A reaction density functional theory study of solvent effect in the nucleophilic addition reactions in aqueous solution

Whereas the proper choice of reaction solvent constitutes the cornerstone of the green solvent concept,solvent effects on chemical reactions are not mechanistically well understood due to the lack of feasible molecular models.Herein,by taking the case study of nucleophilic addition reaction in aqueous solution,we extend the proposed multiscale reaction density functional theory(RxDFT)method to investigate the intrinsic free energy profile and total free energy profile,and study the solvent effect on the activation and reaction free energy for the nucleophilic addition reactions of hydroxide anion with methanal and carbon dioxide in aqueous solution.The predictions of the free energy profile in aqueous solution for these two nucleophilic addition reactions from RxDFT have a satisfactory agreement with the results from the RISM and MD-FEP simulation.Meanwhile,the solvent effect is successfully addressed by examining the difference of the free energy profile between the gas phase and aqueous phase.In addition,we investigate the solvent effect on the reactions occurred near solid-liquid interfaces.It is shown that the activation free energy is significantly depressed when reaction takes place in the region within 10A distance to the substrate surface owing to the decrease of hydration free energy at the solid-liquid interface.

运动颗粒对传质过程影响的格子Boltzmann模拟

颗粒的主动运动对传质过程有重要影响。以表面恒浓度的二维球形颗粒为研究对象,采用耦合传质的格子Boltzmann方法(LBM)模拟了颗粒在自旋和振动两种情况下的相间传质过程。选择浸入运动边界法和非平衡态外推法处理运动颗粒边界,研究了颗粒自旋速度、颗粒振幅及振动频率对传质过程的影响。结果表明,中等雷诺数的自旋颗粒绕流中,随着颗粒自旋转速增大,颗粒的传质舍尔伍德数反而降低,表明在强制对流的情况下,颗粒自旋减弱颗粒的传质效果。当颗粒振动时,颗粒振幅越大,传质舍尔伍德数增大;当颗粒振动频率造成锁定现象时,颗粒流体相间传质效果显著增强。本工作的数值结果不仅表明格子Boltzmann方法可以有效模拟强制对流传质的过程,也为强化传质提供了一种思路。