Edo Lilla

Ozonolysis of α-PINENE, β-PINENE, d- and l-Turpentine Oil Studied by Chirooptical Methods; Some Implications on the Atmospheric Chemistry of Biogenic Volatile Organic Compounds

The main constituents of biogenic volatile organic compounds (BVOC) released in the atmosphere from vegetation are terpenes. The most common terpenes are α-pinene and β-pinene. These molecules react with ozone, forming oxidized derivatives which have low vapor pressure and which nucleate into secondary organic aerosol (SOA). Such aerosol-forming reactions have been simulated in the gas phase on laboratory scale with the visualization of the formation of SOA. Electronic absorption spectroscopy shows that the UV peak of pinenes at 205 nm is shifted to 225 nm during and after ozonolysis and is accompanied by a series of spectral features in the near infrared region (between 850 nm and 1100 nm). Optical rotatory dispersion (ORD) spectra were recorded on pure β(+)pinene and β(−)pinene. After ozonolysis β-pinene enantiomers are converted into nopinone enantiomers. The ORD spectra of both (−)nopinone and (+)nopinone respectively were recorded. The former showed a peak at 453 nm, an inflection point at 430 nm and a trough at 405 nm. The ORD spectrum of (−)-nopinone appears completely symmetrical to that of (+)nopinone. Thus, ORD spectroscopy can distinguish between BVOC and oxidized BVOC quite easily at least in the case of β-pinene. The ORD spectra of α-pinene enantiomers are different from those of β-pinene enantiomers and although the ORD spectra of ozonized α-pinene are not easily distinguishable from those of the primary compounds, they are completely different from those of ozonized β-pinene enantiomers. A reasonable natural model of BVOC is offered by l- and d-turpentine oil whose composition reflects that of the BVOC from conifer forests. The ORD spectra of ozonized l- and d-turpentine has permitted to distinguish between the levorotatory and dextrorotatory oxidation products and showing the ketone peak at about 367–380 nm, thus permitting in a real model to distinguish between primary BVOC (turpentine) and oxidized BVOC (or SOA) corresponding to ozonized turpentine. It has been proposed that ORD spectra in the gas phase could be used to detect chiral BVOC and oxidized chiral BVOC.

Conversions of resins and asphaltenes in porous catalysts

Abstract Resins and asphaltenes can be converted to alkenes and other products in gismondine-structured zeolites, pillared clays (PILCs) and large-pore zeotypes. Different product spectra: alkanes, alkenes, oxygenates, etc. are obtained with different catalysts. In particular, mesoporous zeotypes i.e. MCM(Fe)-41 containing framework iron gives a total bitumen conversion of >15%, opening routes to possibly useful products.

Radiation‐Induced Synthesis of Fullerene‐Silica Hybrid Nanomaterials

Abstract C60 fullerene has been radiation grafted on bare and functionalized silica surface with mercaptopropyl moieties in toluene solution. The resulting fullerene‐silica hybrid nanomaterials have been characterized by FT‐IR and solid state 13C CP‐MAS NMR spectroscopy and compared to the radiolysis products of C60 in toluene. It has been found that fullerene is grafted on silica surface but, because the radiation grafting has been conducted in toluene, fullerene results arylated from radicals derived from toluene radiolysis. The fullerene‐silica hybrid nanomaterials cannot be extracted by warm decalin, demonstrating that the fullerene cage is chemically bonded on the silica surface. The thermal behavior of fullerene‐silica hybrid nanomaterials has been studied by thermogravimetric analysis (TGA) and differential thermal analysis (DTA) in air flow.

A Comparative Study on the Reinforcing Effect of Aramide and PET Short Fibers in a Natural Rubber-Based Composite

Four types of chopped fibers have been studied as reinforcement additives in a standard natural rubber based, carbon black filled formulation. The fibers studied were aramide (2 types) and polyester (2 types). The chopped fibers were added on top of the carbon black filled rubber compound at 2, 4, and 8 phr levels. The extra reinforcing effect in the modulus, especially at low elongation, the increase in hardness, the anisotropic properties, and the stiffening effects have been studied together with the evaluation of the mechanical hysteresis in strain and in compression. The permanent set of the resulting rubber compounds have been evaluated as well. The best compromise in performances and price was found for a certain type of polyester fiber.

Pyrolysis of benzene-naphthalene mixtures: A temperature dependence study

Abstract The pyrolysis of benzene-naphthalene mixtures was carried out in the range of 450–570°C and the principal products were determined. The yields of all the products increase at higher temperatures. A measure of the rates of formation of biphenyl and 1,2′-binaphthyl indicates the occurrence of a slight difference between their activation energies. The presence of alumina in the system has been also investigated.

Thermal behaviour of poly(dimethylsiloxane) hybrid silicas prepared by radiation grafting

This paper reports our investigation regarding the thermal properties of new polymer-silica hybrid materials obtained by radiation grafting. The polymer poly(dimethylsiloxane),bis(3-aminopropyl)terminated is γ-grafted on a silica gel surface. The thermal behaviour of γ-grafted hybrid materials reveals remarkable differences compared to the thermal behaviour of physically adsorbed polymers. These differences allow us to assess the ability of γ-rays to produce a polymer chemically bonded on a silica surface. The chemical bonds formed by irradiation give to the polymer a high conformational stability confirmed by DTA analysis.

Chirality of products in acid-catalysed rearrangement of α-pinene

Protonation of (1R)-(+)-a-pinene using gaseous H3+ ions led to a racemic mixture of camphene and limonene, to partial and no racemization, in acidic solutions and in solid acids, respectively.