USRE10667E - Constantin fahlberg - Google Patents

Description

UNITED STATES CONSTANTIN FAHLBERG, OF NEW YORK, N.Y., ASSIGNOR or ONE-HALF TO ADOLPH LIST, OF LEIPSIGRGERMANY.

I MANUFACTURE OF SAOCHARINE COMPOUNDS.

SPECIFICATION formingpart of Reissned Letters Patent No. 10.667. dated December 1, 1885,

Original No. 319,052, dated J une 2, 1815. Application for reissue flied JulytlS, 1685. Serial No. 112,697. Patented in Belgium August 16, 1884, No. 60,048, and in France August 16, 1884, No. 161,197.

To all whom it may concern:

Be it known that I, Coss'murm FAHLBERG, of the city, county, and State of New York, have invented a new and useful Compound called Saccharinc, and Process of Manufacturing the Same, as hereinafter fully described.

My invention relates to the manufacture of a saccharine compound from toluene and other derivatives of coal-tar, which compound contains the elements of carbon, hydrogen, oxygen, sulphur, and nitrogen, and possesses a similar sweet tasteas saccharose or cane sugar. It may be used for many purposes where sngar would be too costlyfor instance, in sweetening glucose, grape or starch sugar, and for other purposes where cane sugar is used for sweetening and preserving purposes.

The invention is based upon't-he original researches published by myself in the American Chemical Journal, 'Volumel, Nos. 2 and 3, June, 1879, pages 170 to 17,-"), andjointly by myself and Ira Remsen, in the same journal, Volume 1, No. 6, pages 426 to 438, in which a saccharine compound was first described, to which the name of henzoic sulphinide was given. V

The object of this invention is to provide a process by which said saccharine compound can be manufactured on a large scale, and cheap enough to be used in the arts.

The special characteristics of the compound are its sweetness and antiseptic properties.

The high antiseptic properties of my improved sacchatiue compound will recommend it 1'or many purposes int-hearts and medicine. Owing to the fact that it cannot be classed undcrtheheading oi nourishments, like sugar and similar carbon hydrates, it may be used for many medical purposes in which canesugar is excluded from the diet, as in the case of diabetesmellitus, and other diseases.

Myimprovcd compound does not dissolve easily in cold water. It is more soluble in warm or hot water, and can be easily obtained from its ai' ueous'solution in crystalline form. Alcohol and ether dissolve it readily It crystallizes in thick shortprisins, in all probability belonging to the monocln'ne system. The crystals, however, are small and not well fo med, f es'at about 200 centigrade under partial decomposition. saccharine possesses a. marked sweet taste, being much sweeter than cane -sugar and sweeter than grape or starch sugar; Adiluted solution of the compound tastes like asaturated solution of cane-sugar.

In an aqueous solution my improved saccharine compound forms readily salt-like com- .pounds with the alkalies, alkaline earths or metals,similar to cane-sugar. These salts possess the same pleasant sweet taste as the compound itselt. All salts of the compound crystallize badly, those of the alkalies yielding on evaporation asirup-like mass,which is unable to crystallize even after long standing.

The saccharine compound forms. under cer: tain conditions, with the residues of the hydrocarbons, as methyl, ethyl, propyl, &c., compounds which are termed csters, possessing the same sweet properties as the primary compound.

' The saccharine compound beingaderivative of benzoic acid does not ferment like grapesugar and other carbon hydrates.

Having described so far the properticsand advantages of my new sweet compound, to which I have given the name saccharine, I shall now proceed to describe the process of its preparation.

Operation 1: Saccharineis prepared from coal-tar and similar products,'in particular from such products containing abundantly benzinc, toluene, xylene, &c. Although toluene generally is used for-economical reasons,

other substitution products of benzine and the like, which yield on oxidation, or which contain without previous oxidation beuzoic acid, may be used. Toluene is firsttreated with fuming sulphuric acid in the cold, or with concentrated sulphuric acid, at atemperature of 220 Fahrenheit, and above, in leaden vessels until it is dissolved, respectively converted into the two isomeric tol uene-monosul phonic acids. It has been found, however, that strong concentrated sulphuric acld,or a mixture of hydrated sulphuric acid and anhydrous sulphuric acid is better adapted for this purpose, inasmuch as the yield of saccharine was larger than when fuming sulphuric acid was used.

