OTPPTS对烯烃氢甲酰化反应的影响

 研究了水/有机两相体系中TPPTS(磺化三苯基膦)氧化为OTPPTS(氧化的TPPTS)对Rh/TPPTS催化烯烃氢甲酰化反应的影响. 结果表明,在己烯-1、辛烯-1和十二烯-1氢甲酰化反应中,当n(OTPPTS)/n(TPPTS)＜1时,对催化剂体系性能的影响较小,但当n(OTPPTS)/n(TPPTS)＞1时,将引起催化剂体系的活性、选择性和稳定性下降; 如果保持体系中TPPTS的含量一定,使n(TPPTS)/n(Rh)≥18,当n(OTPPTS)/n(Rh)＝20时,则对催化剂体系性能的影响不明显. 这说明生成的OTPPTS不是铑催化剂的毒物. TPPTS氧化为OTPPTS致使铑催化剂的活性和生成醛的选择性下降, 是由于TPPTS浓度的降低导致n(TPPTS)/n(Rh)值过低,使催化循环中各活性物种的平衡发生变化及铑配合物的稳定性变差所造成的结果.

Influence of OTPPTS on Olefin Hydroformylation in Biphase Catalytic System

The hydroformylation of hexene-1, octene-1 and dodecene-1 catalyzed by water/soluble rhodium complex [RhCl(CO)(TPPTS) 2](TPPTSP(m-C 6H 4SO 3Na) 3) in the presence of OTPPTS (oxidized TPPTS) and cationic surfactant CTAB (cetyltrimethyl ammonium bromide) was studied. The results indicated that when TPPTS was oxidized to OTPPTS, the catalyst activity and selectivity for aldehyde decreased because the TPPTS content in aqueous solution decreased and thereby the TPPTS/Rh ratio was too low. If the TPPTS/Rh molar ratio was kept being a constant and larger than 18, moreover n(OTPPTS)/ n(TPPTS)<1, the catalytic performance of rhodium complex did not obviously change with the increase of n(OTPPTS)/ n(Rh). It was confirmed that although OTPPTS was not a poison for the rhodium catalyst, the increase of OTPPTS in the aqueous solution made the total phosphine concentration increase, which caused the rhodium complex to become more stable, thus the catalyst activity decreased. When the TPPTS/Rh ratio was larger, for example n(TPPTS)/ n(Rh)=30, and the molar ratio of total phosphine (TPPTS+OTPPTS) to Rh was higher than 60, the selectivity for aldehyde increased to about 98%, the content of dodecane and dodecene-2 in the products decreased to about 1 5% and zero, respectively.