Presence Of Resorcinol Research Articles

Determination of Glycerin from a Marketed Personal Care Product Using Gas Chromatography

The current study presents a packed column gas chromatographic technique for the estimation of glycerin using a flame ionization detector from a marketed hair tonic in presence of resorcinol, ethanol, biotin, keratin hydrolysate, undecylenic acid alkylolamide (hyalkyl HBU), D-biotin, nicotinic acid, and polyvinylpyrrolidone. The validation studies show the proposed method to be specific, sensitive, precise, and accurate. The method is found to be linear in the concentration range 1.25 mg/mL to 10.02 mg/mL with r2 value 0.99. The limit of detection and the limit of quantitation were 0.01 mg/mL and 0.05 mg/mL, respectively. The method does not involve any complex sample preparation procedure and is therefore suitable for regular analysis of glycerin from marketed hair tonic.

Fabrication of 3-Dimensional Porous Graphene Materials for Lithium Ion Batteries

A 3-dimensional porous graphene material (PGM) has been synthesized using a simple two-step process: hydrothermal reaction and calcination. Hydrothermal reaction of graphene oxide (GO) in the presence of resorcinol and glutaraldehyde leads to covalent grafting of partially reduced GO with glutaraldehyde and the deposition of phenolic resin. Subsequent calcination of the composite consisting of phenolic resin deposited on partially reduced GO in the presence of KOH produces structurally stable, highly porous graphene material with a specific surface area of ∼1,066±2m2g−1. When used as an active electrode material in a lithium battery, the PGM exhibits an initial discharge capacity of ∼1,538 mAh g−1, which is significantly higher than those of graphite and other carbonaceous materials reported previously. More importantly, when cycled at higher discharge/charge rates, the PGM-based electrodes still deliver large capacities and excellent cycling performance, demonstrating great potential for high-performance lithium-ion batteries. The attractive electrochemical performance of the PGM is attributed to its unique porous structure with large specific surface area and the presence of more disordered carbon atoms produced by the KOH activation.

Investigation and chromatographic separation of some phenolic compounds from flowers of Mentha longifolia l. and Mentha spicata l. growing in Iraq

Five of active phenolic compounds: Hydroquinone, Resorcinol, Coumarin, Vanillin and Gallic acid were separated and investigated by high performance liquid chromatography (HPLC) technique from the crude of ethanolic extract of Mentha longifolia L. and Mentha spicata L. and the retention time adopted as a base to investigation of those compounds. The results showed that the crude extracts of the species under study contains of Hydroquinone also Gallic acid compounds while those extracts differed in their content of other studied phenolic compounds, however the crude extract of M. longifolia distinguished by presence of Resorcinol and Vanillin, while Coumarin was limit in M. spicata crude extract only.

Solar photo-Fenton for water disinfection: An investigation of the competitive role of model organic matter for oxidative species

The competitive effect for the oxidative species produced during solar photo-Fenton process at neutral pH between an organic compound (resorcinol) and a model microorganism (Enterococcus faecalis) was investigated. With this purpose, the inactivation of E. faecalis was evaluated under several solar processes, i.e. SODIS, solar-UVA with H2O2 (10, 20 and 50mgL−1) and solar-UVA-Fe2+ (2.5, 5 and 20mgL−1) in the absence and presence of resorcinol (10mgL−1). The effect of resorcinol on the Fenton reaction (H2O2/Fe2+ in the dark: 5/2.5 and 50/20mgL−1) efficacy at neutral pH was also evaluated. In spite of resorcinol maintained a high amount of iron (around 10mgL−1) in solution during the experiments, with the highest concentrations of H2O2/Fe2+ (50/20mgL−1), only a 2-log decrease of bacteria was observed with 10mgL−1 of resorcinol, while a 3.5-log abatement was detected without resorcinol. These results highlight the competitive role of organic matter for the oxidant species against bacteria when photo-oxidation and photo-disinfection processes are occurring at the same time. This competition for the oxidant species, mainly hydroxyl radicals generated during photo-Fenton, was confirmed by (i) the solar photo-Fenton assays at three different concentrations (H2O2/Fe2+): 5/2.5, 10/5 and 20/10mgL−1, although at elevated concentrations of H2O2 and Fe2+ (50/20mgL−1) the disinfection efficiency was independent of the addition of resorcinol because an excess of radicals were generated, and (ii) by the photo-Fenton results obtained when the concentration of resorcinol was increased from 20, 30 till 40mgL−1.

