Acids zinc chloride

Attempted Nitration of MeNGu Various methods of nitration were attempted including nitric acid alone, or in combination with 100% perchloric acid, zinc chloride, perboric acid, boron trifluoride, etc. All of them gave MeNGu nitrate, described above, but no nitro derivatives (Ref 7, p 3029)... 

Furthermore, the reaction of aromatic ethers with a stoichiometric amount of BTMA Br3 in dichloromethane-methanol or acetic acid-zinc chloride under mild conditions gave, selectively, mono-, di-, or tribromo-substituted aromatic ethers in quantitative yields (Fig. 10) (ref. 15). 

According to the submitters, yields of the order of 95 per cent of other acid chlorides can be obtained by the use of phthal-oyl chloride (1 mole of chloride to 1 mole of a monobasic acid, 2 moles of chloride to 1 mole of a dibasic acid). Zinc chloride, as catalyst, is not necessary in the reaction of most acids and their anhydrides with phthaloyl chloride. When acids are used, it is best to add one of the components slowly, in order to avoid a too violent evolution of hydrogen chloride on wanning. 

A similar mechanism to the previous ones was proposed by Deng, Shi and coworkers for the bis(2-oxo-3-oxazolidinyl)phosphinic chloride (BOP-Cl, 269) catalytic Beckmann rearrangement (equation 82). Addition of the Lewis acid zinc chloride improved the catalyst performance and amides were synthesized in excellent yields (92-99%). 

The prominent role of alkyl halides in formation of carbon-carbon bonds by nucleophilic substitution was evident in Chapter 1. The most common precursors for alkyl halides are the corresponding alcohols, and a variety of procedures have been developed for this transformation. The choice of an appropriate reagent is usually dictated by the sensitivity of the alcohol and any other functional groups present in the molecule. Unsubstituted primary alcohols can be converted to bromides with hot concentrated hydrobromic acid.4 Alkyl chlorides can be prepared by reaction of primary alcohols with hydrochloric acid-zinc chloride.5 These reactions proceed by an SN2 mechanism, and elimination and rearrangements are not a problem for primary alcohols. Reactions with tertiary alcohols proceed by an SN1 mechanism so these reactions are preparatively useful only when the carbocation intermediate is unlikely to give rise to rearranged product.6 Because of the harsh conditions, these procedures are only applicable to very acid-stable molecules. 

Methylbenzo[ ]thiophene is available through the interaction of sodium benzenethiolate and chloroacetone, followed by the cyclization of the initial product by the action of a Lewis acid, zinc chloride (Scheme 7.23c). 

Lewis acids zinc chloride or aluminum chloride. Heat alone is sometimes effective, and the kinetics of the formation of dibenzofuran from 2,2 -biphenyldiol have been studied in both the presence and absence of zinc chloride. The rate and the degree of conversion are both markedly increased with increasing temperature under these conditions. ... 

Several catalysts have been recommended for the N-acetylation of carbazole with acetic anhydride boron trifluoride, phosphorus pentoxide, concentrated sulfuric acid, zinc chloride, and phosphoric acid all gave 9-acetylcarbazole in moderate to good yield. 9-Acetylcarbazole can also be prepared using the Vilsmeier complex of N,N-dimethylacetamide and phosgene. ... 

The electrochemistry of Cd(II) was investigated at different electrodes (GC, polycrystalline tungsten, Pt, Ni) in a basic l-ethyl-3-methylimidazolium chloride/tet-rafluoroborate, at room temperature molten salt [312], and in acidic zinc chloride-l-ethyl-3-methylimidazolium [284]. 

Most linear ceilulosics may be dissolved in solvents capable of breaking the strong hydrogen bonds. These solvents include aqueous solutions of inorganic acids, zinc chloride, lithium chloride, dimethyl dibenzyl ammonium hydroxide, and cadmium or copper ammonia hydroxide (Schweizer s reagent). Cellulose is also soluble in hydrazine, dimethyl sulfoxide in the presence of formaldehyde, and dimethylformamide in the presence of lithium chloride. The product precipitated by the addition of nonsolvents to these solutions is highly amorphous and is called regenerated cellulose. 

Various dehydrating agents—concentrated sulphuric acid, zinc chloride, phosphorus pentoxide—can be used. Sulphuric acid, although perhaps the most convenient, has the disadvantage that it tends to sulphonate the aromatic substances employed. At a low temperature, however, diphenylmethane can be obtained from benzyl alcohol and benzene. At 140° phosphorus pentoxide condenses benzene and diphenylcarbinol to triphenylmethane (see B., 7,1204). Not only substituted benzyl alcohols, but even mandelic acid can be brought within the scope of the reaction, while in place of benzefte its nitro, amino or phenolic derivatives may be used. 

The hydrochloric acid-zinc chloride reaction may be an Sjy2 type displacement, particularly in the case of primary alcohols. 

Zinc Dil. hydrochloric acid Zinc chloride Hydrogen... 

Electrically neutral species are less easy to accommodate within fluorescent PET sensor designs, especially if they are to operate under competitive solvent conditions. Strategies to overcome this hurdle are outlined in Sect. 6. However, the Lewis acid zinc chloride was employed to modulate the fluorescence of (40) by perturbing its amine moiety seventeen years ago [97a] (64). [64] is a modem version which produces a very large fluorescence enhancement in acetonitrile for which photographic evidence is available [54b]. Irreversible interactions invol-... 

In the plant, alkylations are carried out in large horizontal or upright kettles (see chrysophenine). The alkyl chlorides are prepared from hydrochloric acid, zinc chloride (ferric chloride can be used equally well in place of zinc chloride) and alcohol, and are transported in large iron cylinders and stored in reservoirs. For use, the material is trans-... 

Under these conditions, base-sensitive substrates may undergo decomposition. To avoid this drawback, protic and Lewis acid can be utilized, such as p-toluenesulfonic acid, zinc chloride, cobalt chloride or scandium triflate. 

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