Hexaldehyde ethyl orthoformate method

The ethyl orthoformate required in this preparation may be prepared by the action of sodium upon a mixture of chloroform and dry alcohol  

Carry out a second run with the recovered chloroform-alcohol mixture (A) add 100 g. of dry chloroform and sufficient super-dry ethyl alcohol (200-250 ml.) to give a total volume of 750 ml. Add 52 g. of sodium as before. Remove the excess of chloroform and afoohol as before on a water bath through a fractionating column, add the intermediate fraction (B) from the first run, and fractionate again. The yield of product b.p. 144 146°, is 45 g. 

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The reaction of ethyl orthoformate and Grignard reagents gives acetals which are hydrolyzed readily by dilute acid to aldehydes. This method has been employed extensively for the preparation of aliphatic and aromatic aldehydes. A study of the optimum conditions has been made, using the conversion of bromobenzene to benzaldehyde as a model synthesis (90%), Comparative studies of various aldehyde syntheses that employ Grignard reagents (methods 154, 166, and 167) show that this one is the most practical however, the possibility of a sudden exothermic reaction limits the size of the run. Longer reaction times at room or reflux tempjerature help overcome this difficulty. Examples of the better preparative procedures are found in those for -hexaldehyde (50%), p-tolualdehyde (TS ), " and phenanthrene-S>-aldehyde (42%)." ... 

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