106 



POLYHYDRIC ALCOHOLS 



[51 A-52. 



latter by fractional crystallisation of 

 the morphine or strychnine salt is re- 

 solved into d- and 1-mannonic acids. 

 The d-acid on reduction with sodium 

 amalgam in acid solution gives d-man- 

 nose [156], and by further reduction of 

 the latter with sodium amalgam in 

 alkaline solution d-mannitol (Fischer 

 and Hirschberger, Ber. 21, 1 808 : see 

 also Ber. 23, 2133). 



[B.] Glycerol [48] when heated with 

 dehydrating agents, such as acid potas- 

 sium sulphate, yields acrole'in [lOl] 

 (Redtenbacher, Ann. 47, 120; Aronstein, 

 Ann. Supp. 3, 1 80 ; Van Romburgh, Bull. 

 Soc. [2] 36, 550 ; Griner, Ann. Chim. 

 [6] 26, 367 ; Wohl and Neuberg, Ber. 

 32, 1352), which combines with bromine 

 to form acrolein bromide = 2 : 3-di- 

 brompropionic aldehyde (Aronstein, loc. 

 cit. 185; Henry, Ber. 7, ni2; Linne- 

 mann and Penl, Ber. 8, 1097). The 

 latter on treatment with baryta water 

 gives a product from which the osazone 

 of a-acrose can be isolated (Fischer and 

 Tafel, Ber. 20, 1092; 2566) and con- 

 verted into mannitol as under A. 



Glycerol can also be directly oxidised 

 by means of bromine in presence of 

 sodium carbonate solution (Fischer and 

 Tafel, Ber. 20, 3385), the 'glycerose' 

 thus obtained giving rise by the action 

 of alkali to a mixture of sugars from 

 which a-acrose can be isolated and 

 treated as above. 



NOTE : According to Neuberg (Ber. 35, 2632) 

 acrose partly consists of d-fructose. Glycerose 

 is a mixture of dihydroxyacetone and glyceric 

 aldehyde, the former predominating (see under 

 dihydroxyacetone [151 ; D]). 



[C.] Acetone [106] gives a dibromide 

 (C 3 H 6 O . Br 2 ) by the action of bromine, 

 this compound on distillation giving 

 acrolein (Linnemann, Ann. 125, 310), 

 which can be converted into a-acrose, 

 &c., as under B. 



[D.] From dextrose [154] by reduc- 

 tion with sodium amalgam (Dewar, 

 Phil. Mag. 4, 39 ; Adrian Brown, 

 Trans. Ch. Soc. 51, 642; Bouchardat, 

 Bull. Soc. [2] 16, 38). The yield is 

 small. 



[E.] From lavulose [155] by reduc- 

 tion with sodium amalgam (Krusemann, 

 Ber. 9, 1465; Fischer, Ber. 23, 3684). 



The yield is 30-40 per cent, of the 

 Isevulose, about 50 per cent, of sorbitol 

 being formed simultaneously. 



[F.] From mannose [156] through 

 Isevulose (see under sorbitol [52; C]), 

 and then as above under E. 



[G-.] From tartaric acid [Vol. II] 

 through dihydroxymalei'c acid by oxida- 

 tion with hydrogen peroxide in presence 

 of ferrous salts. The acid referred to 

 decomposes in aqueous solution with 

 the formation of glycollic aldehyde, and 

 the latter, on heating in vacua at 100, 

 polymerises to a mixture of a- and /3- 

 acrose (Fenton, Trans. Ch. Soc. 65, 

 899; 67,48; 774; 68,546; 71,375; 

 Jackson, I&id. 77, 129)- The polymeri- 

 sation of the aldehyde takes place in 

 presence of dilute caustic soda at o 

 (Jackson, loc. cit.). 



[H.] From acetal [93] through gly- 

 collic aldehyde (see under furfural [126 ; 

 P]), and then as above. 



[I.] From ethyl alcohol [14] through 

 glycollic aldehyde . (see under furfural 

 [126 ; G]), and then as above. 



[J.] From choline [Vol. II] through 

 glycollic aldehyde (see under furfural 

 [126 ; H]), and then as above. 



[K.] Gluconic acid [Vol. II] has been 

 said to give mannitol on reduction with 

 sodium amalgam in acid solution (v. 

 Wachtel ; Tollens, ' Kohlenhydrate/ II, 

 282; Fischer, Ber. 23, 930: see also 

 Herzfeld, Ann. 220, 335). 



52. Sorbitol ; Hexaiiehexol. 

 HOH HO HO 



HO . H 2 C-C- C-C-C-CH 2 . OH 



I I I I 

 H HOH H 



(Dextro-modification). 



NATURAL SOURCES. 



In berries of mountain-ash (Boussin- 

 gault, Ann. Chim. [4] 26, 376 ; Hitze- 

 mann and Tollens, Ber. 22, 1048) ; in 

 apples, pears, medlars, plums, and 

 cherries (Vincent and Delachanal, 

 Comp. Rend. 108, 354; 109, 676; 

 114, 486; Bull. Soc. [a] 34, 218), and 

 in beet-sugar molasses (v. Lippmann, 

 Ber. 25, 3216). 



