Rigg. — Montan Wax. 273 



Crude Montanic Acid. 



Crude rnoutanic acid was extracted from montan wax by the following 

 process : 500 grams of montan wax were digested five times with hot alcohol, 

 about 3 litres for each extraction. This hot alcoholic solution, containing 

 practically the whole of the free acids, was siphoned off, neutralized with 

 ammonia, and the acids were then precipitated as calcium salts by means 

 of alcoholic calcium-chloride solution. The calcium salts were then filtered 

 off by means of a hot funnel. 



The crude calcium salts thus obtained were dried on the water bath, and 

 then pulverized and boiled out six times with alcohol. Motor spirit, although 

 a very good solvent of unsaponifiable matter, could not be employed for the 

 purification of the calcium salts, by reason of the almost unfiltrable paste 

 produced in this case. 



The calcium salts were now decomposed by glacial acetic acid, and 

 the crude acid thus obtained melted at 81-5°. Crystallization from motor 

 spirit raised the melting-point to 82-5°, but further crystallization from 

 alcohol, motor spirit, and acetic acid did not further raise the melting- 

 point. The acid crystallized from acetic acid in granules. 



The titration of the acid thus obtained, although the greatest care 

 was taken in the standardization of the decinormal solutions employed, 

 gave a molecular weight of 432 — i.e., almost the mean of the molecular 

 weights required for the formulae C 29 H 58 2 and C 28 H 56 2 . 



It thus appeared that either the montanic acid contained some inert 

 compounds such as hydrocarbons or ketones, or that it was admixed with 

 a higher acid. To test the first of these suppositions the acid was purified 

 by potash-lime saponification with an excess of lime, and then extraction 

 with hot motor spirit in which high-molecular-weight hydrocarbons and 

 ketones are readily soluble. The molecular weight of the purified acid, 

 however, remained unchanged (430). 



That the acid, although its melting-point was unaltered by further 

 crystallization, was not a single compound was demonstrated by submit- 

 ting 10 grams of the acid to fractional precipitation with magnesium 

 acetate, for the regenerated acids from the different fractions had the 

 following melting-points : — 



Melting-point. 



Fraction I (weight J^ of original acid taken) . . 85-5° 



II „ T 3 o „ •• 83-84° 



III „ T ±o „ .. 81-82° 



TV - 1 - 74-fi 



Fractional precipitation was therefore undertaken on a large scale. 

 50 grams of crude montanic acid were dissolved in 800 c.c. of alcohol, the 

 solution rendered alkaline with ammonia, and then precipitated with 20 c.c. 

 of a solution of magnesium acetate (equivalent to 10 grams montanic 

 acid). Four fractions were thus precipitated, and a fifth fraction was 

 obtained from the alcoholic filtrate on cooling. The regenerated acids 

 from these fractions had the following melting-points: — 



Melting-point. 

 Fraction 1 . . . . . . . . . . 83-5-84° 



2 

 3 

 4 

 5 



83-84° 

 82-83° 

 81-82° 

 74-76° 



