Experiment #9- CHEM 2212

.docx

School

University Of Georgia *

*We aren’t endorsed by this school

Course

2212

Subject

Chemistry

Date

Feb 20, 2024

Type

docx

Pages

Uploaded by HighnessGoldfinch2521

I. Introduction The aldol condensation is a base catalyzed coupling reaction. It couples two carbonyl compounds, usually ketones or aldehydes. The reaction can occur between two of the same carbonyl compounds or two different carbonyl compounds. A catalytic amount of base is sued in the reaction to abstract an alpha carbanion. The carbanion is stabilized via resonance with the adjacent carbonyl. This creates an enolate intermediate. The second step of this reaction involves the enolate species reacting with a second equivalent of the material reacting with the propanol starting material. The alpha carbanion undergoes nucleophilic addition the electrophilic carbonyl of the aldehyde. The reaction is neutralized with water in order to protonate the alkoxide intermediate forming a beta hydroxy aldehyde. The final compound has both an alcohol and carbonyl group. In this experiment particularly only one carbonyl has alpha hydrogens and so acetone will be the only nucleophile for this reaction. The final product obtained will be the dehydrated product due to the stability of the conjugated system. II. Balanced Equation III. Reaction Mechanism H O H OH H O H O H O + O H O O H OH H O OH H OH H O IV. Table of Reagents

Reagent Structure Molecul ar weight Boiling point or meltin g point Densi ty Acetone O Acetone 58.08 g/mol BP: 56 0.791 g/mL p-Tolualdehyde O p-Tolualdehyde 120.15 g/mol BP:205 1.019 g/mL o-Tolualdehyde O o-Tolualdehyde 120.15 g.mol BP:200 1.039 g/mL 4- Methoxybenzalde hyde O O 4-Methoxybenzaldehyde 136.15 g/mol BP:248 1.12 g/mL Benzaldehyde O Benzaldehyde 106.12 g/mol BP: 178.1 1.04 g/mL Ethanol OH Ethanol 46.068 g/mol BP:78. 37 0.79 g/mL Sodium hydroxide Na + OH - Sodium hydroxide 39.997 g/mol MP: 318 (1E,4E)-1,5- diphenylpenta-1,4- dien-3-one O (1E,4E)-1,5-diphenylpenta-1,4-dien-3-one 294.4 g/mol MP: 110-11 (1E,4E)-1,5-di-o- tolylpenta-1,4- dien-3-one O (1E,4E)-1,5-di-o-tolylpenta-1,4-dien-3-one 262.3 g/mol MP; 98-100 (1E,4E)-1,5-di-p- tolylpenta-1,4- dien-3-one O (1E,4E)-1,5-di-p-tolylpenta-1,4-dien-3-one 262.3 g/mol MP:17 4-177

(1E,4E)-1,5-bis(4- methoxyphenyl)pe nta-1,4-dien-3-one O O O (1E,4E)-1,5-bis(4-methoxyphenyl)penta-1,4-dien 294.3 g/mol MP:12 8-132 V. Safety Information a. General Safety information i. Wear safety goggle, gloves and lab coat. ii. Ensure snorkel is working properly iii. Handle hot glassware carefully. b. Specific safety information Acetone- flammable, causes serious eye damage, can cause dizziness p-tolualdehyde- flammable, harmful if swallowed, can cause serious eye and skin irritation, may cause respiratory issues o-tolualdheyde- flammable, harmful if swallowed, can cause serious eye and skin irritation, may cause respiratory issues 4-Methoxybenzaldehyde- short and long term aquatic hazard Benzaldehyde- flammable, toxic if inhaled or ingested, can cause eye and skin irritation, toxic to respiratory system, harmful to aquatic life Ethanol- flammable, dp not inhale Sodium hydroxide- serious eye damage, corrosive to metals and skin (1E,4E)-1,5-diphenylpenta- 1,4-dien-3-one- harmful if swallowed, harmful to aquatic life (1E,4E)-1,4-di-o-tolylpenta-1,4-dien-3-one- harmful if swallowed, harmful to aquatic life (1E,4E)-1,5-di-p-tolylpenta-1,4-dien-3-one- harmful if swallowed, harmful to aquatic life (1E,4E)-1,5-bis(4-methoxyphenyl)penta- 1,4-dien-3-one- irritant VI. Experimental Procedure 1. Use 3 mL conical vial. Add 1.0 mL of ethanol, use 0.65 mL of aldehyde, and 0.20 mL of acetone. 2. Add three drops of sodium hydroxide to vial. 3. Cap and shake vial vigorously for several minutes. 4. Let reaction react at room temp for 15 min. 5. Shake vial at regular short intervals to ensure mixing. 6. Chill reaction mixture in ice bath after 15 min. 7. Use a mL of DI water to rinse reaction vessel. 8. Use suction filtration to separate crystals. 9. Use a mL of water and pour on top of crystals. 10. Repeat 3 more times. 11. Test pH of water coming out of funnel. Should be orangeish 12. Dry crystals with suction filtration for a couple of minutes. 13. Scrape crystals into 100 mL beaker.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version