bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Structural Studies on Homo‐and Heterobinuclear Complexes of Cu(II), Ni(II) and Co(II) with Arylideneanthranilic Acid Schiff Bases
Authors: Ibrahim S.A. , El‐Gyar S.A. , El‐Gahami M.A. , Hammam A.M. 
Published: June 2015

AbstractHomo and heterobinuclear complexes of arylidene‐ anthranilic acids with Cu(II), Ni(II) and Co(II) are prepared and characterised by chemical analysis, spectral and X‐ray diffraction techniques as well as conductivity measurements. Two types of homo‐binuclear complexes are formed. The first has the formula M2L2Cl2(H2O)n where M=Cu(II), Ni(II) and Co(II), L = p‐hydroxybenzylideneanthranilic acid (hba), p‐dimethylaminobenzylideneanthranilic acid (daba) and p‐nitrobenzylideneanthranilic acid(nba) and n = 0–3. The second type has the formula M2LCl3(H2O)n in which M is the same as in the first type, L = benzylideneanthranilic acid (ba), (daba) (in cases of Cu(II) and Ni(II)); and n = 1–5.Heterobinuclear complexes having the formula (MLCl2H2O) MCl2(H2O)n are isolated by reaction of Cu(II) binary chelates with Ni(II) and/or Co(II) chlorides. These are also characterized and their structures are elucidated.
Tridensenal, A Sesquiterpene of Novel Skeleton from the Taiwanese Liverwort Bazzania Tridens
Authors: Wu Chia‐Li , Chang Shu‐Jen , Tori Motoo , Furuta Hirosuke , Sumida Aya , Asakawa Yoshinori 
Published: June 2015

AbstractThe sesquiterpene aldehyde, tridensenal, of previously unknown skeleton was isolated from the Taiwanese liverwort Bazzania tridens. The structure of tridensenal was elucidated on the basis of spectral data and proved by synthesis of the diastereomeric mixture.
Reactions of Nadic Anhydride at High Temperatures
Authors: Chen Leo‐Wang , Chern Yaw‐Terng 
Published: June 2015

AbstractThe reaction of nadic anhydride(NA) at high temperature under oxygen or oxygen‐free conditions was investigated in this report in order to understand the cross‐linking behavior of nadic end‐capped polyimides. In this study, 13C‐NMR, mass spectra as well as IR spectroscopy were employed for understanding the reactions involved. In ampule tests, NA was heated after sealing in air or under nitrogen, The dimer, trimer and tetramer of NA were found when heated at 260°C for 30 min. and their possible chemical linkage is shown. More complicated products could be obtained when heating For longer time. The cleavage of double bond was observed when NA was heated at about 340°C and the linkage containing oxygen was found when scaled in air. The molecular weight of product increased in this case.
Solvent Extraction and Spectrophotometric Determination of Uranium Using α‐Benzoin Oxime as Chelating Agent
Authors: Chang Liang Chien , Chen Shou Nan , Gi Hung Jang 
Published: June 2015

AbstractSolvent extraction of uranium by a chloroform solution of α‐benzoin oxime was studied and the formation of uranium‐α‐benzoin oxime complex described. The uranium‐α‐benzoin oxime complex has two maximum absorbance at 350 nm and 427 nm. A constant absorbance was obtained for 1 × 10−3 M uranium when the concentration of α‐benzoin oxime was higher than 1.2 × 10−2 M. Ions of Ag+, Fe3+, V5+, Cu2+, and W6+ were found to have interference.A solution containing 0.1–10 mg uranium at pH 1.6–6.8 was extracted with 1 × 10−3 M −2 × 10−3 M α‐benzoin oxime solution in chloroform. With single extraction, the maximum amount of uranium passing into organic layer was at least 98%. Under this condition the presence of diverse ions except V5+ does not significantly interfere the extraction of uranium.
Preparation of 3,4,5,3′‐Tetramethoxy‐4′,5′‐Methylenedioxybenzophenone and Bis‐(3‐Methoxy‐4,5‐Methylenedioxy)‐Benzophenone
Authors: Zee Sheng‐Hsu , Chou Shan‐Yen 
Published: June 2015

AbstractThe preparation of 3,4,5,3′‐tetramethoxy‐4′,5′‐methylenedioxybenzophenone (I) and bis‐(3‐methoxy‐4,5‐methylenedioxy)‐benzophenone(II) were reported. The synthesis of these compounds were accomplished using two separate synthetic routes starting from gallic add and its derivatives to the corresponding benzils. Both compound I and II were obtained by benzilic acid rearrangement of the benzils and followed by an oxidative decarboxylation.
Binuclear Complexes. II. Electron Paramagnetic Resonance Study of Binuclear Copper Complexes with α‐Diimine Ligand
Authors: Wen‐Jwuwang  , Chen Cheu‐Pyeng 
Published: June 2015

