Degradation of Phenolic Compounds in Aqueous Sucrose Solutions by Ozonation

The sugar industry is concerned with color formation due to the oxidation of phenolic compounds in the presence of carbohydrates. In this study, we investigated the ozonation of a mixture of five phenolic compounds in water and aqueous sucrose solution: p-coumaric (p-COU), caffeic (CAF), syringic (SYR), and chlorogenic (CHO) acids, as well as the flavonoid quercetin (QUE). The experiments were carried out in a 3-L glass reactor with magnetic stirring and a diffuser plate at the bottom to feed the ozone-oxygen gas mixture. Initial solution concentrations of 5 mg L?1 of each acid, 15 mg L?1 of quercetin, and 40 g L?1 of sucrose were used. The degradation of phenolic compounds followed apparent first-order kinetics, with rate constants and percent removals decreasing in the presence of sucrose. In water, average consumed ozone dosages of 10.4 and 18.7 mg L?1 were necessary for 50% and 90% removals, respectively, for CHO, CAF, and p-COU; for QUE they were slightly higher (13.9 and 20.5 mg L?1, respectively). At a consumed dosage of 20.8 mg O3 L?1, more than 99% removal was obtained for CHO, CAF, and p-COU, while 96.2% was achieved for SYR. In contrast, QUE revealed to be more recalcitrant during ozonation in the absence of sucrose, with only 70% removal at the highest consumed O3 dosage. The consumed ozone dosages for 50% and 90% removals were higher for CHO, CAF, and p-COU in aqueous sucrose solution, which may impact ozone consumption during real sugarcane juice treatment. Sucrose and t-butanol were the main influential parameters that significantly affected the total amount of phenolic compounds degraded.     

Thermogravimetry‐FTIR Analysis of Pyrolysis of Pyrolytic Lignin Extracted from Bio‐Oil

Pyrolytic lignin is attributed to the instability of bio‐oil but is a potential chemical material. To improve the stability and increase the economic viability of bio‐oil, high‐ and low‐molecular‐mass pyrolytic lignin (HMM and LMM) were obtained using solvent extraction. The microstructure of pyrolytic lignin was examined by Fourier transform infrared spectrometry (FTIR). The dissimilar absorption intensities indicated the different content of corresponding functional groups in HMM and LMM. The pyrolysis behavior of HMM and LMM was studied by thermogravimetry coupled with FTIR. Obviously pyrolytic lignin undergoes three weight loss stages.     

Ozonation of Some Aromatic Compounds in Aqueous Solution: Styrene,Benzaldehyde, Naphthalene,Diethylphthalate, Ethyl and Chloro Benzenes

This study presents the ozonation of some of the aromatic compounds frequently found in French surface waters and which have not been the object of fundamental studies in an aqueous medium. As far as the reactivity is concerned, we have determined the values of the ozone consumed per initial aromatic consumed (molar ratio, ozone demand), in a semi batch bubble column at slightly acidic pH. As for the ozonation products, the application of specific experimental procedures in high concentration aqueous solution after the use of derivatization reactions, allowed us to isolate (PLC, GC) and identify (GC/HS ; MS, NMR) some degradation products in the cases of benzaldehyde and naphthalene. The following of the development, in dilute aqueous solution of some ozonation products (HPLC, GC), is presented in the cases of styrene, benzaldehyde, naphthalene and diethylphthalate. On the basis of the results obtained, the mechanisms of initial steps of ozonation are examined in the case of styrene, of benzaldehyde and of naphthalene. Lastly, with regards to chlorobenzenes and ethylbenzenes, it was not possible to isolate the ozonation products The stripping by ozonated gas of theses compounds became more significant evenof overwhelmingly greatimportance. The results obtained are discussed at the light of the previous results with ozonation of polar aromatic compounds.     

双水相体系中成相及有机物分配机理的初步研究

双水相萃取技术应用广泛,但目前为止对其成相、萃取机理的研究尚不明朗。通过对丙酮、异丙醇、乙醇、甲醇和无机盐NaH2PO4、K2HPO4、(NH4)2SO4、NaCl、Na2CO3的双水相成相研究及对乙酸、苯酚和葡萄糖在乙醇/NaH2PO4体系内分布的研究,发现不同官能团对双水相成相及在双水相体系中物质分配的影响。其中,羟基表现为强亲水力,其它各基团表现为憎水力。这两种力的结果导致了有机溶剂与无机盐在水溶液中的分相行为,并决定了一种化合物在双水相体系中的分配。     

Ozonation of Sulfur-Containing Aliphatic Compounds in Aqueous Solution. I

In view of the possible reaction of ozone with sulfur containing natural and anthropogenic compounds, the oxidation products of sulfur-containing aliphatic model compounds in pure water in dependence on pH value were investigated.

