Question

(b) What is the purpose of boiling the initial reaction mixture? (c) Calculate % yield for your luminol product. Show the limiting reagent relationship between 3-nitrophthalic acid and hydrazine. Hydrazine 32(not 50.06)g/mol; assume all other reagents are in excess.

The initial reaction mixture of 1g 3-nitrophthalic acid, 2ml of 8% aqueous hydrazine and 3ml of triethylene glycol.

This was asked for the Synthesis of a Chemiluminescence Compound: Luminol (LAB)

Here is the data collected:

Answer 1

b) While boiling all the reactants can be mixed well to occur the reaction. Also boiling can provide threshold energy (minimum energy for the molecules to participate in reaction) to the reactants.

Moles of hydrazine = 2 mLxx 1.08 8g 1mol 1mL100g 32g = 0.005 mol 1mol Moles of 3-nitrophthalic acid = 0.9456 gx- 211.13 g = 0.0045 mol 3- nitrophthalic acid +hydrazine + 3-nitrophthalhydrazide 3-nitrophthalhydrazide- reckucing agent →Luminol From the stoichiometric equation one mole 3-nitrophthalic acid react with one mole hydrazine. There are less number of moles of 3-nitrophthalic acid. So it is limiting reagent. Theoretical yield of luminol 1mollumino1 yield = 0.0045 mol 3-nitrophthalic acidx= 3-nitrophthalic acid = 0.7972 g Luminol actual yield Percent yield = -X100 theoretical yield 177.16 g luminol 1 mol Luminol 0.71218 x100 0.7972 g = 89.3%