AbstractA series of biouclear copper (II) complexes containing a‐diimine ligand has been synthesized and characterized by electron paramagnetic resonance spectroscopy. The copper complexes of the form [Cu(dien)D](ClO4)2 or [Cu2(dien)2L](CIO4)4, where dien is diethylenetriamine, L' is monodentate ligand and L is bridging ligand, were studied. The EPR spectra were recorded in solution and frozen glassy solution. In the frozen solution spectra, the values of G‖ are in the range of 2.10 to 2.20, and the g⊥ are in the range of 2.03 to 2.06. Furthesmore, the values of A‖ are in the range of 170 to 188 gauss, and the A ⊥ are in the range of 17 to 32 gauss. The data indicate that the structure of Cu(II) complexes is axial symmetry in square pyramidal form.
Two New Resolution Processes for the Preparation of (+)‐S‐2‐(6‐Methoxy‐2‐Naphthyl)Propionic Acid (d‐Naproxen)
Authors: Chang Kuo‐Mien , Wu Shihn‐Sheng , Yhn Shiow‐Ling , Wang Yi‐Fong 
Published: June 2015

AbstractTwo new chemical resolution processes have been developed for the preparation of ( + )‐S‐2‐(6‐methoxy‐2‐naphthyl)‐propionic acid (d‐Naproxen). One is via the diastereoselective aminolysis of amide 4 with piperidine and the other is via the selective stoichiometric crystallization of amide 5
Synthesis of Some New Pyrazolo[3,4‐b]Pyridlne and Pyrazolo[3,4‐d]Pyrimidine Derivatives1
Authors: Younes Mansour I. , Abbas Hessan H. , Metwally Saoud A.M. 
Published: June 2015

AbstractSeveral pyrazolo[3,4‐b]pyridine (3,4) and pyrazolo‐[3,4‐d]pyrimidine (5‐13) derivatives were prepared using 5‐amino‐l‐(5‐ethyl‐5H‐1,2,4‐triazino[5,6‐b]‐indol‐3‐yl)‐lH‐pyrazole‐4‐carbonitrile (2). The pyridine derivatives 3 and 4 were obtained by reaction of 2 with malononitrile and ethyl cyanoacetate, respectively, while pyrimidine analogs 5‐13 were synthesized cither by a one‐step or multi‐step sequence.
Electrochemical and Spectral Studies of Sterically Hindered Water‐Soluble Iron Tetrakis(Sulfonatomesityl)Porphine
Authors: Cheng Shu‐Hua , Chen Yu‐Shen , Su Y. Oliver 
Published: June 2015

AbstractSterically hindered water‐soluble iron(III) tetrakis(sulfonatomesityl)porphine (FeTSMP) exists exclusively in its monomer form in neutral and basic aqueous solutions. The acid dissociation constant (pKa) for FeIIITSMP is 6.6. The FeIII/IITSMP couple has a formal reduction potential at −0.22 V (vs. Ag/AgCl) in an acidic buffer solution. The E°‐pH diagram shows that E° is independent of pH until the pH is larger than the pKa. The acid dissociation constant for FeIITSMP is 11.7. The redox potential of FeIII/IITSMP shifts positively when imidazole is present, indicating the ligation of imidazole to FeIITSMP. At pH 4.0 and 10.2 buffer solutions, two imidazoles are found to ligate at the iron(III) center with β2 = 104.7 and 104.1, respectively. The E°‐pH diagram indicates that the pKa of (ImH)2FeIIITSMP is 11.3 at 0.03 M imidazole solution. The oxidation of FeIIITSMP could involve two one‐electron transfer processes, namely, one electron oxidation at the iron center, while another at the porphyrin ring. The two one‐electron oxidations are found to overlap at pH = 5.5 and separate as the pH increases by shifting of the potential at the iron center, which is pH dependent. The radical cation of porphyrin ring is not stable and decomposes rapidly in water.
Novel W(CO)6‐Promoted C‐S Bond Cleavage Reactions of Dithianes. X‐Ray Structure of 9,9′:9,9′‐Terfluorene
Authors: Kuo Chi‐Hong , Lnh Tien‐Yau , Cheng Ming‐Chu , Peng Shie‐Ming 
Published: June 2015

