P-Sultone

Conditions for hydrolysis (82) of the intermediate sultone mixture also help modify the ratio of alkenesulfonate to -hydroxyalkanesulfonate, distribution of alkenesulfonate positional isomers, and completeness of conversion. Caustic hydrolysis using a slight stoichiometric excess of base is employed to ensure alkaline conditions throughout the hydrolysis phase of AOS production. The rate of hydrolysis depends a great deal on temperature. The 5-sultone requires the most time for conversion to 4-hydroxyalkanesulfonate. P-Sultones and y-sultones hydrolyze so rapidly to 2-hydroxyalkanesulfonate and 3-hydroxyalkanesulfonate that temperatures below 100°C can be used. 5-Sultone completely hydrolyzes between 120 and 175°C in 1—30 minutes. The quaUty of the final product mixture is ultimately determined by the choice of conditions. 

Perfluoroallyl fluorosulfate is prepared by the treatment oiperfluoropropene with sulfur tnoxide m the presence of boron catalysts [2, 3, 4, 5, 6, 7] (equation 2) Perfluoroisopropyl allyl ether reacts similarly to give 58% polyfluoroallyl fluorosulfate in a cis/trans ratio of 6 4 [S] Sultones are the exclusive products without catalyst. Polyfluoroolefins such as 2-hydropentafluoropropylene [9], (2,3-dichloropropyl)tri-fluoroethylene [70], perfluoropropene [2, i], perfluoroisopropyl alkenyl ethers [S], and acyclic polyfluoroallyl ethers [77] undergo sulfur trioxidation to regioselectively produce the corresponding P-sultones in high yield... 

Octafluoroisobtttylene, whose double bond has reduced electron density and limited accessibility, reacts with sulfur tnoxidg under vigorous conditions The reaction mixture contains various components including bis-oi-tnfluorometh-yldifluoroethane-P-sultone, bis(a-trifluoromethyldifluoroethane)-(i-pyrosultone, the heptafluoroisobutenyl ester of fluorosulfonic acid, and the heptafluoroiso-butenyl ester of fluoropyrosulfomc acid [73] (equation 4)... 

Sulfur tnoxide adds to 2,2 difluoroethylenesulfonyl fluoride to afford the P sultone and its rearrangement product, bis(fluorosulfonyl)acetyl fluoride Potassium fluoride acts as a base and reacts with the acetyl fluoride to eliminate the elements of hydrogen fluoride and produce bis(fluorosulfonyl)ketene [IS] (equation 6)... 

Polyfluorovinyl ethers form unstable (i-sultones with sulfur trioxide The p sultones isomerize at 25 °C to give p carbonylsulfonate esters and acids [16, 17 The reaction of sulfur trioxide with ethyl pentafluoroisopropenyl ether to furnish 2-ketopentafluoropropanesulfonic acid and ethyl 2-ketopentafluoro-propanesulfonate is an example (equation 7)... 

The formation of compound (1) has been established under well-defined laboratory conditions in such reaction mixtures [15,26-35]. Comparison of nuclear magnetic resonance (NMR) spectra of model compounds prepared by Bakker and Cerfontain [29] with those of the reaction mixture has also clearly shown the presence of (1). p-Sultones (1) have also been identified in commercial scale equipment under less well-defined conditions [21-24]. 

According to [4], the optimum conditions of the sulfonation stage are a reactor temperature of 15°C, an S03/I0 ratio of 1.08, and 2.8 vol % S03 in the gas stream. Such mild conditions lead to sulfonation mixtures consisting of 85% P-sultones (1) 10% alkenesulfonic acids (2) 5% y-sultones (3) and less than 5% unreacted olefins. The authors observe that the reaction has been completed to more than 95% at the outlet of the reactor. This means that the incomplete conversions found by earlier authors [15] must have been due to phenomena occurring after the sulfonation. Of equal importance is the observation that the reactivity of 10 toward gaseous S03 seems similar to that of AO. 

From a process point of view, the direct neutralization is clearly preferred moreover, the product quality (color) and free oil content deteriorates with aging (Table lb). The fact that the free oil and the inorganic sulfate level increase simultaneously upon aging is due to the fact that the formation of p-sultones from olefins is a reversible reaction [28], in competition with thermal rearrangement to alkenesulfonic acid and y- and 8-sultone. The effects of the reverse reaction of p-sultones are less with AOS because the rearrangement rates of AO-derived sultones are higher [29,35]. 

The preparation and identification of four types of S03-sulfonated products of linear and branched 1-alkenes (C5-C14) are described by Boyer [121]. 13C-and, to a lesser extent, -NMR spectra were used to ascertain the structures of 2-alkenesulfonic acids, p-sultones (as 2-methoxyalkanesulfonic acids), y- and 5-sultones. The mass spectra of some methyl 2-methoxyalkanesulfonates and 4-alkyl-5-sultones were also studied. Sufficiently volatile mixtures were separated by GLC after methylation of the sulfonic groups. 

