Question

K2CO3 1.5 H20 Br он heat 2,3-dibromocinnamic acid trans-1-bromo-2-phenylethene Compound MW mp (C)bp (C) density (g/ml) mol) 2,3-dibromocinnamic acid 307.97 93-95 (threo) n'a n a 202-204 (erythro)E K CO.1.5H:O1 methylene chloride 138.21 84.93 56.11 891 na n a n'a 39.6 n a n a 1.33 n a 3 MKOH 2. a. What is the by-product formed in this reaction (not shown in given reaction equation)? b. What is the purpose of adding 3 M KOH at the beginning of the extraction process? c. Which layer does the 3 M KOH solution mix with? Aqueous or organic? 3. A student repeated the same experiment but used ethyl acetate (CHCOCKİCH) as the extracting solvent to isolate the product. The density of ethyl acetate is 0.902 g/mL a. What will the student observe when ethyl acetate is added to the reaction mixture in the separatory funnel? Will the liquids mix or will the liquids be immiscible leading to formation of two layers? b. If your answer in part a was that the liquids will mix, then explain why. If your answer was that the liquids will be immiscible, then explain which layer will be the top and which will be the bottom. Indicate what you based your decision on. 4 A student perfomed the extraction procedture but decided to do one extraction of the aqueous layer with 15 mL of methylene chloride (added all at once) Will this be more or less efficient in extracting more organic compound out of the aqueous layer? Briefly explain

Answer 1

0% K,C03, 1.5H20 он Heat trans-1-bromo-2-phenylethene 2 3-dibromocinnamic acic cis-1-bromo-2-phenylethene (a) By Product formed in the reaction is cis-1-bromo-2-phenylethene. (b) 2 3-dibromocinnamic acid is reacting with KOH and form an acid salt which is soluble in water. So, un-reacted starting material can be separate out from the reaction mixture. (c) 3 M KOH mix well with Aqueous phase. (a)Ethyl acetate is immiscible with water. So, it will be separate in the funnel (b) Ethyl acetate will be in top layer because its density is lower 0.90 g/cm3 compared to water 1 g/cm3. Methylene chloride will be the more efficient as it has less polarity compared to ethyl acetate.