Carbonyl condensation reactions play an extremely important role in organic synt
ID: 970856 • Letter: C
Question
Carbonyl condensation reactions play an extremely important role in organic synthetic transformations. However, due to the long reaction times generally required for the reactions to reach equilibrium, they are seldom studied as part of the standard organic laboratory. Recent improvements in solvent-free reaction methods have greatly reduced reaction times necessary for reasonable conversions in Claisen condensations. Recently, there has been a major push in the chemical field towards "green chemistry", which involves an effort to reduce or eliminate the use or generation of hazardous substances during the manufacture and use of chemical products and processes. The Material Safety Data Sheets (MSDS) for all the chemicals involved in this lab are on iLearn. Read these and answer the following questions: Which chemical is the most dangerous in this lab? Explain why you chose your answer for part a), and the safety precautions you will take when handling this material. Fill in the reaction table below. Make sure you correctly calculate the molar amounts of your reactive materials. Calculate the Theoretical Yield of your product, i.e. the mass you would expect to recover (assuming 100% conversion to product). Explain the benefits of performing a "solvent free" reaction, as opposed to one that requires an organic solvent. Explain why we perform a "self-condensation" here. What would happen if we used one molar equivalent of ethylphenylacetate and one molar equivalent of methytphenylacetate?Explanation / Answer
Q.1: (a): 1M aqueous HCl is the most dangerous
(b): Because it causes burning of skin and severe skin daage and eye damage when come in contact. Handle the chemical with care and avoid skin ontact.
Use gloves, safety glasses, protective clothing. Wash hand properly after use.
Q.2: ethylphenyl acetate:
Chemical formulae = C10H12O2
Given the volume of ethylphenyl acetate = 0.500 mL
density of ethylphenyl acetate = 1.03 g/mL
Hence mass of ethylphenyl acetate = 0.500 mL x 1.03 g/mL = 0.515 g
Molecular weight, Mw = 164.20 g/mol
Hence moles-eqv of ethylphenyl acetate = mass / molar mass = 0.515 g / 164.20 g/mol = 0.00314 mol
mmol of ethylphenyl acetate = 0.00314 mol x (1000 mmol / 1 mol) = 3.14 mmol
Potassium tert-butoxide:
Chemical formulae = (CH3)3COK
Given the amount of Potassium tert-butoxide = 246 mg = 0.246 g
Molecular weight, Mw = 112.2 g/mol
Hence moles-eqv of Potassium tert-butoxide = mass / molar mass = 0.246 g / 112.2 g/mol = 0.00219 mol
mmol of Potassium tert-butoxide = 0.00219 mol x (1000 mmol / 1 mol) = 2.19 mmol
1 M aqueous HCl:
Chemical formulae - HCl
Product:
Chemical formulae - C18H18O3
Molecular weight, Mw = 282.33 g/mol
Theoritical mol - eqv of product = 0.00157 mol
mmol of product = 1.57 mmol
Q.3: From the given chemical reaction it is clear that 2 mol of ethylphenyl acetate produces 1 mol product.
Hence 3.14 mmol of ethylphenyl acetate will produce the amount of product
= 3.14 mmol / 2 = 1.57 mmol = 0.00157 mol product
Hence theoritical yield of the product = 0.00157 mol x 282.33 g/mol = 0.443 g (answer)