Cleaner technology for the production of linear long-chain α-olefins through a “millisecond” oxidative cracking process: a positive impact of the reactant carbon chain length

Abstract

The oxidative cracking of n-decane, n-dodecane, n-tetradecane and n-hexadecane was assessed at millisecond contact times on a platinum catalyst at a C/O molar ratio of 1.8. The thermal mapping of the reactor showed the similar thermal behaviour of the millisecond reactor at the steady-state for all reactants, corresponding to the autothermal operation of the combustion catalyst in the range of 440–550 °C. The heat provided led to a thermal gradient in the post-catalytic gas-phase and sustained the endothermic formation of valuable linear α-olefins (LAOs). The LAO yields increased with the carbon chain length of the reactant from 11.4 wt% starting from n-decane to 20.2 wt% starting from n-hexadecane. Furthermore, the LAO carbon chain length tends to be higher when feeding the MSR with larger n-alkanes. Two mathematical models are able to predict the distributions of organic products: (i) the Anderson-Schultz-Flory law for cracking products, i.e. LAO and n-aldehydes and (ii) a model based on the hydrogen atom abstraction probability for oxygenated compounds, the formation of which does not involve carbon–carbon bond cleavage, i.e. tetrahydrofurans, oxiranes and ketones.