Halides, Nitrates and Sulfonates

The CH2OH group is ortho para directing towards electrophilic attack. Nitration and sulfonation are possible, but care must be taken to avoid interaction with the hydroxyl group. It is sometimes preferable to carry out the electrophilic substitution reaction on the appropriate benzyl halide and then to hydrolyse the product to the substituted alcohol. 

The mechanism for Friedel-Crafts alkylation, like that for halogenation, nitration, and sulfonation, involves the attack of the aromatic ring onto a strong electrophile, in this case, a carbocation formed by reaction between the alkyl halide and the Lewis acid catalyst. 

The first step is diffusion controlled while the second represents the formation of an outer sphere complex in which the metal ion and the ligand are separated by at least one molecule to water. In the final step, this outer sphere complex ejects the water and forms an inner sphere complex in which the metal and ligand are directly associated. Some ligands cannot displace the water and complexation apparently terminates with the formation of the outer sphere complex. Plutonium cations form both inner and outer sphere complexes, depending on the ligand pK. For trivalent plutonium, we can assign a predominant outer sphere character to the halide, nitrate, sulfonate and trichloroacetate complexes and an inner sphere character to the fluoride, iodate, sulfate and acetate complexes (23). A study of Am , Th and complexation... 

With most of the compounds studied, the three reactions were considered to proceed simultaneously, although methyl nitrate gave the ether exclusively, and benzyl nitrate was converted almost quantitatively into benzaldehyde. There is some similarity between nitrates, halides, and sulfonates, although, with nitrates, formation of olefins has minor impor-... 

The reactions of compounds containing one nitrate group at Cl, C2, or C6 have been compared with those of the corresponding halides and sulfonate esters. Barium carbonate in boiling methanol converts 2,3,4,6-... 

Uses. Tetramethylene sulfone has high solvent power for aromatics and has been used extensively by Olah and co-workers for Friedel-Crafts type nitrations and for studies of the mechanism of nitronium tetrafluoroborate nitration of alkyl-benzenes and halobenzenes in homogeneous solution. It is a superior solvent for quaternization of tertiary amines with alkyl halides, since it has a high dielectric constant and does not enter into side reactions observed with nitrobenzene and dimethylformamide. For example in the synthesis of the acridizinium salt (3), Bradsher and Parham effected quaternization of (1) with benzyl bromide in tetramethylene sulfone at room temperature in excellent yield. Several other salts analagous to (2) were obtained in good yield and in crystalline form with use of tetramethylene sulfone, whereas with other solvents the products were colored... 

The ion-exchange process is applicable for removing a broad range of ionic species from water containing all metallic elements, inorganic anion such as halides, sulfates, nitrates, cyanides, organic acids such as carboxylics, sulfonics, some phenols at sufficiently alkaline pH conditions, and organic amines at sufficiently acidic conditions. 

Alkyl halides are often used as substrates instead of alcohols. In such cases the salt of the inorganic acid is usually used and the mechanism is nucleophilic substitution at the carbon atom. An important example is the treatment of alkyl halides with silver nitrate to form alkyl nitrates. This is used as a test for alkyl halides. In some cases there is competition from the central atom. Thus nitrite ion is an ambident nucleophile that can give nitrites or nitro compounds (see 0-60).731 Dialkyl or aryl alkyl ethers can be cleaved with anhydrous sulfonic acids.732... 

The nitro group does not undergo migration of the naphthalene ring during the usual nitration procedures. Therefore, mono- and polynitration of naphthalene is similar to low temperature sulfonation, The nitronaphthalenes and some of their physical properties arc listed in fable 2. Many of these compounds are not accessible by direct nitration of naphthalene but are made by indirect methods, e.g nitrite displacement of diazonium halide groups in the presence of a copper catalysts, decarboxylation of nitronaphtbalcnccar-boxylic acids, or deamination of nitronaphthalene amines. They are nsed in the manufacture of chemicals, dye intermediates, and colorants for plastics. 

As a first approximation, the reactions of pyridines with electrophiles can be compared with those of trimethylamine and benzene. Thus, pyridine reacts easily at the nitrogen atom with reagents such as proton acids, Lewis acids, metal ions, and reactive halides to form salts, coordination compounds, complexes, and quaternary salts, respectively. Under much more vigorous conditions it reacts at ring carbons to form C-substitution products in nitration, sulfonation, and halogenation reactions. 

Many aliphatic and arylalkyl halides (Cl, Br, I), sulfates (OSOj"), sulfonates (OSO R), nitrates (NO ), and organo-... 

You will be provided with 8-hydroxyquinohne-5-sulfonic acid solid (225.23 g mol-1) water-soluble nitrate, sulfate, or halide salts of Ag(I), Al(III), Cd(II), Co(II), Cr(III), Cu(II), Hg(II), Mg(II), Ir(III), Ni(II), Pb(II), Pt(H), Zn(II), and hexadecyltrimethyl -ammonium chloride (HTAC) 1 cm pathlength quartz fluorescence cuvette 100-1000 pi auto-pipetter and tips 10 and 25 ml volumetric flasks 10 and 25 ml round-bottom flasks 40 four-dram sample vials with screw caps gloves wash acetone and spectroscopic-grade methanol... 

There is always a certain amount of ring-chlorinated by-product formed in the nitrations. Reactions carried out either by using an excess of aromatics as solvent (TiCU is miscible with many aromatics) or in carbon tetrachloride solution, always contain chlorinated by-products. The amount of chlorinated by-products can be decreased by using solvents with higher dielectric constants. Tetramethyiene sulfone (sulfolane) was found to be a suitable solvent for the TiCL and also for most of the other Lewis-acid-catalyzed nitrations. It has excellent solvent properties for aromatics and the catalysts as well as for nitryl halides. It is superior to other solvents that can be used, such as nitromethane. As it is completely miscible with water, the work-up of the reaction mixtures after the reactions are completed is very easy. 

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