Cellulose Acetate Derivatives As Chiral Separation Membrane Material Of Research And Application

Membrane separation technology is an energy saving and environmental protection method,which is high-performance and easy to be industrialization.It has been widely used in sewage treatment and desalination of sea water and many other fields,and has achieved good economic and social benefits.This thesis is focused on membrane separation technology for the enantioseparation.It summarizes the practical significance of chiral separation,common types of membranes,the applications of cellulose derivatives in chiral separation,and the sorts of enantioselective membranes.Coating cellulose acetate on silanized silica gel,the chiral stationary phase(CSP) was prepared and the empty column of HPLC was packed.With hexane-isopropanol as mobile phase,the enantioseparation of twenty racemates on the column was studied.The enantioselective membrane were prepared using cellulose acetate(M= 100000) as the membrane material.The flux and permselective properties of membrane with trans-stilbene oxide and(R,S)-2-phenyl-l-propanol as feed solution were investigated.The properties of the membrane can be influenced by changing the cellulose acetate and DMF concentration in casting solution,coagulation bath temperature,operating pressure,and feed concentration,respectively.The optical resolution of over 90%enantiomeric excess to trans-stilbene oxide and(R, S)-2-phenyl-1-propanol could be achieved.Cellulose triacetate(M=200000) was used as the membrane material to prepare the optical resolution membrane,it can separate(R,S)-2-phenyl-1-propanol and trans-stilbene oxide too,the resolution of over 80%enantiomeric excess can be obtained.