Photoacoustic Calorimetry is used to determine the a-C-H bond dissociation Energy (BDE) in 1,2,3,4-tetrahydronaphthalene (tetralin) in the neat liquid as well as in competition with hydrogen abstraction from tetrahydrofuran (THF). Also, the a-C-H BDE in THF was determined in the neat liquid. The experiments found to be 82.9 +/- 1.2 and BDE(gas)(THF) to be 92.1 +/- 1.6 kcal mol(-1). The revised global rate constant of hydrogen abstraction from THF is found to be 4.6 x 10(6) M(-1) s(-1) at 297 K.