Synthesis Of Polyether Modified Quaternary Ammoniums And Their Application On Hydroformylation Of Higher Olefins In Aqueous/Organic Biphasic System

Higher aldehydes/alcohols (C8-C18) from the hydroformylation of higher olefins are important raw materials in the production of plasticizers, surfactants and detergents. The water/organic biphasic system with catalysts of water-soluble organic metal complexes not only keeps the advantages of high activity and selectivity and mild reaction conditions in homogeneous catalysis, but also solves the long-standing difficulty in the seperation of catalysts and products in homogeneous catalysis. However, the hydroformylation reaction rate is greatly reduced by very low solubility of higher olefins in water, when the water/organic biphasic system is applied on the hydroformylation of higher olefins. Therefore, only through improving the properties of water/organic biphase and increasing the contact chance of olefins and water-soluble catalysts, the reaction rate on the hydroformylation of higher olefins in water/organic biphasic system can be enhanced.Based on the principle of cationic surfactants micelle catalysis and the feature of non-ionic surfactants cloud point, two kinds of polyether modified quaternary ammoniums (as shown in Figure A and B) were synthesized, of which the structure have been characterized through 1H-NMR technique.These two kinds of polyether modified quaternary ammoniums have been applied on hydroformylation of higher olefins catalyzed by water-soluble rhodium-phosphine complexes in aqueous/organic biphasic system. The effects of reaction temperature, pressure and molar ratio of ligand to rhodium have been investigated. Under the optimized reaction conditions (A: n(Rh)=2.5×10-3 mmol, n(A)=6×10-3 mmol, TPPTS/Rh=15, S/Rh=2000, T=110℃, P=5 MPa, t=4 h; B:n(Rh)=2.5×10-3 mmol, n(B)=6×10-3 mmol, TPPTS/Rh-15, S/Rh=2000, T=110℃, P=6 MPa, t=5 h), the conversion of 1-dodecene and the selectivity of aldehyde reached up to 90%. The catalysts can be recycled well for five times. The results show that the polyether modified quaternary ammoniums A and B can greatly improve the reaction rate of 1-dodecene hydroformylation catalyzed by rhodium/TPPTS (tris (3-sulfonatophenyl) phosphine, sodium salt) complexes in aqueous/organic biphasic system.