The present disclosures and inventions relate to methods for the preparation of acetic acid via the oxidation of ethane, including the preparation of high purity acetic acid that comprises very low concentrations of formic acid impurity. More specifically, described herein are methods for producing acetic acid comprising: a. producing a crude acetic acid composition comprising formic acid from ethane via ethane oxidation; and then b. purifying the crude acetic acid composition by crystallization to remove formic acid to achieve a purified acetic acid composition; wherein the formic acid is present in the purified acetic acid composition in an amount less than 0.2% by weight, based on the total weight of the purified acetic acid composition.

The present disclosures and inventions relate to methods for the preparation of acetic acid via the oxidation of ethane, including the preparation of high purity acetic acid that comprises very low concentrations of formic acid impurity. More specifically, described herein are methods for producing acetic acid comprising: a. producing a crude acetic acid composition comprising formic acid from ethane via ethane oxidation; and then b. purifying the crude acetic acid composition by crystallization to remove formic acid to achieve a purified acetic acid composition; wherein the formic acid is present in the purified acetic acid composition in an amount less than 0.2% by weight, based on the total weight of the purified acetic acid composition.

The present invention concerns a process for the recovery of carboxylic acid from a fraction comprising carboxylic acid and impurities, and a process for the manufacture of treated wood, which comprise the step of submitting a fraction containing carboxylic acid and impurities to a gas stripping operation.

The present invention concerns a process for the recovery of carboxylic acid from a fraction comprising carboxylic acid and impurities, and a process for the manufacture of treated wood, which comprise the step of submitting a fraction containing carboxylic acid and impurities to a gas stripping operation.

This invention relates to a method for the conversion of lignocellulosic biomass into ethyl esters of carboxylic acids. Said method consists of treating the biomass material with an oxidizing agent that is incorporated in an solution comprising one or more acids, one or more alcohols and water, and subsequently performing a catalytic reaction at a higher temperature using the same acidic solution into which a larger volume of alcohol is added, in such a way that the catalytic conversion occurs in a medium with a much higher concentration of alcohol, i.e. with a much higher alcohol-to-water wt ratio. Such a method results in relatively high yields of ethyl esters, such as ethyl esters of formic, acetic, and levulinic acids, while producing a low yield of dialkyl ethers, which are unwanted by-products. The concentration of the oxidizing agent in the pre-treatment step is preferably higher than 6.0 wt %. The oxidizing agent is preferably a Fenton or Fenton-type reagent, and most preferably hydrogen peroxide activated by Fe (II), and/or Ti (IV) ions. The alcohol is preferably ethanol, and when ethanol is used, diethyl ether is formed as the unwanted dialkyl ether by-product. Preferably, the biomass material is pelleted before treatment.

This invention relates to a method for the conversion of lignocellulosic biomass into ethyl esters of carboxylic acids. Said method consists of treating the biomass material with an oxidizing agent that is incorporated in an solution comprising one or more acids, one or more alcohols and water, and subsequently performing a catalytic reaction at a higher temperature using the same acidic solution into which a larger volume of alcohol is added, in such a way that the catalytic conversion occurs in a medium with a much higher concentration of alcohol, i.e. with a much higher alcohol-to-water wt ratio. Such a method results in relatively high yields of ethyl esters, such as ethyl esters of formic, acetic, and levulinic acids, while producing a low yield of dialkyl ethers, which are unwanted by-products. The concentration of the oxidizing agent in the pre-treatment step is preferably higher than 6.0 wt %. The oxidizing agent is preferably a Fenton or Fenton-type reagent, and most preferably hydrogen peroxide activated by Fe (II), and/or Ti (IV) ions. The alcohol is preferably ethanol, and when ethanol is used, diethyl ether is formed as the unwanted dialkyl ether by-product. Preferably, the biomass material is pelleted before treatment.

A method for producing acetic acid includes subjecting an acetic acid solution to an acetic anhydride decreasing treatment. The acetic acid solution is present typically in, or downstream from, a distillation column (5) of acetic acid production equipment (X), includes acetic acid in a concentration of 90 mass percent or more, acetic anhydride, and water, and is in such a state that an equilibrium concentration of acetic anhydride is higher than an acetic anhydride concentration. The acetic anhydride decreasing treatment includes at least one of water concentration increasing and temperature lowering so as to bring the acetic acid solution into such a state that the equilibrium concentration of acetic anhydride is lower than the acetic anhydride concentration. The acetic acid production method is suitable for yielding a high-purity acetic acid product.

A method for producing acetic acid includes subjecting an acetic acid solution to an acetic anhydride decreasing treatment. The acetic acid solution is present typically in, or downstream from, a distillation column (5) of acetic acid production equipment (X), includes acetic acid in a concentration of 90 mass percent or more, acetic anhydride, and water, and is in such a state that an equilibrium concentration of acetic anhydride is higher than an acetic anhydride concentration. The acetic anhydride decreasing treatment includes at least one of water concentration increasing and temperature lowering so as to bring the acetic acid solution into such a state that the equilibrium concentration of acetic anhydride is lower than the acetic anhydride concentration. The acetic acid production method is suitable for yielding a high-purity acetic acid product.

The present invention discloses pharmaceutical-grade ferric organic compounds, including ferric citrate, which are soluble over a wider range of pH, and which have a large active surface area. A manufacturing and quality control process for making a pharmaceutical-grade ferric citrate that consistently complies with the established Manufacture Release Specification is also disclosed. The pharmaceutical-grade ferric organic compounds are suitable for treating disorders characterized by elevated serum phosphate levels.

The present invention discloses pharmaceutical-grade ferric organic compounds, including ferric citrate, which are soluble over a wider range of pH, and which have a large active surface area. A manufacturing and quality control process for making a pharmaceutical-grade ferric citrate that consistently complies with the established Manufacture Release Specification is also disclosed. The pharmaceutical-grade ferric organic compounds are suitable for treating disorders characterized by elevated serum phosphate levels.