| Naphthol,commonly known naphthol,is a class of amide compounds for the preparation of ice dye and organic dye.It is coupled with the chromophodic diazo salt on the fiber to form insoluble azo dye,It is mainly used as dyeing agent for cotton fiber,printing base and printing ink.Its application prospect is broad.However,the production of waste salt and waste acid in the traditional synthesis process has seriously limited its development,so it is necessary to develop a new production process.Based on this,In this paper from the direct catalytic amidation to the formation of amide,Naphthol AS-PH was successfully synthesized by two synthetic systems using appropriate amidation catalysts.On this basis,the substrate was expanded to form a set of production technology of similar products,The details are as follows.The first synthesis system uses o-ethoxyaniline as both reaction material and solvent,Naphthol AS-PH was synthesized from 2-hydroxy3-naphthalic acid and o-ethoxylaniline,The molecular structure of the product was characterized by nuclear magnetism and liquid phase,The influence of catalyst type,catalyst dosage,reaction temperature,reaction time and material ratio on the reaction was discussed.Studies have found that o-ethoxyaniline as solvent,using 20mol% of phenylboric acid as catalyst,2-hydroxy-3-naphthalic acid and o-ethoxyaniline ratio of 1:8,170? reaction3.5h,under the optimum synthesis conditions,the yield of naphthol AS-PH can reach more than 80%,catalyst through four recycling still have catalytic activity;on this basis,the influence of the volume ratio of methanol/amine and the application times of mother liquor on the product purity was discussed,The results showed that the amount of anhydrous methanol was V(anhydrous methanol):V(o-ethoxylaniline)=2:1,the product purity reached more than 99%.Product whose purity is reduced due to repeated use of mother liquor,it can be refined to meet the requirements.Usingactivated carbon(the dosage is 3% of the mass of o-ethoxyaniline),stirring and washing the mother liquor at 60 ? for 2h,can effectively absorb impurities in the mother liquor,control the content of alkali insoluble substances in the product,and the mother liquor can be applied for up to 20 times;Darker products can be effectively decolorized by stirring and washing with anhydrous ethanol at 40? for 1.5h.Finally,this system was used to expand the substrate and the effect was good.The second synthesis system uses chlorobenzene as the reaction solvent,Naphthol AS-PH was synthesized from 2-hydroxy3-naphthalic acid and o-ethoxylaniline,The molecular structure of the product was characterized by nuclear magnetism and liquid phase,and the influence of catalyst type,catalyst dosage,reaction solvent,addition method,reaction temperature,reaction time and material ratio on the reaction was discussed.Study found that chlorobenzene as solvent,the amount of 10mol%3,5-Bis(trifluoromethyl)benzeneboronic acid as catalyst,2-hydroxy-3-naphthalic acid and o-ethoxyaniline mole ratio was 1.2:1,first at reflux temperature2-hydroxy-3-naphthalic acid with catalyst pre-reaction 1h,and then continue to add adjacent ethoxy aniline reaction 60 h,under the optimum reaction conditions,the yield of naphthol AS-PH could reach 94.4%,the catalyst can be recycled three times,at the same time the use of molecular sieve has significant effect in the reaction.On this basis,the influence of anhydrous methanol content on product purity was discussed.The results showed that when the anhydrous methanol content was 5.5 times of the theoretical naphthol,the product purity reached more than 99%.Finally,this system was used to expand the substrate and the effect was good.Compared with the traditional industrial production route,the development of the two synthetic systems has the advantages of simple reaction steps,less waste and higher product purity.And on the basis of the small scale experiments,the synthetic amplification study was carried out to further improve the technical parameters of the small scale experiments. |
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