This work is to study the reactions of coals with water. All the reactions of Yokote peat (C=60.3%) and Wakimoto Seam II lignite (C=62.2%) with water were carried out in a batch-autoclave at 300-400°C under hydrogen starvation conditions. Two kinds of catalysts, alumina-supported MoO
3 and WO
3, were used. WO
3 catalyst facilitated the reactions of peat and of lignite with water to give much larger amount of benzene-soluble matter and gaseous product than that of non-catalytic reaction, whereas MoO
3 catalyst was practically inert toward the reactions of these coals.
Otherwise, the reactions of benzyl ether with water were performed on both the catalysts, respectively, to elucidate the above mentioned experimental results of coals. On MoO
3 catalyst were formed dibenzyl and equimolar toluene and benzaldehyde. This suggests that MoO
3 catalyst promotes mainly the following reactions:
Ph-CH
2-O-CH
2-Ph→Ph-CH
3+Ph-CHO (I)
Ph-CH
2-O-CH
2-Ph→Ph-CH
2+Ph-CH
2-O (II)
Ph-CH
2-O+Ph-CH
2-O-CH
2-Ph→Ph-CH
2-OH+Ph-CH-O-CH
2-Ph (III)
Ph-CH-O-CH
2-Ph→Ph-CHO+Ph-CH
2 (IV)
2Ph-CH
2→Ph-CH
2-CH
2-Ph (V)
On the other hand, product relatively abundant in benzyl alcohol and benzaldehyde was given on WO
3 catalyst, indicating that hydrolysis of benzyl ether and subsequent dehydrogenation of benzvl alcohol take nlare mainly:
Ph-CH
2-O-CH
2-Ph+H
2O→2Ph-CH
2-OH (VI)
Ph-CH
2-OH→Ph-CHO+H
2 (VII)
Summarizing the above experimental results and considerations, it may be clai-med that WO
3 catalyst facilitates hydrolysis of ether bond in structures of lignite and peat forming molecules such as alcohol or aldehyde type ones as shown by reactions (VI) and (VI). This, overcoming the competing condensation reactions, leads to produc-tion of benzene-soluble matter. Meanwhile, MoO
3 catalyst, irrespective of the presen-ce of water, splits some chemical bonds such as C-C and C-O to give a large amount of radical as shown by reaction (II). This is due to hydrogen starvation and results in the polymerization reactions, such as reaction (V), instead of depolymerization.
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