Synthesis of α-naphthalene sulfonic acid

Highly pure α-naphthalene sulfonic acid was synthesized through sulfonated technology with naphthalene and gas of SO3 as raw materials by laboratory falling film type sulfonated device.The influences of n(SO3)∶n(naphthalene),gas volume fraction of SO3 and reaction temperature on content of α-naphthalene sulfonic acid were investigated.The results showed that the optimum synthesis conditions were as follows: n(SO3)∶n(naphthalene)=1.03∶1,the gas volume fraction concentration was 3%,and the reaction temperature was 95 ℃.The sulfonated conversion rate of α-naphthalene was 97.6% under the synthesis conditions.