Acetonitrile Hydrogenation Of Triethylamine Catalyst And Production Process Research And Development

Amorphous alloys represent a new class materials with short-range ordering while long-range disordering structure which may provide pathways to design excellent catalysts with high catalytic activity, better selectivity, and strong resistance to the sulfur and amine poison. Besides, less or even no environmental pollution occurred during the catalyst preparation and its application in catalysis. These amorphous catalysts have caused much attention owing to the industrial reqirements on the atomic reactions and green chemistry. Although the study of amorphous alloy catalysts only covers two decades, plenty of experimental datas have strongly shown a good potential for their industrial application.In the present thesis, both the ultrafine and supported Ni (Co)-B amorphous alloys and the bimetallic amorphous alloys (Ni-Co-B and Co-Fe-B) were prepared by chemical reduction. Their catalytic performances were measured by using liquid phase acetonitrile hydrogenation to ethylamine, an important reaction to develop new application of acetonitrile, a main byproduct during the acrylonitrile production. The relationship between the catalytic performances and the structural and electronic characteristics was systematically studied by combining a series of characterizations and the kinetic studies. The promoting effects of the amorphous structure, the alloying B, the Co-dopant or Fe-dopant, the SiO2 support on the catalytic properties, including activity, selectivity andthermal stability were investigated and discussed briefly. The follows are in details:1. Catalyst preparation. By adding KBH4 into a solution containing (1) NiCl2 only, (2) CoCl2 only, (3) both NiCl2 and CoCl2, and (4) both CoCl2 and FeCl3 a set of amorphous alloy catalysts were prepared. After washed thoroughly with distilled water, they were stored in in distilled water for use. Supported Ni-Co-B/SiO2 amorphous catalyst was prepared by impregnating SiO2 support with Ni2+ and Co2+ solution, followed by drying, calcinations, and KBH4 reducing. The Ni-Co-B/SiO2 obtained was washed and stroed in the similar way.2. Activity test. The acetonitrile hydrogenation was carried out in an autoclave containing certain amount of catalyst, solvent ethanol and acetonitrile at 3.0 MPahydrogen and 383 K. The hydrogenation activity was measured by monitoring the drop of the hydrogen pressure inside the autoclave. The acetonitrile conversion and the selectivity to ethylamine were obtained from product analysis by using gas chromatograph. All the amorphous alloy catalysts exhibit much higher catalytic activity than Raney Ni, showing a good potential for industrial application.3. The relationship between catalytic performance and the structure of the catalysts.(1) The amorphous alloys usually exhibited much higher activity than their corresponding crystalline counterpart. On one hand, in viewpoint of the structural effect, this could be attributed to the unique amorphous structure (i.e., the short-range ordering but long-range disordering structure), the homogeneous distribution of the active sites, and the highly coordinative unsaturation of these active sites. On the other hand, this could also be ascribed to the electronic interaction between the metal and the metalloid in the amorphous alloy. For all metal-B amorphous alloys, the metal always accepted partial electrons form the alloying B, making it electron-enriched while the B electron-deficient.(2) At higher temperature the amorphous alloy catalysts lost its catalytic activity significantly, possibly due to the crystalline transformation from their amorphous structure, the deconstructure of the metal-metalloid, as well as the agglomeration of alloy particles, which cause an abrupt decrease in the active surface area.(3) The activity raise of the Co-B amorphous alloy by doping Fe could be accounted for by considering its dispersion effect. The higher activity of the Ni-Co-B amorphous alloy than either the Ni-B or the Co-B was mainly attributed to the sygnetic effect between metallic Ni...