New 5-Alkenyl Resorcinols from <i>Lithraea molleoides</i>(Vell). Eng.

Lithraea molleoides (Anacardiaceae) is a tree that grows in South America including Southern Brazil, Southern, and Eastern Bolivia, Southern Paraguay, Northern, and Central Argentina. Infusions, decoctions, or tinctures from its aerial parts (leaves, buds, and young stems) are employed in ethnomedicine mainly against respiratory, and digestive inflammations and illnesses. Antibacterial, antiviral, antioxidant, anti-inflammatory, and antinociceptive activities, among others, have been reported for L. molleoides. Many of its biological activities have been associated with the reported presence of 5-alkenyl resorcinols. Alkyl/alkenyl catechols and alkyl/alkenyl resorcinols are very common in members of the Anacardiaceae family and several activities have been attributed to them. This work describes the isolation and the structural elucidation of three new 5-alkenyl resorcinols isolated from Lithraea molleoides reported in nature for the first time.

Preparation and characterization of a nanostructured lipid carrier for phenylethyl resorcinol

Phenylethyl resorcinol(PR)demonstrates inhibitory effects on multiple targets in the melanin synthesis pathway,resulting in a strong whitening effect.However,challenges such as limited solubility in water and susceptibility to oxidation and discoloration restrict its practical application in the cosmetics industry.In order to enhance stability and performance characteristics,a whitening nanostructured lipid carrier(NLC)was synthesized through high-pressure homogenization.This method entailed the incorporation of solid lipids,a liquid lipid,and a compound emulsifier,with deionized water fulfilling the roles of solid phase,liquid phase,and water phase,respectively.The NLC's particle size,Zeta potential,stability,encapsulation efficiency,and other parameters were assessed using techniques such as particle sizer,stability analyzer,and HPLC.The results showed that the NLC for phenylethyl resorcinol prepared by using the optimal formula(7.50%solid lipids,3.00%ethylhexyl palmitate,and 2.00%Tween 80 and soybean lecithin)has an encapsulation efficiency of 87.11%,a particle size of 157.2±0.70 nm,a kinetic instability of less than 1.2,and a greatly improved stability,thereby successfully solving the problems of unstable storage and poor solubility of phenylethyl resorcinol.

Vesicular carriers containing phenylethyl resorcinol for topical delivery system; liposomes, transfersomes and invasomes

Topical administration of phenylethyl resorcinol(PR) has attracted much attention as skin lightening agent with potent anti-tyrosinase activity. Two novel types of elastic carriers were developed to overcome the limitation of PR as topical delivery by increasing the solubility, stability and decreasing skin irritation compared to conventional liposomes. In addition, it also promotes skin penetration of PR to reach deep skin layer at the target site. The lead formulations were obtained from the invasomes containing 1%(w/v) d-limonene mixed with 10%(v/v) absolute ethanol as the skin enhancer, and transfersomes containing 15%(w/w) sodium deoxycholate(SDC) as edge activator. All formulations gave a vesicle size < 500 nm, polydispersity index(PDI) < 0.3, high zeta potential, entrapment efficiency > 50%, and good stability on storage at 30 °C at 75% RH for 4 months. Transfersomes have a lower degree of deformability(6.63%) than invasomes(25.26%). In contrast, the liposomes as rigid vesicles do not show a deformable property. This characteristic affects the skin permeation, and thus, transfersomes with high elastic property provided a significantly higher cumulative amount, steady state flux( J ss) and permeability coefficient( K p) compared to other formulations. However, in vitro PR accumulation in full-thickness newborn pig skin demonstrated that the application of elastic carrier formulations gave significantly higher accumulation than liposomes, and gave anti-tyrosinase activity up to 80%. These results are straightforwardly related to the results of cellular level study. Transfersomes and invasomes showed higher tyrosinase inhibition activity and melanin content reduction when compared to liposomes in B16 melanoma cells. In addition, acute irritation test in rabbits confirmed that these formulations are safe for skin application. Therefore, elastic vesicle carriers have theefficiency to deliver PR into the deep skin in both quantity and effectiveness which are better than conventional liposomes and appropriate for a skin lightening product.

