Using 3-sulfone

Diels-Alder reaction, 50, 37 of 1,4-diacetoxy-l,3-buta-diene, 50, 27 using 3-sulfone, 50, 47 2,6-Diethoxy-l,4-oxathiane, 52, 135... 

Two important widely used sulfonic acids are known as TwitcheU s reagents, or as in Russia, the Petrov catalysts. These reagents are based on benzene or naphthalene ( ) and (12), [3055-92-3] and [82415-39-2] respectively. The materials are typically made by the coupling of an unsaturated fatty acid with benzene or naphthalene in the presence of concentrated sulfuric acid (128). These sulfonic acids have been used extensively in the hydrolysis of fats and oils, such as beef tallow (129), coconut oil (130,131), fatty methyl esters (132), and various other fats and oils (133—135). TwitcheU reagents have also found use as acidic esterification catalysts (136) and dispersing agents (137). 

The GBR resin works well for nonionic and certain ionic polymers such as various native and derivatized starches, including sodium carboxymethylcel-lulose, methylcellulose, dextrans, carrageenans, hydroxypropyl methylcellu-lose, cellulose sulfate, and pullulans. GBR columns can be used in virtually any solvent or mixture of solvents from hexane to 1 M NaOH as long as they are miscible. Using sulfonated PDVB gels, mixtures of methanol and 0.1 M Na acetate will run many polar ionic-type polymers such as poly-2-acrylamido-2-methyl-l-propanesulfonic acid, polystyrene sulfonic acids, and poly aniline/ polystyrene sulfonic acid. Sulfonated columns can also be used with water glacial acetic acid mixtures, typically 90/10 (v/v). Polyacrylic acids run well on sulfonated gels in 0.2 M NaAc, pH 7.75. 

The so-called transdiazotizations are mechanistically related to the introduction of diazonio groups using sulfonic acid azides. An aromatic diazonium ion forms a triazene (diazoamino compound) with an aromatic amine the triazene tautomerizes and dissociates at the Na-Np bond of the original diazonium ion. This reaction is important for the synthesis of the 4-aminobiphenyl-4,-diazonium ion, which cannot be obtained by direct (mono-)diazotization of 4,4 -diaminobiphenyl (Allan and... 

The formation of halogenation products from Grignard reagents and sulfonic acid anhydrides is the result of an oxidative reaction pathway . This side-reaction can be reduced by using sulfonic acid esters, however, in these cases alkylations as well as twofold sulfonylations (cf. corresponding results with sulfonyl fluorides ) are competing (equations 64 and 65). 

Nitroalkenes can be replaced by u. i-unsaturated sulfones in the Barton-Zard pyrrole synthesis. Each method has its own merit. Nitroalkenes are more reactive than a,(3-unsaturated sulfones therefore, nitroalkenes should be used in less reactive cases. On the other hand, cyclic u.fi-unsaturated sulfones are more easily prepared than cyclic nitroalkenes pyrrole synthesis using sulfones is the method of choice in such cases, as shown in Eq. 10.41.46... 

Considerable work has been conducted on a water-soluble catalyst using sulfonated phosphine-modified rhodium. Details of this chemistry will be described in Chapter 5. The general concept (Figure 2.3) is to make the catalyst water soluble, then after product formation, decant the product. In order for the water-soluble catalyst to be effective, the alkene must dissolve in the aqueous layer. This has been demonstrated on a commercial basis using propene. The low solubility of higher alkenes in the aqueous catalyst layer has proven problematic. The desirable characteristic of the ligand, water solubility, is needed in the separation step but is a disadvantage in the reaction step. 

Solid polymer fuel cells use sulfonic acid group in polymer as an electrolyte and have an OT of 50 to 80°C. 

Enantioselectivities >90% were reported for a Ti-ebthi catalyst (Table 34.4 entry 4.1) and for some Rh-diphosphine complexes (entries 4.2-4.4). Interestingly, the highest ee-values were obtained using sulfonated diphosphines (bdppsuif) in an aqueous biphasic medium (entry 4.3). The degree of sulfonation strongly affected the enantioselectivity the Rh-mono-sulfonated bdpp gave 94% ee, compared to 65% ee with Rh-bdpp in MeOH, and almost racemic product with bis-or tris-sulfonated ligands. In addition, the activity of the mono-sulfonated cata-... 

AOS and MES are also produced using sulfonation methodologies similar to that for LAS (falling film sulfonation) although they require some additional post-treatment steps. When sulfonating a-olefins to produce AOS, a final hydrolysis step is required in order to eliminate sulfone by-products formed during the sulfonation. 

Sulfonation of n-paraffins to produce SAS is a totally different process involving ultraviolet (UV) catalysed reactors and much more complex processing steps than the standard sulfonation processes documented above. This has limited the availability and accessibility of this technology and consequently its broader use. Sulfonated paraffins are only produced in Europe in limited amounts. 

The esterification of acetic acid with ethanol using sulfonic ion-exchange resins as catalyst/selective sorbent was studied by Mazzotti et al. [164]. The authors developed a detailed mathematical model, which was able to predict correctly the system s behavior. They succeeded in obtaining 100% conversion of acetic acid in addition to a complete separation. Several other studies involving enzymatic reactions were also carried out and will be presented in more detail in the next section. 

Higuchi, E., Okamoto, K., Miyatake, K., Uchida, H., and Watanabe, M. Gas diffusion electrodes for polymer electrolyte fuel cell using sulfonated polyimide. Research on Chemical Intermediates 2006 32 533-542. 

Table 4.2 Biphasic hydrogenation of aldehydes using sulfonated phosphines [20].

Scheme 5 Xylose can be dehydrated to produce furfural. The reaction has been reported using several different catalysts including zeolites, sulfonic acid functionalized MCM-41 and immobilized heteropolyacids. The best selectivity towards furfural was achieved using zeolite H-mordenite, although at low conversion of xylose.Overall, the best yield of furfural was obtained using sulfonic acid functionalized MCM-41.

Levulinic acid and itaconic acid. Levulinic acid could also become an important intermediate chemical in the future since it can be produced by acid catalyzed dehydration-decomposition of fructose. The synthesis of diethyl levulinate was recently reported using sulfonated Starbon-400-S03H. The... 

Sorbitol. Sorbitol is the sugar alcohol obtained by reduction of glucose and it can be dehydrated to either isosorbide or to 1,4- and 2,5-sorbitan in acid or base catalyzed processes, respectively. Using sulfonic acid functionalized MCM-41 type materials lauric acid esters of isosorbide can be achieved quite selectively starting from sorbitol (>95% selectivity towards isosorbide dilaurate at 33% lauric acid conversion) in a dehydration-esterification... 

For instance, methyl tert-butyl ether (MTBE) used worldwide as an octane improver in gasoline is produced at a still growing global capacity of approx. 8 million mt/yr using sulfonated resins as catalysts (ref. 1). 

The complexes [Rh(bipy)3]3+, [RhCl2(bipy)2]+ and [Rh(OH2)2(bipy)2]3+ also catalyze reaction (70), with the latter two being most effective. Using sulfonated bipyridyl or phenanthroline derivatives, water-soluble catalysts were prepared.444... 

Tosylates and mesylates are commonly used sulfonates that you need to know for the MCAT. The sulfonate ions are very weak bases and excellent leaving groups. When tosylates and mesylates are leaving groups, the reaction may proceed via an SN1 or SN2 mechanism. 

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