Title:  Isocrotonic Acid 
CAS Registry Number:  503-64-0 
CAS Name:  (2Z)-2-Butenoic acid 
Additional Names:  cis-2-butenoic acid;  cis-crotonic acid 
Molecular Formula:  C4H6O2 
Molecular Weight:  86.09 
Percent Composition:  C 55.81%, H 7.02%, O 37.17% 
Line Formula:  CH3CH=CHCOOH 
Literature References:  Prepd by reacting acetaldehyde with malonic acid in the presence of pyridine:  v. Auwers et al., Ann. 432, 46 (1923); from ethyl acetoacetate:  Hatch, Nesbitt, J. Am. Chem. Soc. 72, 727 (1950); from but-2-ynoic acid:  Allan et al., J. Chem. Soc. 1955, 1862; from CH3CH=CHMgBr + CO2:  Normant, Maitte, Bull. Soc. Chim. Fr. 1956, 1439.  Structure:  v. Auwers, Wissebach, Ber. 56, 715 (1923); Plisov, Bogatskii, Zh. Obshch. Khim. 27, 360 (1957), C.A. 51, 15401c (1957).  Review:  W. Blau et al., in Ullmann's Encyclopedia of Industrial Chemistry vol. A8 (VCH, Weinheim, 5th ed., 1987) pp 83-89. 
Properties:  Liquid.  bp5 55-56°; bp10 62-64°; bp760 168-169°.  mp 15°; crystallized from pentane.  d420 1.0267.  nD14 1.4483.  nD20 1.4450.  uv max (95% ethanol):  205.5 nm (e 13500). 
Melting point:  mp 15° 
Boiling point:  bp5 55-56°; bp10 62-64°; bp760 168-169° 
Index of refraction:  nD14 1.4483; nD20 1.4450 
Absorption maximum:  uv max (95% ethanol):  205.5 nm (e 13500) 
Density:  d420 1.0267 
  
Derivative Type:  Methyl ester  
Molecular Formula:  C5H8O2 
Molecular Weight:  100.12 
Percent Composition:  C 59.98%, H 8.05%, O 31.96% 
Properties:  Liquid.  bp 118°.  nD20 1.4175.  uv max (95% ethanol):  205.5 nm (e 14000). 
Boiling point:  bp 118° 
Index of refraction:  nD20 1.4175 
Absorption maximum:  uv max (95% ethanol):  205.5 nm (e 14000) 
  
Derivative Type:  Benzyl ester  
Molecular Formula:  C11H12O2 
Molecular Weight:  176.21 
Percent Composition:  C 74.98%, H 6.86%, O 18.16% 
Properties:  Liquid.  bp10 121-122°.  nD20 1.5110. 
Boiling point:  bp10 121-122° 
Index of refraction:  nD20 1.5110 
  
CAUTION:  Can cause severe irritation of skin, mucous membranes.   |