54 K-M.] 



BENZYL ALCOHOL 



113 



treated with alcoholic potash or barium 

 hydroxide solution (Hell and Lauber, 

 Ber. 7, 560 ; Michael and Graves, Ber. 

 34, 4041 : compare also Duvillier, 

 Ann. Chim. [5] 17, 532 ; Michael, 

 Journ. pr. Ch. [2] 35, 92; 38, 12; 

 Erlenmeyer and Marx as quoted by 

 Michael and Graves, loo. cit. 4040). 

 The sodium salt of a-brombutyric acid 

 also gives crotonic acid on distillation 

 (Bischoff and Walden, Ann. 279, 101). 



Butyryl chloride on chlorination also 

 gives a- (with /3 and y) chlorbutyryl 

 chloride. The corresponding a-chloro- 

 acid gives crotonic acid (with a-hydroxy- 

 butyric acid) on treatment with barium 

 hydroxide solution (Michael and Garner, 

 Ber. 34, 4051). 



[L.] p-Hydroxybutyric acid [Vol. II] 

 gives crotonic acid on distillation (Wis- 

 licenus, Zeit. [2] 5, 325 ; Araki, Zeit. 

 physik. Ch. 18, i). Or the acid (sodium 

 salt) gives crotonic aldehyde [1O2] on 

 electrolysis (v. Miller and Hot'er, Ber. 



27, 468). From the aldehyde through 

 crotonic acid, &c., as under H. 



[M.] Citric acid [Vol. II] gives 

 citraconic anhydride on distillation 

 (Lassaigne, Ann. Chim. [2] 21, 100 ; 

 Robiquet, Ibid. 75, 78; Liebig, Ann. 

 26,119; 152; Gottlieb, Ann. 77, 265 ; 

 Baup, Ann. Chim. [3] 33, 192; Wilm, 

 Ann. 141, 28 ; Kammerer, Ann. 17O, 

 191), which combines readily with 

 water to form citraconic acid. The 

 latter is also obtained by heating citric 

 acid with hydriodic acid (Kammerer, 

 Ann. 139, 269). Potassium citraconate 

 gives on electrolysis in aqueous solution 

 allylene (Aarland, Journ. pr. Ch. [2] 7, 

 1 42) among other products, and this can 

 be converted into mesitylene, &c., as 

 under E. 



Or the citraconic anhydride can be 

 converted into citrabrompyrotartaric 

 acid by the action of hydrogen bromide 

 (Fittig, Ann. 188, 77), the silver salt of 

 the acid giving allylene on heating with 

 water at 130 (Bourgoin, Bull. Soc. [2] 



28, 459). 



Mesaconic acid, the isomeride of citra- 

 conic acid produced from the latter by 

 heating with aqueous acids or alkalis or 

 by the action of bromine (Gottlieb, Ann. 

 77, 268 ; Kekule, Ann. Suppl. 2, 94 ; 



Fittig, Ann. 188, 77 ; 80 ; Delisle, Ann. 

 269, 82 ; Swarts, Jahresber. 1873, 579 ; 

 Fittig and Langworthy, Ann. 304, 145), 

 also gives allylene on electrolysis of a 

 solution of the potassium salt (Aarland, 

 Journ. pr. Ch. [2] 7, 143). 



Citraconic acid also by boiling with 

 alkali gives (with mesaconic acid) ita- 

 conic acid. The three isomerides, citra- 

 conic, mesaconic, and itaconic acids, all 

 give pyrotartaric acid on reduction by 

 sodium amalgam, preferably in acid 

 solution (Kekule, Ann. Suppl. 1, 338 ; 

 Suppl. 2, 95 : also Fittig and Lang- 

 worthy, loc. cit.}. The latter can be 

 treated as underN. Citraconic and mesa- 

 conic acids give pyroracemic (pyruvic) 

 acid on oxidation (Fittig and Kohl, Ann. 

 3O5, 41). The latter can be converted 

 into uvitic acid, &c., as under I above. 

 Conversely pyroracemic and malonic 

 acid combine when heated in acetic 

 acid solution to form itaconic acid and 

 some citraconic acid (Garzarolli-Thurn- 

 lach, Monats. 20, 467). 



NOTE : Other synthetical products which 

 are generators of citraconic acid are : Lactic 

 acid [Vol. II] by distillation (Engelhardt, Ann. 

 70, 243 ; 246). 



Acetic acid [Vol. II], alcohol [14], and hydrogen 

 cyanide [172], by the action of the latter on aceto- 

 acetic ester (Morris, Journ. Ch. Soc. 37, 7 ; De- 

 mai'9ay, Bull. Soc. [2] 27, 120), hydroxypyro- 

 tartaric acid by boiling the product with dilute 

 hydrochloric acid and dry distillation of the 

 former, which thus gives citraconic anhydride 

 (Demar9ay, Comp. Rend. 82, 1337 ; Ber. 9,962). 



Isovaleric acid [Vol. II], which by oxidation 

 with nitric acid gives hydroxy pyrotartaric acid 

 (Bredt, Ber. 14, 1782 ; 15, 2318) and citraconic 

 anhydride as before. [The hydroxypyrotar- 

 taric acid formed is the j8-acid = citramalic = 

 2-methyl-2-butanoldiacid ; for preparation from 

 acetoacetic ester and potassium cyanide see also 

 Michael, Journ. pr. Ch. [2] 46, 287.] 



Propionic and malonic acids [Vol. II] by the 

 action of a-brompropionic ester (Friedel and 

 Machuca, Ann. 120, 286) on sodio-malonic 

 ester, which gives propanetricarboxylie tri- 

 ethyl (0-methylethenyltricarboxylic) ester (Bi- 

 schoff, Ann. 214, 53), the chloro-derivative of 

 the latter (Ibid. Ber. 23, 1934) giving citra- 

 conic (and mesaconic) acid on heating with 

 hydrochloric acid (Ibid.). [This propanetricar- 

 boxylie acid obtained from the ester by hydro- 

 lysis gives pyrotartaric acid on heating with 

 hydrochloric acid or per se.] 



Acetic and propionic acids [Vol. II], alcohol [14], 

 and potassium cyanide [172] through a-methyl- 

 /3-cyanosuccinic ester by the action of a-brom- 

 propionic ester on sodio-cyanacetic ester 

 (Barthe, Ann. Chim. [6] 27, 277), and decompo- 

 sition with alcoholic hydrogen chloride (Ibid. 

 281). 



