Reaction Of Phloroglucinol Research Articles

Дифференциация плюсовых деревьев сосны обыкновенной по состоянию ксилемы

An essential stage in the establishment of seed orchards is the formation of an optimal composition, avoiding inbreeding depression in the produced seed material, which develops as a result of crossbreeding between closely related plus trees. The negative effect can be reduced by ensuring the genetic heterogeneity of the seeds. The purpose of this study is to give a relative evaluation of the plus trees of Scots pine (Pinus sylvestris L.) as one of the most economically significant tree species on the European continent according to their physiological conditions. The formation and lignification of the xylem of the plus trees were investigated in the Nizhny Novgorod region of Russia. A histochemical examination was performed using the reaction of phloroglucinol to lignin. Phenotypic differences in the physiological conditions of plus trees appeared on a uniform ecological background that indicates their genotypic determinism. This fact was confirmed by ANOVA. The share of the influence of differences between the proper plus trees was between 25.16±8.91 % and 53.98±5.48 %. According to the results of the factor and cluster analysis, the association of plus trees was generated by the similarity of the multidimensional estimates of the xylem conditions. The objects that were statistically most distant from the others were determined. The hereditary conditionality of the identified differences among plus trees allows us to consider their grouping into clusters as genotypically determined. This information provides a reasonable approach to the formation of an assortment of Scots pine clonal seed orchards. For citation: Besschetnova N.N., Besschetnov V.P., Babich N.A., Bryntsev V.A. Differentiation of Plus Trees of Scots Pine by Xylem Conditions. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 4, pp. 9–25. (In Russ.). https://doi.org/10.37482/0536-1036-2023-4-9-25

High fixed carbon and low ash hydrochar production from sewage sludge with addition of phloroglucinol: Theoretical modeling of reaction mechanism using density functional theory

The addition of phloroglucinol in hydrothermal carbonization of sewage sludge resulted in production of advanced sludge hydrochar with improved chemical structure and composition, which create conditions for its higher-value applications. Experimental results showed that the formation of some nanoparticle clusters rather than sheet sedimentary was observed due to enhancement of aromatic structures. Carbon content of hydrochar was increased by 15.42% and ash content was reduced by 25.68% when compared to single hydrothermal carbonization of sewage sludge. Moreover, reaction mechanism of phloroglucinol was investigated using density functional theory based on consideration of 5-hydroxymethylfurfural (5-HMF) and its hydration product levulinic acid as key active intermediates from degradation of saccharides that are one of the primary components of sewage sludge. Electrophilic substitution between phloroglucinol and 5-HMF is much easier than intermolecular dehydration due to the lower energy barrier and higher reaction rate constant. The precursors from electrophilic substitution preferentially occupied the core of hydrochar whereas that from intermolecular dehydration narrowly existed at outer surface. Reaction of phloroglucinol with levulinic acid also occurred easily by the electrophilic substitution, but which was limited by hydration of 5-HMF to form levulinic acid. Reaction pathway of phloroglucinol was mainly controlled by kinetics rather than thermodynamics.

Carbon Aerogels With Kaolin Addition For Supercapacitors Application

Carbon aerogels with excellent electrochemical properties and 3D porous structure are prepared from the reaction of phloroglucinol (P), resorcinol (R) and formaldehyde (F) under ascorbic acid (VC) catalyzing with kaolin (KL) addition. Because of the double-layer capacitance behavior, CAs have been used as supercapacitors for energy storage. The reaction mechanism of the wet aerogels formation is analyzed. Meanwhile, the chemical environments of CAs surface is systematically investigated using X-ray photoelectron spectroscopy (XPS). The cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) measurements and electrochemical impedance spectroscopy (EIS) are adopted to studied the excellent electrochemical properties of different samples. The specific capacitance (SC) is up to 162 F g−1, and 97% of initial capacitance is retained over 1000 cycles at a current density of 1.0 A g−1.

Highly efficient and green synthesis of diacylphloroglucinol over treated natural zeolite mordenite and the optimization using response surface method (RSM)

Herein, we report a greener and highly efficient route for the Friedel-Craft acylation of phloroglucinol over Indonesian treated natural zeolite mordenite (nHZMOR) catalyst to provide value-added diacylphloroglucinol derivatives under solvent-free conditions. The nHZMOR showed a high catalytic performance in Friedel-Craft acylation of a phloroglucinol reaction, and diacylphloroglucinol derivatives were obtained in excellent yields. The advantages of the use of this catalyst are solvent-free, shorter reaction time, high yields, and its recyclable ability. Easy catalyst separation was demonstrated through filtration and reused several times without noticeably decreasing its catalytic activity; however, with regeneration treatment, its catalytic performance can be improved. The effect of catalyst loading, reaction temperature, solvent effect and reaction time has been extensively studied. In addition, the chemical process was enhanced by the use of coupling automated synthesis equipment with the Response Surface Method (RSM) to optimize the Friedel-Craft acylation reaction. Also, a reasonable reaction mechanism had presented.

