Mitsubishi Chemical Corporation

Yoshiro Suzuki

Shuhei Yada

Yasushi Ogawa

Kenji Takasaki

Kimikatsu Jinno

Hirochika Hosaka

Masayasu Goriki

Kiyoshi Takahashi

Yasuyuki Sakakura

Norioki Mine

Masahiko Yamagishi

Chikara Sugimoto

Yasuhiko Samura

Mitsuo Nakamura

Yukihiro Hasegawa

Teruo Saito

Shuhei c/o Mitsubishi Chemical Corporation Yada

Yasushi c/o Mitsubishi Chemical Corporation Ogawa

Yasuyuki c/o Mitsubishi Chemical Sakakura

Hirochika c/o Mitsubishi Chemical Corp Hosaka

The present invention provides a method for efficiently using an aqueous solution of (meth)acrylic acid at a low concentration formed in a production/storage step of (meth)acrylic acid. In the present invention, a (meth)acrylic acid derivative is produced by using as a raw material an aqueous solution of (meth)acrylic acid formed by one or both of: a device which reduces a pressure of a gas comprising (meth)acrylic acid in production of (meth)acrylic acid; and a device which collects (meth)acrylic acid from a gas comprising (meth)acrylic acid.

Method for producing (meth) acrylic acid derivitive

A condenser includes: a top face of a tube plate on which acrylic acid may be condensed inside the condenser; a spray for spreading a polymerization inhibitor on the tube plate; a first polymerization inhibitor supply tube for supplying the polymerization inhibitor to the spray; and a supporter for supporting the spray at a predetermined position. The supporter supports the first polymerization inhibitor supply tube outside the condenser. The condenser allows a stable continuous operation for a long period of time by preventing polymerization of an easily polymerizable compound in the condenser into which a vapor of an easily polymerizable compound is supplied with a simple structure thereof.

Handling device and producing system of easy-to-polymerize compound

A method of storing (meth)acrylate in a tank of a less expensive and highly versatile material without losing stability of the stored (meth)acrylate. To be specific, a method of storing (meth)acrylate in a tank, including supplying an appropriate gas for storing (meth)acrylate into the tank, in which: the tank is made of a carbon steel material; the gas has a water concentration of 100 ppm or less; and the (meth)acrylate has a (meth)acrylic acid concentration of 30 ppm or less.

Method of storing (meth)acrylic ester

(Meth)acrolein or (meth)acrylic acid is collected by bringing a reaction gas () containing (meth)acrolein or (meth)acrylic acid obtained through a vapor-phase catalytic oxidation reaction into contact with an aqueous solution as a collecting solvent in a collecting tower main body (). The reaction gas () is supplied to the collecting tower main body () from two nozzles () facing each other, and is caused to collide in the collecting tower main body (). According to the present invention, (meth)acrolein or (meth)acrylic acid can be efficiently collected from a gas containing (meth)acrolein or (meth)acrylic acid while preventing polymerization.

Method for collecting (meth)acrolein or (meth)acrylic acid and collecting device for the same

An object of the present invention is to provide a method for vapor phase catalytic oxidation which is almost free of variations in reaction states in respective reaction tubes of the fixed bed multi-tube heat-exchanger type reactor. Provided is a method for vapor phase catalytic oxidation for obtaining a reaction product gas by using a fixed bed multi-tube heat-exchanger type reactor provided with a plurality of reaction tubes and by feeding a raw material gas inside the reaction tubes packed with a catalyst, wherein the method comprises: adjusting pressure losses of the respective reaction tubes so that the pressure losses of the respective reaction tubes after catalyst packing is within &#xb1;20% of an average pressure loss of the reaction tubes by: packing an inert substance at a raw material gas inlet portion of the reaction tubes or removing and re-packing the catalyst packed, for a reaction tube having a pressure loss lower than the average pressure loss of the reaction tubes; and removing and re-packing the catalyst packed, for a reaction tube having a pressure loss higher than the average pressure loss of the reaction tubes.

Method for vapor phase catalytic oxidation

A producing method of (meth)acrolein or (meth)acrylic acid where by use of a multi-tubular reactor that has a plurality of reaction tubes filled with a catalyst, catalytic gas phase oxidation of propylene, propane, isobutylene or (meth)acrolein is carried out in the presence of a composite oxide catalyst by use of molecular oxygen or a gas containing molecular oxygen, in which method (meth)acrolein or (meth)acrylic acid can be obtained stably in high yield for a long period of time without allowing the activity of the catalyst to decrease locally (disproportionately) and extremely. A temperature difference between a temperature of a heat medium at the beginning of operation and a peak temperature of the catalyst is set in a range of 20 to 80&#xb0; C., and during operations a change of the peak temperature T of the catalyst in a tube axis direction is maintained in a definite range.

Process for producing (meth)acrylic acid or (meth)acrolein

The object of this invention is to provide a method of maintaining a multi-tubular reactor which can ensure the uniformity of states of reaction in the reaction tubes in the multi-tubular reactor. This invention is a method of maintaining a multi-tubular reactor in good condition by selecting a part of reaction tubes in a multi-tubular reactor at random, measuring a differential pressure occurring in each reaction tube when passing gas therethrough, separating any reaction tube showing an abnormal differential pressure as compared with the average of differential pressures in reaction tubes packed with an fresh catalyst of the same kind, giving adequate treatment to the separated reaction tube and returning it into the reactor with any other selected reaction tube falling within a normal range.

