Theoretical Yield in Multi-Step Synthesis

[Soaring Crane]

Homework Statement

Exactly how do you find the theoretical yield of methyl m-nitrobenzoate from 10.0 g of benzoic acid?

Homework Equations

1) Ph-COOH + CH3OH + H2SO4 --> Ph-COOCH3
2) Ph-COOCH3 + HNO3 + H2SO4 --> methyl m-nitrobenzoate

The Attempt at a Solution

10.0 g benzoic acid*(1 mol benzoic acid/122.122 g benzoic acid)*(1 mol methyl benzoate/1 mol benzoic acid)*(136.149 g methyl benzoate/1 mol methyl benzoate) = 11.15 g methyl benzoate from FIRST STEP as theoretical yield

11.15 g methyl benzoate*(1 mol methyl benzoate/136.149 g methyl benzoate)*(1 mol methyl m-nitrobenzoate/1 mol methyl benzoate)*(181.147 g methyl m-nitrobenzoate/1 mol methyl m nitrobenzoate) = 14.83 g methyl m-nitrobenzoate from 10.0 g benzoic acid as theoretical yield?

Thanks.

 

[chemisttree]

That looks good if the formula wts. you give are accurate. I didn't check.
Also, you could have just multiplied the number of moles of benzoic acid by the formula wt. of m-nitromethylbenzoate.

 

[Blueshift5]

I would like to commend you for your attempt at solving this problem. Your approach is correct, and the equations you have used are appropriate for finding the theoretical yield of methyl m-nitrobenzoate from 10.0 g of benzoic acid. However, I would like to point out a few things that may help you improve your solution.

Firstly, when converting from grams to moles, it is important to use the molar mass of the specific compound, rather than the generic molar mass of the functional group. In this case, the molar mass of benzoic acid is 122.122 g/mol, while the molar mass of methyl benzoate is 136.149 g/mol. Therefore, the first step would be:

10.0 g benzoic acid*(1 mol benzoic acid/122.122 g benzoic acid) = 0.0819 mol benzoic acid

Similarly, for the second step, the correct conversion would be:

11.15 g methyl benzoate*(1 mol methyl benzoate/136.149 g methyl benzoate) = 0.0819 mol methyl benzoate

This is important because using the incorrect molar mass can lead to errors in the final result.

Secondly, when calculating the theoretical yield in a multi-step synthesis, it is important to consider the limiting reagent. In this case, the limiting reagent would be benzoic acid, as it is the starting material with the lowest number of moles. Therefore, the theoretical yield of methyl m-nitrobenzoate would be 11.15 g, as calculated in the first step.

Overall, your approach is correct, but it is important to use the correct molar masses and consider the limiting reagent when calculating the theoretical yield in a multi-step synthesis. Keep up the good work!