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2009 Volume 20 Issue 7
2009, 20(7): 763-766
doi: 10.1016/j.cclet.2009.02.018
Abstract:
A new free recoverable and reusable mono-alkaloid-type ligand has been synthesized by a simple method. With highly polar groups, the ligand can be recycled and reused eight times to prepare ethyl (2R, 3S)-2, 3-dihydroxy-3-phenylpropionate with high yield and ee via asymmetric dihydroxylation (AD) reaction.
A new free recoverable and reusable mono-alkaloid-type ligand has been synthesized by a simple method. With highly polar groups, the ligand can be recycled and reused eight times to prepare ethyl (2R, 3S)-2, 3-dihydroxy-3-phenylpropionate with high yield and ee via asymmetric dihydroxylation (AD) reaction.
2009, 20(7): 767-770
doi: 10.1016/j.cclet.2009.01.011
Abstract:
A new series of Schiff base esters, 4-(dimethylamino)benzylidene-4'-alkanoyloxyanilines containing even number of carbons at the end group of the molecules (Cn-1 H2n-1COO, n=6, 8, 10, 12, 14, 16, 18) were synthesized. The present compounds were monotropic liquid crystals. It was also found that the end groups of the molecules had effect on the mesomorphic properties.
A new series of Schiff base esters, 4-(dimethylamino)benzylidene-4'-alkanoyloxyanilines containing even number of carbons at the end group of the molecules (Cn-1 H2n-1COO, n=6, 8, 10, 12, 14, 16, 18) were synthesized. The present compounds were monotropic liquid crystals. It was also found that the end groups of the molecules had effect on the mesomorphic properties.
2009, 20(7): 771-774
doi: 10.1016/j.cclet.2009.02.016
Abstract:
A variety of vinamidinium salts were condensated with cyanoacetamide in refluxing methanol that contained sodium methoxide to produce 5-aryl-3-cyano-2-pyridones in good yield. Simple experimental conditions were used to prepare ten different 5-aryl-3-cyano-2-pyridones, four of which are new compounds.
A variety of vinamidinium salts were condensated with cyanoacetamide in refluxing methanol that contained sodium methoxide to produce 5-aryl-3-cyano-2-pyridones in good yield. Simple experimental conditions were used to prepare ten different 5-aryl-3-cyano-2-pyridones, four of which are new compounds.
2009, 20(7): 775-778
doi: 10.1016/j.cclet.2009.03.026
Abstract:
An alternative approach to synthesize pedamide, a key building block of pederin was described. Iodine-induced asymmetric heterocyclization was used as the key step to construct the skeleton, a tetrahydropyran ring with three chiral centers. Brown's asymmetric allylation and Lewis acid-mediated allylation were investigated to introduce chains and chiral alcohols. Sharpless dihydroxylation decorated the side chain. And high optically pure target was obtained by removing the epimers formed in these reactions on column chromatography.
An alternative approach to synthesize pedamide, a key building block of pederin was described. Iodine-induced asymmetric heterocyclization was used as the key step to construct the skeleton, a tetrahydropyran ring with three chiral centers. Brown's asymmetric allylation and Lewis acid-mediated allylation were investigated to introduce chains and chiral alcohols. Sharpless dihydroxylation decorated the side chain. And high optically pure target was obtained by removing the epimers formed in these reactions on column chromatography.
2009, 20(7): 779-783
doi: 10.1016/j.cclet.2009.03.016
Abstract:
Silica supported ammonium dihydrogen phosphate (NH4H2PO4/SiO2) is found to be a recyclable heterogeneous catalyst for a rapid and efficient synthesis of various aryl-14-H-dibenzo[a,j]xanthenes with excellent yields under solvent-free conditions. The present methodology offers several advantages such as excellent yields, simple procedure, short reaction times and milder conditions.
Silica supported ammonium dihydrogen phosphate (NH4H2PO4/SiO2) is found to be a recyclable heterogeneous catalyst for a rapid and efficient synthesis of various aryl-14-H-dibenzo[a,j]xanthenes with excellent yields under solvent-free conditions. The present methodology offers several advantages such as excellent yields, simple procedure, short reaction times and milder conditions.
