Abbassi-Mohadjel| First Name:
Date: OCT. 26, 2012
| Section Number:
Objective: 1 mark
(What is the purpose of this experiment?)
In this lab, spectrochemical technique was used to determine qualitively the product of a reaction. The purpose was to learn what a SN1 reaction was with combining 2,5-dimethyl-2,5-hexanediol and HCl and to learn how to use an infrared spectrum for analyzing the reaction. The infrared spectrum determined the alcohol content present in the final product. If the IR of a molecule with an alcohol is present, there will be an IR peak between 3400 and 3200 cm^-1. However, if the experiment was done successfully by converting the alcohol to an alkly chloride, the peak should in fact disappear. The process of an SN1 reaction is described in the next question.
Introduction: 2 marks
(Brief description of the concept/reaction studied – SN1 reactions)
An SN1 reaction is a nucleophilic substitution reaction where the rate determining step of the reaction is unimolecular, thus, the rate equation is often shown as having first-order dependence on electrophile and zero-order dependence on nucleophile. This relationship holds for situations where the amount of nucleophile is much greater than that of the carbocation intermediate. The reaction (which involves a carbocation intermediate) is commonly seen in reactions of secondary or tertiary alkyl halides under strongly basic conditions or, under strongly acidic conditions (in this case strongly acidic conditions), with secondary or tertiary alcohols. In this reaction, the alcohol will be protonated by the hydrochloric acid. H2O will then “leave” the molecule in the rate-determining step, forming a relatively stable tertiary carbocation (which is highly substituted). The chloride ion, acting as a Lewis base will donate a pair of electrons to the carbocation (acting as a Lewis acid) forming the...