Carmine Capacchione

Novel iron(III) catalyst for the efficient and selective coupling of carbon dioxide and epoxides to form cyclic carbonates

“Re-cycling carbon dioxide with iron”. The synthesis of cyclic organic carbonates in high yield, stereo- and chemo-selectivity was accomplished through the coupling of carbon dioxide and epoxides, catalysed by a novel air-stable and easy-to-handle thioether-triphenolate iron(III) complex.

Polymerization of ethylene in the presence of 1,3-dimethoxy-p-But-calix[4]arene titanium dichloride. NMR evidence of the cationic titanium compound generated by methylalumoxane

Abstract In this paper we present, for the first time, the NMR investigation of the solution structure of the alkyl cationic titanium compound produced by reaction of 1,3-dimethoxy-p-But-calix[4]arene titanium dichloride and methylaluminoxane in the required conditions of ethylene polymerization. The role the methylalumoxane plays in the reaction with titanium compound is analyzed by NMR.

Poly(lactide-co-ε-caprolactone) copolymers prepared using bis-thioetherphenolate group 4 metal complexes: synthesis, characterization and morphology

Titanium and zirconium complexes 1–3 (1 = (t-BuOS)2Ti(O-i-Pr)2; 2 = (t-BuOS)2Zr(O-t-Bu)2; 3 = (CumOS)2Zr(O-t-Bu)2) supported by two phenolate bidentate ligands (t-BuOS-H = 4,6-di-tert-butyl-2-phenylsulfanylphenol and CumOS-H = 4,6-di-cumyl-2-phenylsulfanylphenol) promoted the copolymerization of L-lactide with e-caprolactone. The reactivity displayed by the two monomers during the copolymerization experiments and the microstructure disclosed by 13C NMR analysis indicated a gradient distribution of the two monomers along the polymer chain. Copolymers with high e-caprolactone content showed a large scale formation of crystalline spherulites prone to perfection of the crystallinity upon thermal annealing at 50 °C. Differently L-lactide rich copolymers revealed a thin film morphology consisting of small rigid domains of L-lactide segments of about 15 nm embedded in a soft matrix of the counterpart. Copolymers with comparable mole fractions of the two monomers were entirely amorphous.

A simplified early stage assessment of process intensification: glycidol as a value-added product from epichlorohydrin industry wastes

The present work deals with the production of glycidol through a new synthetic approach based on the conversion of 2-chloro-1,3-propanediol (β-MCH), a by-product in the epichlorohydrin production plant. β-MCH was converted with high yield (90%) and selectivity (99%) to glycidol using an alcoholic solution of KOH at room temperature in only 30 minutes. A simplified early stage assessment based on the use of the green metrics and a life cycle analysis were adopted in order to evaluate the environmental feasibility of this innovative route if compared with the traditional chain to epichlorohydrin. The waste recovery and the maximization of the overall process efficiency lead to sensible reductions per each indicator considered in the assessment, suggesting the possibility of developing on a full industrial scale. In addition, in order to verify the potentialities behind the substitution of the fossil-based glycidol with the product resulted from the recovery of the β-MCH, a cradle-to-gate analysis and the GREENMOTION® tool were adopted.

New zinc complexes bearing kappa2-heteroscorpionate ligands: influence of second-sphere bonding interactions on reactivity and properties.

New zinc complexes (LOMe)ZnCl(2) (1) and (LOH)ZnCl(2)(2) of the heteroscorpionate ligands 1-[(3,5-di-tert-butyl-2-methoxyphenyl)(3,5-dimethyl-pyrazol-1-yl)methyl)]-3,5-dimethyl-pyrazole (LOMe) and 2,4-di-tert-butyl-6-[bis(3,5-dimethyl-pyrazol-1-yl)methyl]phenol (LOH) have been synthesized. The X-ray molecular structure of 2 was reported and compared with the one of the iron(II) complex (LOH)FeI(2) (3). The complexes 2-3 adopt a tetrahedral structure in the solid state in which the LOH ligand is kappa(2)-coordinated to the metal via the imino nitrogens of the two pyrazolyl rings. The hydroxyl phenyl group is not coordinated to the metal but found to be involved in an intermolecular hydrogen bond. The solution structures of 1 and 2 are consistent with this tetrahedral C(S) symmetric geometry. Dilution and (1)H-(1)H Nuclear Overhauser Effect Spectroscopy (NOESY) experiments revealed that the free ligands LOMe and LOH are involved in intra- and intermolecular hydrogen bonding interactions. Coordination of LOMe and LOH to ZnCl(2) was investigated by NMR titration methods. Association constants (K(a)) of (8.6 +/- 0.4) x 10(2) M(-1) and (7.8 +/- 0.3) x 10(2) M(-1) were obtained in methanol/water solutions (95:5) for LOMe and LOH, respectively. Coordination of bis(3,5-dimethyl-pyrazol-1-yl)methane (bpm) ligand to ZnCl(2) is weaker, as evidenced by the lower value of the association constant (5.3 +/- 0.3) x 10(2) M(-1). When bpm was added to solutions of 1 or 2, an equilibrium shifted toward the (bmp)ZnCl(2) species was observed. The thermodynamic parameters for this reaction were determined by VT NMR analysis. The optical properties of the ligands (LOMe, LOH) and of the corresponding zinc complexes 1 and 2 were also investigated by means of UV-vis and fluorescence spectroscopy to assess the potential use of these ligands as fluorescent sensors for Zn(2+) detection.

