Preparation of T-Butyl-Chloride
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 group of t-butyl alcohol is replaced by a chlorine atom. The reaction proceeds via Sn1mechanism. The second part of the experiment consisted of purification of t-butyl chloride using the distillation process.
A nucleophile is any neutral or uncharged molecule with an unshared pair of electrons. In the substitution reaction, the nucleophile donates an electron pair to the substrate, leading to the formation of a new bond to the nucleophile, while breaking the existing bond to the leaving group. The two types of nucleophilic substitution reactions, Sn1 and Sn2, are identified based on whether these events occur simultaneously or in two separate steps. To synthesize t-butyl chloride, the t-butyl alcohol undergoes first order nucleophilic substitution, also known as SN1. To understand why t-butyl reacts via Sn1 pathway, the kinetics of the reaction mechanisms must be observed.
The steps of the nucleophilic substitution involved in the preparation of t-butyl chloride can be identified in the experiment. When concentrated hydrochloric acid is added to the t-butyl-alcohol and mixed, t-butyl chloride forms. This product is not soluble in aqueous hydrochloric acid and forms a distinct separate layer. The t-butyl chloride is less dense
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 group of t-butyl alcohol is replaced by a chlorine atom. The reaction proceeds via Sn1mechanism. The second part of the experiment consisted of purification of t-butyl chloride using the distillation process.
A nucleophile is any neutral or uncharged molecule with an unshared pair of electrons. In the substitution reaction, the nucleophile donates an electron pair to the substrate, leading to the formation of a new bond to the nucleophile, while breaking the existing bond to the leaving group. The two types of nucleophilic substitution reactions, Sn1 and Sn2, are identified based on whether these events occur simultaneously or in two separate steps. To synthesize t-butyl chloride, the t-butyl alcohol undergoes first order nucleophilic substitution, also known as SN1. To understand why t-butyl reacts via Sn1 pathway, the kinetics of the reaction mechanisms must be observed.
The steps of the nucleophilic substitution involved in the preparation of t-butyl chloride can be identified in the experiment. When concentrated hydrochloric acid is added to the t-butyl-alcohol and mixed, t-butyl chloride forms. This product is not soluble in aqueous hydrochloric acid and forms a distinct separate layer. The t-butyl chloride is less dense
Bibliography: Macroscale and Microscale Organic Experiments. 6th ed. Williamson, Minard, and Masters, Houghton Miffin Co, 2007. Organic Chemistry, 10th edition, Solomon and Fryhle. John Wiley & Sons, Inc., 2011