A DFT mechanistic and kinetic study on the reaction of phloroglucinol with •OH in different media: Hydrogen atom transfer versus oxidation

A theoretical study on the reaction of phloroglucinol with •OH has been performed with the aim of elucidating the geometric, energetic and kinetic properties of the reaction as well as identifying the preferred reaction pathway. Three reaction mechanisms have been considered, namely, direct hydrogen atom abstraction, addition–elimination mechanism in the absence and in the presence of a base catalyst and oxidation mechanism in the absence and in the presence of O2. The study has been performed using the DFT/M06[Formula: see text]2X, DFT/BHHLYP and DFT/MPW1K methods in conjunction with either the 6-31++G(d,p) or the 6-311++G(3df,2p) basis set. The energetic parameters are influenced by the type of function utilized and the media in which the calculation is done. The direct hydrogen abstraction mechanism provides the smallest branching ratio with respect to the •OH addition mechanisms. The PG + •OH reaction under atmospheric conditions saturated with O2 would predominantly form tetrahydroxybenzene; the predominant product within the biological system would largely depend on physiological conditions; under pH [Formula: see text] 7 and with oxygen dissolved within the biological system, the preferred product would be tetrahydroxybenzene; however, if the reaction takes place in some part of the biological system where the pH [Formula: see text] 7, the preferred product would be the phenoxyl radical.

Optimisation of headspace solid phase microextraction for the analysis of polychlorinated biphenyls and organochlorine pesticides in human milk samples

Adsorption capacity is the major sensitivity-limited factor in solid-phase microextraction. Due to its light-weight properties, large specific surface area and high porosity, especially tunable pore structures, the utilization of porous organic polymers as solid-phase microextraction adsorbents has attracting researchers' attentions. However, these works mostly concentrated on the utilization of specific porous organic polymers for preparing high-performance solid-phase microextraction coatings. The relationship between pore structures and adsorption performance of the porous organic polymers still remain unclear. Herein, three porous organic polymers with similar properties but different pore distributions were prepared by condensation polymerization reaction of phloroglucinol and terephthalaldehyde, which were fabricated as solid-phase microextraction coatings subsequently. The adsorption capacity of the porous organic polymers-coated fibers were evaluated by using benzene and its derivatives (i.e.,benzene, toluene, ethylbenzene and m-xylene) and polycyclic aromatic hydrocarbons as the target analytes. The results showed that the different adsorption performance of these porous organic polymers was mainly caused by their different pore volumes instead of their surface areas or pore sizes. Finally, the proposed method by using the mesoporous organic polymer coating was successfully applied to the determination of benzene and its derivatives in environmental water samples. As for analytical performance, high pre-concentration factors (74–2984), satisfactory relative recoveries (94.5 ± 18.5–116.9 ± 12.5%), intraday precision (2.44–5.34%), inter-day precision (4.62–7.02%), low limit of detections (LODs, 0.10–0.29 ng L−1) and limit of quantifications (LOQs, 0.33–0.96 ng L−1) were achieved under the optimal conditions. This study provides an important idea in the rational design of porous organic polymers for solid-phase microextraction or other adsorption applications.

Porous organic polymers with different pore structures for sensitive solid-phase microextraction of environmental organic pollutants

