US1059809A

US1059809A - Manufacture of persulfates.

Info

Publication number: US1059809A
Application number: US58557110A
Authority: US
Inventors: Gustav Adolph; Albert Pietzsch
Original assignee: Individual
Current assignee: Individual
Priority date: 1910-10-06
Filing date: 1910-10-06
Publication date: 1913-04-22
Anticipated expiration: 1930-04-22

Description

"siding at Munich,

TEN FTEL GUSTAV ADOLPH AND ALBERT,PIETZSCH, OF MUNICH, GERMANY.

MANUFACTURE OF PERSULFATES.

No Drawing.

'same is based on the utilization of persulfate of ammonium, such'as can be readily obtained by electrolytic methods, for this purpose. In this art, the production of potassium-persulfate is at present carried out either by directly preparing the same electrolytically, or by the. conversion of ammonium-persulfate. The latter method has the advantage that. it takes as a starting product ammonium-persulfate which is readily obtainable by electrolytic methods,

while the potassium-persulfate" can only be obtained with difficulty and-with very poor yields. of starting with ammonium-persulfate, however, resides in the fact that the ammoniumpersulfate isflreacted on by potassium-carbonate, a very costly reagent, and that thereafter the ammonium-sulfate mustbe regener ated from the ammonium carbonate by the aid of sulfuric-acid.

V The object of the present invention is to overcome the difficulty above pointed out, and

with this object in view, the applicants have devised the present invention which is based on the discovery made by them, that potassium-persulfate may be direct-1y obtained from the sulfates of.potassium, under which term are to be understood not only the neu-' tral sulfatesbut other sulfates, such as bisulfateof potassium, said reaction proceeding according tothe equatlons z thisimanner the ammonium persulfate Specification ofLetters Patent.

A disadvantage of the said method Leda-( essa Patented Apr. 22, 1913.

Application filed October 6, 1910. Serial N 0. 585,571.

may be readily and simply converted into persulfate of potassium, a sulfate-of-ammonium solution being obtained as one of the byproducts of the reaction, from which an ammonium-persulfate solution may be readily obtained electrolyticallydirectly or with the addition of sulfuric-acid. From this it will be seen that the manufacturer has it in his power to regenerate the ammonium-persulfate continuously during the process and as the same is required.

Under the present invention potassium persulfate is directly obtained from potassium sulfate with as advantageous a utilization of the electric current as in the case Where ammonium persulfate is obtained fromammonium sulfate. This new process is based on the fact that, as applicants have found, solutions of ammonium persulfate which has been obtained by known electrolytic methods, may be directly acted on by sulfate of potassium in solid formiand undissolved, in such a way that an ammonium sulfate remains in the solution.

The following example is given for the purpose of fully disclosing the invention:

Example 1: To an ammonium-persulfate,

solution obtained. electrolytically, there is added an equivalent amount of'potassiumsulfate or of potassium-bisulfate in a powdered or solid form, the mixture being vigorously agitated and gently heated. The potassium-persulfate isimmediately separated from the solution in theform of fine crystalline laminae orplates, and may be separated by the usual methods, such as siphon- .ing ofi' liquid, by decanting,

tion, or otherwise. The remaining solution of ammonium-sulfate, either in the neutralform or as bisulfate, can then be regenerated to ammonium-persulfate by sub jecting the same to electrolysis.

- The applicants have further found that the conversion of ammonium-persulfate to potassium-persulfate can be carried out to particular advantage when this is done in connection With the electrolytic action in the electrolyzer, for which purpose ,a mixture of ammonium sulfate and potassium sulfate, under which terms are to be understood either .the neutral or bisulfates, is directly centrifugal acutilized. Under these conditions, the ammonium-persulfate is formed at the anode with the usual. good yields, amounting to 80% and upward. This freshly generated ammonium-persulfate is, however, immediately and at the moment of its format-ion converted into potassium-persulfate and ammonium-sulfate by the reaction of the potassium-sulfate existing in the bath or solution. The potassium-persulfate thus formed is thrown out in solid form. and the ammonium-sulfate is then. again converted into the persulfate, under the action of the current. Under this method of proceeding, it is, therefore, only necessary to supply the potassium-salt as fast as it is consumed, by additions of further quantities of potassiumsulfate (neutral or bis'ulfate) in order to obtain a continuous uninterrupted production of potassium-persulfate with high yields. very great advantage in this connection is,

that the process may be carried out without the intervention of a diaphragm, for the reason that practically no persulfate remains in solution. The following example will serve to more fully disclose this modification of the process.