The 2-chloroalkane-1, p-sultones lead to formation of 1 -alkene- 1,3-sultones by the following mechanism ... 

The only other X=Y bond involved in additions to MCP derivatives is the S=0 double bond of sulfur trioxide. Actually, the reactions of MCP (1) and BCP (3) with S03 afford exclusively the y-sultones 608 and 609 (Scheme 85) [160], formal products of [3 + 2] additions of TMM species to S=0 double bond. However, by analogy with larger methylene- and cycloalkylidenecycloalkane derivatives which give stable P-sultones at low temperature, it is presumed that... 

P-parinaric acid, physical properties, 5 33t P-pentenoic acid, physical properties, 5 3 It P-peroxylactones, 18 484 Beta phase titanium, 24 838 in alloys, 24 854-856 properties of, 24 840, 941 P-phellandrene, 24 493 P-picoline, 21 110 from acrolein, 1 276 uses for, 21 120 P-pinene, 3 230 24 496-497 major products from, 24 478 /-menthol from, 24 522 as natural precursor for aroma chemicals, 3 232 terpenoids from, 24 478-479 P-propiolactone, polymerization of, 14 259 P-quartz solid solution, 12 637—638 Beta ratio, in filtration, 11 329—330 Beta (P) rays, 21 285 P-scission reactions, 14 280-281 P-skytanthine, 2 101 P-spodumene solid solution, 12 638-639 P-sulfur trioxide, 23 756 P-sultones, 23 527 P-tocopherol, 25 793 P-tocotrienol, 25 793 P-vinylacrylic acid, physical properties, 5 33t... 

Much research has been done on the synthesis of perhalogenated P-sultones. The sulfonation of acyclic fluorovinyl ethers leads to a product that is stable up to slightly above room temperature. Thermolysis decomposes the ring structure under SO2 evolution and formation of acid fluorides and perfluorocyclopropane (Eq. 78). )S-Sultones have been synthesized by addition of sulfonyl chlorides to perhalogenated ketones in the presence of triethylamine. The formation of the l-oxa-2-thiacyclobutane 2,2-dioxides appears to require an activated but sterically unhindered carbonyl group because acetone, chloroacetone, trifluoroacetophenone, and p-nitroaceto-phenone did not yield the desired products. ... 

Later it was found that the result of reaction of unsaturated compounds with S03 strongly depends on the structure of fluoroolefin. While HFP gives p-sultone in a high yield under the action of pure S03 [173], perfluoroallylbenzene reacts with S03 exothermally to give a mixture of /1-sultone and F-phenyl-propenyl fluorosulfate, but 3,3,3-trifluorotrichloropropene-l or 2,3-dichloro-F-butene-2 reacts with S03, forming allyl fluorosulfates 87 or 88 [175,176] ... 

Two novel reagents for the selective sulfonation of styrene to the (3-sultone (49) are reported (94ZOR948). The action of sulfur trioxide on the olefin CF2 CFS03SiMe3, yields the p-sultone (50) (94JFC89). 

Sulfenes often undergo a [2 + 2] cycloaddition reaction with halocarbonyl compounds thus, chloral (130) adds to sulfene (75) to give the p-sultone (131) (Scheme 79). 

The formation of the sultone (160) probably involves addition of the complex across the alkene double bond, a 1,2-hydride shift and an intramolecular nucleophilic substitution reaction. The sultone (161) is formed by addition of sulfur trioxide to give the unstable p-sultone which rearranges to the more stable y-isomer (161). Another useful route to sultones is by metallation of alkanesulfonate esters for example, butane-1,3-dimethylsulfonate (162), prepared from butanel,3-diol, yields the 8-sultone, namely 6-methyl-l,2-oxathiin-2,2-dioxide (163) (Scheme 67). 

Generally, sulfur trioxide reacts with hydrocarbon olefins quite vigorously and has to be either diluted or used in complexes with pyridine or dioxane to moderate its reactivity. The corresponding cycloadducts, p-sultones, easily undergo ring opening and have not yet been isolated. In sharp contrast, fluorinated p-sultones are relatively stable materials and over 50 compounds of this type have been prepared and isolated. Synthesis and chemistry of this class of heterocycles is well documented and has been previously reviewed. ... 

The original reports on synthesis of fluorinated p-sultones appeared from three different groups at approximately the same time in late 1950s.Addition of freshly distilled sulfur trioxide to TFE, chlorotrifluoroethylene, hexafluoropropylene, and... 

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