Synthesis of Co(Acac)3

Amanda Tran
Date of lab: 04/25/05
Date submitted: 05/09/05
Chem 2130-3

Experiment 3:
Synthesis of Co(acac-NO2)3

Introduction
In this lab, Co(acac·NO2)3 is synthesized using the Co(acac)3 complex produced in Experiment 2. The Co(acac)3 complex is used as a reagent instead of acacH because acacH cannot be directly converted to 3-nitroacetylacetone. Since Co(acac)3 is not stable in HNO3, Cu(NO3)2 and acetic anhydride are used in this reaction to produce the final product, Co(acac·NO2)3. The exact mechanism of the reaction is unknown, however, it is believed to proceed as follows:
1)
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2)
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Data and Calculations

Table 1: Measurements of weights and melting point
| |Weight (in grams) |MP (°C) |
|Cu(NO3)2·3H2O |1.3002 |-- |
|Co(acac)3 |0.4998 |-- |
|Sodium acetate trihydrate |1.5044 |-- |
|Co(acac-NO2)3 |0.3510 |182-187 |

Percent Yield Calculations: • Balanced Equations
Cu(NO3)2·3H2O + 2 C4H6O3 ( Cu(C2H3O2)2·3H2O + 2 C2H3O2NO2

2/3 Co(acac)3 + 2 C2H3O2NO2 ( 2/3 Co(acac-NO2)3 + 2 C2H3O2

• Moles of reagent used
- Cu(NO3)2·3H2O, MW: 241.59 g/mol
[pic]

- Acetic anhydride, MW: 102.1 g/mol, D: 1.080 g/mL
[pic]

- Co(acac)3, MW: 356.24 g/mol
[pic]

• Limiting Reagent
From the stoichiometry of the reactions, acetic anhydride is in excess, and 2/3 (0.67) mole Co(acac)3 should reaction with 1 mole copper nitrate trihydrate. The actual mole ratio when 0.49 g Co(acac)3