' Example 2: A solution of 200 grams of ammonium-bisulfate together, with 400 grams of potassiunrbisulfate is subjected to electrolysis in the usual manner with the aid of platinum electrodes and without the intervention of a diaphragm, the electrolyte remaining constantly in contact with solid potassium-bi'sulfate. Under this treatment solid potassium-persulfate is thrown down in the bath while ammonium-bisul-fate goes into solution. This process may be carried .out with a yield of from at the anode, while the reduction does 'notexceed more than 1. to 2%. A surprising discovery made by these applicants in this connection is, that by the same treatment sodium-persulfate, a body which has been'very difficult to obtain heretofore, being very readily soluble, can be obtained with ease. Hitherto this'salt could not even be obtained with the aid of carbonate of sodium fro-m am monium-persulfate; it was necessary for this purpose to employ caustic sodaor sodium-- hydrate, the escaping ammonia under this treatment having been absorbed with sulfuric-acid. The applicants havefound that by using the same -method as above de-' scribed, the ammonium-persulfate may be readily converted into sodium persulfate, leaving asa by-product ammonium-sulfate,

by treating the said ammonium-,persulfate with sodium-sulfate (neutral or bisulfate). Here again, the conversion may be carried out concurrently with the electrolysis with particular advantage. However, in this case, -in viewl of the ready solubility of sodium-persulfate, the two electrodes must be separated by a diaphragm. After the electrolyte has been saturated with sodiumpersulfate, the latter begins to be precipi tated, the sodium-salt thus precipitated being replaced bysodium-bisulfate. In order to more fully disclose this process the following example may .serve p Example 3: A solution of 500grams sodium-bisulfate together with 500 grams amperiod of time, sodium-persulfate begins tov The be precipitated-in the anode space.

-yield under this process attains about 80%.

It will be noted that the term sulfates as employed in the claims includes not only the neutral sulfates but also the bisulfates.

What we claim and desire to secure by Letters Patent is as follows:

1. The. process of obtaining a persulfate of an alkali-metal, which consists in causing a sulfate of said alkali-metal in an undissolved state to react on a bath of ammonium persulfate.

y 2. The process of obtaining a persulfate of an alkali-metal, which consists in mixing ammonium sulfate in abath with a sulfate of an alkali-metal and subjectingthe bath to electrolysis.

3. The process of obtaining a persulfate of an alkali-metal, which consists in sub- 'jecting a bath containing ammonium sulfate and a. sulfate of-said alkali-metal to electrolysis, and adding fresh supplies of alkalimetal sulfate as the conversion of the alkalimetal sulfate into the persulfate proceeds, to reconvert persulfate of ammonium into the sulfate.

4. The process of obtaining a 'persulfate of an alkali-metal, which consists in subjecting' 'a bath containing ammonium. sulfate and, undissolved. alkali-metal sulfate to' electrolysis, and adding fresh supplies of solid alkali-metal sulfate as the electrolysis proceeds, to reconvert persulfate of' ammonium into the sulfate. Q i

5. The process of obtaining potassium:

persulfate, which consists in causing a sulfate of. potassium in an undissolved state to react on a' solutlon of ammoniumrpersulfate.

'6. The process of obtaining potassiumpersulfate. which consists in subjecting a bath containing a potassium-sulfate and ammonium-sulfate to electrolytic action.

7. The process of obtaining persulfate, which consists in su jecting a otassiumbat-h containing potassium-sulfate and amour signature s in the presence of two witmonium sulfate to electrolytic action, and nesses.

adding fresh supplies of potassium sulfate GUSTAV ADOLPH. to the bath as the reaction proceeds to re- ALBERT PIETZSCH.

5 convert persulfa-te of ammonium to the Witnesses:

sulfate.

A. VERE W. fCo'rTER, In testimony whereof we hereunto aflix MATHILDE K. HELD.