Hydrogenation of brown coal. IV Model compound studies and mechanistic considerations

A series of lignin-related phenyl, benzyl and alkyl ethers have been reacted with hydrogen in the presence of iron (II) acetate and tin metal as additives. Iron reduced the rate of reaction of the phenyl ethers and increased the rate of reaction of the benzyl and alkyl ethers compared to the reactions without additive. Tin decreased the rate of reaction of the phenyl and benzyl ethers and had no effect on the reaction of the alkyl ether. Neither iron nor tin changed the products from the reactions of the ethers compared to the reactions without additive. The results are discussed in terms of the use of iron and tin compounds as additives in coal liquefaction reactions.