

74 Report of Schimmel § Co. April/October 1917. 



rotatory form already in the wood or whether it is the result of the sulphate-cellulose 

 process, acting on Z-^-pinene. ^Probably, dipentene also exists in small quantities in 

 this oil. 



It is curious that «-pinene which otherwise does not belong to the most stable 

 terpenes stands the long boiling process of the cookers in the sulphate-method so 

 well, whereas in the sulphite-cellulose process it is converted into the more permanent 

 hydrocarbon ^-cymene. In this process the wood is boiled with acid sulphite liquor 

 and in point of fact the sulphurous acid is generally added in the form of a calcium 

 or magnesium bisulphite solution. Z. Kertesz 1 ) describes the formation of the volatile 

 oil in the manufacture of sulphite cellulose as follows: — After the termination of the 

 cellulose boiling the still unused sulphurous acid gases liberated are passed over into 

 a so-called mixing reservoir which contains fresh tower-liquor whose sulphurous acid 

 content is increased by the absorption of the sulphurous acid gases. Besides sulphurous 

 acid, much water vapour, acetic aldehyde, acetone, methylalcohol, furfurol, volatile 

 oils, formic and acetic acids are condensed. The fresh tower-liquor is diluted with 

 injection-water, the other condensation-products mix with the tower-liquor, on whose 

 surface the volatile oils accumulate and thereby prevent the oxidation and loss of 

 sulphurous acid. The liquor which has been carried over by the gases, the so-called 

 overwash-liquor, also accumulates in the tower-liquor. Part of them, especially the 

 volatile organic compounds, which are generated in the cookers in considerable 

 quantities at an elevated temperature, stream over into the fresh cooking-liquor and 

 circulate in this manner from one cooker to another. The compounds just mentioned 

 are, however, only represented by tolerably equal quantities, because part of them are 

 lost in the waste liquor and during the blowing-off of the cooker. 



The volatile oils formed in the sulphite process originate from the resin of the 

 pine wood. Schwalbe and Sieber 2 ) have ascertained that from pine wood which has 

 been stored for some time one can obtain by means of an ether-alcohol mixture 

 1 per cent, of substance, from fresh wood, however, 1.6 per cent. According to Sieber's 3 ) 

 latest publications, the pine wood contains 0.6 per cent, of resin or ether extract. 

 4.2 per cent, of this collects, owing to the boiling process, in the waste liquor or in 

 the condensation products, accordingly one ton of cellulose contains on an average 

 0.6 kg. of resin products which are probably generally represented in the form of a 

 volatile oil. Bergstrom estimated the quantity of oils obtainable at the figure of 1 to 

 1.5 kg. per ton; according to Kertesz' observations, the quantity produced varies 

 considerably and in fact depends on the varying resin content of the wood and on 

 the manner the cooking process is conducted. 



The volatile oils of the sulphite-cellulose manufacture were first examined by 

 Klason 4 ) who recognised cymene as being the main product. Bergstrom 5 ) believed 

 in the presence of terpenes, sesquiterpene, diterpene, and of terpene alcohol, without, 

 however, succeeding in isolating any of them. Later on, he extracted an inactive 

 borneol, melting point 203°, by congelation from the heavy oil which, besides other 

 compounds, contained furfurol. 



The brown-coloured oil originating from the pine wood which can be collected 

 from the surface of the cooking liquor in the mixing reservoir in a wholesale manner 

 has also been investigated by Kertesz; it still contained 0.6 to 0.8 per cent, of sulphurous 

 acid. It can be freed from the latter and from humidity by treatment with calcium 



*) Chem. Ztg. 40 (1916), 945. — 2 ) Verein der Zellstoff- u. Pdpier-Chemiker, Sommerversammlung 1914, 

 p. 16. — 8 ) Papierfabrikant 13 (1915), 389. — *) Berl. Berichte 33 (1900), 2343; Report April 1901, 67. — 

 5 ) Scensk Tappers Tidning 11 (1914), 130; Papierfabrikant 12 (1914), 1040. 



