“…Thus, 2% was achieved on 2%Ta 2 O 5 -98%SiO 2 [Jones et al, 1945]; 14% on hydroxyapatite [Tsuchida et al, 2008]; 16% on MgO/SiO 2 [Kvisle et al, 1988]; 25% on 1%Ag-10%ZrO 2 -500%SiO 2 [Jones et al, 1945]; and 52, 56 and 58% on ZnO-MgO/SiO 2 , Ag-MgO/SiO 2 , and CuO-MgO/SiO 2 , respectively [Makshina et al, 2012]. The values above correspond to 1,3-butadiene yield from pure ethanol, without addition of reaction promoters (e.g., acetaldehyde, crotonaldehyde, hydrogen) in the feed stream to the reactor, commonly used to improve the 1,3-butadiene yield [Ordomskiy et al, 2012;Jones et al, 2011;Bhattacharyya and Sanyal, 1967;Bhattacharyya and Avasthi, 1966;Corson et al, 1950].…”