[HOWE] ISOMERIC PROPYLENE GLYCOLS 17 



Mono-Palmitate crystallised in white shiny crystals. It had a 

 melting point of 54-2°C. and a refractive index at 60°C. of 1-4405. 

 Solubility in 100 grms. absolute alcohol. 



at 15°C. 0-0907 grms. 

 ' at 0°C. 0-0193 " 

 The formula CH3CHOH CH2(Ci6H3i02) was shown by the following 

 analysis :— 



Saponification value 178-0 % Palmitic Acid 81-4 



Theory 178-25 Theory 81-5 



The very limited supply of the glycol available would not permit 

 of a determination of the position of the Palmitic Acid group in the 

 glycol, i.e. whether in positions 1 or 2 



Di-Palniitate had a melting point of 68-8°C. and a refractive 

 index at 75°C. of 1-4364. The white crystals obtained were large 

 and shiny. The di-compound always had a melting point higher than 

 the mono. 



Solubility in 100 grms. absolute alcohol, 

 at 15°C. 0-0115 grms. 



at 0°C. 0-00516 " 



The formula CH3CH(Ci6H3i02)CHo(Ci6H3i02) was shown by the 

 following analysis: — 



Saponification value 202-5 % Palmitic Acid 92-62 



Theory 202-9 Theory 92-75 



Palmitic Esters of Trimethylene Glycol 1,3. The temperature of 

 esterification for the palmitates was 171°C., but as the fat obtained 

 had a very high percentage of free acid, namely, 14%, this temperature 

 was about four degrees too low. It was impossible to repeat the 

 experiment as the supply of glycol was exhausted, and no more could be 

 obtained. Only the di-palmitate was crystallised from this charge. 

 Di-Palmitate was a white crystalline solid with a melting 

 point of 56-2°C. and a refractive index at 75°C. of 1-4374. 

 Solubility in 100 grms. of absolute alcohol, 

 at 15°C. 0-0517 grms. 



at 0°C. 0-0244 " 



The formula CH2(Ci6H3i02)CH2CH2(Ci6H.'îi02) was shown by the 

 following analysis : — 



Saponification value 202 • 6 ; 203 - 1 %Palmitic Acid 92 - 7 ; 92 - 8 

 Theory 202-9 Theory 92-75 



The solubility of the palmitates was found to be greater than that of 

 the stéarates. 



Comparison of the Fat Esters of the Glycols. The esters pf ethy- 

 lene glycol had a habit of crystallisation very similar to the esters of 



Sec. Ill, Sig. 2 



