Summary: TBOT is a proven catalyst for the esterification step of the PPT polymerization process. Previous studies have shown that the performance of TBOT is superior in terms of the enhanced degree of polymerization and shorter processing time. However, one interesting aspect which has not yet been investigated is whether with different process objectives, like by‐product minimization and controlled growth of desired functional groups, any other catalyst offers any increase in process performance. The present study gives a detailed process analysis through different sets of optimized operations, which consists basically of searching for other catalytic options for process improvements. A well validated kinetic model for the esterification step of the PPT polymerization process and the advanced Real‐Coded NSGA‐II optimization routine have been used in this study. It can be seen that with all the process considerations, such as maximization of the degree of polymerization, minimization of processing time and the enhanced controlled growth of desired functional groups and minimization of by‐products, the Zn‐based catalyst can replace the conventional Ti‐based catalyst. An Sn‐based catalyst was also found to be able to compete with these two catalysts in some cases.
Optimized Pareto plot for a study on the 4 objectives case for various catalysts. The Zn‐based catalyst outperforms the others. 相似文献
The M/G/1 queue with impatient customers is studied. The complete formula of the limiting distribution of the virtual waiting time is derived explicitly. The expected busy period of the queue is also obtained by using a martingale argument. 相似文献
In this study, we investigated how the presence of multiple intermolecular interaction sites influences the heteromeric supramolecular assembly of N-[(3-pyridinylamino) thioxomethyl] carbamates with fluoroiodobenzenes. Three targets—R-N-[(3-pyridinylamino) thioxomethyl] carbamate (R = methyl, ethyl, and isobutyl)—were selected and crystallized, resulting in three parent structures, five co-crystals, and one co-crystal solvate. Three hydrogen-bonded parent crystal structures were stabilized by N-H···N hydrogen bonding and assembled into layers that stacked on top of one another. Molecular electrostatic potential surfaces were employed to rank binding sites (Npyr > C=S > C=O) in order to predict the dominant interactions. The N-H⋯H hydrogen bond was replaced by I⋯Npyr in 3/6 cases, I⋯C=S in 4/6 cases, and I⋯O=C in 1 case. Interestingly, the I⋯C=S halogen bond coexisted twice with I⋯Npyr and I⋯O=C. Overall, the MEPs were fairly reliable for predicting co-crystallization outcomes; however, it is crucial to also consider factors such as molecular flexibility. Finally, halogen-bond donors are capable of competing for acceptor sites, even in the presence of strong hydrogen-bond donors. 相似文献