Upper limits for the rate coefficients for reactions of BrO with formaldehyde and HBr

The reactions of the BrO radical with hydrogen bromide, BrO + HBr → HOBr + Br (R4) and with HCHO, BrO + HCHO → HOBr + HCO (R5) have been studied at 298 K, 1 atm. pressure in an environmental chamber. No conclusive evidence for the occurrence of either reaction was found and upper limits for both reaction rate coefficients are reported (k 4 , k 5 <4 × 10 −15 cm³ molecule −1 s −1 ). These upper limits are about 4–5 times lower than recent estimates [ Hansen et al., 1999a,b].