有机化合物波谱解析课件 红外结合质谱综合习题及答案.pdfVIP

     IRMS problems  1. A pleasant smelling liquid having a boiling point of 101℃. Major Infrared Absorptions Major Ions in the Mass Spectrum -1 2880 to 2980 cm 29 1737(str) 41 1194(str) 56 1166(str) 73   1 / 5         Answer The infrared spectrum suggests an ester. Carbonyl stretching at 1737 and C-O stretching at Lack of C-H absorption above 3000 indicates no unsaturation. The molecular ion has an even mass, and most fragment ions have odd ℃masses. The base peak at m/z=57 suggests a tert-butyl group. The M-15 ion is quite weak, and the 85 ion is due to loss of methoxide. The compound is methyl 2, 2-dimethylpropanoate. 2 An oily liquid having a boiling point of 191 ℃ and a melting point of -13 ℃ Major Infrared Absorptions Major Ions in the Mass Spectrum -1 3066cm 50(small) 2230(str) 76 1599 103 base ion and molecular ion 1492 104 is ca.8% of base 1448 758 688