Question

see Vitc lab 2. The chromium oxidation of compound I below yields a mixture of products (II- V). Identify the order of elution that would occur if you used an alumina stationary phase with diethyl ether to separate the mixture of products (II, III, IV, V) by column chromatography. (Assume there is no starting material in the products.) (a) Write balanced redox reactions for the reaction of K Cr O, with I to give each of the products. Starting material PH CHCH-C(CH3)s I Products: CH3 CH3-C-OH CH3 CeH5C CHC OH CH5C-C(CH3)3 II III IV on conditions, chromium 6 can chromium 2 as the ion. reduce to chromium 4 as CrO2, chromium (a) Depending 3 as the ion, or

Answer 1

Alumina is a polar solid phase or adsorbent. The eluting solvent diethyl ether is non-polar.

So, the more polar products will adhere to the solid phase and the less polar components will elute easily.

The order of polarity is V > III> II > IV

So, the order of elution will be IV followed by II followed by III and lastly V.