The Abstraction Of Fluorene And Dibenzofuran From Gas Absorber Oil

Fluorene and dibenzofuran are important chemical materials, which are mainly used for preparation of medicines, synthesizing dyes and accessory ingredients etc.It is really worthwhile expanding the market.There are two ways to produce fluorene and dibenzofuran in general, synthesis and separation. The cost of synthesizing way is high, while the separating way from material containing fluorene and dibenzofuran is economical. There are abundant fluorene and dibenzofuran consist in gas absorber oil from coal tar fractions. The abstraction of fluorene and dibenzofuran from gas absorber oil not only gets fluorene and dibenzofuran as great value products, but also improves the capability of the oil for absorbing benzene and helps to separate other components consisting in the oil.The contents of main components in crude gas absorber oil were analysed with GC in the thesis. A research project of abstracting fluorene and dibenzofuran from gas absorber oil was put forward, based on the generalization and comparison of existing methods of separation and purification of fluorene and dibenzofuran. The main research contents include following aspects:(1) Rectification experiments of gas absorber oil: Gas absorber oil was rectificated at different reflux ratios and different temperature fractions were intercepted. After analyzing the contents and mass of every component in different temperature ranges fractions, the effect of reflux ratios on the separation result of every component was discussed, and the temperature range of fluorene fractions and dibenzofuran fractions were ascertained.(2) Twice rectifications of the oil: The intercepted fluorene fractions and dibenzofuran fractions were separated into high content fractions and low content fractions, then high content fluorene fractions and dibenzofuran fractions were rectificated respectively and every fraction components were analysed.(3) Purification experiments of fluorene and dibenzofuran: The high content fluorene and dibenzofuran fractions were recrystallized with different solvents respectively, and the recrytallization conditions with different solvents were reserached, the purity and yield of the recrystaled products were analysed.Research results show that:(1) The appropriate reflux ratio is 10:1. The best intercept temperature range of fluorene fraction is 280～290℃and the best intercept temperature range of dibenzofuran fraction is 272～280℃, under Taiyuan area atmosphere pressure.(2) The high purity fluorene and dibenzofuran can not be obtained by the method of rectification for two times. The low content fluorene and dibenzofuran fractions can not be recrystallized purification until they are converted into high content fluorene and dibenzofuran fractions by rectificating for two times.(3) The purity of high content fluorene fraction can be great improved by recrystallization and lavation in turn. Thereinto, the effect with toluene as recrystallization solvent is better than ethanol, and rough fluorene of purity 93% can be obtained after recrystalling; While the effect with ethanol as lavation solvent is better than methanol, and fined fluorene of purity >97% can be obtained after the rough fluorene is washed.(4) Recrystal is effective method for high content dibenzofuran fraction purification. The experiments discover that: the purification effect withα-methylnaphthalene fraction as recrystal solvent is better than ethanol, toluene, ethylene glycol, and dibenzofuran of purity >96% can be obtained by recrystallization for two times.(5) The technology of abstracting fluorene and dibenzofuran from gas absorber oil offered in this thesis has outstanding advantages, such as simple process, low energy consumption, high product purity, nearly no pollution and so have prospect for industrialization.