G. Moraglio

SULFONATION OF POLYETHERETHERKETONE BY CHLOROSULFURIC ACID

Sulfonated poly(oxa-p-phenylene-3,3-phthalido-p-phenylene-oxa-p-phenylene-oxy-phenylene) (PEEK-WC) with various degrees of substitution was obtained by reaction of polyetheretherketone with neat chlorosulfuric acid. Highly sulfonated PEEK-WC was freely soluble in cold water. By working under suitable reaction conditions, no degradation of the polymeric chain was detected. The modified PEEK-WC was able to form asymmetric membranes. The expected chlorosulfonated derivatives were never achieved.

Chromatographic characterization of a molecularly imprinted polymer binding theophylline in aqueous buffers

Abstract A theophylline-binding polymer was prepared utilizing the technique of non-covalent molecular imprinting polymerization. The polymer obtained was packed in a high-performance liquid chromatography (HPLC) column, and the molecular recognition mechanism regulating the binding behavior was studied by frontal and zonal chromatography, determining the effects of pH and methanol on the affinity constant and concentration of the binding sites. The values of binding capacity found show thet ability of the imprinted polymer to bind theophylline in aqueous buffer, even if with reduced affinity with respect to the values reported in literature for the same polymer in an organic medium. Hydrogen bonding was confirmed as leading interaction in the recognition mechanism.

Selective and continuous-flow mono-methylation of arylacetonitriles with dimethyl carbonate under gas-liquid phase-transfer catalysis conditions

Very high selectivity in monomethylation of arylacetonitriles is observed when dimethyl carbonate is used as an alkylating agent under g.l.-p.t.c. conditions: thus phenylacetonitrile, reacting on a catalytic bed of corundum spheres coated with K2CO3 and polyethyleneglycol, yields 2-phenylpropionitrile with only 1% of bismethylated by-product. The method is a new, one-step, general route to the synthesis of 2-arylpropionitriles.

REACTIONS OF DIMETHYL CARBONATE WITH NUCLEOPHILES UNDER GAS-LIQUID PHASE-TRANSFER CATALYSIS (GL-PTC) CONDITIONS

Abstract When dimethyl carbonate (a compound that currently is being explored as an alkylating agent in place of dimethyl sulphate) is reacted in gas-liquid phase-transfer catalysis (GL-PTC) with anilines, phenols and aryl acetonitriles, only mono N -methyl anilines, methyl aryl ethers and 2-aryl propioniteriles are obtained, respectively. Methanol and carbon dioxide are the sole co-products. GL-PTC, a new method in organic synthesis, allows the reactions to be carried out over catalytic beds and under effective continuous-flow conditions.

The effect of cyclodextrins on the hydrolysis of carboxylic acid esters

Cyclodextrins and their derivatives act as inverse phase-transfer catalysts in the hydrolysis of carboxylic acid esters. The reaction is affected by temperature, choice of cyclodextrin and also by the stirring rate. Lipophilic esters are better hydrolyzed under inverse phase-transfer catalysis conditions than under classic phase-transfer catalysis (PTC) conditions. Some typical features of the reaction are emphasized and compared with classical PTC reactions.

REMOVAL OF PHENOLS FROM AQUEOUS SOLUTIONS IN THE PRESENCE OF HORSERADISH PEROXIDASE AND CYCLODEXTRIN DERIVATIVES

The hydroxylated aromatic compounds, present in the industrial waste waters, constitute a great environmental problem and many different processes, such as chemical or enzymatic oxidation, were reported in order to solve this problem. In this preliminary work we studied the influence of some cyclodextrin derivatives on the oxidation of phenols by horseradish peroxidase in presence of H2O2. We found that the cyclodextrin presence promote phenols removal from aqueous solution for a large set of compounds and we started to study the kinetic of the highly reactive 2, 4, 6-tribromophenol.

Alkyl capped carbonates ofβ-cyclodextrin

The synthesis is described of alkyl capped carbonates ofβ-cyclodextrin, obtained from diols activated with carbonyldiimidazole. The reaction preferentially gave monocapped derivatives which were characterized by HPLC, TLC, FT-IR and13C-NMR. These compounds are stable at pH <7, and methyl orange was found to form stronger inclusion compounds with cappedβ-cyclodextrin than with the parentβ-cyclodextrin. Paramagnetic Gd(III) complexes were also studied, but they were found to be included into cappedβ-cyclodextrin as well as intoβ-cyclodextrin.

Enantiomeric Separation of Dichlorprop by Capillary Electrophoresis Using β-Cyclodextrin Derivatives as Chiral Resolving Agents

In this work chemical derivatives of β-cyclodextrins (β-CD) have been considered and the inclusion constants with the racemic herbicide dichlorprop, only the (+) isomer of which being herbicidally active, have been determined. The experimental results showed that β-CD functional substituent affect both the inclusion constant values and the resolving power.

Kinetic study on exchange reaction of alkyl halides under gas–liquid phase-transfer catalysis conditions

Catalytic exchange of halogen in hydrocarbon halides can be performed continuously under gas–liquid phase-transfer catalysis conditions by feeding a solid bed, containing a ‘onium salt as phase-transfer catalyst, with the reagents. The solid support for the catalyst plays an important part in solvating the anions and so its nature affects the activity. The best support found consisted of glass spheres. The reaction does not depend on gaseous diffusion, but does require diffusion of the reagents into the catalyst liquid film. To obtain kinetic constants, experimental conversion curves were correlated with empirically calculated formulae.