从系统工程视角试论基于基团贡献法的树脂基体的分子设计

从系统工程的观点,提出了基于基团贡献法的树脂基体的计算机辅助分子设计的框架轮廓,以图促进潜在地作为传统树脂基体研发方法的有效替代或者至少是有益的补充的树脂基体的计算机辅助分子设计方法的发展。     

萃取溶剂分子设计的官能团预选

提出一种萃取溶剂分子设计中预选官能团的新方法,可以有效地缩小分子设计问题的规模。这种方法首先将分子体系中分子相互作用能的概念推广到官能团溶液,再联系UNIFAC法的相互作用参数,得到官能团预选的分子判据;然后结合Gan i的官能团预选经验规则,最终使萃取溶剂分子设计的官能团预选问题得到较好的解决。     

结合图论和基团贡献法的非均相共沸精馏挟带剂设计

非均相共沸精馏挟带剂的计算机辅助分子设计(CAMD)由分子合成、分子筛选及分子确认3个环节递进构成。在分子合成环节,预选基团,限定合成分子的基团总数及类型,基于图论原理实现由基团到分子的自动合成。在分子筛选环节,依据基础物性筛选指标形成基础分子库,输入待分离物系,采用非均相共沸物形成判据筛选出若干候选分子。在分子确认环节,由非均相共沸温度及组成、挟带剂的汽化热等参数组成模糊综合评判函数,实现分子排序,从而输出一组较优挟带剂。以乙酸-水物系、乙腈-乙酸乙酯物系为例,得到了相应设计结果,与文献结果进行了对比。研究表明该方法及所编程序具备可靠实用性,可为近沸程及共沸混合物分离过程的开发与设计提供先导性支持。     

Hydrocracking of polycyclic aromatic compounds using zeolite catalysts: Explanation of product distribution based on a computer aided molecular design study on the interaction of zeolite and substrates

Hydrocracking of phenanthrene was conducted in a batch autoclave system using ZSM-5 (5.5 Å), mordenite (7 Å) and Y-type zeolite (8 Å) as catalysts. The number in brackets is the size of the pore of each zeolite. Close examination of product distribution derived from hydrocracking of phenanthrene indicated that it is strongly affected by the pore size of the zeolite used. Based on the computer aided molecular design studies of each zeolite, the way of aromatic compounds accessing towards the entrance of the pore of zeolite was visualized, herewith being able to explain the characteristic distribution of the products.     

基于高阶基团贡献法与COSMO-SAC模型的溶剂设计方法

提出了一种基于高阶基团贡献法与类导体屏蔽片段活度系数模型（conductor like screening model-segment activity coefficient, COSMO-SAC）的计算机辅助溶剂设计方法（computer-aided molecular design, CAMD）。首先,基于高阶基团贡献法（higher-order group contribution, GC⁺）与COSMO-SAC模型构建GC⁺-COSMO方法,关联分子基团组合与表面屏蔽电荷密度分布[σ-profiles, p(σ)]、分子空腔体积V_c,实现对二者的高通量预测;然后结合基于简化分子线性输入系统（simplified molecular input line entry system, SMILES）的异构体生成算法与GC⁺-COSMO方法实现CAMD技术对异构体的识别及性质区分;最后,通过目标函数与约束方程组成的混合整数非线性规划模型（mixed integer nonlinear programming, MINLP）来建立溶剂设计问题,进一步采用分解式算法优化求解,实现溶剂优化设计目标。基于以上模型和方法开展了狄尔斯-阿尔德（Diels-Alder, DA）竞争性反应溶剂设计,验证了提出的方法的可行性与有效性。     

A theoretical study of solvent effects on Kolbe-Schmitt reaction kinetics

A theoretical DFT study was employed to confirm the Kolbe-Schmitt reaction mechanism and investigate solvent effects on this reaction. The use of a solvent in the Kolbe-Schmitt reaction is desirable to facilitate a homogeneous reaction mixture and potentially improve the reaction rate. The candidate solvents were designed using computer aided molecular design (CAMD) and tested using DFT solvation calculations. The results from the quantum mechanical calculations were then used to determine the rate constants for each elementary step, the overall reaction yields and the corresponding residence time. The methodology was tested on the reaction without solvent, with solvents reported in the literature, and with the designed solvents. The study revealed that in the presence of solvents with high dielectric constant the reaction becomes reversible, leading to low product yields.     