Method of maintaining a multitubular reactor

An object of the invention is to provide a production method for (meth)acrolein or (meth)acrylic acid which can continue an operation without causing a decomposition reaction of acrolein or the like. According to the invention, provided is a production method for (meth)acrolein or (meth)acrylic acid, in which (meth)acrolein or (meth) acrylic acid is obtained by performing a catalytic gas phase oxidation on propylene, propane or isobutylene by using oxygen by means of a heat-exchange type multi-tubular reactor, having a tube bundle portion in which a multiple of reaction tubes each filled with a catalyst are aligned in parallel to one another and a tube plate which is adjacent to a downstream side of the tube bundle portion of the reaction tubes and forms a lead-out portion for a reaction gas, in which the tube bundle portion of the reaction tubes has a hollow-columnar constitution as a whole, and which is characterized in that a rectifier is provided on a tube plate.

Process for producing (meth)acrolein or (meth)acrylic acid

A decomposition reaction apparatus or distillation apparatus for acrylic acid in which a column bottom liquid heated in a reboiler () is supplied from a supply port () provided on a side wall of a column body () having: a top plate () above the supply port (); and an impingement plate () provided vertically to the top plate (), for preventing scattering of the column bottom liquid to a supply direction. The top plate () is provided such that the top face of the top plate () is inclined downward from a base end to a tip end. The present invention allows: suppression of formation of a polymerized product due to flowing of a liquid or gas heated in a reboiler into a column with a simple structure; and a stable continuous operation of column equipment over a long period of time.

Vessel for easily polymerizable compound

A distillation apparatus for subjecting a crude readily polymerizable compound to distillation under vacuum conditions to purify it, the distillation apparatus having a distillation column and a vacuum generator and an exhaust gas conduit of the vacuum generator connected to a connecting conduit therebetween through a pressure control valve. A method provides purifying of a readily polymerizable compound by subjecting a crude readily polymerizable compound to distillation under vacuum conditions to purify it, the method including using a distillation apparatus having a distillation column and a vacuum generator and an exhaust gas conduit of the vacuum generator connected to a connecting conduit therebetween through a pressure control valve and controlling the action of the pressure control valve based on a pressure of the distillation column.

Distillation apparatus for readily polymerizable compound

A method for purifying a crude (meth)acrylic acid obtained by a vapor phase catalytic oxidation method, characterized in that the crude (meth)acrylic acid having most parts of water and acetic acid removed therefrom, is fed to and distilled in a first distillation column of a purification system comprising first to third three distillation columns, the top fraction from the first distillation column is fed to and distilled in the second distillation column, the resulting top fraction is recovered as a high purity (meth)acrylic acid product, the bottoms from the first and second distillation columns are fed to and distilled in the third distillation column, and the resulting top fraction is fed to the first distillation column.

Method for purifying (meth)acrylic acid

In the stopping and starting operations of a distillation column used for producing (meth)acrylic acids according to the present invention, upon stopping the operation of the distillation column, the heating of a reboiler attached thereto is interrupted and then the reboiler is rapidly cooled; and/or upon starting the operation of the distillation column for production of the (meth)acrylic acids, an inner wall surface of the distillation column is heated to a temperature higher than a condensation temperature of the (meth)acrylic acids and the operation of the distillation column is started under the heated condition. According to the present invention, it is possible to early and safely stop the operation of the distillation column while preventing the occurrence of polymerization within the distillation column, and stably perform an operation for distillation of acrylic monomers for a long period of time.

Process for producing (meth)acrylic acids and process for distilling the same

An oxidation reactor includes a reactor body, a manhole nozzle projecting from the reactor body, and a partition plate separating an inside of the manhole nozzle and an inside of the reactor body from each other. In an oxidation reactor including the reactor body and a nozzle projecting from the reactor body, there is provided a means for feeding an inert gas into the nozzle. In a process for producing (meth)acrylic acids by subjecting propane, propylene or isobutylene to catalytic gas-phase oxidation reaction in an oxidation reactor for producing (meth)acrolein or (meth)acrylic acid, the above oxidation reactor is used as the oxidation reactor. In a method for analyzing an easily-polymerizable compound by introducing a gas containing the easily-polymerizable compound into an analyzing apparatus through a sampling tube, a double tube is used as the sampling tube, and a heating medium is fed into an outer tube of the double tube. According to these methods, the oxidation reaction can be stably conducted, and the reaction product gas can be prevented from being condensed and polymerized in the sampling tube, so that an on-line analysis can be performed at a high accuracy for a long period of time.

Oxidation reactor, process for producing (meth)acrylic acids, and method for analyzing easily-polymerizable compounds

A method for producing (meth)acrylic acid or (meth)acrolein, comprising a catalytic gas phase oxidation process for producing (meth)acrylic acid or (meth)acrolein by supplying propylene, propane, or isobutylene and a gas containing molecular oxygen to a reactor which contains a catalyst filled therein, wherein a gas containing molecular oxygen is supplied to the reactor having the catalyst filled therein during shutdown of the catalytic gas phase oxidation process does not lower the reaction activity of the catalyst and the selectivity of target products when re-starting the running after shutdown of the catalytic gas phase oxidation process.

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Yokkaichi, Japan

Yoshiro Suzuki