144 C.] 



METAHYDROXYANTHRAQUINONE 



237 



with phosphorus pentoxide (Paternb and 

 Fileti, loc. cit. 3, 252). 



p-Benzylphenol can also be obtained 

 from phenol and benzole aldehyde [114]. 

 The latter on treatment with potassium 

 cyanide forms benzoin (Liebig and 

 Wohler, Ann. 3, 276 ; Zinin, Ann. 34, 

 186 ; Zincke, Ann. 198, 151). A mix- 

 ture of benzoin and phenol gives p- 

 desylphenol on treatment with strong 

 sulphuric acid (Japp and Wadsworth, 

 Trans. Ch. Soc. 57, 965), and this on 

 fusion with potash yields p-benzylphenol 

 (Ibid. 972). 



Or benzole acid [Vol. II] and toluene, 

 when heated to 200 with phosphorus 

 pentoxide, give phenyl-o-toluyl ketone 

 (Kollarits and Merz, Ber. 6, 538 : the 

 p-modification is simultaneously formed). 

 The latter yields anthracene on heating 

 with zinc dust (Behr and Van Dorp, 

 Ber. 7, 17). 



NOTE : Phenyl-o-toluyl ketone is among the 

 products of the oxidation of toluene by man- 

 ganese dioxide and sulphuric acid (Weiler, 

 Ber. 33, 464). 



Anthracene is formed by passing the 

 vapours of many synthetical hydro- 

 carbons through red-hot tubes : Thus, 

 from ethylene and benzene, benzene and 

 styrene, o-benzyltoluene, &c. (Berthelot, 

 Bull. Soc. [2] 7, 223; 8, 231 ; 9, 295 ; 

 Ann. 142, 254 ; Van Dorp, Ann. 169, 

 2 1 6 : for pyrogenic syntheses of anthra- 

 cene from benzene and ethylene, from 

 toluene vapour, and from ethylbenzene, 

 see Ferko, Ber. 2O, 660). 



Anthracene is among the hydro- 

 carbons formed by passing through a 

 hot tube ethylene (Norton and Noyes, 

 Am. Ch. Journ. 8. 362), ethylene and di- 

 phenyl (Barbier, Comp. Rend. 79, 121), 

 heptane and octane at 900 (Worstall 

 and Bur well, Am. Ch. Journ. 19, 815). 



Anthracene is among the products 

 formed by the action of dry aluminium 

 chloride on acetylene (Baud, Comp. 

 Rend. 130, 1319), and by the action at 

 600-800 of certain metallic carbides, 

 e. g. barium, on the corresponding hy- 

 droxides (Bradley and Jacobs, Germ. 

 Pat. 125936 of 1898; Ch. Centr. 1902, 



1, 77)- 



Styrene on combination with bromine 



gives i 1 : i 2 -dibromethylbenzene (Blyth 

 and Hofmann, Ann. 53, 306 ; Glaser, 

 Ann. 154, 154; Zincke, Ann. 216, 288). 

 The same dibromethylbenzene can be 

 obtained by the bromination of ethyl- 

 benzene (Radziszewski, Ber. 6, 493 ; 

 Friedel and Balsohn, Bull. Soc. [2] 35, 

 55). i 1 : i 2 -Dibromethylbenzene gives 

 anthracene by the action of aluminium 

 chloride on its benzene solution 

 (Schramm, Beilstein's ' Handbuch/ ^rd 

 ed. II, 257). 



Syntheses of Anthraquinone. 



From phthalic anhydride (see under 

 benzyl alcohol [54; B,]) and benzene, 

 a mixture (solution) of these giving, 

 when treated with aluminium chloride, 

 o-benzoylbenzoic acid (Friedel and 

 Crafts, Ann. Chim. [6] 14, 446 ; Comp. 

 Rend. 86, 1368). The latter, on heat- 

 ing per se or with phosphorus pentoxide 

 or strong sulphuric acid, yields anthra- 

 quinone (Ullmann, Ann. 291, 24 ; Behr 

 and Van Dorp, Ber. 7, 578; Liebermann, 

 Ibid. 805 ; W. H. Perkin, junr., Trans. 

 Ch. Soc. 59, 1012). 



NOTE : o-Benzoylbenzoic acid is among the 

 products of oxidation of toluene by potassium 

 permanganate (Weiler, Ber. 33, 465). 



Calcium phthalate gives anthraquin- 

 one on dry distillation (Panaotovits, Ber. 

 17, 313). Or phthalic acid can be con- 

 verted into phthaloyl chloride (Miiller, 

 Jahresber. 1863, 393). The latter yields 

 anthraquinone when heated with zinc 

 dust and benzene at 220, or when 

 treated with aluminium chloride in 

 benzene solution (Piccard, Ber. 7, 1785 ; 

 Friedel and Crafts, Ann. Chim. [6] 

 1, 523 ; Bull. Soc. [2] 29, 49). 



Anthraquinone is among the products 

 of the distillation of calcium benzoate 

 [Vol. II], and is formed in small 

 quantity by distilling benzoic acid with 

 phosphorus pentoxide (Kekule and 

 Franchimont, Ber. 5, 908). 



Phenyl-o-toluyl ketone (see above) 

 gives anthraquinone on heating with lead 

 oxide, or on oxidation with manganese 

 dioxide and sulphuric acid (Behr and 

 Van Dorp, Ber. 6, 754; 7, 16) ; also by 

 chlorination at 110, and decomposition 



