Sulfur dioxide poisoning

Concentrated sulfuric acid Evolution of carbon monoxide and sulfur dioxide (poisonous)... 

Sulfur dioxide poisoning Upper respiratory tract infections... 

Reduction activity was measured by using the same reactant mix except that oxygen was varied from 0.05 to 0.60% with the temperature held constant at either 482° or 593 °C. Again space velocity was varied by using 1-3 monolithic units. Water-gas shift reaction was studied at 75,000/hr with the reactants being 1% CO, 10% H20, and N2 the balance. For sulfur dioxide poisoning studies, either 50 or 100 ppm sulfur dioxide was added stepwise to the sample at 593°C with the oxygen level maintained at 0.40% the effect on conversion was monitored continuously. 

Rhenium oxides have been studied as catalyst materials in oxidation reactions of sulfur dioxide to sulfur trioxide, sulfite to sulfate, and nitrite to nitrate. There has been no commercial development in this area. These compounds have also been used as catalysts for reductions, but appear not to have exceptional properties. Rhenium sulfide catalysts have been used for hydrogenations of organic compounds, including benzene and styrene, and for dehydrogenation of alcohols to give aldehydes (qv) and ketones (qv). The significant property of these catalyst systems is that they are not poisoned by sulfur compounds. 

Health nd Safety Factors. Thionyl chloride is a reactive acid chloride which can cause severe bums to the skin and eyes and acute respiratory tract injury upon vapor inhalation. The hydrolysis products, ie, hydrogen chloride and sulfur dioxide, are beheved to be the primary irritants. Depending on the extent of inhalation exposure, symptoms can range from coughing to pulmonary edema (182). The LC q (rat, inhalation) is 500 ppm (1 h), the DOT label is Corrosive, Poison, and the OSHA PEL is 1 ppm (183). The safety aspects of lithium batteries (qv) containing thionyl chloride have been reviewed (184,185). 

Shipment and Storage. Liquid sulfur dioxide is commonly shipped in North America using 55- and 90-t tank cars, 20-ton tank tmcks, 1-ton cylinders, and 150-lb cylinders. Cylinders made of specified steel are affixed with the green label for nonflammable gases. The DOT classification is Poison Gas, Inhalation Ha2ard. Purchasers of tank-car quantities are required to have adequate storage faciUties for prompt transfer. 

Vapor Density (VD) — the mass per unit volume of a given vapor/gas relative to that of air. Thus, acetaldehyde with a vapor density of 1.5 is heavier than air and will accumulate in low spots, while acetylene with a vapor density of 0.9 is lighter than air and will rise and disperse. Heavy vapors present a particular hazard because of the way they accumulate if toxic they may poison workers if nontoxic they may displace air and cause suffocation by oxygen deficiency if flammable, once presented with an ignition source, they represent a fire or explosion hazard. Gases heavier than air include carbon dioxide, chlorine, hydrogen sulfide, and sulfur dioxide. 

Use of some biomass feedstocks can increase potential environmental risks. Municipal solid waste can contain toxic materials that can produce dioxins and other poisons in the flue gas, and these should not be burned without special emission controls. Demolition wood can contain lead from paint, other heavy metals, creosote, and halides used in presen a-tive treatments. Sewage sludge has a high amount of sulfur, and sulfur dioxide emission can increase if sewage sludge is used as a feedstock. 

The elements in a compound are not just mixed together. Their atoms are actually joined, or bonded, to one another in a specific way due to a chemical change (see Section A). The result is a substance with chemical and physical properties different from those of the elements that form it. For example, when sulfur is ignited in air, it combines with oxygen from the air to form the compound sulfur dioxide. Solid yellow sulfur and odorless oxygen gas produce a colorless, pungent, and poisonous gas (Fig. C.l). 

Sulfur forms several oxides that in atmospheric chemistry are referred to collectively as SOx (read sox ). The most important oxides and oxoacids of sulfur are the dioxide and trioxide and the corresponding sulfurous and sulfuric acids. Sulfur burns in air to form sulfur dioxide, S02 (11), a colorless, choking, poisonous gas (recall Fig. C.1). About 7 X 1010 kg of sulfur dioxide is produced annually from the decomposition of vegetation and from volcanic emissions. In addition, approximately 1 X 1011 kg of naturally occurring hydrogen sulfide is oxidized each year to the dioxide by atmospheric oxygen ... 

The promotor effect of SO2 increases with the amount added to the reaction medium (Fig.3). An effect of the addition of sulfur dioxide has also been observed on the oxidation of decane with an increase of the activation energy expected for such a poisoning. This addition leads to a noticeable decrease of the rate of oxidation at low temperature, where Cu sulfate is stable, but the effect becomes negligible at about 600 K. At this temperature, the conversion of decane estimated by the evolution of the peak e/m = 57, characteristic of the hydrocarbon, is close to 100% with CufTi02 catalysts in presence or not of SO2 (Figure 4). With Cu/Zr02 SO2 inhibits decane oxidation below 640 K. At 640 K a conversion of about 60% is observed in both the presence or absence of additive and an acceleration of oxidation is noticed at higher temperatures. 

Sulfur dioxide is a colorless, poisonous corrosive gas. It causes coughing and nose, throat and lung irritation, even in small quantities. A primary consequence of releasing S02 into the air is the production of acid rain ... 

Unlike boron fluoride, titanium tetrachloride does not catalyze the liquid phase polymerization of isobutylene under anhydrous conditions (Plesch et al., 83). The addition of titanium tetrachloride to a solution of the olefin in hexane at —80° failed to cause any reaction. Instantaneous polymerization occurred when moist air was added. Oxygen, nitrogen, carbon dioxide, and hydrogen chloride had no promoting effect. Ammonia and sulfur dioxide combined with the catalyst if these were added in small quantity only, subsequent addition of moist air permitted the polymerization to occur. Ethyl alcohol and ethyl ether, on the other hand, prevented the polymerization even on subsequent addition of moist air. They may be regarded as true poisons. 

Other substances decrease or annihilate, even in traces, the catalytic properties of iron. Such catalyst poisons had already been known as a nuisance in the catalytic oxidation of sulfur dioxide. With the ammonia catalysis several elements, particularly sulfur proved to be harmful, even in amounts of 4oo of one per cent. Chlorine, phosphorus and arsenic showed a similar behavior (30), just as certain metals, such as lead, tin and zinc. 

Caution. Because of the poisonous nature of arsenic compounds and sulfur dioxide, all manipulations must be carried out in an efficient fume hood. 100 g (0.505 mol) of As203 are placed in a 500-mL, two-necked, round-bottomed flask, or a one-necked flask fitted with a Claisen head with a dropping funnel, a water-cooled reflux condenser, and a magnetic stirrer... 

NOXIOUS CAS. Any natural or by-product gas or vapor that has specific toxic effects on humans or animals (military poison gases are not included in this group). Examples of noxious gases are ammonia, carbon monoxide, nitrogen oxides, hydrogen sulfide, sulfur dioxide, ozone, fluorine, and vapors evolved by benzene, carbon tetrachloride, and a number of chlorinated hydrocarbons. Oases that act as simple asphyxiants are not classified as noxious. See also Pollution (Air). 

While the fumes from burning mercuric thiocyanate are offensive because of their sulfur dioxide, the small amount of mercury vapor which they contain probably presents no serious danger. The possibility, however, that children may swallow the pellets, with fatal consequences, is a real hazard. For this reason, the sale of mercury snakes has been forbidden by law in many states, and black non-mercury snakes, which are essentially non-poison-ous, have come into general use. 

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