DE244816C - - Google Patents

Description

IMPERIAL

PATENT OFFICE.

PATENT LETTERING

- M 244816 - 'CLASS 55 b. GROUP

Bicarbonate are exempt.

Patented in the German Empire on February 10, 1911.

The invention aims to obtain acetic acid and formic acid from waste liquors the soda cellulose production, which was previously made of humus substances and soda in the form of bicarbonate is exempt. The novelty is that such bases are treated with an acid that is stronger than carbonic acid, so z. B. with oxalic acid, hydrochloric acid or phosphoric acid, what to look through

ίο Distillation receives acetic acid and formic acid.

They can of course be traced in the excretion of acetic acid and formic acid Wish received together or individually.

The filtrate can e.g. B. first made partially acidic with the stronger acid, so that the acetic acid is freed and can be distilled off, while the stronger Formic acid remains bound to soda. After the acetic acid has been distilled off, the residue becomes complete acidified to free the formic acid

■ close. The resinous acids present in the lye remain if they are not present or during the distillation of acetic and formic acid by filtration, foaming or otherwise removed, along with water-soluble, syrupy materials together with the sodium salts of the acid or acids used as distillation residue return. If desired, this residue can undergo dry distillation in or be subjected to without the presence of water vapor, with z. B. Lactic acid is formed will and can be won. . The distillation residue can also be used with alcohol or another act in the same way to treat the solvent for the organic substances, until these are dissolved, whereupon they are excreted from the salt mass according to known methods can be. If the alcohol is anhydrous, it can, especially after heating and in the presence of a condensing agent, lactic acid esters are formed and be distilled off as such. As a solvent, you can also use low alcohol instead of alcohol Use lots of water, preferably warm. The residue obtained from inorganic Salting is particularly suitable for the production of new cooking liquor, as it does not contain any annoying impurities.

If the stronger acid used to liberate the organic acids is oxalic acid, it should expediently be added in a water solution, preferably warmer. the The reaction becomes complete if calculated quantities are used. Has the solution has a sufficiently high concentration of strongly dissociated salts, for example table salt, so, even from a warm solution, the sodium oxalate formed in the reaction becomes in Form of a fine crystal powder completely precipitated, so that the solution of vinegar, Formic acid, etc., which is chemically free from oxalic acid, can be separated from oxalate can without losing anything of it.

This oxalate can be washed with water, and the wash water can expediently be used to dissolve new amounts of oxalic acid. Sodium oxalate can be treated with caustic lime to produce caustic soda for cellulose boiling and calcium oxalate to produce new amounts of oxalic acid.
When causticizing the sodium oxalate

ίο one should proceed expediently in such a way that the sodium oxalate crystal mass obtained is introduced immediately with stirring into a little more than the calculated amount of milk of lime at normal room temperature. In this way, a complete conversion of the sodium oxalate into calcium oxalate and sodium hydroxide solution is achieved in a relatively short time if the amount of oxalate per liter of milk of lime does not exceed 70 g Na _{2 O.} The milk of lime for causticizing the sodium oxalate is expediently prepared by slaking lime with the washing water of the calcium oxalate precipitation.

When using hydrochloric acid to free the organic acids can the common salt formed is advantageously decomposed by electrolytic methods, namely especially because the sodium hydroxide solution obtained in this way is used for cellulose cooking can be without hindrance by their salt content. Here is also the advantage achieved that chlorine and hydrogen can be converted into hydrogen chloride which can be used to acidify new amounts of black liquor. Soda can also be made from table salt using the ammonia soda process. This The method is particularly advantageous for the reason that the soda obtained does not need to be freed from table salt, and because you can then also make soda from new amounts of table salt at the same time the loss of soda when cooking cellulose with such cheap saline soda solution to cover completely. Furthermore, the obtained ammoniacal bicarbonate needs bicarbonate not to be calcined but can be in solution of ammonia and Can be de-carbonated, which is much cheaper.

If, on the other hand, sulfuric acid is used to liberate the organic acid, then it can Soda can of course be obtained from the obtained sulphate using the Leblanc method. The soda solution obtained is causticized immediately into cellulose cooking liquor.

If one finally uses phosphoric acid to free the organic acids, then one can one directly from the obtained sodium phosphate with lime caustic soda for cellulose boiling and produce calcium phosphate. The phosphoric acid is then in a known manner from the calcium phosphate means Sulfuric acid regenerates.

Claims (1)

65 patent claim: Process for the production of acetic acid and formic acid from the waste liquors Soda cellulose production, previously made of humus and soda in the form of bicarbonate are exempt, characterized in that these alkalis are treated with an acid that is stronger than carbonic acid is e.g. B. with oxalic acid, hydrochloric acid or phosphoric acid, whereupon acetic acid and formic acid are distilled off. Berlin, printed in DBr reichsdruckerEI.