Weights of fumaric acid Melting Points of dimethyl fumarate 100°C dimethyl fumarate none Literature value: 102-106°C (lit) Source of literature value: https://www.scbt.com/p/dimethyl-fumarate-624-49-7#~ext-Melting%20Point%20%3A%20193°C%20(lit) QUESTIONS 1) What is your percent yield for dimethyl fumarate? Show your work. 2) What does your melting point data suggest about the purity of your dimethyl fumarate product?
The Correct Answer and Explanation is:
Here is the correct answer with explanation:
1) Percent Yield Calculation
To calculate the percent yield for dimethyl fumarate, the following formula applies:Percent Yield=(Actual YieldTheoretical Yield)×100\text{Percent Yield} = \left( \frac{\text{Actual Yield}}{\text{Theoretical Yield}} \right) \times 100Percent Yield=(Theoretical YieldActual Yield)×100
Unfortunately, the actual weight of fumaric acid used and the weight of dimethyl fumarate produced are not provided directly in the question. Assuming this information is available:
- Assume that XXX grams of fumaric acid were used.
- The molar mass of fumaric acid (C₄H₄O₄) = 116.07 g/mol.
- The molar mass of dimethyl fumarate (C₆H₈O₄) = 144.13 g/mol.
Assuming complete conversion, moles of fumaric acid used:Moles of fumaric acid=X g116.07 g/mol\text{Moles of fumaric acid} = \frac{X \, \text{g}}{116.07 \, \text{g/mol}}Moles of fumaric acid=116.07g/molXg
Since the reaction proceeds in a 1:1 molar ratio:Theoretical yield of dimethyl fumarate=(X116.07)×144.13 g\text{Theoretical yield of dimethyl fumarate} = \left( \frac{X}{116.07} \right) \times 144.13 \, \text{g}Theoretical yield of dimethyl fumarate=(116.07X)×144.13g
Once the actual yield (say, YYY grams) of dimethyl fumarate is measured:Percent yield=(Y(X116.07)×144.13)×100\text{Percent yield} = \left( \frac{Y}{\left( \frac{X}{116.07} \right) \times 144.13} \right) \times 100Percent yield=((116.07X)×144.13Y)×100
Insert actual values for XXX and YYY to compute the specific yield.
2) Analysis of Melting Point Data
The observed melting point of dimethyl fumarate is recorded as 100°C. The literature melting point for pure dimethyl fumarate is reported at 193°C. This significant difference indicates that the product likely contains impurities. Pure substances typically exhibit sharp melting points very close to their literature values. The substantial lowering of the melting point suggests contamination, possible incomplete reactions, or presence of side products. Such impurities disrupt the crystal lattice of the compound, leading to a depressed and broadened melting range.
In conclusion, the melting point data suggests that the synthesized dimethyl fumarate lacks high purity. Further purification steps such as recrystallization might be necessary to obtain a purer product.
If the exact weights of fumaric acid and dimethyl fumarate are provided, a full numerical yield calculation can be performed. Shall the data be available?
