采用超声波强化反应-结晶耦合的方法单离松香主要成分枞酸,测定了枞酸的恒容燃烧热、熔点和比旋光度,通过UV、GC-MS、NMR对枞酸进行分析鉴定。结果表明,用GR-3500B2氧弹式量热计测定枞酸的恒容燃烧热为–11441.46 kJ mol 1,计算出枞酸的标准摩尔燃烧焓和标准摩尔生成焓分别为–11457.57 kJ mol 1和–699.43 kJ mol 1;用341LC plus微量旋光仪测定枞酸的比旋光度为–105.4;用DSC 6200差示扫描量热仪测得枞酸的熔点和熔化焓分别为450.89 K和19.44 kJ mol 1,计算出枞酸的熔化熵为43.11 J mol 1 K 1。
Abietic acid, a major component of rosin, was isolated by means of reaction-crystallization strengthened with ultrasonic waves, and then it was characterized by ultraviolet visible spectra (UV), gas chromatography-mass spectra (GC-MS), and 1H nuclear magnetic resonance spectra (1H-NMR), respectively. The constant-volume combustion heat of abietic acid was determined to be -11441.46 kJ.mol^-1 by GR-3500B2-type oxygen bomb calorimeter, and based on the thermodynamic principle, the standard molar combustion enthalpy and molar enthalpy of formation of abietic acid were calculated to be -11457.57 kJ-mol^-1 and -699.43 kJ-mol^-1. The specific optical rotation of the abietic acid was determined to be -105.4° by using a 341LC polarimeter. The melting point and the molar fusion enthalpy of abietic acid were determined to be 450.89 K and 19.44 kJ.mol^-1 via differential scanning calorimetry (DSC), and the molar fusion entropy of abietic acid was calculated to be 43.11 J.mol^-1.K^-1 according to thermodynamic principle.