Adsorption capacity is the major sensitivity-limited factor in solid-phase microextraction. Due to its light-weight properties, large specific surface area and high porosity, especially tunable pore structures, the utilization of porous organic polymers as solid-phase microextraction adsorbents has attracting researchers' attentions. However, these works mostly concentrated on the utilization of specific porous organic polymers for preparing high-performance solid-phase microextraction coatings. The relationship between pore structures and adsorption performance of the porous organic polymers still remain unclear. Herein, three porous organic polymers with similar properties but different pore distributions were prepared by condensation polymerization reaction of phloroglucinol and terephthalaldehyde, which were fabricated as solid-phase microextraction coatings subsequently. The adsorption capacity of the porous organic polymers-coated fibers were evaluated by using benzene and its derivatives (i.e.,benzene, toluene, ethylbenzene and m-xylene) and polycyclic aromatic hydrocarbons as the target analytes. The results showed that the different adsorption performance of these porous organic polymers was mainly caused by their different pore volumes instead of their surface areas or pore sizes. Finally, the proposed method by using the mesoporous organic polymer coating was successfully applied to the determination of benzene and its derivatives in environmental water samples. As for analytical performance, high pre-concentration factors (74–2984), satisfactory relative recoveries (94.5 ± 18.5–116.9 ± 12.5%), intraday precision (2.44–5.34%), inter-day precision (4.62–7.02%), low limit of detections (LODs, 0.10–0.29 ng L−1) and limit of quantifications (LOQs, 0.33–0.96 ng L−1) were achieved under the optimal conditions. This study provides an important idea in the rational design of porous organic polymers for solid-phase microextraction or other adsorption applications.

Design of carbon materials with ultramicro-, supermicro- and mesopores using solvent- and self-template strategy for supercapacitors

We design a novel solvent- and self-template strategy to fabricate carbon materials with ultramicro-, supermicro- and mesopores through a simple solvothermal reaction of phloroglucinol and terephthaldehyde in dioxane using acetic acid as the catalyst, followed by carbonization. Dioxane serves simultaneously as a solvent in the reaction system and a template to generate mesopores (3.6 nm). Meanwhile, phloroglucinol/terephthaldehyde polymeric organic frameworks act as a self-template to produce regular and well-developed ultramicropores (0.54 nm) and some supermicropores (0.86 and 1.3 nm) during carbonization. High specific surface area (1003 m2 g−1) coupled with hierarchical porous structure endow the resultant carbon electrode excellent electrochemical properties including a satisfactory specific capacitance (214 F g−1 at 1.0 A g−1), excellent rate capability (154 F g−1 at a very high current density of 50 A g−1) as well as superb long-term cycling stability (95.5% retention of initial capacitance after 10000 cycles) in alkaline electrolyte. Compared with traditional synthetic strategy for porous carbons, the present approach can be easily carried out, avoiding tedious procedure, customized hard/soft template or extra activation step, and thus highlights new opportunities towards the simple and highly efficient synthesis of well-designed porous carbons for supercapacitor applications.

Efficient and Rapid Photocatalytic Reduction of Hexavalent Chromium Achieved by a Phloroglucinol-Derived Microporous Polymeric Organic Framework Solid

A microporous polymeric organic framework (POF) based on phloroglucinol (phlo-POF) was for the first time evaluated on photoreduction and removal processes of hexavalent chromium (Cr6+) from aqueous solutions. The phlo-POF synthesis was based on reaction of phloroglucinol and terephthalaldehyde under hydrothermal conditions. Structural and chemical characterization was performed using UV–vis–NIR diffuse reflectance spectroscopy (DRS), FT-infrared spectroscopy, and thermogravimetric methods, while surface area analysis was employed to determine other physical and surface properties. Batch experiments were conducted on contaminated water to determine the rate and extent of Cr6+ removal and its immobilization by the phlo-POF material. The kinetic studies showed a rapid removal of Cr6+ ions from the water in the presence of the phlo-POF, best described by the zero-order kinetic model. The efficiency of the material with UV–C irradiation on Cr6+ reduction was compared with a well-studied material, the Degussa ...

Analytical Validation of a New Enzymatic and Automatable Method for d-Xylose Measurement in Human Urine Samples.

Hypolactasia, or intestinal lactase deficiency, affects more than half of the world population. Currently, xylose quantification in urine after gaxilose oral administration for the noninvasive diagnosis of hypolactasia is performed with the hand-operated nonautomatable phloroglucinol reaction. This work demonstrates that a new enzymatic xylose quantification method, based on the activity of xylose dehydrogenase from Caulobacter crescentus, represents an excellent alternative to the manual phloroglucinol reaction. The new method is automatable and facilitates the use of the gaxilose test for hypolactasia diagnosis in the clinical practice. The analytical validation of the new technique was performed in three different autoanalyzers, using buffer or urine samples spiked with different xylose concentrations. For the comparison between the phloroglucinol and the enzymatic assays, 224 urine samples of patients to whom the gaxilose test had been prescribed were assayed by both methods. A mean bias of −16.08 mg of xylose was observed when comparing the results obtained by both techniques. After adjusting the cut-off of the enzymatic method to 19.18 mg of xylose, the Kappa coefficient was found to be 0.9531, indicating an excellent level of agreement between both analytical procedures. This new assay represents the first automatable enzymatic technique validated for xylose quantification in urine.