Direct Synthesis of Ag Nanoparticles Incorporated on a Mesoporous Hybrid Material as a Sensitive Sensor for the Simultaneous Determination of Dihydroxybenzenes Isomers

AbstractThis paper describes the synthesis, characterization, and applications of a mesoporous silica/ multiwalled carbon nanotube (SiO2/MWCNT) hybrid material, which was obtained by a sol–gel process and decorated with silver nanoparticles (AgNPs) ranging in size from 5 to 8 nm. The AgNPs were prepared directly on the surface of the SiO2/MWCNTs material by using N,N‐dimethylformamide (DMF) as the reducing agent, and the resulting material was designated Ag/SiO2/MWCNT. The Ag/SiO2/MWCNT material was characterized by scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDS), high‐resolution transmission electron microscopy (HR‐TEM), and X‐ray photoelectron spectroscopy (XPS). A glassy carbon electrode, modified with the Ag/SiO2/MWCNT material, was used in the development of a sensitive electrochemical sensor for the determination of hydroquinone and catechol in the presence of resorcinol by squarewave voltammetry. Well‐defined and separate oxidation peaks were observed in phosphate buffer solution (PBS) at pH 7. The Ag/SiO2/MWCNT‐modified electrode exhibited high sensitivity for the simultaneous determination of hydroquinone and catechol in the presence of resorcinol, and the limits of detection for hydroquinone and catechol are 0.0117 and 0.0121 μM, respectively. No significant interference was seen for 2,6‐dichloroindophenol, phenol, 4‐nitrophenol, and nitrite ions in the detection of dihydroxybenzenes. Our study demonstrates that the resultant Ag/SiO2/MWCNT‐modified electrode can be used for hydroquinone and catechol detection in the presence of resorcinol and other potentially interfering materials in river water samples.

Inactivation of Enterococcus faecalis in simulated wastewater treatment plant effluent by solar photo-Fenton at initial neutral pH

Enterococcus faecalis inactivation was carried out by solar photo-Fenton at initial neutral pH in compound parabolic collectors with 20mgL−1 of Fe2+ and 50mgL−1 of H2O2 in different matrices [saline solution (0.9% NaCl), saline solution with resorcinol and a simulated secondary effluent from a municipal wastewater treatment plant (SEWWTP)]. The effects of mechanical stress, acidic pH, solar light, solar light/H2O2 and Fenton reaction were determined. Sunlight led to a 2-log bacterial decrease while H2O2 (50mgL−1) with solar light decreased E. faecalis concentration from 106 to 102CFUmL−1 and 1-log for Fenton reaction after 100min of treatment. The chemical composition of water matrix was shown to have a marked influence on E. faecalis inactivation by solar photo-Fenton. The detection limit was reached within 55min in the saline solution. The presence of resorcinol (Dissolved Organic Carbon: 10mgL−1) reduced the treatment time by 10min; whilst a 15min reduction was observed in SEWWTP and the final pH returned to neutral. E. faecalis inactivation results were satisfactorily fitted to a modified version of the classical Chick–Watson model. The kinetic constants were 0.193±0.005min−1 for saline solution, 0.294±0.016min−1 for saline solution with resorcinol, and 0.330±0.019min−1 for SEWWTP.

Simultaneous electroanalytical determination of hydroquinone and catechol in the presence of resorcinol at an SiO2/C electrode spin-coated with a thin film of Nb2O5

This paper describes the development, characterization and application of an Nb(2)O(5) film formed on the surface of a carbon ceramic material, SiO(2)/C, obtained by a sol-gel method, using the spin-coating technique. The working electrode using this material will be designated as SiCNb. Hydroquinone and catechol can be oxidized at this electrode in the presence of resorcinol, allowing their simultaneous detection. The electrochemical properties of the resulting electrode were investigated using cyclic and differential pulse voltammetry techniques. Well-defined and separated oxidation peaks were observed by differential pulse voltammetry in Tris-HCl buffer solution at pH 7 containing 1 mol L(-1) KCl in the supporting electrolyte solution. The SiCNb electrode exhibited high sensitivity in the simultaneous determination of hydroquinone and catechol in the presence of resorcinol, with the limits of detection for hydroquinone and catechol being 1.6 μmol L(-1) and 0.8 μmol L(-1), respectively. Theoretical calculations were performed to determine the ionization energies of hydroquinone, catechol and resorcinol; the results were used to explain the simultaneous determination of species by differential pulse voltammetry. The presence of resorcinol did not produce any interference in the simultaneous detection of hydroquinone and catechol on the surface of the modified electrode.

