| Disulfide has important molecular and structural features in various biologically active compounds and fine chemicals.Organic disulfides are often encountered in organic compounds and are biologically important.Disulfide applications range from antioxidants,drugs,insecticides to rubber vulcanizing agents.In biological systems,the formation of disulfide is crucial for the folding of peptides and proteins into their biologically active conformations.A large number of disulfide bonds accumulate in proteins and many other biologically active molecules.Widely used in the industry,disulfide rubbers and elastomers as curing agents give them excellent tensile strength.Therefore,it is very important to develop a mild,efficient and sustainable disulfide method.At present,there are many methods for the synthesis of 2-naphthalene disulfide in the laboratory,and the conversion rate and yield are also high,but most of them do not have the conditions for industrial production.In addition,the content of2-naphthalene disulfide in domestic reagents is only about 92%,and there are no domestic factories that can achieve industrial production.Therefore,in-depth study of the synthesis of 2-naphthalene disulfide,large-scale industrial production,and further increase its yield and purity,is of great significance.In this paper,we first explored the synthesis of 2-naphthalene disulfide using2-naphthalenesulfonyl chloride,potassium iodide,sodium bisulfite and formic acid as reactants by reductive coupling.The products were synthesized by 1HNMR,13CNMR and FT-IR confirmation.Single-factor experiments were used to optimize the process.The molar ratio of 2-naphthalenesulfonyl chloride to formic acid,the molar ratio of2-naphthalenesulfonyl chloride to sodium bisulfite,the molar ratio of2-naphthalenesulfonyl chloride to potassium iodide,reaction temperature,and reaction time were investigated.The influence of factors such as water quality and water quality on the reaction resulted in better technological conditions for synthesis:the molar ratio of 2-naphthalenesulfonyl chloride to NaHSO3 was 1:4,the molar ratio of 2-naphthalenesulfonyl chloride to HCOOH was 1:3,2 The molar ratio of naphthalene sulfonyl chloride to KI is 1:3,the reaction time is 3 h,the reaction temperature is 100℃.,and the amount of solvent is 1 g of 2-naphthalenesulfonyl chloride 6 g of water.Secondly,through orthogonal experiments,the process was further optimized,and the best combination was obtained:the molar ratio of 2-naphthalenesulfonyl chloride to NaHSO3 was 1:4,the molar ratio of 2-naphthalenesulfonyl chloride to HCOOH was 1:3.5,2-The molar ratio of naphthalene sulfonyl to KI is 1:2.5,the reaction time is 2.5 hours,and the reaction temperature is 100℃.The yield of 2-naphthalene disulfide obtained was 69.72%.The recrystallization process of the obtained crude product was studied.First,two crystallization conditions were determined:one is a direct cooling method,and the other is a gradual cooling method.In these two methods,the liquid phase content of the crystallized product is determined.Using the second crystallization condition as the final condition;on the basis of gradual cooling of the crystallization conditions,ethyl acetate was used as a solvent,dichloromethane as a solvent,and a volume ratio of dichloromethane to petroleum ether of 1:1 as a solvent.The crystallization conditions determine the preferred crystallization solvent:the secondary crystallization with 1,2-dichloroethane as the solvent,the purity of the product can reach more than 96%. |
