Liquid SO2

Because of its low dielectric constant, Hquid hydrogen sulfide is a poor solvent for ionic salts, eg, NaCl, but it does dissolve appreciable quantities of anhydrous AlCl, ZnCl2, FeCl, PCl, SiCl, and SO2. Liquid hydrogen sulfide or hydrogen sulfide-containing gases under pressure dissolve sulfur. At equihbrium H2S pressure, the solubihty of sulfur in Hquid H2S at —45, 0, and 40°C is 0.261, 0.566, and 0.920 wt %, respectively (98). The equiHbria among H2S, H2S, and sulfur have been studied (99,100). 

Shale samples were also treated with gaseous SO2 > liquid CO2, liquid NH3, water, and several organic liquids at 25°C for 2 days. Procedures equivalent to those used with liquid SO2 were... 

Shale samples were subjected to treatment with other fluids at 25°C to provide comparative data on their ability to fracture these shales. From among these fluids only gaseous SO2, liquid NH3, and methylene chloride were effective fracturing agents under these conditions. The results are summarized in Table II. Under the same conditions of temperature and pressure, gaseous SO2 is less effective than the liquid in producing fractures. 

Both liquid NH3 and methylene chloride produce roughly the same degree of fracturing as liquid SO2. Liquid NH3, however, appears to produce the greatest fracturing with Antrim shale and the... 

Figure 11-57. Dependence of the radiation yield of SO2 liquid-phase oxidation on the current density and acidity.

Scrubbed Boiler Fluegas 120 49 E E 15% CO2.3% O2, less than 100 ppm SO2- Liquid spray with some dissolved solids present, pH 6 7. Scrubbing of SO2 and fly ash from power plant flue gas. Aeration — moderate Agitation — by gas flow Total days — 158... 

Sulphur monochloride, S2CI2, m.p. —80 C, b.p. I38"C. Yellow liquid hydrolysed by water to SO2, HCl and S. Lower halides S CIj (jt up to 5) are formed S2CI2 plus H2 at a hot surface with freezing of products. S2CI2 is used in the rubber industry as a solvent for S. 

Batch Stirred Tank SO Sulfonation Processes. If the color of the derived sulfonate is not critical, such as ia the productioa of oil-soluble ag-emulsifiers, a simple batch sulfoaatioa procedure can be employed based on vaporizing liquid SO (Niaol Labs, 1952) (13,263). Pilot Chemical Company adapted the original Morrisroe 60—70% oleum—SO2 solvent sulfonation process (256) to utilize 92% Hquid SO —8% Hquid SO2 mixtures, and more recently usiag 100% Hquid SO. This cold sulfoaatioa low viscosity sulfoaatioa process produces exceUeat quaHty products, and reportedly has also been adapted for continuous processiag as weU. The derived sulfonic acid must be stripped of SO2 solvent after completing sulfonation and digestion. 

Liquid Cathode Cells. Liquid cathode cells were discovered at almost the same time as the successful soHd cathode cells. A strongly oxidising hquid such as SO2, was deterrnined to be suitable for direct contact with the strongly reducing lithium, because an excellent passivating film forms... 

Gas-Film Coefficient Since the gas film is not affected by the liquid-phase reaction, one of the many available correlations for physic absorption may be apphcable. The coefficient also may be found directly after elimination of the hquid-film coefficient by employing a solution that reacts instantaneously and irreversibly with the dissolved gas, thus cancehng out any backpressure. Examples of such systems are SO2 in NaOH and NH3 in H2SO4. 

The reaction of metals with gas mixtures such as CO/CO2 and SO2/O2 can lead to products in which the reaction of the oxygen potential in the gas mixture to form tire metal oxides is accompanied by the formation of carbon solutions or carbides in tire hrst case, and sulphide or sulphates in the second mixture. Since the most importairt aspects of this subject relate to tire performairce of materials in high temperature service, tire reactions are refeiTed to as hot corrosion reactions. These reactions frequendy result in the formation of a liquid as an intermediate phase, but are included here because dre solid products are usually rate-determining in dre coiTosion reactions. 

The secondary source of fine particles in the atmosphere is gas-to-particle conversion processes, considered to be the more important source of particles contributing to atmospheric haze. In gas-to-particle conversion, gaseous molecules become transformed to liquid or solid particles. This phase transformation can occur by three processes absortion, nucleation, and condensation. Absorption is the process by which a gas goes into solution in a liquid phase. Absorption of a specific gas is dependent on the solubility of the gas in a particular liquid, e.g., SO2 in liquid H2O droplets. Nucleation and condensation are terms associated with aerosol dynamics. 

Finally, atmospheric chemical transformations are classified in terms of whether they occur as a gas (homogeneous), on a surface, or in a liquid droplet (heterogeneous). An example of the last is the oxidation of dissolved sulfur dioxide in a liquid droplet. Thus, chemical transformations can occur in the gas phase, forming secondary products such as NO2 and O3 in the liquid phase, such as SO2 oxidation in liquid droplets or water films and as gas-to-particle conversion, in which the oxidized product condenses to form an aerosol. 

One example is sampling for S02- Liquid sorbents for SO2 depend on the solubility of SO2 in the liquid collection medium. Certain liquids at the correct pH are capable of removing ambient concentrations of SO2 with 100% efficiency until the characteristics of the solution are altered so that no more SO2 may be dissolved in the volume of liquid provided. Under these circumstances, sampling is 100% efficient for a limited total mass of SO2 transferred to the solution, and the technique is acceptable as long as sampling does not continue beyond the time that the sampling solution is saturated (1). A second example is the use of solid sorbents such as Tenax... 

Several manual and continuous analytical techniques are used to measure SO2 in the atmosphere. The manual techniques involve two-stage sample collection and measurement. Samples are collected by bubbling a known volume of gas through a liquid collection medium. Collection efficiency is dependent on the gas-liquid contact time, bubble size, SO2 concentration, and SO2 solubility in the collection medium. The liquid medium contains chemicals which stabilize SO2 in solution by either complexation or oxidation to a more stable form. Field samples must be handled carefully to prevent losses from exposure to high temperatures. Samples are analyzed at a central laboratory by an appropriate method. 

The continuous methods combine sample collection and the measurement technique in one automated process. The measurement methods used for continuous analyzers include conductometric, colorimetric, coulometric, and amperometric techniques for the determination of SO2 collected in a liquid medium (7). Other continuous methods utilize physicochemical techniques for detection of SO2 in a gas stream. These include flame photometric detection (described earlier) and fluorescence spectroscopy (8). Instruments based on all of these principles are available which meet standard performance specifications. 

In many cases, water is a poor scrubbing solvent. Sulfur dioxide, for example, is only slightly soluble in water, so a scrubber of very large liquid capacity would be required. SO2 is readily soluble in an alkaline solution, so scrubbing solutions containing ammonia or amines are used in commercial applications. 

By-product processing Hydrogen sulfide Conversion to elemental sulfur or sulfuric acid by liquid absorption, wet oxidation to elemental sulfur, combustion to SO2... 

Thiazyl salts were first prepared in 1971 by the reaction of NSF with AsFs or SbFs. They may also be obtained from (NSC1)3 by reaction with (a) AgiAsFe] in liquid SO2 (Eq. 5.9) or (b) AICI3 in CH2CI2 under the influence of heat or ultrasound. ... 

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