Sulfuric acid sulfones, cyclic

Tnfluoroacetic anhydnde in a mixture with sulfuric acid is an efficient reagent for the sulfonylation of aromatic compounds [44] The reaction of benzene with this system in nitromethane at room temperature gives diphenyl sulfone in 61% yield Alkyl and alkoxy benzenes under similar conditions form the corresponding diaryl sulfones in almost quantitative yield, whereas yields of sulfones from deactivated arenes such as chlorobenzene are substantially lower [44] The same reagent (tnfluoroacetic anhydride-sulfunc acid) reacts with adamantane and its derivatives with formation of isomeric adamantanols, adamantanones, and cyclic sultones [45]... 

In the first step an S03 molecule is inserted into the ester binding and a mixed anhydride of the sulfuric acid (I) is formed. The anhydride is in a very fast equilibrium with its cyclic enol form (II), whose double bonding is attacked by a second molecule of sulfur trioxide in a fast electrophilic addition (III and IV). In the second slower step, the a-sulfonated anhydride is rearranged into the ester sulfonate and releases one molecule of S03, which in turn sulfonates a new molecule of the fatty acid ester. The real sulfonation agent of the acid ester is not the sulfur trioxide but the initially formed sulfonated anhydride. In their detailed analysis of the different steps and intermediates of the sulfonation reaction, Schmid et al. showed that the mechanism presented by Smith and Stirton [31] is the correct one. 

Acid flooding can be successful in formations that are dissolvable in the particular acid mixture, thus opening the pores. Hydrochloric acid is common, in a concentration of 6% to 30%, sometimes also with hydrofluoric acid and surfactants added (e.g., isononylphenol) [130,723]. The acidic environment has still another effect on surfactants. It converts the sulfonates into sulfonic acid, which has a lower interfacial tension with oil. Therefore a higher oil forcing-out efficiency than from neutral aqueous solution of sulfonates is obtained. Cyclic injection can be applied [4,494], and sulfuric acid has been described for acid treatment [25,26,1535]. Injecting additional aqueous lignosulfonate increases the efficiency of a sulfuric acid treatment [1798]. 

Procedure V. Ring Closure with Sulfuric Acid.198 For the conversion of Y-arylbutyric acids into cyclic ketones, the finely powdered acid (1 part) is added gradually with stirring to a mixture of concentrated sulfuric acid (3 volumes) and water (1 volume). After one hour s heating on the water bath the colored solution is cooled, diluted with water by pouring onto ice, and extracted with ether. The extract is washed with water, which removes traces of colored sulfonation product, then with dilute aqueous ammonia, and dried over anhydrous potassium carbonate the solvent is removed, the residue distilled under reduced pressure, and the distillate crystallized from a suitable solvent. 

Fisher [4] introduced sulfonic acid groups and tubular fullerenes onto graphitic nanotubes, using sulfuric acid in order to induce cyclic compounds to become adsorbed onto the surface. 

Carboxylic and sulfonic acid groups import acidity to organic compounds. Most carboxylic acids and sulfuric acids are readily dissolved in water, and their titration with a base is straightforward. If solubility in water is not sufficient, the acid can be dissolved in ethanol and titrated with aqueous base. Aliphatic amines and many saturated cyclic amines can be titrated directly with a solution of a strong acid. Esters are determined by saponification with a measured quantity of standard base. The excess base is titrated with standard acid. 

Both phenylacetic and 3-phenylpropionic acids (120) easily undergo the Schmidt reaction under the standard conditions using sulfuric acid, giving the corresponding amines (121). 4-Phenylbutyric acid (122), however, produces the cyclic lactam (123), in addition to the sulfonated amine (124). Replacement of sulfuric acid with polyphosphoric acid again affords the lactam (123) mainly, together with 3-phenylpropylamine (125) as a minor product. In the rearrangement of S-phenylpentanoic acid (126), only the sulfonated amine (127) is obtained, as shown in Scheme 24. 

In straight-run gasohne a variety of sulfur compounds may be present, such as hydrogen sulfide, mercaptans, sulfides, disulfides, polysulfides, and cyclic sulfides. It is also possible that sulfonic acids and alkyl sulfates can be present because of their incomplete removal after refinery treating operations. Likewise there can be a polysulfide content as a result of doctor sweetening. Alkyl sulfates, which are hydrocarbon soluble, can form through the action of sulfuric acid upon olefins. 

Undesirable side reactions often occur when concentrated sulfuric acid is used. For sensitive substances it is thus advisable to use an organic sulfonic acid such as / -toluenesulfonic acid as etherification catalyst.664 For example, ethers of cyclic enols665, 666 can be obtained by boiling the reactants with a little /7-toluenesulfonic acid in benzene while removing the resulting water in a continuous water-separator. 

Linear polysiloxane can be synthesized by both anionic and cationic polymerizations of cyclic siloxanes such as hexamethylcyclotrisiloxane (n = 3) and octamethyl cyclotetrasiloxane (n = 4). Anionic polymerization is initiated by hydroxide, alkoxides, phenolates, silanolates and siloxoano-lates. The active species in the polymerization is the silanolate anion. Cationic polymerization is initiated by strong protonic acids such as sulfuric acid, trifluoromethane sulfonic acid and trifluoro-acetic acid (equation 53). Both the anionic and the cationic species undergo backbiting reactions during polymerization, such that an equilibrium exists between linear chains and rings. ... 

In contrast to the other large cats, the urine of the cheetah, A. jubatus, is practically odorless to the human nose. An analysis of the organic material from cheetah urine showed that diglycerides, triglycerides, and free sterols are possibly present in the urine and that it contains some of the C2-C8 fatty acids [95], while aldehydes and ketones that are prominent in tiger and leopard urine [96] are absent from cheetah urine. A recent study [97] of the chemical composition of the urine of cheetah in their natural habitat and in captivity has shown that volatile hydrocarbons, aldehydes, saturated and unsaturated cyclic and acyclic ketones, carboxylic acids and short-chain ethers are compound classes represented in minute quantities by more than one member in the urine of this animal. Traces of 2-acetylfuran, acetaldehyde diethyl acetal, ethyl acetate, dimethyl sulfone, formanilide, and larger quantities of urea and elemental sulfur were also present in the urine of this animal. Sulfur was found in all the urine samples collected from male cheetah in captivity in South Africa and from wild cheetah in Namibia. Only one organosulfur compound, dimethyl disulfide, is present in the urine at such a low concentration that it is not detectable by humans [97]. 

Oxidation on the sulfur atom of pyrrolo-benzothiazepine 175 (Scheme 34, Section 2.3.1 (1994MI283)), indolo benzothiazepine (Scheme 65, Section 3.3.1.2 (1998MI139)) and pyrrolo-benzothiadiazepine (Scheme 74, Section 4.2 (1994SC2685)) proceeds smoothly with hydrogen peroxide in acetic acid or with MCPBA to afford cyclic sulfones in good yields. 

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