A process is provided for obtaining high-purity valine in high yield by a simple method using an inexpensive precipitant of p-isopropylbenzene sulfonic acid or a water-soluble salt thereof.

In the process, used sulfuric acid which contains, as minor constituents, methylsulfuric acid, dimethyl ether, methanol, aliphatic and olefinic hydrocarbons, chlorinated hydrocarbons and oligomeric siloxanes, in a first step; (1) used sulfuric acid is diluted by introducing steam and optionally by adding liquid water to a concentration of at most 55% by weight sulfuric acid and is heated to boiling at a maximum of 135.degree. C. and in a second step; (2) the sulfuric acid from the first step is ...

A carboxylated latex is added to an aqueous slurry of fibers to remove metal ions contained in solution. The water is removed to form a felt. The demetallized water removed during felt formation is recycled in a closed process water system. The carboxylated latex is formed by polymerizing an unsaturated carboxylic acid on a substantially surfactant free styrene-diene polymer latex.

A mixture containing monochloroacetic acid and dichloroacetic acid as the main components are admixed with 5-25% by weight of water on the basis of sum total of monochloroacetic acid, dichloroacetic acid and water, and subjected to adiabatic cooling under a pressure of 133 to 2,660 Pa, whereby monochloroacetic acid is crystallized with a high purity.

Process for removing biorefractory compounds from contaminated water (e.g., oil shale retort waste-water) by contacting same with fragmented raw oil shale. Biorefractory removal is enhanced by preactivating the oil shale with at least one member of the group of carboxylic, acids, alcohols, aldehydes, ketones, ethers, amines, amides, sulfoxides, mixed ether-esters and nitriles. Further purification is obtained by stripping, followed by biodegradation and removal of the cells.

The invention relates to a method for purifying water by forming in an electrolytic cell molecular halogen, hypohalic acid, hypohalite ions or combinations thereof, from halide ions dissolved in the water; and dissolving one or more soluble metal salts in the water to provide corresponding metal ions. The invention also relates to a system for purifying water, having an electrolytic cell comprising a plurality of electrodes sufficient to electrolytically convert halide ion in the water into mole...

A method is disclosed to purify a polymeric material by filtering a melt comprising poly(arylene ether) and poly(alkenyl aromatic) through a melt filtration system. The method provides a polymeric material having reduced levels of particulate impurities. The polymeric material prepared is suitable for use in data storage media applications.

An exhaust gas purifying system of the present invention comprises a first catalyst which contains a noble metal and reduces hydrocarbons contained in exhaust gas, and a second catalyst which is disposed downstream of the first catalyst and contains .beta.-zeolite. In the exhaust gas purifying system, a mixed gas having an air-fuel ratio of not less than 25 is burned in an internal combustion engine, and the internal combustion engine discharges the exhaust gas having an oxygen concentration of ...

The present invention describes a method of purifying a pesticide that includes: a) melting a pesticide, wherein the pesticide includes at least one active ingredient and at least one impurity capable of inhibiting crystallization; b) coating the pesticide on a substrate to form a pesticide particle; c) substantially reducing the amount of crystallization inhibiting impurity by an azeotropic method; and d) crystallizing the pesticide. In another embodiment, the present invention includes a metho...

A process is provided for removing impurities from a slurry of titanyl hydrate. The titanyl hydrate is separated from the slurry, washed, and reslurried with water to make the resulting titanyl hydrate slurry fluid. The reslurried titanyl hydrate slurry is then treated by the addition of a trivalent titanium compound in an amount between about 0.01 grams and about 0.7 grams trivalent titanium compound measured as TiO.sub.2 per 100 grams titanyl hydrate as calcined TiO.sub.2 in the absence of add...