Diallyl Acetal

Commercial acetone dimethyl acetal and allyl alcohol from The Dow Chemical Company and cyclohexanone from Eastman Kodak Company were used without further treatment. 

These reaction products distil within a narrow range. The head temperature was maintained in the range 56-59°. About 750 ml. of distillate is collected, depending on the efficiency of fractionation. The combined amount of methanol and acetone 

The checkers used a 1.3x92 cm. vacuum-jacketed, silvered column packed with 0.25-in. glass ring chains. With this column it was necessary to carry out the distillation of benzene-acetone-methanol using reflux ratios varying from 2 1 initially to 11 1 at the conclusion. The use of a shorter column is not satisfactory. 

Other soluble, non-volatile bases may be used to neutralize the acid. The reactants may be kept at room temperature safely after addition of base. 

An azeotrope of benzene and allyl alcohol distils at about 77°, followed by benzene. When the temperature in the boiling flask reaches 120-130°, the pressure is reduced and the remdning benzene is taken to a cold trap. 

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Rearrangement, acid-catalyzed, of cyclohexanone diallyl acetal to 2-allylcyclohexanone, 42,14 of e do-tetrahydrocyclopentadiene to adamantane, 42,9 pinacol, of 1,2-indanediol, 41, 53... 

Unsaturated acetals can be prepared by the acetalization of an unsaturated aldehyde. Acrolein diethyl acetal, CHj=CH — CH(OCHjCH,)j, is prepared in this manner and also by the dehydrohalogenation of /3-chlo-ropropionaldehyde diethyl acetal (cf. method 20) however, the former method has definite advantages in that it involves a single-step process and gives a more stable product. The double bond may also be in the alcohol fragment, as In acetaldehyde diallyl acetal,... 

A solution of 196 g. (1 mole) of cyclohexanone diallyl acetal (Note 1), 150 g. of toluene, and 0.10 g. of -toluenesulfonic acid is distilled through a good fractionating column (Note 2). In about 3 hours, 110 g. of distillate boiling at 91-92° (Note 3) is obtained and the temperature in the head then rises abruptly. 

The forerun contains some acetone diallyl acetal and about 35 0 g. of 2-allylcyclohexanone, b.p. 78°/10 mm. 

Cyclohexanone diallyl acetal has been prepared from cyclohexanone and allyl orthosilicate and by the above procedure. ... 

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