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采用沉淀法和化学混合法 ,制备了用于椰子油加氢改性的 Ni/硅藻土和 Ni/Si O2 催化剂 .用原子吸收、碘价分析、活性和 BET比表面积测定及 XRD、 TG- DTA、 IR等手段 ,对催化剂和产物进行了物理和化学表征 .结果表明 ,控制合适的制备条件 ,用上述两种方法都可以制得活性很好的单元镍催化剂 ,且加氢后除熔点升高外 ,未改变油脂的其它物理性质 .沉淀法 ( Ni/硅藻土 )的制备条件对催化剂的实际镍含量与加氢活性有很大影响 .催化剂中镍含量与活性不呈线性关系 ,镍含量最佳值为 1 7%左右 .化学混合法 ( Ni/Si O2 )可以控制镍含量 ,且催化剂活性随镍含量增加而提高 ,镍含量在 2 0 %左右活性最高 .尽管硅藻土和用溶胶 -凝胶法制备的二氧化硅表面积相差悬殊 ,但硅藻土的低比表面积不影响催化剂的活性 ,载体表面积与催化剂的活性之间没有必然的联系 .镍原子的晶粒度、活性组分与载体的相互作用以及载体的内表面利用率则影响催化剂的活性 .
The Ni / diatomite and Ni / Si O2 catalysts for the hydrogenation of coconut oil were prepared by precipitation and chemical mixing method.The atomic absorption, iodine value, activity and BET specific surface area, XRD, TG- DTA, IR and other means, the catalysts and products were characterized by physical and chemical methods.The results showed that under the control of suitable preparation conditions, the active nickel catalysts could be prepared by the above two methods, High and no change in the other physical properties of the grease precipitation conditions (Ni / diatomaceous earth) preparation conditions on the actual nickel content of the catalyst and hydrogenation activity has a great influence on the catalyst nickel content and activity is not linear, nickel The optimum content of Ni is about 7% .The chemical reaction (Ni / Si O2) can control the nickel content, and the catalytic activity increases with the increase of nickel content, while the nickel content is about 20% However, the low specific surface area of diatomite does not affect the activity of the catalyst, and there is no necessary relationship between the surface area of the support and the activity of the catalyst. The grain size of nickel atom, The interaction of the active ingredient with the carrier and the utilization of the inner surface of the carrier then affect the activity of the catalyst.