Williamson Ether Synthesis- Preparation of Methyl p-ethylphenyl ether - Lab Report Example

Williamson Ether Synthesis – Preparation of Methyl p-ethyl Phenyl Ether The chief objective of this experiment is to perform a nucleophilic substitution reaction on a methyl halide using a deprotonated alcohol to produce ether. Actually, this experiment seeks to demonstrate the practical side of William ether synthesis procedure. Through the experiment, the applicability of SN2 reaction in product synthesis can be demonstrated. Independent procedures of the Williamson ether synthesis method involved cleaning of reactants, production of intermediate compounds, isolation of products, and characterization of the resultant products through analytical techniques like nuclear magnetic resonance.

At the end of the experiment, methyl p-ethyl phenyl ether was produced and quantitatively identified as the desired product. In conclusion, it was ascertained that all the procedures and reaction conditions employed throughput the reaction were instrumental in influencing the quality and quantity of the resultant ether.IntroductionTechnically, Williamson Synthesis process is one of the effective methods used in the synthesis of ethers. Unlike other ether-synthesis processes, Williamson Synthesis is particularly suited for production of ethers with both symmetrical and unsymmetrical molecular structures (Mayo et al, 322).

In chemistry, ethers are important compounds applied in a variety of ways including but not limited to dissolution of organic compounds, and formation of organic linkages. This experiment involves a practical examination of ether synthesis. Williamson ether synthesis is the most widely and simplest method in ether synthesis. Despite its simplicity and wide applicability, this method fails to yield desirable products whenever a parent alcohol is treated with a secondary or tertiary halide. Technically, the limited applicability of Williamson ether synthesis is attributed to the method’s mechanism, which is a typical SN2 reaction.

This experiment is an explicit demonstration of SN2 reaction mechanism, especially those requiring phase-transfer catalysts. Use of phase-transfer catalysis is meant to increase favorability of SN2 reaction over E2 elimination, which is a characteristic problem whenever secondary and tertiary alkyl halides are used in ether production (Mayo et al, 322). In this experiment, the desired product is methyl p-ethyl phenyl ether. In the experiment, the reagents were ethyl phenol as a parent alcohol, and methyl iodide as the primary halide.

Despite being a primary halide, a phase-transfer catalyst was instrumental in increasing the yield of the desired ether. Chemical equation for the ether synthesis is;CH3CH2C6H5OH (ethyl phenol) + CH3 – I (methyl iodide) → CH3CH2C6H5-O-CH3 (methyl p-ethyl phenyl ether)Prior to treatment of the ethyl phenol with the halide, the alcohol was treated with a base, particularly NaOH, to yield an alkoxide. Subsequently, the alkoxide initiated a nucleophilic attack on the methyl halide, forming the desired ether.

Subsequent sections of the report documents detailed procedures used in preparation, purification and characterization of the resultant ether. Post Lab QuestionQuestion 6-144In the synthesis of sulfides, isopropyl bromide possesses less steric hindrance compared to 2-bromo-1-nitropropane. The reaction of both alkyl halides involves a nucleophilic attack (Smith, 24). In this case, the less hindered isopropyl bromide is easily attacked by the nucleophile compared to 2-bromo-1-nitropropane.Question 6-145 Upon treatment of 3-bromo-1-propanol with NaOH, an alkoxide is formed.

A suggested structure for this resultant alkoxide is CH3CH2C=OH.Question 6-146The rate of increasing reactivity for the substituted phenols toward ethyl iodide is b-a-c. Increase in reactivity with the alkyl halide is attributed to increase in electron density from b to c. With respect to deprotonation, the rates reverse from (slowest) c-a-b (fastest). Question 6-147A reaction between alcohols and strong bases like NaOH produce an alkoxide. However, the rate of alkoxide formation varies with each type of alcohol involved.

Occasionally, some alcohols fail to produce an alkoxide. For example, cis-2-Chlorocyclohexanol resists a nucleophilic metal attack because of a strong hydrogen bonding in the compound’s geometric structure (Starkey, 37). Contrarily, trans-2-Chlorocyclohexanol easily produces Cyclohexene oxide because trans-isomers have weaker hydrogen bonding compared to cis-isomers, thus trans-isomers are more susceptible to nucleophilic attacks from metals. Question 6-148Undeniably, both methods are viable in preparation of tert-Butyl ethyl ether.

However, I would choose the use of CH3CH2Cl as the alkyl halide over (CH3)3CCl. CH3CH2Cl is a primary alkyl halide while (CH3)3CCl is a tertiary alkyl halide. During the SN2 reaction of the alkoxide with alkyl halide to produce the ether, the primary halide will suffer less from E2 side reactions compared to the tertiary alkyl halide (Smith, 19). Question 6-149Technically, tetrahydrofuran is cyclic ether. When excess hydrogen halide like HI acid reacts with the ether, halo alkyl alcohols are formed.

In this case, use of excess HI on THF produces 4-iodo pentyl alcohol. Works CitedMayo Dana, Pike Ronald and Forbes, David. Micro-scale Organic Laboratory: With multi-step and multi-scale syntheses. Pittsburg: John Wiley & Sons, 2010. Print. Smith, Lawrence. Organic Reactions: Mechanisms with problems. New York, NY: Discovery Publishing House, 2005. Print. Starkey, Laurie. An Introduction to Experiments for Organic Synthesis. Pittsburg: John Wiley & Sons, 2012. Print.