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Sulfonate esters => alkenes

PHOSPHORANES and the Wittig reaction 16-43 SULFONATE ESTERS alkenes + sulfonic acids 15-06... [Pg.1934]

The direct reaction of 1-alkenes with strong sulfonating agents leads to surface-active anionic mixtures containing both alkenesulfonates and hydroxyalkane sulfonates as major products, together with small amounts of disulfonate components, unreacted material, and miscellaneous minor products (alkanes, branched or internal alkenes, secondary alcohols, sulfonate esters, and sultones). Collectively this final process mixture is called a-olefinsulfonate (AOS). The relative proportions of these components are known to be an important determinant of the physical and chemical properties of the surfactant [2]. [Pg.430]

Impurities consist of unreacted material, including alkanes and internal or branched alkenes, and other material which can be detected in the neutral oil fraction of AOS. Examination of this fraction also indicates the amount of unhydrolyzed material (sulfonate esters and sultones) and byproducts (secondary alcohols, unsaturated and 2-chloro-y-sultones) in the sample. Salt calculations are made to determine inorganic sulfates and sodium chloride. Determinations for alkalinity, color, and water are required to meet product... [Pg.430]

Neutral oil consists of unreacted alkenes, alkanes, secondary alcohol byproducts, sulfonate esters, and sultones. Calculation of the concentration of neutral oil present in AOS, taken together with separate determinations for alkenes and alcohols (see below) and nonvolatile material (determined by residue on evaporation), can be used as a measure of the completeness of the sulfona-tion reaction. [Pg.440]

Two types of sulfonate esters can be formed in the production of AOS. Neutral esters are formed by the addition of alkenesulfonic acid to alkene (Fig. 29). Acid esters are formed by the dimerization of two alkene mono- or disulfonic acids (Fig. 30). These would normally be expected to hydrolyze in the saponification stage of the process. [Pg.443]

The amount of residual sulfonate ester remaining after hydrolysis can be determined by a procedure proposed by Martinsson and Nilsson [129], similar to that used to determine total residual saponifiables in neutral oils. Neutrals, including alkanes, alkenes, secondary alcohols, and sultones, as well as the sulfonate esters in the AOS, are isolated by extraction from an aqueous alcoholic solution with petroleum ether. The sulfonate esters are separated from the sultones by chromatography on a silica gel column. Each eluent fraction is subjected to saponification and measured as active matter by MBAS determination measuring the extinction of the trichloromethane solution at 642 nra. (a) Sultones. Connor et al. [130] first reported, in 1975, a very small amount of skin sensitizer, l-unsaturated-l,3-sultone, and 2-chloroalkane-l,3-sultone in the anionic surfactant produced by the sulfation of ethoxylated fatty alcohol. These compounds can also be found in some AOS products consequently, methods of detection are essential. [Pg.444]

Sulfonesand sulfonic esters can also be alkylated in the a position if strong enough bases are used. Alkylation at the a position of selenoxides allows the formation of alkenes, since selenoxides easily undergo elimination (17-11). [Pg.555]

Trialkylboranes react rapidly and in high yields with a-halo ketones,a-halo esters, a-halo nitriles, and a-halo sulfonyl derivatives (sulfones, sulfonic esters, sulfonamides) in the presence of a base to give, respectively, alkylated ketones, esters, nitriles, and sulfonyl derivatives. Potassium tert-butoxide is often a suitable base, but potassium 2,6-di-tert-butylphenoxide at 0°C in THF gives better results in most cases, possibly because the large bulk of the two tert-buXy groups prevents the base from coordinating with the R3B. The trialkylboranes are prepared by treatment of 3 mol of an alkene with 1 mol of BH3 (15-16). With appropriate boranes, the R group transferred to a-halo ketones, nitriles, and esters can be vinylic, or (for a-halo ketones and esters) aryl. " °... [Pg.560]

Trifluoromethanesulfonates of alkyl and allylic alcohols can be prepared by reaction with trifluoromethanesulfonic anhydride in halogenated solvents in the presence of pyridine.3 Since the preparation of sulfonate esters does not disturb the C—O bond, problems of rearrangement or racemization do not arise in the ester formation step. However, sensitive sulfonate esters, such as allylic systems, may be subject to reversible ionization reactions, so appropriate precautions must be taken to ensure structural and stereochemical integrity. Tertiary alkyl sulfonates are neither as easily prepared nor as stable as those from primary and secondary alcohols. Under the standard preparative conditions, tertiary alcohols are likely to be converted to the corresponding alkene. [Pg.216]

