The technique for preparing phenol formaldehyde resin from phenolated wood (PWF) and its characters were studied and analyzed. Poplar (Populus spp.) wood meal was liquefied by phenol in the presence of sulfuric acid a...The technique for preparing phenol formaldehyde resin from phenolated wood (PWF) and its characters were studied and analyzed. Poplar (Populus spp.) wood meal was liquefied by phenol in the presence of sulfuric acid as a catalyst. After the liquefied products were cooled, alkaline catalyst and formaldehyde were added. The mixture was kept at (60?) C for 1h and then was heated to (85?) C for 1h. The influence of molar ratio of formaldehyde to phenol (F/P) was investigated. The results showed when the molar ratio of formaldehyde to phenol was over 1.8, the PWF adhesives had high bond quality, bond durability and extremely low aldehydes emissions.展开更多
Single component rare earth phenolates substituted by various alkyl groups have been prepared and the correlation between the aryloxides＇ structure and catalytic activity in the ring-opening polymerization of D,L-lac...Single component rare earth phenolates substituted by various alkyl groups have been prepared and the correlation between the aryloxides＇ structure and catalytic activity in the ring-opening polymerization of D,L-lactide has also been investigated.The catalytic activity of all rare earth aryloxides,characteristics of the ring-opening polymerization as well as polymerization kinetics and mechanism were investigated.The results showed that both phenolates＇ catalytic activities and polymerization characteristics changed regularly,keeping in good concordance with variations in substitutents＇ number on phenol and structure of aryloxide ligands.The stronger ability of electron-donation of alkyl groups,the higher catalytic activity.Moreover,the more numbers of substituted alkyl on phenyl ring,the higher catalytic activity.The analyses of polymer ends revealed that the polymerization proceeded via a coordination-acyl-oxygen bond cleavage-insertion mechanism.展开更多
The neodymium chloride complex[Nd（ONN＇O）Cl（THF）]2 supported by amine-bis（phenolate） ligand was synthesized by the metathesis reaction of anhydrous NdCl3 with Li2（ONN＇O）[H2ONN＇O = Me2NCH2CH2N（CH2-3-Bu2^t-5-...The neodymium chloride complex[Nd（ONN＇O）Cl（THF）]2 supported by amine-bis（phenolate） ligand was synthesized by the metathesis reaction of anhydrous NdCl3 with Li2（ONN＇O）[H2ONN＇O = Me2NCH2CH2N（CH2-3-Bu2^t-5-Me-C6H2OH）2]in high yield.X-ray structural determination shows[Nd（ONN＇O）Cl（THF）]2 complex consists of two seven-coordinate neodymium centers linked throughμ-Cl bridges.And this complex was successfully used to initiate the ring-opening polymerization（ROP） ofε-caprolactone.展开更多
Two vanadium complexes of schiff base vith rich phenolate oxygen,o-(?)-salicylideneamino- methylphenol,had been synthesized and characterized.One is a V(Ⅳ)complex with an interaction via vanadyl oxygen and the other ...Two vanadium complexes of schiff base vith rich phenolate oxygen,o-(?)-salicylideneamino- methylphenol,had been synthesized and characterized.One is a V(Ⅳ)complex with an interaction via vanadyl oxygen and the other is a novel dinuclear V(V,V)complex with an oxo bridge.The conversion between the two complexes had been discussed.展开更多
Two d10 metal complexes Zn（NCS）2（C14HI3NO2）2 （1） and [Cd（NO3）2（CI4HI3NO2）2]. 4H20 （2） assembled by 2-methoxy-6-（phenyliminiomethyl） phenolate ligand （C14H13NO2, HL） have been synthesized and characteri...Two d10 metal complexes Zn（NCS）2（C14HI3NO2）2 （1） and [Cd（NO3）2（CI4HI3NO2）2]. 4H20 （2） assembled by 2-methoxy-6-（phenyliminiomethyl） phenolate ligand （C14H13NO2, HL） have been synthesized and characterized by elemental analysis, IR and TG The single-crystal X-ray diffraction studies demonstrated that complex 1 crystallizes in monoclinic, P21/c space group with a = 17.321（7）, b = 11.781（0）, c = 15.593（2） A, fl = 110.273（6）°, V = 2984.95 A3, Z = 4, C30H26N404SzZn, Mr = 636.04, F（000） = 1312, Dc = 1.415 g/cm3,μ（MoKa） = 1.004 mm＂1, the final R = 0.0403 and wR = 0.0900 for 21441 observed reflections with I 〉 20（/）. Complex 2 is of monoclinic system, space group C2/c with a = 16.7767（2）, b = 10.8989（2）, c = 17.4928（2） A, fl = 90.614（9）°, V= 3198.37 A3, Z = 4, C28H34N4O14Cd, Mr= 731.25, F（000） = 1528, Dc = 1.568 g＇cm^-3, μ（MoKa） = 0.757 mm-1, the final R = 0.0361 and wR = 0.0857 for 19811 observed reflections with I 〉 2σ（I）. The two complexes were formed by Schiff base 2-methoxy-6-（phenyliminiomethyl） phenolate ligand and formed a 3D supramolecular architecture by π-πstacking interactions. Moreover, the complexes are luminescent in the solid state. These observations indicate that the complexes are promising system for the development of potential photoactive materials.展开更多
Three new chiral monoanionic [ON] ancillary phenolate ligands with varying pendant arms have been synthesized in moderate to high yields (50% - 85%) via Mannich-type condensation reaction of chiral substituted phenol,...Three new chiral monoanionic [ON] ancillary phenolate ligands with varying pendant arms have been synthesized in moderate to high yields (50% - 85%) via Mannich-type condensation reaction of chiral substituted phenol, formaldehyde and (+)-bis-[(R)-1-phenylethyl]amine. These new organic compounds were fully characterized via nuclear magnetic resonance spectroscopy (1H and 13C) and elemental analysis. The newly synthesized ligands are suitable candidates for metal-catalyzed ring-opening of lactones and asymmetric catalysis.展开更多
