Nitrosomonas europaea, an autotrophic bacteria, can catalyze both the oxidation of ammonia to nitrite and methane to methanol by ammonia monooxygenase (AMO). N. europaea obtains electrons for the AMO reaction by oxidation of ammonia and hydroxylamine. Therefore, the effects of ammonia and hydroxylamine on AMO activity and methanol production by the whole cells of N. europaea were investigated. The addition of electron donors increased both AMO activity and methanol production. The optimal methanol production was achieved by either the repeated addition of 100 μM (1 M = 1 mol·dm−3) ammonium chloride every 30 min, or 200 μM ammonium chloride every 1 h during reaction to the final concentration of 1 mM. During 6 h reaction, 440 μM methanol was accumulated, 47% higher compared with no addition of electron donor or 30% higher compared with the one time addition of 1 mM ammonium chloride before reaction.
The oxidative dehydrogenation of ethane (ODHE) over POn/NiO/ZrO2 (High Surface area Zirconia: HSZ) catalyst was carried out with a fix-bed flow reactor at 450°C under atmospheric pressure. The ODHE without dilution of reactants with inert gas resulted in ethane conversion of 32.1%, with a high ethene selectivity of 64.2% and an ethene yield of 20.6%. In addition, the catalytic activity did not decrease for at least 12 h. In XPS analysis, Ni species of NiO/HSZ catalyst after the reaction exhibited partly reduced metallic Ni. In contrast, in POn/NiO/HSZ, Ni species exhibited mostly the NiO form after the reaction. It was found to be important for high ethane conversion and ethene selectivity, the Ni species not to be reduced to metallic Ni during the ODHE reaction. The addition of a small amount of POn to NiO/HSZ catalyst significantly contributed to the resistance to the facile reduction of NiO.
A new hydrocarbon conversion process called High Severity FCC (HS-FCC) has been developed to maximize propylene production in oil refineries. HS-FCC propylene yield was maximized using a combination of three factors; catalyst properties, reaction conditions and reactor design. Optimization of reaction conditions and catalyst development found that high reaction temperature accelerated catalytic cracking rather than hydrogen transfer. As a result, olefin/paraffin ratio of the product was higher at high reaction temperatures. Short contact time suppressed undesirable reactions such as hydrogen transfer and thermal cracking. High catalyst/oil (C/O) ratio accelerated catalytic cracking over thermal cracking, which also accelerated at high reaction temperatures. High C/O ratio is necessary to maintain high reaction temperature by transferring enough heat from regenerator to reactor in commercial FCC units. Catalyst properties were investigated to maximize olefin production at high reaction temperatures. A proprietary catalyst containing low acid density zeolite suppressed hydrogen transfer and maximized olefin production.
The desulfurization performance of solid superacid type adsorbent (sulfated alumina) for commercial kerosene was evaluated on batch system and on continuous flow system. Adsorptive desulfurization using acidic adsorbent, especially sulfated alumina, is promising method for desulfurization of commercial kerosene at moderate condition. The acid property seemed to effect on adsorption performance. Adsorbents combination of 4.1 l, 0.3 l of activated carbon supporting copper oxide and silver oxide and 3.8 l of Lewis acid type sulfate alumina in series, was evaluated for long term adsorptive desulfurization of commercial kerosene without using hydrogen at ambient temperature at a flow rate of 105 cm3/h, which corresponds the flow rate of about 350 W scale of PEFC. Thiophene type and benzothiophene type sulfur compounds had not leaked for more than 2300 h. Dibenzothiophene (DBT) type sulfur compounds had not also leaked until 810 h, and it reached 0.02 mass ppm at 2000 h, and then 0.03 mass ppm at 2300 h. Especially C3-alkyl-DBT was difficult to be removed.
The basic strength of alkali metal ion-exchanged β-zeolites was assessed based on the extent of Knoevenagel reaction using malonic acid derivatives and benzaldehyde. Preparation of chalcone and flavanone derivatives from the condensation of 2’-hydroxyacetophenones and benzaldehyde were carried out over the zeolites. The conversions of chalcone and flavanone derivatives and the selectivity of flavanone derivatives increased with the basic strength of the catalyst. A cyclization from chalcone to flavanone was controlled with intermolecular hydrogen bond strength of chalcone derivatives.
The effect of co-existing organics on the selective reduction of NO using ammonia as a reducing agent was investigated over Cu/ZSM-5 catalysts. Addition of organics in the feed gas resulted in deactivation of the catalysts. NH3-SCR activity at 200°C decreased in the following order, acetaldehyde > n-decane > methyl decanoate, p-xylene > m-xylene. After oxidation of the deactivated catalysts in an oxygen flow at 500°C, the activity of the catalyst was recovered. Hence, the cause of the deactivation was considered to be a carbonaceous material deposited over the catalyst.
An oil sorbent sheet made of nonwoven polypropylene fiber and a vial with screw cap were assessed as the test kit for sampling and preservation of liquid volatile petroleum samples in the forensic science field. Motor gasoline and kerosene were used as the petroleum samples. The analytical results of headspace gas chromatograph mass spectrometer (HSGCMS) revealed that this kit was much more retentive and stainless for petroleum samples than the gauze and plastic bag used in the conventional kit. This kit is suitable for sampling and preservation of petroleum samples obtained at crime scenes or floating on water. Petroleum sampled and preserved with this kit can be introduced directly into the auto sampler and analyzed promptly by HSGCMS.
Five different synthetic antioxidants were evaluated to improve the oxidation stability of high polyunsaturated biodiesel fuel produced by transesterification of fish oil. Butylhydroxy toluene (BHT), propyl 3,4,5-trihydroxybenzoate and dodecyl 3,4,5-trihydroxybenzoate were not effective for improvement of the oxidation stability of the fish oil biodiesel, whereas t-butylhydroquinone (TBHQ) showed best performance to improve oxidation stability. In 5 mass% fish oil biodiesel/tetradecane mixture, the antioxidation effect of BHT continued longer than that of TBHQ because of the difference of solubility against the mixed solution.
Catalytic activity and selectivity of Ni-Fe-Ce oxide nano-composites prepared by the solution-spray plasma technique for the high temperature water-gas-shift reaction were investigated. The composite catalyst exhibited higher activity than a commercial Fe-Cr catalyst at 673 K. Compared with an Ni-Fe-Al oxide nano-composite prepared by the same method, the CO methanation reaction was suppressed remarkably, without serious loss of activity for the water-gas-shift reaction.