Info

144 47.5 55.8 §3.7 91.0

A and B different samples of charcoal.

A and B different samples of charcoal.

The amount and composition of the gas given off when a charcoal is heated to various temperatures higher than that at which it was produced is shown in Table 16, also taken from Bergstrom and Wesslen.18 6

The methane content of the gas from sample B when calculated to methoxyl gives nearly 7 per cent methoxyl on the weight of the char-

coal, or about 2.5 per cent on the weight of the original wood. This is more methoxyl than has been found in charcoal by analysis (see p. 60) and indicates either that some of the methoxyl groups in charcoal are so inactive that they are not acted on*by the analytical treatment or that at these higher temperatures some methane may be formed from some other source besides methoxyl groups. The former is the more likely assumption.

The nitrogen content of two samples of charcoal is given by Bergstrôm and Wesslén as 0.15 per cent. This indicates that about one-fourth of the nitrogen in the original wood remains in the charcoal.

In general then the distillation of wood produces in large amount certain very simple substances as water, carbon dioxide, methane, acetic acid, methyl alcohol, formaldehyde, and acetone, and in much smaller amounts the higher homologues of some of these simple compounds; the pyrrol ring is-represented by a few compounds and the benzene ring is found almost entirely in the alkali soluble constituents of the tar. Polymerization and condensation products of the simpler compounds are found probably along with the still higher members of the series mentioned, which are so complex and inactive that they can not be identified. Most of the products are less complex than the original lignocellulose, but the charcoal and probably part of the pitch are apparently residues of even more complex composition than lignocéllulose.

From these general statements the lignocellulose can be pictured as containing hydroxyl, methoxyl, acetyl and formyl groups on a structure of benzene and pyrrol rings. Whatever other structures may be present are not indicated by the distillation reaction.

The marked differences from the products of distillation of coal are in the lack of nitrogen compounds, of benzene, naphthalene, anthracene and similar hydrocarbons, and of the simple phenols; and in the presence of the compounds with methoxyl, formyl and acetyl groups.

0 0

Post a comment