XI. o-Sulphobenzoic acid and acetonitril yield a compound isomeric with saccharin which may be the unsymmetrical o-sulphobenzimid.

XII. By varying the conditions three of the four possible imids of mellitic acid were produced by heating this acid with acetonitril. The p-euchronic acid is a new compound; o-euchronic acid and paramid were known but have resulted also by our nitril reaction. It has been shown that aluminum amalgam can be used to give the euchron test.

To sum up then briefly, I believe I have made three new imids; viz., malonimid, p-euchronic acid, and an imid of sulphobenzoic acid. The known imids of succinic, phthalic, homophthalic, diphenic, and mellitic acids have been made by a new method. The conclusions of Colby and Dodge, stated in the introduction, have been confirmed and the first method used by Miller and Seldner for producing fatty imids has been found applicable for producing aromatic imids. The widest general conclusion to be drawn from the work of these earlier investigators of the action of nitrils upon acids and from my own work is that when acids and nitrils are heated together they tend to form disubstituted ammonia compounds, secondary amids from monobasic acids and nitrils, imids from dibasic acids and nitrils.

ORGANIC LABORATORY, HAVEMEYER HALL,

COLUMBIA UNIVERSITY.

[CONTRIBUTIONS FROM THE HAVEMEYER LABORATORIES OF COLUMBIA UNIVERSITY, No. 2.]

THE ACTION OF METALLIC THIOCYANATES UPON ALIPHATIC CHLORHYDRINS.'

TH

BY WILBER DWIGHT ENGLE.

Received July 7, 1898.

HE alcohols form the most important class of organic compounds which have no representatives containing the thiocyan group. It would seem that such compounds would be produced by the double decomposition between alcohols having one or more atoms of hydrogen displaced by halogen and a metallic thiocyanate, and it was with this expectation that the following experiments were undertaken. In all cases tried, a reaction occurred as was shown by the separation of the halogen

1 Read at the meeting of the New York Section, May 6, 1898.

to be very

salt. The thiocyanates formed, however, seem unstable, easily changing to resinous substances, and much difficulty was experienced in separating and purifying them. In some cases it was found impossible.

The particular thiocyan alcohols, whose preparation was undertaken, are those derived from propane; namely, a-thioCH,SCN

CH,SCN

cyanhydrin, CHOH, a, ß-dithiocyanhydrin, CHSCN, and a,y

dithiocyanhydrin, CHOH. As being of a somewhat similar

hydrin, CHSCN

CH2OOC,H,

were prepared.

, and B-acetodithiocyanhydrin, CHOOC,H,,

α-THIOCYANHYDRIN.

CH,SCN

For the attempted preparation of a-thiocyanhydrin the corre

CH2C1

sponding a-chlorpropylene glycol or monochlorhydrin, CHOH,

was used.

CH,OH

A mixture of fourteen grams of monochlorhydrin and thirteen grams of potassium thiocyanate, with ninety-five per cent. alcohol for solution, were heated on the water-bath with a return condenser. A crystalline precipitate of potassium chloride gradually formed. After four days of heating, four grams of potassium chloride in place of ten grams, theoretical quantity,

had separated. The filtrate from the potassium chloride was again heated. Only a little more of the chloride separated but there formed a considerable amount of a white resinous substance, some of which was removed from the flask and examined. Washed with hot water and alcohol it is a white or light yellow, brittle, odorless substance. It is insoluble in ordinary organic solvents, including water, alcohol, ether, benzene, chloroform, carbon disulphide, benzine, kerosene, gasolene, and toluene. It is unaffected by hydrochloric, acetic, and sulphuric acids or by ammonium hydroxide or strong aqueous potassium hydroxide. Bromine decomposes it with the production of a tar-like substance. Strong nitric acid oxidizes it, producing sulphuric and oxalic acids. This is an interesting reaction since it shows that the sulphur is much less closely bound to the radical than in the case of thiocyanates, mercaptans, and sulphides which, by oxidation with nitric acid, yield sulphonic acid, sulphoxids, and similar compounds.

