A More Challenging Interpretative Nitration Experiment Employing Substituted Benzoic Acids and Acetanilides

Treadwell, Edward M.; Lin, Tung Yin

doi:10.1021/ed085p1541

Cited by 5 publications

(6 citation statements)

References 1 publication

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“…After students become familiar with GaussView through the guided sessions, they are asked to complete a molecular modeling exercise as part of a later laboratory experiment 28 without an animated tutorial and can typically complete this task with minimal help from the instructor.…”

Section: Gaussviewmentioning

confidence: 99%

Web-Based Animated Tutorials Using Screen Capturing Software for Molecular Modeling and Spectroscopic Acquisition and Processing

2018

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Instructional videos have been prepared using Adobe Captivate software to create animated tutorials to capture instrument and molecular modeling software simulations and to allow for increased independent hands-on instrument use by students and faster training for instructors and teaching assistants. The videos are available on YouTube and can be viewed prior to or synchronously as students are acquiring an IR spectrum, processing an 1H NMR spectrum, or performing specific calculations using GaussView. Student surveys indicate preference for the animated tutorials over conventional paper instructions and general favorability of the videos.

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Section: Gaussviewmentioning

confidence: 99%

Web-Based Animated Tutorials Using Screen Capturing Software for Molecular Modeling and Spectroscopic Acquisition and Processing

2018

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“…The earlier method used for the quantitative determination of the regioselectivity of this reaction in laboratory exercises [1,2] and class room demonstrations [3] is the gas chromatographic (gc) analysis of the product mixture. A newer method that has been reported for determining mole ratios of binary mixtures of conformers [4], tautomers [5], stereoisomers [6,7,8,9] and regioisomers [6,7,10,11,12,13] is high resolution 1 H NMR spectroscopy. This method is faster, simpler to use, more direct and accurate for the determination of the mole ratio of mixtures than the gas chromatographic method.…”

Section: Introductionmentioning

confidence: 99%

“…The most relevant reported examples of this application of quantitative NMR spectroscopy, however, analyzed regio-isomeric ratios of pre-purified solid EAS reaction products. Purification steps such as recrystallization [10] or trituration [12], however, alter the actual product ratios because of different solubilities in the solvent used. We report here the use of high resolution 1 H NMR spectroscopy to determine the actual o/p reaction products ratios in EAS reactions from which only the reaction solvent has been removed by evaporation.…”

Section: Introductionmentioning

confidence: 99%

Determination of the p/o-Isomer Product Ratios in Electrophilic Aromatic Nitration of Alkylbenzenes Using High Resolution 1H NMR Spectroscopy

Waddell¹,

Bump²,

Ndip³

et al. 2019

WJCE

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High resolution 1 H NMR spectroscopy, an increasingly available instrumental method, is used in undergraduate organic laboratory practice as a simpler alternative to gas chromatographic method for the direct determination of the p/o ratios of the crude reaction product from the nitration of alkylbenzenes. The choice of isopropylbenzene as a substrate illustrates that steric effect can be significant in controlling regioselectivity in electrophilic aromatic substitution reactions.

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“…Regioselectivity in aromatic substitutions is typically explored with aromatic substrates that afford unambiguous determination of the regioselectivity of the products by 1 H/ 13 C NMR spectra or the students are provided the identity of the various isomers either by GC or IR spectroscopy. − The experiment introduced here illustrates the utility of the 1 H 1-D selective NOE experiment for solving structural ambiguities more akin to real life synthetic problems facing today’s chemists. Although there are several two-dimensional (2-D) NOE experiments in the literature for advanced organic/bioorganic structure determination − and also a 1-D NOE difference experiment, no examples of 1-D selective NOE experiments were found in this Journal .…”

Section: Introductionmentioning

confidence: 99%

1-Dimensional Selective Nuclear Overhauser Effect NMR Spectroscopy To Characterize Products from a Two-Step Green Chemistry Synthesis

2018

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One dimensional (1-D) 1H and 13C NMR experiments are common tools used in undergraduate organic laboratories to characterize synthesized molecules. However, 1-D NMR spectra cannot always provide unambiguous structure determination. In research laboratories, advanced NMR spectroscopy methods are employed for structural assignments of synthesized molecules. This experiment is designed to introduce undergraduate students to the application of an advanced method of 1H NMR spectroscopy, the 1-D selective nuclear Overhauser effect (NOE) experiment, to fully characterize the structure of two compounds. The experiment features a two-step green chemistry synthesis to produce the two compounds. In the first step of the synthesis, 4-methylaniline (para-toluidine) is acetylated to form 4′-methylacetanilide (para-acetotoluidide). The 1-D selective NOE method is used to identify the two different methyl groups present in 4′-methylacetanilide and to assign the aromatic protons. For the second step of the synthesis, bromination of the aromatic ring of 4′-methylacetanilide is accomplished using Oxone and ammonium bromide in an aqueous solvent. The 1-D selective NOE method is applied to determine the regioselective product of the bromination reaction. The 1-D selective NOE experiment is readily accessible and easily implemented. Successful interpretation of the 1-D selective NOE results leaves students confident in making structural assignments that would otherwise be based solely on theory or software prediction.

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A More Challenging Interpretative Nitration Experiment Employing Substituted Benzoic Acids and Acetanilides

Cited by 5 publications

References 1 publication

Web-Based Animated Tutorials Using Screen Capturing Software for Molecular Modeling and Spectroscopic Acquisition and Processing

Web-Based Animated Tutorials Using Screen Capturing Software for Molecular Modeling and Spectroscopic Acquisition and Processing

Determination of the <i>p</i>/<i>o</i>-Isomer Product Ratios in Electrophilic Aromatic Nitration of Alkylbenzenes Using High Resolution <SUP>1</SUP>H NMR Spectroscopy

1-Dimensional Selective Nuclear Overhauser Effect NMR Spectroscopy To Characterize Products from a Two-Step Green Chemistry Synthesis

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