In the first part, as a model compound for thioether, thiodiglycolic acid was investigated. The rate of elimination is independent of pH-value. At pH 3 as primary product thionyldiglycolic acid is formed, which undergoes further oxidation, but very slowly, to sulfonediacetic acid, which is very stable against ozone attack at pH 3. At pH 7 and higher, however, thionyldiglycolic acid is oxidized faster to sulfonediacetic acid, and this compound is oxidized to sulfoacetic acid, oxalic acid, glyoxylic acid, sulfateion, and CO₂ after longer reaction times. In all cases, sulfite as an inorganic intermediate product could not be identified. Also the intermediate products in pure solutions are ozonized. The mass balances show that 90 to 95% of the oxidation products could be identified. Based on these results, reaction schemes are discussed.     

Effects of Cultivars and Location on Quality, Phenolic Content and Antioxidant Activity of Extra-Virgin Olive Oils

Quality characteristics of extra-virgin olive oils depend on several factors. In order to study the effects of genotype and growing location on olive oil quality, olives from cv. Coratina, Nocellara, Ogliarola, and Peranzana, picked in four locations of the Apulia region (Italy), were crushed by a three-phase system to produce mono-cultivar extra virgin olive oils that were analyzed for acidity, peroxide value, spectrophotometric indices, total phenolic content, phenolic profile and antioxidant activity. The experimental data concerning peroxide value, spectrophotometric indices, phenolic content and profile and antioxidant activity showed great variability among the cultivars grown in the same location and also among the oils produced with olives of the same cultivar but grown in different locations. For each cultivar, no significant differences were found among locations in terms of acidity and ΔK whereas peroxide value, K₂₃₂, and K₂₇₀ differ significantly among locations for both Ogliarola and Peranzana cv. Concerning the phenolic content of Ogliarola cv., no differences were highlighted between the locations whereas the phenolic contents of Peranzana significantly changed as a function of the place of growing. On the basis of these results, the statistical multivariate analysis did not allow the classification into homogeneous groups neither of the oils belonging to the same cultivar nor of those obtained from olives picked in the same location.     

Ozonation of Anionic and Non-ionic Surfactants in Aqueous Solutions: Impact on Aquatic Toxicity

The objective of this study was to investigate the influence of ozonation of anionic and non-ionic surfactants on their aquatic toxicity. Toxicity values of various commercially important anionic and non-ionic surfactants have been determined using the luminescent bacterium Vibrio fischeri. Surface tension measurements were made to study the interfacial activity. The behavior depends on the chemical structure. Some intermediate ozonation products were found to be more toxic than the base surfactant and others were found to be less. Surfactants with aromatic rings such as linear alkyl benzene sulfonates, or surfactants with glycosidic groups such as alkylpolyglucosides, exhibit a lower toxicity after ozonation. On the other hand, ether groups present in the fatty-alcohol ethoxylates and ether carboxylic derivative surfactants, and carboxylic acid derivates present in the ether carboxylic derivative surfactants lead to increasing toxicity after ozonation. Surfactants with ether groups probably formed short-chain polyethoxylated compounds and carboxylic acids, which are possibly responsible for the surface-tension decrease that promotes the toxicity increase.     

Investigations on the Changes of Biological Degradability of Single Substances Induced by Ozonation

On the basis of our studies it can be demonstrated that toxic or difficultly degraded substances can be converted, by means of ozonolysis, to biologically active groups of substances. An excess of ozone of 3–6 g 0₃/g DOC is however necessary. Hater works generally employ doses of 1–2 g O3/ g DOC. This may be the reason for the observed destruction of biological activities in carbon filters since at low doses the dissolved substances may be only partially oxidised or poorly degradable intermediate products are formed. From this point of view the ozonolysis of some model compounds was performed. The reaction of aniline, bezene–sulfonicacid, 4–chloro–o–cresol , 2–nitro–p–cresol and humicacid with ozone show that after low ozone doses (1 g 03/g DOC) the products formed are not biodegradable as in the case of aniline (BOD5/COD=0,05) or that the intermediate products are hardly easier to degrade than the initial substances. B0D5/C0D values of 0,05 – 0,25 were found.The reactions of ozone with the model compounds and the properties of the oxidation products are described.     

Kinetic Regime Changes in the Ozonation of 1,3-Cyclohexanedione in Aqueous Solutions

The reaction between ozone and 1,3-cyclohexanedione in aqueous solutions at different pH was investigated from the point of view of the film theory. The rate of ozone absorption is accompanied by a second order irreversible reaction with 1,3-cyclohexanedione. The kinetic regime of absorption was found to change from fast (the reaction being of pseudo first order) to instantaneous, according to the ozone partial pressure applied. The former kinetic regime allows the determination of the reaction rate constant, while the latter leads to the volumetric mass transfer coefficient of the system.     

