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The acid-catalyzed dehydration of regioisomeric methylcyclohexanols is a classic organic chemistry experiment featured in a variety of laboratory textbooks and literature. The mechanistic details of this reaction have received an inconsistent and occasionally inaccurate treatment, wherein the reaction has been described as a mix of E1, E2-like, acid-catalyzed E2, and base-catalyzed E2 processes. We provide an overview of how this reaction has been represented in the chemistry education literature and describe a model for its mechanistic interpretation as an E1 reaction that is typically analyzed before thermodynamic equilibrium is established. This model is supported by new experimental data and computational explorations of the reactive intermediates and cycloalkene products. We provide clear recommendations for how this reaction should be presented to students.

The affordances given to a structured, timed, and proctored paper exam are not as readily applicable in a digital medium. Accordingly, the rapid shift from in-person to online enactments may have forced instructors to consider changing their assessment practices and priorities. As assessments convey strong implicit messages about "what counts" in a given learning environment, altering what is assessed may have a profound impact on what students view as important in a course. Our four-instructor team sought to examine whether we were able to maintain emphasis on assessing "how" and "why" chemical phenomena occur online while minimizing negative impacts to students, teaching assistants, and ourselves. To support claims regarding the degree to which online assessments emphasized sensemaking relative to past exams, we characterized all summative assessments given in organic chemistry II enactments from 2016 to the present using the three-dimensional learning assessment protocol. To examine the impact of enrolling in a rapidly assembled online organic course on student outcomes, we examined the distribution of students who performed above, at, or below the final exam score predicted by their midterm performance and compared this distribution with historic norms. Results suggest that we were able to maintain emphasis on student sensemaking as our course moved online (~50% of points on exams administered remotely were dedicated to 3D performances). Additionally, the distribution of students enrolled this past spring who scored above, at, or below the final exam score predicted by their midterm performance was in line with historic norms. When taken in aggregate, our analyses suggest that organic chemistry-enrolled students maintained their ability to make sense of chemical phenomena after the pivot to online instruction. Consistent emphasis on assessing 3D learning online was achieved without adding appreciably to the burden on instructors or teaching assistants due to our assessment writing practices, streamlined approach to online grading, and pre-existing course resources. Instructional implications for assessment design, enacting team grading, and tracking student trajectories are provided in addition to a suite of assessment items with the potential to engage students in sensemaking.

A set of inexpensive and pedagogically rich experiments focusing on S[subscript N]1, E1, and E2 reactions have been updated to include modern computational and spectroscopic analyses. The S[subscript N]1 experiment involves treatment of "tert"-amyl alcohol with hydrochloric acid to generate the corresponding alkyl chloride, which is used as the starting material for the subsequent E2 reaction. The E1 experiment involves reaction of "tert"-amyl alcohol with sulfuric acid. Both elimination reactions generate a pair of isomeric methylbutenes, with the ratio being dependent on the reaction mechanism. The combination of computational chemistry and a recently developed fast heteronuclear single-quantum correlation spectroscopy method (ASAP-HSQC), in tandem with [superscript 1]H and [superscript 13]C NMR and GC-MS analysis, allows the E1 and E2 product mixtures to be fully analyzed by students.

Animal‐sourced hydrogels, such as collagen, are widely used as extracellular‐matrix (ECM) mimics in tissue engineering but are plagued with problems of reproducibility, immunogenicity, and contamination. Synthetic, chemically defined hydrogels can avoid such issues. Despite the abundance of collagen in the ECM, synthetic collagen hydrogels are extremely rare due to design challenges brought on by the triple‐helical structure of collagen. Sticky‐ended symmetric self‐assembly (SESSA) overcomes these challenges by maximizing interactions between the strands of the triple helix, allowing the assembly of collagen‐mimetic peptides (CMPs) into robust synthetic collagen nanofibers. This optimization, however, also minimizes interfiber contacts. In this work, symmetric association states for the SESSA of short CMPs to probe their increased propensity for interfiber association are modelled. It is found that 33‐residue CMPs not only self‐assemble through sticky ends, but also form hydrogels. These self‐assemblies behave with remarkable consistency across multiple scales and present a clear link between their triple‐helical architecture and the properties of their hydrogels. The results show that SESSA is an effective and robust design methodology that enables the rational design of synthetic collagen hydrogels. [ABSTRACT FROM AUTHOR]