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AssigneeTeijin Limited
InventorsYataro Ichikawa, Osamu Kobayashi, Kazuhiko Soma, Tatuyuki Naruchi, Yoshiyuki Yamanaka, Nobuo Suzuki
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A process for preparing .beta.,.gamma.-unsaturated aldehydes which comprises dehydrogenating .beta.,.gamma.-unsaturated alcohols in the vapor phase, preferably in the substantial absence of oxygen, using copper having a specific surface area of 0.01 to 1.5 m.sup.2 /g as a catalyst at a temperature of 150.degree. to 300.degree. C. The .beta.,.gamma.-unsaturated aldehydes can be recovered in pure form by distilling the dehydrogenation reaction mixture in the presence of water. The starting .beta.,.gamma.-unsaturated alcohols can be prepared by reacting olefins with formaldehyde or a derivative capable of forming formaldehyde at a temperature of 180.degree. to 400.degree. C. in the absence of a solvent or in the presence of a non-aqueous organic solvent after pre-heating said formaldehyde or derivative to a temperature of 85.degree. to 150.degree. C.
A process for preparing .alpha.,.gamma.-unsaturated aldehydes of the formula ##STR14## wherein R.sub.1, R.sub.2 and R.sub.3 are identical or different and represent a hydrogen atom or a methyl group, and R.sub.4 is a hydrogen atom or a linear or cyclic saturated or unsaturated hydrocarbon residue containing 1 to 6 carbon atoms, which comprises contacting a .beta.,.gamma.-unsaturated alcohol of the formula ##STR15## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are the same as defined above, in the vapor phase with metallic copper prepared by reduction of copper oxide having a specific surface area of 0.10 to 0.92 m.sup.2 /g as a catalyst at a temperature of 200.degree. to 280.degree. C in the presence of a carrier gas and in the substantial absence of oxygen.
A process for preparing .beta.,.gamma.-unsaturated aldehydes of the formula ##STR16## wherein R.sub.1, R.sub.2 and R.sub.3 are identical or different and represent a hydrogen atom or a methyl group, and R.sub.4 is a hydrogen atom or a linear or cyclic saturated or unsaturated hydrocarbon residue containing 1 to 6 carbon atoms, which comprises (1) reacting an olefin of the formula ##STR17## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are the same as defined above, with formaldehyde or a derivative capable of forming formaldehyde at the reaction temperature, at a reaction temperature of 200.degree. to 340.degree. C. in the absence of a solvent or in the presence of a non-aqueous organic solvent selected from the group consisting of halogenated hydrocarbons, diethyl ether, tetrahydrofuran, paradioxane, tetrahydropyran, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons and dioxanes after pre-heating said formaldehyde or derivative to a temperature of 85.degree. to 150.degree. C. thereby to form a .beta., .gamma.-unsaturated alcohol of the formula ##STR18## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are the same as defined above, and (2) contacting the .beta.,.gamma.-unsaturated alcohol in the vapor phase with metallic copper prepared by reduction of copper oxide having a specific surface area of 0.10 to 0.92 m.sup.2 /g as a catalyst at a temperature of 200.degree. to 280.degree. C. in the presence of a carrier gas and in the substantial absence of oxygen.
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