182 REDUCTION WITH ALUMINUM ALKOXIDES been achieved with aluminum ethoxide, especially in the reduction of aromatic aldehydes. 2-12 < 14 > 16-16 In general, the yields in aluminum isopropoxide reductions range from 80 to 100%. With a few low-boiling ketones difficulty may be experi-enced in separating the resulting alcohol from isopropyl alcohol; thus the yields of reduction products from diethyl ketone ^ and methoxyacetone n are reported to be 60% and 40%, respectively. Di-n-propyl ketone, on the other hand, gives a 92% yield of the carbinol. 8 As would be expected, side reactions are more significant and the yields are consequently lower when extremely sensitive compounds, such as unsaturated aldehydes and the carotenoids, are reduced. The time required for a reduction varies greatly with the particular aldehyde or ketone; the aldehydes are usually more reactive. Quinone and cyclohexanone are reduced completely in a few minutes; camphor requires twelve to twenty-four hours. The rate of reduction also de-
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