Feasibility study for the use of near infrared spectroscopy in the qualitative and quantitative analysis of green tea, Camellia sinensis (L.)

This paper indicates the possibility to use near infrared spectroscopy (NIR) combined with PLS as a rapid method to estimate the quality of green tea. NIR is used to build calibration models to predict the content of caffeine, epigallocatechin gallate (EGCG) and epicatechin (EC) and for the prediction of the total antioxidant capacity of green tea. For the determination of the total antioxidant capacity, the trolox equivalent antioxidant capacity (TEAC) method is used. Until now, the prediction of the antioxidant capacity as such by use of NIR has not been reported. For caffeine and TEAC, models are build for the whole green tea leaves and also for the ground leaves. For the polyphenols (EGCG and EC), only models for the whole leaves are investigated. A partial least squares (PLS) algorithm is used to perform the calibration. To decide upon the number of PLS factors included in the PLS model, the model with the lowest root mean square error of cross-validation (RMSECV) for the training set is chosen. The correlation coefficient (r) between the predicted and the reference results for the test set is used as an evaluation parameter for the models: for the TEAC results r=0.90 for the model with the whole leaves, r=0.86 for the model with the powdered leaves are obtained. The caffeine prediction model has a correlation coefficient r=0.96 for the whole leaves and r=0.93 for the ground leaves. The correlation coefficient for the EGCG and the EC content models are, respectively 0.83 and 0.44.     

SnCl2-mediated carbonyl allylation in fully aqueous media

Systematic studies were performed on SnCl₂-mediated carbonyl allylation reaction between aldehydes and allyl halides in fully aqueous media. Totally three valuable reaction systems were discovered, which were SnCl₂/CuCl₂, SnCl₂/TiCl₃, and SnCl₂/PdCl₂. They all provided good to excellent yields in the allylation of aliphatic and aromatic aldehydes under very mild and convenient conditions. SnCl₂, by itself, was also found to be effective for the allylation reaction when allyl bromide was employed. However, the SnCl₂-only reaction could only tolerate very small amount of water as the solvent. The SnCl₂/CuCl₂, SnCl₂/TiCl₃, and SnCl₂/PdCl₂-mediated reactions exhibited good regioselectivity favoring the γ-adduct when cinnamyl halides were employed as the allylation reagent. The same reactions with cinnamyl halides also showed good diastereoselectivity favoring the anti-product. Mechanistic studies using proton NMR techniques suggested that the additive (i.e., CuCl₂, TiCl₃, PdCl₂) could accelerate the formation of allyltin intermediate, but this step was shown not to be the most important for the allylation. Thus we proposed that the Lewis acid catalysis effect exerted by the additive was the main reason for the observed reactivity enhancement.     

Eco-dyeing and functional finishing of wool fabric based on Portulaca oleracea L. as colorant and Musa basjoo as natural mordant

Biomass energy is the most acknowledged renewable resource due to its universality, richness, and renewability. This study utilized a Portulaca oleracea L. plant as a natural colorant for wool fabric dyeing with a high color yield at optimum extraction and dyeing conditions. To evaluate the dyeing mechanism and feasibility of the extracted dyes, we analyzed and characterized the molecular structure and nano-level particle size. The dyeing kinetics and the morphology of dyed fabrics were integratedly explored; the adsorption process of wool fabric on natural colorant molecules was increasingly in line with the pseudo-second-order kinetic adsorption model. Further, the dyeing effects of wool fabrics were compared to that of Musa basjoo mordant and synthetic dyes to confirm the superior color depth (K/S value 23.53), biological function as anti-ultraviolet (UPF value 253.47), and anti-bacterial activity (antibacterial rate of Staphylococcus aureus/Escherichia coli was 71.3%/37%). Our findings provide a feasible scheme for providing deep color and biological activity to wool fabrics. This has broad application prospects in the field of eco-friendly textile materials.     

