18-Crown-6 → p-Divinylbenzene

Participants

Reaction Conditions

Reaction Steps

Under N2, 248.3 g (1 mol) of 1,4-bis(2-acetaminoethyl)benzene, 11.2 g (100 mmol) of potassium tert.-butylate, 95% pure, 26.4 g (100 mmol) of 1,4,7,10,13,16-hexaoxacyclooctadecane (18-crown-6), 250 g of a mixture of isomeric phenoxydiphenyl ethers, 250 mg of tert.-butylcatechol and 250 mg of p-phenylenediamine are initially introduced into a distillation apparatus analogous to Example 1. An additional 250 mg of tert.-butylcatechol are placed in the distillation receiver. After a vacuum of 10 mbar has been applied, the temperature of the bottom is increased. The cleavage reaction starts at about 175° C. and is detectable by the appearance of the products in the still head. The reaction is completed in 1-2 h by slowly increasing the bottom temperature to 210° C. Finally, the vacuum is increased to 5 mbar for a short time. The distillate is taken up in 300 ml of ether and 200 ml of water, the aqueous phase is separated off, and the organic phase is washed once more with 200 ml of water, dried with sodium sulfate and the solvent is removed by distillation in vacuo. 213.2 g of residue contains 58.4% of p-divinylbenzene (96% of theory), 2.6% of 4-(2-acetaminoethyl)styrene and 37.3% of isomeric phenoxydiphenyl ethers. 111.0 g of p-divinylbenzene are obtained with a boiling point of 40°-41° C. at about 0.5 mbar after renewed distillation over a 20 cm Vigreux column. Yield 85% of theory. Purity 99.9%.

Provenance & Evidence