高效雷尼镍催化1,4-丁炔二醇加氢制备1,4-丁二醇

High efficient catalysis for hydrogenation of 1,4-butynediol to 1,4-butanediol via Raney nickel

通过控制加热电流大小制备了不同Ni_(2)Al_(3)质量分数的镍铝合金。选取高Ni_(2)Al_(3)质量分数的合金进行预刻蚀和二次刻蚀处理,得到2种颗粒状雷尼镍催化剂,采用ICP、BET、XRD、XPS、SEM对2种雷尼镍催化剂进行了表征,并将其用于1,4-丁炔二醇(BYD)加氢制1,4-丁二醇(BDO)。结果表明,二次刻蚀法得到的雷尼镍在140℃、5 MPa压力、反应时间1.0 h的条件下催化BYD加氢,BYD转化率可达100%,BDO收率为92.0%;而预刻蚀雷尼镍达到相同BDO收率所需时间为3.0 h。二次刻蚀得到的催化剂的比表面积比预刻蚀得到的催化剂更大,达到12.83 m^(2)/g;并且其表面微观结构更粗糙,富含缺陷活性位,Ni元素质量分数达到了63.36%。此外,金属Ni分散性提高、表面金属Al完全消失及Al和Ni的氧化物增多,均使催化剂表面的骨架结构更加稳定,显著提高了催化剂的催化活性。

Nickel-aluminum alloys with different Ni_(2)Al_(3) mass fractions were prepared by controlling the heating current.Two kinds of granular Raney nickel catalysts were then synthesized,respectively,by pre-etching and two-step etching of the nickel-aluminum alloy with high Ni_(2)Al_(3) mass fraction,and were characterized by ICP,BET,XRD,XPS and SEM,and then were used for hydrogenation of 1,4-butynediol(BYD)to 1,4-butanediol(BDO).The results showed that under the conditions of temperature of 140℃,pressure of 5 MPa and reaction time of 1.0 h,the catalyst obtained by two-step etching achieved a BYD conversion rate of 100%and a BDO yield of 92.0%,while it took 3.0 h for the pre-etching catalyst to obtain the same BDO yield.Compared with that obtained by pre-etching method,the catalyst obtained by two-step etching method exhibited larger specific surface area(12.83 m^(2)/g),more obvious surface microstructure,more abundant defective active sites,with the mass fraction of Ni reaching 63.36%.In addition,the increased dispersion of metal Ni,the complete disappearance of metal Al and the increase of Al and Ni oxides all made the skeleton structure of the catalyst surface more stable,which significantly improved its catalytic activity.