CKOTONIC ALDEHYDE. 129 



Acrolein chloride, C 3 H 4 C1 2 = CH 2 :CH.CHC1 2 . Is 



produced, together with the isomeric dichlorglycide, 

 (see Glycerin), by the action of phosphorus pentaehlo- 

 ride on acrolein or metacrolein. Colorless liquid, boil- 

 ing at 84. 



Acrolein-ammonia, C 6 H 9 NO. Is produced when 

 the vapor of acrolein is conducted into ammonia, and 

 when an alcoholic solution of acrolein is mixed with 

 alcoholic ammonia. Yellowish-white mass, which, 

 when dried, becomes brownish-red. Combines with 

 acids, forming amorphous salts. When subjected to 

 dry distillation it is resolved into water and picoline. 



2. Crotonic Aldehyde. 

 C 4 II 6 = CH 2 :CH.CH 2 .CHO. 



Formation. Is produced from acetic aldehyde (p. 

 103), when this is heated for some time at 100 with 

 watery solutions of potassium formate or acetate, or 

 with a little zinc chloride. 



Properties. Colorless liquid, of an exceedingly pun- 

 gent odor. Boiling point, 103-105. In contact with 

 the air, and under the influence of oxidizing agents, it 

 is converted into crotonic acid. Phosphorus chloride 

 converts it into a fluid chloride C 4 H 6 C1 2 , boiling at 

 125-126. It combines with hydrochloric acid directly, 

 forming chlorbutyric aldehyde (p. 107). 



Trichlorcrotonic aldehyde (Crotonchloral), 

 C 4 H 3 C1 3 0. Is formed when acetic aldehyde, either 

 alone or dissolved in carbon tetrachloride, is saturated 

 with chlorine. Colorless, oily liquid ; boiling point, 

 163-165. Combines with water, forming a hydrate 

 C 4 H 3 C1 3 + H 2 0, which crystallizes in colorless, very 

 thin laminse, fusing at 78. Caustic potassa decom- 

 poses it without the aid of heat, forming potassium 

 formate and chloride, and dichlorallylene C 3 H 2 C1 2 . Ni- 

 tric acid oxidizes it, forming trichlorcrotonic acid. 



Crotonal-ammonia (Oxytetraldin), C 8 H 13 NO. Is 

 produced when an alcoholic solution of acetic aldehyde- 



