(Tribology) One of the major reasons for engine oil degradation is the oxidation of the mo...

(Tribology) One of the major reasons for engine oil degradation is the oxidation of the motor oil. To retard the degradation process, most oils contain an antioxidant [see Incl. Eng. Chew. 26, 902 (1987)]. Without an inhibitor to oxidation present, the suggested mechanism at low temperatures is

where I2 is an initiator and RH is the hydrocarbon in the oil.

Go Blue Motor Oil

When an antioxidant is added to retard degradation at low temperatures, the following additional termination steps occur:

(a) Derive a rate law for the degradation of the motor oil in the absence of an antioxidant at low temperatures.

(b) Derive a rate law for the rate of degradation of the motor oil in the presence of an antioxidant for low temperatures.

(c) How would your answer to part (a) change if the radicals /• were produced at a constant rate in the engine and then found their way into the oil?

(d) Sketch a reaction pathway diagram for both high and low temperatures, with and without antioxidant.

(e) See the open-ended problems on the CD-ROM for more on this problem.

(f) List ways you can work this problem incorrectly.

(g) How could you make this problem more difficult?