Reaction Intermediates in Organic Chemistry
Description A set of four Petri dishes are filled with a mixture of 7,7,8,8, tetracyanoquinodimethane (TCNQ) in Diglyme are placed on an overhead projector table and warmed with the lamp. Portions of Morpholine in Diglyme are added to the four petri dishes. The color of the solution in the dishes is dependent on the species in the liquid. The dye itself is pale yellow, the first product, the TCNQ anion radical is green, and the first substitution product is dark blue. The third species the second Substitution product, is generated by step addition of morpholine to the final petri dish, yielding a bright golden color.
Source: Novaki, L.P., Brotero,P. P., El Seoud, O. A., Journ. Chem Educ. (1989) Vol 66 No. 12 pp.1040-1041
Year: 1989 Vol: 66, No.12 Page: 104o – 1041
Keywords: EAS, Intermediate, Substitution, Organic Chemistry, Aromaticity, Conjugation, Delocalization
Rating: 
Hazard: Medium
- Cyanide by-product
- Acute toxicity hazard – oral, dermal, inhalation
- Aquatic toxicity hazard
- Skin corrosion hazard
- Serious eye damage hazard
- Flammability hazard
- Reproductive toxicity hazard
- Electric shock hazard
Effectiveness: Average
- Good connection from demo to course material
- Results are observable without guidance
- Time to results is high
- Moderate reliability
- Contrast between systems behavior is clear
Difficulty: High
- Prior training required
- Handling of organic chemicals
- Multi-step procedure with varying results
- Requires precise temperature control
Safety Precautions:
- Eye Protection Required
- Gloves Required
- Lab coat required
- Face shield recommended
- Avoid exposure to dust, vapors, liquids, or mists
- Prepare agents in a working fume hood
- Absorbent materials on hand
- Sodium hydroxide or sodium hypochlorite on hand
- Perform in a well-ventilated area
- Use of UL-approved three-prong plug and outlet
Class: Organic Chemistry, Reaction Mechanisms
Division: General, Organic Chemistry
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