Wood of Chinese fir and poplar were liquefied in phenol at 150℃ and atmospheric pressure. The liquefied wood were reacted with formaldehyde to synthesize the liquefied wood-based resin. The factors affecting the resi...Wood of Chinese fir and poplar were liquefied in phenol at 150℃ and atmospheric pressure. The liquefied wood were reacted with formaldehyde to synthesize the liquefied wood-based resin. The factors affecting the resinification and the properties of new resin were investigated. The results show that the formaldehyde/liquefied wood molar ratio, reaction temperature, reaction time and sodium hydroxide/liquefied wood molar ratio have important influence on the resin characteristics. With the increase of formaldehyde/liquefied wood molar ratio, the yield of resin increases, and the flee phenol content of resins decreases, showing that the resinification of liquefied wood is more complete at higher formaldehyde/liquefied wood molar ratios. The reaction temperature on the viscosity of the liquefied resin has considerable effect; the viscosity of resin increased with increasing reaction temperature, and the amount of liquefied poplar resin increased more quickly than that of liquefied Chinese fir resin. The resinification time also has obvious influence on the viscosity of resin; the viscosity of liquefied poplar resin is more sensitive to resinification time compared with that of liquefied Chinese fir. The amount of sodium hydroxide can improve the water miscibility of liquefied wood resin. The optimum sodium hydroxide/liquefied wood molar ratio for preparation of liquefied wood-based resins exceeds 0.4.展开更多
A potential tetradentate monoanionic N_(2)O_(2) chelator,HL,derived from the condensation of o-vanillin and N,N-dimethylethylenediammine,has been reacted with nickel perchlorate and sodium azide to yield the dinuclear...A potential tetradentate monoanionic N_(2)O_(2) chelator,HL,derived from the condensation of o-vanillin and N,N-dimethylethylenediammine,has been reacted with nickel perchlorate and sodium azide to yield the dinuclear Ni(Ⅱ)complex[Ni(L)(μ_(1,1)-N_(3))Ni(L)(OH_(2))_(2)]·ClO_(4)(1),where L=Me_(2)N(CH_(2))_(2)NvCH-C_(6)H_(3)(O^(-))-(OCH_(3)).The complex has been characterized by X-ray diffraction analysis and different spectroscopic techniques.The coordination geometry around the Ni(II)centres is a distorted octahedron,with the azide ligand and the phenolato oxygen atom bridging inμ1,1 andμ2 mode,respectively.The EPR spectra,recorded at liquid nitrogen temperature(77 K)and room temperature(298 K),show g factors of 2.080 and 2.085,in agreement with the structure determined by X-ray diffraction analysis.The VTM study confirms that there are ferromagnetic interactions between the bridging binuclear Ni(II)ions(S=1).The evaluation of cytotoxic effects on different human cancer cell lines(A-549,MCF-7 and CaCo-2)suggests that both the ligand and complex 1 have potential anticancer properties.Furthermore,they also exhibit anti-mycobacterial activity against M.tuberculosis H37Rv(ATCC 27294)and M.tuberculosis H37Ra(ATCC 25177)strains.Molecular docking of HL with the enoyl acyl carrier protein reductase of M.tuberculosis H37R_(v)(PDB ID:4U0K)has been examined,showing that HL forms two hydrogen bonds with Lys165(1.94 and 2.53A)in its best docked pose.展开更多
A series of rare-earth(RE)metal complexes[RE=La(1,5,6),Nd(2),Sm(3),Y(4)]bearing polydentate N’-(2-aminoethyl)-N,N-dimethyl-1,2-ethylenediamine bridged-tris(phenolto)ligands were synthesized and characterized.The acti...A series of rare-earth(RE)metal complexes[RE=La(1,5,6),Nd(2),Sm(3),Y(4)]bearing polydentate N’-(2-aminoethyl)-N,N-dimethyl-1,2-ethylenediamine bridged-tris(phenolto)ligands were synthesized and characterized.The activity of complexes 1-6 for catalysing the cycloaddition reaction of CO_(2) and epoxides was studied,and the lanthanum complex 1 showed the highest activity.Under the conditions of 1 bar CO_(2) and 25℃,lanthanum complex 1 catalysed the reaction of 18 mono-substituted epoxides,generating cyclic carbonates in 50-99% yields.More importantly,it also catalysed reactions of 6 di-substituted epoxides under ambient conditions(1 bar CO_(2) and 25℃),and generated cyclic carbonates in 85-99% yields.This lanthanum complex is the first catalyst capable of converting di-substituted epoxides into internal cyclic carbonates under ambient conditions.Kinetic study was conducted to determine rate orders and Gibbs activation energy.A DFT study proved that poly(phenolto)ligands play vital roles in product dissociation.展开更多
Herein,we report the application of four amino-tris(phenolate)-based metal complexes incorporating Ti(IV)or Zr(IV)centres(2a-3b)as homogeneous catalysts for the conversion of CO_(2)and epoxides into cyclic carbonates....Herein,we report the application of four amino-tris(phenolate)-based metal complexes incorporating Ti(IV)or Zr(IV)centres(2a-3b)as homogeneous catalysts for the conversion of CO_(2)and epoxides into cyclic carbonates.The four complexes were synthesised,characterised and then evaluated in combination with tetrabutylammo-nium iodide,bromide or chloride as binary catalytic systems for the reaction of CO_(2)with 1,2-epoxyhexane as epoxide substrate at 12 bar CO_(2)pressure and 90?C for 2 h.The catalytic systems comprising the two Ti(IV)complexes(2a and 2b)showed similar performance.One notable exception was the catalytic system consisting of titanium complex 2b,bearing an axial Cl-ligand,and tetrabutylammonium chloride,which displayed higher catalytic activity compared to other titanium-based systems.Even higher activity was achieved with Zr(IV)complex 3a,bearing an axial isopropoxide ligand,which reached turnover numbers(TON metal)up to 1920 for the reaction of CO_(2)with 1,2-epoxyhexane at 12 bar CO_(2)pressure and 90?C for 2 h.This performance is comparable with that of state-of-the-art catalysts for this reaction.The catalytic system consisting of complex 3a and tetra-butylammonium bromide was explored further by investigating its applicability with a broad substrate scope,achieving quantitative conversion of several epoxides with CO_(2)into cyclic carbonate products at 90?C and 12 bar CO_(2)pressure for 18 h.The selectivity towards the cyclic carbonate products was?98%for all studied terminal epoxides and?80%for all examined cyclohexene-type epoxides.展开更多
Four divalent lanthanide complexes Sm(ArO)2 -(THF)4) Yb(ArO)2(THF)3, Eu(ArO)2(THF)3 (ArO=2,6-di-tert-butyl-4-methylphenolate) and (ButCp)2Sm(THF)2 were synthesized. Their catalytic activities on the polymerization of ...Four divalent lanthanide complexes Sm(ArO)2 -(THF)4) Yb(ArO)2(THF)3, Eu(ArO)2(THF)3 (ArO=2,6-di-tert-butyl-4-methylphenolate) and (ButCp)2Sm(THF)2 were synthesized. Their catalytic activities on the polymerization of acrylonitrile were studied. The catalytic activities were influenced by the central metal ions involved. The catalytic activities of these divalent lanthanide complexes can be greatly increased by adding NaOC6H2-2,6-But2-4-Me, NaOC6H4-4-But, or NaOC10H6-2-Me. The amount of additive has apparent effect on the catalytic activity, but the additive has no effect on the tacticity of the resulting polyacryloni-trile.展开更多