2009, 20(7): 784-788
doi: 10.1016/j.cclet.2009.02.013
Abstract:
Copper-catalyzed synthesis of N-aryl anthranilic acid derivatives using effective amination of 2-chloro and 2-bromobenzoic acid under microwave irradiation is reported. Some of the advantages of this method are high chemoselectivity, short reaction times, ease of work up procedure and elimination of the need for acid protection.
Copper-catalyzed synthesis of N-aryl anthranilic acid derivatives using effective amination of 2-chloro and 2-bromobenzoic acid under microwave irradiation is reported. Some of the advantages of this method are high chemoselectivity, short reaction times, ease of work up procedure and elimination of the need for acid protection.
2009, 20(7): 789-792
doi: 10.1016/j.cclet.2009.03.014
Abstract:
A series of novel 6-sulfamoyl-4-oxoquinoline-3-carboxylic acids derivatives have been synthesized and screened for HIV integrase inhibition activity. Their structures were confirmed by ESI-MS,1H NMR and 13C NMR.
A series of novel 6-sulfamoyl-4-oxoquinoline-3-carboxylic acids derivatives have been synthesized and screened for HIV integrase inhibition activity. Their structures were confirmed by ESI-MS,1H NMR and 13C NMR.
2009, 20(7): 793-796
doi: 10.1016/j.cclet.2009.03.013
Abstract:
Six new asymmetric thiocarbonohydrazones 3a-3f were synthesized from following steps:firstly hydrazine hydrate reacted with carbon disulfide to form thiocarbonohydrazide (1) under microwave irradiation. Then compound (1) reacted with ketone and different aldehydes step by step to give 3a-3f with excellent yields under solvent-free conditions using microwave irradiation. Their structures have been determined by elemental analysis, IR, MS and 1H NMR data.
Six new asymmetric thiocarbonohydrazones 3a-3f were synthesized from following steps:firstly hydrazine hydrate reacted with carbon disulfide to form thiocarbonohydrazide (1) under microwave irradiation. Then compound (1) reacted with ketone and different aldehydes step by step to give 3a-3f with excellent yields under solvent-free conditions using microwave irradiation. Their structures have been determined by elemental analysis, IR, MS and 1H NMR data.
2009, 20(7): 797-799
doi: 10.1016/j.cclet.2009.02.015
Abstract:
Cinchonine was employed as backbone for the synthesis of novel phosphite compounds with diol substituents. These monophosphinites were provided in one pot with the yields ranged from 63% to 75%. Their structures were confirmed byNMR spectroscopy and HRMS.
Cinchonine was employed as backbone for the synthesis of novel phosphite compounds with diol substituents. These monophosphinites were provided in one pot with the yields ranged from 63% to 75%. Their structures were confirmed byNMR spectroscopy and HRMS.
2009, 20(7): 800-804
doi: 10.1016/j.cclet.2009.01.021
Abstract:
Dinitroterephthalic acid (DNTPA) and diaminoterephthalic acid (DATPA) were prepared in 85% and 75% yields, respectively.These compounds were characterized by using FTIR and 1HNMR. DATPA can be used as a monomer for the preparation of polyesters and polyamides.
Dinitroterephthalic acid (DNTPA) and diaminoterephthalic acid (DATPA) were prepared in 85% and 75% yields, respectively.These compounds were characterized by using FTIR and 1HNMR. DATPA can be used as a monomer for the preparation of polyesters and polyamides.
2009, 20(7): 805-808
doi: 10.1016/j.cclet.2009.03.006
Abstract:
The cycloaddition of N-acyliminium cations with some deactivated alkenes such as α,β-unsaturate ketones and esters has been investigated. In most cases, the N-acyliminium cations produced from 3-hydroxy-2-arylisoindol-1-ones in the presence of BF3·OEt2 could be reacted with α,β-unsaturated ketones and esters to afford stereoselectively the cycloaddition products 6-acylisoindolo[2,1-a] quinolin-11-ones in moderate to high yields.
