Containers halides

Combustion Many organic compounds released from manufacturing operations can be converted to innocuous carbon dioxide and water by rapid oxidation (chemical reaction) combustion. However, combustion of gases containing halides may require the addition of acid gas treatment to the combustor exhaust. 

Type 316-This has a composition of 17/12/2.5 chromium/nickel/molyb-denum. The addition of molybdenum greatly improves the resistance to reducing conditions such as dilute sulfuric acid solutions and solutions containing halides (such as brine and sea water). 

The outstanding resistance to corrosion exhibited by the high-silicon alloys is believed to be due to the development of a corrosion-resistant film containing a large proportion of silica. The full protective value of the film does not develop for most applications until at least 14-25% silicon is present in the alloy (Fig. 3.61). Increase in the content of silicon above 14-5% does not have a dramatic effect upon the corrosion resistance of the alloy (Fig. 3.61), although the further increase in film density is of service if the casting is to be exposed to solutions containing halide ions, especially hydrochloric acid. 

In the case of ions, the repulsive interaction can be altered to an attractive interaction if an ion of opposite charge is simultaneously adsorbed. In a solution containing inhibitive anions and cations the adsorption of both ions may be enhanced and the inhibitive efficiency greatly increased compared to solutions of the individual ions. Thus, synergistic inhibitive effects occur in such mixtures of anionic and cationic inhibitors . These synergistic effects are particularly well defined in solutions containing halide ions, I. Br , Cl", with other inhibitors such as quaternary ammonium cations , alkyl benzene pyridinium cations , and various types of amines . It seems likely that co-ordinate-bond interactions also play some part in these synergistic effects, particularly in the interaction of the halide ions with the metal surfaces and with some amines . 

The complexed halide atoms are produced by high energy radiation in solutions of colloids that contain halide anions X and are saturated with nitrous oxide. Hydrated electrons formed in the radiolysis of the aqueous solvent react with NjO according to NjO -f e -f H O - Nj -t- OH -I- OH to form additional OH radicals. Ions X are oxidized by OH, the atoms X thus formed react rapidly with X to yield XJ radicals. 

Since analogous ketoesters not containing halide could be hydrogenated in good yield, the acidity of the enolate seems to be the main reason for the replacement of the aminoalcohol ligand by the halogenated acetoacetate. Indeed,... 

Pharmaceutical substances essentially containing halides may be estimated by direct titration with silver nitrate solution as a titrant. 

Ketones and aldehydes (51) are oxidized to a-hydroxy ketals and acetals (52) by electrolysis in MeOH containing halide ion under basic conditions (Eq. 9) [88]. 

Consider a system in which a silver halide membrane AgX separates solution 1, containing halide ions at concentration c x and ions forming a complex with silver ion in concentration Y, from solution 2, containing halide ions at concentration The exchange reaction... 

It is not possible to carry out the reaction between hydroxylamine and an ester under neutral conditions (Scheme 49) since it always requires a pH >10. Hence, this method is not suitable for ester derivatives that contain halides, and other base-sensitive groups. 

The competitive formation of dinudear complexes containing halide bridging systems has also been reported (representative examples are shown in Figure 2.5) [21]. 

Most HPLC equipment currently available has a high tolerance to most mobile-phase conditions that can be contemplated for use in RPC applications with peptides. If it is intended to use mobile phases containing halide salts in RPC separations of peptides with standard HPLC equipment made from type 316 stainless steel, it is essential that the equipment is properly flushed with neat water when not in operation to avoid corrosion by the residual halide ions, especially at low pH. Otherwise, the use of the less popular biocompatible metal-free HPLC equipment, marketed by several manufacturers, avoids potential problems of equipment malfunction due to corrosion of the stainless steel or the contamination of peptide samples by low levels of leached metal ions. With such metal-free HPLC equipment, titanium, glass, or perfluoro-polymeric components have been used to replace any wettable stainless steel components. 

Lever has successfully predicted Mn"/ potentials of 24 Mn-carbonyl complexes containing halide, pseudohalide, isonitrile, and phosphine co-ligands, with additivity parameters derived from the potentials of Ru "/" couples [39]. An important consideration for heteroleptic complexes is the influence of isomerism on redox thermodynamics. For Mn(CO) (CNR)6- complexes, with n = 2 or 3, the Mn"/ potentials for cis/trans and fac/mer pairs differ by as much as 0.2 V [40]. The effect arises from the different a-donor and 7r-acceptor abilities of carbonyl (CO) and isocyanide and their influence on the energy of the highest energy occupied molecular orbital (HOMO). 

The reliable prediction of redox potentials as a function of composition is useful in the synthetic design and application of technetium and other transition metal complexes. A parametric procedure for doing so on the basis of ligand additivity principles has been developed by Lever [28]. Lu etal. [29] used this scheme to correlateTc / ",Tc "/ , andTc hi potentials with the composition of octahedral technetium complexes containing halide, nitrogen, and phosphorus donor ligands. The results are illustrated in Fig. 2 [29], where the observed potentials are plotted according to... 

Addition of chlorine or bromine in the presence of water can yield compounds containing halide and hydroxyl on adjacent carbon atoms (haloalcohols or halohydrins). The same products can be obtained in the presence of methanol (13) or acetic acid (14). As expected from the halonium ion intermediate, the addition is anti. As expected from Markovnikov s rule, the positive halogen goes to the same carbon that the hydrogen of a protic reagent would. 

The most usual synthetic routes to the derivatives of platinum group metals are the exchange reactions of the complexes containing halide ligands with alkali metal alkoxides (method 5), alcoholysis of the same kind derivatives (usually by phenols, method 4), alcoholysis of hydroxide complexes (method 3), and redox reactions — reduction of chlorides or 0s04 in alcohol media (method 7) (Table 12.25). 

For this reason, gold electrodes should not be used at highly positive potentials in solutions that contain halides or other complexing ions. 

SCHEME 17. Estertin compounds containing halide or pseudohalide as ligand... 

The method can be used for certain transition metal complexes containing halides or other labile ligands. For example, this method has been used for the preparation of a bis-NHC - Au(I) complex, starting from AuCl(SMe2), AuCN [162], AuCl(THT) [163], (THT = tetrahydrothio-phene) [162], AuCl(PPh3) [162], and [MCl(CO)5]- (M = Cr, W) [164]. 

The active center formed by the interaction of butadiene with bis( r-crotylnickel chloride) or the products of the reaction of (C4H7NiX)2 + Lewis acids does not contain halides, and there is no steric hindrance for syn complex to be isomerized into an anti complex, which is more stable thermodynamically according to Bank (2). 

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