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Naphthalene is an important organic chemical material which widely used in synthetic fibers, synthetic resin, plasticizers, rubber antioxidant, dyestuff intermediates, medicine, Sanitary materials and some new chemical industry. It also be used to produce phthalic anhydride,β-naphthol,α-naphthylamine, the proliferation of agents, H acid and other chemical products. Naphthalene are produced in two ways which chemical synthesis and naphthalene oil separation. But naphthalene oil separation method is used widely. Naphthalene oil separation is not very perfect measuring instrument because it is not accurate enough, distillation tower reflux ratio are not carefully controlled, and so on.The production of naphthalene are not high quality and applications is limited. Naphthalene produced in the separation of naphthalene oil, when we found another type of organic matter in the oil. Phenolic compounds are mainly used in synthetic fibers, engineering plastics, pesticides, pharmaceuticals, dye intermediates, plasticizers, preservatives, antioxidants, and the production of explosives, etc.And the recovery process is simple, high efficiency of recycling. The process not only purified industrial water but also for enterprises to create economic efficiency.Distillation method are used to separate low temperature fractions of coal. Naphthalene and phenol content were measured by GC,finally deciside to use spiral-shaped stainless steel column,φ3mm×3m; column temperature 150℃; vaporization temperature 250℃; protection of temperature 300℃; carrier gas was nitrogen, hydrogen pressure is 0.5Mpa pressure. Determination of phenolic compounds out of the average relative mass correction factor fm ’= 1.215, naphthalene relative mass correction factor of 1.2199.Recovery of phenol from naphthalene oil mainly by alkaline cleaning and acid washing steps, and adding NaOH to the solution of naphthalene oil to make a good water-soluble compound to separate naphthalene oil, and then adding acid to the solution and the reaction of phenol in order to achieve the purpose of refining, Through orthogonal experiment, a more reasonable alkaline wash conditions was deceded: NaOH (4mol / l) 50g: 7ml, reaction time 1.5h, heating temperature 80℃, holding time 40 min. Pickling acid to sulfuric acid when used, will be controlled at 30% concentration of sulfuric acid, adding the temperature 80℃~ 92℃, pH 5 to 7, the refining of crude phenol is better. Preparation of refined naphthalene use the methods of crystals and hydrogen. Crystallization process are tested that the cooling rate impact on the fine quality of naphthalene. Rapid cooling will wrap the solution in crystal ,so quality of naphthalene decreased, eventually cooling speed positioning 1℃/ h, the lowest crystallization temperature at 40℃~ 60℃range. Hydrogenation when hydrogen pressure was 0.5 ~ 1.0Mpa, hydrogenation time was 1.5min ~ 2.0min, operating under this conditions can be refined to achieve better results.
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