Reactivity of Substituted Thioureas with Inorganic Ions JOHN H. YOE AND LYLE G. OVERHOLSER University of Virginia, Charlottesville, Va.
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HE examination of the reactions of 60 substituted thioureas with 78 inorganic ions was undertaken t o ascertain whether or not a n y of these reactions might be more sensitive than those given b y thiourea, especially for bismuth. The results presented in this paper show that the substituted thioureas-i. e. , compounds containing the reactive group =N-C-K=, give reactions similar t o those of
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thiourea and t h a t although a number of the reactions are as sensitive, or even slightly more sensitive for bismuth, they offer no advantage t o justify their use in place of thiourea. An attempt was made to correlate the reactivity or nonreactivity of certain ions with the structure of the various substituted thioureas. Because of the similarity of the reactivity no definite conclusions could be formulated. T h e differences in solubility of the various substituted thioureas undoubtedly play a more important part in their reactivity than does the presence of a n y particular substituted group. Moreover, no correlation of sensitivity and structure appears to be possible. T h e reactions and the sensitivities of t h e more sensitive ones are given for the substituted thioureas, as well as those for thiourea.
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The experiments were performed on a spot late by adding 1 drop of the solution of the reagent to 1 drop o!the solution containing the inorganic ion. The reactions were carried out in aqueous, acid, or ammoniacal medium. Solutions containing 1 mg. per ml. of the following 78 ions were used. (It is recognized that some of the ions are more complex than is indicated by the formulas in this list.): Ag+, Al+++, AuCla-, As++T, As04---, B40,--, Ba++, Be++ Bi+++ BrCe+++-!C1- Fe++-r' bo++' CO-- Cs+, Ca++dU++, Cb04--Cd++ Ce+++ Cr+aL+: Dy+J+, Er+'++, Eu+'++, F-, Fe++, j
Ga+i+, Gd+++, Ge"+++ (0.5 mg. per ml.), Hf+++' (0.25 mg: per ml.), Hg,++, Hg-+, I-, In+++, IrCl6--, K+, La++T, Li', hIg++, Mn++ Rlo04-- NOz- NO,-, Na+, Nd+++, Ni+', OqO5-- HPO,'-- Pb++ PtClG--' Pi-+++ Rb+, Reo4-, RhC15--, Sb+++, Si+++,s&&-, Sioa--, Sm+++, Rkl,-,' S--,Sd,---, Sn++, Sn++++ Sr++, TaO,---, Te04--, Ti++++, Th+'++, VO+, R04--, Y+++, Yb+++, Zn-+, T1+, Tm+++, bol++, Zr++++. An alcoholic solution of the reagent containing 10 mg. per ml. n-as used where the solubility permitted; otherwise a saturated solution was employed. The reagents were obtained from E. I. du Pont de Kemours 8: Co., Inc., and the Eastman Kodak Co. and were used without further purification. The reactions of the following 60 substituted thioureas were observed: 1 . Allylthiourea 2. hlonolaurylthiourea 3. Dilaur ylthiourea 4. s-Diethylthiourea 5 . Di-n-butylthiourea 6. Phenylthiourea 7 . Benz ylthiourea 8 . o-Tolylthiourea 9. n-Tolylthiourea 10. p-Tolylthiourea 11. Xylidylthiourea 12. 2-Carboxyphenylthiourea 13. o-Chlorophenylthiourea 14. p-Hydroxyphenylthiourea 15 m-Nitrophenylthiourea
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44. s-Di-m-tolylthiourea 45. s-Di-p-tolylthiourea
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46. s Di(2 methoxy 5 methylphenyl) thiourea 47. Phenyl-o-tolylthiourea 48. Diethoxydiphenylthiourea 49. N,Ni-di (p-n-propyloxyphenyl)thiourea 50. X , N l - di(p - bromophenyl) thiourea 51. N , N 1 di(p fluorophenyl) thiourea 52. S,.Vi d i ( p hydroxyphenyl) thiourea 53. N , N 1 d i ( p aminophenyl) thiourea 54. X,.V1 di(p acetylamino phenyl) thiourea N,N1 - d i ( n trifluoromethyl 55 phenyl) thiourea 56 m-Phenylenedithiourea 57 p-Phenylenedithiourea 58 Benzidinedithiourea 59 Tolidinedithiourea 60 Poly-m-phenylenethiourea
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Reactions with Thiourea
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Di - o - hydroxycyclohexylthio urea Dimethylcyclohexylthiourea Phenylethanolthiourea N (0 hydroxyethyl) N 1 - 4 allyloxyphenylthiourea N ( p - hydroxyethyl) N1 - 4 isoamyloxyphenylthiourea S Methyl ,VI 4 ethoxy phenylthiourea N Dimethyl N 1 - 4 isopro pyloxyphenylthiourea A'- Dimethyl h ' 1 - 4 ethoxy phenylthiourea N (n -Butyl) N 1 - 4 -ethoxyphenylthiourea .V (Di n butyl) .Vi - 4 ethoxyphenylthiourea S - E t h y l N 1 - 4 isobutyloxyphenylthiourea S ( p - Diethylaminoethyl) S'-n-butyloxyphenylthiourea h' - ( p chlorophenyl) - .VI acetylthiourea s-Diphenylthiourea s-Di-o-tolylthiourea
Ag+. Tan precipitate (neutral) ; black precipitate (ammoniacal) Bi+++. Bright yellow color (acid) Ce++++. Decolorized (acid) Cu++. Brown precipitate (ammoniacal) ; white precipitate (acid) Fe'+ Light pink color (acid) Hgz++, Gray precipitate (acid) IrCl6--. Decolorized (acid) Osos--. Brown color (neutral); red color (acid); gray color (ammoniacal) Pd++. Yellow color (acid and ammoniacal) PtC&,--. Brown precipitate (ammoniacal) RuC14-. Dark greenish-blue color (acid) Sb+++. Pale yellow color (acid) Se03--. Red precipitate (acid) T1+. \T7hite precipitate (neutral) ; heavy white precipitate (acid) +
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Reactions with Substituted Thioureas The following reactions are listed for each inorganic ion, the numbers referring t o the organic compounds listed above. The descriptions of colors and precipitates are probably not complete or exact in all cases, because the reactions a r e grouped as much as possible for sake of brevity. They are, however, adequate for all practical purposes.
