【摘要】 研究了松香中枞酸型树脂酸在惰性气体保护下,于180~270℃进行高温热处理1~4 h时的变化规律。结果表明,热作用时间低于3 h、温度低于240℃时,以长叶松酸、枞酸、新枞酸的相互热异构反应为主,长叶松酸、新枞酸向枞酸异构的速度和比例依松香种类不同略有差异。温度在240℃~260℃时,在热异构反应的同时伴有较多的脱氢反应,其脱氢速度顺序为思茅松松香>云南松松香>湿地松松香>马尾松松香。温度大于260℃时,去氢枞酸生成速度进一步加快,但同时树脂酸的脱羧等裂解反应也明显加快,使树脂酸总含量迅速下降。据此,在240~260℃下对松香进行高温热处理一定时间,可获得比原料松香颜色更浅的松香。更多还原

【Abstract】 The thermal reaction relationship of abietic-type acids in rosin is studied in detail through the treatment at 180-270℃ for 1-4 h in inert gases.As a result,the main reaction is the isomerization among palstric,abietic and neoabietic acids below 240℃ for less than 3 h,in which the rates are slightly different from rosin types.When treated at 240-260℃,the isomerization is accompanied with more dehydrogenation whose rate sequences are as such Simao pine rosin>Yunnan pine rosin>slash pine rosin>masson pine rosin.The dehydrogenation as well as decarboxylation goes faster over 260℃,therefore the total resin acid decreases quickly.According to the results,the lighter-colored rosin may be given out while a common rosin is treated in a temperature range of 240-260℃.更多还原