Extraction of dibenzothiophene from dodecane using ionic liquids as the extracting phase has been investigated for a range of ionic liquids with varying cation classes (imidazolium, pyridinium, and pyrrolidinium) and a range of anion types using liquid-liquid partition studies and QSPR (quantitative structure-activity relationship) analysis. The partition ratio of dibenzothiophene to the ionic liquids showed a clear variation with cation class (dimethylpyridinium . methylpyridinium . pyridinium # imidazolium # pyrrolidinium), with much less significant variation with anion type. Polyaromatic quinolinium-based ionic liquids showed even greater extraction potential, but were compromised by higher melting points. For example, 1-butyl-6-methylquinolinium bis{(trifluoromethyl)sulfonyl}amide (mp 47 uC) extracted 90% of the available dibenzothiophene from dodecane at 60 uC.

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Cigarette butts are one of the most common types of litter all around the world. This waste when disposed of in the environment pose a major threat to living organisms and ecosystem health. Cigarette butts are mainly made of cellulose acetate (2.45 substitution) that biodegrades slowly and can take up to 18 months to break down under normal litter conditions. Cellulose acetate is a valuable polymer that can be used for a great variety of applications. In this communication, we present the results from an ongoing study addressed to value cigarette butt waste based on the recovery of the cellulose acetate by a methodology that includes several solid-liquid extractions and a chemical precipitation. For that purpose three samples of cigarette butts were prepared and they were extracted with 5% (w/v) NaCl aqueous solution, 5% (w/v) NaAc aqueous solution or 0,02% (w/v) H2SO4 aqueous solution. After that, they were further extracted with absolute ethanol and diethyl ether. The cleaned butts were suspended in acetone and distilled water was added until a white precipitate of cellulose acetate was formed. Cellulose acetate was characterised by FTIR-ATR and its melting point. Extracts were analized by ICP-MS and GC-MS.

2-Aminothioisomünchnones, a well-known family of masked dipoles, react with aromatic aldehydes in a domino cascade reaction that produces episulfides (thiiranes) or beta-lactams (2-azetidinones). This sequence is initiated by a [3+2] dipolar cycloaddition followed by ring opening of cycloadducts and intramolecular rearrangement to afford these unusual ring contractions. The nature of the reaction products depends on the structural characteristics of the starting dipole and the experimental conditions. Episulfides are obtained selectively as cis isomers with respect to both aryl groups, whereas beta-lactams are produced as cis/trans mixtures. These structural features were determined unequivocally by X-ray crystallographic analysis. The beta-lactams still possessed a flexible acyclic chain containing sulfur, a salient lead modification of the bioactive cyclic penems and cephems. The preferential production of exo transition structures was rationalized with the aid of computational calculations at the B3LYP/6-31G* level.

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