Grignard Reaction Lab Report

Any amount of H2O present would react with and therefore ruin the Grignard reagent. The negative charge on the Grignard carbon would pop a proton off of water, and the resulting hydroxide would react with MgBr2. Since all of the water and moisture was removed, the reaction should run successfully. For this experiment’s reaction, bromobenzene is turned into phenylmagnesium bromide, a Grignard reagent. Then, the Grignard reagent is reacted with benzophenone to yield a molecule with a negative charge on the oxygen. This molecule is worked up and protonated to yield triphenylmethanol.

Different procedures were used to isolate benzil from the ether layer and benzoic acid from the aqueous layers. To isolate benzil, anhydrous MgSO4 was added to the flask containing the ether layer solution. MgSO4 removes the remaining water in the ether layer solution. After making sure that enough amount of MgSO4 present in the solution, the ether solution was filtered by using gravity filtration. During filtration, MgSO4 was removed from the solution and the ether solution was collected in 25 ml flask. To separate benzil from the filtered ether solution, the beaker containing the ether solution was heated until the ether evaporated. After letting the beaker to cool to room temperature, the mass of the beaker with the benzil crystals was measured. From the combined mass of the beaker and the benzil crystals and from the predetermined mass of the beaker, the mass of the collected crystals was calculated to be 0.266 gram.

A Grignard reagent is a type of organometallic, which consists of a bond between a metal and a carbon. There are three types of carbon-metal bonds: ionic, polar covalent, and

In this experiment, the goal is to prepare a Grignard reagent from an unknown aryl halide and identify the identity of the aryl halide by converting it to a carboxylic acid to determine its melting point and molar mass (determined by titration). The experiment began by dissolving 0.25g of magnesium powder in a 25mL round-bottom with 5mL of anhydrous ether and stirring with a stir bar. Then the round-bottom flask was set up for reflux using a Claisen adapter where the vertical part is covered with a septum to prevent air from mixed with the solution. The septum is very important because the Grignard product can react with oxygen to produces a carboxylic acid, which is not wanted. Also, the choice of anhydrous solvent is important because the Grignard product can react with water to produce an alkane. With the reflux set up, the next step was to add the halide. 1.2mL of the unknown bromoarene mixed with 2.5mL ether was slowly added dropwise through the septum using the needle and syringe. The bromoarene had to be added slowly because there Grignard product would undergo another unwanted side reaction by reacting with the unknown bromoarene. The product with be a new carbon-carbon bond between the unknown bromoarene and the Grignard product. If the bromoarene is added slowly, the chances of the Grignard product reacting with the bromoarene over the magnesium is low because magnesium exists in larger concentration in the solution. Once all the unknown bromoarene

Introduction This experiment was undertaken in order to create stilbene dibromide. Bromine is added through electrophilic addition in attacking the double bond. This experiment was also executed to determine the stereochemistry of this addition reaction, whether it created meso products or d,l products. Data and Results Initially, 0.9 grams of stilbene were added to the solution.

In order to isolate benzoic acid, benzocaine and 9-fluorenone, each component needed to be separated from one another. All three compounds began together in one culture tube, dissolved in methylene chloride and formed into a homogenous mixture. In this culture tube, two milliliters of aqueous three molar hydrochloric acid was added, which immediately formed two layers, the top acidic aqueous layer was clear in color and contained benzocaine, and the bottom organic formed was yellow and contained benzoic acid and 9-fluorenone. Benzocaine’s amino group is protonated by the aqueous layer hydronium. This protonation forms the conjugate acid of benzocaine, benzocaine hydrochloride. Thus, the conjugate acid, benzocaine hydrochloride is a salt in which is soluble in water and furthermore can be isolated from the organic mixture. When testing out the pH levels in benzocaine, the pH test strip was dark blue in color, indicating a pH level of around 5 to 7. When isolating benzoic acid, two milliliters of aqueous three molar sodium hydroxide was added, which deprotonates the carboxylic group in benzoic acid, forming its conjugate base, sodium benzoate. As with benzocaine hydrochloride, sodium benzoate is a water soluble ionic salt in the aqueous layer that can then be separated from the bottom organic layer containing the 9-fluorenone. The pH test strip was a vibrant red for benzoic acid, indicating a pH of 2. Now the 9-fluorenone is left, deionized water is added to remove any excess

