Cyclic salts

Electrophilic attack on the sulfur atom of thiiranes by alkyl halides does not give thiiranium salts but rather products derived from attack of the halide ion on the intermediate cyclic salt (B-81MI50602). Treatment of a s-2,3-dimethylthiirane with methyl iodide yields cis-2-butene by two possible mechanisms (Scheme 31). A stereoselective isomerization of alkenes is accomplished by conversion to a thiirane of opposite stereochemistry followed by desulfurization by methyl iodide (75TL2709). Treatment of thiiranes with alkyl chlorides and bromides gives 2-chloro- or 2-bromo-ethyl sulfides (Scheme 32). Intramolecular alkylation of the sulfur atom of a thiirane may occur if the geometry is favorable the intermediate sulfonium ions are unstable to nucleophilic attack and rearrangement may occur (Scheme 33). 

The evaporite source is characterized by covariation of sulfate (from gypsum) and chloride (from halite). That elements can be recycled from the ocean to land by movement of saltbearing aerosols (so-called "cyclic salts") has confused the interpretation of river flux data somewhat. While this cycling generally follows the ratio of salts in the sea, the S/Cl ratio is an exception. Taking the S/Cl ratio of the cyclic component to be 2 (based on compositional data for marine rains) and assuming that all chloride in rivers is cyclic, an upper limit for the cyclic influence can be calculated. 

Acetals of diphenylphosphinoacetaldehyde react with hydrogen bromide in boiling glacial acetic acid to give the cyclic salts (80). 

Once in the atmosphere, the water evaporates and some of the sea salt falls back to the sea surfece. The rest is transported considerable distances by winds imtil it is washed out of the atmosphere by rainfall. The salts that are transported back to the continents by this process are termed cyclic salts. After having been rained out onto the continents, the salts are carried back into the ocean by river runoff On short time scales, the global cycling of chlorine and sodium are dominated by this process. The cyclic salts are discussed further in Chapter 21. 

Cyclic Salt Carbonates Silicates Evaporites Pollution ... 

The major ions have two main escape routes from the ocean (1) incorporation into sediments or pore water and (2) ejection into the atmosphere as seasalt spray. This spray is caused by bursting bubbles that produce small particles, called aerosols, that range in diameter from 0.1 to 1000 pm. The annual production rate of seasalt aerosols is large, on the order of 5 x lO kg/y, but virtually all of it is quickly returned when the spray fells back onto the sea surfece. A small fraction (about 1%) is deposited on the coastal portions of land masses and carried back into the ocean by river runoff. As shown in Table 21.6, seasalts represent a significant fraction of dissolved solids in river runoff, especially for sodium and chloride. Due to the short timescale of this process, seasalt aerosol losses and inputs are considered by geochemists to be a short circuit in the crustal-ocean-atmosphere fectory. The solutes transported by this process are collectively referred to as the cyclic salts. ... 

Cyclic salts Salt ions that undergo rapid cycling between the ocean, atmosphere and land. This cycle involves ejection into the atmosphere via bursting bubbles and return via either dry deposition onto the sea surface or onto land followed by runoff back into the ocean. 

To evaluate the net riverine influx of dissolved species to the ocean, the river load has to be corrected for sea salts transported via the atmosphere from the ocean to the continents and rained out mainly in coastal precipitation. Table 9.7 shows the average concentration of selected dissolved and particulate elements in rivers from Martin and Meybeck (1979), and the corresponding net fluxes corrected for sea-salt cycling from Martin and Meybeck (1979). The corrections of fluxes for cyclic salts and pollution are still debatable estimates (e.g., Holland, 1978 Maynard, 1981), and affect mainly the evaluation of the net flux of Na+ by perhaps as much as 20%. 

Much has been written in recent years about atmospheric inputs to the soil since the acid rain problem has been recognised. Soils receive both wet deposition, ie, precipitation as rain or snow and dry deposition in which aerosols are deposited on the surface. Although precipitation is very dilute it can be an important source for some elements, cyclic salts which are derived from the oceans and transported to the land surface in the normal hydrological cycling of elements. Fuge and Johnson (1986) concluded that most iodine in soils is derived from the atmosphere and, hence, the oceans. Normally, however, rain makes only a very small contribution to the composi-... 

