2-(2,4-Dinitrobenzyl) Pyridine
2-(2,4-Dinitrobenzyl) pyridine
Peter Defnet and Cody Krepps
Department of Chemstry
Juniata College
Huntingdon, PA
September 18, 2012
Abstract: Nitration of 2-benzylpyridine is supposed to yield 2-(2,4-Dinitrobenzyl) pyridine, when electrophilic aromatic substitution is the mechanism. Experiencing many pitfalls, however, has lead to the actual product obtained to contain the expected product, as well as many impurities. This report examines the supposed mechanism for the electrophilic substitution, a mechanism for the product’s photochromic property, as well as an explanation as to why the mechanism happens in this particular sequence.
Introduction:
Nitration of 2-benzylpyridine through electrophilic aromatic substitution (EAS) is expected to yield 2-(2,4-Dinitrobenzyl) pyridine, a photochromic product. This reaction was first discovered by Tshitschibabin in 19253, and is frequently used today for a variety of purposes, including use with photo recording media4. Being photochromic means that when exposed to UV light, or when exposed to darkness, the color of the compound changes in response to the presence or absence light. The mechanism for the creation of 2-(2,4-Dinitrobenzyl) pyridine from 2-benzylpyridine, is a basic form of EAS, and is shown in Figure 1, below.
Mechanism…EAS…
Results and Discussion:
Concentrated sulfuric acid was obtained and placed in a round bottom flask, which was placed in an ice bath. A stir bar was added to the solution and the ice bath was placed on a combo plate to induce the stirring mechanism. While stirring, 2-benzylpyridine and 70% nitric acid were added dropwise to the cold sulfuric acid. The solution was observed to be a yellow color. The flask was then placed on an already hot heating mantle, which immediately changed the color of the solution from yellow to a dark brown color. The mantle then had changed electrical sockets and was plugged into a variac with a range of 35-40, in attempt to cool the
Peter Defnet and Cody Krepps
Department of Chemstry
Juniata College
Huntingdon, PA
September 18, 2012
Abstract: Nitration of 2-benzylpyridine is supposed to yield 2-(2,4-Dinitrobenzyl) pyridine, when electrophilic aromatic substitution is the mechanism. Experiencing many pitfalls, however, has lead to the actual product obtained to contain the expected product, as well as many impurities. This report examines the supposed mechanism for the electrophilic substitution, a mechanism for the product’s photochromic property, as well as an explanation as to why the mechanism happens in this particular sequence.
Introduction:
Nitration of 2-benzylpyridine through electrophilic aromatic substitution (EAS) is expected to yield 2-(2,4-Dinitrobenzyl) pyridine, a photochromic product. This reaction was first discovered by Tshitschibabin in 19253, and is frequently used today for a variety of purposes, including use with photo recording media4. Being photochromic means that when exposed to UV light, or when exposed to darkness, the color of the compound changes in response to the presence or absence light. The mechanism for the creation of 2-(2,4-Dinitrobenzyl) pyridine from 2-benzylpyridine, is a basic form of EAS, and is shown in Figure 1, below.
Mechanism…EAS…
Results and Discussion:
Concentrated sulfuric acid was obtained and placed in a round bottom flask, which was placed in an ice bath. A stir bar was added to the solution and the ice bath was placed on a combo plate to induce the stirring mechanism. While stirring, 2-benzylpyridine and 70% nitric acid were added dropwise to the cold sulfuric acid. The solution was observed to be a yellow color. The flask was then placed on an already hot heating mantle, which immediately changed the color of the solution from yellow to a dark brown color. The mantle then had changed electrical sockets and was plugged into a variac with a range of 35-40, in attempt to cool the
References: 1. Ault, A. Cardon, J. Liberko, C. Pionek, A. Cornellcollege.edu. http://people.cornellcollege.edu/cliberko/orglab.htm. (9/16/12), Organic Chemistry Laboratory CHE 327 2. Journal of Chemical Education 2001, 78, 1596 3. Minard, R. Shierhorn, M. psu.edu. http://courses.chem.psu.edu/chem36/Chem36H/IndivExpt1/440%20Photochromic%20Compound.pdf. (9/16/12), 2-(2,4-dinitrophenyl)pyridine: The Synthesis of a Photochromic Compound. 4. SureChem.org. http://www.surechem.org/index.php?Action=document&docId=89083&db=EPA&tab=desc&lang=EN&db_query=4%3A2%3A0%3A%3A4%3A2%3A0%3A%3A4%3A2%3A0%3A&markupType=all. (9/16/12), Photo-recording media and photo-recording method.