The synthesis and characterization of aluminum alkoxide and alkyl complexes stabilized by piperazidine- bridged bis（phenolate） ligands are described. Treatment of ligand precursors Hz[ONNO]^1 {Hz[ONNO]^1= 1,4-bis（2...The synthesis and characterization of aluminum alkoxide and alkyl complexes stabilized by piperazidine- bridged bis（phenolate） ligands are described. Treatment of ligand precursors Hz[ONNO]^1 {Hz[ONNO]^1= 1,4-bis（2-hydroxy-3-tert-butyl-5-methylbenzyl）piperazidine} and Hz[ONNO]2 {H2[ONNO]2=1,4-bis（2-hydroxy3,5-di-tert-butylbenzyl）piperazidine} with A1Et2（OCH2Ph） and A1Etz（OPr-i）, which were generated in situ by the reactions of AIEt3 with equivalent of the corresponding alcohols, in a 1： 1 molar ratio in THF gave the corresponding aluminum alkoxide complexes [ONNO]IAI（OCH2Ph） （1） and [ONNO]2Al（OPr-i） （2）, respectively. The reaction of H2[ONNO]^1 with A1Etz（OCHzPh） in a 1 ： 2 molar ratio in THF afforded a mixture of monometallic aluminum ethyl complex [ONNO] 1A1Et （3） and complex 1, which can be isolated by stepwise crystallization. Similarly, Hz[ONNO]2 reacted with A1Etz（OPr-0 in a 1： 2 molar ratio in THF to give a mixture of aluminum ethyl complex [ONNO]2AlEt （4） and complex 2. Complexes 1 and 2 were also available via treatment of complexes 3 and 4 with 1 equiv, of benzyl alcohol and isopropyl alcohol, respectively. All of these complexes were fully characterized including X-ray structural determination. It was found that complexes 1 to 4 can initiate the ring-opening polymerization of e-caprolactone, and complexes 1 and 2 showed higher catalytic activity in comparison with com- plexes 3 and 4.展开更多
A series of neutral bimetallic lanthanide aryloxides p-C6H4[OLnL(THF)n]2 [Ln = Y(1), Yb(2), Sm(3)(n = 1) and La(4)(n = 2), L = Me2NCH2CH2N{CH2-(2-O–C6H2–tBu2-3,5)}2] and alkoxides p-C6H4CH2[OLnL(THF)]2 [Ln = Y(5), Y...A series of neutral bimetallic lanthanide aryloxides p-C6H4[OLnL(THF)n]2 [Ln = Y(1), Yb(2), Sm(3)(n = 1) and La(4)(n = 2), L = Me2NCH2CH2N{CH2-(2-O–C6H2–tBu2-3,5)}2] and alkoxides p-C6H4CH2[OLnL(THF)]2 [Ln = Y(5), Yb(6)] supported by an amine-bridged bis(phenolate) ligand have been synthesized through one-pot reactions of Ln(C5H5)3(THF), LH2 with p-benzenediol and 1,4-benzenedimethanol, respectively. All complexes have been fully characterized by elemental analyses, single-crystal X-ray diffraction analysis, and IR and multi-nuclear NMR spectroscopy(in the cases of 1, 4 and 5). Study of their catalytic behavior revealed that, in general, all complexes are efficient initiators for the polymerization of rac-lactide(LA) and rac-β-butyrolactone(BBL), except for 3 and 4 in the case of BBL. The influence imposed by lanthanides of different ionic radii and initiating groups of different structures on the activity, controllability, and stereoselectivity of polymerization were systematically studied and compared. Highly heterotactic PLA(Pr up to 0.99) and syndiotactic PHB(Pr ≈ 0.81) with high molecular weight and narrow polydispersity formed and were automatically capped with hydroxyl functionality at both ends.展开更多
Two rosamine-based pH probes 1a and 1b with pyronine-phenol skeleton were designed and synthesized by a simple one-step reaction, pH titration experiments showed that probes 1a and 1b exhibit near OFF-ON fluorescence ...Two rosamine-based pH probes 1a and 1b with pyronine-phenol skeleton were designed and synthesized by a simple one-step reaction, pH titration experiments showed that probes 1a and 1b exhibit near OFF-ON fluorescence responses around 550--750 nm towards the hydrogen ions. The pKa of the probe 1a is 8.29, while that of the probe lb increases to 12.1 because of the hydrogen bond inside it. Selective and competitive experiments indicated that both common ions and amino acids did not interfere their emission with hydrogen ions. Moreover, confocal fluorescent imaging showed that the probe la could be served as mitochondria biomarker in HeLa and Ges-1 cells.展开更多
Lignin-derived oxygenated aromatics,particularly phenols and aromatic ethers obtained through depolymerization,represent promising feedstocks for synthesizing high-density and high-heat-sink aviation fuels via alkylat...Lignin-derived oxygenated aromatics,particularly phenols and aromatic ethers obtained through depolymerization,represent promising feedstocks for synthesizing high-density and high-heat-sink aviation fuels via alkylation-hydrogenation processes.This study systematically evaluates the catalytic performance of various zeolites(Hβ,HZSM-5,MCM-41 and HUSY)in the alkylation reaction of phenol with cyclohexanol.Characterization results demonstrate that HUSY zeolite showed superior catalytic activity compared to other zeolites,attributable to its favorable pore architecture and well-balanced acid site distribution that synergistically facilitate molecular diffusion and catalytic transformations.To further enhance the catalytic properties,HUSY zeolite was modified with citric acid at various concentrations and compared with those treated with NaOH and oxalic acid.The results revealed that citric acid treatment preserved the crystallinity of the zeolite while modulating its acid distribution and pore structure.All modified zeolites enhanced phenol alkylation activity.Notably,the HUSY-0.5M catalyst,which exhibited the highest medium-strong acid to total acid ratio,achieved superior catalytic performance,80.4%conversion of phenol and 99.6%selectivity for alkylation products.The catalyst also exhibited high activity in the alkylation of various lignin-derived compounds,demonstrating its broad applicability.This work provides a new strategy for the valorization of lignin-derived phenols into high-value fuel precursors through alkylation.展开更多
