ORGANIC CHEMISTRY 



ir 



explain this difference another form of asymmetry is supposed 

 to occur, namely, that a ring containing oxygen is formed. 

 CH 3 C H H C OCH 3 



CH 2 OH 



a-Methyl glucoside 



CH 2 OH 

 /3-Methyl glucoside. 



Glucose is assumed to occur in these two forms, an hydroxyl 

 group replacing the methoxy (CH 3 O) group. Glucose 

 solutions show a variable effect on the rotation of polarised 

 light (muta-rotation), which is due to the inter-conversion of 

 the a and p varieties. The stable condition is an equilibrium 

 condition between the two varieties. The equilibrium varies 

 with the concentration and temperature, hence these must 

 be kept constant in making measurements. A trace of alkali 

 is frequently added to the solution to hasten the condition of 

 equilibrium. Other forms of glucose, such as y-glucose are 

 important in biological processes. 



For further information the reader must be referred to the 

 monographs on carbohydrates. 



FATS 



As already mentioned the oxidation of a primary alcohol 

 produces an aldehyde and then an acid. The oxidation of 

 the marsh gas series produces what is termed the fatty acid 

 series. The fatty acids consist of a chain of carbon atoms ; 

 each succeeding compound containing one CH 2 group 

 more than its predecessor. As the number of carbon atoms 

 increases the acids become less soluble in water and their 

 melting points rise. Formic and acetic acids are liquid at 

 moderate temperatures, and' they mix in all proportions 

 with water, but the higher fatty acids which occur in the 

 usual fats are solid and do not dissolve in water. 



H-COOH CHjCOOH 



Formic Acid. Acetic Acid. 



CH 3 (CH 2 ) 16 COOII 



Stearic acid. 



CH 3 (CH 2 ) 14 COOH 



Palmitic Acid. 



General formula. 



