in rats of 1.0g/kg (Ref 9) and a (human) toxic tolerance of 0.5mg/cm of air (Ref 10). According to Sax (Ref 7) the sulfide presents a dangerous hazard when heated to decompn or in contact with acids or acid fumes, as it emits highly toxic fumes of the oxides of S or Sb. When the sulfide is reacted with w or steam it produces toxic and flammable vapors, and in contact with strong oxidizing matls it reacts in a vigorous exothermic manner. It can also spontaneously react with chlorates and perchlorates with a moderate risk of expin... 

In addition, NR is a very convenient genetic marker, that has the potential to be selected or counter-selected in many organisms, whether they be plants (Caboche Rouze, 1990 Nussaume et al., 1991) or microorganisms (Unkles et al., 1989). NR-deficient (NR-) mutants will not grow on nitrate, but unlike wild-type organisms will not be killed by chlorate, a nitrate analogue that is toxic when reduced by NR. 

Chlorine dioxide breaks down to leave the inorganic chemicals chlorite and chlorate. These are best managed by controlling the dose of chlorine dioxide applied to the water. Chlorate can also be found in hypochlorite solution that has been allowed to age. There is no guideline value for chlorate because of limited data on its toxicology, but this chemical has been shown to be less toxic than chlorite and is present at lower concentrations. Controlling chlorite will generally also adequately control chlorate. 

Sodium and potassium chlorates are popular weedkillers which are highly toxic after oral ingestion. Cyanosis and methaemoglobinaemia are common features of poisoning with these substances. A test for oxidising agents in stomach contents is given on p. 5. 

From the mechanism shown in Scheme 7.23, we would expect the dihydroxylation with syn-selectivity. The cyclic intermediate may be isolated in the osmium reaction, which is formed by the cycloaddition of OSO4 to the alkene. Since osmium tetroxide is highly toxic and very expensive, the reaction is performed using a catalytic amount of osmium tetroxide and an oxidizing agent such as TBHP, sodium chlorate, potassium ferricyanide or NMO, which regenerates osmium tetroxide. For example, Upjohn dihydroxylation allows the syn-selective preparation of 1,2-diols from alkenes by the use of catalytic amount of OSO4 and a stoichiometric amount of an oxidant such as NMO. 

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