AbstractThe reactions of dithianes with W(CO)6 in refluxing chlorobenzene give dimeric alkenes and their reduced products; fluorenone derivative yielding trimer 8. A radical mechanism is suggested. The structure of 8 has been determined by a single‐crystal X‐ray diffraction study. Crystal data: P21/n; a = 11.948(5), b = 16.8795(14), c = 13.491(6) Å, β = 105.03(3)°, Z = 4, V = 2628(2) Å3; RF = 0.061, RWF = 0.051 for 2142 reflections and 353 variables.
Facile Synthesis of Biologically Active Peptides Using Phase Transfer Reagents as C‐Terminal Protecting Group
Authors: Chen Shui‐Tein , Wang Kung‐Tsung 
Published: June 2015

AbstractPhase‐transfer reagents (basic, neutral, and acidic) can temporarily protect carboxyl groups by salt formation of C‐terminal free amino acids or peptides during peptide synthesis. The salts of amino acids or peptides behave as RNH2 rather than RNH3+. At least there is a sufficient concentration of the free amine to act as a nucleophile under the reaction conditions. Many biologically active small peptides have been synthesized by this procedure. No racemization was detected. Unusual amino acids such as β‐alanine, and ε‐aminohexanoic acid can be incorporated into peptides in high yields.
Hydrogenation of Carbon Dioxide on Iron Manganese Catalysts
Authors: Kuci Chi‐Kung , Chen Wen‐Shing , Lee Min‐Dar 
Published: June 2015

AbstractThe synthesis of hydrocarbons from hydrogenation of carbon dioxide has been studied on a series of coprecipitated iron‐manganese catalysts. Kinetic measurements, X‐ray diffraction, Mössbauer spectroscopy, and temperature‐programmed reaction of adsorbed species were used for activity tests and catalyst characterizations. The results showed that the yields of low‐carbon olefins decrease, whereas the amount of methane increases with increasing manganese content in catalysts. The conversion to hydrocarbons is suppressed by the reverse water‐gas shift (RWGS) reaction equilibrium. Mössbauer spectra and XRD patterns of catalysts after reaction indicate that catalysts are severely oxidized; it is speculated that the olefin producing surface structure in CO hydrogenation may be destroyed by this oxidation. A pulse‐reactor study of the Boudouard reaction showed that manganese has the effect of suppressing CO dissociation and thus decreasing carbon content on catalysts. For CO2 hydrogenation, the affinity to carbon on catalysts is important; therefore manganese is not a good promoter. Among all catalysts tested, pure iron has the best selectivity to olefinic and long‐chain hydrocarbons.
Mössbauer Spectroscopic Studies of Ferrocenylaldimines and their TCNQ Complexes
Authors: Lee Chin‐Jhan , Wei Ho‐Hsiang 
Published: June 2015

AbstractA series of ferrocenylaldimines (Fc‐CH=N‐R) has been prepared by Schiff base condensation of formylferrocene with polyacenylamines RNH2 where R = naphthyl, 5,6,7,8‐tetrahydronaphthyl, anthracenyl, and pyrenyl groups. This step was followed by oxidation with TCNQ to give [Fc‐CH = N‐R][TCNQ]2 salts. The electronic state of iron in these compounds was investigated by means of57Fe Mössbauer spectroscopy.
Improved Method of Extraction and High‐Performance Liquid Chromatographic Separation of Ganoderic Acids from Ganoderma Lucidum
Authors: Sye Wen‐Fa 
Published: June 2015

AbstractA rapid and efficient method is described for the extraction of ganoderic acids from Ganodemia lucidum by means of a small Sep‐Pak C18 cartridge. The application of high‐performance liquid chromatography to determine the chemical compositions of strains of Ganoderma lucidum is also reported.
Synthesis of 1‐phenyi‐1H‐tetrazolo[4,5‐d]tetrazole and 5‐aryl‐1‐(4‐bromophenyl)‐1,2,4‐triazolo[4,3‐d]tetrazoles
Authors: Moustafa M. A. A. , Ismaiel A. M. , Eisa H. M. , El‐Emam A. A. 
Published: June 2015

