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nitrate or nitrite, provided either of these latter is not heated beyond its decomposing-point.

PROCESS OF MAKING NITRIC ACID.

Heinrich Hugo Niedenführ, of Halensee, Germany. Patent No. 798,205, dated August 29, 1905.

This invention refers to a process for manufacturing nitric acid by means of which it is possible to effect a practically perfect condensation of the nitric-acid vapors and the removal of the lower oxids of nitrogen, the latter being at the same time submitted to a practically complete condensation and oxidation into nitric acid.

This process practically consists in treating nitrates with a suitable acid and generating fumes of oxids of nitrogen substantially without foreign oxidizing agents, treating the concentrated and undiluted fumes evolved to an immediate condensation process out of contact with said nitrates at a comparatively high temperature and at a somewhat-reduced pressure, separating the condensed and liquefied nitric acid from the uncondensed gaseous lower oxids of nitrogen and preventing any substantial absorption of the said oxids by the liquid, then condensing said gaseous lower oxids of nitrogen at a lower temperature and at an increased pressure and in contact with the liquefied portion of said gaseous oxids, keeping said lower oxids under pressure and at a low temperature until practically all of the gas is condensed and collecting the resulting liquefied lower oxids and oxidizing the same.

PROCESS OF MAKING SODIUM FERROCYANID. Camille Petri, of Buchsweiler, Germany. Patent No. 798,208, dated August 29, 1905.

This invention is based on the discovery of the fact that sodium ferrocyanid, which is formed by the addition of sodium chlorids to a solution of calcium ferrocyanid according to the formula Fe(CN) Ca2+ 4NaCl = Fe(CN),Na, +2CaCl2,

admits a ready separation from the simultaneously-produced chlorid of calcium. The sodium ferrocyanid thus formed may be obtained from the solution by crystallization as well as by separation in concentrating the same, while the simultaneously-formed chlorid of calcium remains in solution in view of its being considerably more soluble at any temperature, so that it may be easily separated from the sodium ferrocyanid. It may be stated that the above effect is obtained without the use of sodium carbonate in conjunction with sodium chlorid. The production and the separation of the sodium ferrocyanid takes place very easily from that reason also, because it has been ascertained that there is no subsequent decomposition of the sodium ferrocyanid upon evaporating the solution.

PROCESS OF MAKING SULPHURIC ACID.

Rudolf Knietsch, of Ludwigshafen-on-the-Rhine, Germany, assignor to Badische Anilin und Soda Fabrik. Patent No. 800,218, dated September 26, 1905.

In the specification of Letters Patent No. 652,119 is described a catalytic process for the production of sulphuric acid, in which process the gases from the pyrites-burners are before their combination to sulphuric anhydrid thoroughly purified from all injurious impurities, and finally an acid is obtained which is entirely free from arsenic, nitrous compounds, and lead. The commercial acid obtained by this process contains as sole impurity a small quantity of iron. The iron is introduced owing to the practical necessity of effecting the absorption of the sulphuric anhydrid first formed in iron apparatus. The present invention provides an improvement in this manufacture whereby commercial sulphuric acid can be obtained directly, which acid is for technical purposes practically free from iron-that is to say, can be obtained with only .003 per cent. of iron, or even less. This result is effected by absorbing the sulphuric anhydrid in a fuming sulphuric acid containing about twenty-s -seven per cent. of free sulphuric

anhydrid or more—that is, is an acid of minimum strength corresponding to the composition approximately represented by the formula 2H2SO + SO. This does not dissolve wrought iron and the absorption may be effected in a wrought-iron apparatus that can be kept cool.

PROCESS OF PRODUCING TERPENES AND RESINOUS SUBSTANCES.

George P. Craighill and George A. Kerr, of Lynchburg, Virginia, assignors to N. C. Manson, Jr. Patent No. 800,905, dated October 3, 1905.