Objective Exposure to mixtures of environmental chemicals may influence asthma outcomes;however,the evidence remains equivocal.This study aimed to assess the association between mixed exposure to phenols and parabens ...Objective Exposure to mixtures of environmental chemicals may influence asthma outcomes;however,the evidence remains equivocal.This study aimed to assess the association between mixed exposure to phenols and parabens and asthma outcomes in adults and to explore the mediating role of body mass index(BMI).Methods Based on data from the National Health and Nutrition Examination Survey(NHANES,2013–2016),this study used multivariate generalized linear regression and weighted quantile sum(WQS)regression models to evaluate the associations between individual and joint exposure to phenols and parabens and asthma outcomes.These associations were further analyzed and stratified according to age and BMI.A mediation effect analysis was used to assess the role of BMI in this association.Results This study included 2,556 adults,of whom 400(15.7%)were diagnosed with asthma.After adjusting for all covariates,a significant positive correlation was observed between the chemical mixture and asthma,with an odds ratio of 1.33(95%confidence interval,1.06–1.68).Among the eight phenols and parabens,bisphenol F(BPF),propylparaben(PrP),and bisphenol S(BPS)were the major contributors.Additionally,BMI mediated 15.5%of the association between BPF exposure and asthma.Conclusion In this cross-sectional study,mixed exposure to phenols and parabens was significantly associated with asthma outcomes,with BPF,PrP,and BPS identified as the primary contributing chemicals.This study provides valuable insights into the association between mixed chemical exposure and asthma as well as potential control pathways.展开更多
Mexican oregano(Lippia graveolens Kunth)is an aromatic species of high culinary and medicinal relevance.In Mexico,more than 40 taxa with characteristic aroma and flavor are commercially recognized as oregano,with L.gr...Mexican oregano(Lippia graveolens Kunth)is an aromatic species of high culinary and medicinal relevance.In Mexico,more than 40 taxa with characteristic aroma and flavor are commercially recognized as oregano,with L.graveolens being the most widely distributed and economically important.Despite its relevance,few domesticated or semi-domesticated cultivars exist,and wild populations remain the main source of raw material,raising concerns regarding sustainability and quality standardization.The essential oil and oleoresins of L.graveolens possess recognized bioactivity,including antioxidant,antifungal,antibacterial,and anti-inflammatory properties,largely attributed to phenolic compounds such as thymol and carvacrol.Given the increasing global demand for natural bioactives and functional foods,optimizing cultivation practices is essential to enhance both the yield and phytochemical quality of this species.This study evaluated the effect of organic fertilization(0,5,10,and 15 t ha^(−1)of vermicompost)on the phenolic profile,flavonoid content,and antioxidant capacity of oregano oleoresin obtained from a semi-domesticated population across three harvests.The highest phenolic concentration(≈500 mg GAE g^(−1)extract)and greatest antioxidant activity(ABTS>3.5×10^(5)μmol TE g^(−1)extract)were observed at the 5 t ha^(−1)dose during the second harvest.Flavonoid content peaked in the third harvest(480-620 mg QE g^(−1)extract),whereas the unfertilized control exhibited the highest DPPH activity in the first harvest.Overall,the results indicate that vermicompost dosage and harvest timing substantially influence the functional quality of L.graveolens.Moderate organic fertilization,particularly 5 t ha^(−1),enhances the biosynthesis of bioactive secondary metabolites,underscoring its potential for sustainable production systems.展开更多
Pomegranate residues(PRs),namely pomegranate peels and seeds remaining after juice extraction,constitute a significant agro-industrial residue in Greece.Despite their ample content in carbon sources and bioactive comp...Pomegranate residues(PRs),namely pomegranate peels and seeds remaining after juice extraction,constitute a significant agro-industrial residue in Greece.Despite their ample content in carbon sources and bioactive compounds,PRs are largely unexploited,with their management being an increasing concern for the pome-granate processing industry.The objective of this study was the development and characterization of a bio-process aiming at the biotechnological valorization of PRs for ethanol production.Specifically,a stepwise investigation was conducted,including(i)the production and chemical characterization of extracts/hydrolysates from PRs using distinct pretreatments not involving organic solvents or enzymatic hydrolysis;(ii)the assessment of the exploitability of a selected hydrolysate as fermentation feedstock using Saccharomyces cerevisiae;and(iii)the advancement of the bioprocess through the joined utilization in the fermentation substrate of PRs and seeded raisins(SRs),another important agro-industrial residue in Greece.The finally developed substrate,comprising a mixture of PRs/SRs extracts at concentrations 60/40%v/v,was used in three fermentation trials,and the fermentation process was quantitatively described using the Aiba model.The developed bioprocess resulted in satisfactorily high bioethanol production with the maximum attained concentration being 50.0±0.6 g/L.The maximum specific growth rate(μ_(max))of S.cerevisiae was estimated to be 0.1351/h and the bioethanol yield(Y_(ps)),namely the amount of produced ethanol/amount of consumed reducing sugars,was estimated to be 0.423 g/g.Hence,PRs can be efficiently used in the development of a fermentation substrate for bioethanol production,providing an economic and environmentally sustainable alternative to conventional feedstocks.展开更多
