problem 1: In the year 1968, the Shell Oil Company reported that adding tertiary phosphine such as PBu₃ to the oxo reaction resulted in hydroformylation occurring at less than 100 atm. Although the new catalyst is a less active hydroformylation catalyst than HCo(CO)₃, it is a better hydrogenation catalyst. Separation of catalyst from products is enhanced. The ratio of linear to branched product is as high as 9 to 1. Studies of the reaction failed to observe alkyl or acyl-containing intermediates.

a) Describe the greater selectivity of the new catalyst by drawing a suitable transition state.
b) What are the merits and demerits of the new catalyst being a good hydrogenation catalyst?
c) What does the failure to observe intermediates tell you regarding the likely rate-determining step?
d) Why it is simpler to eradicate the products from the catalyst?

problem 2: Draw a catalytic cycle for phosphine-rhodium-catalyzed hydroformylation. The catalyst precursor is:

H(CO)Rh(PPh₃)₃

problem 3: Describe why increasing the concentration of phosphine in the phosphine-rhodium cycle exhibits the reaction rate, however as well raises the linear or branched product ratio.

problem 4: Rate of Rh/HI-catalyzed carbonylation of 2-propanol to give a mixture of butanoic and 2-methylpropanoic acids is actually a little faster than that for carbonylation of ethanol and up to seven times more fast than that for 1-propanol. If OA is still the rds in the pathway, what can be said regarding the method of that step when 2-propanol is the starting material?