两相催化体系中双子表面活性剂对1-十二烯氢甲酰化反应的助催化作用

合成了几种具有刚性连接基团的双子表面活性剂,研究了它们在Rh-TPPTS体系中催化长链烯烃氢甲酰化反应中的助催化作用.结果表明,在水/有机两相催化体系中,新型双子表面活性剂的助催化作用比单链表面活性剂CTAB更好,在较低的表面活性剂浓度下能得到较高的反应转化率.这归因于此类表面活性剂有较低的cmc,降低界面张力的能力和对1-十二烯的增溶能力比CTAB更强.

Promotion Effect of Cationic Gemini Surfactants on 1-Dodecene Hydroformylation in Biphasic Catalytic System

New cationic gemini surfactants with a rigid spacer group of xylene were synthesized, their compositions and structures were characterized. The cmc and the solubilizations of 1-dodecene in micellar solution were determined by surface tension method and UV-Vis spectrometry respectively. The cmc of new gemini surfactants are lower than CTAB by about an order, but the solubilizations of 1-dodecene in gemini surfactants solution are higher than that in CTAB solution. The promotion effect of cationic gemini surfactants on 1-dodecene hydroformylation in biphasic catalytic system was studied. The results indicated that in the biphasic system containing the catalysts RhCl(CO)(TPPTS)2 and TPPTS, TPPTS=tris(sodium-m-sulfonatophenyl) phosphine], the reaction rate of 1-dodecene hydroformylation in the presence of gemini surfactants was faster than that in the presence of conventional surfactant CATB, e.g., the conversion of 1-dodecene is 90% when G(o-xyl) C22 concentration in aqueous solution was 2×10-3 mol/L, however, the conversion was only 20.4% when the concentration of CTAB was 3×10-3 mol/L. The greater acceleration of gemini surfactants in 1-dodecene hydroformylation could be attributed to that cationic gemini surfactants had lower cmc and better solubilization for the substrate. The lower cmc and surface tension are favorable for increasing the interfacial area of two phases, breaking phase barrier and promoting the substrate transfer to interface where the substrates coordinate with the active rhodium complex anion species. The regioselectivity for olefin hydroformylation in gemini surfactants.