Nucleophilic displacement using [ F] fluoride works well in aUphatic systems where reactive haUdes or sulfonates esters can undergo substitution at unhindered sites. In order to introduce a F fluorine atom in a secondary or tertiary position, a two steps strategy was developed. It involves a F-bromofluorination of alkenes, followed by reductive debromination (n-BujSnH, AIBN). [ F]BrF is usually generated in situ from [ F]potassium fluoride and l,3-dibromo-5,5-dimethylhydantoin (DBH) in sulfuric acid. This methodology was successfully applied to label steroids at the 11 and 6a positions [245] (Scheme 60) and to prepare [ F]fluorocyclohexanes [246]. [Pg.246]

The cyclopropanation of alkenes using zinc carbenoids displays excellent chemoselec-tivities. A large number of functional groups are compatible with these reagents, such as alkynes, silanes, stannanes, germanes, alcohols, ethers, sulfonate esters, aldehydes. [Pg.255]

Wc-Diols can also be deoxygenated indirectly, through sulfonate ester derivatives. For example, vic-dimesylates and Wc-ditosylates have been converted to alkenes by treatment, respectively, with naphthalene-sodium271 and with Nal in dimethylformamide.272 In another procedure, the diols are converted to bisdithiocarbonates (bis xanthates), which undergo... [Pg.1028]

The photodecomposition of aryl diazonium ions (Scheme 1) or aryl halides (Scheme 2) or sulfonate esters with electron-donating substituents gives aryl cations that can react in polar media with alkenes, forming C-C bonds in SnI reactions.1 An extensive review of the SN reactions forming C-C bonds has been published.2... [Pg.213]

If the sulfur-based anion-stabilizing group is at a higher oxidation level, it is not usually necessary to provide chelating groups to ensure reaction next to sulfur. The allylic sulfone we made earlier in the chapter (p. 1250) reacts in this wayVith an unsaturated ester to give a cyclopropane. Notice how much weaker a base (MeO-) is needed here, as the anion (and it is an anion if the counterion is Na+ or K+) is stabilized by sulfone and alkene. [Pg.1257]

The sulfonyl halides (ArSOjCl) convert the alcohol into a sulfonate (ArSOjOR), which is a better leaving group than the hydroxyl group. This allows a range of nucleophilic substitutions to be carried out, many of which parallel those found with alkyl halides. Alkyl halides such as iodides are formed by the nucleophilic substitution of the sulfonate by an iodide ion. The reaction in this case proceeds with inversion of configuration. Treatment of the sulfonate esters with bases such as sodium methoxide or collidine (2,4,6-trimethylpyridine), or even just heating them, can lead to the elimination of toluene-4-sulfonic acid and the formation of an alkene. [Pg.40]

It has already been noted that a number of derivatives of alcohols, such as the sulfonate esters, when heated in the presence of a base, such as pyridine, collidine or even alumina, undergo elimination rather than substitution, so forming an alkene. [Pg.42]

SnCLrinduced cyclizations between alkenes and enol acetates result in cycloalkanes or bicycloalkanes in high yield (Eq. 59). It is interesting to note that the MesSiOTf-catalyzed reaction can yield fused rather than bicyelo products. Alkenic carboxylic esters, allylic alcohols, sulfones, and sulfonate esters are also cyclized in the presence of SnCU alkenic oxiranes, however, often cyclize in poor yield [89a]. [Pg.419]


See other pages where Sulfonate esters => alkenes is mentioned: [Pg.442]    [Pg.443]    [Pg.1340]    [Pg.185]    [Pg.220]    [Pg.392]    [Pg.376]    [Pg.908]    [Pg.528]    [Pg.9]    [Pg.546]    [Pg.977]    [Pg.644]    [Pg.1535]    [Pg.1911]    [Pg.340]    [Pg.634]    [Pg.687]    [Pg.1193]   
See also in sourсe #XX -- [ Pg.72 ]




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Alkene sulfonates

Sulfonate esters

Sulfonic esters

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