Abstract: A low energy process for producing acetic acid by the carbonylation of methanol is disclosed. The process involves a rhodium-catalyzed system operated at less than about 14% water utilizing up to 2 distillation columns. The process is preferably controlled such that the product stream has a low level of propionic acid impurity and the level of aldehyde impurities is minimized by way of aldehyde removal or minimizing aldehyde generation. The level of iodides is controlled by contacting the product, at elevated temperatures, with ion exchange resins. In preferred embodiments, at least one silver or mercury exchanged macroreticular strong acid ion exchange resin is used to purify the product. The high temperature treatment provides the added benefit of controlling the Color Value (Pt—Co units) of the product stream.

Abstract: A low energy process for producing acetic acid by the carbonylation of methanol is disclosed. The process involves a rhodium-catalyzed system operated at less than about 14% water utilizing up to 2 distillation columns. The process is preferably controlled such that the product stream has a low level of propionic acid impurity and the level of aldehyde impurities is minimized by way of aldehyde removal or minimizing aldehyde generation. The level of iodides is controlled by contacting the product, at elevated temperatures, with ion exchange resins. In preferred embodiments, at least one silver or mercury exchanged macroreticular strong acid ion exchange resin is used to purify the product. The high temperature treatment provides the added benefit of controlling the Color Value (Pt—Co units) of the product stream.

Abstract: Disclosed is a method to manufacture high purity acetic acid. Although described in relation to that produced by a low water carbonylation process the present invention is applicable to other mechanisms for production of acetic acid which results in formation of permanganate reducing compounds such as acetaldehyde and its derivatives, and alkyl iodide impurities in intermediate process streams. It has been found that permanganate reducing compounds and alkyl iodides may be conveniently removed from a light phase of an intermediate stream in the reaction process by employing a multiple distillation process coupled with an optional post extraction of acetaldehyde. The distillation process involves first distilling a light phase to concentrate the permanganate reducing compounds, and in particular the acetaldehyde, and then separating the permanganate reducing compounds and alkyl iodides in a second distillation tower.

Abstract: A process for electrochemical oxidation of aldehydes to esters is provided. The invention includes electrooxidation at a pH where an intermediate hemiacetal is favored, thereby providing for maximum selectivity to the desired ester and for maximum reaction efficiency. In particular, the invention provides for the electrooxidation of acetaldehyde to methyl acetate. The invention is illustrated with reference reactants native to the carbonylation process for the manufacture of acetic acid. Processes described herein are readily adapted to an industrial scale, particularly for the removal of acetaldehyde from process streams.

Abstract: A method of removing organic iodides from non-aqueous organic media includes contacting the organic media with a silver or mercury-exchanged cationic ion exchange substrate at a temperature greater than about 50° C. The method is particularly effective for removing high molecular weight organic iodides from organic media such as acetic acid or acetic anhydride. Particular species removed include decyl iodides and dodecyl iodides from organic media such as acetic acid.

Abstract: Disclosed is a method to manufacture high purity acetic acid. Although described in relation to that produced by a low water carbonylation process the present invention is applicable to other mechanisms for production of acetic acid which results in formation of permanganate reducing compounds such as acetaldehyde, propionic acid, and alkyl iodide impurities in intermediate process streams. It has been found that permanganate reducing compounds and alkyl iodides may be conveniently removed from a light phase of an intermediate stream in the reaction process by employing a multiple distillation process coupled with an optional extraction of acetaldehyde. The distillation process involves first distilling a light phase to concentrate the permanganate reducing compounds, and in particular the acetaldehyde, and then separating the permanganate reducing compounds and alkyl iodides in a second distillation tower.

Abstract: The present invention provides a process for preparing arylglyoxals which comprise the steps of (a) electrochemically oxidizing an arylketone at a pH of less than about seven and at a temperature of from about -20.degree. C. to about 120.degree. C. in the presence of an electrolyte for a sufficient period of time to form an arylacetal, and (b) subjecting said acetal to hydrolysis for a sufficient period of time and under suitable temperature and pressure conditions to form said arylglyoxal.

Abstract: The present invention provides a process for preparing arylglyoxals which comprise the steps of (a) electrochemically oxidizing an arylketone at a pH of less than about seven and at a temperature of from about -20.degree. C. to about 120.degree. C. in the presence of an electrolyte for a sufficient period of time to form an arylacetal, and (b) subjecting said acetal to hydrolysis for a sufficient period of time and under suitable temperature and pressure conditions to form said arylglyoxal.

Abstract: A method is provided to improve the quality of recycle of certain residues by modifying the separation of alkanes and alkane-like materials and carbonyl-containing impurities from the recycle during the manufacture of acetic acid by the carbonylation of methanol. The improvement comprises operating a prior art stripper column in a reflux manner and partitioning the residue therefrom by the addition of water. The method also reduces the volume of disposal of potentially valuable recyclable reactants.

Abstract: A method is provided for purifying a crude N-acetyl-para-aminophenol (APAP) containing color bodies or their precursors, the method comprising: a) forming a wet crude APAP; and b) subsequently drying said crude APAP in the presence of a sufficient amount of an acetylating agent for a sufficient period of time to convert said color bodies or their precursors to substantially non-color bodies.

Abstract: In the operation of a recycling anaerobic filter for treating aqueous waste streams, the rate of production of methane is measured continually at frequent intervals and the COD feed rate is varied to maintain a predetermined, timed, relationship between that varied feed rate and the measured methane production rate.

Abstract: In the operation of a recycling anaerobic filter for treating aqueous waste streams, the rate of production of methane is measured continually at frequent intervals and the COD feed rate is varied to maintain a predetermined, timed, relationship between that varied feed rate and the measured methane production rate.

Abstract: The fouling of electrodes of pH meters used in anaerobic bacteria digestion processes may be prevented by intermittently immersing the electrodes in an aqueous bactericidal solution, which bactericidal solution is preferably buffered to a known pH. While immersed in such a buffered bactericidal solution, there is simultaneously accomplished the killing of the bacteria accumulated on the electrode and the calibration of the pH meter.

Abstract: A process for dehalogenation of alpha halogenated carbonyl compounds and/or the prevention of the formation of such. The process for dehalogenation generally comprises causing there to be in solution the halogenated compound, cuprous ions (such as from cuprous chloride) and hydrogen ions (such as from hydrochloric acid), the process to be conducted in the absence of molecular oxygen, or, if molecular oxygen is present, there being an excess of cuprous ions sufficient to completely react with the molecular oxygen present. The present method can also be used to suppress formation of halogenated carbonyl compounds in processes where conditions exist which favor such formation.

Abstract: The data derived from a computerized axial tomographic apparatus in respect of a number of slices through a body are processed to produce a representation of the variation of absorption of X-rays over each slice. The representations are operated upon individually to identify areas which are of reduced interest and/or which are obscuring regions of especial interest. This having been done, the representations for all the slices are correlated to produce a pseudo three-dimensional display of part of the body with the identified areas being displayed with reduced or zero intensity as compared with other areas. Alternatively, the identified and other areas can be represented in different colors.