The cycloaddition of N-acyliminium cations with some deactivated alkenes such as α,β-unsaturate ketones and esters has been investigated. In most cases, the N-acyliminium cations produced from 3-hydroxy-2-arylisoindol-1-ones in the presence of BF3·OEt2 could be reacted with α,β-unsaturated ketones and esters to afford stereoselectively the cycloaddition products 6-acylisoindolo[2,1-a] quinolin-11-ones in moderate to high yields.
2009, 20(7): 809-811
doi: 10.1016/j.cclet.2009.01.041
Abstract:
A series of retinoate and retinamide derivatives were designed, synthesized, and their anti-tumor activities were investigated in NB4 by MTT and flow cytometry assays (FCM). All compounds showed cytotoxicity, especially compounds 1a and 1d exhibited a higher cytotoxicity than other derivatives and all-trans retinoic acid (ATRA). Furthermore, compound 1d could induce NB4 cell lines differentiation efficiently.
A series of retinoate and retinamide derivatives were designed, synthesized, and their anti-tumor activities were investigated in NB4 by MTT and flow cytometry assays (FCM). All compounds showed cytotoxicity, especially compounds 1a and 1d exhibited a higher cytotoxicity than other derivatives and all-trans retinoic acid (ATRA). Furthermore, compound 1d could induce NB4 cell lines differentiation efficiently.
2009, 20(7): 812-814
doi: 10.1016/j.cclet.2009.02.017
Abstract:
A simple, convenient and efficient method for the synthesis of 1,2,4,5-tetrasubstituted imidazole derivatives using benzoin, an aromatic aldehyde, an aromatic amine in the presence of ammonium acetate catalyzed by high surface area SiO2 and induced by free solar thermal energy was reported.
A simple, convenient and efficient method for the synthesis of 1,2,4,5-tetrasubstituted imidazole derivatives using benzoin, an aromatic aldehyde, an aromatic amine in the presence of ammonium acetate catalyzed by high surface area SiO2 and induced by free solar thermal energy was reported.
2009, 20(7): 815-816
doi: 10.1016/j.cclet.2009.02.014
Abstract:
Anovel flavonoid was isolated from the root of Macrothelypteris torresiana (Gaud.) Ching. The structure of the product was identified as 5, 7-dihydroxy-2-(1, 2-isopropyldioxy-4-oxocyclohex-5-enyl)-chromen-4-one on the ground of chemical and spectroscopic methods.
Anovel flavonoid was isolated from the root of Macrothelypteris torresiana (Gaud.) Ching. The structure of the product was identified as 5, 7-dihydroxy-2-(1, 2-isopropyldioxy-4-oxocyclohex-5-enyl)-chromen-4-one on the ground of chemical and spectroscopic methods.
2009, 20(7): 817-819
doi: 10.1016/j.cclet.2009.03.011
Abstract:
The leaves and stems of Quercus variabilis Blume afforded a new cycloartane nortriterpenoid, 3α-acetyloxy-4α, 14α-dimethyl9β, 19-cycloergost-24-oic acid (1), along with five known compounds (2-6). The structure of 1 was elucidated by 1D and 2D NMR and mass spectroscopy.
The leaves and stems of Quercus variabilis Blume afforded a new cycloartane nortriterpenoid, 3α-acetyloxy-4α, 14α-dimethyl9β, 19-cycloergost-24-oic acid (1), along with five known compounds (2-6). The structure of 1 was elucidated by 1D and 2D NMR and mass spectroscopy.
2009, 20(7): 820-822
doi: 10.1016/j.cclet.2009.03.008
Abstract:
A new spirostanol steroidal saponin, named maireioside A (1), together with three known steroidal saponins, hypoglaucin G (2),arisaponin I (3), and diosgenin-3-O-α-L-rhamnopyranosyl (1→4)-[α-L-rhamnopyranosyl (1→2)]-β-D-glucopyranoside (4), were isolated from the rhizomes of Paris mairei. The structure elucidation was accomplished by 1D and 2D NMR methods, HR-ESI-MS,and hydrolysis.
