Preparation Of Pd@CNTs Hydrogenation Catalyst And Its Application In NMPA Synthesis

NMPA,namely N-methyl-4-aminoanisole,is an effective nonmetallic ether gasoline antiknock additive.Catalysts have played a vital role in improving the selection of single N-methyl compounds in the process of preparation of NMPA by p-anisidine N-alkyl reaction.For the synthesis of NMPA by p-anisidine N-alkyl reaction,the preparation of Pd@CNTs catalyst with high conversion and high selectivity was studied in this paper,and its catalytic performance was evaluated in detail.This paper first discusses the reaction system of NMPA prepared by the two step process of p-anisidine N-alkyl reaction and the influence of the selection of different carbon based materials on the catalyst,and characterizes catalyst using NMR,X-ray diffraction,scanning electron microscope,BET,ICP-OES and HPLC-MS techniques.Then,the catalytic performance of the catalyst is discussed based on p-anisidine N-alkyl reaction.Finally,the catalytic reaction conditions were optimized under the optimal catalyst,which laid the technical foundation for the production of NMPA in industry.The specific research content is as follows:(1)State briefly the classification,application and preparation method of Pd/C catalyst;State briefly N-alkyl synthesis technology,analysis of the basic principle of N-alkyl catalysis and the application of N-alkylation catalyst;In the process of Pd/C catalyst preparation,impregnation method has the advantages of simple preparation process,high efficiency,high Pd load and so on;(2)The preparation of Pd@CNTs catalyst with carbon nanotubes as carbon-based was studied and compared with activated carbon(powdery),acetylene black and reduced graphene oxide as carbon-based for the preparation of Pd@AC,Pd@AB and Pd@RGO catalysts;The Pd content of different catalysts was analyzed by ICP,the results showed that the Pd content of Pd@CNTs catalyst reached 34.45%;The specific surface area of Pd@CNTs catalyst was characterized,the results showed that the specific surface area was 113.42m~2/g and the average pore diameter was 88.82?;(3)Pd@CNTs catalyst has better catalytic performance for p-anisidine N-alkyl reaction than the purchased Pd/C catalyst,conversion rate,NMPA generation rate and selectivity under the optimal conditions(4MPa,2h)are 93.70%,84.94%and 90.65%,respectively.CoMPares to the purchased Pd/C catalyst,the prepared Pd@CNTs catalyst reduces the reaction pressure of the best conditions(from 6MPa to 4MPa).