Abstract: The invention relates to a process for the production of acetic acid by carbonylation of methanol, and reactive derivatives thereof, in a reaction mixture using a rhodium-based catalyst in low water conditions. The process is used to achieve reaction rates of at least 15 g mol/l/hr. The high rate reactions proceed at water concentrations of less than 2.0 wt. %. Under certain conditions, the water concentration in the reaction mixture of the process is maintained at a desired concentration by at least one process step including adding a compound such as methyl acetate, dimethyl ether, acetic anhydride, or mixtures of these compounds to the reaction system. The process step of adding the components to the reaction mixture may be combined with other process steps for controlling water concentrations in reaction mixtures for the carbonylation of methanol.

Abstract: The invention relates to a process for the production of acetic acid by carbonylation of methanol, and reactive derivatives thereof, in a reaction mixture using a rhodium-based catalyst in low water conditions. The process is used to achieve reaction rates of at least 15 g mol/l/hr. The high rate reactions proceed at water concentrations of less than 2.0 wt. %. Under certain conditions, the water concentration in the reaction mixture of the process is maintained at a desired concentration by at least one process step including adding a compound such as methyl acetate, dimethyl ether, acetic anhydride, or mixtures of these compounds to the reaction system. The process step of adding the components to the reaction mixture may be combined with other process steps for controlling water concentrations in reaction mixtures for the carbonylation of methanol.

Abstract: A process for monitoring and controlling reactor conditions during the production of acetic acid by the catalyzed carbonylation of methanol is provided. The process of the present invention comprises measuring the density of the heavy phase of the light ends distillation column in the purification system of the carbonylation process. The density measurement is used to adjust the feed of methanol and/or to regulate the temperature in the reaction zone to optimize reactor conditions. The density measurement may also be used to adjust other parameters in the reactor system. The invention is also directed to the system for manufacturing acetic acid based on the process control procedure described.

Abstract: A method and system is provided for producing acetic acid by the catalytic carbonylation of methanol with carbon monoxide to obtain a reaction product stream comprising acetic acid and a minor amount of acetaldehyde. The acetaldehyde content in the reaction product stream is reduced by oxidation to convert at least a portion of the acetaldehyde in the stream to acetic acid or further to CO2 and H2O. The oxidized stream may then be directed to the purification section, the reaction section, or both whereby the deleterious effects of acetaldehyde are reduced. Advantage of the present invention over conventional processes is the reduced need to dispose of acetaldehyde as waste and improved overall system efficiency in the production of acetic acid.

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 method and system is provided for producing acetic acid by the catalytic carbonylation of methanol with carbon monoxide to obtain a reaction product stream comprising acetic acid and a minor amount of acetaldehyde. The acetaldehyde content in the reaction product stream is reduced by oxidation to convert at least a portion of the acetaldehyde in the stream to acetic acid or further to CO2 and H2O. The oxidized stream may then be directed to the purification section, the reaction section, or both whereby the deleterious effects of acetaldehyde are reduced. Advantage of the present invention over conventional processes is the reduced need to dispose of acetaldehyde as waste and improved overall system efficiency in the production of acetic acid.

Abstract: A method and apparatus for sequestering entrained or volatile catalyst species in a carbonylation process includes contacting the product stream with a vinyl pyridine or a vinyl pyrrolidone resin bed which is operative to sequester entrained or volatile catalytic species. The invention is particularly useful in connection with the iridium catalyzed carbonylation of methanol wherein the loss of entrained or volatile catalyst species depletes the catalytic content of the reactor. The resin may be digested in order to recover the catalytic metals.

Abstract: A process for monitoring and controlling reactor conditions during the production of acetic acid by the catalyzed carbonylation of methanol is provided. The process of the present invention comprises measuring the density of the heavy phase of the light ends distillation column in the purification system of the carbonylation process. The density measurement is used to adjust the feed of methanol and/or to regulate the temperature in the reaction zone to optimize reactor conditions. The density measurement may also be used to adjust other parameters in the reactor system. The invention is also directed to the system for manufacturing acetic acid based on the process control procedure described.

