The Grignard reaction is a robust organic synthesis method for creating carbon-carbon bonds. One application of Grignard reagents is their use in activating nitrous oxide, a compound initially thought to be inert towards Grignard reagents—Tskhovrebov, et al. show that primary and secondary aliphatic Grignard reagents readily react with nitrous oxide to form hydrazones.1 Grignard reagents can also be used in cross-coupling reactions (iron) involving alkenyls/aryl carboxylates to create good carboxylate electrophiles, as elucidated by Li, et al.2 Figure 1: Preparation of Grignard Reagent (Phenylmagnesium Bromide) In this experiment, a Grignard reagent was prepared using bromobenzene and magnesium in diethyl ether (Figure 1). An aprotic solvent (diethyl ether) was used because Mg0 reacts readily with protic solvents to form Mg2+. Figure 2: Formation of 1,1-Diphenylethanol with Grignard Reagent Afterwards, the Grignard reagent was added to acetophenone to form 1,1-diphenylethanol. Ammonium chloride was added to protonate the oxyanion (acid workup). Results and Discussion Figure 3: Grignard Reaction Mechanism …show more content…
First, the reaction was conducted using clean, dry glassware in an inert atmosphere (anhydrous ether) to minimize side reactions involving the Grignard reagent. In particular, water can react with the Grignard reagent (very basic) to form benzene and magnesium hydroxide bromide: C6H5MgBr + H2O → C6H5 + MgOHBr. We also added acetophenone to the Grignard reagent dropwise because the reaction was very exothermic; a noticeable amount heat was produced (Figure 3). After forming 1,1-diphenylethanol, we washed the crude sample (1,1-diphenylethanol with impurities) with cold hexane to remove impurities such as acetophenone and bromobenzene. Cold hexane was added (rather than ambient temperature hexane) to minimize 1,1-diphenylethanol
Wittig reactions allow the generation of an alkene from the reaction between an aldehyde/ketone and an alkyl halide (derived from phosphonium salt).The mechanism for the synthesis of trans-9-(2-phenylethenyl) anthracene first requires the formation of the phosphonium salt by the addition of triphenylphosphine and alkyl halide. The phosphonium halide is produced through the nucleophilic substitution of 1° and 2° alkyl halides and triphenylphosphine (the nucleophile and weak base). An example is benzyltriphenylphosphonium chloride, which was used in this experiment. The second step in the formation of the of the Wittig reagent, which is primarily called a ylide and derived from a phosphonium halide. In the formation of the ylide, the phosphonium ion in benzyltriphenylphosphonium chloride is deprotonated by the base, sodium hydroxide to produce the ylide as shown in equation 1.
The goal of this lab is to exemplify a standard method for making alkyne groups in two main steps: adding bromine to alkene groups, and followed by heating the product with a strong base to eliminate H and Br from C. Then, in order to purify the product obtained, recrystallization method is used with ethanol and water. Lastly, the melting point and IR spectrum are used to determine the purity of diphenylacetylene.
Abstract In this experiment methyl-3-phenyl-2-propenoate was prepared using a Wittig reaction. Benzaldehyde and methyl (triphenylphosphoranylidene) acetate were used to give a final product. 0.33g of methyl3-phenyl-2-propenoate was found at the end of the experiment therefore the percentage yield of methy-3-phenyl-2-propenoate is 62%. The Rf value of benzaldehyde was found to be 0.85.
Scheme 1: Fischer Esterification reaction between benzaldehyde and ethanol to produce benzocaine. INTRODUCTION:
The formation of quinone is especially enticing, as it is more stable to the photooxidation, comparing to acenes. Anthraquinone can be easily reduced to the target molecule or it can be functionalized in the exact position which is especially important for the tetracenes
Ishaan Sangwan Experiment 7: Grignard Reaction Discussion In this experiment, a Grignard reaction was performed to create a carbon-carbon bond, between a bromide and carbon dioxide. The product was then protonated to form a carboxylic acid, which was identified by obtaining its melting point, and by performing a titration with NaOH to obtain its molecular weight. In organometallic chemistry, carbon is bound to a metal.