Poly(phenylene oxide)(PPO)exhibits excellent dielectric properties,making it an ideal substrate for high-frequency,high-speed copper-clad laminates.The phenolic hydroxyl group at the end of PPO plays a key role in its...Poly(phenylene oxide)(PPO)exhibits excellent dielectric properties,making it an ideal substrate for high-frequency,high-speed copper-clad laminates.The phenolic hydroxyl group at the end of PPO plays a key role in its reactivity.Accurately quantifying the phenolic hydroxyl content in PPO is essential but challenging.In this study,we proposed a method for measuring the phenolic hydroxyl content of PPO using differential UV absorption spectroscopy.In alkaline solutions,the phenolic hydroxyl in PPO completely ionizes to form phenoxide ions,leading to a significant increase in UV absorbance at approximately 250 and 300 nm.Notably,the differential UV absorbance at approximately 300 nm was directly proportional to the phenolic hydroxyl concentration.Using 2,6-dimethylphenol as a standard,a calibration curve was established to relate the phenolic hydroxyl concentration to differential UV absorbance at approximately 300 nm,providing a precise and straightforward method for phenolic hydroxyl quantification in PPO with distinct advantages over conventional techniques.展开更多
By means of gel permeation chromatography analysis, the molecular weight of liquefied wood under different reaction conditions was investigated to trace the change in the structural characteristics of the liquefied wo...By means of gel permeation chromatography analysis, the molecular weight of liquefied wood under different reaction conditions was investigated to trace the change in the structural characteristics of the liquefied wood. The insoluble residues were analyzed by Fourier transform infrared to investigate the liquefaction order of three main wood components. The results indicate that both reaction temperature and reaction time could affect the molecular characteristics of the liquefied wood obtained. The mo...展开更多
文摘The technique for preparing phenol formaldehyde resin from phenolated wood (PWF) and its characters were studied and analyzed. Poplar (Populus spp.) wood meal was liquefied by phenol in the presence of sulfuric acid as a catalyst. After the liquefied products were cooled, alkaline catalyst and formaldehyde were added. The mixture was kept at (60?) C for 1h and then was heated to (85?) C for 1h. The influence of molar ratio of formaldehyde to phenol (F/P) was investigated. The results showed when the molar ratio of formaldehyde to phenol was over 1.8, the PWF adhesives had high bond quality, bond durability and extremely low aldehydes emissions.
基金Funded by the Natural Science Foundation of Shanxi Province (No.2006011069)the Opening Foundation of Key Laboratory of Shanxi Province (No.2009011059-7)
文摘Single component rare earth phenolates substituted by various alkyl groups have been prepared and the correlation between the aryloxides＇ structure and catalytic activity in the ring-opening polymerization of D,L-lactide has also been investigated.The catalytic activity of all rare earth aryloxides,characteristics of the ring-opening polymerization as well as polymerization kinetics and mechanism were investigated.The results showed that both phenolates＇ catalytic activities and polymerization characteristics changed regularly,keeping in good concordance with variations in substitutents＇ number on phenol and structure of aryloxide ligands.The stronger ability of electron-donation of alkyl groups,the higher catalytic activity.Moreover,the more numbers of substituted alkyl on phenyl ring,the higher catalytic activity.The analyses of polymer ends revealed that the polymerization proceeded via a coordination-acyl-oxygen bond cleavage-insertion mechanism.
基金the financial supports of the National Natural Science Foundation of China (No.20774078)the Special Funds for Major Basic Research Projects(No.2005CB623802)Scientific Research Foundation for Returned Scholars,Ministry of Education of China
文摘The neodymium chloride complex[Nd（ONN＇O）Cl（THF）]2 supported by amine-bis（phenolate） ligand was synthesized by the metathesis reaction of anhydrous NdCl3 with Li2（ONN＇O）[H2ONN＇O = Me2NCH2CH2N（CH2-3-Bu2^t-5-Me-C6H2OH）2]in high yield.X-ray structural determination shows[Nd（ONN＇O）Cl（THF）]2 complex consists of two seven-coordinate neodymium centers linked throughμ-Cl bridges.And this complex was successfully used to initiate the ring-opening polymerization（ROP） ofε-caprolactone.
文摘Two vanadium complexes of schiff base vith rich phenolate oxygen,o-(?)-salicylideneamino- methylphenol,had been synthesized and characterized.One is a V(Ⅳ)complex with an interaction via vanadyl oxygen and the other is a novel dinuclear V(V,V)complex with an oxo bridge.The conversion between the two complexes had been discussed.
基金supported by the Natural Science Foundation of Zhejiang Province (LY12B01003)
文摘Two d10 metal complexes Zn（NCS）2（C14HI3NO2）2 （1） and [Cd（NO3）2（CI4HI3NO2）2]. 4H20 （2） assembled by 2-methoxy-6-（phenyliminiomethyl） phenolate ligand （C14H13NO2, HL） have been synthesized and characterized by elemental analysis, IR and TG The single-crystal X-ray diffraction studies demonstrated that complex 1 crystallizes in monoclinic, P21/c space group with a = 17.321（7）, b = 11.781（0）, c = 15.593（2） A, fl = 110.273（6）°, V = 2984.95 A3, Z = 4, C30H26N404SzZn, Mr = 636.04, F（000） = 1312, Dc = 1.415 g/cm3,μ（MoKa） = 1.004 mm＂1, the final R = 0.0403 and wR = 0.0900 for 21441 observed reflections with I 〉 20（/）. Complex 2 is of monoclinic system, space group C2/c with a = 16.7767（2）, b = 10.8989（2）, c = 17.4928（2） A, fl = 90.614（9）°, V= 3198.37 A3, Z = 4, C28H34N4O14Cd, Mr= 731.25, F（000） = 1528, Dc = 1.568 g＇cm^-3, μ（MoKa） = 0.757 mm-1, the final R = 0.0361 and wR = 0.0857 for 19811 observed reflections with I 〉 2σ（I）. The two complexes were formed by Schiff base 2-methoxy-6-（phenyliminiomethyl） phenolate ligand and formed a 3D supramolecular architecture by π-πstacking interactions. Moreover, the complexes are luminescent in the solid state. These observations indicate that the complexes are promising system for the development of potential photoactive materials.
文摘Three new chiral monoanionic [ON] ancillary phenolate ligands with varying pendant arms have been synthesized in moderate to high yields (50% - 85%) via Mannich-type condensation reaction of chiral substituted phenol, formaldehyde and (+)-bis-[(R)-1-phenylethyl]amine. These new organic compounds were fully characterized via nuclear magnetic resonance spectroscopy (1H and 13C) and elemental analysis. The newly synthesized ligands are suitable candidates for metal-catalyzed ring-opening of lactones and asymmetric catalysis.
