Grignard Reagent Lab Report

In part A, the Grignard reagent was created. Mg is added between the benzene ring and the bromine by means of a non-chain radical reaction. Initially, Mg donates and electron to bromide and heterolytically breaks the C-Br bond; therefore, this results in a carbon radical, Br - ion, and a Mg+ radical. Next, the carbon radical and the Mg+ radical bond together, and the Mg and Br - ionically bond together2. In the experiment, no initial color change to cloudy gray was observed. Eventually, it was decided to try and

Discussion: In the synthesis of 1-bromobutane alcohol is a poor leaving group; this problem is fixed by converting the OH group into H2O, which is a better leaving group. Depending on the structure of the alcohol it may undergo SN1 or SN2. Primary alky halides undergo SN2 reactions. 1- bromobutane is a primary alkyl halide, and may be synthesized by the acid-mediated reaction of a 1-butonaol with a bromide ion as a nucleophile. The proposed mechanism involves the initial formation of HBr in situ, the protonation of the alcohol by HBr, and the nucleophilic displacement by Br- to give the 1-bromobutane. In the reaction once the salts are dissolved and the mixture is gently heated with a reflux a noticeable reaction occurs with the development of two layers. When the distillation was clear the head temperature was around 115oC because the increased boiling point is caused by co-distillation of sulfuric acid and hydrobromic acid with water. When transferring allof the crude 1-bromobutane without the drying agent,

During the halogenation reactions of 1-butanol, 2-butanol, and 2-methyl-2-propanol, there is a formation of water from the OH atom of the alcohol, and the H atom from the HCl solution. The OH bond of the alcohol is then substituted with the Cl atom. Therefore all of the degrees of alcohol undergo halogenation reactions, and form alkyl halides as products. This is because the functional group of alkyl halides is a carbon-halogen bond. A common halogen is chlorine, as used in this experiment.

Grignard reagents also react with the least hindered carbon on an epoxide to break the ring in order to relieve ring strain.

The reaction involves a nucleophilic acyl substitution on an aldehyde, with the leaving group concurrently attacking another aldehyde in the second step. First the Potassium hydroxide attacks a carbonyl, which forms a tetahedral intermediate which then collapses when attacked by another hydroxide. The carbonyl is formed again when its hydride attacks another carbonyl. In the final step of the reaction, the acid and alkoxide ions formed exchange a proton. In the presence of a very high concentration of base, the aldehyde first forms a doubly charged anion from which a hydride ion is transferred to the second molecule of aldehyde to form carboxylate and alkoxide ions. Subsequently, the alkoxide ion acquires a proton from the solvent.

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.

After 10 minutes the reaction liquid was separated from the solid using a vacuum filtration system and toluene. The product was stored and dried until week 2 of the experiment. The product was weighed to be 0.31 g. Percent yield was calculated to be 38.75%. IR spectra data was conducted for the two starting materials and of the product. Melting point determination was performed on the product and proton NMR spectrum was given. The IR spectrum revealed peaks at 1720 cm-1, which indicated the presence of a lactone group, and 1730 cm-1, representing a functional group of a carboxylic acid (C=O), and 3300cm-1, indicating the presence of an alcohol group (O-H). All three peaks correspond with the desired product. A second TLC using the same mobile and stationary phase as the first was performed and revealed Rf Values of 0.17 and 0.43for the product. The first value was unique to the product indicating that the Diels-Alder reaction was successful. The other Rf value of 0.43 matched that of maleic anhydride indicating some

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.

Additionally, creating a dry environment for the reaction tried to reduce the formation of side products. One possible side product was benzene, which was formed during the protonation of the carbanion on the benzene ring during the formation of the Grignard reagent4. The carbanion was very basic meaning that if there was any water in the glassware or moist air in the environment, some of the carbanion will be protonated by the water creating benzene instead of

The Grignard reaction is an important synthetic process by which a new carbon to carbon bond is formed. Magnesium metal is first reacted with an organic halide forming the Grignard reagent. The Grignard reaction is the addition of an organomagnesium halide (Grignard reagent) to a ketone or aldehyde, to form a tertiary or secondary alcohol, respectively. For example, the reaction with formaldehyde leads to a primary alcohol. Grignard Reagents are also used in the following important reactions: The addition of an excess of a Grignard reagent to an ester or lactone gives a tertiary alcohol in which two alkyl groups are the same, and the addition of a

There are four main regions of IR absorptions: region 4000 – 3000 cm-1 corresponds to N-H, C-H and O-H stretching, region 2250- 2100 cm-1 is triple-bond stretching , region 2000- 1500 cm-1 is double bonds and the region below 1500 cm-1 is the fingerprint region where a variety of single bonds are absorbed.3 The chromic acid test is a test for oxidizability and gives a positive result for primary and secondary alcohols as well as aldehydes2. A positive result in the chromic acid test is indicated by a color change and the formation of a precipitate. Tertiary alcohols give negative results for the chromic acid test since there must be a hydrogen present on the alcoholic carbon for oxidation to occur. The 2,4 DNP test, tests for a carbonyl and is therefore a dependable test for aldehydes and ketones. Finally, 13C NMR spectroscopy is a test to determine the structure of a compound. 13C NMR detects the 13C isotope of carbon. Each carbon has a different chemical shift. A carbon’s chemical shift is affected by the electronegativity of nearby atoms. Carbons that are bonded to highly electronegative atoms resonant downfield because the electronegative atom pulls electrons away from the nearby carbons and cause those carbons to resonant downfield1 (John McMurry, 2008). A general trend is that sp3-hybridized carbons absorb from 0 to 90 ppm, sp2-hybridized carbons resonant between 110

The reaction took place in a conical vial and .2mL of each of the reactant samples were added to it along with some 95% ethanol. Two drops of NaOH were added shortly after and stirred at room temperature for fifteen minutes. The vial was cooled in and ice bath and crystallized. Vacuum filtration was performed to filter the crude product. The crude product was recrystallized using methanol and filtered again. We made one change to the procedure and instead of using .7mL of ethanol we

Through the use of the Grignard reaction, a carbon-carbon bond was formed, thereby resulting in the formation of triphenylmethanol from phenyl magnesium bromide and benzophenone. A recrystallization was performed to purify the Grignard product by dissolving the product in methanol. From here, a melting point range of 147.0 °C to 150.8 °C was obtained. The purified product yielded an IR spectrum with major peaks of 3471.82 cm-1, 3060.90 cm-1, 1597.38 cm-1, and 1489.64 cm-1, which helped to testify whether the identity of the product matched the expected triphenylmethanol. The identity of the product being correct was further confirmed by way of both proton and carbon-13 NMR spectra. This is due to the fact

There's a variety of different types of chemical reactions, but the ones I'm going to name down low are the main points of chemical reactions. The names of the different types of reactions is Decomposition, Combustion, Acid/base,Synthesis,Single-Replacement, Double- Replacement and Precipitation. Decomposition is one of the eight chemical reactions. Decomposition is when you get something complex and break it down into smaller molecules. Decomposition is the opposite of synthesis reaction.

The purposed of this investigation was to performed activities and interpret results on different tests such as Benedict’s test, Iodine test, Biuret test, Paper test on various foods such as banana, coconut milk, whole milk, peanut and potato as to what type of macromolecules (sugar, protein, starch, lipid) they have. I have come to a conclusion that when a reagent (Benedict’s reagent, Iodine reagent, Biuret reagent) was mixed with any type of solution, there is a reaction/ effect that takes in place once there is a presence of any type of macromolecule.