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 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 Hydroxyl group on alcohols relates to their reactivity. This concept was explored by answering the question “Does each alcohol undergo halogenation and controlled oxidation?” . Using three isomers of butanol; the primary 1-butanol, the secondary 2-butanol and the tertiary 2-methyl-2-propanol, also referred to as T-butanol, two experiments were performed to test the capabilities of the alcohols. When mixed with hydrochloric acid in a glass test tube, the primary alcohol and secondary alcohols were expected to halogenate, however the secondary and tertiary ended up doing so. This may have been because of the orientation of the Hydroxyl group when butanol is in a different
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.
2. SN1 and E1 reactions both involved the initial formation of a carbocation intermediate. In this experiment, why is the SN1 product favoured over the E1 product?
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 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 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.
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,
One of the most important things organic chemists do is synthesize new and complex structures from simpler structures by chemical reactions. The techniques done in
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 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.
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 purpose of this experiment was to prepare an alkyl halide, 2-chloro-2-methylbutane by reacting 2-methyl -2-butanol (t-amyl alcohol) with hydrochloric acid. Alkyl halides are of wide interest because they are widespread and have diverse beneficial and detrimental impacts .The overall reaction is given below:
The former compound is very reactive and therefore less selective, while the latter is less reactive and therefore more selective. NaBH4, which is used in this experiment, reduces only ketones and aldehydes. It produces primary alcohols from aldehydes and secondary alcohols from ketones. The reagent also reacts more rapidly with carbonyl groups than with the solvent, which is the reason it is used rather than catalytic hydrogenation or metal hydrides.
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