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Sulfonation in general

One of the most important reactions of sulfones in general is the R amberg Backlund rearrangement, which involves the conversion of a-halosulfones to olefins with accompanying loss of hydrogen halide and sulfur dioxide under basic conditions (equation 48)151. [Pg.691]

Roger and co-workers [68] have recently extended their studies to encompass heterocyclic sulfoxides and sulfones. In general, these compounds were less potent (up to 1,000 fold) than their a-keto heterocycle congeners. The best results were obtained with the benzoxazole sulfoxide (50) with a K of 2.6/iM. [Pg.217]

Vinyl sulfones in general serve as excellent dienophiles in Diels-Alder reactions,4 and we5 and others2-4 have found the resultant cyclohexene to contain very useful functionality for further manipulation. Hence the vinyl sulfone moiety can serve as a synthon for ethylene,6 terminal olefins,7 acetylene,8 and vinylsilanes9 in [4+2]-cycloadditions as well as valuable synthetic intermediates in general.10... [Pg.171]

Benzothiazolyl anions were generated in situ (method B) or pre-formed with LDA (method A) for Pyr sulfones method A with n-butyllithium was used. High yields were obtained for some allyhc and propargylic sulfones. In general, relatively high stereochemical preferences were noted. [Pg.207]

Nonaqueous organic solvents consist of the following classes of compounds aliphatic and aromatic hydrocarbons and their halogenated and nitro derivatives, alcohols, carboxylic acids, esters, ethers, ketones, aldehydes, amines, nitriles, unsubstituted and substituted amides, sulfoxides, and sulfones. In general, a compound... [Pg.94]

Aromatic poly amine hardeners These mostly solid hardeners include metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenyl sulfone. In general, these hardeners provide poorer bond strengths and are more sensitive to temperature cycling than the aliphatic amines. Shrinkage is also high. [Pg.82]

This set the stage for the final deprotection, and Ross took charge. For years we had always isolated cationic carbapenems as chlorides, sulfates or phosphates, and in the present case none of these salts was truly satisfactory for all of our needs. Ross began to examine a series of new anions for salt formation, and discovered that aryl sulfonates in general formed excellent salts. Of these the benzenesulfonate salt proved best, affording an exquisitely crystalline and stable... [Pg.26]

The material prepared from the lower-molecular-weight fraction is commercially referred to as dodecylbenzene and the higher, as tridecylbenzene. The so-called tridecyl material is actually a mixture of mostly C12 and C14 isomers the exact mixture depends on the manufacturer. The tridecylbenzene sulfonate, in general, shows better detergent properties and better foaming in soft water, whereas dodecylbenzene sulfonate has a lower cloud point and better viscosity behavior in liquid formulations. [Pg.58]

Of these the most important are the sulfonic acids In general however sulfonic acids are not prepared by oxidation of thiols Arenesulfomc acids (ArS03H) for example are prepared by sulfonation of arenes (Section 12 4)... [Pg.650]

In general, the presence of fatty acid groups in the phosphoHpid molecule permits reactions such as saponification, hydrolysis, hydrogenation, halogenation, sulfonation, phosphorylation, elaidinization, and ozonization (6). [Pg.99]

Reactions. In general, isoquiaoline undergoes electrophilic substitution reactions at the 5-position and nucleophilic reactions at the 1-position. Nitration with mixed acids produces a 9 1 mixture of 5-nitroisoquiaoline [607-32-9] and 8-nitroisoquinoline [7473-12-3]. The ratio changes slightiy with temperature (143,144). Sulfonation of isoquiaoline gives a mixture with 5-isoquiaolinesulfonic acid [27655-40-9] as the principal product. [Pg.395]

Sulfonic acids are such strong acids that in general they can be considered greater than 99% ionized. The piC value for sulfuric acid is —2.8 as compared to the piC values of —1.92, —1.68, and —2.8 for methanesulfonic acid, ethanesulfonic acid, and benzene sulfonic acid, respectively (3). Trifluoromethanesulfonic acid [1493-13-6] has a piC of less than —2.8, making it one of the strongest acids known (4,5). Trifluoromethanesulfonic acid is also one of the most robust sulfonic acids. Heating this material to 350°C causes no thermal breakdown (6). [Pg.95]

