The complex of Bis(2,4 pentanedionato) Cobalt has been synthesized.The structure has been characterized by infrared spectra and element analysis.The catalytic activity of the complex in the cyclohexene allylic oxidati...The complex of Bis(2,4 pentanedionato) Cobalt has been synthesized.The structure has been characterized by infrared spectra and element analysis.The catalytic activity of the complex in the cyclohexene allylic oxidation by oxygen molecule has been studied.The influences of reaction temperature,time,solvents and additives on the oxidation have been determined.The results show that when the oxidation is carried out under the reaction conditions of 70～80℃,4～10h and 2.0Mpa/O 2,the main product is cyclohexene 2 one.The conversion of cyclohexene increases with the rise of the reaction temperature,time and polarity of solvent.Some additives,such as imidazole,could improve the selectivity of cyclohexene 2 one.展开更多
The effects of different surfactants (cationic, anionic and nonionic) on 1 dodecene hydroformylation catalyzed by water soluble rhodium TPPTS [P( m C 6H 4SO 3Na) 3] complex in two phase catalytic system were studied. ...The effects of different surfactants (cationic, anionic and nonionic) on 1 dodecene hydroformylation catalyzed by water soluble rhodium TPPTS [P( m C 6H 4SO 3Na) 3] complex in two phase catalytic system were studied. The results showed that the cationic surfactant efficiently increased the reaction rate, owing to the solubilization of olefin in micelle and owing to the electrostatic interaction between the positive micelle and the negative catalytic active intermediates, HRh(CO) x [P( m C 6H 4SO 3) 3] n 3n- , which favored the coordination with olefin. The nonionic surfactant, which has only the solubilization for olefin, just increased slightly the rate. However, the anionic surfactant inhibited the reaction owing to the electrostatic repulsion between the negative micelle and the catalytic active intermediates. When the benzene sulfonated salt substituted by hydrophobic group was added, the molar ratio of normal aldehyde to iso aldehyde increased dramatically from 6 5 to 22 3 for 1 dodecene hydroformylation in the presence of cetyltrimethylammonium bromide (CTAB). This may be attributed to the formation of tighter micelle caused by the insertion of the substituted benzene sulfonate into the palisade layer, which favored the formation of normal aldehyde with lower steric hindrance. The fact that the addition of substituted benzene sulfonate could not improve the regioselectivity for normal aldehyde in the presence of benzyltetradecyldimethylammoniun chloride (BDAC) supported the above hypothesis, because BDAC has larger cationic head and favors the formation of iso aldehyde than CTAB, therefore, the combination of the proper additives could attain highly regioselective hydroformylation in two phase catalytic system.展开更多
文摘The complex of Bis(2,4 pentanedionato) Cobalt has been synthesized.The structure has been characterized by infrared spectra and element analysis.The catalytic activity of the complex in the cyclohexene allylic oxidation by oxygen molecule has been studied.The influences of reaction temperature,time,solvents and additives on the oxidation have been determined.The results show that when the oxidation is carried out under the reaction conditions of 70～80℃,4～10h and 2.0Mpa/O 2,the main product is cyclohexene 2 one.The conversion of cyclohexene increases with the rise of the reaction temperature,time and polarity of solvent.Some additives,such as imidazole,could improve the selectivity of cyclohexene 2 one.
文摘The effects of different surfactants (cationic, anionic and nonionic) on 1 dodecene hydroformylation catalyzed by water soluble rhodium TPPTS [P( m C 6H 4SO 3Na) 3] complex in two phase catalytic system were studied. The results showed that the cationic surfactant efficiently increased the reaction rate, owing to the solubilization of olefin in micelle and owing to the electrostatic interaction between the positive micelle and the negative catalytic active intermediates, HRh(CO) x [P( m C 6H 4SO 3) 3] n 3n- , which favored the coordination with olefin. The nonionic surfactant, which has only the solubilization for olefin, just increased slightly the rate. However, the anionic surfactant inhibited the reaction owing to the electrostatic repulsion between the negative micelle and the catalytic active intermediates. When the benzene sulfonated salt substituted by hydrophobic group was added, the molar ratio of normal aldehyde to iso aldehyde increased dramatically from 6 5 to 22 3 for 1 dodecene hydroformylation in the presence of cetyltrimethylammonium bromide (CTAB). This may be attributed to the formation of tighter micelle caused by the insertion of the substituted benzene sulfonate into the palisade layer, which favored the formation of normal aldehyde with lower steric hindrance. The fact that the addition of substituted benzene sulfonate could not improve the regioselectivity for normal aldehyde in the presence of benzyltetradecyldimethylammoniun chloride (BDAC) supported the above hypothesis, because BDAC has larger cationic head and favors the formation of iso aldehyde than CTAB, therefore, the combination of the proper additives could attain highly regioselective hydroformylation in two phase catalytic system.
