USRE12762E - Adolph frank - Google Patents

Description

UNITED STATES OFFICE.

ADOLPH FRANK, OF,CHARLOTTENBURG, AND'NIKODEM CARO, OF BERLIN, GERMANY, ASSIGNORS, BY MESNE ASSIGNMENTS, TO AMERICAN OYANAMID COMPANY, OF PORT- LAND, MAINE, A CORPORATION.

PROCESS OF MAKFNG NITROGEN'DOMPOUNDS.

No. 12,762. M

Original No. 785,161, dated March 21, 1905,

To all whom it may concern:

Be it known that-we, AD

' act description of the invention, such as will of August 10, 1895, and in our patent of the enable others skilled in the art to which it 10 apXertains to make and use the same;

trogenunder certain conditions-for Lin-- stance, in the presence ofaqueous vapor, as-

described in our British Patent N 0. 15,066,

United States, No. 590,217- of September 21, 1897, or in the presence of an oxid of a metal as described 1n our patent of the United States, No. 623,709, of April 25, 1899and that cyanids correspondlng to the carbid used are obtained from the products of the reaction;

- "Although the yield of the ,cyanid by the processes described is highly satisfactory, B-U yet, it appeared to us to be inadequate, and

this led 11's to further investigation, which resulted in the discovery of the cause of it, which we found to be due to a great ortion of the nitrogen being fixed in the orm of 1 other nitrogen compounds-namely, in the form of cyanamids, also called amidocyanid and amidooxyc anid in the case of calcium carbid accor ing to the following equation: I

etc N,'=caNcN c described in our patents above re erred to .1

was due chiefly to the more or less complete melting of the carbid or the carbid-formingi.

mixture during the reaction and that this also has a disadvantage in that it prevents the'absorptionof nitrogen to a cat extent, while ,substantially complete a sorption or saturation takes place when the carbid re- OLPH FRANK, of- Oharlottenburg, and NIKODEM OARO, of Berlln, Germany, have invented certain new and Specification of Reissued Letters Patent. Reissued Mar. 10, 1908.

Serial No. 699,847. Application for reissue filed June 25, 1907. Serial No. 380,989.

mains unmeltedthat is to say, in a pulver ulent or porous state. v

' As is well known, the carbids of the alkalies, such as sodium and potassium carbid, melt at the temperatures towhich they must be heatednamely, to from a dark-red to a bri ht-yellow heatin order to readily absor nitro en, while the melting-point of other carbids, as for instance, barium carbid is so close to that temperature that melting can hardly be prevented, especially when compounds of the carbid-containing. substances which melt at thoseftemperatures or at a lower temperature are emplloyed such substances acting as a flux. T s, however,

is not the case with calcium and some other carbids the melting-point of which is much higher than the temperatures to Which-they are to beheated for'the ready absorptionjtof These investigations and expei- 1' ments led "us to the discovery of dividing the process into. two separate steps, consisting in nitrogen.

rst reacting-with nitrogen upon certain carbids or jcarbld-forming mixtures heated to a temperature below their melting-point, but

' sufficiently high to readily absorb nitrogen, whereby the cyanamids above referred to are chiefly formed, and then melting the reaction,

prgduct to convert the cyanamids into cya-g n1 j In carrying out our invention pure-nitrogen or nitrogencompou-nds, as ammonia,

may be used, and we proceed as follows: The calcium carbid, for'instance, is heated in a suitable furnace to a temperature below the melting-point, preferably not higher than to 7 a dark-red or bright-yellow heat, or to. a tem- 9'0 perature which may vary from about900 to 1,000 centigrade, and isthen reacted on with nitrogen until absorption "of the latter ceases. As the carbid is not melted, there is no interference with the absorption'of'nitro- T gen, which thus proceeds much more rapidly and completely, while cyanamid is chiefly 7 formed, which in the older rocesses was lost I to a great extent and whic may be extracted as-hereinafter described. To convert this cyanamidin'to cyanid, the roduct of the reaction is remb ed from the mace and melted, which isi'rriaterially facilitated and expedited by the-addition thereto before or during melting; of a, suitable flux-for instance, caustic soda, caustic potash, sodium carbonate, potassium carbonate, or other suitable salts. As a certain proportion of carbon is set free during the action of the nitrogen on the carbid and should the product of the reaction be deficient in carbon, it is advantageous to make up the deficiency by the addition of a quantity of carbon; On the other hand, the product of the reaction should conextracted in the usual manner.

. tended to cover any form of such.

tain sufficient of the base to bind the cyanogen formed by the melting of the said product, andif this should not be the case a basic substancefor instance, an 'oxy en compound of the alkalies or of the alkaline earths such as caustic soda, caustic potash, sodium, or potassium carbonate, lime, calcium carbonate, or the likeis also added,w hich may of course also be usedas fluxes, as above stated. 1 I

By the meltin of the reaction product the metal compoun for instance, of the calcium cyanid formed-namely, the cyanamid CaNCN-is converted into cyanid according to the equation CaNCN+C= (la(CN) and is Cyanamid may, however, be obtained by leaching it out of the reaction product with Water and extracting it from the solution by means of a suitable solvent, as ether, from which it may be obtained by evaporation.

Any carbid that will not melt when heated to from a dark-red toazbright-yellow heat can therefore be employed in our process, and it is of course immaterial in what form the carbid 'is used, whether as such-'i,. 6., pure carbid or carbid in'the process of formation or in the form of its reaction components. The term carbid is therefore in- We claim: 1. The process of producing cyanid fro carbids, which consists incheating from a dark-red to a bright-yellow 'heat, a carbid that will not melt at these temperatures, re-

acting upon the heated carbid with nitrogen, y

2. -The process, whichconsists in heating to from a dark-red to a bright-yellow heat a carbid that will not melt at these temperatures, reacting ,upon the heated carbid with nitrogen, then melting the reaction product in the presence of carbon and extractin the cyanid in the usual manner, substantial y as set forth.

3. The process, which consists in heating to from a dark-red to a bright-yellow heat a carbid that will not .meltat these temperatures, reacting upon the heated carbid with nitrogen, melting the reaction product in the presence of an oxygen compound of an alkali metal and extracting the cyanid in the usual manner, substantially as set forth.

4. The process, which consists in heating to from a dark-red to a bright-yellow heat a carbid that will not melt at these temperatures, reacting upon the heated carbid with nitrogen, and leaching the cyanamid out of the reaction product.

5'. The process of producing calcium cyanamid which consists in reacting with nitrogen upon calcium carbid at a temperature suflicient to produce calcium cyanamid but below that required for converting calcium ADOLPH FRANK. NIKODEM GARO.

Witnesses HENRY HASPER, WOLDEMAR' HAUPT.