Pressure effect on the rate and equilibrium constants of the Diels-Alder reaction 9-chloroanthracene with tetracyanoethylene

The pressure effect on the forward and backward rate constants and equilibr ium constants of the Diels-Alder reaction of 9-chloroanthracene with tetrac yanoethylene has been investigated in 1,2-dichloroethane up to 1000 kg cm(- 2) at 298.15 K. The reaction volume obtained from the pressure effect on eq uilibrium (-20.6 +/- 1.5 cm(3) mol(-1)) and as difference of activation vol umes of forward (-28.5 +/- 1.5) and backward (-6.5 +/- 0.5) reaction (-22.0 +/- 1.5 cm(3) mol(-1)) are in agreement with partial molar volume differen ce of adduct (255.5 +/- 1.5) {diene (170.7 +/- 0.5) and dienophile (107.8 /- 0.2)} giving -23.0 +/- 2 cm(3) mol(-1). (C) 1999 Elsevier Science Ltd. A ll rights reserved.