1,2-环己二醇脱氢Ni-Na/硅藻土催化剂的制备

Preparation of Ni-Na/Diatomite Catalysts for the Dehydrogenation of 1,2-Cyclohexanediol

采用均相沉淀法和等体积浸渍法制备了Ni-Na/硅藻土催化剂,考察了粘结剂和扩孔剂对催化剂结构的影响,并考察了活性组分Ni含量对催化剂性能的影响。采用BET、XRD,NH3-TPD对催化剂进行了测试分析。结果表明,粘结剂氧化铝粉的加入可以大幅度地提高催化剂的机械强度,并确定了加入氧化铝粉的质量分数为20%最佳;增加活性组分Ni的含量,Ni-Na/硅藻土催化剂的脱氢性能先升后降,以含Ni质量分数为30%最佳;添加扩孔剂PEG20000改变了催化剂的结构,增大了孔径,提高了催化剂对目标产物邻苯二酚的选择性。通过对Ni-Na/硅藻土催化剂的固定床反应研究发现,当反应温度为320℃,反应压力为101.3 k Pa,液时空速为1.0h-1时,1,2-环己二醇的转化率为99.4%,邻苯二酚的选择性为93.0%,催化剂的抗压强度为85 N/cm。

Ni-Na/diatomite catalysts with different contents of Ni and different binders and poreexpanding agents were prepared by homogeneous precipitation method and equivalent-volume impregnation method,and their catalytic performance was studied.The catalysts were characterized by means of BET,XRD,and NH3-TPD.The addition of Al2O3 greatly enhanced the mechanical strength of the catalyst,and the optimum content of Al2O3 was 20%.With the increase of Ni,the dehydrogenation of Ni-Na/diatomite catalysts increased first and then decreased,and the catalysts with Ni content of30% exhibited the best catalytic performance.The adjunction of PEG20000 changed the catalytic construction by increasing the pore size and specific surface area of the catalyst,hence improved selectivity of the target product catechol.The research of the fixed bed reaction shows that under the reaction conditions of 320 ℃ and 101.3 k Pa,the liquid space velocity was 1.0 h^-1,the conversion of cyclohexanediol and the selectivity of catechol for the catalyst Ni/Na diatomite reached 99.4% and93.0%,respectively,and the mechanical strength of the catalyst was 85 N/cm.