In this process the wood after being reduced to chips or shavings is placed in a suitable digester and thoroughly saturated with an alkaline solution of one per cent. The solution dissolves the resinous contents of the wood and opens up the cells thereof, so that upon the application of steam the terpenes are liberated with great freedom and rapidity. The alkaline solution has also the property of fixing the various volatile acids and oils, which would otherwise pass off with the terpenes. For this purpose preferably use a solution of sodium hydroxid, (NaOH,) although a solution of sodium carbonate (Na2CO3) may be employed. After the wood has been thoroughly saturated with the alkaline solution, steam is admitted to the mass, and in this way the terpenes are volatilized and made to pass off with the steam from the top of the digester. The mass is heated to a temperature of from 100° to 110° C., since any temperature in excess will not result in the production of good turpentine, the best results being secured by subjecting the mass to a low temperature. The acids and oils of the wood being fixed, the volatilized terpenes are recovered from the condenser in a pure and colorless state. They may while volatile be passed through a bone-black filter to secure terpenes of a high grade.

After the steam-supply is discontinued a sufficient quantity of water is added to submerge the wood, and the solution containing the rosin is drawn off. The rosin, free from tarry and oily

products, is subsequently recovered from this solution, that in suspension by precipitation, and that in solution either by neutralizing the alkali or by evaporation. When the extraction of the wood is effected by destructive distillation or when digested with any strong chemical reagents, the recovered resinous substances are not free from these tarry and oily products.

PROCESS OF NITRATING AROMATIC AMINS. Wilhelm Herzberg and Eduard Thon, of Berlin, Germany, assignors to Actien Gesellschaft für Anilin Fabrikation. Patent No. 800,913, dated October 3, 1905.

This process consists in heating with diluted nitric acid the socalled "arylsulphamids "-i.e., a sulpho derivative of an aromatic primary or secondary amin. These products are obtained by the reaction of benzene-sulpho-chlorid or para-toluene-sulpho-chlorid upon primary or secondary amins of the benzene series, their derivatives or homologues, so that the simplest form of the products to be nitrated is represented by the formula.

CH.NR.SO2.C&H4.R1.

R standing for the hydrogen atom or methyl, ethyl, &c., and R1 standing for the hydrogen atom or the group CH. The nitration of such compounds was hitherto performed in a solution in concentrated acetic acid by the action of concentrated nitric acid. This method is not adapted for industrial purposes because it is a very expensive one and does not yield a uniform product, dinitro derivatives being produced besides mononitro compounds. Also the usual manner of nitration-i.e., by nitrating in concentrated sulphuric acid-is not advantageous, decomposition takes place.

The nitro derivatives obtained according to this process are nearly chemically pure, and therefore immediately fit for use in manufacturing other products—as, for instance, dyestuffs-because only the benzene nucleus annexed to the NH, group is attacked by the nitric acid. Moreover, only one nitro group enters this benzene nucleus and takes, in every case, the para

position to the NH2 group, so that no waste products occur with our process. The yield, therefore, is a nearly theoretical one.

PROCESS OF MAKING CAMPHOR.

Karl Stephan and Paul Hunsalz, of Berlin, Germany, assignors to Chemische Fabrik auf Actien (vorm. E. Schering). Patent No. 801,483, dated October 10, 1905.

It is known that borneol or isoborneol can be transformed into camphor by such oxidizing agents as chromic acid, permanganate, and the like. All these processes have the drawback that the products formed by the reduction of the oxidizing agent-for example, salts of chromic oxid-are mixed with the camphor and render its purification more difficult. Camphor may, however, be obtained without difficulty and without any troublesome admixture when ozone is used as the oxidizing agent. It was by no means obvious that the oxidation could be produced without difficulty by means of ozone. Apart from the fact that by no means all oxidizing agents are successful, the action of manganese and sulfuric acid upon isoborneol, for example, producing mainly aldehydes, it was to be expected that the use of ozone might lead to the formation of additive products which by reason of their tendency to explode would have rendered the process technically impossible. Further, it may be remarked that while other oxidizing agents transform the camphene into camphor the action of ozone upon camphene produces no camphor, but only camphenilon and formic aldehyde.

PROCESS OF MAKING CAMPHOR.

Karl Stephan and Paul Rehländer, of Berlin, Germany, assignors to Chemische Fabrik auf Actien, vorm. E. Schering. No. 801,485, dated October 10, 1905.

Patent

The inventors have discovered that camphor may be produced by oxidizing borneol or isoborneol by means of oxygen or air with or without the use of so-called " catalytic" reagents.

The process consists in treating borneol or isoborneol vapors

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