120 



AROMATIC ALCOHOLS AND PHENOLS [eo A-C. 



SYNTHETICAL PEOCESSES. 



[A.] From acetylene (see tinder me- 

 thane [l ; A]), the sulphonic acid formed 

 by absorbing- the latter in fuming- sul- 

 phuric acid, and fusion of the sulphonic 

 acid salt with potash (Berthelot, Comp. 

 Rend. 68, 539 : could not be confirmed 

 by Schroeter, Ber. 31, 2189 ; Ann. 303, 

 132). According to later experiments 

 by Berthelot (Comp. Rend. 127, 908; 

 128, 335), the ' potassium-acetylene 

 sulphonate'' is heated to 180-200 in 

 an atmosphere of hydrogen, and then 

 distilled with dilute sulphuric acid, when 

 phenol passes over. A further quantity 

 is obtained from the residue by fusion 

 with potash at 250 (see also Ann. 

 Chim. [4] 19, 432 and [7] 17, 289.) 



Or from acetylene through benzene 

 (see under cymene [6j A]), benzene- 

 sulphonic acid (Mitscherlich, Pogg. Ann. 

 31, 283; 634; Stenhouse, Proc. Roy. 

 Soc. 14, 351 ; Wurtz, Comp. Rend. 64, 

 749 ; Michael and Adair, Ber. 1O, 585), 

 and fusion of the potassium salt with 

 excess of potash (Wurtz, Ann. 144, 121 ; 

 Bull. Soc. [2] 8, 197 ; Kekule, Lehrb. 

 d. org. Ch. 3, 13; Dusart, Zeit. [2] 3, 

 299). Benzene is said to be oxidised 

 by atmospheric air in the presence of 

 alkali with the formation of phenol 

 (Nencki, Ber. 14, 1144). 



Also from benzene by passing- air 

 through the boiling- hydrocarbon in 

 presence of aluminium chloride (Friedel 

 and Crafts, Ann. Chim. [6] 14, 435 ; 

 Bull. Soc. [2] 31, 463); by the action 

 of palladium hydride, water, and air 

 (Hoppe-Seyler, Ber. 12, 1552); or by 

 oxidation with hydrogen peroxide or 

 nascent ozone (Leeds, Ber. 14, 976; 

 Cross, Bevan, and Heiberg, Trans. Ch. 

 Soc. 75, 751). 



Also from benzene through nitro- 

 benzene, aniline, and action of nitrous 

 acid(diazo-reaction) on latter (Hofmann, 

 Ann. 75, 356; Hunt, Silliman's Am. 

 Journ. [2] 8, 372; Jahresber. 1849, 

 391 ; Griess, Ann. 137, 39 : for direct 

 production of aniline from benzene by 

 the action of hydroxylamine in presence 

 of aluminium chloride see Graebe, Ber. 

 34, 1778; Jaubert, Comp. Rend. 132, 

 841). 



A synthesis of phenol from carbon 

 is possible through mellitic (benzene- 

 hexacarboxylic) acid, which is obtained 

 by oxidising charcoal with alkaline 

 permanganate (Schulze, Ber. 4, 802 ; 

 806), by the electrolysis of dilute acid 

 or alkali with retort carbon for the 

 positive electrode (Bartoli and Papa- 

 sogli, Gazz. 11, 468 ; Ch. Centr. 1881, 

 327), by the oxidation of animal char- 

 coal or lampblack with alkaline hypo- 

 chlorite (Ibid. Gazz. 15, 446), or by 

 heating- wood charcoal with strong 

 sulphuric acid (Verneuil, Bull. Soc. [3] 

 11, 121). 



Mellitic acid is converted by dry dis- 

 tillation into pyromellitic (i : 2 : 4 : 5- 

 benzenetetracarboxylic) acid (Erdmann, 

 Ann. 80, 281), which by reduction in 

 alkaline solution with sodium amalgam 

 is converted into hydropyromellitic acid 

 (Baeyer, Ann. Suppl. 7, 38 ; 166, 337 ; 

 258, 205). The latter on heating with 

 strong sulphuric acid gives isophthalic 

 acid (Ibid. Ann. Suppl. 7, 4), which can 

 be converted into 5-sulpho- and 5-hy- 

 droxyisophthalic acid by sulphona- 

 tion and potash fusion (Heine, Ber. 

 13, 493). The latter acid gives phenol 

 on distillation with lime (see also 

 under L). 



Mellitic acid can be obtained also by 

 the oxidation of charcoal with fuming 

 nitric acid (Dickson and Eastern" eld, Proc. 

 Ch. Soc. 14, 163). 



Phenylsulphuric acid (potassium salt) 

 is obtained by the action of potassium 

 pyrosulphate on phenol in potassium 

 hydroxide solution (Baumann, Ber. 9, 

 54 and 1715; 11, 1907; Brieger, Zeit. 

 physiol. Ch. 8, 311; Drechsel, Journ. 

 pr. Ch. [2] 29, 234). The acid is also 

 among the products of the electrolysis 

 of phenol by an alternating current in 

 the presence of magnesium sulphate and 

 acid magnesium carbonate (Drechsel, 

 loc. cit.}. 



[B.] Glycerol [48] is said to give 

 phenol when distilled with calcium 

 chloride (Linnemann and Zotta, Ann. 

 174, 87 ; Suppl. 8, 254). 



[C.] From salicylic acid [Vol. II] by 

 distillation with lime (Gerhardt, Rev. 

 Scien. 10, 210; Rosenthal, Zeit. [2] 

 5, 627) ; also by heating per se, or with 