Disposition Pattern of Sulphur Functional Groups in High Sulphur Ledo Coals of Assam

Studies for determination of sulphur functional groups present in Ledo coal of Assam State of North Eastern Region of India were carried out using Temperature Programmed Reduction (TPR) method. TPR studies were carried out in presence of Resorcinol and hydrogen gas to arrive at the final result. TPR studies on model sulphur compounds viz. L-Cysteine, synthetic rubber, Thiokol, having hydroxyl terminal groups, thioplast, pyrite with sand, and Garlic were carried out in order to assign various sulphur functional groups present in Ledo coal. Six numbers of hydrogen sulphide evolutions from Ledo coal were observed in the temperature range of 190 - 220 0 C, 260 - 290 0 C, 360 - 390 0 C, 460 - 490 0 C, 510 - 540 0 C and 590 - 620 0 C corresponding to mercaptan/ disulphide (0.30), Thiol (1.70), AromaticThioether (0.50), Thiophene (0.90), pyrite + part of complex thiophene (0.60), part of complex thiophene (0.30), The thioketonic sulphur in Ledo coal is estimated to be 1.59 using controlled nitric acid oxidation experiments.

Uniform hierarchical MoO2/carbon spheres with high cycling performance for lithium ion batteries

Uniform hierarchical MoO2/C spheres have been prepared through calcination of a MoO3/resin precursor generated via a simple hydrothermal method in the presence of resorcinol, formaldehyde and (NH4)6Mo7O24·4H2O. The carbon spheres formed in situ by the carbonization of resorcinol–formaldehyde resin in a N2 atmosphere reduce MoO3 into MoO2 nanoparticles. The MoO2/C spheres have been characterized by XRD, SEM, HR-TEM and TGA. Used as an anode material, these spheres exhibit not only good rate capability but also high cycling performance. These hierarchical MoO2/C spheres are a promising anode material for high performance lithium ion batteries.

Electrogeneration of disinfection byproducts at a boron-doped diamond anode with resorcinol as a model substance

Abstract Electrochemical disinfection in chloride electrolyte with a boron-doped diamond (BDD) electrode has unique advantages due to the high oxidizing ability of active chlorine and reactive oxygen species produced under certain conditions in the electrolysis. However, the electrogeneration of disinfection byproducts (DBPs) in the presence of organics in the system has rarely been reported. In this study, the discontinuous formation of DBPs (chloroform, chlorate and perchlorate) was investigated in model water containing chloride electrolyte (10 mM) with a BDD anode in the presence of resorcinol (0.5 mM) at a current density of 20 mA cm −2 . We found that the formation of chloroform and chlorate increased with the free available chlorine production at the beginning and reached peaks at 2 h (0.01 mM), 4 h (1.67 mM), respectively. When the free available chlorine started to decrease, chloroform was gradually mineralized and chlorate was oxidized to perchlorate due to the strong and non-selective oxidizing ability of the BDD. After electrolysis for 25 h, only perchlorate was left (3.84 mM). So inorganic DBPs should be carefully watched in the BDD system. The chloride concentration in the electrolyte affected the production of all three DBPs, due to its influence on the active chlorine production. Organic was not involved in the chlorate and perchlorate formation, and thus the resorcinol concentration had little impact on inorganic DBPs. DBPs formation at acidic pH was lower than that in the basic condition, mainly due to the different forms of resorcinol and chlorine existing at different pH values. Compared with other endocrine disruptors (dimethyl phthalate, diethyl phthalate and bisphenol-A), resorcinol with high active structure showed the greatest reactivity in DBPs production.

Flow injection analysis of resorcinol using inhibited Rhodamine B/Cerium(IV) chemiluminescence system

The fluorescent dye Rhodamine B (RhB), in combination with a strong oxidant Ce(IV), was used to investigate the properties of three important polyphenols, resorcinol, catechol, and hydroquinone. The reaction of RhB with Ce(IV) solution in acidic medium was found to elicit strong chemiluminescence (CL). The CL signal remarkably weakened in the presence of resorcinol whereas the two other isomers, catechol, and hydroquinone, hardly had any effect in the same range of concentrations. Based on these observations, a new flow-injection CL method was developed for the determination of resorcinol. In addition, a brief discussion of possible mutual interaction mechanism between the three polyphenols and the components of the system is also presented.

