Solubilities Of NSA And NaNS In Aqueous Sulfuric Acid Solutions And Their Application

2-Naphthalenol is a kind of useful organic product in the making of dyestuffs,Rubber,medicine,spices and other materials.The present industrial process of producing 2-Naphthalenol is sulfonation-alkali fusion from naphthalene.The process includes four steps: sulfonation,neutralization,alkali fusion and acidification.China is the largest 2-naphthalenol producer in the world,and sulfonation-alkali fusion method is widespread used in 2-naphthalenol production.However sulfonation-alkali fusion method has its serious shortcomings such as complex process,serious environmental pollution and the huge labor intensity.This limits the development of 2-naphthalenol production technology.So,the production process of 2-Naphthalenol needs to be improved.In order to improve the production process of 2-Naphthalenol,the solubility data of 2-Naphthalenesulfonic acid?NSA?and sodium 2-naphthalenesulfonate?NaNS?in aqueous sulfuric acid solutions were measured using a dynamic method.The solubility data of NSA and NaNS increase with temperature,and both of them have the lowest solubility at w₃⁰ =0.70 and the highest in pure water.Under the same condition,the solubility of NSA is not less than NaNS,the solubility difference between NSA and NaNS increases with temperature and decreases with sulfuric acid concentration.The solubility difference between NSA and NaNS is close to zero in low temperature condition or high concentrations of sulfuric acid aqueous solution.Because of the complex of the dissolution phenomenon of NSA and NaNS in aqueous sulfuric acid solutions,the solubility data were correlated by the Apelblat equation.The root-mean-square deviation of NSA and NaNS in sulfuric acid aqueous solutions ranged from 0.40 K to 0.94 K and 0.11 K to 0.62 K,respectively.The calculated results showed good agreement with the experimental data.Based on the solubility difference between NSA and NaNS,a new strategy in which sodium sulfate was used to replace sodium sulfite in the neutralization reaction was proposed.The suitable mole ratio of H2 O to Na2SO4 in the neutralization reaction was set as 80,and the mole ratio of NSA·H2O to Na2SO4 was determined as 3.2.The material balance under the suitable mole ratios was given and discussed.