A new spirostanol steroidal saponin, named maireioside A (1), together with three known steroidal saponins, hypoglaucin G (2),arisaponin I (3), and diosgenin-3-O-α-L-rhamnopyranosyl (1→4)-[α-L-rhamnopyranosyl (1→2)]-β-D-glucopyranoside (4), were isolated from the rhizomes of Paris mairei. The structure elucidation was accomplished by 1D and 2D NMR methods, HR-ESI-MS,and hydrolysis.
2009, 20(7): 823-826
doi: 10.1016/j.cclet.2009.03.002
Abstract:
A novel morphine alkaloid, named gindarudine 1 has been isolated from ethanol extract of Stephania glabra tubers, together with four known alkaloids, palmatine, dehydrocorydalmine, stepharanine, and 8-(4'-methoxybenzyl)-xylopinine. Compound 1 was elucidated as 3,6-O,N-detrimethyl-10-hydroxy-1-methoxy-thebaine by means of spectroscopic data including 2D NMR studies.
A novel morphine alkaloid, named gindarudine 1 has been isolated from ethanol extract of Stephania glabra tubers, together with four known alkaloids, palmatine, dehydrocorydalmine, stepharanine, and 8-(4'-methoxybenzyl)-xylopinine. Compound 1 was elucidated as 3,6-O,N-detrimethyl-10-hydroxy-1-methoxy-thebaine by means of spectroscopic data including 2D NMR studies.
2009, 20(7): 827-829
doi: 10.1016/j.cclet.2009.03.022
Abstract:
A novel phenylpropanoid glycoside, Callicarposide A has been isolated from the aerial parts of Callicarpa kwangtungensis Chun. The chemical structure is elucidated on the basis of spectral analysis.
A novel phenylpropanoid glycoside, Callicarposide A has been isolated from the aerial parts of Callicarpa kwangtungensis Chun. The chemical structure is elucidated on the basis of spectral analysis.
2009, 20(7): 830-832
doi: 10.1016/j.cclet.2009.02.008
Abstract:
A new purine nucleoside coupled with an amino acid derivative, N2-(1-methoxycarbonylethyl) guanosine 1, along with β-carbolineand russulaceramide was isolated from the fruiting bodies of Amanita exitialis, a newly described poisonous mushroom.Its structure was elucidated by spectroscopic methods. This is the first report of naturally occurring nucleosides in which an α-amino acid derivative is bonded through its α-amino nitrogen to a nucleobase aglycone by a C-N bond. The new compound was found to be toxic in brine shrimp lethality test (BST).
A new purine nucleoside coupled with an amino acid derivative, N2-(1-methoxycarbonylethyl) guanosine 1, along with β-carbolineand russulaceramide was isolated from the fruiting bodies of Amanita exitialis, a newly described poisonous mushroom.Its structure was elucidated by spectroscopic methods. This is the first report of naturally occurring nucleosides in which an α-amino acid derivative is bonded through its α-amino nitrogen to a nucleobase aglycone by a C-N bond. The new compound was found to be toxic in brine shrimp lethality test (BST).
2009, 20(7): 833-835
doi: 10.1016/j.cclet.2009.01.035
Abstract:
A new bidesmoside triterpenoid saponin, named stauntoside C1 (1) has been isolated from Stauntonia chinensis. Its structure was established by means of spectral and chemical methods.
A new bidesmoside triterpenoid saponin, named stauntoside C1 (1) has been isolated from Stauntonia chinensis. Its structure was established by means of spectral and chemical methods.
2009, 20(7): 836-838
doi: 10.1016/j.cclet.2009.03.023
Abstract:
Two new phenolic glycosides, 2-hydroxy-4-O-β-D-glucopyranosylphenylacetic acid methyl acetate (1) and 2-hydroxy-4-O-β-Dglucopyranosylphenylacetic acid (2) were isolated from the aerial parts of Androsace umbellata. Their structures were elucidated by spectral techniques.
