Introduction In this experiment, Conversion of Alcohol to Alkyl Halides and alcohol is converted to an alkyl halide through SN1 or an SN2 mechanism. This is done by using 1-propanol and 2-pentantol with HBr, Hydrobromic acid. Only half of the groups will use 1-propanol, and 2-pentantol. All results are analyzed using NMR and IR. An SN1 reaction, requires two steps. The first step, using an alcohol as an reactant, is the pronation of the –OH group from the R group. This produces a cation intermediate. The cation intermediate is attacked by the –Br group, from HBr. This is the second step. An SN2 mechanism, is only one step, unimolecular , and spontaneous. In an alcohol, the –Br group will attack at the water, H2O, is leaving the reaction. The R group attacks to the Bromine leaving an excess water. Figure 1 Mechanism for 2-Pentantol SN1
Figure 2 2-Pentantol SN2 Mechanism Nuclear Magnetic Resonance, NMR, and Infrared, IR, Spectroscopy are used to determine the structure of unknown compounds. Nuclear Magnetic Resonance allows the student to see the nuclei in a molecule by the usage of light (1). The spectrum shows how carbon can form a number of different bonds hydrogens present in the molecule, double and single. IR spectroscopy gives an idea of the frequency of the molecules through the vibrations of the molecules. Infrared shows how molecules can perform like springs which connects with Hooke’s Law. Hooke’s Law is used to describe the vibrations of springs.
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The goal of this experiment is to study the most precise way of measuring molecular bond lengths and introduction to computational software used for studying molecular properties. This is of interest in that the instrument to being used, a Fourier-transform infrared (FT-IR) spectrometer, can measure the vibrational and rotational transitions of the fundamental and first overtone of CO. Through this experiment the objective is to collect data from the aforementioned instrument in order to determine vibrational and rotational spectroscopic constants and CO’s bond length, then to
Objective: The objective of this lab is to observe the synthesis of 1-bromobutane in an SN2 reaction, to see how a primary alky halide reacts with an alcohol.
The products of the primary alcohol reaction, 1-butanol and HCl, are 1-chlorobutane and water; products of the secondary alcohol, 2-butanol and HCl are 2-chlorobutane and water; products of the tertiary alcohol, 2-methyl-2-propanol are 2-methyl-2-chloropropane and water.
The purpose of this experiment was to synthesize the Grignard reagent, phenyl magnesium bromide, and then use the manufactured Grignard reagent to synthesize the alcohol, triphenylmethanol, by reacting with benzophenone and protonation by H3O+. The triphenylmethanol was purified by recrystallization. The melting point, Infrared Spectroscopy, 13C NMR, and 1H NMR were used to characterize and confirm the recrystallized substance was triphenylmethanol.
The Purpose of this experiment is for the students to learn how to use sodium borohydride to reduce benzil to its secondary alcohol product via reduction reaction. This two-step reaction reduces aldehydes by hydrides to primary alcohols, and ketones to secondary alcohols. In order for the reaction to occur and to better control the stereochemistry and yield of the product, the metal hydride nucleophile of the reducing agents such as LiH, LiAlH4, or NaBH4 must be carefully chosen. Being that LiAlH4 and NaBH4 will not react with isolated carbon-carbon double bonds nor the double bonds from aromatic rings; the chosen compound can be reduce selectively when the nucleophile only react with
The objective of this laboratory experiment is to study both SN1 and SN2 reactions. The first part of the lab focuses on synthesizing 1-bromobutane from 1-butanol by using an SN2 mechanism. The obtained product will then be analyzed using infrared spectroscopy and refractive index. The second part of the lab concentrates on how different factors influence the rate of SN1 reactions. The factors that will be examined are the leaving group, Br versus Cl-; the structure of the alkyl group, 3◦ versus 2◦; and the polarity of the solvent, 40 percent 2-propanol versus 60 percent 2-propanol.
The purpose of this experiment was to synthesize t-pentyl chloride from the reaction of t-pentyl alcohol and concentrated HCl. This reaction occurred through an SN1 reaction, a unimolecular nucleophilic substitution reaction. This was a First Order Rate Reaction where the rate of t-pentyl chloride was dependent only on the concentration of t-pentyl alcohol. After the reaction was completed, the products were achieved via 3 liquid-liquid extractions and then after by simple distillation. In the liquid- liquid extractions a solute was transferred from one solvent to another. Then in the simple distillation the miscible liquids or the solution, was separated by differences in boiling points. After this the product was determined through infrared spectroscopy.
