Chloride ions aluminum

Aluminum bronzes Hydrofluoric acid, acids containing chloride ions Aluminum (dealuminification)... 

Many stabilizer systems have been tailored to a particular industry need or for particular areas where dilution water quaUty is poor. These grades are heavily stabilized and may contain organic sequestering agents, ie, staimate, phosphates, and nitrate ions, so that the weak solutions produced by dilution from hard water retain acceptable stabihty. The nitrate is not a stabilizer, but it inhibits corrosion of aluminum storage tanks by chloride ion. 

Crevice Corrosion. Crevice corrosion is intense locali2ed corrosion that occurs within a crevice or any area that is shielded from the bulk environment. Solutions within a crevice are similar to solutions within a pit in that they are highly concentrated and acidic. Because the mechanisms of corrosion in the two processes are virtually identical, conditions that promote pitting also promote crevice corrosion. Alloys that depend on oxide films for protection (eg, stainless steel and aluminum) are highly susceptible to crevice attack because the films are destroyed by high chloride ion concentrations and low pH. This is also tme of protective films induced by anodic inhibitors. 

The properties of 1,1-dichloroethane are Hsted ia Table 1. 1,1-Dichloroethane decomposes at 356—453°C by a homogeneous first-order dehydrochlofination, giving vinyl chloride and hydrogen chloride (1,2). Dehydrochlofination can also occur on activated alumina (3,4), magnesium sulfate, or potassium carbonate (5). Dehydrochlofination ia the presence of anhydrous aluminum chloride (6) proceeds readily. The 48-h accelerated oxidation test with 1,1-dichloroethane at reflux temperatures gives a 0.025% yield of hydrogen chloride as compared to 0.4% HCl for trichloroethylene and 0.6% HCl for tetrachloroethylene. Reaction with an amine gives low yields of chloride ion and the dimer 2,3-dichlorobutane, CH CHCICHCICH. 2-Methyl-l,3-dioxaindan [14046-39-0] can be prepared by a reaction of catechol [120-80-9] with 1,1-dichloroethane (7). 

The corrosion resistance of aluminum and its alloys tends to be veiy sensitive to trace contamination. Veiy small amounts of metalhc mer-cuiy, heavy-metal ions, or chloride ions can frequently cause rapid failure under conditions which otherwise would be fuUy acceptable. 

Figure 2-11 shows weight loss rate-potential curves for aluminum in neutral saline solution under cathodic protection [36,39]. Aluminum and its alloys are passive in neutral waters but can suffer pitting corrosion in the presence of chloride ions which can be prevented by cathodic protection [10, 40-42]. In alkaline media which arise by cathodic polarization according to Eq. (2-19), the passivating oxide films are soluble ... 

Other passivating materials suffer pitting corrosion by chloride ions [62] in a way similar to stainless steels (e.g., Ti [63] and Cu [64]). The pitting potential for aluminum and its alloys lies between = -0.6 and -0.3 V, depending on the material and concentration of chloride ions [10,40-42]. 

Aluminum alloys Chloride ion Organics High-purity hot water... 

For alkaline duty, steel can sometimes be used up to approximately pH 11. Zinc, aluminum and similar metals and their alloys have limited use in alkaline conditions because they dissolve, giving complex anions. Iron and steel react in this way above about pH 12. Approximate limits of use for zinc are pH 6-12 and aluminum alloy pH 4-8. Stainless steels, including the lower grades, can be used even in the presence of chloride ions at pH levels of approximately In the absence of halides they can be used up to about pH 13. 

Free-ion attack is more likely for sterically hindered R. ° The ion CH3CO " has been detected (by IR spectroscopy) in the liquid complex between acetyl chloride and aluminum chloride, and in polar solvents such as nitrobenzene but in nonpolar solvents such as chloroform, only the complex and not the free ion is present. In any event, 1 mol of catalyst certainly remains complexed to the product at the end of the reaction. When the reaction is performed with RCO" SbF6, no catalyst is required and the free ion (or ion pair) is undoubtedly the attacking entity. ... 

The Alclad alloys have been developed to overcome this shortcoming. Alclad consists of a pure aluminum layer metallurgically bonded to a core alloy. The corrosion resistance of aluminum and its alloys tends to be very sensitive to trace contamination. Very small amounts of metallic mercury, heavy-metal ions, or chloride ions can frequently cause rapid failure under conditions which otherwise would be fully acceptable. When alloy steels do not give adequate corrosion protection—particularly from sulfidic attack—steel with an aluminized surface coating can be used. 

