54 KANSAS ACADEMY OF SCIENCE. 



CRYSTALLINE LIQUIDS * 



By Fred B. Porter, University of Kansas. 

 Read before the Academy, at Topeka, January 2, 1903. 



CRYSTALLINE LIQUID is a term that has come into use to de- 

 scribe a phase in which a few substances have properties of both 

 liquids and crystals. At certain temperatures these substances ap- 

 pear to the naked eye like ordinary liquids. They are free flowing, 

 but have a cloudy or milky appearance. Under the polarizing micrp- 

 scope, however, they show double refraction, a property of crystals. 

 At a higher temperature they suddenly lose the cloudiness and the 

 double refractive powers and attain the true liquid phase. The tem- 

 perature at which the solid changes to the cloudy liquid is the melt- 

 ing point, and the temperature at which the cloudiness disappears is 

 called the transition point. 



The first substance which was observed to have these peculiar 

 properties was Cholesterine benzoate (C36H43OOCC6II0), (Schenck, 

 Zeits. Phys. Chem. 25, 337). In 1887 Reinitzer, a German chemist, 

 observed that this substance melted at 145° to a cloudy liquid, and 

 that at 178' the cloudy appearance suddenly disappeared. He did 

 not, however, observe its double refraction. 



In 1890 three azoxyphenolethers, which had this cloudy modifica- 

 tion of the liquid state, were made and studied by Gatterman (Be. 

 23, 1738). The composition, melting points and transition points of 

 these substances are shown in the following table : 



Melting Transition 

 Name. Formula. point. point. 



Paraazoxyanisol, OH3OC6H4-N N-e6H40CH3 114° 134.1 



\0/ 

 Paraazoxyphenetol, C2H,OC«H4-N N-C6H4OC2H5 134.5° 164.2^ 



Anisolazoxyphenetol, CH.jOCoH^-N N-C6H4OC2H, 86° 116° 



\o/ 



Gatterman also found that these substances, when exhibiting this 

 cloudy appearance, have the property of double refraction. This he 

 observed by means of a special ajjparatus for heating the substance 

 under the polarizing microscope. Such an arrangement is necessary 

 to observe the double refraction in the crystalline liquids thus far 

 known, because none have been discovered that have the crystalline 

 liquid phase at ordinary temperature. 



The properties of the azoxyphenolethers have been further studied 



* Abstract of a thesis presented to the faculty of the School of Engineering of the University 

 of Kansas for the degree of bachelor of science in chemical engineering. The work was carried 

 on in the laboratory of organic chemistry, under direction of Prof. Edward Bartow. 