The Bis(triethylammonium) Salt of 3,5,12- Trinitrotricyclo[5.3.1.12,6]dodecan-8,10,11-trione-3,8-(NO2,O)-dianion

Reaction of phloroglucinol with s-trinitrobenzene and triethylamine results in formation of the deep red bis-triethylammonium salt of 3,5,12-trinitrotricyclo[5.3.1.12,6]dodecan-8,10,11-trione-3,8-(NO2,O) dianion, [(C6H15NH)+]2 (C12H7N9)2−. Crystals are monoclinic, and at 150(2) K a = 6.8612(7), b = 35.284(3), c = 11.0118(15) A, β = 94.601(10)°, and V = 2657.3(5) A3 with Z = 4. Both enolate and nitropropenenitronate groups are delocalized with lengthened C–O and N–O distances and shortened intervening C–C distances. The neutral nitro group at C12 has been determined to be endo to the nitroproprene nitronate. Triethylammonium ions form N+–H··O Hydrogen-bonds with the enolate oxygens and weaker methylene C–H··O contacts with the nitronates. Phloroglucinol, s-trinitrobenzene and trimethylamine react to form a tricyclic dodecane dianion, which has been isolated as its bis(triethylammonium) salt.

Ethyl-2-(3,5-Dihidroxyfenol): Phloroglucinol derivatives as potential anticancer material

Ethyl-2-(3,5-dihidroxyfenol) based phloroglucinol compounds have been synthesized. Ethyl-2-(3,5-dihidroksifenol) were synthesized by reacting phloroglucinol with ethyl 2-chloro acetate in excess. Phloroglucinol reaction using 2-chloro ethyl acetate was carried out under reflux for 24 hours at a temperature of 56 oC. The reaction products were identified by a thin layer chromatography and were characterized by melting point test. Analysis of the structure of the products was obtained by FTIR spectrophotometer, H-NMR, and 13C-NMR. The result of the reaction between phloroglucinol and 2-chloro ethyl acetate was brownish black solid, and has a melting point of 191 oC. Based on the structural analysis by FTIR, 1H-NMR and 13C-NMR, the reaction product was a mixture of compounds which is ethyl 2- (3,5-dihidroksifenol) acetate, ethyl-2-(2,4,6-trioxocyclohexyl) acetate, and the rest of phloroglucinol which can not react.

ChemInform Abstract: Cerium(III)‐Catalyzed Regioselective Coupling of 2‐Hydroxychalcones and Polyphenols: An Efficient Domino Approach Towards Synthesis of Novel Dibenzo‐2,8‐dioxabicyclo[3.3.1]nonanes.

AbstractThe reaction proceeds through regioselective Michael addition‐bicyclization cascade.

Aqueous-phase hydrodeoxygenation of highly oxygenated aromatics on platinum

Utilization of renewable sugars from biomass by a hybrid chemical process produces highly oxygenated aromatic compounds, such as phloroglucinol, which require catalytic reduction for desirable aromatic products. Aqueous phase hydrodeoxygenation of phloroglucinol on carbon-supported platinum produces resorcinol, phenol, cyclohexanol, cyclohexanone, and 1,3-cyclohexanediol by combinations of carbon–oxygen bond cleavage and carbon–carbon double bond hydrogenation. Carbon–carbon σ-bond cleavage was not observed. Hydrodeoxygenation was the primary reaction of phloroglucinol, leading to the production of resorcinol in the overall rate-limiting reaction, with an activation energy barrier of Ea = 117 kJ mol−1. Subsequent reactions of resorcinol produced 1,3-cyclohexanediol and phenol with similar energy barriers, Ea = 46 and Ea = 54 kJ mol−1, respectively. Further hydrogenation of phenol (Ea = 42 kJ mol−1) occurs through the intermediate, cyclohexanone, which is further reduced (Ea = 14 kJ mol−1) to the dominant product, cyclohexanol.

Coordination Polymers of Silver(I) with the Flexible Tritopic Ligand 1,3,5-Tri(4-cyanophenoxy)benzene: Guest Inclusion and Luminescent Properties

A new flexible tritopic ligand, 1,3,5-tri(4-cyanophenoxy)benzene (1), was synthesised by the reaction of phloroglucinol and para-fluorobenzonitrile. Compound 1 crystallises in the non-centrosymmetric space group Pna21. The reaction of ligand 1 with AgBF4 in the presence of different aromatic guest molecules was found to result in coordination polymers, namely, {[Ag3(1)2(BF4)3(H2O)2]·2C7H8·2CH2Cl2}n (2), {[Ag3(1)2(BF4)3(H2O)2]·2C6H6·2CH2Cl2}n (3). The crystal structures of 2 and 3 reveal that ligand 1 is linked by AgI ions into three-dimensional networks containing channels that are occupied by dichloromethane and aromatic guest molecules. The luminescent properties of crystalline 1 and 3 differ significantly.

