신국승  차미선  강경구  이창수

Vol. 29,  No. 2, pp. 79-86, Jun.  2023
10.7464/ksct.2023.29.2.79

Hetero Diels-Alder reaction α β-unsaturated aldehyde Diol Selective hydrogenation

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The homogeneous catalyst, Ru-MACHO-BH, selectively performs hydrogenation reactions only on the carbonyl group of α, β-unsaturated aldehyde compounds with extremely high reactivity and selectivity. However, the hydrogenation of α, β-unsaturated aldehydes involves a heterogeneous Diels-Alder reaction, resulting in the formation of significant amounts of byproducts, such as dimers. In this study, we used the Ru-MACHO-BH catalyst (Carbonyl hydrido (tetrahydroborato) [bis (2-diphenyl phosphino ethyl) amino] ruthenium(II)) to selectively hydrogenate the carbonyl group of a specific type of α, β-unsaturated aldehyde called methacryl aldehyde, leading to the synthesis of methallyl alcohol. Simultaneously, we applied diols to inhibit the formation of byproducts. The results demonstrate that monoethylene glycol can significantly reduce the formation of diols. Based on these results, we effectively suppressed the formation of dimers containing vinyl groups in methacryl aldehyde by using hydroquinone, which can efficiently inhibit the chemical interaction of vinyl groups. Consequently, the conversion rate of methacryl aldehyde was increased. Ultimately, by reducing the amount of the expensive homogeneous catalyst Ru-MACHO-BH to 1/10, we achieved a selectivity of over 90% and a yield of over 80% for the desired product, methallyl alcohol. These results provide a method to minimize yield reduction while reducing the usage of expensive catalysts, thereby improving cost-effectiveness. We expect that the reaction could be applied to various kinds of selective hydrogenation and has been successfully run on an industrial scale.