基金Supported by the Key Research Program Foundation, Ministry of Education of China (Grant No. 02021)and the National Science Foundation of China (Grant No. 30471351)
文摘Wood of Chinese fir and poplar were liquefied in phenol at 150℃ and atmospheric pressure. The liquefied wood were reacted with formaldehyde to synthesize the liquefied wood-based resin. The factors affecting the resinification and the properties of new resin were investigated. The results show that the formaldehyde/liquefied wood molar ratio, reaction temperature, reaction time and sodium hydroxide/liquefied wood molar ratio have important influence on the resin characteristics. With the increase of formaldehyde/liquefied wood molar ratio, the yield of resin increases, and the flee phenol content of resins decreases, showing that the resinification of liquefied wood is more complete at higher formaldehyde/liquefied wood molar ratios. The reaction temperature on the viscosity of the liquefied resin has considerable effect; the viscosity of resin increased with increasing reaction temperature, and the amount of liquefied poplar resin increased more quickly than that of liquefied Chinese fir resin. The resinification time also has obvious influence on the viscosity of resin; the viscosity of liquefied poplar resin is more sensitive to resinification time compared with that of liquefied Chinese fir. The amount of sodium hydroxide can improve the water miscibility of liquefied wood resin. The optimum sodium hydroxide/liquefied wood molar ratio for preparation of liquefied wood-based resins exceeds 0.4.
基金West Bengal DST,Kolkata,India for the grant(228/1(10)/(Sanc.)/ST/P/S&T/9G-16/2012).
文摘A potential tetradentate monoanionic N_(2)O_(2) chelator,HL,derived from the condensation of o-vanillin and N,N-dimethylethylenediammine,has been reacted with nickel perchlorate and sodium azide to yield the dinuclear Ni(Ⅱ)complex[Ni(L)(μ_(1,1)-N_(3))Ni(L)(OH_(2))_(2)]·ClO_(4)(1),where L=Me_(2)N(CH_(2))_(2)NvCH-C_(6)H_(3)(O^(-))-(OCH_(3)).The complex has been characterized by X-ray diffraction analysis and different spectroscopic techniques.The coordination geometry around the Ni(II)centres is a distorted octahedron,with the azide ligand and the phenolato oxygen atom bridging inμ1,1 andμ2 mode,respectively.The EPR spectra,recorded at liquid nitrogen temperature(77 K)and room temperature(298 K),show g factors of 2.080 and 2.085,in agreement with the structure determined by X-ray diffraction analysis.The VTM study confirms that there are ferromagnetic interactions between the bridging binuclear Ni(II)ions(S=1).The evaluation of cytotoxic effects on different human cancer cell lines(A-549,MCF-7 and CaCo-2)suggests that both the ligand and complex 1 have potential anticancer properties.Furthermore,they also exhibit anti-mycobacterial activity against M.tuberculosis H37Rv(ATCC 27294)and M.tuberculosis H37Ra(ATCC 25177)strains.Molecular docking of HL with the enoyl acyl carrier protein reductase of M.tuberculosis H37R_(v)(PDB ID:4U0K)has been examined,showing that HL forms two hydrogen bonds with Lys165(1.94 and 2.53A)in its best docked pose.
基金the National Natural Science Foundation of China(21871198)the Major Research Project of the Natural Science of the Jiangsu Higher Education Institutions(19KJA360005,19KJA320007)PAPD.
文摘A series of rare-earth(RE)metal complexes[RE=La(1,5,6),Nd(2),Sm(3),Y(4)]bearing polydentate N’-(2-aminoethyl)-N,N-dimethyl-1,2-ethylenediamine bridged-tris(phenolto)ligands were synthesized and characterized.The activity of complexes 1-6 for catalysing the cycloaddition reaction of CO_(2) and epoxides was studied,and the lanthanum complex 1 showed the highest activity.Under the conditions of 1 bar CO_(2) and 25℃,lanthanum complex 1 catalysed the reaction of 18 mono-substituted epoxides,generating cyclic carbonates in 50-99% yields.More importantly,it also catalysed reactions of 6 di-substituted epoxides under ambient conditions(1 bar CO_(2) and 25℃),and generated cyclic carbonates in 85-99% yields.This lanthanum complex is the first catalyst capable of converting di-substituted epoxides into internal cyclic carbonates under ambient conditions.Kinetic study was conducted to determine rate orders and Gibbs activation energy.A DFT study proved that poly(phenolto)ligands play vital roles in product dissociation.
文摘Herein,we report the application of four amino-tris(phenolate)-based metal complexes incorporating Ti(IV)or Zr(IV)centres(2a-3b)as homogeneous catalysts for the conversion of CO_(2)and epoxides into cyclic carbonates.The four complexes were synthesised,characterised and then evaluated in combination with tetrabutylammo-nium iodide,bromide or chloride as binary catalytic systems for the reaction of CO_(2)with 1,2-epoxyhexane as epoxide substrate at 12 bar CO_(2)pressure and 90?C for 2 h.The catalytic systems comprising the two Ti(IV)complexes(2a and 2b)showed similar performance.One notable exception was the catalytic system consisting of titanium complex 2b,bearing an axial Cl-ligand,and tetrabutylammonium chloride,which displayed higher catalytic activity compared to other titanium-based systems.Even higher activity was achieved with Zr(IV)complex 3a,bearing an axial isopropoxide ligand,which reached turnover numbers(TON metal)up to 1920 for the reaction of CO_(2)with 1,2-epoxyhexane at 12 bar CO_(2)pressure and 90?C for 2 h.This performance is comparable with that of state-of-the-art catalysts for this reaction.The catalytic system consisting of complex 3a and tetra-butylammonium bromide was explored further by investigating its applicability with a broad substrate scope,achieving quantitative conversion of several epoxides with CO_(2)into cyclic carbonate products at 90?C and 12 bar CO_(2)pressure for 18 h.The selectivity towards the cyclic carbonate products was?98%for all studied terminal epoxides and?80%for all examined cyclohexene-type epoxides.
基金the National Natural Science Foundation of China (Grant No. 20072027).
