Substitution reactions aging" effects

The effect of acidity caused by alum-rosin size has been obviated by the substitution of sizing agents which are effective slightly on the alkaline side of neutrality. It has been established that papers of satisfactory permanence can be manufactured with such sizes. It is possible to use rosin as a size and to avoid the conjunction with alum by a number of processes. There are insufficient data on the aging characteristics of paper sized with the available modified rosin sizes to judge the effect on permanence. Possible reactions of the rosin, such as oxidation and formation of peroxides, must be considered. 

Figure 7.13 demonstrates the accelerating effect of increasing nitrogen content on the activity in aging of activated carbons from phenol-formaldehyde resin, in which part of the phenol was substituted by aniline [164]. The surface area was from 700 to 840 m /g. The oxidation rate increased almost linearly with the nitrogen content. Conversion to carbonate proceeds much more slowly at room temperature reaction times of one to two months were necessary to obtain well-measurable results [163]. 

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