Synthesis of wood‐based epoxy resins and their mechanical and adhesive properties

AbstractWood‐based epoxy resins were synthesized from resorcinol‐liquefied wood. Wood was first liquefied in the presence of resorcinol with or without a sulfuric acid catalyst at high temperature. Because of the hydroxyl groups, the resorcinol‐liquefied wood was considered as a precursor for synthesizing wood‐based epoxy resin. Namely, the phenolic OH groups of the liquefied wood reacted with epichlorohydrin under alkali condition. By the glycidyl etherification, epoxy functionality was introduced to the liquefied wood. The epoxy functionality of the resins was controlled by the concentration of phenolic OH groups in the liquefied wood, which would be a dominant factor for crosslink density and properties of the cured epoxy resins. The flexural strength (150–180 MPa) and the modulus of elasticity (3.2 GPa) of the highly crosslinked wood‐based epoxy resin were equivalent to those of the commercially available epoxy resin, diglycidyl ether of bisphenol A (DGEBA). Also, the shear adhesive strength of the wood‐based epoxy resin was higher than that of DGEBA when plywood was used as the adhesive substrates. The mechanical and adhesive properties suggested that the wood‐based epoxy resins would be well suited for matrix resins of natural plant‐fiber reinforced composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2285–2292, 2006

The synergistic effect of dicyandiamide and resorcinol in the curing of epoxy resins

AbstractThe synergistic effect of dicyandiamide (Dicy) and phenolic substances was studied, with resorcinol as a model compound. It was found that when Dicy and resorcinol are used jointly, the curing temperature of epoxy resin can be significantly lowered. FTIR and DSC data were used to illustrate the mechanism of the synergism. The addition of the phenolic hydroxyl group to epoxide was facilitated by Dicy, which favors the formation of phenoxy anions. The reaction of Dicy with epoxide was facilitated by resorcinol, which can exert “electrophilic assistance” for the addition of the amino group to epoxide. The presence of resorcinol also favors the addition of the hydroxyl group to the cyano group. The thermal and mechanical properties of the epoxy resins cured with Dicy/resorcinol or Dicy/phloroglucinol were studied. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1869–1874, 2003

SYNTHESIS AND CHELATION PROPERTIES OF SOME NEW MANNICH CONDENSATION POLYMERS CONTAINING A SALICYLALDOXIME GROUP

ABSTRACT A new oxime containing polymer, Poly(salicylaldoxime-3,5-diyl (N,N′-dimethylethylenediamine N,N′-bismethylene)), polymer 1, was prepared through a Mannich-type condensation of salicylaldoxime with formaldehyde and N,N′-dimethylethylenediamine. Polymer 2, a crosslinked chelating ion exchange resin, was obtained by a similar Mannich condensation in presence of resorcinol as the crosslinker. The sorption properties of these polymers towards the divalent ions, Mg2+, Ca2+, Ni2+, Zn2+, Cd2+, and Cu2+ were studied by a batch equilibration technique as a function of contact time and pH. Crosslinking is found to have profound effects on the surface morphology and the chelation properties of these polymers. The crosslinked Polymer 2 exhibited improved chelation characteristics in comparison with Polymer 1 and displayed faster rates of metal ion uptake and relatively higher capacities and selectivities. These findings are in keeping with the observed increase in hydrophilic character upon crosslinking.

The kinetic behavior for the electrochemical polymerization of aniline in aqueous solution

The electrochemical oxidation of aniline in 0.8 M HCl solution is carried out using repeated potential cycling between 0 and 1.1 V (versus SCE). Its anodic peak current at 1.0 V for the first scan is markedly retarded in the presence of resorcinol or phloroglucinol, and decreases with increasing their concentrations. However, this peak current is slightly affected by hydroquinone, because it is oxidized electrochemically before oxidation of aniline. The experiment of the rotating ring-disk electrode shows that both the disk current at 1.0 V and the ring current for electrolysis of aniline are simultaneously decreased in the presence of resorcinol. This means that a soluble intermediate cation generated at the disk electrode is captured by resorcinol. There are four anodic peaks and three reduction peaks on the cyclic voltammograms during oxidation of aniline by repeated potential cycling. From the temperature dependence of the separate anodic peak currents, the activation energy of each reaction is calculated. For the first scan, the oxidation of aniline at 1.0 V involves two different activation energies at temperatures from 1 to 35 °C. Both activation energies are smaller than 21 kJ mol −1. The values fall into the range of activation energies for a general propagation reaction and termination reaction of free radical polymerization. These experimental facts indicate that the initial stage of aniline oxidation is the most likely to involve the formation of a radical cation.

