Low-temperature oxidation of a gasoline surrogate: Experimental investigation in JSR and RCM using high-resolution mass spectrometry

The oxidation of a gasoline model-fuel (2500 ppm n-heptane and 2500 isooctane), called RON 50, was studied in jet-stirred reactor (JSR) over the temperature range 560 ? 700 K, at total pressure 10 atm, residence time 1.5 s, an equivalence ratio 0.5. Gas samples were collected as function temperature. Ignition 50/air mixtures also rapid compression machine (RCM) under same fuel-lean conditions, 20 bar, 640 K. variable reaction time. Products low-T formed dissolved acetonitrile analyzed by high-resolution mass spectrometry. Flow injection analyses ultrahigh-pressure liquid chromatography coupled to Orbitrap? used characterize wide species such hydroperoxides, diols, ketohydroperoxides, carboxylic acids, diketones, cyclic ethers (CnH2nO) decomposition alkyl hydroperoxy radicals, highly oxidized via up six O2 additions on radicals (CnH2nO11). Mass spectrometry conducted using atmospheric chemical ionization running negative positive modes. For confirming presence –OH or –OOH groups products, we performed H/D exchange addition D2O samples. Under JSR observed products: C7H14Ox (x = 1?11), C7H12Ox C7H10Ox 1?9), C7H8Ox C7H6Ox 1?8), C7H4Ox 1?6). Similarly, following products isooctane observed: C8H16Ox 1?12), C8H14Ox C8H12Ox C8H10Ox 2?10), C8H8Ox 2?8), C8H6Ox 1?7). Finally, CnH2n (n 4?8), CnH2n-2 CnH2nO 3?8), CnH2n-2O CnH2n-4O CnH2n+2O2 CnH2nO2 CnH2n-2O2 CnH2n-4O2 CnH2nO3 2?8) observed. Most these detected RCM measurements indicated that 50 routes are similar experimental conditions. A kinetic mechanism compare formation versus JSR. New pathways need be introduced existing schemes for predicting newly cool-flame products.