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关于硅铝裂化催化剂的酸性的性质和由来存在着一系列的不同理论.甚至测定硅铝催化剂酸性的适当方法也是争论的问题.本文作者用同样的步骤,但用不同氧化铝含量,并用不同的溶液进行离子交换,制备了不同的共胶硅铝催化剂,并研究了它们的酸性.每个催化剂在陪烧前后用几种已知的方法来测定酸性.此外作者还提出了一种新的,基于催化剂在氢氧化钾水溶液中的吸附等温线的酸性测定方法.用这些不同方法所得的数据和催化剂的裂化活性作了比较.根据本工作所得的结果,作者讨论了在催化剂制备过程中酸性中心形成的机理,并提出了下列看法:在共胶硅铝催化剂的表面上存在着不同性质和不同强度的酸性中心,包括路易(Lewis)酸中心和质子酸中心.作者认为这类催化剂的活性主要是由具有两个铝原子的质子酸中心所产生的,虽然某些其它类型的酸性中心也可能在不同程度上具有催化活性。
A number of different theories exist regarding the nature and origin of the acidity of the aluminosilicate cracking catalyst.Even the proper method of determining the acidity of the aluminosilicate catalyst is also a matter of debate.The authors used the same procedure but with different alumina contents and different Solution was ion-exchanged to prepare different co-silica-alumina catalysts and their acidity was studied.At the same time, several known methods were used to determine the acidity of each catalyst before and after calcination.In addition, the authors also proposed a new, Based on the acidity determination of the adsorption isotherm of the catalyst in potassium hydroxide aqueous solution, the data obtained by these different methods are compared with the cracking activity of the catalyst.According to the results obtained in this work, the authors discuss the acidity centers And proposed the following observations: There are acidic sites with different properties and different intensities on the surface of the co-silica-alumina catalyst, including the Lewis acid center and the protonic acid center. The authors believe that the activity of these catalysts is mainly Is produced by a protonic acid center with two aluminum atoms, although some other types of acidic centers are also possible Catalytically active to varying degrees.