Abstractl‐Phenyl‐lH‐tetrazol‐5‐yIhydrazine (2) was reacted with nitrous acid to yield 1‐phenyl‐lH‐tetrazolo[4,5‐d]tetrazole (3). l‐Arylidene‐2‐(l‐phenyl‐lH‐tetrazol‐5‐yl)hydrazines (4) were generally reactive towards electrophilic reagents. When treated with bromine in acetic acid, 4 yielded mixtures of 1‐arylidene‐2‐[1‐(4‐bromophenyl)‐lH‐tetrazol‐5‐yl]hydrazines (5a‐d) and 2‐[1‐(4‐bromophenyl)‐lH‐tetrazol‐5‐yl]hydrazidic bromides (6a‐d). Solvolysis of 6a‐d in aqueous acetone yielded 5‐aryl‐1‐(4‐bromophenyl)‐1,2,4‐triazolo[4,3‐d]tetrazoles (7a‐d). The structures of the synthesized compounds were confirmed on the basis of elemental analysis, IR and 1H NMR data.
The Application of Cryptand 22 as a Bifunctional Stationary Phase for Ion Chromatography
Authors: Chen Sih‐Jen , Shih Jeng‐Shong 
Published: June 2015

AbstractPoly (styrene/divinyl benzene) with cryptand 22 as an anchoring group was synthesized and applied as a bifunctional packing material for the separation of both cations and anions. At pH < 2, the resin can be protonated and applied as an anion exchanger for the separation of anions; with water as eluent, inorganic anions such as F−, Cl−, Br−, NO3−”, I− were well separated. After deprotonation at pH> 10, the resin became a cation exchanger and successfully separated alkali metal ions such as Li+, K+ and Cs+ with methanol as eluent. The effects of solvents, flow rate and temperature on the separation of various ions were also investigated.
Low‐Pressure Chemical Vapor Deposition of Silicon Carbide Thin Films from Organopolysilanes
Authors: Chiu Hsin‐Tien , Wu Pei‐Fang 
Published: June 2015

Abstract(Me3Si)2SiMe2, (Me3Si)3SiMe and (Me3Si)4Si were used as precursors for the deposition of polycrystalline β‐SiC thin films on silicon substrates at 1000–1200°C in a low‐pressure hot‐wall chemical vapor deposition reactor. The thin films were analyzed by X‐ray diffraction, scanning electron microscopy and X‐ray photoelectron spectroscopy.
Tricarbonyl(dialkylamidocyclohexa‐1,3‐diene)iron: Preparation, Isomerization and Stereochemistry
Authors: Ong Chi Wi , Hwang Wen Shu , Liou Wen Tzong 
Published: June 2015

AbstractThe direct reaction of iron pentacarbonyl with diethylamidocyclohexadiene gave three isomeric tricarbonyliron complexes, 1, 2 and 3. Only 1 isomerized to give 2 under acidic conditions, whereas 3 remained unchanged. The chemical properties of the tricarbonyl(amidocyclohexadiene)iron complexes differed from those of the tricarbonyl(carboxycyclohexadiene)iron complexes. Complex 3 which underwent no hydride abstraction with triphenylmethyl hexafluorophosphate, has an exo stereochemistry.
Synthesis of the Sex Attractant (7Z,11Z)‐Hexadecadienal of the Citrus Leafminer Moth, Phyliocnietis Citrella Stainton
Authors: Yea Yao‐Pin , Chang Chin‐Yuang 
Published: June 2015

AbstractA component (7Z,11Z)‐hexadecadienal of the sex attractant of the citrus leafminer moth was synthesized through a new (C6 + C3) + C7 approach.
Adsorption Geometry of 4‐Cyanopyridine on Ag Electrode by SERS
Authors: Lan Yueh Hsen , Chang Hua 
Published: June 2015

AbstractThe adsorption of 4‐cyanopyridine (PyCN) on Ag electrode has been studied by surface‐enhanced Raman scattering. The Raman band of the CN group is at 2240 or 2100 cm−1; it appears in various ranges of potential. When a series of potentials was applied stepwise to the electrode, the growing and vanishing of both bands was monitored by an optical multichannel analyzer with a time resolution 1 s or less. Some information about the kinetics of the adsorption and desorption of CN group and about the adsorption geometry of PyCN on the electrode was obtained.
Mass Spectra of Furfuryl Aldoximes and Ketoximes
Authors: Lin Shaw‐Tao , Kuo Yueh‐Hsiung , Lin Yun‐Lian 
Published: June 2015

