Lab 1 Nitration Of Naphthalene

The following equations and calculations are necessary in order to assess the results of the experiment. Calculation 1 utilizes Eq.1 to determine the mass and actual yield of triphenylmethanol on a watch glass. In all of the following calculations, “LR” refers to benzophenone, the limiting reagent of the experiment, and “Product” refers to triphenylmethanol.

The mixture was transferred to an ice bath to crystallize the product, after which the product was collected by vacuum filtration on a Hirsch funnel, washing the flask with small aliquots of cold xylene and pouring the solution over the crystals, allowing the vacuum to thoroughly dry the product. Additional drying was achieved by transferring the product to filter paper and pressing the crystals to remove any excess moisture. The product was then weighed and a melting point determined. A comparative TLC was run in Hexanes:Ethyl Acetate solvent against maleic anhydride to verify the purity of the

From this point in the lab, we could make no real predictions about the composition of the products or the mechanisms of the reactions. This is also most likely the reason for such a low yield and strange coloration. Other sources of error include poor transfer of the crude product from filter paper to flask for recrystallization, as some of the product was lost in the transfer, lessening the yield. Also, when the 0.75 mL of the 16 M nitric acid was added, the pH, instead of becoming neutral, resulted in a pH of 1, in effect “burning” the product. This may also be a reason for the color of the final product.

With a molecular weight of 180.2 grams/mole, this is equivalent to 0.00499 moles initially. 0.941 grams of the product, stilbene dibromide was collected upon completion of the experiment. With a molecular weight of 340.0 grams/mole, this amounted to 0.00277 moles of product. This gives a percent yield of 55.5%. The melting point of the product was found to be between 250C and

Nitric acid, HNO3, dissociates in water to form nitrate ions and hydronium ions. What change in hybridization of the nitrogen atom occurs in this dissociation?

Nitric acid has the chemical formula HNO3, a molecular weight of 63.01 grams/mol, a melting point of -42 °C, and a density of 1.5027 grams/mL. (PubChem.com)

Dane, John, and Kent J. Voorhees. "Investigation of Nitro-Organic Compounds in Diesel Engine Exhaust." National Renewable Energy Laboratory (2010). Print.

1. 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.

Tube 4 now should only have crude solid in the tube and it is then weighed. The tube is placed into a 50℃ water bath and then approximately 0.5 -1 ml of methanol is added, as well as H2O until the solution gets cloudy, once the solution is dissolved it is cooled to room temperature and then iced. The crystals are then collected using a Hirsh funnel. Next a small amount (~ 0.1g) of the crystals are placed into a melting point tube and placed into the melting point machine to record the unknown neutral substances melting point.

Results: No substantial qualitative data was collected, except that the original reaction mixture turned a purple color. Upon the addition of anise oil and heat, the reaction mixture turned a brown color. And with the addition of NaHSO3 the mixture turned a white color. The mass of the final product sample was measured to be 0.08g (see Calculation 1). The melting point range for this sample was 172.8-185.4ºC in Trial 1 and 171.6-185.2ºC in Trial 2 (see Table 1). The IR spectrum of anise oil can be found attached. Peaks appear to exist at 3022.86, 3002.41, 2957.58, 2933.88, 2912.63, 2834.94, and 2723.19 (cm-1). Another set of peaks appear to exist at 1608.06, 1510.55, 1464.73, 1441.16, 1306.3, 1283.06, 1247.18, 1174.78, 1036.26, 964.58, 839.29, and 787.03 (cm-1). No other significant quantitative results were collected.

The theoretical value of the combustion of solid naphthalene was calculated by substituting their given values in the literature into equation (5) in place of their corresponding terms.

Aromatic compounds can undergo electrophilic substitution reactions. In these reactions, the aromatic ring acts as a nucleophile (an electron pair donor) and reacts with an electrophilic reagent (an electron pair acceptor) resulting in the replacement of a hydrogen on the aromatic ring with the electrophile. Due to the fact that the conjugated 6π-electron system of the aromatic ring is so stable, the carbocation intermediate loses a proton to sustain the aromatic ring rather than reacting with a nucleophile. Ring substituents strongly influence the rate and position of electrophilic attack. Electron-donating groups on the benzene ring speed up the substitution process by stabilizing the carbocation intermediate. Electron-withdrawing groups, however, slow down the aromatic substitution because formation of the carbocation intermediate is more difficult. The electron-withdrawing group withdraws electron density from a species that is already positively charged making it very electron deficient. Therefore, electron-donating groups are considered to be “activating” and electron-withdrawing groups are “deactivating”. Activating substituents direct incoming groups to either the “ortho” or “para” positions. Deactivating substituents, with the exception of the halogens, direct incoming groups to the “meta” position. The experiment described above was an example of a specific electrophilic aromatic

The product attained was a white, dry solid. The small amount of product lost during the second recrystallization was most likely do to impurities, which were filtered away with the methanol. Impurities that contributed to the low percent yield could be due to side reactions such as methyl o-nitrobenzoate and methyl p-nitrobenzoate. Although the percent yield attained was low, the product attained was fairly pure due to similarity in melting point and IR spectrum compared to standardly accepted values for methyl m-nitrobenzoate.

2-naphthol has a molecular weight of 144.17 g/mol, with a density of 1.22 g/cm3. The melting point of 2-naphthol is in the range of 121 to 123 °C. The stock solution of 2-naphthol has a concentration of 1.9844E-3 M.

An ice bath was prepared in a large beaker and a small cotton ball was obtained. 0.5 g of acetanilide, 0.9 g of NaBr, 3mL of ethanol and 2.5 mL acetic acid was measured and gathered into 50mL beakers. In a fume hood, the measured amounts of acetanilide, NaBr, ethanol and acetic acid were mixed in a 25mL Erlenmeyer flask with a stir bar. The flask was plugged with the cotton ball and placed in an ice bath on top of a stir plate. The stir feature was turned on a medium speed. 7mL of bleach was obtained and was slowly added to the stirring flask in the ice bath. Once all the bleach was added, stirring continued for another 2 minutes and then the flask was removed from the ice bath and left to warm up to room temperature. 0.8mL of saturated sodium thiosulfate solution and 0.5mL of NaOH solution were collected in small beakers. The two solutions were added to the flask at room temperature. The flask was gently stirred. Vacuum filtration was used to remove the crude product. The product was weighed and a melting point was taken. The crude product was placed into a clean 25mL Erlenmeyer flask. A large beaker with 50/50 ethanol/water