Abstract: A method for determining the characteristic of one or more components in a step of an acetic acid production process using Raman spectroscopy. The process includes providing a feed stream comprising multiple components to a separations unit, one of the components being acetic acid, the separations unit separating the feed stream into two or more exit streams having a different composition from one another, and measuring a characteristic of one or more of the components by Raman spectroscopic analysis.

Abstract: Disclosed is a method for controlling a vinyl acetate production process. The method comprises reacting ethylene, acetic acid, and an oxygen-containing gas in the presence of a catalyst in a reactor to produce vinyl acetate, measuring the concentration of a component involved in or associated with the reaction and/or any of the subsequent steps by Raman spectroscopic analysis, and adjusting the conditions in the reactor or in any of the subsequent steps in response to the measured concentration of the component to achieve a proper control of the reaction or any of the subsequent steps.

Abstract: Disclosed is a method for controlling an acetic acid production process. The method comprises: (i) reacting methanol and carbon monoxide in the presence of a carbonylation catalyst, a catalyst stabilizer, methyl iodide, water, and methyl acetate to produce a reactor mixture which comprises the catalyst, the catalyst stabilizer, methanol, carbon monoxide, carbon dioxide, methyl iodide, methyl acetate, water, and acetic acid; (ii) measuring the concentration of a component of the reactor mixture by Raman spectroscopic analysis; and (iii) adjusting the component concentration in the reactor mixture in response to the measured concentration. The method of the invention is particularly useful for measuring and controlling the concentration of carbon monoxide in the reactor liquid mixture.

Abstract: The invention is a method of purifying acetic acid containing 15 to 100 ppb iodide compounds. The method comprises contacting the acetic acid in the liquid phase with a phosphine-functionalized support, and recovering a purified acetic acid product having 10 ppb, or less, iodide compounds.

Abstract: The invention is a method of removing methyl iodide from an alkane distillation bottoms stream of an acetic acid production process. The method comprises contacting the alkane distillation bottoms stream in the liquid phase with a phosphine or a phosphine-functionalized support, and recovering a treated alkane distillation bottoms stream having a reduced methyl iodide content.

Abstract: A method for removing hydrocarbon impurities from acetic acid is disclosed. The method comprises extracting acetic acid with a hydrophilic imidazolium salt. The imidazolium salt preferably has the general structure of wherein X? is a counter ion and R1, R2, R3, R4, and R5 are independently selected from the group consisting of C1-C6 hydrocarbon substitutes. The method is useful for removing hydrocarbon impurities from the alkane distillation bottoms stream of a methanol carbonylation process.

Abstract: A method for removing hydrocarbon impurities from acetic acid is disclosed. The method comprises extracting acetic acid with a hydrophilic imidazolium salt. The imidazolium salt preferably has the general structure of wherein X? is a counter ion and R1, R2, R3, R4, and R5 are independently selected from the group consisting of C1-C6 hydrocarbon substitutes. The method is useful for removing hydrocarbon impurities from the alkane distillation bottoms stream of a methanol carbonylation process.

Abstract: A method for removing hydrocarbon impurities from an acetic acid production process is disclosed. The method comprises distilling at least a portion of the heavy organic phase from the decanter of the acetic acid production process into a vapor stream comprising the majority of methyl iodide (i.e., over 50% of the methyl iodide from the heavy organic phase) and a bottoms stream comprising the majority of acetic acid, methyl acetate, methyl iodide and the hydrocarbon impurity (i.e., over 50% of each of the components from the heavy organic phase); extracting the bottoms stream with water, an acetic acid aqueous solution, or with a methanol aqueous solution to form an organic phase comprising the majority of the hydrocarbon impurity (over 50% of the hydrocarbon impurity from the bottom stream) and an aqueous phase comprising the majority of methyl iodide (over 50% of the methyl iodide from the bottoms stream); and recycling the aqueous phase to the carbonylation reaction.

Abstract: A method for removing hydrocarbon impurities from acetic acid is disclosed. The method comprises extracting acetic acid with a hydrophilic imidazolium salt. The imidazolium salt preferably has the general structure of wherein X? is a counter ion and R1, R2, R3, R4, and R5 are independently selected from the group consisting of C1-C6 hydrocarbon substitutes. The method is useful for removing hydrocarbon impurities from the alkane distillation bottoms stream of a methanol carbonylation process.

Abstract: A method for removing hydrocarbon impurities from an acetic acid production process is disclosed. The method comprises distilling at least a portion of the heavy organic phase from the decanter of the acetic acid production process into a vapor stream comprising the majority of methyl iodide (i.e., over 50% of the methyl iodide from the heavy organic phase) and a bottoms stream comprising the majority of acetic acid, methyl acetate, methyl iodide and the hydrocarbon impurity (i.e., over 50% of each of the components from the heavy organic phase); extracting the bottoms stream with water, an acetic acid aqueous solution, or with a methanol aqueous solution to form an organic phase comprising the majority of the hydrocarbon impurity (over 50% of the hydrocarbon impurity from the bottom stream) and an aqueous phase comprising the majority of methyl iodide (over 50% of the methyl iodide from the bottoms stream); and recycling the aqueous phase to the carbonylation reaction.

Abstract: Disclosed is a method for removing aldehyde impurities from a methyl acetate supply. The method comprises reacting the methyl acetate supply with a polyol and converting the aldehyde impurities to cyclic acetals. The acetals are subsequently removed from the methyl acetate supply by, e.g., distillation. The purified methyl acetate supply is used for carbonylation to produce acetic acid.

Abstract: A method for removing aldehyde impurities from acetic acid is disclosed. The method comprises extracting the aldehyde impurities from a methyl iodide solution such as the decanter heavy phase with a polyol. After the aldehyde impurities are removed, the methyl iodide heavy phase can be recycled to the carbonylation.