Question

Assignment 5: Separation Scheme Correction On a page titled Incorrect Separation Scheme print the incorrect separation scheme provided for your molecule on Blackboard. The top of the separation scheme shows what other compound is mixed with your molecule. Assume for the purposes of this assignment that both compounds are solid at room temperature. Also assume that both compounds are soluble in ether, except ionic compounds. The goal of the separation is the isolate each of the two compounds from the mixture. oBelow the incorrect separation scheme write a discussion of this incorrect scheme identifying all of the mistakes in the separation scheme. Keep in mind that there will be more than one mistake in the scheme oFor each mistake, give a detailed, scientific explanation of why it is incorrect o All answers must be typed. No handwritten responses will be accepted. On a page titled Correct Separation Scheme draw using a chemical drawing program or other computer generated form, a correct separation scheme to isolate your molecule from the provided second molecule. Make sure to indicate the phase of each chemical in every step (s, I, g, aq) and write the separation technique used in each step (ie: vacuum filtration) The list below gives the reagents available in the lab. Use any of the reagents below to isolate the compounds. Remember that the simplest separation scheme is the best one. Try to avoid unnecessary steps. No hand drawn structures will be accepted. 10% aqueous NaOH 5% aqueous NaHCO 6М НCI 5% HCI Diethyl ether (ether) CH OH lithium aluminum hydride (LiAlH) Н.о Н.РО. anhydrous Na,SO4 anhydrous MgSO Saturated NaCI Sodium borohydride (NaBH) NaCl solid

Answer 1

Correct scheme: Но, aten beho 10% aq NaOH aq ether Natoa atu 10% HCI, vacuum filtration Na2SO4, gravity filtration HANether NaCl Na S04.10H20 evap, ether Do 2-3 times washing with Water and then with saturated NaCl solition. Descard the aqueus layer and then use further sepration.. HON ether

In the given incoorect scheme, mixture of phenol and amine was reacted with HCl. If this was done then rather that phenolic compound the amine would hav ereacted to give a salt. However, it is not the case. Hence the extraction reagent should be NaOH. HO 10% aq NaOH Nato H3C-o нсох After extraction of pehnolic compound the ether layer should be washed with water and then with the saturated solution of NaCl. these steps are missing. If we do not do that then there is a chance of getting traces of phenolic compund as a contamination to the amine.