Operation 2: As soon as the last trace of 2 '10, car

into the salts of the alkalies by means of any.v

l of the known carbonates of the alkalies-for ene-monosnlphonatcs- -by using a carbonate or'bicarhonate of sodium. The carbonate of lime resulting from this operation can be filtered off by a filter-press, and used again in the second operation in place of ordinary chalk. This quantity of carbonate of lime would be suflicient for a continuous preparation of calcium tolueue-sulphonate had it not'been' for a 5 tion 1, which is to be neutralized with fresh quantities of chalk.

Operation 4: The resulting solution of the sodiuntsnlt is evaporated in open or vacuum pans until on cooling it becomes hard. The

contents of the pan are then solidified by run- 'ning them into iron or wooden molds. The

lumps are chipped or broken by hand or machines and placed in a drying room. To besure that all the water from the sodium .salt is removed, itis dried afterward by. steam in convenient. drying apparatus.

Operation 5: As soon as the sodium salts are found to be perfectly dry they are treated this purposefwith phosphor-pentachloride (most conveniently made by a method hereinafter described) in proportions to eflect-a complete transformation. The products formed by this operation will be two isomeric tolucnemonosulphochlorides and ph osphoroxychloride. The latter is'removed hy distillation, collected and used in the preparation of phosphorpentachloride, while the former,

snlphochloride. are separated in a centrifugal machine or other equivalent apparatus. A frequent washing with cold water in the cen trii'ugal machine is essential to efi'ect a complete separation of the two toluene-sulphachlorides, inasmuch as the'saccharine is only instance, into the corresponding sodium toluan excess of sulphuric acid required in opera-'- in an apparatus especially constructed for,

consisting of a'sdlid and a liquid toluene-V a centrifugal machine, and finally converted into the amid.

Operation 6: Theliqnid toluene-sulphochloride is converted, either by causticor carbonate of ammonia. preferably by the latter, into to lueno sulphamid. For this purpose'the liquid sulphochloride and. the solid carbonate of ammonia are mixedttogether in proper proportions and exposed to heat, so as to effect the transformation, during which carbonicacid gas is given off. The remaining mass contains the amid with a certain quantity of ammonium chloride. I

Operation 7 The amid, after-being separated by acentrifngal machine, is oxidized by means of any of the known oxidizing agents in an alkaline solution, and yieldsasalt of saccharine, which corresponds with regard to its base to the base of the oxidizing agent. Such oxidizing agents are tnmerous; but preferably permanganates and plumbic dioxide are used In making use of the permanganates the result of the oxidation will be a salt of saccharine, hydrated manganese dioxide. and a free alkali or a-carbonate of an alkali. The insoluble. hydrated manganese dioxide can be easily separated from the alkaline solution containing the salt of saccharine by means of afilter or any other convenient method, and converted by any of the known methods into permanganates and usedfor subsequent oxidkaline solution containing the'salt of sacchatime can be neutralized by an acid, and finally evaporated to any desired consistency. The

ation of toluenersnlphamid. The slightly altoo slightly impure product will be found topossess a pleasant sweetness. In order to prepare the pure saccharine therefrom, the concentrated solution of the salt is treated with eitherhydrochloric or sulphuric acid and the precipitat-e dissolved and crystallized. this waya colorless and finely-crystallized p'roduct of characteristic sweetness. The precipi tation with strong acids is connected with great loss, caused by the decc'vmpositiomof saccharine in the presence of strong, mineral acids. A better method to obtain saccharine in larger quantities and of higher purity con-- sists in the employment of plumbic dioxide as an oxidizing agent. The plumbic dioxide can be easily obtained from either sulphate of lead or basic chloride of lead by oxidation with hypochlorite' and carbonate of sodium. Having prepared in such a way the plumbic dioxide, it is washed and then ready ior use.

Ityields in Tolnene-sulphamid-and plumbic dioxide are mixed. together with suflicient water and heated by steam until the toluene-sulpham-id has become completely converted into the leadsalt of saccharine, while the plumbic dioxide is converted into litharge. taining the lead salt is treated with hydrogen sulphide, in order to precipitate thelead as lead sulphide. saccharine is then separated fromthe precipitate by means of any convenient .filter, and

. yields on cooling crystals of pure saccharine.

