bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Novel Spectrometer for Simultaneous Chemical Analyses
Authors: Huang Tzer‐Hsiang 
Published: June 2015

AbstractA novel spectrometer incorporating a multichannel detector for simultaneous multi‐element atomic emission spectrometry (AES) is described. The spectrometer consists of a multi‐bandpass optical filter comprised of a concave and a fiat grating in substractive mode, and a high resolution stage which utilizes an echelle grating and an one inch 1024‐channel photodiode array as the detector. Characterization with respect to the spectral resolution, the spectral response, and the capability of multi‐element detection demonstrated the systems's potential for simultaneous chemical analyses without moving any mechanical parts. To adjust the system for the analyses of different sets of elements, the corresponding mask is simply placed in position.
Kinetic Study of the Bromine‐Catalyzed Isomerization of Methyl‐ and Chloro‐Maleic Acids in Aqueous Ce(IV)‐Br ‐H2SO4 Medium
Authors: Jwo Jing‐Jer , Huang Che‐Yuan , Chang Eng‐Fen , Wu Ru Rong 
Published: June 2015

AbstractMethylmaleic (citraconic, CTA) acid and methylfumaric (measaconic, MSA) acid in aqueous sulfuric acid solution undergo bromine‐catalyzed reversible cis‐trans isomerization in the presence of ceric and bromide ions. The positional isomerization of CTA or MSA to itaconic acid (ITA) is not observed. The method of high performance liquid chromatography (HPLC) was applied to study the kinetics of this catalyzed isomerization. The major catalytic species is best expressed as the Br−2 · radical anion. Under suitable catalytic conditions, there is a tendency for the [MSA]/[CTA] ratio to reach an equilibrium value of 4.10 at 25° for the CTA+Br−2 · ⇄ MSA+Br−2 · reaction. Chloromaleic (CMA) and chlorofumaric (CFA) acids undergo similar isomerization with an equilibrium [CFA]/[CMA] ratio of 10.3 at 25°. The isomerization of maleic acid (MA) to fumaric acid (FA) is essentially irreversible with 50 as the lower limit of the equilibrium [FA]/[MA] ratio. The substituent has an important effect on the reversibility of this catalyzed isomerization of butenedicarboxylic acids. The thermodynamic parameters ΔH° and ΔS° at 25° for the CTA+Br−2 · ⇄ MSA+Br−2 · reaction were found to be −5.1±0.7 kj/mol and −6.0±3.3 J/mol K, respectively. The present method gives a plausible way to measure the differences in enthalpy and entropy between the trans‐ and cis‐isomers of butenedicarboxylic acids (CRCO2H=CR'CO2H) in aqueous solution.
Organotransition‐Metal Complexes of Multidentates 2. Synthesis and Allyl Bromination of N, N‐Bis(3,5‐Dimethylpyrazol‐1‐YL)Methane Derivatives of the Group VI Metal Carbonyls
Authors: Shiu Kom‐Bei , Chang Cho‐Jin 
Published: June 2015

AbstractN,N‐Bis(3,5‐dimethylpyrazol‐1‐yl)methane (H2CPz'2) reacts with the hexacarbonyls of chromium, molybdenum, and tungsten to give cis‐(H2CPz'2)M(CO)4 derivatives with M=Cr, Mo, W. The direct allyl bromination of these complexes is also investigated and only the molybdenum complex is converted into (H2CPz'2)Mo(CO)2(π‐C3H3)(Br).
Syntheses and Electrical Conductivities of 9‐Fluorenone‐Iodine‐Alkali Iodide Complexes
Authors: Yang Hsin‐Sheng , Wang Chi‐Ming 
Published: June 2015

AbstractA new series of 9‐fluorenone‐iodine‐alkali iodide complexes (FIMI, M=Na, K, Rb or Cs) has been prepared from chloroform. These complexes yield needle‐like crystals with metallic luster along the needle axis. The longitudinal dc conductivities at room temperature are in the order of 10−3 to 10−5 S cm−1. They all have semiconductive properties with activation energies of about 0.4 to 0.7 eV. A significant result is that the conductivity varies systematically with the cation size. A decrease in the cation size results in an increase in the conductivity. Resonance Raman spectra show that iodine is present as a linear chain of symmetric I−3 units in these complexes. Infrared spectra of these complexes are discussed with an attempt to estimate the interaction between the alkali cation and the carbonyl group of 9‐fluorenone.
Cycloaddition of Trichloronitrosomethane to Conjugated Dienes
Authors: Lin Cheng‐Tung , Chen Jyun‐Hung 
Published: June 2015