p-Fluorophenylthiourea p-Ethoxyphenylthiourea o-Met hoxyphenylthiourea p-9Iethoxyphenylthiourea p-Isoamyloxyphenylthiourea o-n-Butyloxyphenylthiourea 2 hlethoxy - 5 - methylphenylthiourea 2,4-Dimethylphenylthiourea a-Naphthylthiourea Di-0-naphthylthiourea p-h'aphthylthiourea ac. - Tetrahydro naphthyl thiourea N - 4 Ethonyphenylpiperidylthiourea
SILVER(Ag+) Neutral Medium Tan to brown precipitates. 2, 3, 9, 11, 13 to 21, 24 to 27, 33,34,40 to 52,55 to 59 White GreciDitate. m e h i t a t e . 5. 12. 38. 39 Yellow*precipitate. SO ' ' Deep purple-brown precipitate. 53, 54
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White precipitate. 2, 3, 5 to 13, 16 t o 24, 26, 27, 29, 30, 32 to 39,41 to 49,51,55 to 59 Yellow precipitate. 60 .4mmoniacal Medium A11 brown to black precipitates except 12, 28, and 38 Khite precipitate. 38
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GOLD( A u C k ) Acid Medium Decolorized. 1 to 5 , 7 to 10, 12, 13, 16, 20 t o 24, 26 to 39, 41 to 45,47.49, 51, 55 to 57 Brown precipitate. 6, 11, 14, 15, 17, 18, 19, 25, 46, 53, 58, 60 Orange color. 40, 48, 50. 52, 54, 59 BISMUTH(Bi++') Acid AIedium Yellow color or precipitate i n 311 ea-es except 12, 15, arid 40 CEKIUM(Ce+++') Acid Medium X)ecolorized. 1 to 11, 13, 14, 17, 18, 20 to 24, 26 to 39, 41 to 47. 51. 52. 53 to 57 Tan color. 12, 19, 60 Pink color, 25, 40 Pale gray color. 48 Blue color. 49 Purple flash, blue color. 33 Yellow color changes to gray precipitate. 58 Pink color changes to gray precipitate. 59
COPPER(Cu+') Xeutral Medium White precipitate. 5 to 8 , 10, 14, 16 to 24, 26, 27, 32 to 34, 37 to 39,41,42,46,54,56, ?7, 59 Tan to brown color or precipitate. 9, 44,50, 51, 53, 60 Green color or precipitate. 12, 13, 25, 30, 40, 4.5 Unstable red color. 28, 29, 35, 36 Unstable tan color. 43,47 to 49, 55 Unstable purple color. 32 Green color, changes immediately to blue precipitate. 38 Acid Nedium Kliite precipitate. 5 to 8. 10, 16, 17, 18, 20 to 24, 26, 27, 29, 32, 33,49, 54, 56 to 59 Pink color or precipitate 3. 9, 13, 25, 43, 44, 47 I3row.n precipitate. 30. 53 Unstable red color. 11.28. 35 to 39,41, 42, 46, 48, 50, 51, 55 Ammoniacal Nedium Gray black precipitate. 20, 21 Brown-black precipitate. 9, 14. 16. 22, 23, 33, 34, 44, 52, 57 Blue color discharged. 1, 7 Brown precipitate. 2, 5 , 6 , 8, LO, :I,, 13. 15, 17, 18, 24,26,27. 35 to 43.45 to 49. 51. 34,06. ,58. 59. 60 _28. _ 31. (;ray-green precipitate. 12, 19, 25. 30, 32 Purple precipitate. 50,53, 55 IRON(Fe'-+) Acid Medium Pale yellow to tan color. 1, 4, 6, 8, 10, 11, 13, 16, 17, 27, 31, 56, 57, 58, 59 Yellolv color, changes immediately to purple. 53 MERCURY (Hg2++) Acid Medium Gray to black precipitate in nll cases except 60 Yellow precipitate. 60
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~IERCUK (Ha++) Y Keutral Medium White precipitate. 5, 9, 11. 12. 13. 16, 18, 20 to 23, 25 to 27, 33, 34,37, 39,41 to 43, 45, 46, 47,49, 51. 54, 57 Slightly gray precipitate.
