The production of elemental sulfur from petroleum refining has created atechnological opportunity to increase the valorization of elemental sulfur by the creation of highperformance sulfur based plastics with improved thermomechanical properties,elasticity and flame retardancy.W ereport on asynthetic polymerization methodology to prepare the first example of sulfur based segmented multi-block polyurethanes (SPUs) and thermoplastic elastomers that incorporate an appreciable amount of sulfur into the final target material. This approach applied both the inverse vulcanization of S 8 with olefinic alcohols and dynamic covalent polymerizations with dienes to prepare sulfur polyols and terpolyols that were used in polymerizations with aromatic diisocyanates and short chain diols.Using these methods,anew class of high molecular weight, soluble blockcopolymer polyurethanes were prepared as confirmed by SizeE xclusion Chromatography,N MR spectroscopy, thermal analysis,a nd microscopic imaging. These sulfur-based polyurethanes were readily solution processed into large area free standing films where both the tensile strength and elasticity of these materials were controlled by variation of the sulfur polyol composition. SPUs with both high tensile strength (13-24 MPa) and ductility (348 %strain at break) were prepared, along with SPU thermoplastic elastomers (578 %s train at break) which are comparable values to classical thermoplastic polyurethanes (TPUs). The incorporation of sulfur into these polyurethanes enhanced flame retardancy in comparison to classical TPUs,w hich points to the opportunity to impart new properties to polymeric materials as ac onsequence of using elemental sulfur.

Hydrolysis and subsequent degradation of microcrystalline cellulose in five ionic liquids (ILs) using metal salts and/or Brønsted acids as catalysts allowed for the direct access to 5-hydroxymethylfurfural (HMF), an important renewable biofuel precursor and a useful building block. For each catalytic system, several reaction parameters (temperature, reaction time, catalyst, and cellulose loading) have been selectively changed. Four systems ([BMIM]­Cl-CrCl3, [BMIM]­Cl-FeCl3, [BMIM]­Cl-[MIMC4SO3H]­[HSO4] and the not yet investigated [BMIM]­Cl-TiOSO4) were found to be effective for cellulose degradation into HMF. The extraction of HMF from the reaction media represents however the weak point of all these processes being able to affect negatively both HMF recovery and IL recyclability. The critical step which causes the drastic decrease in HMF yield starting from the first recycle has been clearly identified. Furthermore, the possibility to use TiOSO4 as a sustainable and robust catalyst for the conversion of saccharides (or polysaccharides) in HMF has been shown. The present study could open new perspectives for the one-pot synthesis of HMF starting from cellulose and/or other sugars.

An investigation of the copolymerization of cyclohexene sulfide and carbon disulfide using salphen and salen Cr complexes as catalysts and [PPN]+X– salts as cocatalysts, at different temperatures and reaction times, is reported. Both catalytic systems produce both polymer and cyclic products. For the first time, poly­(trithiocyclohexylcarbonates) (PCS) have been synthetized in high yields and high molecular weights. Salphen-based catalysts, in comparison with salen-based ones, show higher productivity and selectivity for polymers with high molecular weight up to 18 kg/mol when the reaction is carried out at 25 °C. At a higher temperature with (salphen)­CrCl, the maximum value of selectivity for copolymers (72%) was obtained at a short reaction time (3 h). At long reaction times, great amounts of cyclic by-product are observed, thus evidencing the tendency for cyclohexene sulfide and CS2 to provide cyclic products due to the stability of the trithiocyclohexylcarbonate. PCS possesses high refractive index (n > 1.72), and antimicrobial assays reveal that these materials are active against Escherichia coli and moderately active against Staphylococcus aureus. These properties along with the T g values of 80 °C make these polymers suitable for interesting applications different from those of poly­(trithiopropylencarbonate).

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The single step conversion of cellulose into levulinic acid has been studied under hydrothermal conditions with several catalytic systems.

Polythionic acids, whose general formula is H 2 S n O 6 , with n greater than 2, were discovered in the aqueous solution of SO 2 and H 2 S, known as the Wackenroder liquid. Their reactions with each other and with other reagents are, mostly, difficult to characterize, since such compounds readily decompose and interconvert, especially in solution. Nevertheless, they play an important role in technical applications (e.g., gold leaching, magnesium milling, cooling in metal processing) and in reactions of inorganic chemistry of sulfur. A few years ago, Shell−Paques/ Paqell patented the first industrial process for the biological conversion of H 2 S into a colloidal mixture of sulfur and polythionates. Such hydrophilic sulfur can be used as a fertilizer and soil improver in agriculture in all but alkaline soils. Recently, Eni S.p.A. has developed to bench plant scale a new process, the HydroClaus process for the conversion of H 2 S into an acidic hydrophilic slurry of sulfur and polythionate ions. Such a slurry can be used as a soil improver where the very alkaline soil pH hinders the cultivation. The aim of this work is to study the laboratory-scale production of polythionates in view of the novel HydroClaus process scale-up at the industrial level. After the literature related to polythionates and their characterization has been revised, the sulfur-based mixture has been synthesized and the polythionate ions concentration has been determined. Also, the effect of the reaction operating conditions has been investigated to assess how they can influence the nature and the distribution of products in solution.

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