Research On The Synthetic Process Of 2-Diazo-1-Naphthoquinone-5-Sulfonyl Cloride

The compounds of diazonaphthoquinone have been extensively used in the positive photoresist of the positive presensitive plate. These compounds were discovered by Carle; a German Company in 1930s. Due to high seal force, complete resolution and high sensitivity especially in combined state with linear phenolic resin, these compounds are advantageous regarding their high tolerance and environment friendly nature.Naphthoquinone compounds are formed via 2,1-diazonaphthoquinone-5-sulfonyl chloride intermediate that reacts with compounds containing hydroxyl group and gives rise to photosensitive compounds. These resulting compounds are used in positive presensitive plate. The present work covers the synthesis of 2,1-diazonaphthoquinone-5-sulfonyl chloride intermediate with optimized reaction conditions through a safe and environment friendly synthetic routes.The reaction was carried out by adding 1-naphthol-5-sulfonic acid, hydrochloric acid dropwise and sodium nitrite successively with 1:1.2:1.7 mole ratio at 0-5 ℃ with stirring for 5 hours. The resulting compound 2-nitroso-l-naphthol-5-sulfonic acid was filtered, washed with water and dried in vacuo; the yield was 97%.In the second step,2-nitroso-l-naphthol-5-sulfonic acid was allowed to react with Raney Nickel or Palladium/Charcoal catalysts for reductive hydrogenation in autoclave. The reduction product 2-amino-l-naphthol-5-sulfonic acid hydrochloride was obtained with 95% conversion and 97% chemoselectivity. The reaction was carried out at 50-70 ℃ with catalyst loading of 3%.In the third step,2-amino-l-naphthol-5-sulfonic acid hydrochloride was made to react with copper sulphate (an oxidant), sodium nitrite and hydrochloric acid that resulted in the synthesis of 2-diazo-l-naphthol-5-sulfonic acid with 96% yield.In the finally step,2-diazo-l-naphthol-5-sulfonic acid was allowed to react with phosphoric trichloride as catalyst, chlorosulfonic acid and sulfoxide chloride as acyl chlorinating agent that gave rise to 2-diazo-l-naphthoquinone-5-sulfonyl cloride as orange yellow solid with 75% yield.