Two new phenolic glycosides, 2-hydroxy-4-O-β-D-glucopyranosylphenylacetic acid methyl acetate (1) and 2-hydroxy-4-O-β-Dglucopyranosylphenylacetic acid (2) were isolated from the aerial parts of Androsace umbellata. Their structures were elucidated by spectral techniques.
2009, 20(7): 839-841
doi: 10.1016/j.cclet.2009.03.004
Abstract:
Two new C-glucoside oxanthrones, 6-methoxyl-10-hydroxyaloin A (1) and 6-methoxyl-10-hydroxyaloin B (2), were isolated from the roots of Rumex gmelini Turcz. Their structures were elucidated on the basis of spectroscopic techniques and chemical means.
Two new C-glucoside oxanthrones, 6-methoxyl-10-hydroxyaloin A (1) and 6-methoxyl-10-hydroxyaloin B (2), were isolated from the roots of Rumex gmelini Turcz. Their structures were elucidated on the basis of spectroscopic techniques and chemical means.
2009, 20(7): 842-844
doi: 10.1016/j.cclet.2009.03.003
Abstract:
Two new prenylflavonoids, named sutchuenmedin A (1) and sutchuenmedin B (2), were isolated from the 70% EtOH extract of Epimedium sutchuenense. Their structures were determined from spectral analysis.
Two new prenylflavonoids, named sutchuenmedin A (1) and sutchuenmedin B (2), were isolated from the 70% EtOH extract of Epimedium sutchuenense. Their structures were determined from spectral analysis.
2009, 20(7): 845-848
doi: 10.1016/j.cclet.2009.01.040
Abstract:
Three kinds of Ni-P electroless coatings were prepared in nickel sulphate solution at different pH values of 4.5, 5.5 and 6.5 with the purpose of ascertaining the influence of pH value on microstructure, internal stress statue and thermal stability of the coatings. Laser curvature (LC) method was used to measure the residual stress level in the coatings. Scanning electronic microscopy (SEM) and transmission electronic microscopy with energy dispersive spectrum (TEM/EDS) were used to examine the surface morphology and internal phase structure of the coatings, respectively. Differential scanning calorimeter (DSC) was used to analyze the phase transformation and thermal stability of the coatings at high temperature. Results showed the Ni-P coating prepared at pH 5.5 with nanocrystal mixed in amorphous structure had the worst thermal stability. The relatively higher stability of Ni-P coatings prepared at pH 4.5 and 6.5 was ascribed to the lower tensile stress level and much finer grain size, respectively. Besides, inverse Hall-Petch effect of annealing strengthening might also contribute to the integrity of Ni-P coating prepared at pH 6.5.
Three kinds of Ni-P electroless coatings were prepared in nickel sulphate solution at different pH values of 4.5, 5.5 and 6.5 with the purpose of ascertaining the influence of pH value on microstructure, internal stress statue and thermal stability of the coatings. Laser curvature (LC) method was used to measure the residual stress level in the coatings. Scanning electronic microscopy (SEM) and transmission electronic microscopy with energy dispersive spectrum (TEM/EDS) were used to examine the surface morphology and internal phase structure of the coatings, respectively. Differential scanning calorimeter (DSC) was used to analyze the phase transformation and thermal stability of the coatings at high temperature. Results showed the Ni-P coating prepared at pH 5.5 with nanocrystal mixed in amorphous structure had the worst thermal stability. The relatively higher stability of Ni-P coatings prepared at pH 4.5 and 6.5 was ascribed to the lower tensile stress level and much finer grain size, respectively. Besides, inverse Hall-Petch effect of annealing strengthening might also contribute to the integrity of Ni-P coating prepared at pH 6.5.
2009, 20(7): 849-851
doi: 10.1016/j.cclet.2009.03.005
Abstract:
The electrochemistry of xanthinol nicotinate (Xan) was studied by cyclic voltammetry at a glassy carbon electrode modified by a gel containing multi-walled carbon nanotubes (MWNTs) and room-temperature ionic liquid of 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6). The modified electrode exhibited good promotion to the electrochemical oxidation of Xan and an ultrasensitive electrochemical method was proposed for the determination of Xan. This method was successfully applied to the determination of Xan in Xan tablets.
