Fabrication Of Lewis Acid-surfactant Combined Catalyst By Solid-phase Grinding And Its Catalytic Application

At present,more and more countries in the world take "green chemical production" as one of the first prerequisity for development.Researchers in organic synthesis,analytical chemistry,catalysis and other fields have responded positively to the call of green chemistry to develop more environmentally friendly technologies by reducing resource consumption and waste emissions.Especially in organic synthesis,the choice of green reagents and catalysts is more conducive to the realization of the goal of green chemistry.With the continuous development of green chemical technology,"lewis acid-surfactant composite catalyst(LASCs)" has been widely applied in green organic catalytic synthesis,however,The traditional catalyst preparation method(water phase preparation method)has many problems,such as large consumption of water,large amount of waste water and easy to cause environmental pollution.so developping more environmentally friendly synthesis technology is of great significance.In order to overcome shortcomings in the preparation and application of LASCs,we researched the preparation of dodecyl sulfate salts(DS salts)LASCs by solvent-free(water)solid phase grinding method,and researched its catalytic performance.The main research content and result are as follows:1.Using sodium dodecyl sulfate(SDS)and metallic nitrate as raw materials,9 different dodecyl sulfate salts(M(DS)x)(M=Zr,x=4;Fe,Al,Ce,Y,La,x=3;The Sr,Cr,Pb,x=2)were parpared.The optimized reaction process parameters:1 mmol metallic nitrate and mmol SDS are ground at room temperature for 30 min.After the reaction,using 15 mL of water for filtration and washing for 3 times.And then vacuum drying for 12 h at room temperature.In general,the yield of different salt products is between 60%and 90%.The result shows that the amount of water is reduced by at least five times in the reaction process,so it is known that solid phase grinding method is a new and environmentally friendly and effective technique for the preparation of dodecyl sulfate.2.The composition and structure,crystal phase characteristics and particle morphology of the salt were characterized and analyzed by XRD,SEM,FT-IR and NMR.XRD and FT-IR results show that the M(DS)x to the bilayer structure,This kind of salts is the product of the complexation of lauryl sulfate ions and metal ions.Different metal ions lead to different kinds of salts with different plane spacing and diffraction peak positions.The dissociation pattern and position symmetry of OSO3-are mainly related to the interaction between metal ions and SDS.it was found that M(DS)x prepared by different metal salts had different morphologies through SEM:the nanometer linear shape with Pb(DS)2 and the block-like structure of other metal salts.3.The preparation of Pb(DS)2 in gram scale has also be researched.10 mmol(3.3450 g)Pb(NO3)2 and 20 mmol(5.7680 g)SDS are ground in a ball mill for 30 min.And then washing them with 150 mL water for 3 times.The yield of the product can reach 80%.The amplification test results of DS salt shows that the solid-phase grinding method is easy to be amplified and the process conditions were stable.4.Given the special morphology of Pb(DS)2,we mainly examines the catalytic properties of Pb(DS)2 in solvent(water)cinnamic acid of esterification reaction.In the esterification reaction between cinnamic acid and n-butanol,M(DS)x was used as catalyst to catalyze the esterification reaction of cinnamic acid.The results showed that the catalytic activity of Pb(DS)2 was the best.when the dosage of Pb(DS)2 to 30 mg,acid alcohol than 1 mmol:6 mmol,The yield of products reached 94%after 6 h reaction at 80 ?,the catalytic effect is betterSimilarly,the catalyst was also effective in other esterification reactions.5.Taking the reaction of indol and benzaldehyde as an example,the results showed that the optimal conditions for water reaction were 40 mg catalyst,pure water as the solvent,45 minutes of reaction at room temperature,the product yield could reach 93%,and the optimal conditions for solid reaction are:50 mg catalyst,0.3 g SiO2,50 Hz grinding frequency,grinding for 30 min,the product yield could reach 98%.