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United States Patent 0 Patented Nov 2,695,310 United States Patent 0 Patented Nov. 23, 1954 v 1 2 as in Reaction 2 above, the inner salt B-S-thiuronium 2,695,310 ethanesulfonate is formed, together with the metal halide salt from which it may be separated to obtain pure PREPARATION OF GUANIDINIUM ?-s-thiuronium ethanesulfonate. The reaction is pro MERCAPTOALKANESULFONATE moted by heating a solution of the two reactants in any inert reaction medium such as water, preferably in about Charles H. Schramm, Wellesley, and Roy H. Karlson, molal proportions, at a temperature of from 150° F. up Newtonville, Mass., assignors to Lever Brothers Com to a gentle boil for a period between about one and three pany, New York, N. Y., a corporation of Maine hours and allowing the solution to stand, generally for No Drawing. Application December 12, 1951, 10 several hours at room temperature or lower to permit the Serial No. 261,378 crystalline precipitate of the ?-S-thiuronium ethanesul fonate to deposit from the solution. The [3-S-thiuronium 25 Claims. (Cl. 260-501) ethanesulfonate may be puri?ed by recrystallization from water or other solvent. The puri?ed p-S-thiuronium This invention relates to certain novel compounds and etnanesulfonate product does not possess a sharp melting to novel processes for their preparation. point but decomposes upon heating to 265° C. The It is an object of our invention to prepare new and p-S-thiuronium ethanesult'onate is then reacted with useful sulfur- and nitrogen~containing organic compounds aqueous ammonia as in Reaction 3 above to form the by means of the novel processes described more fully pure single product of guanidinium B-mercaptoethane hereinafter. The compounds of the invention are pre 20 sult'onate which is believed to be a novel compound. pared by a novel combination of steps, some of which are The reaction is promoted by heating the reactants in sub also novel. The compounds, which result from the dif stantially molal proportions on a steam bath to promote ferent steps will be described more fully hereinafter. - The an exothermic reaction. A temperature of 105 to 150° F. novel compounds are all useful as intermediates for the may be used and the time required is about one to three preparation of other compounds. 25 hours. Any inert solvent, preferably water, may be used. The general reactions and the compounds produced The reaction mixture is concentrated preferably under thereby may be seen from the following equations: vacuum after standing for several hours and the residue crystallizes on cooling. The white salt may be recrystal~ (1) X(GH2),.X + MezSO: —> X(CHz)mSOaMe + MeX lized rrom anhydrous alcohol to give a wnite crystalline di-haloalkane haloalkane-sulfonate 30 product with a melting point of 109-172” C. The literature contains examples of treatment of bro (2) + NH: mides and iodides of thiuronium compounds with am \ 6 monia or amines to yield mercaptans and guanidines. X(OHz)..SOsMe + NHzCSNH; -—> /C—S—(CHz)..SO5 + MeX This is to be'distinguished from the reaction of thiuronium 35 compounds of the inner-salt type such as ,B-S-thiuronium ’ NHI' etnanesulronate in accordance with theinvention. We haloalkane- thiourea S-thiuroninm sulfonate alkanesult‘anate have found the reactions reported heretofore do not occur when the inner salt is used; but, on the other hand, (s) a novel reaction is obtained which produces a single addi + 40 tion product containing a guanidinium radical, not pre NH: NH: viously prepared. \ 9 ' e + / The guanidinium compound is especially useful as an C—S—(CH2) "SO; + NH;(aq.) —) HS(CH2) nSO8NH2=C intermediate in the preparation of other chemical com NE: NH: pounds, and due to the fact that it is formed by the S-thiuronium guanidinium mercapto 45 present process without any contaminating impurities or alkanesulionate ‘ alkanesultonate extraneous products, the preparation and recovery of its derivatives are greatly simpli?ed. In most instances, the where X is a halogen, preferably bromine vor chlorine, resulting guanidinium compound may be used as formed n is a small whole number between 1 and 5, preferably 2, in the reaction without further puri?cation. and Me is an alkali metal preferably sodium. For con 50 The guanidinium mercaptoalxanesulfonate product of venience, the process will be further referred to as illus Reaction 3 above may be converted to the corresponding trative when X is bromine, n is 2, and Me is sodium. salts of other bases by one of several methods. For ex It will be appreciated that any water-soluble sul?te may ample, it may be converted by means of the double de be employed in Reaction 1 in place of the metal sul?te composition with a nitrate salt such as ammonium or shown above. Due to certain economic factors, sodium .. sodium nitrate, taking advantage of the low solubility of or potassium sul?te is usually employed. The water guanidine nitrate