The electrochemistry of xanthinol nicotinate (Xan) was studied by cyclic voltammetry at a glassy carbon electrode modified by a gel containing multi-walled carbon nanotubes (MWNTs) and room-temperature ionic liquid of 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6). The modified electrode exhibited good promotion to the electrochemical oxidation of Xan and an ultrasensitive electrochemical method was proposed for the determination of Xan. This method was successfully applied to the determination of Xan in Xan tablets.
2009, 20(7): 852-856
doi: 10.1016/j.cclet.2009.03.001
Abstract:
Micron-sized hollow silica spheres whose shells are made up of mesocellular silica foams (MCFs) have been synthesized by one-pot sol-gel method in benzene/water/P123 emulsion. The material is characterized with SEM, TEM, BET and 29Si MAS NMR.The results show that the MCFs of the unique shell of hollow silica spheres were connected by large windows with a narrow distribution of~10 nm in diameter, the inner space of the hollow sphere is accessible. And the formation mechanism of the hollow silica spheres is proposed.
Micron-sized hollow silica spheres whose shells are made up of mesocellular silica foams (MCFs) have been synthesized by one-pot sol-gel method in benzene/water/P123 emulsion. The material is characterized with SEM, TEM, BET and 29Si MAS NMR.The results show that the MCFs of the unique shell of hollow silica spheres were connected by large windows with a narrow distribution of~10 nm in diameter, the inner space of the hollow sphere is accessible. And the formation mechanism of the hollow silica spheres is proposed.
2009, 20(7): 857-860
doi: 10.1016/j.cclet.2009.02.020
Abstract:
Uniform CePO 4 nanowires with diameter of about 25 nm were synthesized by the water-in-oil microemulsion method at room temperature from cerous chloride, sodium orthophosphate, sodium chloride, cyclohexane, Triton X-100 and cetyltrimethyl ammonium bromide (CTAB). The crystal structure and morphology of the nanowires were characterized by XRD and TEM,respectively. The UV-vis absorption was detected by UV-vis spectrophotometer techniques. The results showed that as-prepared nanowires with the hexagonal phase have obvious quantum confinement effect and semiconductor characteristics. Little sodium chloride could play a positive role on the formation of CePO 4 nanowires at room temperature. The size of the nanowires can be controlled through the joining of sodium chloride.
Uniform CePO 4 nanowires with diameter of about 25 nm were synthesized by the water-in-oil microemulsion method at room temperature from cerous chloride, sodium orthophosphate, sodium chloride, cyclohexane, Triton X-100 and cetyltrimethyl ammonium bromide (CTAB). The crystal structure and morphology of the nanowires were characterized by XRD and TEM,respectively. The UV-vis absorption was detected by UV-vis spectrophotometer techniques. The results showed that as-prepared nanowires with the hexagonal phase have obvious quantum confinement effect and semiconductor characteristics. Little sodium chloride could play a positive role on the formation of CePO 4 nanowires at room temperature. The size of the nanowires can be controlled through the joining of sodium chloride.
2009, 20(7): 861-864
doi: 10.1016/j.cclet.2009.03.030
Abstract:
A self-assembled, (H2O)38 cluster stabilized by a mono-nuclear copper(Ⅱ) complex 1 namely {[Cu(phen)2(CO3)]·7H2O} is characterized by X-ray diffraction studies. The adjacent (H2O)38 clusters connect together resulting in an infinite 2D water layer structure. The water morphology is stable at room temperature, but upon thermal decomposition, the water loss is irreversible.
A self-assembled, (H2O)38 cluster stabilized by a mono-nuclear copper(Ⅱ) complex 1 namely {[Cu(phen)2(CO3)]·7H2O} is characterized by X-ray diffraction studies. The adjacent (H2O)38 clusters connect together resulting in an infinite 2D water layer structure. The water morphology is stable at room temperature, but upon thermal decomposition, the water loss is irreversible.
