Search Results
Introduction Phenol is an organic compound of an anthropogenic origin, which is widely used in phenolic resins and plywood adhesives among others, and is also found in petroleum products, such as coal tar and creosote [ 1
use of natural resources and energy ( Yüzbaşıoğlu, 2018 ). Phenolic compounds are secondary metabolites produced by plants during growth and reproduction, as well as in response to a number of biotic and abiotic stresses. Phenols having antioxidant
. P andino , G. , L ombardo , S. , M auromicale , G. & W illiamson , G. ( 2011 ): Profile of polyphenols and phenolic acids in bracts and receptacles of globe artichoke ( Cynara cardunculus var. scolymus ) germplasm . J. Food Compos. Anal
Introduction: In patients with chronic kidney disease (CKD), uremic toxins accumulate in blood and cannot be excreted with urine. Accumulation of these toxins has negative effects on many body functions. Because of the importance of these toxins, we developed and validated a simple, sensitive, accurate, and precise method for the determination of two main uremic toxins: phenol and p-cresol in human urine. Materials and methods: Separation of these analytes in urine samples was achieved by reverse-phase high-performance liquid chromatography (RP-HPLC) with a C18 column at 35 °C using the mobile phase of methanol–water (65:35) at a flow rate of 1.4 mL min−1. Fluorimetric detection was used at 284 nm for excitation and 310 nm for emission. Results: The method is linear over the range of 1.5–35 ng mL−1 and 1–45 ng mL−1 for phenol and p-cresol, respectively. The method was applied to urine samples from 10 healthy subjects and 10 chronic kidney disease patients. Conclusions: This assay appears to be useful in routine analysis of clinical samples for simultaneous determination of phenol and p-cresol levels in urine.
Abstract
O-Alkylation of phenol compounds was performed in a continuous flow apparatus under biphasic liquid/liquid conditions and promoted by tetrabutylammonium bromide (TBAB) as a phase-transfer catalyst. The segmented flow that is generated within the flow system is able to afford the desired ethers in high yield and in very short times.
Thermal analysis of aqueous micellar solutions
Study of some structural transitions and of solute-surfactant complexes
Abstract
A micro differential temperature scanning calorimeter was used to characterize the structural changes between different types of micelles in aqueous solutions of ionic surfactants: anionic — sodium dodecylsulfate (SDS) — and cationic — hexadecyltrimethyl ammonium bromide (CTAB). Moreover, this technique allowed to confirm the existence of peculiar types of complexes between surfactants and selected solutes. In SDS solutions containing polyethylene glycols (PEG), the presence of complexes formed by small micelles adsorbed along the chains of the polymers was evidenced in the case of long enough polymer chains. In CTAB-phenol solutions, due to strong interactions between the polar heads of surfactant and phenol, molecular complexes of a composition of 1:1 molar ratio have been characterized. Depending on the ratio [phenol]/[CTAB], the rheological behaviour was found to change from fluid to viscoelastic and gel-like solutions, owing to the growth of elongated rod-like micelles. With entangled worm-like micelles, the important role of kinetics to reach the thermodynamic equilibria was shown.
49 5679 5684 Asami, D.K, Hong, Y.-J., Barret, D.M., Mitchell, A.E. 2003. Comparison of the total phenolic and ascorbic acid content of freeze
CeO2-catalyzed ozonation of phenol
The role of cerium citrate as precursor of CeO2
mineralization rates of organic pollutants [ 22 , 23 ]. In this study, CeO 2 , in three morphological forms, was used for catalytic ozonation of phenol. The correlation between properties of citrate-based precursors of oxides, oxide morphologies, and
Thermal degradation of lignin–phenol–formaldehyde and phenol–formaldehyde resol resins
Structural changes, thermal stability, and kinetics
Introduction The manufacturing process of phenol–formaldehyde (PF) resins has remained unchanged for several decades. However, numerous efforts have been carried out to reduce the dependence of this industry on phenol, the cost
Amarowich, R., Weidner, S. (2009) Biological activity of grapevine phenolic compounds. In: Roubelakis-Angelakis, K. A. (ed.) Grapevine Molecular Physiology and Biotechnology . Springer Science+Business Media B
