Lab 10 Aldol Condensatio. are a claRe of compounde that contain an aromatic keto

Question

Lab 10 Aldol Condensatio. are a claRe of compounde that contain an aromatic ketone and an enone that forms the central core for a variety of important biological pounds. Benzylideneacetophenone is the parent member of the chalcones. Chalconee and their derivative demonstrate wide range of biological activities which are gaining importance in the world medicine and cancer treatment due to their antinammanory, antinumor, antihacerial antifangal, benailidene chaleone and antioxidant Properties. 4-methoxychalcone is readily prepared by condensation of acetophenone with panisaldehyde. The aldehyde carbonyl is more reactive than that of the ketone and therefore reacts rapidly with the anion of the ketone to give a P- which earily undergoes base-catalyzed hydrokyketone, dehydration. EtOH p-anisaldehyde Chemical Formula CHvo Chemical Formula CieHidor Molecular Weight: 120.15 Chemical Formula ClLOh Molecular Weight 238.28 Molecular weight: 136.15 eagents and Equipment Need 25 mL Erlenmenyer flask Magnetic Stir Bar Hot Plate Filter Flask AniRaldehyde Acetophenone Ethanol Sodium Hydroxide Experimental Procedure To a 125 mL Erlenmeyer flank add 30 mLof9s ethanol, 20 ml of 20%NaOH and 400 mL of p-aniraldehyde with etirring. Allow reaction mixture to stir for 5 minutes and then add exactly 300 mL of acetophenone. (DROPWisE 2. Mix reaction for 1 hour during which time the olution will change color, followed by the of a beige precipitate. 3 After 1 hr, recover your product through Wash the crystals with two 35 mL portions of distilled water to remove alltraces of the base Dixpone of vacuum filtration waste in appropriate bottle in hood. Recrystallize the crude product from ethanol tarting with 30-40 ml of EtOH Separate the recrystallized product from the ethanol by filtration, washing the product with two 15 mLportiona ofice cold ethanol. Refilter the filtrate if necessary Place the crystals from the vacuum filtration on a eighed watch glass and store until the next lab period. a. Determine the mass of the dried product. b. Determine melting point of the product lit map. 73-75 Questions 1. Write a detailed mechanism for the Aldolcondeneation between 1 mol of p-anialdehyde and acetophenone.

Explanation / Answer

Density = m/v

m = desnity x volume

mass of anisaldehyde = 1.12 x 4 = 4.48 g

moles of anisaldehyde = weight in gram/molecular weight = 4.48/136.15 = 0.0329

mass of acetophenone = 1.03 x 3 = 3.09 g

moles of acetophenone = 3.09/120.15 = 0.0257

The acetophenone is the limiting reagent for the reaction .

0.0257 g of acetophenone will give 0.0257 g of benzilidene chalcone

i.e. 0.0257 x 238.28 = 6.12 g

theoretical yield of benzilidene chalcone is 6.12 g

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