“It’s Only the Major Product That We Care About in Organic Chemistry”: An Analysis of Students’ Annotations of Reaction Coordinate Diagrams,Journal of Chemical Education

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“It’s Only the Major Product That We Care About in Organic Chemistry”: An Analysis of Students’ Annotations of Reaction Coordinate Diagrams
Journal of Chemical Education ( IF 2.5 ) Pub Date : 2018-06-16 00:00:00 , DOI: 10.1021/acs.jchemed.8b00153
Maia Popova ₁ , Stacey Lowery Bretz ₁

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The purpose of this study was to analyze organic chemistry students’ annotations of reaction coordinate diagrams to better understand how they sought connections between reactions and reaction coordinate diagrams. Thirty-six students enrolled in Organic Chemistry II participated in semistructured, think-aloud interviews that asked students to choose a reaction coordinate diagram from a set of three possible diagrams to match a substitution reaction mechanism and then to match an elimination reaction mechanism. Students’ annotations of the reaction coordinate diagrams provided in the interviews, and in some cases additional reaction coordinate diagrams generated by the students themselves, were examined. Qualitative analyses indicated that half of the participants considered only the “major” species (reactant, intermediate, and product) to be encoded in reaction coordinate diagrams, whereas the rest of the reaction species (leaving groups, nucleophiles/bases, and solvent molecules) were omitted from their drawings. These findings suggest that because organic chemists frequently write equations that are balanced neither in mass nor in charge, and because these equations tend to focus upon the formation of the major product, students can develop the idea that only the “major” chemical species are important to focus upon when interpreting the symbolic representations of reactions and reaction coordinate diagrams. The implications of these findings for classroom teaching are discussed.

中文翻译：

“这是我们在有机化学中唯一关心的主要产品”：对学生反应坐标图注释的分析

这项研究的目的是分析有机化学专业学生对反应坐标图的注释，以更好地理解他们如何寻求反应与反应坐标图之间的联系。参加有机化学II课程的三十六名学生参加了半结构化的思考式访谈，该访谈要求学生从三个可能的图中选择一个反应坐标图，以匹配取代反应机理，然后匹配消除反应机理。检查了学生在访谈中提供的反应坐标图的注释，在某些情况下还检查了学生自己生成的其他反应坐标图。定性分析表明，一半的参与者只考虑了“主要”物种（反应物，中间物，和产物）编码在反应坐标图中，而其余的反应物种（离去基团，亲核试剂/碱和溶剂分子）从图中省略。这些发现表明，由于有机化学家经常写出既不平衡质量也不平衡电荷的方程式，并且由于这些方程式倾向于集中于主要产物的形成，因此学生可以发展出这样的观念，即只有“主要”化学物种才是重要的。在解释反应和反应坐标图的符号表示时要重点关注。讨论了这些发现对课堂教学的意义。这些发现表明，由于有机化学家经常写出既不平衡质量也不平衡电荷的方程式，并且由于这些方程式倾向于集中于主要产物的形成，因此学生可以发展出这样的观念，即只有“主要”化学物种才是重要的。在解释反应和反应坐标图的符号表示时要重点关注。讨论了这些发现对课堂教学的意义。这些发现表明，由于有机化学家经常写出既不平衡质量也不平衡电荷的方程式，并且由于这些方程式倾向于集中于主要产物的形成，因此学生可以发展出这样的观念，即只有“主要”化学物种才是重要的。在解释反应和反应坐标图的符号表示时要重点关注。讨论了这些发现对课堂教学的意义。

更新日期：2018-06-16

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