Asahi Kasei Kogyo Kabushiki Kaisha

Toshiyuki Iwaisako

Junzo Masamoto

Koichi Yoshida

Katsuhiko Hamanaka

Kazuhiko Matsuzaki

Hajime Komaki

Akio Inoue

Yoshinobu Ito

Susumu Isohata

Naomi Yamaguchi

Kazutaka Watabe

Morio Shimoshimizu

Takeshi Naito

Hisao Yomogida

A method for synthesizing trioxane by heating and reacting an aqueous formaldehyde solution in the presence of a heteropolyacid. As the heteropolyacid, there is preferably used one that contains, as a coordinating element or coordinating elements, W, Mo, V or Nb alone or two or more of them.

Method for synthesizing trioxane

A process for recovering trioxane from an aqueous solution containing trioxane and triethylamine by the distillation separation process which comprises feeding an aqueous solution containing trioxane and triethylamine to the first distillation column, distilling out triethylamine, trioxane and water from the column top of the first distillation column, withdrawing an aqueous solution containing the major part of the trioxane present in the fed solution from the column bottom of the first distillation column, feeding the withdrawn solution to the second distillation column and taking out the substantially whole quantity of the trioxane fed to the second distillation column from the column top of the second distillation column.

Process for recovering trioxane by plural distillation

An oxymethylene copolymer produced from trioxane, a cyclic ether and/or a cyclic formal in the presence of a cationic polymerization catalyst is contacted with a deactivating agent for the catalyst in the state of gas phase at a temperature of 160.degree. C. or lower to deactivate the cationic polymerization catalyst rapidly and completely without causing degradation of the copolymer produced.

Process for deactivating polymerization catalyst

Shaped composite adsorbent and a process for preparing the same

In a process for separating trioxane by a continuous distillation which comprises extracting, with benzene, the trioxane-containing distillate obtainable by heating an aqueous solution of formaldehyde, feeding the trioxane-containing benzene solution into a distillation column as a starting material, distilling out the benzene from the column top and withdrawing the trioxane from the column bottom, a process for separating trioxane which comprises retaining the concentration of trioxane X in the liquid composition at the starting material feeding plate of the distillation column (% by weight of trioxane based on the total liquid composition at the feeding plate) in the range satisfying the following relationship: ##EQU1## wherein R is reflux ratio, and .gamma. is a parameter defined by the following equation: ##EQU2## wherein q is the proportion of liquid part in the fed starting material as expressed in terms of ratio by weight and C (%) is the concentration of trioxane in the fed starting material.

Process for separating trioxane

Pseudo-boehmite having a bulk density of about 0.05 to 0.2 g/cc, an oil absorption of about 2.5 to 6.0 cc/g, a pore volume of about 2.0 to 7.0 cc/g over a pore diameter range of 176.mu. to 0.0035.mu. and a specific surface area of about 200 to 500 m.sup.2 /g, and a process for producing the same; useful as a filler, an absorbent, a catalyst, a filtering agent and a base material for composites; prepared by mixing alkali aluminate and halohydrin together at a low temperature, heating for reaction the resulting mixture, cooling the reacting solution, separating the resulting precipitate by filtration and, if desired subjecting the precipitate to washing with an organic solvent followed by drying.

Process for producing pseudo-boehmite

A magnesia cement composition comprising active magnesia, magnesium sulfate, and pulp or a mixture of pulp and fibrous glass. When hardened, this composition yields a crack-free low-shrinkage material. Valuable composite boards are obtained by lamination from the hardened composition and core materials such as cellular concrete, plywood, plastic foam, gypsum plaster board, and cemented excelsior board.

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Fuji, Japan

Toshiyuki Iwaisako