SCIENCE AND INDUSTRY. 
Wood Distillation. 
By A. J. HALL, B.Sc. 
The dye industry is vitally connected with coal-tar distillation, and 
in recent years this connexion has been widely discussed. There are 
‘few dyestuffs that are not in one way or other derived from coal and 
‘its by-products. _ But coal is not alone in providing the dye manufac- 
turer as well as the dyer with useful substances. Wood is an important 
raw material. By the dry distillation of wood, many useful by-pro- 
ducts are obtained, and until further synthetic methods are discovered 
the production of such substances as methyl alcohol and formaldehyde 
will depend on this industry. At present, wood distillation is to a large 
extent supplying the demand for acetic acid, acetone, methyl alcohol, 
sodium and calcium acetates, formaldehyde, and charcoal. To a — 
smaller extent wood yields several chemicals of value in medicine. 
A CompLex Supsrance, 
Wood itself is a complex cellulose substance which will obviously have 
a composition dependent on its source. Hard woods are essentially 
different from soft woods. Cellulose and lignin are the chief consti- 
tuents of wood. The various processes in paper manufacture are 
carried out with the object of separating these two substances, and at 
present the lignin liquors are a waste product which is awaiting a 
useful application. 
England is not a country rich in timber, and, consequently, the 
greater proportion of wood distillation plant is situated abroad. Be- 
fore the war, Germany carried out a great deal of wood distillation, 
and this industry was especially flourishing there. 
Wood always retains a certain amount of moisture, and in the 
distillation it is customary to employ the wood in its ordinary air-dry 
condition. It will be noticed from the average composition of wood 
that no nitrogen products are present. Hence there are no nitro- 
geneous substances among the products of distillation. In the car- 
bonization of bones, which contains a large proportion of nitrogen, a 
considerable amount of methylamine is obtained. In wood distillation 
hydroxy bodies as methyl aleohol are obtained. The average composi- 
tion of dry wood is:— . 
_ Carbon fe ¥ ty, .. 50.00 per cent. 
! Hydrogen ae qe SiH Ei es 
Oxygen ise ot Hy see MG A an 
Ash t3 Ab EY tery ee 
It is but natural that attempts have been made to establish a rela- 
tion between the final by-products and the original constituents of the 
wood. So far it would seem that, while both the cellulose and lignin 
give rise to carbon, acetic acid, and tar, the lignin differs from the 
cellulose by decomposing into less oxidized bodies such as methyl 
alcohol and acetone. Of course, no separation of the cellulose and 
so aa hs MA a A cas ls lee UE 
} Extract from The Dyer and Calico Printer, 1st October, 1920. 
686 
