Abstract: A simulated moving bed connected with a sample supply apparatus is constructed such that a sample liquid can be supplied continually to a simulated moving bed separation device without causing any problems due to a penetration of gas phase and admixture of the plurality of sample liquids. At this end, the sample supply apparatus is composed of a plurality of sample supply vessels each with a sample liquid passageway disposed thereto, a sample liquid-amount management vessel for storing a sample to be supplied from the sample supply vessels through the sample liquid passageways and the supplying sample liquid through the liquid-amount management vessel to the simulated moving bed chromatographic device. The apparatus also has a control for alternatingly opening and closing opening-closing devices in the sample supply vessels in response to liquid levels in the sample liquid-amount management vessel.

Abstract: This invention provides a concentrator capable of drawing out a concentrate of a constant concentration. The concentrator includes a heater having a heating medium that has been heated to a temperature not less than the boiling point of a solution fed to the concentrator—whereby said heater heats the solution to evaporate the solvent to a vapor to make a mixture of the vapor and a liquid—and a gas-liquid separator for dividing the mixture into the liquid and the vapor. The concentrator provides for returning the liquid separated in the gas-liquid separator to the heater, for drawing out a portion of the liquid separated in the gas-liquid separator, for detecting the concentration of an intended component in the drawn out liquid, and for controlling the liquid draw-out so that when the concentration is above a predetermined threshold, liquid draw-out commences, and when the concentration is below the threshold, liquid draw-out stops.

Abstract: This invention provides a concentrator capable of drawing out a concentrate of a constant concentration.

Abstract: The sample supply apparatus for a simulated moving bed chromatographic device is constructed such that a sample liquid can be supplied continually to a simulated moving bed separation device without causing any problems due to a penetration of gas phase and admixture of the plurality of the sample liquids.

Abstract: The present invention relates to a process for producing a highly purified acetic acid characterized in that in the process for producing acetic acid comprising the step of continuously reacting methanol and/or an aqueous solution of methyl acetate with carbon monoxide in a reactor, a treatment is conducted to limit the concentration of unsaturated compounds in crude acetic acid obtained in the process to 5 ppm or lower, and the resultant crude acetic acid is ozonized. The present invention also relates to a process for producing a highly purified acetic acid, characterized by comprising the step of continuously reacting methanol and/or an aqueous solution of methyl acetate with carbon monoxide in a reactor while maintaining the concentration of acetaldehyde in a reaction fluid in the reactor at 1500 ppm or lower.

Abstract: A process for continuously producing acetic anhydride alone or acetic anhydride and acetic acid by reacting methyl acetate and/or dimethyl ether and, optionally, water and/or methanol, with carbon monoxide alone or carbon monoxide and hydrogen in the presence of a rhodium compound and methyl iodide as principal catalysts. Trace impurities causative of tar formation are distilled and separated in an evaporator and/or a subsequent refining step to remove the same. The removal of the trace impurities causative of tar formation serves to decrease the amount of tar formed as an impurity.

Abstract: Acetic acid and/or acetic anhydride containing methyl crotonate, vinyl acetate, or both as impurities, is contacted with ozone in an amount of excess molar to the carbon-carbon double bond in said methyl crotonate and/or vinyl acetate and the impurities produced by ozone-treatment are removed off by distillation. A large quantity of impurities such as aldehydes are produced after treatment by treating acetic acid and/or acetic anhydride containing much amount of unsaturated compounds as impurities with ozone. Distilling the ozone-treated acetic acid and/or acetic anhydride make it possible to remove methyl crotonate and vinyl acetate, which are unsaturated compounds difficult to remove by the conventional separation methods, to give high-quality acetic acid and/or acetic anhydride excellent in the residence time in the potassium permanganate test.