Modification Of H? And Its Catalytic Performance For Preparing Sec-butanol Via Transesterification Method

Sec-butanol is an important industrial raw material for the production of methyl ethyl ketone.The consumption of methyl ethyl ketone is about 90%of the total consumption.With the increasing demand for high-grade coatings in China,the demand for methyl ethyl ketone continues to increase.Therefore,the demand for sec-butyl alcohol in the domestic market has also increased significantly.Accelerating the production of sec-butanol to promote the development and production of methyl ethyl ketone,not only can save a lot of foreign exchange,but also have better economic benefits.The traditional method for preparing sec-butanol is mainly via n-butene hydration.It has the disadvantages of severe equipment corrosion,high energy consumption and low yield.Therefore,it is of great significance to find out a new method for preparing sec-butanol.In addition,in recent years,with the continuous increase of sec-butyl acetate,the supply of sec-butyl acetate exceeds the demand in overall the market.Therefore,the technology of preparing sec-butanol from sec-butyl acetate via transesterification,hydrolysis,or hydrogenation techniques has been developed one after another.In this paper,sec-butanol were prepared from sec-butyl acetate and methanol via transesterification method by using modified H?zeolite as the catalyst.The effects of modification methods including Zr?SO₄?₂ loading,SO₄^2-/ZrO₂ loading,nitrogen doping,and K₂CO₃ were investigated.The physicochemical properties and the catalytic performance of the resulted H?zeolite were evaluated,and the results show:?1?The effects of Zr?SO₄?₂ loading and calcination temperature on the acidity,pore structure and catalytic performance of transesterification of H?zeolite were investigated.The results show that with the increase of the amount of Zr?SO₄?₂ loading,the Br?nsted?B?acid amount of H?zeolite increased,and its BET surface area,total pore volume,mesopore pore volume and pore size decreased obviously;but with the rising of calcination temperature of Zr?SO₄?₂-loaded H?zeolite,the BET surface area,total pore volume,mesopore pore volume and pore diameter of the obtained sample increased slightly,but it was still lower than that of unloaded H?zeolite.The evaluation results indicate that compared to those of unloaded H?zeolite,the catalytic activity of Zr?SO₄?₂-loaded H?zeolite in transesterification process and the yield and selectivity of sec-butanol were significantly improved;and when the loading amout of Zr?SO₄?₂ was20 wt.%,the calcination temperature was at 200 ^oC,the yield of sec-butanol can reach43.2%and the selectivity can reach 87.1%.?2?The effect of solid superacid SO₄^2-/ZrO₂ loading on the acidity,pore structure and catalytic performance for transesterification of H?zeolite was investigated.The results show that with the increasing amount of SO₄^2-/ZrO₂ loading,the amount of B acids in H?zeolite increased,while its BET surface area,total pore volume,mesopore pore volume and pore size decreased significantly.The evaluation results show that,after loading SO₄^2-/ZrO₂,the catalytic activity of H?zeolite,and the selectivity and the yield of sec-butanol were significantly improved,and when the SO₄^2-/ZrO₂ loading was50 wt.%and the calcination temperature was 550 ^oC,the yield of sec-butanol is up to40.5%,and the selectivity of sec-butanol is up to about 90%.?3?The H?zeolite was modified by nitrogen-doping and nitrogen-doping followed by K₂CO₃ loading,and the effects of the amount of nitrogen and K₂CO₃ on its acid-basic properties,pore structure and catalytic performance of transesterification of H?zeolite were investigated.The results show that after nitrogen-doping,the amount of acid of H?zeolite decreased and the amount of alkali increased significantly.With the increase of doping temperature and time,texture parameters were all significantly reduced.The evaluation results show that the catalytic activity of the nitrogen-doped H?zeolite was significantly reduced,and after loading K₂CO₃,the yield and selectivity of sec-butanol were also significantly reduced compared to those of unmodified H?zeolite.