Resorcinol-formaldehyde resin-based porous carbon spheres with high CO_2 capture capacities

Porous carbon spheres are prepared by direct carbonization of potassium salt of resorcinol-formaldehyde resin spheres, and are investigated as COadsorbents. It is found that the prepared carbon materials still maintain the typical spherical shapes after the activation, and have highly developed ultra-microporosity with uniform pore size, indicating that almost the activation takes place in the interior of the polymer spheres. The narrow-distributed ultra-micropores are attributed to the "in-situ homogeneous activation"effect produced by the mono-dispersed potassium ions as a form of -OK groups in the bulk of polymer spheres. The CS-1 sample prepared under a KOH/resins weight ratio of 1 shows a very high COcapture capacity of 4.83 mmol/g and good CO/Nselectivity of7-45. We believe that the presence of a welldeveloped ultra-microporosity is responsible for excellent COsorption performance at room temperature and ambient pressure.

Measurement and correlation of phase equilibrium data of the mixtures consisting of water, resorcinol, mesityl oxide at different temperatures

Liquid–liquid equilibrium(LLE) data were measured for the ternary system of water + resorcinol + mesityl oxide under atmospheric pressure at temperatures of(298.2, 323.2, 333.2, 343.2 and 353.2) K. The reliability of the experimental data was verified by the Hand and Bachman equations. The distribution coefficient and selectivity were calculated from the experimental LLE data, which showed high efficiency of mesityl oxide extracting resorcinol from the aqueous solution. The NRTL and UNIQUAC models were employed to fit the measured experimental LLE data and yield corresponding binary interaction parameters.

Mechanistic insights into the selective hydrogenation of resorcinol to 1,3-cyclohexanedione over Pd/rGO catalyst through DFT calculation

In our previous work, graphene-supported Pd catalyst(Pd/rGO) exhibited higher activity and selectivity for the liquid phase selective hydrogenation of resorcinol to 1,3-cyclohexanedione compared with other catalysts. In the present study, further experimental and theoretical investigations were conducted to reveal the reaction mechanism and the catalytic mechanism of Pd/rGO for resorcinol hydrogenation. The effects of graphene nanosheet and the solvent on the reaction were investigated, and the pathway for resorcinol hydrogenation was proposed supported by density functional theory(DFT) calculations. The results showed that the excellent selectivity of Pd/rGO to 1,3-cyclohexanedione was attributed to the strong π–π and p–π interactions between the graphene nanosheet and the benzene ring as well as hydroxyl in resorcinol molecule, which was in agreement with our previous speculation. In weak polar aprotic solvents, solvation free energy had less impact to the π–π and p–π interactions mentioned above. In strong polar aprotic solvents and polar protic solvents,however, the influence of solvation free energy was much greater, which led to the decrease in the conversion of resorcinol and the selectivity to 1,3-cyclohexanedione.

Induction of apoptosis on human hepatocarcinoma cell lines by an alkyl resorcinol isolated from Lithraea molleoides

AIM: To study the mechanism of cytotoxicity of a new active 5-alkyl resorcinol [1, 3-dihydroxy-5- (tridec-4’, 7’ -dienyl) benzene] isolated from Lithraea molleoides leaves on liver tumor cells. METHODS: Human hepatocarcinoma cell lines (HepG2 and Hep3B) in culture were treated with inhibitory concentrations, 50% of the compound, for 24 h. The induction of apoptosis was detected in treated cells by analysis of DNA fragmentation, DNA content, and acridine orange and propidium iodide staining. RESULTS: After 24 h of 5-alkyl resorcinol treatment, both cell lines showed: (1) the typical morphological alterations of apoptosis; (2) DNA fragmentation, detected by laddering and appearance of a subG0 population by flow cytometry; and (3) condensed and fragmented nuclei by acridine orange-propidium iodide staining. CONCLUSION: Based on the results, this compound exerts its cytotoxic effect in both hepatocellular cell lines through apoptotic cell death. For Hep3B, cells with mutated p53 and Fas, apoptosis would proceed by p53- or Fas-independent pathways.