That this resinous substance is not a thiocyanate is shown by the following facts: It does not give a sulphide with potassium hydroxide. It does not give a mercaptan with zinc and sulphuric acid. It does not give a sulphide and potassium thiocyanate with potassium sulphide. It does not give a sulphonic acid by the oxidation with nitric acid. Its solubilities are not those of known thiocyanates.

An analysis of the substance carefully washed with water and alcohol and dried to a constant weight, gave the following percentages, from which it is impossible to calculate any simple formula:

These percentages indicate that a secondary reaction has produced a complex condensation product. The absence of any solvent prevented any attempt to crystallize this compound. flask, containing a mixture of potassium thiocyanate and monochlorhydrin, after heating was set aside. After several weeks it

was examined and well-formed crystals were found. The properties of these crystals were identical with those of the substance just described.

Besides the insoluble white substance there was also found, in the alcoholic filtrate from the potassium thiocyanate and monochlorhydrin, a very small amount of oil having the garlic odor characteristic of the organic thiocyanates. This oily liquid is extremely unstable. Any attempt to purify it changes it to the insoluble white substance. Apparently the monothiocyanate is first formed by the reaction, and by some secondary condensation the insoluble compound results.

The reaction between potassium thiocyanate and monochlorhydrin was also tried at higher temperatures. Sealed tubes containing these two compounds in the ratio of their molecular weights, with alcohol as a solvent, were heated to different temperatures. Below 100° the action was very slow. From 110° to 115° the reaction was complete in six hours. At 120° and above there was much decomposition. In all cases the products are the same: the insoluble white compound and a trace of what was considered the monothiocyanhydrin. It was impossible to secure this in amount sufficient for further study.

a, B-DITHIOCYANHYDRIN.

CH,Br

The a,ß-dibromhydrin, CH Br

to be used in the prepara

CH,OH

tion of a,ẞ-dithiocyanhydrin, was obtained by the direct addition of bromine to allyl alcohol,

C,H,OH + 2Br = C,H,Br2OH.

The product was purified by distillation in vacuo.

An alcoholic solution of forty grams of this dibromhydrin and thirty-seven grams of potassium thiocyanate were heated on the water-bath for six days. Somewhat more than half the theoretical quantity of potassium bromide separated. As there were signs of decomposition the heating was stopped. By evaporation of the alcohol, washing with water, and collecting with ether, about ten cc. of a dark-colored liquid was obtained.

Heated with potassium sulphide solution it gave potassium thiocyanate easily identified by the ferric chloride test. On heating or attempting to distil with steam it was resinified.

The reaction was next tried in sealed tubes. The tubes were charged with potassium thiocyanate and dibromhydrin, in the ratio of two molecules of the former to one of the latter. Alcohol was added as a solvent. Between 110° and 115° the reaction was complete in about eight hours. At higher temperatures there was much decomposition. In all cases there was a tendency to produce an amorphous substance similar to that from the monochlorhydrin. The contents of the tube were treated with warm alcohol. The alcoholic solution filtered from the potassium bromide was slowly evaporated to a small bulk and carefully washed with water to remove any unchanged potassium thiocyanate. There was left an oily liquid which could be further purified by solution in ether. This treatment does not remove all the unchanged dibromhydrin. The compound decomposes on heating, hence cannot be distilled. The difficulty of securing a pure sample prevented analysis. That the liquid is dithiocyanhydrin is shown by the fact that it gives potassium thiocyanate on heating with potassium sulphide, and the yield of potassium bromide is nearly equal to the theoretical. Additional proof is found in the preparation from it of iminomethanepropylalcohol disulphide hydrochloride of the formula

A similar reaction is found in the case of methylene dithiocyanate and propylene dithiocyanate. Both compounds have adjacent thiocyan groups as in the case of the compound under discussion and both give imino compounds similar to that above.'

About ten cc. of dithiocyanhydrin was poured into fifty cc. of water and a few grams of granulated tin added. The mixture was carefully heated on the water-bath and hydrochloric acid. added. In the course of an hour's boiling the oily dithiocyan1 Hagelberg: Ber. d. chem. Ges., 23, 1083.