Thermolytic reactions of dodecane

Abstract

Dodecane thermolysis was investigated under moderate temperatures and high pressures of N2 or H2. Dodecane is stable below 600 K, whereas under severe conditions it is thermolyzed to give a series of paraffins and olefins up to C22 but with C13 missing. High reaction pressure favors the formation of saturated hydrocarbons and shifts the product distribution toward heavier components. The yield of paraffin plus olefin of the same carbon number decreases with increasing molecular weight, and the yield of the olefin is slightly higher than that of its paraffin counterpart. These observations can be satisfactorily interpreted by a free-radical-chain mechanism with certain modifications. Hydrogen participates in dodecane thermolysis through radical-capping reactions. The pseudofirst-order rate law applies to dodecane disappearance. Recently, Rebick (1981) and Mushrush and Hazlett (1984) also reported some data on hexadecane pyrolysis. Freeradical mechanisms have been shown by the authors, and first-order kinetics was obtained or adopted. Comparison between observed and predicted products by the radical-chain theory gave good agreement (Voge and Good, 1949;Rebick, 1983).The reaction conditions in our study were directed toward relatively low severity because of our interest to use dodecane as a solvent. The confounding effects of the reaction products of the solvent on other reactants were sought.

Evaluation and Testing of the Suitability of a Coal-Based Jet Fuel

“…For the test with the outlet temperature of 985F, conversions from 25-35% were observed for the long-chain alkanes (tridecane to octadecane) with formation of lower molecular weight alkanes, alkenes and aromatics. These products, along with the formation of gaseous species (not identified but most likely C 1 -C 6 alkanes and alkenes), are consistent with the free radical reaction chemistry observed during pyrolytic decomposition of long-chain hydrocarbons at intermediate temperature/high pressure for short reaction times (Fabuss et al, 1964;Mushrush and Hazlett, 1984;Zhou and Crynes, 1985;Ford, 1986;Song et al, 1994a). Pyrolytic testing with the coal-based fuel was initiated with a furnace temperature of 1418F (770C) for comparison to the JP-8 testing.…”

High pressure pyrolysis of n-heptane

“…These authors also modified the free radical mechanism of Rice and Kossiakoff to account for the products formed under high pressure gas-phase pyrolysis [25]. Pyrolysis of several hydrocarbons such as n-hexadecane [26][27][28][29][30][31][32], decalin [28], C 21 -C 27 paraffins [30], dodecane [33], C 9 -C 22 alkanes [34], and pristane, phytane and squalane [35] have been investigated at high pressures. Song et al [36] investigated the condensed-phase pyrolysis of n-tetradecane at elevated pressures.…”

Decomposition Measurements of RP-1, RP-2, JP-7, n-Dodecane, and Tetrahydroquinoline in Shock Tubes

“…In a following publication, Voge and Good reported similar measurements for n-hexadecane, listed the currently existing thermal cracking rates for n-alkanes H from C 4 to C 16 , and proposed an empirical correlation between decomposition rate and carbon number [8]. In 1986, Zhou and Crynes reported pseudo-first-order rate constants at 623 and 673 K for the decomposition of n-dodecane in a batch reactor pressurized to 9.2 MPa (91 atm) with nitrogen or hydrogen [9]. A continuation of this work resulted in the publication of decomposition rates for n-alkanes and mixtures of n-alkanes from C 9 to C 22 in a flowing tube reactor at atmospheric pressure and temperatures from 623 to 893 K [10].…”