Glycidol: an Hydroxyl-Containing Epoxide Playing the Double Role of Substrate and Catalyst for CO2 Cycloaddition Reactions.

Glycidol is converted into glycerol carbonate (GC) by coupling with CO2 in the presence of tetrabutylammonium bromide (TBAB) under mild reaction conditions (T=60 °C, PCO2 =1 MPa) in excellent yields (99 %) and short reaction time (t=3 h). The unusual reactivity of this substrate compared to other epoxides, such as propylene oxide, under the same reaction conditions is clearly related to the presence of a hydroxyl functionality on the oxirane ring. Density functional theory calculations (DFT) supported by 1 H NMR experiments reveal that the unique behavior of this substrate is a result of the formation of intermolecular hydrogen bonds into a dimeric structure, activating this molecule to nucleophilic attack, and allowing the formation of GC. Furthermore, the glycidol/TBAB catalytic system acts as an efficient organocatalyst for the cycloaddition of CO2 to various oxiranes.

Synthesis and physical properties of elastomeric polypropylene obtained in the presence of TiCl2(2-OC6H4OCH3)2 and methylaluminoxane

Abstract In this work we present a new synthetic route to obtain elastomeric polypropylene with high molecular weight and narrow molecular weight distribution, in the presence of TiCl 2 (2-OC 6 H 4 OCH 3 ) 2 and methylaluminoxane catalytic system. Moreover we focused on investigating the thermal, mechanical and rheological properties of the ELPP and its solvent fractions. The results demonstrate that the polymers exhibit high ultimate extension and excellent elastic recovery, due to the presence of microcrystalline domains dispersed in the amorphous phase. The elastic and viscous response has been found to depend upon the molecular weight, which changes with the polymerization temperature.

Glycidol, a Valuable Substrate for the Synthesis of Monoalkyl Glyceryl Ethers: A Simplified Life Cycle Approach

The disposal of any waste by recovering it within the production plant represents the ultimate goal of every biorefinery. In this scenario, the selective preparation of monoalkyl glyceryl ethers (MAGEs) starting from glycidol, obtained as byproduct in the epichlorohydrin production plant, represents a very promising strategy. Here, we report the synthesis of MAGEs through the reaction of glycidol with alcohols catalyzed by a green homogeneous Lewis acids catalyst, such as BiIII triflate, under very mild reaction conditions. To evaluate the green potential of the proposed alternative, a simplified life cycle assessment (LCA) approach was followed by comparing the environmental performance of the proposed innovative route to prepare MAGEs with that of the most investigated pathway from glycerol. A considerable reduction of all impact categories considered was observed in our experimental conditions, suggesting that the glycidol-to-MAGEs route can be a valuable integration to the glycerol-to-MAGEs chain. Thanks to the use of primary data within the LCA model, the results achieved are a very good approximation of the real case.

Rational design of nanoparticle/monomer interfaces: a combined computational and experimental study of in situ polymerization of silica based nanocomposites

Interfaces between methylmethacrylate monomers, oligomers and silica nanoparticles (NPs) were explored by molecular dynamics simulations, infrared and solid state nuclear magnetic resonance spectroscopy. This knowledge allowed the control of the structure of the interfaces by employment of MMA macromonomers, and the design of an improved process for in situ polymerizations with a remarkable increase of NP dispersion.

Synthesis of Monoalkyl Glyceryl Ethers by Ring Opening of Glycidol with Alcohols in the Presence of Lewis Acids

The present work deals with the production of monoalkyl glyceryl ethers (MAGEs) through a new reaction pathway based on the reaction of glycidol and alcohols catalyzed by Lewis acid-based catalysts. Glycidol is quantitatively converted with high selectivity (99 %) into MAGEs under very mild reaction conditions (80 °C and 0.01 mol % catalyst loading) in only 1 h using Al(OTf)3 or Bi(OTf)3 as catalyst. The proposed method enhances the choice of possible green synthetic approaches for the production of value-added products such as MAGEs.