NaOH and Ba(OH)_2 Compound Catalyzed PhenolResorcinol-Formaldehyde Copolycondensation Resin Adhesive for Recombined Bamboo

In order to reduce the curing temperature, shorten the curing time of phenol-formaldehyde(PF) resin adhesive, and ensure the good water-solubility, NaOH and Ba(OH)_2 were used as compound catalysts. The influences of the adding time of Ba(OH)_2, the adding amount of NaOH, Ba(OH)_2 and resorcinol on the properties of adhesives were studied. The properties of NaOH catalyzed phenol-formaldehyde(PF) adhesive, NaOH and Ba(OH)_2 compound catalyzed PF adhesive, NaOH and Ba(OH)_2 compound catalyzed phenol-resorcinol-formaldehyde(PRF) adhesive, and the prepared recombinant bamboo with three kinds of adhesives were compared. The experimental results show that NaOH and Ba(OH)_2 compound catalyst not only shortens the curing time of PF adhesive, but also guarantees the suitable water solubility of adhesive. After copolycondensation with resorcinol, the curing time of adhesive is further shortened, the water solubility is improved obviously, and the highest bonding strength is obtained. Infrared spectrum analysis shows that the reaction activity point of NaOH and Ba(OH)_2 compound catalyzed PRF adhesive will increase, so that both the curing temperature and curing enthalpy decrease.

A NOVEL EOR POLYMER (Ⅰ)—STUDY ON GELATION OF RESORCINOL-FORMALDEHYDE SYSTEMS

Factors affecting the gelation of resorcinol-formaldehyde systems have been examined overvariable ranges applicable to oilfield use. Gelation of resorcinol-formaldehyde (RF) system wassensitive to pH,salinity and hardness. Generally,this gel system could be used in fresh water orlow salinity brine at pH higher than about 9. The application would require careful monitoring ofinjection fluids to avoid premature gelation or prolonged shut-in times,especially under conditionsof low salinity and high pH. Salinity and hardness compatibilities of the system were improved bysulfomethylation of resorcinol. Aqueous sulfomethylated resorcinol formaldehyde (SMRF)system could be used in brine with higher salinity and hardness and at a wider pH range of 5--10.

Simultaneous deternubation of the contents of phenol and resorcinol in compound resorcinol paint by linear combination method of absorbances

Linear combination method of absorbances was used for the simultaneous determinationof phenol and resorcinol whose absorption spectra overlap severely in the compound resorcinolpaint.The determination wavelengths were 265.0nm,270.0nm,273.4nm and 278.0nm.The averagerecoveries for phenol and resorcinol were 100.28±0.30% and 99.52±0.22%,respectively.

Study on CeO_2/CuFe_2O_4 Catalytic Ozonation of Resorcinol

In order to improve the catalytic ozonation effect of resorcinol, the spinel CuFe_2O_4 was modified by doped CeO_2, and X-ray diffraction(XRD) and scanning electron microscopy(SEM) were used for characterization analysis. The effects of composite catalyst CeO_2/CuFe_2O_4 dosage, ozone dosage, initial pH and reaction temperature on degradation were studied, and the stability of the catalyst was tested. The results showed that the composite effect of CeO_2/CuFe_2O_4 prepared by combustion method was good, and the catalyst presented a laminated structure, in which 30 wt% CeO_2/CuFe_2O_4 degradation effect was significant. The removal rate of resorcinol using CeO_2/CuFe_2O_4 composite catalyst was higher than that using ozone or CuFe_2O_4 separately by 41.8% and 11.9%, respectively. In a reaction with resorcinol concentration of 100 mg/L, the catalyst dosage of 1.0 g/L, the ozone dosage of 2.5 mg/(L·min), at pH=9, temperature of 20 ℃, for reaction time of 40 min, the resorcinol removal rate was 88.5%. The catalyst CeO_2/CuFe_2O_4 still showed good degradation effect after repeatedly using for 10 times, and the dissolution rate of metal ions was lower than that of CuFe_2O_4.

