1,3-Butadiene → 1,3-Butadiene

Participants

Reaction Conditions

Reaction Steps

Preparation of the polybutadiene dicarboxylic acid dimethyl ester used in Examples 1 to 6 and in Comparison Examples II and III is carried out by the bulk polymerisation of butadiene, for which purpose 325 g of 1,3-butadiene are added under nitrogen to quantities of 55 g, 39 g, 21 g and 7 g of azo-bis-isobutyric acid methyl ester. The reaction mixture is stirred for 14 to 16 hours at 80° C., the polymerisation reaction taking place under the natural pressure of the system (around 12 bars). Thereafter the excess butadiene is distilled off. Residual butadiene and tetramethyl succinic acid dimethyl ester, formed as a secondary product, are removed over a period of 6 hours at 0.1 mbar in a rotary evaporator (bath temperature 90° C.), leaving 174 g, 140 g, 95 g and 40 g, respectively, of a crystal-clear liquid having an Mn of 800 (as determined by vapour pressure osmosis) and containing 78 mole percent of 1,4-bonds; Mn 1000 and containing 79 mole percent of 1,4-bonds; Mn 1300 and containing 80 mole percent of 1,4-bonds; Mn 6000 and containing 82 mole percent of 1,4-bonds.

Provenance & Evidence