Isobutylene sulfide

Isobutylene sulfide is prepared according to published procedures from isobutylene oxide and potassium thiocyanate.8 A 250-mL, round-bottomed flask, fitted with a magnetic stir bar and addition funnel, is charged with 97 g (1.0 mol) potassium thiocyanate and 100 mL water. With vigorous stirring, 72 g (90.0 mL, 1.0 mol) isobutylene oxidef is added dropwise over 5 h via the addition funnel. Owing to the exothermicity of the reaction, slow addition is... 

Isobutylene sulfide is a clear, colorless liquid with a boiling point of 84-86°C and a density of 0.90 g mL. The liquid has a characteristic sulfur stench. The NMR in C6D6 displays singlets at 2.15, 2H, and 1.35, 6H. During storage a white precipitate may form, but this does not seem to affect the use of isobutylene sulfide in further reactions. Storing the sample in a freezer ( —10°C) slows the rate of decomposition. 

A 100-mL Schlenk flask equipped with a magnetic stir bar and attached to an N2 line with oil bubbler for pressure release is charged with 50 mL dry benzene and 2.0 mL (1.96 g, 0.0172 mol) distilled free amine. Crude daco may be used, but leads to less pure product and lower yields. The mixture is warmed to 50-60°C under N2 and a single 3.4 mL (0.034 mol) portion of isobutylene sulfide is added. The mixture is then heated under N2 for 12 h. 

This method has been applied for the synthesis of ethylene sulfide,4 u- 2-47 propylene sulfide, a eia- and gran 2-butene sulfides,74 7 isobutylene sulfide,1 7 cyclohexene Hulfide,1 107 3-lMsethoxypropytoir. sulfide,122 and styrene sulfide.40 A modification of thie reaction ha, been used for the synthesis of carbohydrates possessing episulfidc structures.4 ... 

I) By alcohols. In the absence of acid or base catalyst, epi-sulfidee are not prone to react with alcohols. In the presence of a catalytic quantity of boron trifluoride, isobutylene sulfide react when... 

IS) By ethyl cyanoacetate. Attempted base-catalyzed condensations of ethyl malonate and ethyl acetoaoetate -with the simple episulfides have been unsuccessful. However, 2-iminothioplianes are obtainable from ethyl cyanoacetate and alkene sulfides.108 In the alkylation of ethyl cyanoacetate with propylene sulfide and isobutylene sulfide, mjcloophilic attack by the carb nion is on the primary carbon atom of the episulfide (Eq. 53). 

The direction of ring opening of unsymmeu-ica) episulftdes by thiols in the presence of either acid or base catalyst t pears to be rather non-seleotiTc. Mixtures of primary and t iaty mercaptons have been obtained by reaction of isobutylene sulfide with some o the simple aliphatio thiols such as -bntanethiol iu the presence of catalytic quantities of either boron tiifiuoride or sodium etbozide (Eq. 43). 

The thermal properties of poly(ethylene sulfide) and poly(isobutylene sulfide) and copolymers have been reported via DSC (differential scanning calorimetry) [9e]. 

Although the reactivity increase caused by crown ethers and cryptands in anionic polymerizations has already found a wide range of application, more details have been reported and a number of questions concerning the type and the behavior of the different species present, both in the initiation and in the propagation steps, have been clarified by, for example, kinetic studies [235], Special polymerization reactions that were effected in the presence of crown compounds are those starting with butadiene, propene, styrene, 2-vinyl pyridine, ethylene oxide, propylene sulfide, isobutylene sulfide, methyl methacrylate, p-propyllactone, or e-caprolactone as monomers and alkali metals as initiators [238-246],... 

Boileau, S., Polymerization of isobutylene sulfide under the influence of crown complexes, Tetrahedron Lett., 1978, 1767. 

Boileau, Kaempf, Schue and coworkers have studied the cryptate mediated anionic addition polymerization of several systems including ethylene oxide [38], propylene sulfide [39-40], isobutylene sulfide [40], isoprene [38], methyl methacrylate [38], hexamethyl trisiloxane [40], e-caprolactone [41], styrene [38, 40, 41], ct-methylstyrene [41], 1,1-diphenylethylene [41] and /3-propiolactone [42]. The polymerization of the latter compound induced by dibenzo-18-crown-6 complexed sodium acetate has also been reported [43]. In general, it was found that the polymer-... 

This rule is enough general to be applied to initiators resulting from ZnEt CdMe and CdEt as organometallic compounds and alcohols and 1,2 diols as chiral components. It is interesting to notice that in the copolymerization of racemic methylthiirane with achiral monomers such as ethylene sulfide or isobutylene sulfide, the choice is not modified this strongly substantiating the coordination interaction between the initiator and the monomer and the lack of existence of chain effect (39). 

Carbon-13 spectroscopy has been used very effectively by Corno and coworkers [115-117] to characterize the distributions of monomer sequences in copolymers derived from episulfides using anionic catalysts. Although chiral monomers were not employed in these studies, it is worth noting that tacticity effects had a relatively small effect on the resonance patterns observed, but that the chemical shifts of in-chain carbon atoms in different sequences were s ibstantially different. On the basis of assignments and empirical shift parameters developed by Corno, et al., the spectra of stereoregular ethylene sulfide-propylene sulfide copolymers and propylene sulfide-isobutylene sulfide copolymers should be readily analyzed. Studies on copolymers derived from racemic monomers indicate them to have random structures a similar result can be e3q>ected for copolymers derived from optically active monomers. 

Isobutylene sulfide Isobutylene oxide a-Methylvinylmethyl ether 1-Cyano-l,3-butadiene, 1,4-... 

Poly(thioisobutylene) Isobutylene sulfide polymer 26373-01-3 Thirane, 2,2-dimethyI-, homopolymer R (C4HgS),... 

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