Question

You will apply what you have learned earlier in the semester when performing the Acid-Base Extraction experiment to perform a different separation: that of an organic neutral compound and organic base. You will also need to purify and characterize these compounds.

You will have one lab period to execute your plan for separating the assigned mixture given below. There will be a 1:1 (by mass) mixture placed in the lab: 1,4-dichlorobenzene/ethyl 4-aminobenzoate. You will take approximately 1 g of your mixture and dissolve it in diethyl ether. Be aware that ether easily evaporates so you may need to add more. You will then use extraction to separate the two compounds. You will need to characterize your crude separated compounds by TLC, recrystallize and characterize your pure compounds by TLC and melting point, in addition to determining the percent recovery.

You must include procedures for:

a. Extraction

b. Recrystallization of separated compounds

c. Two methods for characterization of pure separated compounds (do not include 1H NMR since there is not enough time to obtain NMR spectra for everyone.)

Provided Substances:

●1:1 mixture (by mass) of 1,4-dichlorobenzene/ethyl 4-aminobenzoate

●Pure 1,4-dichlorobenzene for comparison

●Pure ethyl 4-aminobenzoatefor comparison

●Sodium sulfate

●Diethyl ether

●Hydrochloric acid (1 M or 3 M)

●Sodium hydroxide (3 M or 6 M)

●TLC solvents (pre-mixed ethyl acetate/hexanes mixture)

●Dichloromethane for dissolving samples for TLC

●95% ethanol

●Distilled water

Solubility Information

(Useful when choosing a solvent for recrystallization. Hint: Make sure you understand how to use a mixed solvent when doing a recrystallization.)

●ethyl 4-aminobenzoate is soluble in hot and cold ethanol and virtually insoluble in cold water●1,4-dichlorobenzene is soluble in hot and cold ethanol and virtually insoluble in cold water

Where im at ( please fill in details)

I know the ethyl 4 – amino benzoate is the base and will react with Hcl to for the aqueous layer, and the 1,4- dichlorobenzene will dissolve in the diethyl ether. Once separated ( correct if wrong) ill reconstitute the aqueous phase with sodium hydroxide. I am unsure what to do in order to reconstitute the organic phase. At this point I am not sure what the listed Sodium sulfate will be used for. Also, please provide specific course of action to consider for going about the recrystallization process as far as ensuring purity, riding all side products ect. Thank you very much!

Answer 1

Mixture of toer Add 1(M) Ace to the Mixture & extract it with Diethyl ether I Aquous layer tonganic Layer (+)NH2 -OEL Remove Etro by nota vaccum then make saturate solution of it in hot Etoh & let it crystalize without disturbing. If it doesnot add little amount of water to salt out. Layer Add 1(M) NaOH to convert the salt to Ethyl 4-amino bentrate. Then extract it with Diethyl etuer I Aq layer organic Nat & la o ott Dry the organic I layer over Sodium Sulfate to remove water further O Almost free of H2O remove Etao & then make saturated solution of it in hot Ethanol. Let it recrystalize. If it doesnot add little amount of H₂O so that it start crystalizing as ito insoluble & water via salting out mechanism

• Dissolve the crystals of each compound Separated in DCM & run it in Ethyl acetate & hexane mixture in TLC with known. sample. If the spot matches giving the same Rf value then it is confirmed o characterisation can be done using IR . For ethyl 4-Aminobenzoate characteristics peak at N1735 con for ester i stretch a two sharp peak ~ 3300-340o com will appear for N-4 stretch . For 2 dichlore benzene peak es for c (SP2) - It stretch at ~3100 cant • Melting point can be checked & matched with literature • HRMS & GCMS can be done aswell