Using SN1 reaction mechanism with hydrochloric acid, t-Pentyl alcohol was converted to t-Pentyl chloride in an acid catalyzed reaction. The reaction took place in a separatory funnel designed to separate immiscible liquids. The crude product was extracted by transferring a solute from one solvent to another. The process of washing the solutions by phase transfer was used in order to remove impurities from the main solvent layer. Finally, the crude product was dried with anhydrous Calcium chloride and purified once more by simple distillation technique.
The solvolysis of t-butyl bromide is an SN1 reaction, or a first order nucleophilic substitution reaction. An SN1 reaction involves a nucleophilic attack on an electrophilic substrate. The reaction is SN1 because there is steric obstruction on the electrophile, bromine is a good leaving group due to its large size and low electronegativity, a stable tertiary carbocation is formed, and a weak nucleophile is formed. Since a strong acid, HBr, is formed as a byproduct of this reaction, SN1 dominates over E1. The first step in an SN1 reaction is the formation of a highly reactive carbocation, in which a leaving group is ejected. The ionization to form a carbocation is the rate limiting step of an SN1 reaction, as it is highly endothermic and has a large activation energy. The subsequent nucleophilic attack by solvent and deprotonation is fast and does not contribute to the rate law for the reaction. The Hammond Postulate predicts that the transition state for any process is most similar to the higher energy species, and is more affected by changes to the free energy of the higher energy species. Thus, the reaction rate for the solvolysis of t-butyl bromide is unimolecular and entirely dependent on the initial concentration of t-butyl bromide.
In a bimolecular nucleophilic substitution or SN2 reaction, there is only one-step. This occurs because the addition of the nucleophile and the elimination of the leaving group spontaneously occur at the same time.
The purpose of this experiment is to examine the reactivities of various alkyl halides under both SN2 and SN1 reaction conditions. The alkyl halides will be examined based on the substrate types and solvent the reaction takes place in.
In this experiment, the main objective was to synthesize a ketone from borneol via an oxidation reaction and secondly, to produce a secondary alcohol from camphor via a reduction reaction. Therefore, the hypothesis of this lab is that camphor will be produced in the oxidation reaction and isoborneol will be the product of the reduction reaction because of steric hindrance. For the oxidation step, a reflux will be done and then a microscale reflux for the reduction step. The products will be confirmed using Infrared spectroscopy, the chromic acid test, 2,4-DNP test and 13C NMR spectroscopy. The results of this
SN1 reactions are considered unimolecular nucleophilic substitution mechanisms and are a first-order process. Meaning that the reaction forms a carbocation intermediate and that the concentration of the nucleophile does not play a role in the rate-determining step, which is the slowest step in the reaction. All of the SN1 reaction mechanisms in this procedure can react two different ways. The expected mechanism for these reactions would be that the carbocation would react with the weak nucleophile nitrate, attaching the nitrogen to the positively charged carbon. However, while nitrate is the intended nucleophile in all of the reactions, it is a poor nucleophile. The ethanol used in this reaction is a polar protic ionizing solvent,
An ester was synthesized during an organic reaction and identified by IR spectroscopy and boiling point. Acetic acid was added to 4-methyl-2-pentanol, which was catalyzed by sulfuric acid. This produced the desired ester and water. After the ester was isolated a percent yield of 55.1% was calculated from the 0.872 g of ester recovered. This quantitative error was most likely due to product getting stuck in the apparatus. The boiling point of the ester was 143° C, only one degree off from the theoretical boiling point of the ester 1,3-dimethylbutyl, 144 ° C. The values of the
The purpose of this lab is to understand the process of eliminating an alkyl halide to form an alkene. The experiment is carried out by first converting the alcohol, 2-methy-2-butanol, into the alkyl halide of 2-chloro-2-methylbutane that will then be put through dehydrohalogenation that favors elimination reaction (E2) to create a mixture of 2-methyl-2-butene and 2-methyl-1-butene. A fractional distillation will be taken to purify the mixture and an additional gas chromatography will be done to further analyze the mixture composition. A bromide test will be done to determine the product of an alkene in the experiment.