One problem with the original Monsanto process is that a large amount of water (about 14%) is needed to produce hydrogen in the reactor via the water-gas shift reaction (CO+H2OCO2+H2). The carbonylation reaction is performed in the presence of water. Contents. Preferably, the concentration of methyl iodide is from about 0.6 wt % to about 36 wt % based on the total weight of the reaction medium. Phosphine oxides are more preferred. New methods for reducing aldehydes in acetic acid are needed. Furthermore, the use of iodide salts increases the iodide impurities in the acetic acid product. Methanol does not react directly with carbon monoxide to form acetic acid. Preferred co-catalysts include metals and metal compounds selected from the group consisting of osmium, rhenium, ruthenium, cadmium, mercury, zinc, gallium, indium, and tungsten, their compounds, the like, and mixtures thereof. The iridium catalyst is preferably used with a co-catalyst. More preferably, about 5% to about 50% of the heavy, organic phase is reacted with acetic anhydride. The process comprises reacting a stream of an acetic acid production process, which comprises methyl iodide and acetaldehyde, for instance, the decanter heavy, organic phase, with acetic anhydride to convert acetaldehyde to ethylidene diacetate and separating it from the stream. It does not reduce Tollen’s reagent but forms an addition compound with sodium hydrogensulphite and give positive iodoform test. More preferred co-catalysts are selected from the group consisting of ruthenium compounds and osmium compounds. Methanol and carbon monoxide are fed to the carbonylation reactor. Fig. More specifically, the reaction is effected at temperatures of 62 to 90.degree.C over a period of less than 20 minutes with the use of the diluent and acetaldehyde in a quantitative ratio of 60:40 to 40:60; the resulting reaction products are delivered to a distilling zone in which the carboxylic acid ester and water are distilled off overhead and separated into two phases. 309604777 - EP 0049863 A1 19820421 - Process for the preparation of acetic acid, acetaldehyde and ethanol from synthesis gas. Preferably, the concentration of hydrogen is from about 0.1 mol % to about 5 mol % of carbon monoxide in the reactor. As the first drop of the solution is eluting from the column, the syringe pump containing the acetic anhydride is turned at rate of 6.5 mL/hr. On vigorous oxidation it gives ethanoic and propanoic acid. Hydrogen may also be fed into the reactor. However, the dioxanes are stable and the glycols thus cannot be easily recovered. More preferably, the concentration of methyl iodide is from about 4 wt % to about 24 wt %. The acetic acid stream may be passed to a drying column to remove water and then be subjected to the so called “heavy ends distillation” to remove the heavy impurities. Preferably, the reaction of the heavy, organic phase with acetic anhydride is performed at a temperature within the range of about 20° C. to about 135° C. More preferably, the temperature is within the range of about 20° C. to about 50° C. Preferably, the treatment is performed in the presence of an acid catalyst. However, the high concentration of lithium iodide salt promotes stress crack corrosion of the reactor vessels. You can use Global Patent Index (GPI) to carry out detailed searches in the EPO's worldwide bibliographic (DOCDB), legal event (INPADOC) and full-text data sets, and download or visualise the search results for statistical analysis. Privacy Policy The invention relates to a process for removing acetaldehyde from the acetic acid production process. This method is further divided into two separate methods. The invention relates to the preparation of acetic acid. The overhead is condensed and separated in a decanter to a light, aqueous phase and a heavy, organic phase. In general, there are two types of catalyst stabilizers. 1a shows that as the temperature increases, the selectivity for acetaldehyde decreases, whereas that for acetic acid increases.Thus, acetaldehyde might be an intermediate of acetic acid generation. No. Next, the organic phase is recycled with a reflux ratio of at least 1:1 to the distilling zone; base product accumulating in the distilling zone is delivered to an evaporating zone in which 2 to 12 parts by weight of an acetic acid/acetic anhydride-mixture as distillate are produced per part by weight of catalyst solution as base product.

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