Origin of the Carboxylic Acids

To various extents, the pentosan chains of the raw material have acetyl, formyl, and other such groups attached [53]. The ratio of acetyl to formyl groups is usually in the order of 10 1. 

A typical birch wood pentosan has its acetyl apportioned in such a way that 58 percent of the rings are free from acetyl groups, 24 percent are acetylated at C-3, 12 percent at C-2, and 6 percent have acetyl groups on both C-3 and C-2. 

The hydrolysis of a doubly acetylated pentosan to pentosan and acetic acid is depicted below  

This hydrolysis is the easiest decomposition, and therefore the first to occur. As all hydrolyses, it is catalyzed by acidity, so that the liberation of carboxylic acids is exponential The first formation of acids catalyzes the liberation of more acids, and so forth. This is of great importance for autocatalytic operation as in the ROSENLEW process. 

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