A novel salt of treprostinil and methods of its preparation and use are disclosed.

Disclosed herein is a method and apparatus for synthesizing co-crystals from the vapor phase without the need for liquid solvent. Also disclosed herein are co-crystals formed from the vapor phase, substrates coated with said co-crystals, pharmaceutical compositions thereof and apparatuses for producing said co-crystals.

Disclosed herein is a method and apparatus for synthesizing co-crystals from the vapor phase without the need for liquid solvent. Also disclosed herein are co-crystals formed from the vapor phase, substrates coated with said co-crystals, pharmaceutical compositions thereof and apparatuses for producing said co-crystals.

A method of production of malic acid includes treating a first intermediate product to form a second intermediate product. The treating includes substantially removing impurities from the first intermediate product to obtain a treated intermediate product by gas stripping the crude maleic anhydride, or subjecting a mixture of one or more of the crude maleic acid, the crude fumaric acid, and the vent gas scrubber solution obtained from a phthalic anhydride production process or a maleic anhydride production process to crystallization, passing an aqueous solution of the treated intermediate product through a carbon column to substantially remove retained impurities to form the second intermediate product, obtaining a feed that includes the second intermediate product, and causing the feed to undergo hydration reaction in a tubular reactor or a continuous stirred tank reactor to produce malic acid.

A method of production of malic acid includes treating a first intermediate product to form a second intermediate product. The treating includes substantially removing impurities from the first intermediate product to obtain a treated intermediate product by gas stripping the crude maleic anhydride, or subjecting a mixture of one or more of the crude maleic acid, the crude fumaric acid, and the vent gas scrubber solution obtained from a phthalic anhydride production process or a maleic anhydride production process to crystallization, passing an aqueous solution of the treated intermediate product through a carbon column to substantially remove retained impurities to form the second intermediate product, obtaining a feed that includes the second intermediate product, and causing the feed to undergo hydration reaction in a tubular reactor or a continuous stirred tank reactor to produce malic acid.

The present invention discloses a method for recycling urea in the process of separating and purifying unsaturated substances through a urea adduction method. The method comprises the following steps: liposoluble substances containing target unsaturated components are used as raw materials, and subjected to urea adduction, crystallization and filtration to produce a filtrate, from which the specific unsaturated components are obtained; the urea adduct is dissolved in a polar solvent, and after the adducted adducts are layered and released, adding a certain solvent to the urea solution to adjust the polarity, then cooling for crystallization, and recycling the urea. The method can realize complete release of the adducted components and recycling and reuse of urea, and the process is simple, the recovery rate is high, and the adduction effect is not influenced when recycling urea for reuse, and the production cost of the urea adduct is reduced, thus alleviating the adverse impact of urea discharges on the environment.

The present invention discloses a method for recycling urea in the process of separating and purifying unsaturated substances through a urea adduction method. The method comprises the following steps: liposoluble substances containing target unsaturated components are used as raw materials, and subjected to urea adduction, crystallization and filtration to produce a filtrate, from which the specific unsaturated components are obtained; the urea adduct is dissolved in a polar solvent, and after the adducted adducts are layered and released, adding a certain solvent to the urea solution to adjust the polarity, then cooling for crystallization, and recycling the urea. The method can realize complete release of the adducted components and recycling and reuse of urea, and the process is simple, the recovery rate is high, and the adduction effect is not influenced when recycling urea for reuse, and the production cost of the urea adduct is reduced, thus alleviating the adverse impact of urea discharges on the environment.

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 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.