which is formed by the double decom soluble metal metabisul?tes, such as sodium metabisul?te, position reaction in which the guanidinium radical of the may also be used in place of the sul?te in Reaction 1. guanidinium sulfonate salt is replaced. However, a more However, in the latter cases, it is necessary to add a satisfactory process which also permits the preparation mole of the metal hydroxide, such as sodium hydroxide, of the free sulfonic acid is by means of a cation resin per mole of metabisul?te. It has been found advisable’ exchange treatment in which an aqueous solution of not to add the sul?te in greater than SlIOlChlOIIl?tI'iC. guanidinium mercaptoalkanesulfonate is passed through quantities to the Reaction 1 since the presence of excess a cation exchange resin whereby the guanidinium ion is sul?te favors the formation of undesirable disulfonates. replaced by a hydrogen ion to form mercaptoalkane Furthermore, amine compounds, other than ammonia, 65 sulfonic acid in accordance with the reaction: such as methylamine, monoethanolamine, etc., may be (4) N32 . Q used in Reaction 3 above. In such cases the product will, 9 + / + of course, be the corresponding substituted guanidinium HS(CHi)nSOaNHr-—C + H——(lon resin) -—-> mercaptoalkanesulfonate. Reaction 1 has been described in the literature in an ,7 . - 7 NH: article by I. M. Lipovich, J. Applied Chem. (USSR) 18, 70 guanidinium mercaptoalkane 718-24 (1945); Chem. Abs. 40, 6407 (1946). In this sulfonate experiment, the investigator puri?ed a resulting bromo NH; ethanesulfonate compound and converted it with sodium I \ + hydrogen sul?de (NaSH) to the sodium Z-mercapto HS(CHa),.SOaH + C=NHI—(1OD resin) ethanesulfonate. In an example employing the halo N a ethanesulfonate in accordance with our invention, we do mercaptoalkane not employ sodium hydrogen sul?de but rather react suliom'c acid the sodium haloethanesulfonate salt with thiourea. This where n is _a whole number. process is believed to be novel. We have found that by 80 Any cation exchange resin possessing strongly acid reacting the sodium haloethanesulfonate with thiourea groups is satisfactory for use in converting the guani ‘2,695,310 3 4 dinium sulfonate salt into the corresponding sulfonic 500 cc. of water. were heated in a 2-liter beaker on an’ acid. Examples of suitable cation resin ‘exchange mate‘ ‘electric hot plate until solution was effected. A hot ?ltra rlals are the nuclear sulfonic type cation resins such as tion removed suspended extraneous material after which the commercial Amberlite lift-120, Arnberlite iR-lOO, the clear solution was heated to a gentle boil for an addi and Dowex—50»' which are corrimercially available on the tional hour. At the end of this time the solution was market. ~ allowed to stand at room temperature overnight. In this 1 The mercaptoalkanesul-fonic acid obtained will be ex way, there was obtained 230 g. of B-S-thiuronium ethane tremely pure, an important factor because the oxidation sult'onate as a crystalline precipitate, which was recrystal or mercaptans ‘is catalyzed by the presence of small lized from water. This represents a 65% yield based on amounts of impurities. The acid can be used» directly-in ethylene dibromide. The compound does not possess a the‘ preparation or" derivatives of the sulfonic acid». For sharp melting point but was. decomposed upon heating example,‘ the sulfonic acid ‘may be reacted with various to 265° C. basic compounds to form the corresponding salts. For The above ‘experiment was repeated with satisfactory example, mercaptoe'thanesulfonic acid can be ‘reacted with results by placing the same total quantities of ethylene di monoethanolamine in an addition reaction to prepare bromide, alcohol, water, and sodium sul?te together in monocthanolamine B-mercaptoethanesulfonate as fol the ?ask and re?uxing the mixture for one hour and lows: ‘ ’ then allowing the reaction mixture to distill until the residual solution was concentrated to 11/2 liters. The un HSCHzCHzSOsH+H2NQH2CH2DH§ _ . I reactcd ethylene dibromide was recovered ‘from the dis ' HSGHzCH2S0sNI-I3CH2CH2OH .20 tillate. ‘ ' in a similar addition react-ion ?-mercaptoethanesulfonic EXAMPLE 2 acid can be reacted with ‘ethylamine ‘to form the corre Guanidinium ‘B-merc'aptoethanesulfonate?-Two. hun sponding ethylamine B-rnercaptoethlanesulfonate as fol—' dred and thirty gramsof ,B-S-thiujrbnium ethanesulfonate lows: ' ‘ was placed in a 1-liter round-bottom ?ask. To this there HSCHzCHzSCaH-I-QhiaCHéNHt-X _ . was added 500 cc. of concentrated aqueous ammonia, I-lSCHzCHzSOBNHsCH2CH3v and the reaction mixture was heated on ‘the steam bath. An exothermic reaction ensued within a short time at " The mercaptoalkanesul'fonic acids can ‘also be reacted which point the reaction- was removed, from the steam with mineral bases to form corresponding salts-,ofthe sul bath and allowed to stand at room‘ temperature.
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