Synthesis and Seperation of 1,1’-binaphthol
|School||Harbin Engineering University|
|Keywords||1，1’-bi-2-naphthols microwave synthesis carbamate derivatives separation|
In this paper, racemic binaphthol was synthsized by oxidative coupling of 2-naphthol in the presence of a catalytic amount of Cu(OH)2 or V2O5 and air by means of microwave irradiation technology. The effects of dosage of catalyst, reaction temperature, reaction time, and microwave power on the yields of binaphthol were investigated. The chemical structure and properties of BINOL were characterized by melting point tester, infrared spectroscopy (IR), nuclear magnetic resonance (NMR), time of flight mass spectrometry (TOF), and polarimeter. The optimized process conditions as follows:molar ratio of catalyst and 2-naphthol is 2 to 1, reaction temperature is 70℃, reaction time is 40 min, microwave power is 80 W. The yield of racemic binaphthol is 65.4%. In the presence of V2O5, reaction time needs 10 h with the yield of 61.5% by conventional heating way. However, it needs 5 h with the yield of 62.3% by microwave irradiation technology.Three different kinds of polysaccharide (cellulose, amylose and chitosan) were reacted with different isocyanates. Five cellulose carbamates derivatives including cellulose triphenyl carbamate, cellulose-tris(4-tertbutylphenyl carbamate), cellulose-tris(4-chlorophenyl carba-mate), cellulose-tris(3,5-dimethylphenyl carbamate) and cellulose-tris(3,5-dichlorophenyl carbamate, two amylose carbamates derivatives including amylose-tris(4-chlorophenyl carbamate) and amylose-tris(3,5-dichlorophenyl carbamate), and two chitosan carbamates derivatives including chitosan triphenyl carbamate, chitosan-tris(4-chlorophenyl carbamate) were synthesised. The structures of derivatives were measured by IR and 1H NMR. The synthesized derivatives were coated on 3-aminopropyl silica gel and then packed into HPLC columns to test their chiral recognition abilities. Of them, cellulose carbamates showed high chiral recognition abilities for binaphthol. Five kinds of cellulose carbamates showed chiral recognition abilities for binaphthol and the order of the chiral recognition ability from high to low is CSP-2> CSP-4> CSP-5> CSP-3> CSP-1. The binaphthol can not be resolved by means of amylose-and chitosan-based carbamates derivatives. The CSP based on chitosan triphenyl-carbamate seperated No.4 and No.9 racemate successfully but still failed to separate binaphthol.