CH3CH2OHA() + HOHB() CH3CH2OHB() + HOHA()

CH3CH2OHA() + HOHB() CH3CH2OHB() + HOHA()

CH3CH2OHA() + HOHB() CH3CH2OHB() + HOHA()

CH3CH2OHA() + HOHB() CH3CH2OHB() + HOHA()