Resolution Of Trans-Cyclohexane Lab Report
Name: Leigh O’Neill
Date: 10th February 2015
Lab Partner: Sinead Murphy
Title: Resolution of Trans-Cyclohexane-1,2-diamine
Abstract: The experiment of resolution of Trans-Cyclohexane-1,2-diamine was completed using recrystallization. This produced a percentage yield of 85% from a theoretical yield of 2.638g.
Introduction:
Enantiomers are identical and equal in their physical properties except for optical rotation which can be viewed by polarimetry. Diastereomers have different densities, melting points, Gibb’s Free energy, among other physical properties. This allows for the diastereomers to be identified as + or – and allows them to be studied individually. An enantiomer has more than one chiral centre it will have more than 1 diastereomer …show more content…
Questions:
The configuration of the Chiral Centres of L-(+)-tartaric acid: Number 1 is given to the –OH molecule, as the atomic number of oxygen is larger than the remaining molecules. Number 4 is given to the Hydrogen, as it is the lowest priority and lowest atomic number. Number 3 is given to COOH as it is bonded to lower priorities than then centre Carbon atoms. Which leaves number 2 to the centre carbon atoms.
The two enantiomers of trans-1, 2-diaminocyclohexane Apart from melting point analysis, what other experimental technique could be used to determine which specific enantiomer you have isolated? How would the results observed for each enantiomer differ using this technique? Briefly explain your answer.
The experimental technique that could be used to identify the enantiomer isolated is polarimetry. In polarimetry both enantiomers are oscillated a specific rotation to equal degree but it will change sign (it will be positive or negative) depending on the enantiomer. …show more content…
This could be improved by adding more methanol to the mixture before isolation. The mixture could also stay in the water bath for longer than 45 minutes to allow an adequate time for the tartaric salt to form. An extra 30ml of methanol was added to this experiment to get the tartaric salt to form and if more methanol was added, a higher percentage yield might have been obtained. The literature value for the melting point of tartaric salt is 252-267℃. The value obtained experimentally did not fall within this range.
References:
2nd Year Laboratory Manual for School of Chemical and Pharmaceutical Sciences page 85 http://chemwiki.ucdavis.edu/Organic_Chemistry/Organic_Chemistry_With_a_Biological_Emphasis/Chapter_03%3A_Conformations_and_Stereochemistry/Section_3.6%3A_Optical_activity Journal -A new approach to enantiomerically pure bis-imidazoles derived from trans-1,2-diaminocyclohexane” Section 4.7.1 Paulina Macha, Grzegorz Mlowton et al: 13 June 2008.
Date: 10th February 2015
Lab Partner: Sinead Murphy
Title: Resolution of Trans-Cyclohexane-1,2-diamine
Abstract: The experiment of resolution of Trans-Cyclohexane-1,2-diamine was completed using recrystallization. This produced a percentage yield of 85% from a theoretical yield of 2.638g.
Introduction:
Enantiomers are identical and equal in their physical properties except for optical rotation which can be viewed by polarimetry. Diastereomers have different densities, melting points, Gibb’s Free energy, among other physical properties. This allows for the diastereomers to be identified as + or – and allows them to be studied individually. An enantiomer has more than one chiral centre it will have more than 1 diastereomer …show more content…
Questions:
The configuration of the Chiral Centres of L-(+)-tartaric acid: Number 1 is given to the –OH molecule, as the atomic number of oxygen is larger than the remaining molecules. Number 4 is given to the Hydrogen, as it is the lowest priority and lowest atomic number. Number 3 is given to COOH as it is bonded to lower priorities than then centre Carbon atoms. Which leaves number 2 to the centre carbon atoms.
The two enantiomers of trans-1, 2-diaminocyclohexane Apart from melting point analysis, what other experimental technique could be used to determine which specific enantiomer you have isolated? How would the results observed for each enantiomer differ using this technique? Briefly explain your answer.
The experimental technique that could be used to identify the enantiomer isolated is polarimetry. In polarimetry both enantiomers are oscillated a specific rotation to equal degree but it will change sign (it will be positive or negative) depending on the enantiomer. …show more content…
This could be improved by adding more methanol to the mixture before isolation. The mixture could also stay in the water bath for longer than 45 minutes to allow an adequate time for the tartaric salt to form. An extra 30ml of methanol was added to this experiment to get the tartaric salt to form and if more methanol was added, a higher percentage yield might have been obtained. The literature value for the melting point of tartaric salt is 252-267℃. The value obtained experimentally did not fall within this range.
References:
2nd Year Laboratory Manual for School of Chemical and Pharmaceutical Sciences page 85 http://chemwiki.ucdavis.edu/Organic_Chemistry/Organic_Chemistry_With_a_Biological_Emphasis/Chapter_03%3A_Conformations_and_Stereochemistry/Section_3.6%3A_Optical_activity Journal -A new approach to enantiomerically pure bis-imidazoles derived from trans-1,2-diaminocyclohexane” Section 4.7.1 Paulina Macha, Grzegorz Mlowton et al: 13 June 2008.