Electrolysis in liquid

This technique is useful for monomers which are difficult to polymerize by other techniques. Thus, chlorotrifluoroethylene can be polymerized anodically with good efficiency by electrolysis in liquid hydrogen fluoride - potassium fluoride or trifluoroacetic acid - trifluoroacetic anhydride - potassium trifluoroacetate 631 ... 

With minor modifications, the setup can also be used with a solid working electrode, or for nonaqueous electrolyte solutions. H-cells with solid plane parallel electrodes of the same area are frequently utilized for work in anhydrous media, also since they provide a uniform current distribution. A small distance between the electrodes, not only for this cell design, makes them suitable for work in media of low electrical conductivity. The cell design can be used for electrolysis in liquid ammonia, if a connection between the anode and cathode compartment above the solution level is ensured, to equilibrate the pressure in the system [iii]. 

Alkyl mercuric halides, electrolysis in liquid ammonia, 30, 31,... 

In an H cell for electrolysis in liquid ammonia, a connection between the anode and cathode chamber above the level of the solution is necessary to equilibrate the pressure in the system [49]. 

Electrolysis in liquid HF is an important preparative route to both inorganic and organic fluorine-containing compounds, many of which are difficult to access by other routes. Anodic oxidation in liquid HF involves half-reaction 8.45 and with NH4F as substrate, the products of the subsequent fluorina-tion are NFH2, NF2H and NF3. 

The preparation of a fully fluorinated organic compound tends therefore to be carried out in an inert solvent (the vaporization of which consumes the heat liberated) in a reactor packed with gold- or silver-plated copper turnings (which similarly absorb heat but may also play a catalytic role). Other methods include use of C0F3 or AgF2 as fluor-inating agents, or electrolysis in liquid HF (see Section 8.7). 

For estimation of the current bypass in bipolar electrode stacks, the following model was proposed for water electrolysis in liquid electrolytes. In an electrode stack composed of N individual cells, the potential difference between the two terminal feeder electrodes, Fn, is given as the sum of the individual cell voltages, Vf... 

Since the proton affinity of hydrazine is similar to that of ammonia, acid-base reactions are similar to those in this solvent system. Many compounds are known to act as moderately strong acids, but only a few substances (notably the hydra-zides of the alkali metals) behave as bases. NaN2H3 may be obtained by drop wise addition of hydrazine to a suspension of finely divided sodium in dry ether. Electrolysis in liquid hydrazine gives nitrogen at the anode and hydrogen at the cathode . 

OF2 is produced by electrochemical conversion of O2 in the electrolysis of an essentially anhydrous HF electrolyte (<0.1 wt% H2O) with added NH4F or alkali metal fluorides at 60 to 105°C. The anode had pores through which O2 was introduced [10]. Electrolysis of a melt consisting of -60% KF, -39% HF, and -1% LiF, to which was added up to 1% H2O, yields OF2. The water may be replenished by a stream of moist air [11]. In almost all cases of fluorination of oxygen-containing inorganic compounds by electrolysis in liquid HF, the initially generated gas contains OF2 (38 to 64 vol%). However, the OF2 concentration drops to zero in the course of the electrolysis [12]. 

Nesvadba and Roth [66] have provided a description of an apparatus and have developed standardized conditions for the sodium-ammonia reduction. The reduction is relatively unselec-tive and removes iV-benzylcarbonyl, iV-tosyl, JV-trityl, as well as N- and O-benzyl groups. Recently Ives [67] has proposed that S-benzyl groups could be removed by electrolysis in liquid ammonia. 

Hydrazine is prepared, anhydrous and in good yield, by glow discharge electrolysis of liquid ammonia a platinum cathode is immersed in liquid and a platinum wire anode is mounted just... 

Types of Gas-in-Liquid Dispersions Two types of dispersions exist. In one, gas bubbles produce an unstable dispersion which separates readily under the influence of gravity once the mixture has been removed from the influence of the dispersing force. Gas-hquid contacting means such as bubble towers and gas-dispersing agitators are typical examples of equipment producing such dispersions. More difficulties may result in separation when the gas is dispersed in the form of bubbles only a few micrometers in size. An example is the evolution of gas from a hquid in which it has been dissolved or released through chemical reaction such as electrolysis. Coalescence of the dispersed phase can be helpful in such circumstances. 

Fluorine comes from the minerals fluorspar, CaF, cryolite, Na3AlF6 and the fluorapatites, Ca,F(P04)3. The free element is prepared from HF and KF by electrolysis, but the HF and KF needed for the electrolysis are prepared in the laboratory. Chlorine primarily comes from the mineral rock salt, NaCl. The pure element is obtained by electrolysis of liquid NaCl. Bromine is found in seawater and brine wells as the Br ion it ts also found as a component of saline deposits the pure element is obtained by oxidation of Br (aq) by Cl,(g). Iodine is found in seawater, seaweed, and brine wells as the I" ion the pure element is obtained by oxidation of I (aq) by Cl,(g). 

The electrolysis of quaternary ammonium salts in liquid ammonia gives blue solutions like those of the alkali metals in liquid ammonia.146... 

Schuster had an informed interest in chemical problems. He taught a course in chemical physics that was attended by chemistry honors students. Topics included spectrum analysis, saccharimetry, and electrolysis. In 1894, he organized a fortnightly "physical colloquium" for second- and third-year physics students joined by some chemistry honors students. He closely followed the chemical research of his colleagues, Roscoe and Harold Baily Dixon. In interpreting results in his special field of spectroscopy and in electrochemistry, Schuster visualized an "ionic" mechanism of electrical conduction in liquids and gases.60... 

Sodium amide has been prepared by the action of gaseous 2 or liquid3 ammonia on sodium, by the action of ammonia on alloys of sodium,4 and by the electrolysis of a solution of sodium cyanide 5 in liquid ammonia with a sodium amalgam electrode. A summary of the chemistry of alkali amides is given by Bergstrom and Fernelius.1... 

If an actinide metal is available in sufficient quantity to form a rod or an electrode, very efficient methods of purification are applicable electrorefining, zone melting, and electrotransport. Thorium, uranium, neptunium, and plutonium metals have been refined by electrolysis in molten salts (84). An electrode of impure metal is dissolved anodically in a molten salt bath (e.g., in LiCl/KCl eutectic) the metal is deposited electrochemically on the cathode as a solid or a liquid (19, 24). To date, the purest Np and Pu metals have been produced by this technique. 

---