For R2, amongst the impurities, we noted a recurrence of 1-ethyl-4-isobutylbenzene, which was also noted as an impurity in R1. Such impurities, occurring in multiple steps suggest the need for the development of purification catered to similar or same impurities in each step and underscore the need for unit operation in each step where the impurities occur. R3 produced a major impurity -3-(4-isobutylphenyl)butan-2-one, and its dimerized impurities.