RATE CONSTANTS FOR THE GAS-PHASE REACTIONS OF SELECTED DIBASIC ESTERSWITH THE OH RADICAL

Using a relative rate method, rate constants have been measured for th e gasphase reactions of the OH radical with the dibasic esters dimethy l succinate [CH3OC(O)CH2CH2C(O)OCH3], dimethyl glutarate [CH3OC(O)CH2C H2CH2C(O)OCH3], and dimethyl adipate [CH3OC(O)CH2CH2CH2CH2C(O)OCH3] at 298 +/- 3 K. The rate constants obtained were tin units of 10(-12) cm (3) molecule(-1) s(-1)): dimethyl succinate, 1.4 +/- 0.6; dimethyl glu tarate, 3.3 +/- 1.1; and dimethyl adipate, 8.4 +/- 2.5, where the indi cated errors include the estimated overall uncertainty of +/-25% in th e rate constant for cyclohexane, the reference compound. The calculate d tropospheric lifetimes of these dibasic esters due to gas-phase reac tion with the OH radical range from 1.4 days for dimethyl adipate to 8 .3 days far dimethyl succinate for a 24 h average OH radical concentra tion of 1.0 x 10(6) molecule cm(-3). (C) 1998 John Wiley & Sons, Inc.