Question

These questions are about a lab on Grignard Reactions

10. (3) If you had done this reaction in the lab, you would have added the Grignard reagent to a carbonyl containing molecules such as the ones from question 3. After addition the reaction is usually opaque and forms white precipitate, what is the precipitate made of? In other words, what are the salts that form?

11. (3) After these salts have formed, the reaction is quenched with acid, 5 N HCl. The acidic workup neutralizes the salt and your compound is easily extracted into an organic layer, what is happening in this work up that allows your compound to now be extracted?

12. (3) A student runs a Grignard reaction and does not quench with acid, he proceeds to extract with ether, then he dries and concentrates the organic layers to find that he has no compound. Where is his compound?

13. (3) The final step of a synthesis is to purify your compound, usually this is done by distillation. With the knowledge you have on column chromatography, which compound will come out of the column, A primary alcohol or a secondary alcohol?

Any help would be appreciated, I am just really lost as there is no textbook to go with it, just a video for online learning now in place of an in person lab.

Answer 1

Answer. 10 (3) After grignard reaction forms white precipitate After adan of grignano reagent (Rmgx) to carbonyl campound (RULR) to torms salt (white ppred) in organic Solvent omg Br Romg x + RILR THE RY (ang Br) R salt (white ppted) 123) After reaction Completion, then quenched with Snuel e acidic workup because salt breaks and forms alcohol product & mg Br. Compound get easily extracted in organic solvent and salt mg Br remains in aqueous ealer 12 (3) If Carignard reach not quench with curd then salt (R ²00 mg Br) does not break and it is remains as salt form, these salt is not extracted in organic solvent (ether). so other extraction salt is not exhalted Hence no compound or product in ether layer. 13 (3) In column chromatography : Seconday alcohol comes first then primary alcohol because in non polar phase See- alcohol comes first.