Abstract
The self-condensation reactions of 2- and 4-mono-methylol phenols (2-MMP and 4-MMP), in the presence of varying concentrations of NaOH, have been studied by differential scanning calorimetry (DSC). The reaction exotherms were analysed to derive the activation energy, Ea, and the heat of reaction, HT, for the condensation reactions. In the case of 2-MMP an increase in NaOH:2-MMP molar ratio caused an increased in Ea and a decrease in HT up to a molar ratio of 0.6:1. However, for 4-MMP, an increase in NaOH concentration caused an increase in Ea up to a molar ratio of 0.3:1 beyond which there appeared to be no further effect. The presence of NaOH had no effect on HT for this compound. The results suggest that in the range of NaOH concentration used the effect of NaOH was substantially greater on 2-MMP compared to 4-MMP.
Abstract
Some systems of extraction of phenols from aqueous solutions (R=97–99%) are recommended. Methods of separate extraction-potentiometric determination of phenol and alkylphenols in nonaqueous extracts are developed.
fruit juices [ 8 , 10 ]. Due to reported anticarcinogenic properties of some flavonoids, demand for fruits with anthocyanidin and anthocyanin content has been increasing [ 11 ]. Despite their low content in fruits and vegetables, phenolic
insecticide and phenolic elicitor treatment . Biores. Technol. 98 : 623 – 632 . Iyengar , E.R.R. , Reddy , M.P. 1996 . Photosynthesis in highly salt tolerant plants . In
. 2009 : Phenolic compounds and temporal perception of bitterness and pungency in extra-virgin olive oils: Changes occurring throughout storage . Food Chem. , 113 , 1095 – 1100
References Ainsworth , E.A. , Gillespie , K.M. 2007 . Estimation of total phenolic content and other oxidation substrates in plant tissues using Folin
Phenolic acids in the leaves, roots, and fruits of Peucedanum verticillare L. Koch ex Dc have been qualitatively determined for the first time by the method of one- and two-dimensional TLC on cellulose layers. Phenolic acids in P. verticillare have not previously been studied.
. Iconomou , D. , Arapoglou , D. & Israilides , C. ( 2010 ): Improvement of phenolic antioxidants and quality characteristics of virgin olive oil with the addition of enzymes and nitrogen during olive paste processing . Grasas Aceites
): Antioxidant capacity and total phenolic content of Malaysian underutilized fruits. J. Fd Compos. Anal. , 22 , 388–393. Mokhtar R.A.M. Antioxidant capacity and total phenolic content of
The possibility of using aminopropylsilica TLC plates for determination of phenolic acids has been investigated. Eighteen phenolic acids were chromatographed on aminopropyl-bonded silica with mobile phases comprising mixtures of diisopropyl ether and acetic acid with toluene, petroleum ether, or heptane. The selectivity of the proposed chromatographic systems was satisfactory. The best separations were obtained with heptane-diisopropyl ether-acetic acid, 4 + 5 + 1 ( v / v ) or petroleum ether-diisopropyl ether-acetic acid, 6 + 3 + 1 ( v / v ) as mobile phase.