Methide electrolytic salts have also been prepared (3). This is illustrated in Eq. 1 and Eq. 2 for linear and cyclic salts, respectively. 

Another form of removal through the water-atmosphere interphase is aerosol formation in marine surface waters where salt spray tends to remove mainly NaCl, NaS04, and MgS04. These are generally known as cyclic salts due to their potential return to the sea through rain washout. 

It is interesting to note that the cyclic salt 12 did not react with benzenesul-finic acid however, when treated with sodium benzenesulfinate in an alcohol, it gave dibenzoselenophene 21 and Z-alkoxyvinylsulfones 17a-c in moderate yields (51-77%). When the reaction was carried out in t-butyl alcohol, bis(phenylsulfonylvinyl)ether (22) was formed in 30% yield (Eq. 4). 

The kinetic results625 showed that plots of the /n[styrene] vs. time, reproduced in Fig. 50, to be sigmoidal, indicating a strong acceleration of the reaction with the increasing conversion. Such results were rationalized by assuming that only the open form of the cyclic salt is responsible for the propagation... 

Mizuno et al. reported an interesting example of an intramolecular N-alkylation of IbP 3-)3-D-ribofuranosyl-3H-IbP 5 -tosylate 265 refluxed in acetone afforded cyclic salt 266 (63CPB265). 

Share analytical equipment, technicians, and methods. Special laboratory equipment can cost a lot of money and in some cases is not continually used. Specialized equipment purchases can be shared and both companies can reap the benefits of the equipment. A specific example of this would be an NMR spectrometer or a cyclical salt spr apparatus. 

D5894—10 Standard Practice for Cyclic Salt Fog/UV Exposure of Painted Metal, (Alternating Exposures in a Fog/Dry Cabinet and a UV/Condensation Cabinet)... 

ASTM D5894-10, Standard practice for cyclic salt fog/UV exposure of painted metal (alternating exposures in a fog/ dry cabinet and a UV/ condensation cabinet, in Annual Book of ASTM Standards, Vol. 06.01, ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA, 2010. 

Standard Practice for Cyclic Salt Fog/UV Exposure of Painted Metal... 

ASTM D 5894, Standard Practice for Cyclic Salt Fog/UV Exposure of Painted Metal, was adopted in 1996 and incorporates a UV exposure cycle following G 85 Annex 5 exposure [9]. The addition of the UV exposure cycle added a weathering effect to the test conditions and produced results that more closely resembled field exposure. Due to the alternating Salt Fog/UV exposure, two separate test chambers are required. 

Annex A3 describes a cyclic salt spray test (SWAAT) that uses a different exposure cycle and a 5 % synthetic sea salt solution acidified to pH 3 with acetic acid in a spray chamber at a temperature of 49°C (120°F). This test is applicable to the production control of exfoliation-resistant tempers of the AA2XXX, AA5XXX, and AA7XXX aluminum alloys. Wet-bottom operating conditions are recommended with test durations of 1-2 weeks [13,14],... 

The current salt spray test, in which the plated specimen is exposed to a spray or fog of sodium chloride solution, is the most widely used accelerated corrosion test for coatings, and various procedures have acceptance tests in standard specifications in numerous countries. Over the years, the procedure has employed sodium chloride solutions of concentrations between 3 and 20 %, sometimes with the addition of hydrochloric acid or hydrogen peroxide. The salt spray test [ASTM B 117, Test Method of Salt Spray (Fog) Testing] has largely fallen into disrepute because of the recognition that its reproducibility and correlation with outdoor exj>osure were often poor. Cyclic salt spray testing as well as alternate electrolytes such as the "prohesion test solution have been found to produce more realistic results. 

Applicable test methods include [28] Continuous Salt Spray Tests (ASTM B 117), Neutral Salt Spray Test (ASTM B 117), Acetic Acid Salt Spray Test, Copper-Accelerated Salt Spray Test (CASS) (ASTM B 368), Cyclic Salt Spray Tests, the Copper Development Association (CDA) Test, the Hitachi Salt Spray Test, Climate Tests, The Humidity Test, The International Electrotechnical Commission/Intemational Organization for Standardization (lEC/ISO) Test and Mud Test. 

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