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18 Nov 2019
Questions: Answer the following questions. Be as complete as possible, and always explain your reasoning. 1. The purification step for this Grignard reaction involves removal of a major by-product, biphenyl. a) Draw the chemical structure of biphenyl. b) Which compound, biphenyl or triphenylmethanol, is more soluble in ligroin? c) Explain your answer to part (b) in terms of the polarity of both the solvent and the two compounds. Include the structural basis of all polarity assignments 2. Thin-layer chromatography (TLC) R values are dependent on compound polarity. Answer the following questions based on the TLC R values of the biphenyl and triphenylmethanol TLC standards a) Which compound is less polar, biphenyl or triphenylmethanol? Provide TLC Rt data (in either solvent system) to support your answer b) Is the answer to part (a) consistent with your conclusions in Question 1, part (c)? Why or why not? 3. To answer the following questions, consider only the thin-layer chromatography (TLC) plate that was eluted in 1:9 ethyl acetate:hexanes. a) What compound(s) were present in your crude product as indicated by TLC analysis? b) What compound(s) were present in your purified product? c) By comparing the thin-layer chromatography (TLC) results of your crude vs purified products, comment on the effectiveness of the purification procedure. Explain your answer. Consider not only the presence or absence of compound spots, but also their relative intensities
Questions: Answer the following questions. Be as complete as possible, and always explain your reasoning. 1. The purification step for this Grignard reaction involves removal of a major by-product, biphenyl. a) Draw the chemical structure of biphenyl. b) Which compound, biphenyl or triphenylmethanol, is more soluble in ligroin? c) Explain your answer to part (b) in terms of the polarity of both the solvent and the two compounds. Include the structural basis of all polarity assignments 2. Thin-layer chromatography (TLC) R values are dependent on compound polarity. Answer the following questions based on the TLC R values of the biphenyl and triphenylmethanol TLC standards a) Which compound is less polar, biphenyl or triphenylmethanol? Provide TLC Rt data (in either solvent system) to support your answer b) Is the answer to part (a) consistent with your conclusions in Question 1, part (c)? Why or why not? 3. To answer the following questions, consider only the thin-layer chromatography (TLC) plate that was eluted in 1:9 ethyl acetate:hexanes. a) What compound(s) were present in your crude product as indicated by TLC analysis? b) What compound(s) were present in your purified product? c) By comparing the thin-layer chromatography (TLC) results of your crude vs purified products, comment on the effectiveness of the purification procedure. Explain your answer. Consider not only the presence or absence of compound spots, but also their relative intensities
Lelia LubowitzLv2
11 May 2019