In general, the higher the foaming power, the lower the toxicity (39). Sulfonates that are absorbed into a living system are readily distributed and excreted. [Pg.99]

Zinc chloride is a Lewis acid catalyst that promotes cellulose esterification. However, because of the large quantities required, this type of catalyst would be uneconomical for commercial use. Other compounds such as titanium alkoxides, eg, tetrabutoxytitanium (80), sulfate salts containing cadmium, aluminum, and ammonium ions (81), sulfamic acid, and ammonium sulfate (82) have been reported as catalysts for cellulose acetate production. In general, they require reaction temperatures above 50°C for complete esterification. Relatively small amounts (<0.5%) of sulfuric acid combined with phosphoric acid (83), sulfonic acids, eg, methanesulfonic, or alkyl phosphites (84) have been reported as good acetylation catalysts, especially at reaction temperatures above 90°C. [Pg.253]

Included in this grouping are D C Green No. 5 (13), a water-soluble sulfonate, D C Green No. 6 (14), an unsulfonated water-insoluble compound, and D C Violet No. 2 (29), a water-insoluble hydroxyanthraquinone. Anthraquinone color additives, in general, are light stable and have good physical and chemical properties for use in cosmetics (see Dyes, ANTHRAQUINONE). [Pg.443]

Acid—mordant dyes have characteristics similar to those of acid dyes which have a relatively low molecular weight, anionic substituents, and an affinity to polyamide fibers and mordant dyes. In general, brilliant shades caimot be obtained by acid—mordant dyes because they are used as their chromium mordant by treatment with dichromate in the course of the dyeing procedure. However, because of their excellent fastness for light and wet treatment, they are predominandy used to dye wool in heavy shades (navy blue, brown, and black). In terms of chemical constitution, most of the acid—mordant dyes are azo dyes some are triphenyhnethane dyes and very few anthraquinone dyes are used in this area. Cl Mordant Black 13 [1324-21 -6] (183) (Cl 63615) is one of the few examples of currentiy produced anthraquinone acid—mordant dyes. It is prepared by condensation of purpurin with aniline in the presence of boric acid, followed by sulfonation and finally by conversion to the sodium salt (146,147). [Pg.336]

Ester eliminations are normally one of two types, base catalyzed or pyrolytic. The usual choice for base catalyzed j5-elimination is a sulfonate ester, generally the tosylate or mesylate. The traditional conditions for elimination are treatment with refluxing collidine or other pyridine base, and rearrangement may occur. Alternative conditions include treatment with variously prepared aluminas, amide-metal halide-carbonate combinations, and recently, the use of DMSO either alone or in the presence of potassium -butoxide. [Pg.329]

In general, fluorinated sulfonic acids can be used as eatalysts for various cationic cyclizations Typical examples are the triflic acid catalysis in the double cyclization of A,VV-dibenzylpropynylamine [82] (equation 30) and the fluorosulfonic acid catalyzed condensation of phenylacetaldehyde [<5J] (equation 31)... [Pg.953]


See other pages where Sulfonation in general is mentioned: [Pg.126]    [Pg.421]    [Pg.446]    [Pg.210]    [Pg.506]    [Pg.126]    [Pg.421]    [Pg.446]    [Pg.210]    [Pg.506]    [Pg.268]    [Pg.401]    [Pg.283]    [Pg.560]    [Pg.44]    [Pg.331]    [Pg.337]    [Pg.467]    [Pg.81]    [Pg.82]    [Pg.99]    [Pg.244]    [Pg.348]    [Pg.291]    [Pg.385]    [Pg.162]    [Pg.376]    [Pg.384]    [Pg.132]    [Pg.77]    [Pg.251]    [Pg.441]   


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In general

In sulfonation

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