Wang Guangle, Shang Zeren, Liu Mingdi, Dong Weibing, Li Haichao, Yin Haiqing, Gong Junbo, Wu Songgu
State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
School of Chemistry and Chemical Engineering, Qinghai Minzu University, Xining 810007, China.
Molecules. 2022 Jun 24;27(13):4085. doi: 10.3390/molecules27134085.
The metastable zone width (MSZW) of -methoxybenzoic acid (PMBA) in an ethanol-water system was measured using the polythermal method. The nucleation order obtained by the Nývlt's model indicates the nucleation of PMBA following a progressive nucleation mechanism at low saturation temperature ( = 3.18-7.50) and an instantaneous nucleation mechanism at high saturation temperature ( = 1.46-2.55). Then, combined with the metastable zone experiment and the Sangwal model, we found that the MSZW and the interfacial energy reached the maximum when the mass fraction of ethanol was 0.8, which resulted in the smallest crystal product size. Meanwhile, the maximum rcrit and ΔGcrit obtained based on the modified Sangwal model indicating the PMBA needs to overcome a higher nucleation barrier in the ethanol mass fraction of 0.8. Finally, we proposed a preferential strategy for adjusting MSZW by correlating the interfacial energy with the change in ethanol mass fraction, saturation temperature, and cooling rate, respectively.
采用变温法测定了对甲氧基苯甲酸（PMBA）在乙醇 - 水体系中的介稳区宽度（MSZW）。通过尼尔特模型得到的成核级数表明，在低饱和温度（(= 3.18 - 7.50)）下，PMBA的成核遵循渐进成核机制，而在高饱和温度（(= 1.46 - 2.55)）下遵循瞬时成核机制。然后，结合介稳区实验和桑瓦尔模型，我们发现当乙醇质量分数为0.8时，MSZW和界面能达到最大值，这导致晶体产物尺寸最小。同时，基于改进的桑瓦尔模型获得的最大(r_{crit})和(\Delta G_{crit})表明，PMBA在乙醇质量分数为0.8时需要克服更高的成核势垒。最后，我们分别通过将界面能与乙醇质量分数、饱和温度和冷却速率的变化相关联，提出了一种调节MSZW的优先策略。