AbstractThe mass spectra of 8 furfuryl aldoximes and ketoximes were studied under EI and CI conditions. Complicated fragmentation patterns were obtained in EI conditions, including formation of a furfuryl cation radical, furfuryl cation, and [M‐17]+. The relatively simple patterns of cleavage resulted in few major ion peaks contributed from the adducts, protonation products, and dehydration products under CH4‐CI and NH3‐CI conditions. Comparison with the spectra of their isomeric amides indicated no evidence that the isomerization took place from oximes before fragmentation in both ionization methods.
Stereoselective Synthesis of (+)‐Peperomin C
Authors: Zee Sheng‐Hsu , Chou Shan‐Yen 
Published: June 2015

AbstractThe stereoselective synthesis of peperomin C is reported. The key steps include the stereoselective alkylation of the substituted diphenylmethyl group to the r‐butyrolactone ring and transformation of the carbonyl group to the other side in the butyrolactone ring by reduction of the lactone carbonyl followed by degradative oxidation.
The Constituents of Cynanchum Taiwanianum
Authors: Chen Zong‐Shiow , Lai Jeng‐Shiow , Kao Yueh‐Hsiung 
Published: June 2015

AbstractThe isolation and identification of eleven crystalline components from the aerial part of Cynanchum taiwanianum Yamazaki (Asclepiadaceae) are described. Their structures were determined on the basis of spectral evidence and chemical transformation. Besides caffeic acid, β‐amyrin, and methyl phaeophorbide a, the isolated flavonoid components are classified into two groups, i.e. kaempferol derivatives (kaempferol, astragalin, afzelin, trifolin) and quercetin derivatives (quercetin, isoquercitrin, quercitrin, hyperin).
Isolation of a Bioactive Sterol from the Soft Coral Lobophytum Mirabile
Authors: Sheu Jyh‐Horng , Veh Tsuey‐Hua 
Published: June 2015

AbstractA cytotoxic sterol, 24ξ‐melhylcholestane‐3β,5α,6β,25‐tetrol 25‐monoacetate (1) was isolated from the soft coral Lobophytum mirabile. This polar sterol showed moderate cytotoxicity toward P388 cells.
Asymmetric Diels‐Alder Reactions of Chiral Menthyl α‐Sulfinylacrylates
Authors: Yang Teng‐Kuei , Lee Dong‐Sheng , Teng Tsung‐Fan , Jong Ting‐Ting , Chien Mei‐Yueh 
Published: June 2015

AbstractIntroducing two chiral auxiliaries, sulfoxide and menthol, into an acrylate would have either matched or mismatched pair systems. The presence of chiral menthol in α‐sulfinylacrylates can change the diastereoselectivity from 24% d.e. to a single diastereomer by manipulation of the double asymmetric strategy.
Enantioselective Synthesis of N‐[(S)‐Ethoxycarbonyl‐3‐phenylpropyl]‐L‐alanyl‐L‐proline from Chiral Synthon Prepared Enzymatically; A Practical Method for Large‐Scale Synthesis
Authors: Tseng Tsung‐Chin , Duo Tsai‐Hui , Wang Yi‐Fong 
Published: June 2015

AbstractEfficient procedures have been developed for the stereospecific synthesis of Angiotensin‐converting enzyme inhibitor, Enalapril. The starting material, (R)‐2‐hydroxy‐4‐phenylbutyronitrile, is prepared from lipase‐catalyzed acetylation. This process is useful for multigram‐scale synthesis.
Intramolecular Diels‐Alder Reactions of Furans with Allenyl Ethers. Formation of Indanone and Tetralone
Authors: Lin Chu‐Chung , Chen Liang‐Huei , Wu Hsien‐Jen 
Published: June 2015

AbstractThe intramolecular Diels‐Alder reactions of the furans 3, 11a and 11b produced indanone 6 and tetralones 14a and 14b respectively, presumably via the corresponding allenyl ethers 4, 12a and 12b and the intramolecular cycloadducts 5, 13a and 13b.
Probing the Double Bond and Phase Properties of Natural Lipid Dispersions by Cross Polarization/Magic Angle Spinning 13C NMR
Authors: Chi Lang‐Ming , Hsieh Chemg‐Huain , Wu Wen‐Guey 
Published: June 2015

