This study was carried out with a object of determining structural characteristics of reductive alkylation product.
Benzene soluble portion (BS-1) prepared from Taiheiyo coal was used as the starting materials. BS-1 was repeatedly methylated three times without using naphthalene, since BS itself plays a role of an electron transfer agent.
The n-hexane soluble portion (HS) and the BS from the 1∼4 reductive methylation steps were separated by gel permeation chromatography, and the molecular weight distributions of them were determined using a vapor-pressure osmometry. HS at each step was also separated into six relatively distinct compound types-saturates, monoaromatics, diaromatics, etc-through dual-packed column to examine the contents of these type-compounds. Furthermore some of HS-GPC. fractions, molecular weight range 602∼283, were analysed by gas chromatography/mass spectrometry.
From these results, it was clearly observed that the change of high molecular weight fractions into lower ones, the transfer of benzene eluate into polar mixture and methanol eluates, and the convesion of type-compound with Z No.-22 into that with Z No.-18 had occurred by step-wise methylation.
Thus unit structure of coal had a tendency to be gradually uniformized.