Cepaic acid, a novel yellow xanthylium pigment from the dried outer scales of the yellow onion Allium cepa

Cepaic acid was isolated as a novel xanthylium yellow pigment from the dried outer scales of the yellow onion Allium cepa Linne. Its structure was elucidated on the basis of ESI-MS and 2D NMR spectroscopy as a 9-carboxy-1,3,6,8-tetrahydroxyxanthylium, which suggests that cepaic acid and other yellow pigments in the dried outer skin of onion were formed by the nucleophilic reaction of phloroglucinol derived from quercetin, a flavonol in onion scales, by autoxidation to glyoxylic acid. To our knowledge, this is the first report of such a pigment in yellow onion.

Highly dispersed platinum–carbon aerogel catalyst for polymer electrolyte membrane fuel cells

Platinum loaded carbon aerogel catalysts for application in polymer electrolyte membrane fuel cells have been synthesized from the alcoholic sol–gel reaction of phloroglucinol with furfural using propylene oxide as a reducing agent of platinum salt, followed by supercritical drying with carbon dioxide. Subsequent carbonization of the platinum–organic aerogels under a reducing gas flow produced platinum–carbon aerogels. X-ray diffraction and transmission electron microscopy analyses of the platinum–carbon aerogel catalysts indicate the formation of well-dispersed platinum nanoparticles having sizes of about 3 nm. Surface characterization of the platinum–carbon aerogel by X-ray photoelectron spectroscopy reveals that 60% of the platinum is present in its metallic state. Electrochemical characterization by hydrogen adsorption/desorption cyclic voltammetry and CO stripping voltammetry indicates that the electrochemical active surface areas of the platinum–carbon aerogel are comparable to those of commercial catalysts.

Noninvasive Evaluation of Intestinal Lactase with 4-Galactosylxylose: Comparison with 3- and 2-Galactosylxylose and Optimization of the Method in Rats

Urinary excretion of D-xylose by suckling rats after ingestion of a mixture of 4-, 3-, and 2-galactosylxyloses reflects lactase activity in vivo. We aimed to select the most convenient of these disaccharides for detecting changes of the enzyme activity in vivo and to optimize the method. 4-, 3-, and 2-galactosylxyloses were synthesized and purified, then orally administered to suckling rats of different ages. D-Xylose was measured colorimetrically by the phloroglucinol reaction in urine and plasma. Lactase activity was determined in extracts of small intestine mucosa with lactose, galactosylxyloses, and phlorizin as substrates. D-Xylose appeared in the urine in a dose-dependent manner after ingestion of any of the 3 galactosylxylose disaccharides. Correlation between D-xylose elimination and intestinal lactase activity was highest with 4-galactosylxylose (r = 0.97; n = 24), lower with 2-galactosylxylose (r = 0.89; n = 24), and lowest with 3-galactosylxylose (r = 0.34; n = 23). The kinetic properties of intestinal lactase accounted for these differences. D-Xylose concentration in plasma after administration of 4-galactosylxylose also correlated with lactase activity (r = 0.93; n = 33). 4-Galactosylxylose is the most suitable compound for the evaluation of lactase activity in vivo. Measurement of the derived D-xylose in either urine or blood gives an estimate of the total lactose digestive capacity of the small intestine. The optimized method holds promise for development of a simple, low-cost, and reliable new test for the noninvasive diagnosis of hypolactasia.

Phenylboronic Acid Mediated Triple Condensation Reactions of Phloroglucinol and Unsaturated Carbonyl Compounds.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Phenylboronic Acid Mediated Triple Condensation Reactions of Phloroglucinol and Unsaturated Carbonyl Compounds

[reaction: see text] A remarkable phenylboronic acid mediated triple condensation reaction of phloroglucinol (1,3,5-trihydroxybenzene) with a series of alpha,beta-unsaturated carbonyl compounds is reported. This experimentally simple reaction afforded novel C3-symmetric 2H-chromene derivatives. These derivatives represent structural analogues of the natural product xyloketal A, which has been reported to be a potent inhibitor of acetylcholine esterase.