Cyclohexanone, dehydration agents

The adipic acid process we have developed involves butadiene oxidative carbonylation in the presence of methanol, a l, l-dimethoxycyclohexane dehydration agent, and a palladium(ll)/ copper(ll) redox catalyst system (Equation 1.). The reaction sequence includes an oxycarbonylation, hydrogenation and hydrolysis step(17-19). The net result is utilization of butadiene, the elements of synthesis gas, l, -dimethoxycyclohexane and air to give adipic acid, cyclohexanone and methanol. 

Recovered methanol and cyclohexanone are used to regenerate the l, l-dimethoxycyclohexane dehydration agent. 

Although many dehydration agents function effectively in butadiene oxycarbonylation, ketals proved to be easily regenerated and recycled. Cyclohexanone was chosen because of its more favorable equilibrium constant during regeneration(27,28)... 

The cycloalkylidene acetals are formed in essentially the same way as their iso-propylidene counterparts. Thus reaction of a diol with cyclopentanone [Scheme 3.42]M or cyclohexanone, usually with provision for the removal of water, accomplishes the transformation in good yield In the double protection of mannitol [Scheme 3.43], triethyl orthoformate served as the dehydrating agent and trifluoroborane etherate was the acid catalyst 65... 

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