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π-Acceptor molecules covalently attached on hydrophilic support were used to selectively remove neutral nitrogen heterocyclic compounds from diesel feed by a charge transfer mechanism. Functionalized hydrophilic polymers can effectively adsorb nitrogen heterocyclic compounds with a high selectivity toward sulfur heterocyclic compounds from model and real feed. The results showed that charge transfer processes coupled with an ion-exchange process to selectively remove basic nitrogen compounds are efficient enough to produce denitrogenated feed in high yield. This study was conducted to determine whether trends in hydrodesulfurization (HDS) activity with lower sulfur content were mainly the result of lower reactivity of hindered sulfur compounds or due to nitrogen species inhibition. The inhibition effects of nitrogen compounds on HDS at conditions commonly used in the hydrotreatment of gas oil feedstocks has been experimentally determined. This study suggests that the selective removal of nitrogen compounds from gas oil strongly enhanced the deep desulfurization.

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The work deals with the effect of composition of CHA zeolites on the adsorption and separation of H2 and D2 under cryogenic temperatures. In the first part of this work the effect of Si/Al ratio and cationic composition on single gas adsorption of H2 and D2 was studied at 77.4 K. It was found that the adsorption capacities increase with Al content up to Si/Al = 2.1. Unexpectedly, Na-CHA zeolite with the highest Al content (Si/Al = 1.1) adsorbs only negligible amount because of the collapse of the zeolite structure upon dehydration at 400°C. The Na-and Li-containing chabazites with Si/Al = 2.1 possess similar adsorption capacities. In contrast, progressive replacement of Na + with K + results at 77.4 K in decreasing H2 and D2 adsorbed amount which becomes negligible for K + content higher than ~ 60 mol. %. In the second part of the work the D2/H2 thermodynamic selectivity for Na-, Li-and K-Na chabazites (Si/Al = 2.1) was measured using coadsorption technique at 40 -77.4 K in the pressure range 530 -650 hPa corresponding to high loading. The cationic composition is found to have only minor effect on the D2/H2 selectivity which increases exponentially with lowering temperature. For example in Na3.9Al3.9Si8.1O24 chabazite it rises from 2.6 at 77.4 K to 13 at 40 K. It is found that variation of D2/H2 selectivity with temperature is in a fair agreement with a simple quantum sieving model making use of the aperture size of the chabazite cavity as a unique adjustable parameter.

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A selective removal of nitrogen compounds from gasoils is proposed, using a recyclable sorbent capable of forming charge-transfer complexes; the selective elimination of nitrogen compounds strongly improves the hydrodesulfurization (HDS) of denitrogenated feed.