Process for producing ketoisophorone

#Attempts have already been made to oxidize .alpha.,.beta.-or .beta.,.gamma.-unsaturated aldehydes or ketones with the aid of a copper compound in the presence of a heterocyclic nitrogen base, which forms a complex compound with the catalyst, and an alkylamine.

#.beta.-Isophorone [3,5,5-trimethyl-cyclohex-3-en-1-one] has been oxidized to ketoisophorone [3,5,5-trimethyl-cyclohex-2-en-1,4-dione] for example with the aid of copper (ii) nitrate in the presence of pyridine and triethylamine in a nitrogen atmosphere. However, in this oxidation, by-products are formed to a considerable degree. These by-products including hydroxyisophorone [3,5,5-trimethyl-4-hydroxy-cyclohex-2-en-1-one], the difficulty separable .alpha.-isophorone [3,5,5-trimethyl-cyclohex-2-en-1-one] and dehydrodimers of isophorone. The yield of ketoisophorone which can be isolated by these procedures is very low, namely 30%. Therefore, a procedure is desired whereby the oxidation of .beta.-isophorone to ketoisophorone can be carried out systematically without the formation of undesired by-products and in high yields.

#In accordance with this invention, it has been found that .beta.-isophorone can be oxidized to ketoisophorone systematically in high yields, without the formation of undesirable and hard to separate by-products by oxidizing .beta.-isophorone which has the formula: ##STR1## with oxygen or an oxygen containing gas in the presence of a nitrogen containing organic base and as a catalyst, a salt of a metal selected from the group consisting of led, vanadium, chromium, manganese, iron or cobalt.

#The following Examples are illustrative but not limitative of the present invention:

#3,8 g. of lead acetate in 100 ml. of pyridine are treated with 69 g. of .beta.-isophorone. The mixture is gassed with oxygen at 70.degree. C. for 2 hours with intensive stirring and subsequently worked up by distillation. [b.p. 62.degree.-64.degree. C., 0,2 Torr]. The conversion of .beta.-isophorone used amounts to 31 g. corresponding 45%. Ketoisophorone is obtained in a yield of 26 g. corresponding to 76%.

#1,7 g. of vanadium isopropylate in 100 ml. of methanol and 50 ml. of pyridine are treated with 69 g. of .beta.-isophorone. The mixture is gassed with oxygen at 40.degree. C. for 2 hours with intensive stirring and subsequently worked up by distillation. The yield of crystalline ketoisophorone amounts to 53,2 g. corresponding to 70% [Conversion: 100%]