Daicel Chemical Industries, Ltd.

Kuraray Co., Ltd.

Tanabe Seiyaku Company, Limited

Masahiro Kagotani

Hidetaka Kojima

Takashi Sato

Masahiko Shimizu

Hiroyuki Miura

Yasuteru Kajikawa

Yasuo Tsuji

Tadashi Sato

Taizo Watanabe

Yoshiaki Morimoto

Zenjiro Honda

Shinji Nagamatsu

Satoshi Minobe

Takeshi Horikawa

Takashi Nishimura

Tomonobu Ase

Stephen Hanessian

By employing a process for the preparation of acetic acid which comprises carbonylating methanol with carbon monoxide in a first reactor in the presence of a reaction fluid comprising a rhodium catalyst, methyl iodide, an iodide salt, methyl acetate and water, while continuously withdrawing the reaction fluid from the first reactor and introducing it into a flash zone to separate it into an evaporated part and an unevaporated part, characterized in that second reactor is provided between the first reactor and the flash zone and methanol is carbonylated with the carbon monoxide contained in the reaction fluid in a state in which it is dissolved therein in the second reactor with a residence time of 7 to 60 seconds at 150.degree. to 220.degree. C., the carbon monoxide contained in the reaction fluid withdrawn from the first reactor in a state in which it is dissolved therein can be converted into acetic acid in the second reactor through the same carbonylation as that occurring in the first reactor, which enables effective use and high recovery of carbon monoxide.

Process for the preparation of acetic acid

A process by which iodine compounds contained in crude acetic anhydride or a mixture of crude acetic anhydride and crude acetic acid can be converted into methyl iodide having a low boiling point and which can be separated by distillation and efficiently removed by the combination of the conversion step with the heat treatment step and distillation step. The process includes the steps of heat-treating the crude acetic anhydride or the mixture of crude acetic anhydride and crude acetic acid in the presence of methanol and/or methyl acetate in a treatment tank and distilling the heat-treated crude acetic anhydride or the heat-treated mixture of crude acetic anhydride and crude acetic acid, in the presence of an alkali metal salt and/or an alkaline earth metal salt if necessary.

Method of removing iodine compounds from crude acetic anhydride

A high purity acetic acid is prepared by reacting methanol with carbon monoxide in the presence of a rhodium catalyst, iodide salts, and methyl iodide, wherein an acetaldehyde concentration in the reaction liquid is maintained at 400 ppm or lower. This may be attained by contacting the liquid containing carbonyl impurities with water to separate and remove the carbonyl impurities. After that, the liquid can be returned to the reactor.

Process for producing high purity acetic acid

A process for producing porous, spherical particles of cellulose fatty acid esters which comprises dissolving a cellulose fatty acid ester and a gelling agent therefor in an organic solvent, adding the solution thus obtained to an aqueous medium with stirring to form droplets, converting said droplets to gel particles of cellulose fatty acid ester in the presence or absence of a gelation accelerator, and separating porous, spherical particles of cellulose fatty acid ester.

Process for producing porous, spherical particles

Pyrogens are removed out of a solution thereof by (1) treating the solution with a membrane and then (2) treating the resulting solution with a pyrogen adsorbent. The obtained solution is useful in pharmaceutical fields.

Process for removing pyrogens

A process for selectively deacetylating an acetyl derivative of a saccharide is described, comprising treating an acetyl derivative of a monosaccharide or oligosaccharide using a mixture of an aqueous solution of alkali metal hydroxide/aqueous hydrogen peroxide/organic solvent to selectively hydrolyze acetate bonds at specific positions in the molecule, and thereby obtain a partially hydrolyzed acetyl derivative of a saccharide.

Process for selectively deacetylating acetyl derivatives of saccharides

An O-acetyl compound, such as acetic anhydride, is prepared by carbonylating the corresponding O-methyl compound, such as methyl acetate, by heating the latter at 130.degree. to 250.degree. C. with carbon monoxide of a partial pressure of 1 to 100 kg/cm.sup.2 G in the presence of a rhodium catalyst and a iodine compound, whereby the reaction is caused to take place in a reaction solution containing a carboxylic acid in the presence of an aluminum accelerator and a rhodium catalyst treated with hydrogen.

Preparation of acetyl compounds

In a process for producing an aldehyde by hydroformylating allyl alcohol with carbon monoxide and hydrogen gas in the presence of a catalyst comprising a rhodium compound and a tertiary phosphine in an organic solvent and separating the resulting aldehyde with water extraction from the reaction mixture, the catalyst is maintained and recovered in the activity by treating the catalyst-containing solution in the organic solvent with a gaseous mixture of carbon monoxide and hydrogen gas after the water extraction step.

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Hyogo, Japan

Masahiro Kagotani