Containing Molybdenum Catalyst Synthesis And Application Of Olefin Epoxidation

Molybdenum is a kind of relatively rich reserves in the earth's crust of gray transition metal,molybdenum catalysts are used as one of the epoxidation catalyst,receives much concern because of its advantages in non-toxic,low price and efficiency of the catalytic activity and selectivity.The traditional olefin epoxidation system will load molybdenum compounds as the catalyst;H₂O₂,UHP,ROOH,RCO3H or NaOCl as oxidant;CH2Cl2,ether such kind of organic solvent for reaction solvent.But in this reaction system process,catalyst of the active component is easy to lose,it is difficult to achieve the ideal catalytic effect and catalyst is difficult to be recycled.And organic solvent is volatile,flammable,easy to pollute the environment,it is not accord with the idea of green environmental protection advocated in recent years.This paper is to use the new synthesis polyoxomolybdate-based ionic liquid as catalyst,H₂O₂ as oxidant,using a few or even don't use the solvent catalyzed epoxidation of cyclooctene.the production can reach 95.0%above,the reaction in the catalytic epoxy system of catalytic activity cycle 5 times can still keep high catalytic activity and selectivity,no byproduct formation,and after reaction H₂O₂ only products H2O,which established a green environmental protection with no pollution and efficient reaction system.Also use the new synthesis polyoxomolybdate-based ionic liquid as catalyst,UHP as the oxidant,acetonitrile as the solvent,the yield can reach more than 79.6%.Firstly,this paper synthesizes a series of polyoxomolybdate-based ionic liquid[Cnmim]4[Mo8O26]?n = 4,5.8,10,14,16?,by IR,NMR to characterize it,and the results show that:synthesize high purity of polyoxomolybdate-based ionic liquid.Second,with the new synthesis series of polyoxomolybdate-based ionic liquid as catalyst,the cyclooctene as raw materials,H₂O₂ as oxidant,this paper studies the effect of catalyst,oxidant,and the solvent.When we put[Cnmim]4[Mo8O26]?n=10,14,16?as catalyst:cyclooctene 1 mmol,2.5 mmol oxidant,50 ?mol catalyst,under 45 ? temperature the solvent system is completed,production ratio can reach 99.7%;[Cnmim]4[Mo8O26]?n=4,5,8?as catalyst:cyclooctene for 1 mmol,2.5 mmol oxidant,50 ?mol catalyst,0.6 mL solvent,temperature for 45 ?,the yield can reach 95.4%.These tests show that the influence of catalyst affected the most,followed by oxidant and solvent,with high reaction selectivity,with no by-products generation during reaction process.And under the obtained condition,we made experiment with the polyoxomolybdate-based ionic liquid as the catalyst for several times,the experimental results show that the catalyst used after circulating 5 times can still have high catalytic activity,1,2-epoxy cyclooctane the yield do not reduce,from environmental protection,energy saving or economical point of view,they are very good catalysts.Meanwhile,in the same optimal condition,to the a series of different carbon number of ionic liquid catalytic performance comparison,found that as the number of carbon in the imidazole ring increase the catalytic performance increased greatly.At the same time this paper also studies a series of polyoxomolybdate-based ionic liquid as catalyst,the cyclohexene as raw materials,UHP as oxidant,The optimal conditions for lmmol substrate,2.5 mmol oxidant,1.4?mol catalyst,0.6 mL solvent,for 55? temperature,production rate reached 79.6%.Oxidants has great influence in the reaction,followed by catalyst,solvent has the minimum influence in the reaction,and the reaction with high selectivity,with no by-products generated during the process.In short,polyoxomolybdate-based ionic liquid as catalyst epoxidation of cyclooctene and cyclohexene,this system has the advantages that the reaction temperature is low and the catalytic activity and selectivity is high,product separation is simple,And the catalytic epoxidation of cyclooctene can do no longer use organic solvents,green,and many other advantages,it is practical in common life.