Surface grafting of resorcinol onto polyethylene film

Low density polyethylene film surface-grafted resorcinol was prepared by a sequential process.Firstly, acrylic acid was grafted to the surface of low density polyethylene by UV photo-grafting.Secondly, the carboxylic groups in poly（acrylic acid） chains were transferred to acyl chloride groups by the reaction of carboxylic groups with thionyl chloride.The stability of acyl chloride groups in several solvents（alcohol, water, acetone, aqueous NaOH and in N2 atmosphere） was investigated, and N2 atmosphere and acetone were appropriate media to protect acyl chloride groups from side reaction.Finally, resorcinol monomer reacted with acyl chloride to append to the poly（acrylic acid）chains at room temperature.FT-IR-ATR was used to characterize the change of carbonyl groups during each step of the grafting process.Furthermore, by the experimental data of gravimetric analysis the grafted resorcinol monomer on the surface of low density polyethylene film was verified to have undergone condensation with acetone further in the resorcinol/acetone solution at 56℃, which might be a useful feature for synthesizing a thermoplastic/thermosetting composition.

Adsorptive removal of resorcinol on a novel ordered mesoporous carbon(OMC) employing COK-19 silica scaffold:Kinetics and equilibrium study

Phenolic compounds and their derivatives have been found in industrial wastewater, which pose threats to the natural environment. Ordered mesoporous carbon(OMC) has been identified as an ideal adsorbent possessing high specific surface area and large pore volume to alleviate these pollutants. A novel ordered mesoporous carbon was prepared using COK-19 template with the cubic Fm3 m structure for the first time. Ordered mesoporous silica COK-19 was synthesized and reported in 2015. Sucrose as the carbon precursor was impregnated into the mesopores of silica and converted to carbon through carbonization process using sulfuric acid as a catalyst. Ordered mesoporous carbon was obtained after the removal of silica framework using hydrofluoric acid. Boric acid was employed for the preparation of OMCs with tunable pore sizes in the range of 6.9–16.6 nm. Several characterization techniques such as nitrogen adsorption–desorption isotherms, transmission electron microscope(TEM), Fourier transform infrared spectroscopy, Boehm titration and elemental analysis were employed to characterize the OMCs. The pore size analysis and TEM images confirmed that OMC has replicated the mesostructure of the COK-19. Results obtained from adsorption kinetics and isotherms suggest that the Pseudo-second-order model and Langmuir isotherm well described the experimental data.

Stereoselective Synthesis of (Z)-5-(Trideca-4-enyl)resorcinol and Gibbilimbols A—D

Z)-5-(Trideca-4-enyl)resorcinol (1) and gibbilimbols AD (25) were synthesized in 47%60% yields over 6 steps from commercially available starting materials. The Wittig reaction of various alkyl phosphonium bromides with appropriate aldehydes in the presence of potassium tert-butoxide (t-BuOK) in anhydrous THF solution at room temperature served as the key step, and the result showed that only (Z)-configuration olefins were formed by this procedure. The synthesis of the (Z)-5-(trideca-4-enyl)resorcinol (1) was reported for the first time.

Synthesis and Structure Investigation of a Novel 3-Dimensional Potassium Supermolecular Compound Based on 2,4-Dinitro Resorcinol

A novel 3-dimensional potassium supermolecular compound [K（HDNR）（H2DNR）（H20）], （H2DNR 2,4-dinitro resorcinol） was synthesized and characterized by elemental analysis and FT-IR spectroscopy. The crystal structure investigated by X-ray single crystal diffraction shows that [K（HDNR）（HzDNR）（H20）],, crystallizes with a monoclinic unit cell in the space group P2（1）/c with unit cell dimensions of a= 17.648（5） A, b= 12.527（3） A, c= 7.735（2） A, β=94.33（2）°, V= 1705.00（73） A3, Z=4. The structure was refined to the final R=0.0670 and wR= 0.0722 for 2022 observed reflections with 1〉2σ（/）. In the compound, potassium cation is assembled into one-dimensional chains along c-axis through oxygen atoms from water molecules, and the chains were connected by the bridged HDNR- anions to form a two-dimensional net structure. The two-dimensional nets constructed a three-dimensional supramolecular architecture via intermolecular hydrogen bonds and N--O…π interaction. Density functional theory （DFT） B3LYP was employed to optimize the structure and calculate energies for three tautomers of HDNR univalent anion. Three stable tautomers were located. It was found that the structure （I） with O（1） losing hydrogen atom is more stable than the structure （II） also with O（1） losing hydrogen atom and the structure （III） with O（4） losing hydrogen atom.