AbstractAddition of trichloronitrosomethane to 1,3‐cycloalkadienes gives [2+4] cpclo‐adducts. However, reactions with acyclic 1,3‐butadienes afford unstable cycloadducts which hydrolyze in water‐ether solution to produce N‐chloroformyl‐3,6‐dihydro‐l, 2‐oxazines. The later compounds are reduced to N‐methyl or converted to N‐methoxylcarbonyl derivatives in high yields.
Determination of Polycyclic Aromatic Hydrocarbons in Airborne Particulate by High Performance Liquid Chromatography
Authors: Wang P. , Yen V. O. , Tsai H. T. , Cheng James C. 
Published: June 2015

AbstractThis paper presents a trisolvent ultrasonic extraction and HPLC analysis method for the determination of 11 polycyclic aromatic hydrocarbons in air particulate collected on an air filter by a commercial high volume air sampler. A reverse phase column, Vydac 201 TP, and a gradient mobile phase, acetonitrile/water, were used. The 11 PAHs, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a, h]anthracene, benzo[ghi]perylene, indeno[1,2,3‐cd]pyrene, and coronene were completely resolved under experimental conditions. All the PAHs except coronene were monitored by fluorescence with λex=270 nm, λem>389 nm. Coronene was monitored by UV with λ=300 nm. The methodology was evaluated by spiking SRM 1649 with a PAH standard and then going through different extraction procedures and analyzing the PAH concentrations without clean‐up. An external standard method was used for quantitation. The recovery yields for fluoranthene, benz[a]anthracene, benzo[a]pyrene, benzo[ghi]perylene and indeno[l,2,3‐cd]pyrene were above 90%. The detection limits of PAH with fluorescence at λex=270 nm, λem>389 nm ranged from 5.7 pg to 69.5 pg.
Synthesis and Biological Activity of Pyrazolo(3,4‐D)‐8‐Amino‐1‐Azaquinoxaline Dimethine Cyanine Dyes
Authors: El‐Maghraby M. A. , Khalafallah A. K. , Hassan M. E. , Soleiman H. A. 
Published: June 2015

AbstractNew asymmetrical dimethine cyanines (Va–f) and their bases (VIa,b), incorporating pyrazolo(3,4‐d)‐8‐amino‐1‐azaquinoxaline moiety or its ethiodide, have been prepared and tested for their antibacterial and fungicidal activities.
Synthesis of Novel 1,3,5‐Trisubstituted Pyrazoles as Potential Hypoglycemic Agents
Authors: Mokhtar Hassan M. , El‐Khawass S. M. 
Published: June 2015

AbstractA novel series of 1,3,5‐trisubstituted pyrazoles was synthesized. Thus, ethyl 2,4‐dioxo‐6‐phenylhex‐5‐enoate (I) was condensed with phenylhydrazine to afford 3‐ethoxycarbonyl‐1‐phenyl‐5‐styrylpyrazole (II) which on fusion with hydrazine hydrate gave the corresponding acid hydrazide (III). Reaction of III with the appropriate isothiocyanate yielded the disubstituted thiosemicarbazides (IVa‐e) which were cyclized into thiotriazoles (Va‐e), thiadiazoles (Vla‐e) and oxadiazoles (VIIa‐). The structure of the newly synthesized compounds was elucidated by elemental analyses, IR and 1H NMR spectra.
Computer Control of a Multichannel Scaler and Quadrupole Mass Filter with an IBM pc
Authors: Yeh T. S. , Su T.‐M. , Lin H. C. 
Published: June 2015

AbstractAn interface for a Canberra Model 7880 fast multiscaler and an Extranuclear quadrupole controller with an IBM PC is described. With the interface and using only a few keystrokes one can choose to take either a mass spectrum or a time‐of‐flight spectrum of a given mass. The limitations and the minor modifications of the original hardware are also discussed.
Determination of Trace Metal Species in the Suspended Matter of Riverine and Estuarine Waters
Authors: Hung Jia‐Jang 
Published: June 2015

