Oxidative cleavage of lignin aromatics during chlorine bleaching of kraft pulp
Methanol liberation and methoxyl loss during chlorine bleaching of softwood kraft pulp were quantitatively investigated to estimate the degree of structural modification of lignin aromatics. An increase in the chlorine multiple led to enhanced methoxyl loss from lignin. Our result, using pH-adjusted chlorine water (pH 5.7), by which chlorination under oxidation-favorable conditions was achieved, strongly supported the importance of the oxidation reaction by chlorine during delignification and lignin degradation. It was also suggested that methanol can be produced not only via catalytic hydrolysis by chlorine but via oxidative cleavage of the ether bond as well. The infrared spectrum of chlorolignins suggested that chlorine oxidation can open aromatic rings to muconic acid derivatives without cleaving ether bonding of the methoxyl group. No straight relation between the methoxyl content and the kappa number of chlorinated pulps was shown. The methoxyl content of bleached kraft pulps subjected to successive chlorination and alkali extraction showed a good relation with the kappa number. This means that almost all the portions of the oxidatively modified lignin structure were successfully removed during these treatments, and the aromatic structures of residual lignin in chlorinated and alkali-extracted pulps were thought to remain intact.
The Structural Characteristics of High Molecular Weight Chlorolignin Produced by Chlorine Bleaching of Kraft Pulps
Three types of kraft pulps (unbleached softwood. unbleached hardwood and oxygen prebleached hardwood kraft pulps) were chlorinated at various levels of chlorine ratio (0.1-0.3) and residual chloroorganics in pulps were extracted in high yields by aqueous dioxane. Neutral sugar contents of these extracts were in the range of 1 to 5%. Extracted chloroorganics were treated by aqueous alkali in a similar condition as the E 1-stage of bleaching. Structural features of extracted chloroorganics and their alkali-treated products were analyzed by' H-NMR spectroscopy. FT-IR spectroscopy and others. These results revealed that the structures of chloroorganics were quite different from that of native lignin. Only few aromatic protons are observed in' H-NMR spectra. Instead of this, chloroorganics are very rich in methyl, methylene and methine structures and carboxylic acids. Model experiments using milled wood lignin (MWL) revealed that these structural features can be reasonably explained by the structural modification, especially by an oxidative ring opening, of residual lignins in unbleached kraft pulps during chlorine treatment.
The Forum: The Puzzle of Marketing Costs
BY the mid 192o's considerable information was available showing that the cost of marketing goods was approximately equal to the cost of their production. Census figures indicated that many more workers were engaged in marketing and that the proportion of those engaged in marketing had been increasing for several years. Available figures suggested that more capital was used in producing than in marketing goods and that many of the workers engaged in marketing were employed in retailing at relatively low wages.1 This presented a puzzle. If a great many more people were engaged in production than in marketing, we would expect the cost of production to exceed the cost of marketing; but the figures indicated that this was not the case. Some early teachers and writers reasoned that the cost of marketing had been very low when production was less specialized and that this cost had risen along with the increase in the division of labor and in the distances between buyers and sellers. In 1935· Lough and Gainsbrugh2 presented material showing that the cost of distributing manufactured goods through wholesale and retail channels decreased from 3i.4 per cent of retail value in 19091914 to 29.9 per cent in 1931 and that the cost of distributing all consumers' commodities through these channels declined