Preparation Of Nanoporous Metal Pt Catalyst And Its Application In Hydrogenation Of M-Dinitrobenzene

Pt-based metal catalysts have been applied widely in various fields.In order to utilize the active sites of Pt efficiently,it is a very effective method to prepare metal into porous structure.M-Phenylenediamine(m-MPD)is an important organic compound that is widely used.Therefore,how to develop an efficient catalyst for M-Dinitrobenzene(m-DNB)hydrogenation is particularly important.Pt can catalyze the hydrogenation of nitro groups to amine groups at normal temperature and pressure,but the M-Nitroaniline(m-PDA)intermediate produced during the production process is not easy to desorb on the surface of Pt,resulting in lower selectivity of m-MPD.Due to the concave surface structure of the nanoporous material,two nitro groups in m-DNB molecules are simultaneously activated by adsorption.Therefore,this article explores the preparation of nanoporous platinum catalyst and its catalytic performance.The specific work is as follows:In the first part of the work,a series of nickel-platinum alloy with different metal ratios was obtained by chemical reduction method using sodium borohydride as a reducing agent,and then the nanoporous Pt was prepared by dealloying method.In order to make it evenly dispersed and convenient for recovery,it was supported on the silica carrier.Applied the prepared catalysts to the catalytic hydrogenation of m-DNB to m-MPD.Finally,m-MPD was obtained in 135 minutes at room temperature and pressure.The catalyst cycle stability is good,which has potential application value.The second part of the work improved the catalyst preparation method of the first part.Using L-ascorbic acid as a reducing agent,PVP as a pore-forming agent and dispersant,the nanoporous platinum-copper alloy was successfully prepared.In order to make it evenly dispersed and convenient for recovery,it was supported on alumina.By adjusting and optimizing the preparation conditions,such as the amount of PVP,m-MPD was obtained in 90 minutes under normal temperature and pressure conditions,the activity was greatly improved.It has also obtained a good catalytic effect when it was applied to the hydrogenation of nitrobenzene to nitroaniline orother nitro-compounds.It has a better practical application prospect.The third part of the work is based on the second part.Pyrrole and its derivatives have important application value in the fields of medicine and organic synthesis.The use of HY-shaped molecular sieves can catalyze aniline and furan to prepare pyrrole and its derivatives.However,aniline is easy to oxidize and difficult to store,the author decided to support the nanoporous platinum-copper alloy prepared in the second part on the HY molecular sieve to prepare a bifunctional catalyst for nitrobenzene-furan tandem synthesis of pyrrole and derivatives.