Fabrication of disk-shaped,deuterated resorcinol/formaldehyde foam target for laser-plasma experiments

Resorcinol/formaldehyde(RF)foam resin is an attractive material as a low-density target in high-power laser–plasma experiments because of its fine network structure,transparency in the visible region,and low-Z element(hydrogen,carbon,and oxygen)composition.In this study,we developed disk-shaped RF foam and deuterated RF foam targets with 40–200μm thickness and approximately 100 mg/cm^(3) density having a network structure from 100 nm to a few micrometers cell size.By deuteration,the polymerization rate was drastically slowed down owing to kinetic isotope effects.These targets were used in high-power laser experiments where a megaelectronvolt proton beam was successfully generated.

SPECTROPHOTOMETRIC STUDY ON THE REACTION BETWEEN IRON (Ⅱ) AND 4-(2-THIAZOLYLAZO)-RESORCINOL

Ⅰ. INTRODUCTION 4-(2-Thiazolylazo)-resorcinol (TAR)can form colored complexes with many metal ions and has been widely used as a color producing reagent for spectrophotometry. Most of its complexes with metal ions have the maximum absorbance within the wavelengths of 500—550 nm and molar absorptivities of 2×10~4—6×10~4.

Biodegradation of resorcinol by Pseudomonas sp.

Objective:To investigate the ability of Pseudomonas sp.isolated from East Azarbaijan,Iran in bioremediation of resorcinol.Methods:Resorcinol biodegradation was evaluated using spectrophotometry and confirmed by gas chromatography-mass spectroscopy.Results:This isolate was able to remove up to 37.12%of resorcinol from contaminated water.Reusability experiments had confirmed the biodegradation process which produced seven intermediate compounds.These intermediates were characterized by gas chromatography-mass spectroscopy technique.The products of resorcinol biodegradation were apparently 1,4-cyclohexadiene,nonadecene,2-heptadecanone,1-isopropyl-2-methoxy-4-methylbenzene,hexadecanoic acid,9-octadecenoic acid,phenol and 5-methyl-2-(1-methylethyl).Conclusions:The findings revealed that Pseudomonas sp.is able to degrade resorcinol.Because of being an indigenous organism,this isolate is more compatible with the climate of the northwest region of Iran and possibly will be used for degradation of other similar aromatic compounds.

Synthesis of mesoporous tin dioxide via sol-gel process assisted by resorcinol-formaldehyde gel

Tin dioxide is a useful n-type oxide semiconductor used in a variety of applications owing to its superior optical, electrical, and multifunctional properties. Here, we used a network of resorcinol-formaldehyde （RF） gel to synthesize mesoporous tin dioxide via a sol-gel process. The effects of various synthesis parameters on the morphology and mesoporosity of the obtained product were investigated, including aging time of the RF gel, tin-to-formaldehyde molar ratio, resorcinol-to-carbonate molar ratio, and the aging time of the tin/RF mixed gel. Our experimental results showed that the interaction between the network of the RF gel and tin-containing sol is a key factor that affected the structural strength of the porous network and the porosity of the final product. Through control of the interactions in the tin/RF mixed gel we obtained porous tin dioxide materials that could be effectively used to form large-surface area films with desirable mesoporous properties.

Fabrication of Graphene/polydopamine Modified Electrode and Simultaneous Determination of Hydroquinone, Catechol and Resorcinol

Graphite oxide(GO) prepared by an improved Hummers method was reduced to graphene(Gr) by a hydrothermal method with Na BH4 as a reductant. Gr sample was characterized by scanning electron microscopy, X-ray diffraction and BET specific surface area analysis, respectively. The Gr-PDA modified glass carbon electrode(Gr-PDA/GCE) was designed and constructed for the simultaneous determination of hydroquinone(HQ), catechol(CC) and resorcinol(RC). The electrochemical behaviors of HQ, CC and RC on the Gr-PDA/GCE were investigated by cyclic voltammetry(CV) and differential pulse voltammetry(DPV) techniques. The results show that there are the three detections with a high peak current on the modified electrode duo to the synergetic effects of Gr and PDA, the linear response ranges for HQ and CC are 40.2–1559.6 and 24.7–1105.0 μM and the detection limits(S/N=3) are 13.4 and 8.2 μM, respectively.