The synthesis of acetic acid from methane via oxidative bromination, carbonylation, and hydrolysis

The Oxidative Bromination of Methane Over Rh/SiO2 Catalyst

“…In acetic acid synthesis, CH 4 was converted to the intermediates CH 3 Br and CO in the first reaction, and then CH 3 Br and CO were converted to acetic acid in the consecutive reactions. Hence, in acetic acid synthesis, CH 3 Br and CO are the desired products of the OBM reaction [10,11]. Generally, the hydrogen halides (HCl and HBr) involved reactions are understood as halogen radical reactions.…”

“…However, the oxidative chlorination of methane (HCl as chlorination agent) rather than the oxidative bromination of methane (OBM) was employed for the illustration in the patent. In our previous investigation, higher hydrocarbons [8], dimethyl ether [9], and acetic acid [10,11] were synthesized through HBr mediated reactions. In all of these processes, high methane conversion and product selectivities were reached.…”

“…The oxidative bromination of alkanes as an alternative approach for light alkane conversion was investigated in recent years [1][2][3][4][5][6][7][8][9][10][11][12]. In Schweizer et al's patent [13], a process was described to halogenate CH 4 to CH 3 X (X is halogen), and then convert CH 3 X to higher hydrocarbons or acetic acid.…”

Acetic Acid from the Carbonylation of Chloride Methane Over Rhodium Based Catalysts

“…In the next 6 h, although the acetic acid yield still increases, the reaction rate slowed down. Significantly, an acetic acid yield of 77.2% was obtained at 8 h. The yield of acetic acid leveled off after reaction time longer than 8 h. It was reported that there is an induction period in bromide methane carbonylation reaction over a rhodium catalyst, but the induction period can be eliminated by the addition of a sufficient amount of phosphine [14]. In our experiment, no obvious induction time was observed, possibly implies that the amount of phosphine and iodide promoters used in our system was sufficient.…”

“…Nowadays more than 60% of the industrial production of acetic acid is obtained by the carbonylation of methanol [12], which is produced from syngas feedstock with Cu/ZnO/Al 2 O 3 catalysts at 220-300°C and 5-10 MPa [13]. It has been reported that methyl bromide can be carbonylated by carbon monoxide over rhodium-based catalyst to produce acetic acid [14]. The possibility of acetic acid production using carbonylation of methyl chloride has been discussed [15], although it was believed to be not easily realized [16,17].…”