935-79-5

Preparation

A flask containing 500 ml of dry benzene and 196 gm (2 moles) of maleic anhydride is heated with a pan of hot water while butadiene is introduced rapidly (0.6-0.8 liter/min) from a commercial cylinder. The solution is stirred rapidly and the heating is stopped after 3-5 min when the temperature reaches 50°C. In 15-25 min the reaction causes the temperature of the solution to reach 70-75°C. The absorption of the rapid stream of butadiene is nearly complete in 30-40 min. The addition of butadiene is continued at a slower rate for a total of 2\ hr. The solution is poured into a 1-liter beaker which is covered and kept at 0-5°C overnight. The product is collected on a large Buchner funnel and washed with 250 ml of b.p. 35-60°C petroleum ether. A second crop is obtained by diluting the filtrate with an additional 250 ml of petroleum ether. Both crops are dried to constant weight in an oven at 70-80°C to yield 281.5-294.5 gm (96- 97%, m.p. 99-102°C). Recrystallization from ligroin or ether raises the melting point to 103-104°C.

Synthesis Reference(s)

Journal of the American Chemical Society, 64, p. 802, 1942 DOI: 10.1021/ja01256a018