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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Inorganic Chemistry Research
- نوع مقاله: Journal Article
- کلمات کلیدی: Phosphine,Ullmann cross-coupling,Palladium catalyst,Hammett correlation,Mechanistic study
- چکیده:
- چکیده انگلیسی: Catalytic activity of a Pd/biphenyl based- phosphine system in the Ullmann cross-coupling reaction of various para-substituted aryl bromides were investigated. The results showed that the bulky electron-rich phosphine efficiently modify the electronic and steric properties of palladium center and promote the cross-coupling reaction. Mechanistic study using the Hammett correlation revels that electron-withdrawing substituents decrease the electron density at the palladium center and decrease the rate of oxidative-addition step such that this step will become the rate determining step (rds). On the other hand, electron-donating groups increase the rate of oxidative-addition step such that the reductive-elimination step will become the rds.
- انتشار مقاله: 19-04-1399
- نویسندگان: Sara Eavani,Ehsan Azadi,Mohammad Joshaghani
- مشاهده
- جایگاه : پژوهشی
- مجله: Inorganic Chemistry Research
- نوع مقاله: Journal Article
- کلمات کلیدی: Polyoxometalate,Oxidative desulfurization,Dibenzothiophene,Benzothiophene,thiophene
- چکیده:
- چکیده انگلیسی: Dibenzothiophene (DBT), benzothiophene (BT) and thiophene (T) were catalytically oxidized to their corresponding sulfone products by H2O2 in the presence of magnetically recoverable polyoxometalate-based nano catalyst. Different extracting solvents including ethanol, acetonitrile, and dimethylformamide were tested. The best results were obtained by ethanol extraction. The oxidative desulfurization (ODS) of model oils was investigated using different sulfur levels (100-1000 ppm). The removal of DBT could reach >99% and the sulfur content would be reduced from initial 100 to lower than 1 ppm, which can meet the standards of deep desulfurization. Two main aspects including the effects of nitrogen containing compounds and aromatic compounds on ODS of model oil were studied. Effect of indole, quinoline, toluene, xylene, mesitylene and naphthalene in ODS conversion were investigated. The catalyst could be easily separated from the reaction mixture using an external magnetic field, demonstrated an effective and simple separation method, and reused several times without significant change on ODS results.
- انتشار مقاله: 15-02-1399
- نویسندگان: Ezzat Rafiee,Sara Kazemi,Sara Eavani
- مشاهده
- جایگاه : پژوهشی
- مجله: Inorganic Chemistry Research
- نوع مقاله: Journal Article
- کلمات کلیدی: Phosphine,Ullmann cross-coupling,Palladium catalyst,Hammett correlation,Mechanistic study
- چکیده:
- چکیده انگلیسی: Catalytic activity of a Pd/biphenyl based- phosphine system in the Ullmann cross-coupling reaction of various para-substituted aryl bromides were investigated. The results showed that the bulky electron-rich phosphine efficiently modify the electronic and steric properties of palladium center and promote the cross-coupling reaction. Mechanistic study using the Hammett correlation revels that electron-withdrawing substituents decrease the electron density at the palladium center and decrease the rate of oxidative-addition step such that this step will become the rate determining step (rds). On the other hand, electron-donating groups increase the rate of oxidative-addition step such that the reductive-elimination step will become the rds.
- انتشار مقاله: 19-04-1399
- نویسندگان: Sara Eavani,Ehsan Azadi,Mohammad Joshaghani
- مشاهده
- جایگاه : پژوهشی
- مجله: Inorganic Chemistry Research
- نوع مقاله: Journal Article
- کلمات کلیدی: Polyoxometalate,Oxidative desulfurization,Dibenzothiophene,Benzothiophene,thiophene
- چکیده:
- چکیده انگلیسی: Dibenzothiophene (DBT), benzothiophene (BT) and thiophene (T) were catalytically oxidized to their corresponding sulfone products by H2O2 in the presence of magnetically recoverable polyoxometalate-based nano catalyst. Different extracting solvents including ethanol, acetonitrile, and dimethylformamide were tested. The best results were obtained by ethanol extraction. The oxidative desulfurization (ODS) of model oils was investigated using different sulfur levels (100-1000 ppm). The removal of DBT could reach >99% and the sulfur content would be reduced from initial 100 to lower than 1 ppm, which can meet the standards of deep desulfurization. Two main aspects including the effects of nitrogen containing compounds and aromatic compounds on ODS of model oil were studied. Effect of indole, quinoline, toluene, xylene, mesitylene and naphthalene in ODS conversion were investigated. The catalyst could be easily separated from the reaction mixture using an external magnetic field, demonstrated an effective and simple separation method, and reused several times without significant change on ODS results.
- انتشار مقاله: 15-02-1399
- نویسندگان: Ezzat Rafiee,Sara Kazemi,Sara Eavani
- مشاهده