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: The method of the present invention provides an improvement upon prior art methanol carbonylation methods which substantially reduces the production of carbonyl impurities. The production of carbonyl impurities, particularly acetaldehyde, crotonaldehyde, and 2-ethyl crotonaldehyde, in methanol carbonylation reactions has been found to decrease by maintaining a partial pressure of hydrogen between about 0.1 and 4 psia at reaction total pressure of from about 15 to about 40 atmospheres total reaction pressure.

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: The present invention provides a process for the carbonylation of an alcohol, ether or ester to products comprising a carboxylic acid, the anhydride thereof or coproduction of the carboxylic acid and anhydride. More particularly, the present invention provides a process for the carbonylation of methanol to produce acetic acid by reacting methanol with carbon monoxide in a liquid reaction medium containing a catalyst comprising rhodium, iridium, iodide ion, and said reaction medium further comprising water, acetic acid, methyl iodide, and methyl acetate and subsequently recovering acetic acid from the resulting reaction product.

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: A process to reduce carbonyl impurities in a carbonylation reaction for the production of acetic acid is described. The methyl iodide recycle stream which is directed to a carbonylation reactor for carbonylating methanol or methyl acetate to acetic acid, is treated to remove carbonyl impurities by reacting the methyl iodide stream formed in the reaction with an aqueous amino compound which reacts with the carbonyls to form water soluble nitrogenous derivatives, separating an organic methyl iodide phase from an aqueous derivative phase and distilling the methyl iodide phase to remove heavier impurities. The treatment of the methyl iodide recycle stream to the carbonylation reactor has been found to greatly reduce the carbonyls present in the acetic acid product. The formation of nitrile from the nitrogenous derivative during distillation may be minimized by adding water to the system.

Abstract: A carbonylation catalyst useful for the carbonylation of methanol to acetic acid, acetic anhydride or both comprises a polymer support containing pendant pyrrolidone groups which support a rhodium species. Other polymeric supports capable of withstanding carbonylation temperatures of at least 150.degree. C. are disclosed for the carbonylation reaction in which rhodium levels in the reaction medium of greater than 500 ppm are contemplated.

Abstract: A method is provided for removing iodide compounds, particularly alkyl iodide compounds, from iodine-containing liquids, particularly carboxylic acids and anhydrides manufactured by the carbonylation of alcohols, ethers, esters, and the like in the presence of a rhodium catalyst and an alkali metal or alkaline earth metal salt, particularly a lithium salt, wherein the carboxylic acid or anhydride is contacted with a silver or mercury salt coordinated to a polymeric resin containing functional groups having the capability to quaternize with or form ionic salts with the alkyl halides.

Abstract: A carbonylation catalyst useful for the carbonylation of methanol to acetic acid, acetic anhydride or both comprises a polymer support containing pendant pyrrolidone groups which support a rhodium species. Other polymeric supports capable of withstanding carbonylation temperatures of at least 150.degree. C. are disclosed for the carbonylation reaction in which rhodium levels in the reaction medium of greater than 500 ppm are contemplated.

Abstract: Esters such as methyl acetate which contain carbonyl impurities including aldehydes are purified by adding to the esters an amino compound which reacts with the carbonyls to form water soluble nitrogenous derivatives, separating an organic ester phase from an aqueous derivative phase, and distilling the ester phase to further remove heavier impurities. The formation of nitrile from the nitrogenous derivative is minimized by adding water to the distillation column or washing the aqueous bottoms from distillation with water to further remove the derivatives from any ester contained in the bottoms. The organic phase recovered from the bottoms can be recycled to the distillation to recover ester.

Abstract: Acetic acid produced by the low water carbonylation of methanol and containing iodide, unsaturates and carbonyl impurities is purified by treatment with ozone.