114 -A.] 



BENZOIC ALDEHYDE 



205 



AROMATIC ALDEHYDES AND KETONES. 



114. Benzole Aldehyde ; 

 Benzaldehyde ; Fhenal. 



CHO 



NATURAL SOURCES. 



The complex exists in the glucoside 

 amygdalin, first discovered in the bitter 

 almond, Amygdalus communis, var. amara 

 (Robiquet and Boudron, Ann. Chim. 

 [2] 44, 352 ; Henry and Boudron, 

 Journ. Pharm. 22, 1 1 8). 



Amygdalin, either alone or in associa- 

 tion with its amorphous form, lauro- 

 cerasin, exists also in seeds of Prunus 

 domestica, P. spinosa, P. armenica, 

 P. avium, P. cerasus, P. cerasus-aus- 

 tera, P. chameecerasus, P. laurocerasus, 

 P. padus, P. mahaleb, Persica vulgaris, 

 Amygdalus nana, Pyrus malus, Cyclonia 

 vulgaris, Sorbus aueuparia, Cotoneaster 

 vulgaris, Cratcegus oxyacantka, Metpiht* 

 japonica (Van Rijn, ' Die Glykoside/ 

 p. 232). 



Amygdalin occurs also in leaves of 

 Gymnema latifollum, and in the bark 

 of species of Pygium (Greshoff, Ber. 23, 

 3548). 



NOTE : For full references see Van Rijn as 

 above ; for occurrence of amygdalin in Dru- 

 paceous and Pomaceous plants see Lehmann, 

 Jahresber. 1885, 1799; for recent confirmation 

 of occurrence in seeds of Pomaceae, viz. Malus 

 communis, Cydonia vulgaris. C. japonica, Sorbus 

 aria, and S. aueuparia, see Lutz, Rep. d. Pharm. 

 1897, 312. 



Benzaldehyde occurs in niauli oil 

 from the fresh leaves of Melaleuca 

 viridiflora, New Caledonia (Bertrand, 

 Bull. Soc. [3] 9, 433) ; in cajeput oil 

 from the leaves and stems of Melaleuca 

 leucadendron (Voiry, Comp. Rend. 1O6, 

 1538; Bull. Soc. [2] 50, 108); in oil 

 of cinnamon from Cinnamomum zeylani- 

 cum (Weber, Arch. Pharm. 230, 728 : 

 for occurrence in oil of Ceylon cinnamon 



see SchimmeFs Ber. April, 1902 ; Wal- 

 baum and Hiithig, Journ. pr. Ch. [2] 



66, 47)- 



The aldehyde occurs in oil from the 

 leaves of Indigofem galegoules (Schim- 

 meFs Ber. Oct. 1894, and April, 1896). 



Oroxylin from the bark of Oroxylon 

 indicum may contain the benzoic alde- 

 hyde complex (Naylor and Dyer, Trans. 

 Ch. Soc. 79, 954). The aldehyde is 

 contained in rassamala resin from the 

 Javan Attingia excelsa (Tschirch and 

 Van Itallie, Arch. Pharm. 239, 541). 



A condensation product of benzalde- 

 hyde and methyl-n-nonyl ketone occurs 

 in oil of rue (Thorns ; SchimmeFs Ber. 

 Oct. 1901). 



SYNTHETICAL PROCESSES. 



[A.] All generators of benzene and 

 toluene (see under cymene [6] and under 

 benzyl alcohol [54]) become generators 

 of benzoic aldehyde through the follow- 

 ing processes : 



Benzyl chloride by oxidation with 

 dilute nitric acid or lead nitrate (Ber- 

 tagnini, Ann. 85, 183; Lauth and 

 Grimaux, Bull. Soc. [2] 7, 106). 



Or toluene can be chlorinated up to 

 the stage of benzylidene = benzal 

 chloride (Beilstein, Ann. 116, 336; 

 146, 322; Schramm, Ber. 18, 608). 

 The latter gives benzoic aldehyde on 

 heating with water, alkalis, or alkaline 

 carbonates in aqueous solution (Cahours, 

 Comp. Rend. 56, 222; Meunier, Bull. 

 Soc. [2] 38, 159 ; Limpricht, Ann. 

 139, 319), or with milk of lime (techni- 

 cal process : Espenschied, Germ. Pat. 

 47187 of 1880), or with water at 95 

 in presence of iron or iron salts 

 (Schultze, Germ. Pats. 82927 of 1894 

 and 85493 of 1895 ; Ber. 28, Ref. 879 ; 

 29, Ref. 314). Benzal bromide yields 

 the aldehyde on contact with water 

 at ordinary temperatures (Curtius and 

 Quedenfeldt, Journ. pr. Ch. [2] 58, 

 390). 



A mixture of benzyl and benzal 

 chlorides gives benzaldehyde on oxida- 



