Oxidation of aliphatic and aromatic halides by N-oxide functionalities supported on 4- vinyl pyridine, (4-VP), grafted cellulose is reported in the present manuscript. Synthesis of graft copolymer of cellulose and pol...Oxidation of aliphatic and aromatic halides by N-oxide functionalities supported on 4- vinyl pyridine, (4-VP), grafted cellulose is reported in the present manuscript. Synthesis of graft copolymer of cellulose and poly 4-vinyl pyridine, poly(4-VP), has been carried out using ceric ions as redox initiator. Post-grafting treatment of CellO-g-poly (4-VP) with 30% H2O2 in acetic acid gives Cellulose-g-poly (4-VP) N-oxide, the polymeric supported oxidizing reagent. The polymeric support, CellO-g-poly (4-VP) N-oxide, has been used for oxidation reactions of different alkyl / aryl halide such as 1-bromo-3-methyl butane, 2-bromo propane,1-bromo heptane and benzyl chloride. The polymeric reagent was characterized by IR and thermo-gravimetric analysis. The oxidized products were characterized by FTIR and H1NMR spectral methods. The reagent was reused for the oxidation of a fresh alkyl / aryl halides and it was observed that the polymeric reagent oxidizes the compounds successfully but with little lower product yield.展开更多
The hydrogenation of toluidines catalyzed by silica-supported carboxymethyl cellulose platinum complex forms methylcyclohexlamines in high yields, such as m-toluidine to 3-methylcyclohexylamine, o-toluidine to 2-methy...The hydrogenation of toluidines catalyzed by silica-supported carboxymethyl cellulose platinum complex forms methylcyclohexlamines in high yields, such as m-toluidine to 3-methylcyclohexylamine, o-toluidine to 2-methylcyclohexylamine, and p-toluidine to 4-methylcyclohexylamine in 97%, 96.7% and 98.2% yields, respectively, at 30 ℃ and under atmospheric hydrogen pressure. The yields were remarkably affected by the Pt content in the complex, the kind of solvent and the reaction temperature. The catalyst was very stable and could be reused several times without remarkable change in the catalytic activity.展开更多
A silica-supported carboxymethylcellulose platinum complex (abbreviated as SiO_2-CMC-Pt) has been prepared and characterized by XPS. Its catalytic properties for hydro-genation of aromatic compounds were studied. The ...A silica-supported carboxymethylcellulose platinum complex (abbreviated as SiO_2-CMC-Pt) has been prepared and characterized by XPS. Its catalytic properties for hydro-genation of aromatic compounds were studied. The results showed that this catalystcould catalyze the hydrogenation of phenol, anisol, p-cresol, benzene and toluene to cyclo-hexanol, cyclohexyl methyl ether, p-methyl cyclohexanol, cyclohexane and methylcyclo-hexane, respectively in 100% yield at 30℃ and 1 atm. In the hydrogenation of phenol,COO/Pt ratio in SiO_2-CMC-Pt has much influence on the initial hydrogenation rate andthe selectivity for the intermediate product, cyclohexanone. The highest initial rate andthe highest yield of cyclohexanone both occur at COO/Pt ratio of 6. The complex is stableduring the reaction and can be used repeatedly.展开更多
Through exploring potential analogies between cotton seed trichomes （or cotton fiber） and arabidopsis shoot trichomes we discovered that CesAs from either the primary or secondary wall phylogenetic clades can suppor...Through exploring potential analogies between cotton seed trichomes （or cotton fiber） and arabidopsis shoot trichomes we discovered that CesAs from either the primary or secondary wall phylogenetic clades can support secondary wall thickening. CesA genes that typically support primary wall synthesis, AtCesA 1,2,3,5, and 6, underpin expansion and secondary wall thickening of arabidopsis shoot trichomes. In contrast, apparent orthologs of CesA genes that support secondary wall synthesis in arabidopsis xylem, AtCesA4,7, and 8, are up-regulated for cotton fiber secondary wall deposition. These conclusions arose from： （a） analyzing the expression of CesA genes in arabidopsis shoot trichomes; （b） observing birefringent secondary walls in arabidopsis shoot trichomes with mutations in AtCesA4, 7, or 8; （c） assaying up-regulated genes during different stages of cotton fiber development; and （d） comparing genes that were co.expressed with primary or secondary wall CesAs in arabidopsis with genes up- regulated in arabidopsis trichomes, arabidopsis secondary xylem, or cotton fiber during primary or secondary wall deposition. Cumulatively, the data show that： （a） the xylem of arabidopsis provides the best model for secondary wall cellulose synthesis in cotton fiber; and （b） CesA genes within a ＂cell wall toolbox＂ are used in diverse ways for the construction of particular specialized cell walls.展开更多
