Synthesis and characterization of poly-L-leucine initialized and immobilized by rehydrated hydrotalcite: understanding stability and the nature of interaction.

PLLs were synthesized by the ring-opening polycondensation (ROP) method using α-L-leucine N-carboxyanhydride (NCA) and initialized by triethylamine (Et3N), water or rehydrated hydrotalcite (HTrus). The role of temperature, different initiators and water in ROP was further investigated. In general, the initiators used in the polymerization reaction lead to PLL alpha-helical chains containing 5-40 monomers with NCA endgroups via a monomer-activated mechanism.

Biohydrogen production by dark fermentation of glycerol using Enterobacter and Citrobacter Sp.

Glycerol is an attractive substrate for biohydrogen production because, in theory, it can produce 3 mol of hydrogen per mol of glycerol. Moreover, glycerol is produced in substantial amounts as a byproduct of producing biodiesel, the demand for which has increased in recent years. Therefore, hydrogen production from glycerol was studied by dark fermentation using three strains of bacteria: namely, Enterobacter spH1, Enterobacter spH2, and Citrobacter freundii H3 and a mixture thereof (1:1:1).

Hydrogen substitutes for the in situ generation of H2O2: an application in the Fenton reaction.

This study investigates the ability of formic acid, hydrazine and hydroxylamine to act as H(2) substitutes in conducting phenol degradation by Fenton reaction using in situ generated hydrogen peroxide. The processes were performed with semi-heterogeneous (Pd/Al(2)O(3)+soluble Fe(2+)) and fully heterogeneous (FePd/Al(2)O(3)) catalytic systems under ambient conditions. In contrast to bulk H(2)O(2) production conditions, hydrazine is able to produce H(2)O(2)in situ followed by phenol degradation using Pd/Al(2)O(3)+Fe(2+) at pH 3 without the need for halide ions.

Simultaneous in situ generation of hydrogen peroxide and Fenton reaction over Pd-Fe catalysts.

High mineralization degree of organic compounds can be achieved by a novel environmentally-friendly full heterogeneous Pd-Fe catalytic system, which involves in situ generation of hydrogen peroxide from formic acid and oxygen, and oxidation of organic compounds by Fenton process in a one-pot reaction.

Aldol condensations over reconstructed Mg-Al hydrotalcites: structure-activity relationships related to the rehydration method.

Two different rehydration procedures in the liquid or gas phase have been applied to reconstruct mixed oxides derived from calcined hydrotalcite-like materials to be used as catalysts for aldol condensation reactions. The as-synthesized hydrotalcite, its decomposition product, as well as the reconstructed solids upon rehydration were characterized by XRD, N(2) adsorption, He pycnometry, FTIR, SEM, TEM, (27)Al MAS-NMR and CO(2)-TPD (TPD=temperature-programmed desorption). Compared to the Mg-Al mixed oxide rehydrated in the gas phase (HT-rg), that rehydrated in the liquid phase (HT-rl) exhibits a superior catalytic performance with respect to the aldol condensation of citral with ketones to yield pseudoionones and in the self-aldolization of acetone.

Supported choline hydroxide (ionic liquid) as heterogeneous catalyst for aldol condensation reactions.

Choline hydroxide was used as a basic catalyst for aldol condensation reactions to produce new C-C bonds between several ketones and aldehydes. Choline supported on MgO exhibits higher TOF values than other well known basic catalysts in these reactions.