Synthesis and polymerisation of α,ω-bis(3-pyrrolyl)alkanes

The synthesis, characterisation and polymerisation studies of a homologous series of α,ω-bis(pyrrolyl)alkanes are described. These α,ω-bis(pyrrolyl)alkanes were produced using Friedel–Crafts acylation followed by reduction of the carbonyl group using Red-Al®. Chemical polymerisation of the resultant dimers using FeCl₃ produced poly(α,ω-bis(pyrrolyl)alkane) films, which were characterised by SEM, FTIR and tested for conductivity.

Structuring in liquid alkanes between solid surfaces : force measurements and mean-field theory

Measurements have been made of the solvation forces between mica surfaces in the even-numbered n-alkanes from hexane to hexadecane. In all cases the force law is qualitatively very similar, characterized by a decaying oscillatory function of distance, as occurs for simple isotropic liquids. The spacing between successive minima in the force does not increase with carbon number, and is comparable to the width of a linear alkane molecule rather than its length or any average diameter. This suggests that the alkanes have some tendency towards a parallel orientation near the mica surfaces. The measurements give no indication of any strong repulsive component expected from mean-field theories of higher alkanes or polymers. The results of one such theory are presented, and the reasons for its failure to match the experimental data are discussed.

Synthesis of ethyl acetate employing celite-immobilized lipase of Bacillus cereus MTCC 8372

A wide range of fatty acid esters can be synthesized by esterification and transesterification reactions catalyzed by lipases in non-aqueous systems. In the present study, immobilization of a purified alkaline extra-cellular lipase of Bacillus cereus MTCC 8372 by adsorption on diatomaceous earth (celite) for synthesis of ethyl acetate via transesterification route was investigated. B. cereus lipase was deposited on celite (77% protein binding efficiency) by direct binding from aqueous solution. Immobilized lipase was used to synthesis of ethyl acetate from vinyl acetate and ethanol in n -nonane. Various reaction conditions, such as biocatalyst concentration, substrates concentration, choices of solvents ( n -alkanes), incubation time, temperature, molecular sieves (3Å × 1.5 mm), and water activity(a _w ), were optimized. The immobilized lipase (25 mg/ml) was used to perform transesterification in n -alkane(s) that resulted in approximately 73.7 mM of ethyl acetate at 55 °C in n -nonane under shaking (160 rpm) after 15 h, when vinyl acetate and ethanol were used in a equimolar ratio (100 mM each). Addition of molecular sieves (3Å × 1.5 mm) as well as effect of water activity of saturated salt solutions (KI, KCl and KNO ₃ ) to the transesterification efficiency has inhibitory effect. Batch operational stability tests indicated that immobilized lipase had retained 50% of its original catalytic activity after four consecutive batches of 15 h each.

Elemental and molecular profiling of licit, illicit, and niche tobacco

The recognition of differences between regulated large-scale mass manufactured products and the uncontrolled cultivation of tobaccos for illicit purposes plays a significant role within identification of provenance. This research highlights X-ray fluorescence and Fourier transform infrared spectroscopy as useful analytical techniques for the rapid identification of tobacco samples of unknown provenance. Identification of key discriminative features within each technique allowed for the development of typical characteristic profiles for each type of tobacco. Analysis using X-ray fluorescence highlights chlorine, potassium, calcium and iron as key elemental indicators of tobacco provenance. Significant levels of chlorine seen within Snüs samples prompted attempts to visualise chlorine containing regions and structures within the sample. Scanning electron microscopy images showed crystalline structures visible within the Snüs tobacco, structures which Energy dispersive X-ray spectroscopy qualitatively confirmed to contain chlorine. Chloride levels within Snüs samples were quantified using ion chromatography with levels found to range between 0.87mgmL‾¹ and 1.28mg. Additionally, FTIR indicated that absorbances attributed to carbonyl stretching at 1050-1150cm‾¹, alkane bending at 1350-1480cm‾¹and amide I stretching at 1600-1700cm‾¹ highlighting a spectral fingerprint region that allowed for the clear differentiation between different types of tobaccos using PCA analysis, but was limited by differentiation between provenance of cigarettes and hand rolled tobacco. X-ray fluorescence and Fourier transform infrared spectroscopy yielded different information with regards tobacco discrimination and provenance, however both methods overall analysis time and cost reduced indicating usefulness as potential handheld analytical techniques in the field.