Synthesis And Refining Of High Purity 2,6-dihydroxynaphthalene

2,6-Dihydroxynaphthalene is used widely in fiber,resin,packaging containers,film,dyestuff and medicine etc,which is also used as monomer in the manufacture of high performance polyester resins.2,6-Naphthalenediols was prepared by alkali fusion with sodium 2,6-naphthalenedisulfonate or Schaffer's potassium as reaction material.All kinds of flow aiding agent were added in alkali fusion reaction to study whether they could help alkali fusion reaction.The effects of temperature,time,the ratio of reaction material and the content of inorganic salt in sodium 2,6-naphthalenedisulfonate to alkali fusion were also researched.When sodium 2,6-naphthalenedisulfonate was used as reaction material,flow aiding agent X was added to decrease material viscosity and increase mobility,reliving peroxidation,coking,local overheating etc,reducing the amount of alkali fusion agent,further reducing the discharging capacity of waste water and gas,improving the yield and purity,cutting production costs.When sodium 2,6-naphthalenedisulfonate was used as reaction material,the optimal alkaline fusion technical conditions: the mass ratio of disodium 2,6-naphthalenedisulfonate,NaOH and KOH 1:2.4:2.0,the mass ratio of mixed alkaline,flow aiding agent X 10:1,nitrogen atmosphere,reaction temperature 345?,reaction time 1h,the yield of 2,6-dihydroxynaphthalene was about 90%.When Schaffer's potassium was used as reaction material,the optimal alkaline fusion technical conditions: The mass ratio of Schaffer's potassium,NaOH and KOH 1:1.12:1.12,nitrogen atmosphere,reaction temperature 345 ?,reaction time 2h,the yield and purity of 2,6-dihydroxynaphthalene was about 85.34% and 82.88%.Refining with mixed solvents,five kinds of composite solvent(alcohols-alcohols mixed solution,alcohols-acids mixed solution,alcohols-esters mixed solution,alcohols-ketons mixed solution,alcohols-water mixed solution)were selected to refine the crude product.Under the optimal refining technical conditions,the ratio of the crude product of 2,6-dihydroxynaphthalene,methanol,propionic acid and water was 1:1.5:1.5:1.5,the mass ratio of the crude product of 2,6-dihydroxynaphthalene and sodium carbonate 200:3,the mass ratio of the crude product of 2,6-dihydroxynaphthalene and active carbon 5:1,the purity of product was up to 98% and the yield was about 66%.