In chemical recipes, there are guidelines for efficient chemical production typically based on chemistry. However, such guidelines have never been checked with engineering methodologies for the sake of sustainability. A methodology is presented here on the case study problem of Grignard reagent production using tetrahydrofuran (THF) as a solvent with water contents of 1000 and 10,000 ppm. Two possibilities of dewatering are studied: preliminary distillation and chemical reaction. The USEtox environmental impact assessment method is applied for the environmental study and the Environmental Priority Strategies (EPS) method is chosen for the economic estimation to express the environmental damage in monetary value. The life cycle analysis does not detect considerable differences between the two dewatering alternatives. However, the conclusion of the economic assessment shows concentration dependence. In the case of higher water content, distillation-based dewatering is recommended. The methodology delivers the same results like the chemical recipe; that is, the safety value of the water content of THF is uniformly 0.08 mol % where no dewatering is recommended. This work clearly demonstrates that the chemical recipes should be reconsidered and justified or modified also with comprehensive engineering studies.

中文翻译：

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当化学与工程学相遇时：四氢呋喃脱水案例研究

在化学配方中，有一些通常基于化学方法进行有效化学生产的指南。但是，出于可持续性考虑，从未使用工程方法来检查此类指南。本文介绍了使用四氢呋喃（THF）作为水含量分别为1000和10,000 ppm的溶剂生产格氏试剂的案例研究问题的方法。研究了两种脱水方法：预蒸馏和化学反应。将USEtox环境影响评估方法用于环境研究，并选择环境优先策略（EPS）方法进行经济评估，以货币价值表示环境损害。生命周期分析未发现这两种脱水方案之间的显着差异。然而，经济评估的结论显示出集中度依赖性。如果含水量较高，建议使用基于蒸馏的脱水。该方法可提供与化学配方相同的结果。即，在不建议脱水的情况下，THF的含水量的安全值均匀地为0.08mol％。这项工作清楚地表明，化学配方还应通过全面的工程研究加以重新考虑，论证或修改。