Borate-assisted liquid-phase selective oxidation of n-pentane

Abstract

Oxidation of n-pentane with molecular oxygen to sec-pentanols was performed in the presence of a free radical initiator (di-tert-butyl peroxide) and a boron compound (sec-butyl metaborate), with in situ adsorption of water on molecular sieve 3A. Kinetics of the reaction was studied in a laboratory-scale batch reactor over a broad range of conditions (130-150°C, 20-30 bar, 5-10 vol% O 2) in order to establish the optimum parameters for maximising the selectivity and yield of sec-pentanols. Results show that the initiator markedly improves the rate of oxidation, and hence yield, compared to thermal oxidation without an initiator, while the boron species enhances the selectivity to sec-pentanols. Under the conditions investigated, maximum secpentanol selectivity is 56% with an alcohol-to-ketone ratio of 3.6:1 for the borate-assisted oxidation compared to 33% and 1.1:1, respectively, for the oxidation without borate. This work demonstrates the feasibility of oxyfunctionalization of n-pentane with industrially relevant selectivity and yield.

The specific features of the liquid-phase oxidation of saturated esters. Kinetics, reactivity and mechanisms of formation of destruction products

“…Orthoboric acid esters were prepared in situ in the synthesis of secondary alcohols by oxidation of paraffi nic hydrocarbons according to the Bashkirov procedure to avoid their further oxidation. [90][91][92][93] The reactivity of the cyclohexyl moiety in the boric acid ester is lower than in cyclohexanol, but somewhat higher than in cyclohexyl acetate (see Table 2). 84…”

Multi-objective Bayesian optimisation of a two-step synthesis of p-cymene from crude sulphate turpentine

“…The internal packing of the reactor is an efficient radical scavenger, whereas the micro-heat exchanger has previously been shown to be highly efficient in elevated temperature selective oxidation reactions (Bavykin et al, 2005). We hypothesised that the addition of a radical initiator may enhance the reaction rate, especially at short residence times; this is based on our previous work on aerobic oxidation in the liquid phase (Aworinde et al, 2018).…”