文摘Four divalent lanthanide complexes Sm(ArO)2 -(THF)4) Yb(ArO)2(THF)3, Eu(ArO)2(THF)3 (ArO=2,6-di-tert-butyl-4-methylphenolate) and (ButCp)2Sm(THF)2 were synthesized. Their catalytic activities on the polymerization of acrylonitrile were studied. The catalytic activities were influenced by the central metal ions involved. The catalytic activities of these divalent lanthanide complexes can be greatly increased by adding NaOC6H2-2,6-But2-4-Me, NaOC6H4-4-But, or NaOC10H6-2-Me. The amount of additive has apparent effect on the catalytic activity, but the additive has no effect on the tacticity of the resulting polyacryloni-trile.
文摘The synthesis and characterization of aluminum alkoxide and alkyl complexes stabilized by piperazidine- bridged bis（phenolate） ligands are described. Treatment of ligand precursors Hz[ONNO]^1 {Hz[ONNO]^1= 1,4-bis（2-hydroxy-3-tert-butyl-5-methylbenzyl）piperazidine} and Hz[ONNO]2 {H2[ONNO]2=1,4-bis（2-hydroxy3,5-di-tert-butylbenzyl）piperazidine} with A1Et2（OCH2Ph） and A1Etz（OPr-i）, which were generated in situ by the reactions of AIEt3 with equivalent of the corresponding alcohols, in a 1： 1 molar ratio in THF gave the corresponding aluminum alkoxide complexes [ONNO]IAI（OCH2Ph） （1） and [ONNO]2Al（OPr-i） （2）, respectively. The reaction of H2[ONNO]^1 with A1Etz（OCHzPh） in a 1 ： 2 molar ratio in THF afforded a mixture of monometallic aluminum ethyl complex [ONNO] 1A1Et （3） and complex 1, which can be isolated by stepwise crystallization. Similarly, Hz[ONNO]2 reacted with A1Etz（OPr-0 in a 1： 2 molar ratio in THF to give a mixture of aluminum ethyl complex [ONNO]2AlEt （4） and complex 2. Complexes 1 and 2 were also available via treatment of complexes 3 and 4 with 1 equiv, of benzyl alcohol and isopropyl alcohol, respectively. All of these complexes were fully characterized including X-ray structural determination. It was found that complexes 1 to 4 can initiate the ring-opening polymerization of e-caprolactone, and complexes 1 and 2 showed higher catalytic activity in comparison with com- plexes 3 and 4.
基金financial supported by the National Natural Science Foundation of China (20972108, 21174095, 21132002)a project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)the Qing Lan Project is gratefully acknowledged
文摘A series of neutral bimetallic lanthanide aryloxides p-C6H4[OLnL(THF)n]2 [Ln = Y(1), Yb(2), Sm(3)(n = 1) and La(4)(n = 2), L = Me2NCH2CH2N{CH2-(2-O–C6H2–tBu2-3,5)}2] and alkoxides p-C6H4CH2[OLnL(THF)]2 [Ln = Y(5), Yb(6)] supported by an amine-bridged bis(phenolate) ligand have been synthesized through one-pot reactions of Ln(C5H5)3(THF), LH2 with p-benzenediol and 1,4-benzenedimethanol, respectively. All complexes have been fully characterized by elemental analyses, single-crystal X-ray diffraction analysis, and IR and multi-nuclear NMR spectroscopy(in the cases of 1, 4 and 5). Study of their catalytic behavior revealed that, in general, all complexes are efficient initiators for the polymerization of rac-lactide(LA) and rac-β-butyrolactone(BBL), except for 3 and 4 in the case of BBL. The influence imposed by lanthanides of different ionic radii and initiating groups of different structures on the activity, controllability, and stereoselectivity of polymerization were systematically studied and compared. Highly heterotactic PLA(Pr up to 0.99) and syndiotactic PHB(Pr ≈ 0.81) with high molecular weight and narrow polydispersity formed and were automatically capped with hydroxyl functionality at both ends.
基金This work was financially supported by the National Natural Science Foundation of China （51273136）, Natural Science Fund of Jiangsu Province （BK20151262）, a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions （PAPD）, the Project of Scientific and Technologic Infrastructure of Suzhou （SZS201708） and Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions.
文摘Two rosamine-based pH probes 1a and 1b with pyronine-phenol skeleton were designed and synthesized by a simple one-step reaction, pH titration experiments showed that probes 1a and 1b exhibit near OFF-ON fluorescence responses around 550--750 nm towards the hydrogen ions. The pKa of the probe 1a is 8.29, while that of the probe lb increases to 12.1 because of the hydrogen bond inside it. Selective and competitive experiments indicated that both common ions and amino acids did not interfere their emission with hydrogen ions. Moreover, confocal fluorescent imaging showed that the probe la could be served as mitochondria biomarker in HeLa and Ges-1 cells.
基金Supported by National Key Research&Development Program of China (2022YFB4201800)Key Program of National Natural Science Foundation of China (52130610)。
文摘Lignin-derived oxygenated aromatics,particularly phenols and aromatic ethers obtained through depolymerization,represent promising feedstocks for synthesizing high-density and high-heat-sink aviation fuels via alkylation-hydrogenation processes.This study systematically evaluates the catalytic performance of various zeolites(Hβ,HZSM-5,MCM-41 and HUSY)in the alkylation reaction of phenol with cyclohexanol.Characterization results demonstrate that HUSY zeolite showed superior catalytic activity compared to other zeolites,attributable to its favorable pore architecture and well-balanced acid site distribution that synergistically facilitate molecular diffusion and catalytic transformations.To further enhance the catalytic properties,HUSY zeolite was modified with citric acid at various concentrations and compared with those treated with NaOH and oxalic acid.The results revealed that citric acid treatment preserved the crystallinity of the zeolite while modulating its acid distribution and pore structure.All modified zeolites enhanced phenol alkylation activity.Notably,the HUSY-0.5M catalyst,which exhibited the highest medium-strong acid to total acid ratio,achieved superior catalytic performance,80.4%conversion of phenol and 99.6%selectivity for alkylation products.The catalyst also exhibited high activity in the alkylation of various lignin-derived compounds,demonstrating its broad applicability.This work provides a new strategy for the valorization of lignin-derived phenols into high-value fuel precursors through alkylation.
基金supported by the National Natural Science Foundation of China(No.22276017)the Beijing Natural Science Foundation(Nos.7232236 and 7244455).