The hot saturatedsolution of t The solution con-- The motherliquors resulting from the crystallization are used for the oxidation of toluenesulphaniid in place of water to-save the expense of evaporation, which in the case. of the permanganate process would be comparatively large. The lead sulphide and the litharge are made use of in the preparation of fresh quantities of plumbic dioxide. The former is roasted for this purpose in a furnace and converted into sulphate of lead. The latter,however,is treated with chloride of sodium and converted into basic chloride of lead.

which latter yields, by oxidation with hypochlorite and carbonate of sodium, plumbic dioxide, as hereinbefore described.

From the pure saccharine difierent salts can be prepared by treatment with the corresponding carbonates in an aqueous solution. saccharine. may also be prepared by oxidizing the two toluene-sulphonic acids or their salts with any 'of the above-named oxidizing agents into sulphobenzoates, and further treatment with phosphor-pentachloride and caustic or carbonate of ammonia. The final result of such a treatment will be the formation of an insoluble diamid of sulphobenzoic-acid and the ammonium salt of saccharine.-

The way in which saccharine in its pure state is obtained from its salts has already been described.

The phosphoroxychloride, resulting from the fifth operation, contains nearly three-fifths part of the total chlorine and all the phosphorus of the phosphor-pentachloride, and is used in the manufacture of phosphor-pentachloride from phosphorus and-bleaching-powder (hypochlorite of calcium) by conversion with water into hydrochloric and phosphoric acids. The hydrochloric and phosphoric acids are used for generating chlorine from bleaching-powder. The phosphate of lime and calcium chloride left in the generator may be separated and the phosphate of lime used as a fertilizer. In other respects the old and well-known process of making phosphor-pentachloride from phosphorus is not altered. The solid toluene-sulphochloride, amounting, by wei ht, to about two-thirds of the total bulk of t e toluene-sulphochlorides, is mixed with carbon and moistened with water and converted under pressure in a retort into hydrochloric and toluene-sulphonic acids. On passing superheated steam over this mass toluene and hydrochloric and sulphurous acids are obtained. Toluene is used in operation 1, while hydrochloric and sulphurous acids are profitably employed in the separation of saccharine from its salts when the permanganate process of oxidation is used.

The final product of the process described is the new saccharine compound benzoic sulphinide, the chemical formula of which is C,H,.O,SN, and which has the characteristic.

' properties described in'the publications hereinbefore set forth. Having thus described my invention,Iclaim as new and desire to secure by Letters Patent- 1. The process of making a new sweet compound from toluene and other derivatives of coal-tar, whichconsists of the following successive steps: first, converting toluene and the substitution products of bcnzine audits homologues into toluene-monosulphonic acids by fuming or concentrated sulphuric acid; second, converting the tolucne-nionosulplionic acids into calcium toluenemonosulphonatcs by chalk or carbonate of lime; third, converting the calcium tolnene-monosulphonatcs by sodium carbonate or bicarbonate,or any other carb'onate of the alkalies, into sodium toluenemonosulphonate or any toluenc-monosulphonate of the alkalies; fourth, evaporating the sodium toluene-monosulphonate in open or vacuum pans and cooling and dryingthe same; fifth, converting the dry product into 2. The process of making a new sweet com-- pound from toluene and other derivatives of coal-tar. which consists in converting toluene into toluene-sulphonic acid, oxidizing said acid or its salts into sulphobenzoic acid or its salts, then evaporating the latter and trtating it with phosphorpentachloride and caustic or carbonate of ammonia, and finally separating the pure saccharine from the ammouiu m salt thus obtained, substantially as set forth.

3. The regeneration of toluene and the generation'at the same time of hydrochloric and sulphurous acids from the solid toluenemonosulphochloride by the action of carbon, water, and superheated steam under pressure, substantially as described.

4. The generation of chlorine for the prep-.1- ration of phosphor-pentachloride from phosphoroxychloride, bleaching-powder, (hypochlorite of lime,) and water, respectively, hydrochloric and phosphoric acids, or one of them, substantially as set forth.

5. The saccharine -compouud, benzoic sulphinide, substantially as described.

6. The saccharine compound, benzoic sulphinide, made by the process herein described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

oonsran'rrn FAHLBERG.

Witnesses:

MARTIN PETRY, SIDNEY MANN.v

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