Catalytic Method for Synthesis of Aspirin by a Green,Efficient and Recyclable Solid Acid Catalyst (Preyssler's Anion) at Room Temperature

Synthesis of aspirin at room temperature via O‐acetylation of salicylic acid in the presence of Preyssler type heteropolyacids has been investigated in order to contribute toward clean technology, which is the most important need of the society. All of the catalysts are recyclable and reusable.     

Role of resonances in building cross sections: Comparison between the Mittag–Leffler and the T‐matrix Green function expansion approaches

Peaks in collision cross sections are often interpreted as resonances. The complex dilation method, as well as other methods relying on analytic continuation of the scattering formalism, can be used to clarify whether these structures are true resonances in the sense that they are poles of the S‐matrix and the associated Green function. The performance of the Mittag–Leffler expansion and T‐matrix Green function expansion methods are formally and computationally compared. The two methods are applied to two model potentials. Eigenenergies, s‐wave residues, and cross sections are computed with both methods. The resonance contributions to the cross sections are further analyzed by removing the residue contributions from the Mittag–Leffler and Green function expansion sums, respectively. It is suggested that the contribution of a resonance to a cross section should be defined through its S‐matrix residue. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007     

Nitroarene catalyzed oxidation with sodium percarbonate or sodium perborate as the terminal oxidant

A new catalytic oxidation method for the preparation of aromatic carboxylic acids from methyl aryl ketones is reported. The method is an alternative to the haloform reaction; it is benign and affords the desired product without production of any harmful side products. The catalytic cycle is based on the use of an electron-deficient nitroarene as catalyst with either of the two cheap and green oxidants sodium percarbonate or sodium perborate. The method gives a good yield (87%) and shows excellent selectivity when the model substrate (acetophenone) is oxidized. A series of benzoic acids of industrial interest were prepared by means of this method.     

Green chemistry and sustainability metrics in the pharmaceutical manufacturing sector

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Wiener distributions and white noise analysis

The paper describes the structure of a new space of generalized Wiener functionals, , called the Wiener algebra, or space of Wiener distributions, and demonstrates its use in the white noise analysis. The concepts of derivatives and integrals for multi-time parameter generalized stochastic process:^N are introduced, and a derivative version of Itô's lemma is proved. The algebraic structure of and its lattice of subspaces is elaborated, and within this framework a generalized version of the Malliavin calculus is presented.     

Solvent-free microwave extraction of essential oil from aromatic herbs: comparison with conventional hydro-distillation

Solvent-free microwave extraction (SFME) is a combination of microwave heating and dry distillation, performed at atmospheric pressure without added any solvent or water. Isolation and concentration of volatile compounds are performed by a single stage. SFME has been compared with a conventional technique, hydro-distillation (HD), for the extraction of essential oil from three aromatic herbs: basil (Ocimum basilicum L.), garden mint (Mentha crispa L.), and thyme (Thymus vulgaris L.). The essential oils extracted by SFME for 30min were quantitatively (yield) and qualitatively (aromatic profile) similar to those obtained by conventional hydro-distillation for 4.5 h. The SFME method yields an essential oil with higher amounts of more valuable oxygenated compounds, and allows substantial savings of costs, in terms of time, energy and plant material. SFME is a green technology and appears as a good alternative for the extraction of essential oils from aromatic plants.     

Eco-friendly synthesis of high silica zeolite Y with choline as green and innocent structure-directing agent

Zeolite synthesis in contemporary chemical industries is predominantly conducted using organic structure-directing agents (OSDAs), which are chronically hazardous to humans and the environment. It is a growing trend to develop an eco-friendly and nuisanceless OSDA for zeolite synthesis. Herein, choline is employed as a non-toxic and green OSDA to synthesize high silica Y zeolite with SiO₂/Al₂O₃ ratios of 6.5–6.8. The prepared Y zeolite samples exhibited outstanding (hydro)thermal stability at ultrahigh temperature owing to the higher SiO₂/Al₂O₃ ratio. The XRF, SEM, ²⁹Si-NMR and ¹³Na+ results suggested that choline plays a structure-directing role in the synthesis of Y zeolite, while the feed molar fraction of Na⁺ is a crucial determinant for the framework SiO₂/Al₂O₃ ratio and the crystal morphology.