The Knoevenagel reaction of aromatic aldehydes with malononitrile and ethyl cyanoacetate proceeds smoothly in the presence of carboxymethyl cellulose supported triethylenetetramine as catalyst in the 95% ethanol to af...The Knoevenagel reaction of aromatic aldehydes with malononitrile and ethyl cyanoacetate proceeds smoothly in the presence of carboxymethyl cellulose supported triethylenetetramine as catalyst in the 95% ethanol to afford the desired E-isomers of the corresponding alkenes in yield of 74%～96% and good purity. The results confirm that the catalyst can offer definite advantages of good activity , easy separation, mild reaction condition and high yields. Moreover, it can be reused for not less than 5 runs.展开更多
文摘Oxidation of aliphatic and aromatic halides by N-oxide functionalities supported on 4- vinyl pyridine, (4-VP), grafted cellulose is reported in the present manuscript. Synthesis of graft copolymer of cellulose and poly 4-vinyl pyridine, poly(4-VP), has been carried out using ceric ions as redox initiator. Post-grafting treatment of CellO-g-poly (4-VP) with 30% H2O2 in acetic acid gives Cellulose-g-poly (4-VP) N-oxide, the polymeric supported oxidizing reagent. The polymeric support, CellO-g-poly (4-VP) N-oxide, has been used for oxidation reactions of different alkyl / aryl halide such as 1-bromo-3-methyl butane, 2-bromo propane,1-bromo heptane and benzyl chloride. The polymeric reagent was characterized by IR and thermo-gravimetric analysis. The oxidized products were characterized by FTIR and H1NMR spectral methods. The reagent was reused for the oxidation of a fresh alkyl / aryl halides and it was observed that the polymeric reagent oxidizes the compounds successfully but with little lower product yield.
文摘The hydrogenation of toluidines catalyzed by silica-supported carboxymethyl cellulose platinum complex forms methylcyclohexlamines in high yields, such as m-toluidine to 3-methylcyclohexylamine, o-toluidine to 2-methylcyclohexylamine, and p-toluidine to 4-methylcyclohexylamine in 97%, 96.7% and 98.2% yields, respectively, at 30 ℃ and under atmospheric hydrogen pressure. The yields were remarkably affected by the Pt content in the complex, the kind of solvent and the reaction temperature. The catalyst was very stable and could be reused several times without remarkable change in the catalytic activity.
文摘A silica-supported carboxymethylcellulose platinum complex (abbreviated as SiO_2-CMC-Pt) has been prepared and characterized by XPS. Its catalytic properties for hydro-genation of aromatic compounds were studied. The results showed that this catalystcould catalyze the hydrogenation of phenol, anisol, p-cresol, benzene and toluene to cyclo-hexanol, cyclohexyl methyl ether, p-methyl cyclohexanol, cyclohexane and methylcyclo-hexane, respectively in 100% yield at 30℃ and 1 atm. In the hydrogenation of phenol,COO/Pt ratio in SiO_2-CMC-Pt has much influence on the initial hydrogenation rate andthe selectivity for the intermediate product, cyclohexanone. The highest initial rate andthe highest yield of cyclohexanone both occur at COO/Pt ratio of 6. The complex is stableduring the reaction and can be used repeatedly.
基金Research support was provided by Cotton Incorporated, Cary, NC and the NSF Plant Genome Program
文摘Through exploring potential analogies between cotton seed trichomes （or cotton fiber） and arabidopsis shoot trichomes we discovered that CesAs from either the primary or secondary wall phylogenetic clades can support secondary wall thickening. CesA genes that typically support primary wall synthesis, AtCesA 1,2,3,5, and 6, underpin expansion and secondary wall thickening of arabidopsis shoot trichomes. In contrast, apparent orthologs of CesA genes that support secondary wall synthesis in arabidopsis xylem, AtCesA4,7, and 8, are up-regulated for cotton fiber secondary wall deposition. These conclusions arose from： （a） analyzing the expression of CesA genes in arabidopsis shoot trichomes; （b） observing birefringent secondary walls in arabidopsis shoot trichomes with mutations in AtCesA4, 7, or 8; （c） assaying up-regulated genes during different stages of cotton fiber development; and （d） comparing genes that were co.expressed with primary or secondary wall CesAs in arabidopsis with genes up- regulated in arabidopsis trichomes, arabidopsis secondary xylem, or cotton fiber during primary or secondary wall deposition. Cumulatively, the data show that： （a） the xylem of arabidopsis provides the best model for secondary wall cellulose synthesis in cotton fiber; and （b） CesA genes within a ＂cell wall toolbox＂ are used in diverse ways for the construction of particular specialized cell walls.
文摘The Knoevenagel reaction of aromatic aldehydes with malononitrile and ethyl cyanoacetate proceeds smoothly in the presence of carboxymethyl cellulose supported triethylenetetramine as catalyst in the 95% ethanol to afford the desired E-isomers of the corresponding alkenes in yield of 74%～96% and good purity. The results confirm that the catalyst can offer definite advantages of good activity , easy separation, mild reaction condition and high yields. Moreover, it can be reused for not less than 5 runs.