AbstractA sequential extraction technique was used to determine the chemical species of six metals (Fe, Mn, Cu, Zn, Pb, Cd) in suspended matter of the Kaoping and Tsengwen river basins. The samples were taken to cover the fresh and marine characteristics. The precision of the species determination was estimated by the relative difference between the concentration of total metal and the sum concentation of the five species. The accuracy for the measurement of total metal was examined from the recovery of metal spiking. The accuracy of the total determination is better than 94% and the precision of speciation is greater than 90%.Most of the studied metals were found in the Fe‐Mn oxides and residual fractions except that Cd, Zn and Cu have significant amounts in the exchangeable, carbonate, and organic matter phases, respectively. Species other than residual fraction are generally considered as potentially available for biota in aquatic systems, and in most cases, metal pollution could be reflected from the variation of fraction distributions.
Persulfate Oxidation and Diphenylcarbazide Photometric Determination of Chromium in Super Alloys
Authors: Tsai Suh‐Jen J. , Chen Shew‐Jiuan , Hwang Huey 
Published: June 2015

AbstractThe quantitative analysis of Cr in super alloys with the presence of a wide variety of elements, Al, B, C, Co, Cu, Hf, Fe, Mn, Mo, Ni, Nb, P, Si, S, Ti, Ta, W, Zr; and trace amounts (a few ppm) of Pb, Se, Bi, Tl and Te has been studied. Persulfate oxidation and diphenylcarbazide photometric method were studied with the purpose of developing a relatively fast and reliable measurement for Cr by wet chemical analysis. The results indicate that the latter is supperior to the former in practical view.In the photometric method, solid sample (0.1g alloys) when treated with HClO4 and H2SO4 took ca. 72 hrs. for complete dissolution. When treated with HCl followed by HNO3, 0.1 g alloys were completely dissolved within 1&1/2; hours. The best experimental conditions for diphenylcarbazide photometric determination of Cr was thus established. Photometric determination of Cr complexes was made at 540 nm.
A Study of the Synthesis of Siloxyquinolines
Authors: Yang M.H. , Liu C.Y. , Wu T.Y. , Guo C.Y. , Chen H.M. , Liu S.L. 
Published: June 2015

AbstractSixteen new 8‐siloxyquinolines and 5‐chloro‐8‐siloxyquinolines were synthesized, Structures of all new compounds were determined by IR, NMR, MASS, and elemental analysis. The factors affecting the silylation reactions are disccussed. From the UV absorption pattern, it is shown that the (p→d)π interaction of the Si‐O bond does exist.
Flavonoids from Hypericum Nagasawai Hayata
Authors: Chen Ming‐Tyan , Wan Chao‐Hsiung , Chen Chiu‐Ming , Kuoh Chang‐Sheng 
Published: June 2015

AbstractFive flavonoids, quercetin, quercitrin, hyperin, orientin, and kaempferol, were isolated from Hypericum nagasawai Hayata. The dominant component is quercitrin.
Acidity and Catalytic Activity of Phosphoric Acid Modified Titanium Oxide Surface
Authors: Cheng Soofin , Lee Jin‐Chur 
Published: June 2015

AbstractBy refluxing the anatase form of TiO2 powder in phosphoric acid, the surface acidity was observed to increase. The amount of acid was determined by n‐butylamine titration in n‐heptane media, and was found to be proportional to the reflux period in phosphoric acid. XRD patterns and IR spectra revealed that the products contained a mixture of the anatase form of TiO2 and titanium phosphate phases. Based on the calculated acid density on the surface, part of the titrant, n‐butylamine penetrated into the titanium phosphate layers. Further investigations using TGA, FT‐IR and TEM techniques along with surface area measurements indicated that the titanium phosphate phase was coated over the TiO2 phase. The surface acidity of the phosphoric acid treated anatase increased due to the substitution of Ti‐OH groups by phosphate groups. Nevertheless, the chemical properties of the resultant surfaces were found to be influenced by the internal anatase phase. The kinetic data on the 2‐propanol dehydration reaction, where the activation energies were found to decrease gradually with an increase in phosphate content, also support these conclusion.
Papain Catalyzed Synthesis of Aspartyl Dipeptides
Authors: Chen Shui‐Tein , Li Kuo‐Fang , Wang Kung‐Tsung 
Published: June 2015

AbstractProcedures have been developed for the preparation of aspartyl containing dipeptides P‐L‐Asp‐AA2 (P=Boc, Cbz and Moz; AA2=Phe‐R or Ala‐R; R=OH, OBzl and OTMB) using papain as a catalyst. The pH dependent of esterase activity by papain catalyzed hydrolysis have been studied. The papain catalyzing reaction can be reacted in aqueous solution, buffer solution or cosolvent system in a thermodynamically controlled approach. A procedure for the conversion of the artificial sweetner precursor P‐Asp‐Phe‐OH to the aspartame is studied also.
Solution Behavior of Aromatic Dipeptides. II. The Mechanistic Aspect of the Coupling Reaction and Conformation Study of Diastereomers
Authors: Chu Yen‐Ho , Chen Shui‐Tein , Wang Kung‐Tsung 
Published: June 2015

