IR - Introduction Cyclohexene was synthesized from...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Introduction Cyclohexene was synthesized from cyclohexanol by the method of dehydration to obtain a percent yield of 43.6% and theoretical yield of 7.889 g. The product was then characterized using IR, or infrared spectroscopy. The product indicated cyclohexane was present and included single carbon-hydrogen bonds (Csp3-H) from 2837.73-2924.93, and double carbon-hydrogen bonds (Csp2-H) with a wave number of 3022.28. . Theory, Reactions, and Mechanisms An alkene is distinguished from other functional groups by having at least one double bond consisting of a sigma and a Pi bond between two adjacent carbons in the molecule. The two carbons are sp2 hybridized. The general formula for alkenes with only one double bond in the molecule is C n H 2n , where n is the number of carbon atoms in the molecule. The more substituated the double bond is, the more stable the alkene. Alkenes can be synthesized by different kinds of reactions that include reduction of alkynes, Aldol condensations, Wittig reactions, and elimination reactions. Elimination reactions, of which there are two kinds: E1 and E2, are used extensively in organic chemistry to synthesize alkenes. In an elimination reaction, a hydrogen atom is removed as it is attacked by a basic nucleophile, resulting in a double bond between the two adjacent carbons (see figure 1). Figure 1. Elimination reaction.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Of the two types of elimination reactions E1, or unimolecular elimination, occurs mostly in the presence of a weakly basic nucleophile, most frequently as a solvent. The mechanism of an E1 reaction involves the removal of the leaving group resulting in the formation of a carbocation, the rate determining step of the reaction. Carbocation stability increases from tertiary to primary. This step is followed by the attack of the base on a hydrogen atom adjacent the carbon atom of the carbocation. A double bond is then formed between the two carbon atoms ( see figure). The reaction rate can be obtained by the equation: Rate= k[A] where k is equal to the rate constant and [A] is the concentration of substrate. The solvent used in an E1 reaction is one that stabilizes the carbocation. This would be a polar protic solvent which is a solvent that can hydrogen bond, such as H2O or ethanol. A polar solvent is favored over non-polar solvent due to the increasing polarity that stabilizes that carbocation. A good leaving
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 01/08/2009 for the course CHEM 0320 taught by Professor Kazunorikoide during the Spring '08 term at Pittsburgh.

Page1 / 9

IR - Introduction Cyclohexene was synthesized from...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online