Produits Chimiques Ugine Kuhlmann

Atochem

Jean Combroux

Serge Y Delavarenne

Jean P Schirmann

Jean-Pierre Schirmann

A continuous method for the preparation of concentrated aqueous solutions of hydrazine hydrate from ketazines which are slightly soluble in water, by hydrolysis and distillation under pressure using a distillation column. The column is fed with the ketazine or ketazines and water wherein the water/azine molar ratio ranges between 5 and 7.75.

Process for the preparation of concentrated solutions of hydrazine

A continuous method for the preparation of concentrated aqueous solutions of hydrazine hydrate from concentrated aqueous solutions of acetone azine by a hydrolysis reaction and distillation under pressure in a column. The concentration of the aqueous solution of acetone azine is such that the water/azine molar ratio ranges between 3 and 7.

Preparation of concentrated aqueous solution of hydrazine hydrate

A process for the production of chlorine dioxide by the reaction of an alkali metal chlorate and hydrochloric acid in aqueous solution at temperatures of from about 35.degree. to about 70.degree. C. wherein the chlorate and the hydrochloric acid are introduced into a first reaction zone (the primary reactor) and after a residence time of two to ten minutes the reactants are fed through a system of reaction zones (secondary reactors) filled and emptied in sequence, the temperature of the reaction mixture in each secondary reactor being equal to or at most 15.degree. C. above that in the primary reactor, the residence time in each secondary reactor being from 20 to 40 minutes, the process permitting the use of less expensive reactor materials, such as polyvinyl chloride, with consequent savings in the cost of the reactors so employed.

Plural zone process for the preparation of chlorine dioxide

A process is described for the production of azines by contacting in the liquid phase ammonia, hydrogen peroxide and a carbonyl compound, either an aldehyde or a ketone. The reaction takes place in the presence of an amide (I) of a monocarboxylic or dicarboxylic acid, wherein at least one of the ionization constants is below 5 .times. 10.sup.-5, and further in the presence of an inorganic or organic catalyst (II), having the atomic structure H--X--Y.dbd.Z, H representing hydrogen, X and Z representing oxygen or nitrogen and Y representing carbon, nitrogen, phosphorus, arsenic, antimony, sulphur, selenium or tellurium. It is possible for X, Y or Z to carry other substituents, providing valency rules are obeyed. The process is carried out in the presence of the ammonium salt (III) of the carboxylic acid corresponding to the amide (I), at the rate of at least 0.1 mole of the ammonium salt (III) per mole of hydrogen peroxide employed.

Process for making azines

Ammonia and aldehydes or ketones are selectively oxidized by hydrogen peroxide to the corresponding azines when they are reacted in the presence of both (a) an amide of a carboxylic acid having a pK greater than about 4.3 and (b) a co-catalyst having the general formula H--X--Y=Z, wherein H is hydrogen, X and Z are each an atom of oxygen or nitrogen and Y is an atom of carbon, nitrogen, arsenic, antimony, phosphorus, sulfur, selenium or tellurium; the atoms of X, Y, and Z carrying other substituents necessary to obey the rules of valence. Preferred co-catalysts include di(alkali metal) hydrogen phosphates, lower dialkyl phosphate esters, bicarbonates and p-toluene sulfonic acid. When 1.degree. or 2.degree. amines are also present, hydrazones are also formed along with the azines. Uses of the resultant products include their hydrolysis to hydrazines with recycling of aldehyde or ketone.

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Mornant, France

Jean Combroux