166 FUMARIC ACID. 



iodide ; from sulphosuccinic acid by fusing with potassa ; 

 most readily from malic acid, which when heated to 150 

 is resolved almost completely into f umaric acid and water. 

 Properties. Colorless prisms, difficultly soluble in 

 cold water, more easily in hot water. Fuses and vola- 

 tilizes above 200, partially without decomposition, 

 for the greater part, however, being resolved into water 

 and maleic anhydride. It is converted into succinic 

 acid by nascent hydrogen, and when heated with 

 hydriodic acid ; combines directly with bromine, form- 

 ing dibromsuccinic acid. 



Barium fumarate, C 4 H 2 4 Ba, and Calcium fu- 

 marate, C 4 H 2 OCa,are difficultly soluble crystalline pre- 

 cipitates. Silver fumarate, C 4 H 2 4 Ag 2 . White amor- 

 phous, insoluble precipitate. Detonates when heated. 



Ethyl fumarate, C 4 H 2 4 .(C 2 H 5 ) 2 , is produced by dis- 

 tilling ethyl malate either alone or with phosphorus 

 chloride. Colorless liquid, boiling at 225. 



Maleic acid, C 4 H 4 4 = C 2 H 2 (CO.OH) 2 , (isomeric 

 with fumaric acid). The anhydride of this acid (C 4 H 2 3 , 

 fusing point, 57 ; boiling point, 196), is produced by 

 heating fumaric acid and by distilling malic acid rapidly. 

 This is readily converted into the acid by assimila- 

 tion of water. Colorless prisms, very easily soluble in 

 water and alcohol. Fusing point, 130. At 160 it is 

 resolved into its anhydride and water. When boiled 

 with dilute sulphuric acid or treated with hydrobromic 

 acid or hydriodic acid, it is converted into fumaric 

 acid. It combines with hydrogen, forming succinic 

 acid ; with bromine forming isodibromsuccinic acid. 



Chlprmaleic acid, C 2 HC1(CO.OH) 2 . When 1 part 

 tartaric acid is heated with 6 parts phosphorus chloride, 

 there is formed chlormaleinchloride C 2 HC1(CO.C1) 2 , an 

 oily substance. This is decomposed by water, forming 

 hydrochloric acid and chlormalei'c acid. Colorless, 

 small needles, soluble in water and alcohol. Fusing 

 point, 171-172. Its ether C 2 HC1(CO.O.C 2 H 6 ) 2 , a thick 



