Catalytic activity of pyrite on coal liquefaction has been investigated with a 5 L batch-autoclave. The following conclusions are obtained.
(1) Pulverized pyrite exhibits high catalytic activiy because pulverization increases its outer surface area and its contact rate with reactants.
(2) Pulverization of pyrite also causes the crystal structure change which increases the number of active-site.
(3) It is inferred that catalytic activity of pyrite is related to chemical state of Fe and S on its surface.

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Two levels of hydro-desulfurizing experiments using FCC decant oil were performed with a conventional petroleum hydrorefining catalyst in order to obtain detailed information on hydro-desulfurizing of feed oil and coke derived from it. Hydro-desulfurizing products and the feed decant oil were analyzed by the HPLC-MS method, and the carbonization was carried out in a small batch reactor after which properties of coke produced were measured.
There is no difference with sulfur condensation ratios in cokes formed from hydro- desulfurized and unhydro-desulfurized feedstocks. Low sulfur coke clearly can be produced from low sulfur feedstocks which have beenhydro-desulfurized. Coke coefficient of thermal expansion (CTE) decreases by feedstock hydro-desulfurizing, but coke CTE from the more severely hydro-desulfurized decant oil is higher than that from the mildly hydro-desulfurized decant oil. Under the severehydro-desulfurizing conditions, hydrogenation of aromatic rings occurs, as does naphthenic ring opening and dealkylation. Severehydro-desulfurizing also causes a decrease in hydrogen donor ability and an increase in the carbon number of alkyl side chain for one of compound classes.

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Reducing effects of nitric oxides (NO_x) exhausted from combustion systems have been studied by adding various azo compounds such as azodicarbonamide and 2, 2-azobis-isobutyronitrile to simulated exhaust gases in an electrically heated quartz flow reactor under different conditions of temperature, gas composition and residence period.
As a result, it is shown that azo compounds can reduce nearly 100% of NO_x in the simulated model exhaust gases at 750°C. We suggest that at elevated temperature azo compounds should decompose to produce NH₂, CN and alkyl radicals having NO_x reducing effects.

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