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Acetic Acid Production by Ethane and Methane Oxidation

The search for acetic acid production processes with even lower raw material costs has led to attempts to produce it by methane and ethane oxidation processes. [Pg.748]

Direct oxidation from ethane [Eq. (6.15.10)] was intensively studied in the 1980s  [Pg.748]

The work was strongly inspired by Union Carbide s Ethoxene process, a route for manufacturing ethylene from ethane and oxygen by oxidative dehydrogenation. The first catalysts consisted of molybdenum, vanadium, and niobium oxides. The selectivity for ethylene was very high but, unfortunately, the conversion of ethane was low ( 10%). Therefore, scientists at the time focused on the co-production of ethylene and acetic acid. A catalyst consisting of molybdenum, vanadium, niobium, calcium, and antimony supported on a molecular sieve was developed (63% selectivity to acetic acid, 14% selectivity to ethylene, and 3% conversion of ethane). In addition, Rhone-Poulenc (catalyst vanadium oxide or vanadyl pyrophosphate) and BP (catalyst combination of rhenium and tungsten) patented processes for the production of acetic acid from ethane. Very efficient catalysts were also disclosed by Hoechst (molybdenum vanadate, promoted with Nb, Sb, Ca, and Pd, 250-280 °C, 15 bar, 86% selectivity to acetic add at 11% conversion of ethane per pass) and Sabic (phosphorus-modified molybdenum-niobium vanadate, 260 °C, 14 bar, 50% selectivity to acetic acid at 53% conversion of ethane). [Pg.748]

In the near future ethane oxidation will most likely not compete with methanol carbonylation (even though ethane is a very cheap and attractive raw material) because of the low ethane conversions and product inhibition problems. In addition, the large variety of by-products and the need to work with water as additive (resulting again in high costs for the purification of the acetic add) still prevent the commerdaUzation of this route. [Pg.748]

An even cheaper feedstock than ethane is methane. A direct reaction from methane to acetic acid requires first methane oxidation to methanol followed by a carbonylation step. Catalyst systems based on Pd/Cu or RhCls have been reported to show good acetic acid jdelds in academic work, but for a commerdal process the reaction rates are still too slow. Nevertheless, due to the very attractive feedstock basis this route may become a threat to methanol carbonylation in the future if this problem can be convincingly overcome by further process and catalyst development. [Pg.748]




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Acetalization-oxidation

Acetals oxidation

Acetate oxidation

Acetate production

Acetic acid and acetates

Acetic acid production

Acetic oxide

Acidic by-products

Acids and Oxidizers

By acetic acid

Ethan acid

Ethanal acidity

Ethane Oxidation products

Ethane acetic acid

Ethane acidity

Ethane production

Methanal oxidation

Methane + ethane

Methane acetates

Methane acetic acid

Methane acidity

Methane production

Oxidation by-products

Oxidative methane

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