2009, 20(7): 865-868
doi: 10.1016/j.cclet.2009.01.027
Abstract:
A new zinc acetate catalyst which was prepared from modified activated carbon exhibited extreme activity towards the synthesis of vinyl acetate. The activated carbon was modified by nitric acid, vitriol and peroxyacetic acid (PAA). The effect on specific area,structure, pH and surface acidity groups of carriers by modification was discussed. Amount of carbonyl and carboxyl groups in activated carbon was increased by peroxyacetic acid treatment. The productivity of the new catalyst was 14.58% higher than that of catalyst prepared using untreated activated carbon. The relationship between amount of carbonyl and carboxyl groups (m) and catalyst productivity (P) was P=1.83+2.26×10-3*e3.17m. Reaction mechanism was proposed.
A new zinc acetate catalyst which was prepared from modified activated carbon exhibited extreme activity towards the synthesis of vinyl acetate. The activated carbon was modified by nitric acid, vitriol and peroxyacetic acid (PAA). The effect on specific area,structure, pH and surface acidity groups of carriers by modification was discussed. Amount of carbonyl and carboxyl groups in activated carbon was increased by peroxyacetic acid treatment. The productivity of the new catalyst was 14.58% higher than that of catalyst prepared using untreated activated carbon. The relationship between amount of carbonyl and carboxyl groups (m) and catalyst productivity (P) was P=1.83+2.26×10-3*e3.17m. Reaction mechanism was proposed.
2009, 20(7): 869-872
doi: 10.1016/j.cclet.2009.02.021
Abstract:
Mesoporous tetragonal sulfated zirconia with high surface area and narrow pore-size distribution was prepared using Zr(O-nPr)4as zirconium precursor, sulfuric acid as sulfur source and triblock copolymer poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) (P123) as the template. The samples were characterized by X-ray diffraction, N2 sorption, TEM, and NH3-TPD. A phase transformation from monoclinic sulfated zirconia to tetragonal sulfated zirconia is observed. The product showsstrong acidity.
Mesoporous tetragonal sulfated zirconia with high surface area and narrow pore-size distribution was prepared using Zr(O-nPr)4as zirconium precursor, sulfuric acid as sulfur source and triblock copolymer poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) (P123) as the template. The samples were characterized by X-ray diffraction, N2 sorption, TEM, and NH3-TPD. A phase transformation from monoclinic sulfated zirconia to tetragonal sulfated zirconia is observed. The product showsstrong acidity.
2009, 20(7): 873-876
doi: 10.1016/j.cclet.2009.03.019
Abstract:
In this study, right-handed dicinnamate isosorbide was synthesized via the esterification reaction between optically active isosorbide and cinnamate. The chiral dopant was characterized by FT-IR,1H NMR, elemental analysis, SEM, UV absorption spectrum. After dissolving in a nematic liquid crystal mixture, the chiral dopant exhibited a temperature-dependent solubility in the chiral nematic liquid crystal mixture. Meanwhile, a relatively high value of helical twisting power of the polymerizable chiral dopant was determined. The results show that the chiral dopant has great potential in achieving a polymer stabilized chiral nematic liquid crystal film with a broad-band selective reflection.
In this study, right-handed dicinnamate isosorbide was synthesized via the esterification reaction between optically active isosorbide and cinnamate. The chiral dopant was characterized by FT-IR,1H NMR, elemental analysis, SEM, UV absorption spectrum. After dissolving in a nematic liquid crystal mixture, the chiral dopant exhibited a temperature-dependent solubility in the chiral nematic liquid crystal mixture. Meanwhile, a relatively high value of helical twisting power of the polymerizable chiral dopant was determined. The results show that the chiral dopant has great potential in achieving a polymer stabilized chiral nematic liquid crystal film with a broad-band selective reflection.