文摘Objective Exposure to mixtures of environmental chemicals may influence asthma outcomes;however,the evidence remains equivocal.This study aimed to assess the association between mixed exposure to phenols and parabens and asthma outcomes in adults and to explore the mediating role of body mass index(BMI).Methods Based on data from the National Health and Nutrition Examination Survey(NHANES,2013–2016),this study used multivariate generalized linear regression and weighted quantile sum(WQS)regression models to evaluate the associations between individual and joint exposure to phenols and parabens and asthma outcomes.These associations were further analyzed and stratified according to age and BMI.A mediation effect analysis was used to assess the role of BMI in this association.Results This study included 2,556 adults,of whom 400(15.7%)were diagnosed with asthma.After adjusting for all covariates,a significant positive correlation was observed between the chemical mixture and asthma,with an odds ratio of 1.33(95%confidence interval,1.06–1.68).Among the eight phenols and parabens,bisphenol F(BPF),propylparaben(PrP),and bisphenol S(BPS)were the major contributors.Additionally,BMI mediated 15.5%of the association between BPF exposure and asthma.Conclusion In this cross-sectional study,mixed exposure to phenols and parabens was significantly associated with asthma outcomes,with BPF,PrP,and BPS identified as the primary contributing chemicals.This study provides valuable insights into the association between mixed chemical exposure and asthma as well as potential control pathways.
文摘Mexican oregano(Lippia graveolens Kunth)is an aromatic species of high culinary and medicinal relevance.In Mexico,more than 40 taxa with characteristic aroma and flavor are commercially recognized as oregano,with L.graveolens being the most widely distributed and economically important.Despite its relevance,few domesticated or semi-domesticated cultivars exist,and wild populations remain the main source of raw material,raising concerns regarding sustainability and quality standardization.The essential oil and oleoresins of L.graveolens possess recognized bioactivity,including antioxidant,antifungal,antibacterial,and anti-inflammatory properties,largely attributed to phenolic compounds such as thymol and carvacrol.Given the increasing global demand for natural bioactives and functional foods,optimizing cultivation practices is essential to enhance both the yield and phytochemical quality of this species.This study evaluated the effect of organic fertilization(0,5,10,and 15 t ha^(−1)of vermicompost)on the phenolic profile,flavonoid content,and antioxidant capacity of oregano oleoresin obtained from a semi-domesticated population across three harvests.The highest phenolic concentration(≈500 mg GAE g^(−1)extract)and greatest antioxidant activity(ABTS>3.5×10^(5)μmol TE g^(−1)extract)were observed at the 5 t ha^(−1)dose during the second harvest.Flavonoid content peaked in the third harvest(480-620 mg QE g^(−1)extract),whereas the unfertilized control exhibited the highest DPPH activity in the first harvest.Overall,the results indicate that vermicompost dosage and harvest timing substantially influence the functional quality of L.graveolens.Moderate organic fertilization,particularly 5 t ha^(−1),enhances the biosynthesis of bioactive secondary metabolites,underscoring its potential for sustainable production systems.
基金financed by the Green Fund of the Hellenic Ministry of Environment and Energy,under the funding program“National Environment and Innovation Activities 2022”,Priority Axis“Research&Application”,Project“Sustainable technology for converting pomegranate residues into bioproducts and bioactive compounds”with the acronym“POMEGRANATE”.
文摘Pomegranate residues(PRs),namely pomegranate peels and seeds remaining after juice extraction,constitute a significant agro-industrial residue in Greece.Despite their ample content in carbon sources and bioactive compounds,PRs are largely unexploited,with their management being an increasing concern for the pome-granate processing industry.The objective of this study was the development and characterization of a bio-process aiming at the biotechnological valorization of PRs for ethanol production.Specifically,a stepwise investigation was conducted,including(i)the production and chemical characterization of extracts/hydrolysates from PRs using distinct pretreatments not involving organic solvents or enzymatic hydrolysis;(ii)the assessment of the exploitability of a selected hydrolysate as fermentation feedstock using Saccharomyces cerevisiae;and(iii)the advancement of the bioprocess through the joined utilization in the fermentation substrate of PRs and seeded raisins(SRs),another important agro-industrial residue in Greece.The finally developed substrate,comprising a mixture of PRs/SRs extracts at concentrations 60/40%v/v,was used in three fermentation trials,and the fermentation process was quantitatively described using the Aiba model.The developed bioprocess resulted in satisfactorily high bioethanol production with the maximum attained concentration being 50.0±0.6 g/L.The maximum specific growth rate(μ_(max))of S.cerevisiae was estimated to be 0.1351/h and the bioethanol yield(Y_(ps)),namely the amount of produced ethanol/amount of consumed reducing sugars,was estimated to be 0.423 g/g.Hence,PRs can be efficiently used in the development of a fermentation substrate for bioethanol production,providing an economic and environmentally sustainable alternative to conventional feedstocks.
基金the“Pioneer”and“Leading Goose”R&D Program of Zhejiang(No.2023C01072)the Institute of Zhejiang University-Quzhou for their financial support。
文摘Poly(phenylene oxide)(PPO)exhibits excellent dielectric properties,making it an ideal substrate for high-frequency,high-speed copper-clad laminates.The phenolic hydroxyl group at the end of PPO plays a key role in its reactivity.Accurately quantifying the phenolic hydroxyl content in PPO is essential but challenging.In this study,we proposed a method for measuring the phenolic hydroxyl content of PPO using differential UV absorption spectroscopy.In alkaline solutions,the phenolic hydroxyl in PPO completely ionizes to form phenoxide ions,leading to a significant increase in UV absorbance at approximately 250 and 300 nm.Notably,the differential UV absorbance at approximately 300 nm was directly proportional to the phenolic hydroxyl concentration.Using 2,6-dimethylphenol as a standard,a calibration curve was established to relate the phenolic hydroxyl concentration to differential UV absorbance at approximately 300 nm,providing a precise and straightforward method for phenolic hydroxyl quantification in PPO with distinct advantages over conventional techniques.
文摘By means of gel permeation chromatography analysis, the molecular weight of liquefied wood under different reaction conditions was investigated to trace the change in the structural characteristics of the liquefied wood. The insoluble residues were analyzed by Fourier transform infrared to investigate the liquefaction order of three main wood components. The results indicate that both reaction temperature and reaction time could affect the molecular characteristics of the liquefied wood obtained. The mo...
