34 



HYDROCARBONS 



[7 A-C. 



ner, Ann. Suppl. 1, 109; Semenoff, 

 Jahresber. 1864, 480). Vinyl bromide 

 and benzene condense in the presence 

 of aluminium chloride to form styrene 

 (Hauriot and Gilbert, Jahresber. 1884, 

 561 : see also Anschiitz, Ann. 235, 

 33 1 )- 



NOTE : Vinyl bromide is formed also by the 

 combination of acetylene with hydrogen brom- 

 ide (Reboul, Comp. Rend. 74, 947). 



Or from ethyl alcohol [14] and benzene 

 through ethylbenzene by the condensa- 

 tion of ethyl bromide or iodide with ben- 

 zene in presence of aluminhim chloride 

 (Friedel and Crafts, Ann. Chim. [6] 1, 

 457). Ethylbenzene gives styrene when 

 the vapour is passed through a hot tube 

 (Berthelot, Zeit. [2] 4, 589; Ferko, 

 Ber. 20, 663). 



Or ethylbenzene on bromination at 

 its boiling-point or in presence of light 

 gives i 1 - bromethylbenzene, C 6 H 5 . 

 CHBr . CH 3 (Berthelot, Bull. Soc. 1O, 

 343; Comp. Rend. 67, 328; Radzis- 

 zewski, Ber. 6, 492 ; 7, 141 ; Anschiitz, 

 Ann. 235, 328 ; Schramm, Ber. 18, 351), 

 and this gives styrene by the action of 

 heat or of alcoholic potash (Thorpe, 

 Proc. Roy. Soc. 18, 123 ; Radziszewski, 

 Ber. 7, 140). Or ethylbenzene on 

 bromination with two molecules of 

 bromine gives I 1 : i 2 -dibromethylben- 

 zene = styrene bromide (Radziszewski, 

 Ber. 6, 493 > a ^ so Friedel and Balsohn, 

 Bull. Soc. [2] 35, 55), and this on 

 heating with strong alcoholic potash at 

 1 20 gives phenylacetylene (Glaser, Ann. 

 154, 155 ; Zeit. [2] 5, 97 ; Friedel and 

 Balsohn, loc. cit.; Holleman, Ber. 20, 

 3080; see also Moureu and Delange, 

 Bull. Soc. [3] 25, 302). The latter 

 can be reduced to styrene by zinc and 

 acetic acid (Aronstein and Holleman, 

 Ber. 22, 1184). 



Or ethylbenzene can be converted 

 into phenylacetaldehyde = a-toluic alde- 

 hyde and co-phenylethylamine (see under 

 phenylethyl mustard oil [170 ; A]). 

 The hydrochloride of the latter gives 

 styrene on distillation (Fileti and Piccini, 

 Ber. 12, 1308). 



NOTE : Generators of ethylbenzene are given 

 under phlorol as follows : Tartaric or racemic 

 acid [Vol. II] and n-propyl alcohol [15] through 

 ethylisophthalic acid (see under phlorol [64 ; 



J]). Bemoic and acetic acids [Vol. II] through 

 acetophenone (see belowunder D) and dypnone 

 (see under phlorol [64 ; K]). Full references 

 to syntheses of ethylbenzene from benzene are 

 given under phlorol [64 ; A]. 



Benzene can be converted into aceto- 

 phenone by various processes (see under 

 benzoic aldehyde [114; A]). Theketone 

 reduces to methylphenyl carbinol [58] 

 (Emmerling and Engler, Ber. 6, 1006 ; 

 Klages and Allendorff, Ber. 31, 1003), 

 and this gives styrene on heating with 

 zinc chloride or by distilling the acetate 

 (E. and E. Ber. 4, 147 ; Radziszewski, 

 Ber. 7, 140), or by heating with syrupy 

 phosphoric acid (Klages and Allendorff, 

 Ber. 31, 1298). 



Or methylethyl carbinol by the action 

 of hydrobromic acid gives i ^brom- 

 ethylbenzene (Engler and Bethge, Ber. 

 7, 1 126), which gives styrene as above. 



Or acetophenone and hydrogen sul- 

 phide combine in presence of hydrogen 

 chloride to form a trithio-derivative 

 (C 24 H 24 S 3 ) which gives styrene on 

 heating (Baumann and Fromm, Ber. 28, 

 901). 



By the action of phosphorus penta- 

 chloride acetophenone is converted into 

 the dichloride = I 1 : I 1 -dichlorethyl- 

 benzene, and this gives phenylacetylene 

 by the action of alcoholic potash or hot 

 lime (Friedel, Comp. Rend. 67, 1192; 

 Morgan, Journ. Ch. Soc. 29, 164; 

 Peratoner, Gazz. 22, 67 ; Nef, Ch. 

 Centr. 1899, 2, 933). Phenylacetylene 

 can be reduced to styrene as above. 



Toluene gives benzyl chloride on 

 chlorination at its boiling-point (see 

 under benzyl alcohol [54 ; A]), and this 

 by interaction with potassium cyanide 

 [172] and reduction of the product gives 

 phenylethylamine (see under phenyl- 

 ethyl mustard oil [17O; A]), which gives 

 styrene as above under A. 



[B.] Cymene \Q\ gives cumic aldehyde 

 and acid, and isopropylbenzene(see under 

 benzoic aldehyde [114 ; K]). The latter 

 gives acetophenone among the products 

 of the action of chromium oxychloride 

 (Miller and Rohde, Ber. 24, 1358). 

 Acetophenone gives styrene as above 

 under A. 



[C.] From benzoic aldehyde [114] and 

 acetic acid [Vol. II] and alcohol [14] 

 through phenylglycidic acid, a-toluic 