2. Plan: Each student in a group of three will work to create a reaction with the Benzonitrile Oxide with, cis-stilbene, trans-stilbene, or styrene in an Erlenmyer flask. With this Reaction solution thin layer chromatography will be performed using each reaction solution. The different reactions will then be compared by running co-spot TLC’s. An NMR of the crude products from each reaction will be taken.

Experiment 4A: Determination of a Partition Coefficient for Benzoic Acid in Methylene Chloride and Water, and Experiment 4B: Solvent Extraction I: Acid-Base Extraction Using the System Benzoic Acid, Methylene Chloride, and Sodium Bicarbonate Solution

The halide is introduced to the presence of magnesium to thus produce the grignard reagent. The resulting Mg-R complex results in a partially negatively charged carbon, a strong nucleophile. Since the carbon in the final grignard reagent is a very strong nucleophile, the solvent must be

Abstract: This procedure demonstrates the nitration of methyl benzoate to prepare methyl m-nitrobenzoate. Methyl benzoate was treated with concentrated Nitric and Sulfuric acid to yield methyl m-nitrobenzoate. The product was then isolated and recrystallized using methanol. This reaction is an example of an electrophilic aromatic substitution reaction, in which the nitro group replaces a proton of the aromatic ring. Following recrystallization, melting point and infrared were used to identify and characterize the product of the reaction.

Separately, 20.0 mmol of benzophenone was combined with 10 ml of anhydrous ether. The mixture had a slightly layered appearance. Using a pipette dropper, drops of the benzophenone ether solution were added to the original Grignard reagent solution. Drops were added slowly, contact caused a slightly bubbling.

The objective of this experiment is to synthesize triphenylmethanol using a Grignard reagent. A Grignard reagent is a carbon-magnesium halide, where the carbon acts as a nucleophile. As shown in Mechanism 1, it is formed by reacting an alkyl halide, in this case a bromide (bromobenzene), with magnesium metal in anhydrous ether. During the preparation of the Grignard reaction, another by-product, biphenyl, will be formed; this is caused from the rapid addition of bromobenzene to the Grignard reagent solution. However, the by-product will later be removed with petroleum ether. It is also important to have no traces of water as the Grignard reagent is very reactive with water. A reaction between the Grignard reagent and water will result in an

Recrystallization was done to remove impurities from the sample. The percent recovery of benzoic acid during recrystallization is 23.02%. The difference between the pure and impure samples was observed by comparison of melting points. It was found that impure sample had a lower and wider melting point range of 120.1-122.2 (C). The pure sample melting point range was 121.3-122.5 (C). These ranges helped determine purity by comparing the known melting point of pure benzoic acid.

This experiment involved the synthesis of diphenylmethanal from phenylmagnesium bromide which is a Grignard reagent, and benzaldehyde which is a carbonyl group. The goal of this experiment was to investigate the ability of the Grignard reaction to yield the theoretical predicted product and evaluate its efficiency. The Grignard reaction is an important reaction because of its ability to allow the formation of carbon-carbon bonds. These formations of C-C sigma bonds, then allow for the formation or making of large or complex synthetic molecules from very simple reagents. These complex molecules are then used in many different areas such as the pharmaceutical industry. Also, one must note that Grignard reagents are strong nucleophiles that can attack carbonyl groups that can form substituted alcohols after the protonation step.

 Carboxylic acids are substances that have a general formula of RCO2H. They are considered as Bronsted-Lowry acids or proton donors. They are polar since they can be both be hydrogen-bond acceptor and donors due to the presence of the carbonyl and hydroxyl groups respectively. There are instances that the hydroxyl and carbonyl group have the tendency to self-associate and become less soluble if the carbon no increases.