Synthesis And Application Explore New PNP Ligands

Producing high selectivity α-olefin by ethylene oligomerization is an important researchdirection of ethylene industry. Since it was first described by Bollmann whoproduced1-octene through the use of Cr（Ⅲ）/PNP/MAO catalyst, the research to find newcatalyst systems has been a hot area of research. Process units which are specially to produce1-octene have not been seen over the world,1-octene in abroad is byproduct of ethyleneoligomerization or extractive separation. Therefore, developing independent intellectualproperty rights of ethylene selective tetramerization toward1-octene have importantimplications for speeding up Chinese petrochemical industry development.Chromium-based catalysts are used to produce1-octene with high selectivities at present.Nowadays, focus of the research and development of of ethylene tetramerization catalystsystem are as follows: one hand is the structural synthesis of novel ligands diphosphinoamineas PN-Cn-NP, PNN, NNO, NPN type and study steric and electronic form differentsubstituents on the existing structure of the ligand with affect the body and Cr(Ⅲ) in the caseof complex, thereby screening out the optimal catalyst system; the other hand is investigatethe influence of different types of co-catalyst in the catalyst system, trying to find cheap andefficient substituted cocatalyst MAO, reduce the cost of the catalyst system, in order tofacilitate the industrial production of ethylene tetramerization.The issue carried the new ethylene tetramerization catalyst design, the use of phosphorustrichloride and diphenyl different organic amine synthesized eight kinds of new diphosphineligand backbone amine ligands by1H NMR and X-ray diffraction to determine the ligandstructure. The ligand for the catalyst system and cocatalyst chromium center study, theoptimal catalyst filter, and the effects of temperature, Al/Cr, PNP/Cr, etc. Ethylenetetramerization reaction conditions the catalyst system performance determined best ethylenetetramerization1-octene process conditions. Liquid phase polymerization product wasanalyzed by gas chromatography.The results showed that the new diphosphinoamine (PNP) ligand to chromium, MAOconsisting of ethylene tetramerization catalyst system, the reaction temperature was50℃,Al/Cr is300, PNP/Cr under the conditions of1.5/1, the catalyst activity up to5.48×106g/(molCr h), liquid products1-octene selectivity of up to85.84%1-hexene and1-octene overall selectivity of up to87.2%.