松香和酚醛树脂的紫外光谱特性及其反应过程跟踪

采用一阶导数紫外光谱法考察了松香、酚醛树脂、松香基酚醛树脂及其混合物的紫外光谱特征,建立了在无水乙醇中的定量分析方法,跟踪测定了松香与酚醛树脂反应过程的松香变化。结果表明,在257 nm处,松香的吸光度对波长的一阶导数绝对值较大,而酚醛树脂和松香基酚醛树脂为0,利用建立松香物质的量浓度与吸光度一阶导数的定量分析方法跟踪反应过程,能消除酚醛树脂和松香基酚醛树脂的影响。松香吸光度一阶导数绝对值Y与物质的量浓度C定量分析方程为Y=0.009 2C+0.000 90(C的取值为0.50×10-5⁵.0×10-5mol/L),方法的回收率为97.05%5.0×10-5mol/L),方法的回收率为97.05%¹01.33%,精密度、稳定性和回收率的RSD分别为3.37%,2.60%和2.36%。采用该方法测定反应过程,发现反应2 h后松香和酚醛树脂基本完成,与实际工艺设定的反应终点时间一致。

The ultraviolet spectrum characteristics of rosin and phenolic resin and the reaction process tracking

Using the first derivative UV spectrophotometry for detecting the absorption characteristic of rosin, phenolic resin, rosin phenolic resin and their mixture, the quantitative analysis methods were estab lished in the ethanol, and traced rosin and phenolic resin reaction process changes. Results showed that the rosin of first derivative absolute value of absorbance and wavelength is larger at 257 nm, but the first derivative value of phenolic resin and rosin phenolic resin is zero. Using the quantitative analysis method of rosin molarity and absorbance of first derivative to track reaction process can eliminate the effect of phenolic resin and rosin phenolic resin. The quantitative analysis equation of rosin absorbance of first de- rivative absolute value Y and molarity C： Y = 0. 039 2C ＋ 0. 000 90（ C = 0.50 x 10-5 - 5.0 x 10 -5 tooL/L）. The recovery rate of the range is 97.05% - 101.33% , the relative standard deviations of precision, stability and recovery rate were 3.37% ,2.60% and 2.36%. Using the method found that the reaction of rosin and phenolic resin was basically completed in 2 h, and this coincide with the reaction end point of actual process.