AbstractA systematic racemization study of the coupling of Z‐Phe with Phe‐OBzl has been carried in order to determine the optimal conditions. It is found that the L,D diastereomer is the favored product in the coupling of Z‐L‐Phe with D,L‐Phe‐OBzl. A possible mechanism is proposed and elucidated by NMR studies.
Syntheses of Bissydnone Derivatives and Studies of Their Biological Activities
Authors: Tien Hsien‐Ju , Lai Long‐Li , Lee Yao‐Kueng , Chuang Che‐Ping , Yeh Mou‐Yung , Wu Tian‐Shung 
Published: June 2015

AbstractA new method to prepare 3,3′‐ethylenebissydnone (40%), 3,3′‐tetramethylenebissydnone (37%) and 3,3′‐hexamethylenebissydnone (43%) from the corresponding alkylene diamine with paraformaldehyde and potassium cyanide were investigated.Some new bissydone: −3,3′‐trimethylenebissydnone (6%), 3,3′‐(4,4′‐diphenyl)bissydnonylmethane (9%) and 3,3′‐(4,4′‐diphenyi)bissydnonyl ether (28%) were synthesized from the corresponding diamine, paraformaldehyde, sodium bisulfite and potassium cyanide.Biological test of 3,3′‐(4,4′‐diphenyl)bissydnonylmethane shows significant response for coronary dilgtion test, inhibition of collagen induced platelet aggregation and moderate carditropic response. 3,3′‐(4,4′‐Diphenyl)bissydnonyl ether also shows inhibition of collagen induced platelet aggregation and moderate carditropic response.
Selectivity and Stereospecificity in Synthetic Applications of Radical Reactions
Authors: Barton Derek H. R. , Ozbalik Nubar 
Published: June 2015

AbstractThe advantages of radical reactions for Organic Synthesis are summarised. Based on the idea of the disciplined radical, it is now possible to design radical reactions which afford a good yield of a single desired product. The system needs to contain a disciplinary group. In the case of radical reactions involving tin hydrides, it is the weak tin‐hydrogen bond that is the disciplinary group. For the esters of thiohydroxamic acids, the disciplinary group is the thione function. Examples are given. Recent work has involved the design of stereospecific radical reactions. The hindrance around one chiral center is used to control the formation of the second. The ketal of (+)‐ (2R, 3R) tartaric acid gives excellent stereospecificity (≌24:1) with retention of configuration.
The Synthesis of (±)‐α‐Vetispirene Via the Dieckmann Condensation of Ethyl 4‐(2,6‐Dimethyl‐1‐Carbethoxycyclohex‐2‐Enyl)‐Butyrate
Authors: Zee Sheng‐Hsu , Chou Shan‐Yen 
Published: June 2015

AbstractA new process for the synthesis of (±)‐α‐vetispirene (1) starting from 2,4‐dimethyl‐3‐carbethaxycyclohexene (2) is described. The key steps include the stereoselective alkylation of 2 with ethyl 4‐bromo‐butyrate to yield ethyl 4‐(2,6‐dimethyl‐1‐carbethoxycyctohex‐2‐enyl)‐bytyrate (3) and spiroannulation of 3 by Dieckmann condensation to give 2‐carbethoxy‐6,10‐dimethyl spiro[4,5] deca‐6‐en‐1‐one (4).
Some Taxane Derivatives from the Heartwood of Taxus Mairei
Authors: Yeh Ming‐Kuo , Wang Jiunn‐Shyan , Liu Lu‐Peng , Chen Fa‐Ching 
Published: June 2015