Study of the structure and the mechanical properties of dynamically cured PP/MAH-g-SEBS/epoxy blends
2009, 20(7): 877-880
doi: 10.1016/j.cclet.2008.12.054
Abstract:
A new method concerning with the simultaneous reinforcing and toughening of polypropylene (PP) was reported. Dynamical cure of the epoxy resin was successfully applied in the PP/maleic anhydride-grafted styrene-ethylene-butylene-styrene (SEBS) triblock copolymer, and the obtained blends named as dynamically cured PP/MAH-g-SEBS/epoxy blends. The stiffness toughness of the blends are in a good balance, and MAH-g-SEBS was acted as not only an impact modifier but also a compatibilizer.The structure of the dynamically cured PP/MAH-g-SEBS/epoxy blends is the embedding of the epoxy particles by the MAH-SEBS.
A new method concerning with the simultaneous reinforcing and toughening of polypropylene (PP) was reported. Dynamical cure of the epoxy resin was successfully applied in the PP/maleic anhydride-grafted styrene-ethylene-butylene-styrene (SEBS) triblock copolymer, and the obtained blends named as dynamically cured PP/MAH-g-SEBS/epoxy blends. The stiffness toughness of the blends are in a good balance, and MAH-g-SEBS was acted as not only an impact modifier but also a compatibilizer.The structure of the dynamically cured PP/MAH-g-SEBS/epoxy blends is the embedding of the epoxy particles by the MAH-SEBS.
2009, 20(7): 881-884
doi: 10.1016/j.cclet.2009.01.036
Abstract:
A phosphorus-containing monomer (10-oxo-10-hydro-9-oxa-10λ5-phospha-phenanthrene-10-yl)-methyl acrylate (M1) was copolymerized with styrene to give a potential flame retardant copolymer of high thermal stability. The structures of monomer and copolymer were characterized by FT-IR and 1H NMR measurements. The reactivity ratios for free-radical of the monomer (M1) and styrene (M2) were studied. The calculated results are as follows:r1=0.225, r2=0.503; Q1=0.413, e1=0.476; azeotropic point=0.37. TGA and DTG curves indicated that M1 is a potential flame retarding monomer for styrenic polymers.
A phosphorus-containing monomer (10-oxo-10-hydro-9-oxa-10λ5-phospha-phenanthrene-10-yl)-methyl acrylate (M1) was copolymerized with styrene to give a potential flame retardant copolymer of high thermal stability. The structures of monomer and copolymer were characterized by FT-IR and 1H NMR measurements. The reactivity ratios for free-radical of the monomer (M1) and styrene (M2) were studied. The calculated results are as follows:r1=0.225, r2=0.503; Q1=0.413, e1=0.476; azeotropic point=0.37. TGA and DTG curves indicated that M1 is a potential flame retarding monomer for styrenic polymers.
2009, 20(7): 885-888
doi: 10.1016/j.cclet.2009.01.014
Abstract:
Six new thermally stable polyesters (4a-f) were synthesized through the solution polycondensation reaction of 2,5-pyridine dicarbonyldichloride (2) with six aromatic diols in N,N'-dimethyl acetamide (DMAc) solution and in the presence of pyridine as a base. The polycondensation reactions produce a series of new polyesters (4a-f) in high yields, and inherent viscosity between 0.30 and 0.55 dL/g. The resulting polyesters were characterized by elemental analysis, viscosity measurements, thermal gravimetric analysis (TGA and DTG), solubility test, Fourier transform infrared (FT-IR) spectroscopy and gel permeation chromatography (GPC).
Six new thermally stable polyesters (4a-f) were synthesized through the solution polycondensation reaction of 2,5-pyridine dicarbonyldichloride (2) with six aromatic diols in N,N'-dimethyl acetamide (DMAc) solution and in the presence of pyridine as a base. The polycondensation reactions produce a series of new polyesters (4a-f) in high yields, and inherent viscosity between 0.30 and 0.55 dL/g. The resulting polyesters were characterized by elemental analysis, viscosity measurements, thermal gravimetric analysis (TGA and DTG), solubility test, Fourier transform infrared (FT-IR) spectroscopy and gel permeation chromatography (GPC).