Influence of Water Deficit in Bioactive Compounds of Olive Paste and Oil Content

The main objective of this study was to evaluate the effect of different deficit irrigation treatments (control, regulated deficit irrigation [RDI]‐1, RDI‐2, and RDI‐3) on the phenolic profile of the olive paste and oil content. Irrigation treatments with more stress water led to a considerable increase in the phenolic compounds of olive paste, especially in oleuropein (60.24%), hydroxytyrosol (82%), tyrosol (195%), and verbascoside (223%) compared to control. A significant increase in the content of total flavonoids and phenolic acids was also observed for these samples. In virgin olive oils (VOO) elaborated from the most stressed olive trees (RDI‐2 and RDI‐3), a noticeable increase in phenolic substances with antioxidant properties (oleuropein, hydroxytyrosol, tyrosol, secoiridoid derivatives, and o‐vanillin) was observed. Consequently, water stress conditions improved antioxidant activity of VOO.     

The Effect of Germination on Phenolic Compounds and Antioxidant Activity of Pulses

In this study the changes of phenolic compounds and antioxidant activity of four different pulses namely white bean (Phaseolus vulgaris L), Common vetch (Vicia sativa), Lentil (Lens culinaris) and Chickpea (Cicer arietinum) seeds before and after germination were investigated. Seeds germinated in dark chambers maintained near 100 % relative humidity at 20 °C. Three different solvents namely acetone, hexane and methanol were employed to extract the phenolic compounds present in the seeds and sprouts. Total content of phenolic compounds was measured by the Folin–Ciocalteu method and antioxidant activity determined by the delay in fat oxidation. Different concentrations of extracts (0.02 and 0.1 % w/w) were added to tallow and the stabilities of the treatments were determined by the peroxide value and induction period measurements to evaluate the antioxidant activities. The results indicated that the increases in phenolic content from dormant seed to sprouted seed were significant (P ≤ 0.05) in all the samples. The significant differences between induction periods of tallow treated with sprouted seed extracts were observed (P < 0.05). The results indicated that the greatest increase in stability was obtained when tallow was treated with a 0.1 % concentration of acetone chickpea sprout extract. The pulses' sprout flour or extract might be recommended for use as a source of natural antioxidants in functional foods.     

类水滑石在有机液相氧化中的催化应用

综述了以类水滑石为催化剂的有机液相催化氧化的研究进展。分别介绍了利用类水滑石的碱性、阳离子可搭配性及阴离子可交换性的催化氧化体系，重点讨论了在精细合成中有广泛应用前景的绿色氧化方法，预测了类水滑石将在环境友好的有机氧化工业中起到越来越重要的作用。     

Tunable Aqueous Polymer Phase Impregnated Resins: A Combination of the Extractant Impregnated Resin Principle and Aqueous Two-Phase Systems

This scientific note introduces a concept supposed to enhance aqueous two-phase extraction by immobilizing one of the two phases of an aqueous two-phase system in porous particles. This approach, developed by the author, is based on solvent impregnated resins. The resulting so-called (tunable) aqueous polymer phase impregnated resins might avoid drawbacks of aqueous two-phase extraction, such as long phase separation times due to persistent emulsification. Due to the novelty of the idea and resulting current lack of fundamental studies, the idea is put up to discussion in order to initiate scientific exchange and hopefully widespread investigation of its true potential.     

Phenolic profiles of Turkish olives and olive oils

Phenolic compound distribution of Turkish olive cultivars and their matching olive oils together with the influence of growing region were investigated. One hundred and one samples of olives from 18 cultivars were collected during two crop years from west, south and south‐east regions of Turkey. The olives were processed to oils and both olive and olive oil samples were evaluated for their phenolic compound distribution. The results have shown that main phenolics of Turkish olives were tyrosol, oleuropein, p‐coumaric acid, verbascoside, luteolin 7‐O‐glucoside, rutin, trans cinnamic acid, luteolin, apigenin, cyanidin 3‐O‐glucoside and cyanidin 3‐O‐rutinoside. Oleuropein and trans cinnamic acid were present in higher amounts among all phenolics. Principal component analyses showed that the growing region did not have drastic effect on phenolic profile of olives. The major phenolic compounds of olive oils were tyrosol, syringic acid, p‐coumaric acid, luteolin‐7‐O‐glucoside, trans cinnamic acid, luteolin and apigenin. Luteolin is a predominant phenolic compound in almost all oil samples. Total phenol concentrations of Southeast Anatolian oils were found to be lower than those of the other regions.     

