Process for the production of ketones and aldehydes

摘要

As catalysts in the vapour-phase condensation of ketones and aldehydes with themselves or with one another in the presence of hydrogen, use is made of mixtures containing an oxide of an element of Group II and an oxide of an element of Group V of the periodic system. Specified catalysts comprise (a) zinc oxide and bismuth trioxide, (b) magnesium oxide and vanadium pentoxide, (c) barium oxide and bismuth trioxide and (d) magnesium oxide and bismuth trioxide deposited in each case on steel turnings. Other specified carriers for the catalysts are diatomaceous earth, bentonite and talc.ALSO:The condensation of a ketone with itself or with another ketone or with an aldehyde is effected by bringing the vaporized starting material together with hydrogen into contact with a catalyst comprising an oxide of an element of Group II and an oxide of an element of Group V of the periodic system. The products are generally unsaturated ketones, but saturated ketones may also be formed when the starting material contains five or more carbon atoms. The condensation of an aldehyde with itself or with another aldehyde is effected in the same way, the products in this case being unsaturated aldehydes. The reaction may be effected at 200-600 DEG C., preferably at 350-450 DEG C., and at atmospheric or raised pressure. In the examples: (1) vaporized methyl ethyl ketone and hydrogen are passed over a heated catalyst prepared by depositing a mixture of zinc oxide and bismuth trioxide on steel turnings; the products include methylheptenones and some secondary butyl alcohol; (2) vaporized acetone and hydrogen are passed over a heated catalyst comprising magnesium oxide and vanadium pentoxide or (example 3) barium oxide and bismuth trioxide or (example 4) magnesium oxide and bismuth trioxide on steel turnings; mesityl oxide is recovered in each case from the product; (5)-(7) acetaldehyde vapour and hydrogen are passed over the catalysts of examples (1), (2) and (4), to yield products containing crotonaldehyde; (8) a vaporized mixture of acetaldehyde and acetone is passed with hydrogen over the catalyst of example (1) to yield a product containing pentene-2-one-4; (9) a vaporized mixture of acetaldehyde and methyl ethyl ketone is passed with hydrogen over the catalyst of example (4) or (example 10) the catalyst of example (2) to yield products containing hexene-2-one-4. Reference is made also to the treatment of methyl-n-propyl ketone, methyl isopropyl ketone, methyl - n - butyl ketone, methyl isobutyl ketone, propionaldehyde, butyraldehyde, alicyclic ketones such as cyclopentanone and cyclohexanone, and ketones and aldehydes containing aryl, alkaryl or aralkyl groups. The reduction of the products to saturated ketones or aldehydes or to secondary or primary alcohols is mentioned. Other carriers on which the catalysts may be deposited are diatomaceous earth, bentonite and talc.