Mitsui Toatsu Chemicals, Incorporated

Shinji Takenaka

Hiroyuki Itoh

Masanobu Ajioka

Yoshitsugu Kono

Masafumi Kataita

Ryu Oi

Isao Kikuchi

Chitoshi Shimakawa

Yukihiro Yoshikawa

Kousuke Yamamoto

Yoshitsugu Kohno

Kunihiro Yamada

Kazuo Maeda

Teruo Hirayama

Mitsuo Kudoh

Tooru Hihara

Takeshi Nishida

Kazunori Kawahara

Jun Kitagawa

Michio Mituta

Joshiro Kanemoto

Concentration process of gaseous chlorine

A gaseous mixture containing chlorine, carbon dioxide and non-condensable gas is compressed and cooled to separate it into a residual gas formed principally of a major portion of the non-condensable gas and a condensate formed primarily of chlorine. The condensate is fed to a stripping column to desorb carbon dioxide and a minor portion of the non-condensable gas dissolved in the condensate. The stripped gas formed primarily of chlorine and carbon dioxide may be treated further. Namely, the stripped gas is mixed with the residual gas. At least a portion of the mixed gas is fed into an absorption column, whereby a major portion of remaining chlorine is absorbed to lower the chlorine content Removal of chlorine from such a gaseous mixture or an off-gas from the above process can be achieved by washing it with an aqueous solution or suspension containing an alkali metal sulfite and/or an alkaline earth metal sulfite while controlling the pH of the solution or suspension within a range of 1.9-6.3.

Industrial process for the separation and recovery of chlorine

Disclosed herein is a method for the stabilizing treatment of a catalyst comprising washing the catalyst with hot washing water following the preparation of the catalyst, the catalyst being composed principally of chromium oxide and used in the production of chlorine by the oxidation of hydrogen chloride with an oxygen-containing gas, thereby improving its catalytic activity and prolonging its life.

Method for stabilizing treatment of catalytic activity

Chlorine is produced by reacting hydrogen chloride and oxygen in the presence of a catalyst composed of a chromium oxide as a principal component. The reaction is carried out in a fluidized bed reactor equipped at vertical intervals not greater than 100 cm with a plurality of perforated horizontal plates having a perforation rate of 10-60% in a reaction zone in which the catalyst is fluidized in operation. The reaction zone is above a gas diffuser plate.

Production process of chlorine

Chlorine is produced by reacting hydrogen chloride and oxygen in the presence of a chromium oxide catalyst in a reactor whose catalyst-contacting part is lined with one of lining materials represented by the following general formula (I):

Reactor for the production of chlorine

Disclosed herein is a process for the electroreduction of aromatic acids comprising reducing an aromatic carboxylic acid electrolytically in an aqueous acidic solution by the use of a material of a low oxygen overvoltage as the anode for oxygen generation, thereby producing the corresponding benzyl alcohol in high yield in a single electrolytic apparatus.

Process for the electroreduction of aromatic carboxylic acids

The catalytic activity of a chromium oxide-based catalyst used in the production of chlorine by oxidation of hydrogen chloride gas with an oxygen-containing gas is regenerated by impregnating it with an aqueous solution of chromic acid anhydride or of a chromium salt and then calcining the catalyst at a temperature not higher than 800.degree. C.

Chromium oxide catalyst impregnation regeneration method

A process for producing m-phenoxybenzyl alcohol by reacting chlorobenzene with m-hydroxybenzyl alcohol in the presence of a copper catalyst and a base, the process being characterized by using an alkylene glycol as a reaction solvent.

Process for producing m-phenoxybenzyl alcohol

Chlorine is produced by reacting hydrogen chloride and oxygen in the presence of a chromium oxide catalyst in a reactor whose catalyst-contacting part is lined with one of lining materials represented by the following general formula(I):

A gaseous mixture containing chlorine, carbon dioxide and non-condensable gas is compressed and cooled to separate it into a residual gas formed principally of a major portion of the non-condensable gas and a condensate formed primarily of chlorine. The condensate is fed to a stripping column to desorb carbon dioxide and a minor portion of the non-condensable gas dissolved in the condensate. The stripped gas formed primarily of chlorine and carbon dioxide may be treated further. Namely, the stripped gas is mixed with the residual gas. At least a portion of the mixed gas is fed into an absorption column, whereby a major portion of remaining chlorine is absorbed to lower the chlorine content. Removal of chlorine from such a gaseous mixture or an off-gas from the above process can be achieved by washing it with an aqueous solution or suspension containing an alkali metal sulfite and/or an alkaline earth metal sulfite while controlling the pH of the solution or suspension within a range of 1.9-6.3.

An improved process is provided for the production of chlorine. In a fluidized-bed reactor having a specific equivalent diameter and made of a material with a particular iron content, hydrogen chloride and oxygen are reacted in particular gas volumes and at specific molar ratio, superficial velocity, temperature and pressure in the presence of a catalyst composed principally of a chromium oxide and having a specific particle size distribution. The catalyst is filled in a specific amount in terms of catalyst layer height at rest. The catalyst can retain its high activity.

Chlorine is produced by oxidizing byproduced hydrogen chloride. An offgas containing hydrogen chloride as a byproduct is reacted with oxygen at 300.degree.-500.degree. C. in the presence of a catalyst which contains chromic oxide (Cr.sub.2 O.sub.3) as a principal component. The resulting gas is cooled rapidly and then washed with water to recover vaporized chromium. The hydrogen chloride is then absorbed in water to recover it as an aqueous hydrochloric acid solution. The still remaining portion of the resultant gas is washed with sulfuric acid to remove water from the same, followed by compression and cooling. The resulting liquefied chlorine is separated. The still remaining gas composed principally of oxygen is thereafter returned to the oxidation step.

A process for producing m-phenoxybenzyl alcohol which comprises reacting chlorobenzene with m-hydroxybenzyl alcohol in the presence of a copper compound as a catalyst and a base, characterized in that chlorobenzene is added to a polar solvent having a higher boiling point than chlorobenzene, the amount of chlorobenzene being 0.05 to 4.0 times the weight of the polar solvent; at least one compound selected from alkali hydroxides, alkali carbonates and alkali bicarbonates is used as the base in an amount of 1.0 to 2.0 gram-equivalents per mole of m-hydroxybenzyl alcohol; and the reaction is carried out at a temperature of 140.degree. to 200.degree. C. while removing the generated water as an azeotrope with chlorobenzene.

Process for production of m-phenoxybenzyl alcohol

A process for producing m-hydroxybenzyl alcohol which comprises electrolytically reducing m-hydroxybenzoic acid in an acidic aqueous solution at a temperature of 20.degree. to 70.degree. while m-hydroxybenzyl alcohol is present always in the electrolytic solution. The constant presence of m-hydroxybenzyl alcohol is effected by (1) continuously adding m-hydroxybenzoic acid to the electrolytic solution in an amount corresponding to that consumed as the electrolytic reaction proceeds, or (2) by continuously adding m-hydroxybenzoic acid and the acidic aqueous solution to the electrolytic solution.

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Omuta, Japan

Shinji Takenaka