Phenolic compounds and some quality parameters of pumpkin seed oil

Pumpkin seed oil has become a recognized source of phenolic compounds. The main aim of this paper was to evaluate the concentration of phenolic compounds and their extraction from pumpkin seed oil. The total phenolics content (TPC) measured in the pumpkin seed oil samples ranged from 24.71 to 50.93 mg GAE/kg of oil. The individual phenolics were tyrosol, vanillic acid, vanillin, luteolin and sinapic acid. Hexane and acetone were the best solvents for the washing step, and methanol for the elution of the phenolics in the solid‐phase extraction (diol‐SPE), whereas bleaching caused a significant increase in the TPC obtained (24.5–30.7%). Additionally, some other oil characteristics were evaluated. The mean oxidative stability of the oils (OSI) was around 4 h, with 5.43 h for the most stable oil. The maximum antioxidant capacity measured by the reduction of the DPPH radical was 62%, which was comparable to 0.16 mM Trolox equivalent. The color of the oil was expressed by L*a*b* coefficients and its hue and saturation. Whereas all samples had similar lightness, their rates of green, red, yellow and blue color were different. Moreover, TPC correlated negatively with lightness, b* and saturation (–0.49, –0.48, and –0.43), and positively with a* and hue (0.58 and 0.52).     

Phenolic adhesives based on eucalyptus pyrolytic oil: Effect of urea addition on synthesis and properties

The present work aimed to evaluate the effect of urea addition on the synthesis parameters and properties of phenolic adhesives produced with oil from the pyrolysis of eucalyptus wood. The adhesive formulations were synthesized according to an entirely randomized design involving two formaldehyde/demethylated oil (F/DO) molar ratios (1.4 and 1.7), three NaOH/DO molar ratios (0.9, 1.0 and 1.1) and five levels of urea (0, 5, 10, 15 and 20%), totalizing 30 formulations. The following parameters and properties were obtained: reaction time (min) and temperature (°C); solids content (%), gel time (s), viscosity (cP) and pH. Regression analysis was performed and quadratic models were adjusted for reaction conditions (time and temperature) and some adhesive properties. Synthesis reactions were more controllable in terms of reaction time in the following conditions: urea addition in levels from 5 to 15% with F/DO molar ratio of 1.7 and NaOH/DO molar ratio of 1.0.     

The Ozonation of Glyoxylic Acid in Aqueous Solution: Chemical Products and Kinetics Evolution

The ozonation of glyoxylic acid in aqueous solution is investigated in semicontinuous and continuous reacting systems to follow the evolution of both chemical products and kinetics. Evidence is given of formation of small amounts of formic acid and -of the promoting effect of peroxidic intermediates upon oxalic acid ozonation. Kinetic results indicate that the ozonation process develops according to a radical chain mechanism initiated by ozone attack on glyoxylic acid.     

Phenolic Compounds and Antioxidant Capacity of Monovarietal Olive Oils Produced in Argentina

Virgin olive oil has high levels of phenolic compounds that are highly bioavailable; these compounds are receiving considerable attention for their antioxidant activity, closely related to the prevention of non‐communicable chronic diseases. The aim of this work was to characterize the phenolic profile and antioxidant capacity of monovarietal olive oils cvs. Arauco, Arbequina, Farga and Empeltre produced in Argentina. This study focused on the relationship between the single molecules or classes of molecules quantified by SPE‐CZE, the corresponding Folin‐Ciocalteu results, and antioxidant capacity using three different tests. Fifteen compounds were simultaneously determined: tyrosol, vinylphenol, oleuropein, hydroxytyrosol, rutin, catechin, naringenin, cinnamic acid, chlorogenic acid, syringic acid, luteolin, apigenin, vanillin acid, quercetin, and caffeic acid. The phenolic contents of the monovarietal olive oils show significant differences between different varieties (p < 0.05), with positive and significant Pearson's correlation found between Folin–Ciocalteu and CZE. Besides, the correlation between the content of total polyphenols and antioxidant capacity was high for all the antioxidant assays performed. When analyzing the correlation coefficients of the different families of phenolic compounds studied, simple phenols and cinnamic acid derivatives show a higher correlation with antioxidant capacity. Thus, findings obtained in this study demonstrated that Arauco olive oil, autochthonous for Argentina, possesses the highest antioxidant/free‐radical scavenging properties, which are very likely due to the presence of high contents of phenolic compounds.     

Predicting Partitioning in Aqueous Two-Phase Systems and the Effects of Temperature Changes

Abstract

The use of aqueous two-phase extraction can be attractive for some separations, but the choice of such systems is frequently done in an empirical manner. Predictive models are needed for optimal design, but previous ones appear to have limitations. In addition, these systems have usually been used previously at temperatures around 25°C; however, it is possible that better separations may be achieved at other temperatures. An equation is developed here which can predict partitioning for a wide range of solutes. The effect of temperature on partitioning has been determined, and this can also be predicted by using the equation. Thus, this model may prove quite useful in designing and optimizing extractive separations.