AbstractFive Taxane derivatives were isolated from Taxus mairei. Their structures were determined by spectroscopic methods and their physical constants were identical with the literature values. These are Taxa‐4(20), 11‐diene‐2α, 5α, 7β‐tetrol‐5α, 7β, 10β‐triacetate‐2α‐α‐methylbutyrate(I); Taxa‐4(20), 11‐diene‐2α, 5α, 9α, 10β, 13β‐pentol‐2α, 9α, 10β, 13α‐tetraacetate‐5α‐cinnamate(II);Taxa‐4(20), 11‐diene‐5α, 7β, 9α, 10β, 13α‐pentol‐pentaacetate(III); 7β‐acetate‐O‐taxinine A(IV), 1β‐hydroxy‐baccatin‐I(V).
The Crystal Structure of Binuclear Metal Complexes of 7‐Azaindole: Cu2 (CH3CO2)2 (C7H5N2)2(C7H6N2)2 AND Ni2(C7H5N2)4.2DMF
Authors: Peng Shie‐Ming , Lai Chien‐Hsien 
Published: June 2015

AbstractThe crystal and molecular structures have been determined by single‐crystal X‐ray methods for the binuclear metal ions (II) complexes of 7‐azaindole (1H‐pyrrolo [2,3‐b] pyridine, C7H6N2 denoted by HL), Cu2(CH3CO2)2.·L2(HL)2 and Ni2L4.2DMF. The dark green crystal of Cu2(CH3CO2)2L2(HL)2 was found to crystallize in the monoclinic space group P 21/n with a = 9.566(2), b = 12.752(2), c = 12.852(4) Å, β = 99.23(3)0, V = 1547 Å, Z = 2, the final R = 0.062 and Rw = 0.053 for 1488 observations from 2722 unique reflections. The Cu‐Cu distance is 2.747(2), Cu‐N (L−, bridge) is 1.966(7), Cu‐N (HL, axial) is 2.229(8), and Cu‐O is 2.031(6)Å. The red crystal of Ni2L4.2DMF was was found to crystallize in the triclinic space group \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm P \bar 1} $$\end{document} with a = 8.907(5), b = 9.462(2), c = 10.217(2) Å, α = 90.48(2), β = 91.09(3), γ = 110.69(3)0, V =805 Å3, Z = 1, the final R = 0.063 and Rw = 0.069 for 1489 observations from 2834 unique reflections. The Ni‐Ni distance is 2.594(2), Ni‐N is 1.905(7) Å. These two molecules lie on crystllographic inversion centers and exhibit ligand disorder.
In‐Situ Electron Spin Resonance Studies of Polyaniline
Authors: Yang Sze‐Ming , Un Tsair‐Sheng 
Published: June 2015

AbstractIn‐situ electron spin resonance studies of polyaniline at various applied potentials in media of pH 0.49, 2.09, 3.96, anf 9 are reported. The g factor of the esr signal is 2.0036 and does not vary with the applied potential. The peak to peak linewidth decreases to a minimum in a potential range which depends on the pH of the medium. On the other hand, the spin density increases to a maximum in the same potential range. The pH‐potential range where the highly conductive form exists, matches very well the range of narrow linewidth and high spin density of the esr signal. The conductive form of polyaniline consists of highly mobile radical cations or polarons.
Mass Spectra of 2‐ and 6‐Substituted‐3‐Pyrones: Competition Between “RETRO‐DIELS‐ALDER” Fragmentation and Substituent Loss
Authors: Lin Shaw‐Tao , Kuo Yueh‐Hsing , Lee Ming‐Shi 
Published: June 2015

AbstractThe mass spectra of a series of 6‐hydroxy‐3‐pyrones and their derivatives showed a marked dependence upon the nature of the substituent. The “retro‐Diels‐Alder” reaction is the primary decomposition observed for the parent compounds, while the α‐cleavage (substituent loss) competes with the “retro‐Diels‐Alder” reaction for their derivatives. An interpretation of this difference based on the charge location and the thermochemical data is proposed.
Determination of Lead in Heavy Oil by Flow Injection‐Flame Atomic Absorption Spectrometry
Authors: Hwang Jon‐Mau 
Published: June 2015

AbstractA simple on‐line flow injection analysis pre‐concentration technique has been developed. The flow injection system consisted of a 4‐channel peristaltic pump, two 6‐way rotary injection valves containing a microcolumn of Chelex‐100 resin, and a flame atomic absorption spectrometer, allowing the determination of lead at a concentration as low as ppb. The degree of pre‐concentration depended on the injected sample volume. Lead contained in NBS 1634b and other heavy oil samples was determined using the system. Samples were ashed directly in a furnace at 550°C for two hours, dissolved with perchloric acid and then injected into the system. The sampling frequency also depended on the injected sample volume.
The 1,3‐Dipolar Cycloadditions of 3‐Arylsydnone‐4‐Carbonitrile Oxides with Alkenes
Authors: Yeh Mou‐Yung , Chu Wai‐Cheung 
Published: June 2015

