Coal liquefaction ‐ entrapment of bitetralyls and other products from tetralin

Abstract

AbstractSmall scale coal liquefaction experiments are often carried out with tetralin as a model hydrogen donating solvent1–4. Tetralin was thought for a long time to be selectively converted into naphthalene. Recently, however, we have found substantial cracking and isomerization of tetralin under common coal liquefaction conditions, in particular at prolonged reaction times5. The present paper describes further studies of the behaviour of tetralin during coal liquefaction at 400°C, whereby special attention is given to the formation of bitetralyls. Entrapment of these relatively low‐volatile compounds strongly influences data obtained for the coal derived product. This means that the common procedures used to separate coal product and donating solvent are highly insufficient. The structure of the entrapped dimer tetralin compounds has been determined and the mechanism of dimerization is discussed.