Luminol can be prepared from 3-nitrophthalic acid by treatment with hydrazine followed by reduction of the first product by sodium dithionite.
Luminol is a chemiluminescent compound. Luminol also exhibits properties that very closely resemble the chemiluminescent compound that fireflies produce to emit their non-thermal, luminescent light (McElroy, Seliger, White 1969, p.153-170).
The purpose of this experiment was to prepare luminol and then observe its chemiluminescent properties by adding luminol to dimethylsulfoxide and sodium hydroxide. (Stanley and others 1934, p.142)
Materials and Methods
The first step in the procedure was to place a flask containing 15mL water on a hot plate with sand surrounding until water was hot. While the water was being heated, 1.0g 3-nitrophthalic acid and 2mL of 5% aqueous solution of hydrazine was added to a 200mm x 150mm test tube. This mixture was heated until all solute dissolved into the solution. After solute had dissolved, 3.0mL triethylene glycol was added to the test tube. The tube was then clamped over a burner with a thermometer inserted. The solution was vigorously boiled to distill excess water. The temperature was allowed to rise to 215°C. Once the solution had reached the desired temperature, a temperature between 215°C and 220°C was maintained for two minutes. When the two minutes expired, the burner was removed and the solution was allowed to cool to 100°C. The 15mL of hot water was then added to the solution. The precipitated 3-nitropthalhydrazide formed was collected by suction filtration. The collected, damp compound was transferred to the same test tube in which it was prepared. This test tube was not cleaned before the content transfer. 5mL of 10% sodium hydroxide was added to this test tube. The mixture was then stirred to dissolve all solute. Once the solute had dissolved, 3.5g of an 85% technical sodium dithionite was added to the solution. The mixture was then heated to its...
References: Mcelroy, W. D., H. H. Seliger, and E. H.White.1969. "mechanism of bioluminescence, chemi‐luminescence and enzyme function in the oxidation of firefly luciferin*,†." photochemistry and photobiology 10.3: 153-170.
Ernest H. Huntress , Lester N. Stanley and Almon S. Parker 1934. "The oxidation of 3-aminophthalhydrazide (" luminol") as a lecture demonstration of chemiluminescence." Journal of Chemical Education 11, no. 3:142.
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