An improved control vector iteration approach for nonlinear dynamic optimization. II. Problems with path constraints简

This paper considers dealing with path constraints in the framework of the improved control vector iteration （CVI） approach. Two available ways for enforcing equality path constraints are presented, which can be directly incorporated into the improved CVI approach. Inequality path constraints are much more difficult to deal with, even for small scale problems, because the time intervals where the inequality path constraints are active are unknown in advance. To overcome the challenge, the ll penalty function and a novel smoothing technique are in-troduced, leading to a new effective approach. Moreover, on the basis of the relevant theorems, a numerical algo-rithm is proposed for nonlinear dynamic optimization problems with inequality path constraints. Results obtained from the classic batch reaCtor operation problem are in agreement with the literature reoorts, and the comoutational efficiency is also high.     

Optimization‐based framework for computer‐aided molecular design

A new framework to automate, augment, and accelerate steps in computer‐aided molecular design is presented. The problem is tackled in three stages: (1) composition design, (2) structure determination, and (3) extended design. Composition identification and structure determination are decoupled to achieve computational efficiency. Using approximate group‐contribution methods in the first stage, molecular compositions that fit design targets are identified. In the second stage, isomer structures of solution compositions are determined systematically, and structure‐based property corrections are used to refine the solution pool. In the final stage, the design is extended beyond the scope of group‐contribution methods by using problem‐specific property models. At each design stage, novel optimization models and graph theoretic algorithms generate a large and diverse pool of candidates using an assortment of property models. The wide applicability and computational efficiency of the proposed methodology are illustrated through three case studies. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3686–3701, 2013     

分离过程第3组分分子设计的一种新策略

提出一种新的基于基团贡献法设计并筛选选择性分离第 3组分的计算机辅助分子设计策略 ,推出由预选基团构成目标分子时必须遵循的组合方式表 ,对Gani等首创的同类设计方法做了补充和改进 ,并编制了相应的设计软件。应用本设计方法和设计软件 ,能从预选基团出发设计得到所有组合可能的目标分子 .列举了几个设计实例 .     

智能约束处理技术综述

首先时函数约束优化问题进行数学描述,分析其求解难点,然后综述当今主流的一些智能约束处理技术.包括罚函数法、基于排序的方法、基于可行性规则的方法、基于多目标的方法、特殊算子、基于译码器的方法、基于文化算法的技术、修补技术以及混合策略等,最后提出了有待进一步研究的几个方面.     

COSMO‐based computer‐aided molecular/mixture design: A focus on reaction solvents

In this article, we investigate reaction solvent design using COSMO‐RS thermodynamics in conjunction with computer‐aided molecular design (CAMD) techniques. CAMD using COSMO‐RS has the distinct advantage of being a method based in quantum chemistry, which allows for the incorporation of quantum‐level information about transition states, reactive intermediates, and other important species directly into CAMD problems. This work encompasses three main additions to our previous framework for solvent design (Austin et al., Chem Eng Sci. 2017;159:93–105): (1) altering the group contribution method to estimate hydrogen‐bonding and non‐hydrogen‐bonding σ‐profiles; (2) ab initio modeling of strong solute/solvent interactions such as H‐bonding or coordinate bonding; and (3) solving mixture design problems limited to common laboratory and industrial solvents. We apply this methodology to three diverse case studies: accelerating the reaction rate of a Menschutkin reaction, controlling the chemoselectivity of a lithiation reaction, and controlling the chemoselectivity of a nucleophilic aromatic substitution reaction. We report improved solvents/mixtures in all cases. © 2017 American Institute of Chemical Engineers AIChE J, 63: 104–122, 2018     

A hierarchical method to integrated solvent and process design of physical CO2 absorption using the SAFT‐γ Mie approach

Molecular‐level decisions are increasingly recognized as an integral part of process design. Finding the optimal process performance requires the integrated optimization of process and solvent chemical structure, leading to a challenging mixed‐integer nonlinear programming (MINLP) problem. The formulation of such problems when using a group contribution version of the statistical associating fluid theory, SAFT‐γ Mie, to predict the physical properties of the relevant mixtures reliably over process conditions is presented. To solve the challenging MINLP, a novel hierarchical methodology for integrated process and solvent design (hierarchical optimization) is presented. Reduced models of the process units are developed and used to generate a set of initial guesses for the MINLP solution. The methodology is applied to the design of a physical absorption process to separate carbon dioxide from methane, using a broad selection of ethers as the molecular design space. The solvents with best process performance are found to be poly(oxymethylene)dimethylethers. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3249–3269, 2015