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本实验用分光光度法对麦迪霉素的稳定性进行研究。结果表明在55℃、70℃,于pH2～9范围内稳定,在50℃、55℃,65℃,pH=1.0,pH=12.0不稳定。其水解反应服从一级反应动力学公式,测得:pH=12.0:50℃,K=4.00×10~(-3)min~(-1),55℃,K=7.68×10~(-3)min~(-1),65℃,K=4.12×10~(-2)min~(-1);pH=1.0:50℃,K=1.76×10~(-3)min~(-1),55℃,K=6.41×10~(-3)min~(-1),65℃,K=2.14×10~(-2)min(-1)。并证明温度对反应速度的影响遵守阿累尼乌斯公式。求出pH=12.0,E_a=3.27×10~4cal/mol,A=3.98×10~(19);pH=1.0,E_a=3.43×10~4cal/mol,A=3.98×10~(20),并建立具体的阿累尼乌斯公式: pH=12.0:1gK=-7.1×10~3·_T~1+19.6 pH=1.0:1gK=-7.5×10~3·(1/T)+20.6
In this experiment, the stability of midecamycin was studied by spectrophotometry. The results are shown to be stable in the range of pH 2-9 at 55 ° C and 70 ° C and unstable at 50 ° C, 55 ° C, 65 ° C, pH = 1.0, pH = 12.0. The hydrolysis reaction obeyed the first-order reaction kinetics equation, and the results showed that the optimum reaction conditions were pH = 12.0:50 ℃, K = 4.00 × 10 -3 min -1, 55 ℃, K = 7.68 × 10 -3 (-1), K = 4.12 × 10 ~ (-2) min ~ (-1) at 65 ℃, K = 1.76 × 10 ~ (-3) min ~ (-1) ), 55 ℃, K = 6.41 × 10 -3 min -1, 65 ℃, K = 2.14 × 10 -2 min -1. And prove that the influence of temperature on the reaction rate obeys the Arrhenius formula. The results showed that pH = 12.0, E_a = 3.27 × 10 ~ 4cal / mol, A = 3.98 × 10 ~ 19, pH = 1.0, E_a = 3.43 × 10 ~ 4cal / mol, A = 3.98 × 10 ~ And establish the specific Arrhenius equation: pH = 12.0: 1gK = -7.1 × 10-3 · _T ~ 1 + 19.6 pH = 1.0: 1gK = -7.5 × 10-3 · (1 / T) +20.6