Oxide-modified HZSM-5 zeolite

Table 6.13 Adsorption properties of oxide-modified HZSM-5 zeolite...

Mao D, Xia J, Zhang B, Lu G (2010) Highly efficient synthesis of dimethyl ether from syngas over the admixed catalyst of CuO-ZnO-ALOs and antimony oxide modified HZSM-5 zeolite. Energy Convers Manag 51 1134—1139... 

In this paper, we have investigated the oxidation of fluorobenzenes on the modified HZSM-5 zeolites using nitrous oxide as an oxidizing agent. 

Metal oxides on zeolites have also found use as redox catalysts. High-temperature (700-750 °C) dehydroaromatization of methane under nonoxidizing conditions has been explored with a number of zeolitic catalysts modified with transition metal ions. Although coke formation at these high temperatures is a problem, calcined molybdate-impregnated ZSM-5 shows unparalleled activity of up to 8 % methane conversion with 100 % selectivity towards aromatics. Surface studies of these Mo HZSM-5 catalysts indicate that M0O3 crystals are on the external zeolite surface [123]. 

We used HZSM-5 zeolites (Si02/AI203 = 40 - 120) and H[Ga]ZSM-5 zeolites (Si02/AI203 = 60) prepared by decationization of the Na-form with a 1 N aqueous solution of HCI. The preliminary activation of all catalyst samples was carried out at temperatures of 820 - 1120 K either in an Ar flow or in an air flow for 6 h. For comparison, we prepared the HZSM-5 zeolite modified by 2 wt % Cu (wet impregnation with a 1 M nitrate solution with further nitrate decomposition at 820 K in air) and tested this sample in the fluorobenzene oxidation by nitrous oxide. 

We studied the oxidation of fluorobenzene with nitrous oxide under the same conditions as reported in [8, 11]. Oxidation of monofluorobenzene on the HZSM-5 zeolite modified in such a way that strong Lewis acidity is induced in the sample... 

Unlike the acid form of the HZSM-5 zeolite studied, the HZSM-5 zeolite modified by 2 wt % Cu is active predominantly in deep oxidation of fluorobenzene with the formation of C02 at 570 - 670 K or even lower temperatures. 

Kazansky VB, Kustov LM, Khodakov AM (1989) On the nature of active sites for dehydrogenation of saturated hydrocarbons in HZSM-5 zeoUtes modified by zinc and gtillium oxides. In Jacobs PA, van Santen RA (eds) Proceedings of the international conference on zeolities. Zeolites facts, figures, future. Studies in surface science and catalysis, vol 49, Ptirt B. Elsevier, Amsterdam, pp 1173-1182... 

The conversion of rapeseed oil on Mo oxide and Ni-modified nanocrystalline ZSM-5 zeolites [167] resulted in the total deoxygenation of the vegetable oil. The major products were light olefins C -Cj and aromatic hydrocarbons. Ni/HZSM-5 catalysts demonstrate a higher selectivity to light olefins, whereas Mo/HZSM-5 catalysts are more selective to aromatics ... 

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