In Experiment 13B we generated a Grignard reagent using bromobenzene (the limiting reagent) and magnesium in an ether solvent. This Grignard reagent was then reacted with benzophenone, followed by an acidic workup, to produce triphenylmethanol. The ether solvent was used in this experiment because is helped to stabilize the Grignard reagent by coordinating its lone pair electrons, therefore donating electron density to a electron deficient magnesium molecule. Anhydrous conditions were required because the Grignard reagent is a reactive nucleophile and a strong base. The anhydrous conditions prevent the Grignard reagent from deprotonating water to form benzene. We ensured anhydrous conditions by flame drying all of our glassware. The reaction began with the insertion of magnesium into the carbon-bromine bond to generate the Grignard reagent. 96 mg of magnesium turnings were ground up with a mortar and pestle in order to remove any surface oxides and contaminations that may preclude magnesium’s ability to react with unreactive alkyl halides. The magnesium turnings, along with a small crystal of iodine and a drop of 1,2-dibromoethane were added to a round bottom flask. The 1,2-dibromoethane is necessary to activate the alkyl halide. In a conical vial 2mL of anhydrous ether …show more content…
The remaining organic layer was washed with sodium bisulfite and brine. The sodium bisulfite was used to wash away MgOH and neutralize the acid. The solution was dried using anhydrous sodium sulfate and heated until the solvent evaporated. Anhydrous sodium sulfate is a drying agent used to remove water from the mixture. The crude mixture was triturated in petroleum ether. Trituration broke down the crude mixture into a desirable compound that remained insoluble, and impurities, which were soluble in the liquid. Therefore, the impurities were filtered out using petroleum ether. This rinsed away the non-polar byproduct,
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.
In this lab we used the greener approach, which involves the addition of bromine across a double bond. When bromine reacts with E-stilbene (trans-1,2-diphenylethene), two new chiral carbons are created from the sp2 carbons, therefore 3 different dibrominated stereoisomers are possible: meso-(1R,2S), or the raceminc mixture-(1R,2R) or (1S,2S)-dibromo-1,2-diphenylethane (Gilbert, 2010). When the bromination ion intermediate proceeds through a stereospecific mechanism, then the meso dibromide is formed exclusively. The racemic dibromides are formed from the concerted syn addition if the mechanism proceeds
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
6. Purpose: to clarify the mechanism for the cycloaddition reaction between benzonitrile oxide and an alkene, and to test the regiochemistry of the reaction between benzonitrile oxide and styrene; to purify the crude product of either trans-stilbene, cis-stilbene, or styrene reaction.
The next day an orange goopy textured product resulted. The extracts were then dried and combined with anhydrous sodium sulfate, then evaporated with dry air under the hood in a warm water bath. The liquid was cooled and had an initial weighing of 0.5887g. It was reweighed several minutes later with a final
Organometallic compounds are compounds that contain carbon-metal bonds (C-M bonds), in which carbon bears a partial negative charge because metal is less electronegative than the carbon. This partial negative charge of the carbon atom allows it to be a good nucleophile that attacks the electrophile to make a new carbon-carbon bond. There are several examples of organometallic compounds, such as organolithium, Gilman reagents, and Grignard reagents (organomagnesium reagent). In this experiment, Grignard reagents are prepared and reacted with other electrophilic carbon to form a new carbon-carbon bond. Victor Grignard discovered Grignard reagent around 1890s and received a Noble Prize in 1912 with his discoveries. In this experiment, an alkyl halide or aryl halide is reacted with magnesium metal to prepare a Grignard reagent (R-MgX). In this Grignard reagent preparation reaction, halide is typically used with bromine (sometimes with chlorine, not
Wash (swirl and shake) the organic layer with one 10-mL portion of water and again drain the lower aqueous layer. Transfer the organic layer to a small, dry Erlenmeyer flask by pouring it from the top of the separatory funnel. Dry the crude t-pentyl chloride over 1.01 g of anhydrous calcium chloride until it is clear (see Technique 12, Section 12.9). Swirl the alkyl halide with the drying agent to aid the drying.
