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 melting point of the final product, diphenylacetylene, was found to be 65-68 degrees Celsius which is right around the ideal 61 degrees Celsius melting point; this shows that purification during the lab worked and that the sample was almost 100% pure. Since only 0.01g of diphenylacetylene was collected and the theoretical yield was calculated to be 0.049g, this experiment had a 20.41% yield. A few sources of error that explain the low percentage could be the loss of crystals when transferred from the test tube to the suction apparatus or when they were transferred from the suction apparatus to the filter paper to be dried and then weighed. Crystals could have also been lost if more than 5 drops of methanol was added because excess methanol would dissolve the crystals. The experiment was successful when looking at the crystals collected from the addition step and the elimination step; however, to improve the percent yield and collected product the the test tubes could have been allowed to cool down in the ice bath past the 5 minutes to ensure all the crystals formed

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.

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.

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.

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

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?

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

Figure 1. Reaction mechanism for the reduction of cyclohexanone to adipic acid, using the oxidizing agent nitric acid.

The purpose of this experiment is to separate a mixture of salicylic acid and naphthalene using extraction, recrystallization and sublimation techniques. Extraction is the separation of compounds from a mixture based on their relative solubilities in different solvents. Sublimation is the process of separation by which a substance transitions from the solid phase into the gas phase, skipping the liquid phase. Recrystallization involves dissolving a substance in an appropriate solvent then crystallizing it as it cools (impurities remain in solution). The melting points of the substances were determined in order to assess their purity and the percent recovery of pure naphthalene and salicylic acid were calculated. According to the results, the melting point of pure naphthalene was between 86°C -89°C range, whereas for pure salicylic acid was 167°C -170°C. Both determined melting points were higher compared to the literature value of 80.26°C and 158.6°C for pure naphthalene and salicylic acid respectively. Lastly, the percent recovery for pure naphthalene and salicylic acid were 17.7% and 71.2% accordingly.

A pre-weighed (0.315g) mixture of Carboxylic acid, a phenol, and neutral substance was placed into a reaction tube (tube 1). tert-Butyl methyl ether (2ml) was added to the tube and the solid mixture was dissolved. Next, 1 ml of saturated NaHCO3 solution was added to the tube and the contents were mixed separating the contents into three layers. Once this was completed

The objectives of this lab are, as follows; to understand what occurs at the molecular level when a substance melts; to understand the primary purpose of melting point data; to demonstrate the technique for obtaining the melting point of an organic substance; and to explain the effect of impurities on the melting point of a substance. Through the experimentation of three substances, tetracosane, 1-tetradecanol and a mixture of the two, observations can be made in reference to melting point concerning polarity, molecular weight and purity of the substance. When comparing the two substances, it is evident that heavy molecule weight of tetracosane allowed