Substituted catechols as complexing agents for the determination of bismuth, lead, copper and cadmium by adsorptive stripping voltammetry

Copper, cadmium, lead and bismuth (> 5 μg ml −1) are determined by adsorptive cathodic stripping voltammetry (AdCSV) on a mercury film glassy carbon electrode, using catechol, 4-methylcatechol, 4- t-butylcatechol and resorcinol as complexing ligands. Complexes of lead, copper and bismuth with resorcinol showed the largest increase in current with increase in metal concentration, whereas complexes of these metals with 4- t-butylcatechol showed the lowest current response. Cadmium showed a different behaviour from the other three metals in that the highest current response was observed with 4-methylcatechol. The four metals could be determined simultaneously in the presence of resorcinol, although considerable interference was observed between bismuth and copper.

Dechlorination of PCDD/F by organic and inorganic electron transfer molecules in reduced environments

The dechlorination of octa- and pentachlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) was investigated using organic and inorganic electron shuttles relevant to anaerobic sediments. OctaCDD was dechlorinated to hexaCDD in the presence of resorcinol, catechol, and 3,4-dichlorobenzoate, resulting in an increase of 2,3,7,8-substituted hepta- and hexaCDD. Vitamin B 12 mediated the dechlorination of octaCDD to tetraCDD, octaCDF to hexaCDF, and 1,2,3,7,8-pentaCDD to at least two tetraCDD, including 2,3,7,8-TCDD. Zerovalent zinc stoichiometrically dechlorinated octaCDD to hexa- and pentaCDD under basic and neutral conditions, respectively. Thus, abiotically-mediated dechlorination reactions may contribute significantly to the fate of PCDD/F in reduced environments.

Phototransformation of resorcinol induced by excitation of nitrite and nitrate ions. I: Nitrite ions

The excitation of nitrite ions in the presence of resorcinol (I) leads to the formation of 4‐nitrosoresorcinol (II) as the major photoproduct. The reaction is inhibited by formate ions, but this inhibition is much more efficient in degassed solution than in air‐saturated medium. In the absence of formate ions, the transformation is not affected by the presence of oxygen. From the influence of oxygen and formate ions, it is concluded that the formation of II results from a reaction of I with N2O3. Dinitrogen trioxide is formed by oxidation of nitrite ions by hydroxyl radicals resulting from the photolysis of nitrite ions:

Synthesis of Potential Metabolites of Ethyl (E)-4-[2-(3,4-Dihydro-4,4-dimethyl-2H-1-benzopyran-6-yl)-1-propenyl]benzoate

Potential metabolites of ethyl (E)-4-[2-(3,4-dihydro-4,4-dimethyl-2H-1-benzopyran-6-yl)-1-propenyl]benzoate were synthesized. The new compounds include ethyl 3-[3,4-dihydro-4,4-dimethyl-2H-1 -benzopyran-6-yl]crotonate, 3-[3,4-dihydro-4,4-dimethyl-2H-1 -benzopyran-6-yl]crotonic acid, 3,4-dihydro-4,4-dimethyl-2H-1-benzopyran-6-carboxylic acid, 4-[3,4-dihydro-4,4-dimethyl-2H-1-benzopyran-6-yl]Δ2-butenolide, ethyl (E)-4-[3,4-dihydro-4,4-dimethyl-2/+1 -benzopyran-6-yl)-3-hydroxy-1-propenyljbenzoate, ethyl (E)-4-[2-(3,4-dihydro-4,4-dimethyl-2H-1-benzopyran-6-yl)-2-propenal] benzoate, and ethyl (E)-4-[2-(3,4-dihydro-4,4-dimethyl-2H-1-benzopyran-6-yl)-2-propenoic acid]benzoate. Stereospecific oxidizing reagents and/or conditions were developed for these sensitive systems and include the use of SeO2, Clorox bleach, activated MnO2, and NaClO2 in the presence of resorcinol as a chlorine scavenger.

Characterization of the Rhodococcus sp. BPG‐8 resorcinol hydroxylase

AbstractA thermo‐unstable hydroxylase was isolated from a Rhodococcus sp. BPG‐8. Activity for the partially purified hydroxylase was enhanced and stabilized in the presence of FAD and catalase. The Vmax values for the oxidation of NADH was 0.28 μmoles · min−1 · mg−1 protein and Km value was 8.3 μM in the presence of these compounds, while in their absence the Vmax value was reduced to 0.09 μmoles · min−1 · mg−1 protein while the Km value changed to 16.1 μM. Resorcinol hydroxylase activity was optimal at pH 7.0, and 25° C. The optimal substrate concentrations were 68 μM and 125 μM in the presence and absence of FAD/catalase, respectively. Chloride ion, and metal ions inhibited the resorcinol hydroxylase activity. The resorcinol hydroxylase utilized various other substrates, and did not influence the hydroxylase activity in the presence of resorcinol.