Formamide transport

The activity and osmotic coefficients of sodium thiocyanate in water have been determined (531). The solvation number of NCS has been reported as zero. (588), and the ion tends to be less structure-breaking than most anions (136). Its transport number and ionic conductance have been measured in formamide (581), and 1 1 solvates have been reported from dimethylformamide solutions of M—NCS (M = NH4, Na, K) (595). 

Cation was found to be the key parameter influencing both the nanotube growth rate and length [49], With increasing cation size, the interfacial oxide layer was getting thinner. Ionic transport was facilitated and the nanotube growth was enhanced. The thinnest nanotubes ever reported was 5 nm, which was obtained in an electrolyte containing 0.5 M tetrabutylammonium fluoride in formamide with 5% water (Fig. 8). 

Polymer membranes have also been used as a "sandwich". In this configuration, the liquid film is supported between two polymer membranes. Ward (18) used two silicone rubber membranes to contain a solution of ferrous ions in formamide. Ward noted that Bernard convection cells could be maintained if the complex were formed at the upper surface. Ward (19) used this same system and membrane configuration to study electrically-induced, facilitated gas transport. The silicone rubber membranes provided the mechanical support so the electrodes could be placed next to each liquid surface. Otto and Quinn (20) immobilized the liquid film in a horizontal layer between two polymer films. The polymer was described as an experimental silicone copolymer having high CO2 permeability as well as excellent mechanical properties. They were studying CO2 facilitated transport in bicarbonate solutions with and without carbonic anhydrase. 

Aprotic solvent enhanced transport (n-Methyl-2-Pyrrolidone, Pyrrolidone, Dimethyl acetamide, Dimethyl formamide, Dimethyl isosorbide)... 

Notwithstanding the non-specific role of water in many non-aqueous solutions, in some cases it may have specific effects due to ion-water interactions which depend on the particular nature of the ions and solvent. Thus the conductance of associated AgNOa and (CHajaTlI in dimethyl-formamide increase with the water content in contrast to the decrease found for dissociated salts In methanol and ethanol the conductance of perchloric acid (and presumably of other Inorganic acids) decreases significantly upon addition of 0.3 % water. This was attributed to a change in the proton transport mechanism. 

The crude product consists of 60 to 70 vol. % of HCN. The process is of interest for the in situ manufacture of small amounts of hydrogen cyanide. Because the transport of formamide is easier and safer than that of methane, ammonia, or HCN, the process is useful for areas where methane and ammonia are unavailable. The conversion of formamide to HCN (Reaction 3) is reported to be in the range of 92 to 95 mole %. 

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