Molecular Distillation of Lavender Supercritical Extracts: Physicochemical and Antimicrobial Characterization of Feedstocks and Assessment of Distillates Enriched with Oxygenated Fragrance Components

Lavandula angustifolia is one of the most widely cultivated non-food crops used in the production of essential oil; it is used in perfumery, aromatherapy, pharmaceutical preparations, and food ingredients. In this study, supercritical fluid extraction (SFE) and molecular distillation (MD) were combined, primarily to enrich scCO₂ extracts with lavender oxygenated monoterpenes, avoiding thermal degradation, hydrolysis, and solvent contamination, and maintaining the natural characteristics of the obtained oils. Molecular distillation was developed for the first time for the extraction of crucial lavender fragrance ingredients, i.e., from two scCO₂ extracts obtained from dry flower stems of lavender cultivated in Poland and Bulgaria. The best results for high-quality distillates were obtained at 85 °C (EVT) and confirmed that linalyl acetate content increased from 51.54 mg/g (initial Bulgarian lavender extract, L-Bg-E) and 89.53 mg/g (initial Polish lavender extract, L-Pl-E) to 118.41 and 185.42 mg/g, respectively, corresponding to increases of 2.3 and 2.1 times in both distillate streams, respectively. The distillates, light oils, and extracts from lavender were also evaluated for their antimicrobial properties by determining the minimum inhibitory concentration (MIC) by the broth microdilution method. Generally, Gram-positive bacteria and Candida spp. were more sensitive to all distilled fractions and extracts than Escherichia coli (Gram-negative bacteria).     

Separation and spectrophotometric determination of trace elements in high-purity cadmium

Zusammenfassung Die Spurenanalyse zur Bestimmung von Ag, Al, Bi, Co, Cu, Ga, Hg, In, Mn, Ni, Pb, Tl und Zn in reinstem Cadmium wurde ausgearbeitet. Nach dem vorgeschlagenen Schema werden einzelne Gruppen von Spurenelementen durch Extraktion bzw. Mitfällung getrennt und spektrophotometrisch mit Hilfe der folgenden organischen Reagenzien bestimmt: Dithizon, PAN, PAR, Rhodamin B, Brillantgrün, Chromazurol S, 1-Nitroso-2-naphthol und-Furildioxim. Durch die Analyse einer Cadmiumprobe mit dem Zusatz bekannter Mengen der zu bestimmenden Elemente wurden Genauigkeit und Präzision der vorgeschlagenen Methode erwiesen.     

Molecular and crystal structure of bis-quinolizidine immonium salts. IV. Δ1(6),11(16)-didehydro-sparteinium diperchlorate

^1(6),11(16)-Didehydrosparteinium diperchlorate,M _r =431.27, (C₁₅H₂₄N₂)²⁺ ·2C1O ₄ ^– , orthorhombic, C222₁,a=9.295(1),b=12.447(1),c=16.834(2) Å,V _c =1947.5(4) ų,Z=4,D _m =1.47 g cm^–3,D _c =1.47 g cm^–3,(CuK)=31.7 cm^–1. The finalR=0.052 for 733 counter reflections. The dication and the perchlorate anions lie on two-fold axes, and one perchlorate anion is disordered in two symmetrically equivalent positions. The two independent rings of the dication have conformations intermediate between half-chair and sofa, and the quinolizidine moiety (AB system) has a planar configuration.The title compound was obtained by mercuric acetate dehydrogenation of sparteine to ^5,11-didehydrosparteine and protonation of the latter in methanol with perchloric acid.¹³C-NMR spectra in DMSO-²H₆ and in²H₂O revealed the presence of the symmetrical diimmonium structure of the salt in solution.     

Enhancing performance of α-diiminonickel precatalyst for ethylene polymerization by substitution with the 2,4-bis(4,4'-dimethoxybenzhydryl)-6-methylphenyl group

High activities in ethylene polymerization predetermine α-diiminonickel precatalysts for potential industrial applications. In our study, we have synthesized and characterized a series of unsymmetrical 1-(2,4-bis(4,4′-dimethoxybenzhydryl)-6-MeC₆H₂N)-2-arylimino-acenaphthylene nickel(II) halides. The single-crystal X-ray diffraction study of representative compounds reveals distorted tetrahedral geometry. On activation with either Me₂AlCl or modified methylaluminoxane, these nickel complexes exhibit high activities of the order of 10⁶ g of PE (mol of Ni)⁻¹ h⁻¹ and produce polyethylene of generic application characterized by high molecular weight, narrow molecular weight distribution, and moderate degree of branching. The substituents at the ligands affect the catalytic performance of the nickel complexes and tune the microstructure of the resultant polyethylene.     

Application of HS-SPME with Poly(1-Vinyl-3-Hexylimidazolium Chloride) Polymeric Ionic Liquid Coating Using GC–MS to Determine Volatile Fatty Acids in Dairy Wastewater

Volatile fatty acids were determined in this study using headspace solid-phase microextraction (HS-SPME) with a poly(1-vinyl-3-hexylimidazolium chloride) polymeric ionic liquid coated fiber followed by gas chromatography–mass spectrometry. Experimental parameters such as extraction time and temperature, sample volume as well as desorption time and temperature were optimized. Detection limits of the method were in the range of 0.13–0.26 mg/L. The coefficient of variation ranged from 0.12 to 6.9 %. The method was applied to determine volatile fatty acids in dairy wastewater from different operations and in bulk wastewater.     

Synthesis and Antimicrobial Activities of New Polyhalogenated Benzimidazoles

A series of new polyhalogenated benzimidazoles has been synthesized and their antibacterial and antiprotozoal activity was evaluated. Several of new substituted halogenobenzimidazoles and their 2′‐deoxynucleosides showed noteworthy antiprotozoal toxicity particularly against Giardia lamblia. The most potent agents against bacteria and fungi were 4,5,6,7‐tetrachlorobenzimidazoles with polyfluoroalkyl chain at position 2 of the heterocyclus.     

Photophysical properties of a new DyLight 594 dye

We describe spectral properties of novel fluorescence probe DyLight? 594. Absorption and fluorescence spectra of this dye are in the region of Alexa 594 fluor spectra. The quantum yield of DyLight 594 in conjugated form to IgG is higher than corresponding quantum yield of Alexa 594 by about 50%. The new DyLight dye also shows slightly longer lifetime and photostability. These favorable properties and high anisotropy value, as well as a high cross-section for two-photon excitation, make this fluorophore attractive as a fluorescence probe in biochemical/biological studies involving fluorescence methods.     

Thermodynamics of titanium and vanadium reduction in non-aqueous environment calculated at various levels of theory

Reduction of titanium and vanadium compounds is a process accompanying the activation of coordinative olefin polymerization catalysts. Four density functional theory (DFT) functionals, coupled cluster with single, double, and perturbative triple excitations method CCSD(T) as well as complete active-space second-order perturbation theory method CASPT2 with a complete active-space self-consistent field CASSCF reference wave function were applied to investigate the thermodynamics of titanium and vanadium reduction. The performance of these theoretical methods was assessed and compared with experimental values. The calculations indicate that vanadium(IV) chloride is more easily reduced by trimethylaluminum than the corresponding titanium compound; the energies of reaction calculated at the CCSD(T) level are equal -57.21 and -33.10 kcal/mol, respectively. The calculations deal with the redox reactions of metal chlorides in the gas phase, rather than solvated ions in the aqueous solution. This approach may be more appropriate for olefin polymerization, usually carried out in nonpolar solvents.