In a 25-mL round-bottom flask, 1-chlorobutane (5 mL, 4.32 g, 0.046 mol), sulfuryl chloride (1.6 mL, 2.7 g, 0.02 mol), 2,2’-azobis-(2-methylpropionitrile) (0.03 g), and a boiling chip were added. After a condenser and gas trap were attached to the flask, the mixture was heated to a gentle reflux in a steam bath for 20 min. The flask was then allowed to cool down quickly in an ice bath for a short time before a second portion of the 2,2’-azobis-(2-methylpropionitrile) (0.03 g) was added to the flask. The mixture was refluxed for another 10 min. before the flask was cooled in a beaker of water. The reaction mixture was then poured into a small separatory funnel already filled with water (10 mL),
Initially, the entire impure product was mixed with diethyl ether for extraction. Upon mixing, the solution separates into two layers; an organic layer and an aqueous layer. The organic layer contains the desired product. Additional extractions using sodium carbonate solution and sodium hydroxide solution were used as well to ensure removal of undesired molecules. The reason that two layers form is due to the fact that water is immiscible with organic products and diethyl ether meaning that they do not dissolve into one another.
In the first reaction, trans-stilbene was brominated to give meso-stilbene dibromide. In the second reaction, the stilbene dibromide was heated with base to induce dehydrobromination (net loss of HBr) and formation of diphenylacetylene. The purpose of this lab experiment is to carry out the bromination of E-stilbene and characterize the product, meso-stilbene dibromide, by its melting point. In the following experiment, the dibromide is converted into diphenylacetylene. Pyridinium hydrobromide perbromide (PHPB), a crystalline solid which is much less corrosive and easier to handle than liquid bromine was the brominating agent used in this
Organometallic compounds are compounds that contain carbon-metal bonds (C-M bonds), in which carbon bears a partial negative charge because metal is less electronegative than the carbon. This partial negative charge of the carbon atom allows it to be a good nucleophile that attacks the electrophile to make a new carbon-carbon bond. There are several examples of organometallic compounds, such as organolithium, Gilman reagents, and Grignard reagents (organomagnesium reagent). In this experiment, Grignard reagents are prepared and reacted with other electrophilic carbon to form a new carbon-carbon bond. Victor Grignard discovered Grignard reagent around 1890s and received a Noble Prize in 1912 with his discoveries. In this experiment, an alkyl halide or aryl halide is reacted with magnesium metal to prepare a Grignard reagent (R-MgX). In this Grignard reagent preparation reaction, halide is typically used with bromine (sometimes with chlorine, not
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
The purpose of this lab was to synthesize triphenylmethanol from benzophenone and bromobenzene by the formation of a Grignard compound with the reagents bromobenzene and magnesium metal. The bromobenzene was first transformed into the Grignard compound and was then reacted with the benzophenone to make the final product. The mixture was then mixed with sulfuric acid and the organic layer was extracted via a separatory funnel. The mixture was then recrystallized from methanol and was allowed to dry and the percent yield, melting point, and the IR was obtained. The mass of the product obtained was 5.45 grams and the percentage yield was determined to be 41.95%. The melting point range obtained from the final product was 89-91°C
Grignard was the child of a sail producer. In the wake of concentrating on arithmetic at Lyon he exchanged to science and found the manufactured response bearing his name (the Grignard response) in 1900. He turned into an educator at the University of Nancy in 1910 and was granted the Nobel Prize in Chemistry in 1912. Amid World War I, he studied chemical warfare agents, especially the produce of phosgene and the identification of mustard gas. His partner on the German side was another Nobel Prize–winning chemist, Fritz Haber. (2) The Grignard reagent is exceptionally responsive and responds with most natural mixes. It likewise responds with water, carbon dioxide and oxygen. (2) Grignard reagents are set up by the response of magnesium metal with fitting alkyl halide in ether dissolvable. The halogen might be Cl, Br, or I. A standout amongst the most imperative employments of the Grignard Reagent is the response with aldehydes and ketones to frame liquor. A related blend utilizes ethylene oxide to plan alcohols containing two more carbon molecules than that of the alkyl halide. (2)