【作者】 钟华；

【导师】 陈小鹏；

【作者基本信息】 广西大学 ， 化学工艺， 2008， 硕士

【摘要】 脱氢枞酸是歧化松香的主要化学成分,是一种重要的精细化工原料,在医药、农药、表面活性剂和在精细有机合成中间体等众多领域存在广泛应用。虽然脱氢枞酸用途广泛,但脱氢枞酸是以混合物的形式存在于歧化松香中,并且难以分离出高纯度脱氢枞酸,因此脱氢枞酸的热力学性质数据十分匮乏。因此,研究脱氢枞酸的基础热力学数据及其分子几何结构可为进一步开发与利用松香可再生资源提供理论基础。本文包含如下内容:采用逐级酸化沉淀法制备出高纯度的脱氢枞酸,用红外光谱IR以及紫外光谱对脱氢枞酸进行结构鉴定,证实所得产品为脱氢枞酸;由气相色谱GC进行定量分析,测出脱氢枞酸含量为99.99%;脱氢枞酸溶解于无水乙醇中的溶液的紫外光谱的吸收波长λ_max分别为268nm,276nm,与文献值相符。采用WRS-1B数字熔点仪测定脱氢枞酸的熔点为171.6℃;由PerkinElmer公司的Pyris DSC-7差示扫描量热分析仪测定脱氢枞酸的熔点以及熔化焓分别为171.4℃和△_mH=-19.74kJ/mol;采用氧弹燃烧量热仪测定脱氢枞酸的标准摩尔燃烧焓△_cH⁰_m=11234.85kJ/mol,通过计算得到脱氢枞酸的标准摩尔生成焓△_fH⁰_m=-636.38kJ/mol。采用Pyris Diamond TG/DTA综合热分析仪器测定了脱氢枞酸在静态空气气氛下不同升温速率的热重（TG）曲线,研究了脱氢枞酸的在静态空气气氛的热分解反应,获得了脱氢枞酸在静态空气气氛下热分解反应动力学三参数:活化能E=106.92kJ/mol,指前因子A=7.60×10⁸/s,机理函数G（α）=3（1-α）^2/3。采用MINDO/3、MNDO、PM3三种半经验分子轨道方法对枞酸分子结构进行优化计算,并通过与枞酸分子结构的文献值进行比较发现,PM3方法比MINDO/3、MNDO较适宜,是研究枞酸类分子比较好的半经验分子轨道方法。此基础上,采用PM3方法对脱氢枞酸结构进行研究,计算优化了脱氢枞酸的结构。优化结果表明,脱氢枞酸分子中A环为椅式结构,B环为半椅式结构,C环为平面结构;构成脱氢枞酸苯环的C8,C9,C11,C12,C13,C14基本处于同一平面,在这个苯环上的相关原子C7,C10,C15与苯环也是同处于一个平面;C5上的H与C10上的甲基CH₃处于反式连接状态。更多还原

【Abstract】 Dehyroabietic acid is a very important fine chemical raw materials and it has a prosperous future in the field of medicine,pesticide,surfactant and fine organic synthesis and so on.Dehyroabietic acid have wide range application in many area,but it is hard to separate from disproportionated rosin.Therefore,the study of basal technical data and the geometry of the dehyroabietic acid is very insistent and necessity.On the basis of a lot of experiments, many basal technical data for dehyroabietic acid is obtain by experiment.The geometry of the dehyroabietic acid is study by the quantum chemistry methods.This paper covers the contents as follows:High purity dehydroabietic acid was prepared from disproportionated rosin by means of fractional acidification.Quantitative and qualitative analyses of the product by the IR and UV,the purity of the dehydroabietic acid is 99.99%determinated by means of GC.To get the chemical thermodynamic data,firstly,the melting point of the dehyroabietic acid were determinated to be 171.6℃,171.39℃by the digital melting point instructor and DSC.The melting enthalpy of dehyroabietic acid was determinated to be△_mH=-19.74kJ/mol by the DSC techniques.Second,the standard combustion enthalpy was measured to be△_cH⁰_m=-11234.85kJ/mol by means of Oxygen Bomb Calorimeter.The standard formation enthalpy was calculated to be△_fH⁰_m=-636.38kJ/mol.The non-isothermal decomposition kinetics of dehydroabietic acid in Ar was investigated by TG-DTG techniques with various heating rates of 5℃/min,15℃/min and 20℃/min.The non-isothermal kinetics parameters were analyzed by means of Achar-Brindley-Sharp and Satava-Setak respectively,and the thermal decomposition mechanism of dehydroabietic acid was also studied with the Satava-Sestak method.The results show that the thermal decomposition mechanism of dehydroabietic acid was controlled by random nuclear producing and growing process,the apparent activation energy and pre-exponential factor are E=106.92kJ/mol and lnA=20.45s^-1,respectively,the reaction order is n=2/3,and the kinetic equation can be expressed as,G（α）= 3（1-α）^2/3.The optimization of geometrical structure of abietic acid was carried out by three semi-emperical molecular orbital methods of MINDO/3,MNDO,PM3.It is showned that the PM3 methods is better than the MINDO/3 and the MNDO methods for geometrical structure of rosin acids.Therefore,the geometrical structure of dehydroabietic acid is optium by PM3 methods.The optimization of geometrical structure of dehydroabietic acid as fellows:the A ring of geometrical structure of dehydroabietic acid is chair conformation;the B ring of geometrical structure of dehydroabietic acid is half-chair confomation;the C ring of geometrical structure of dehydroabietic acid is plane conformation.The benzene C8-C14 of dehyroabietic acid is in the same plane.Otherwise,the C7,C10,C15 is also in the same plane with the benzene group of dehyroabietic acid.更多还原