196REDUCTION WITH ALUMINUM ALKOXIDES .(LXVII) andbenzyl isovanillin (LXVIII) have been obtainedwithlessthan oneequivalent of aluminum isopropoxide.47-48With benzalde-hydeWi'7anexoessofreagentgives only 55-65% yields of benzyl alcohol10 CHOLXVIwith considerable benzyl benzoate resulting from the Tishchenko reac-tion. However, with only one-half an equivalent of reagent37an 89%yield of benzyl alcohol is obtained (ProcedureII, p.201),ApparatusThe simplest type of apparatus, and one which is quite satisfactoryexcept in the reduction of volatile ketones and aldehydes, consists of around-bottomed flask equipped with a short reflux condenser (no waterin the cooling jacket), attached at the top to another condenser set fordistillation (see Procedure IV, p. 203). When the distillate no longergives a test for acetone, the reduction is complete. If more than half ofthe solvent distils during the reaction it is advisable to add more iso-propyl alcohol to maintain the volume. If a concentrated solution is tobe avoided, a two-necked flask may be employed and fresh isopropyl
This is the end of the preview.
access the rest of the document.