Abstract3‐Arylsydnone‐4‐carbonitrile oxides may undergo 1,3‐dipolar cycloadditions with alkenes to produce the corresponding 3‐aryl‐4‐(5‐substituted‐isoxazolin‐3‐yl)sydnones. The direct reaction of 3‐arylsydone‐4‐carbohydroximic acid chlorides with alkenes may also give the same products, and with higher yield.
The Inhibition of the Dissolution of Aluminium in Sodium Hydroxide by Some Organic Phosphorus Compounds
Authors: Mourad M.Y. , Ibrahim E.H. , Al‐Thani M.J. , Nieroukh S.A. 
Published: June 2015

AbstractThe inhibition of the corrosion of aluminium in 1M sodium hydroxide solution by some cyclodiphosphazane derivatives has been studied using hydrogen evolution technique. The results indicate that the additives reduce the corrosion rate. The inhibitory character of these compounds depends upon the concentration of the inhibitor, as well as on its chemical composition.
Spectrophotometric Determination of Titanium in Super Alloys with Diantipyrylmethane and Tiron
Authors: Tsai Suh‐Jen J. , Hwang Huey 
Published: June 2015

AbstractDiantipyrylmethane and tiron spectrophotometric determinations of Ti in the super alloys, Inconel 718 and Inconel 600, have been studied thoroughly. Both reagents formed stable yellow complexes with Ti(IV) in acidic medium. The possible interference from Ni, Fe and Cr was examined. Interference from Fe(III) was eliminated by the reduction of Fe(III) to Fe(II). Cr was removed as chromyl chloride which led to a dramatic improvement in the analytical results for Ti by the tiron photometric method. However, the removal of Cr was not necessary when the diantipyrylmethane method was employed. Consequently, lengthy manipulation of super alloys was required for the tiron determination. These two spectrophotometric methods are compared in terms of simplicity, reproducibility and accuracy.
Dissociation Kinetics of Aqua[(1SR, 4RS, 7RS, 8SR, 11RS, 14RS)‐5,5,7,12,12,14‐Hexamethyl‐1,4,8,11‐Tetraazacyclotetradecane]Copper(II) (Red) Cation in Strongly Acidic, Aqueous Media
Authors: Chen Lien‐Huei , Chung Chung‐Sun 
Published: June 2015

AbstractIn order to investigate the effect of structure variation upon complex dissociation rate constants, the kinetics of the dissociation of (C·rac·5,5,7,12,12,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradecane)copper(II) (red) cation has been examined spectrophotometrically at 25.0°C in 0.1–5.0 M HNO3. The cleavage of the second copper‐nitrogen bond is proposed as the rate‐determining step for this reaction. The possible pathways for the cleavages of the copper‐nitrogen bonds, the factors influencing the dissociation rates, and the factors affecting the relative importance of each of these possible pathways are considered.
Correlation of Nucleophilic Reactivity, Dissociation Constant and Proton Magnetic Resonance of Some 2‐Substituted Naphthols
Authors: Kharaba Mohamed A.H. , Nassar Ahmed M.G. , Youssef Abdel‐Hamid A. , El‐Banna Mohamed M. 
Published: June 2015

AbstractThe rates of reaction of a series of substituted naphthoxides with 1‐chloro‐2,4‐dinitrobenzene in methanol, and the pKa values of the naphthols in 50% methanol have been measured. A linear free energy relationship applies well to these reactions. The rate constants are correlated with the pKa values of the corresponding naphthols via the Brönsted equation giving a β values of 0.94. A linear correlation between ΔH‡ and ΔS‡ is indicative of single mechanism. The nmr spectra of the substituted naphthols have been measured in DMSO·d6.
Oxidation of Benzylic Methyl Groups by Supported MnO2/Al2O3 Oxidant
Authors: Liu Lilian Kao , Lee Yu‐Hsuan , Leu Lee‐Shan 
Published: June 2015

AbstractAn investigation of benzylic oxidations with manganese dioxide supported on neutral alumina has been carried out. Isolation of intermediated products, which is possible in some cases, gives strong support for the reaction mechanism proposed. With 2,6‐di‐tert‐butyl‐4‐methylphenol, 4,4′‐dihydroxy‐3,5,3′,5′‐tetra‐tert‐butyldiphenylmethane,2,6‐di‐tert‐butylphenol and 4‐methyl‐phenol, selective formation of essentially a single product in excellent yield was obtained.