Unlike cyclohexene, its oxa analog, 3,4-dihydro-2//-pyran, undergoes facile reduction to tetrahydropyran in yields ranging from 70 to 92% when treated with a slight excess of triethylsilane and an excess of either trifluoroacetic acid or a combination of hydrogen chloride and aluminum chloride (Eq. 69).146 This difference in behavior can be understood in terms of the accessibility of the resonance-stabilized oxonium ion intermediate formed upon protonation. 

When the solvent is evaporated, a solid is obtained that contains the hydrated aluminum ion and chloride ions. This solid can be described as [A1(H20)6]C13, although the number of water molecules may depend on the conditions. When this solid is heated, water is lost until the composition [A1(H20)3C13] is approached. When heated to still higher temperature, this compound loses HC1 rather than water ... 

Chlorine as a free element is diatomic (Cl2) however, as an ion, it will gain one electron to become isoelectronic with argon. The electronic configuration of the chloride ion is s22s22p63s23p6. The compound thus formed, aluminum chloride, has the formula A1C13. 

Treatment of lead(n) chloride with aluminum trichloride and o-xylene furnishes bis(o-xylene)lead(ll) bis(tetrachloro-aluminate) 41. According to the results of an X-ray structure determination, 41 consists of a monomeric complex with two arene ligands in a distorted 77-mode of coordination and two bidentate AICI4- ions at the central Pbz+ ion. The interaction of the lead center with the tetrachloroaluminate ligands is presumably highly ionic, suggesting that 41 is a triad of arene-stabilized ions, rather than a molecule.7... 

Reacts with sodium and potassium permanganates (oxidizing agents) yielding carbon dioxide, water, and chloride ions. Incompatible with other strong oxidizing agents (e.g., ozone), aluminum and its alloys. 

In military aerospace vehicles, the service conditions are most severe for paints. One way to increase protecion of aluminum in acidic marine environments is to enhance the corrosion inhibiting ability of the inorganic coating. This paper describes the results of such an effort. A new coating which not only inhibits the attacic of chloride ions but also that of the acidic environments such cis SO2 has been developed. 

A reaction in which an electrophile participates in het-erolytic substitution of another molecular entity that supplies both of the bonding electrons. In the case of aromatic electrophilic substitution (AES), one electrophile (typically a proton) is substituted by another electron-deficient species. AES reactions include halogenation (which is often catalyzed by the presence of a Lewis acid salt such as ferric chloride or aluminum chloride), nitration, and so-called Friedel-Crafts acylation and alkylation reactions. On the basis of the extensive literature on AES reactions, one can readily rationalize how this process leads to the synthesis of many substituted aromatic compounds. This is accomplished by considering how the transition states structurally resemble the carbonium ion intermediates in an AES reaction. 

Friedel-Crafts reactions are electrophilic substitution reactions in which the electrophile is a Ccirbocation or an acylium ion. The removal of a halide ion from an alkyl halide is the means of generating the ceirbocation. An acylium ion is created by removing a chloride ion from an acid chloride (R-CO-Cl). Both of these processes require a Lewis acid as a catalyst. The most commonly used Lewis acid is aluminum chloride. 

Acridizinium chloride is easily chlorinated by the action of sulfuryl chloride containing aluminum chloride to give 7,10-dichloroacridizinium ion. It has not been demonstrated that an electrophilic substitution is involved and if so in what order the two substituents are introduced. 

Fig. 5.2.6 SEM images of the ellipsoidal particles of basic aluminum sulfate prepared in the presence of 1.67 mol dm-3 chloride ions under the otherwise standard conditions. (From Ref. 1.)...

A family of high performance and clean space motor/gas generators and large launch vehicle solid propellants based on poly(GlyN) binder, ammonium nitrate oxidizer and small amounts of aluminum and/or boron with optimized performance at low solids loading (without the presence of plasticizers) and also poly(GlyN) binder, ammonium nitrate oxidizer and aluminum or magnesium fuel have been reported in the literature [141, 142]. These solid propellant formulations produce essentially no HC1 or chloride ions in the exhaust and are considered eco-friendly. 

Figure P6.4 shows the logarithmic dependence of the adsorption of chloride ions, log(T - r/r, on time, /(min). The adsorbing metal is aluminum, the concentration of chloride ions in solution is 1(T3 mol dm-3 at pH 12, and the potential in the hydrogen scale is -0.9 V. On the assumption that the adsorption is diffusion controlled, determine the standard free energy of adsorption of chloride ions on the surface concerned. 

Fig. P6.4. Logarithmic dependence of adsorption on time for 10-3 M chloride ions on aluminum at pH 12, V= -0.9 V. (Reprinted from J. O M. Bockris and L. Minevski, J. Electroanal. Chem. 349 375, copyright 1993, Fig. 4, with permission of Elsevier Science.)...

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