172 A-C.] 



HYDROGEN CYANIDE 



265 



on ignition give a boron nitride which, 

 on fusion with potassium carbonate and 

 carbon, yields potassium cyanide (Mo'ise, 

 Germ. Pat. 91708 of 1895 ; Ch. Centr. 

 1897, 2, 156). 



Cyanogen is formed on passing electric 

 sparks between carbon poles in an at- 

 mosphere of nitrogen (Morren, Comp. 

 Rend. 48, 342), and this combines with 

 hydrogen under the influence of the 

 silent electric discharge (Boillot, Comp. 

 Rend. 76, 1132), or on heating the 

 mixed gases to 500-550 (Berthelot, 

 Bull. Soc. [2] 33, 2 ; Ann. Chim. [5] 

 18, 380). An aqueous solution of 

 cyanogen is found to contain hydrogen 

 cyanide among other products after long 

 keeping (Wohler, Pogg. Ann. 15, 627). 



Phospham (Gerhard t, Ann. Chim. 

 [3] 18, 1 88; 20, 225; Liebig and 

 Wohler, Ann. 11, 139; Pauli, Ann. 

 101, 41 ; Salzmann, Ber. 7, 494; Besson, 

 Comp. Rend. 114, 1264), on heating 

 with an alkaline carbonate and carbon 

 or iron, gives a cyanide or ferrocyanide 

 respectively (Vidal, Germ. Pat. 95340 

 of 1897 Ch. Centr. 1898, 1, 542). 



[B.] Carbon disulplnfle [160] and 

 ammonia combine to form ammonium 

 thiocyanate (Zeise, Ann. 47, 36; Millon, 

 Jahresber. 1860, 237; Zeit. [i] 1861, 

 64 ; Gelis, Jahresber. 1861, 340 ; 1863, 

 746 ; Schwartz, Wagner's Jahresber. 

 1869, 269 ; Schulze, Journ. pr. Ch. 

 [2] 47, 518; Claus, Ann. 179, 112: 

 for combination in presence of sul- 

 phites and hydrosulphites see Goldberg 

 and Siepermann, Germ. Pats. 83435 

 of 1895, and 87813 of 1896; Ber. 28, 

 Ref. 950; 29, Ref. 744: for historical 

 summary and patented processes see 

 further N. Caro, Ch. Ind. 13, 244 ; 14, 

 287 ; Conroy, Journ. Soc. Ch. Ind. 15, 

 10 : for production of thiocyanates from 

 carbon disulphide and ammonia in pre- 

 sence of lime or magnesia see Hood and 

 Salamon, Germ. Pat. 72644 of 1892; 

 Ber. 27, Ref. 281; British Cyanides 

 Co., Germ. Pat. 81116 of 1894; Ber. 

 28, Ref. 667 ; Albright and Hood, 

 Germ. Pat. 85493 of 1895; Ber. 29, 

 Ref. 314: for technical production of 

 thiocyanates see also Tscherniac and 

 Giinzburg, Ding. poly. Journ. 245, 

 214; Journ. Soc. Ch. Ind. 1, 150; 



Nafzger, Journ. Soc. Ch. Ind. 5, 324; 

 Gasch, Ibid. 379 ; Crowther and Rossi- 

 ter, Ibid. 13, 887 ; Brock, &c., Ibid. 

 1195; Albright and Hood, Ibid. 14, 



657)-. 



Thiocyanates can by various pro- 

 cesses of oxidation or reduction be con- 

 verted into cyanides or ferrocyanides 

 (Pean, Jahresber. 1858, 585; Gelis, 

 Wagner's Jahresber. 1862, 283 ; 1863, 

 321 ; Fleck, Ibid. 1863, 323 ; Alander, 

 Ding. poly. Journ. 226, 318; Tscherniak 

 and Giinsburg, Jahresber. 1878, 1123; 

 Wagner's Jahresber. 1878, 500 ; 1879, 

 471 ; 188O, 386; 1882, 510; Playfair, 

 Eng. Pat. 7764 of 1890 ; Journ. Soc. 

 Ch. Ind. 11, 14; Liittke, Germ. Pat. 

 89607 of 1895; Ber. 29, Ref. 1197; 

 United Alkali Co., Germ. Pat. 97896 

 of 1895; Ch. Centr. 1898, 2, 837: 

 for electrolytic oxidation see Parker, 

 Eng. Pats. 17447 of 1888 and 2383 

 of 1889 and also Journ. Soc. Ch. 

 Ind. 9, 67 ; 291 : for oxidation by hy- 

 drogen peroxide see Raudnitz, Zeit. 

 BioL, Jubelband, 42, 91 ; Ch. Centr. 



1901, 2, 1234: for historical summary 

 from the technological point of view see 

 Caro and Conroy as above ; also for 

 Raschen's process of oxidation by nitric 

 acid, Conroy, Journ. Soc. Ch. Ind. 18, 

 432 : see further Raschen, &c., Journ. 

 Soc. Ch. Ind. 14, 1046 ; Goerlich and 

 Wichmann, Ibid. 657 ; Beringer, Eng. 

 Pat. 18565 of 1899 ; Raschen, Norman, 

 and Luxton and the United Alkali Co., 

 Eng. Pat. 12180 of 1900; Journ. Soc. 

 Ch. Ind. 20, 809 : for reduction of thio- 

 cyanates to cyanides by hydrogen see 

 Sestini and Funaro, Gazz. 12, 184; 

 Conroy, Heslop, and Shores, Journ. Soc. 

 Ch. Ind. 20, 320; British Cyanides Co., 

 Germ. Pat. 132294 of 1901 ; Ch. Centr. 



1902, 2, 80 : for reduction of copper 

 and other thiocyanates see Rossiter, 

 Crowther, and Albright, Eng. Pats. 

 4403 and 6226 of 1901 ; Journ. Soc. 

 Ch. Ind. 21, 173; 345). 



Cyanides are formed also from thio- 

 cyanates by heating the latter with 

 calcium carbide or in an atmosphere of 

 acetylene (Conroy, Heslop, and Shores, 

 loo. cit. ; Sandmann, Zeit. angew. Ch. 



15, 543)- 



[C.] From benzene [6 ; I, &c.J, the 



