Preparation of T-Butyl-Chloride

2026 Words Feb 28th, 2013 9 Pages
Preparation of t-Butyl-Chloride
March 8 & 15, 2012

Theory: Alkyl halides can be synthesized when alcohols react with hydrogen halides. An alkyl halide is a halogen-substituted alkane, and a hydrogen halide is a compound consisting of a hydrogen bonded to a halogen (H-X). Alkyl halides are classified as primary, secondary, or tertiary depending on the number of alkyl substituents directly attached to the carbon bearing the halogen atom. The purpose of this laboratory experiment was to prepare t-butyl-chloride, an alkyl halide, by dissolving t-butyl alcohol in concentrated hydrochloric acid. The reaction occurs via nucleophilic substitution, in which a nucleophile replaces the leaving group in the substrate. In this case, the hydroxyl
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In Sn2 reactions, the formation of carbon-nucleophile bond and the breaking of carbon-leaving group bond occur simultaneously through a single transition state. Because the transition state involves both the nucleophile and substate, a second order reaction kinetics can be observed. It is also important to note that the nucleophile approaches the molecule from the back side, the side opposite to the leaving group, in this mechanism.
Steric effects are important in determining whether an Sn2 reaction will occur. If the molecule undergoing substitution has too many alkyl substituents, the reaction cannot occur since the nucleophile will be unable to get close enough to molecule to do a backside attack. Thereby, primary and secondary structures are able react via Sn2 mechanisms, but tertiary structures cannot because of this steric hindrance.
Tertiary structures react via Sn1. One of the factors governing Sn1 reactivity is the ability to form a stable carbocation. Alkyl substituents increase the stability of a carbocation, so increasing the alkyl substitution of the carbon atom increase the probability of an Sn1 reaction occurring. Therefore, the rate of Sn1 reactivity are as follows: tertiary > secondary > primary. Sn1 reactions occur in two steps: first being the breakdown of the alkyl halide into an alkyl carbocation and a leaving group
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