Scientific and other notes on essential oils. 73 



Wood turpentine oil and similar products. Cellulose is produced generally for the 

 manufacture of paper according to two different processes, vie., the sulphite and the 

 soda process. In Germany, the former process is principally worked, although the 

 waste liquors which are produced thereby, for which hitherto a practical application 

 has not been found, are a cause of great annoyance to the manufacturers. The soda 

 process has the advantage of permitting the utilization of wood rich in resin (from 

 coniferous trees); the manufacturing costs, however, are higher and it is by no means 

 easy to obtain a licence for manufacturing, as the smell of the cooker liquors is very 

 disagreeable. The losses of soda are covered in this process by the addition of sodium 

 sulphate, after which extraction takes place in the usual manner and burnt lime is 

 used as a caustic. The sodium sulphate is hereby partly transformed into sodium 

 sulphide which acts on the fibres in the same manner as caustic soda solution; 

 accordingly the method is also called the sulphate process and the cellulose produced 

 thereby "sulphate cellulose" 1 ). A by-product resembling oil of turpentine is obtained 

 according to this method, which originates from the portions of the wood rich in 

 resin. This oil is blown over by the steam after the termination of the boiling process 

 and is then condensed in a suitable receptacle outside the cooker. According to 

 O. M. Halse and H. Dedichen 2 ), the quantity of oil produced in this manner varies to 

 a great extent, as it depends on the content of resin compounds in the wood. Ordinary 

 pine wood generally gives a yield of 1 to 1.5 kg. per ton of cellulose, whereas wood 

 from Scotch pines produces as much as 10 kg. per ton of cellulose. 



In a crude state the oil has a detestable smell which is caused by the presence 

 of mercaptanes and of other organic sulphur compounds, e. g., of methyl sulphide. 

 For using it as a substitute for ordinary oils of turpentine, these substances must be 

 removed as much as possible. A number of patent processes are already known for 

 this purpose which mostly depend on a careful oxidation of the sulphur compounds, 

 for instance by the effect of air or light. In some works also fractionated distillation 

 is employed, and by this means the sulphur compounds, owing to their boiling point 

 being lower than with the oil, can be almost completely removed. 



The authors examined the crude volatile oil, just as it usually comes from the 

 works, without its having been purified. It smelt in a most disagreeable manner of 

 mercaptane and accordingly they began by treating it first of all with an alcoholic 

 solution of mercuric sublimate, after which they distilled it in the ordinary manner 

 by the aid of steam. Hereby a viscous brown liquid remained as a residue, forming 

 about 8 per cent, of the oil, and consisting of the ordinary resin-like oxidation products 

 of oil of turpentine. 



The purified oil was colourless and clear; it smelled of fresh wood, but was 

 otherwise quite like gum oil of turpentine. The constants observed were: dj§ 0.8657 

 and 0.8641; « D20O + 1 7.05 and +18.55°; n D20O 1.47151 and 1.47270. The oil dissolves 

 in 5.5 vols, of 90 per cent, 25 vols, of 80 per cent., and 70 vols, of 70 per cent, alcohol. 

 It boiled mainly between 154 and 155° and between 167 and 168° and consisted 

 principally of d-o-pinene, which was recognised as such by oxidation to pinonic acid. 

 The semicarbazone had its melting point at 203°. The presence of /?-pinene was 

 effected by the formation of nopinic acid, melting point 123°; it is present in this oil 

 in a deatfrorotatory form, whereas hitherto it was only known as a laevorotatory product. 

 The authors are unable as yet to determine whether the j#-pinene exists in a dextro- 



*) O. Dammer, Chemisette Technologie der Neuzeit, Stuttgart 1911, vol. Ill, p. 8. — -) Berl. Berichte 50 

 (1917), 623. 



