Data And Report Submission - Nucleophilic Aromatic Substitution (2pts) Nucleophilic Aromatic Substitution Are you completing this experiment online? Data Collection Amount of reactant used in gram (a) Product obtained in grams () (24pts) Calculations and Analysis 0.070 0.009 (Sota) Amount of reactant in moles (5pts) Product obtained in moles (51) Product theoretical (ots) Product theoretical yield (5pts) Product percent yield Write the equation for the reaction Normal IP (25pts) Post Lab Questions (10pts) 1. Look up the expected melting points for reactants and products B Til Normal 3 BIU (15) 2. Will measuring the melting point of your product tell you that your product is relatively pure? Explain your answer Lab 7 Nucleophilic Aromatic Substitution Objectives • Perform the reaction of 3,4-dichloro-1-nitrobenzene with sodit methoxide • Identify the product of 3,4-dichloro-l-nitrobenzene and sodium methoxide Background Nucleophilic Aromatic Substitution Aromatic compounds are often thought of as being too stable to react, but aromatic rings can undergo substitution reactions. The most common aromatic reaction is the clectrophilic aromatic substitution, in which electrons from the ring attack an electrophile, creating a new substituent However, nucleophilic substitution is also possible for aromatic compounds under the right conditions Overall Mechanism of the Reaction The general reaction of nucleophilic aromatic substitution involves the replacement of a leaving group with a nucleophile, as shown in Figure 1. The nuclovphile attacks at the carbon with the leaving group and leads to a carbonion intermediate. Therefore, the reaction requires a strong nucleophile and a good leaving group on the ring. The aromatic ring is then reestablished as the clectrons rearrange and kick off the leaving group EWO EWG EWG EWG EWG EWG LG LG Nu LG Nu Figure 1 General mechanism of nucleophilic aromatic substitution including a nucleophile (Nu) attacking a ring with a leaving group (LG) and electron withdrawing group (EWG) attached Impact of the Substituents on the Ring There are two important substituents on the aromatic ring for the reaction to succeed. First, there needs to be a substituent on the ring that can act as a leaving group. Halides are commonly used for this purpose. In addition to being good leaving groups, they also increase reactivity between the aromatic ring and the nucleophilc by making the attached carbon have more of a partial positive charge. For a successful substitution, there needs to be a good leaving group in the position where the nucleophile will end up The other important substituent on the ring is at least one strong electron withdrawing group, such as a nitro group. The electron withdrawing ability helps stabilize the carbonion intermediate of the roaction. Thus, increasing the number of electron withdrawing groups generally increases the rate . 3,4-dichloro-1-nitrobenzene • Anhydrous magnesium sulfate Methanol Microscale glassware kit 25% sodium methoxide in methanol • Boiling chips Dichloromethane • Melting point apparatus Safety goggles are required! All work should be performed in the fume hood. 3,4-dichloronitrobenzene is a toxic irritant. Sodium methoxide is flammable and corrosive. Methanol is flammable and toxic. Dichloromethane is a toxic irritant. Magnesium sulfate is an irritant.