Acetaldehyde paraffin oxidation

Technically, acetaldehyde is mainly made by the oxidation of ethylene using a CuCl2/PdCl2 catalyst system.. Although some acetic acid is still prepared by the catalytic oxidation of acetaldehyde, the main process is the catalytic oxidation of paraffins, usually -butane. 

A few plants have been built to oxidize normal paraffins such as propane and butane. Air and paraffin are charged to a tubular furnace at a temperature of about 700 R Acetaldehyde yields from butane are about 30—35%. 

As with ethane and other paraffin hydrocarbons, propane is an important raw material for the ethylene petrochemical industry. The decomposition of propane in hot tubes to form ethylene also yields another important product, propylene. The oxidation of propane to compounds such as acetaldehyde is also of commercial interest. 

Oxidations of paraffins with high concentrations of cobalt catalyst have very special characteristics. Such oxidations will proceed at lower temperatures than in the case of lower concentrations of cobalt or with other catalysts, or in the absence of catalysts [10, 18, 60-66]. For example, the high-concentration cobalt-ion oxidation of -butane can be conducted at 100-110 °C compared with 150-180 °C for the other cases. Significantly higher efficiencies to acetic acid are reported (75-84 % vs. about 50-60 %). Co-reductants such as acetaldehyde, MEK, or p-xylene (especially p-xylene [65]) are reported to be useful, but not essential [66]. In high-concentration cobalt-ion catalyzed oxidations, rates are generally lower than in the conventional oxidations. 

Oxidation ethylene, cumene, butane, toluene, xylene, ethylbenzene, acetaldehyde, cyclohexane, cyclohexene, n-paraffins, glucose vinyl acetate, phenol, acetone, methyl ethyl ketone, benzoic acid, phthalic acid, acetophenone, acetic acid, acetic anhydride cyclohexanol and cyclohexanone, adipic acid, sec-alcohols, glutonic acid... 

Supported metal oxides are currently being used in a large number of industrial applications. The oxidation of alkanes is a very interesting field, however, only until recently very little attention has been paid to the oxidation of ethane, the second most abundant paraffin (1). The production of ethylene or acetaldehyde from this feed stock is a challenging option. Vanadium oxide is an important element in the formulation of catalysts for selective cataljdic reactions (e. g. oxidation of o-xylene, 1-3, butadiene, methanol, CO, ammoxidation of hydrocarbons, selective catalytic reduction of NO and the partial oxidation of methane) (2-4). Many of the reactions involving vanadium oxide focus on the selective oxidation of hydrocarbons, and some studies have also examined the oxidation of ethane over vanadium oxide based catalysts (5-7) or reviewed the activity of vanadium oxide for the oxidation of lower alkanes (1). Our work focuses on determining the relevance of the specific oxide support and of the surface vanadia coverage on the nature and activity of the supported vanadia species for the oxidation of ethane. 

Acetaldehyde, together with many other oxygenated products, has been produced industrially by the vapor phase oxidation of paraffins such as butanes and propane/butane mixtures, or more generally from a light gasoline, according to a technology developed... 

Among paraffinic aldehydes, oxidation has been studied only for some straight chain derivatives, e.g. acetaldehyde, heptanal, decanal. We will deal with these cases one by one and attempt to describe the kinetic conclusions observed during thermal, photochemical, and catalytic oxidation. We will begin with decanal because the most quantitative thermal and photochemical oxidation results were obtained with this aldehyde. 

The photo-oxidation of SOa to S03T in the presence of H20 and Oa or NaO has been monitored by e.s.r.841 The photo-oxidation of carbon monoxide by oxygen may be catalysed by illumination of a number of inorganic oxides,842 and in another study it has been shown that the catalytic activity of ZnO for this reaction depends on the contact time of the catalyst with the gases prior to irradiation.843 Flash illumination of TiOz initiates the dehydrogenation of methanol or ethanol to formaldehyde and acetaldehyde, respectively.844 The oxidation of paraffins and olefins to ketones takes place on irradiation of Ti02 in the presence of these... 

Propane occupies an intermediate position between methane and ethane, which have no internal CH2 groups, and the other members of the paraffin series. The oxidation of propane at high pressures was studied in static [18,23] and flow [26] conditions. The data reported by Newitt (Tables 10.4 and 10.5) show that the products are acetaldehyde, propionic aldehyde, methanol, ethanol, propanol, and acetic acid, as well as small amounts of propionic and formic acids. 

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