Study On The Preparation Of 1,2-pentanediol With N-butyl Alcohol As Raw Material

1,2-pentanediol has a very wide range of applications,this paper is based on the study of domestic and international 1,2-pentanediol synthesis method design of a new synthesis method,the synthesis method mainly includes the following aspects:1.Preparation of n-butanal with n-butyl alcohol as raw aterial.Study the effects of oxidant PCC,KMn O4 /OH-,Mn O₂ / OH-,Dess-Martin and TEMPO system on n-butyl alcohol oxidation.The optimum oxidation system is TEMPO system,and the optimum reaction conditions as follows: the reaction time is 10 min,the reaction temperature is 0?,raw material ratio is 1: 1.1,p H is 9.5,the best solvent is CH2Cl2.The results showed that under the optimum conditions,the yield of n-butanal is93.2%.The TEMPO system is effective and recyclable,and analysis the oxidation mechanism of TEMPO oxidation system.2.Preparation of 1,2-epoxy pentane with n-butanal by Ylide reaction.The optimum conditions as follows: suitable alkali is cesium carbonate,and the suitable solvent is the acetonitrile.Three methyl iodide sulfide and n-butanal ratio is 2: 1,the suitable reaction time is 2h,and the suitable reaction temperature is 0?.Under the condition of the process parameters the yield of 1,2-epoxy pentane is 91.3%,and analysis the reaction mechanism of the reaction of n-butanal to 1,2-epoxy pentane.3.Under certain conditions,1,2-epoxy pentane hydrolysis to produce 1,2-pentanediol.The results show that the SO₄^2-/ Fe₂O₃ solid catalyst is the best catalyst for hydrolysis,under the action of this catalyst,the optimum conditions for hydrolysis of 1,2-epoxy pentane as follows: suitable reaction temperature is 50 ?,suitable reaction time is 2h,the optimum amount of catalyst is 1% of the mass of 1,2-epoxy pentane and the optimum mass ratio of 1,2-epoxy pentane and water is 1: 3.Under the reaction conditions,1,2-epoxy pentane hydrolysis to 1,2-pentanediol yields up to 100%.4.The product n-butanal,1,2-epoxy pentane and 1,2-pentanediol are characterized by 1HNMR,FT-IR,MS and GC.The high purity 1,2-pentanediol is prepared by extraction,washing,filtering,and rectification and so on.The catalyst is recovered by filter.The catalyst is activated and recycled.Sample and analysis the water phase.The waste water flows through the column of ion exchange resin.Put forward the waste water treatment method.