AbstractSolid‐state high resolution 13C NMR spectra of bovine brain sulfatide, egg sphingomyelin, egg phosphatidylcholine, and cholesterol/phosphatidylcholine dispersions were obtained by the cross‐polarization/magic angle spinning (CP/MAS) method as functions of contact time, temperature and composition. Quantitative analysis of the chemical shift and linewidth data indicate that in the liquid‐crystalline state the hydrocarbon chains of sulfatide are packed less orderly than those of sphingomyelin, and that there are two or more conformers for the ceramide residues of natural sphingolipids. The fatty acid double bond showed higher mobility than that of sphingosine as monitored by the signal intensity profiles as a function of contact time. The same approach was used to study the coexisting Lα (liquid‐crystalline phase) and β (cholesterol‐rich characterized phase) two‐phase region of cholesterol/phosphatidylcholine mixtures. Without isotope enrichment, structural and phase properties of natural lipid dispersions can be obtained easily by monitoring the chemical shift, the signal intensity and the linewidth of l3C NMR spectra.
Electron Delocalization in a New Mixed‐Valence σ‐Bridged Biferrocenium Cation
Authors: Dong Teng‐Yuan , Lee Ting‐Yu 
Published: June 2015

AbstractThe physical properties of mixed‐valence 1,3‐diferrocenyl‐propan‐1‐one (1) are reported. The Mössbauer spectrum of mixed‐valence cation 1 at 300 K shows two doublets, one for a Fe11 metallocene (ΔEQ = 2.192 mm s−1) and the other for a FeIII metallocene (ΔEO = 0.179 mm s−1) Thus, the thermal electron‐transfer rate in 1 is less than the time scale of the Mössbauer technique (∼107 s−1). Furthermore, the NMR, electrochemical IR, and near‐IR data conclusively indicate that there is no significant interaction between the two ferrocenyl moieties.
Application of a Cation‐Exchange Membrane to Determine Cations of Trace Metals in River Water
Authors: Hung Jia‐Jang , Wong Chih‐Chich 
Published: June 2015

AbstractDonnan‐membrane‐equilibrium graphite‐furnace atomic‐absorption spectrophotometry (DME‐GFAAS) has been developed to determine cations of trace metals in river water. The method employs a cation‐exchange membrane to separate metal cations from their complexes; both total and cationic forms of metals were determined by means of GFAAS. The sensitivity of the method for the measurement of trace metal cations is determined by the detection limits of GFAAS for the metals of interest. Comparable concentrations of metal cations in water from NBS and from the Erhjen river were obtained between the DME‐GFAAS and calculated (WATEQ4F) methods, indicating that the developed method is promising for natural fresh waters. The effect of pH on the distribution of metal cation in the NBS river water is significant for Cu and Pb; concentrations of these cations increase with decreasing pH. However, the concentrations of Cd and Zn cations do not vary with pH except that the concentration of the Zn cation decreases significantly as the pH value increases beyond 9. The method was applied to measure the capacity of complexing Cu in Chung‐Lu river water, which was estimated to be 2.3 μM.
Reaction of Trimethylbenzene over Alumina‐Pillared Montmorillonite
Authors: Ko An‐Nan , Chemg Hsin‐Chuan 
Published: June 2015

AbstractThe reaction of trimethylbenzene (TMB) over alumina‐pillared montmorillonite (Al‐PM) had been investigated in a fixed‐bed flow reactor at 300 °C and atmospheric pressure. Al‐PM calcined in the range 300‐500 °C exhibited decreased layer distance, surface area and acid amount. The strong acid sites of Al‐PM calcined at 500 °C were greatly diminished according to measurements of ammonia temperature‐programmed desorption. Under our conditions the reaction proceeded mainly via isomerization and disproportionation with little dealkylation. The conversion of reactant decreased in the order 1,2,3‐TMB ≥ 1,2,4‐TMB > 1,3,5‐TMB and the selectivity of isomerization in the order 1,2,3‐TMB > 1,3,5‐TMB > 1,2,4‐TMB, corresponding to the order of diminishing thermal instability. Both the catalytic activity and the selectivity ratio of disproportionation to isomerization decreased with increased calcined temperature and time‐on‐stream. o‐Xylene content in the total xylene produced from 1,2,4‐TMB or 1,2,3‐TMB greatly exceeded the composition at thermodynamic equilibrium. These results arc consistent with the decrease of both the strong acid sites and the pore size of Al‐PM which exhibits the restricted transition state selectivity.
Industrial Protease “Alcalase” as a Catalyst in Organic Synthesis: Resolution of Natural and Unnatural Amino Acids
Authors: Chen Shui‐Tein , Hsiao Shu‐Chyong , Chiou Aih‐Jing , Wu Shih‐Hsiung , Wang Kung‐Tsung 
Published: June 2015

AbstractProcedures have been developed for the resolution of natural and unnatural amino acids using soluble or immobilized industrial enzyme “Alcalase” as catalyst. The specificity of enzyme on different amino acids and the stability of both free and immobilized enzyme have been studied.