Sulfur dioxide vapor pressure

Sulfur Dioxide Vapor Pressure and pH of Sodium Citrate Buffer Solutions with Dissolved Sulfur Dioxide... 

Potassium fluorosulfite is a colorless crystalline powder which, because of hydrolysis, smells of sulfur dioxide and which must necessarily be stored under protection from moisture. The following relationship applies for the sulfur dioxide vapor pressure over potassium fluorosulfite ... 

Reaction of myrcene and sulfur dioxide under pressure produces myrcene sulfone. This adduct is stable under ordinary temperatures and provides a way to stabilize the conjugated diene system in order to hydrate it with sulfuric acid. The myrcene sulfone hydrate produced is pyrolyzed in the vapor phase in order to regenerate the diene system to produce myrcenol [543-39-5] (50). 

Another approach is to react myrcene with sulfur dioxide under pressure to give myrcene sulphone (69). This can then be hydrated using sulfuric and the sulfur dioxide removed from the intermediate (70) by vapor-phase pyrolysis to produce myrcenol [543-39-5] (71). The sulfur dioxide can be recovered and recycled and the myrcenol purified by distillation. Diels-Alder addition of this with acrolein then produces Lyral [69, 86]. This synthetic sequence is shown in Fig. 8.16. 

Reaction in the presence of water vapor was found to proceed at a rate independent of oxygen partial pressure and proportional to sulfur dioxide partial pressure. Furthermore, the rate was found to be proportional to the fraction of Na20 unreacted, in line with Bartlett s findings on alunite and the mathematical model [113] mentioned previously. This proportionality between the rate of reaction and the fraction of Na20 unreacted (1 — be deduced from the straight line observed when the fraction unreacted is plotted against time on a semilogarithmic scale as shown in Fig. 8.18. 

Physical Properties. Sulfur dioxide [7446-09-5] SO2, is a colorless gas with a characteristic pungent, choking odor. Its physical and thermodynamic properties ate Hsted in Table 8. Heat capacity, vapor pressure, heat of vaporization, density, surface tension, viscosity, thermal conductivity, heat of formation, and free energy of formation as functions of temperature ate available (213), as is a detailed discussion of the sulfur dioxide—water system (215). 

Fig. 1. Flow diagram of production of sulfur dioxide from oleum 1, 30% oleum exchanger 2, SO vaporizer 3, reactor 4, coolant surge tank 5, coolant ckculatkig pump 6, coolant exchangers 7, sludge and acid pump 8, scmbber 9, SO2 cooler 10, gas cleaner 11, SO2 compressor 12, pulsation damper and 13, SO2 condenser. CM is the condensate FRC, flow recording controller PIC, pressure kidicatkig controller SM, steam TC, temperature recorder ...

Zirconium is a highly active metal which, like aluminum, seems quite passive because of its stable, cohesive, protective oxide film which is always present in air or water. Massive zirconium does not bum in air, but oxidizes rapidly above 600°C in air. Clean zirconium plate ignites spontaneously in oxygen of ca 2 MPa (300 psi) the autoignition pressure drops as the metal thickness decreases. Zirconium powder ignites quite easily. Powder (<44 fim or—325 mesh) prepared in an inert atmosphere by the hydride—dehydride process ignites spontaneously upon contact with air unless its surface has been conditioned, ie, preoxidized by slow addition of air to the inert atmosphere. Heated zirconium is readily oxidized by carbon dioxide, sulfur dioxide, or water vapor. 

TABLE 2-144 Partial Vapor Pressure of Sulfur Dioxide over Water, mm Hg... 

In a i-l. three-necked flask are mixed 150 g. (r.63 moles) of /3-hydroxyethyl methyl sulfide (p. 54) (Note i) and 200 g. of dry chloroform (Note 2). The flask is placed on a steam bath and is fitted with a dropping funnel, a mechanical stirrer, and a condenser. The condenser is fitted with a trap to remove the vapors of hydrogen chloride and sulfur dioxide (page 2). A solution of 204 g. (1.7 moles) (Note 3) of thionyl chloride in 200 g. (135 cc.) of dry chloroform is added dropwise to the /3-hydroxyethyl methyl sulfide over a period of about two hours (Note 4). The reaction mixture is stirred vigorously during this addition and for about four hours after the addition is complete. The chloroform is distilled on the steam bath and the residue is distilled under reduced pressure. The yield is 135-153 g- (75 5 per cent of the theoretical amount) of a product boiling at 55-s6°/3o mm- (Note 5). 

A mixture of sulfur dioxide and sulfur vapor is passed through an electrical discharge at 120 °C and a total pressure of 0.5-0.9 mbar (50-90 Pa). Behind the discharge the gas is allowed to react with an excess of elemental sulfur to increase the S2O content which reaches 86% at most [11] ... 

Sodium hydrosulfite is produced through the Formate process where sodium formate solution, sodium hydroxide, and liquid sulfur dioxide reacted in the presence of a recycled stream of methanol solvent. Other products are sodium sulfite, sodium bicarbonate, and carbon monoxide. In the reactor, sodium hydrosulfite is precipitated to form a slurry of sodium hydrosulfite in the solution of methanol, methyl formate, and other coproducts. The mixture is sent to a pressurized filter system to recover sodium hydrosulfite crystals that are dried in a steam-heated rotary drier before being packaged. Heat supply in this process is highly monitored in order not to decompose sodium hydrosulfite to sulfite. Purging is periodically carried out on the recycle stream, particularly those involving methanol, to avoid excessive buildup of impurities. Also, vaporized methanol from the drying process and liquors from the filtration process are recycled to the solvent recovery system to improve the efficiency of the plant. 

The disadvantages of sulfur dioxide are its high vapor pressure and its low solvent power under normal operating conditions. Fortification of sulfur dioxide with benzene to increase solvent power has been successful in some applications (4). On the other hand, the high volatility of sulfur dioxide results in easy solvent stripping, and its low viscosity aids rapid settling. 

The liquid sulfur dioxide solutions described in the preparations have a vapor pressure of about 3.3 atm at 21 °C. Therefore, well-constructed glass vessels and a glass (or metal) vacuum line must be employed to prevent pressure bursts. Thick leather gloves, safety goggles, a face shield, and a rubber apron should be worn and the experiments have to be conducted behind a safety shield or explosion-proof glass in a fume hood to prevent possible contact with the reaction mixtures as well as with AsF5 and SbFs. 

Every mineral is a product of the redistribution or recombination of its component chemical elements to form a stable substance. The process is known as crystal I izution. The process may involve precipitation of chemical elements from aqueous solutions at the earth s surface, ui from siliceous melts imagmas) from the earth s interior. In either situation, the process is dependent upon the degree of concentration of the constituent chemical elements present and the temperaturc/pressure conditions. Preeipilalion from vapor also is possible. An example is the hot vapor, rich in sulfur dioxide, which is emitted from vents associated with volcanoes. Upon becoming exposed to Ihe cooler atmosphere, crystal sulfur is deposited around those vents. Snow crystals arc another example of precipitation from vapor. 

A mixture of sulfur dioxide. S02. and sulfur vapor, at low pressure and with an electric discharge, forms sulfnr monoxide, SO Its presence is shown from its absorption spectrum, but upon separation it dispropor-tionates at once to sulfur and S02. Sulfur sesquioxide. S2Ojt, is formed by reaction of powdered sulfur with anhydrous SO3 S20 also dispropor-tionates (at 20°C in nitrogen) to sulfur and S02, Sulfur dioxide, S02, is... 

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