- Efficient conversion of ethanol to 1-butanol and C5-C9 alcohols over calcium carbide
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Production of 1-butanol or alcohols with 4-9 carbon atoms (C4-C9 alcohols) from widely available bio-ethanol has attracted much interest in recent years in academia and industry of renewable chemicals and liquid fuels. This work discloses for the first time that calcium carbide (CaC2) has a superior catalytic activity in condensation of ethanol to C4-C9 alcohols at 275-300 °C. The 1-butanol yield reached up to 24.5% with ethanol conversion of 62.4% at the optimized conditions. The by-products are mainly alcohols with 5-9 carbons besides 2-butanol, and the total yield of all the alcohols reached up to 56.3%. The reaction route was investigated through controlled experiments and quantitative analysis of the products. Results indicated that two reaction routes, aldol-condensation and self-condensation, took place simultaneously. The aldol-condensation route involves coupling of ethanol with acetaldehyde (formed from ethanol dehydrogenation) to form 2-butenol, which is subsequently hydrogenated to 1-butanol. The alkynyl moiety in CaC2 plays an important role in the catalytic pathways of both routes and affords the good activity of CaC2. CaC2 is converted to acetylene [C2H2] and calcium hydroxide [Ca(OH)2] simultaneously by the H2O that was generated from the condensation of alcohols.
- Wang, Dong,Liu, Zhenyu,Liu, Qingya
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p. 18941 - 18948
(2019/07/04)
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- Self-coupling of secondary alcohols by Ni/CeO2 catalyst
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Supported nickel catalysts are studied for the liquid phase CC self-coupling of aliphatic secondary alcohols under additive free conditions in N2 atmosphere. Among various Ni catalysts, 1 or 3 wt% Ni/CeO 2 catalysts pre-reduced in H2 shows highest yield (94%) of a dimer product (a higher ketone) for the self-coupling of 1-octanol at 130 C, and the catalyst is reused. The catalysts are also effective for self-coupling of various secondary alcohols, providing the first heterogeneous catalytic system for the self-coupling of secondary alcohols under mild conditions. Effects of support material and oxidation state of Ni on the activity are studied and it is found that both CeO2 and metallic Ni are indispensable for the reaction. A possible reaction mechanism is proposed, in which ketones, formed by dehydrogenation of alcohol, undergone Aldol condensation to give α,β-unsaturated ketone which is finally hydrogenated by in situ formed NiH species.
- Shimura, Katsuya,Kon, Kenichi,Hakim Siddiki,Shimizu, Ken-Ichi
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p. 137 - 142
(2013/07/26)
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- Efficient catalytic reduction of ketones with formic acid and ruthenium complexes
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The ruthenium complex (η5-C4Ph4COHOC4Ph4-η5)( μ-H)(CO)4Ru2 and its phenyl ring-substituted derivatives were found to act as efficient catalysts in reduction reactions of aldehydes and ketones to alcohols, using formic acid as H source. Excess formic acid accelerates the reaction, and the corresponding formate esters were isolated as sole products. Turnover numbers of up to 8000 (alcohols) and 11000 (formate esters) were attained, with yields in the order of 90%. Alkenes are not reactive, however, double bonds conjugated to a carbonyl group are selectively reduced under the reaction conditions. The reaction is compatible with a variety of ketones, but with aliphatic aldehydes the reaction is not selective, inasmuch as aldol condensation products are formed.
- Menashe, Naim,Salant, Einat,Shvo, Youval
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