Clean Technology For Synthesizing Naphthol And Their Derivatives

Naphthol,includingα-naphthol andβ-naphthol,is an important chemical intermediate.With their large market potential,their derivative proudets have great and important applications.There are many disadvantages in traditional industrial production way-sulfonated alkali fusion with complex production process,long process,equipment serious corrosion,waste,pollution and other major shortcomings. With the improvement of environmental requirements,Hydroxylation of naphthol with Hydrogen Peroxide is the optimum extraction process of producing naphthol, which is atomic economic reaction and has obtained considerable achievements. Hydroxylation of naphthol by aqueous hydrogen peroxide was undoubtedly the most efficient and prospective route.It will promote the green synthesis techniques of industrial naphthol and lay a foundation for early realization of naphthol green industrial production.In addition,synthesizing 2-naphthol ramification-naphthyl ethers with microwave technique was researched.A new method of directly producing naphthol from naphthalene is studied,in which iron oxides inγ-Al₂O₃ as Carrier is used as catalyst and hydrogen peroxide is as oxidant.The effect of solvent,the molar ratio of hydrogen peroxide and naphthalene, the a mount of catalyst,reaction time and temperature on hydroxylation of naphthalene are discussed.The experimental results show that:the solvent is acetone,the molar ratio of hydrogen peroxide and naphthalene is 5-7h,the amount of catalyst is 20%（according to the weight of naphthalene）,the reaction time is 7-8 hours,the reaction temperature is 50-55℃and the highest ratio of a-naphthalene can reach 45%. And the solvent used a mixture of acetonitrile and methylene chloride（1:1）,the reaction temperature 20℃and the reaction time 8 hours are better for producing 2-naphthol.Zinc powder was found to be a highly efficient catalyst for the synthesis of naphthyl ethers using microwave heating in the presence of N,N-dimethylformamide as well as under stirring in an oil-bath using tetrahydrofuran as solvent without any inorganic base.The effect of solvent,the mount of catalyst,reaction time and temperature on the Williamson ether synthesis are discussed.This method can be used for selective naphthyl ethers.In conclusion,we describe a novel and highly efficient procedure for the Williamson ether synthesis catalyzed by Zn powder under microwave.We studies the synthesis ofβ-naphthy ethyl ether under microwave radiation.The experimental results show that the solvent DMF is 3ml,the amount of catalyst is K₂CO₃ 3.04g（22mmol）,2-naphthalene is 2.88g（20mmol）,Bromoethane2.188g （20mmol）,the reaction time is 20min,the microwave radiation power is 320w.