In this two week project, an experiment was designed and tested. The experiment was performed to tested how a variable affects the E/Z ratio products of a Wittig reaction.
The Examination of Chemical Reactions in Multiple Chemical Compounds to Identify Types of Energy Changes and Types of Reactions The purpose of this lab is to investigate chemical reactions that takes place between different chemical compounds. The products formed through these reactions will be observed for physical properties and chemical changes. Pour 100 mL of citric acid into an Erlenmeyer flask. Fill a clay crucible with baking soda.
Then the reaction tube was capped but not tightly. The tube then was placed in a sand bath reflux to heat it until a brown color was formed. Then the tube was taken out of the sand bath and allowed to cool to room temperature. Then the tube was shaken until a formation of a white solid at the bottom of the tube. After formation of the white solid, diphenyl ether (2 mL) was added to the solution and heated until the white solid was completely dissolved in the solution. After heating, the tube was cooled to room temperature. Then toluene (2 mL) was added to the solution. The tube was then placed in an ice bath. Then the solution was filtered via vacuum filtration, and there was a formation of a white solid. Then the product was dried and weighed. The Final product was hexaphenylbenzene (0.094 g, 0.176 mmol,
Enantiomers, a type of isomer, are non-superimposable, mirror images of each other. Diasteriomers, another type of isomer, are non-superimposable, non-mirror images of each other. Dimethyl maleate and dimethyl fumarate are diasteriomers, as they are not mirror images but instead vary in the orientation of the carbomethoxy groups around the double bond. Dimethyl maleate is the cis-isomer because both groups are on the same side and dimethyl fumarate is the trans-isomer because the two groups are on opposite sides. A bromine free radical mechanism was required for this conversion. First, energy from light is required to create two bromine free radicals from Br2. Then one of the free radicals attacks the double bond in dimethyl maleate, breaking it and creating a carbon radical on the other carbon. The bond then rotates and reforms, freeing the bromine radical and creating the trans-isomer, dimethyl fumarate. Bromine in this reaction is acting as a catalyst in this reaction and then cyclohexane is added at the end to neutralize the bromine free radicals. The activation reaction of the radical reaction is lower than the activation energy of the addition reaction, which is why it occurred more quickly. This reaction was successful because the percent yield was 67.1%, which is greater that 65%. It also demonstrated the expected principles, as the reaction did not occur without the presence of both light and bromine. The dimethyl fumarate had a measured boiling point of 100C to 103C, which is extremely close to the expected boiling point of 102C to
Discussion: In the experiment of enzyme kinetics, inhibition and concentration of substrate were investigated. The effect of these two factors will be determined through an experiment of four different concentrations of the inhibitor, and five different concentrations of substrate. Figures 2, 3, 4, and 5 provide an observation for the change in absorbance with time in the presence of different concentrations of inhibitor, and in the absence of inhibitor (phosphate).
As they are organic, any reactions? they partake in are usually quite slow and therefore must be heated under reflux. It is a snort. A reaction carried out under reflux is one in which a condenser is positioned vertically in the neck of the reaction flask to prevent any of the solvent/reactant liquids from evaporating. Halogenoalkanes do not mix with water, so must be dissolved in ethanol before use.
Benzyl bromide, an unknown nucleophile and sodium hydroxide was synthesized to form a benzyl ether product. This product was purified and analyzed to find the unknown in the compound. A condenser and heat reflux was used to prevent reagents from escaping. Then the solid product was vacuum filtered.
Thickett, Geoffrey. Chemistry 2: HSC course. N/A ed. Vol. 1. Milton: John Wiley & Sons Australia, 2006. 94-108. 1 vols. Print.
In homogeneous catalysis, oxidation of alcohols to corresponding aldehyde and ketone requires a stoichiometric amount of oxidant such as chromium(VI), permanganate, DMSO and DDQ (Cardona and Permeggiani, 2015). Consequently, all of these oxidants suffer drawbacks of generating high amounts of organic and inorganic toxic side products after the reaction. Furthermore, these methods are usually carried