FeCl2 cathode

It has recently been reported that a molecule, claimed to contain a high concentration of conjugated alkyne units, can be prepared by electrochemical reduction of polytetrafluoroethylene (PTFE) [32,33]. The reduction is carried out using magnesium and stainless steel as anode and cathode respectively. The electrolyte solution contains THE (.30 cm ), LiCI (0.8 g) and FeCl2 (0.48 g). A 10 X 10 nm PTFE film, covered with solvent, is reduced to carbyne (10 V for 10 h)... 

Different reactions (anodic and cathodic) can occur simultaneously at an electrode, even when there is no net current flow. In Section 2.5.1 we mentioned the example of an iron electrode in HCl + FeCl2 solution where anodic iron dissolution (2.24) and cathodic hydrogen evolution (2.25) occur simultaneously these are the reactions of spontaneous dissolution of iron not requiring a net current. 

An electric current is applied to an aqueous solution of FeCl2 and ZnCl2. Which of the following reactions occurs at the cathode ... 

Carbanions occasionally react with aryl halides spontaneously, mostly under irradiation, or by supplying electrons either from dissolved metals or from a cathode. However, certain Fe+2 salts catalyse the S l reactions with carbanions. That was the case for the reaction of PhBr or Phi with acetone or pinacolone enolate ions in liquid ammonia or DMS0172a, as well as for the reaction of the enolate ion of several carbanions with several aryl and hetaryl halides in DMS0172b. Since these reactions are inhibited byp-DNB andp-cymene, and the relative reactivity of nucleophiles is similar to that determined in photo-stimulated or spontaneous reactions, it seems that FeCl2 initiates the S l process. 

In sodium chloride solutions, on the other hand, the conductivity is greater hence, additional anodes and cathodes can operate much further removed one from the other. At such cathodes, NaOH does not react immediately with FeCl2 formed at anodes instead, these substances diffuse into the solution and react to form Fe(OH)2 away from the metal surface. Any Fe(OH)2 so formed does not provide a protective barrier layer on the metal surface. Hence, iron corrodes more rapidly in dilute sodium chloride solution because more dissolved oxygen can reach cathodic areas. Above 3% NaCl, the continuing decreased solubility of oxygen becomes more important than any change in the diffusion-barrier layer hence, the corrosion rate decreases. 

This area will be passivated by the increase in pH due to the cathodically produced OH ions, and partially cathodically protected by the electrons liberated by the anodic processes within the pit. The tubercle thus results in an occluded cell with the consequent acidification of the anodic sites. Wranglen considers that in view of the fact that crystals of FeCl2 -4H20 are sometimes observed at the bottom of a pit the solution within the pit is a saturated solution of that salt, and that this will correspond with an equilibrium pH of about 3-5. 

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